bcachefs: Don't allow bkey vals that are too big in extents btree

Make sure we don't overflow BKEY_PADDED keys
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/bkey_methods.c

@@ -82,6 +82,11 @@ const char *__bch2_bkey_invalid(struct bch_fs *c, struct bkey_s_c k,
 	if (k.k->u64s < BKEY_U64s)
 		return "u64s too small";
 
+	if ((btree_node_type_is_extents(type) ||
+	     type == BKEY_TYPE_BTREE) &&
+	    bkey_val_u64s(k.k) > BKEY_EXTENT_VAL_U64s_MAX)
+		return "value too big";
+
 	if (btree_node_type_is_extents(type)) {
 		if ((k.k->size == 0) != bkey_deleted(k.k))
 			return "bad size field";

fs/bcachefs/extents.c

@@ -1291,9 +1291,6 @@ void bch2_insert_fixup_extent(struct btree_trans *trans,
 
 const char *bch2_extent_invalid(const struct bch_fs *c, struct bkey_s_c k)
 {
-	if (bkey_val_u64s(k.k) > BKEY_EXTENT_VAL_U64s_MAX)
-		return "value too big";
-
 	return bch2_bkey_ptrs_invalid(c, k);
 }