Btrfs-progs: repair missing dir index

If we have an inode backref entry then we know enough to add back a missing dir
index.  When messing with the inode backrefs we need to do all of that first
before we process the inode recs themselves as we may clear errors on the inode
recs as we fix the directory indexes.  This adds the framework for fixing
backref errors and fixes missing dir index issues.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.cz>

1 files changed, 119 insertions, 2 deletions

diff --git a/cmds-check.c b/cmds-check.c
index f6fde23..d866411 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -1583,15 +1583,111 @@ static int repair_inode_orphan_item(struct btrfs_trans_handle *trans,
 	return ret;
 }
 
+static int add_missing_dir_index(struct btrfs_root *root,
+				 struct cache_tree *inode_cache,
+				 struct inode_record *rec,
+				 struct inode_backref *backref)
+{
+	struct btrfs_path *path;
+	struct btrfs_trans_handle *trans;
+	struct btrfs_dir_item *dir_item;
+	struct extent_buffer *leaf;
+	struct btrfs_key key;
+	struct btrfs_disk_key disk_key;
+	struct inode_record *dir_rec;
+	unsigned long name_ptr;
+	u32 data_size = sizeof(*dir_item) + backref->namelen;
+	int ret;
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return -ENOMEM;
+
+	trans = btrfs_start_transaction(root, 1);
+	if (IS_ERR(trans)) {
+		btrfs_free_path(path);
+		return PTR_ERR(trans);
+	}
+
+	fprintf(stderr, "repairing missing dir index item for inode %llu\n",
+		(unsigned long long)rec->ino);
+	key.objectid = backref->dir;
+	key.type = BTRFS_DIR_INDEX_KEY;
+	key.offset = backref->index;
+
+	ret = btrfs_insert_empty_item(trans, root, path, &key, data_size);
+	BUG_ON(ret);
+
+	leaf = path->nodes[0];
+	dir_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dir_item);
+
+	disk_key.objectid = cpu_to_le64(rec->ino);
+	disk_key.type = BTRFS_INODE_ITEM_KEY;
+	disk_key.offset = 0;
+
+	btrfs_set_dir_item_key(leaf, dir_item, &disk_key);
+	btrfs_set_dir_type(leaf, dir_item, imode_to_type(rec->imode));
+	btrfs_set_dir_data_len(leaf, dir_item, 0);
+	btrfs_set_dir_name_len(leaf, dir_item, backref->namelen);
+	name_ptr = (unsigned long)(dir_item + 1);
+	write_extent_buffer(leaf, backref->name, name_ptr, backref->namelen);
+	btrfs_mark_buffer_dirty(leaf);
+	btrfs_free_path(path);
+	btrfs_commit_transaction(trans, root);
+
+	backref->found_dir_index = 1;
+	dir_rec = get_inode_rec(inode_cache, backref->dir, 0);
+	if (!dir_rec)
+		return 0;
+	dir_rec->found_size += backref->namelen;
+	if (dir_rec->found_size == dir_rec->isize &&
+	    (dir_rec->errors & I_ERR_DIR_ISIZE_WRONG))
+		dir_rec->errors &= ~I_ERR_DIR_ISIZE_WRONG;
+	if (dir_rec->found_size != dir_rec->isize)
+		dir_rec->errors |= I_ERR_DIR_ISIZE_WRONG;
+
+	return 0;
+}
+
+static int repair_inode_backrefs(struct btrfs_root *root,
+				 struct inode_record *rec,
+				 struct cache_tree *inode_cache)
+{
+	struct inode_backref *tmp, *backref;
+	u64 root_dirid = btrfs_root_dirid(&root->root_item);
+	int ret = 0;
+
+	list_for_each_entry_safe(backref, tmp, &rec->backrefs, list) {
+		/* Index 0 for root dir's are special, don't mess with it */
+		if (rec->ino == root_dirid && backref->index == 0)
+			continue;
+
+		if (!backref->found_dir_index && backref->found_inode_ref) {
+			ret = add_missing_dir_index(root, inode_cache, rec,
+						    backref);
+			if (ret)
+				break;
+		}
+
+		if (backref->found_dir_item && backref->found_dir_index) {
+			if (!backref->errors && backref->found_inode_ref) {
+				list_del(&backref->list);
+				free(backref);
+			}
+		}
+	}
+
+	return ret;
+}
+
 static int try_repair_inode(struct btrfs_root *root, struct inode_record *rec)
 {
 	struct btrfs_trans_handle *trans;
 	struct btrfs_path *path;
 	int ret = 0;
 
-	/* So far we just fix dir isize wrong */
 	if (!(rec->errors & (I_ERR_DIR_ISIZE_WRONG | I_ERR_NO_ORPHAN_ITEM)))
-		return 1;
+		return rec->errors;
 
 	path = btrfs_alloc_path();
 	if (!path)
@@ -1629,6 +1725,27 @@ static int check_inode_recs(struct btrfs_root *root,
 		return 0;
 	}
 
+	/*
+	 * We need to repair backrefs first because we could change some of the
+	 * errors in the inode recs.
+	 *
+	 * For example, if we were missing a dir index then the directories
+	 * isize would be wrong, so if we fixed the isize to what we thought it
+	 * would be and then fixed the backref we'd still have a invalid fs, so
+	 * we need to add back the dir index and then check to see if the isize
+	 * is still wrong.
+	 */
+	cache = search_cache_extent(inode_cache, 0);
+	while (repair && cache) {
+		node = container_of(cache, struct ptr_node, cache);
+		rec = node->data;
+		cache = next_cache_extent(cache);
+
+		if (list_empty(&rec->backrefs))
+			continue;
+		repair_inode_backrefs(root, rec, inode_cache);
+	}
+
 	rec = get_inode_rec(inode_cache, root_dirid, 0);
 	if (rec) {
 		ret = check_root_dir(rec);