freeze_bdev() with the device which is mounted as read only
does not change sb->s_frozen from SB_UNFROZEN to SB_FREEZE_TRANS.
Because of this behavior, xfs_freeze can break read-only XFS filesystem.
Because xfs_thaw does nothing for the filesystem whose sb->s_frozen is
SB_UNFROZEN. So freezed readonly XFS filesystem will never be unfreezed.
Then we cannot do any unmount/remount operations for that filesystem.
This patch updates sb->s_frozen when freeze_bdev() is called for read-only
mounted device, too.
Cc: Tim Shimmin <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: Akinobu Mita <[email protected]>
---
fs/buffer.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
Index: 2.6-git/fs/buffer.c
===================================================================
--- 2.6-git.orig/fs/buffer.c
+++ 2.6-git/fs/buffer.c
@@ -190,19 +190,22 @@ struct super_block *freeze_bdev(struct b
down(&bdev->bd_mount_sem);
sb = get_super(bdev);
- if (sb && !(sb->s_flags & MS_RDONLY)) {
+ if (sb) {
sb->s_frozen = SB_FREEZE_WRITE;
smp_wmb();
- __fsync_super(sb);
+ if (!(sb->s_flags & MS_RDONLY))
+ __fsync_super(sb);
sb->s_frozen = SB_FREEZE_TRANS;
smp_wmb();
- sync_blockdev(sb->s_bdev);
+ if (!(sb->s_flags & MS_RDONLY)) {
+ sync_blockdev(sb->s_bdev);
- if (sb->s_op->write_super_lockfs)
- sb->s_op->write_super_lockfs(sb);
+ if (sb->s_op->write_super_lockfs)
+ sb->s_op->write_super_lockfs(sb);
+ }
}
sync_blockdev(bdev);
-
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