* [PATCHES] namei cleanups
@ 2021-06-08 11:38 Al Viro
2021-06-08 11:39 ` [PATCH 1/4] switch file_open_root() to struct path Al Viro
2021-06-08 12:12 ` [PATCHES] namei cleanups Christian Brauner
0 siblings, 2 replies; 6+ messages in thread
From: Al Viro @ 2021-06-08 11:38 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
Small namei.c patch series, mostly to simplify the rules
for nameidata state. It's in #work.namei and it's actually from
the previous cycle - didn't post it for review in time...
Changes visible outside of fs/namei.c: file_open_root()
calling conventions change, some freed bits in LOOKUP_... space.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/4] switch file_open_root() to struct path
2021-06-08 11:38 [PATCHES] namei cleanups Al Viro
@ 2021-06-08 11:39 ` Al Viro
2021-06-08 11:39 ` [PATCH 2/4] take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space Al Viro
` (2 more replies)
2021-06-08 12:12 ` [PATCHES] namei cleanups Christian Brauner
1 sibling, 3 replies; 6+ messages in thread
From: Al Viro @ 2021-06-08 11:39 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
... and provide file_open_root_mnt(), using the root of given mount.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
Documentation/filesystems/porting.rst | 9 +++++++++
arch/um/drivers/mconsole_kern.c | 2 +-
fs/coredump.c | 4 ++--
fs/fhandle.c | 2 +-
fs/internal.h | 2 +-
fs/kernel_read_file.c | 2 +-
fs/namei.c | 8 +++-----
fs/open.c | 4 ++--
fs/proc/proc_sysctl.c | 2 +-
include/linux/fs.h | 8 +++++++-
kernel/usermode_driver.c | 2 +-
11 files changed, 29 insertions(+), 16 deletions(-)
diff --git a/Documentation/filesystems/porting.rst b/Documentation/filesystems/porting.rst
index 0302035781be..9bb2b35f90bb 100644
--- a/Documentation/filesystems/porting.rst
+++ b/Documentation/filesystems/porting.rst
@@ -890,3 +890,12 @@ been called or returned with non -EIOCBQUEUED code.
mnt_want_write_file() can now only be paired with mnt_drop_write_file(),
whereas previously it could be paired with mnt_drop_write() as well.
+
+---
+
+**mandatory**
+
+Calling conventions for file_open_root() changed; now it takes struct path *
+instead of passing mount and dentry separately. For callers that used to
+pass <mnt, mnt->mnt_root> pair (i.e. the root of given mount), a new helper
+is provided - file_open_root_mnt(). In-tree users adjusted.
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index 6d00af25ec6b..c42b10024e26 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -140,7 +140,7 @@ void mconsole_proc(struct mc_request *req)
mconsole_reply(req, "Proc not available", 1, 0);
goto out;
}
- file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY, 0);
+ file = file_open_root_mnt(mnt, ptr, O_RDONLY, 0);
if (IS_ERR(file)) {
mconsole_reply(req, "Failed to open file", 1, 0);
printk(KERN_ERR "open /proc/%s: %ld\n", ptr, PTR_ERR(file));
diff --git a/fs/coredump.c b/fs/coredump.c
index 1c0fdc1aa70b..087db444b06b 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -755,8 +755,8 @@ void do_coredump(const kernel_siginfo_t *siginfo)
task_lock(&init_task);
get_fs_root(init_task.fs, &root);
task_unlock(&init_task);
- cprm.file = file_open_root(root.dentry, root.mnt,
- cn.corename, open_flags, 0600);
+ cprm.file = file_open_root(&root, cn.corename,
+ open_flags, 0600);
path_put(&root);
} else {
cprm.file = filp_open(cn.corename, open_flags, 0600);
diff --git a/fs/fhandle.c b/fs/fhandle.c
index ec6feeccc276..6630c69c23a2 100644
--- a/fs/fhandle.c
+++ b/fs/fhandle.c
@@ -229,7 +229,7 @@ static long do_handle_open(int mountdirfd, struct file_handle __user *ufh,
path_put(&path);
return fd;
}
- file = file_open_root(path.dentry, path.mnt, "", open_flag, 0);
