The patch titled
freeze_bdev(): don't deactivate successfully frozen MS_RDONLY sb
has been added to the -mm tree. Its filename is
freeze_bdev-dont-deactivate-successfully-frozen-ms_rdonly-sb.patch
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------------------------------------------------------
Subject: freeze_bdev(): don't deactivate successfully frozen MS_RDONLY sb
From: "Jun'ichi Nomura" <j-nomura@xxxxxxxxxxxxx>
If MS_RDONLY, freeze_bdev should just up_write(s_umount) instead of
deactivate_locked_super().
Also, keep sb->s_frozen consistent so that remount can check the frozen
state.
Otherwise a crash reported here can happen:
http://lkml.org/lkml/2010/1/16/37
http://lkml.org/lkml/2010/1/28/53
Thanks Thomas and Christoph for testing and review.
Signed-off-by: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Tested-by: Thomas Backlund <tmb@xxxxxxxxxxxx>
Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
Cc: Neil Brown <neilb@xxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx> [2.6.32.x]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/block_dev.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff -puN fs/block_dev.c~freeze_bdev-dont-deactivate-successfully-frozen-ms_rdonly-sb fs/block_dev.c
--- a/fs/block_dev.c~freeze_bdev-dont-deactivate-successfully-frozen-ms_rdonly-sb
+++ a/fs/block_dev.c
@@ -246,7 +246,8 @@ struct super_block *freeze_bdev(struct b
if (!sb)
goto out;
if (sb->s_flags & MS_RDONLY) {
- deactivate_locked_super(sb);
+ sb->s_frozen = SB_FREEZE_TRANS;
+ up_write(&sb->s_umount);
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return sb;
}
@@ -307,7 +308,7 @@ int thaw_bdev(struct block_device *bdev,
BUG_ON(sb->s_bdev != bdev);
down_write(&sb->s_umount);
if (sb->s_flags & MS_RDONLY)
- goto out_deactivate;
+ goto out_unfrozen;
if (sb->s_op->unfreeze_fs) {
error = sb->s_op->unfreeze_fs(sb);
@@ -321,11 +322,11 @@ int thaw_bdev(struct block_device *bdev,
}
}
+out_unfrozen:
sb->s_frozen = SB_UNFROZEN;
smp_wmb();
wake_up(&sb->s_wait_unfrozen);
-out_deactivate:
if (sb)
deactivate_locked_super(sb);
out_unlock:
_
Patches currently in -mm which might be from j-nomura@xxxxxxxxxxxxx are
linux-next.patch
freeze_bdev-dont-deactivate-successfully-frozen-ms_rdonly-sb.patch
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