* [PATCH] fs: ioctl_fsthaw should use freeze_bdev if possible
@ 2013-03-21 12:26 Dmitry Monakhov
2013-04-10 17:57 ` [PATCH] fs: ioctl_fsthaw should use freeze_bdev if PING Dmitry Monakhov
0 siblings, 1 reply; 3+ messages in thread
From: Dmitry Monakhov @ 2013-03-21 12:26 UTC (permalink / raw)
To: linux-fsdevel; +Cc: viro, josef, Dmitry Monakhov
Commit: 18e9e5104fcd breaks connection between freeze_bdev()/thaw_bdev() and
freeze_super()/thaw_super()
In other workds:
freeze_bdev()/thaw_bdev() may be called multiple times, but
freeze_super()/thaw_super() only once (will resunt -EBUSY on second call)
BUT user is still allowed to mix both interfaces:
freeze_bdev () call it first time
->bdev->bd_fsfreeze_count++
->freeze_super()
return 0
freeze_super() second time
->bdev->bd_fsfreeze_count++
return 0
One can call ioctl_fsthaw( #xfs_freeze -u $MNT)
ioctl_fsthaw
->thaw_super() -> fs is unfrozen now
return 0
This leave bdev in broken state because:
bd_fsfreeze_count > 0 but superblock is not frozen.
Visiable effect:
0) Any freeze_bdev() will not call freeze_super() because
(bdev->bd_fsfreeze_count > 0)
1) thaw_bdev() will fail because thaw_super() will return EINVAL (filesystem
is not frozen) and bdev->bd_fsfreeze_count will not being decremented.
2) filesystem may not being mounted because mount_bdev will fail
because (bdev->bd_fsfreeze_count > 0)
#TEST_CASE:
# Use xfstests 068'th test
(while true ;do dmsetup suspend $SCRATCH_DEV ;dmsetup resume $SCRATCH_DEV;done)&
pid=$!
./check 068 068 068 068 068
kill $pid
wait $pid
In order to fix that let's always use {freeze,thaw}_bdev() functions if
super block has bdev, and directly call {freeze,thaw)_super() otherwise.
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
---
fs/ioctl.c | 16 +++++++++++++---
1 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 3bdad6d..ea47ccc 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -513,6 +513,7 @@ static int ioctl_fioasync(unsigned int fd, struct file *filp,
static int ioctl_fsfreeze(struct file *filp)
{
struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;
+ int ret = 0;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
@@ -521,8 +522,15 @@ static int ioctl_fsfreeze(struct file *filp)
if (sb->s_op->freeze_fs == NULL)
return -EOPNOTSUPP;
- /* Freeze */
- return freeze_super(sb);
+ if (sb->s_bdev) {
+ struct super_block *fsb;
+ fsb = freeze_bdev(sb->s_bdev);
+ if (IS_ERR(fsb))
+ ret = PTR_ERR(fsb);
+ } else {
+ ret = freeze_super(sb);
+ }
+ return ret;
}
static int ioctl_fsthaw(struct file *filp)
@@ -532,7 +540,9 @@ static int ioctl_fsthaw(struct file *filp)
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- /* Thaw */
+ if (sb->s_bdev)
+ return thaw_bdev(sb->s_bdev, sb);
+
return thaw_super(sb);
}
--
1.7.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] fs: ioctl_fsthaw should use freeze_bdev if PING.
2013-03-21 12:26 [PATCH] fs: ioctl_fsthaw should use freeze_bdev if possible Dmitry Monakhov
@ 2013-04-10 17:57 ` Dmitry Monakhov
2013-04-10 21:28 ` Jan Kara
0 siblings, 1 reply; 3+ messages in thread
From: Dmitry Monakhov @ 2013-04-10 17:57 UTC (permalink / raw)
To: linux-fsdevel; +Cc: viro, josef
On Thu, 21 Mar 2013 16:26:56 +0400, Dmitry Monakhov <dmonakhov@openvz.org> wrote:
Ping... Please take a look at this fix.