+ file = file_open_root(&path, "", open_flag, 0);
if (IS_ERR(file)) {
put_unused_fd(fd);
retval = PTR_ERR(file);
diff --git a/fs/internal.h b/fs/internal.h
index 6aeae7ef3380..3ce8edbaa3ca 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -129,7 +129,7 @@ struct open_flags {
};
extern struct file *do_filp_open(int dfd, struct filename *pathname,
const struct open_flags *op);
-extern struct file *do_file_open_root(struct dentry *, struct vfsmount *,
+extern struct file *do_file_open_root(const struct path *,
const char *, const struct open_flags *);
extern struct open_how build_open_how(int flags, umode_t mode);
extern int build_open_flags(const struct open_how *how, struct open_flags *op);
diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c
index 90d255fbdd9b..87aac4c72c37 100644
--- a/fs/kernel_read_file.c
+++ b/fs/kernel_read_file.c
@@ -160,7 +160,7 @@ int kernel_read_file_from_path_initns(const char *path, loff_t offset,
get_fs_root(init_task.fs, &root);
task_unlock(&init_task);
- file = file_open_root(root.dentry, root.mnt, path, O_RDONLY, 0);
+ file = file_open_root(&root, path, O_RDONLY, 0);
path_put(&root);
if (IS_ERR(file))
return PTR_ERR(file);
diff --git a/fs/namei.c b/fs/namei.c
index 48a2f288e802..4b6cf4974dd7 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3533,7 +3533,7 @@ struct file *do_filp_open(int dfd, struct filename *pathname,
return filp;
}
-struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
+struct file *do_file_open_root(const struct path *root,
const char *name, const struct open_flags *op)
{
struct nameidata nd;
@@ -3541,16 +3541,14 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
struct filename *filename;
int flags = op->lookup_flags | LOOKUP_ROOT;
- nd.root.mnt = mnt;
- nd.root.dentry = dentry;
-
- if (d_is_symlink(dentry) && op->intent & LOOKUP_OPEN)
+ if (d_is_symlink(root->dentry) && op->intent & LOOKUP_OPEN)
return ERR_PTR(-ELOOP);
filename = getname_kernel(name);
if (IS_ERR(filename))
return ERR_CAST(filename);
+ nd.root = *root;
set_nameidata(&nd, -1, filename);
file = path_openat(&nd, op, flags | LOOKUP_RCU);
if (unlikely(file == ERR_PTR(-ECHILD)))
diff --git a/fs/open.c b/fs/open.c
index e53af13b5835..b3c904e82e2a 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -1156,7 +1156,7 @@ struct file *filp_open(const char *filename, int flags, umode_t mode)
}
EXPORT_SYMBOL(filp_open);
-struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
+struct file *file_open_root(const struct path *root,
const char *filename, int flags, umode_t mode)
{
struct open_flags op;
@@ -1164,7 +1164,7 @@ struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
int err = build_open_flags(&how, &op);
if (err)
return ERR_PTR(err);
- return do_file_open_root(dentry, mnt, filename, &op);
+ return do_file_open_root(root, filename, &op);
}
EXPORT_SYMBOL(file_open_root);
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 984e42f8cb11..6606f21fc195 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -1806,7 +1806,7 @@ static int process_sysctl_arg(char *param, char *val,
panic("%s: Failed to allocate path for %s\n", __func__, param);
strreplace(path, '.', '/');
- file = file_open_root((*proc_mnt)->mnt_root, *proc_mnt, path, O_WRONLY, 0);
+ file = file_open_root_mnt(*proc_mnt, path, O_WRONLY, 0);
if (IS_ERR(file)) {
err = PTR_ERR(file);
if (err == -ENOENT)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index ec8f3ddf4a6a..1acea2bb9d60 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2632,8 +2632,14 @@ extern long do_sys_open(int dfd, const char __user *filename, int flags,
umode_t mode);
extern struct file *file_open_name(struct filename *, int, umode_t);
