From 4bc267a7c7cf204b05d3d1f01625691540a7b965 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Fri, 7 Feb 2020 19:12:31 +0300 Subject: [PATCH] block/backup-top: fix flags handling backup-top "supports" write-unchanged, by skipping CBW operation in backup_top_co_pwritev. But it forgets to do the same in backup_top_co_pwrite_zeroes, as well as declare support for BDRV_REQ_WRITE_UNCHANGED. Fix this, and, while being here, declare also support for flags supported by source child. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-Id: <20200207161231.32707-1-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz --- block/backup-top.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) diff --git a/block/backup-top.c b/block/backup-top.c index fa78f3256d..1bfb360bd3 100644 --- a/block/backup-top.c +++ b/block/backup-top.c @@ -48,11 +48,17 @@ static coroutine_fn int backup_top_co_preadv( } static coroutine_fn int backup_top_cbw(BlockDriverState *bs, uint64_t offset, - uint64_t bytes) + uint64_t bytes, BdrvRequestFlags flags) { BDRVBackupTopState *s = bs->opaque; - uint64_t end = QEMU_ALIGN_UP(offset + bytes, s->bcs->cluster_size); - uint64_t off = QEMU_ALIGN_DOWN(offset, s->bcs->cluster_size); + uint64_t off, end; + + if (flags & BDRV_REQ_WRITE_UNCHANGED) { + return 0; + } + + off = QEMU_ALIGN_DOWN(offset, s->bcs->cluster_size); + end = QEMU_ALIGN_UP(offset + bytes, s->bcs->cluster_size); return block_copy(s->bcs, off, end - off, NULL); } @@ -60,7 +66,7 @@ static coroutine_fn int backup_top_cbw(BlockDriverState *bs, uint64_t offset, static int coroutine_fn backup_top_co_pdiscard(BlockDriverState *bs, int64_t offset, int bytes) { - int ret = backup_top_cbw(bs, offset, bytes); + int ret = backup_top_cbw(bs, offset, bytes, 0); if (ret < 0) { return ret; } @@ -71,7 +77,7 @@ static int coroutine_fn backup_top_co_pdiscard(BlockDriverState *bs, static int coroutine_fn backup_top_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int bytes, BdrvRequestFlags flags) { - int ret = backup_top_cbw(bs, offset, bytes); + int ret = backup_top_cbw(bs, offset, bytes, flags); if (ret < 0) { return ret; } @@ -84,11 +90,9 @@ static coroutine_fn int backup_top_co_pwritev(BlockDriverState *bs, uint64_t bytes, QEMUIOVector *qiov, int flags) { - if (!(flags & BDRV_REQ_WRITE_UNCHANGED)) { - int ret = backup_top_cbw(bs, offset, bytes); - if (ret < 0) { - return ret; - } + int ret = backup_top_cbw(bs, offset, bytes, flags); + if (ret < 0) { + return ret; } return bdrv_co_pwritev(bs->backing, offset, bytes, qiov, flags); @@ -196,8 +200,13 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source, return NULL; } - top->total_sectors = source->total_sectors; state = top->opaque; + top->total_sectors = source->total_sectors; + top->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED | + (BDRV_REQ_FUA & source->supported_write_flags); + top->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED | + ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) & + source->supported_zero_flags); bdrv_ref(target); state->target = bdrv_attach_child(top, target, "target", &child_file, errp);