btrfs-progs: check: properly fix missing INODE_REF cases

check/main.c

@@ -87,6 +87,7 @@ bool is_free_space_tree = false;
 bool init_extent_tree = false;
 bool check_data_csum = false;
 static bool found_free_ino_cache = false;
+static bool found_unknown_key = false;
 struct cache_tree *roots_info_cache = NULL;
 
 enum btrfs_check_mode {
@@ -1895,6 +1896,10 @@ static int process_one_leaf(struct btrfs_root *root, struct extent_buffer *eb,
 ret = process_xattr_item(eb, i, &key, active_node);
 break;
 default:
+error("Unknown key (%llu %u %llu) found in leaf %llu",
+ key.objectid, key.type, key.offset,
+ eb->start);
+found_unknown_key = true;
 break;
 };
 }
@@ -2346,6 +2351,42 @@ static int create_inode_item(struct btrfs_root *root,
 return 0;
 }
 
+static int create_inode_ref(struct btrfs_root *root,
+ struct inode_record *i_rec,
+ struct inode_backref *backref)
+{
+struct btrfs_trans_handle *trans;
+int ret;
+
+trans = btrfs_start_transaction(root, 1);
+if (IS_ERR(trans)) {
+ret = PTR_ERR(trans);
+errno = -ret;
+error_msg(ERROR_MSG_START_TRANS, "%m");
+return ret;
+}
+
+ret = btrfs_insert_inode_ref(trans, root, backref->name, backref->namelen,
+ i_rec->ino, backref->dir, backref->index);
+if (ret < 0) {
+btrfs_commit_transaction(trans, root);
+return ret;
+}
+ret = btrfs_commit_transaction(trans, root);
+if (ret < 0) {
+ret = PTR_ERR(trans);
+errno = -ret;
+error_msg(ERROR_MSG_COMMIT_TRANS, "%m");
+return ret;
+}
+backref->found_inode_ref = 1;
+backref->errors &= ~REF_ERR_NO_INODE_REF;
+printf("Added INODE_REF for root %lld ino %llu parent %llu index %llu name %.*s\n",
+btrfs_root_id(root), i_rec->ino, backref->dir, backref->index,
+backref->namelen, backref->name);
+return 0;
+}
+
 static int repair_inode_backrefs(struct btrfs_root *root,
  struct inode_record *rec,
  struct cache_tree *inode_cache,
@@ -2370,6 +2411,21 @@ static int repair_inode_backrefs(struct btrfs_root *root,
 if (rec->ino == root_dirid && backref->index == 0)
 continue;
 
+/*
+ * Have DIR_INDEX, DIR_ITEM and INODE_ITEM, and even nlinks
+ * matches with only missing INODE_REF.
+ */
+if (!backref->found_inode_ref && backref->found_dir_item &&
+ backref->found_dir_index && rec->found_inode_item &&
+ rec->found_link == rec->nlink) {
+ret = create_inode_ref(root, rec, backref);
+if (ret)
+break;
+repaired++;
+list_del(&backref->list);
+free(backref);
+continue;
+}
 if (delete &&
  ((backref->found_dir_index && !backref->found_inode_ref) ||
  (backref->found_dir_index && backref->found_inode_ref &&
@@ -4027,6 +4083,8 @@ static int check_fs_roots(struct cache_tree *root_cache)
 free_extent_cache_tree(&wc.shared);
 if (!cache_tree_empty(&wc.shared))
 fprintf(stderr, "warning line %d\n", __LINE__);
+if (!err && found_unknown_key)
+err = 1;
 
 return err;
 }

check/mode-lowmem.c

@@ -1015,6 +1015,17 @@ static int repair_ternary_lowmem(struct btrfs_root *root, u64 dir_ino, u64 ino,
 int stage = 0;
 int ret = 0;
 
+/*
+ * We miss an INODE_REF, and we're checking DIR_ITEM and hasn't yet
+ * find the DIR_INDEX, thus there is no reliable index.
+ * Try to locate one, this can be slow as we need to locate the DIR_INDEX
+ * item from the directory.
+ */
+if (index == (u64)-1 && (err & INODE_REF_MISSING)) {
+ret = find_dir_index(root, dir_ino, ino, &index, name, name_len, filetype);
+if (ret < 0)
+err |= DIR_INDEX_MISSING;
+}
 /*
  * stage shall be one of following valild values:
  *	0: Fine, nothing to do.
@@ -2808,8 +2819,9 @@ static int check_inode_item(struct btrfs_root *root, struct btrfs_path *path)
 case BTRFS_XATTR_ITEM_KEY:
 break;
 default:
-error("ITEM[%llu %u %llu] UNKNOWN TYPE",
- key.objectid, key.type, key.offset);
+error("ITEM[%llu %u %llu] UNKNOWN TYPE in leaf %llu",
+ key.objectid, key.type, key.offset, node->start);
+err |= UNKNOWN_KEY;
 }
 }
 

check/mode-lowmem.h

@@ -48,6 +48,7 @@
 #define INVALID_GENERATION	(1U << 26)	/* Generation is too new */
 #define SUPER_BYTES_USED_ERROR	(1U << 27)	/* Super bytes_used is invalid */
 #define DUP_FILENAME_ERROR	(1U << 28)	/* DIR_ITEM contains duplicate names */
+#define UNKNOWN_KEY	(1U << 29)	/* Found unknown key type in fs trees */
 
 /*
  * Error bit for low memory mode check.

tests/fsck-tests/069-unknown-fs-tree-key/test.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+#
+# Verify that check can report unknown key types in subvolume trees
+
+source "$TEST_TOP/common" || exit
+
+check_prereq btrfs
+
+check_image() {
+run_mustfail "unknown keys in subvolume trees not reported as error" \
+"$TOP/btrfs" check "$1"
+}
+
+check_all_images