[btrfs] WARNING: CPU: 0 PID: 6379 at fs/direct-io.c:293 dio_complete+0x1d4/0x220

[Fengguang Wu <fengguang.wu@intel.com>]

CC fsdevel.

On Sun, Oct 29, 2017 at 11:51:55PM +0100, Fengguang Wu wrote:
>Hi Linus,
>
>Up to now we see the below boot error/warnings when testing v4.14-rc6.
>
>They hit the RC release mainly due to various imperfections in 0day's
>auto bisection. So I manually list them here and CC the likely easy to
>debug ones to the corresponding maintainers in the followup emails.
>
>boot_successes: 4700
>boot_failures: 247

[...]

>WARNING:at_fs/direct-io.c:#dio_complete: 7
>WARNING:at_fs/iomap.c:#iomap_dio_complete: 3
>WARNING:at_fs/iomap.c:#iomap_dio_rw: 1

The first warning happens on btrfs and is bisected to this commit.
The other 2 warnings happen on xfs.

commit 332391a9935da939319e473b4680e173df75afcf
Author:     Lukas Czerner <lczerner@redhat.com>
AuthorDate: Thu Sep 21 08:16:29 2017 -0600
Commit:     Jens Axboe <axboe@kernel.dk>
CommitDate: Mon Sep 25 08:56:05 2017 -0600

    fs: Fix page cache inconsistency when mixing buffered and AIO DIO

    Currently when mixing buffered reads and asynchronous direct writes it
    is possible to end up with the situation where we have stale data in the
    page cache while the new data is already written to disk. This is
    permanent until the affected pages are flushed away. Despite the fact
    that mixing buffered and direct IO is ill-advised it does pose a thread
    for a data integrity, is unexpected and should be fixed.

    Fix this by deferring completion of asynchronous direct writes to a
    process context in the case that there are mapped pages to be found in
    the inode. Later before the completion in dio_complete() invalidate
    the pages in question. This ensures that after the completion the pages
    in the written area are either unmapped, or populated with up-to-date
    data. Also do the same for the iomap case which uses
    iomap_dio_complete() instead.

    This has a side effect of deferring the completion to a process context
    for every AIO DIO that happens on inode that has pages mapped. However
    since the consensus is that this is ill-advised practice the performance
    implication should not be a problem.

    This was based on proposal from Jeff Moyer, thanks!

    Reviewed-by: Jan Kara <jack@suse.cz>
    Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
    Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
    Signed-off-by: Lukas Czerner <lczerner@redhat.com>
    Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/direct-io.c | 47 ++++++++++++++++++++++++++++++++++++++++++-----
 fs/iomap.c     | 29 ++++++++++++++++-------------
 mm/filemap.c   |  6 ++++++
 3 files changed, 64 insertions(+), 18 deletions(-)

The call traces are:

