XFS hang - 4.4.73 longterm

XFS hang - 4.4.73 longterm

[Markus Stockhausen]

[-- Attachment #1: Type: text/plain, Size: 6076 bytes --]

Hi,

we are using a NFS/XFS fileserver and installed the current 4.4.73 longterm kernel.
>From time to time (reason currently unidentified) it spits blocked for 120s messages
Like the attached ones. Any ideas what might be the reason? I can reproduce it
With some effort. So in case you want some more logging don't hesitate to ask.

For more details see https://bugzilla.kernel.org/show_bug.cgi?id=196259

[1248134.772889] INFO: task nfsd:1623 blocked for more than 120 seconds.
[1248134.772895]       Tainted: G          I     4.4.73-2.el7.centos.x86_64 #1
[1248134.772897] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[1248134.772899] nfsd            D ffff880bbf08b9c8     0  1623      2 0x00000080
[1248134.772905]  ffff880bbf08b9c8 ffff880be0875400 ffff880bbf080000 ffff880bbf08c000
[1248134.772908]  0000000000000000 7fffffffffffffff ffff880bbf08bb38 ffffffff816fbb40
[1248134.772911]  ffff880bbf08b9e0 ffffffff816fb2d5 ffff880c176d6d00 ffff880bbf08ba88
[1248134.772915] Call Trace:
[1248134.772923]  [<ffffffff816fbb40>] ? bit_wait+0x50/0x50
[1248134.772926]  [<ffffffff816fb2d5>] schedule+0x35/0x80
[1248134.772929]  [<ffffffff816fdfe7>] schedule_timeout+0x237/0x2d0
[1248134.772935]  [<ffffffff8161ee0e>] ? ip_output+0x6e/0xe0
[1248134.772938]  [<ffffffff8161e502>] ? __ip_local_out+0x92/0x110
[1248134.772941]  [<ffffffff810f303a>] ? ktime_get+0x3a/0x90
[1248134.772944]  [<ffffffff816fbb40>] ? bit_wait+0x50/0x50
[1248134.772947]  [<ffffffff816faa46>] io_schedule_timeout+0xa6/0x110
[1248134.772950]  [<ffffffff816fbb5b>] bit_wait_io+0x1b/0x60
[1248134.772952]  [<ffffffff816fb8ee>] __wait_on_bit_lock+0x4e/0xb0
[1248134.772958]  [<ffffffff81189759>] __lock_page+0xb9/0xe0
[1248134.772962]  [<ffffffff810c2910>] ? autoremove_wake_function+0x40/0x40
[1248134.773007]  [<ffffffffa08d7c70>] xfs_find_get_desired_pgoff.isra.10+0x1e0/0x2d0 [xfs]
[1248134.773039]  [<ffffffffa08d7f9d>] xfs_seek_hole_data+0x23d/0x2c0 [xfs]
[1248134.773054]  [<ffffffffa05d942c>] ? nfs4_preprocess_stateid_op+0x11c/0x430 [nfsd]
[1248134.773086]  [<ffffffffa08d803c>] xfs_file_llseek+0x1c/0x40 [xfs]
[1248134.773090]  [<ffffffff8120633e>] vfs_llseek+0x2e/0x30
[1248134.773101]  [<ffffffffa05c6080>] nfsd4_seek+0x80/0xe0 [nfsd]
[1248134.773112]  [<ffffffffa05c8416>] nfsd4_proc_compound+0x3b6/0x710 [nfsd]
[1248134.773121]  [<ffffffffa05b4f2e>] nfsd_dispatch+0xce/0x270 [nfsd]
[1248134.773142]  [<ffffffffa01a5134>] svc_process_common+0x454/0x720 [sunrpc]
[1248134.773151]  [<ffffffffa05b4880>] ? nfsd_destroy+0x60/0x60 [nfsd]
[1248134.773168]  [<ffffffffa01a5505>] svc_process+0x105/0x1c0 [sunrpc]
[1248134.773177]  [<ffffffffa05b4970>] nfsd+0xf0/0x160 [nfsd]
[1248134.773180]  [<ffffffff8109d755>] kthread+0xe5/0x100
[1248134.773183]  [<ffffffff8109d670>] ? kthread_park+0x60/0x60
[1248134.773187]  [<ffffffff816ff1cf>] ret_from_fork+0x3f/0x70
[1248134.773190]  [<ffffffff8109d670>] ? kthread_park+0x60/0x60
[1248134.773193] INFO: task nfsd:1624 blocked for more than 120 seconds.
[1248134.773195]       Tainted: G          I     4.4.73-2.el7.centos.x86_64 #1
[1248134.773197] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[1248134.773198] nfsd            D ffff880bbf1a7738     0  1624      2 0x00000080
[1248134.773202]  ffff880bbf1a7738 ffffffff81a79500 ffff880bbf081500 ffff880bbf1a8000
[1248134.773205]  ffff8802334477a8 ffff880233447790 ffffffff00000000 ffffffff00000001
[1248134.773208]  ffff880bbf1a7750 ffffffff816fb2d5 ffff880bbf081500 ffff880bbf1a77e0
[1248134.773211] Call Trace:
[1248134.773214]  [<ffffffff816fb2d5>] schedule+0x35/0x80
[1248134.773217]  [<ffffffff816fdab5>] rwsem_down_write_failed+0x1f5/0x320
[1248134.773243]  [<ffffffffa089e722>] ? xfs_bmap_search_extents+0x72/0xe0 [xfs]
[1248134.773273]  [<ffffffffa08cd212>] ? __xfs_get_blocks+0x162/0x800 [xfs]
[1248134.773276]  [<ffffffff81346433>] call_rwsem_down_write_failed+0x13/0x20
[1248134.773279]  [<ffffffff816fd35d>] ? down_write+0x2d/0x40
[1248134.773311]  [<ffffffffa08e459a>] xfs_ilock+0xea/0x130 [xfs]
[1248134.773341]  [<ffffffffa08cd212>] __xfs_get_blocks+0x162/0x800 [xfs]
[1248134.773371]  [<ffffffffa08cd8c4>] xfs_get_blocks+0x14/0x20 [xfs]
[1248134.773375]  [<ffffffff8123f349>] __block_write_begin+0x1a9/0x4c0
[1248134.773405]  [<ffffffffa08cd8b0>] ? __xfs_get_blocks+0x800/0x800 [xfs]
[1248134.773435]  [<ffffffffa08cbae1>] xfs_vm_write_begin+0x51/0xe0 [xfs]
[1248134.773464]  [<ffffffffa08cb8f9>] ? xfs_vm_write_end+0x29/0x80 [xfs]
[1248134.773468]  [<ffffffff81189aef>] generic_perform_write+0xcf/0x1c0
[1248134.773499]  [<ffffffffa08d9615>] xfs_file_buffered_aio_write+0x135/0x290 [xfs]
[1248134.773503]  [<ffffffff812bae93>] ? selinux_file_permission+0xc3/0x110
[1248134.773534]  [<ffffffffa08d9801>] xfs_file_write_iter+0x91/0x150 [xfs]
[1248134.773566]  [<ffffffffa08d9770>] ? xfs_file_buffered_aio_write+0x290/0x290 [xfs]
[1248134.773569]  [<ffffffff812072dc>] do_readv_writev+0x1ec/0x2a0
[1248134.773573]  [<ffffffff816fe8a5>] ? _raw_spin_unlock_irqrestore+0x15/0x20
[1248134.773576]  [<ffffffff810c22f4>] ? __wake_up+0x44/0x50
[1248134.773579]  [<ffffffff81207419>] vfs_writev+0x39/0x50
[1248134.773589]  [<ffffffffa05b9d40>] nfsd_vfs_write+0xc0/0x370 [nfsd]
[1248134.773600]  [<ffffffffa05c64a3>] nfsd4_write+0x1a3/0x200 [nfsd]
[1248134.773611]  [<ffffffffa05c8416>] nfsd4_proc_compound+0x3b6/0x710 [nfsd]
[1248134.773620]  [<ffffffffa05b4f2e>] nfsd_dispatch+0xce/0x270 [nfsd]
[1248134.773638]  [<ffffffffa01a5134>] svc_process_common+0x454/0x720 [sunrpc]
[1248134.773647]  [<ffffffffa05b4880>] ? nfsd_destroy+0x60/0x60 [nfsd]
[1248134.773664]  [<ffffffffa01a5505>] svc_process+0x105/0x1c0 [sunrpc]
[1248134.773672]  [<ffffffffa05b4970>] nfsd+0xf0/0x160 [nfsd]
[1248134.773675]  [<ffffffff8109d755>] kthread+0xe5/0x100
[1248134.773678]  [<ffffffff8109d670>] ? kthread_park+0x60/0x60
[1248134.773682]  [<ffffffff816ff1cf>] ret_from_fork+0x3f/0x70
[1248134.773684]  [<ffffffff8109d670>] ? kthread_park+0x60/0x60

