| Message ID | 20211203231539.3900865-3-eblake@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | spec: Add NBD_OPT_EXTENDED_HEADERS | expand |
04.12.2021 02:15, Eric Blake wrote: > 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> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
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 {
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> --- qemu-io-cmds.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)