Previously, it was not possible to use wait_for_overlapping_requests()
between tracked_request_begin()/end() because it would wait for itself.
Ignore the current request in the overlap check and run more of the
bdrv_co_do_preadv/pwritev code with a BdrvTrackedRequest present.
Signed-off-by: Kevin Wolf <kw...@redhat.com>
Reviewed-by: Max Reitz <mre...@redhat.com>
---
block.c | 38 ++++++++++++++++++++------------------
1 file changed, 20 insertions(+), 18 deletions(-)
diff --git a/block.c b/block.c
index 85f28ab..18dcd43 100644
--- a/block.c
+++ b/block.c
@@ -2106,7 +2106,7 @@ static bool tracked_request_overlaps(BdrvTrackedRequest
*req,
}
static void coroutine_fn wait_for_overlapping_requests(BlockDriverState *bs,
- int64_t offset, unsigned int bytes)
+ BdrvTrackedRequest *self, int64_t offset, unsigned int bytes)
{
BdrvTrackedRequest *req;
int64_t cluster_offset;
@@ -2124,6 +2124,9 @@ static void coroutine_fn
wait_for_overlapping_requests(BlockDriverState *bs,
do {
retry = false;
QLIST_FOREACH(req, &bs->tracked_requests, list) {
+ if (req == self) {
+ continue;
+ }
if (tracked_request_overlaps(req, cluster_offset, cluster_bytes)) {
/* Hitting this means there was a reentrant request, for
* example, a block driver issuing nested requests. This must
@@ -2726,10 +2729,10 @@ err:
* implemented by the caller.
*/
static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
- int64_t offset, unsigned int bytes, QEMUIOVector *qiov, int flags)
+ BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
+ QEMUIOVector *qiov, int flags)
{
BlockDriver *drv = bs->drv;
- BdrvTrackedRequest req;
int ret;
int64_t sector_num = offset >> BDRV_SECTOR_BITS;
@@ -2744,11 +2747,9 @@ static int coroutine_fn
bdrv_aligned_preadv(BlockDriverState *bs,
}
if (bs->copy_on_read_in_flight) {
- wait_for_overlapping_requests(bs, offset, bytes);
+ wait_for_overlapping_requests(bs, req, offset, bytes);
}
- tracked_request_begin(&req, bs, offset, bytes, false);
-
if (flags & BDRV_REQ_COPY_ON_READ) {
int pnum;
@@ -2795,8 +2796,6 @@ static int coroutine_fn
bdrv_aligned_preadv(BlockDriverState *bs,
}
out:
- tracked_request_end(&req);
-
if (flags & BDRV_REQ_COPY_ON_READ) {
bs->copy_on_read_in_flight--;
}
@@ -2812,6 +2811,8 @@ static int coroutine_fn
bdrv_co_do_preadv(BlockDriverState *bs,
BdrvRequestFlags flags)
{
BlockDriver *drv = bs->drv;
+ BdrvTrackedRequest req;
+
/* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */
uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment);
uint8_t *head_buf = NULL;
@@ -2862,9 +2863,11 @@ static int coroutine_fn
bdrv_co_do_preadv(BlockDriverState *bs,
bytes = ROUND_UP(bytes, align);
}
- ret = bdrv_aligned_preadv(bs, offset, bytes,
+ tracked_request_begin(&req, bs, offset, bytes, false);
+ ret = bdrv_aligned_preadv(bs, &req, offset, bytes,
use_local_qiov ? &local_qiov : qiov,
flags);
+ tracked_request_end(&req);
if (use_local_qiov) {
qemu_iovec_destroy(&local_qiov);
@@ -2983,10 +2986,10 @@ static int coroutine_fn
bdrv_co_do_write_zeroes(BlockDriverState *bs,
* Forwards an already correctly aligned write request to the BlockDriver.
*/
static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs,
- int64_t offset, unsigned int bytes, QEMUIOVector *qiov, int flags)
+ BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
+ QEMUIOVector *qiov, int flags)
{
BlockDriver *drv = bs->drv;
- BdrvTrackedRequest req;
int ret;
int64_t sector_num = offset >> BDRV_SECTOR_BITS;
@@ -2996,12 +2999,10 @@ static int coroutine_fn
bdrv_aligned_pwritev(BlockDriverState *bs,
assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
if (bs->copy_on_read_in_flight) {
- wait_for_overlapping_requests(bs, offset, bytes);
+ wait_for_overlapping_requests(bs, req, offset, bytes);
}
- tracked_request_begin(&req, bs, offset, bytes, true);
-
- ret = notifier_with_return_list_notify(&bs->before_write_notifiers, &req);
+ ret = notifier_with_return_list_notify(&bs->before_write_notifiers, req);
if (ret < 0) {
/* Do nothing, write notifier decided to fail this request */
@@ -3024,8 +3025,6 @@ static int coroutine_fn
bdrv_aligned_pwritev(BlockDriverState *bs,
bs->total_sectors = MAX(bs->total_sectors, sector_num + nb_sectors);
}
- tracked_request_end(&req);
-
return ret;
}
@@ -3036,6 +3035,7 @@ static int coroutine_fn
bdrv_co_do_pwritev(BlockDriverState *bs,
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags)
{
+ BdrvTrackedRequest req;
int ret;
if (!bs->drv) {
@@ -3054,7 +3054,9 @@ static int coroutine_fn
bdrv_co_do_pwritev(BlockDriverState *bs,
bdrv_io_limits_intercept(bs, bytes >> BDRV_SECTOR_BITS, true);
}
- ret = bdrv_aligned_pwritev(bs, offset, bytes, qiov, flags);
+ tracked_request_begin(&req, bs, offset, bytes, true);
+ ret = bdrv_aligned_pwritev(bs, &req, offset, bytes, qiov, flags);
+ tracked_request_end(&req);
return ret;
}
--
1.8.1.4
