* [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6
@ 2024-02-06 12:09 Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 01/57] Revert "eventfs: Do not allow NULL parent to eventfs_start_creating()" Steven Rostedt
` (57 more replies)
0 siblings, 58 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
This is a backport of all the work that lead up to the work that Linus made
on eventfs. I trust Linus's version more so than the versions in 6.6 and
6.7. There may be plenty of hidden issues due to the design.
This is the update for 6.6. It includes Linus's updates as well as all the
patches leading up to them. As the eventfs work went in in two parts, half
went in in 6.6 and the other in 6.7, there were 6 backports that were done
custom to 6.6 as the bugs found in 6.7 were in 6.6 but implemented
differently. This series starts with reverting those 6 backports and then
applying the updated patches to get to Linus's simplification.
I ran these through my full test suite that I use before sending anything to
Linus, although I did not run my "bisect" test that walks through the
patches. The tests were just run on the end result.
This was created with the following command against v6.6.15, after reverting
the 6 patches:
git log --reverse --no-merges --pretty=oneline v6.6..origin/master fs/tracefs/ | cut -d' ' -f1 |
while read a; do if ! git cherry-pick -x $a; then break; fi ; done
Which adds -x to the cherry pick to add the upstream commit SHAs.
There was one patch in tracefs that didn't need to be backported and I removed
that one.
Beau Belgrave (1):
eventfs: Fix events beyond NAME_MAX blocking tasks
Erick Archer (1):
eventfs: Use kcalloc() instead of kzalloc()
Jiapeng Chong (1):
tracefs/eventfs: Modify mismatched function name
Linus Torvalds (7):
tracefs: remove stale 'update_gid' code
eventfs: Initialize the tracefs inode properly
tracefs: Avoid using the ei->dentry pointer unnecessarily
tracefs: dentry lookup crapectomy
eventfs: Remove unused d_parent pointer field
eventfs: Clean up dentry ops and add revalidate function
eventfs: Get rid of dentry pointers without refcounts
Nathan Chancellor (1):
eventfs: Use ERR_CAST() in eventfs_create_events_dir()
Steven Rostedt (Google) (46):
Revert "eventfs: Do not allow NULL parent to eventfs_start_creating()"
Revert "eventfs: Check for NULL ef in eventfs_set_attr()"
Revert "eventfs: Use simple_recursive_removal() to clean up dentries"
Revert "eventfs: Delete eventfs_inode when the last dentry is freed"
Revert "eventfs: Save ownership and mode"
Revert "eventfs: Remove "is_freed" union with rcu head"
eventfs: Remove eventfs_file and just use eventfs_inode
eventfs: Use eventfs_remove_events_dir()
eventfs: Fix failure path in eventfs_create_events_dir()
eventfs: Fix WARN_ON() in create_file_dentry()
eventfs: Fix typo in eventfs_inode union comment
eventfs: Remove extra dget() in eventfs_create_events_dir()
eventfs: Fix kerneldoc of eventfs_remove_rec()
eventfs: Remove "is_freed" union with rcu head
eventfs: Have a free_ei() that just frees the eventfs_inode
eventfs: Test for ei->is_freed when accessing ei->dentry
eventfs: Save ownership and mode
eventfs: Hold eventfs_mutex when calling callback functions
eventfs: Delete eventfs_inode when the last dentry is freed
eventfs: Remove special processing of dput() of events directory
eventfs: Use simple_recursive_removal() to clean up dentries
eventfs: Remove expectation that ei->is_freed means ei->dentry == NULL
eventfs: Do not invalidate dentry in create_file/dir_dentry()
eventfs: Use GFP_NOFS for allocation when eventfs_mutex is held
eventfs: Move taking of inode_lock into dcache_dir_open_wrapper()
eventfs: Do not allow NULL parent to eventfs_start_creating()
eventfs: Make sure that parent->d_inode is locked in creating files/dirs
eventfs: Have event files and directories default to parent uid and gid
eventfs: Fix file and directory uid and gid ownership
tracefs: Check for dentry->d_inode exists in set_gid()
eventfs: Fix bitwise fields for "is_events"
eventfs: Remove "lookup" parameter from create_dir/file_dentry()
eventfs: Stop using dcache_readdir() for getdents()
tracefs/eventfs: Use root and instance inodes as default ownership
eventfs: Have eventfs_iterate() stop immediately if ei->is_freed is set
eventfs: Do ctx->pos update for all iterations in eventfs_iterate()
eventfs: Read ei->entries before ei->children in eventfs_iterate()
eventfs: Shortcut eventfs_iterate() by skipping entries already read
eventfs: Have the inodes all for files and directories all be the same
eventfs: Do not create dentries nor inodes in iterate_shared
eventfs: Save directory inodes in the eventfs_inode structure
tracefs: Zero out the tracefs_inode when allocating it
eventfs: Warn if an eventfs_inode is freed without is_freed being set
eventfs: Restructure eventfs_inode structure to be more condensed
eventfs: Remove fsnotify*() functions from lookup()
eventfs: Keep all directory links at 1
----
fs/tracefs/event_inode.c | 1250 +++++++++++++++++++-----------------------
fs/tracefs/inode.c | 276 +++++-----
fs/tracefs/internal.h | 60 +-
include/linux/trace_events.h | 2 +-
include/linux/tracefs.h | 73 ++-
kernel/trace/trace.c | 7 +-
kernel/trace/trace.h | 4 +-
kernel/trace/trace_events.c | 311 +++++++----
8 files changed, 1029 insertions(+), 954 deletions(-)
^ permalink raw reply [flat|nested] 59+ messages in thread
* [v6.6][PATCH 01/57] Revert "eventfs: Do not allow NULL parent to eventfs_start_creating()"
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 02/57] Revert "eventfs: Check for NULL ef in eventfs_set_attr()" Steven Rostedt
` (56 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
This reverts commit 6abb8c223ce12078a0f2c129656a13338dfe960b.
The eventfs was not designed properly and may have some hidden bugs in it.
Linus rewrote it properly and I trust his version more than this one. Revert
the backported patches for 6.6 and re-apply all the changes to make it
equivalent to Linus's version.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
fs/tracefs/inode.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index 0292c6a2bed9..891653ba9cf3 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -509,15 +509,20 @@ struct dentry *eventfs_start_creating(const char *name, struct dentry *parent)
struct dentry *dentry;
int error;
- /* Must always have a parent. */
- if (WARN_ON_ONCE(!parent))
- return ERR_PTR(-EINVAL);
-
error = simple_pin_fs(&trace_fs_type, &tracefs_mount,
&tracefs_mount_count);
if (error)
return ERR_PTR(error);
+ /*
+ * If the parent is not specified, we create it in the root.
+ * We need the root dentry to do this, which is in the super
+ * block. A pointer to that is in the struct vfsmount that we
+ * have around.
+ */
+ if (!parent)
+ parent = tracefs_mount->mnt_root;
+
if (unlikely(IS_DEADDIR(parent->d_inode)))
dentry = ERR_PTR(-ENOENT);
else
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 02/57] Revert "eventfs: Check for NULL ef in eventfs_set_attr()"
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 01/57] Revert "eventfs: Do not allow NULL parent to eventfs_start_creating()" Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 03/57] Revert "eventfs: Use simple_recursive_removal() to clean up dentries" Steven Rostedt
` (55 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
This reverts commit d8f492a059728bbd397defbc9b8d2f4159d869b5.
The eventfs was not designed properly and may have some hidden bugs in it.
Linus rewrote it properly and I trust his version more than this one. Revert
the backported patches for 6.6 and re-apply all the changes to make it
equivalent to Linus's version.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
fs/tracefs/event_inode.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index efbdc47c74dc..5fcfb634fec2 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -113,14 +113,14 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
mutex_lock(&eventfs_mutex);
ef = dentry->d_fsdata;
- if (ef && ef->is_freed) {
+ if (ef->is_freed) {
/* Do not allow changes if the event is about to be removed. */
mutex_unlock(&eventfs_mutex);
return -ENODEV;
}
ret = simple_setattr(idmap, dentry, iattr);
- if (!ret && ef)
+ if (!ret)
update_attr(ef, iattr);
mutex_unlock(&eventfs_mutex);
return ret;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 03/57] Revert "eventfs: Use simple_recursive_removal() to clean up dentries"
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 01/57] Revert "eventfs: Do not allow NULL parent to eventfs_start_creating()" Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 02/57] Revert "eventfs: Check for NULL ef in eventfs_set_attr()" Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 04/57] Revert "eventfs: Delete eventfs_inode when the last dentry is freed" Steven Rostedt
` (54 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
This reverts commit 055907ad2c14838c90d63297f7bab8d180a5d844.
The eventfs was not designed properly and may have some hidden bugs in it.
Linus rewrote it properly and I trust his version more than this one. Revert
the backported patches for 6.6 and re-apply all the changes to make it
equivalent to Linus's version.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
fs/tracefs/event_inode.c | 71 +++++++++++++++++++++-------------------
1 file changed, 38 insertions(+), 33 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 5fcfb634fec2..7aa92b8ebc51 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -54,10 +54,12 @@ struct eventfs_file {
/*
* Union - used for deletion
* @llist: for calling dput() if needed after RCU
+ * @del_list: list of eventfs_file to delete
* @rcu: eventfs_file to delete in RCU
*/
union {
struct llist_node llist;
+ struct list_head del_list;
struct rcu_head rcu;
};
void *data;
@@ -274,6 +276,7 @@ static void free_ef(struct eventfs_file *ef)
*/
void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry)
{
+ struct tracefs_inode *ti_parent;
struct eventfs_inode *ei;
struct eventfs_file *ef;
@@ -294,6 +297,10 @@ void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry)
mutex_lock(&eventfs_mutex);
+ ti_parent = get_tracefs(dentry->d_parent->d_inode);
+ if (!ti_parent || !(ti_parent->flags & TRACEFS_EVENT_INODE))
+ goto out;
+
ef = dentry->d_fsdata;
if (!ef)
goto out;
@@ -866,29 +873,30 @@ static void unhook_dentry(struct dentry *dentry)
{
if (!dentry)
return;
- /*
- * Need to add a reference to the dentry that is expected by
- * simple_recursive_removal(), which will include a dput().
- */
- dget(dentry);
- /*
- * Also add a reference for the dput() in eventfs_workfn().
- * That is required as that dput() will free the ei after
- * the SRCU grace period is over.
- */
+ /* Keep the dentry from being freed yet (see eventfs_workfn()) */
dget(dentry);
+
+ dentry->d_fsdata = NULL;
+ d_invalidate(dentry);
+ mutex_lock(&eventfs_mutex);
+ /* dentry should now have at least a single reference */
+ WARN_ONCE((int)d_count(dentry) < 1,
+ "dentry %px (%s) less than one reference (%d) after invalidate\n",
+ dentry, dentry->d_name.name, d_count(dentry));
+ mutex_unlock(&eventfs_mutex);
}
/**
* eventfs_remove_rec - remove eventfs dir or file from list
* @ef: eventfs_file to be removed.
+ * @head: to create list of eventfs_file to be deleted
* @level: to check recursion depth
*
* The helper function eventfs_remove_rec() is used to clean up and free the
* associated data from eventfs for both of the added functions.
*/
-static void eventfs_remove_rec(struct eventfs_file *ef, int level)
+static void eventfs_remove_rec(struct eventfs_file *ef, struct list_head *head, int level)
{
struct eventfs_file *ef_child;
@@ -908,16 +916,14 @@ static void eventfs_remove_rec(struct eventfs_file *ef, int level)
/* search for nested folders or files */
list_for_each_entry_srcu(ef_child, &ef->ei->e_top_files, list,
lockdep_is_held(&eventfs_mutex)) {
- eventfs_remove_rec(ef_child, level + 1);
+ eventfs_remove_rec(ef_child, head, level + 1);
}
}
ef->is_freed = 1;
- unhook_dentry(ef->dentry);
-
list_del_rcu(&ef->list);
- call_srcu(&eventfs_srcu, &ef->rcu, free_rcu_ef);
+ list_add_tail(&ef->del_list, head);
}
/**
@@ -928,22 +934,28 @@ static void eventfs_remove_rec(struct eventfs_file *ef, int level)
*/
void eventfs_remove(struct eventfs_file *ef)
{
- struct dentry *dentry;
+ struct eventfs_file *tmp;
+ LIST_HEAD(ef_del_list);
if (!ef)
return;
+ /*
+ * Move the deleted eventfs_inodes onto the ei_del_list
+ * which will also set the is_freed value. Note, this has to be
+ * done under the eventfs_mutex, but the deletions of
+ * the dentries must be done outside the eventfs_mutex.
+ * Hence moving them to this temporary list.
+ */
mutex_lock(&eventfs_mutex);
- dentry = ef->dentry;
- eventfs_remove_rec(ef, 0);
+ eventfs_remove_rec(ef, &ef_del_list, 0);
mutex_unlock(&eventfs_mutex);
- /*
- * If any of the ei children has a dentry, then the ei itself
- * must have a dentry.
- */
- if (dentry)
- simple_recursive_removal(dentry, NULL);
+ list_for_each_entry_safe(ef, tmp, &ef_del_list, del_list) {
+ unhook_dentry(ef->dentry);
+ list_del(&ef->del_list);
+ call_srcu(&eventfs_srcu, &ef->rcu, free_rcu_ef);
+ }
}
/**
@@ -954,8 +966,6 @@ void eventfs_remove(struct eventfs_file *ef)
*/
void eventfs_remove_events_dir(struct dentry *dentry)
{
- struct eventfs_file *ef_child;
- struct eventfs_inode *ei;
struct tracefs_inode *ti;
if (!dentry || !dentry->d_inode)
@@ -965,11 +975,6 @@ void eventfs_remove_events_dir(struct dentry *dentry)
if (!ti || !(ti->flags & TRACEFS_EVENT_INODE))
return;
- mutex_lock(&eventfs_mutex);
- ei = ti->private;
- list_for_each_entry_srcu(ef_child, &ei->e_top_files, list,
- lockdep_is_held(&eventfs_mutex)) {
- eventfs_remove_rec(ef_child, 0);
- }
- mutex_unlock(&eventfs_mutex);
+ d_invalidate(dentry);
+ dput(dentry);
}
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 04/57] Revert "eventfs: Delete eventfs_inode when the last dentry is freed"
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (2 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 03/57] Revert "eventfs: Use simple_recursive_removal() to clean up dentries" Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 05/57] Revert "eventfs: Save ownership and mode" Steven Rostedt
` (53 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
This reverts commit ea4c30a0a73fb5cb2604539db550f1e620bb949c.
The eventfs was not designed properly and may have some hidden bugs in it.
Linus rewrote it properly and I trust his version more than this one. Revert
the backported patches for 6.6 and re-apply all the changes to make it
equivalent to Linus's version.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
fs/tracefs/event_inode.c | 150 ++++++++++++++++++++-------------------
1 file changed, 76 insertions(+), 74 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 7aa92b8ebc51..6a3f7502310c 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -53,12 +53,10 @@ struct eventfs_file {
const struct inode_operations *iop;
/*
* Union - used for deletion
- * @llist: for calling dput() if needed after RCU
* @del_list: list of eventfs_file to delete
* @rcu: eventfs_file to delete in RCU
*/
union {
- struct llist_node llist;
struct list_head del_list;
struct rcu_head rcu;
};
@@ -115,7 +113,8 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
mutex_lock(&eventfs_mutex);
ef = dentry->d_fsdata;
- if (ef->is_freed) {
+ /* The LSB is set when the eventfs_inode is being freed */
+ if (((unsigned long)ef & 1UL) || ef->is_freed) {
/* Do not allow changes if the event is about to be removed. */
mutex_unlock(&eventfs_mutex);
return -ENODEV;
@@ -259,13 +258,6 @@ static struct dentry *create_dir(struct eventfs_file *ef,
return eventfs_end_creating(dentry);
}
-static void free_ef(struct eventfs_file *ef)
-{
- kfree(ef->name);
- kfree(ef->ei);
- kfree(ef);
-}
-
/**
* eventfs_set_ef_status_free - set the ef->status to free
* @ti: the tracefs_inode of the dentry
@@ -278,20 +270,34 @@ void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry)
{
struct tracefs_inode *ti_parent;
struct eventfs_inode *ei;
- struct eventfs_file *ef;
+ struct eventfs_file *ef, *tmp;
/* The top level events directory may be freed by this */
if (unlikely(ti->flags & TRACEFS_EVENT_TOP_INODE)) {
+ LIST_HEAD(ef_del_list);
+
mutex_lock(&eventfs_mutex);
+
ei = ti->private;
+ /* Record all the top level files */
+ list_for_each_entry_srcu(ef, &ei->e_top_files, list,
+ lockdep_is_held(&eventfs_mutex)) {
+ list_add_tail(&ef->del_list, &ef_del_list);
+ }
+
/* Nothing should access this, but just in case! */
ti->private = NULL;
+
mutex_unlock(&eventfs_mutex);
- ef = dentry->d_fsdata;
- if (ef)
- free_ef(ef);
+ /* Now safely free the top level files and their children */
+ list_for_each_entry_safe(ef, tmp, &ef_del_list, del_list) {
+ list_del(&ef->del_list);
+ eventfs_remove(ef);
+ }
+
+ kfree(ei);
return;
}
@@ -305,13 +311,16 @@ void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry)
if (!ef)
goto out;
- if (ef->is_freed) {
- free_ef(ef);
- } else {
- ef->dentry = NULL;
- }
+ /*
+ * If ef was freed, then the LSB bit is set for d_fsdata.
+ * But this should not happen, as it should still have a
+ * ref count that prevents it. Warn in case it does.
+ */
+ if (WARN_ON_ONCE((unsigned long)ef & 1))
+ goto out;
dentry->d_fsdata = NULL;
+ ef->dentry = NULL;
out:
mutex_unlock(&eventfs_mutex);
}
@@ -838,53 +847,13 @@ int eventfs_add_file(const char *name, umode_t mode,
return 0;
}
-static LLIST_HEAD(free_list);
-
-static void eventfs_workfn(struct work_struct *work)
-{
- struct eventfs_file *ef, *tmp;
- struct llist_node *llnode;
-
- llnode = llist_del_all(&free_list);
- llist_for_each_entry_safe(ef, tmp, llnode, llist) {
- /* This should only get here if it had a dentry */
- if (!WARN_ON_ONCE(!ef->dentry))
- dput(ef->dentry);
- }
-}
-
-static DECLARE_WORK(eventfs_work, eventfs_workfn);
-
-static void free_rcu_ef(struct rcu_head *head)
+static void free_ef(struct rcu_head *head)
{
struct eventfs_file *ef = container_of(head, struct eventfs_file, rcu);
- if (ef->dentry) {
- /* Do not free the ef until all references of dentry are gone */
- if (llist_add(&ef->llist, &free_list))
- queue_work(system_unbound_wq, &eventfs_work);
- return;
- }
-
- free_ef(ef);
-}
-
-static void unhook_dentry(struct dentry *dentry)
-{
- if (!dentry)
- return;
-
- /* Keep the dentry from being freed yet (see eventfs_workfn()) */
- dget(dentry);
-
- dentry->d_fsdata = NULL;
- d_invalidate(dentry);
- mutex_lock(&eventfs_mutex);
- /* dentry should now have at least a single reference */
- WARN_ONCE((int)d_count(dentry) < 1,
- "dentry %px (%s) less than one reference (%d) after invalidate\n",
- dentry, dentry->d_name.name, d_count(dentry));
- mutex_unlock(&eventfs_mutex);
+ kfree(ef->name);
+ kfree(ef->ei);
+ kfree(ef);
}
/**
@@ -936,25 +905,58 @@ void eventfs_remove(struct eventfs_file *ef)
{
struct eventfs_file *tmp;
LIST_HEAD(ef_del_list);
+ struct dentry *dentry_list = NULL;
+ struct dentry *dentry;
if (!ef)
return;
- /*
- * Move the deleted eventfs_inodes onto the ei_del_list
- * which will also set the is_freed value. Note, this has to be
- * done under the eventfs_mutex, but the deletions of
- * the dentries must be done outside the eventfs_mutex.
- * Hence moving them to this temporary list.
- */
mutex_lock(&eventfs_mutex);
eventfs_remove_rec(ef, &ef_del_list, 0);
+ list_for_each_entry_safe(ef, tmp, &ef_del_list, del_list) {
+ if (ef->dentry) {
+ unsigned long ptr = (unsigned long)dentry_list;
+
+ /* Keep the dentry from being freed yet */
+ dget(ef->dentry);
+
+ /*
+ * Paranoid: The dget() above should prevent the dentry
+ * from being freed and calling eventfs_set_ef_status_free().
+ * But just in case, set the link list LSB pointer to 1
+ * and have eventfs_set_ef_status_free() check that to
+ * make sure that if it does happen, it will not think
+ * the d_fsdata is an event_file.
+ *
+ * For this to work, no event_file should be allocated
+ * on a odd space, as the ef should always be allocated
+ * to be at least word aligned. Check for that too.
+ */
+ WARN_ON_ONCE(ptr & 1);
+
+ ef->dentry->d_fsdata = (void *)(ptr | 1);
+ dentry_list = ef->dentry;
+ ef->dentry = NULL;
+ }
+ call_srcu(&eventfs_srcu, &ef->rcu, free_ef);
+ }
mutex_unlock(&eventfs_mutex);
- list_for_each_entry_safe(ef, tmp, &ef_del_list, del_list) {
- unhook_dentry(ef->dentry);
- list_del(&ef->del_list);
- call_srcu(&eventfs_srcu, &ef->rcu, free_rcu_ef);
+ while (dentry_list) {
+ unsigned long ptr;
+
+ dentry = dentry_list;
+ ptr = (unsigned long)dentry->d_fsdata & ~1UL;
+ dentry_list = (struct dentry *)ptr;
+ dentry->d_fsdata = NULL;
+ d_invalidate(dentry);
+ mutex_lock(&eventfs_mutex);
+ /* dentry should now have at least a single reference */
+ WARN_ONCE((int)d_count(dentry) < 1,
+ "dentry %p less than one reference (%d) after invalidate\n",
+ dentry, d_count(dentry));
+ mutex_unlock(&eventfs_mutex);
+ dput(dentry);
}
}
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 05/57] Revert "eventfs: Save ownership and mode"
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (3 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 04/57] Revert "eventfs: Delete eventfs_inode when the last dentry is freed" Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 06/57] Revert "eventfs: Remove "is_freed" union with rcu head" Steven Rostedt
` (52 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
This reverts commit 9aaee3eebc91dd9ccebf6b6bc8a5f59d04ef718b.
The eventfs was not designed properly and may have some hidden bugs in it.
Linus rewrote it properly and I trust his version more than this one. Revert
the backported patches for 6.6 and re-apply all the changes to make it
equivalent to Linus's version.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
fs/tracefs/event_inode.c | 107 ++++++---------------------------------
1 file changed, 16 insertions(+), 91 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 6a3f7502310c..a64d8fa39e54 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -40,8 +40,6 @@ struct eventfs_inode {
* @data: something that the caller will want to get to later on
* @is_freed: Flag set if the eventfs is on its way to be freed
* @mode: the permission that the file or directory should have
- * @uid: saved uid if changed
- * @gid: saved gid if changed
*/
struct eventfs_file {
const char *name;
@@ -63,22 +61,11 @@ struct eventfs_file {
void *data;
unsigned int is_freed:1;
unsigned int mode:31;
- kuid_t uid;
- kgid_t gid;
};
static DEFINE_MUTEX(eventfs_mutex);
DEFINE_STATIC_SRCU(eventfs_srcu);
-/* Mode is unsigned short, use the upper bits for flags */
-enum {
- EVENTFS_SAVE_MODE = BIT(16),
- EVENTFS_SAVE_UID = BIT(17),
- EVENTFS_SAVE_GID = BIT(18),
-};
-
-#define EVENTFS_MODE_MASK (EVENTFS_SAVE_MODE - 1)
-
static struct dentry *eventfs_root_lookup(struct inode *dir,
struct dentry *dentry,
unsigned int flags);
@@ -86,54 +73,8 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file);
static int dcache_readdir_wrapper(struct file *file, struct dir_context *ctx);
static int eventfs_release(struct inode *inode, struct file *file);
-static void update_attr(struct eventfs_file *ef, struct iattr *iattr)
-{
- unsigned int ia_valid = iattr->ia_valid;
-
- if (ia_valid & ATTR_MODE) {
- ef->mode = (ef->mode & ~EVENTFS_MODE_MASK) |
- (iattr->ia_mode & EVENTFS_MODE_MASK) |
- EVENTFS_SAVE_MODE;
- }
- if (ia_valid & ATTR_UID) {
- ef->mode |= EVENTFS_SAVE_UID;
- ef->uid = iattr->ia_uid;
- }
- if (ia_valid & ATTR_GID) {
- ef->mode |= EVENTFS_SAVE_GID;
- ef->gid = iattr->ia_gid;
- }
-}
-
-static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
- struct iattr *iattr)
-{
- struct eventfs_file *ef;
- int ret;
-
- mutex_lock(&eventfs_mutex);
- ef = dentry->d_fsdata;
- /* The LSB is set when the eventfs_inode is being freed */
- if (((unsigned long)ef & 1UL) || ef->is_freed) {
- /* Do not allow changes if the event is about to be removed. */
- mutex_unlock(&eventfs_mutex);
- return -ENODEV;
- }
-
- ret = simple_setattr(idmap, dentry, iattr);
- if (!ret)
- update_attr(ef, iattr);
- mutex_unlock(&eventfs_mutex);
- return ret;
-}
-
static const struct inode_operations eventfs_root_dir_inode_operations = {
.lookup = eventfs_root_lookup,
- .setattr = eventfs_set_attr,
-};
-
-static const struct inode_operations eventfs_file_inode_operations = {
- .setattr = eventfs_set_attr,
};
static const struct file_operations eventfs_file_operations = {
@@ -144,20 +85,10 @@ static const struct file_operations eventfs_file_operations = {
.release = eventfs_release,
};
-static void update_inode_attr(struct inode *inode, struct eventfs_file *ef)
-{
- inode->i_mode = ef->mode & EVENTFS_MODE_MASK;
-
- if (ef->mode & EVENTFS_SAVE_UID)
- inode->i_uid = ef->uid;
-
- if (ef->mode & EVENTFS_SAVE_GID)
- inode->i_gid = ef->gid;
-}
-
/**
* create_file - create a file in the tracefs filesystem
- * @ef: the eventfs_file
+ * @name: the name of the file to create.
+ * @mode: the permission that the file should have.
* @parent: parent dentry for this file.
* @data: something that the caller will want to get to later on.
* @fop: struct file_operations that should be used for this file.
@@ -173,7 +104,7 @@ static void update_inode_attr(struct inode *inode, struct eventfs_file *ef)
* If tracefs is not enabled in the kernel, the value -%ENODEV will be
* returned.
*/
-static struct dentry *create_file(struct eventfs_file *ef,
+static struct dentry *create_file(const char *name, umode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fop)
{
@@ -181,13 +112,13 @@ static struct dentry *create_file(struct eventfs_file *ef,
struct dentry *dentry;
struct inode *inode;
- if (!(ef->mode & S_IFMT))
- ef->mode |= S_IFREG;
+ if (!(mode & S_IFMT))
+ mode |= S_IFREG;
- if (WARN_ON_ONCE(!S_ISREG(ef->mode)))
+ if (WARN_ON_ONCE(!S_ISREG(mode)))
return NULL;
- dentry = eventfs_start_creating(ef->name, parent);
+ dentry = eventfs_start_creating(name, parent);
if (IS_ERR(dentry))
return dentry;
@@ -196,10 +127,7 @@ static struct dentry *create_file(struct eventfs_file *ef,
if (unlikely(!inode))
return eventfs_failed_creating(dentry);
- /* If the user updated the directory's attributes, use them */
- update_inode_attr(inode, ef);
-
- inode->i_op = &eventfs_file_inode_operations;
+ inode->i_mode = mode;
inode->i_fop = fop;
inode->i_private = data;
@@ -212,7 +140,7 @@ static struct dentry *create_file(struct eventfs_file *ef,
/**
* create_dir - create a dir in the tracefs filesystem
- * @ei: the eventfs_inode that represents the directory to create
+ * @name: the name of the file to create.
* @parent: parent dentry for this file.
* @data: something that the caller will want to get to later on.
*
@@ -227,14 +155,13 @@ static struct dentry *create_file(struct eventfs_file *ef,
* If tracefs is not enabled in the kernel, the value -%ENODEV will be
* returned.
*/
-static struct dentry *create_dir(struct eventfs_file *ef,
- struct dentry *parent, void *data)
+static struct dentry *create_dir(const char *name, struct dentry *parent, void *data)
{
struct tracefs_inode *ti;
struct dentry *dentry;
struct inode *inode;
- dentry = eventfs_start_creating(ef->name, parent);
+ dentry = eventfs_start_creating(name, parent);
if (IS_ERR(dentry))
return dentry;
@@ -242,8 +169,7 @@ static struct dentry *create_dir(struct eventfs_file *ef,
if (unlikely(!inode))
return eventfs_failed_creating(dentry);
- update_inode_attr(inode, ef);
-
+ inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
inode->i_op = &eventfs_root_dir_inode_operations;
inode->i_fop = &eventfs_file_operations;
inode->i_private = data;
@@ -380,9 +306,10 @@ create_dentry(struct eventfs_file *ef, struct dentry *parent, bool lookup)
inode_lock(parent->d_inode);
if (ef->ei)
- dentry = create_dir(ef, parent, ef->data);
+ dentry = create_dir(ef->name, parent, ef->data);
else
- dentry = create_file(ef, parent, ef->data, ef->fop);
+ dentry = create_file(ef->name, ef->mode, parent,
+ ef->data, ef->fop);
if (!lookup)
inode_unlock(parent->d_inode);
@@ -548,7 +475,6 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
if (d) {
struct dentry **tmp;
-
tmp = krealloc(dentries, sizeof(d) * (cnt + 2), GFP_KERNEL);
if (!tmp)
break;
@@ -623,14 +549,13 @@ static struct eventfs_file *eventfs_prepare_ef(const char *name, umode_t mode,
return ERR_PTR(-ENOMEM);
}
INIT_LIST_HEAD(&ef->ei->e_top_files);
- ef->mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
} else {
ef->ei = NULL;
- ef->mode = mode;
}
ef->iop = iop;
ef->fop = fop;
+ ef->mode = mode;
ef->data = data;
return ef;
}
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 06/57] Revert "eventfs: Remove "is_freed" union with rcu head"
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (4 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 05/57] Revert "eventfs: Save ownership and mode" Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 07/57] eventfs: Remove eventfs_file and just use eventfs_inode Steven Rostedt
` (51 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
This reverts commit fa18a8a0539b02cc621938091691f0b73f0b1288.
The eventfs was not designed properly and may have some hidden bugs in it.
Linus rewrote it properly and I trust his version more than this one. Revert
the backported patches for 6.6 and re-apply all the changes to make it
equivalent to Linus's version.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
fs/tracefs/event_inode.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index a64d8fa39e54..8c8d64e76103 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -38,7 +38,6 @@ struct eventfs_inode {
* @fop: file_operations for file or directory
* @iop: inode_operations for file or directory
* @data: something that the caller will want to get to later on
- * @is_freed: Flag set if the eventfs is on its way to be freed
* @mode: the permission that the file or directory should have
*/
struct eventfs_file {
@@ -53,14 +52,15 @@ struct eventfs_file {
* Union - used for deletion
* @del_list: list of eventfs_file to delete
* @rcu: eventfs_file to delete in RCU
+ * @is_freed: node is freed if one of the above is set
*/
union {
struct list_head del_list;
struct rcu_head rcu;
+ unsigned long is_freed;
};
void *data;
- unsigned int is_freed:1;
- unsigned int mode:31;
+ umode_t mode;
};
static DEFINE_MUTEX(eventfs_mutex);
@@ -814,8 +814,6 @@ static void eventfs_remove_rec(struct eventfs_file *ef, struct list_head *head,
}
}
- ef->is_freed = 1;
-
list_del_rcu(&ef->list);
list_add_tail(&ef->del_list, head);
}
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 07/57] eventfs: Remove eventfs_file and just use eventfs_inode
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (5 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 06/57] Revert "eventfs: Remove "is_freed" union with rcu head" Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 08/57] eventfs: Use eventfs_remove_events_dir() Steven Rostedt
` (50 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Ajay Kaher
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Instead of having a descriptor for every file represented in the eventfs
directory, only have the directory itself represented. Change the API to
send in a list of entries that represent all the files in the directory
(but not other directories). The entry list contains a name and a callback
function that will be used to create the files when they are accessed.
struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry *parent,
const struct eventfs_entry *entries,
int size, void *data);
is used for the top level eventfs directory, and returns an eventfs_inode
that will be used by:
struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode *parent,
const struct eventfs_entry *entries,
int size, void *data);
where both of the above take an array of struct eventfs_entry entries for
every file that is in the directory.
The entries are defined by:
typedef int (*eventfs_callback)(const char *name, umode_t *mode, void **data,
const struct file_operations **fops);
struct eventfs_entry {
const char *name;
eventfs_callback callback;
};
Where the name is the name of the file and the callback gets called when
the file is being created. The callback passes in the name (in case the
same callback is used for multiple files), a pointer to the mode, data and
fops. The data will be pointing to the data that was passed in
eventfs_create_dir() or eventfs_create_events_dir() but may be overridden
to point to something else, as it will be used to point to the
inode->i_private that is created. The information passed back from the
callback is used to create the dentry/inode.
If the callback fills the data and the file should be created, it must
return a positive number. On zero or negative, the file is ignored.
This logic may also be used as a prototype to convert entire pseudo file
systems into just-in-time allocation.
The "show_events_dentry" file has been updated to show the directories,
and any files they have.
With just the eventfs_file allocations:
Before after deltas for meminfo (in kB):
MemFree: -14360
MemAvailable: -14260
Buffers: 40
Cached: 24
Active: 44
Inactive: 48
Inactive(anon): 28
Active(file): 44
Inactive(file): 20
Dirty: -4
AnonPages: 28
Mapped: 4
KReclaimable: 132
Slab: 1604
SReclaimable: 132
SUnreclaim: 1472
Committed_AS: 12
Before after deltas for slabinfo:
<slab>: <objects> [ * <size> = <total>]
ext4_inode_cache 27 [* 1184 = 31968 ]
extent_status 102 [* 40 = 4080 ]
tracefs_inode_cache 144 [* 656 = 94464 ]
buffer_head 39 [* 104 = 4056 ]
shmem_inode_cache 49 [* 800 = 39200 ]
filp -53 [* 256 = -13568 ]
dentry 251 [* 192 = 48192 ]
lsm_file_cache 277 [* 32 = 8864 ]
vm_area_struct -14 [* 184 = -2576 ]
trace_event_file 1748 [* 88 = 153824 ]
kmalloc-1k 35 [* 1024 = 35840 ]
kmalloc-256 49 [* 256 = 12544 ]
kmalloc-192 -28 [* 192 = -5376 ]
kmalloc-128 -30 [* 128 = -3840 ]
kmalloc-96 10581 [* 96 = 1015776 ]
kmalloc-64 3056 [* 64 = 195584 ]
kmalloc-32 1291 [* 32 = 41312 ]
kmalloc-16 2310 [* 16 = 36960 ]
kmalloc-8 9216 [* 8 = 73728 ]
Free memory dropped by 14,360 kB
Available memory dropped by 14,260 kB
Total slab additions in size: 1,771,032 bytes
With this change:
Before after deltas for meminfo (in kB):
MemFree: -12084
MemAvailable: -11976
Buffers: 32
Cached: 32
Active: 72
Inactive: 168
Inactive(anon): 176
Active(file): 72
Inactive(file): -8
Dirty: 24
AnonPages: 196
Mapped: 8
KReclaimable: 148
Slab: 836
SReclaimable: 148
SUnreclaim: 688
Committed_AS: 324
Before after deltas for slabinfo:
<slab>: <objects> [ * <size> = <total>]
tracefs_inode_cache 144 [* 656 = 94464 ]
shmem_inode_cache -23 [* 800 = -18400 ]
filp -92 [* 256 = -23552 ]
dentry 179 [* 192 = 34368 ]
lsm_file_cache -3 [* 32 = -96 ]
vm_area_struct -13 [* 184 = -2392 ]
trace_event_file 1748 [* 88 = 153824 ]
kmalloc-1k -49 [* 1024 = -50176 ]
kmalloc-256 -27 [* 256 = -6912 ]
kmalloc-128 1864 [* 128 = 238592 ]
kmalloc-64 4685 [* 64 = 299840 ]
kmalloc-32 -72 [* 32 = -2304 ]
kmalloc-16 256 [* 16 = 4096 ]
total = 721352
Free memory dropped by 12,084 kB
Available memory dropped by 11,976 kB
Total slab additions in size: 721,352 bytes
That's over 2 MB in savings per instance for free and available memory,
and over 1 MB in savings per instance of slab memory.
Link: https://lore.kernel.org/linux-trace-kernel/20231003184059.4924468e@gandalf.local.home
Link: https://lore.kernel.org/linux-trace-kernel/20231004165007.43d79161@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ajay Kaher <akaher@vmware.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 5790b1fb3d672d9a1fe3881a7181dfdbe741568f)
---
fs/tracefs/event_inode.c | 847 ++++++++++++++++++-----------------
fs/tracefs/inode.c | 2 +-
fs/tracefs/internal.h | 37 +-
include/linux/trace_events.h | 2 +-
include/linux/tracefs.h | 29 +-
kernel/trace/trace.c | 7 +-
kernel/trace/trace.h | 4 +-
kernel/trace/trace_events.c | 313 +++++++++----
8 files changed, 705 insertions(+), 536 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 8c8d64e76103..eab18b157ef5 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -2,8 +2,9 @@
/*
* event_inode.c - part of tracefs, a pseudo file system for activating tracing
*
- * Copyright (C) 2020-23 VMware Inc, author: Steven Rostedt (VMware) <rostedt@goodmis.org>
+ * Copyright (C) 2020-23 VMware Inc, author: Steven Rostedt <rostedt@goodmis.org>
* Copyright (C) 2020-23 VMware Inc, author: Ajay Kaher <akaher@vmware.com>
+ * Copyright (C) 2023 Google, author: Steven Rostedt <rostedt@goodmis.org>
*
* eventfs is used to dynamically create inodes and dentries based on the
* meta data provided by the tracing system.
@@ -23,46 +24,6 @@
#include <linux/delay.h>
#include "internal.h"
-struct eventfs_inode {
- struct list_head e_top_files;
-};
-
-/*
- * struct eventfs_file - hold the properties of the eventfs files and
- * directories.