Thanks in advance.

Markus

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Collogia
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Re: XFS hang - 4.4.73 longterm

[Darrick J. Wong]

On Wed, Jul 05, 2017 at 07:19:28PM +0000, Markus Stockhausen wrote:
> Hi,
> 
> we are using a NFS/XFS fileserver and installed the current 4.4.73 longterm kernel.
> From time to time (reason currently unidentified) it spits blocked for 120s messages
> Like the attached ones. Any ideas what might be the reason? I can reproduce it
> With some effort. So in case you want some more logging don't hesitate to ask.
> 
> For more details see https://bugzilla.kernel.org/show_bug.cgi?id=196259
> 
> [1248134.772889] INFO: task nfsd:1623 blocked for more than 120 seconds.
> [1248134.772895]       Tainted: G          I     4.4.73-2.el7.centos.x86_64 #1
> [1248134.772897] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> [1248134.772899] nfsd            D ffff880bbf08b9c8     0  1623      2 0x00000080
> [1248134.772905]  ffff880bbf08b9c8 ffff880be0875400 ffff880bbf080000 ffff880bbf08c000
> [1248134.772908]  0000000000000000 7fffffffffffffff ffff880bbf08bb38 ffffffff816fbb40
> [1248134.772911]  ffff880bbf08b9e0 ffffffff816fb2d5 ffff880c176d6d00 ffff880bbf08ba88
> [1248134.772915] Call Trace:
> [1248134.772923]  [<ffffffff816fbb40>] ? bit_wait+0x50/0x50
> [1248134.772926]  [<ffffffff816fb2d5>] schedule+0x35/0x80
> [1248134.772929]  [<ffffffff816fdfe7>] schedule_timeout+0x237/0x2d0
> [1248134.772935]  [<ffffffff8161ee0e>] ? ip_output+0x6e/0xe0
> [1248134.772938]  [<ffffffff8161e502>] ? __ip_local_out+0x92/0x110
> [1248134.772941]  [<ffffffff810f303a>] ? ktime_get+0x3a/0x90
> [1248134.772944]  [<ffffffff816fbb40>] ? bit_wait+0x50/0x50
> [1248134.772947]  [<ffffffff816faa46>] io_schedule_timeout+0xa6/0x110
> [1248134.772950]  [<ffffffff816fbb5b>] bit_wait_io+0x1b/0x60
> [1248134.772952]  [<ffffffff816fb8ee>] __wait_on_bit_lock+0x4e/0xb0
> [1248134.772958]  [<ffffffff81189759>] __lock_page+0xb9/0xe0

Waiting for a page lock with ILOCK held...

