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Subject[25/93] freeze_bdev: dont deactivate successfully frozen MS_RDONLY sb
2.6.32-stable review patch.  If anyone has any objections, please let us know.


From: Jun'ichi Nomura <>

commit 4b06e5b9ad8abb20105b2b25e42c509ebe9b2d76 upstream.

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
Also, keep sb->s_frozen consistent so that remount can check the frozen state.

Otherwise a crash reported here can happen:

This patch should be applied for 2.6.32 stable series, too.

Reviewed-by: Christoph Hellwig <>
Tested-by: Thomas Backlund <>
Signed-off-by: Jun'ichi Nomura <>
Signed-off-by: Al Viro <>
Signed-off-by: Greg Kroah-Hartman <>

--- 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);
return sb;
@@ -307,7 +308,7 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb)
BUG_ON(sb->s_bdev != bdev);
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)

sb->s_frozen = SB_UNFROZEN;

if (sb)

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