[  334.461955] BTRFS info (device vdb): has skinny extents
[  334.463231] BTRFS info (device vdb): flagging fs with big metadata feature
[  334.469746] BTRFS info (device vdb): creating UUID tree
[  336.190840] ------------[ cut here ]------------
[  336.193338] WARNING: CPU: 0 PID: 6379 at fs/direct-io.c:293 dio_complete+0x1d4/0x220
[  336.196925] Modules linked in: btrfs xor zstd_decompress zstd_compress xxhash raid6_pq dm_mod rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver sr_mod cdrom sg ata_generic pata_acpi ppdev snd_pcm snd_timer snd soundcore serio_raw parport_pc pcspkr parport floppy ata_piix libata i2c_piix4 ip_tables
[  336.203746] CPU: 0 PID: 6379 Comm: kworker/0:0 Not tainted 4.14.0-rc6 #1
[  336.204799] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  336.207480] Workqueue: dio/vdb dio_aio_complete_work
[  336.208373] task: ffff880079094a80 task.stack: ffffc90000950000
[  336.210495] RIP: 0010:dio_complete+0x1d4/0x220
[  336.211288] RSP: 0018:ffffc90000953e20 EFLAGS: 00010286
[  336.213145] RAX: 00000000fffffff0 RBX: ffff8800aae8c780 RCX: ffffc90000953c70
[  336.214232] RDX: 0000000080000000 RSI: 00000000000002b4 RDI: ffffffff81cb9ccb
[  336.216605] RBP: ffffc90000953e48 R08: 0000000000000000 R09: ffff880079c8b6c0
[  336.217726] R10: 0000000000000074 R11: 0000000000000000 R12: 0000000000002000
[  336.220141] R13: 0000000000002000 R14: 0000000000000003 R15: 0000000000074000
[  336.221232] FS:  0000000000000000(0000) GS:ffff88013fc00000(0000) knlGS:0000000000000000
[  336.223915] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  336.224885] CR2: 000055e9eae6b750 CR3: 00000000752c7000 CR4: 00000000000006f0
[  336.227202] Call Trace:
[  336.227750]  dio_aio_complete_work+0x19/0x20
[  336.228536]  process_one_work+0x198/0x3e0
[  336.230396]  worker_thread+0x4e/0x3e0
[  336.231064]  kthread+0x114/0x150
[  336.232489]  ? process_one_work+0x3e0/0x3e0
[  336.233250]  ? kthread_create_on_node+0x40/0x40
[  336.234929]  ? kthread_create_on_node+0x40/0x40
[  336.235754]  ret_from_fork+0x25/0x30
[  336.237322] Code: 8b 78 30 48 83 7f 58 00 0f 84 e9 fe ff ff 4b 8d 54 27 ff 4c 89 fe 48 c1 fe 0c 48 c1 fa 0c e8 64 58 f3 ff 85 c0 0f 84 cc fe ff ff <0f> ff e9 c5 fe ff ff 8b 50 20 f6 c2 10 0f 84 e5 fe ff ff 48 8b
[  336.240031] ---[ end trace 3d29f0720cd16ad3 ]---
[  378.043462] generic/095       [failed, exit status 1] - output mismatch (see /lkp/benchmarks/xfstests/results//generic/095.out.bad)
[  378.043465]


[  121.160532] run fstests generic/117 at 2017-10-25 05:27:29
[  123.275347] XFS (vdd): Mounting V5 Filesystem
[  123.280579] XFS (vdd): Ending clean mount
[  163.043220] XFS (vdd): Unmounting Filesystem
[  163.258872] generic/117       42s
[  163.258875]
[  164.009187] run fstests generic/208 at 2017-10-25 05:28:12
[  164.344046] ------------[ cut here ]------------
[  164.345164] WARNING: CPU: 1 PID: 86 at fs/iomap.c:755 iomap_dio_complete+0xe5/0x100
[  164.347193] Modules linked in: xfs dm_mod rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver sr_mod cdrom sg ata_generic pata_acpi ppdev snd_pc
m snd_timer snd soundcore parport_pc pcspkr serio_raw floppy parport ata_piix i2c_piix4 libata ip_tables
[  164.351698] CPU: 1 PID: 86 Comm: kworker/1:2 Not tainted 4.14.0-rc6 #1
[  164.353111] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  164.361199] Workqueue: dio/vda iomap_dio_complete_work
[  164.362418] task: ffff88007f8b8000 task.stack: ffffc90000a4c000
[  164.363666] RIP: 0010:iomap_dio_complete+0xe5/0x100
[  164.364923] RSP: 0018:ffffc90000a4fe08 EFLAGS: 00010286
[  164.366065] RAX: 00000000fffffff0 RBX: ffff88007a5fba80 RCX: ffffc90000a4fc58
[  164.367281] RDX: 0000000080000000 RSI: 00000000000002b4 RDI: ffffffff81cb9ccb
[  164.368330] RBP: ffffc90000a4fe30 R08: 0000000000000000 R09: ffff8800750eeb58
[  164.369503] R10: 0000000000001ffe R11: 0000000000000000 R12: 0000000002000000
[  164.370573] R13: ffff8800b8d27780 R14: ffff8800b8869058 R15: 0000000000000000
[  164.371674] FS:  0000000000000000(0000) GS:ffff88013fc80000(0000) knlGS:0000000000000000
[  164.373136] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  164.387036] CR2: 00007f5ee028e000 CR3: 000000007a1ff000 CR4: 00000000000006e0
[  164.388119] Call Trace:
[  164.388581]  iomap_dio_complete_work+0x25/0x80
[  164.389385]  process_one_work+0x198/0x3e0
[  164.390054]  worker_thread+0x4e/0x3e0
[  164.390699]  kthread+0x114/0x150
[  164.391341]  ? process_one_work+0x3e0/0x3e0
[  164.392038]  ? kthread_create_on_node+0x40/0x40
[  164.392922]  ret_from_fork+0x25/0x30
[  164.393506] Code: e0 eb 9f 48 8b 77 18 e9 78 ff ff ff 4c 89 fa 48 03 53 18 4c 89 fe 48 c1 fe 0c 48 83 ea 01 48 c1 fa 0c e8 0f 93 f0 ff 85 c
0 74 93 <0f> ff eb 8f 4c 63 67 28 e9 54 ff ff ff 0f 1f 40 00 66 2e 0f 1f
[  164.396264] ---[ end trace 77984c98cc2335de ]---
[  364.297438] generic/208       200s
[  364.297442]
[  365.772872] XFS (vda): Unmounting Filesystem
[  366.507546] XFS (vda): Mounting V5 Filesystem
[  366.519283] XFS (vda): Ending clean mount