- * @name: the name of the file or directory to create
- * @d_parent: holds parent's dentry
- * @dentry: once accessed holds dentry
- * @list: file or directory to be added to parent directory
- * @ei: list of files and directories within directory
- * @fop: file_operations for file or directory
- * @iop: inode_operations for file or directory
- * @data: something that the caller will want to get to later on
- * @mode: the permission that the file or directory should have
- */
-struct eventfs_file {
- const char *name;
- struct dentry *d_parent;
- struct dentry *dentry;
- struct list_head list;
- struct eventfs_inode *ei;
- const struct file_operations *fop;
- const struct inode_operations *iop;
- /*
- * Union - used for deletion
- * @del_list: list of eventfs_file to delete
- * @rcu: eventfs_file to delete in RCU
- * @is_freed: node is freed if one of the above is set
- */
- union {
- struct list_head del_list;
- struct rcu_head rcu;
- unsigned long is_freed;
- };
- void *data;
- umode_t mode;
-};
-
static DEFINE_MUTEX(eventfs_mutex);
DEFINE_STATIC_SRCU(eventfs_srcu);
@@ -93,16 +54,9 @@ static const struct file_operations eventfs_file_operations = {
* @data: something that the caller will want to get to later on.
* @fop: struct file_operations that should be used for this file.
*
- * This is the basic "create a file" function for tracefs. It allows for a
- * wide range of flexibility in creating a file.
- *
- * This function will return a pointer to a dentry if it succeeds. This
- * pointer must be passed to the tracefs_remove() function when the file is
- * to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.) If an error occurs, %NULL will be returned.
- *
- * If tracefs is not enabled in the kernel, the value -%ENODEV will be
- * returned.
+ * This function creates a dentry that represents a file in the eventsfs_inode
+ * directory. The inode.i_private pointer will point to @data in the open()
+ * call.
*/
static struct dentry *create_file(const char *name, umode_t mode,
struct dentry *parent, void *data,
@@ -118,6 +72,7 @@ static struct dentry *create_file(const char *name, umode_t mode,
if (WARN_ON_ONCE(!S_ISREG(mode)))
return NULL;
+ WARN_ON_ONCE(!parent);
dentry = eventfs_start_creating(name, parent);
if (IS_ERR(dentry))
@@ -142,20 +97,11 @@ static struct dentry *create_file(const char *name, umode_t mode,
* create_dir - create a dir in the tracefs filesystem
* @name: the name of the file to create.
* @parent: parent dentry for this file.
- * @data: something that the caller will want to get to later on.
- *
- * This is the basic "create a dir" function for eventfs. It allows for a
- * wide range of flexibility in creating a dir.
- *
- * This function will return a pointer to a dentry if it succeeds. This
- * pointer must be passed to the tracefs_remove() function when the file is
- * to be removed (no automatic cleanup happens if your module is unloaded,
- * you are responsible here.) If an error occurs, %NULL will be returned.
*
- * If tracefs is not enabled in the kernel, the value -%ENODEV will be
- * returned.
+ * This function will create a dentry for a directory represented by
+ * a eventfs_inode.
*/
-static struct dentry *create_dir(const char *name, struct dentry *parent, void *data)
+static struct dentry *create_dir(const char *name, struct dentry *parent)
{
struct tracefs_inode *ti;
struct dentry *dentry;
@@ -172,7 +118,6 @@ static struct dentry *create_dir(const char *name, struct dentry *parent, void *
inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
inode->i_op = &eventfs_root_dir_inode_operations;
inode->i_fop = &eventfs_file_operations;
- inode->i_private = data;
ti = get_tracefs(inode);
ti->flags |= TRACEFS_EVENT_INODE;
@@ -185,18 +130,18 @@ static struct dentry *create_dir(const char *name, struct dentry *parent, void *
}
/**
- * eventfs_set_ef_status_free - set the ef->status to free
+ * eventfs_set_ei_status_free - remove the dentry reference from an eventfs_inode
* @ti: the tracefs_inode of the dentry
- * @dentry: dentry who's status to be freed
+ * @dentry: dentry which has the reference to remove.
*
- * eventfs_set_ef_status_free will be called if no more
- * references remain
+ * Remove the association between a dentry from an eventfs_inode.
*/
-void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry)
+void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
{
struct tracefs_inode *ti_parent;
+ struct eventfs_inode *ei_child, *tmp;
struct eventfs_inode *ei;
- struct eventfs_file *ef, *tmp;
+ int i;
/* The top level events directory may be freed by this */
if (unlikely(ti->flags & TRACEFS_EVENT_TOP_INODE)) {
@@ -207,9 +152,9 @@ void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry)
ei = ti->private;
/* Record all the top level files */
- list_for_each_entry_srcu(ef, &ei->e_top_files, list,
+ list_for_each_entry_srcu(ei_child, &ei->children, list,
lockdep_is_held(&eventfs_mutex)) {
- list_add_tail(&ef->del_list, &ef_del_list);
+ list_add_tail(&ei_child->del_list, &ef_del_list);
}
/* Nothing should access this, but just in case! */
@@ -218,11 +163,13 @@ void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry)
mutex_unlock(&eventfs_mutex);
/* Now safely free the top level files and their children */
- list_for_each_entry_safe(ef, tmp, &ef_del_list, del_list) {
- list_del(&ef->del_list);
- eventfs_remove(ef);
+ list_for_each_entry_safe(ei_child, tmp, &ef_del_list, del_list) {
+ list_del(&ei_child->del_list);
+ eventfs_remove_dir(ei_child);
}
+ kfree_const(ei->name);
+ kfree(ei->d_children);
kfree(ei);
return;
}
@@ -233,68 +180,162 @@ void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry)
if (!ti_parent || !(ti_parent->flags & TRACEFS_EVENT_INODE))
goto out;
- ef = dentry->d_fsdata;
- if (!ef)
+ ei = dentry->d_fsdata;
+ if (!ei)
goto out;
/*
- * If ef was freed, then the LSB bit is set for d_fsdata.
+ * If ei was freed, then the LSB bit is set for d_fsdata.
* But this should not happen, as it should still have a
* ref count that prevents it. Warn in case it does.
*/
- if (WARN_ON_ONCE((unsigned long)ef & 1))
+ if (WARN_ON_ONCE((unsigned long)ei & 1))
goto out;
+ /* This could belong to one of the files of the ei */
+ if (ei->dentry != dentry) {
+ for (i = 0; i < ei->nr_entries; i++) {
+ if (ei->d_children[i] == dentry)
+ break;
+ }
+ if (WARN_ON_ONCE(i == ei->nr_entries))
+ goto out;
+ ei->d_children[i] = NULL;
+ } else {
+ ei->dentry = NULL;
+ }
+
dentry->d_fsdata = NULL;
- ef->dentry = NULL;
-out:
+ out:
mutex_unlock(&eventfs_mutex);
}
+/**
+ * create_file_dentry - create a dentry for a file of an eventfs_inode
+ * @ei: the eventfs_inode that the file will be created under
+ * @e_dentry: a pointer to the d_children[] of the @ei
+ * @parent: The parent dentry of the created file.
+ * @name: The name of the file to create
+ * @mode: The mode of the file.
+ * @data: The data to use to set the inode of the file with on open()
+ * @fops: The fops of the file to be created.
+ * @lookup: If called by the lookup routine, in which case, dput() the created dentry.
+ *
+ * Create a dentry for a file of an eventfs_inode @ei and place it into the
+ * address located at @e_dentry. If the @e_dentry already has a dentry, then
+ * just do a dget() on it and return. Otherwise create the dentry and attach it.
+ */
+static struct dentry *
+create_file_dentry(struct eventfs_inode *ei, struct dentry **e_dentry,
+ struct dentry *parent, const char *name, umode_t mode, void *data,
+ const struct file_operations *fops, bool lookup)
+{
+ struct dentry *dentry;
+ bool invalidate = false;
+
+ mutex_lock(&eventfs_mutex);
+ /* If the e_dentry already has a dentry, use it */
+ if (*e_dentry) {
+ /* lookup does not need to up the ref count */
+ if (!lookup)
+ dget(*e_dentry);
+ mutex_unlock(&eventfs_mutex);
+ return *e_dentry;
+ }
+ mutex_unlock(&eventfs_mutex);
+
+ /* The lookup already has the parent->d_inode locked */
+ if (!lookup)
+ inode_lock(parent->d_inode);
+
+ dentry = create_file(name, mode, parent, data, fops);
+
+ if (!lookup)
+ inode_unlock(parent->d_inode);
+
+ mutex_lock(&eventfs_mutex);
+
+ if (IS_ERR_OR_NULL(dentry)) {
+ /*
+ * When the mutex was released, something else could have
+ * created the dentry for this e_dentry. In which case
+ * use that one.
+ *
+ * Note, with the mutex held, the e_dentry cannot have content
+ * and the ei->is_freed be true at the same time.
+ */
+ WARN_ON_ONCE(ei->is_freed);
+ dentry = *e_dentry;
+ /* The lookup does not need to up the dentry refcount */
+ if (dentry && !lookup)
+ dget(dentry);
+ mutex_unlock(&eventfs_mutex);
+ return dentry;
+ }
+
+ if (!*e_dentry && !ei->is_freed) {
+ *e_dentry = dentry;
+ dentry->d_fsdata = ei;
+ } else {
+ /*
+ * Should never happen unless we get here due to being freed.
+ * Otherwise it means two dentries exist with the same name.
+ */
+ WARN_ON_ONCE(!ei->is_freed);
+ invalidate = true;
+ }
+ mutex_unlock(&eventfs_mutex);
+
+ if (invalidate)
+ d_invalidate(dentry);
+
+ if (lookup || invalidate)
+ dput(dentry);
+
+ return invalidate ? NULL : dentry;
+}
+
/**
* eventfs_post_create_dir - post create dir routine
- * @ef: eventfs_file of recently created dir
+ * @ei: eventfs_inode of recently created dir
*
* Map the meta-data of files within an eventfs dir to their parent dentry
*/
-static void eventfs_post_create_dir(struct eventfs_file *ef)
+static void eventfs_post_create_dir(struct eventfs_inode *ei)
{
- struct eventfs_file *ef_child;
+ struct eventfs_inode *ei_child;
struct tracefs_inode *ti;
/* srcu lock already held */
/* fill parent-child relation */
- list_for_each_entry_srcu(ef_child, &ef->ei->e_top_files, list,
+ list_for_each_entry_srcu(ei_child, &ei->children, list,
srcu_read_lock_held(&eventfs_srcu)) {
- ef_child->d_parent = ef->dentry;
+ ei_child->d_parent = ei->dentry;
}
- ti = get_tracefs(ef->dentry->d_inode);
- ti->private = ef->ei;
+ ti = get_tracefs(ei->dentry->d_inode);
+ ti->private = ei;
}
/**
- * create_dentry - helper function to create dentry
- * @ef: eventfs_file of file or directory to create
- * @parent: parent dentry
- * @lookup: true if called from lookup routine
+ * create_dir_dentry - Create a directory dentry for the eventfs_inode
+ * @ei: The eventfs_inode to create the directory for
+ * @parent: The dentry of the parent of this directory
+ * @lookup: True if this is called by the lookup code
*
- * Used to create a dentry for file/dir, executes post dentry creation routine
+ * This creates and attaches a directory dentry to the eventfs_inode @ei.
*/
static struct dentry *
-create_dentry(struct eventfs_file *ef, struct dentry *parent, bool lookup)
+create_dir_dentry(struct eventfs_inode *ei, struct dentry *parent, bool lookup)
{
bool invalidate = false;
- struct dentry *dentry;
+ struct dentry *dentry = NULL;
mutex_lock(&eventfs_mutex);
- if (ef->is_freed) {
- mutex_unlock(&eventfs_mutex);
- return NULL;
- }
- if (ef->dentry) {
- dentry = ef->dentry;
- /* On dir open, up the ref count */
+ if (ei->dentry) {
+ /* If the dentry already has a dentry, use it */
+ dentry = ei->dentry;
+ /* lookup does not need to up the ref count */
if (!lookup)
dget(dentry);
mutex_unlock(&eventfs_mutex);
@@ -302,42 +343,44 @@ create_dentry(struct eventfs_file *ef, struct dentry *parent, bool lookup)
}
mutex_unlock(&eventfs_mutex);
+ /* The lookup already has the parent->d_inode locked */
if (!lookup)
inode_lock(parent->d_inode);
- if (ef->ei)
- dentry = create_dir(ef->name, parent, ef->data);
- else
- dentry = create_file(ef->name, ef->mode, parent,
- ef->data, ef->fop);
+ dentry = create_dir(ei->name, parent);
if (!lookup)
inode_unlock(parent->d_inode);
mutex_lock(&eventfs_mutex);
- if (IS_ERR_OR_NULL(dentry)) {
- /* If the ef was already updated get it */
- dentry = ef->dentry;
+
+ if (IS_ERR_OR_NULL(dentry) && !ei->is_freed) {
+ /*
+ * When the mutex was released, something else could have
+ * created the dentry for this e_dentry. In which case
+ * use that one.
+ *
+ * Note, with the mutex held, the e_dentry cannot have content
+ * and the ei->is_freed be true at the same time.
+ */
+ dentry = ei->dentry;
if (dentry && !lookup)
dget(dentry);
mutex_unlock(&eventfs_mutex);
return dentry;
}
- if (!ef->dentry && !ef->is_freed) {
- ef->dentry = dentry;
- if (ef->ei)
- eventfs_post_create_dir(ef);
- dentry->d_fsdata = ef;
+ if (!ei->dentry && !ei->is_freed) {
+ ei->dentry = dentry;
+ eventfs_post_create_dir(ei);
+ dentry->d_fsdata = ei;
} else {
- /* A race here, should try again (unless freed) */
- invalidate = true;
-
/*
* Should never happen unless we get here due to being freed.
* Otherwise it means two dentries exist with the same name.
*/
- WARN_ON_ONCE(!ef->is_freed);
+ WARN_ON_ONCE(!ei->is_freed);
+ invalidate = true;
}
mutex_unlock(&eventfs_mutex);
if (invalidate)
@@ -349,50 +392,85 @@ create_dentry(struct eventfs_file *ef, struct dentry *parent, bool lookup)
return invalidate ? NULL : dentry;
}
-static bool match_event_file(struct eventfs_file *ef, const char *name)
-{
- bool ret;
-
- mutex_lock(&eventfs_mutex);
- ret = !ef->is_freed && strcmp(ef->name, name) == 0;
- mutex_unlock(&eventfs_mutex);
-
- return ret;
-}
-
/**
* eventfs_root_lookup - lookup routine to create file/dir
* @dir: in which a lookup is being done
* @dentry: file/dir dentry
- * @flags: to pass as flags parameter to simple lookup
+ * @flags: Just passed to simple_lookup()
*
- * Used to create a dynamic file/dir within @dir. Use the eventfs_inode
- * list of meta data to find the information needed to create the file/dir.
+ * Used to create dynamic file/dir with-in @dir, search with-in @ei
+ * list, if @dentry found go ahead and create the file/dir
*/
+
static struct dentry *eventfs_root_lookup(struct inode *dir,
struct dentry *dentry,
unsigned int flags)
{
+ const struct file_operations *fops;
+ const struct eventfs_entry *entry;
+ struct eventfs_inode *ei_child;
struct tracefs_inode *ti;
struct eventfs_inode *ei;
- struct eventfs_file *ef;
+ struct dentry *ei_dentry = NULL;
struct dentry *ret = NULL;
+ const char *name = dentry->d_name.name;
+ bool created = false;
+ umode_t mode;
+ void *data;
int idx;
+ int i;
+ int r;
ti = get_tracefs(dir);
if (!(ti->flags & TRACEFS_EVENT_INODE))
return NULL;
- ei = ti->private;
+ /* Grab srcu to prevent the ei from going away */
idx = srcu_read_lock(&eventfs_srcu);
- list_for_each_entry_srcu(ef, &ei->e_top_files, list,
+
+ /*
+ * Grab the eventfs_mutex to consistent value from ti->private.
+ * This s
+ */
+ mutex_lock(&eventfs_mutex);
+ ei = READ_ONCE(ti->private);
+ if (ei)
+ ei_dentry = READ_ONCE(ei->dentry);
+ mutex_unlock(&eventfs_mutex);
+
+ if (!ei || !ei_dentry)
+ goto out;
+
+ data = ei->data;
+
+ list_for_each_entry_srcu(ei_child, &ei->children, list,
srcu_read_lock_held(&eventfs_srcu)) {
- if (!match_event_file(ef, dentry->d_name.name))
+ if (strcmp(ei_child->name, name) != 0)
continue;
ret = simple_lookup(dir, dentry, flags);
- create_dentry(ef, ef->d_parent, true);
+ create_dir_dentry(ei_child, ei_dentry, true);
+ created = true;
break;
}
+
+ if (created)
+ goto out;
+
+ for (i = 0; i < ei->nr_entries; i++) {
+ entry = &ei->entries[i];
+ if (strcmp(name, entry->name) == 0) {
+ void *cdata = data;
+ r = entry->callback(name, &mode, &cdata, &fops);
+ if (r <= 0)
+ continue;
+ ret = simple_lookup(dir, dentry, flags);
+ create_file_dentry(ei, &ei->d_children[i],
+ ei_dentry, name, mode, cdata,
+ fops, true);
+ break;
+ }
+ }
+ out:
srcu_read_unlock(&eventfs_srcu, idx);
return ret;
}
@@ -432,29 +510,48 @@ static int eventfs_release(struct inode *inode, struct file *file)
return dcache_dir_close(inode, file);
}
+static int add_dentries(struct dentry ***dentries, struct dentry *d, int cnt)
+{
+ struct dentry **tmp;
+
+ tmp = krealloc(*dentries, sizeof(d) * (cnt + 2), GFP_KERNEL);
+ if (!tmp)
+ return -1;
+ tmp[cnt] = d;
+ tmp[cnt + 1] = NULL;
+ *dentries = tmp;
+ return 0;
+}
+
/**
* dcache_dir_open_wrapper - eventfs open wrapper
* @inode: not used
- * @file: dir to be opened (to create its child)
+ * @file: dir to be opened (to create it's children)
*
- * Used to dynamically create the file/dir within @file. @file is really a
- * directory and all the files/dirs of the children within @file will be
- * created. If any of the files/dirs have already been created, their
- * reference count will be incremented.
+ * Used to dynamic create file/dir with-in @file, all the
+ * file/dir will be created. If already created then references
+ * will be increased
*/
static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
{
+ const struct file_operations *fops;
+ const struct eventfs_entry *entry;
+ struct eventfs_inode *ei_child;
struct tracefs_inode *ti;
struct eventfs_inode *ei;
- struct eventfs_file *ef;
struct dentry_list *dlist;
struct dentry **dentries = NULL;
- struct dentry *dentry = file_dentry(file);
+ struct dentry *parent = file_dentry(file);
struct dentry *d;
struct inode *f_inode = file_inode(file);
+ const char *name = parent->d_name.name;
+ umode_t mode;
+ void *data;
int cnt = 0;
int idx;
int ret;
+ int i;
+ int r;
ti = get_tracefs(f_inode);
if (!(ti->flags & TRACEFS_EVENT_INODE))
@@ -463,25 +560,51 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
if (WARN_ON_ONCE(file->private_data))
return -EINVAL;
+ idx = srcu_read_lock(&eventfs_srcu);
+
+ mutex_lock(&eventfs_mutex);
+ ei = READ_ONCE(ti->private);
+ mutex_unlock(&eventfs_mutex);
+
+ if (!ei) {
+ srcu_read_unlock(&eventfs_srcu, idx);
+ return -EINVAL;
+ }
+
+
+ data = ei->data;
+
dlist = kmalloc(sizeof(*dlist), GFP_KERNEL);
- if (!dlist)
+ if (!dlist) {
+ srcu_read_unlock(&eventfs_srcu, idx);
return -ENOMEM;
+ }
- ei = ti->private;
- idx = srcu_read_lock(&eventfs_srcu);
- list_for_each_entry_srcu(ef, &ei->e_top_files, list,
+ list_for_each_entry_srcu(ei_child, &ei->children, list,
srcu_read_lock_held(&eventfs_srcu)) {
- d = create_dentry(ef, dentry, false);
+ d = create_dir_dentry(ei_child, parent, false);
if (d) {
- struct dentry **tmp;
+ ret = add_dentries(&dentries, d, cnt);
+ if (ret < 0)
+ break;
+ cnt++;
+ }
+ }
- tmp = krealloc(dentries, sizeof(d) * (cnt + 2), GFP_KERNEL);
- if (!tmp)
+ for (i = 0; i < ei->nr_entries; i++) {
+ void *cdata = data;
+ entry = &ei->entries[i];
+ name = entry->name;
+ r = entry->callback(name, &mode, &cdata, &fops);
+ if (r <= 0)
+ continue;
+ d = create_file_dentry(ei, &ei->d_children[i],
+ parent, name, mode, cdata, fops, false);
+ if (d) {
+ ret = add_dentries(&dentries, d, cnt);
+ if (ret < 0)
break;
- tmp[cnt] = d;
- tmp[cnt + 1] = NULL;
cnt++;
- dentries = tmp;
}
}
srcu_read_unlock(&eventfs_srcu, idx);
@@ -514,63 +637,90 @@ static int dcache_readdir_wrapper(struct file *file, struct dir_context *ctx)
}
/**
- * eventfs_prepare_ef - helper function to prepare eventfs_file
- * @name: the name of the file/directory to create.
- * @mode: the permission that the file should have.
- * @fop: struct file_operations that should be used for this file/directory.
- * @iop: struct inode_operations that should be used for this file/directory.
- * @data: something that the caller will want to get to later on. The
- * inode.i_private pointer will point to this value on the open() call.
+ * eventfs_create_dir - Create the eventfs_inode for this directory
+ * @name: The name of the directory to create.
+ * @parent: The eventfs_inode of the parent directory.
+ * @entries: A list of entries that represent the files under this directory
+ * @size: The number of @entries
+ * @data: The default data to pass to the files (an entry may override it).
+ *
+ * This function creates the descriptor to represent a directory in the
+ * eventfs. This descriptor is an eventfs_inode, and it is returned to be
+ * used to create other children underneath.
+ *
+ * The @entries is an array of eventfs_entry structures which has:
+ * const char *name
+ * eventfs_callback callback;
+ *
+ * The name is the name of the file, and the callback is a pointer to a function
+ * that will be called when the file is reference (either by lookup or by
+ * reading a directory). The callback is of the prototype:
*
- * This function allocates and fills the eventfs_file structure.
+ * int callback(const char *name, umode_t *mode, void **data,
+ * const struct file_operations **fops);
+ *
+ * When a file needs to be created, this callback will be called with
+ * name = the name of the file being created (so that the same callback
+ * may be used for multiple files).
+ * mode = a place to set the file's mode
+ * data = A pointer to @data, and the callback may replace it, which will
+ * cause the file created to pass the new data to the open() call.
+ * fops = the fops to use for the created file.
*/
-static struct eventfs_file *eventfs_prepare_ef(const char *name, umode_t mode,
- const struct file_operations *fop,
- const struct inode_operations *iop,
- void *data)
+struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode *parent,
+ const struct eventfs_entry *entries,
+ int size, void *data)
{
- struct eventfs_file *ef;
+ struct eventfs_inode *ei;
- ef = kzalloc(sizeof(*ef), GFP_KERNEL);
- if (!ef)
+ if (!parent)
+ return ERR_PTR(-EINVAL);
+
+ ei = kzalloc(sizeof(*ei), GFP_KERNEL);
+ if (!ei)
return ERR_PTR(-ENOMEM);
- ef->name = kstrdup(name, GFP_KERNEL);
- if (!ef->name) {
- kfree(ef);
+ ei->name = kstrdup_const(name, GFP_KERNEL);
+ if (!ei->name) {
+ kfree(ei);
return ERR_PTR(-ENOMEM);
}
- if (S_ISDIR(mode)) {
- ef->ei = kzalloc(sizeof(*ef->ei), GFP_KERNEL);
- if (!ef->ei) {
- kfree(ef->name);
- kfree(ef);
+ if (size) {
+ ei->d_children = kzalloc(sizeof(*ei->d_children) * size, GFP_KERNEL);
+ if (!ei->d_children) {
+ kfree_const(ei->name);
+ kfree(ei);
return ERR_PTR(-ENOMEM);
}
- INIT_LIST_HEAD(&ef->ei->e_top_files);
- } else {
- ef->ei = NULL;
}
- ef->iop = iop;
- ef->fop = fop;
- ef->mode = mode;
- ef->data = data;
- return ef;
+ ei->entries = entries;
+ ei->nr_entries = size;
+ ei->data = data;
+ INIT_LIST_HEAD(&ei->children);
+
+ mutex_lock(&eventfs_mutex);
+ list_add_tail(&ei->list, &parent->children);
+ ei->d_parent = parent->dentry;
+ mutex_unlock(&eventfs_mutex);
+
+ return ei;
}
/**
- * eventfs_create_events_dir - create the trace event structure
- * @name: the name of the directory to create.
- * @parent: parent dentry for this file. This should be a directory dentry
- * if set. If this parameter is NULL, then the directory will be
- * created in the root of the tracefs filesystem.
+ * eventfs_create_events_dir - create the top level events directory
+ * @name: The name of the top level directory to create.
+ * @parent: Parent dentry for this file in the tracefs directory.
+ * @entries: A list of entries that represent the files under this directory
+ * @size: The number of @entries
+ * @data: The default data to pass to the files (an entry may override it).
*
* This function creates the top of the trace event directory.
*/
-struct dentry *eventfs_create_events_dir(const char *name,
- struct dentry *parent)
+struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry *parent,
+ const struct eventfs_entry *entries,
+ int size, void *data)
{
struct dentry *dentry = tracefs_start_creating(name, parent);
struct eventfs_inode *ei;
@@ -581,19 +731,32 @@ struct dentry *eventfs_create_events_dir(const char *name,
return NULL;
if (IS_ERR(dentry))
- return dentry;
+ return (struct eventfs_inode *)dentry;
ei = kzalloc(sizeof(*ei), GFP_KERNEL);
if (!ei)
- return ERR_PTR(-ENOMEM);
+ goto fail;
+
inode = tracefs_get_inode(dentry->d_sb);
- if (unlikely(!inode)) {
- kfree(ei);
- tracefs_failed_creating(dentry);
- return ERR_PTR(-ENOMEM);
+ if (unlikely(!inode))
+ goto fail;
+
+ if (size) {
+ ei->d_children = kzalloc(sizeof(*ei->d_children) * size, GFP_KERNEL);
+ if (!ei->d_children)
+ goto fail;
}
- INIT_LIST_HEAD(&ei->e_top_files);
+ ei->dentry = dentry;
+ ei->entries = entries;
+ ei->nr_entries = size;
+ ei->data = data;
+ ei->name = kstrdup_const(name, GFP_KERNEL);
+ if (!ei->name)
+ goto fail;
+
+ INIT_LIST_HEAD(&ei->children);
+ INIT_LIST_HEAD(&ei->list);
ti = get_tracefs(inode);
ti->flags |= TRACEFS_EVENT_INODE | TRACEFS_EVENT_TOP_INODE;
@@ -608,193 +771,41 @@ struct dentry *eventfs_create_events_dir(const char *name,
d_instantiate(dentry, inode);
inc_nlink(dentry->d_parent->d_inode);
fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
- return tracefs_end_creating(dentry);
-}
+ tracefs_end_creating(dentry);
-/**
- * eventfs_add_subsystem_dir - add eventfs subsystem_dir to list to create later
- * @name: the name of the file to create.
- * @parent: parent dentry for this dir.
- *
- * This function adds eventfs subsystem dir to list.
- * And all these dirs are created on the fly when they are looked up,
- * and the dentry and inodes will be removed when they are done.
- */
-struct eventfs_file *eventfs_add_subsystem_dir(const char *name,
- struct dentry *parent)
-{
- struct tracefs_inode *ti_parent;
- struct eventfs_inode *ei_parent;
- struct eventfs_file *ef;
+ /* Will call dput when the directory is removed */
+ dget(dentry);
- if (security_locked_down(LOCKDOWN_TRACEFS))
- return NULL;
-
- if (!parent)
- return ERR_PTR(-EINVAL);
-
- ti_parent = get_tracefs(parent->d_inode);
- ei_parent = ti_parent->private;
+ return ei;
- ef = eventfs_prepare_ef(name, S_IFDIR, NULL, NULL, NULL);
- if (IS_ERR(ef))
- return ef;
-
- mutex_lock(&eventfs_mutex);
- list_add_tail(&ef->list, &ei_parent->e_top_files);
- ef->d_parent = parent;
- mutex_unlock(&eventfs_mutex);
- return ef;
+ fail:
+ kfree(ei->d_children);
+ kfree(ei);
+ tracefs_failed_creating(dentry);
+ return ERR_PTR(-ENOMEM);
}
-/**
- * eventfs_add_dir - add eventfs dir to list to create later
- * @name: the name of the file to create.
- * @ef_parent: parent eventfs_file for this dir.
- *
- * This function adds eventfs dir to list.
- * And all these dirs are created on the fly when they are looked up,
- * and the dentry and inodes will be removed when they are done.
- */
-struct eventfs_file *eventfs_add_dir(const char *name,
- struct eventfs_file *ef_parent)
+static void free_ei(struct rcu_head *head)
{
- struct eventfs_file *ef;
-
- if (security_locked_down(LOCKDOWN_TRACEFS))
- return NULL;
+ struct eventfs_inode *ei = container_of(head, struct eventfs_inode, rcu);
- if (!ef_parent)
- return ERR_PTR(-EINVAL);
-
- ef = eventfs_prepare_ef(name, S_IFDIR, NULL, NULL, NULL);
- if (IS_ERR(ef))
- return ef;
-
- mutex_lock(&eventfs_mutex);
- list_add_tail(&ef->list, &ef_parent->ei->e_top_files);
- ef->d_parent = ef_parent->dentry;
- mutex_unlock(&eventfs_mutex);
- return ef;
-}
-
-/**
- * eventfs_add_events_file - add the data needed to create a file for later reference
- * @name: the name of the file to create.
- * @mode: the permission that the file should have.
- * @parent: parent dentry for this file.
- * @data: something that the caller will want to get to later on.
- * @fop: struct file_operations that should be used for this file.
- *
- * This function is used to add the information needed to create a
- * dentry/inode within the top level events directory. The file created
- * will have the @mode permissions. The @data will be used to fill the
- * inode.i_private when the open() call is done. The dentry and inodes are
- * all created when they are referenced, and removed when they are no
- * longer referenced.
- */
-int eventfs_add_events_file(const char *name, umode_t mode,
- struct dentry *parent, void *data,
- const struct file_operations *fop)
-{
- struct tracefs_inode *ti;
- struct eventfs_inode *ei;
- struct eventfs_file *ef;
-
- if (security_locked_down(LOCKDOWN_TRACEFS))
- return -ENODEV;
-
- if (!parent)
- return -EINVAL;
-
- if (!(mode & S_IFMT))
- mode |= S_IFREG;
-
- if (!parent->d_inode)
- return -EINVAL;
-
- ti = get_tracefs(parent->d_inode);
- if (!(ti->flags & TRACEFS_EVENT_INODE))
- return -EINVAL;
-
- ei = ti->private;
- ef = eventfs_prepare_ef(name, mode, fop, NULL, data);
-
- if (IS_ERR(ef))
- return -ENOMEM;
-
- mutex_lock(&eventfs_mutex);
- list_add_tail(&ef->list, &ei->e_top_files);
- ef->d_parent = parent;
- mutex_unlock(&eventfs_mutex);
- return 0;
-}
-
-/**
- * eventfs_add_file - add eventfs file to list to create later
- * @name: the name of the file to create.
- * @mode: the permission that the file should have.
- * @ef_parent: parent eventfs_file for this file.
- * @data: something that the caller will want to get to later on.
- * @fop: struct file_operations that should be used for this file.
- *
- * This function is used to add the information needed to create a
- * file within a subdirectory of the events directory. The file created
- * will have the @mode permissions. The @data will be used to fill the
- * inode.i_private when the open() call is done. The dentry and inodes are
- * all created when they are referenced, and removed when they are no
- * longer referenced.
- */
-int eventfs_add_file(const char *name, umode_t mode,
- struct eventfs_file *ef_parent,
- void *data,
- const struct file_operations *fop)
-{
- struct eventfs_file *ef;
-
- if (security_locked_down(LOCKDOWN_TRACEFS))
- return -ENODEV;
-
- if (!ef_parent)
- return -EINVAL;
-
- if (!(mode & S_IFMT))
- mode |= S_IFREG;
-
- ef = eventfs_prepare_ef(name, mode, fop, NULL, data);
- if (IS_ERR(ef))
- return -ENOMEM;
-
- mutex_lock(&eventfs_mutex);
- list_add_tail(&ef->list, &ef_parent->ei->e_top_files);
- ef->d_parent = ef_parent->dentry;
- mutex_unlock(&eventfs_mutex);
- return 0;
-}
-
-static void free_ef(struct rcu_head *head)
-{
- struct eventfs_file *ef = container_of(head, struct eventfs_file, rcu);
-
- kfree(ef->name);
- kfree(ef->ei);
- kfree(ef);
+ kfree_const(ei->name);
+ kfree(ei->d_children);
+ kfree(ei);
}
/**
* eventfs_remove_rec - remove eventfs dir or file from list
- * @ef: eventfs_file to be removed.
- * @head: to create list of eventfs_file to be deleted
- * @level: to check recursion depth
+ * @ei: eventfs_inode to be removed.
*
- * The helper function eventfs_remove_rec() is used to clean up and free the
- * associated data from eventfs for both of the added functions.
+ * This function recursively remove eventfs_inode which
+ * contains info of file or dir.
*/
-static void eventfs_remove_rec(struct eventfs_file *ef, struct list_head *head, int level)
+static void eventfs_remove_rec(struct eventfs_inode *ei, struct list_head *head, int level)
{
- struct eventfs_file *ef_child;
+ struct eventfs_inode *ei_child;
- if (!ef)
+ if (!ei)
return;
/*
* Check recursion depth. It should never be greater than 3:
@@ -806,62 +817,68 @@ static void eventfs_remove_rec(struct eventfs_file *ef, struct list_head *head,
if (WARN_ON_ONCE(level > 3))
return;
- if (ef->ei) {
- /* search for nested folders or files */
- list_for_each_entry_srcu(ef_child, &ef->ei->e_top_files, list,
- lockdep_is_held(&eventfs_mutex)) {
- eventfs_remove_rec(ef_child, head, level + 1);
- }
+ /* search for nested folders or files */
+ list_for_each_entry_srcu(ei_child, &ei->children, list,
+ lockdep_is_held(&eventfs_mutex)) {
+ eventfs_remove_rec(ei_child, head, level + 1);
}
- list_del_rcu(&ef->list);
- list_add_tail(&ef->del_list, head);
+ list_del_rcu(&ei->list);
+ list_add_tail(&ei->del_list, head);
}
+static void unhook_dentry(struct dentry **dentry, struct dentry **list)
+{
+ if (*dentry) {
+ unsigned long ptr = (unsigned long)*list;
+
+ /* Keep the dentry from being freed yet */
+ dget(*dentry);
+
+ /*
+ * Paranoid: The dget() above should prevent the dentry
+ * from being freed and calling eventfs_set_ei_status_free().
+ * But just in case, set the link list LSB pointer to 1
+ * and have eventfs_set_ei_status_free() check that to
+ * make sure that if it does happen, it will not think
+ * the d_fsdata is an eventfs_inode.
+ *
+ * For this to work, no eventfs_inode should be allocated
+ * on a odd space, as the ef should always be allocated
+ * to be at least word aligned. Check for that too.
+ */
+ WARN_ON_ONCE(ptr & 1);
+
+ (*dentry)->d_fsdata = (void *)(ptr | 1);
+ *list = *dentry;
+ *dentry = NULL;
+ }
+}
/**
* eventfs_remove - remove eventfs dir or file from list
- * @ef: eventfs_file to be removed.
+ * @ei: eventfs_inode to be removed.
*
* This function acquire the eventfs_mutex lock and call eventfs_remove_rec()
*/
-void eventfs_remove(struct eventfs_file *ef)
+void eventfs_remove_dir(struct eventfs_inode *ei)
{
- struct eventfs_file *tmp;
- LIST_HEAD(ef_del_list);
+ struct eventfs_inode *tmp;
+ LIST_HEAD(ei_del_list);
struct dentry *dentry_list = NULL;
struct dentry *dentry;
+ int i;
- if (!ef)
+ if (!ei)
return;
mutex_lock(&eventfs_mutex);
- eventfs_remove_rec(ef, &ef_del_list, 0);
- list_for_each_entry_safe(ef, tmp, &ef_del_list, del_list) {
- if (ef->dentry) {
- unsigned long ptr = (unsigned long)dentry_list;
-
- /* Keep the dentry from being freed yet */
- dget(ef->dentry);
-
- /*
- * Paranoid: The dget() above should prevent the dentry
- * from being freed and calling eventfs_set_ef_status_free().
- * But just in case, set the link list LSB pointer to 1
- * and have eventfs_set_ef_status_free() check that to
- * make sure that if it does happen, it will not think
- * the d_fsdata is an event_file.
- *
- * For this to work, no event_file should be allocated
- * on a odd space, as the ef should always be allocated
- * to be at least word aligned. Check for that too.
- */
- WARN_ON_ONCE(ptr & 1);
-
- ef->dentry->d_fsdata = (void *)(ptr | 1);
- dentry_list = ef->dentry;
- ef->dentry = NULL;
- }
- call_srcu(&eventfs_srcu, &ef->rcu, free_ef);
+ eventfs_remove_rec(ei, &ei_del_list, 0);
+
+ list_for_each_entry_safe(ei, tmp, &ei_del_list, del_list) {
+ for (i = 0; i < ei->nr_entries; i++)
+ unhook_dentry(&ei->d_children[i], &dentry_list);
+ unhook_dentry(&ei->dentry, &dentry_list);
+ call_srcu(&eventfs_srcu, &ei->rcu, free_ei);
}
mutex_unlock(&eventfs_mutex);
@@ -876,8 +893,8 @@ void eventfs_remove(struct eventfs_file *ef)
mutex_lock(&eventfs_mutex);
/* dentry should now have at least a single reference */
WARN_ONCE((int)d_count(dentry) < 1,
- "dentry %p less than one reference (%d) after invalidate\n",
- dentry, d_count(dentry));
+ "dentry %px (%s) less than one reference (%d) after invalidate\n",
+ dentry, dentry->d_name.name, d_count(dentry));
mutex_unlock(&eventfs_mutex);
dput(dentry);
}
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index 891653ba9cf3..34ffb2f8114e 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -385,7 +385,7 @@ static void tracefs_dentry_iput(struct dentry *dentry, struct inode *inode)
ti = get_tracefs(inode);
if (ti && ti->flags & TRACEFS_EVENT_INODE)
- eventfs_set_ef_status_free(ti, dentry);
+ eventfs_set_ei_status_free(ti, dentry);
iput(inode);
}
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 4f2e49e2197b..298d3ecaf621 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -13,6 +13,41 @@ struct tracefs_inode {
struct inode vfs_inode;
};
+/*
+ * struct eventfs_inode - hold the properties of the eventfs directories.
