bcachefs: Fix BTREE_ITER_NOT_EXTENTS

bch2_btree_iter_peek() wasn't properly checking for
BTREE_ITER_IS_EXTENTS when updating iter->pos.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_gc.c

@@ -1243,7 +1243,7 @@ int bch2_gc_gens(struct bch_fs *c)
 	}
 
 	for (i = 0; i < BTREE_ID_NR; i++)
-		if (btree_node_type_needs_gc(i)) {
+		if ((1 << i) & BTREE_ID_HAS_PTRS) {
 			ret = bch2_gc_btree_gens(c, i);
 			if (ret) {
 				bch_err(c, "error recalculating oldest_gen: %i", ret);

fs/bcachefs/btree_iter.c

@@ -1641,7 +1641,9 @@ static inline struct bkey_s_c __btree_iter_peek(struct btree_iter *iter, bool wi
 	 * iter->pos should be mononotically increasing, and always be equal to
 	 * the key we just returned - except extents can straddle iter->pos:
 	 */
-	if (bkey_cmp(bkey_start_pos(k.k), iter->pos) > 0)
+	if (!(iter->flags & BTREE_ITER_IS_EXTENTS))
+		iter->pos = k.k->p;
+	else if (bkey_cmp(bkey_start_pos(k.k), iter->pos) > 0)
 		iter->pos = bkey_start_pos(k.k);
 
 	bch2_btree_iter_verify_entry_exit(iter);

fs/bcachefs/btree_types.h

@@ -616,6 +616,10 @@ static inline bool btree_iter_is_extents(struct btree_iter *iter)
 	 (1U << BTREE_ID_dirents)|			\
 	 (1U << BTREE_ID_xattrs))
 
+#define BTREE_ID_HAS_PTRS				\
+	((1U << BTREE_ID_extents)|			\
+	 (1U << BTREE_ID_reflink))
+
 static inline bool btree_type_has_snapshots(enum btree_id id)
 {
 	return (1 << id) & BTREE_ID_HAS_SNAPSHOTS;