extern struct file *filp_open(const char *, int, umode_t);
-extern struct file *file_open_root(struct dentry *, struct vfsmount *,
+extern struct file *file_open_root(const struct path *,
const char *, int, umode_t);
+static inline struct file *file_open_root_mnt(struct vfsmount *mnt,
+ const char *name, int flags, umode_t mode)
+{
+ return file_open_root(&(struct path){.mnt = mnt, .dentry = mnt->mnt_root},
+ name, flags, mode);
+}
extern struct file * dentry_open(const struct path *, int, const struct cred *);
extern struct file * open_with_fake_path(const struct path *, int,
struct inode*, const struct cred *);
diff --git a/kernel/usermode_driver.c b/kernel/usermode_driver.c
index 0b35212ffc3d..78353cb73836 100644
--- a/kernel/usermode_driver.c
+++ b/kernel/usermode_driver.c
@@ -26,7 +26,7 @@ static struct vfsmount *blob_to_mnt(const void *data, size_t len, const char *na
if (IS_ERR(mnt))
return mnt;
- file = file_open_root(mnt->mnt_root, mnt, name, O_CREAT | O_WRONLY, 0700);
+ file = file_open_root_mnt(mnt, name, O_CREAT | O_WRONLY, 0700);
if (IS_ERR(file)) {
mntput(mnt);
return ERR_CAST(file);
--
2.11.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/4] take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space
2021-06-08 11:39 ` [PATCH 1/4] switch file_open_root() to struct path Al Viro
@ 2021-06-08 11:39 ` Al Viro
2021-06-08 11:39 ` [PATCH 3/4] teach set_nameidata() to handle setting the root as well Al Viro
2021-06-08 11:39 ` [PATCH 4/4] namei: make sure nd->depth is always valid Al Viro
2 siblings, 0 replies; 6+ messages in thread
From: Al Viro @ 2021-06-08 11:39 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
Separate field in nameidata (nd->state) holding the flags that
should be internal-only - that way we both get some spare bits
in LOOKUP_... and get simpler rules for nd->root lifetime rules,
since we can set the replacement of LOOKUP_ROOT (ND_ROOT_PRESET)
at the same time we set nd->root.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
Documentation/filesystems/path-lookup.rst | 6 ++--
fs/namei.c | 54 ++++++++++++++++++-------------
fs/nfs/nfstrace.h | 4 ---
include/linux/namei.h | 3 --
4 files changed, 34 insertions(+), 33 deletions(-)
diff --git a/Documentation/filesystems/path-lookup.rst b/Documentation/filesystems/path-lookup.rst
index c482e1619e77..ede67f705787 100644
--- a/Documentation/filesystems/path-lookup.rst
+++ b/Documentation/filesystems/path-lookup.rst
@@ -1321,18 +1321,18 @@ to lookup: RCU-walk, REF-walk, and REF-walk with forced revalidation.
yet. This is primarily used to tell the audit subsystem the full
context of a particular access being audited.
-``LOOKUP_ROOT`` indicates that the ``root`` field in the ``nameidata`` was
+``ND_ROOT_PRESET`` indicates that the ``root`` field in the ``nameidata`` was
provided by the caller, so it shouldn't be released when it is no
longer needed.
-``LOOKUP_JUMPED`` means that the current dentry was chosen not because
+``ND_JUMPED`` means that the current dentry was chosen not because
it had the right name but for some other reason. This happens when
following "``..``", following a symlink to ``/``, crossing a mount point
or accessing a "``/proc/$PID/fd/$FD``" symlink (also known as a "magic
link"). In this case the filesystem has not been asked to revalidate the
name (with ``d_revalidate()``). In such cases the inode may still need
to be revalidated, so ``d_op->d_weak_revalidate()`` is called if
-``LOOKUP_JUMPED`` is set when the look completes - which may be at the
+``ND_JUMPED`` is set when the look completes - which may be at the
final component or, when creating, unlinking, or renaming, at the penultimate component.
