From: Jeff Cody <jcody@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
qemu-devel@nongnu.org, qemu-block@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] block/mirror: limit qiov to IOV_MAX elements
Date: Thu, 6 Aug 2015 04:50:17 -0400 [thread overview]
Message-ID: <20150806085017.GE9878@localhost.localdomain> (raw)
In-Reply-To: <1435761950-26714-1-git-send-email-stefanha@redhat.com>
On Wed, Jul 01, 2015 at 03:45:50PM +0100, Stefan Hajnoczi wrote:
> If mirror has more free buffers than IOV_MAX, preadv(2)/pwritev(2)
> EINVAL failures may be encountered.
>
> It is possible to trigger this by setting granularity to a low value
> like 8192.
>
> This patch stops appending chunks once IOV_MAX is reached.
>
> The spurious EINVAL failure can be reproduced with a qcow2 image file
> and the following QMP invocation:
>
> qmp.command('drive-mirror', device='virtio0', target='/tmp/r7.s1',
> granularity=8192, sync='full', mode='absolute-paths',
> format='raw')
>
> While the guest is running dd if=/dev/zero of=/var/tmp/foo oflag=direct
> bs=4k.
>
Thanks,
Applied to my 'block-next' branch:
https://github.com/codyprime/qemu-kvm-jtc/tree/block-next
-Jeff
prev parent reply other threads:[~2015-08-06 8:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-01 14:45 [Qemu-devel] [PATCH] block/mirror: limit qiov to IOV_MAX elements Stefan Hajnoczi
2015-07-01 14:47 ` Paolo Bonzini
2015-07-01 14:59 ` [Qemu-devel] [Qemu-block] " Stefan Hajnoczi
2015-07-01 15:03 ` Paolo Bonzini
2015-07-01 16:05 ` Stefan Hajnoczi
2015-07-08 11:14 ` Kevin Wolf
2015-07-08 12:34 ` Stefan Hajnoczi
2015-08-04 16:13 ` Stefan Hajnoczi
2015-08-06 8:50 ` Jeff Cody [this message]
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