The function will create lost+found directory, link the deleted
subvolume specified by the subvol_id to the directory, update the
information of root_item and cleanup the associated orphan item.
Signed-off-by: Lu Fengqi <lufq.f...@cn.fujitsu.com>
---
undelete-subvol.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 76 insertions(+)
diff --git a/undelete-subvol.c b/undelete-subvol.c
index 781057df2b84..9243e35545c5 100644
--- a/undelete-subvol.c
+++ b/undelete-subvol.c
@@ -106,3 +106,79 @@ out:
btrfs_release_path(&path);
return ret;
}
+
+/*
+ * Recover a subvolume specified by subvol_id, and link it to the lost+found
+ * directory.
+ *
+ * @root: the root of the root tree.
+ * @subvol_id: specify the subvolume which will be linked, and also be the part
+ * of the subvolume name.
+ *
+ * Return 0 if no error occurred.
+ */
+static int link_subvol_to_lostfound(struct btrfs_root *root, u64 subvol_id)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_root *fs_root = fs_info->fs_root;
+ char buf[BTRFS_NAME_LEN + 1] = {0}; /* 1 for snprintf null */
+ char *dir_name = "lost+found";
+ u64 lost_found_ino = 0;
+ u32 mode = 0700;
+ int ret;
+
+ /*
+ * For link subvolume to lost+found,
+ * 2 for parent(256)'s dir_index and dir_item
+ * 2 for lost+found dir's inode_item and inode_ref
+ * 2 for lost+found dir's dir_index and dir_item for the subvolume
+ * 2 for the subvolume's root_ref and root_backref
+ */
+ trans = btrfs_start_transaction(fs_root, 8);
+ if (IS_ERR(trans)) {
+ error("unable to start transaction");
+ ret = PTR_ERR(trans);
+ goto out;
+ }
+
+ /* Create lost+found directory */
+ ret = btrfs_mkdir(trans, fs_root, dir_name, strlen(dir_name),
+ BTRFS_FIRST_FREE_OBJECTID, &lost_found_ino,
+ mode);
+ if (ret < 0) {
+ error("failed to create '%s' dir: %d", dir_name, ret);
+ goto out;
+ }
+
+ /* Link the subvolume to lost+found directory */
+ snprintf(buf, BTRFS_NAME_LEN + 1, "sub%llu", subvol_id);
+ ret = btrfs_link_subvol(trans, fs_root, buf, subvol_id, lost_found_ino,
+ false);
+ if (ret) {
+ error("failed to link the subvol %llu: %d", subvol_id, ret);
+ goto out;
+ }
+
+ /* Clear root flags BTRFS_ROOT_SUBVOL_DEAD and increase root refs */
+ ret = recover_dead_root(trans, root, subvol_id);
+ if (ret)
+ goto out;
+
+ /* Delete the orphan item after undeletion is completed. */
+ ret = btrfs_del_orphan_item(trans, root, subvol_id);
+ if (ret) {
+ error("failed to delete the orphan_item for %llu: %d",
+ subvol_id, ret);
+ goto out;
+ }
+
+ ret = btrfs_commit_transaction(trans, fs_root);
+ if (ret) {
+ error("transaction commit failed: %d", ret);
+ goto out;
+ }
+
+out:
+ return ret;
+}
--
2.16.1
--
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