On 14.12.2017 13:02, Dmitrii Tcvetkov wrote: > 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 ]---
So this is due to writeback_inodes_sb being called without holding s_umount. So 4.15-rc1 the first kernel that started exhibiting this or did you also see it with earlier kernel > > If fs mounted without flushoncommit then no warnings. Other mount options > don't influence the behaviour. > > Steps to reproduce: > mkfs.btrfs <block device> > mount -o flushoncommit <block device> <mountpoint> > echo test > <mountpoint>/test > btrfs filesystem sync <mountpoint> > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