> [1248134.772962]  [<ffffffff810c2910>] ? autoremove_wake_function+0x40/0x40
> [1248134.773007]  [<ffffffffa08d7c70>] xfs_find_get_desired_pgoff.isra.10+0x1e0/0x2d0 [xfs]
> [1248134.773039]  [<ffffffffa08d7f9d>] xfs_seek_hole_data+0x23d/0x2c0 [xfs]
> [1248134.773054]  [<ffffffffa05d942c>] ? nfs4_preprocess_stateid_op+0x11c/0x430 [nfsd]
> [1248134.773086]  [<ffffffffa08d803c>] xfs_file_llseek+0x1c/0x40 [xfs]
> [1248134.773090]  [<ffffffff8120633e>] vfs_llseek+0x2e/0x30
> [1248134.773101]  [<ffffffffa05c6080>] nfsd4_seek+0x80/0xe0 [nfsd]
> [1248134.773112]  [<ffffffffa05c8416>] nfsd4_proc_compound+0x3b6/0x710 [nfsd]
> [1248134.773121]  [<ffffffffa05b4f2e>] nfsd_dispatch+0xce/0x270 [nfsd]
> [1248134.773142]  [<ffffffffa01a5134>] svc_process_common+0x454/0x720 [sunrpc]
> [1248134.773151]  [<ffffffffa05b4880>] ? nfsd_destroy+0x60/0x60 [nfsd]
> [1248134.773168]  [<ffffffffa01a5505>] svc_process+0x105/0x1c0 [sunrpc]
> [1248134.773177]  [<ffffffffa05b4970>] nfsd+0xf0/0x160 [nfsd]
> [1248134.773180]  [<ffffffff8109d755>] kthread+0xe5/0x100
> [1248134.773183]  [<ffffffff8109d670>] ? kthread_park+0x60/0x60
> [1248134.773187]  [<ffffffff816ff1cf>] ret_from_fork+0x3f/0x70
> [1248134.773190]  [<ffffffff8109d670>] ? kthread_park+0x60/0x60
> [1248134.773193] INFO: task nfsd:1624 blocked for more than 120 seconds.
> [1248134.773195]       Tainted: G          I     4.4.73-2.el7.centos.x86_64 #1
> [1248134.773197] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> [1248134.773198] nfsd            D ffff880bbf1a7738     0  1624      2 0x00000080
> [1248134.773202]  ffff880bbf1a7738 ffffffff81a79500 ffff880bbf081500 ffff880bbf1a8000
> [1248134.773205]  ffff8802334477a8 ffff880233447790 ffffffff00000000 ffffffff00000001
> [1248134.773208]  ffff880bbf1a7750 ffffffff816fb2d5 ffff880bbf081500 ffff880bbf1a77e0
> [1248134.773211] Call Trace:
> [1248134.773214]  [<ffffffff816fb2d5>] schedule+0x35/0x80
> [1248134.773217]  [<ffffffff816fdab5>] rwsem_down_write_failed+0x1f5/0x320
> [1248134.773243]  [<ffffffffa089e722>] ? xfs_bmap_search_extents+0x72/0xe0 [xfs]
> [1248134.773273]  [<ffffffffa08cd212>] ? __xfs_get_blocks+0x162/0x800 [xfs]
> [1248134.773276]  [<ffffffff81346433>] call_rwsem_down_write_failed+0x13/0x20
> [1248134.773279]  [<ffffffff816fd35d>] ? down_write+0x2d/0x40
> [1248134.773311]  [<ffffffffa08e459a>] xfs_ilock+0xea/0x130 [xfs]

...and waiting for the ILOCK with page lock held.

This is the known deadlock in SEEK_HOLE/SEEK_DATA; I have patches queued
to fix it in 4.13, as soon as the dust settles and I send the pull req.