Resolution-restriction flags
diff --git a/fs/namei.c b/fs/namei.c
index 4b6cf4974dd7..622b9f15bf1c 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -554,7 +554,7 @@ struct nameidata {
struct qstr last;
struct path root;
struct inode *inode; /* path.dentry.d_inode */
- unsigned int flags;
+ unsigned int flags, state;
unsigned seq, m_seq, r_seq;
int last_type;
unsigned depth;
@@ -573,6 +573,10 @@ struct nameidata {
umode_t dir_mode;
} __randomize_layout;
+#define ND_ROOT_PRESET 1
+#define ND_ROOT_GRABBED 2
+#define ND_JUMPED 4
+
static void set_nameidata(struct nameidata *p, int dfd, struct filename *name)
{
struct nameidata *old = current->nameidata;
@@ -583,6 +587,7 @@ static void set_nameidata(struct nameidata *p, int dfd, struct filename *name)
p->path.dentry = NULL;
p->total_link_count = old ? old->total_link_count : 0;
p->saved = old;
+ p->state = 0;
current->nameidata = p;
}
@@ -645,9 +650,9 @@ static void terminate_walk(struct nameidata *nd)
path_put(&nd->path);
for (i = 0; i < nd->depth; i++)
path_put(&nd->stack[i].link);
- if (nd->flags & LOOKUP_ROOT_GRABBED) {
+ if (nd->state & ND_ROOT_GRABBED) {
path_put(&nd->root);
- nd->flags &= ~LOOKUP_ROOT_GRABBED;
+ nd->state &= ~ND_ROOT_GRABBED;
}
} else {
nd->flags &= ~LOOKUP_RCU;
@@ -710,9 +715,9 @@ static bool legitimize_root(struct nameidata *nd)
if (!nd->root.mnt && (nd->flags & LOOKUP_IS_SCOPED))
return false;
/* Nothing to do if nd->root is zero or is managed by the VFS user. */
- if (!nd->root.mnt || (nd->flags & LOOKUP_ROOT))
+ if (!nd->root.mnt || (nd->state & ND_ROOT_PRESET))
return true;
- nd->flags |= LOOKUP_ROOT_GRABBED;
+ nd->state |= ND_ROOT_GRABBED;
return legitimize_path(nd, &nd->root, nd->root_seq);
}
@@ -849,8 +854,9 @@ static int complete_walk(struct nameidata *nd)
* We don't want to zero nd->root for scoped-lookups or
* externally-managed nd->root.
*/
- if (!(nd->flags & (LOOKUP_ROOT | LOOKUP_IS_SCOPED)))
- nd->root.mnt = NULL;
+ if (!(nd->state & ND_ROOT_PRESET))
+ if (!(nd->flags & LOOKUP_IS_SCOPED))
+ nd->root.mnt = NULL;
nd->flags &= ~LOOKUP_CACHED;
if (!try_to_unlazy(nd))
return -ECHILD;
@@ -877,7 +883,7 @@ static int complete_walk(struct nameidata *nd)
return -EXDEV;
}
- if (likely(!(nd->flags & LOOKUP_JUMPED)))
+ if (likely(!(nd->state & ND_JUMPED)))
return 0;
if (likely(!(dentry->d_flags & DCACHE_OP_WEAK_REVALIDATE)))
@@ -915,7 +921,7 @@ static int set_root(struct nameidata *nd)
} while (read_seqcount_retry(&fs->seq, seq));
} else {
get_fs_root(fs, &nd->root);
- nd->flags |= LOOKUP_ROOT_GRABBED;
+ nd->state |= ND_ROOT_GRABBED;
}
return 0;
}
@@ -948,7 +954,7 @@ static int nd_jump_root(struct nameidata *nd)
path_get(&nd->path);
nd->inode = nd->path.dentry->d_inode;
}
- nd->flags |= LOOKUP_JUMPED;
+ nd->state |= ND_JUMPED;
return 0;
}
@@ -976,7 +982,7 @@ int nd_jump_link(struct path *path)
path_put(&nd->path);
nd->path = *path;
nd->inode = nd->path.dentry->d_inode;
- nd->flags |= LOOKUP_JUMPED;
+ nd->state |= ND_JUMPED;
return 0;
err:
@@ -1424,7 +1430,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
if (mounted) {
path->mnt = &mounted->mnt;
dentry = path->dentry = mounted->mnt.mnt_root;
- nd->flags |= LOOKUP_JUMPED;
+ nd->state |= ND_JUMPED;
*seqp = read_seqcount_begin(&dentry->d_seq);
*inode = dentry->d_inode;
/*
@@ -1469,7 +1475,7 @@ static inline int handle_mounts(struct nameidata *nd, struct dentry *dentry,
if (unlikely(nd->flags & LOOKUP_NO_XDEV))
ret = -EXDEV;
else
