bcachefs: Correctly validate k->u64s in btree node read path

validate_bset_keys() never properly validated k->u64s; it checked if it
was 0, but not if it was smaller than keys for the given packed format;
this fixes that small oversight.

This patch was backported, so it's adding quite a few error enums so
that they don't get renumbered and we don't have confusing gaps.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/bkey.h

@@ -362,10 +362,7 @@ static inline struct bpos bkey_start_pos(const struct bkey *k)
 static inline unsigned bkeyp_key_u64s(const struct bkey_format *format,
 				      const struct bkey_packed *k)
 {
-	unsigned ret = bkey_packed(k) ? format->key_u64s : BKEY_U64s;
-
-	EBUG_ON(k->u64s < ret);
-	return ret;
+	return bkey_packed(k) ? format->key_u64s : BKEY_U64s;
 }
 
 static inline unsigned bkeyp_key_bytes(const struct bkey_format *format,

fs/bcachefs/btree_io.c

@@ -840,6 +840,9 @@ static bool __bkey_valid(struct bch_fs *c, struct btree *b,
 	if (k->format > KEY_FORMAT_CURRENT)
 		return false;
 
+	if (k->u64s < bkeyp_key_u64s(&b->format, k))
+		return false;
+
 	struct printbuf buf = PRINTBUF;
 	struct bkey tmp;
 	struct bkey_s u = __bkey_disassemble(b, k, &tmp);
@@ -881,7 +884,13 @@ static int validate_bset_keys(struct bch_fs *c, struct btree *b,
 				 "invalid bkey format %u", k->format))
 			goto drop_this_key;
 
-		/* XXX: validate k->u64s */
+		if (btree_err_on(k->u64s < bkeyp_key_u64s(&b->format, k),
+				 -BCH_ERR_btree_node_read_err_fixable,
+				 c, NULL, b, i,
+				 btree_node_bkey_bad_u64s,
+				 "k->u64s too small (%u < %u)", k->u64s, bkeyp_key_u64s(&b->format, k)))
+			goto drop_this_key;
+
 		if (!write)
 			bch2_bkey_compat(b->c.level, b->c.btree_id, version,
 				    BSET_BIG_ENDIAN(i), write,

fs/bcachefs/sb-errors_types.h

@@ -250,7 +250,22 @@
 	x(hash_table_key_duplicate,				242)	\
 	x(hash_table_key_wrong_offset,				243)	\
 	x(unlinked_inode_not_on_deleted_list,			244)	\
-	x(reflink_p_front_pad_bad,				245)
+	x(reflink_p_front_pad_bad,				245)	\
+	x(journal_entry_dup_same_device,			246)	\
+	x(inode_bi_subvol_missing,				247)	\
+	x(inode_bi_subvol_wrong,				248)	\
+	x(inode_points_to_missing_dirent,			249)	\
+	x(inode_points_to_wrong_dirent,				250)	\
+	x(inode_bi_parent_nonzero,				251)	\
+	x(dirent_to_missing_parent_subvol,			252)	\
+	x(dirent_not_visible_in_parent_subvol,			253)	\
+	x(subvol_fs_path_parent_wrong,				254)	\
+	x(subvol_root_fs_path_parent_nonzero,			255)	\
+	x(subvol_children_not_set,				256)	\
+	x(subvol_children_bad,					257)	\
+	x(subvol_loop,						258)	\
+	x(subvol_unreachable,					259)	\
+	x(btree_node_bkey_bad_u64s,				260)
 
 enum bch_sb_error_id {
 #define x(t, n) BCH_FSCK_ERR_##t = n,