From 473c7f0255920bcaf37411990a3725898772817f Mon Sep 17 00:00:00 2001 From: Stefan Priebe Date: Fri, 30 Nov 2012 09:55:46 +0100 Subject: rbd: Fix race between aio completition and aio cancel 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 Reviewed-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- block/rbd.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) (limited to 'block') diff --git a/block/rbd.c b/block/rbd.c index f3becc7a8b..737bab16cc 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 || @@ -409,7 +404,6 @@ static void qemu_rbd_complete_aio(RADOSCB *rcb) /* 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); } @@ -568,6 +562,12 @@ 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 const AIOCBInfo rbd_aiocb_info = { @@ -639,8 +639,11 @@ static void rbd_aio_bh_cb(void *opaque) acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : acb->ret)); qemu_bh_delete(acb->bh); acb->bh = NULL; + acb->status = 0; - qemu_aio_release(acb); + if (!acb->cancelled) { + qemu_aio_release(acb); + } } static int rbd_aio_discard_wrapper(rbd_image_t image, @@ -685,6 +688,7 @@ 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); -- cgit v1.2.3