[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>
---
qemu-io-cmds.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index 46593d632d8f..954955c12fb9 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -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 {
--
2.33.1