--D

> [1248134.773341]  [<ffffffffa08cd212>] __xfs_get_blocks+0x162/0x800 [xfs]
> [1248134.773371]  [<ffffffffa08cd8c4>] xfs_get_blocks+0x14/0x20 [xfs]
> [1248134.773375]  [<ffffffff8123f349>] __block_write_begin+0x1a9/0x4c0
> [1248134.773405]  [<ffffffffa08cd8b0>] ? __xfs_get_blocks+0x800/0x800 [xfs]
> [1248134.773435]  [<ffffffffa08cbae1>] xfs_vm_write_begin+0x51/0xe0 [xfs]
> [1248134.773464]  [<ffffffffa08cb8f9>] ? xfs_vm_write_end+0x29/0x80 [xfs]
> [1248134.773468]  [<ffffffff81189aef>] generic_perform_write+0xcf/0x1c0
> [1248134.773499]  [<ffffffffa08d9615>] xfs_file_buffered_aio_write+0x135/0x290 [xfs]
> [1248134.773503]  [<ffffffff812bae93>] ? selinux_file_permission+0xc3/0x110
> [1248134.773534]  [<ffffffffa08d9801>] xfs_file_write_iter+0x91/0x150 [xfs]
> [1248134.773566]  [<ffffffffa08d9770>] ? xfs_file_buffered_aio_write+0x290/0x290 [xfs]
> [1248134.773569]  [<ffffffff812072dc>] do_readv_writev+0x1ec/0x2a0
> [1248134.773573]  [<ffffffff816fe8a5>] ? _raw_spin_unlock_irqrestore+0x15/0x20
> [1248134.773576]  [<ffffffff810c22f4>] ? __wake_up+0x44/0x50
> [1248134.773579]  [<ffffffff81207419>] vfs_writev+0x39/0x50
> [1248134.773589]  [<ffffffffa05b9d40>] nfsd_vfs_write+0xc0/0x370 [nfsd]
> [1248134.773600]  [<ffffffffa05c64a3>] nfsd4_write+0x1a3/0x200 [nfsd]
> [1248134.773611]  [<ffffffffa05c8416>] nfsd4_proc_compound+0x3b6/0x710 [nfsd]
> [1248134.773620]  [<ffffffffa05b4f2e>] nfsd_dispatch+0xce/0x270 [nfsd]
> [1248134.773638]  [<ffffffffa01a5134>] svc_process_common+0x454/0x720 [sunrpc]
> [1248134.773647]  [<ffffffffa05b4880>] ? nfsd_destroy+0x60/0x60 [nfsd]
> [1248134.773664]  [<ffffffffa01a5505>] svc_process+0x105/0x1c0 [sunrpc]
> [1248134.773672]  [<ffffffffa05b4970>] nfsd+0xf0/0x160 [nfsd]
> [1248134.773675]  [<ffffffff8109d755>] kthread+0xe5/0x100
> [1248134.773678]  [<ffffffff8109d670>] ? kthread_park+0x60/0x60
> [1248134.773682]  [<ffffffff816ff1cf>] ret_from_fork+0x3f/0x70
> [1248134.773684]  [<ffffffff8109d670>] ? kthread_park+0x60/0x60
> 
> Thanks in advance.
> 
> Markus

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> manipuliert werden. Deshalb ist diese als E-Mail verschickte Nachricht keine
> rechtsverbindliche Willenserkl??rung.
> 
> Collogia
> Unternehmensberatung AG
> Ubierring 11
> D-50678 K??ln
> 
> Vorstand:
> Kadir Akin
> Dr. Michael H??hnerbach
> 
> Vorsitzender des Aufsichtsrates:
> Hans Kristian Langva
> 
> Registergericht: Amtsgericht K??ln
> Registernummer: HRB 52 497
> 
> This e-mail may contain confidential and/or privileged information. If you
> are not the intended recipient (or have received this e-mail in error)
> please notify the sender immediately and destroy this e-mail. Any
> unauthorized copying, disclosure or distribution of the material in this
> e-mail is strictly forbidden.
> 
> e-mails sent over the internet may have been written under a wrong name or
> been manipulated. That is why this message sent as an e-mail is not a
> legally binding declaration of intention.
> 
> Collogia
> Unternehmensberatung AG
> Ubierring 11
> D-50678 K??ln
> 
> executive board:
> Kadir Akin
> Dr. Michael H??hnerbach
> 
> President of the supervisory board:
> Hans Kristian Langva
> 
> Registry office: district court Cologne
> Register number: HRB 52 497
> 
> ****************************************************************************

AW: XFS hang - 4.4.73 longterm

[Markus Stockhausen]

[-- Attachment #1: Type: text/plain, Size: 5337 bytes --]

