Btrfs devel - Jan 2010 - [PATCH] Btrfs: fix another orphan cleanup problem

Because orphan cleanup now happens well after the fs is all initialized and
such, we can run into this problem where we find orphan entries that were just
added to the fs, not ones that were added previously during a crash.  This does
not bode well for the system, and results in a couple of odd things happening,
like truncate being run on non-regular files.  In order to fix this we just
check and see if the inode has been added to the in-memory orphan list, and if
it has, set the key to it''s inode number - 1 so we don''t find
this orphan entry
again, and continue searching.

This problem kept popping up while running xfs tests, and was 100%
reproduceable.  With this patch the problem no longer happens.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
---
 fs/btrfs/inode.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index c7fbfaa..067f4b5 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2202,6 +2202,17 @@ void btrfs_orphan_cleanup(struct btrfs_root *root)
 		 * the proper thing when we hit it
 		 */
 		spin_lock(&root->list_lock);
+		if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
+			/*
+			 * This inode is on the in-memory list, which means we
+			 * shouldn''t be cleaning it up, move on to the next
+			 * orphan item.
+			 */
+			spin_unlock(&root->list_lock);
+			key.offset = inode->i_ino - 1;
+			iput(inode);
+			continue;
+		}
 		list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
 		spin_unlock(&root->list_lock);
 
-- 
1.5.4.3

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On Tue, Jan 26, 2010 at 5:01 AM, Josef Bacik <josef@redhat.com>
wrote:
> Because orphan cleanup now happens well after the fs is all initialized and
> such, we can run into this problem where we find orphan entries that were
just
> added to the fs, not ones that were added previously during a crash.  This
does
> not bode well for the system, and results in a couple of odd things
happening,
> like truncate being run on non-regular files.  In order to fix this we just
> check and see if the inode has been added to the in-memory orphan list, and
if
> it has, set the key to it''s inode number - 1 so we don''t
find this orphan entry
> again, and continue searching.
>
> This problem kept popping up while running xfs tests, and was 100%
> reproduceable.  With this patch the problem no longer happens.  Thanks,
>
Hi Josef,

I think this problem was introduced by your previous orphan cleanup fix.
Before I introduced the orphan cleanup regression, orphan cleanup on
a subvol was triggered by the first access. Your previous orphan clean fix
broke this rule, orphan clean is triggered when the first time btrfs_lookup
finds a valid inode. I think it''s better to keep the old rule. revert
your
previous changes and add code to open_ctree() to do orphan cleanup for
the default subvol.

Regards
Yan, Zheng
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