From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from demfloro.ru ([188.166.0.225]:56358 "EHLO demfloro.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751438AbdLNLCp (ORCPT ); Thu, 14 Dec 2017 06:02:45 -0500 Received: from [81.95.28.29] (helo=job) by demfloro.ru with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1ePRHm-0002vX-T2 for linux-btrfs@vger.kernel.org; Thu, 14 Dec 2017 11:02:44 +0000 Date: Thu, 14 Dec 2017 14:02:30 +0300 From: Dmitrii Tcvetkov To: linux-btrfs@vger.kernel.org Subject: WARN_ON in __writeback_inodes_sb_nr when btrfs mounted with flushoncommit Message-ID: <20171214140230.589485d8@job> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-btrfs-owner@vger.kernel.org List-ID: Since 4.15-rc1 if btrfs filesystem is mounted with flushoncommit mount option then during fsync this trace appears in dmesg: [ 17.323092] WARNING: CPU: 0 PID: 364 at fs/fs-writeback.c:2339 __writeback_inodes_sb_nr+0xbf/0xd0 [ 17.323925] Modules linked in: [ 17.324697] CPU: 0 PID: 364 Comm: systemd-journal Not tainted 4.15.0-rc3 #2 [ 17.325424] Hardware name: To be filled by O.E.M. To be filled by O.E.M./SABERTOOTH 990FX R2.0, BIOS 2901 05/04/2016 [ 17.326177] RIP: 0010:__writeback_inodes_sb_nr+0xbf/0xd0 [ 17.326875] RSP: 0018:ffff8bcd40a77d08 EFLAGS: 00010246 [ 17.327598] RAX: 0000000000000000 RBX: ffff8a3fa9764488 RCX: 0000000000000000 [ 17.328321] RDX: 0000000000000002 RSI: 00000000000018ae RDI: ffff8a3fa96c7070 [ 17.329012] RBP: ffff8bcd40a77d0c R08: ffffffffffffff80 R09: 00000000000000ff [ 17.329740] R10: ffff8bcd40a77c10 R11: 0000000000001000 R12: 0000000000000000 [ 17.330439] R13: ffff8a3fa915e698 R14: ffff8a3fb04ed780 R15: ffff8a3fa9a16610 [ 17.331169] FS: 00007f72d53338c0(0000) GS:ffff8a3fbec00000(0000) knlGS:0000000000000000 [ 17.331880] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 17.332624] CR2: 00007f72d09a5000 CR3: 0000000329334000 CR4: 00000000000406f0 [ 17.333383] Call Trace: [ 17.334113] btrfs_commit_transaction+0x857/0x920 [ 17.334874] btrfs_sync_file+0x30c/0x3e0 [ 17.335622] do_fsync+0x33/0x60 [ 17.336332] SyS_fsync+0x7/0x10 [ 17.337069] do_syscall_64+0x63/0x360 [ 17.337776] entry_SYSCALL64_slow_path+0x25/0x25 [ 17.338513] RIP: 0033:0x7f72d4f29094 [ 17.339244] RSP: 002b:00007ffd71b078f8 EFLAGS: 00000246 ORIG_RAX: 000000000000004a [ 17.339962] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f72d4f29094 [ 17.340718] RDX: 0000000000090000 RSI: 00005630b6f8b090 RDI: 0000000000000010 [ 17.341431] RBP: 00005630b6f8b090 R08: 00000000000fffff R09: 0000000000000000 [ 17.342169] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000010 [ 17.342902] R13: 00005630b6f88f60 R14: 0000000000000001 R15: 0000000000000001 [ 17.343604] Code: df 0f b6 d1 e8 a3 fc ff ff 48 89 ee 48 89 df e8 78 f5 ff ff 48 8b 44 24 48 65 48 33 04 25 28 00 00 00 75 0b 48 83 c4 50 5b 5d c3 <0f> ff eb ca e8 38 1e ec ff 0f 1f 84 00 00 00 00 00 41 54 55 48 [ 17.344408] ---[ end trace ff4cf41ec70ec0a7 ]--- If fs mounted without flushoncommit then no warnings. Other mount options don't influence the behaviour. Steps to reproduce: mkfs.btrfs mount -o flushoncommit echo test > /test btrfs filesystem sync