Commit cffb1ec6 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Stefan Hajnoczi
Browse files

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: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarPeter Lieven <pl@kamp.de>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 95de6d70

block/qcow2.c

+1 −0
Original line number Diff line number Diff line
@@ -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 "

block/qed.c

+1 −0
Original line number Diff line number Diff line
@@ -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);

block/vmdk.c

+4 −0
Original line number Diff line number Diff line
@@ -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 {