- nd->flags |= LOOKUP_JUMPED;
+ nd->state |= ND_JUMPED;
}
if (unlikely(ret)) {
dput(path->dentry);
@@ -2220,7 +2226,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
case 2:
if (name[1] == '.') {
type = LAST_DOTDOT;
- nd->flags |= LOOKUP_JUMPED;
+ nd->state |= ND_JUMPED;
}
break;
case 1:
@@ -2228,7 +2234,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
}
if (likely(type == LAST_NORM)) {
struct dentry *parent = nd->path.dentry;
- nd->flags &= ~LOOKUP_JUMPED;
+ nd->state &= ~ND_JUMPED;
if (unlikely(parent->d_flags & DCACHE_OP_HASH)) {
struct qstr this = { { .hash_len = hash_len }, .name = name };
err = parent->d_op->d_hash(parent, &this);
@@ -2302,14 +2308,15 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
if (flags & LOOKUP_RCU)
rcu_read_lock();
- nd->flags = flags | LOOKUP_JUMPED;
+ nd->flags = flags;
+ nd->state |= ND_JUMPED;
nd->depth = 0;
nd->m_seq = __read_seqcount_begin(&mount_lock.seqcount);
nd->r_seq = __read_seqcount_begin(&rename_lock.seqcount);
smp_rmb();
- if (flags & LOOKUP_ROOT) {
+ if (nd->state & ND_ROOT_PRESET) {
struct dentry *root = nd->root.dentry;
struct inode *inode = root->d_inode;
if (*s && unlikely(!d_can_lookup(root)))
@@ -2384,7 +2391,7 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
nd->root_seq = nd->seq;
} else {
path_get(&nd->root);
- nd->flags |= LOOKUP_ROOT_GRABBED;
+ nd->state |= ND_ROOT_GRABBED;
}
}
return s;
@@ -2423,7 +2430,7 @@ static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path
;
if (!err && unlikely(nd->flags & LOOKUP_MOUNTPOINT)) {
err = handle_lookup_down(nd);
- nd->flags &= ~LOOKUP_JUMPED; // no d_weak_revalidate(), please...
+ nd->state &= ~ND_JUMPED; // no d_weak_revalidate(), please...
}
if (!err)
err = complete_walk(nd);
@@ -2447,11 +2454,11 @@ int filename_lookup(int dfd, struct filename *name, unsigned flags,
struct nameidata nd;
if (IS_ERR(name))
return PTR_ERR(name);
+ set_nameidata(&nd, dfd, name);
if (unlikely(root)) {
nd.root = *root;
- flags |= LOOKUP_ROOT;
+ nd.state = ND_ROOT_PRESET;
}
- set_nameidata(&nd, dfd, name);
retval = path_lookupat(&nd, flags | LOOKUP_RCU, path);
if (unlikely(retval == -ECHILD))
retval = path_lookupat(&nd, flags, path);
@@ -3539,7 +3546,7 @@ struct file *do_file_open_root(const struct path *root,
struct nameidata nd;
struct file *file;
struct filename *filename;
- int flags = op->lookup_flags | LOOKUP_ROOT;
+ int flags = op->lookup_flags;
if (d_is_symlink(root->dentry) && op->intent & LOOKUP_OPEN)
return ERR_PTR(-ELOOP);
@@ -3548,8 +3555,9 @@ struct file *do_file_open_root(const struct path *root,
if (IS_ERR(filename))
return ERR_CAST(filename);
- nd.root = *root;
set_nameidata(&nd, -1, filename);
+ nd.root = *root;
+ nd.state = ND_ROOT_PRESET;
file = path_openat(&nd, op, flags | LOOKUP_RCU);
if (unlikely(file == ERR_PTR(-ECHILD)))
file = path_openat(&nd, op, flags);
diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h
index 5a59dcdce0b2..cb7f49723bbf 100644
--- a/fs/nfs/nfstrace.h
+++ b/fs/nfs/nfstrace.h
@@ -271,8 +271,6 @@ TRACE_DEFINE_ENUM(LOOKUP_OPEN);
TRACE_DEFINE_ENUM(LOOKUP_CREATE);
TRACE_DEFINE_ENUM(LOOKUP_EXCL);
TRACE_DEFINE_ENUM(LOOKUP_RENAME_TARGET);
-TRACE_DEFINE_ENUM(LOOKUP_JUMPED);
-TRACE_DEFINE_ENUM(LOOKUP_ROOT);
TRACE_DEFINE_ENUM(LOOKUP_EMPTY);
TRACE_DEFINE_ENUM(LOOKUP_DOWN);
@@ -288,8 +286,6 @@ TRACE_DEFINE_ENUM(LOOKUP_DOWN);
{ LOOKUP_CREATE, "CREATE" }, \
{ LOOKUP_EXCL, "EXCL" }, \
{ LOOKUP_RENAME_TARGET, "RENAME_TARGET" }, \
- { LOOKUP_JUMPED, "JUMPED" }, \
