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authorEric Blake <eblake@redhat.com>2020-04-28 15:28:58 -0500
committerKevin Wolf <kwolf@redhat.com>2020-05-08 13:26:35 +0200
commit8e519795041e3293ab6b4e67f5416fa80dc0efc4 (patch)
treed84c274024e3d6e856bd4d1a3e48d86027d61d65
parent5e09bcee5ba2c69f79d59513436fc92db49ec302 (diff)
downloadfocaccia-qemu-8e519795041e3293ab6b4e67f5416fa80dc0efc4.tar.gz
focaccia-qemu-8e519795041e3293ab6b4e67f5416fa80dc0efc4.zip
file-win32: Support BDRV_REQ_ZERO_WRITE for truncate
When using bdrv_file, .bdrv_has_zero_init_truncate always returns 1;
therefore, we can behave just like file-posix, and always implement
BDRV_REQ_ZERO_WRITE by ignoring it since the OS gives it to us for
free (note that file-posix.c had to use an 'if' because it shared code
between regular files and block devices, but in file-win32.c,
bdrv_host_device uses a separate .bdrv_file_open).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200428202905.770727-3-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r--block/file-win32.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/block/file-win32.c b/block/file-win32.c
index a6b0dda5c3..fa569685d8 100644
--- a/block/file-win32.c
+++ b/block/file-win32.c
@@ -408,6 +408,9 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
         win32_aio_attach_aio_context(s->aio, bdrv_get_aio_context(bs));
     }
 
+    /* When extending regular files, we get zeros from the OS */
+    bs->supported_truncate_flags = BDRV_REQ_ZERO_WRITE;
+
     ret = 0;
 fail:
     qemu_opts_del(opts);