From patchwork Tue Jun 23 10:39:47 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: robbieko X-Patchwork-Id: 6659551 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id C61119F39B for ; Tue, 23 Jun 2015 10:44:09 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D5F4D20645 for ; Tue, 23 Jun 2015 10:44:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA7C12063F for ; Tue, 23 Jun 2015 10:44:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754579AbbFWKmg (ORCPT ); Tue, 23 Jun 2015 06:42:36 -0400 Received: from mail.synology.com ([59.124.41.242]:5902 "EHLO mail.synology.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754528AbbFWKkB (ORCPT ); Tue, 23 Jun 2015 06:40:01 -0400 Received: from localhost.localdomain (unknown [192.168.0.216]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: robbieko@synology.com) by mail.synology.com (Postfix) with ESMTPSA id D8E7F2B31839; Tue, 23 Jun 2015 18:39:56 +0800 (CST) From: Robbie Ko To: linux-btrfs@vger.kernel.org Cc: Robbie Ko Subject: [PATCH v3 3/7] Btrfs: incremental send, avoid ancestor rename to descendant Date: Tue, 23 Jun 2015 18:39:47 +0800 Message-Id: <1435055991-10109-4-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> X-MailScanner-ID: D8E7F2B31839.A9AFC X-MailScanner: Found to be clean X-MailScanner-SpamCheck: not spam (whitelisted), SpamAssassin (cached, score=1.059, required 8, ALL_TRUSTED -1.00, AWL 2.56, BAYES_05 -0.50, URIBL_BLOCKED 0.00) X-MailScanner-From: robbieko@synology.com X-Spam-Status: No, score=-8.3 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP There's one more case where we can't issue a rename operation for a directory as soon as we process it. We move a directory from ancestor to descendant. |---- a |---- b |---- c |---- d "Move a directory from ancestor to descendant" means moving dir. a into dir. c This case will happen after applying "[PATCH] Btrfs: incremental send, don't delay directory renames unnecessarily". Because, that patch changes behavior of wait_for_parent_move function. 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) 1. 259 must move to @tmp/other_dir, so it is waiting on other_dir(264). 2. 260 is able to rename as ance/wait_at_below_ance/pre since wait_at_below_ance(259) is waiting and 260 is not the ancestor of wait_at_below_ance(259). 3. 261 must move to @tmp/other_dir, so it is waiting on other_dir(264). 4. 262 is able to rename as ance/wait_at_below_ance/pre/wait_dir/desc since wait_dir(261) is waiting and 262 is not the ancestor of wait_dir(261). 5. 263 is rename as ance/wait_at_below_ance/pre/wait_dir/desc/ance since wait_dir(261) is waiting and 263 is not the ancestor of wait_dir(261). At the same time, receiving side will encounter error. If anyone calls get_cur_path() to any element in ance/wait_at_below_ance/pre/wait_dir/desc/ance like wait_dir(260), there will cause path building loop like this : 261 -> 260 -> 259 -> 263 -> 262 -> 261 So fix the problem by check path_loop for this case. Signed-off-by: Robbie Ko --- V3: add error handling and modify comment and coding style fs/btrfs/send.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 48 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index 95dc1d4..ca8cb87 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -3089,13 +3089,18 @@ static int path_loop(struct send_ctx *sctx, struct fs_path *name, *ancestor_ino = 0; while (ino != BTRFS_FIRST_FREE_OBJECTID) { + struct waiting_dir_move *wdm; fs_path_reset(name); if (is_waiting_for_rm(sctx, ino)) break; - if (is_waiting_for_move(sctx, ino)) { + + wdm = get_waiting_dir_move(sctx, ino); + if (wdm) { if (*ancestor_ino == 0) *ancestor_ino = ino; + if (wdm->orphanized) + break; ret = get_first_ref(sctx->parent_root, ino, &parent_inode, &parent_gen, name); } else { @@ -3748,6 +3753,48 @@ verbose_printk("btrfs: process_recorded_refs %llu\n", sctx->cur_ino); } /* + * need to check whether rename/move causes path loop. + * If it does, need to delay the rename of the current + * inode (sctx->cur_ino), then perform after the rename of + * its ancestor. + */ + if (S_ISDIR(sctx->cur_inode_mode) && + sctx->parent_root && can_rename) { + struct fs_path *name = NULL; + u64 ancestor; + u64 old_send_progress = sctx->send_progress; + + name = fs_path_alloc(); + if (!name) { + ret = -ENOMEM; + goto out; + } + + sctx->send_progress = sctx->cur_ino + 1; + ret = path_loop(sctx, name, sctx->cur_ino, + sctx->cur_inode_gen, &ancestor); + if (ret) { + ret = add_pending_dir_move(sctx, sctx->cur_ino, + sctx->cur_inode_gen, + ancestor, + &sctx->new_refs, + &sctx->deleted_refs, + is_orphan); + if (ret < 0) { + sctx->send_progress = old_send_progress; + fs_path_free(name); + goto out; + } + can_rename = false; + *pending_move = 1; + } + sctx->send_progress = old_send_progress; + fs_path_free(name); + if (ret < 0) + goto out; + } + + /* * link/move the ref to the new place. If we have an orphan * inode, move it and update valid_path. If not, link or move * it depending on the inode mode.