[  370.264428] run fstests generic/095 at 2017-10-25 05:38:44
[  370.392041] XFS (vdd): Unmounting Filesystem
[  372.641826] XFS (vdd): Mounting V5 Filesystem
[  372.648446] XFS (vdd): Ending clean mount
[  373.277786] ------------[ cut here ]------------
[  373.279820] ------------[ cut here ]------------
[  373.279826] WARNING: CPU: 2 PID: 29166 at fs/iomap.c:1016 iomap_dio_rw+0x346/0x360
[  373.279827] Modules linked in: xfs dm_mod rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver sr_mod cdrom sg ata_generic pata_acpi ppdev snd_pcm snd_timer snd soundcore serio_raw pcspkr i2c_piix4 ata_piix parport_pc parport floppy libata ip_tables
[  373.279842] CPU: 2 PID: 29166 Comm: fio Not tainted 4.14.0-rc6 #1
[  373.279843] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  373.279844] task: ffff88008bd34a80 task.stack: ffffc900065f8000
[  373.279846] RIP: 0010:iomap_dio_rw+0x346/0x360
[  373.279847] RSP: 0000:ffffc900065fbd40 EFLAGS: 00010286
[  373.279848] RAX: 00000000fffffff0 RBX: ffffc900065fbe98 RCX: ffffc900065fbb90
[  373.279848] RDX: 0000000080000000 RSI: 00000000000002b4 RDI: ffffffff81cb9ccb
[  373.279849] RBP: ffffc900065fbdd0 R08: 0000000000000000 R09: 00007f6fe0948000
[  373.279850] R10: ffff88013ffd2000 R11: 0000000000000400 R12: 000000000005f400
[  373.279850] R13: ffffc900065fbe70 R14: ffff88007a6fb7e0 R15: 0000000000000011
[  373.279852] FS:  00007f6fb3ce1700(0000) GS:ffff88013fd00000(0000) knlGS:0000000000000000
[  373.279852] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  373.279853] CR2: 00007f6fe088ac00 CR3: 0000000078eb7000 CR4: 00000000000006e0
[  373.279856] Call Trace:
[  373.279913]  ? xfs_file_aio_write_checks+0x137/0x190 [xfs]
[  373.279933]  xfs_file_dio_aio_write+0xec/0x260 [xfs]
[  373.279952]  ? xfs_file_dio_aio_write+0xec/0x260 [xfs]
[  373.279970]  xfs_file_write_iter+0x98/0x150 [xfs]
[  373.279972]  __vfs_write+0xd3/0x150
[  373.279974]  vfs_write+0xc7/0x1b0
[  373.279975]  SyS_pwrite64+0x76/0x90
[  373.279977]  entry_SYSCALL_64_fastpath+0x1a/0xa5
[  373.279979] RIP: 0033:0x7f6fcc3019d3
[  373.279979] RSP: 002b:00007f6fb3cdeb20 EFLAGS: 00000293 ORIG_RAX: 0000000000000012
[  373.279980] RAX: ffffffffffffffda RBX: 00007f6fb3ce1700 RCX: 00007f6fcc3019d3
[  373.279981] RDX: 0000000000000400 RSI: 000055e925caac00 RDI: 0000000000000004
[  373.279982] RBP: 00007f6fe095fee0 R08: 0000000000000000 R09: 00007f6fb3ce1700
[  373.279982] R10: 000000000005f400 R11: 0000000000000293 R12: 0000000000000000
[  373.279983] R13: 00007f6fe095fe2f R14: 0000000000000003 R15: 00007f6fe095fee0
[  373.279984] Code: 21 00 00 f6 58 2b 81 49 c7 44 24 08 00 00 00 00 4c 89 f7 e8 ed ec ff ff e9 13 fe ff ff 48 8d 7d a0 e8 2f a9 13 00 e9 33 ff ff ff <0f> ff e9 6a fe ff ff 48 c7 c0 f4 ff ff ff e9 f2 fd ff ff 90 90 
