From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:45434) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gwBVi-0006V0-HP for qemu-devel@nongnu.org; Tue, 19 Feb 2019 14:56:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gwBVS-0007mA-5K for qemu-devel@nongnu.org; Tue, 19 Feb 2019 14:56:48 -0500 References: <20190218233154.19303-1-jsnow@redhat.com> <3374bbeb-cc15-acbb-88d8-a057bbfe5482@redhat.com> From: John Snow Message-ID: <6fa2dcc8-3cd4-527e-e085-49bfc364dcf8@redhat.com> Date: Tue, 19 Feb 2019 14:56:32 -0500 MIME-Version: 1.0 In-Reply-To: <3374bbeb-cc15-acbb-88d8-a057bbfe5482@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v5] blockdev: acquire aio_context for bitmap add/remove List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake , qemu-devel@nongnu.org, qemu-block@nongnu.org Cc: Kevin Wolf , pbonzini@redhat.com, vsementsov@virtuozzo.com, Markus Armbruster , Max Reitz On 2/19/19 9:59 AM, Eric Blake wrote: > On 2/18/19 5:31 PM, John Snow wrote: >> When bitmaps are persistent, they may incur a disk read or write when bitmaps >> are added or removed. For configurations like virtio-dataplane, failing to >> acquire this lock will abort QEMU when disk IO occurs. >> >> We used to acquire aio_context as part of the bitmap lookup, so re-introduce >> the lock for just the cases that have an IO penalty. Commit 2119882c removed >> these locks, and I failed to notice this when we committed fd5ae4cc, so this >> has been broken since persistent bitmaps were introduced. >> >> Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1672010 >> Reported-By: Aihua Liang >> Signed-off-by: John Snow >> --- >> v5: I'm having a really bad day. This version actually has the semicolon. >> --- >> blockdev.c | 26 ++++++++++++++++++++------ >> 1 file changed, 20 insertions(+), 6 deletions(-) > > Reviewed-by: Eric Blake > > and yes, this time it builds. > I am really very sorry for the noise on this simple series. Thank you for the review and your patience. --John