Commit f0ad5712 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Stefan Hajnoczi
Browse files

block: return BDRV_BLOCK_ZERO past end of backing file 



If the sectors are unallocated and we are past the end of the
backing file, they will read as zero.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 415b5b01

block.c

+10 −2
Original line number Diff line number Diff line
@@ -3102,8 +3102,16 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs, 
        return ret;

    }



    if (!(ret & BDRV_BLOCK_DATA) && bdrv_has_zero_init(bs)) {

    if (!(ret & BDRV_BLOCK_DATA)) {

        if (bdrv_has_zero_init(bs)) {

            ret |= BDRV_BLOCK_ZERO;

        } else {

            BlockDriverState *bs2 = bs->backing_hd;

            int64_t length2 = bdrv_getlength(bs2);

            if (length2 >= 0 && sector_num >= (length2 >> BDRV_SECTOR_BITS)) {

                ret |= BDRV_BLOCK_ZERO;

            }

        }

    }

    return ret;

}