> Von: linux-xfs-owner@vger.kernel.org [mailto:linux-xfs-owner@vger.kernel.org] Im Auftrag von Darrick J. Wong
> Gesendet: Donnerstag, 6. Juli 2017 02:25
> An: Markus Stockhausen
> Cc: 'linux-xfs@vger.kernel.org'
> Betreff: Re: XFS hang - 4.4.73 longterm
>
> On Wed, Jul 05, 2017 at 07:19:28PM +0000, Markus Stockhausen wrote:
> > Hi,
> > 
> > we are using a NFS/XFS fileserver and installed the current 4.4.73 longterm kernel.
> > From time to time (reason currently unidentified) it spits blocked for 
> > 120s messages Like the attached ones. Any ideas what might be the 
> > reason? I can reproduce it With some effort. So in case you want some more logging don't hesitate to ask.
> > 
> > For more details see 
> > https://bugzilla.kernel.org/show_bug.cgi?id=196259
> > 
> > [1248134.772889] INFO: task nfsd:1623 blocked for more than 120 seconds.
> > [1248134.772895]       Tainted: G          I     4.4.73-2.el7.centos.x86_64 #1
> > [1248134.772897] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> > [1248134.772899] nfsd            D ffff880bbf08b9c8     0  1623      2 0x00000080
> > [1248134.772905]  ffff880bbf08b9c8 ffff880be0875400 ffff880bbf080000 
> > ffff880bbf08c000 [1248134.772908]  0000000000000000 7fffffffffffffff 
> > ffff880bbf08bb38 ffffffff816fbb40 [1248134.772911]  ffff880bbf08b9e0 
> > ffffffff816fb2d5 ffff880c176d6d00 ffff880bbf08ba88 [1248134.772915] Call Trace:
> > [1248134.772923]  [<ffffffff816fbb40>] ? bit_wait+0x50/0x50 
> > [1248134.772926]  [<ffffffff816fb2d5>] schedule+0x35/0x80 
> > [1248134.772929]  [<ffffffff816fdfe7>] schedule_timeout+0x237/0x2d0 
> > [1248134.772935]  [<ffffffff8161ee0e>] ? ip_output+0x6e/0xe0 
> > [1248134.772938]  [<ffffffff8161e502>] ? __ip_local_out+0x92/0x110 
> > [1248134.772941]  [<ffffffff810f303a>] ? ktime_get+0x3a/0x90 
> > [1248134.772944]  [<ffffffff816fbb40>] ? bit_wait+0x50/0x50 
> > [1248134.772947]  [<ffffffff816faa46>] io_schedule_timeout+0xa6/0x110 
> > [1248134.772950]  [<ffffffff816fbb5b>] bit_wait_io+0x1b/0x60 
> > [1248134.772952]  [<ffffffff816fb8ee>] __wait_on_bit_lock+0x4e/0xb0 
> > [1248134.772958]  [<ffffffff81189759>] __lock_page+0xb9/0xe0
>
> Waiting for a page lock with ILOCK held...
>
> > [1248134.772962]  [<ffffffff810c2910>] ? 
> > autoremove_wake_function+0x40/0x40
> > [1248134.773007]  [<ffffffffa08d7c70>] 
> > xfs_find_get_desired_pgoff.isra.10+0x1e0/0x2d0 [xfs] [1248134.773039]  
> > [<ffffffffa08d7f9d>] xfs_seek_hole_data+0x23d/0x2c0 [xfs] 
> > [1248134.773054]  [<ffffffffa05d942c>] ? 
> > nfs4_preprocess_stateid_op+0x11c/0x430 [nfsd] [1248134.773086]  
> > [<ffffffffa08d803c>] xfs_file_llseek+0x1c/0x40 [xfs] [1248134.773090]  
> > [<ffffffff8120633e>] vfs_llseek+0x2e/0x30 [1248134.773101]  
> > [<ffffffffa05c6080>] nfsd4_seek+0x80/0xe0 [nfsd] [1248134.773112]  
> > [<ffffffffa05c8416>] nfsd4_proc_compound+0x3b6/0x710 [nfsd] 
> > [1248134.773121]  [<ffffffffa05b4f2e>] nfsd_dispatch+0xce/0x270 [nfsd] 
> > [1248134.773142]  [<ffffffffa01a5134>] svc_process_common+0x454/0x720 
> > [sunrpc] [1248134.773151]  [<ffffffffa05b4880>] ? 
> > nfsd_destroy+0x60/0x60 [nfsd] [1248134.773168]  [<ffffffffa01a5505>] 
> > svc_process+0x105/0x1c0 [sunrpc] [1248134.773177]  
> > [<ffffffffa05b4970>] nfsd+0xf0/0x160 [nfsd] [1248134.773180]  
> > [<ffffffff8109d755>] kthread+0xe5/0x100 [1248134.773183]  
> > [<ffffffff8109d670>] ? kthread_park+0x60/0x60 [1248134.773187]  
> > [<ffffffff816ff1cf>] ret_from_fork+0x3f/0x70 [1248134.773190]  
>  > [<ffffffff8109d670>] ? kthread_park+0x60/0x60 [1248134.773193] 
> > INFO: task nfsd:1624 blocked for more than 120 seconds.
> > [1248134.773195]       Tainted: G          I     4.4.73-2.el7.centos.x86_64 #1
> > [1248134.773197] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> > [1248134.773198] nfsd            D ffff880bbf1a7738     0  1624      2 0x00000080
> > [1248134.773202]  ffff880bbf1a7738 ffffffff81a79500 ffff880bbf081500 
> > ffff880bbf1a8000 [1248134.773205]  ffff8802334477a8 ffff880233447790 
> > ffffffff00000000 ffffffff00000001 [1248134.773208]  ffff880bbf1a7750 
> > ffffffff816fb2d5 ffff880bbf081500 ffff880bbf1a77e0 [1248134.773211] Call Trace:
> > [1248134.773214]  [<ffffffff816fb2d5>] schedule+0x35/0x80 
> > [1248134.773217]  [<ffffffff816fdab5>] 
> > rwsem_down_write_failed+0x1f5/0x320
> > [1248134.773243]  [<ffffffffa089e722>] ? 
> > xfs_bmap_search_extents+0x72/0xe0 [xfs] [1248134.773273]  
> > [<ffffffffa08cd212>] ? __xfs_get_blocks+0x162/0x800 [xfs] 
> > [1248134.773276]  [<ffffffff81346433>] 
> > call_rwsem_down_write_failed+0x13/0x20
> > [1248134.773279]  [<ffffffff816fd35d>] ? down_write+0x2d/0x40 
> > [1248134.773311]  [<ffffffffa08e459a>] xfs_ilock+0xea/0x130 [xfs]
>
>...and waiting for the ILOCK with page lock held.
>
> This is the known deadlock in SEEK_HOLE/SEEK_DATA; I have patches queued to fix it in 4.13, as soon as the dust settles and I send the pull req.

Short, precise, frightening.

