From 8f23aaf5d6a5458e251c5d5d0555d9e515355e35 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Tue, 28 Apr 2020 15:28:59 -0500 Subject: nfs: Support BDRV_REQ_ZERO_WRITE for truncate Our .bdrv_has_zero_init_truncate returns 1 if we detect that the OS always 0-fills; we can use that same knowledge to implement BDRV_REQ_ZERO_WRITE by ignoring it when the OS gives it to us for free. Signed-off-by: Eric Blake Message-Id: <20200428202905.770727-4-eblake@redhat.com> Signed-off-by: Kevin Wolf --- block/nfs.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'block/nfs.c') diff --git a/block/nfs.c b/block/nfs.c index 385d756e1d..76daa7c9f6 100644 --- a/block/nfs.c +++ b/block/nfs.c @@ -620,6 +620,9 @@ static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags, } bs->total_sectors = ret; + if (client->has_zero_init) { + bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE; + } return 0; } -- cgit v1.2.3