From cffb1ec600de83f693a23578fc2f344c1af9b96f Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 22 Nov 2013 13:39:51 +0100 Subject: [PATCH] block drivers: expose requirement for write same alignment from formats This will let misaligned but large requests use zero clusters. This is important because the cluster size is not guest visible. Signed-off-by: Paolo Bonzini Reviewed-by: Peter Lieven Signed-off-by: Stefan Hajnoczi --- block/qcow2.c | 1 + block/qed.c | 1 + block/vmdk.c | 4 ++++ 3 files changed, 6 insertions(+) diff --git a/block/qcow2.c b/block/qcow2.c index 41e454a2f1..19e037406c 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -718,6 +718,7 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, } qemu_opts_del(opts); + bs->bl.write_zeroes_alignment = s->cluster_sectors; if (s->use_lazy_refcounts && s->qcow_version < 3) { error_setg(errp, "Lazy refcounts require a qcow2 image with at least " diff --git a/block/qed.c b/block/qed.c index 59516a5704..450a1fa2e9 100644 --- a/block/qed.c +++ b/block/qed.c @@ -495,6 +495,7 @@ static int bdrv_qed_open(BlockDriverState *bs, QDict *options, int flags, } } + bs->bl.write_zeroes_alignment = s->header.cluster_size >> BDRV_SECTOR_BITS; s->need_check_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, qed_need_check_timer_cb, s); diff --git a/block/vmdk.c b/block/vmdk.c index eb84f46a7b..0734bc200c 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -428,6 +428,10 @@ static int vmdk_add_extent(BlockDriverState *bs, extent->l2_size = l2_size; extent->cluster_sectors = flat ? sectors : cluster_sectors; + if (!flat) { + bs->bl.write_zeroes_alignment = + MAX(bs->bl.write_zeroes_alignment, cluster_sectors); + } if (s->num_extents > 1) { extent->end_sector = (*(extent - 1)).end_sector + extent->sectors; } else { -- 2.11.0