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authorPaolo Bonzini <pbonzini@redhat.com>2013-11-22 13:39:51 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2013-12-03 15:26:49 +0100
commitcffb1ec600de83f693a23578fc2f344c1af9b96f (patch)
treedc6c9e603941735a69cab5adecbeb9171a980e23
parent95de6d7078b029b73708059a17cef20f332adcb7 (diff)
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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 <pbonzini@redhat.com> Reviewed-by: Peter Lieven <pl@kamp.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-rw-r--r--block/qcow2.c1
-rw-r--r--block/qed.c1
-rw-r--r--block/vmdk.c4
3 files changed, 6 insertions, 0 deletions
diff --git a/block/qcow2.c b/block/qcow2.c
index 41e454a..19e0374 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 59516a5..450a1fa 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 eb84f46..0734bc2 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 {