[PATCH] btrfs: Improve error reporting in lookup_inline_extent_backref

[Nikolay Borisov <nborisov@suse.com>]

When iterating the backrefs in an extent item if the ptr to the
'current' backref record goes beyond the extent item a warning is
generated and -ENOENT is returned. However what's more appropriate to
debug such cases would be to return EUCLEAN and also print the in-memory
state of the offending leaf.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/extent-tree.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 963160a0c393..5a53bcfdca83 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -895,7 +895,10 @@ int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
 	err = -ENOENT;
 	while (1) {
 		if (ptr >= end) {
-			WARN_ON(ptr > end);
+			if (WARN_ON(ptr > end)) {
+				err = -EUCLEAN;
+				btrfs_print_leaf(path->slots[0]);
+			}
 			break;
 		}
 		iref = (struct btrfs_extent_inline_ref *)ptr;
-- 
2.25.1