From: Konstantin Khorenko <khorenko@virtuozzo.com>
To: Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com>
Cc: devel@openvz.org
Subject: Re: [Devel] [PATCH hci-8.1 1/7] drivers/md/dm-qcow2: repeat md page lookup if it was inserted in parallel
Date: Wed, 04 Nov 2026 22:35:09 +0100 [thread overview]
Message-ID: <179382810903.2794215.912454250560308768.b4-review@b4> (raw)
In-Reply-To: <20261029140346.465768-2-andrey.zhadchenko@virtuozzo.com>
I won't apply this version, please send v2 with the changes below.
On Thu, 29 Oct 2026 17:03:40 +0300, Andrey Zhadchenko wrote:
> teach __handle_md_page() to work around -EEXIST by retrying.
Item 3 of the cover letter reply: say in the message what fails
without this patch, and add a Fixes tag for 412d5a4f7bf1b
("dm/dm-qcow2: add llseek_hole").
Why: the race is already there. qcow2_llseek_hole() runs
parse_metadata() in process context, in parallel with the main kwork.
When both miss the same md page, the one that loses the insert gets
-EEXIST: a guest I/O ends with EIO, or lseek returns -EEXIST. So this
is a fix on its own, not only a preparation for the fast path.
--
Konstantin Khorenko,
Virtuozzo Linux Kernel Team
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next prev parent reply other threads:[~2026-11-04 21:36 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-29 14:03 [Devel] [PATCH 0/7] drivers/md/dm-qcow2: per-qio fast path Andrey Zhadchenko
2026-10-29 14:03 ` [Devel] [PATCH hci-8.1 1/7] drivers/md/dm-qcow2: repeat md page lookup if it was inserted in parallel Andrey Zhadchenko
2026-10-29 14:13 ` no-reply
2026-11-04 21:35 ` Konstantin Khorenko [this message]
2026-10-29 14:03 ` [Devel] [PATCH hci-8.1 2/7] drivers/md/dm-qcow2: check MD_DIRTY and md->wbd under lock in perform_rw_mapped() Andrey Zhadchenko
2026-10-29 14:13 ` no-reply
2026-11-04 21:35 ` Konstantin Khorenko
2026-10-29 14:03 ` [Devel] [PATCH hci-8.1 3/7] drivers/md/dm-qcow2: prepare process_one_qio() for fastpath Andrey Zhadchenko
2026-10-29 14:16 ` no-reply
2026-11-02 17:28 ` Alexander Ivanov
2026-11-04 21:35 ` Konstantin Khorenko
2026-10-29 14:03 ` [Devel] [PATCH hci-8.1 4/7] drivers/md/dm-qcow2: add per-qio work infrastructure Andrey Zhadchenko
2026-10-29 14:18 ` no-reply
2026-11-04 21:35 ` Konstantin Khorenko
2026-10-29 14:03 ` [Devel] [PATCH hci-8.1 5/7] drivers/md/dm-qcow2: implement per-qio fast processing Andrey Zhadchenko
2026-10-29 14:22 ` no-reply
2026-11-04 21:35 ` Konstantin Khorenko
2026-10-29 14:03 ` [Devel] [PATCH hci-8.1 6/7] drivers/md/dm-qcow2: declare DM_TARGET_NOWAIT Andrey Zhadchenko
2026-10-29 14:19 ` no-reply
2026-11-03 8:33 ` Alexander Ivanov
2026-11-04 21:35 ` Konstantin Khorenko
2026-10-29 14:03 ` [Devel] [PATCH hci-8.1 7/7] drivers/md/dm-qcow2: process fast path qios in per-cpu batches on a workqueue Andrey Zhadchenko
2026-10-29 14:22 ` no-reply
2026-11-02 10:49 ` Andrey Zhadchenko
2026-11-04 21:35 ` Konstantin Khorenko
2026-11-03 9:36 ` [Devel] [PATCH 0/7] drivers/md/dm-qcow2: per-qio fast path Alexander Ivanov
2026-11-04 21:35 ` Konstantin Khorenko
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