* [RFC][PATCH] ckpt-files: error out on file locks and leases
@ 2009-12-17 17:35 Dave Hansen
[not found] ` <1261071313-14162-1-git-send-email-dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
0 siblings, 1 reply; 2+ messages in thread
From: Dave Hansen @ 2009-12-17 17:35 UTC (permalink / raw)
To: containers-cunTk1MwBs98uUxBSJOaYoYkZiVZrdSR2LY78lusg7I; +Cc: Dave Hansen
We do not currently handle the holding of any file locks.
If a process being checkpointed is holding one, error out
of the checkpoint process.
Signed-off-by: Dave Hansen <dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
---
checkpoint/files.c | 12 ++++++++++++
fs/locks.c | 35 +++++++++++++++++++++++++++++++++++
include/linux/fs.h | 6 ++++++
3 files changed, 53 insertions(+), 0 deletions(-)
diff --git a/checkpoint/files.c b/checkpoint/files.c
index b622588..46a103d 100644
--- a/checkpoint/files.c
+++ b/checkpoint/files.c
@@ -272,6 +272,18 @@ static int checkpoint_file_desc(struct ckpt_ctx *ctx,
}
rcu_read_unlock();
+ ret = find_locks_with_owner(file, files);
+ /*
+ * find_locks_with_owner() returns an error when there
+ * are no locks found, so we *want* it to return an error
+ * code. Its success means we have to fail the checkpoint.
+ */
+ if (!ret) {
+ ret = -EBADF;
+ ckpt_err(ctx, ret, "%(T)fd %d has file lock or lease\n", fd);
+ goto out;
+ }
+
/* sanity check (although this shouldn't happen) */
ret = -EBADF;
if (!file) {
diff --git a/fs/locks.c b/fs/locks.c
index a8794f2..721481a 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1994,6 +1994,41 @@ void locks_remove_posix(struct file *filp, fl_owner_t owner)
EXPORT_SYMBOL(locks_remove_posix);
+int find_locks_with_owner(struct file *filp, fl_owner_t owner)
+{
+ struct inode *inode = filp->f_path.dentry->d_inode;
+ struct file_lock **inode_fl;
+ int ret = -EEXIST;
+
+ lock_kernel();
+ for_each_lock(inode, inode_fl) {
+ struct file_lock *fl = *inode_fl;
+ /*
+ * We could use posix_same_owner() along with a 'fake'
+ * file_lock. But, the fake file will never have the
+ * same fl_lmops as the fl that we are looking for and
+ * posix_same_owner() would just fall back to this
+ * check anyway.
+ */
+ if (IS_POSIX(fl)) {
+ if (fl->fl_owner == owner) {
+ ret = 0;
+ break;
+ }
+ } else if (IS_FLOCK(fl) || IS_LEASE(fl)) {
+ if (fl->fl_file == filp) {
+ ret = 0;
+ break;
+ }
+ } else {
+ WARN(1, "unknown file lock type, fl_flags: %x",
+ fl->fl_flags);
+ }
+ }
+ unlock_kernel();
+ return ret;
+}
+
/*
* This function is called on the last close of an open file.
*/
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5ae34fc..089549b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1122,6 +1122,7 @@ extern void locks_remove_posix(struct file *, fl_owner_t);
extern void locks_remove_flock(struct file *);
extern void locks_release_private(struct file_lock *);
extern void posix_test_lock(struct file *, struct file_lock *);
+extern int find_locks_with_owner(struct file *filp, fl_owner_t owner);
extern int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
extern int posix_lock_file_wait(struct file *, struct file_lock *);
extern int posix_unblock_lock(struct file *, struct file_lock *);
@@ -1190,6 +1191,11 @@ static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
return;
}
+static inline int find_locks_with_owner(struct file *filp, fl_owner_t owner)
+{
+ return -ENOENT;
+}
+
static inline void locks_remove_flock(struct file *filp)
{
return;
--
1.6.6.rc3
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [RFC][PATCH] ckpt-files: error out on file locks and leases
[not found] ` <1261071313-14162-1-git-send-email-dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
@ 2009-12-18 15:47 ` Serge E. Hallyn
0 siblings, 0 replies; 2+ messages in thread
From: Serge E. Hallyn @ 2009-12-18 15:47 UTC (permalink / raw)
To: Dave Hansen; +Cc: containers-cunTk1MwBs98uUxBSJOaYoYkZiVZrdSR2LY78lusg7I
Quoting Dave Hansen (dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org):
> We do not currently handle the holding of any file locks.
> If a process being checkpointed is holding one, error out
> of the checkpoint process.
