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| author | Eric Blake <eblake@redhat.com> | 2019-08-23 09:37:24 -0500 |
|---|---|---|
| committer | Eric Blake <eblake@redhat.com> | 2019-09-05 16:03:26 -0500 |
| commit | f061656cc355161f9984237298c45762ce5187d3 (patch) | |
| tree | 7d240be86555e9b9cb558af1e7442febed69a424 /block | |
| parent | 0a4795455ceeebdca999a60583dd42434f2ec0d1 (diff) | |
| download | qemu-f061656cc355161f9984237298c45762ce5187d3.zip qemu-f061656cc355161f9984237298c45762ce5187d3.tar.gz qemu-f061656cc355161f9984237298c45762ce5187d3.tar.bz2 | |
nbd: Implement client use of NBD FAST_ZERO
The client side is fairly straightforward: if the server advertised
fast zero support, then we can map that to BDRV_REQ_NO_FALLBACK
support. A server that advertises FAST_ZERO but not WRITE_ZEROES
is technically broken, but we can ignore that situation as it does
not change our behavior.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190823143726.27062-4-eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/nbd.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/block/nbd.c b/block/nbd.c index c4c91a1..813c40d 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -1044,6 +1044,10 @@ static int nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, if (!(flags & BDRV_REQ_MAY_UNMAP)) { request.flags |= NBD_CMD_FLAG_NO_HOLE; } + if (flags & BDRV_REQ_NO_FALLBACK) { + assert(s->info.flags & NBD_FLAG_SEND_FAST_ZERO); + request.flags |= NBD_CMD_FLAG_FAST_ZERO; + } if (!bytes) { return 0; @@ -1239,6 +1243,9 @@ static int nbd_client_connect(BlockDriverState *bs, Error **errp) } if (s->info.flags & NBD_FLAG_SEND_WRITE_ZEROES) { bs->supported_zero_flags |= BDRV_REQ_MAY_UNMAP; + if (s->info.flags & NBD_FLAG_SEND_FAST_ZERO) { + bs->supported_zero_flags |= BDRV_REQ_NO_FALLBACK; + } } s->sioc = sioc; |