| Message ID | 1354199315-21683-1-git-send-email-s.priebe@profihost.ag (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
----- Messaggio originale ----- > Da: "Stefan Priebe" <s.priebe@profihost.ag> > A: qemu-devel@nongnu.org > Cc: stefanha@gmail.com, "josh durgin" <josh.durgin@inktank.com>, ceph-devel@vger.kernel.org, pbonzini@redhat.com, > "Stefan Priebe" <s.priebe@profihost.ag> > Inviato: Giovedì, 29 novembre 2012 15:28:35 > Oggetto: [PATCHv4] rbd block driver 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. > > 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 | 16 +++++++++------- > 1 file changed, 9 insertions(+), 7 deletions(-) > > diff --git a/block/rbd.c b/block/rbd.c > index f3becc7..28e94ab 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_vfree(acb->bounce); This vfree is not needed, since the BH will run and do the free. Otherwise looks ok. > } > > static const AIOCBInfo rbd_aiocb_info = { > @@ -639,6 +639,7 @@ 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 +686,7 @@ 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); > -- > 1.7.10.4 > > -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Paolo, Am 29.11.2012 16:23, schrieb Paolo Bonzini: >> + qemu_vfree(acb->bounce); > > This vfree is not needed, since the BH will run and do the free. new patch v5 sent. Greets, Stefan -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/block/rbd.c b/block/rbd.c index f3becc7..28e94ab 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_vfree(acb->bounce); } static const AIOCBInfo rbd_aiocb_info = { @@ -639,6 +639,7 @@ 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 +686,7 @@ 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 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 | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-)