diff options
| author | Jun'ichi Nomura <j-nomura@ce.jp.nec.com> | 2010-01-29 09:56:22 +0900 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2010-02-07 03:06:21 -0500 |
| commit | 4b06e5b9ad8abb20105b2b25e42c509ebe9b2d76 (patch) | |
| tree | a151e21fef671e9d046a6c456d2f048eea56fb99 | |
| parent | 8dd5ca532c2d2c2b85f16bc038ebfff05b8853e1 (diff) | |
freeze_bdev: don't deactivate successfully frozen MS_RDONLY sb
Thanks Thomas and Christoph for testing and review.
I removed 'smp_wmb()' before up_write from the previous patch,
since up_write() should have necessary ordering constraints.
(I.e. the change of s_frozen is visible to others after up_write)
I'm quite sure the change is harmless but if you are uncomfortable
with Tested-by/Reviewed-by on the modified patch, please remove them.
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
This patch should be applied for 2.6.32 stable series, too.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Thomas Backlund <tmb@mandriva.org>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: stable@kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/block_dev.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 73d6a735b8f..d11d0289f3d 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -246,7 +246,8 @@ struct super_block *freeze_bdev(struct block_device *bdev) 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, struct super_block *sb) 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, struct super_block *sb) } } +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: |