Historically, we required that all btree node roots point to a valid (possibly fake) node, but we're improving our ability to continue in the presence of errors.
Reported-by: [email protected] Signed-off-by: Kent Overstreet <[email protected]> --- fs/bcachefs/btree_iter.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c index 89f9665ce70d..80c3b55ce763 100644 --- a/fs/bcachefs/btree_iter.c +++ b/fs/bcachefs/btree_iter.c @@ -722,7 +722,7 @@ static inline int btree_path_lock_root(struct btree_trans *trans, unsigned long trace_ip) { struct bch_fs *c = trans->c; - struct btree *b, **rootp = &bch2_btree_id_root(c, path->btree_id)->b; + struct btree_root *r = bch2_btree_id_root(c, path->btree_id); enum six_lock_type lock_type; unsigned i; int ret; @@ -730,7 +730,12 @@ static inline int btree_path_lock_root(struct btree_trans *trans, EBUG_ON(path->nodes_locked); while (1) { - b = READ_ONCE(*rootp); + struct btree *b = READ_ONCE(r->b); + if (unlikely(!b)) { + BUG_ON(!r->error); + return r->error; + } + path->level = READ_ONCE(b->c.level); if (unlikely(path->level < depth_want)) { @@ -755,7 +760,7 @@ static inline int btree_path_lock_root(struct btree_trans *trans, BUG(); } - if (likely(b == READ_ONCE(*rootp) && + if (likely(b == READ_ONCE(r->b) && b->c.level == path->level && !race_fault())) { for (i = 0; i < path->level; i++) -- 2.45.2
