From mboxrd@z Thu Jan 1 00:00:00 1970 From: 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> Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org To: qemu-devel@nongnu.org Cc: stefanha@gmail.com, ceph-devel@vger.kernel.org, pbonzini@redhat.com, Stefan Priebe , josh.durgin@inktank.com List-Id: 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; } -- 1.7.10.4