Re: [Libguestfs] [PATCH 02/14] qemu-io: Utilize 64-bit status during map

The block layer has supported 64-bit block status from drivers since commit 86a3d5c688 ("block: Add .bdrv_co_block_status() callback", v2.12) and friends, with individual driver callbacks responsible for capping things where necessary. Artificially capping things below 2G in the qemu-io 'map' command, added in commit d6a644bbfe ("block: Make bdrv_is_allocated() byte-based", v2.10) is thus no longer necessary. One way to test this is with qemu-nbd as server on a raw file larger than 4G (the entire file should show as allocated), plus 'qemu-io -f raw -c map nbd://localhost --trace=nbd_\*' as client. Prior to this patch, the NBD_CMD_BLOCK_STATUS requests are fragmented at 0x7ffffe00 distances; with this patch, the fragmenting changes to 0x7fffffff (since the NBD protocol is currently still limited to 32-bit transactions - see block/nbd.c:nbd_client_co_block_status). Then in later patches, once I add an NBD extension for a 64-bit block status, the same map command completes with just one NBD_CMD_BLOCK_STATUS. Signed-off-by: Eric Blake<eblake(a)redhat.com>