Commit 2253d86e authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Max Reitz
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qemu-img: convert: don't use unallocated_blocks_are_zero 



qemu-img convert wants to distinguish ZERO which comes from short
backing files. unallocated_blocks_are_zero field of bdi is unrelated:
space after EOF is always considered to be zero anyway. So, just make
post_backing_zero true in case of short backing file.

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Message-Id: <20200528094405.145708-2-vsementsov@virtuozzo.com>
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
parent a2cd85f6

qemu-img.c

+1 −3
Original line number Diff line number Diff line
@@ -1681,7 +1681,6 @@ typedef struct ImgConvertState { 
    BlockBackend *target;

    bool has_zero_init;

    bool compressed;

    bool unallocated_blocks_are_zero;

    bool target_is_new;

    bool target_has_backing;

    int64_t target_backing_sectors; /* negative if unknown */
@@ -1726,7 +1725,7 @@ static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num) 


    if (s->target_backing_sectors >= 0) {

        if (sector_num >= s->target_backing_sectors) {

            post_backing_zero = s->unallocated_blocks_are_zero;

            post_backing_zero = true;

        } else if (sector_num + n > s->target_backing_sectors) {

            /* Split requests around target_backing_sectors (because

             * starting from there, zeros are handled differently) */
@@ -2678,7 +2677,6 @@ static int img_convert(int argc, char **argv) 
    } else {

        s.compressed = s.compressed || bdi.needs_compressed_writes;

        s.cluster_sectors = bdi.cluster_size / BDRV_SECTOR_SIZE;

        s.unallocated_blocks_are_zero = bdi.unallocated_blocks_are_zero;

    }



    ret = convert_do_copy(&s);