On Thu, Nov 22, 2012 at 10:00 AM, Stefan Priebe <s.priebe@xxxxxxxxxxxx> wrote:
> 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 <s.priebe@xxxxxxxxxxxx>
> ---
> 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)
Missing braces, please read CODING_STYLE.
> + 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);
Also here.
> return NULL;
> }
>
> --
> 1.7.10.4
>
>
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