From 2f0c6e7a650de133eccd94e9bb6cf7b2070f07f1 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Fri, 24 Apr 2020 14:54:44 +0200 Subject: [PATCH] file-posix: Support BDRV_REQ_ZERO_WRITE for truncate For regular files, we always get BDRV_REQ_ZERO_WRITE behaviour from the OS, so we can advertise the flag and just ignore it. Signed-off-by: Kevin Wolf Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Alberto Garcia Reviewed-by: Max Reitz Message-Id: <20200424125448.63318-7-kwolf@redhat.com> Signed-off-by: Kevin Wolf --- block/file-posix.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/block/file-posix.c b/block/file-posix.c index 58326a0a60..bf09ad8bc0 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -702,6 +702,10 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, #endif bs->supported_zero_flags = BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK; + if (S_ISREG(st.st_mode)) { + /* When extending regular files, we get zeros from the OS */ + bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE; + } ret = 0; fail: if (filename && (bdrv_flags & BDRV_O_TEMPORARY)) { -- 2.30.2