From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To: qemu-devel <qemu-devel@nongnu.org>, qemu block <qemu-block@nongnu.org>
Cc: Jeff Cody <jcody@redhat.com>, John Snow <jsnow@redhat.com>,
Fam Zheng <famz@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
"Denis V. Lunev" <den@openvz.org>
Subject: [Qemu-devel] backup notifier fail policy
Date: Fri, 30 Sep 2016 20:11:00 +0300 [thread overview]
Message-ID: <57EE9CA4.6010801@virtuozzo.com> (raw)
Hi all!
Please, can somebody explain me, why we fail guest request in case of io
error in write notifier? I think guest consistency is more important
than success of unfinished backup. Or, what am I missing?
I'm saying about this code:
static int coroutine_fn backup_before_write_notify(
NotifierWithReturn *notifier,
void *opaque)
{
BackupBlockJob *job = container_of(notifier, BackupBlockJob,
before_write);
BdrvTrackedRequest *req = opaque;
int64_t sector_num = req->offset >> BDRV_SECTOR_BITS;
int nb_sectors = req->bytes >> BDRV_SECTOR_BITS;
assert(req->bs == blk_bs(job->common.blk));
assert((req->offset & (BDRV_SECTOR_SIZE - 1)) == 0);
assert((req->bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
return backup_do_cow(job, sector_num, nb_sectors, NULL, true);
}
So, what about something like
ret = backup_do_cow(job, ...
if (ret < 0 && job->notif_ret == 0) {
job->notif_ret = ret;
}
return 0;
and fail block job if notif_ret < 0 in other places of backup code?
--
Best regards,
Vladimir
next reply other threads:[~2016-09-30 17:11 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-30 17:11 Vladimir Sementsov-Ogievskiy [this message]
2016-09-30 18:59 ` [Qemu-devel] backup notifier fail policy Vladimir Sementsov-Ogievskiy
2016-10-03 13:11 ` Stefan Hajnoczi
2016-10-03 18:07 ` John Snow
2016-10-04 9:23 ` Stefan Hajnoczi
2016-10-04 9:34 ` Kevin Wolf
2016-10-04 10:41 ` Denis V. Lunev
2016-10-04 11:55 ` Kevin Wolf
2016-10-04 16:02 ` Stefan Hajnoczi
2016-10-04 16:03 ` John Snow
2016-10-04 16:19 ` Denis V. Lunev
2016-10-05 8:12 ` Kevin Wolf
2016-10-05 12:59 ` Stefan Hajnoczi
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