+ * @list: link list into the parent directory
+ * @entries: the array of entries representing the files in the directory
+ * @name: the name of the directory to create
+ * @children: link list into the child eventfs_inode
+ * @dentry: the dentry of the directory
+ * @d_parent: pointer to the parent's dentry
+ * @d_children: The array of dentries to represent the files when created
+ * @data: The private data to pass to the callbacks
+ * @nr_entries: The number of items in @entries
+ */
+struct eventfs_inode {
+ struct list_head list;
+ const struct eventfs_entry *entries;
+ const char *name;
+ struct list_head children;
+ struct dentry *dentry;
+ struct dentry *d_parent;
+ struct dentry **d_children;
+ void *data;
+ /*
+ * Union - used for deletion
+ * @del_list: list of eventfs_inode to delete
+ * @rcu: eventfs_indoe to delete in RCU
+ * @is_freed: node is freed if one of the above is set
+ */
+ union {
+ struct list_head del_list;
+ struct rcu_head rcu;
+ unsigned long is_freed;
+ };
+ int nr_entries;
+};
+
static inline struct tracefs_inode *get_tracefs(const struct inode *inode)
{
return container_of(inode, struct tracefs_inode, vfs_inode);
@@ -25,6 +60,6 @@ struct inode *tracefs_get_inode(struct super_block *sb);
struct dentry *eventfs_start_creating(const char *name, struct dentry *parent);
struct dentry *eventfs_failed_creating(struct dentry *dentry);
struct dentry *eventfs_end_creating(struct dentry *dentry);
-void eventfs_set_ef_status_free(struct tracefs_inode *ti, struct dentry *dentry);
+void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry);
#endif /* _TRACEFS_INTERNAL_H */
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index cf9f0c61796e..696f8dc4aa53 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -652,7 +652,7 @@ struct trace_event_file {
struct list_head list;
struct trace_event_call *event_call;
struct event_filter __rcu *filter;
- struct eventfs_file *ef;
+ struct eventfs_inode *ei;
struct trace_array *tr;
struct trace_subsystem_dir *system;
struct list_head triggers;
diff --git a/include/linux/tracefs.h b/include/linux/tracefs.h
index 009072792fa3..0c39704455d9 100644
--- a/include/linux/tracefs.h
+++ b/include/linux/tracefs.h
@@ -23,26 +23,25 @@ struct file_operations;
struct eventfs_file;
-struct dentry *eventfs_create_events_dir(const char *name,
- struct dentry *parent);
+typedef int (*eventfs_callback)(const char *name, umode_t *mode, void **data,
+ const struct file_operations **fops);
-struct eventfs_file *eventfs_add_subsystem_dir(const char *name,
- struct dentry *parent);
+struct eventfs_entry {
+ const char *name;
+ eventfs_callback callback;
+};
-struct eventfs_file *eventfs_add_dir(const char *name,
- struct eventfs_file *ef_parent);
+struct eventfs_inode;
-int eventfs_add_file(const char *name, umode_t mode,
- struct eventfs_file *ef_parent, void *data,
- const struct file_operations *fops);
+struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry *parent,
+ const struct eventfs_entry *entries,
+ int size, void *data);
-int eventfs_add_events_file(const char *name, umode_t mode,
- struct dentry *parent, void *data,
- const struct file_operations *fops);
+struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode *parent,
+ const struct eventfs_entry *entries,
+ int size, void *data);
-void eventfs_remove(struct eventfs_file *ef);
-
-void eventfs_remove_events_dir(struct dentry *dentry);
+void eventfs_remove_dir(struct eventfs_inode *ei);
struct dentry *tracefs_create_file(const char *name, umode_t mode,
struct dentry *parent, void *data,
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index fc00356a5a0a..33a6ea7145c2 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -9758,7 +9758,6 @@ static __init void create_trace_instances(struct dentry *d_tracer)
static void
init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
{
- struct trace_event_file *file;
int cpu;
trace_create_file("available_tracers", TRACE_MODE_READ, d_tracer,
@@ -9791,11 +9790,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
trace_create_file("trace_marker", 0220, d_tracer,
tr, &tracing_mark_fops);
- file = __find_event_file(tr, "ftrace", "print");
- if (file && file->ef)
- eventfs_add_file("trigger", TRACE_MODE_WRITE, file->ef,
- file, &event_trigger_fops);
- tr->trace_marker_file = file;
+ tr->trace_marker_file = __find_event_file(tr, "ftrace", "print");
trace_create_file("trace_marker_raw", 0220, d_tracer,
tr, &tracing_mark_raw_fops);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 51c0a970339e..02b727a54648 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -381,7 +381,7 @@ struct trace_array {
struct dentry *dir;
struct dentry *options;
struct dentry *percpu_dir;
- struct dentry *event_dir;
+ struct eventfs_inode *event_dir;
struct trace_options *topts;
struct list_head systems;
struct list_head events;
@@ -1345,7 +1345,7 @@ struct trace_subsystem_dir {
struct list_head list;
struct event_subsystem *subsystem;
struct trace_array *tr;
- struct eventfs_file *ef;
+ struct eventfs_inode *ei;
int ref_count;
int nr_events;
};
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 82cb22ad6d61..6595317c3830 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -984,7 +984,7 @@ static void remove_subsystem(struct trace_subsystem_dir *dir)
return;
if (!--dir->nr_events) {
- eventfs_remove(dir->ef);
+ eventfs_remove_dir(dir->ei);
list_del(&dir->list);
__put_system_dir(dir);
}
@@ -1013,7 +1013,7 @@ void event_file_put(struct trace_event_file *file)
static void remove_event_file_dir(struct trace_event_file *file)
{
- eventfs_remove(file->ef);
+ eventfs_remove_dir(file->ei);
list_del(&file->list);
remove_subsystem(file->system);
free_event_filter(file->filter);
@@ -2302,14 +2302,40 @@ create_new_subsystem(const char *name)
return NULL;
}
-static struct eventfs_file *
+int system_callback(const char *name, umode_t *mode, void **data,
+ const struct file_operations **fops)
+{
+ if (strcmp(name, "filter") == 0)
+ *fops = &ftrace_subsystem_filter_fops;
+
+ else if (strcmp(name, "enable") == 0)
+ *fops = &ftrace_system_enable_fops;
+
+ else
+ return 0;
+
+ *mode = TRACE_MODE_WRITE;
+ return 1;
+}
+
+static struct eventfs_inode *
event_subsystem_dir(struct trace_array *tr, const char *name,
- struct trace_event_file *file, struct dentry *parent)
+ struct trace_event_file *file, struct eventfs_inode *parent)
{
struct event_subsystem *system, *iter;
struct trace_subsystem_dir *dir;
- struct eventfs_file *ef;
- int res;
+ struct eventfs_inode *ei;
+ int nr_entries;
+ static struct eventfs_entry system_entries[] = {
+ {
+ .name = "filter",
+ .callback = system_callback,
+ },
+ {
+ .name = "enable",
+ .callback = system_callback,
+ }
+ };
/* First see if we did not already create this dir */
list_for_each_entry(dir, &tr->systems, list) {
@@ -2317,7 +2343,7 @@ event_subsystem_dir(struct trace_array *tr, const char *name,
if (strcmp(system->name, name) == 0) {
dir->nr_events++;
file->system = dir;
- return dir->ef;
+ return dir->ei;
}
}
@@ -2341,39 +2367,29 @@ event_subsystem_dir(struct trace_array *tr, const char *name,
} else
__get_system(system);
- ef = eventfs_add_subsystem_dir(name, parent);
- if (IS_ERR(ef)) {
+ /* ftrace only has directories no files */
+ if (strcmp(name, "ftrace") == 0)
+ nr_entries = 0;
+ else
+ nr_entries = ARRAY_SIZE(system_entries);
+
+ ei = eventfs_create_dir(name, parent, system_entries, nr_entries, dir);
+ if (!ei) {
pr_warn("Failed to create system directory %s\n", name);
__put_system(system);
goto out_free;
}
- dir->ef = ef;
+ dir->ei = ei;
dir->tr = tr;
dir->ref_count = 1;
dir->nr_events = 1;
dir->subsystem = system;
file->system = dir;
- /* the ftrace system is special, do not create enable or filter files */
- if (strcmp(name, "ftrace") != 0) {
-
- res = eventfs_add_file("filter", TRACE_MODE_WRITE,
- dir->ef, dir,
- &ftrace_subsystem_filter_fops);
- if (res) {
- kfree(system->filter);
- system->filter = NULL;
- pr_warn("Could not create tracefs '%s/filter' entry\n", name);
- }
-
- eventfs_add_file("enable", TRACE_MODE_WRITE, dir->ef, dir,
- &ftrace_system_enable_fops);
- }
-
list_add(&dir->list, &tr->systems);
- return dir->ef;
+ return dir->ei;
out_free:
kfree(dir);
@@ -2422,15 +2438,134 @@ event_define_fields(struct trace_event_call *call)
return ret;
}
+static int event_callback(const char *name, umode_t *mode, void **data,
+ const struct file_operations **fops)
+{
+ struct trace_event_file *file = *data;
+ struct trace_event_call *call = file->event_call;
+
+ if (strcmp(name, "format") == 0) {
+ *mode = TRACE_MODE_READ;
+ *fops = &ftrace_event_format_fops;
+ *data = call;
+ return 1;
+ }
+
+ /*
+ * Only event directories that can be enabled should have
+ * triggers or filters, with the exception of the "print"
+ * event that can have a "trigger" file.
+ */
+ if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
+ if (call->class->reg && strcmp(name, "enable") == 0) {
+ *mode = TRACE_MODE_WRITE;
+ *fops = &ftrace_enable_fops;
+ return 1;
+ }
+
+ if (strcmp(name, "filter") == 0) {
+ *mode = TRACE_MODE_WRITE;
+ *fops = &ftrace_event_filter_fops;
+ return 1;
+ }
+ }
+
+ if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
+ strcmp(trace_event_name(call), "print") == 0) {
+ if (strcmp(name, "trigger") == 0) {
+ *mode = TRACE_MODE_WRITE;
+ *fops = &event_trigger_fops;
+ return 1;
+ }
+ }
+
+#ifdef CONFIG_PERF_EVENTS
+ if (call->event.type && call->class->reg &&
+ strcmp(name, "id") == 0) {
+ *mode = TRACE_MODE_READ;
+ *data = (void *)(long)call->event.type;
+ *fops = &ftrace_event_id_fops;
+ return 1;
+ }
+#endif
+
+#ifdef CONFIG_HIST_TRIGGERS
+ if (strcmp(name, "hist") == 0) {
+ *mode = TRACE_MODE_READ;
+ *fops = &event_hist_fops;
+ return 1;
+ }
+#endif
+#ifdef CONFIG_HIST_TRIGGERS_DEBUG
+ if (strcmp(name, "hist_debug") == 0) {
+ *mode = TRACE_MODE_READ;
+ *fops = &event_hist_debug_fops;
+ return 1;
+ }
+#endif
+#ifdef CONFIG_TRACE_EVENT_INJECT
+ if (call->event.type && call->class->reg &&
+ strcmp(name, "inject") == 0) {
+ *mode = 0200;
+ *fops = &event_inject_fops;
+ return 1;
+ }
+#endif
+ return 0;
+}
+
static int
-event_create_dir(struct dentry *parent, struct trace_event_file *file)
+event_create_dir(struct eventfs_inode *parent, struct trace_event_file *file)
{
struct trace_event_call *call = file->event_call;
- struct eventfs_file *ef_subsystem = NULL;
struct trace_array *tr = file->tr;
- struct eventfs_file *ef;
+ struct eventfs_inode *e_events;
+ struct eventfs_inode *ei;
const char *name;
+ int nr_entries;
int ret;
+ static struct eventfs_entry event_entries[] = {
+ {
+ .name = "enable",
+ .callback = event_callback,
+ },
+ {
+ .name = "filter",
+ .callback = event_callback,
+ },
+ {
+ .name = "trigger",
+ .callback = event_callback,
+ },
+ {
+ .name = "format",
+ .callback = event_callback,
+ },
+#ifdef CONFIG_PERF_EVENTS
+ {
+ .name = "id",
+ .callback = event_callback,
+ },
+#endif
+#ifdef CONFIG_HIST_TRIGGERS
+ {
+ .name = "hist",
+ .callback = event_callback,
+ },
+#endif
+#ifdef CONFIG_HIST_TRIGGERS_DEBUG
+ {
+ .name = "hist_debug",
+ .callback = event_callback,
+ },
+#endif
+#ifdef CONFIG_TRACE_EVENT_INJECT
+ {
+ .name = "inject",
+ .callback = event_callback,
+ },
+#endif
+ };
/*
* If the trace point header did not define TRACE_SYSTEM
@@ -2440,29 +2575,20 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file)
if (WARN_ON_ONCE(strcmp(call->class->system, TRACE_SYSTEM) == 0))
return -ENODEV;
- ef_subsystem = event_subsystem_dir(tr, call->class->system, file, parent);
- if (!ef_subsystem)
+ e_events = event_subsystem_dir(tr, call->class->system, file, parent);
+ if (!e_events)
return -ENOMEM;
+ nr_entries = ARRAY_SIZE(event_entries);
+
name = trace_event_name(call);
- ef = eventfs_add_dir(name, ef_subsystem);
- if (IS_ERR(ef)) {
+ ei = eventfs_create_dir(name, e_events, event_entries, nr_entries, file);
+ if (IS_ERR(ei)) {
pr_warn("Could not create tracefs '%s' directory\n", name);
return -1;
}
- file->ef = ef;
-
- if (call->class->reg && !(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
- eventfs_add_file("enable", TRACE_MODE_WRITE, file->ef, file,
- &ftrace_enable_fops);
-
-#ifdef CONFIG_PERF_EVENTS
- if (call->event.type && call->class->reg)
- eventfs_add_file("id", TRACE_MODE_READ, file->ef,
- (void *)(long)call->event.type,
- &ftrace_event_id_fops);
-#endif
+ file->ei = ei;
ret = event_define_fields(call);
if (ret < 0) {
@@ -2470,35 +2596,6 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file)
return ret;
}
- /*
- * Only event directories that can be enabled should have
- * triggers or filters.
- */
- if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
- eventfs_add_file("filter", TRACE_MODE_WRITE, file->ef,
- file, &ftrace_event_filter_fops);
-
- eventfs_add_file("trigger", TRACE_MODE_WRITE, file->ef,
- file, &event_trigger_fops);
- }
-
-#ifdef CONFIG_HIST_TRIGGERS
- eventfs_add_file("hist", TRACE_MODE_READ, file->ef, file,
- &event_hist_fops);
-#endif
-#ifdef CONFIG_HIST_TRIGGERS_DEBUG
- eventfs_add_file("hist_debug", TRACE_MODE_READ, file->ef, file,
- &event_hist_debug_fops);
-#endif
- eventfs_add_file("format", TRACE_MODE_READ, file->ef, call,
- &ftrace_event_format_fops);
-
-#ifdef CONFIG_TRACE_EVENT_INJECT
- if (call->event.type && call->class->reg)
- eventfs_add_file("inject", 0200, file->ef, file,
- &event_inject_fops);
-#endif
-
return 0;
}
@@ -3644,30 +3741,65 @@ static __init int setup_trace_event(char *str)
}
__setup("trace_event=", setup_trace_event);
+static int events_callback(const char *name, umode_t *mode, void **data,
+ const struct file_operations **fops)
+{
+ if (strcmp(name, "enable") == 0) {
+ *mode = TRACE_MODE_WRITE;
+ *fops = &ftrace_tr_enable_fops;
+ return 1;
+ }
+
+ if (strcmp(name, "header_page") == 0)
+ *data = ring_buffer_print_page_header;
+
+ else if (strcmp(name, "header_event") == 0)
+ *data = ring_buffer_print_entry_header;
+
+ else
+ return 0;
+
+ *mode = TRACE_MODE_READ;
+ *fops = &ftrace_show_header_fops;
+ return 1;
+}
+
/* Expects to have event_mutex held when called */
static int
create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
{
- struct dentry *d_events;
+ struct eventfs_inode *e_events;
struct dentry *entry;
- int error = 0;
+ int nr_entries;
+ static struct eventfs_entry events_entries[] = {
+ {
+ .name = "enable",
+ .callback = events_callback,
+ },
+ {
+ .name = "header_page",
+ .callback = events_callback,
+ },
+ {
+ .name = "header_event",
+ .callback = events_callback,
+ },
+ };
entry = trace_create_file("set_event", TRACE_MODE_WRITE, parent,
tr, &ftrace_set_event_fops);
if (!entry)
return -ENOMEM;
- d_events = eventfs_create_events_dir("events", parent);
- if (IS_ERR(d_events)) {
+ nr_entries = ARRAY_SIZE(events_entries);
+
+ e_events = eventfs_create_events_dir("events", parent, events_entries,
+ nr_entries, tr);
+ if (IS_ERR(e_events)) {
pr_warn("Could not create tracefs 'events' directory\n");
return -ENOMEM;
}
- error = eventfs_add_events_file("enable", TRACE_MODE_WRITE, d_events,
- tr, &ftrace_tr_enable_fops);
- if (error)
- return -ENOMEM;
-
/* There are not as crucial, just warn if they are not created */
trace_create_file("set_event_pid", TRACE_MODE_WRITE, parent,
@@ -3677,16 +3809,7 @@ create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
TRACE_MODE_WRITE, parent, tr,
&ftrace_set_event_notrace_pid_fops);
- /* ring buffer internal formats */
- eventfs_add_events_file("header_page", TRACE_MODE_READ, d_events,
- ring_buffer_print_page_header,
- &ftrace_show_header_fops);
-
- eventfs_add_events_file("header_event", TRACE_MODE_READ, d_events,
- ring_buffer_print_entry_header,
- &ftrace_show_header_fops);
-
- tr->event_dir = d_events;
+ tr->event_dir = e_events;
return 0;
}
@@ -3770,7 +3893,7 @@ int event_trace_del_tracer(struct trace_array *tr)
down_write(&trace_event_sem);
__trace_remove_event_dirs(tr);
- eventfs_remove_events_dir(tr->event_dir);
+ eventfs_remove_dir(tr->event_dir);
up_write(&trace_event_sem);
tr->event_dir = NULL;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 08/57] eventfs: Use eventfs_remove_events_dir()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (6 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 07/57] eventfs: Remove eventfs_file and just use eventfs_inode Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 09/57] eventfs: Use ERR_CAST() in eventfs_create_events_dir() Steven Rostedt
` (49 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
kernel test robot
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The update to removing the eventfs_file changed the way the events top
level directory was handled. Instead of returning a dentry, it now returns
the eventfs_inode. In this changed, the removing of the events top level
directory is not much different than removing any of the other
directories. Because of this, the removal just called eventfs_remove_dir()
instead of eventfs_remove_events_dir().
Although eventfs_remove_dir() does the clean up, it misses out on the
dget() of the ei->dentry done in eventfs_create_events_dir(). It makes
more sense to match eventfs_create_events_dir() with a specific function
eventfs_remove_events_dir() and this specific function can then perform
the dput() to the dentry that had the dget() when it was created.
Fixes: 5790b1fb3d67 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202310051743.y9EobbUr-lkp@intel.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 2819f23ac12ce93ff79ca7a54597df9a4a1f6331)
---
fs/tracefs/event_inode.c | 19 +++++++------------
include/linux/tracefs.h | 1 +
kernel/trace/trace_events.c | 2 +-
3 files changed, 9 insertions(+), 13 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index eab18b157ef5..1ccd100bc565 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -901,22 +901,17 @@ void eventfs_remove_dir(struct eventfs_inode *ei)
}
/**
- * eventfs_remove_events_dir - remove eventfs dir or file from list
- * @dentry: events's dentry to be removed.
+ * eventfs_remove_events_dir - remove the top level eventfs directory
+ * @ei: the event_inode returned by eventfs_create_events_dir().
*
- * This function remove events main directory
+ * This function removes the events main directory
*/
-void eventfs_remove_events_dir(struct dentry *dentry)
+void eventfs_remove_events_dir(struct eventfs_inode *ei)
{
- struct tracefs_inode *ti;
-
- if (!dentry || !dentry->d_inode)
- return;
+ struct dentry *dentry = ei->dentry;
- ti = get_tracefs(dentry->d_inode);
- if (!ti || !(ti->flags & TRACEFS_EVENT_INODE))
- return;
+ eventfs_remove_dir(ei);
- d_invalidate(dentry);
+ /* Matches the dget() from eventfs_create_events_dir() */
dput(dentry);
}
diff --git a/include/linux/tracefs.h b/include/linux/tracefs.h
index 0c39704455d9..13359b1a35d1 100644
--- a/include/linux/tracefs.h
+++ b/include/linux/tracefs.h
@@ -41,6 +41,7 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode
const struct eventfs_entry *entries,
int size, void *data);
+void eventfs_remove_events_dir(struct eventfs_inode *ei);
void eventfs_remove_dir(struct eventfs_inode *ei);
struct dentry *tracefs_create_file(const char *name, umode_t mode,
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 6595317c3830..697163f8f670 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -3893,7 +3893,7 @@ int event_trace_del_tracer(struct trace_array *tr)
down_write(&trace_event_sem);
__trace_remove_event_dirs(tr);
- eventfs_remove_dir(tr->event_dir);
+ eventfs_remove_events_dir(tr->event_dir);
up_write(&trace_event_sem);
tr->event_dir = NULL;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 09/57] eventfs: Use ERR_CAST() in eventfs_create_events_dir()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (7 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 08/57] eventfs: Use eventfs_remove_events_dir() Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 10/57] eventfs: Fix failure path " Steven Rostedt
` (48 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Kees Cook,
Nathan Chancellor
From: Nathan Chancellor <nathan@kernel.org>
When building with clang and CONFIG_RANDSTRUCT_FULL=y, there is an error
due to a cast in eventfs_create_events_dir():
fs/tracefs/event_inode.c:734:10: error: casting from randomized structure pointer type 'struct dentry *' to 'struct eventfs_inode *'
734 | return (struct eventfs_inode *)dentry;
| ^
1 error generated.
Use the ERR_CAST() function to resolve the error, as it was designed for
this exact situation (casting an error pointer to another type).
Link: https://lore.kernel.org/linux-trace-kernel/20231018-ftrace-fix-clang-randstruct-v1-1-338cb214abfb@kernel.org
Closes: https://github.com/ClangBuiltLinux/linux/issues/1947
Fixes: 5790b1fb3d67 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit b8a555dc31e5aa18d976de0bc228006e398a2e7d)
---
fs/tracefs/event_inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 1ccd100bc565..9f19b6608954 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -731,7 +731,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
return NULL;
if (IS_ERR(dentry))
- return (struct eventfs_inode *)dentry;
+ return ERR_CAST(dentry);
ei = kzalloc(sizeof(*ei), GFP_KERNEL);
if (!ei)
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 10/57] eventfs: Fix failure path in eventfs_create_events_dir()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (8 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 09/57] eventfs: Use ERR_CAST() in eventfs_create_events_dir() Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 11/57] tracefs/eventfs: Modify mismatched function name Steven Rostedt
` (47 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Julia Lawall
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The failure path of allocating ei goes to a path that dereferences ei.
Add another label that skips over the ei dereferences to do the rest of
the clean up.
Link: https://lore.kernel.org/all/70e7bace-561c-95f-1117-706c2c220bc@inria.fr/
Link: https://lore.kernel.org/linux-trace-kernel/20231019204132.6662fef0@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes: 5790b1fb3d67 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: Julia Lawall <julia.lawall@inria.fr>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 7e8ad67c9b5c11e990c320ed7e7563f2301672a7)
---
fs/tracefs/event_inode.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 9f19b6608954..1885f1f1f339 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -735,7 +735,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
ei = kzalloc(sizeof(*ei), GFP_KERNEL);
if (!ei)
- goto fail;
+ goto fail_ei;
inode = tracefs_get_inode(dentry->d_sb);
if (unlikely(!inode))
@@ -781,6 +781,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
fail:
kfree(ei->d_children);
kfree(ei);
+ fail_ei:
tracefs_failed_creating(dentry);
return ERR_PTR(-ENOMEM);
}
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 11/57] tracefs/eventfs: Modify mismatched function name
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (9 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 10/57] eventfs: Fix failure path " Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 12/57] eventfs: Fix WARN_ON() in create_file_dentry() Steven Rostedt
` (46 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Abaci Robot,
Jiapeng Chong
From: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
No functional modification involved.
fs/tracefs/event_inode.c:864: warning: expecting prototype for eventfs_remove(). Prototype was for eventfs_remove_dir() instead.
Link: https://lore.kernel.org/linux-trace-kernel/20231019031353.73846-1-jiapeng.chong@linux.alibaba.com
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=6939
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 64bf2f685c795e75dd855761c75a193ee5998731)
---
fs/tracefs/event_inode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 1885f1f1f339..09ab93357957 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -856,7 +856,7 @@ static void unhook_dentry(struct dentry **dentry, struct dentry **list)
}
}
/**
- * eventfs_remove - remove eventfs dir or file from list
+ * eventfs_remove_dir - remove eventfs dir or file from list
* @ei: eventfs_inode to be removed.
*
* This function acquire the eventfs_mutex lock and call eventfs_remove_rec()
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 12/57] eventfs: Fix WARN_ON() in create_file_dentry()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (10 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 11/57] tracefs/eventfs: Modify mismatched function name Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 13/57] eventfs: Fix typo in eventfs_inode union comment Steven Rostedt
` (45 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
As the comment right above a WARN_ON() in create_file_dentry() states:
* Note, with the mutex held, the e_dentry cannot have content
* and the ei->is_freed be true at the same time.
But the WARN_ON() only has:
WARN_ON_ONCE(ei->is_free);
Where to match the comment (and what it should actually do) is:
dentry = *e_dentry;
WARN_ON_ONCE(dentry && ei->is_free)
Also in that case, set dentry to NULL (although it should never happen).
Link: https://lore.kernel.org/linux-trace-kernel/20231024123628.62b88755@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit a9de4eb15ad430fe45747c211e367da745a90093)
---
fs/tracefs/event_inode.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 09ab93357957..4d2da7480e5f 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -264,8 +264,9 @@ create_file_dentry(struct eventfs_inode *ei, struct dentry **e_dentry,
* Note, with the mutex held, the e_dentry cannot have content
* and the ei->is_freed be true at the same time.
*/
- WARN_ON_ONCE(ei->is_freed);
dentry = *e_dentry;
+ if (WARN_ON_ONCE(dentry && ei->is_freed))
+ dentry = NULL;
/* The lookup does not need to up the dentry refcount */
if (dentry && !lookup)
dget(dentry);
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 13/57] eventfs: Fix typo in eventfs_inode union comment
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (11 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 12/57] eventfs: Fix WARN_ON() in create_file_dentry() Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 14/57] eventfs: Remove extra dget() in eventfs_create_events_dir() Steven Rostedt
` (44 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
It's eventfs_inode not eventfs_indoe. There's no deer involved!
Link: https://lore.kernel.org/linux-trace-kernel/20231024131024.5634c743@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 29e06c10702e81a7d0b75020ca514d2f2962704a)
---
fs/tracefs/internal.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 298d3ecaf621..64fde9490f52 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -37,7 +37,7 @@ struct eventfs_inode {
/*
* Union - used for deletion
* @del_list: list of eventfs_inode to delete
- * @rcu: eventfs_indoe to delete in RCU
+ * @rcu: eventfs_inode to delete in RCU
* @is_freed: node is freed if one of the above is set
*/
union {
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 14/57] eventfs: Remove extra dget() in eventfs_create_events_dir()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (12 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 13/57] eventfs: Fix typo in eventfs_inode union comment Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 15/57] eventfs: Fix kerneldoc of eventfs_remove_rec() Steven Rostedt
` (43 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The creation of the top events directory does a dget() at the end of the
creation in eventfs_create_events_dir() with a comment saying the final
dput() will happen when it is removed. The problem is that a dget() is
already done on the dentry when it was created with tracefs_start_creating()!
The dget() now just causes a memory leak of that dentry.
Remove the extra dget() as the final dput() in the deletion of the events
directory actually matches the one in tracefs_start_creating().
Link: https://lore.kernel.org/linux-trace-kernel/20231031124229.4f2e3fa1@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 77bc4d4921bd3497678ba8e7f4e480de35692f05)
---
fs/tracefs/event_inode.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 4d2da7480e5f..5536860eb2ff 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -774,9 +774,6 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
tracefs_end_creating(dentry);
- /* Will call dput when the directory is removed */
- dget(dentry);
-
return ei;
fail:
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 15/57] eventfs: Fix kerneldoc of eventfs_remove_rec()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (13 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 14/57] eventfs: Remove extra dget() in eventfs_create_events_dir() Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 16/57] eventfs: Remove "is_freed" union with rcu head Steven Rostedt
` (42 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
kernel test robot
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The eventfs_remove_rec() had some missing parameters in the kerneldoc
comment above it. Also, rephrase the description a bit more to have a bit
more correct grammar.
Link: https://lore.kernel.org/linux-trace-kernel/20231030121523.0b2225a7@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode");
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202310052216.4SgqasWo-lkp@intel.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 9037caa09ed345b35325200f0e4acf5a94ae0a65)
---
fs/tracefs/event_inode.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 5536860eb2ff..9f612a8f009d 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -796,9 +796,11 @@ static void free_ei(struct rcu_head *head)
/**
* eventfs_remove_rec - remove eventfs dir or file from list
* @ei: eventfs_inode to be removed.
+ * @head: the list head to place the deleted @ei and children
+ * @level: prevent recursion from going more than 3 levels deep.
*
- * This function recursively remove eventfs_inode which
- * contains info of file or dir.
+ * This function recursively removes eventfs_inodes which
+ * contains info of files and/or directories.
*/
static void eventfs_remove_rec(struct eventfs_inode *ei, struct list_head *head, int level)
{
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 16/57] eventfs: Remove "is_freed" union with rcu head
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (14 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 15/57] eventfs: Fix kerneldoc of eventfs_remove_rec() Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 17/57] eventfs: Have a free_ei() that just frees the eventfs_inode Steven Rostedt
` (41 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Ajay Kaher
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The eventfs_inode->is_freed was a union with the rcu_head with the
assumption that when it was on the srcu list the head would contain a
pointer which would make "is_freed" true. But that was a wrong assumption
as the rcu head is a single link list where the last element is NULL.
Instead, split the nr_entries integer so that "is_freed" is one bit and
the nr_entries is the next 31 bits. As there shouldn't be more than 10
(currently there's at most 5 to 7 depending on the config), this should
not be a problem.
Link: https://lkml.kernel.org/r/20231101172649.049758712@goodmis.org
Cc: stable@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ajay Kaher <akaher@vmware.com>
Fixes: 63940449555e7 ("eventfs: Implement eventfs lookup, read, open functions")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit f2f496370afcbc5227d7002da28c74b91fed12ff)
---
fs/tracefs/event_inode.c | 2 ++
fs/tracefs/internal.h | 6 +++---
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 9f612a8f009d..1ce73acf3df0 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -824,6 +824,8 @@ static void eventfs_remove_rec(struct eventfs_inode *ei, struct list_head *head,
eventfs_remove_rec(ei_child, head, level + 1);
}
+ ei->is_freed = 1;
+
list_del_rcu(&ei->list);
list_add_tail(&ei->del_list, head);
}
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 64fde9490f52..c7d88aaa949f 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -23,6 +23,7 @@ struct tracefs_inode {
* @d_parent: pointer to the parent's dentry
* @d_children: The array of dentries to represent the files when created
* @data: The private data to pass to the callbacks
+ * @is_freed: Flag set if the eventfs is on its way to be freed
* @nr_entries: The number of items in @entries
*/
struct eventfs_inode {
@@ -38,14 +39,13 @@ struct eventfs_inode {
* Union - used for deletion
* @del_list: list of eventfs_inode to delete
* @rcu: eventfs_inode to delete in RCU
- * @is_freed: node is freed if one of the above is set
*/
union {
struct list_head del_list;
struct rcu_head rcu;
- unsigned long is_freed;
};
- int nr_entries;
+ unsigned int is_freed:1;
+ unsigned int nr_entries:31;
};
static inline struct tracefs_inode *get_tracefs(const struct inode *inode)
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 17/57] eventfs: Have a free_ei() that just frees the eventfs_inode
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (15 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 16/57] eventfs: Remove "is_freed" union with rcu head Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 18/57] eventfs: Test for ei->is_freed when accessing ei->dentry Steven Rostedt
` (40 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Ajay Kaher,
Andrew Morton
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
As the eventfs_inode is freed in two different locations, make a helper
function free_ei() to make sure all the allocated fields of the
eventfs_inode is freed.
This requires renaming the existing free_ei() which is called by the srcu
handler to free_rcu_ei() and have free_ei() just do the freeing, where
free_rcu_ei() will call it.
Link: https://lkml.kernel.org/r/20231101172649.265214087@goodmis.org
Cc: Ajay Kaher <akaher@vmware.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit db3a397209b00d2e4e0a068608e5c546fc064b82)
---
fs/tracefs/event_inode.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 1ce73acf3df0..dd5971855732 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -129,6 +129,13 @@ static struct dentry *create_dir(const char *name, struct dentry *parent)
return eventfs_end_creating(dentry);
}
+static void free_ei(struct eventfs_inode *ei)
+{
+ kfree_const(ei->name);
+ kfree(ei->d_children);
+ kfree(ei);
+}
+
/**
* eventfs_set_ei_status_free - remove the dentry reference from an eventfs_inode
* @ti: the tracefs_inode of the dentry
@@ -168,9 +175,7 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
eventfs_remove_dir(ei_child);
}
- kfree_const(ei->name);
- kfree(ei->d_children);
- kfree(ei);
+ free_ei(ei);
return;
}
@@ -784,13 +789,11 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
return ERR_PTR(-ENOMEM);
}
-static void free_ei(struct rcu_head *head)
+static void free_rcu_ei(struct rcu_head *head)
{
struct eventfs_inode *ei = container_of(head, struct eventfs_inode, rcu);
- kfree_const(ei->name);
- kfree(ei->d_children);
- kfree(ei);
+ free_ei(ei);
}
/**
@@ -881,7 +884,7 @@ void eventfs_remove_dir(struct eventfs_inode *ei)
for (i = 0; i < ei->nr_entries; i++)
unhook_dentry(&ei->d_children[i], &dentry_list);
unhook_dentry(&ei->dentry, &dentry_list);
- call_srcu(&eventfs_srcu, &ei->rcu, free_ei);
+ call_srcu(&eventfs_srcu, &ei->rcu, free_rcu_ei);
}
mutex_unlock(&eventfs_mutex);
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 18/57] eventfs: Test for ei->is_freed when accessing ei->dentry
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (16 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 17/57] eventfs: Have a free_ei() that just frees the eventfs_inode Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 19/57] eventfs: Save ownership and mode Steven Rostedt
` (39 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Ajay Kaher,
Andrew Morton, Linux Kernel Functional Testing, Naresh Kamboju,
Beau Belgrave
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The eventfs_inode (ei) is protected by SRCU, but the ei->dentry is not. It
is protected by the eventfs_mutex. Anytime the eventfs_mutex is released,
and access to the ei->dentry needs to be done, it should first check if
ei->is_freed is set under the eventfs_mutex. If it is, then the ei->dentry
is invalid and must not be used. The ei->dentry must only be accessed
under the eventfs_mutex and after checking if ei->is_freed is set.
When the ei is being freed, it will (under the eventfs_mutex) set is_freed
and at the same time move the dentry to a free list to be cleared after
the eventfs_mutex is released. This means that any access to the
ei->dentry must check first if ei->is_freed is set, because if it is, then
the dentry is on its way to be freed.
Also add comments to describe this better.
Link: https://lore.kernel.org/all/CA+G9fYt6pY+tMZEOg=SoEywQOe19fGP3uR15SGowkdK+_X85Cg@mail.gmail.com/
Link: https://lore.kernel.org/all/CA+G9fYuDP3hVQ3t7FfrBAjd_WFVSurMgCepTxunSJf=MTe=6aA@mail.gmail.com/
Link: https://lkml.kernel.org/r/20231101172649.477608228@goodmis.org
Cc: Ajay Kaher <akaher@vmware.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: Beau Belgrave <beaub@linux.microsoft.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 77a06c33a22d13f3a6e31f06f6ee6bca666e6898)
---
fs/tracefs/event_inode.c | 45 ++++++++++++++++++++++++++++++++++------
fs/tracefs/internal.h | 3 ++-
2 files changed, 41 insertions(+), 7 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index dd5971855732..e9625732c52d 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -24,7 +24,20 @@
#include <linux/delay.h>
#include "internal.h"
+/*
+ * eventfs_mutex protects the eventfs_inode (ei) dentry. Any access
+ * to the ei->dentry must be done under this mutex and after checking
+ * if ei->is_freed is not set. The ei->dentry is released under the
+ * mutex at the same time ei->is_freed is set. If ei->is_freed is set
+ * then the ei->dentry is invalid.
+ */
static DEFINE_MUTEX(eventfs_mutex);
+
+/*
+ * The eventfs_inode (ei) itself is protected by SRCU. It is released from
+ * its parent's list and will have is_freed set (under eventfs_mutex).
+ * After the SRCU grace period is over, the ei may be freed.
+ */
DEFINE_STATIC_SRCU(eventfs_srcu);
static struct dentry *eventfs_root_lookup(struct inode *dir,
@@ -239,6 +252,10 @@ create_file_dentry(struct eventfs_inode *ei, struct dentry **e_dentry,
bool invalidate = false;
mutex_lock(&eventfs_mutex);
+ if (ei->is_freed) {
+ mutex_unlock(&eventfs_mutex);
+ return NULL;
+ }
/* If the e_dentry already has a dentry, use it */
if (*e_dentry) {
/* lookup does not need to up the ref count */
@@ -312,6 +329,8 @@ static void eventfs_post_create_dir(struct eventfs_inode *ei)
struct eventfs_inode *ei_child;
struct tracefs_inode *ti;
+ lockdep_assert_held(&eventfs_mutex);
+
/* srcu lock already held */
/* fill parent-child relation */
list_for_each_entry_srcu(ei_child, &ei->children, list,
@@ -325,6 +344,7 @@ static void eventfs_post_create_dir(struct eventfs_inode *ei)
/**
* create_dir_dentry - Create a directory dentry for the eventfs_inode
+ * @pei: The eventfs_inode parent of ei.
