Re: Backport of "xfs: open code ioend needs workqueue helper" to 5.10?

[Chandan Babu R <chandan.babu@oracle.com>]

On Thu, Apr 13, 2023 at 10:44:43 AM +0300, Amir Goldstein wrote:
> On Wed, Apr 12, 2023 at 6:58 PM Christian Theune <ct@flyingcircus.io> wrote:
>>
>> Hi,
>>
>> ugh. Sorry, looks like I jumped the gun. Mea culpa.
>>
>> We experienced a hang like this:
>>
>> Apr 05 11:51:27 kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> Apr 05 11:51:27 kernel: task:xfs-conv/vdc1   state:D stack:    0 pid:  606 ppid:     2 flags:0x00004080
>> Apr 05 11:51:27 kernel: Workqueue: xfs-conv/vdc1 xfs_end_io [xfs]
>> Apr 05 11:51:27 kernel: Call Trace:
>> Apr 05 11:51:27 kernel:  __schedule+0x274/0x870
>> Apr 05 11:51:27 kernel:  schedule+0x46/0xb0
>> Apr 05 11:51:27 kernel:  xlog_grant_head_wait+0xc5/0x1d0 [xfs]
>> Apr 05 11:51:27 kernel:  xlog_grant_head_check+0xde/0x100 [xfs]
>> Apr 05 11:51:27 kernel:  xfs_log_reserve+0xbe/0x1b0 [xfs]
>> Apr 05 11:51:27 kernel:  xfs_trans_reserve+0x143/0x180 [xfs]
>> Apr 05 11:51:27 kernel:  xfs_trans_alloc+0xee/0x1a0 [xfs]
>> Apr 05 11:51:27 kernel:  xfs_iomap_write_unwritten+0x120/0x2e0 [xfs]
>> Apr 05 11:51:27 kernel:  ? record_times+0x15/0x90
>> Apr 05 11:51:27 kernel:  xfs_end_ioend+0xd8/0x140 [xfs]
>> Apr 05 11:51:27 kernel:  xfs_end_io+0xb8/0xf0 [xfs]
>> Apr 05 11:51:27 kernel:  process_one_work+0x1b6/0x350
>> Apr 05 11:51:27 kernel:  rescuer_thread+0x1d1/0x3a0
>> Apr 05 11:51:27 kernel:  ? worker_thread+0x3e0/0x3e0
>> Apr 05 11:51:27 kernel:  kthread+0x11b/0x140
>> Apr 05 11:51:27 kernel:  ? kthread_associate_blkcg+0xb0/0xb0
>> Apr 05 11:51:27 kernel:  ret_from_fork+0x22/0x30
>>
>> Which seems to be similar to this:
>> https://bugs.launchpad.net/bugs/1996269
>>
>> I followed their patchset here:
>> https://review.opendev.org/c/starlingx/kernel/+/864257
>>
>> And I was under the impression that I picked the right one to ask
>> for backporting, but it seems that was incorrect. I went through the
>> list again and I think the following patches are the ones missing
>> from 5.10:
>>
>> 8182ec00803085354761bbadf0287cad7eac0e2f -
>> https://review.opendev.org/c/starlingx/kernel/+/864257/5/kernel-std/centos/patches/0035-xfs-drop-submit-side-trans-alloc-for-append-ioends.patch
>> edbf1eb9032b84631031d9b43570e262f3461c24 -
>> https://review.opendev.org/c/starlingx/kernel/+/864257/5/kernel-std/centos/patches/0036-xfs-open-code-ioend-needs-workqueue-helper.patch
>> 170e31793806ce5e5a9647b6340954536244518e -
>> https://review.opendev.org/c/starlingx/kernel/+/864257/5/kernel-std/centos/patches/0037-xfs-drop-unused-ioend-private-merge-and-setfilesize-.patch
>> 2fd609b6c90a88630a50fb317473b210759b3873 -
>> https://review.opendev.org/c/starlingx/kernel/+/864257/5/kernel-std/centos/patches/0038-xfs-drop-unnecessary-setfilesize-helper.patch
>>
>
> The only commit that fixes the bug is:
> 7cd3099f4925 xfs: drop submit side trans alloc for append ioends
>
> The rest are just code cleanups.
>
> That fix was missed in my original backports from v5.13 because of a tool error,
> so thank you for pointing it out.
>
> I have added it to my test branch and will follow up with posting to
> stable later on.
>
> Chandan,
>
> Please make sure you include this fix when you get to considering
> fixes from v5.13 to 5.4.y.
>

Sure, I will do that. However ...

> I will wait with posting this fix to 5.10.y until I get the v5.13
> backports wish list from you.
>

Since I am working on another XFS work item there will be some delay before I
share the list of patches to be backported from v5.13 to 5.4.y.

-- 
chandan