From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4E1EC433F5 for ; Fri, 17 Dec 2021 14:02:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232747AbhLQOCU (ORCPT ); Fri, 17 Dec 2021 09:02:20 -0500 Received: from out20-27.mail.aliyun.com ([115.124.20.27]:36182 "EHLO out20-27.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231337AbhLQOCT (ORCPT ); Fri, 17 Dec 2021 09:02:19 -0500 X-Alimail-AntiSpam: AC=CONTINUE;BC=0.04436326|-1;CH=green;DM=|CONTINUE|false|;DS=CONTINUE|ham_social|0.04242-0.00138574-0.956194;FP=0|0|0|0|0|-1|-1|-1;HT=ay29a033018047198;MF=wangyugui@e16-tech.com;NM=1;PH=DS;RN=1;RT=1;SR=0;TI=SMTPD_---.MHYD0o3_1639749737; Received: from 192.168.2.112(mailfrom:wangyugui@e16-tech.com fp:SMTPD_---.MHYD0o3_1639749737) by smtp.aliyun-inc.com(10.147.41.199); Fri, 17 Dec 2021 22:02:17 +0800 Date: Fri, 17 Dec 2021 22:02:23 +0800 From: Wang Yugui To: linux-btrfs@vger.kernel.org Subject: Re: [PATCH v2] btrfs: fix reserved space leak on log tree nodes after transaction abort In-Reply-To: <049306dd5efc8cbe11501e7efebf56f615ef7360.1639744398.git.fdmanana@suse.com> References: <049306dd5efc8cbe11501e7efebf56f615ef7360.1639744398.git.fdmanana@suse.com> Message-Id: <20211217220222.DF7C.409509F4@e16-tech.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.75.04 [en] Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Hi, fstests generic/648 still trigger this two WARNING (btrfs_put_block_group/btrfs_free_block_groups) even with this path. Best Regards Wang Yugui (wangyugui@e16-tech.com) 2021/12/17 > From: Filipe Manana > > After the recent changes by commit c2e39305299f01 ("btrfs: clear extent > buffer uptodate when we fail to write it") and its followup fix that has > the subject "btrfs: check WRITE_ERR when trying to read an extent buffer" > (not yet in Linus' tree), after a transaction abort we can often end up > not unreserving the space that was reserved for log tree extent buffers. > > This happens because if writeback for a log tree extent buffer failed, > than we have cleared the EXTENT_BUFFER_UPTODATE from the extent buffer > and we have also set the bit EXTENT_BUFFER_WRITE_ERR on it. Later on, > when trying to free the log tree with free_log_tree(), which iterates > over the tree, we can end up getting an -EIO error when trying to read > a node or leaf, since read_extent_buffer_pages() returns -EIO if an > extent buffer does not have EXTENT_BUFFER_UPTODATE set and has the > EXTENT_BUFFER_WRITE_ERR bit set. Getting that -EIO means we return > immediately as we can not iterate over the entire tree. > > In that case we never update the reserved space for every extent buffer > in the respective block group and space_info object. When this happens > we get the following traces when unmmounting the filesystem: > > [174957.284509] BTRFS: error (device dm-0) in cleanup_transaction:1913: errno=-5 IO failure > [174957.286497] BTRFS: error (device dm-0) in free_log_tree:3420: errno=-5 IO failure > [174957.399379] ------------[ cut here ]------------ > [174957.402497] WARNING: CPU: 2 PID: 3206883 at fs/btrfs/block-group.c:127 btrfs_put_block_group+0x77/0xb0 [btrfs] > [174957.407523] Modules linked in: btrfs overlay dm_zero (...) > [174957.424917] CPU: 2 PID: 3206883 Comm: umount Tainted: G W 5.16.0-rc5-btrfs-next-109 #1 > [174957.426689] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 > [174957.428716] RIP: 0010:btrfs_put_block_group+0x77/0xb0 [btrfs] > [174957.429717] Code: 21 48 8b bd (...) > [174957.432867] RSP: 0018:ffffb70d41cffdd0 EFLAGS: 00010206 > [174957.433632] RAX: 0000000000000001 RBX: ffff8b09c3848000 RCX: ffff8b0758edd1c8 > [174957.434689] RDX: 0000000000000001 RSI: ffffffffc0b467e7 RDI: ffff8b0758edd000 > [174957.436068] RBP: ffff8b0758edd000 R08: 0000000000000000 R09: 0000000000000000 > [174957.437114] R10: 0000000000000246 R11: 0000000000000000 R12: ffff8b09c3848148 > [174957.438140] R13: ffff8b09c3848198 R14: ffff8b0758edd188 R15: dead000000000100 > [174957.439317] FS: 