* @ei: The eventfs_inode to create the directory for
* @parent: The dentry of the parent of this directory
* @lookup: True if this is called by the lookup code
@@ -332,12 +352,17 @@ static void eventfs_post_create_dir(struct eventfs_inode *ei)
* This creates and attaches a directory dentry to the eventfs_inode @ei.
*/
static struct dentry *
-create_dir_dentry(struct eventfs_inode *ei, struct dentry *parent, bool lookup)
+create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
+ struct dentry *parent, bool lookup)
{
bool invalidate = false;
struct dentry *dentry = NULL;
mutex_lock(&eventfs_mutex);
+ if (pei->is_freed || ei->is_freed) {
+ mutex_unlock(&eventfs_mutex);
+ return NULL;
+ }
if (ei->dentry) {
/* If the dentry already has a dentry, use it */
dentry = ei->dentry;
@@ -440,7 +465,7 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
*/
mutex_lock(&eventfs_mutex);
ei = READ_ONCE(ti->private);
- if (ei)
+ if (ei && !ei->is_freed)
ei_dentry = READ_ONCE(ei->dentry);
mutex_unlock(&eventfs_mutex);
@@ -454,7 +479,7 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
if (strcmp(ei_child->name, name) != 0)
continue;
ret = simple_lookup(dir, dentry, flags);
- create_dir_dentry(ei_child, ei_dentry, true);
+ create_dir_dentry(ei, ei_child, ei_dentry, true);
created = true;
break;
}
@@ -588,7 +613,7 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
list_for_each_entry_srcu(ei_child, &ei->children, list,
srcu_read_lock_held(&eventfs_srcu)) {
- d = create_dir_dentry(ei_child, parent, false);
+ d = create_dir_dentry(ei, ei_child, parent, false);
if (d) {
ret = add_dentries(&dentries, d, cnt);
if (ret < 0)
@@ -705,12 +730,20 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode
ei->nr_entries = size;
ei->data = data;
INIT_LIST_HEAD(&ei->children);
+ INIT_LIST_HEAD(&ei->list);
mutex_lock(&eventfs_mutex);
- list_add_tail(&ei->list, &parent->children);
- ei->d_parent = parent->dentry;
+ if (!parent->is_freed) {
+ list_add_tail(&ei->list, &parent->children);
+ ei->d_parent = parent->dentry;
+ }
mutex_unlock(&eventfs_mutex);
+ /* Was the parent freed? */
+ if (list_empty(&ei->list)) {
+ free_ei(ei);
+ ei = NULL;
+ }
return ei;
}
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index c7d88aaa949f..5a98e87dd3d1 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -24,6 +24,7 @@ struct tracefs_inode {
* @d_children: The array of dentries to represent the files when created
* @data: The private data to pass to the callbacks
* @is_freed: Flag set if the eventfs is on its way to be freed
+ * Note if is_freed is set, then dentry is corrupted.
* @nr_entries: The number of items in @entries
*/
struct eventfs_inode {
@@ -31,7 +32,7 @@ struct eventfs_inode {
const struct eventfs_entry *entries;
const char *name;
struct list_head children;
- struct dentry *dentry;
+ struct dentry *dentry; /* Check is_freed to access */
struct dentry *d_parent;
struct dentry **d_children;
void *data;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 19/57] eventfs: Save ownership and mode
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (17 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 18/57] eventfs: Test for ei->is_freed when accessing ei->dentry Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 20/57] eventfs: Hold eventfs_mutex when calling callback functions Steven Rostedt
` (38 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Ajay Kaher,
Andrew Morton
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Now that inodes and dentries are created on the fly, they are also
reclaimed on memory pressure. Since the ownership and file mode are saved
in the inode, if they are freed, any changes to the ownership and mode
will be lost.
To counter this, if the user changes the permissions or ownership, save
them, and when creating the inodes again, restore those changes.
Link: https://lkml.kernel.org/r/20231101172649.691841445@goodmis.org
Cc: stable@vger.kernel.org
Cc: Ajay Kaher <akaher@vmware.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 63940449555e7 ("eventfs: Implement eventfs lookup, read, open functions")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 28e12c09f5aa081b2d13d1340e3610070b6c624d)
---
fs/tracefs/event_inode.c | 148 +++++++++++++++++++++++++++++++++++----
fs/tracefs/internal.h | 16 +++++
2 files changed, 151 insertions(+), 13 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index e9625732c52d..93d08e552483 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -40,6 +40,15 @@ static DEFINE_MUTEX(eventfs_mutex);
*/
DEFINE_STATIC_SRCU(eventfs_srcu);
+/* Mode is unsigned short, use the upper bits for flags */
+enum {
+ EVENTFS_SAVE_MODE = BIT(16),
+ EVENTFS_SAVE_UID = BIT(17),
+ EVENTFS_SAVE_GID = BIT(18),
+};
+
+#define EVENTFS_MODE_MASK (EVENTFS_SAVE_MODE - 1)
+
static struct dentry *eventfs_root_lookup(struct inode *dir,
struct dentry *dentry,
unsigned int flags);
@@ -47,8 +56,89 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file);
static int dcache_readdir_wrapper(struct file *file, struct dir_context *ctx);
static int eventfs_release(struct inode *inode, struct file *file);
+static void update_attr(struct eventfs_attr *attr, struct iattr *iattr)
+{
+ unsigned int ia_valid = iattr->ia_valid;
+
+ if (ia_valid & ATTR_MODE) {
+ attr->mode = (attr->mode & ~EVENTFS_MODE_MASK) |
+ (iattr->ia_mode & EVENTFS_MODE_MASK) |
+ EVENTFS_SAVE_MODE;
+ }
+ if (ia_valid & ATTR_UID) {
+ attr->mode |= EVENTFS_SAVE_UID;
+ attr->uid = iattr->ia_uid;
+ }
+ if (ia_valid & ATTR_GID) {
+ attr->mode |= EVENTFS_SAVE_GID;
+ attr->gid = iattr->ia_gid;
+ }
+}
+
+static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
+ struct iattr *iattr)
+{
+ const struct eventfs_entry *entry;
+ struct eventfs_inode *ei;
+ const char *name;
+ int ret;
+
+ mutex_lock(&eventfs_mutex);
+ ei = dentry->d_fsdata;
+ /* The LSB is set when the eventfs_inode is being freed */
+ if (((unsigned long)ei & 1UL) || ei->is_freed) {
+ /* Do not allow changes if the event is about to be removed. */
+ mutex_unlock(&eventfs_mutex);
+ return -ENODEV;
+ }
+
+ /* Preallocate the children mode array if necessary */
+ if (!(dentry->d_inode->i_mode & S_IFDIR)) {
+ if (!ei->entry_attrs) {
+ ei->entry_attrs = kzalloc(sizeof(*ei->entry_attrs) * ei->nr_entries,
+ GFP_KERNEL);
+ if (!ei->entry_attrs) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+ }
+
+ ret = simple_setattr(idmap, dentry, iattr);
+ if (ret < 0)
+ goto out;
+
+ /*
+ * If this is a dir, then update the ei cache, only the file
+ * mode is saved in the ei->m_children, and the ownership is
+ * determined by the parent directory.
+ */
+ if (dentry->d_inode->i_mode & S_IFDIR) {
+ update_attr(&ei->attr, iattr);
+
+ } else {
+ name = dentry->d_name.name;
+
+ for (int i = 0; i < ei->nr_entries; i++) {
+ entry = &ei->entries[i];
+ if (strcmp(name, entry->name) == 0) {
+ update_attr(&ei->entry_attrs[i], iattr);
+ break;
+ }
+ }
+ }
+ out:
+ mutex_unlock(&eventfs_mutex);
+ return ret;
+}
+
static const struct inode_operations eventfs_root_dir_inode_operations = {
.lookup = eventfs_root_lookup,
+ .setattr = eventfs_set_attr,
+};
+
+static const struct inode_operations eventfs_file_inode_operations = {
+ .setattr = eventfs_set_attr,
};
static const struct file_operations eventfs_file_operations = {
@@ -59,10 +149,30 @@ static const struct file_operations eventfs_file_operations = {
.release = eventfs_release,
};
+static void update_inode_attr(struct inode *inode, struct eventfs_attr *attr, umode_t mode)
+{
+ if (!attr) {
+ inode->i_mode = mode;
+ return;
+ }
+
+ if (attr->mode & EVENTFS_SAVE_MODE)
+ inode->i_mode = attr->mode & EVENTFS_MODE_MASK;
+ else
+ inode->i_mode = mode;
+
+ if (attr->mode & EVENTFS_SAVE_UID)
+ inode->i_uid = attr->uid;
+
+ if (attr->mode & EVENTFS_SAVE_GID)
+ inode->i_gid = attr->gid;
+}
+
/**
* create_file - create a file in the tracefs filesystem
* @name: the name of the file to create.
* @mode: the permission that the file should have.
+ * @attr: saved attributes changed by user
* @parent: parent dentry for this file.
* @data: something that the caller will want to get to later on.
* @fop: struct file_operations that should be used for this file.
@@ -72,6 +182,7 @@ static const struct file_operations eventfs_file_operations = {
* call.
*/
static struct dentry *create_file(const char *name, umode_t mode,
+ struct eventfs_attr *attr,
struct dentry *parent, void *data,
const struct file_operations *fop)
{
@@ -95,7 +206,10 @@ static struct dentry *create_file(const char *name, umode_t mode,
if (unlikely(!inode))
return eventfs_failed_creating(dentry);
- inode->i_mode = mode;
+ /* If the user updated the directory's attributes, use them */
+ update_inode_attr(inode, attr, mode);
+
+ inode->i_op = &eventfs_file_inode_operations;
inode->i_fop = fop;
inode->i_private = data;
@@ -108,19 +222,19 @@ static struct dentry *create_file(const char *name, umode_t mode,
/**
* create_dir - create a dir in the tracefs filesystem
- * @name: the name of the file to create.
+ * @ei: the eventfs_inode that represents the directory to create
* @parent: parent dentry for this file.
*
* This function will create a dentry for a directory represented by
* a eventfs_inode.
*/
-static struct dentry *create_dir(const char *name, struct dentry *parent)
+static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent)
{
struct tracefs_inode *ti;
struct dentry *dentry;
struct inode *inode;
- dentry = eventfs_start_creating(name, parent);
+ dentry = eventfs_start_creating(ei->name, parent);
if (IS_ERR(dentry))
return dentry;
@@ -128,7 +242,9 @@ static struct dentry *create_dir(const char *name, struct dentry *parent)
if (unlikely(!inode))
return eventfs_failed_creating(dentry);
- inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
+ /* If the user updated the directory's attributes, use them */
+ update_inode_attr(inode, &ei->attr, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO);
+
inode->i_op = &eventfs_root_dir_inode_operations;
inode->i_fop = &eventfs_file_operations;
@@ -146,6 +262,7 @@ static void free_ei(struct eventfs_inode *ei)
{
kfree_const(ei->name);
kfree(ei->d_children);
+ kfree(ei->entry_attrs);
kfree(ei);
}
@@ -231,7 +348,7 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
/**
* create_file_dentry - create a dentry for a file of an eventfs_inode
* @ei: the eventfs_inode that the file will be created under
- * @e_dentry: a pointer to the d_children[] of the @ei
+ * @idx: the index into the d_children[] of the @ei
* @parent: The parent dentry of the created file.
* @name: The name of the file to create
* @mode: The mode of the file.
@@ -244,10 +361,12 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
* just do a dget() on it and return. Otherwise create the dentry and attach it.
*/
static struct dentry *
-create_file_dentry(struct eventfs_inode *ei, struct dentry **e_dentry,
+create_file_dentry(struct eventfs_inode *ei, int idx,
struct dentry *parent, const char *name, umode_t mode, void *data,
const struct file_operations *fops, bool lookup)
{
+ struct eventfs_attr *attr = NULL;
+ struct dentry **e_dentry = &ei->d_children[idx];
struct dentry *dentry;
bool invalidate = false;
@@ -264,13 +383,18 @@ create_file_dentry(struct eventfs_inode *ei, struct dentry **e_dentry,
mutex_unlock(&eventfs_mutex);
return *e_dentry;
}
+
+ /* ei->entry_attrs are protected by SRCU */
+ if (ei->entry_attrs)
+ attr = &ei->entry_attrs[idx];
+
mutex_unlock(&eventfs_mutex);
/* The lookup already has the parent->d_inode locked */
if (!lookup)
inode_lock(parent->d_inode);
- dentry = create_file(name, mode, parent, data, fops);
+ dentry = create_file(name, mode, attr, parent, data, fops);
if (!lookup)
inode_unlock(parent->d_inode);
@@ -378,7 +502,7 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
if (!lookup)
inode_lock(parent->d_inode);
- dentry = create_dir(ei->name, parent);
+ dentry = create_dir(ei, parent);
if (!lookup)
inode_unlock(parent->d_inode);
@@ -495,8 +619,7 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
if (r <= 0)
continue;
ret = simple_lookup(dir, dentry, flags);
- create_file_dentry(ei, &ei->d_children[i],
- ei_dentry, name, mode, cdata,
+ create_file_dentry(ei, i, ei_dentry, name, mode, cdata,
fops, true);
break;
}
@@ -629,8 +752,7 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
r = entry->callback(name, &mode, &cdata, &fops);
if (r <= 0)
continue;
- d = create_file_dentry(ei, &ei->d_children[i],
- parent, name, mode, cdata, fops, false);
+ d = create_file_dentry(ei, i, parent, name, mode, cdata, fops, false);
if (d) {
ret = add_dentries(&dentries, d, cnt);
if (ret < 0)
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 5a98e87dd3d1..5f60bcd69289 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -13,6 +13,18 @@ struct tracefs_inode {
struct inode vfs_inode;
};
+/*
+ * struct eventfs_attr - cache the mode and ownership of a eventfs entry
+ * @mode: saved mode plus flags of what is saved
+ * @uid: saved uid if changed
+ * @gid: saved gid if changed
+ */
+struct eventfs_attr {
+ int mode;
+ kuid_t uid;
+ kgid_t gid;
+};
+
/*
* struct eventfs_inode - hold the properties of the eventfs directories.
* @list: link list into the parent directory
@@ -22,6 +34,8 @@ struct tracefs_inode {
* @dentry: the dentry of the directory
* @d_parent: pointer to the parent's dentry
* @d_children: The array of dentries to represent the files when created
+ * @entry_attrs: Saved mode and ownership of the @d_children
+ * @attr: Saved mode and ownership of eventfs_inode itself
* @data: The private data to pass to the callbacks
* @is_freed: Flag set if the eventfs is on its way to be freed
* Note if is_freed is set, then dentry is corrupted.
@@ -35,6 +49,8 @@ struct eventfs_inode {
struct dentry *dentry; /* Check is_freed to access */
struct dentry *d_parent;
struct dentry **d_children;
+ struct eventfs_attr *entry_attrs;
+ struct eventfs_attr attr;
void *data;
/*
* Union - used for deletion
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 20/57] eventfs: Hold eventfs_mutex when calling callback functions
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (18 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 19/57] eventfs: Save ownership and mode Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 21/57] eventfs: Delete eventfs_inode when the last dentry is freed Steven Rostedt
` (37 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Ajay Kaher,
Andrew Morton, Linux Kernel Functional Testing, Naresh Kamboju
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The callback function that is used to create inodes and dentries is not
protected by anything and the data that is passed to it could become
stale. After eventfs_remove_dir() is called by the tracing system, it is
free to remove the events that are associated to that directory.
Unfortunately, that means the callbacks must not be called after that.
CPU0 CPU1
---- ----
eventfs_root_lookup() {
eventfs_remove_dir() {
mutex_lock(&event_mutex);
ei->is_freed = set;
mutex_unlock(&event_mutex);
}
kfree(event_call);
for (...) {
entry = &ei->entries[i];
r = entry->callback() {
call = data; // call == event_call above
if (call->flags ...)
[ USE AFTER FREE BUG ]
The safest way to protect this is to wrap the callback with:
mutex_lock(&eventfs_mutex);
if (!ei->is_freed)
r = entry->callback();
else
r = -1;
mutex_unlock(&eventfs_mutex);
This will make sure that the callback will not be called after it is
freed. But now it needs to be known that the callback is called while
holding internal eventfs locks, and that it must not call back into the
eventfs / tracefs system. There's no reason it should anyway, but document
that as well.
Link: https://lore.kernel.org/all/CA+G9fYu9GOEbD=rR5eMR-=HJ8H6rMsbzDC2ZY5=Y50WpWAE7_Q@mail.gmail.com/
Link: https://lkml.kernel.org/r/20231101172649.906696613@goodmis.org
Cc: Ajay Kaher <akaher@vmware.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 44365329f8219fc379097c2c9a75ff53f123764f)
---
fs/tracefs/event_inode.c | 22 ++++++++++++++++++--
include/linux/tracefs.h | 43 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 63 insertions(+), 2 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 93d08e552483..8ac9abf7a3d5 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -615,7 +615,13 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
entry = &ei->entries[i];
if (strcmp(name, entry->name) == 0) {
void *cdata = data;
- r = entry->callback(name, &mode, &cdata, &fops);
+ mutex_lock(&eventfs_mutex);
+ /* If ei->is_freed, then the event itself may be too */
+ if (!ei->is_freed)
+ r = entry->callback(name, &mode, &cdata, &fops);
+ else
+ r = -1;
+ mutex_unlock(&eventfs_mutex);
if (r <= 0)
continue;
ret = simple_lookup(dir, dentry, flags);
@@ -749,7 +755,13 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
void *cdata = data;
entry = &ei->entries[i];
name = entry->name;
- r = entry->callback(name, &mode, &cdata, &fops);
+ mutex_lock(&eventfs_mutex);
+ /* If ei->is_freed, then the event itself may be too */
+ if (!ei->is_freed)
+ r = entry->callback(name, &mode, &cdata, &fops);
+ else
+ r = -1;
+ mutex_unlock(&eventfs_mutex);
if (r <= 0)
continue;
d = create_file_dentry(ei, i, parent, name, mode, cdata, fops, false);
@@ -819,6 +831,10 @@ static int dcache_readdir_wrapper(struct file *file, struct dir_context *ctx)
* data = A pointer to @data, and the callback may replace it, which will
* cause the file created to pass the new data to the open() call.
* fops = the fops to use for the created file.
+ *
+ * NB. @callback is called while holding internal locks of the eventfs
+ * system. The callback must not call any code that might also call into
+ * the tracefs or eventfs system or it will risk creating a deadlock.
*/
struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode *parent,
const struct eventfs_entry *entries,
@@ -878,6 +894,8 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode
* @data: The default data to pass to the files (an entry may override it).
*
* This function creates the top of the trace event directory.
+ *
+ * See eventfs_create_dir() for use of @entries.
*/
struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry *parent,
const struct eventfs_entry *entries,
diff --git a/include/linux/tracefs.h b/include/linux/tracefs.h
index 13359b1a35d1..7a5fe17b6bf9 100644
--- a/include/linux/tracefs.h
+++ b/include/linux/tracefs.h
@@ -23,9 +23,52 @@ struct file_operations;
struct eventfs_file;
+/**
+ * eventfs_callback - A callback function to create dynamic files in eventfs
+ * @name: The name of the file that is to be created
+ * @mode: return the file mode for the file (RW access, etc)
+ * @data: data to pass to the created file ops
+ * @fops: the file operations of the created file
+ *
+ * The evetnfs files are dynamically created. The struct eventfs_entry array
+ * is passed to eventfs_create_dir() or eventfs_create_events_dir() that will
+ * be used to create the files within those directories. When a lookup
+ * or access to a file within the directory is made, the struct eventfs_entry
+ * array is used to find a callback() with the matching name that is being
+ * referenced (for lookups, the entire array is iterated and each callback
+ * will be called).
+ *
+ * The callback will be called with @name for the name of the file to create.
+ * The callback can return less than 1 to indicate that no file should be
+ * created.
+ *
+ * If a file is to be created, then @mode should be populated with the file
+ * mode (permissions) for which the file is created for. This would be
+ * used to set the created inode i_mode field.
+ *
+ * The @data should be set to the data passed to the other file operations
+ * (read, write, etc). Note, @data will also point to the data passed in
+ * to eventfs_create_dir() or eventfs_create_events_dir(), but the callback
+ * can replace the data if it chooses to. Otherwise, the original data
+ * will be used for the file operation functions.
+ *
+ * The @fops should be set to the file operations that will be used to create
+ * the inode.
+ *
+ * NB. This callback is called while holding internal locks of the eventfs
+ * system. The callback must not call any code that might also call into
+ * the tracefs or eventfs system or it will risk creating a deadlock.
+ */
typedef int (*eventfs_callback)(const char *name, umode_t *mode, void **data,
const struct file_operations **fops);
+/**
+ * struct eventfs_entry - dynamically created eventfs file call back handler
+ * @name: Then name of the dynamic file in an eventfs directory
+ * @callback: The callback to get the fops of the file when it is created
+ *
+ * See evenfs_callback() typedef for how to set up @callback.
+ */
struct eventfs_entry {
const char *name;
eventfs_callback callback;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 21/57] eventfs: Delete eventfs_inode when the last dentry is freed
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (19 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 20/57] eventfs: Hold eventfs_mutex when calling callback functions Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 22/57] eventfs: Remove special processing of dput() of events directory Steven Rostedt
` (36 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Ajay Kaher
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
There exists a race between holding a reference of an eventfs_inode dentry
and the freeing of the eventfs_inode. If user space has a dentry held long
enough, it may still be able to access the dentry's eventfs_inode after it
has been freed.
To prevent this, have he eventfs_inode freed via the last dput() (or via
RCU if the eventfs_inode does not have a dentry).
This means reintroducing the eventfs_inode del_list field at a temporary
place to put the eventfs_inode. It needs to mark it as freed (via the
list) but also must invalidate the dentry immediately as the return from
eventfs_remove_dir() expects that they are. But the dentry invalidation
must not be called under the eventfs_mutex, so it must be done after the
eventfs_inode is marked as free (put on a deletion list).
Link: https://lkml.kernel.org/r/20231101172650.123479767@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ajay Kaher <akaher@vmware.com>
Fixes: 5bdcd5f5331a2 ("eventfs: Implement removal of meta data from eventfs")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 020010fbfa202aa528a52743eba4ab0da3400a4e)
---
fs/tracefs/event_inode.c | 146 ++++++++++++++++++---------------------
fs/tracefs/internal.h | 2 +
2 files changed, 69 insertions(+), 79 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 8ac9abf7a3d5..0a04ae0ca8c8 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -85,8 +85,7 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
mutex_lock(&eventfs_mutex);
ei = dentry->d_fsdata;
- /* The LSB is set when the eventfs_inode is being freed */
- if (((unsigned long)ei & 1UL) || ei->is_freed) {
+ if (ei->is_freed) {
/* Do not allow changes if the event is about to be removed. */
mutex_unlock(&eventfs_mutex);
return -ENODEV;
@@ -276,35 +275,17 @@ static void free_ei(struct eventfs_inode *ei)
void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
{
struct tracefs_inode *ti_parent;
- struct eventfs_inode *ei_child, *tmp;
struct eventfs_inode *ei;
int i;
/* The top level events directory may be freed by this */
if (unlikely(ti->flags & TRACEFS_EVENT_TOP_INODE)) {
- LIST_HEAD(ef_del_list);
-
mutex_lock(&eventfs_mutex);
-
ei = ti->private;
-
- /* Record all the top level files */
- list_for_each_entry_srcu(ei_child, &ei->children, list,
- lockdep_is_held(&eventfs_mutex)) {
- list_add_tail(&ei_child->del_list, &ef_del_list);
- }
-
/* Nothing should access this, but just in case! */
ti->private = NULL;
-
mutex_unlock(&eventfs_mutex);
- /* Now safely free the top level files and their children */
- list_for_each_entry_safe(ei_child, tmp, &ef_del_list, del_list) {
- list_del(&ei_child->del_list);
- eventfs_remove_dir(ei_child);
- }
-
free_ei(ei);
return;
}
@@ -319,14 +300,6 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
if (!ei)
goto out;
- /*
- * If ei was freed, then the LSB bit is set for d_fsdata.
- * But this should not happen, as it should still have a
- * ref count that prevents it. Warn in case it does.
- */
- if (WARN_ON_ONCE((unsigned long)ei & 1))
- goto out;
-
/* This could belong to one of the files of the ei */
if (ei->dentry != dentry) {
for (i = 0; i < ei->nr_entries; i++) {
@@ -336,6 +309,8 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
if (WARN_ON_ONCE(i == ei->nr_entries))
goto out;
ei->d_children[i] = NULL;
+ } else if (ei->is_freed) {
+ free_ei(ei);
} else {
ei->dentry = NULL;
}
@@ -962,13 +937,65 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
return ERR_PTR(-ENOMEM);
}
+static LLIST_HEAD(free_list);
+
+static void eventfs_workfn(struct work_struct *work)
+{
+ struct eventfs_inode *ei, *tmp;
+ struct llist_node *llnode;
+
+ llnode = llist_del_all(&free_list);
+ llist_for_each_entry_safe(ei, tmp, llnode, llist) {
+ /* This dput() matches the dget() from unhook_dentry() */
+ for (int i = 0; i < ei->nr_entries; i++) {
+ if (ei->d_children[i])
+ dput(ei->d_children[i]);
+ }
+ /* This should only get here if it had a dentry */
+ if (!WARN_ON_ONCE(!ei->dentry))
+ dput(ei->dentry);
+ }
+}
+
+static DECLARE_WORK(eventfs_work, eventfs_workfn);
+
static void free_rcu_ei(struct rcu_head *head)
{
struct eventfs_inode *ei = container_of(head, struct eventfs_inode, rcu);
+ if (ei->dentry) {
+ /* Do not free the ei until all references of dentry are gone */
+ if (llist_add(&ei->llist, &free_list))
+ queue_work(system_unbound_wq, &eventfs_work);
+ return;
+ }
+
+ /* If the ei doesn't have a dentry, neither should its children */
+ for (int i = 0; i < ei->nr_entries; i++) {
+ WARN_ON_ONCE(ei->d_children[i]);
+ }
+
free_ei(ei);
}
+static void unhook_dentry(struct dentry *dentry)
+{
+ if (!dentry)
+ return;
+
+ /* Keep the dentry from being freed yet (see eventfs_workfn()) */
+ dget(dentry);
+
+ dentry->d_fsdata = NULL;
+ d_invalidate(dentry);
+ mutex_lock(&eventfs_mutex);
+ /* dentry should now have at least a single reference */
+ WARN_ONCE((int)d_count(dentry) < 1,
+ "dentry %px (%s) less than one reference (%d) after invalidate\n",
+ dentry, dentry->d_name.name, d_count(dentry));
+ mutex_unlock(&eventfs_mutex);
+}
+
/**
* eventfs_remove_rec - remove eventfs dir or file from list
* @ei: eventfs_inode to be removed.
@@ -1006,33 +1033,6 @@ static void eventfs_remove_rec(struct eventfs_inode *ei, struct list_head *head,
list_add_tail(&ei->del_list, head);
}
-static void unhook_dentry(struct dentry **dentry, struct dentry **list)
-{
- if (*dentry) {
- unsigned long ptr = (unsigned long)*list;
-
- /* Keep the dentry from being freed yet */
- dget(*dentry);
-
- /*
- * Paranoid: The dget() above should prevent the dentry
- * from being freed and calling eventfs_set_ei_status_free().
- * But just in case, set the link list LSB pointer to 1
- * and have eventfs_set_ei_status_free() check that to
- * make sure that if it does happen, it will not think
- * the d_fsdata is an eventfs_inode.
- *
- * For this to work, no eventfs_inode should be allocated
- * on a odd space, as the ef should always be allocated
- * to be at least word aligned. Check for that too.
- */
- WARN_ON_ONCE(ptr & 1);
-
- (*dentry)->d_fsdata = (void *)(ptr | 1);
- *list = *dentry;
- *dentry = NULL;
- }
-}
/**
* eventfs_remove_dir - remove eventfs dir or file from list
* @ei: eventfs_inode to be removed.
@@ -1043,40 +1043,28 @@ void eventfs_remove_dir(struct eventfs_inode *ei)
{
struct eventfs_inode *tmp;
LIST_HEAD(ei_del_list);
- struct dentry *dentry_list = NULL;
- struct dentry *dentry;
- int i;
if (!ei)
return;
+ /*
+ * Move the deleted eventfs_inodes onto the ei_del_list
+ * which will also set the is_freed value. Note, this has to be
+ * done under the eventfs_mutex, but the deletions of
+ * the dentries must be done outside the eventfs_mutex.
+ * Hence moving them to this temporary list.
+ */
mutex_lock(&eventfs_mutex);
eventfs_remove_rec(ei, &ei_del_list, 0);
+ mutex_unlock(&eventfs_mutex);
list_for_each_entry_safe(ei, tmp, &ei_del_list, del_list) {
- for (i = 0; i < ei->nr_entries; i++)
- unhook_dentry(&ei->d_children[i], &dentry_list);
- unhook_dentry(&ei->dentry, &dentry_list);
+ for (int i = 0; i < ei->nr_entries; i++)
+ unhook_dentry(ei->d_children[i]);
+ unhook_dentry(ei->dentry);
+ list_del(&ei->del_list);
call_srcu(&eventfs_srcu, &ei->rcu, free_rcu_ei);
}
- mutex_unlock(&eventfs_mutex);
-
- while (dentry_list) {
- unsigned long ptr;
-
- dentry = dentry_list;
- ptr = (unsigned long)dentry->d_fsdata & ~1UL;
- dentry_list = (struct dentry *)ptr;
- dentry->d_fsdata = NULL;
- d_invalidate(dentry);
- mutex_lock(&eventfs_mutex);
- /* dentry should now have at least a single reference */
- WARN_ONCE((int)d_count(dentry) < 1,
- "dentry %px (%s) less than one reference (%d) after invalidate\n",
- dentry, dentry->d_name.name, d_count(dentry));
- mutex_unlock(&eventfs_mutex);
- dput(dentry);
- }
}
/**
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 5f60bcd69289..06a1f220b901 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -54,10 +54,12 @@ struct eventfs_inode {
void *data;
/*
* Union - used for deletion
+ * @llist: for calling dput() if needed after RCU
* @del_list: list of eventfs_inode to delete
* @rcu: eventfs_inode to delete in RCU
*/
union {
+ struct llist_node llist;
struct list_head del_list;
struct rcu_head rcu;
};
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 22/57] eventfs: Remove special processing of dput() of events directory
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (20 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 21/57] eventfs: Delete eventfs_inode when the last dentry is freed Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 23/57] eventfs: Use simple_recursive_removal() to clean up dentries Steven Rostedt
` (35 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Ajay Kaher,
Andrew Morton
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The top level events directory is no longer special with regards to how it
should be delete. Remove the extra processing for it in
eventfs_set_ei_status_free().
Link: https://lkml.kernel.org/r/20231101172650.340876747@goodmis.org
Cc: Ajay Kaher <akaher@vmware.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 62d65cac119d08d39f751b4e3e2063ed996edc05)
---
fs/tracefs/event_inode.c | 19 ++-----------------
1 file changed, 2 insertions(+), 17 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 0a04ae0ca8c8..0087a3f455f1 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -274,28 +274,11 @@ static void free_ei(struct eventfs_inode *ei)
*/
void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
{
- struct tracefs_inode *ti_parent;
struct eventfs_inode *ei;
int i;
- /* The top level events directory may be freed by this */
- if (unlikely(ti->flags & TRACEFS_EVENT_TOP_INODE)) {
- mutex_lock(&eventfs_mutex);
- ei = ti->private;
- /* Nothing should access this, but just in case! */
- ti->private = NULL;
- mutex_unlock(&eventfs_mutex);
-
- free_ei(ei);
- return;
- }
-
mutex_lock(&eventfs_mutex);
- ti_parent = get_tracefs(dentry->d_parent->d_inode);
- if (!ti_parent || !(ti_parent->flags & TRACEFS_EVENT_INODE))
- goto out;
-
ei = dentry->d_fsdata;
if (!ei)
goto out;
@@ -920,6 +903,8 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
inode->i_op = &eventfs_root_dir_inode_operations;
inode->i_fop = &eventfs_file_operations;
+ dentry->d_fsdata = ei;
+
/* directory inodes start off with i_nlink == 2 (for "." entry) */
inc_nlink(inode);
d_instantiate(dentry, inode);
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 23/57] eventfs: Use simple_recursive_removal() to clean up dentries
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (21 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 22/57] eventfs: Remove special processing of dput() of events directory Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 24/57] eventfs: Remove expectation that ei->is_freed means ei->dentry == NULL Steven Rostedt
` (34 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Al Viro
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Looking at how dentry is removed via the tracefs system, I found that
eventfs does not do everything that it did under tracefs. The tracefs
removal of a dentry calls simple_recursive_removal() that does a lot more
than a simple d_invalidate().
As it should be a requirement that any eventfs_inode that has a dentry, so
does its parent. When removing a eventfs_inode, if it has a dentry, a call
to simple_recursive_removal() on that dentry should clean up all the
dentries underneath it.
Add WARN_ON_ONCE() to check for the parent having a dentry if any children
do.
Link: https://lore.kernel.org/all/20231101022553.GE1957730@ZenIV/
Link: https://lkml.kernel.org/r/20231101172650.552471568@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Fixes: 5bdcd5f5331a2 ("eventfs: Implement removal of meta data from eventfs")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 407c6726ca71b33330d2d6345d9ea7ebc02575e9)
---
fs/tracefs/event_inode.c | 77 +++++++++++++++++++++++-----------------
fs/tracefs/internal.h | 2 --
2 files changed, 44 insertions(+), 35 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 0087a3f455f1..f8a594a50ae6 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -967,30 +967,29 @@ static void unhook_dentry(struct dentry *dentry)
{
if (!dentry)
return;
-
- /* Keep the dentry from being freed yet (see eventfs_workfn()) */
+ /*
+ * Need to add a reference to the dentry that is expected by
+ * simple_recursive_removal(), which will include a dput().
+ */
dget(dentry);
- dentry->d_fsdata = NULL;
- d_invalidate(dentry);
- mutex_lock(&eventfs_mutex);
- /* dentry should now have at least a single reference */
- WARN_ONCE((int)d_count(dentry) < 1,
- "dentry %px (%s) less than one reference (%d) after invalidate\n",
- dentry, dentry->d_name.name, d_count(dentry));
- mutex_unlock(&eventfs_mutex);
+ /*
+ * Also add a reference for the dput() in eventfs_workfn().
+ * That is required as that dput() will free the ei after
+ * the SRCU grace period is over.
+ */
+ dget(dentry);
}
/**
* eventfs_remove_rec - remove eventfs dir or file from list
* @ei: eventfs_inode to be removed.
- * @head: the list head to place the deleted @ei and children
* @level: prevent recursion from going more than 3 levels deep.
*
* This function recursively removes eventfs_inodes which
* contains info of files and/or directories.
*/
-static void eventfs_remove_rec(struct eventfs_inode *ei, struct list_head *head, int level)
+static void eventfs_remove_rec(struct eventfs_inode *ei, int level)
{
struct eventfs_inode *ei_child;
@@ -1009,13 +1008,26 @@ static void eventfs_remove_rec(struct eventfs_inode *ei, struct list_head *head,
/* search for nested folders or files */
list_for_each_entry_srcu(ei_child, &ei->children, list,
lockdep_is_held(&eventfs_mutex)) {
- eventfs_remove_rec(ei_child, head, level + 1);
+ /* Children only have dentry if parent does */
+ WARN_ON_ONCE(ei_child->dentry && !ei->dentry);
+ eventfs_remove_rec(ei_child, level + 1);
}
+
ei->is_freed = 1;
+ for (int i = 0; i < ei->nr_entries; i++) {
+ if (ei->d_children[i]) {
+ /* Children only have dentry if parent does */
+ WARN_ON_ONCE(!ei->dentry);
+ unhook_dentry(ei->d_children[i]);
+ }
+ }
+
+ unhook_dentry(ei->dentry);
+
list_del_rcu(&ei->list);
- list_add_tail(&ei->del_list, head);
+ call_srcu(&eventfs_srcu, &ei->rcu, free_rcu_ei);
}
/**
@@ -1026,30 +1038,22 @@ static void eventfs_remove_rec(struct eventfs_inode *ei, struct list_head *head,
*/
void eventfs_remove_dir(struct eventfs_inode *ei)
{
- struct eventfs_inode *tmp;
- LIST_HEAD(ei_del_list);
+ struct dentry *dentry;
if (!ei)
return;
- /*
- * Move the deleted eventfs_inodes onto the ei_del_list
- * which will also set the is_freed value. Note, this has to be
- * done under the eventfs_mutex, but the deletions of
- * the dentries must be done outside the eventfs_mutex.
- * Hence moving them to this temporary list.
- */
mutex_lock(&eventfs_mutex);
- eventfs_remove_rec(ei, &ei_del_list, 0);
+ dentry = ei->dentry;
+ eventfs_remove_rec(ei, 0);
mutex_unlock(&eventfs_mutex);
- list_for_each_entry_safe(ei, tmp, &ei_del_list, del_list) {
- for (int i = 0; i < ei->nr_entries; i++)
- unhook_dentry(ei->d_children[i]);
- unhook_dentry(ei->dentry);
- list_del(&ei->del_list);
- call_srcu(&eventfs_srcu, &ei->rcu, free_rcu_ei);
- }
+ /*
+ * If any of the ei children has a dentry, then the ei itself
+ * must have a dentry.
+ */
+ if (dentry)
+ simple_recursive_removal(dentry, NULL);
}
/**
@@ -1060,10 +1064,17 @@ void eventfs_remove_dir(struct eventfs_inode *ei)
*/
void eventfs_remove_events_dir(struct eventfs_inode *ei)
{
- struct dentry *dentry = ei->dentry;
+ struct dentry *dentry;
+ dentry = ei->dentry;
eventfs_remove_dir(ei);
- /* Matches the dget() from eventfs_create_events_dir() */
+ /*
+ * Matches the dget() done by tracefs_start_creating()
+ * in eventfs_create_events_dir() when it the dentry was
+ * created. In other words, it's a normal dentry that
+ * sticks around while the other ei->dentry are created
+ * and destroyed dynamically.
