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From: Ed Swierk <eswierk@skyportsystems.com>
To: Eric Blake <eblake@redhat.com>
Cc: qemu-block@nongnu.org, qemu-devel@nongnu.org,
	Kevin Wolf <kwolf@redhat.com>, "Denis V. Lunev" <den@openvz.org>
Subject: Re: [Qemu-devel] Assertion failure on qcow2 disk with cluster_size != 64k
Date: Fri, 21 Oct 2016 06:14:18 -0700	[thread overview]
Message-ID: <CAO_EM_kcuXpy-B--QD+-i3co7_1Ku+3j=AAA0a94t2vkXfkcUg@mail.gmail.com> (raw)
In-Reply-To: <8b945cd9-a601-4c81-495f-c1837f8d8231@redhat.com>

On Thu, Oct 20, 2016 at 6:38 PM, Eric Blake <eblake@redhat.com> wrote:
> On 10/20/2016 07:24 PM, Ed Swierk wrote:
>> Changing max_transfer in the normal write case to
>> MIN_NON_ZERO(alignment, MAX_WRITE_ZEROES_BOUNCE_BUFFER) appears to fix
>> the problem, but I don't pretend to understand all the subtleties
>> here.
>
> That actually sounds like the right fix.  But since the bug was probably
> caused by my code, I'll formalize it into a patch and see if I can
> modify the testsuite to give it coverage.

If alignment > MAX_WRITE_ZEROES_BOUNCE_BUFFER (however unlikely) we
have the same problem, so maybe this would be better?

max_transfer = alignment > 0 ? alignment : MAX_WRITE_ZEROES_BOUNCE_BUFFER

--Ed

  reply	other threads:[~2016-10-21 13:15 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-21  0:24 [Qemu-devel] Assertion failure on qcow2 disk with cluster_size != 64k Ed Swierk
2016-10-21  1:38 ` Eric Blake
2016-10-21 13:14   ` Ed Swierk [this message]
2016-10-24 20:32     ` Eric Blake
2016-11-14  9:50       ` Kevin Wolf
2016-11-14 15:46         ` Eric Blake
2016-11-14 15:54           ` Kevin Wolf
2016-11-14 16:59             ` Eric Blake
2016-10-24 21:21 ` Eric Blake
2016-10-24 23:06   ` Ed Swierk
2016-10-25  8:39     ` Kevin Wolf
2016-10-25 13:51       ` Eric Blake

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