Can you advise what will the best option to avoid that error. 
First things that come to my mind would be:

- get back to original 3.10 stable kernel from CentOS Distro 
- lower NFS mount version
- Maybe remove some single patch that introduced the error?

Thanks in advance.

Markus

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****************************************************************************

Re: XFS hang - 4.4.73 longterm

[Darrick J. Wong]

On Thu, Jul 06, 2017 at 04:45:43AM +0000, Markus Stockhausen wrote:
> > Von: linux-xfs-owner@vger.kernel.org [mailto:linux-xfs-owner@vger.kernel.org] Im Auftrag von Darrick J. Wong
> > Gesendet: Donnerstag, 6. Juli 2017 02:25
> > An: Markus Stockhausen
> > Cc: 'linux-xfs@vger.kernel.org'
> > Betreff: Re: XFS hang - 4.4.73 longterm
> >
> > On Wed, Jul 05, 2017 at 07:19:28PM +0000, Markus Stockhausen wrote:
> > > Hi,
> > > 
> > > we are using a NFS/XFS fileserver and installed the current 4.4.73 longterm kernel.
> > > From time to time (reason currently unidentified) it spits blocked for 
> > > 120s messages Like the attached ones. Any ideas what might be the 
> > > reason? I can reproduce it With some effort. So in case you want some more logging don't hesitate to ask.
> > > 
> > > For more details see 
> > > https://bugzilla.kernel.org/show_bug.cgi?id=196259
> > > 
> > > [1248134.772889] INFO: task nfsd:1623 blocked for more than 120 seconds.
> > > [1248134.772895]       Tainted: G          I     4.4.73-2.el7.centos.x86_64 #1
> > > [1248134.772897] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> > > [1248134.772899] nfsd            D ffff880bbf08b9c8     0  1623      2 0x00000080
> > > [1248134.772905]  ffff880bbf08b9c8 ffff880be0875400 ffff880bbf080000 
> > > ffff880bbf08c000 [1248134.772908]  0000000000000000 7fffffffffffffff 
> > > ffff880bbf08bb38 ffffffff816fbb40 [1248134.772911]  ffff880bbf08b9e0 
> > > ffffffff816fb2d5 ffff880c176d6d00 ffff880bbf08ba88 [1248134.772915] Call Trace:
> > > [1248134.772923]  [<ffffffff816fbb40>] ? bit_wait+0x50/0x50 
> > > [1248134.772926]  [<ffffffff816fb2d5>] schedule+0x35/0x80 
> > > [1248134.772929]  [<ffffffff816fdfe7>] schedule_timeout+0x237/0x2d0 
> > > [1248134.772935]  [<ffffffff8161ee0e>] ? ip_output+0x6e/0xe0 
> > > [1248134.772938]  [<ffffffff8161e502>] ? __ip_local_out+0x92/0x110 
> > > [1248134.772941]  [<ffffffff810f303a>] ? ktime_get+0x3a/0x90 
> > > [1248134.772944]  [<ffffffff816fbb40>] ? bit_wait+0x50/0x50 
> > > [1248134.772947]  [<ffffffff816faa46>] io_schedule_timeout+0xa6/0x110 
> > > [1248134.772950]  [<ffffffff816fbb5b>] bit_wait_io+0x1b/0x60 
> > > [1248134.772952]  [<ffffffff816fb8ee>] __wait_on_bit_lock+0x4e/0xb0 
> > > [1248134.772958]  [<ffffffff81189759>] __lock_page+0xb9/0xe0
> >
> > Waiting for a page lock with ILOCK held...
> >
> > > [1248134.772962]  [<ffffffff810c2910>] ? 
> > > autoremove_wake_function+0x40/0x40
> > > [1248134.773007]  [<ffffffffa08d7c70>] 
> > > xfs_find_get_desired_pgoff.isra.10+0x1e0/0x2d0 [xfs] [1248134.773039]  
> > > [<ffffffffa08d7f9d>] xfs_seek_hole_data+0x23d/0x2c0 [xfs] 
> > > [1248134.773054]  [<ffffffffa05d942c>] ? 
> > > nfs4_preprocess_stateid_op+0x11c/0x430 [nfsd] [1248134.773086]  
> > > [<ffffffffa08d803c>] xfs_file_llseek+0x1c/0x40 [xfs] [1248134.773090]  
> > > [<ffffffff8120633e>] vfs_llseek+0x2e/0x30 [1248134.773101]  
> > > [<ffffffffa05c6080>] nfsd4_seek+0x80/0xe0 [nfsd] [1248134.773112]  
> > > [<ffffffffa05c8416>] nfsd4_proc_compound+0x3b6/0x710 [nfsd] 
> > > [1248134.773121]  [<ffffffffa05b4f2e>] nfsd_dispatch+0xce/0x270 [nfsd] 
> > > [1248134.773142]  [<ffffffffa01a5134>] svc_process_common+0x454/0x720 
> > > [sunrpc] [1248134.773151]  [<ffffffffa05b4880>] ? 
> > > nfsd_destroy+0x60/0x60 [nfsd] [1248134.773168]  [<ffffffffa01a5505>] 
> > > svc_process+0x105/0x1c0 [sunrpc] [1248134.773177]  
> > > [<ffffffffa05b4970>] nfsd+0xf0/0x160 [nfsd] [1248134.773180]  
> > > [<ffffffff8109d755>] kthread+0xe5/0x100 [1248134.773183]  
> > > [<ffffffff8109d670>] ? kthread_park+0x60/0x60 [1248134.773187]  
> > > [<ffffffff816ff1cf>] ret_from_fork+0x3f/0x70 [1248134.773190]  
> >  > [<ffffffff8109d670>] ? kthread_park+0x60/0x60 [1248134.773193] 
> > > INFO: task nfsd:1624 blocked for more than 120 seconds.
> > > [1248134.773195]       Tainted: G          I     4.4.73-2.el7.centos.x86_64 #1
> > > [1248134.773197] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> > > [1248134.773198] nfsd            D ffff880bbf1a7738     0  1624      2 0x00000080
> > > [1248134.773202]  ffff880bbf1a7738 ffffffff81a79500 ffff880bbf081500 
> > > ffff880bbf1a8000 [1248134.773205]  ffff8802334477a8 ffff880233447790 
> > > ffffffff00000000 ffffffff00000001 [1248134.773208]  ffff880bbf1a7750 
> > > ffffffff816fb2d5 ffff880bbf081500 ffff880bbf1a77e0 [1248134.773211] Call Trace:
> > > [1248134.773214]  [<ffffffff816fb2d5>] schedule+0x35/0x80 
> > > [1248134.773217]  [<ffffffff816fdab5>] 
> > > rwsem_down_write_failed+0x1f5/0x320
> > > [1248134.773243]  [<ffffffffa089e722>] ? 
> > > xfs_bmap_search_extents+0x72/0xe0 [xfs] [1248134.773273]  
> > > [<ffffffffa08cd212>] ? __xfs_get_blocks+0x162/0x800 [xfs] 
> > > [1248134.773276]  [<ffffffff81346433>] 
> > > call_rwsem_down_write_failed+0x13/0x20
> > > [1248134.773279]  [<ffffffff816fd35d>] ? down_write+0x2d/0x40 
> > > [1248134.773311]  [<ffffffffa08e459a>] xfs_ilock+0xea/0x130 [xfs]
> >
> >...and waiting for the ILOCK with page lock held.
> >
> > This is the known deadlock in SEEK_HOLE/SEEK_DATA; I have patches queued to fix it in 4.13, as soon as the dust settles and I send the pull req.
> 
> Short, precise, frightening.
> 
> Can you advise what will the best option to avoid that error. 
> First things that come to my mind would be:
> 
> - get back to original 3.10 stable kernel from CentOS Distro 
> - lower NFS mount version
> - Maybe remove some single patch that introduced the error?