- { LOOKUP_ROOT, "ROOT" }, \
{ LOOKUP_EMPTY, "EMPTY" }, \
{ LOOKUP_DOWN, "DOWN" })
diff --git a/include/linux/namei.h b/include/linux/namei.h
index b9605b2b46e7..be9a2b349ca7 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -36,9 +36,6 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT};
/* internal use only */
#define LOOKUP_PARENT 0x0010
-#define LOOKUP_JUMPED 0x1000
-#define LOOKUP_ROOT 0x2000
-#define LOOKUP_ROOT_GRABBED 0x0008
/* Scoping flags for lookup. */
#define LOOKUP_NO_SYMLINKS 0x010000 /* No symlink crossing. */
--
2.11.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 3/4] teach set_nameidata() to handle setting the root as well
2021-06-08 11:39 ` [PATCH 1/4] switch file_open_root() to struct path Al Viro
2021-06-08 11:39 ` [PATCH 2/4] take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space Al Viro
@ 2021-06-08 11:39 ` Al Viro
2021-06-08 11:39 ` [PATCH 4/4] namei: make sure nd->depth is always valid Al Viro
2 siblings, 0 replies; 6+ messages in thread
From: Al Viro @ 2021-06-08 11:39 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
That way we don't need the callers to mess with manually setting any fields
of nameidata instances. Old set_nameidata() gets renamed (__set_nameidata()),
new becomes an inlined helper that takes a struct path pointer and deals
with setting nd->root and putting ND_ROOT_PRESET in nd->state when new
argument is non-NULL.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 622b9f15bf1c..40ffb249aa7f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -577,7 +577,7 @@ struct nameidata {
#define ND_ROOT_GRABBED 2
#define ND_JUMPED 4
-static void set_nameidata(struct nameidata *p, int dfd, struct filename *name)
+static void __set_nameidata(struct nameidata *p, int dfd, struct filename *name)
{
struct nameidata *old = current->nameidata;
p->stack = p->internal;
@@ -587,10 +587,20 @@ static void set_nameidata(struct nameidata *p, int dfd, struct filename *name)
p->path.dentry = NULL;
p->total_link_count = old ? old->total_link_count : 0;
p->saved = old;
- p->state = 0;
current->nameidata = p;
}
+static inline void set_nameidata(struct nameidata *p, int dfd, struct filename *name,
+ const struct path *root)
+{
+ __set_nameidata(p, dfd, name);
+ p->state = 0;
+ if (unlikely(root)) {
+ p->state = ND_ROOT_PRESET;
+ p->root = *root;
+ }
+}
+
static void restore_nameidata(void)
{
struct nameidata *now = current->nameidata, *old = now->saved;
@@ -2454,11 +2464,7 @@ int filename_lookup(int dfd, struct filename *name, unsigned flags,
struct nameidata nd;
if (IS_ERR(name))
return PTR_ERR(name);
- set_nameidata(&nd, dfd, name);
- if (unlikely(root)) {
- nd.root = *root;
- nd.state = ND_ROOT_PRESET;
- }
+ set_nameidata(&nd, dfd, name, root);
retval = path_lookupat(&nd, flags | LOOKUP_RCU, path);
if (unlikely(retval == -ECHILD))
retval = path_lookupat(&nd, flags, path);
@@ -2499,7 +2505,7 @@ static struct filename *filename_parentat(int dfd, struct filename *name,
if (IS_ERR(name))
return name;
- set_nameidata(&nd, dfd, name);
+ set_nameidata(&nd, dfd, name, NULL);
retval = path_parentat(&nd, flags | LOOKUP_RCU, parent);
if (unlikely(retval == -ECHILD))
retval = path_parentat(&nd, flags, parent);
@@ -3530,7 +3536,7 @@ struct file *do_filp_open(int dfd, struct filename *pathname,
int flags = op->lookup_flags;
struct file *filp;
- set_nameidata(&nd, dfd, pathname);
+ set_nameidata(&nd, dfd, pathname, NULL);
