From: Yu Kuai <yukuai1@huaweicloud.com>
To: Sergei Shtepa <sergei.shtepa@veeam.com>,
Yu Kuai <yukuai1@huaweicloud.com>,
axboe@kernel.dk, hch@infradead.org, corbet@lwn.net,
snitzer@kernel.org
Cc: viro@zeniv.linux.org.uk, brauner@kernel.org, dchinner@redhat.com,
willy@infradead.org, dlemoal@kernel.org, linux@weissschuh.net,
jack@suse.cz, ming.lei@redhat.com, linux-block@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org,
Donald Buczek <buczek@molgen.mpg.de>,
"yukuai (C)" <yukuai3@huawei.com>
Subject: Re: [PATCH v5 02/11] block: Block Device Filtering Mechanism
Date: Tue, 18 Jul 2023 09:37:33 +0800 [thread overview]
Message-ID: <d929eaa7-61d6-c4c4-aabc-0124c3693e10@huaweicloud.com> (raw)
In-Reply-To: <90f79cf3-86a2-02c0-1887-d3490f9848bb@veeam.com>
Hi,
在 2023/07/17 22:39, Sergei Shtepa 写道:
>
>
> On 7/11/23 04:02, Yu Kuai wrote:
>> bdev_disk_changed() is not handled, where delete_partition() and
>> add_partition() will be called, this means blkfilter for partiton will
>> be removed after partition rescan. Am I missing something?
>
> Yes, when the bdev_disk_changed() is called, all disk block devices
> are deleted and new ones are re-created. Therefore, the information
> about the attached filters will be lost. This is equivalent to
> removing the disk and adding it back.
>
> For the blksnap module, partition rescan will mean the loss of the
> change trackers data. If a snapshot was created, then such
> a partition rescan will cause the snapshot to be corrupted.
>
I haven't review blksnap code yet, but this sounds like a problem.
possible solutions I have in mind:
1. Store blkfilter for each partition from bdev_disk_changed() before
delete_partition(), and add blkfilter back after add_partition().
2. Store blkfilter from gendisk as a xarray, and protect it by
'open_mutex' like 'part_tbl', block_device can keep the pointer to
reference blkfilter so that performance from fast path is ok, and the
lifetime of blkfiter can be managed separately.
> There was an idea to do filtering at the disk level,
> but I abandoned it.
> .
>
I think it's better to do filtering at the partition level as well.
Thanks,
Kuai
next prev parent reply other threads:[~2023-07-18 1:37 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-12 13:52 [PATCH v5 00/11] blksnap - block devices snapshots module Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 01/11] documentation: Block Device Filtering Mechanism Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 02/11] block: " Sergei Shtepa
2023-07-11 2:02 ` Yu Kuai
2023-07-12 10:04 ` Yu Kuai
2023-07-12 12:34 ` Yu Kuai
2023-07-17 17:39 ` Sergei Shtepa
2023-07-18 1:21 ` Yu Kuai
2023-07-17 16:22 ` Sergei Shtepa
2023-07-17 14:39 ` Sergei Shtepa
2023-07-18 1:37 ` Yu Kuai [this message]
2023-07-18 11:25 ` Sergei Shtepa
2023-07-18 12:32 ` Yu Kuai
2023-07-18 16:33 ` Sergei Shtepa
2023-07-19 7:28 ` Yu Kuai
2023-07-19 8:36 ` Sergei Shtepa
2023-07-20 6:14 ` Christoph Hellwig
2023-06-12 13:52 ` [PATCH v5 03/11] documentation: Block Devices Snapshots Module Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 04/11] blksnap: header file of the module interface Sergei Shtepa
2023-06-13 22:25 ` Dave Chinner
2023-06-14 6:26 ` Christoph Hellwig
2023-06-14 9:26 ` Sergei Shtepa
2023-06-14 14:07 ` Christoph Hellwig
2023-06-14 16:43 ` Sergei Shtepa
2023-06-15 0:08 ` Dave Chinner
2023-07-17 18:57 ` Thomas Weißschuh
2023-07-18 9:53 ` Sergei Shtepa
2023-07-20 6:16 ` Christoph Hellwig
2023-06-12 13:52 ` [PATCH v5 05/11] blksnap: module management interface functions Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 06/11] blksnap: handling and tracking I/O units Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 07/11] blksnap: minimum data storage unit of the original block device Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 08/11] blksnap: difference storage Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 09/11] blksnap: event queue from the " Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 10/11] blksnap: snapshot and snapshot image block device Sergei Shtepa
2023-06-12 13:52 ` [PATCH v5 11/11] blksnap: Kconfig and Makefile Sergei Shtepa
2023-06-12 14:32 ` [PATCH v5 00/11] blksnap - block devices snapshots module Christoph Hellwig
2023-06-12 16:19 ` Eric Biggers
2023-06-13 5:50 ` Christoph Hellwig
2023-06-13 10:12 ` Sergei Shtepa
2023-06-14 17:22 ` Eric Biggers
-- strict thread matches above, loose matches on Subject: below --
2023-06-12 13:21 Sergei Shtepa
2023-06-12 13:21 ` [PATCH v5 02/11] block: Block Device Filtering Mechanism Sergei Shtepa
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