From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.synology.com ([59.124.41.242]:23565 "EHLO mail.synology.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754285AbbFWKkA (ORCPT ); Tue, 23 Jun 2015 06:40:00 -0400 From: Robbie Ko To: linux-btrfs@vger.kernel.org Cc: Robbie Ko Subject: [PATCH v3 1/7] Revert "Btrfs: incremental send, remove dead code" Date: Tue, 23 Jun 2015 18:39:45 +0800 Message-Id: <1435055991-10109-2-git-send-email-robbieko@synology.com> In-Reply-To: <1435055991-10109-1-git-send-email-robbieko@synology.com> References: <1435055991-10109-1-git-send-email-robbieko@synology.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: This reverts commit 5f806c3ae2ff6263a10a6901f97abb74dac03d36. This is a necessary patch for a subsequent patch in the series (patch 3). "[PATCH] Btrfs: incremental send, don't delay directory renames unnecessarily" changes behavior of wait_for_parent_move function. It may cause path loop problem, so fix it in the patch 3. Example: Parent snapshot: |---- @tmp/ (ino 257) |---- pre/ (ino 260) |---- wait_dir (ino 261) |---- ance/ (ino 263) |---- wait_at_below_ance/ (ino 259) |---- desc/ (ino 262) |---- other_dir/ (ino 264) Send snapshot: |---- @tmp/ (ino 257) |---- other_dir/ (ino 264) |---- wait_at_below_ance/ (ino 259) |---- pre/ (ino 260) |---- wait_dir/ (ino 261) |---- desc/ (ino 262) |---- ance/ (ino 263) This cause will cause path building loop like this : 261 -> 260 -> 259 -> 263 -> 262 -> 261 Signed-off-by: Robbie Ko --- V3: modify comment fs/btrfs/send.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index 1c1f161..257753b 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -3080,6 +3080,48 @@ static struct pending_dir_move *get_pending_dir_moves(struct send_ctx *sctx, return NULL; } +static int path_loop(struct send_ctx *sctx, struct fs_path *name, + u64 ino, u64 gen, u64 *ancestor_ino) +{ + int ret = 0; + u64 parent_inode = 0; + u64 parent_gen = 0; + u64 start_ino = ino; + + *ancestor_ino = 0; + while (ino != BTRFS_FIRST_FREE_OBJECTID) { + fs_path_reset(name); + + if (is_waiting_for_rm(sctx, ino)) + break; + if (is_waiting_for_move(sctx, ino)) { + if (*ancestor_ino == 0) + *ancestor_ino = ino; + ret = get_first_ref(sctx->parent_root, ino, + &parent_inode, &parent_gen, name); + } else { + ret = __get_cur_name_and_parent(sctx, ino, gen, + &parent_inode, + &parent_gen, name); + if (ret > 0) { + ret = 0; + break; + } + } + if (ret < 0) + break; + if (parent_inode == start_ino) { + ret = 1; + if (*ancestor_ino == 0) + *ancestor_ino = ino; + break; + } + ino = parent_inode; + gen = parent_gen; + } + return ret; +} + static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm) { struct fs_path *from_path = NULL; @@ -3091,6 +3133,7 @@ static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm) struct waiting_dir_move *dm = NULL; u64 rmdir_ino = 0; int ret; + u64 ancestor = 0; name = fs_path_alloc(); from_path = fs_path_alloc(); @@ -3122,6 +3165,22 @@ static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm) goto out; sctx->send_progress = sctx->cur_ino + 1; + ret = path_loop(sctx, name, pm->ino, pm->gen, &ancestor); + if (ret) { + LIST_HEAD(deleted_refs); + ASSERT(ancestor > BTRFS_FIRST_FREE_OBJECTID); + ret = add_pending_dir_move(sctx, pm->ino, pm->gen, ancestor, + &pm->update_refs, &deleted_refs, + pm->is_orphan); + if (ret < 0) + goto out; + if (rmdir_ino) { + dm = get_waiting_dir_move(sctx, pm->ino); + ASSERT(dm); + dm->rmdir_ino = rmdir_ino; + } + goto out; + } fs_path_reset(name); to_path = name; name = NULL; -- 1.9.1