> Commit: 18e9e5104fcd breaks connection between freeze_bdev()/thaw_bdev() and
> freeze_super()/thaw_super()
> In other workds:
> freeze_bdev()/thaw_bdev() may be called multiple times, but
> freeze_super()/thaw_super() only once (will resunt -EBUSY on second call)
>
> BUT user is still allowed to mix both interfaces:
>
> freeze_bdev () call it first time
> ->bdev->bd_fsfreeze_count++
> ->freeze_super()
> return 0
> freeze_super() second time
> ->bdev->bd_fsfreeze_count++
> return 0
>
> One can call ioctl_fsthaw( #xfs_freeze -u $MNT)
> ioctl_fsthaw
> ->thaw_super() -> fs is unfrozen now
> return 0
>
> This leave bdev in broken state because:
> bd_fsfreeze_count > 0 but superblock is not frozen.
> Visiable effect:
> 0) Any freeze_bdev() will not call freeze_super() because
> (bdev->bd_fsfreeze_count > 0)
> 1) thaw_bdev() will fail because thaw_super() will return EINVAL (filesystem
> is not frozen) and bdev->bd_fsfreeze_count will not being decremented.
> 2) filesystem may not being mounted because mount_bdev will fail
> because (bdev->bd_fsfreeze_count > 0)
>
> #TEST_CASE:
> # Use xfstests 068'th test
> (while true ;do dmsetup suspend $SCRATCH_DEV ;dmsetup resume $SCRATCH_DEV;done)&
> pid=$!
> ./check 068 068 068 068 068
> kill $pid
> wait $pid
>
> In order to fix that let's always use {freeze,thaw}_bdev() functions if
> super block has bdev, and directly call {freeze,thaw)_super() otherwise.
>
> Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
> ---
> fs/ioctl.c | 16 +++++++++++++---
> 1 files changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/fs/ioctl.c b/fs/ioctl.c
> index 3bdad6d..ea47ccc 100644
> --- a/fs/ioctl.c
> +++ b/fs/ioctl.c
> @@ -513,6 +513,7 @@ static int ioctl_fioasync(unsigned int fd, struct file *filp,
> static int ioctl_fsfreeze(struct file *filp)
> {
> struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;
> + int ret = 0;
>
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
> @@ -521,8 +522,15 @@ static int ioctl_fsfreeze(struct file *filp)
> if (sb->s_op->freeze_fs == NULL)
> return -EOPNOTSUPP;
>
> - /* Freeze */
> - return freeze_super(sb);
> + if (sb->s_bdev) {
> + struct super_block *fsb;
> + fsb = freeze_bdev(sb->s_bdev);
> + if (IS_ERR(fsb))
> + ret = PTR_ERR(fsb);
> + } else {
> + ret = freeze_super(sb);
> + }
> + return ret;
> }
>
> static int ioctl_fsthaw(struct file *filp)
> @@ -532,7 +540,9 @@ static int ioctl_fsthaw(struct file *filp)
> if (!capable(CAP_SYS_ADMIN))
> return -EPERM;
>
> - /* Thaw */
> + if (sb->s_bdev)
> + return thaw_bdev(sb->s_bdev, sb);
> +
> return thaw_super(sb);
> }
>
> --
> 1.7.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] fs: ioctl_fsthaw should use freeze_bdev if PING.
2013-04-10 17:57 ` [PATCH] fs: ioctl_fsthaw should use freeze_bdev if PING Dmitry Monakhov
@ 2013-04-10 21:28 ` Jan Kara
0 siblings, 0 replies; 3+ messages in thread
From: Jan Kara @ 2013-04-10 21:28 UTC (permalink / raw)
To: Dmitry Monakhov; +Cc: linux-fsdevel, viro, josef
On Wed 10-04-13 21:57:37, Dmitry Monakhov wrote:
> On Thu, 21 Mar 2013 16:26:56 +0400, Dmitry Monakhov <dmonakhov@openvz.org> wrote:
> Ping... Please take a look at this fix.