Unfortunately, SEEK_HOLE (and the deadlocky code) go all the way back to
the beginning of SEEK_HOLE support, so I don't know that there's a good
workaround for this.  There's not really a way to shut off support for
it, either, that doesn't involve gross code surgery.

--D

> 
> Thanks in advance.
> 
> Markus

> ****************************************************************************
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> 
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> Dr. Michael H??hnerbach
> 
> Vorsitzender des Aufsichtsrates:
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> 
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> This e-mail may contain confidential and/or privileged information. If you
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> 
> ****************************************************************************

AW: XFS hang - 4.4.73 longterm

[Markus Stockhausen]

[-- Attachment #1: Type: text/plain, Size: 1578 bytes --]

> -----Ursprüngliche Nachricht-----
> Von: Darrick J. Wong [mailto:darrick.wong@oracle.com] 
> Gesendet: Freitag, 7. Juli 2017 05:47
> An: Markus Stockhausen
> Cc: 'linux-xfs@vger.kernel.org'
> Betreff: Re: XFS hang - 4.4.73 longterm
>
> > > ...
> > > This is the known deadlock in SEEK_HOLE/SEEK_DATA; I have patches queued to fix it in 4.13, as soon as the dust settles and I send the pull req.
> > 
> > Short, precise, frightening.
> > 
> > Can you advise what will the best option to avoid that error. 
> > First things that come to my mind would be:
> > 
> > - get back to original 3.10 stable kernel from CentOS Distro
> > - lower NFS mount version
> > - Maybe remove some single patch that introduced the error?
>
> Unfortunately, SEEK_HOLE (and the deadlocky code) go all the way back to the beginning of SEEK_HOLE support, so I don't know that 
> there's a good workaround for this.  There's not really a way to shut off support for it, either, that doesn't involve gross code surgery.

Not good news. Finally I disabled SEEK support in nfsd by partially reverting 3.18 patch 
24bab491220faa446d94 "NFSD: Implement SEEK". While before NFS/XFS crashed with 
active VM snapshots and heavy disk writes after minutes it now runs for 2 days of 
intensive testing without errors.

At least now I have full discard support in side VMs (via hole punching of disk files).
I'm not familiar with SEEK_HOLE/SEEK_data feature. Do you see negative impact
if disabling these? In contrast to falling back to NFS 4 without seek + discard support.

Markus 

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Dr. Michael Höhnerbach

Vorsitzender des Aufsichtsrates:
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Registergericht: Amtsgericht Köln
Registernummer: HRB 52 497

This e-mail may contain confidential and/or privileged information. If you
are not the intended recipient (or have received this e-mail in error)
please notify the sender immediately and destroy this e-mail. Any
unauthorized copying, disclosure or distribution of the material in this
e-mail is strictly forbidden.

e-mails sent over the internet may have been written under a wrong name or
been manipulated. That is why this message sent as an e-mail is not a
legally binding declaration of intention.

