From: Guenter Roeck <linux@roeck-us.net>
To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, dm-devel@redhat.com,
Mike Snitzer <snitzer@redhat.com>
Subject: Re: [dm-devel] [PATCH 4/8] block: support delayed holder registration
Date: Sun, 15 Aug 2021 07:27:37 -0700 [thread overview]
Message-ID: <a8d66952-ee44-d3fa-d699-439415b9abfe@roeck-us.net> (raw)
In-Reply-To: <20210815070724.GA23276@lst.de>
On 8/15/21 12:07 AM, Christoph Hellwig wrote:
> On Sat, Aug 14, 2021 at 02:13:09PM -0700, Guenter Roeck wrote:
>> On Wed, Aug 04, 2021 at 11:41:43AM +0200, Christoph Hellwig wrote:
>>> device mapper needs to register holders before it is ready to do I/O.
>>> Currently it does so by registering the disk early, which can leave
>>> the disk and queue in a weird half state where the queue is registered
>>> with the disk, except for sysfs and the elevator. And this state has
>>> been a bit promlematic before, and will get more so when sorting out
>>> the responsibilities between the queue and the disk.
>>>
>>> Support registering holders on an initialized but not registered disk
>>> instead by delaying the sysfs registration until the disk is registered.
>>>
>>> Signed-off-by: Christoph Hellwig <hch@lst.de>
>>> Reviewed-by: Mike Snitzer <snitzer@redhat.com>
>>
>> This patch results in lockdep splats when booting from flash.
>> Reverting it fixes the proboem.
>
> Should be fixed by:
> https://git.kernel.dk/cgit/linux-block/commit/?h=for-5.15/drivers&id=6e4df4c6488165637b95b9701cc862a42a3836ba
>
No, it doesn't. I could not apply this patch alone, so I applied the entire series
on top of next-20210813 and gave it another try.
f53c2d11ac98 (HEAD -> master) nbd: reduce the nbd_index_mutex scope
f2f5254b356f nbd: refactor device search and allocation in nbd_genl_connect
d5b03177e069 nbd: return the allocated nbd_device from nbd_dev_add
350b3f6a6e6b nbd: remove nbd_del_disk
49efbeb9de86 nbd: refactor device removal
cdd920eb7cf2 nbd: do del_gendisk() asynchronously for NBD_DESTROY_ON_DISCONNECT
4b358aabb93a (tag: next-20210813, origin/master, origin/HEAD) Add linux-next specific files for 20210813
Still:
...
[ 14.467748][ T1] Possible unsafe locking scenario:
[ 14.467748][ T1]
[ 14.467928][ T1] CPU0 CPU1
[ 14.468058][ T1] ---- ----
[ 14.468187][ T1] lock(&disk->open_mutex);
[ 14.468317][ T1] lock(mtd_table_mutex);
[ 14.468493][ T1] lock(&disk->open_mutex);
[ 14.468671][ T1] lock(mtd_table_mutex);
Guenter
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next prev parent reply other threads:[~2021-08-15 14:28 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-04 9:41 [dm-devel] use regular gendisk registration in device mapper v2 Christoph Hellwig
2021-08-04 9:41 ` [dm-devel] [PATCH 1/8] block: make the block holder code optional Christoph Hellwig
2021-08-04 9:41 ` [dm-devel] [PATCH 2/8] block: remove the extra kobject reference in bd_link_disk_holder Christoph Hellwig
2021-08-04 9:41 ` [dm-devel] [PATCH 3/8] block: look up holders by bdev Christoph Hellwig
2021-08-04 9:41 ` [dm-devel] [PATCH 4/8] block: support delayed holder registration Christoph Hellwig
[not found] ` <CGME20210810213058eucas1p109323e3c3ecaa76d37d8cf63b6d8ecfd@eucas1p1.samsung.com>
2021-08-10 21:30 ` Marek Szyprowski
2021-08-14 21:13 ` Guenter Roeck
2021-08-15 7:07 ` Christoph Hellwig
2021-08-15 14:27 ` Guenter Roeck [this message]
2021-08-16 7:21 ` Christoph Hellwig
2021-08-16 14:17 ` Guenter Roeck
2021-08-20 15:08 ` Christoph Hellwig
2021-08-21 3:17 ` Guenter Roeck
2021-08-18 2:51 ` Guenter Roeck
2021-08-04 9:41 ` [dm-devel] [PATCH 5/8] dm: cleanup cleanup_mapped_device Christoph Hellwig
2021-08-04 9:41 ` [dm-devel] [PATCH 6/8] dm: move setting md->type into dm_setup_md_queue Christoph Hellwig
2021-08-04 9:41 ` [dm-devel] [PATCH 7/8] dm: delay registering the gendisk Christoph Hellwig
2021-08-09 23:31 ` Alasdair G Kergon
2021-08-10 0:17 ` Alasdair G Kergon
2021-08-10 13:12 ` Peter Rajnoha
2021-08-10 15:05 ` Alasdair G Kergon
2022-07-07 3:29 ` Yu Kuai
2022-07-07 5:24 ` Christoph Hellwig
2022-07-07 7:20 ` Yu Kuai
2022-07-15 3:24 ` Yu Kuai
2022-08-01 1:04 ` Yu Kuai
2021-08-04 9:41 ` [dm-devel] [PATCH 8/8] block: remove support for delayed queue registrations Christoph Hellwig
2021-08-09 17:51 ` [dm-devel] use regular gendisk registration in device mapper v2 Jens Axboe
2021-08-10 0:36 ` Alasdair G Kergon
2021-08-10 14:41 ` Alasdair G Kergon
2021-08-19 15:58 ` [dm-devel] holders not working properly, regression [was: Re: use regular gendisk registration in device mapper v2] Mike Snitzer
2021-08-19 18:05 ` Christoph Hellwig
2021-08-19 22:08 ` Mike Snitzer
-- strict thread matches above, loose matches on Subject: below --
2021-07-25 5:54 [dm-devel] use regular gendisk registration in device mapper Christoph Hellwig
2021-07-25 5:54 ` [dm-devel] [PATCH 4/8] block: support delayed holder registration Christoph Hellwig
2021-07-27 16:06 ` Mike Snitzer
2021-07-28 6:54 ` Christoph Hellwig
2021-07-29 16:32 ` Mike Snitzer
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