From 2e36da62cf36d83897f922969e4523317e5f6ad3 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Wed, 21 Oct 2020 17:58:40 +0300 Subject: [PATCH] block/io.c: drop assertion on double waiting for request serialisation The comments states, that on misaligned request we should have already been waiting. But for bdrv_padding_rmw_read, we called bdrv_mark_request_serialising with align = request_alignment, and now we serialise with align = cluster_size. So we may have to wait again with larger alignment. Note, that the only user of BDRV_REQ_SERIALISING is backup which issues cluster-aligned requests, so seems the assertion should not fire for now. But it's wrong anyway. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Paolo Bonzini Message-Id: <20201021145859.11201-3-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz --- block/io.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) diff --git a/block/io.c b/block/io.c index 24205f5168..27370107b2 100644 --- a/block/io.c +++ b/block/io.c @@ -1827,7 +1827,6 @@ bdrv_co_write_req_prepare(BdrvChild *child, int64_t offset, uint64_t bytes, BdrvTrackedRequest *req, int flags) { BlockDriverState *bs = child->bs; - bool waited; int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE); if (bs->read_only) { @@ -1839,15 +1838,7 @@ bdrv_co_write_req_prepare(BdrvChild *child, int64_t offset, uint64_t bytes, assert(!(flags & ~BDRV_REQ_MASK)); if (flags & BDRV_REQ_SERIALISING) { - waited = bdrv_mark_request_serialising(req, bdrv_get_cluster_size(bs)); - /* - * For a misaligned request we should have already waited earlier, - * because we come after bdrv_padding_rmw_read which must be called - * with the request already marked as serialising. - */ - assert(!waited || - (req->offset == req->overlap_offset && - req->bytes == req->overlap_bytes)); + bdrv_mark_request_serialising(req, bdrv_get_cluster_size(bs)); } else { bdrv_wait_serialising_requests(req); } -- 2.11.4.GIT