+ */
dput(dentry);
}
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 06a1f220b901..ccee18ca66c7 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -55,12 +55,10 @@ struct eventfs_inode {
/*
* Union - used for deletion
* @llist: for calling dput() if needed after RCU
- * @del_list: list of eventfs_inode to delete
* @rcu: eventfs_inode to delete in RCU
*/
union {
struct llist_node llist;
- struct list_head del_list;
struct rcu_head rcu;
};
unsigned int is_freed:1;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 24/57] eventfs: Remove expectation that ei->is_freed means ei->dentry == NULL
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (22 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 23/57] eventfs: Use simple_recursive_removal() to clean up dentries Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 25/57] eventfs: Do not invalidate dentry in create_file/dir_dentry() Steven Rostedt
` (33 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The logic to free the eventfs_inode (ei) use to set is_freed and clear the
"dentry" field under the eventfs_mutex. But that changed when a race was
found where the ei->dentry needed to be cleared when the last dput() was
called on it. But there was still logic that checked if ei->dentry was not
NULL and is_freed is set, and would warn if it was.
But since that situation was changed and the ei->dentry isn't cleared
until the last dput() is called on it while the ei->is_freed is set, do
not test for that condition anymore, and change the comments to reflect
that.
Link: https://lkml.kernel.org/r/20231120235154.265826243@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 020010fbfa20 ("eventfs: Delete eventfs_inode when the last dentry is freed")
Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 88903daecacf03b1e5636e1b5f18bda5b07030fc)
---
fs/tracefs/event_inode.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index f8a594a50ae6..f239b2b507a4 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -27,16 +27,16 @@
/*
* eventfs_mutex protects the eventfs_inode (ei) dentry. Any access
* to the ei->dentry must be done under this mutex and after checking
- * if ei->is_freed is not set. The ei->dentry is released under the
- * mutex at the same time ei->is_freed is set. If ei->is_freed is set
- * then the ei->dentry is invalid.
+ * if ei->is_freed is not set. When ei->is_freed is set, the dentry
+ * is on its way to being freed after the last dput() is made on it.
*/
static DEFINE_MUTEX(eventfs_mutex);
/*
* The eventfs_inode (ei) itself is protected by SRCU. It is released from
* its parent's list and will have is_freed set (under eventfs_mutex).
- * After the SRCU grace period is over, the ei may be freed.
+ * After the SRCU grace period is over and the last dput() is called
+ * the ei is freed.
*/
DEFINE_STATIC_SRCU(eventfs_srcu);
@@ -365,12 +365,14 @@ create_file_dentry(struct eventfs_inode *ei, int idx,
* created the dentry for this e_dentry. In which case
* use that one.
*
- * Note, with the mutex held, the e_dentry cannot have content
- * and the ei->is_freed be true at the same time.
+ * If ei->is_freed is set, the e_dentry is currently on its
+ * way to being freed, don't return it. If e_dentry is NULL
+ * it means it was already freed.
*/
- dentry = *e_dentry;
- if (WARN_ON_ONCE(dentry && ei->is_freed))
+ if (ei->is_freed)
dentry = NULL;
+ else
+ dentry = *e_dentry;
/* The lookup does not need to up the dentry refcount */
if (dentry && !lookup)
dget(dentry);
@@ -473,8 +475,8 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
* created the dentry for this e_dentry. In which case
* use that one.
*
- * Note, with the mutex held, the e_dentry cannot have content
- * and the ei->is_freed be true at the same time.
+ * If ei->is_freed is set, the e_dentry is currently on its
+ * way to being freed.
*/
dentry = ei->dentry;
if (dentry && !lookup)
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 25/57] eventfs: Do not invalidate dentry in create_file/dir_dentry()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (23 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 24/57] eventfs: Remove expectation that ei->is_freed means ei->dentry == NULL Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 26/57] eventfs: Use GFP_NOFS for allocation when eventfs_mutex is held Steven Rostedt
` (32 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Naresh Kamboju, Linux Kernel Functional Testing
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
With the call to simple_recursive_removal() on the entire eventfs sub
system when the directory is removed, it performs the d_invalidate on all
the dentries when it is removed. There's no need to do clean ups when a
dentry is being created while the directory is being deleted.
As dentries are cleaned up by the simpler_recursive_removal(), trying to
do d_invalidate() in these functions will cause the dentry to be
invalidated twice, and crash the kernel.
Link: https://lore.kernel.org/all/20231116123016.140576-1-naresh.kamboju@linaro.org/
Link: https://lkml.kernel.org/r/20231120235154.422970988@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 407c6726ca71 ("eventfs: Use simple_recursive_removal() to clean up dentries")
Reported-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 71cade82f2b553a74d046c015c986f2df165696f)
---
fs/tracefs/event_inode.c | 19 ++++++-------------
1 file changed, 6 insertions(+), 13 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index f239b2b507a4..3eb6c622a74d 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -326,7 +326,6 @@ create_file_dentry(struct eventfs_inode *ei, int idx,
struct eventfs_attr *attr = NULL;
struct dentry **e_dentry = &ei->d_children[idx];
struct dentry *dentry;
- bool invalidate = false;
mutex_lock(&eventfs_mutex);
if (ei->is_freed) {
@@ -389,17 +388,14 @@ create_file_dentry(struct eventfs_inode *ei, int idx,
* Otherwise it means two dentries exist with the same name.
*/
WARN_ON_ONCE(!ei->is_freed);
- invalidate = true;
+ dentry = NULL;
}
mutex_unlock(&eventfs_mutex);
- if (invalidate)
- d_invalidate(dentry);
-
- if (lookup || invalidate)
+ if (lookup)
dput(dentry);
- return invalidate ? NULL : dentry;
+ return dentry;
}
/**
@@ -439,7 +435,6 @@ static struct dentry *
create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
struct dentry *parent, bool lookup)
{
- bool invalidate = false;
struct dentry *dentry = NULL;
mutex_lock(&eventfs_mutex);
@@ -495,16 +490,14 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
* Otherwise it means two dentries exist with the same name.
*/
WARN_ON_ONCE(!ei->is_freed);
- invalidate = true;
+ dentry = NULL;
}
mutex_unlock(&eventfs_mutex);
- if (invalidate)
- d_invalidate(dentry);
- if (lookup || invalidate)
+ if (lookup)
dput(dentry);
- return invalidate ? NULL : dentry;
+ return dentry;
}
/**
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 26/57] eventfs: Use GFP_NOFS for allocation when eventfs_mutex is held
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (24 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 25/57] eventfs: Do not invalidate dentry in create_file/dir_dentry() Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 27/57] eventfs: Move taking of inode_lock into dcache_dir_open_wrapper() Steven Rostedt
` (31 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Josef Bacik
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
If memory reclaim happens, it can reclaim file system pages. The file
system pages from eventfs may take the eventfs_mutex on reclaim. This
means that allocation while holding the eventfs_mutex must not call into
filesystem reclaim. A lockdep splat uncovered this.
Link: https://lkml.kernel.org/r/20231121231112.373501894@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 28e12c09f5aa0 ("eventfs: Save ownership and mode")
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 4763d635c907baed212664dc579dde1663bb2676)
---
fs/tracefs/event_inode.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 3eb6c622a74d..56d192f0ead8 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -95,7 +95,7 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
if (!(dentry->d_inode->i_mode & S_IFDIR)) {
if (!ei->entry_attrs) {
ei->entry_attrs = kzalloc(sizeof(*ei->entry_attrs) * ei->nr_entries,
- GFP_KERNEL);
+ GFP_NOFS);
if (!ei->entry_attrs) {
ret = -ENOMEM;
goto out;
@@ -627,7 +627,7 @@ static int add_dentries(struct dentry ***dentries, struct dentry *d, int cnt)
{
struct dentry **tmp;
- tmp = krealloc(*dentries, sizeof(d) * (cnt + 2), GFP_KERNEL);
+ tmp = krealloc(*dentries, sizeof(d) * (cnt + 2), GFP_NOFS);
if (!tmp)
return -1;
tmp[cnt] = d;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 27/57] eventfs: Move taking of inode_lock into dcache_dir_open_wrapper()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (25 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 26/57] eventfs: Use GFP_NOFS for allocation when eventfs_mutex is held Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 28/57] eventfs: Do not allow NULL parent to eventfs_start_creating() Steven Rostedt
` (30 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Josef Bacik
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The both create_file_dentry() and create_dir_dentry() takes a boolean
parameter "lookup", as on lookup the inode_lock should already be taken,
but for dcache_dir_open_wrapper() it is not taken.
There's no reason that the dcache_dir_open_wrapper() can't take the
inode_lock before calling these functions. In fact, it's better if it
does, as the lock can be held throughout both directory and file
creations.
This also simplifies the code, and possibly prevents unexpected race
conditions when the lock is released.
Link: https://lkml.kernel.org/r/20231121231112.528544825@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit bcae32c5632fc0a0dbce46fa731cd23403117e66)
---
fs/tracefs/event_inode.c | 16 ++--------------
1 file changed, 2 insertions(+), 14 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 56d192f0ead8..590e8176449b 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -347,15 +347,8 @@ create_file_dentry(struct eventfs_inode *ei, int idx,
mutex_unlock(&eventfs_mutex);
- /* The lookup already has the parent->d_inode locked */
- if (!lookup)
- inode_lock(parent->d_inode);
-
dentry = create_file(name, mode, attr, parent, data, fops);
- if (!lookup)
- inode_unlock(parent->d_inode);
-
mutex_lock(&eventfs_mutex);
if (IS_ERR_OR_NULL(dentry)) {
@@ -453,15 +446,8 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
}
mutex_unlock(&eventfs_mutex);
- /* The lookup already has the parent->d_inode locked */
- if (!lookup)
- inode_lock(parent->d_inode);
-
dentry = create_dir(ei, parent);
- if (!lookup)
- inode_unlock(parent->d_inode);
-
mutex_lock(&eventfs_mutex);
if (IS_ERR_OR_NULL(dentry) && !ei->is_freed) {
@@ -693,6 +679,7 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
return -ENOMEM;
}
+ inode_lock(parent->d_inode);
list_for_each_entry_srcu(ei_child, &ei->children, list,
srcu_read_lock_held(&eventfs_srcu)) {
d = create_dir_dentry(ei, ei_child, parent, false);
@@ -725,6 +712,7 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
cnt++;
}
}
+ inode_unlock(parent->d_inode);
srcu_read_unlock(&eventfs_srcu, idx);
ret = dcache_dir_open(inode, file);
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 28/57] eventfs: Do not allow NULL parent to eventfs_start_creating()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (26 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 27/57] eventfs: Move taking of inode_lock into dcache_dir_open_wrapper() Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 29/57] eventfs: Make sure that parent->d_inode is locked in creating files/dirs Steven Rostedt
` (29 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Josef Bacik
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The eventfs directory is dynamically created via the meta data supplied by
the existing trace events. All files and directories in eventfs has a
parent. Do not allow NULL to be passed into eventfs_start_creating() as
the parent because that should never happen. Warn if it does.
Link: https://lkml.kernel.org/r/20231121231112.693841807@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit fc4561226feaad5fcdcb55646c348d77b8ee69c5)
---
fs/tracefs/inode.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index 34ffb2f8114e..b9ed8db4f6b9 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -509,20 +509,15 @@ struct dentry *eventfs_start_creating(const char *name, struct dentry *parent)
struct dentry *dentry;
int error;
+ /* Must always have a parent. */
+ if (WARN_ON_ONCE(!parent))
+ return ERR_PTR(-EINVAL);
+
error = simple_pin_fs(&trace_fs_type, &tracefs_mount,
&tracefs_mount_count);
if (error)
return ERR_PTR(error);
- /*
- * If the parent is not specified, we create it in the root.
- * We need the root dentry to do this, which is in the super
- * block. A pointer to that is in the struct vfsmount that we
- * have around.
- */
- if (!parent)
- parent = tracefs_mount->mnt_root;
-
if (unlikely(IS_DEADDIR(parent->d_inode)))
dentry = ERR_PTR(-ENOENT);
else
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 29/57] eventfs: Make sure that parent->d_inode is locked in creating files/dirs
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (27 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 28/57] eventfs: Do not allow NULL parent to eventfs_start_creating() Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 30/57] eventfs: Fix events beyond NAME_MAX blocking tasks Steven Rostedt
` (28 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Josef Bacik
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Since the locking of the parent->d_inode has been moved outside the
creation of the files and directories (as it use to be locked via a
conditional), add a WARN_ON_ONCE() to the case that it's not locked.
Link: https://lkml.kernel.org/r/20231121231112.853962542@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit f49f950c217bfb40f11662bab39cb388d41e4cfb)
---
fs/tracefs/event_inode.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 590e8176449b..0b90869fd805 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -327,6 +327,8 @@ create_file_dentry(struct eventfs_inode *ei, int idx,
struct dentry **e_dentry = &ei->d_children[idx];
struct dentry *dentry;
+ WARN_ON_ONCE(!inode_is_locked(parent->d_inode));
+
mutex_lock(&eventfs_mutex);
if (ei->is_freed) {
mutex_unlock(&eventfs_mutex);
@@ -430,6 +432,8 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
{
struct dentry *dentry = NULL;
+ WARN_ON_ONCE(!inode_is_locked(parent->d_inode));
+
mutex_lock(&eventfs_mutex);
if (pei->is_freed || ei->is_freed) {
mutex_unlock(&eventfs_mutex);
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 30/57] eventfs: Fix events beyond NAME_MAX blocking tasks
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (28 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 29/57] eventfs: Make sure that parent->d_inode is locked in creating files/dirs Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 31/57] eventfs: Have event files and directories default to parent uid and gid Steven Rostedt
` (27 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Beau Belgrave
From: Beau Belgrave <beaub@linux.microsoft.com>
Eventfs uses simple_lookup(), however, it will fail if the name of the
entry is beyond NAME_MAX length. When this error is encountered, eventfs
still tries to create dentries instead of skipping the dentry creation.
When the dentry is attempted to be created in this state d_wait_lookup()
will loop forever, waiting for the lookup to be removed.
Fix eventfs to return the error in simple_lookup() back to the caller
instead of continuing to try to create the dentry.
Link: https://lore.kernel.org/linux-trace-kernel/20231210213534.497-1-beaub@linux.microsoft.com
Fixes: 63940449555e ("eventfs: Implement eventfs lookup, read, open functions")
Link: https://lore.kernel.org/linux-trace-kernel/20231208183601.GA46-beaub@linux.microsoft.com/
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 5eaf7f0589c0d88178f0fbeebe0e0b7108258707)
---
fs/tracefs/event_inode.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 0b90869fd805..43e237864a42 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -546,6 +546,8 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
if (strcmp(ei_child->name, name) != 0)
continue;
ret = simple_lookup(dir, dentry, flags);
+ if (IS_ERR(ret))
+ goto out;
create_dir_dentry(ei, ei_child, ei_dentry, true);
created = true;
break;
@@ -568,6 +570,8 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
if (r <= 0)
continue;
ret = simple_lookup(dir, dentry, flags);
+ if (IS_ERR(ret))
+ goto out;
create_file_dentry(ei, i, ei_dentry, name, mode, cdata,
fops, true);
break;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 31/57] eventfs: Have event files and directories default to parent uid and gid
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (29 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 30/57] eventfs: Fix events beyond NAME_MAX blocking tasks Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 32/57] eventfs: Fix file and directory uid and gid ownership Steven Rostedt
` (26 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Hongyu Jin,
Dongliang Cui
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Dongliang reported:
I found that in the latest version, the nodes of tracefs have been
changed to dynamically created.
This has caused me to encounter a problem where the gid I specified in
the mounting parameters cannot apply to all files, as in the following
situation:
/data/tmp/events # mount | grep tracefs
tracefs on /data/tmp type tracefs (rw,seclabel,relatime,gid=3012)
gid 3012 = readtracefs
/data/tmp # ls -lh
total 0
-r--r----- 1 root readtracefs 0 1970-01-01 08:00 README
-r--r----- 1 root readtracefs 0 1970-01-01 08:00 available_events
ums9621_1h10:/data/tmp/events # ls -lh
total 0
drwxr-xr-x 2 root root 0 2023-12-19 00:56 alarmtimer
drwxr-xr-x 2 root root 0 2023-12-19 00:56 asoc
It will prevent certain applications from accessing tracefs properly, I
try to avoid this issue by making the following modifications.
To fix this, have the files created default to taking the ownership of
the parent dentry unless the ownership was previously set by the user.
Link: https://lore.kernel.org/linux-trace-kernel/1703063706-30539-1-git-send-email-dongliang.cui@unisoc.com/
Link: https://lore.kernel.org/linux-trace-kernel/20231220105017.1489d790@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Hongyu Jin <hongyu.jin@unisoc.com>
Fixes: 28e12c09f5aa0 ("eventfs: Save ownership and mode")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reported-by: Dongliang Cui <cuidongliang390@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 0dfc852b6fe3cbecbea67332a0dce2bebeba540d)
---
fs/tracefs/event_inode.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 43e237864a42..2ccc849a5bda 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -148,7 +148,8 @@ static const struct file_operations eventfs_file_operations = {
.release = eventfs_release,
};
-static void update_inode_attr(struct inode *inode, struct eventfs_attr *attr, umode_t mode)
+static void update_inode_attr(struct dentry *dentry, struct inode *inode,
+ struct eventfs_attr *attr, umode_t mode)
{
if (!attr) {
inode->i_mode = mode;
@@ -162,9 +163,13 @@ static void update_inode_attr(struct inode *inode, struct eventfs_attr *attr, um
if (attr->mode & EVENTFS_SAVE_UID)
inode->i_uid = attr->uid;
+ else
+ inode->i_uid = d_inode(dentry->d_parent)->i_uid;
if (attr->mode & EVENTFS_SAVE_GID)
inode->i_gid = attr->gid;
+ else
+ inode->i_gid = d_inode(dentry->d_parent)->i_gid;
}
/**
@@ -206,7 +211,7 @@ static struct dentry *create_file(const char *name, umode_t mode,
return eventfs_failed_creating(dentry);
/* If the user updated the directory's attributes, use them */
- update_inode_attr(inode, attr, mode);
+ update_inode_attr(dentry, inode, attr, mode);
inode->i_op = &eventfs_file_inode_operations;
inode->i_fop = fop;
@@ -242,7 +247,8 @@ static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent
return eventfs_failed_creating(dentry);
/* If the user updated the directory's attributes, use them */
- update_inode_attr(inode, &ei->attr, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO);
+ update_inode_attr(dentry, inode, &ei->attr,
+ S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO);
inode->i_op = &eventfs_root_dir_inode_operations;
inode->i_fop = &eventfs_file_operations;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 32/57] eventfs: Fix file and directory uid and gid ownership
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (30 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 31/57] eventfs: Have event files and directories default to parent uid and gid Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 33/57] tracefs: Check for dentry->d_inode exists in set_gid() Steven Rostedt
` (25 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Dongliang Cui,
Hongyu Jin
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
It was reported that when mounting the tracefs file system with a gid
other than root, the ownership did not carry down to the eventfs directory
due to the dynamic nature of it.
A fix was done to solve this, but it had two issues.
(a) if the attr passed into update_inode_attr() was NULL, it didn't do
anything. This is true for files that have not had a chown or chgrp
done to itself or any of its sibling files, as the attr is allocated
for all children when any one needs it.
# umount /sys/kernel/tracing
# mount -o rw,seclabel,relatime,gid=1000 -t tracefs nodev /mnt
# ls -ld /mnt/events/sched
drwxr-xr-x 28 root rostedt 0 Dec 21 13:12 /mnt/events/sched/
# ls -ld /mnt/events/sched/sched_switch
drwxr-xr-x 2 root rostedt 0 Dec 21 13:12 /mnt/events/sched/sched_switch/
But when checking the files:
# ls -l /mnt/events/sched/sched_switch
total 0
-rw-r----- 1 root root 0 Dec 21 13:12 enable
-rw-r----- 1 root root 0 Dec 21 13:12 filter
-r--r----- 1 root root 0 Dec 21 13:12 format
-r--r----- 1 root root 0 Dec 21 13:12 hist
-r--r----- 1 root root 0 Dec 21 13:12 id
-rw-r----- 1 root root 0 Dec 21 13:12 trigger
(b) When the attr does not denote the UID or GID, it defaulted to using
the parent uid or gid. This is incorrect as changing the parent
uid or gid will automatically change all its children.
# chgrp tracing /mnt/events/timer
# ls -ld /mnt/events/timer
drwxr-xr-x 2 root tracing 0 Dec 21 14:34 /mnt/events/timer
# ls -l /mnt/events/timer
total 0
-rw-r----- 1 root root 0 Dec 21 14:35 enable
-rw-r----- 1 root root 0 Dec 21 14:35 filter
drwxr-xr-x 2 root tracing 0 Dec 21 14:35 hrtimer_cancel
drwxr-xr-x 2 root tracing 0 Dec 21 14:35 hrtimer_expire_entry
drwxr-xr-x 2 root tracing 0 Dec 21 14:35 hrtimer_expire_exit
drwxr-xr-x 2 root tracing 0 Dec 21 14:35 hrtimer_init
drwxr-xr-x 2 root tracing 0 Dec 21 14:35 hrtimer_start
drwxr-xr-x 2 root tracing 0 Dec 21 14:35 itimer_expire
drwxr-xr-x 2 root tracing 0 Dec 21 14:35 itimer_state
drwxr-xr-x 2 root tracing 0 Dec 21 14:35 tick_stop
drwxr-xr-x 2 root tracing 0 Dec 21 14:35 timer_cancel
drwxr-xr-x 2 root tracing 0 Dec 21 14:35 timer_expire_entry
drwxr-xr-x 2 root tracing 0 Dec 21 14:35 timer_expire_exit
drwxr-xr-x 2 root tracing 0 Dec 21 14:35 timer_init
drwxr-xr-x 2 root tracing 0 Dec 21 14:35 timer_start
At first it was thought that this could be easily fixed by just making the
default ownership of the superblock when it was mounted. But this does not
handle the case of:
# chgrp tracing instances
# mkdir instances/foo
If the superblock was used, then the group ownership would be that of what
it was when it was mounted, when it should instead be "tracing".
Instead, set a flag for the top level eventfs directory ("events") to flag
which eventfs_inode belongs to it.
Since the "events" directory's dentry and inode are never freed, it does
not need to use its attr field to restore its mode and ownership. Use the
this eventfs_inode's attr as the default ownership for all the files and
directories underneath it.
When the events eventfs_inode is created, it sets its ownership to its
parent uid and gid. As the events directory is created at boot up before
it gets mounted, this will always be uid=0 and gid=0. If it's created via
an instance, then it will take the ownership of the instance directory.
When the file system is mounted, it will update all the gids if one is
specified. This will have a callback to update the events evenfs_inode's
default entries.
When a file or directory is created under the events directory, it will
walk the ei->dentry parents until it finds the evenfs_inode that belongs
to the events directory to retrieve the default uid and gid values.
Link: https://lore.kernel.org/all/CAHk-=wiwQtUHvzwyZucDq8=Gtw+AnwScyLhpFswrQ84PjhoGsg@mail.gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20231221190757.7eddbca9@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Dongliang Cui <cuidongliang390@gmail.com>
Cc: Hongyu Jin <hongyu.jin@unisoc.com>
Fixes: 0dfc852b6fe3 ("eventfs: Have event files and directories default to parent uid and gid")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Tested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 7e8358edf503e87236c8d07f69ef0ed846dd5112)
---
fs/tracefs/event_inode.c | 105 +++++++++++++++++++++++++++++++++++----
fs/tracefs/inode.c | 6 +++
fs/tracefs/internal.h | 2 +
3 files changed, 103 insertions(+), 10 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 2ccc849a5bda..f0677ea0ec24 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -113,7 +113,14 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
* determined by the parent directory.
*/
if (dentry->d_inode->i_mode & S_IFDIR) {
- update_attr(&ei->attr, iattr);
+ /*
+ * The events directory dentry is never freed, unless its
+ * part of an instance that is deleted. It's attr is the
+ * default for its child files and directories.
+ * Do not update it. It's not used for its own mode or ownership
+ */
+ if (!ei->is_events)
+ update_attr(&ei->attr, iattr);
} else {
name = dentry->d_name.name;
@@ -148,28 +155,93 @@ static const struct file_operations eventfs_file_operations = {
.release = eventfs_release,
};
+/* Return the evenfs_inode of the "events" directory */
+static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
+{
+ struct eventfs_inode *ei;
+
+ mutex_lock(&eventfs_mutex);
+ do {
+ /* The parent always has an ei, except for events itself */
+ ei = dentry->d_parent->d_fsdata;
+
+ /*
+ * If the ei is being freed, the ownership of the children
+ * doesn't matter.
+ */
+ if (ei->is_freed) {
+ ei = NULL;
+ break;
+ }
+
+ dentry = ei->dentry;
+ } while (!ei->is_events);
+ mutex_unlock(&eventfs_mutex);
+
+ return ei;
+}
+
static void update_inode_attr(struct dentry *dentry, struct inode *inode,
struct eventfs_attr *attr, umode_t mode)
{
- if (!attr) {
- inode->i_mode = mode;
+ struct eventfs_inode *events_ei = eventfs_find_events(dentry);
+
+ if (!events_ei)
+ return;
+
+ inode->i_mode = mode;
+ inode->i_uid = events_ei->attr.uid;
+ inode->i_gid = events_ei->attr.gid;
+
+ if (!attr)
return;
- }
if (attr->mode & EVENTFS_SAVE_MODE)
inode->i_mode = attr->mode & EVENTFS_MODE_MASK;
- else
- inode->i_mode = mode;
if (attr->mode & EVENTFS_SAVE_UID)
inode->i_uid = attr->uid;
- else
- inode->i_uid = d_inode(dentry->d_parent)->i_uid;
if (attr->mode & EVENTFS_SAVE_GID)
inode->i_gid = attr->gid;
- else
- inode->i_gid = d_inode(dentry->d_parent)->i_gid;
+}
+
+static void update_gid(struct eventfs_inode *ei, kgid_t gid, int level)
+{
+ struct eventfs_inode *ei_child;
+
+ /* at most we have events/system/event */
+ if (WARN_ON_ONCE(level > 3))
+ return;
+
+ ei->attr.gid = gid;
+
+ if (ei->entry_attrs) {
+ for (int i = 0; i < ei->nr_entries; i++) {
+ ei->entry_attrs[i].gid = gid;
+ }
+ }
+
+ /*
+ * Only eventfs_inode with dentries are updated, make sure
+ * all eventfs_inodes are updated. If one of the children
+ * do not have a dentry, this function must traverse it.
+ */
+ list_for_each_entry_srcu(ei_child, &ei->children, list,
+ srcu_read_lock_held(&eventfs_srcu)) {
+ if (!ei_child->dentry)
+ update_gid(ei_child, gid, level + 1);
+ }
+}
+
+void eventfs_update_gid(struct dentry *dentry, kgid_t gid)
+{
+ struct eventfs_inode *ei = dentry->d_fsdata;
+ int idx;
+
+ idx = srcu_read_lock(&eventfs_srcu);
+ update_gid(ei, gid, 0);
+ srcu_read_unlock(&eventfs_srcu, idx);
}
/**
@@ -860,6 +932,8 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
struct eventfs_inode *ei;
struct tracefs_inode *ti;
struct inode *inode;
+ kuid_t uid;
+ kgid_t gid;
if (security_locked_down(LOCKDOWN_TRACEFS))
return NULL;
@@ -884,11 +958,20 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
ei->dentry = dentry;
ei->entries = entries;
ei->nr_entries = size;
+ ei->is_events = 1;
ei->data = data;
ei->name = kstrdup_const(name, GFP_KERNEL);
if (!ei->name)
goto fail;
+ /* Save the ownership of this directory */
+ uid = d_inode(dentry->d_parent)->i_uid;
+ gid = d_inode(dentry->d_parent)->i_gid;
+
+ /* This is used as the default ownership of the files and directories */
+ ei->attr.uid = uid;
+ ei->attr.gid = gid;
+
INIT_LIST_HEAD(&ei->children);
INIT_LIST_HEAD(&ei->list);
@@ -897,6 +980,8 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
ti->private = ei;
inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
+ inode->i_uid = uid;
+ inode->i_gid = gid;
inode->i_op = &eventfs_root_dir_inode_operations;
inode->i_fop = &eventfs_file_operations;
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index b9ed8db4f6b9..7b0ba379d6d7 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -210,6 +210,7 @@ static void set_gid(struct dentry *parent, kgid_t gid)
next = this_parent->d_subdirs.next;
resume:
while (next != &this_parent->d_subdirs) {
+ struct tracefs_inode *ti;
struct list_head *tmp = next;
struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
next = tmp->next;
@@ -218,6 +219,11 @@ static void set_gid(struct dentry *parent, kgid_t gid)
change_gid(dentry, gid);
+ /* If this is the events directory, update that too */
+ ti = get_tracefs(dentry->d_inode);
+ if (ti && (ti->flags & TRACEFS_EVENT_INODE))
+ eventfs_update_gid(dentry, gid);
+
if (!list_empty(&dentry->d_subdirs)) {
spin_unlock(&this_parent->d_lock);
spin_release(&dentry->d_lock.dep_map, _RET_IP_);
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index ccee18ca66c7..899e447778ac 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -62,6 +62,7 @@ struct eventfs_inode {
struct rcu_head rcu;
};
unsigned int is_freed:1;
+ unsigned int is_events:1;
unsigned int nr_entries:31;
};
@@ -77,6 +78,7 @@ struct inode *tracefs_get_inode(struct super_block *sb);
struct dentry *eventfs_start_creating(const char *name, struct dentry *parent);
struct dentry *eventfs_failed_creating(struct dentry *dentry);
struct dentry *eventfs_end_creating(struct dentry *dentry);
+void eventfs_update_gid(struct dentry *dentry, kgid_t gid);
void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry);
#endif /* _TRACEFS_INTERNAL_H */
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 33/57] tracefs: Check for dentry->d_inode exists in set_gid()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (31 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 32/57] eventfs: Fix file and directory uid and gid ownership Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 34/57] eventfs: Fix bitwise fields for "is_events" Steven Rostedt
` (24 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Ubisectech Sirius
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
If a getdents() is called on the tracefs directory but does not get all
the files, it can leave a "cursor" dentry in the d_subdirs list of tracefs
dentry. This cursor dentry does not have a d_inode for it. Before
referencing tracefs_inode from the dentry, the d_inode must first be
checked if it has content. If not, then it's not a tracefs_inode and can
be ignored.
The following caused a crash:
#define getdents64(fd, dirp, count) syscall(SYS_getdents64, fd, dirp, count)
#define BUF_SIZE 256
#define TDIR "/tmp/file0"
int main(void)
{
char buf[BUF_SIZE];
int fd;
int n;
mkdir(TDIR, 0777);
mount(NULL, TDIR, "tracefs", 0, NULL);
fd = openat(AT_FDCWD, TDIR, O_RDONLY);
n = getdents64(fd, buf, BUF_SIZE);
ret = mount(NULL, TDIR, NULL, MS_NOSUID|MS_REMOUNT|MS_RELATIME|MS_LAZYTIME,
"gid=1000");
return 0;
}
That's because the 256 BUF_SIZE was not big enough to read all the
dentries of the tracefs file system and it left a "cursor" dentry in the
subdirs of the tracefs root inode. Then on remounting with "gid=1000",
it would cause an iteration of all dentries which hit:
ti = get_tracefs(dentry->d_inode);
if (ti && (ti->flags & TRACEFS_EVENT_INODE))
eventfs_update_gid(dentry, gid);
Which crashed because of the dereference of the cursor dentry which had a NULL
d_inode.
In the subdir loop of the dentry lookup of set_gid(), if a child has a
NULL d_inode, simply skip it.
Link: https://lore.kernel.org/all/20240102135637.3a21fb10@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20240102151249.05da244d@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 7e8358edf503e ("eventfs: Fix file and directory uid and gid ownership")
Reported-by: "Ubisectech Sirius" <bugreport@ubisectech.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit ad579864637af46447208254719943179b69d41a)
---
fs/tracefs/inode.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index 7b0ba379d6d7..c27b0cfff70c 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -215,6 +215,10 @@ static void set_gid(struct dentry *parent, kgid_t gid)
struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
next = tmp->next;
+ /* Note, getdents() can add a cursor dentry with no inode */
+ if (!dentry->d_inode)
+ continue;
+
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
change_gid(dentry, gid);
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 34/57] eventfs: Fix bitwise fields for "is_events"
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (32 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 33/57] tracefs: Check for dentry->d_inode exists in set_gid() Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 35/57] eventfs: Remove "lookup" parameter from create_dir/file_dentry() Steven Rostedt
` (23 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
A flag was needed to denote which eventfs_inode was the "events"
directory, so a bit was taken from the "nr_entries" field, as there's not
that many entries, and 2^30 is plenty. But the bit number for nr_entries
was not updated to reflect the bit taken from it, which would add an
unnecessary integer to the structure.
Link: https://lore.kernel.org/linux-trace-kernel/20240102151832.7ca87275@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 7e8358edf503e ("eventfs: Fix file and directory uid and gid ownership")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit fd56cd5f6d76e93356d9520cf9dabffe1e3d1aa0)
---
fs/tracefs/internal.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 899e447778ac..42bdeb471a07 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -63,7 +63,7 @@ struct eventfs_inode {
};
unsigned int is_freed:1;
unsigned int is_events:1;
- unsigned int nr_entries:31;
+ unsigned int nr_entries:30;
};
static inline struct tracefs_inode *get_tracefs(const struct inode *inode)
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 35/57] eventfs: Remove "lookup" parameter from create_dir/file_dentry()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (33 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 34/57] eventfs: Fix bitwise fields for "is_events" Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 36/57] eventfs: Stop using dcache_readdir() for getdents() Steven Rostedt
` (22 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Ajay Kaher,
Al Viro, Christian Brauner
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The "lookup" parameter is a way to differentiate the call to
create_file/dir_dentry() from when it's just a lookup (no need to up the
dentry refcount) and accessed via a readdir (need to up the refcount).
But reality, it just makes the code more complex. Just up the refcount and
let the caller decide to dput() the result or not.
Link: https://lore.kernel.org/linux-trace-kernel/20240103102553.17a19cea@gandalf.local.home
Link: https://lore.kernel.org/linux-trace-kernel/20240104015435.517502710@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ajay Kaher <akaher@vmware.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit b0f7e2d739b4aac131ea1662d086a07775097b05)
---
fs/tracefs/event_inode.c | 55 +++++++++++++++-------------------------
1 file changed, 20 insertions(+), 35 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index f0677ea0ec24..c360300fb866 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -390,16 +390,14 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
* @mode: The mode of the file.
* @data: The data to use to set the inode of the file with on open()
* @fops: The fops of the file to be created.
- * @lookup: If called by the lookup routine, in which case, dput() the created dentry.
*
* Create a dentry for a file of an eventfs_inode @ei and place it into the
- * address located at @e_dentry. If the @e_dentry already has a dentry, then
- * just do a dget() on it and return. Otherwise create the dentry and attach it.
+ * address located at @e_dentry.
*/
static struct dentry *
create_file_dentry(struct eventfs_inode *ei, int idx,
struct dentry *parent, const char *name, umode_t mode, void *data,
- const struct file_operations *fops, bool lookup)
+ const struct file_operations *fops)
{
struct eventfs_attr *attr = NULL;
struct dentry **e_dentry = &ei->d_children[idx];
@@ -414,9 +412,7 @@ create_file_dentry(struct eventfs_inode *ei, int idx,
}
/* If the e_dentry already has a dentry, use it */
if (*e_dentry) {
- /* lookup does not need to up the ref count */
- if (!lookup)
- dget(*e_dentry);
+ dget(*e_dentry);
mutex_unlock(&eventfs_mutex);
return *e_dentry;
}
@@ -441,13 +437,12 @@ create_file_dentry(struct eventfs_inode *ei, int idx,
* way to being freed, don't return it. If e_dentry is NULL
* it means it was already freed.
*/
- if (ei->is_freed)
+ if (ei->is_freed) {
dentry = NULL;
- else
+ } else {
dentry = *e_dentry;
- /* The lookup does not need to up the dentry refcount */
- if (dentry && !lookup)
dget(dentry);
+ }
mutex_unlock(&eventfs_mutex);
return dentry;
}
@@ -465,9 +460,6 @@ create_file_dentry(struct eventfs_inode *ei, int idx,
}
mutex_unlock(&eventfs_mutex);
- if (lookup)
- dput(dentry);
-
return dentry;
}
@@ -500,13 +492,12 @@ static void eventfs_post_create_dir(struct eventfs_inode *ei)
* @pei: The eventfs_inode parent of ei.
* @ei: The eventfs_inode to create the directory for
* @parent: The dentry of the parent of this directory
- * @lookup: True if this is called by the lookup code
*
* This creates and attaches a directory dentry to the eventfs_inode @ei.
*/
static struct dentry *
create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
- struct dentry *parent, bool lookup)
+ struct dentry *parent)
{
struct dentry *dentry = NULL;
@@ -518,11 +509,9 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
return NULL;
}
if (ei->dentry) {
- /* If the dentry already has a dentry, use it */
+ /* If the eventfs_inode already has a dentry, use it */
dentry = ei->dentry;
- /* lookup does not need to up the ref count */
- if (!lookup)
- dget(dentry);
+ dget(dentry);
mutex_unlock(&eventfs_mutex);
return dentry;
}
@@ -542,7 +531,7 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
* way to being freed.
