[2/2] Btrfs: fix copy_items() return value when logging an inode

Commit Message

Filipe Manana March 26, 2018, 10:59 p.m. UTC

From: Filipe Manana <[e-mail]>

When logging an inode, at tree-log.c:copy_items(), if we call
btrfs_next_leaf() at the loop which checks for the need to log holes, we
need to make sure copy_items() returns the value 1 to its caller and
not 0 (on success). This is because the path the caller passed was
released and is now different from what is was before, and the caller
expects a return value of 0 to mean both success and that the path
has not changed, while a return value of 1 means both success and
signals the caller that it can not reuse the path, it has to perform
another tree search.

Even though this is a case that should not be triggered on normal
circumstances or very rare at least, its consequences can be very
unpredictable (especially when replaying a log tree).

Fixes: 16e7549f045d ("Btrfs: incompatible format change to remove hole extents")
Signed-off-by: Filipe Manana <[e-mail]>
---
 fs/btrfs/tree-log.c | 1 +
 1 file changed, 1 insertion(+)

Patch

diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 1d738ff5c41b..abd9fd81cd1c 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3960,6 +3960,7 @@  static noinline int copy_items(struct btrfs_trans_handle *trans,
 			ASSERT(ret == 0);
 			src = src_path->nodes[0];
 			i = 0;
+			need_find_last_extent = true;
 		}
 
 		btrfs_item_key_to_cpu(src, &key, i);