From 49577723d40f56f7ac3d2f880423ae6652a2922d Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Tue, 24 Aug 2021 11:38:28 +0300 Subject: block-copy: move detecting fleecing scheme to block-copy We want to simplify initialization interface of copy-before-write filter as we are going to make it public. So, let's detect fleecing scheme exactly in block-copy code, to not pass this information through extra levels. Why not just set BDRV_REQ_SERIALISING unconditionally: because we are going to implement new more efficient fleecing scheme which will not rely on backing feature. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Hanna Reitz Message-Id: <20210824083856.17408-7-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz --- block/backup.c | 21 +-------------------- 1 file changed, 1 insertion(+), 20 deletions(-) (limited to 'block/backup.c') diff --git a/block/backup.c b/block/backup.c index ac91821b08..84f9a5f02c 100644 --- a/block/backup.c +++ b/block/backup.c @@ -407,7 +407,6 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, int64_t len, target_len; BackupBlockJob *job = NULL; int64_t cluster_size; - BdrvRequestFlags write_flags; BlockDriverState *cbw = NULL; BlockCopyState *bcs = NULL; @@ -504,26 +503,8 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs, goto error; } - /* - * If source is in backing chain of target assume that target is going to be - * used for "image fleecing", i.e. it should represent a kind of snapshot of - * source at backup-start point in time. And target is going to be read by - * somebody (for example, used as NBD export) during backup job. - * - * In this case, we need to add BDRV_REQ_SERIALISING write flag to avoid - * intersection of backup writes and third party reads from target, - * otherwise reading from target we may occasionally read already updated by - * guest data. - * - * For more information see commit f8d59dfb40bb and test - * tests/qemu-iotests/222 - */ - write_flags = (bdrv_chain_contains(target, bs) ? BDRV_REQ_SERIALISING : 0) | - (compress ? BDRV_REQ_WRITE_COMPRESSED : 0), - cbw = bdrv_cbw_append(bs, target, filter_node_name, - cluster_size, perf, - write_flags, &bcs, errp); + cluster_size, perf, compress, &bcs, errp); if (!cbw) { goto error; } -- cgit v1.2.3