Collogia
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D-50678 Köln

executive board:
Kadir Akin
Dr. Michael Höhnerbach

President of the supervisory board:
Hans Kristian Langva

Registry office: district court Cologne
Register number: HRB 52 497

****************************************************************************

Re: XFS hang - 4.4.73 longterm

[Darrick J. Wong]

On Sun, Jul 09, 2017 at 05:01:25PM +0000, Markus Stockhausen wrote:
> > -----Ursprüngliche Nachricht-----
> > Von: Darrick J. Wong [mailto:darrick.wong@oracle.com] 
> > Gesendet: Freitag, 7. Juli 2017 05:47
> > An: Markus Stockhausen
> > Cc: 'linux-xfs@vger.kernel.org'
> > Betreff: Re: XFS hang - 4.4.73 longterm
> >
> > > > ...
> > > > This is the known deadlock in SEEK_HOLE/SEEK_DATA; I have patches queued to fix it in 4.13, as soon as the dust settles and I send the pull req.
> > > 
> > > Short, precise, frightening.
> > > 
> > > Can you advise what will the best option to avoid that error. 
> > > First things that come to my mind would be:
> > > 
> > > - get back to original 3.10 stable kernel from CentOS Distro
> > > - lower NFS mount version
> > > - Maybe remove some single patch that introduced the error?
> >
> > Unfortunately, SEEK_HOLE (and the deadlocky code) go all the way back to the beginning of SEEK_HOLE support, so I don't know that 
> > there's a good workaround for this.  There's not really a way to shut off support for it, either, that doesn't involve gross code surgery.
> 
> Not good news. Finally I disabled SEEK support in nfsd by partially
> reverting 3.18 patch 24bab491220faa446d94 "NFSD: Implement SEEK".
> While before NFS/XFS crashed with active VM snapshots and heavy disk
> writes after minutes it now runs for 2 days of intensive testing
> without errors.
> 
> At least now I have full discard support in side VMs (via hole
> punching of disk files).

I'd advise you to set an extent size hint to reduce fragmentation, the
same as we tell everyone else. :)

I'd also advise you not to punch too many holes in the VM files because
that increases extent map overhead.  There's also an unfortunate design
problem in the in-memory extent map -- all the extents have to fit in a
single chunk of memory -- and punching a lot of small holes when memory
is tight can lead to allocation failures.

(Even after we fix that problem I'd still advise against punching a lot
of small holes purely due to the overhead that creates.)

> I'm not familiar with SEEK_HOLE/SEEK_data feature. Do you see negative
> impact if disabling these? In contrast to falling back to NFS 4
> without seek + discard support.

Well, whatever program was using SEEK_{HOLE,DATA} to skip sparse holes
in the files will likely revert to a much slower "read the whole file
looking for block aligned zeroes" algorithm... assuming that was why it
was doing that in the first place.

FWIW I just sent off the 4.13 merge request with the SEEK_HOLE fixes,
though they depend on iomap, which (iirc) wasn't added to the vfs until
4.8 or so.

--D

> 
> Markus 

> ****************************************************************************
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> 
> Collogia
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> Dr. Michael H??hnerbach
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> This e-mail may contain confidential and/or privileged information. If you
> are not the intended recipient (or have received this e-mail in error)
> please notify the sender immediately and destroy this e-mail. Any
> unauthorized copying, disclosure or distribution of the material in this
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> 
> e-mails sent over the internet may have been written under a wrong name or
> been manipulated. That is why this message sent as an e-mail is not a
> legally binding declaration of intention.
> 
> Collogia
> Unternehmensberatung AG
> Ubierring 11
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> 
> executive board:
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> Dr. Michael H??hnerbach
> 
> President of the supervisory board:
> Hans Kristian Langva
> 
> Registry office: district court Cologne
> Register number: HRB 52 497
> 
> ****************************************************************************

AW: XFS hang - 4.4.73 longterm

[Markus Stockhausen]

[-- Attachment #1: Type: text/plain, Size: 1444 bytes --]

> Von: Darrick J. Wong [darrick.wong@oracle.com]
> Gesendet: Montag, 10. Juli 2017 18:51
> An: Markus Stockhausen
> Cc: 'linux-xfs@vger.kernel.org'
> Betreff: Re: XFS hang - 4.4.73 longterm
> 
> >On Sun, Jul 09, 2017 at 05:01:25PM +0000, Markus Stockhausen wrote:
> > 
> > ...
> > Not good news. Finally I disabled SEEK support in nfsd by partially
> > reverting 3.18 patch 24bab491220faa446d94 "NFSD: Implement SEEK".
> > While before NFS/XFS crashed with active VM snapshots and heavy disk
> > writes after minutes it now runs for 2 days of intensive testing
> > without errors.
> >
> > At least now I have full discard support in side VMs (via hole
> > punching of disk files).
> 
> I'd advise you to set an extent size hint to reduce fragmentation, the
> same as we tell everyone else. :)

Hehe. Since the days of the memory allocation errors and the need for
periodical drop caches we have an eye on it.

> I'd also advise you not to punch too many holes in the VM files because
> that increases extent map overhead.  There's also an unfortunate design
> problem in the in-memory extent map -- all the extents have to fit in a
> single chunk of memory -- and punching a lot of small holes when memory
> is tight can lead to allocation failures.

Thanks for sharing that info. Do you (XFS developers) plan an overhaul 
of that design or will it be enough to simply add RAM to the storage?

Markus

> ..
.

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