*/
dentry = ei->dentry;
- if (dentry && !lookup)
+ if (dentry)
dget(dentry);
mutex_unlock(&eventfs_mutex);
return dentry;
@@ -562,9 +551,6 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
}
mutex_unlock(&eventfs_mutex);
- if (lookup)
- dput(dentry);
-
return dentry;
}
@@ -589,8 +575,8 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
struct eventfs_inode *ei;
struct dentry *ei_dentry = NULL;
struct dentry *ret = NULL;
+ struct dentry *d;
const char *name = dentry->d_name.name;
- bool created = false;
umode_t mode;
void *data;
int idx;
@@ -626,13 +612,10 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
ret = simple_lookup(dir, dentry, flags);
if (IS_ERR(ret))
goto out;
- create_dir_dentry(ei, ei_child, ei_dentry, true);
- created = true;
- break;
- }
-
- if (created)
+ d = create_dir_dentry(ei, ei_child, ei_dentry);
+ dput(d);
goto out;
+ }
for (i = 0; i < ei->nr_entries; i++) {
entry = &ei->entries[i];
@@ -650,8 +633,8 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
ret = simple_lookup(dir, dentry, flags);
if (IS_ERR(ret))
goto out;
- create_file_dentry(ei, i, ei_dentry, name, mode, cdata,
- fops, true);
+ d = create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops);
+ dput(d);
break;
}
}
@@ -768,9 +751,10 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
inode_lock(parent->d_inode);
list_for_each_entry_srcu(ei_child, &ei->children, list,
srcu_read_lock_held(&eventfs_srcu)) {
- d = create_dir_dentry(ei, ei_child, parent, false);
+ d = create_dir_dentry(ei, ei_child, parent);
if (d) {
ret = add_dentries(&dentries, d, cnt);
+ dput(d);
if (ret < 0)
break;
cnt++;
@@ -790,9 +774,10 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
mutex_unlock(&eventfs_mutex);
if (r <= 0)
continue;
- d = create_file_dentry(ei, i, parent, name, mode, cdata, fops, false);
+ d = create_file_dentry(ei, i, parent, name, mode, cdata, fops);
if (d) {
ret = add_dentries(&dentries, d, cnt);
+ dput(d);
if (ret < 0)
break;
cnt++;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 36/57] eventfs: Stop using dcache_readdir() for getdents()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (34 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 35/57] eventfs: Remove "lookup" parameter from create_dir/file_dentry() Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 37/57] tracefs/eventfs: Use root and instance inodes as default ownership Steven Rostedt
` (21 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Ajay Kaher,
Al Viro, Christian Brauner
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The eventfs creates dynamically allocated dentries and inodes. Using the
dcache_readdir() logic for its own directory lookups requires hiding the
cursor of the dcache logic and playing games to allow the dcache_readdir()
to still have access to the cursor while the eventfs saved what it created
and what it needs to release.
Instead, just have eventfs have its own iterate_shared callback function
that will fill in the dent entries. This simplifies the code quite a bit.
Link: https://lore.kernel.org/linux-trace-kernel/20240104015435.682218477@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ajay Kaher <akaher@vmware.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 493ec81a8fb8e4ada6f223b8b73791a1280d4774)
---
fs/tracefs/event_inode.c | 194 +++++++++++++--------------------------
1 file changed, 64 insertions(+), 130 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index c360300fb866..41af56f44f0a 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -52,9 +52,7 @@ enum {
static struct dentry *eventfs_root_lookup(struct inode *dir,
struct dentry *dentry,
unsigned int flags);
-static int dcache_dir_open_wrapper(struct inode *inode, struct file *file);
-static int dcache_readdir_wrapper(struct file *file, struct dir_context *ctx);
-static int eventfs_release(struct inode *inode, struct file *file);
+static int eventfs_iterate(struct file *file, struct dir_context *ctx);
static void update_attr(struct eventfs_attr *attr, struct iattr *iattr)
{
@@ -148,11 +146,9 @@ static const struct inode_operations eventfs_file_inode_operations = {
};
static const struct file_operations eventfs_file_operations = {
- .open = dcache_dir_open_wrapper,
.read = generic_read_dir,
- .iterate_shared = dcache_readdir_wrapper,
+ .iterate_shared = eventfs_iterate,
.llseek = generic_file_llseek,
- .release = eventfs_release,
};
/* Return the evenfs_inode of the "events" directory */
@@ -643,128 +639,87 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
return ret;
}
-struct dentry_list {
- void *cursor;
- struct dentry **dentries;
-};
-
-/**
- * eventfs_release - called to release eventfs file/dir
- * @inode: inode to be released
- * @file: file to be released (not used)
- */
-static int eventfs_release(struct inode *inode, struct file *file)
-{
- struct tracefs_inode *ti;
- struct dentry_list *dlist = file->private_data;
- void *cursor;
- int i;
-
- ti = get_tracefs(inode);
- if (!(ti->flags & TRACEFS_EVENT_INODE))
- return -EINVAL;
-
- if (WARN_ON_ONCE(!dlist))
- return -EINVAL;
-
- for (i = 0; dlist->dentries && dlist->dentries[i]; i++) {
- dput(dlist->dentries[i]);
- }
-
- cursor = dlist->cursor;
- kfree(dlist->dentries);
- kfree(dlist);
- file->private_data = cursor;
- return dcache_dir_close(inode, file);
-}
-
-static int add_dentries(struct dentry ***dentries, struct dentry *d, int cnt)
-{
- struct dentry **tmp;
-
- tmp = krealloc(*dentries, sizeof(d) * (cnt + 2), GFP_NOFS);
- if (!tmp)
- return -1;
- tmp[cnt] = d;
- tmp[cnt + 1] = NULL;
- *dentries = tmp;
- return 0;
-}
-
-/**
- * dcache_dir_open_wrapper - eventfs open wrapper
- * @inode: not used
- * @file: dir to be opened (to create it's children)
- *
- * Used to dynamic create file/dir with-in @file, all the
- * file/dir will be created. If already created then references
- * will be increased
+/*
+ * Walk the children of a eventfs_inode to fill in getdents().
*/
-static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
+static int eventfs_iterate(struct file *file, struct dir_context *ctx)
{
const struct file_operations *fops;
+ struct inode *f_inode = file_inode(file);
const struct eventfs_entry *entry;
struct eventfs_inode *ei_child;
struct tracefs_inode *ti;
struct eventfs_inode *ei;
- struct dentry_list *dlist;
- struct dentry **dentries = NULL;
- struct dentry *parent = file_dentry(file);
- struct dentry *d;
- struct inode *f_inode = file_inode(file);
- const char *name = parent->d_name.name;
+ struct dentry *ei_dentry = NULL;
+ struct dentry *dentry;
+ const char *name;
umode_t mode;
- void *data;
- int cnt = 0;
int idx;
- int ret;
- int i;
- int r;
+ int ret = -EINVAL;
+ int ino;
+ int i, r, c;
+
+ if (!dir_emit_dots(file, ctx))
+ return 0;
ti = get_tracefs(f_inode);
if (!(ti->flags & TRACEFS_EVENT_INODE))
return -EINVAL;
- if (WARN_ON_ONCE(file->private_data))
- return -EINVAL;
+ c = ctx->pos - 2;
idx = srcu_read_lock(&eventfs_srcu);
mutex_lock(&eventfs_mutex);
ei = READ_ONCE(ti->private);
+ if (ei && !ei->is_freed)
+ ei_dentry = READ_ONCE(ei->dentry);
mutex_unlock(&eventfs_mutex);
- if (!ei) {
- srcu_read_unlock(&eventfs_srcu, idx);
- return -EINVAL;
- }
-
-
- data = ei->data;
+ if (!ei || !ei_dentry)
+ goto out;
- dlist = kmalloc(sizeof(*dlist), GFP_KERNEL);
- if (!dlist) {
- srcu_read_unlock(&eventfs_srcu, idx);
- return -ENOMEM;
- }
+ ret = 0;
- inode_lock(parent->d_inode);
+ /*
+ * Need to create the dentries and inodes to have a consistent
+ * inode number.
+ */
list_for_each_entry_srcu(ei_child, &ei->children, list,
srcu_read_lock_held(&eventfs_srcu)) {
- d = create_dir_dentry(ei, ei_child, parent);
- if (d) {
- ret = add_dentries(&dentries, d, cnt);
- dput(d);
- if (ret < 0)
- break;
- cnt++;
+
+ if (c > 0) {
+ c--;
+ continue;
}
+
+ if (ei_child->is_freed)
+ continue;
+
+ name = ei_child->name;
+
+ dentry = create_dir_dentry(ei, ei_child, ei_dentry);
+ if (!dentry)
+ goto out;
+ ino = dentry->d_inode->i_ino;
+ dput(dentry);
+
+ if (!dir_emit(ctx, name, strlen(name), ino, DT_DIR))
+ goto out;
+ ctx->pos++;
}
for (i = 0; i < ei->nr_entries; i++) {
- void *cdata = data;
+ void *cdata = ei->data;
+
+ if (c > 0) {
+ c--;
+ continue;
+ }
+
entry = &ei->entries[i];
name = entry->name;
+
mutex_lock(&eventfs_mutex);
/* If ei->is_freed, then the event itself may be too */
if (!ei->is_freed)
@@ -774,42 +729,21 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
mutex_unlock(&eventfs_mutex);
if (r <= 0)
continue;
- d = create_file_dentry(ei, i, parent, name, mode, cdata, fops);
- if (d) {
- ret = add_dentries(&dentries, d, cnt);
- dput(d);
- if (ret < 0)
- break;
- cnt++;
- }
- }
- inode_unlock(parent->d_inode);
- srcu_read_unlock(&eventfs_srcu, idx);
- ret = dcache_dir_open(inode, file);
- /*
- * dcache_dir_open() sets file->private_data to a dentry cursor.
- * Need to save that but also save all the dentries that were
- * opened by this function.
- */
- dlist->cursor = file->private_data;
- dlist->dentries = dentries;
- file->private_data = dlist;
- return ret;
-}
+ dentry = create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops);
+ if (!dentry)
+ goto out;
+ ino = dentry->d_inode->i_ino;
+ dput(dentry);
-/*
- * This just sets the file->private_data back to the cursor and back.
- */
-static int dcache_readdir_wrapper(struct file *file, struct dir_context *ctx)
-{
- struct dentry_list *dlist = file->private_data;
- int ret;
+ if (!dir_emit(ctx, name, strlen(name), ino, DT_REG))
+ goto out;
+ ctx->pos++;
+ }
+ ret = 1;
+ out:
+ srcu_read_unlock(&eventfs_srcu, idx);
- file->private_data = dlist->cursor;
- ret = dcache_readdir(file, ctx);
- dlist->cursor = file->private_data;
- file->private_data = dlist;
return ret;
}
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 37/57] tracefs/eventfs: Use root and instance inodes as default ownership
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (35 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 36/57] eventfs: Stop using dcache_readdir() for getdents() Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 38/57] eventfs: Have eventfs_iterate() stop immediately if ei->is_freed is set Steven Rostedt
` (20 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Al Viro,
Christian Brauner
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Instead of walking the dentries on mount/remount to update the gid values of
all the dentries if a gid option is specified on mount, just update the root
inode. Add .getattr, .setattr, and .permissions on the tracefs inode
operations to update the permissions of the files and directories.
For all files and directories in the top level instance:
/sys/kernel/tracing/*
It will use the root inode as the default permissions. The inode that
represents: /sys/kernel/tracing (or wherever it is mounted).
When an instance is created:
mkdir /sys/kernel/tracing/instance/foo
The directory "foo" and all its files and directories underneath will use
the default of what foo is when it was created. A remount of tracefs will
not affect it.
If a user were to modify the permissions of any file or directory in
tracefs, it will also no longer be modified by a change in ownership of a
remount.
The events directory, if it is in the top level instance, will use the
tracefs root inode as the default ownership for itself and all the files and
directories below it.
For the events directory in an instance ("foo"), it will keep the ownership
of what it was when it was created, and that will be used as the default
ownership for the files and directories beneath it.
Link: https://lore.kernel.org/linux-trace-kernel/CAHk-=wjVdGkjDXBbvLn2wbZnqP4UsH46E3gqJ9m7UG6DpX2+WA@mail.gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240103215016.1e0c9811@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 8186fff7ab649085e2c60d032d9a20a85af1d87c)
---
fs/tracefs/event_inode.c | 79 +++++++++++++++-
fs/tracefs/inode.c | 198 ++++++++++++++++++++++-----------------
fs/tracefs/internal.h | 3 +
3 files changed, 190 insertions(+), 90 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 41af56f44f0a..72912b5f9a90 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -45,6 +45,7 @@ enum {
EVENTFS_SAVE_MODE = BIT(16),
EVENTFS_SAVE_UID = BIT(17),
EVENTFS_SAVE_GID = BIT(18),
+ EVENTFS_TOPLEVEL = BIT(19),
};
#define EVENTFS_MODE_MASK (EVENTFS_SAVE_MODE - 1)
@@ -115,10 +116,17 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
* The events directory dentry is never freed, unless its
* part of an instance that is deleted. It's attr is the
* default for its child files and directories.
- * Do not update it. It's not used for its own mode or ownership
+ * Do not update it. It's not used for its own mode or ownership.
*/
- if (!ei->is_events)
+ if (ei->is_events) {
+ /* But it still needs to know if it was modified */
+ if (iattr->ia_valid & ATTR_UID)
+ ei->attr.mode |= EVENTFS_SAVE_UID;
+ if (iattr->ia_valid & ATTR_GID)
+ ei->attr.mode |= EVENTFS_SAVE_GID;
+ } else {
update_attr(&ei->attr, iattr);
+ }
} else {
name = dentry->d_name.name;
@@ -136,9 +144,66 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
return ret;
}
+static void update_top_events_attr(struct eventfs_inode *ei, struct dentry *dentry)
+{
+ struct inode *inode;
+
+ /* Only update if the "events" was on the top level */
+ if (!ei || !(ei->attr.mode & EVENTFS_TOPLEVEL))
+ return;
+
+ /* Get the tracefs root inode. */
+ inode = d_inode(dentry->d_sb->s_root);
+ ei->attr.uid = inode->i_uid;
+ ei->attr.gid = inode->i_gid;
+}
+
+static void set_top_events_ownership(struct inode *inode)
+{
+ struct tracefs_inode *ti = get_tracefs(inode);
+ struct eventfs_inode *ei = ti->private;
+ struct dentry *dentry;
+
+ /* The top events directory doesn't get automatically updated */
+ if (!ei || !ei->is_events || !(ei->attr.mode & EVENTFS_TOPLEVEL))
+ return;
+
+ dentry = ei->dentry;
+
+ update_top_events_attr(ei, dentry);
+
+ if (!(ei->attr.mode & EVENTFS_SAVE_UID))
+ inode->i_uid = ei->attr.uid;
+
+ if (!(ei->attr.mode & EVENTFS_SAVE_GID))
+ inode->i_gid = ei->attr.gid;
+}
+
+static int eventfs_get_attr(struct mnt_idmap *idmap,
+ const struct path *path, struct kstat *stat,
+ u32 request_mask, unsigned int flags)
+{
+ struct dentry *dentry = path->dentry;
+ struct inode *inode = d_backing_inode(dentry);
+
+ set_top_events_ownership(inode);
+
+ generic_fillattr(idmap, request_mask, inode, stat);
+ return 0;
+}
+
+static int eventfs_permission(struct mnt_idmap *idmap,
+ struct inode *inode, int mask)
+{
+ set_top_events_ownership(inode);
+ return generic_permission(idmap, inode, mask);
+}
+
static const struct inode_operations eventfs_root_dir_inode_operations = {
.lookup = eventfs_root_lookup,
.setattr = eventfs_set_attr,
+ .getattr = eventfs_get_attr,
+ .permission = eventfs_permission,
};
static const struct inode_operations eventfs_file_inode_operations = {
@@ -174,6 +239,8 @@ static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
} while (!ei->is_events);
mutex_unlock(&eventfs_mutex);
+ update_top_events_attr(ei, dentry);
+
return ei;
}
@@ -887,6 +954,14 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
uid = d_inode(dentry->d_parent)->i_uid;
gid = d_inode(dentry->d_parent)->i_gid;
+ /*
+ * If the events directory is of the top instance, then parent
+ * is NULL. Set the attr.mode to reflect this and its permissions will
+ * default to the tracefs root dentry.
+ */
+ if (!parent)
+ ei->attr.mode = EVENTFS_TOPLEVEL;
+
/* This is used as the default ownership of the files and directories */
ei->attr.uid = uid;
ei->attr.gid = gid;
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index c27b0cfff70c..fc0f133eefdb 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -91,6 +91,7 @@ static int tracefs_syscall_mkdir(struct mnt_idmap *idmap,
struct inode *inode, struct dentry *dentry,
umode_t mode)
{
+ struct tracefs_inode *ti;
char *name;
int ret;
@@ -98,6 +99,15 @@ static int tracefs_syscall_mkdir(struct mnt_idmap *idmap,
if (!name)
return -ENOMEM;
+ /*
+ * This is a new directory that does not take the default of
+ * the rootfs. It becomes the default permissions for all the
+ * files and directories underneath it.
+ */
+ ti = get_tracefs(inode);
+ ti->flags |= TRACEFS_INSTANCE_INODE;
+ ti->private = inode;
+
/*
* The mkdir call can call the generic functions that create
* the files within the tracefs system. It is up to the individual
@@ -141,10 +151,76 @@ static int tracefs_syscall_rmdir(struct inode *inode, struct dentry *dentry)
return ret;
}
-static const struct inode_operations tracefs_dir_inode_operations = {
+static void set_tracefs_inode_owner(struct inode *inode)
+{
+ struct tracefs_inode *ti = get_tracefs(inode);
+ struct inode *root_inode = ti->private;
+
+ /*
+ * If this inode has never been referenced, then update
+ * the permissions to the superblock.
+ */
+ if (!(ti->flags & TRACEFS_UID_PERM_SET))
+ inode->i_uid = root_inode->i_uid;
+
+ if (!(ti->flags & TRACEFS_GID_PERM_SET))
+ inode->i_gid = root_inode->i_gid;
+}
+
+static int tracefs_permission(struct mnt_idmap *idmap,
+ struct inode *inode, int mask)
+{
+ set_tracefs_inode_owner(inode);
+ return generic_permission(idmap, inode, mask);
+}
+
+static int tracefs_getattr(struct mnt_idmap *idmap,
+ const struct path *path, struct kstat *stat,
+ u32 request_mask, unsigned int flags)
+{
+ struct inode *inode = d_backing_inode(path->dentry);
+
+ set_tracefs_inode_owner(inode);
+ generic_fillattr(idmap, request_mask, inode, stat);
+ return 0;
+}
+
+static int tracefs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ struct iattr *attr)
+{
+ unsigned int ia_valid = attr->ia_valid;
+ struct inode *inode = d_inode(dentry);
+ struct tracefs_inode *ti = get_tracefs(inode);
+
+ if (ia_valid & ATTR_UID)
+ ti->flags |= TRACEFS_UID_PERM_SET;
+
+ if (ia_valid & ATTR_GID)
+ ti->flags |= TRACEFS_GID_PERM_SET;
+
+ return simple_setattr(idmap, dentry, attr);
+}
+
+static const struct inode_operations tracefs_instance_dir_inode_operations = {
.lookup = simple_lookup,
.mkdir = tracefs_syscall_mkdir,
.rmdir = tracefs_syscall_rmdir,
+ .permission = tracefs_permission,
+ .getattr = tracefs_getattr,
+ .setattr = tracefs_setattr,
+};
+
+static const struct inode_operations tracefs_dir_inode_operations = {
+ .lookup = simple_lookup,
+ .permission = tracefs_permission,
+ .getattr = tracefs_getattr,
+ .setattr = tracefs_setattr,
+};
+
+static const struct inode_operations tracefs_file_inode_operations = {
+ .permission = tracefs_permission,
+ .getattr = tracefs_getattr,
+ .setattr = tracefs_setattr,
};
struct inode *tracefs_get_inode(struct super_block *sb)
@@ -183,87 +259,6 @@ struct tracefs_fs_info {
struct tracefs_mount_opts mount_opts;
};
-static void change_gid(struct dentry *dentry, kgid_t gid)
-{
- if (!dentry->d_inode)
- return;
- dentry->d_inode->i_gid = gid;
-}
-
-/*
- * Taken from d_walk, but without he need for handling renames.
- * Nothing can be renamed while walking the list, as tracefs
- * does not support renames. This is only called when mounting
- * or remounting the file system, to set all the files to
- * the given gid.
- */
-static void set_gid(struct dentry *parent, kgid_t gid)
-{
- struct dentry *this_parent;
- struct list_head *next;
-
- this_parent = parent;
- spin_lock(&this_parent->d_lock);
-
- change_gid(this_parent, gid);
-repeat:
- next = this_parent->d_subdirs.next;
-resume:
- while (next != &this_parent->d_subdirs) {
- struct tracefs_inode *ti;
- struct list_head *tmp = next;
- struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
- next = tmp->next;
-
- /* Note, getdents() can add a cursor dentry with no inode */
- if (!dentry->d_inode)
- continue;
-
- spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
-
- change_gid(dentry, gid);
-
- /* If this is the events directory, update that too */
- ti = get_tracefs(dentry->d_inode);
- if (ti && (ti->flags & TRACEFS_EVENT_INODE))
- eventfs_update_gid(dentry, gid);
-
- if (!list_empty(&dentry->d_subdirs)) {
- spin_unlock(&this_parent->d_lock);
- spin_release(&dentry->d_lock.dep_map, _RET_IP_);
- this_parent = dentry;
- spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_);
- goto repeat;
- }
- spin_unlock(&dentry->d_lock);
- }
- /*
- * All done at this level ... ascend and resume the search.
- */
- rcu_read_lock();
-ascend:
- if (this_parent != parent) {
- struct dentry *child = this_parent;
- this_parent = child->d_parent;
-
- spin_unlock(&child->d_lock);
- spin_lock(&this_parent->d_lock);
-
- /* go into the first sibling still alive */
- do {
- next = child->d_child.next;
- if (next == &this_parent->d_subdirs)
- goto ascend;
- child = list_entry(next, struct dentry, d_child);
- } while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
- rcu_read_unlock();
- goto resume;
- }
- rcu_read_unlock();
- spin_unlock(&this_parent->d_lock);
- return;
-}
-
static int tracefs_parse_options(char *data, struct tracefs_mount_opts *opts)
{
substring_t args[MAX_OPT_ARGS];
@@ -336,10 +331,8 @@ static int tracefs_apply_options(struct super_block *sb, bool remount)
if (!remount || opts->opts & BIT(Opt_uid))
inode->i_uid = opts->uid;
- if (!remount || opts->opts & BIT(Opt_gid)) {
- /* Set all the group ids to the mount option */
- set_gid(sb->s_root, opts->gid);
- }
+ if (!remount || opts->opts & BIT(Opt_gid))
+ inode->i_gid = opts->gid;
return 0;
}
@@ -573,6 +566,26 @@ struct dentry *eventfs_end_creating(struct dentry *dentry)
return dentry;
}
+/* Find the inode that this will use for default */
+static struct inode *instance_inode(struct dentry *parent, struct inode *inode)
+{
+ struct tracefs_inode *ti;
+
+ /* If parent is NULL then use root inode */
+ if (!parent)
+ return d_inode(inode->i_sb->s_root);
+
+ /* Find the inode that is flagged as an instance or the root inode */
+ while (!IS_ROOT(parent)) {
+ ti = get_tracefs(d_inode(parent));
+ if (ti->flags & TRACEFS_INSTANCE_INODE)
+ break;
+ parent = parent->d_parent;
+ }
+
+ return d_inode(parent);
+}
+
/**
* tracefs_create_file - create a file in the tracefs filesystem
* @name: a pointer to a string containing the name of the file to create.
@@ -603,6 +616,7 @@ struct dentry *tracefs_create_file(const char *name, umode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fops)
{
+ struct tracefs_inode *ti;
struct dentry *dentry;
struct inode *inode;
@@ -621,7 +635,11 @@ struct dentry *tracefs_create_file(const char *name, umode_t mode,
if (unlikely(!inode))
return tracefs_failed_creating(dentry);
+ ti = get_tracefs(inode);
+ ti->private = instance_inode(parent, inode);
+
inode->i_mode = mode;
+ inode->i_op = &tracefs_file_inode_operations;
inode->i_fop = fops ? fops : &tracefs_file_operations;
inode->i_private = data;
inode->i_uid = d_inode(dentry->d_parent)->i_uid;
@@ -634,6 +652,7 @@ struct dentry *tracefs_create_file(const char *name, umode_t mode,
static struct dentry *__create_dir(const char *name, struct dentry *parent,
const struct inode_operations *ops)
{
+ struct tracefs_inode *ti;
struct dentry *dentry = tracefs_start_creating(name, parent);
struct inode *inode;
@@ -651,6 +670,9 @@ static struct dentry *__create_dir(const char *name, struct dentry *parent,
inode->i_uid = d_inode(dentry->d_parent)->i_uid;
inode->i_gid = d_inode(dentry->d_parent)->i_gid;
+ ti = get_tracefs(inode);
+ ti->private = instance_inode(parent, inode);
+
/* directory inodes start off with i_nlink == 2 (for "." entry) */
inc_nlink(inode);
d_instantiate(dentry, inode);
@@ -681,7 +703,7 @@ struct dentry *tracefs_create_dir(const char *name, struct dentry *parent)
if (security_locked_down(LOCKDOWN_TRACEFS))
return NULL;
- return __create_dir(name, parent, &simple_dir_inode_operations);
+ return __create_dir(name, parent, &tracefs_dir_inode_operations);
}
/**
@@ -712,7 +734,7 @@ __init struct dentry *tracefs_create_instance_dir(const char *name,
if (WARN_ON(tracefs_ops.mkdir || tracefs_ops.rmdir))
return NULL;
- dentry = __create_dir(name, parent, &tracefs_dir_inode_operations);
+ dentry = __create_dir(name, parent, &tracefs_instance_dir_inode_operations);
if (!dentry)
return NULL;
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 42bdeb471a07..12b7d0150ae9 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -5,6 +5,9 @@
enum {
TRACEFS_EVENT_INODE = BIT(1),
TRACEFS_EVENT_TOP_INODE = BIT(2),
+ TRACEFS_GID_PERM_SET = BIT(3),
+ TRACEFS_UID_PERM_SET = BIT(4),
+ TRACEFS_INSTANCE_INODE = BIT(5),
};
struct tracefs_inode {
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 38/57] eventfs: Have eventfs_iterate() stop immediately if ei->is_freed is set
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (36 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 37/57] tracefs/eventfs: Use root and instance inodes as default ownership Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 39/57] eventfs: Do ctx->pos update for all iterations in eventfs_iterate() Steven Rostedt
` (19 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Al Viro, Christian Brauner
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
If ei->is_freed is set in eventfs_iterate(), it means that the directory
that is being iterated on is in the process of being freed. Just exit the
loop immediately when that is ever detected, and separate out the return
of the entry->callback() from ei->is_freed.
Link: https://lore.kernel.org/linux-trace-kernel/20240104220048.016261289@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit e109deadb73318cf4a3bd61287d969f705df278f)
---
fs/tracefs/event_inode.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 72912b5f9a90..0aca6910efb3 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -788,11 +788,12 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
name = entry->name;
mutex_lock(&eventfs_mutex);
- /* If ei->is_freed, then the event itself may be too */
- if (!ei->is_freed)
- r = entry->callback(name, &mode, &cdata, &fops);
- else
- r = -1;
+ /* If ei->is_freed then just bail here, nothing more to do */
+ if (ei->is_freed) {
+ mutex_unlock(&eventfs_mutex);
+ goto out;
+ }
+ r = entry->callback(name, &mode, &cdata, &fops);
mutex_unlock(&eventfs_mutex);
if (r <= 0)
continue;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 39/57] eventfs: Do ctx->pos update for all iterations in eventfs_iterate()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (37 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 38/57] eventfs: Have eventfs_iterate() stop immediately if ei->is_freed is set Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 40/57] eventfs: Read ei->entries before ei->children " Steven Rostedt
` (18 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Al Viro, Christian Brauner
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The ctx->pos was only updated when it added an entry, but the "skip to
current pos" check (c--) happened for every loop regardless of if the
entry was added or not. This inconsistency caused readdir to be incorrect.
It was due to:
for (i = 0; i < ei->nr_entries; i++) {
if (c > 0) {
c--;
continue;
}
mutex_lock(&eventfs_mutex);
/* If ei->is_freed then just bail here, nothing more to do */
if (ei->is_freed) {
mutex_unlock(&eventfs_mutex);
goto out;
}
r = entry->callback(name, &mode, &cdata, &fops);
mutex_unlock(&eventfs_mutex);
[..]
ctx->pos++;
}
But this can cause the iterator to return a file that was already read.
That's because of the way the callback() works. Some events may not have
all files, and the callback can return 0 to tell eventfs to skip the file
for this directory.
for instance, we have:
# ls /sys/kernel/tracing/events/ftrace/function
format hist hist_debug id inject
and
# ls /sys/kernel/tracing/events/sched/sched_switch/
enable filter format hist hist_debug id inject trigger
Where the function directory is missing "enable", "filter" and
"trigger". That's because the callback() for events has:
static int event_callback(const char *name, umode_t *mode, void **data,
const struct file_operations **fops)
{
struct trace_event_file *file = *data;
struct trace_event_call *call = file->event_call;
[..]
/*
* Only event directories that can be enabled should have
* triggers or filters, with the exception of the "print"
* event that can have a "trigger" file.
*/
if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) {
if (call->class->reg && strcmp(name, "enable") == 0) {
*mode = TRACE_MODE_WRITE;
*fops = &ftrace_enable_fops;
return 1;
}
if (strcmp(name, "filter") == 0) {
*mode = TRACE_MODE_WRITE;
*fops = &ftrace_event_filter_fops;
return 1;
}
}
if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE) ||
strcmp(trace_event_name(call), "print") == 0) {
if (strcmp(name, "trigger") == 0) {
*mode = TRACE_MODE_WRITE;
*fops = &event_trigger_fops;
return 1;
}
}
[..]
return 0;
}
Where the function event has the TRACE_EVENT_FL_IGNORE_ENABLE set.
This means that the entries array elements for "enable", "filter" and
"trigger" when called on the function event will have the callback return
0 and not 1, to tell eventfs to skip these files for it.
Because the "skip to current ctx->pos" check happened for all entries, but
the ctx->pos++ only happened to entries that exist, it would confuse the
reading of a directory. Which would cause:
# ls /sys/kernel/tracing/events/ftrace/function/
format hist hist hist_debug hist_debug id inject inject
The missing "enable", "filter" and "trigger" caused ls to show "hist",
"hist_debug" and "inject" twice.
Update the ctx->pos for every iteration to keep its update and the "skip"
update consistent. This also means that on error, the ctx->pos needs to be
decremented if it was incremented without adding something.
Link: https://lore.kernel.org/all/20240104150500.38b15a62@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20240104220048.172295263@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: 493ec81a8fb8e ("eventfs: Stop using dcache_readdir() for getdents()")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 1e4624eb5a0ecaae0d2c4e3019bece119725bb98)
---
fs/tracefs/event_inode.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 0aca6910efb3..c73fb1f7ddbc 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -760,6 +760,8 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
continue;
}
+ ctx->pos++;
+
if (ei_child->is_freed)
continue;
@@ -767,13 +769,12 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
dentry = create_dir_dentry(ei, ei_child, ei_dentry);
if (!dentry)
- goto out;
+ goto out_dec;
ino = dentry->d_inode->i_ino;
dput(dentry);
if (!dir_emit(ctx, name, strlen(name), ino, DT_DIR))
- goto out;
- ctx->pos++;
+ goto out_dec;
}
for (i = 0; i < ei->nr_entries; i++) {
@@ -784,6 +785,8 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
continue;
}
+ ctx->pos++;
+
entry = &ei->entries[i];
name = entry->name;
@@ -791,7 +794,7 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
/* If ei->is_freed then just bail here, nothing more to do */
if (ei->is_freed) {
mutex_unlock(&eventfs_mutex);
- goto out;
+ goto out_dec;
}
r = entry->callback(name, &mode, &cdata, &fops);
mutex_unlock(&eventfs_mutex);
@@ -800,19 +803,23 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
dentry = create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops);
if (!dentry)
- goto out;
+ goto out_dec;
ino = dentry->d_inode->i_ino;
dput(dentry);
if (!dir_emit(ctx, name, strlen(name), ino, DT_REG))
- goto out;
- ctx->pos++;
+ goto out_dec;
}
ret = 1;
out:
srcu_read_unlock(&eventfs_srcu, idx);
return ret;
+
+ out_dec:
+ /* Incremented ctx->pos without adding something, reset it */
+ ctx->pos--;
+ goto out;
}
/**
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 40/57] eventfs: Read ei->entries before ei->children in eventfs_iterate()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (38 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 39/57] eventfs: Do ctx->pos update for all iterations in eventfs_iterate() Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 41/57] eventfs: Shortcut eventfs_iterate() by skipping entries already read Steven Rostedt
` (17 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Al Viro, Christian Brauner
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
In order to apply a shortcut to skip over the current ctx->pos
immediately, by using the ei->entries array, the reading of that array
should be first. Moving the array reading before the linked list reading
will make the shortcut change diff nicer to read.
Link: https://lore.kernel.org/all/CAHk-=wiKwDUDv3+jCsv-uacDcHDVTYsXtBR9=6sGM5mqX+DhOg@mail.gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240104220048.333115095@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 704f960dbee2f1634f4b4e16f208cb16eaf41c1e)
---
fs/tracefs/event_inode.c | 46 ++++++++++++++++++++--------------------
1 file changed, 23 insertions(+), 23 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index c73fb1f7ddbc..a1934e0eea3b 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -752,8 +752,8 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
* Need to create the dentries and inodes to have a consistent
* inode number.
*/
- list_for_each_entry_srcu(ei_child, &ei->children, list,
- srcu_read_lock_held(&eventfs_srcu)) {
+ for (i = 0; i < ei->nr_entries; i++) {
+ void *cdata = ei->data;
if (c > 0) {
c--;
@@ -762,23 +762,32 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
ctx->pos++;
- if (ei_child->is_freed)
- continue;
+ entry = &ei->entries[i];
+ name = entry->name;
- name = ei_child->name;
+ mutex_lock(&eventfs_mutex);
+ /* If ei->is_freed then just bail here, nothing more to do */
+ if (ei->is_freed) {
+ mutex_unlock(&eventfs_mutex);
+ goto out_dec;
+ }
+ r = entry->callback(name, &mode, &cdata, &fops);
+ mutex_unlock(&eventfs_mutex);
+ if (r <= 0)
+ continue;
- dentry = create_dir_dentry(ei, ei_child, ei_dentry);
+ dentry = create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops);
if (!dentry)
goto out_dec;
ino = dentry->d_inode->i_ino;
dput(dentry);
- if (!dir_emit(ctx, name, strlen(name), ino, DT_DIR))
+ if (!dir_emit(ctx, name, strlen(name), ino, DT_REG))
goto out_dec;
}
- for (i = 0; i < ei->nr_entries; i++) {
- void *cdata = ei->data;
+ list_for_each_entry_srcu(ei_child, &ei->children, list,
+ srcu_read_lock_held(&eventfs_srcu)) {
if (c > 0) {
c--;
@@ -787,27 +796,18 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
ctx->pos++;
- entry = &ei->entries[i];
- name = entry->name;
-
- mutex_lock(&eventfs_mutex);
- /* If ei->is_freed then just bail here, nothing more to do */
- if (ei->is_freed) {
- mutex_unlock(&eventfs_mutex);
- goto out_dec;
- }
- r = entry->callback(name, &mode, &cdata, &fops);
- mutex_unlock(&eventfs_mutex);
- if (r <= 0)
+ if (ei_child->is_freed)
continue;
- dentry = create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops);
+ name = ei_child->name;
+
+ dentry = create_dir_dentry(ei, ei_child, ei_dentry);
if (!dentry)
goto out_dec;
ino = dentry->d_inode->i_ino;
dput(dentry);
- if (!dir_emit(ctx, name, strlen(name), ino, DT_REG))
+ if (!dir_emit(ctx, name, strlen(name), ino, DT_DIR))
goto out_dec;
}
ret = 1;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 41/57] eventfs: Shortcut eventfs_iterate() by skipping entries already read
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (39 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 40/57] eventfs: Read ei->entries before ei->children " Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 42/57] eventfs: Have the inodes all for files and directories all be the same Steven Rostedt
` (16 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton,
Al Viro, Christian Brauner
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
As the ei->entries array is fixed for the duration of the eventfs_inode,
it can be used to skip over already read entries in eventfs_iterate().
That is, if ctx->pos is greater than zero, there's no reason in doing the
loop across the ei->entries array for the entries less than ctx->pos.
Instead, start the lookup of the entries at the current ctx->pos.
Link: https://lore.kernel.org/all/CAHk-=wiKwDUDv3+jCsv-uacDcHDVTYsXtBR9=6sGM5mqX+DhOg@mail.gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240104220048.494956957@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 1de94b52d5e8d8b32f0252f14fad1f1edc2e71f1)
---
fs/tracefs/event_inode.c | 23 ++++++++++-------------
1 file changed, 10 insertions(+), 13 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index a1934e0eea3b..fdff53d5a1f8 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -746,21 +746,15 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
if (!ei || !ei_dentry)
goto out;
- ret = 0;
-
/*
* Need to create the dentries and inodes to have a consistent
* inode number.
*/
- for (i = 0; i < ei->nr_entries; i++) {
- void *cdata = ei->data;
-
- if (c > 0) {
- c--;
- continue;
- }
+ ret = 0;
- ctx->pos++;
+ /* Start at 'c' to jump over already read entries */
+ for (i = c; i < ei->nr_entries; i++, ctx->pos++) {
+ void *cdata = ei->data;
entry = &ei->entries[i];
name = entry->name;
@@ -769,7 +763,7 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
/* If ei->is_freed then just bail here, nothing more to do */
if (ei->is_freed) {
mutex_unlock(&eventfs_mutex);
- goto out_dec;
+ goto out;
}
r = entry->callback(name, &mode, &cdata, &fops);
mutex_unlock(&eventfs_mutex);
@@ -778,14 +772,17 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
dentry = create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops);
if (!dentry)
- goto out_dec;
+ goto out;
ino = dentry->d_inode->i_ino;
dput(dentry);
if (!dir_emit(ctx, name, strlen(name), ino, DT_REG))
- goto out_dec;
+ goto out;
}
+ /* Subtract the skipped entries above */
+ c -= min((unsigned int)c, (unsigned int)ei->nr_entries);
+
list_for_each_entry_srcu(ei_child, &ei->children, list,
srcu_read_lock_held(&eventfs_srcu)) {
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 42/57] eventfs: Have the inodes all for files and directories all be the same
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (40 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 41/57] eventfs: Shortcut eventfs_iterate() by skipping entries already read Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 43/57] eventfs: Do not create dentries nor inodes in iterate_shared Steven Rostedt
` (15 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Christian Brauner, Al Viro, Ajay Kaher
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The dentries and inodes are created in the readdir for the sole purpose of
getting a consistent inode number. Linus stated that is unnecessary, and
that all inodes can have the same inode number. For a virtual file system
they are pretty meaningless.
Instead use a single unique inode number for all files and one for all
directories.
Link: https://lore.kernel.org/all/20240116133753.2808d45e@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20240116211353.412180363@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 53c41052ba3121761e6f62a813961164532a214f)
---
fs/tracefs/event_inode.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index fdff53d5a1f8..5edf0b96758b 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -32,6 +32,10 @@
*/
static DEFINE_MUTEX(eventfs_mutex);
+/* Choose something "unique" ;-) */
+#define EVENTFS_FILE_INODE_INO 0x12c4e37
+#define EVENTFS_DIR_INODE_INO 0x134b2f5
+
/*
* The eventfs_inode (ei) itself is protected by SRCU. It is released from
* its parent's list and will have is_freed set (under eventfs_mutex).