[  373.279998] ---[ end trace 01e002a8aa01ae25 ]---
[  373.334858] WARNING: CPU: 3 PID: 29158 at fs/iomap.c:755 iomap_dio_complete+0xe5/0x100
[  373.336817] Modules linked in: xfs dm_mod rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver sr_mod cdrom sg ata_generic pata_acpi ppdev snd_pcm snd_timer snd soundcore serio_raw pcspkr i2c_piix4 ata_piix parport_pc parport floppy libata ip_tables
[  373.341916] CPU: 3 PID: 29158 Comm: fio Tainted: G        W       4.14.0-rc6 #1
[  373.344151] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  373.346702] task: ffff88008bd32540 task.stack: ffffc900065c8000
[  373.348512] RIP: 0010:iomap_dio_complete+0xe5/0x100
[  373.349999] RSP: 0018:ffffc900065cbd08 EFLAGS: 00010286
[  373.351604] RAX: 00000000fffffff0 RBX: ffff88007a5611e0 RCX: ffffc900065cbb58
[  373.353690] RDX: 0000000080000000 RSI: 00000000000002b4 RDI: ffffffff81cb9ccb
[  373.355693] RBP: ffffc900065cbd30 R08: 0000000000000000 R09: 00007f6fe08cb000
[  373.357775] R10: ffffc900065cb8c8 R11: 0000000000000207 R12: 0000000000000400
[  373.359837] R13: ffffc900065cbe70 R14: ffff8800787657d8 R15: 0000000000002400
[  373.361878] FS:  00007f6fe095aa80(0000) GS:ffff88013fd80000(0000) knlGS:0000000000000000
[  373.364333] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  373.366071] CR2: 00007f6fcc38c1ee CR3: 000000007949a000 CR4: 00000000000006e0
[  373.368170] Call Trace:
[  373.369165]  ? iomap_dio_rw+0x2a6/0x360
[  373.370467]  iomap_dio_rw+0x333/0x360
[  373.371768]  xfs_file_dio_aio_write+0xec/0x260 [xfs]
[  373.373069]  ? xfs_file_dio_aio_write+0xec/0x260 [xfs]
[  373.374410]  xfs_file_write_iter+0x98/0x150 [xfs]
[  373.375820]  __vfs_write+0xd3/0x150
[  373.377096]  vfs_write+0xc7/0x1b0
[  373.378436]  SyS_pwrite64+0x76/0x90
[  373.379897]  entry_SYSCALL_64_fastpath+0x1a/0xa5
[  373.381488] RIP: 0033:0x7f6fcc3019d3
[  373.382781] RSP: 002b:00007f6fe0957ea0 EFLAGS: 00000293 ORIG_RAX: 0000000000000012
[  373.385064] RAX: ffffffffffffffda RBX: 000055e925cb07f0 RCX: 00007f6fcc3019d3
[  373.386913] RDX: 0000000000000400 RSI: 000055e925ca9800 RDI: 0000000000000005
[  373.388911] RBP: 0000000000000005 R08: 0000000000000000 R09: 00007f6fe095aa80
[  373.390588] R10: 0000000000002400 R11: 0000000000000293 R12: 00007f6fe095aa80
[  373.392296] R13: 00007f6fe0957ec0 R14: 0000000000000003 R15: 000055e925caf360
[  373.394229] Code: e0 eb 9f 48 8b 77 18 e9 78 ff ff ff 4c 89 fa 48 03 53 18 4c 89 fe 48 c1 fe 0c 48 83 ea 01 48 c1 fa 0c e8 0f 93 f0 ff 85 c0 74 93 <0f> ff eb 8f 4c 63 67 28 e9 54 ff ff ff 0f 1f 40 00 66 2e 0f 1f 
[  373.398812] ---[ end trace 01e002a8aa01ae26 ]---
[  392.887639] XFS (vdd): Unmounting Filesystem
[  392.985715] generic/095	 [failed, exit status 1] - output mismatch (see /lkp/benchmarks/xfstests/results//generic/095.out.bad)

Thanks,
Fengguang