>
> Signed-off-by: Dave Hansen <dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
Acked-by: Serge Hallyn <serue-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
Thanks, Dave. Applied to branch cr-next at
git://git.kernel.org/pub/scm/linux/kernel/git/sergeh/linux-cr.git
(as soon as it mirrors)
So, I think that as of the unimplemented features listed on
http://ckpt.wiki.kernel.org/index.php/Checklist, my cr-next
branch properly refuses to checkpoint all of them except for
sysvipc semaphore undos (which are supposed to be trivial
to implement?) and hardware devices - for which we can claim
that any controls through an fs interface will cause checkpoint
refusal.
So are we happy at this point?
thanks,
-serge
> ---
> checkpoint/files.c | 12 ++++++++++++
> fs/locks.c | 35 +++++++++++++++++++++++++++++++++++
> include/linux/fs.h | 6 ++++++
> 3 files changed, 53 insertions(+), 0 deletions(-)
>
> diff --git a/checkpoint/files.c b/checkpoint/files.c
> index b622588..46a103d 100644
> --- a/checkpoint/files.c
> +++ b/checkpoint/files.c
> @@ -272,6 +272,18 @@ static int checkpoint_file_desc(struct ckpt_ctx *ctx,
> }
> rcu_read_unlock();
>
> + ret = find_locks_with_owner(file, files);
> + /*
> + * find_locks_with_owner() returns an error when there
> + * are no locks found, so we *want* it to return an error
> + * code. Its success means we have to fail the checkpoint.
> + */
> + if (!ret) {
> + ret = -EBADF;
> + ckpt_err(ctx, ret, "%(T)fd %d has file lock or lease\n", fd);
> + goto out;
> + }
> +
> /* sanity check (although this shouldn't happen) */
> ret = -EBADF;
> if (!file) {
> diff --git a/fs/locks.c b/fs/locks.c
> index a8794f2..721481a 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -1994,6 +1994,41 @@ void locks_remove_posix(struct file *filp, fl_owner_t owner)
>
> EXPORT_SYMBOL(locks_remove_posix);
>
> +int find_locks_with_owner(struct file *filp, fl_owner_t owner)
> +{
> + struct inode *inode = filp->f_path.dentry->d_inode;
> + struct file_lock **inode_fl;
> + int ret = -EEXIST;
> +
> + lock_kernel();
> + for_each_lock(inode, inode_fl) {
> + struct file_lock *fl = *inode_fl;
> + /*
> + * We could use posix_same_owner() along with a 'fake'
> + * file_lock. But, the fake file will never have the
> + * same fl_lmops as the fl that we are looking for and
> + * posix_same_owner() would just fall back to this
> + * check anyway.
> + */
> + if (IS_POSIX(fl)) {
> + if (fl->fl_owner == owner) {
> + ret = 0;
> + break;
> + }
> + } else if (IS_FLOCK(fl) || IS_LEASE(fl)) {
> + if (fl->fl_file == filp) {
> + ret = 0;
> + break;
> + }
> + } else {
> + WARN(1, "unknown file lock type, fl_flags: %x",
> + fl->fl_flags);
> + }
> + }
> + unlock_kernel();
> + return ret;
> +}
> +
> /*
> * This function is called on the last close of an open file.
> */
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 5ae34fc..089549b 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1122,6 +1122,7 @@ extern void locks_remove_posix(struct file *, fl_owner_t);
> extern void locks_remove_flock(struct file *);
> extern void locks_release_private(struct file_lock *);
> extern void posix_test_lock(struct file *, struct file_lock *);
> +extern int find_locks_with_owner(struct file *filp, fl_owner_t owner);
> extern int posix_lock_file(struct file *, struct file_lock *, struct file_lock *);
> extern int posix_lock_file_wait(struct file *, struct file_lock *);
> extern int posix_unblock_lock(struct file *, struct file_lock *);
> @@ -1190,6 +1191,11 @@ static inline void locks_remove_posix(struct file *filp, fl_owner_t owner)
> return;
> }
>
> +static inline int find_locks_with_owner(struct file *filp, fl_owner_t owner)
> +{
> + return -ENOENT;
> +}
> +
> static inline void locks_remove_flock(struct file *filp)
> {
> return;
> --
> 1.6.6.rc3
>
> _______________________________________________
> Containers mailing list
> Containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
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2009-12-17 17:35 [RFC][PATCH] ckpt-files: error out on file locks and leases Dave Hansen
[not found] ` <1261071313-14162-1-git-send-email-dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2009-12-18 15:47 ` Serge E. Hallyn
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