diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index a1216f9b4917..2ed36af6e43a 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -3353,6 +3353,37 @@ static int wait_for_dest_dir_move(struct send_ctx *sctx, return ret; } +/* + * Check if ino ino1 is an ancestor of inode ino2 in the given root. + * Return 1 if true, 0 if false and < 0 on error. + */ +static int is_ancestor(struct btrfs_root *root, + const u64 ino1, + const u64 ino1_gen, + const u64 ino2, + struct fs_path *fs_path) +{ + u64 ino = ino2; + + while (ino > BTRFS_FIRST_FREE_OBJECTID) { + int ret; + u64 parent; + u64 parent_gen; + + fs_path_reset(fs_path); + ret = get_first_ref(root, ino, &parent, &parent_gen, fs_path); + if (ret < 0) { + if (ret == -ENOENT && ino == ino2) + ret = 0; + return ret; + } + if (parent == ino1) + return parent_gen == ino1_gen ? 1 : 0; + ino = parent; + } + return 0; +} + static int wait_for_parent_move(struct send_ctx *sctx, struct recorded_ref *parent_ref) { @@ -3374,11 +3405,24 @@ static int wait_for_parent_move(struct send_ctx *sctx, * Our current directory inode may not yet be renamed/moved because some * ancestor (immediate or not) has to be renamed/moved first. So find if * such ancestor exists and make sure our own rename/move happens after - * that ancestor is processed. + * that ancestor is processed to avoid path build infinite loops (done + * at get_cur_path()). */ while (ino > BTRFS_FIRST_FREE_OBJECTID) { if (is_waiting_for_move(sctx, ino)) { - ret = 1; + /* + * If the current inode is an ancestor of ino in the + * parent root, we need to delay the rename of the + * current inode, otherwise don't delayed the rename + * because we can end up with a circular dependency + * of renames, resulting in some directories never + * getting the respective rename operations issued in + * the send stream or getting into infinite path build + * loops. + */ + ret = is_ancestor(sctx->parent_root, + sctx->cur_ino, sctx->cur_inode_gen, + ino, path_before); break; }