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authorStefan Priebe <s.priebe@profihost.ag>2012-11-30 09:55:46 +0100
committerKevin Wolf <kwolf@redhat.com>2012-12-11 11:05:11 +0100
commit473c7f0255920bcaf37411990a3725898772817f (patch)
tree9e6254bdbf1ad891fd2a786fdee9b4f5b507e655
parent791bfa35ee00ca10b13bedfb048ffda385b151c7 (diff)
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 <s.priebe@profihost.ag> Reviewed-by: Stefan Hajnoczi <stefanha@gmail.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r--block/rbd.c20
1 files changed, 12 insertions, 8 deletions
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);