00007f328fb82800(0000) GS:ffff8b0a2d200000(0000) knlGS:0000000000000000 > [174957.440402] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [174957.441164] CR2: 00007fff13563e98 CR3: 0000000404f4e005 CR4: 0000000000370ee0 > [174957.442117] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [174957.443076] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > [174957.443948] Call Trace: > [174957.444264] > [174957.444538] btrfs_free_block_groups+0x255/0x3c0 [btrfs] > [174957.445238] close_ctree+0x301/0x357 [btrfs] > [174957.445803] ? call_rcu+0x16c/0x290 > [174957.446250] generic_shutdown_super+0x74/0x120 > [174957.446832] kill_anon_super+0x14/0x30 > [174957.447305] btrfs_kill_super+0x12/0x20 [btrfs] > [174957.447890] deactivate_locked_super+0x31/0xa0 > [174957.448440] cleanup_mnt+0x147/0x1c0 > [174957.448888] task_work_run+0x5c/0xa0 > [174957.449336] exit_to_user_mode_prepare+0x1e5/0x1f0 > [174957.449934] syscall_exit_to_user_mode+0x16/0x40 > [174957.450512] do_syscall_64+0x48/0xc0 > [174957.450980] entry_SYSCALL_64_after_hwframe+0x44/0xae > [174957.451605] RIP: 0033:0x7f328fdc4a97 > [174957.452059] Code: 03 0c 00 f7 (...) > [174957.454320] RSP: 002b:00007fff13564ec8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 > [174957.455262] RAX: 0000000000000000 RBX: 00007f328feea264 RCX: 00007f328fdc4a97 > [174957.456131] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000560b8ae51dd0 > [174957.457118] RBP: 0000560b8ae51ba0 R08: 0000000000000000 R09: 00007fff13563c40 > [174957.458005] R10: 00007f328fe49fc0 R11: 0000000000000246 R12: 0000000000000000 > [174957.459113] R13: 0000560b8ae51dd0 R14: 0000560b8ae51cb0 R15: 0000000000000000 > [174957.460193] > [174957.460534] irq event stamp: 0 > [174957.461003] hardirqs last enabled at (0): [<0000000000000000>] 0x0 > [174957.461947] hardirqs last disabled at (0): [] copy_process+0x934/0x2040 > [174957.463147] softirqs last enabled at (0): [] copy_process+0x934/0x2040 > [174957.465116] softirqs last disabled at (0): [<0000000000000000>] 0x0 > [174957.466323] ---[ end trace bc7ee0c490bce3af ]--- > [174957.467282] ------------[ cut here ]------------ > [174957.468184] WARNING: CPU: 2 PID: 3206883 at fs/btrfs/block-group.c:3976 btrfs_free_block_groups+0x330/0x3c0 [btrfs] > [174957.470066] Modules linked in: btrfs overlay dm_zero (...) > [174957.483137] CPU: 2 PID: 3206883 Comm: umount Tainted: G W 5.16.0-rc5-btrfs-next-109 #1 > [174957.484691] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 > [174957.486853] RIP: 0010:btrfs_free_block_groups+0x330/0x3c0 [btrfs] > [174957.488050] Code: 00 00 00 ad de (...) > [174957.491479] RSP: 0018:ffffb70d41cffde0 EFLAGS: 00010206 > [174957.492520] RAX: ffff8b08d79310b0 RBX: ffff8b09c3848000 RCX: 0000000000000000 > [174957.493868] RDX: 0000000000000001 RSI: fffff443055ee600 RDI: ffffffffb1131846 > [174957.495183] RBP: ffff8b08d79310b0 R08: 0000000000000000 R09: 0000000000000000 > [174957.496580] R10: 0000000000000001 R11: 0000000000000000 R12: ffff8b08d7931000 > [174957.498027] R13: ffff8b09c38492b0 R14: dead000000000122 R15: dead000000000100 > [174957.499438] FS: 00007f328fb82800(0000) GS:ffff8b0a2d200000(0000) knlGS:0000000000000000 > [174957.500990] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [174957.502117] CR2: 00007fff13563e98 CR3: 0000000404f4e005 CR4: 0000000000370ee0 > [174957.503513] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [174957.504864] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > [174957.506167] Call Trace: > [174957.506654] > [174957.507047] close_ctree+0x301/0x357 [btrfs] > [174957.507867] ? call_rcu+0x16c/0x290 > [174957.508567] generic_shutdown_super+0x74/0x120 > [174957.509447] kill_anon_super+0x14/0x30 > [174957.510194] btrfs_kill_super+0x12/0x20 [btrfs] > [174957.511123] deactivate_locked_super+0x31/0xa0 > [174957.511976] cleanup_mnt+0x147/0x1c0 > [174957.512610] task_work_run+0x5c/0xa0 > [174957.513309] exit_to_user_mode_prepare+0x1e5/0x1f0 > [174957.514231] syscall_exit_to_user_mode+0x16/0x40 > [174957.515069] do_syscall_64+0x48/0xc0 > [174957.515718] entry_SYSCALL_64_after_hwframe+0x44/0xae > [174957.516688] RIP: 0033:0x7f328fdc4a97 > [174957.517413] Code: 03 0c 00 f7 d8 (...) > [174957.521052] RSP: 002b:00007fff13564ec8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 > [174957.522514] RAX: 0000000000000000 RBX: 00007f328feea264 RCX: 00007f328fdc4a97 > [174957.523950] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000560b8ae51dd0 > [174957.525375] RBP: 0000560b8ae51ba0 R08: 0000000000000000 R09: 00007fff13563c40 > [174957.526763] R10: 00007f328fe49fc0 R11: 0000000000000246 R12: 0000000000000000 > [174957.528058] R13: 0000560b8ae51dd0 R14: 0000560b8ae51cb0 R15: 0000000000000000 > [174957.529404] > [174957.529843] irq event stamp: 0 > [174957.530256] hardirqs last enabled at (0): [<0000000000000000>] 0x0 > [174957.531061] hardirqs last disabled at (0): [] copy_process+0x934/0x2040 > [174957.532075] softirqs last enabled at (0): [] copy_process+0x934/0x2040 > [174957.533083] softirqs last disabled at (0): [<0000000000000000>] 0x0 > [174957.533865] ---[ end trace bc7ee0c490bce3b0 ]--- > [174957.534452] BTRFS info (device dm-0): space_info 4 has 1070841856 free, is not full > [174957.535404] BTRFS info (device dm-0): space_info total=1073741824, used=2785280, pinned=0, reserved=49152, may_use=0, readonly=65536 zone_unusable=0 > [174957.537029] BTRFS info (device dm-0): global_block_rsv: size 0 reserved 0 > [174957.537859] BTRFS info (device dm-0): trans_block_rsv: size 0 reserved 0 > [174957.538697] BTRFS info (device dm-0): chunk_block_rsv: size 0 reserved 0 > [174957.539552] BTRFS info (device dm-0): delayed_block_rsv: size 0 reserved 0 > [174957.540403] BTRFS info (device dm-0): delayed_refs_rsv: size 0 reserved 0 > > This is often triggered with test cases generic/475 and generic/648 from > fstests, which makes the tests fail. > > So fix this by iterating over the io tree that contains the ranges of all > log tree metadata extents and call unaccount_log_buffer() for the range of > each metadata extent. This is only called during the transaction abort > path if we failed to walk over the entire log tree. > > Signed-off-by: Filipe Manana > --- > > V2: Added missing bit EXTENT_NEED_WAIT. > > fs/btrfs/tree-log.c | 32 ++++++++++++++++++++++++++++++-- > 1 file changed, 30 insertions(+), 2 deletions(-) > > diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c > index 4b89ac769347..9062073407fd 100644 > --- a/fs/btrfs/tree-log.c > +++ b/fs/btrfs/tree-log.c > @@ -3402,6 +3402,32 @@ int btrfs_sync_log(struct btrfs_trans_handle *trans, > return ret; > } > > +/* > + * If when freeing a log tree we fail to iterate over the entire tree due to a > + * past writeback failure, then we have not properly freed every metadata extent. > + * In that case we use this function that does not iterate the log tree but it > + * still adjusts the reserved bytes in the block group of each metadata extent. > + */ > +static void unaccount_all_log_buffers(struct btrfs_root *log) > +{ > + struct btrfs_fs_info *fs_info = log->fs_info; > + u64 start = 0; > + u64 end; > + > + while (!find_first_extent_bit(&log->dirty_log_pages, start, &start, &end, > + EXTENT_DIRTY | EXTENT_NEW | EXTENT_NEED_WAIT, NULL)) { > + u64 bytenr; > + > + for (bytenr = start; bytenr < end; bytenr += fs_info->nodesize) { > + unaccount_log_buffer(fs_info, bytenr); > + cond_resched(); > + } > + > + start = end + 1; > + } > + > +} > + > static void free_log_tree(struct btrfs_trans_handle *trans, > struct btrfs_root *log) > { > @@ -3414,10 +3440,12 @@ static void free_log_tree(struct btrfs_trans_handle *trans, > if (log->node) { > ret = walk_log_tree(trans, log, &wc); > if (ret) { > - if (trans) > + if (trans) { > btrfs_abort_transaction(trans, ret); > - else > + } else { > btrfs_handle_fs_error(log->fs_info, ret, NULL); > + unaccount_all_log_buffers(log); > + } > } > } > > -- > 2.33.0