bcachefs: Fix a btree iter bug when iter pos == POS_MAX

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

diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
index 1ab468a29d21a6202e2517097e6f2f3cc4bee718..1ba59c53c36fbb1bd78b4c9ccab94195088cbabf 100644 (file)
--- a/fs/bcachefs/btree_iter.c
+++ b/fs/bcachefs/btree_iter.c
@@ -36,7 +36,16 @@ static inline int __btree_iter_pos_cmp(struct btree_iter *iter,
                return cmp;
        if (bkey_deleted(k))
                return -1;
-       if (iter->flags & BTREE_ITER_IS_EXTENTS)
+
+       /*
+        * Normally, for extents we want the first key strictly greater than
+        * the iterator position - with the exception that for interior nodes,
+        * we don't want to advance past the last key if the iterator position
+        * is POS_MAX:
+        */
+       if (iter->flags & BTREE_ITER_IS_EXTENTS &&
+           (!interior_node ||
+            bkey_cmp_left_packed_byval(b, k, POS_MAX)))
                return -1;
        return 1;
 }
@@ -691,8 +700,7 @@ static inline bool btree_iter_pos_after_node(struct btree_iter *iter,
                                             struct btree *b)
 {
        return __btree_iter_pos_cmp(iter, NULL,
-                       bkey_to_packed(&b->key), true) < 0 &&
-               bkey_cmp(b->key.k.p, POS_MAX);
+                       bkey_to_packed(&b->key), true) < 0;
 }
 
 static inline bool btree_iter_pos_in_node(struct btree_iter *iter,