From d1a764d126aa9bd1b519855607f55daf266b07bf Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Wed, 21 Oct 2020 17:58:44 +0300 Subject: block: introduce BDRV_REQ_NO_WAIT flag 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 Reviewed-by: Max Reitz Message-Id: <20201021145859.11201-7-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz --- block/io.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'block') diff --git a/block/io.c b/block/io.c index fadfed3ab8..95b1c56c06 100644 --- a/block/io.c +++ b/block/io.c @@ -1858,9 +1858,18 @@ 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_LOCK_GUARD(&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); } else { bdrv_wait_serialising_requests(req); } -- cgit v1.2.3-55-g7522