Actually, there are much more issues in this area. Fernando fixed most of
them in his patch set (last posting is here
http://www.spinics.net/lists/linux-fsdevel/msg61266.html
I think) but it never got merged...
Honza
> > Commit: 18e9e5104fcd breaks connection between freeze_bdev()/thaw_bdev() and
> > freeze_super()/thaw_super()
> > In other workds:
> > freeze_bdev()/thaw_bdev() may be called multiple times, but
> > freeze_super()/thaw_super() only once (will resunt -EBUSY on second call)
> >
> > BUT user is still allowed to mix both interfaces:
> >
> > freeze_bdev () call it first time
> > ->bdev->bd_fsfreeze_count++
> > ->freeze_super()
> > return 0
> > freeze_super() second time
> > ->bdev->bd_fsfreeze_count++
> > return 0
> >
> > One can call ioctl_fsthaw( #xfs_freeze -u $MNT)
> > ioctl_fsthaw
> > ->thaw_super() -> fs is unfrozen now
> > return 0
> >
> > This leave bdev in broken state because:
> > bd_fsfreeze_count > 0 but superblock is not frozen.
> > Visiable effect:
> > 0) Any freeze_bdev() will not call freeze_super() because
> > (bdev->bd_fsfreeze_count > 0)
> > 1) thaw_bdev() will fail because thaw_super() will return EINVAL (filesystem
> > is not frozen) and bdev->bd_fsfreeze_count will not being decremented.
> > 2) filesystem may not being mounted because mount_bdev will fail
> > because (bdev->bd_fsfreeze_count > 0)
> >
> > #TEST_CASE:
> > # Use xfstests 068'th test
> > (while true ;do dmsetup suspend $SCRATCH_DEV ;dmsetup resume $SCRATCH_DEV;done)&
> > pid=$!
> > ./check 068 068 068 068 068
> > kill $pid
> > wait $pid
> >
> > In order to fix that let's always use {freeze,thaw}_bdev() functions if
> > super block has bdev, and directly call {freeze,thaw)_super() otherwise.
> >
> > Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
> > ---
> > fs/ioctl.c | 16 +++++++++++++---
> > 1 files changed, 13 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/ioctl.c b/fs/ioctl.c
> > index 3bdad6d..ea47ccc 100644
> > --- a/fs/ioctl.c
> > +++ b/fs/ioctl.c
> > @@ -513,6 +513,7 @@ static int ioctl_fioasync(unsigned int fd, struct file *filp,
> > static int ioctl_fsfreeze(struct file *filp)
> > {
> > struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;
> > + int ret = 0;
> >
> > if (!capable(CAP_SYS_ADMIN))
> > return -EPERM;
> > @@ -521,8 +522,15 @@ static int ioctl_fsfreeze(struct file *filp)
> > if (sb->s_op->freeze_fs == NULL)
> > return -EOPNOTSUPP;
> >
> > - /* Freeze */
> > - return freeze_super(sb);
> > + if (sb->s_bdev) {
> > + struct super_block *fsb;
> > + fsb = freeze_bdev(sb->s_bdev);
> > + if (IS_ERR(fsb))
> > + ret = PTR_ERR(fsb);
> > + } else {
> > + ret = freeze_super(sb);
> > + }
> > + return ret;
> > }
> >
> > static int ioctl_fsthaw(struct file *filp)
> > @@ -532,7 +540,9 @@ static int ioctl_fsthaw(struct file *filp)
> > if (!capable(CAP_SYS_ADMIN))
> > return -EPERM;
> >
> > - /* Thaw */
> > + if (sb->s_bdev)
> > + return thaw_bdev(sb->s_bdev, sb);
> > +
> > return thaw_super(sb);
> > }
> >
> > --
> > 1.7.1
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-03-21 12:26 [PATCH] fs: ioctl_fsthaw should use freeze_bdev if possible Dmitry Monakhov
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2013-04-10 21:28 ` Jan Kara
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