@@ -67,8 +67,15 @@ typedef enum {
* written to qiov parameter which may be NULL.
*/
BDRV_REQ_PREFETCH = 0x200,
+
+ /*
+ * If we need to wait for other requests, just fail immediately. Used
+ * only together with BDRV_REQ_SERIALISING.
+ */
+ BDRV_REQ_NO_WAIT = 0x400,
+
/* Mask of valid flags */
- BDRV_REQ_MASK = 0x3ff,
+ BDRV_REQ_MASK = 0x7ff,
} BdrvRequestFlags;
typedef struct BlockSizes {
@@ -1911,9 +1911,20 @@ bdrv_co_write_req_prepare(BdrvChild *child, int64_t offset, uint64_t bytes,
assert(!(bs->open_flags & BDRV_O_INACTIVE));
assert((bs->open_flags & BDRV_O_NO_IO) == 0);
assert(!(flags & ~BDRV_REQ_MASK));
+ assert(!((flags & BDRV_REQ_NO_WAIT) && !(flags & BDRV_REQ_SERIALISING)));
if (flags & BDRV_REQ_SERIALISING) {
- bdrv_make_request_serialising(req, bdrv_get_cluster_size(bs));
+ qemu_co_mutex_lock(&bs->reqs_lock);
+
+ tracked_request_set_serialising(req, bdrv_get_cluster_size(bs));
+
+ if ((flags & BDRV_REQ_NO_WAIT) && bdrv_find_conflicting_request(req)) {
+ return -EBUSY;
+ }
+
+ bdrv_wait_serialising_requests_locked(req);
+
+ qemu_co_mutex_unlock(&bs->reqs_lock);
} else {
bdrv_wait_serialising_requests(req);
}
Add flag to make serialising request no wait: if there are conflicting requests, just return error immediately. It's will be used in upcoming preallocate filter. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> --- include/block/block.h | 9 ++++++++- block/io.c | 13 ++++++++++++- 2 files changed, 20 insertions(+), 2 deletions(-)