Btrfs devel - Feb 2013 - [PATCH] Btrfs: account for orphan inodes properly during cleanup

Dave sent me a panic where we were doing the orphan cleanup and
panic''ed
trying to release our reservation from the orphan block rsv.  The reason for
this is because our orphan block rsv had been free''d out from
underneath us
because the transaction commit found that there were no orphan inodes
according to its count and decided to free it.  This is incorrect so make
sure we inc the orphan inodes count so the accounting is all done properly.
This would also cause the warning in the orphan commit code normally if you
had any orphans to cleanup as they would only decrement the orphan count so
you''d get a negative orphan count which could cause problems during
runtime.
Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
---
 fs/btrfs/inode.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 804a34b..5398883 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2502,6 +2502,7 @@ int btrfs_orphan_cleanup(struct btrfs_root *root)
 		 */
 		set_bit(BTRFS_INODE_HAS_ORPHAN_ITEM,
 			&BTRFS_I(inode)->runtime_flags);
+		atomic_inc(&root->orphan_inodes);
 
 		/* if we have links, this was a truncate, lets do that */
 		if (inode->i_nlink) {
-- 
1.7.7.6

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On Fri, Feb 01, 2013 at 04:05:17PM -0500, Josef Bacik
wrote:
> Dave sent me a panic where we were doing the orphan cleanup and
panic''ed
> trying to release our reservation from the orphan block rsv.  The reason
for
> this is because our orphan block rsv had been free''d out from
underneath us
> because the transaction commit found that there were no orphan inodes
> according to its count and decided to free it.  This is incorrect so make
> sure we inc the orphan inodes count so the accounting is all done properly.
> This would also cause the warning in the orphan commit code normally if you
> had any orphans to cleanup as they would only decrement the orphan count so
> you''d get a negative orphan count which could cause problems
during runtime.
> Thanks,
Thanks. I''ve tried to reproduce it with an unpatched kernel, but was
unsuccesful (the same test was running for 3 days) and can''t reliably
verify your fix. Looks like a very tiny race.

david
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