From patchwork Thu Nov 22 10:00:19 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Priebe - Profihost AG X-Patchwork-Id: 1785461 Return-Path: X-Original-To: patchwork-ceph-devel@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 2E88EDF24C for ; Thu, 22 Nov 2012 19:01:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755512Ab2KVTAe (ORCPT ); Thu, 22 Nov 2012 14:00:34 -0500 Received: from packetbuilder64bit.de-nserver.de ([85.158.179.228]:60052 "EHLO packetbuilder64bit.de-nserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753895Ab2KVTAY (ORCPT ); Thu, 22 Nov 2012 14:00:24 -0500 Received: (qmail 5516 invoked by uid 0); 22 Nov 2012 11:00:21 +0100 From: Stefan Priebe To: qemu-devel@nongnu.org Cc: stefanha@gmail.com, josh.durgin@inktank.com, ceph-devel@vger.kernel.org, pbonzini@redhat.com, Stefan Priebe Subject: [PATCH] rbd block driver fix race between aio completition and aio cancel Date: Thu, 22 Nov 2012 11:00:19 +0100 Message-Id: <1353578419-5481-1-git-send-email-s.priebe@profihost.ag> X-Mailer: git-send-email 1.7.10.4 Sender: ceph-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org This one fixes a race which qemu had also in iscsi block driver between cancellation and io completition. qemu_rbd_aio_cancel was not synchronously waiting for the end of the command. To archieve this it introduces a new status flag which uses -EINPROGRESS. Signed-off-by: Stefan Priebe --- block/rbd.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/block/rbd.c b/block/rbd.c index 0384c6c..783c3d7 100644 --- a/block/rbd.c +++ b/block/rbd.c @@ -77,6 +77,7 @@ typedef struct RBDAIOCB { int error; struct BDRVRBDState *s; int cancelled; + int status; } RBDAIOCB; typedef struct RADOSCB { @@ -376,12 +377,6 @@ static void qemu_rbd_complete_aio(RADOSCB *rcb) RBDAIOCB *acb = rcb->acb; int64_t r; - if (acb->cancelled) { - qemu_vfree(acb->bounce); - qemu_aio_release(acb); - goto done; - } - r = rcb->ret; if (acb->cmd == RBD_AIO_WRITE || @@ -406,10 +401,11 @@ static void qemu_rbd_complete_aio(RADOSCB *rcb) acb->ret = r; } } + acb->status = 0; + /* Note that acb->bh can be NULL in case where the aio was cancelled */ acb->bh = qemu_bh_new(rbd_aio_bh_cb, acb); qemu_bh_schedule(acb->bh); -done: g_free(rcb); } @@ -574,6 +570,12 @@ static void qemu_rbd_aio_cancel(BlockDriverAIOCB *blockacb) { RBDAIOCB *acb = (RBDAIOCB *) blockacb; acb->cancelled = 1; + + while (acb->status == -EINPROGRESS) { + qemu_aio_wait(); + } + + qemu_aio_release(acb); } static AIOPool rbd_aio_pool = { @@ -646,7 +648,8 @@ static void rbd_aio_bh_cb(void *opaque) qemu_bh_delete(acb->bh); acb->bh = NULL; - qemu_aio_release(acb); + if (!acb->cancelled) + qemu_aio_release(acb); } static int rbd_aio_discard_wrapper(rbd_image_t image, @@ -691,6 +694,7 @@ static BlockDriverAIOCB *rbd_start_aio(BlockDriverState *bs, acb->s = s; acb->cancelled = 0; acb->bh = NULL; + acb->status = -EINPROGRESS; if (cmd == RBD_AIO_WRITE) { qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size); @@ -737,7 +741,8 @@ static BlockDriverAIOCB *rbd_start_aio(BlockDriverState *bs, failed: g_free(rcb); s->qemu_aio_count--; - qemu_aio_release(acb); + if (!acb->cancelled) + qemu_aio_release(acb); return NULL; }