From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41968) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZswmN-0001fl-Bx for qemu-devel@nongnu.org; Sun, 01 Nov 2015 12:50:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZswmK-0003AE-4E for qemu-devel@nongnu.org; Sun, 01 Nov 2015 12:50:55 -0500 Received: from relay.parallels.com ([195.214.232.42]:40604) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZswmJ-0003A5-SE for qemu-devel@nongnu.org; Sun, 01 Nov 2015 12:50:52 -0500 References: <1446220661-18792-1-git-send-email-stefanha@redhat.com> From: "Denis V. Lunev" Message-ID: <563650EC.2040307@openvz.org> Date: Sun, 1 Nov 2015 20:50:36 +0300 MIME-Version: 1.0 In-Reply-To: <1446220661-18792-1-git-send-email-stefanha@redhat.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] blockdev: acquire AioContext in hmp_commit() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi , qemu-devel@nongnu.org Cc: Kevin Wolf , Markus Armbruster , qemu-block@nongnu.org On 10/30/2015 06:57 PM, Stefan Hajnoczi wrote: > This one slipped through. Although we acquire AioContext when > committing all devices we don't for just a single device. > > AioContext must be acquired before calling bdrv_*() functions to > synchronize access with other threads that may be using the AioContext. > > Signed-off-by: Stefan Hajnoczi > --- > blockdev.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/blockdev.c b/blockdev.c > index 18712d2..d611779 100644 > --- a/blockdev.c > +++ b/blockdev.c > @@ -1120,6 +1120,9 @@ void hmp_commit(Monitor *mon, const QDict *qdict) > if (!strcmp(device, "all")) { > ret = bdrv_commit_all(); > } else { > + BlockDriverState *bs; > + AioContext *aio_context; > + > blk = blk_by_name(device); > if (!blk) { > monitor_printf(mon, "Device '%s' not found\n", device); > @@ -1129,7 +1132,14 @@ void hmp_commit(Monitor *mon, const QDict *qdict) > monitor_printf(mon, "Device '%s' has no medium\n", device); > return; > } > - ret = bdrv_commit(blk_bs(blk)); > + > + bs = blk_bs(blk); > + aio_context = bdrv_get_aio_context(bs); > + aio_context_acquire(aio_context); > + > + ret = bdrv_commit(bs); > + > + aio_context_release(aio_context); > } > if (ret < 0) { > monitor_printf(mon, "'commit' error for '%s': %s\n", device, I like it in general, but could you pls wait a bit before pushing it up. I am working at the moment on a more generic series. I am going to attach this patch to it to consider the situation as a whole. It would be much trickier than my previous one. There are several other places discovered. Den