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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@redhat.com>
Message-Id: <20211203231539.3900865-3-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
This commit is contained in:
Eric Blake 2021-12-03 17:15:27 -06:00
parent 314b902621
commit 087f2fb376
1 changed files with 2 additions and 5 deletions
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7
qemu-io-cmds.c
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@ -1993,11 +1993,9 @@ static int map_is_allocated(BlockDriverState *bs, int64_t offset,
int64_t bytes, int64_t *pnum)
{
int64_t num;
int num_checked;
int ret, firstret;
num_checked = MIN(bytes, BDRV_REQUEST_MAX_BYTES);
ret = bdrv_is_allocated(bs, offset, num_checked, &num);
ret = bdrv_is_allocated(bs, offset, bytes, &num);
if (ret < 0) {
return ret;
}
@ -2009,8 +2007,7 @@ static int map_is_allocated(BlockDriverState *bs, int64_t offset,
offset += num;
bytes -= num;
num_checked = MIN(bytes, BDRV_REQUEST_MAX_BYTES);
ret = bdrv_is_allocated(bs, offset, num_checked, &num);
ret = bdrv_is_allocated(bs, offset, bytes, &num);
if (ret == firstret && num) {
*pnum += num;
} else {