| Message ID | 1354225046-9761-1-git-send-email-s.priebe@profihost.ag |
|---|---|
| State | New |
| Headers | show |
On Thu, Nov 29, 2012 at 10:37 PM, Stefan Priebe <s.priebe@profihost.ag> wrote: > @@ -568,6 +562,10 @@ static void qemu_rbd_aio_cancel(BlockDriverAIOCB *blockacb) > { > RBDAIOCB *acb = (RBDAIOCB *) blockacb; > acb->cancelled = 1; > + > + while (acb->status == -EINPROGRESS) { > + qemu_aio_wait(); > + } > } > > static const AIOCBInfo rbd_aiocb_info = { > @@ -639,6 +637,7 @@ 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); > } We cannot release acb in rbd_aio_bh_cb() when acb->cancelled == 1 because qemu_rbd_aio_cancel() still accesses it. This was discussed in an early version of the patch. Stefan
fixed in V6 Am 30.11.2012 09:26, schrieb Stefan Hajnoczi: > On Thu, Nov 29, 2012 at 10:37 PM, Stefan Priebe <s.priebe@profihost.ag> wrote: >> @@ -568,6 +562,10 @@ static void qemu_rbd_aio_cancel(BlockDriverAIOCB *blockacb) >> { >> RBDAIOCB *acb = (RBDAIOCB *) blockacb; >> acb->cancelled = 1; >> + >> + while (acb->status == -EINPROGRESS) { >> + qemu_aio_wait(); >> + } >> } >> >> static const AIOCBInfo rbd_aiocb_info = { >> @@ -639,6 +637,7 @@ 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); >> } > > We cannot release acb in rbd_aio_bh_cb() when acb->cancelled == 1 > because qemu_rbd_aio_cancel() still accesses it. This was discussed > in an early version of the patch. > > Stefan >
diff --git a/block/rbd.c b/block/rbd.c index f3becc7..3bc9c7a 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 +562,10 @@ static void qemu_rbd_aio_cancel(BlockDriverAIOCB *blockacb) { RBDAIOCB *acb = (RBDAIOCB *) blockacb; acb->cancelled = 1; + + while (acb->status == -EINPROGRESS) { + qemu_aio_wait(); + } } static const AIOCBInfo rbd_aiocb_info = { @@ -639,6 +637,7 @@ 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); } @@ -685,6 +684,7 @@ 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);
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. Changes since PATCHv4: - removed unnecessary qemu_vfree of acb->bounce as BH will always run Changes since PATCHv3: - removed unnecessary if condition in rbd_start_aio as we haven't start io yet - moved acb->status = 0 to rbd_aio_bh_cb so qemu_aio_wait always waits until BH was executed Changes since PATCHv2: - fixed missing braces - added vfree for bounce Signed-off-by: Stefan Priebe <s.priebe@profihost.ag> --- block/rbd.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)