linux-kernel - Re: [PATCH v5 00/14] dm-raid/md/raid: fix v6.7 regressions

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Message-ID: <b969c17d-3330-49c9-fb32-60156325949e@huaweicloud.com>
Date: Sun, 18 Feb 2024 09:24:31 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: Benjamin Marzinski <bmarzins@...hat.com>, Song Liu <song@...nel.org>
Cc: Yu Kuai <yukuai1@...weicloud.com>, mpatocka@...hat.com,
 heinzm@...hat.com, xni@...hat.com, blazej.kucman@...ux.intel.com,
 agk@...hat.com, snitzer@...nel.org, dm-devel@...ts.linux.dev,
 jbrassow@....redhat.com, neilb@...e.de, shli@...com, akpm@...l.org,
 linux-kernel@...r.kernel.org, linux-raid@...r.kernel.org,
 yi.zhang@...wei.com, yangerkun@...wei.com, "yukuai (C)" <yukuai3@...wei.com>
Subject: Re: [PATCH v5 00/14] dm-raid/md/raid: fix v6.7 regressions

Hi,

在 2024/02/16 13:46, Benjamin Marzinski 写道:
> On Thu, Feb 15, 2024 at 02:24:34PM -0800, Song Liu wrote:
>> On Thu, Feb 1, 2024 at 1:30 AM Yu Kuai <yukuai1@...weicloud.com> wrote:
>>>
>> [...]
>>>
>>> [1] https://lore.kernel.org/all/CALTww29QO5kzmN6Vd+jT=-8W5F52tJjHKSgrfUc1Z1ZAeRKHHA@mail.gmail.com/
>>>
>>> Yu Kuai (14):
>>>    md: don't ignore suspended array in md_check_recovery()
>>>    md: don't ignore read-only array in md_check_recovery()
>>>    md: make sure md_do_sync() will set MD_RECOVERY_DONE
>>>    md: don't register sync_thread for reshape directly
>>>    md: don't suspend the array for interrupted reshape
>>>    md: fix missing release of 'active_io' for flush
>>
>> Applied 1/14-5/14 to md-6.8 branch (6/14 was applied earlier).
>>
>> Thanks,
>> Song
> 
> I'm still seeing new failures that I can't reproduce in the 6.6 kernel,
> specifically:
> 
> lvconvert-raid-reshape-stripes-load-reload.sh
> lvconvert-repair-raid.sh
> 
> with lvconvert-raid-reshape-stripes-load-reload.sh Patch 12/14
> ("md/raid456: fix a deadlock for dm-raid456 while io concurrent with
> reshape") is changing a hang to a corruption. The issues is that we
> can't simply fail IO that crosses the reshape position. I assume that
> the correct thing to do is have dm-raid reissue it after the suspend,
> when the reshape can make progress again. Perhaps something like this,
> only less naive (although this patch does make the test pass for me).
> Heinz, any thoughts on this? Otherwise, I'll look into this a little
> more and post a RFC patch.

Does the corruption looks like below?

[12504.959682] BUG bio-296 (Not tainted): Object already free
[12504.960239] 
-----------------------------------------------------------------------------
[12504.960239]
[12504.961209] Allocated in mempool_alloc+0xe8/0x270 age=30 cpu=1 pid=203288
[12504.961905]  kmem_cache_alloc+0x36a/0x3b0
[12504.962324]  mempool_alloc+0xe8/0x270
[12504.962712]  bio_alloc_bioset+0x3b5/0x920
[12504.963129]  bio_alloc_clone+0x3e/0x160
[12504.963533]  alloc_io+0x3d/0x1f0
[12504.963876]  dm_submit_bio+0x12f/0xa30
[12504.964267]  __submit_bio+0x9c/0xe0
[12504.964639]  submit_bio_noacct_nocheck+0x25a/0x570
[12504.965136]  submit_bio_wait+0xc2/0x160
[12504.965535]  blkdev_issue_zeroout+0x19b/0x2e0
[12504.965991]  ext4_init_inode_table+0x246/0x560
[12504.966462]  ext4_lazyinit_thread+0x750/0xbe0
[12504.966922]  kthread+0x1b4/0x1f0

I assum that this is a dm problem and I'm still trying to debug it.
Can you explain more why IO that crosses the reshape position can't
fail directly?

Thanks,
Kuai

> 
> =========================================================
> diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
> index ed8c28952b14..ff481d494b04 100644
> --- a/drivers/md/dm-raid.c
> +++ b/drivers/md/dm-raid.c
> @@ -3345,6 +3345,14 @@ static int raid_map(struct dm_target *ti, struct bio *bio)
>   	return DM_MAPIO_SUBMITTED;
>   }
>   
> +static int raid_end_io(struct dm_target *ti, struct bio *bio,
> +		       blk_status_t *error)
> +{
> +	if (*error != BLK_STS_IOERR || !dm_noflush_suspending(ti))
> +		return DM_ENDIO_DONE;
> +	return DM_ENDIO_REQUEUE;
> +}

> +
>   /* Return sync state string for @state */
>   enum sync_state { st_frozen, st_reshape, st_resync, st_check, st_repair, st_recover, st_idle };
>   static const char *sync_str(enum sync_state state)
> @@ -4100,6 +4108,7 @@ static struct target_type raid_target = {
>   	.ctr = raid_ctr,
>   	.dtr = raid_dtr,
>   	.map = raid_map,
> +	.end_io = raid_end_io,
>   	.status = raid_status,
>   	.message = raid_message,
>   	.iterate_devices = raid_iterate_devices,
> =========================================================
>>
>>
>>>    md: export helpers to stop sync_thread
>>>    md: export helper md_is_rdwr()
>>>    dm-raid: really frozen sync_thread during suspend
>>>    md/dm-raid: don't call md_reap_sync_thread() directly
>>>    dm-raid: add a new helper prepare_suspend() in md_personality
>>>    md/raid456: fix a deadlock for dm-raid456 while io concurrent with
>>>      reshape
>>>    dm-raid: fix lockdep waring in "pers->hot_add_disk"
>>>    dm-raid: remove mddev_suspend/resume()
>>>
>>>   drivers/md/dm-raid.c |  78 +++++++++++++++++++--------
>>>   drivers/md/md.c      | 126 +++++++++++++++++++++++++++++--------------
>>>   drivers/md/md.h      |  16 ++++++
>>>   drivers/md/raid10.c  |  16 +-----
>>>   drivers/md/raid5.c   |  61 +++++++++++----------
>>>   5 files changed, 192 insertions(+), 105 deletions(-)
>>>
>>> --
>>> 2.39.2
>>>
>>>
> 
> .
>