bcachefs: Fix bch2_btree_path_up_until_good_node()

There was a rare bug when path->locks_want was nonzero, but not
BTREE_MAX_DEPTH, where we'd return on a valid node that wasn't locked -
oops.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
index 67a1e0d70ed92542b7ab22114f9a386435d5e8d1..7ea29724985067281bdeb81cae6a27f1348b1f4d 100644 (file)
--- a/fs/bcachefs/btree_iter.c
+++ b/fs/bcachefs/btree_iter.c
@@ -1030,7 +1030,7 @@ static inline unsigned btree_path_up_until_good_node(struct btree_trans *trans,
                                                     int check_pos)
 {
        unsigned i, l = path->level;
-
+again:
        while (btree_path_node(path, l) &&
               !btree_path_good_node(trans, path, l, check_pos))
                __btree_path_set_level_up(trans, path, l++);
@@ -1039,9 +1039,11 @@ static inline unsigned btree_path_up_until_good_node(struct btree_trans *trans,
        for (i = l + 1;
             i < path->locks_want && btree_path_node(path, i);
             i++)
-               if (!bch2_btree_node_relock(trans, path, i))
+               if (!bch2_btree_node_relock(trans, path, i)) {
                        while (l <= i)
                                __btree_path_set_level_up(trans, path, l++);
+                       goto again;
+               }
 
        return l;
 }