@@ -352,6 +356,9 @@ static struct dentry *create_file(const char *name, umode_t mode,
inode->i_fop = fop;
inode->i_private = data;
+ /* All files will have the same inode number */
+ inode->i_ino = EVENTFS_FILE_INODE_INO;
+
ti = get_tracefs(inode);
ti->flags |= TRACEFS_EVENT_INODE;
d_instantiate(dentry, inode);
@@ -388,6 +395,9 @@ static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent
inode->i_op = &eventfs_root_dir_inode_operations;
inode->i_fop = &eventfs_file_operations;
+ /* All directories will have the same inode number */
+ inode->i_ino = EVENTFS_DIR_INODE_INO;
+
ti = get_tracefs(inode);
ti->flags |= TRACEFS_EVENT_INODE;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 43/57] eventfs: Do not create dentries nor inodes in iterate_shared
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (41 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 42/57] eventfs: Have the inodes all for files and directories all be the same Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 44/57] eventfs: Use kcalloc() instead of kzalloc() Steven Rostedt
` (14 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Christian Brauner, Al Viro, Ajay Kaher, kernel test robot
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The original eventfs code added a wrapper around the dcache_readdir open
callback and created all the dentries and inodes at open, and increment
their ref count. A wrapper was added around the dcache_readdir release
function to decrement all the ref counts of those created inodes and
dentries. But this proved to be buggy[1] for when a kprobe was created
during a dir read, it would create a dentry between the open and the
release, and because the release would decrement all ref counts of all
files and directories, that would include the kprobe directory that was
not there to have its ref count incremented in open. This would cause the
ref count to go to negative and later crash the kernel.
To solve this, the dentries and inodes that were created and had their ref
count upped in open needed to be saved. That list needed to be passed from
the open to the release, so that the release would only decrement the ref
counts of the entries that were incremented in the open.
Unfortunately, the dcache_readdir logic was already using the
file->private_data, which is the only field that can be used to pass
information from the open to the release. What was done was the eventfs
created another descriptor that had a void pointer to save the
dcache_readdir pointer, and it wrapped all the callbacks, so that it could
save the list of entries that had their ref counts incremented in the
open, and pass it to the release. The wrapped callbacks would just put
back the dcache_readdir pointer and call the functions it used so it could
still use its data[2].
But Linus had an issue with the "hijacking" of the file->private_data
(unfortunately this discussion was on a security list, so no public link).
Which we finally agreed on doing everything within the iterate_shared
callback and leave the dcache_readdir out of it[3]. All the information
needed for the getents() could be created then.
But this ended up being buggy too[4]. The iterate_shared callback was not
the right place to create the dentries and inodes. Even Christian Brauner
had issues with that[5].
An attempt was to go back to creating the inodes and dentries at
the open, create an array to store the information in the
file->private_data, and pass that information to the other callbacks.[6]
The difference between that and the original method, is that it does not
use dcache_readdir. It also does not up the ref counts of the dentries and
pass them. Instead, it creates an array of a structure that saves the
dentry's name and inode number. That information is used in the
iterate_shared callback, and the array is freed in the dir release. The
dentries and inodes created in the open are not used for the iterate_share
or release callbacks. Just their names and inode numbers.
Linus did not like that either[7] and just wanted to remove the dentries
being created in iterate_shared and use the hard coded inode numbers.
[ All this while Linus enjoyed an unexpected vacation during the merge
window due to lack of power. ]
[1] https://lore.kernel.org/linux-trace-kernel/20230919211804.230edf1e@gandalf.local.home/
[2] https://lore.kernel.org/linux-trace-kernel/20230922163446.1431d4fa@gandalf.local.home/
[3] https://lore.kernel.org/linux-trace-kernel/20240104015435.682218477@goodmis.org/
[4] https://lore.kernel.org/all/202401152142.bfc28861-oliver.sang@intel.com/
[5] https://lore.kernel.org/all/20240111-unzahl-gefegt-433acb8a841d@brauner/
[6] https://lore.kernel.org/all/20240116114711.7e8637be@gandalf.local.home/
[7] https://lore.kernel.org/all/20240116170154.5bf0a250@gandalf.local.home/
Link: https://lore.kernel.org/linux-trace-kernel/20240116211353.573784051@goodmis.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Fixes: 493ec81a8fb8 ("eventfs: Stop using dcache_readdir() for getdents()")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202401152142.bfc28861-oliver.sang@intel.com
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 852e46e239ee6db3cd220614cf8bce96e79227c2)
---
fs/tracefs/event_inode.c | 20 +++++---------------
1 file changed, 5 insertions(+), 15 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 5edf0b96758b..10580d6b5012 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -727,8 +727,6 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
struct eventfs_inode *ei_child;
struct tracefs_inode *ti;
struct eventfs_inode *ei;
- struct dentry *ei_dentry = NULL;
- struct dentry *dentry;
const char *name;
umode_t mode;
int idx;
@@ -749,11 +747,11 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
mutex_lock(&eventfs_mutex);
ei = READ_ONCE(ti->private);
- if (ei && !ei->is_freed)
- ei_dentry = READ_ONCE(ei->dentry);
+ if (ei && ei->is_freed)
+ ei = NULL;
mutex_unlock(&eventfs_mutex);
- if (!ei || !ei_dentry)
+ if (!ei)
goto out;
/*
@@ -780,11 +778,7 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
if (r <= 0)
continue;
- dentry = create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops);
- if (!dentry)
- goto out;
- ino = dentry->d_inode->i_ino;
- dput(dentry);
+ ino = EVENTFS_FILE_INODE_INO;
if (!dir_emit(ctx, name, strlen(name), ino, DT_REG))
goto out;
@@ -808,11 +802,7 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
name = ei_child->name;
- dentry = create_dir_dentry(ei, ei_child, ei_dentry);
- if (!dentry)
- goto out_dec;
- ino = dentry->d_inode->i_ino;
- dput(dentry);
+ ino = EVENTFS_DIR_INODE_INO;
if (!dir_emit(ctx, name, strlen(name), ino, DT_DIR))
goto out_dec;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 44/57] eventfs: Use kcalloc() instead of kzalloc()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (42 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 43/57] eventfs: Do not create dentries nor inodes in iterate_shared Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 45/57] eventfs: Save directory inodes in the eventfs_inode structure Steven Rostedt
` (13 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Erick Archer,
Gustavo A. R. Silva
From: Erick Archer <erick.archer@gmx.com>
As noted in the "Deprecated Interfaces, Language Features, Attributes,
and Conventions" documentation [1], size calculations (especially
multiplication) should not be performed in memory allocator (or similar)
function arguments due to the risk of them overflowing. This could lead
to values wrapping around and a smaller allocation being made than the
caller was expecting. Using those allocations could lead to linear
overflows of heap memory and other misbehaviors.
So, use the purpose specific kcalloc() function instead of the argument
size * count in the kzalloc() function.
[1] https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments
Link: https://lore.kernel.org/linux-trace-kernel/20240115181658.4562-1-erick.archer@gmx.com
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Link: https://github.com/KSPP/linux/issues/162
Signed-off-by: Erick Archer <erick.archer@gmx.com>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 1057066009c4325bb1d8430c9274894d0860e7c3)
---
fs/tracefs/event_inode.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 10580d6b5012..6795fda2af19 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -97,7 +97,7 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
/* Preallocate the children mode array if necessary */
if (!(dentry->d_inode->i_mode & S_IFDIR)) {
if (!ei->entry_attrs) {
- ei->entry_attrs = kzalloc(sizeof(*ei->entry_attrs) * ei->nr_entries,
+ ei->entry_attrs = kcalloc(ei->nr_entries, sizeof(*ei->entry_attrs),
GFP_NOFS);
if (!ei->entry_attrs) {
ret = -ENOMEM;
@@ -874,7 +874,7 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode
}
if (size) {
- ei->d_children = kzalloc(sizeof(*ei->d_children) * size, GFP_KERNEL);
+ ei->d_children = kcalloc(size, sizeof(*ei->d_children), GFP_KERNEL);
if (!ei->d_children) {
kfree_const(ei->name);
kfree(ei);
@@ -941,7 +941,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
goto fail;
if (size) {
- ei->d_children = kzalloc(sizeof(*ei->d_children) * size, GFP_KERNEL);
+ ei->d_children = kcalloc(size, sizeof(*ei->d_children), GFP_KERNEL);
if (!ei->d_children)
goto fail;
}
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 45/57] eventfs: Save directory inodes in the eventfs_inode structure
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (43 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 44/57] eventfs: Use kcalloc() instead of kzalloc() Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 46/57] tracefs: remove stale update_gid code Steven Rostedt
` (12 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Geert Uytterhoeven, Geert Uytterhoeven, Kees Cook
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The eventfs inodes and directories are allocated when referenced. But this
leaves the issue of keeping consistent inode numbers and the number is
only saved in the inode structure itself. When the inode is no longer
referenced, it can be freed. When the file that the inode was representing
is referenced again, the inode is once again created, but the inode number
needs to be the same as it was before.
Just making the inode numbers the same for all files is fine, but that
does not work with directories. The find command will check for loops via
the inode number and having the same inode number for directories triggers:
# find /sys/kernel/tracing
find: File system loop detected;
'/sys/kernel/debug/tracing/events/initcall/initcall_finish' is part of the same file system loop as
'/sys/kernel/debug/tracing/events/initcall'.
[..]
Linus pointed out that the eventfs_inode structure ends with a single
32bit int, and on 64 bit machines, there's likely a 4 byte hole due to
alignment. We can use this hole to store the inode number for the
eventfs_inode. All directories in eventfs are represented by an
eventfs_inode and that data structure can hold its inode number.
That last int was also purposely placed at the end of the structure to
prevent holes from within. Now that there's a 4 byte number to hold the
inode, both the inode number and the last integer can be moved up in the
structure for better cache locality, where the llist and rcu fields can be
moved to the end as they are only used when the eventfs_inode is being
deleted.
Link: https://lore.kernel.org/all/CAMuHMdXKiorg-jiuKoZpfZyDJ3Ynrfb8=X+c7x0Eewxn-YRdCA@mail.gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240122152748.46897388@gandalf.local.home
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Fixes: 53c41052ba31 ("eventfs: Have the inodes all for files and directories all be the same")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
(cherry picked from commit 834bf76add3e6168038150f162cbccf1fd492a67)
---
fs/tracefs/event_inode.c | 14 +++++++++++---
fs/tracefs/internal.h | 7 ++++---
2 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 6795fda2af19..6b211522a13e 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -34,7 +34,15 @@ static DEFINE_MUTEX(eventfs_mutex);
/* Choose something "unique" ;-) */
#define EVENTFS_FILE_INODE_INO 0x12c4e37
-#define EVENTFS_DIR_INODE_INO 0x134b2f5
+
+/* Just try to make something consistent and unique */
+static int eventfs_dir_ino(struct eventfs_inode *ei)
+{
+ if (!ei->ino)
+ ei->ino = get_next_ino();
+
+ return ei->ino;
+}
/*
* The eventfs_inode (ei) itself is protected by SRCU. It is released from
@@ -396,7 +404,7 @@ static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent
inode->i_fop = &eventfs_file_operations;
/* All directories will have the same inode number */
- inode->i_ino = EVENTFS_DIR_INODE_INO;
+ inode->i_ino = eventfs_dir_ino(ei);
ti = get_tracefs(inode);
ti->flags |= TRACEFS_EVENT_INODE;
@@ -802,7 +810,7 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
name = ei_child->name;
- ino = EVENTFS_DIR_INODE_INO;
+ ino = eventfs_dir_ino(ei_child);
if (!dir_emit(ctx, name, strlen(name), ino, DT_DIR))
goto out_dec;
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 12b7d0150ae9..45397df9bb65 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -55,6 +55,10 @@ struct eventfs_inode {
struct eventfs_attr *entry_attrs;
struct eventfs_attr attr;
void *data;
+ unsigned int is_freed:1;
+ unsigned int is_events:1;
+ unsigned int nr_entries:30;
+ unsigned int ino;
/*
* Union - used for deletion
* @llist: for calling dput() if needed after RCU
@@ -64,9 +68,6 @@ struct eventfs_inode {
struct llist_node llist;
struct rcu_head rcu;
};
- unsigned int is_freed:1;
- unsigned int is_events:1;
- unsigned int nr_entries:30;
};
static inline struct tracefs_inode *get_tracefs(const struct inode *inode)
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 46/57] tracefs: remove stale update_gid code
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (44 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 45/57] eventfs: Save directory inodes in the eventfs_inode structure Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 47/57] tracefs: Zero out the tracefs_inode when allocating it Steven Rostedt
` (11 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
From: Linus Torvalds <torvalds@linux-foundation.org>
The 'eventfs_update_gid()' function is no longer called, so remove it
(and the helper function it uses).
Link: https://lore.kernel.org/all/CAHk-=wj+DsZZ=2iTUkJ-Nojs9fjYMvPs1NuoM3yK7aTDtJfPYQ@mail.gmail.com/
Fixes: 8186fff7ab64 ("tracefs/eventfs: Use root and instance inodes as default ownership")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 29142dc92c37d3259a33aef15b03e6ee25b0d188)
---
fs/tracefs/event_inode.c | 38 --------------------------------------
fs/tracefs/internal.h | 1 -
2 files changed, 39 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 6b211522a13e..1c3dd0ad4660 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -281,44 +281,6 @@ static void update_inode_attr(struct dentry *dentry, struct inode *inode,
inode->i_gid = attr->gid;
}
-static void update_gid(struct eventfs_inode *ei, kgid_t gid, int level)
-{
- struct eventfs_inode *ei_child;
-
- /* at most we have events/system/event */
- if (WARN_ON_ONCE(level > 3))
- return;
-
- ei->attr.gid = gid;
-
- if (ei->entry_attrs) {
- for (int i = 0; i < ei->nr_entries; i++) {
- ei->entry_attrs[i].gid = gid;
- }
- }
-
- /*
- * Only eventfs_inode with dentries are updated, make sure
- * all eventfs_inodes are updated. If one of the children
- * do not have a dentry, this function must traverse it.
- */
- list_for_each_entry_srcu(ei_child, &ei->children, list,
- srcu_read_lock_held(&eventfs_srcu)) {
- if (!ei_child->dentry)
- update_gid(ei_child, gid, level + 1);
- }
-}
-
-void eventfs_update_gid(struct dentry *dentry, kgid_t gid)
-{
- struct eventfs_inode *ei = dentry->d_fsdata;
- int idx;
-
- idx = srcu_read_lock(&eventfs_srcu);
- update_gid(ei, gid, 0);
- srcu_read_unlock(&eventfs_srcu, idx);
-}
-
/**
* create_file - create a file in the tracefs filesystem
* @name: the name of the file to create.
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 45397df9bb65..91c2bf0b91d9 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -82,7 +82,6 @@ struct inode *tracefs_get_inode(struct super_block *sb);
struct dentry *eventfs_start_creating(const char *name, struct dentry *parent);
struct dentry *eventfs_failed_creating(struct dentry *dentry);
struct dentry *eventfs_end_creating(struct dentry *dentry);
-void eventfs_update_gid(struct dentry *dentry, kgid_t gid);
void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry);
#endif /* _TRACEFS_INTERNAL_H */
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 47/57] tracefs: Zero out the tracefs_inode when allocating it
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (45 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 46/57] tracefs: remove stale update_gid code Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 48/57] eventfs: Initialize the tracefs inode properly Steven Rostedt
` (10 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Christian Brauner, Al Viro, Ajay Kaher, kernel test robot
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
eventfs uses the tracefs_inode and assumes that it's already initialized
to zero. That is, it doesn't set fields to zero (like ti->private) after
getting its tracefs_inode. This causes bugs due to stale values.
Just initialize the entire structure to zero on allocation so there isn't
any more surprises.
This is a partial fix to access to ti->private. The assignment still needs
to be made before the dentry is instantiated.
Link: https://lore.kernel.org/linux-trace-kernel/20240131185512.315825944@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202401291043.e62e89dc-oliver.sang@intel.com
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit d81786f53aec14fd4d56263145a0635afbc64617)
---
fs/tracefs/inode.c | 6 ++++--
fs/tracefs/internal.h | 3 ++-
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index fc0f133eefdb..ad4c137b7be9 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -38,8 +38,6 @@ static struct inode *tracefs_alloc_inode(struct super_block *sb)
if (!ti)
return NULL;
- ti->flags = 0;
-
return &ti->vfs_inode;
}
@@ -779,7 +777,11 @@ static void init_once(void *foo)
{
struct tracefs_inode *ti = (struct tracefs_inode *) foo;
+ /* inode_init_once() calls memset() on the vfs_inode portion */
inode_init_once(&ti->vfs_inode);
+
+ /* Zero out the rest */
+ memset_after(ti, 0, vfs_inode);
}
static int __init tracefs_init(void)
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 91c2bf0b91d9..7d84349ade87 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -11,9 +11,10 @@ enum {
};
struct tracefs_inode {
+ struct inode vfs_inode;
+ /* The below gets initialized with memset_after(ti, 0, vfs_inode) */
unsigned long flags;
void *private;
- struct inode vfs_inode;
};
/*
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 48/57] eventfs: Initialize the tracefs inode properly
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (46 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 47/57] tracefs: Zero out the tracefs_inode when allocating it Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 49/57] tracefs: Avoid using the ei->dentry pointer unnecessarily Steven Rostedt
` (9 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Christian Brauner, Al Viro, Ajay Kaher, kernel test robot
From: Linus Torvalds <torvalds@linux-foundation.org>
The tracefs-specific fields in the inode were not initialized before the
inode was exposed to others through the dentry with 'd_instantiate()'.
Move the field initializations up to before the d_instantiate.
Link: https://lore.kernel.org/linux-trace-kernel/20240131185512.478449628@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202401291043.e62e89dc-oliver.sang@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 4fa4b010b83fb2f837b5ef79e38072a79e96e4f1)
---
fs/tracefs/event_inode.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 1c3dd0ad4660..824b1811e342 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -370,6 +370,8 @@ static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent
ti = get_tracefs(inode);
ti->flags |= TRACEFS_EVENT_INODE;
+ /* Only directories have ti->private set to an ei, not files */
+ ti->private = ei;
inc_nlink(inode);
d_instantiate(dentry, inode);
@@ -515,7 +517,6 @@ create_file_dentry(struct eventfs_inode *ei, int idx,
static void eventfs_post_create_dir(struct eventfs_inode *ei)
{
struct eventfs_inode *ei_child;
- struct tracefs_inode *ti;
lockdep_assert_held(&eventfs_mutex);
@@ -525,9 +526,6 @@ static void eventfs_post_create_dir(struct eventfs_inode *ei)
srcu_read_lock_held(&eventfs_srcu)) {
ei_child->d_parent = ei->dentry;
}
-
- ti = get_tracefs(ei->dentry->d_inode);
- ti->private = ei;
}
/**
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 49/57] tracefs: Avoid using the ei->dentry pointer unnecessarily
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (47 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 48/57] eventfs: Initialize the tracefs inode properly Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 50/57] tracefs: dentry lookup crapectomy Steven Rostedt
` (8 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Christian Brauner, Al Viro, Ajay Kaher
From: Linus Torvalds <torvalds@linux-foundation.org>
The eventfs_find_events() code tries to walk up the tree to find the
event directory that a dentry belongs to, in order to then find the
eventfs inode that is associated with that event directory.
However, it uses an odd combination of walking the dentry parent,
looking up the eventfs inode associated with that, and then looking up
the dentry from there. Repeat.
But the code shouldn't have back-pointers to dentries in the first
place, and it should just walk the dentry parenthood chain directly.
Similarly, 'set_top_events_ownership()' looks up the dentry from the
eventfs inode, but the only reason it wants a dentry is to look up the
superblock in order to look up the root dentry.
But it already has the real filesystem inode, which has that same
superblock pointer. So just pass in the superblock pointer using the
information that's already there, instead of looking up extraneous data
that is irrelevant.
Link: https://lore.kernel.org/linux-trace-kernel/202401291043.e62e89dc-oliver.sang@intel.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240131185512.638645365@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: c1504e510238 ("eventfs: Implement eventfs dir creation functions")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 99c001cb617df409dac275a059d6c3f187a2da7a)
---
fs/tracefs/event_inode.c | 26 ++++++++++++--------------
1 file changed, 12 insertions(+), 14 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 824b1811e342..e9819d719d2a 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -156,33 +156,30 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
return ret;
}
-static void update_top_events_attr(struct eventfs_inode *ei, struct dentry *dentry)
+static void update_top_events_attr(struct eventfs_inode *ei, struct super_block *sb)
{
- struct inode *inode;
+ struct inode *root;
/* Only update if the "events" was on the top level */
if (!ei || !(ei->attr.mode & EVENTFS_TOPLEVEL))
return;
/* Get the tracefs root inode. */
- inode = d_inode(dentry->d_sb->s_root);
- ei->attr.uid = inode->i_uid;
- ei->attr.gid = inode->i_gid;
+ root = d_inode(sb->s_root);
+ ei->attr.uid = root->i_uid;
+ ei->attr.gid = root->i_gid;
}
static void set_top_events_ownership(struct inode *inode)
{
struct tracefs_inode *ti = get_tracefs(inode);
struct eventfs_inode *ei = ti->private;
- struct dentry *dentry;
/* The top events directory doesn't get automatically updated */
if (!ei || !ei->is_events || !(ei->attr.mode & EVENTFS_TOPLEVEL))
return;
- dentry = ei->dentry;
-
- update_top_events_attr(ei, dentry);
+ update_top_events_attr(ei, inode->i_sb);
if (!(ei->attr.mode & EVENTFS_SAVE_UID))
inode->i_uid = ei->attr.uid;
@@ -235,8 +232,10 @@ static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
mutex_lock(&eventfs_mutex);
do {
- /* The parent always has an ei, except for events itself */
- ei = dentry->d_parent->d_fsdata;
+ // The parent is stable because we do not do renames
+ dentry = dentry->d_parent;
+ // ... and directories always have d_fsdata
+ ei = dentry->d_fsdata;
/*
* If the ei is being freed, the ownership of the children
@@ -246,12 +245,11 @@ static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
ei = NULL;
break;
}
-
- dentry = ei->dentry;
+ // Walk upwards until you find the events inode
} while (!ei->is_events);
mutex_unlock(&eventfs_mutex);
- update_top_events_attr(ei, dentry);
+ update_top_events_attr(ei, dentry->d_sb);
return ei;
}
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 50/57] tracefs: dentry lookup crapectomy
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (48 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 49/57] tracefs: Avoid using the ei->dentry pointer unnecessarily Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 51/57] eventfs: Remove unused d_parent pointer field Steven Rostedt
` (7 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Al Viro,
Christian Brauner, Ajay Kaher
From: Linus Torvalds <torvalds@linux-foundation.org>
The dentry lookup for eventfs files was very broken, and had lots of
signs of the old situation where the filesystem names were all created
statically in the dentry tree, rather than being looked up dynamically
based on the eventfs data structures.
You could see it in the naming - how it claimed to "create" dentries
rather than just look up the dentries that were given it.
You could see it in various nonsensical and very incorrect operations,
like using "simple_lookup()" on the dentries that were passed in, which
only results in those dentries becoming negative dentries. Which meant
that any other lookup would possibly return ENOENT if it saw that
negative dentry before the data was then later filled in.
You could see it in the immense amount of nonsensical code that didn't
actually just do lookups.
Link: https://lore.kernel.org/linux-trace-kernel/202401291043.e62e89dc-oliver.sang@intel.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240131233227.73db55e1@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Fixes: c1504e510238 ("eventfs: Implement eventfs dir creation functions")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 49304c2b93e4f7468b51ef717cbe637981397115)
---
fs/tracefs/event_inode.c | 275 +++++++--------------------------------
fs/tracefs/inode.c | 69 ----------
fs/tracefs/internal.h | 3 -
3 files changed, 50 insertions(+), 297 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index e9819d719d2a..04c2ab90f93e 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -230,7 +230,6 @@ static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
{
struct eventfs_inode *ei;
- mutex_lock(&eventfs_mutex);
do {
// The parent is stable because we do not do renames
dentry = dentry->d_parent;
@@ -247,7 +246,6 @@ static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
}
// Walk upwards until you find the events inode
} while (!ei->is_events);
- mutex_unlock(&eventfs_mutex);
update_top_events_attr(ei, dentry->d_sb);
@@ -280,11 +278,10 @@ static void update_inode_attr(struct dentry *dentry, struct inode *inode,
}
/**
- * create_file - create a file in the tracefs filesystem
- * @name: the name of the file to create.
+ * lookup_file - look up a file in the tracefs filesystem
+ * @dentry: the dentry to look up
* @mode: the permission that the file should have.
* @attr: saved attributes changed by user
- * @parent: parent dentry for this file.
* @data: something that the caller will want to get to later on.
* @fop: struct file_operations that should be used for this file.
*
@@ -292,13 +289,13 @@ static void update_inode_attr(struct dentry *dentry, struct inode *inode,
* directory. The inode.i_private pointer will point to @data in the open()
* call.
*/
-static struct dentry *create_file(const char *name, umode_t mode,
+static struct dentry *lookup_file(struct dentry *dentry,
+ umode_t mode,
struct eventfs_attr *attr,
- struct dentry *parent, void *data,
+ void *data,
const struct file_operations *fop)
{
struct tracefs_inode *ti;
- struct dentry *dentry;
struct inode *inode;
if (!(mode & S_IFMT))
@@ -307,15 +304,9 @@ static struct dentry *create_file(const char *name, umode_t mode,
if (WARN_ON_ONCE(!S_ISREG(mode)))
return NULL;
- WARN_ON_ONCE(!parent);
- dentry = eventfs_start_creating(name, parent);
-
- if (IS_ERR(dentry))
- return dentry;
-
inode = tracefs_get_inode(dentry->d_sb);
if (unlikely(!inode))
- return eventfs_failed_creating(dentry);
+ return ERR_PTR(-ENOMEM);
/* If the user updated the directory's attributes, use them */
update_inode_attr(dentry, inode, attr, mode);
@@ -329,32 +320,29 @@ static struct dentry *create_file(const char *name, umode_t mode,
ti = get_tracefs(inode);
ti->flags |= TRACEFS_EVENT_INODE;
- d_instantiate(dentry, inode);
+
+ d_add(dentry, inode);
fsnotify_create(dentry->d_parent->d_inode, dentry);
- return eventfs_end_creating(dentry);
+ return dentry;
};
/**
- * create_dir - create a dir in the tracefs filesystem
+ * lookup_dir_entry - look up a dir in the tracefs filesystem
+ * @dentry: the directory to look up
* @ei: the eventfs_inode that represents the directory to create
- * @parent: parent dentry for this file.
*
- * This function will create a dentry for a directory represented by
+ * This function will look up a dentry for a directory represented by
* a eventfs_inode.
*/
-static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent)
+static struct dentry *lookup_dir_entry(struct dentry *dentry,
+ struct eventfs_inode *pei, struct eventfs_inode *ei)
{
struct tracefs_inode *ti;
- struct dentry *dentry;
struct inode *inode;
- dentry = eventfs_start_creating(ei->name, parent);
- if (IS_ERR(dentry))
- return dentry;
-
inode = tracefs_get_inode(dentry->d_sb);
if (unlikely(!inode))
- return eventfs_failed_creating(dentry);
+ return ERR_PTR(-ENOMEM);
/* If the user updated the directory's attributes, use them */
update_inode_attr(dentry, inode, &ei->attr,
@@ -371,11 +359,14 @@ static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent
/* Only directories have ti->private set to an ei, not files */
ti->private = ei;
+ dentry->d_fsdata = ei;
+ ei->dentry = dentry; // Remove me!
+
inc_nlink(inode);
- d_instantiate(dentry, inode);
+ d_add(dentry, inode);
inc_nlink(dentry->d_parent->d_inode);
fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
- return eventfs_end_creating(dentry);
+ return dentry;
}
static void free_ei(struct eventfs_inode *ei)
@@ -425,7 +416,7 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
}
/**
- * create_file_dentry - create a dentry for a file of an eventfs_inode
+ * lookup_file_dentry - create a dentry for a file of an eventfs_inode
* @ei: the eventfs_inode that the file will be created under
* @idx: the index into the d_children[] of the @ei
* @parent: The parent dentry of the created file.
@@ -438,157 +429,21 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
* address located at @e_dentry.
*/
static struct dentry *
-create_file_dentry(struct eventfs_inode *ei, int idx,
- struct dentry *parent, const char *name, umode_t mode, void *data,
+lookup_file_dentry(struct dentry *dentry,
+ struct eventfs_inode *ei, int idx,
+ umode_t mode, void *data,
const struct file_operations *fops)
{
struct eventfs_attr *attr = NULL;
struct dentry **e_dentry = &ei->d_children[idx];
- struct dentry *dentry;
-
- WARN_ON_ONCE(!inode_is_locked(parent->d_inode));
- mutex_lock(&eventfs_mutex);
- if (ei->is_freed) {
- mutex_unlock(&eventfs_mutex);
- return NULL;
- }
- /* If the e_dentry already has a dentry, use it */
- if (*e_dentry) {
- dget(*e_dentry);
- mutex_unlock(&eventfs_mutex);
- return *e_dentry;
- }
-
- /* ei->entry_attrs are protected by SRCU */
if (ei->entry_attrs)
attr = &ei->entry_attrs[idx];
- mutex_unlock(&eventfs_mutex);
-
- dentry = create_file(name, mode, attr, parent, data, fops);
+ dentry->d_fsdata = ei; // NOTE: ei of _parent_
+ lookup_file(dentry, mode, attr, data, fops);
- mutex_lock(&eventfs_mutex);
-
- if (IS_ERR_OR_NULL(dentry)) {
- /*
- * When the mutex was released, something else could have
- * created the dentry for this e_dentry. In which case
- * use that one.
- *
- * If ei->is_freed is set, the e_dentry is currently on its
- * way to being freed, don't return it. If e_dentry is NULL
- * it means it was already freed.
- */
- if (ei->is_freed) {
- dentry = NULL;
- } else {
- dentry = *e_dentry;
- dget(dentry);
- }
- mutex_unlock(&eventfs_mutex);
- return dentry;
- }
-
- if (!*e_dentry && !ei->is_freed) {
- *e_dentry = dentry;
- dentry->d_fsdata = ei;
- } else {
- /*
- * Should never happen unless we get here due to being freed.
- * Otherwise it means two dentries exist with the same name.
- */
- WARN_ON_ONCE(!ei->is_freed);
- dentry = NULL;
- }
- mutex_unlock(&eventfs_mutex);
-
- return dentry;
-}
-
-/**
- * eventfs_post_create_dir - post create dir routine
- * @ei: eventfs_inode of recently created dir
- *
- * Map the meta-data of files within an eventfs dir to their parent dentry
- */
-static void eventfs_post_create_dir(struct eventfs_inode *ei)
-{
- struct eventfs_inode *ei_child;
-
- lockdep_assert_held(&eventfs_mutex);
-
- /* srcu lock already held */
- /* fill parent-child relation */
- list_for_each_entry_srcu(ei_child, &ei->children, list,
- srcu_read_lock_held(&eventfs_srcu)) {
- ei_child->d_parent = ei->dentry;
- }
-}
-
-/**
- * create_dir_dentry - Create a directory dentry for the eventfs_inode
- * @pei: The eventfs_inode parent of ei.
- * @ei: The eventfs_inode to create the directory for
- * @parent: The dentry of the parent of this directory
- *
- * This creates and attaches a directory dentry to the eventfs_inode @ei.
- */
-static struct dentry *
-create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
- struct dentry *parent)
-{
- struct dentry *dentry = NULL;
-
- WARN_ON_ONCE(!inode_is_locked(parent->d_inode));
-
- mutex_lock(&eventfs_mutex);
- if (pei->is_freed || ei->is_freed) {
- mutex_unlock(&eventfs_mutex);
- return NULL;
- }
- if (ei->dentry) {
- /* If the eventfs_inode already has a dentry, use it */
- dentry = ei->dentry;
- dget(dentry);
- mutex_unlock(&eventfs_mutex);
- return dentry;
- }
- mutex_unlock(&eventfs_mutex);
-
- dentry = create_dir(ei, parent);
-
- mutex_lock(&eventfs_mutex);
-
- if (IS_ERR_OR_NULL(dentry) && !ei->is_freed) {
- /*
- * When the mutex was released, something else could have
- * created the dentry for this e_dentry. In which case
- * use that one.
- *
- * If ei->is_freed is set, the e_dentry is currently on its
- * way to being freed.
- */
- dentry = ei->dentry;
- if (dentry)
- dget(dentry);
- mutex_unlock(&eventfs_mutex);
- return dentry;
- }
-
- if (!ei->dentry && !ei->is_freed) {
- ei->dentry = dentry;
- eventfs_post_create_dir(ei);
- dentry->d_fsdata = ei;
- } else {
- /*
- * Should never happen unless we get here due to being freed.
- * Otherwise it means two dentries exist with the same name.
- */
- WARN_ON_ONCE(!ei->is_freed);
- dentry = NULL;
- }
- mutex_unlock(&eventfs_mutex);
+ *e_dentry = dentry; // Remove me
return dentry;
}
@@ -607,79 +462,49 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
struct dentry *dentry,
unsigned int flags)
{
- const struct file_operations *fops;
- const struct eventfs_entry *entry;
struct eventfs_inode *ei_child;
struct tracefs_inode *ti;
struct eventfs_inode *ei;
- struct dentry *ei_dentry = NULL;
- struct dentry *ret = NULL;
- struct dentry *d;
const char *name = dentry->d_name.name;
- umode_t mode;
- void *data;
- int idx;
- int i;
- int r;
ti = get_tracefs(dir);
if (!(ti->flags & TRACEFS_EVENT_INODE))
- return NULL;
-
- /* Grab srcu to prevent the ei from going away */
- idx = srcu_read_lock(&eventfs_srcu);
+ return ERR_PTR(-EIO);
- /*
- * Grab the eventfs_mutex to consistent value from ti->private.
- * This s
- */
mutex_lock(&eventfs_mutex);
- ei = READ_ONCE(ti->private);
- if (ei && !ei->is_freed)
- ei_dentry = READ_ONCE(ei->dentry);
- mutex_unlock(&eventfs_mutex);
- if (!ei || !ei_dentry)
+ ei = ti->private;
+ if (!ei || ei->is_freed)
goto out;
- data = ei->data;
-
- list_for_each_entry_srcu(ei_child, &ei->children, list,
- srcu_read_lock_held(&eventfs_srcu)) {
+ list_for_each_entry(ei_child, &ei->children, list) {
if (strcmp(ei_child->name, name) != 0)
continue;
- ret = simple_lookup(dir, dentry, flags);
- if (IS_ERR(ret))
+ if (ei_child->is_freed)
goto out;
- d = create_dir_dentry(ei, ei_child, ei_dentry);
- dput(d);
+ lookup_dir_entry(dentry, ei, ei_child);
goto out;
}
- for (i = 0; i < ei->nr_entries; i++) {
- entry = &ei->entries[i];
- if (strcmp(name, entry->name) == 0) {
- void *cdata = data;
- mutex_lock(&eventfs_mutex);
- /* If ei->is_freed, then the event itself may be too */
- if (!ei->is_freed)
- r = entry->callback(name, &mode, &cdata, &fops);
- else
- r = -1;
- mutex_unlock(&eventfs_mutex);
- if (r <= 0)
- continue;
- ret = simple_lookup(dir, dentry, flags);
- if (IS_ERR(ret))
- goto out;
- d = create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops);
- dput(d);
- break;
- }
+ for (int i = 0; i < ei->nr_entries; i++) {
+ void *data;
+ umode_t mode;
+ const struct file_operations *fops;
+ const struct eventfs_entry *entry = &ei->entries[i];
+
+ if (strcmp(name, entry->name) != 0)
+ continue;
+
+ data = ei->data;
+ if (entry->callback(name, &mode, &data, &fops) <= 0)
+ goto out;
+
+ lookup_file_dentry(dentry, ei, i, mode, data, fops);
+ goto out;
}
out:
- srcu_read_unlock(&eventfs_srcu, idx);
- return ret;
+ mutex_unlock(&eventfs_mutex);
+ return NULL;
}
/*
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index ad4c137b7be9..a24dfa7fcf23 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -495,75 +495,6 @@ struct dentry *tracefs_end_creating(struct dentry *dentry)
return dentry;
}
-/**
- * eventfs_start_creating - start the process of creating a dentry
- * @name: Name of the file created for the dentry
- * @parent: The parent dentry where this dentry will be created
- *
- * This is a simple helper function for the dynamically created eventfs
- * files. When the directory of the eventfs files are accessed, their
- * dentries are created on the fly. This function is used to start that
- * process.
- */
-struct dentry *eventfs_start_creating(const char *name, struct dentry *parent)
-{
- struct dentry *dentry;
- int error;
-
- /* Must always have a parent. */
- if (WARN_ON_ONCE(!parent))
- return ERR_PTR(-EINVAL);
-
- error = simple_pin_fs(&trace_fs_type, &tracefs_mount,
- &tracefs_mount_count);
- if (error)
- return ERR_PTR(error);
-
- if (unlikely(IS_DEADDIR(parent->d_inode)))
- dentry = ERR_PTR(-ENOENT);
- else
- dentry = lookup_one_len(name, parent, strlen(name));
-
- if (!IS_ERR(dentry) && dentry->d_inode) {
- dput(dentry);
- dentry = ERR_PTR(-EEXIST);
- }
-
- if (IS_ERR(dentry))
- simple_release_fs(&tracefs_mount, &tracefs_mount_count);
-
- return dentry;
-}
-
-/**
- * eventfs_failed_creating - clean up a failed eventfs dentry creation
- * @dentry: The dentry to clean up
- *
- * If after calling eventfs_start_creating(), a failure is detected, the
- * resources created by eventfs_start_creating() needs to be cleaned up. In
- * that case, this function should be called to perform that clean up.
- */
-struct dentry *eventfs_failed_creating(struct dentry *dentry)
-{
- dput(dentry);
- simple_release_fs(&tracefs_mount, &tracefs_mount_count);
- return NULL;
-}
-
-/**
- * eventfs_end_creating - Finish the process of creating a eventfs dentry
- * @dentry: The dentry that has successfully been created.
- *
- * This function is currently just a place holder to match
- * eventfs_start_creating(). In case any synchronization needs to be added,
- * this function will be used to implement that without having to modify
- * the callers of eventfs_start_creating().
