[PATCH 1/2] xfs: assert that xattr inactivation never reaches a hole

[Brian Foster <bfoster@redhat.com>]

The child buffer read in xfs_attr3_node_inactive() should never
reach a hole in the attr fork. If this occurs, it is likely due to a
bug. Prior to commit cd87d867 ("xfs: don't crash on unexpected holes
in dir/attr btrees"), this would result in a crash. Now that the
crash has been fixed, this is a silent failure.

Add an assert in this codepath to detect this particular condition.
Note that the right fix here may be to pass -1 to
xfs_da3_node_read() such that a hole returns an error. This is a
cautious first step in that direction.

Signed-off-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/xfs_attr_inactive.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/xfs/xfs_attr_inactive.c b/fs/xfs/xfs_attr_inactive.c
index ebd66b1..6b4f5c6 100644
--- a/fs/xfs/xfs_attr_inactive.c
+++ b/fs/xfs/xfs_attr_inactive.c
@@ -255,6 +255,7 @@ xfs_attr3_node_inactive(
 						XFS_ATTR_FORK);
 		if (error)
 			return error;
+		ASSERT(child_bp);
 		if (child_bp) {
 						/* save for re-read later */
 			child_blkno = XFS_BUF_ADDR(child_bp);
-- 
2.9.5