Commit 3f6de653 authored by Kevin Wolf's avatar Kevin Wolf
Browse files

vpc: Don't round up already aligned BAT sizes 

As reported on Launchpad, Azure apparently doesn't accept images for
upload that are not both aligned to 1 MB blocks and have a BAT size that
matches the image size exactly.

As far as I can tell, there is no real reason why we create a BAT that
is one entry longer than necessary for aligned image sizes, so change
that.

(Even though the condition is only mentioned as "should" in the spec and
previous products accepted larger BATs - but we'll try to maintain
compatibility with as many of Microsoft's ever-changing interpretations
of the VHD spec as possible.)

Fixes: https://bugs.launchpad.net/bugs/1870098


Reported-by: Tobias Witek
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
Message-Id: <20200402093603.2369-1-kwolf@redhat.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Reviewed-by: default avatarPhilippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 7f16476f

block/vpc.c

+1 −1
Original line number Diff line number Diff line
@@ -835,7 +835,7 @@ static int create_dynamic_disk(BlockBackend *blk, uint8_t *buf, 


    /* Write the footer (twice: at the beginning and at the end) */

    block_size = 0x200000;

    num_bat_entries = (total_sectors + block_size / 512) / (block_size / 512);

    num_bat_entries = DIV_ROUND_UP(total_sectors, block_size / 512);



    ret = blk_pwrite(blk, offset, buf, HEADER_SIZE, 0);

    if (ret < 0) {