filp = path_openat(&nd, op, flags | LOOKUP_RCU);
if (unlikely(filp == ERR_PTR(-ECHILD)))
filp = path_openat(&nd, op, flags);
@@ -3555,9 +3561,7 @@ struct file *do_file_open_root(const struct path *root,
if (IS_ERR(filename))
return ERR_CAST(filename);
- set_nameidata(&nd, -1, filename);
- nd.root = *root;
- nd.state = ND_ROOT_PRESET;
+ set_nameidata(&nd, -1, filename, root);
file = path_openat(&nd, op, flags | LOOKUP_RCU);
if (unlikely(file == ERR_PTR(-ECHILD)))
file = path_openat(&nd, op, flags);
--
2.11.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 4/4] namei: make sure nd->depth is always valid
2021-06-08 11:39 ` [PATCH 1/4] switch file_open_root() to struct path Al Viro
2021-06-08 11:39 ` [PATCH 2/4] take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space Al Viro
2021-06-08 11:39 ` [PATCH 3/4] teach set_nameidata() to handle setting the root as well Al Viro
@ 2021-06-08 11:39 ` Al Viro
2 siblings, 0 replies; 6+ messages in thread
From: Al Viro @ 2021-06-08 11:39 UTC (permalink / raw)
To: linux-fsdevel; +Cc: linux-kernel
Zero it in set_nameidata() rather than in path_init(). That way
it always matches the number of valid nd->stack[] entries.
Since terminate_walk() does zero it (after having emptied the
stack), we don't need to reinitialize it in subsequent path_init().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/namei.c b/fs/namei.c
index 40ffb249aa7f..d38b17ad604c 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -581,6 +581,7 @@ static void __set_nameidata(struct nameidata *p, int dfd, struct filename *name)
{
struct nameidata *old = current->nameidata;
p->stack = p->internal;
+ p->depth = 0;
p->dfd = dfd;
p->name = name;
p->path.mnt = NULL;
@@ -2320,7 +2321,6 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
nd->flags = flags;
nd->state |= ND_JUMPED;
- nd->depth = 0;
nd->m_seq = __read_seqcount_begin(&mount_lock.seqcount);
nd->r_seq = __read_seqcount_begin(&rename_lock.seqcount);
--
2.11.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCHES] namei cleanups
2021-06-08 11:38 [PATCHES] namei cleanups Al Viro
2021-06-08 11:39 ` [PATCH 1/4] switch file_open_root() to struct path Al Viro
@ 2021-06-08 12:12 ` Christian Brauner
1 sibling, 0 replies; 6+ messages in thread
From: Christian Brauner @ 2021-06-08 12:12 UTC (permalink / raw)
To: Al Viro; +Cc: linux-fsdevel, linux-kernel
On Tue, Jun 08, 2021 at 11:38:40AM +0000, Al Viro wrote:
> Small namei.c patch series, mostly to simplify the rules
> for nameidata state. It's in #work.namei and it's actually from
> the previous cycle - didn't post it for review in time...
>
> Changes visible outside of fs/namei.c: file_open_root()
> calling conventions change, some freed bits in LOOKUP_... space.
Ah that's the follow-up to the io_uring fix from last cycle.
Nice cleanup.
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-06-08 12:12 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-06-08 11:38 [PATCHES] namei cleanups Al Viro
2021-06-08 11:39 ` [PATCH 1/4] switch file_open_root() to struct path Al Viro
2021-06-08 11:39 ` [PATCH 2/4] take LOOKUP_{ROOT,ROOT_GRABBED,JUMPED} out of LOOKUP_... space Al Viro
2021-06-08 11:39 ` [PATCH 3/4] teach set_nameidata() to handle setting the root as well Al Viro
2021-06-08 11:39 ` [PATCH 4/4] namei: make sure nd->depth is always valid Al Viro
2021-06-08 12:12 ` [PATCHES] namei cleanups Christian Brauner
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