On 11/22/2012 02:00 AM, Stefan Priebe 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();
+ }
+
There should be a qemu_vfree(acb->bounce); here
+ 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_vfree(acb->bounce) should be here as well, although that's a
separate bug that's probably never hit.
+ qemu_aio_release(acb);
return NULL;
}
--
To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