- */
-struct dentry *eventfs_end_creating(struct dentry *dentry)
-{
- return dentry;
-}
-
/* Find the inode that this will use for default */
static struct inode *instance_inode(struct dentry *parent, struct inode *inode)
{
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 7d84349ade87..09037e2c173d 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -80,9 +80,6 @@ struct dentry *tracefs_start_creating(const char *name, struct dentry *parent);
struct dentry *tracefs_end_creating(struct dentry *dentry);
struct dentry *tracefs_failed_creating(struct dentry *dentry);
struct inode *tracefs_get_inode(struct super_block *sb);
-struct dentry *eventfs_start_creating(const char *name, struct dentry *parent);
-struct dentry *eventfs_failed_creating(struct dentry *dentry);
-struct dentry *eventfs_end_creating(struct dentry *dentry);
void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry);
#endif /* _TRACEFS_INTERNAL_H */
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 51/57] eventfs: Remove unused d_parent pointer field
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (49 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 50/57] tracefs: dentry lookup crapectomy Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 52/57] eventfs: Clean up dentry ops and add revalidate function Steven Rostedt
` (6 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Christian Brauner, Al Viro, Ajay Kaher
From: Linus Torvalds <torvalds@linux-foundation.org>
It's never used
Link: https://lore.kernel.org/linux-trace-kernel/202401291043.e62e89dc-oliver.sang@intel.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240131185512.961772428@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: c1504e510238 ("eventfs: Implement eventfs dir creation functions")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 408600be78cdb8c650a97ecc7ff411cb216811b5)
---
fs/tracefs/event_inode.c | 4 +---
fs/tracefs/internal.h | 2 --
2 files changed, 1 insertion(+), 5 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 04c2ab90f93e..16ca8d9759b1 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -680,10 +680,8 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode
INIT_LIST_HEAD(&ei->list);
mutex_lock(&eventfs_mutex);
- if (!parent->is_freed) {
+ if (!parent->is_freed)
list_add_tail(&ei->list, &parent->children);
- ei->d_parent = parent->dentry;
- }
mutex_unlock(&eventfs_mutex);
/* Was the parent freed? */
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 09037e2c173d..932733a2696a 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -36,7 +36,6 @@ struct eventfs_attr {
* @name: the name of the directory to create
* @children: link list into the child eventfs_inode
* @dentry: the dentry of the directory
- * @d_parent: pointer to the parent's dentry
* @d_children: The array of dentries to represent the files when created
* @entry_attrs: Saved mode and ownership of the @d_children
* @attr: Saved mode and ownership of eventfs_inode itself
@@ -51,7 +50,6 @@ struct eventfs_inode {
const char *name;
struct list_head children;
struct dentry *dentry; /* Check is_freed to access */
- struct dentry *d_parent;
struct dentry **d_children;
struct eventfs_attr *entry_attrs;
struct eventfs_attr attr;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 52/57] eventfs: Clean up dentry ops and add revalidate function
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (50 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 51/57] eventfs: Remove unused d_parent pointer field Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 53/57] eventfs: Get rid of dentry pointers without refcounts Steven Rostedt
` (5 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Christian Brauner, Al Viro, Ajay Kaher
From: Linus Torvalds <torvalds@linux-foundation.org>
In order for the dentries to stay up-to-date with the eventfs changes,
just add a 'd_revalidate' function that checks the 'is_freed' bit.
Also, clean up the dentry release to actually use d_release() rather
than the slightly odd d_iput() function. We don't care about the inode,
all we want to do is to get rid of the refcount to the eventfs data
added by dentry->d_fsdata.
It would probably be cleaner to make eventfs its own filesystem, or at
least set its own dentry ops when looking up eventfs files. But as it
is, only eventfs dentries use d_fsdata, so we don't really need to split
these things up by use.
Another thing that might be worth doing is to make all eventfs lookups
mark their dentries as not worth caching. We could do that with
d_delete(), but the DCACHE_DONTCACHE flag would likely be even better.
As it is, the dentries are all freeable, but they only tend to get freed
at memory pressure rather than more proactively. But that's a separate
issue.
Link: https://lore.kernel.org/linux-trace-kernel/202401291043.e62e89dc-oliver.sang@intel.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240131185513.124644253@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: c1504e510238 ("eventfs: Implement eventfs dir creation functions")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 8dce06e98c70a7fcbb4bca7d90faf40522e65c58)
---
fs/tracefs/event_inode.c | 5 ++---
fs/tracefs/inode.c | 27 ++++++++++++++++++---------
fs/tracefs/internal.h | 3 ++-
3 files changed, 22 insertions(+), 13 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 16ca8d9759b1..b2285d5f3fed 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -378,13 +378,12 @@ static void free_ei(struct eventfs_inode *ei)
}
/**
- * eventfs_set_ei_status_free - remove the dentry reference from an eventfs_inode
- * @ti: the tracefs_inode of the dentry
+ * eventfs_d_release - dentry is going away
* @dentry: dentry which has the reference to remove.
*
* Remove the association between a dentry from an eventfs_inode.
*/
-void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
+void eventfs_d_release(struct dentry *dentry)
{
struct eventfs_inode *ei;
int i;
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index a24dfa7fcf23..99caf1c3d0c4 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -377,21 +377,30 @@ static const struct super_operations tracefs_super_operations = {
.show_options = tracefs_show_options,
};
-static void tracefs_dentry_iput(struct dentry *dentry, struct inode *inode)
+/*
+ * It would be cleaner if eventfs had its own dentry ops.
+ *
+ * Note that d_revalidate is called potentially under RCU,
+ * so it can't take the eventfs mutex etc. It's fine - if
+ * we open a file just as it's marked dead, things will
+ * still work just fine, and just see the old stale case.
+ */
+static void tracefs_d_release(struct dentry *dentry)
{
- struct tracefs_inode *ti;
+ if (dentry->d_fsdata)
+ eventfs_d_release(dentry);
+}
- if (!dentry || !inode)
- return;
+static int tracefs_d_revalidate(struct dentry *dentry, unsigned int flags)
+{
+ struct eventfs_inode *ei = dentry->d_fsdata;
- ti = get_tracefs(inode);
- if (ti && ti->flags & TRACEFS_EVENT_INODE)
- eventfs_set_ei_status_free(ti, dentry);
- iput(inode);
+ return !(ei && ei->is_freed);
}
static const struct dentry_operations tracefs_dentry_operations = {
- .d_iput = tracefs_dentry_iput,
+ .d_revalidate = tracefs_d_revalidate,
+ .d_release = tracefs_d_release,
};
static int trace_fill_super(struct super_block *sb, void *data, int silent)
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 932733a2696a..4b50a0668055 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -78,6 +78,7 @@ struct dentry *tracefs_start_creating(const char *name, struct dentry *parent);
struct dentry *tracefs_end_creating(struct dentry *dentry);
struct dentry *tracefs_failed_creating(struct dentry *dentry);
struct inode *tracefs_get_inode(struct super_block *sb);
-void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry);
+
+void eventfs_d_release(struct dentry *dentry);
#endif /* _TRACEFS_INTERNAL_H */
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 53/57] eventfs: Get rid of dentry pointers without refcounts
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (51 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 52/57] eventfs: Clean up dentry ops and add revalidate function Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 54/57] eventfs: Warn if an eventfs_inode is freed without is_freed being set Steven Rostedt
` (4 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Christian Brauner, Al Viro, Ajay Kaher
From: Linus Torvalds <torvalds@linux-foundation.org>
The eventfs inode had pointers to dentries (and child dentries) without
actually holding a refcount on said pointer. That is fundamentally
broken, and while eventfs tried to then maintain coherence with dentries
going away by hooking into the '.d_iput' callback, that doesn't actually
work since it's not ordered wrt lookups.
There were two reasonms why eventfs tried to keep a pointer to a dentry:
- the creation of a 'events' directory would actually have a stable
dentry pointer that it created with tracefs_start_creating().
And it needed that dentry when tearing it all down again in
eventfs_remove_events_dir().
This use is actually ok, because the special top-level events
directory dentries are actually stable, not just a temporary cache of
the eventfs data structures.
- the 'eventfs_inode' (aka ei) needs to stay around as long as there
are dentries that refer to it.
It then used these dentry pointers as a replacement for doing
reference counting: it would try to make sure that there was only
ever one dentry associated with an event_inode, and keep a child
dentry array around to see which dentries might still refer to the
parent ei.
This gets rid of the invalid dentry pointer use, and renames the one
valid case to a different name to make it clear that it's not just any
random dentry.
The magic child dentry array that is kind of a "reverse reference list"
is simply replaced by having child dentries take a ref to the ei. As
does the directory dentries. That makes the broken use case go away.
Link: https://lore.kernel.org/linux-trace-kernel/202401291043.e62e89dc-oliver.sang@intel.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240131185513.280463000@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fixes: c1504e510238 ("eventfs: Implement eventfs dir creation functions")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 43aa6f97c2d03a52c1ddb86768575fc84344bdbb)
---
fs/tracefs/event_inode.c | 248 ++++++++++++---------------------------
fs/tracefs/internal.h | 7 +-
2 files changed, 78 insertions(+), 177 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index b2285d5f3fed..515fdace1eea 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -62,6 +62,35 @@ enum {
#define EVENTFS_MODE_MASK (EVENTFS_SAVE_MODE - 1)
+/*
+ * eventfs_inode reference count management.
+ *
+ * NOTE! We count only references from dentries, in the
+ * form 'dentry->d_fsdata'. There are also references from
+ * directory inodes ('ti->private'), but the dentry reference
+ * count is always a superset of the inode reference count.
+ */
+static void release_ei(struct kref *ref)
+{
+ struct eventfs_inode *ei = container_of(ref, struct eventfs_inode, kref);
+ kfree(ei->entry_attrs);
+ kfree_const(ei->name);
+ kfree_rcu(ei, rcu);
+}
+
+static inline void put_ei(struct eventfs_inode *ei)
+{
+ if (ei)
+ kref_put(&ei->kref, release_ei);
+}
+
+static inline struct eventfs_inode *get_ei(struct eventfs_inode *ei)
+{
+ if (ei)
+ kref_get(&ei->kref);
+ return ei;
+}
+
static struct dentry *eventfs_root_lookup(struct inode *dir,
struct dentry *dentry,
unsigned int flags);
@@ -289,7 +318,8 @@ static void update_inode_attr(struct dentry *dentry, struct inode *inode,
* directory. The inode.i_private pointer will point to @data in the open()
* call.
*/
-static struct dentry *lookup_file(struct dentry *dentry,
+static struct dentry *lookup_file(struct eventfs_inode *parent_ei,
+ struct dentry *dentry,
umode_t mode,
struct eventfs_attr *attr,
void *data,
@@ -302,7 +332,7 @@ static struct dentry *lookup_file(struct dentry *dentry,
mode |= S_IFREG;
if (WARN_ON_ONCE(!S_ISREG(mode)))
- return NULL;
+ return ERR_PTR(-EIO);
inode = tracefs_get_inode(dentry->d_sb);
if (unlikely(!inode))
@@ -321,9 +351,12 @@ static struct dentry *lookup_file(struct dentry *dentry,
ti = get_tracefs(inode);
ti->flags |= TRACEFS_EVENT_INODE;
+ // Files have their parent's ei as their fsdata
+ dentry->d_fsdata = get_ei(parent_ei);
+
d_add(dentry, inode);
fsnotify_create(dentry->d_parent->d_inode, dentry);
- return dentry;
+ return NULL;
};
/**
@@ -359,22 +392,29 @@ static struct dentry *lookup_dir_entry(struct dentry *dentry,
/* Only directories have ti->private set to an ei, not files */
ti->private = ei;
- dentry->d_fsdata = ei;
- ei->dentry = dentry; // Remove me!
+ dentry->d_fsdata = get_ei(ei);
inc_nlink(inode);
d_add(dentry, inode);
inc_nlink(dentry->d_parent->d_inode);
fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
- return dentry;
+ return NULL;
}
-static void free_ei(struct eventfs_inode *ei)
+static inline struct eventfs_inode *alloc_ei(const char *name)
{
- kfree_const(ei->name);
- kfree(ei->d_children);
- kfree(ei->entry_attrs);
- kfree(ei);
+ struct eventfs_inode *ei = kzalloc(sizeof(*ei), GFP_KERNEL);
+
+ if (!ei)
+ return NULL;
+
+ ei->name = kstrdup_const(name, GFP_KERNEL);
+ if (!ei->name) {
+ kfree(ei);
+ return NULL;
+ }
+ kref_init(&ei->kref);
+ return ei;
}
/**
@@ -385,39 +425,13 @@ static void free_ei(struct eventfs_inode *ei)
*/
void eventfs_d_release(struct dentry *dentry)
{
- struct eventfs_inode *ei;
- int i;
-
- mutex_lock(&eventfs_mutex);
-
- ei = dentry->d_fsdata;
- if (!ei)
- goto out;
-
- /* This could belong to one of the files of the ei */
- if (ei->dentry != dentry) {
- for (i = 0; i < ei->nr_entries; i++) {
- if (ei->d_children[i] == dentry)
- break;
- }
- if (WARN_ON_ONCE(i == ei->nr_entries))
- goto out;
- ei->d_children[i] = NULL;
- } else if (ei->is_freed) {
- free_ei(ei);
- } else {
- ei->dentry = NULL;
- }
-
- dentry->d_fsdata = NULL;
- out:
- mutex_unlock(&eventfs_mutex);
+ put_ei(dentry->d_fsdata);
}
/**
* lookup_file_dentry - create a dentry for a file of an eventfs_inode
* @ei: the eventfs_inode that the file will be created under
- * @idx: the index into the d_children[] of the @ei
+ * @idx: the index into the entry_attrs[] of the @ei
* @parent: The parent dentry of the created file.
* @name: The name of the file to create
* @mode: The mode of the file.
@@ -434,17 +448,11 @@ lookup_file_dentry(struct dentry *dentry,
const struct file_operations *fops)
{
struct eventfs_attr *attr = NULL;
- struct dentry **e_dentry = &ei->d_children[idx];
if (ei->entry_attrs)
attr = &ei->entry_attrs[idx];
- dentry->d_fsdata = ei; // NOTE: ei of _parent_
- lookup_file(dentry, mode, attr, data, fops);
-
- *e_dentry = dentry; // Remove me
-
- return dentry;
+ return lookup_file(ei, dentry, mode, attr, data, fops);
}
/**
@@ -465,6 +473,7 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
struct tracefs_inode *ti;
struct eventfs_inode *ei;
const char *name = dentry->d_name.name;
+ struct dentry *result = NULL;
ti = get_tracefs(dir);
if (!(ti->flags & TRACEFS_EVENT_INODE))
@@ -481,7 +490,7 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
continue;
if (ei_child->is_freed)
goto out;
- lookup_dir_entry(dentry, ei, ei_child);
+ result = lookup_dir_entry(dentry, ei, ei_child);
goto out;
}
@@ -498,12 +507,12 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
if (entry->callback(name, &mode, &data, &fops) <= 0)
goto out;
- lookup_file_dentry(dentry, ei, i, mode, data, fops);
+ result = lookup_file_dentry(dentry, ei, i, mode, data, fops);
goto out;
}
out:
mutex_unlock(&eventfs_mutex);
- return NULL;
+ return result;
}
/*
@@ -653,25 +662,10 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode
if (!parent)
return ERR_PTR(-EINVAL);
- ei = kzalloc(sizeof(*ei), GFP_KERNEL);
+ ei = alloc_ei(name);
if (!ei)
return ERR_PTR(-ENOMEM);
- ei->name = kstrdup_const(name, GFP_KERNEL);
- if (!ei->name) {
- kfree(ei);
- return ERR_PTR(-ENOMEM);
- }
-
- if (size) {
- ei->d_children = kcalloc(size, sizeof(*ei->d_children), GFP_KERNEL);
- if (!ei->d_children) {
- kfree_const(ei->name);
- kfree(ei);
- return ERR_PTR(-ENOMEM);
- }
- }
-
ei->entries = entries;
ei->nr_entries = size;
ei->data = data;
@@ -685,7 +679,7 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode
/* Was the parent freed? */
if (list_empty(&ei->list)) {
- free_ei(ei);
+ put_ei(ei);
ei = NULL;
}
return ei;
@@ -720,28 +714,20 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
if (IS_ERR(dentry))
return ERR_CAST(dentry);
- ei = kzalloc(sizeof(*ei), GFP_KERNEL);
+ ei = alloc_ei(name);
if (!ei)
- goto fail_ei;
+ goto fail;
inode = tracefs_get_inode(dentry->d_sb);
if (unlikely(!inode))
goto fail;
- if (size) {
- ei->d_children = kcalloc(size, sizeof(*ei->d_children), GFP_KERNEL);
- if (!ei->d_children)
- goto fail;
- }
-
- ei->dentry = dentry;
+ // Note: we have a ref to the dentry from tracefs_start_creating()
+ ei->events_dir = dentry;
ei->entries = entries;
ei->nr_entries = size;
ei->is_events = 1;
ei->data = data;
- ei->name = kstrdup_const(name, GFP_KERNEL);
- if (!ei->name)
- goto fail;
/* Save the ownership of this directory */
uid = d_inode(dentry->d_parent)->i_uid;
@@ -772,7 +758,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
inode->i_op = &eventfs_root_dir_inode_operations;
inode->i_fop = &eventfs_file_operations;
- dentry->d_fsdata = ei;
+ dentry->d_fsdata = get_ei(ei);
/* directory inodes start off with i_nlink == 2 (for "." entry) */
inc_nlink(inode);
@@ -784,72 +770,11 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
return ei;
fail:
- kfree(ei->d_children);
- kfree(ei);
- fail_ei:
+ put_ei(ei);
tracefs_failed_creating(dentry);
return ERR_PTR(-ENOMEM);
}
-static LLIST_HEAD(free_list);
-
-static void eventfs_workfn(struct work_struct *work)
-{
- struct eventfs_inode *ei, *tmp;
- struct llist_node *llnode;
-
- llnode = llist_del_all(&free_list);
- llist_for_each_entry_safe(ei, tmp, llnode, llist) {
- /* This dput() matches the dget() from unhook_dentry() */
- for (int i = 0; i < ei->nr_entries; i++) {
- if (ei->d_children[i])
- dput(ei->d_children[i]);
- }
- /* This should only get here if it had a dentry */
- if (!WARN_ON_ONCE(!ei->dentry))
- dput(ei->dentry);
- }
-}
-
-static DECLARE_WORK(eventfs_work, eventfs_workfn);
-
-static void free_rcu_ei(struct rcu_head *head)
-{
- struct eventfs_inode *ei = container_of(head, struct eventfs_inode, rcu);
-
- if (ei->dentry) {
- /* Do not free the ei until all references of dentry are gone */
- if (llist_add(&ei->llist, &free_list))
- queue_work(system_unbound_wq, &eventfs_work);
- return;
- }
-
- /* If the ei doesn't have a dentry, neither should its children */
- for (int i = 0; i < ei->nr_entries; i++) {
- WARN_ON_ONCE(ei->d_children[i]);
- }
-
- free_ei(ei);
-}
-
-static void unhook_dentry(struct dentry *dentry)
-{
- if (!dentry)
- return;
- /*
- * Need to add a reference to the dentry that is expected by
- * simple_recursive_removal(), which will include a dput().
- */
- dget(dentry);
-
- /*
- * Also add a reference for the dput() in eventfs_workfn().
- * That is required as that dput() will free the ei after
- * the SRCU grace period is over.
- */
- dget(dentry);
-}
-
/**
* eventfs_remove_rec - remove eventfs dir or file from list
* @ei: eventfs_inode to be removed.
@@ -862,8 +787,6 @@ static void eventfs_remove_rec(struct eventfs_inode *ei, int level)
{
struct eventfs_inode *ei_child;
- if (!ei)
- return;
/*
* Check recursion depth. It should never be greater than 3:
* 0 - events/
@@ -875,28 +798,12 @@ static void eventfs_remove_rec(struct eventfs_inode *ei, int level)
return;
/* search for nested folders or files */
- list_for_each_entry_srcu(ei_child, &ei->children, list,
- lockdep_is_held(&eventfs_mutex)) {
- /* Children only have dentry if parent does */
- WARN_ON_ONCE(ei_child->dentry && !ei->dentry);
+ list_for_each_entry(ei_child, &ei->children, list)
eventfs_remove_rec(ei_child, level + 1);
- }
-
ei->is_freed = 1;
-
- for (int i = 0; i < ei->nr_entries; i++) {
- if (ei->d_children[i]) {
- /* Children only have dentry if parent does */
- WARN_ON_ONCE(!ei->dentry);
- unhook_dentry(ei->d_children[i]);
- }
- }
-
- unhook_dentry(ei->dentry);
-
- list_del_rcu(&ei->list);
- call_srcu(&eventfs_srcu, &ei->rcu, free_rcu_ei);
+ list_del(&ei->list);
+ put_ei(ei);
}
/**
@@ -907,22 +814,12 @@ static void eventfs_remove_rec(struct eventfs_inode *ei, int level)
*/
void eventfs_remove_dir(struct eventfs_inode *ei)
{
- struct dentry *dentry;
-
if (!ei)
return;
mutex_lock(&eventfs_mutex);
- dentry = ei->dentry;
eventfs_remove_rec(ei, 0);
mutex_unlock(&eventfs_mutex);
-
- /*
- * If any of the ei children has a dentry, then the ei itself
- * must have a dentry.
- */
- if (dentry)
- simple_recursive_removal(dentry, NULL);
}
/**
@@ -935,7 +832,11 @@ void eventfs_remove_events_dir(struct eventfs_inode *ei)
{
struct dentry *dentry;
- dentry = ei->dentry;
+ dentry = ei->events_dir;
+ if (!dentry)
+ return;
+
+ ei->events_dir = NULL;
eventfs_remove_dir(ei);
/*
@@ -945,5 +846,6 @@ void eventfs_remove_events_dir(struct eventfs_inode *ei)
* sticks around while the other ei->dentry are created
* and destroyed dynamically.
*/
+ d_invalidate(dentry);
dput(dentry);
}
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 4b50a0668055..1886f1826cd8 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -35,8 +35,7 @@ struct eventfs_attr {
* @entries: the array of entries representing the files in the directory
* @name: the name of the directory to create
* @children: link list into the child eventfs_inode
- * @dentry: the dentry of the directory
- * @d_children: The array of dentries to represent the files when created
+ * @events_dir: the dentry of the events directory
* @entry_attrs: Saved mode and ownership of the @d_children
* @attr: Saved mode and ownership of eventfs_inode itself
* @data: The private data to pass to the callbacks
@@ -45,12 +44,12 @@ struct eventfs_attr {
* @nr_entries: The number of items in @entries
*/
struct eventfs_inode {
+ struct kref kref;
struct list_head list;
const struct eventfs_entry *entries;
const char *name;
struct list_head children;
- struct dentry *dentry; /* Check is_freed to access */
- struct dentry **d_children;
+ struct dentry *events_dir;
struct eventfs_attr *entry_attrs;
struct eventfs_attr attr;
void *data;
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 54/57] eventfs: Warn if an eventfs_inode is freed without is_freed being set
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (52 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 53/57] eventfs: Get rid of dentry pointers without refcounts Steven Rostedt
@ 2024-02-06 12:09 ` Steven Rostedt
2024-02-06 12:10 ` [v6.6][PATCH 55/57] eventfs: Restructure eventfs_inode structure to be more condensed Steven Rostedt
` (3 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:09 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Christian Brauner, Al Viro, Ajay Kaher
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
There should never be a case where an evenfs_inode is being freed without
is_freed being set. Add a WARN_ON_ONCE() if it ever happens. That would
mean there was one too many put_ei()s.
Link: https://lore.kernel.org/linux-trace-kernel/20240201161616.843551963@goodmis.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 5a49f996046ba947466bc7461e4b19c4d1daf978)
---
fs/tracefs/event_inode.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 515fdace1eea..ca7daee7c811 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -73,6 +73,9 @@ enum {
static void release_ei(struct kref *ref)
{
struct eventfs_inode *ei = container_of(ref, struct eventfs_inode, kref);
+
+ WARN_ON_ONCE(!ei->is_freed);
+
kfree(ei->entry_attrs);
kfree_const(ei->name);
kfree_rcu(ei, rcu);
@@ -84,6 +87,14 @@ static inline void put_ei(struct eventfs_inode *ei)
kref_put(&ei->kref, release_ei);
}
+static inline void free_ei(struct eventfs_inode *ei)
+{
+ if (ei) {
+ ei->is_freed = 1;
+ put_ei(ei);
+ }
+}
+
static inline struct eventfs_inode *get_ei(struct eventfs_inode *ei)
{
if (ei)
@@ -679,7 +690,7 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode
/* Was the parent freed? */
if (list_empty(&ei->list)) {
- put_ei(ei);
+ free_ei(ei);
ei = NULL;
}
return ei;
@@ -770,7 +781,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
return ei;
fail:
- put_ei(ei);
+ free_ei(ei);
tracefs_failed_creating(dentry);
return ERR_PTR(-ENOMEM);
}
@@ -801,9 +812,8 @@ static void eventfs_remove_rec(struct eventfs_inode *ei, int level)
list_for_each_entry(ei_child, &ei->children, list)
eventfs_remove_rec(ei_child, level + 1);
- ei->is_freed = 1;
list_del(&ei->list);
- put_ei(ei);
+ free_ei(ei);
}
/**
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 55/57] eventfs: Restructure eventfs_inode structure to be more condensed
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (53 preceding siblings ...)
2024-02-06 12:09 ` [v6.6][PATCH 54/57] eventfs: Warn if an eventfs_inode is freed without is_freed being set Steven Rostedt
@ 2024-02-06 12:10 ` Steven Rostedt
2024-02-06 12:10 ` [v6.6][PATCH 56/57] eventfs: Remove fsnotify*() functions from lookup() Steven Rostedt
` (2 subsequent siblings)
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:10 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Christian Brauner, Al Viro, Ajay Kaher
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Some of the eventfs_inode structure has holes in it. Rework the structure
to be a bit more condensed, and also remove the no longer used llist
field.
Link: https://lore.kernel.org/linux-trace-kernel/20240201161617.002321438@goodmis.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 264424dfdd5cbd92bc5b5ddf93944929fc877fac)
---
fs/tracefs/internal.h | 27 ++++++++++++---------------
1 file changed, 12 insertions(+), 15 deletions(-)
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 1886f1826cd8..beb3dcd0e434 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -32,40 +32,37 @@ struct eventfs_attr {
/*
* struct eventfs_inode - hold the properties of the eventfs directories.
* @list: link list into the parent directory
+ * @rcu: Union with @list for freeing
+ * @children: link list into the child eventfs_inode
* @entries: the array of entries representing the files in the directory
* @name: the name of the directory to create
- * @children: link list into the child eventfs_inode
* @events_dir: the dentry of the events directory
* @entry_attrs: Saved mode and ownership of the @d_children
- * @attr: Saved mode and ownership of eventfs_inode itself
* @data: The private data to pass to the callbacks
+ * @attr: Saved mode and ownership of eventfs_inode itself
* @is_freed: Flag set if the eventfs is on its way to be freed
* Note if is_freed is set, then dentry is corrupted.
+ * @is_events: Flag set for only the top level "events" directory
* @nr_entries: The number of items in @entries
+ * @ino: The saved inode number
*/
struct eventfs_inode {
- struct kref kref;
- struct list_head list;
+ union {
+ struct list_head list;
+ struct rcu_head rcu;
+ };
+ struct list_head children;
const struct eventfs_entry *entries;
const char *name;
- struct list_head children;
struct dentry *events_dir;
struct eventfs_attr *entry_attrs;
- struct eventfs_attr attr;
void *data;
+ struct eventfs_attr attr;
+ struct kref kref;
unsigned int is_freed:1;
unsigned int is_events:1;
unsigned int nr_entries:30;
unsigned int ino;
- /*
- * Union - used for deletion
- * @llist: for calling dput() if needed after RCU
- * @rcu: eventfs_inode to delete in RCU
- */
- union {
- struct llist_node llist;
- struct rcu_head rcu;
- };
};
static inline struct tracefs_inode *get_tracefs(const struct inode *inode)
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 56/57] eventfs: Remove fsnotify*() functions from lookup()
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (54 preceding siblings ...)
2024-02-06 12:10 ` [v6.6][PATCH 55/57] eventfs: Restructure eventfs_inode structure to be more condensed Steven Rostedt
@ 2024-02-06 12:10 ` Steven Rostedt
2024-02-06 12:10 ` [v6.6][PATCH 57/57] eventfs: Keep all directory links at 1 Steven Rostedt
2024-02-20 15:11 ` [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Greg Kroah-Hartman
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:10 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Christian Brauner, Al Viro, Ajay Kaher, Al Viro
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The dentries and inodes are created when referenced in the lookup code.
There's no reason to call fsnotify_*() functions when they are created by
a reference. It doesn't make any sense.
Link: https://lore.kernel.org/linux-trace-kernel/20240201002719.GS2087318@ZenIV/
Link: https://lore.kernel.org/linux-trace-kernel/20240201161617.166973329@goodmis.org
Cc: stable@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Fixes: a376007917776 ("eventfs: Implement functions to create files and dirs when accessed");
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit 12d823b31fadf47c8f36ecada7abac5f903cac33)
---
fs/tracefs/event_inode.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index ca7daee7c811..9e031e5a2713 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -366,7 +366,6 @@ static struct dentry *lookup_file(struct eventfs_inode *parent_ei,
dentry->d_fsdata = get_ei(parent_ei);
d_add(dentry, inode);
- fsnotify_create(dentry->d_parent->d_inode, dentry);
return NULL;
};
@@ -408,7 +407,6 @@ static struct dentry *lookup_dir_entry(struct dentry *dentry,
inc_nlink(inode);
d_add(dentry, inode);
inc_nlink(dentry->d_parent->d_inode);
- fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
return NULL;
}
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* [v6.6][PATCH 57/57] eventfs: Keep all directory links at 1
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (55 preceding siblings ...)
2024-02-06 12:10 ` [v6.6][PATCH 56/57] eventfs: Remove fsnotify*() functions from lookup() Steven Rostedt
@ 2024-02-06 12:10 ` Steven Rostedt
2024-02-20 15:11 ` [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Greg Kroah-Hartman
57 siblings, 0 replies; 59+ messages in thread
From: Steven Rostedt @ 2024-02-06 12:10 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Linus Torvalds, Greg Kroah-Hartman, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers,
Christian Brauner, Al Viro, Ajay Kaher, Al Viro
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
The directory link count in eventfs was somewhat bogus. It was only being
updated when a directory child was being looked up and not on creation.
One solution would be to update in get_attr() the link count by iterating
the ei->children list and then adding 2. But that could slow down simple
stat() calls, especially if it's done on all directories in eventfs.
Another solution would be to add a parent pointer to the eventfs_inode
and keep track of the number of sub directories it has on creation. But
this adds overhead for something not really worthwhile.
The solution decided upon is to keep all directory links in eventfs as 1.
This tells user space not to rely on the hard links of directories. Which
in this case it shouldn't.
Link: https://lore.kernel.org/linux-trace-kernel/20240201002719.GS2087318@ZenIV/
Link: https://lore.kernel.org/linux-trace-kernel/20240201161617.339968298@goodmis.org
Cc: stable@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Ajay Kaher <ajay.kaher@broadcom.com>
Fixes: c1504e510238 ("eventfs: Implement eventfs dir creation functions")
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
(cherry picked from commit ca185770db914869ff9fe773bac5e0e5e4165b83)
---
fs/tracefs/event_inode.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 9e031e5a2713..110e8a272189 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -404,9 +404,7 @@ static struct dentry *lookup_dir_entry(struct dentry *dentry,
dentry->d_fsdata = get_ei(ei);
- inc_nlink(inode);
d_add(dentry, inode);
- inc_nlink(dentry->d_parent->d_inode);
return NULL;
}
@@ -769,9 +767,17 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
dentry->d_fsdata = get_ei(ei);
- /* directory inodes start off with i_nlink == 2 (for "." entry) */
- inc_nlink(inode);
+ /*
+ * Keep all eventfs directories with i_nlink == 1.
+ * Due to the dynamic nature of the dentry creations and not
+ * wanting to add a pointer to the parent eventfs_inode in the
+ * eventfs_inode structure, keeping the i_nlink in sync with the
+ * number of directories would cause too much complexity for
+ * something not worth much. Keeping directory links at 1
+ * tells userspace not to trust the link number.
+ */
d_instantiate(dentry, inode);
+ /* The dentry of the "events" parent does keep track though */
inc_nlink(dentry->d_parent->d_inode);
fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
tracefs_end_creating(dentry);
--
2.43.0
^ permalink raw reply related [flat|nested] 59+ messages in thread
* Re: [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
` (56 preceding siblings ...)
2024-02-06 12:10 ` [v6.6][PATCH 57/57] eventfs: Keep all directory links at 1 Steven Rostedt
@ 2024-02-20 15:11 ` Greg Kroah-Hartman
57 siblings, 0 replies; 59+ messages in thread
From: Greg Kroah-Hartman @ 2024-02-20 15:11 UTC (permalink / raw)
To: Steven Rostedt
Cc: linux-kernel, stable, Linus Torvalds, Sasha Levin,
Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers
On Tue, Feb 06, 2024 at 07:09:05AM -0500, Steven Rostedt wrote:
>
> This is a backport of all the work that lead up to the work that Linus made
> on eventfs. I trust Linus's version more so than the versions in 6.6 and
> 6.7. There may be plenty of hidden issues due to the design.
>
> This is the update for 6.6. It includes Linus's updates as well as all the
> patches leading up to them. As the eventfs work went in in two parts, half
> went in in 6.6 and the other in 6.7, there were 6 backports that were done
> custom to 6.6 as the bugs found in 6.7 were in 6.6 but implemented
> differently. This series starts with reverting those 6 backports and then
> applying the updated patches to get to Linus's simplification.
>
> I ran these through my full test suite that I use before sending anything to
> Linus, although I did not run my "bisect" test that walks through the
> patches. The tests were just run on the end result.
>
> This was created with the following command against v6.6.15, after reverting
> the 6 patches:
All now queued up, thanks!
greg k-h
^ permalink raw reply [flat|nested] 59+ messages in thread
end of thread, other threads:[~2024-02-20 15:11 UTC | newest]
Thread overview: 59+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-02-06 12:09 [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 01/57] Revert "eventfs: Do not allow NULL parent to eventfs_start_creating()" Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 02/57] Revert "eventfs: Check for NULL ef in eventfs_set_attr()" Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 03/57] Revert "eventfs: Use simple_recursive_removal() to clean up dentries" Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 04/57] Revert "eventfs: Delete eventfs_inode when the last dentry is freed" Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 05/57] Revert "eventfs: Save ownership and mode" Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 06/57] Revert "eventfs: Remove "is_freed" union with rcu head" Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 07/57] eventfs: Remove eventfs_file and just use eventfs_inode Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 08/57] eventfs: Use eventfs_remove_events_dir() Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 09/57] eventfs: Use ERR_CAST() in eventfs_create_events_dir() Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 10/57] eventfs: Fix failure path " Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 11/57] tracefs/eventfs: Modify mismatched function name Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 12/57] eventfs: Fix WARN_ON() in create_file_dentry() Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 13/57] eventfs: Fix typo in eventfs_inode union comment Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 14/57] eventfs: Remove extra dget() in eventfs_create_events_dir() Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 15/57] eventfs: Fix kerneldoc of eventfs_remove_rec() Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 16/57] eventfs: Remove "is_freed" union with rcu head Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 17/57] eventfs: Have a free_ei() that just frees the eventfs_inode Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 18/57] eventfs: Test for ei->is_freed when accessing ei->dentry Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 19/57] eventfs: Save ownership and mode Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 20/57] eventfs: Hold eventfs_mutex when calling callback functions Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 21/57] eventfs: Delete eventfs_inode when the last dentry is freed Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 22/57] eventfs: Remove special processing of dput() of events directory Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 23/57] eventfs: Use simple_recursive_removal() to clean up dentries Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 24/57] eventfs: Remove expectation that ei->is_freed means ei->dentry == NULL Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 25/57] eventfs: Do not invalidate dentry in create_file/dir_dentry() Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 26/57] eventfs: Use GFP_NOFS for allocation when eventfs_mutex is held Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 27/57] eventfs: Move taking of inode_lock into dcache_dir_open_wrapper() Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 28/57] eventfs: Do not allow NULL parent to eventfs_start_creating() Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 29/57] eventfs: Make sure that parent->d_inode is locked in creating files/dirs Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 30/57] eventfs: Fix events beyond NAME_MAX blocking tasks Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 31/57] eventfs: Have event files and directories default to parent uid and gid Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 32/57] eventfs: Fix file and directory uid and gid ownership Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 33/57] tracefs: Check for dentry->d_inode exists in set_gid() Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 34/57] eventfs: Fix bitwise fields for "is_events" Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 35/57] eventfs: Remove "lookup" parameter from create_dir/file_dentry() Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 36/57] eventfs: Stop using dcache_readdir() for getdents() Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 37/57] tracefs/eventfs: Use root and instance inodes as default ownership Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 38/57] eventfs: Have eventfs_iterate() stop immediately if ei->is_freed is set Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 39/57] eventfs: Do ctx->pos update for all iterations in eventfs_iterate() Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 40/57] eventfs: Read ei->entries before ei->children " Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 41/57] eventfs: Shortcut eventfs_iterate() by skipping entries already read Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 42/57] eventfs: Have the inodes all for files and directories all be the same Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 43/57] eventfs: Do not create dentries nor inodes in iterate_shared Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 44/57] eventfs: Use kcalloc() instead of kzalloc() Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 45/57] eventfs: Save directory inodes in the eventfs_inode structure Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 46/57] tracefs: remove stale update_gid code Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 47/57] tracefs: Zero out the tracefs_inode when allocating it Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 48/57] eventfs: Initialize the tracefs inode properly Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 49/57] tracefs: Avoid using the ei->dentry pointer unnecessarily Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 50/57] tracefs: dentry lookup crapectomy Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 51/57] eventfs: Remove unused d_parent pointer field Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 52/57] eventfs: Clean up dentry ops and add revalidate function Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 53/57] eventfs: Get rid of dentry pointers without refcounts Steven Rostedt
2024-02-06 12:09 ` [v6.6][PATCH 54/57] eventfs: Warn if an eventfs_inode is freed without is_freed being set Steven Rostedt
2024-02-06 12:10 ` [v6.6][PATCH 55/57] eventfs: Restructure eventfs_inode structure to be more condensed Steven Rostedt
2024-02-06 12:10 ` [v6.6][PATCH 56/57] eventfs: Remove fsnotify*() functions from lookup() Steven Rostedt
2024-02-06 12:10 ` [v6.6][PATCH 57/57] eventfs: Keep all directory links at 1 Steven Rostedt
2024-02-20 15:11 ` [v6.6][PATCH 00/57] eventfs: Linus's updates for 6.6 Greg Kroah-Hartman
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