From patchwork Thu Jun 14 06:04:53 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 10463349 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 922D6601F9 for ; Thu, 14 Jun 2018 06:05:01 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 82DE628AD1 for ; Thu, 14 Jun 2018 06:05:01 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 75DC928AAB; Thu, 14 Jun 2018 06:05:01 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EBF6828A96 for ; Thu, 14 Jun 2018 06:05:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754672AbeFNGE6 (ORCPT ); Thu, 14 Jun 2018 02:04:58 -0400 Received: from mx2.suse.de ([195.135.220.15]:37656 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752689AbeFNGE5 (ORCPT ); Thu, 14 Jun 2018 02:04:57 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext-too.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id C06CEAC98 for ; Thu, 14 Jun 2018 06:04:55 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Subject: [PATCH] btrfs: Don't remove block group still has pinned down bytes Date: Thu, 14 Jun 2018 14:04:53 +0800 Message-Id: <20180614060453.3523-1-wqu@suse.com> X-Mailer: git-send-email 2.17.1 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP [BUG] Under certain KVM load and LTP tests, we are possible to hit the following calltrace if quota is enabled: ------ BTRFS critical (device vda2): unable to find logical 8820195328 length 4096 BTRFS critical (device vda2): unable to find logical 8820195328 length 4096 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 49 at ../block/blk-core.c:172 blk_status_to_errno+0x1a/0x30 CPU: 0 PID: 49 Comm: kworker/u2:1 Not tainted 4.12.14-15-default #1 SLE15 (unreleased) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 Workqueue: btrfs-endio-write btrfs_endio_write_helper [btrfs] task: ffff9f827b340bc0 task.stack: ffffb4f8c0304000 RIP: 0010:blk_status_to_errno+0x1a/0x30 Call Trace: submit_extent_page+0x191/0x270 [btrfs] ? btrfs_create_repair_bio+0x130/0x130 [btrfs] __do_readpage+0x2d2/0x810 [btrfs] ? btrfs_create_repair_bio+0x130/0x130 [btrfs] ? run_one_async_done+0xc0/0xc0 [btrfs] __extent_read_full_page+0xe7/0x100 [btrfs] ? run_one_async_done+0xc0/0xc0 [btrfs] read_extent_buffer_pages+0x1ab/0x2d0 [btrfs] ? run_one_async_done+0xc0/0xc0 [btrfs] btree_read_extent_buffer_pages+0x94/0xf0 [btrfs] read_tree_block+0x31/0x60 [btrfs] read_block_for_search.isra.35+0xf0/0x2e0 [btrfs] btrfs_search_slot+0x46b/0xa00 [btrfs] ? kmem_cache_alloc+0x1a8/0x510 ? btrfs_get_token_32+0x5b/0x120 [btrfs] find_parent_nodes+0x11d/0xeb0 [btrfs] ? leaf_space_used+0xb8/0xd0 [btrfs] ? btrfs_leaf_free_space+0x49/0x90 [btrfs] ? btrfs_find_all_roots_safe+0x93/0x100 [btrfs] btrfs_find_all_roots_safe+0x93/0x100 [btrfs] btrfs_find_all_roots+0x45/0x60 [btrfs] btrfs_qgroup_trace_extent_post+0x20/0x40 [btrfs] btrfs_add_delayed_data_ref+0x1a3/0x1d0 [btrfs] btrfs_alloc_reserved_file_extent+0x38/0x40 [btrfs] insert_reserved_file_extent.constprop.71+0x289/0x2e0 [btrfs] btrfs_finish_ordered_io+0x2f4/0x7f0 [btrfs] ? pick_next_task_fair+0x2cd/0x530 ? __switch_to+0x92/0x4b0 btrfs_worker_helper+0x81/0x300 [btrfs] process_one_work+0x1da/0x3f0 worker_thread+0x2b/0x3f0 ? process_one_work+0x3f0/0x3f0 kthread+0x11a/0x130 ? kthread_create_on_node+0x40/0x40 ret_from_fork+0x35/0x40 Code: 00 00 5b c3 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 40 80 ff 0c 40 0f b6 c7 77 0b 48 c1 e0 04 8b 80 00 bf c8 bd c3 <0f> 0b b8 fb ff ff ff c3 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 ---[ end trace f079fb809e7a862b ]--- BTRFS critical (device vda2): unable to find logical 8820195328 length 16384 BTRFS: error (device vda2) in btrfs_finish_ordered_io:3023: errno=-5 IO failure BTRFS info (device vda2): forced readonly BTRFS error (device vda2): pending csums is 2887680 ------ [CAUSE] The problem is due to the fact that, btrfs block group auto removal only checks if a block group is unused by checking used_bytes of its block group item. However it's possible to have metadata block group whose used bytes is 0, but has pinned down bytes by delalloc. In that case, when the delalloc work is ran and quota is enabled, quota will try to resolve the parents, which could lead to read on tree blocks in the deleted block group. [FIX] Just teach btrfs_delete_unused_bgs() to skip block group who still has pinned bytes. Signed-off-by: Qu Wenruo --- fs/btrfs/extent-tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index f190023386a9..7d14c4ca8232 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -10675,7 +10675,7 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info) /* Don't want to race with allocators so take the groups_sem */ down_write(&space_info->groups_sem); spin_lock(&block_group->lock); - if (block_group->reserved || + if (block_group->reserved || block_group->pinned || btrfs_block_group_used(&block_group->item) || block_group->ro || list_is_singular(&block_group->list)) {