From ea80b906f445969a5ccc781beb4e8bb7f60bbdbb Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Mon, 31 Aug 2009 12:26:57 +0200 Subject: [PATCH] qcow2: Fix metadata preallocation The wrong version of the preallocation patch has been applied, so this is the remaining diff. We can't use truncate to grow the image file to the right size because we don't know if metadata has been written after the last data cluster. In this case truncate would shrink the file and destroy its metadata. Write a zero sector at the end of the virtual disk instead to ensure that the file is big enough. Signed-off-by: Kevin Wolf Signed-off-by: Anthony Liguori --- block/qcow2.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/qcow2.c b/block/qcow2.c index 9637f2ea3a..b8eae902a3 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -677,7 +677,9 @@ static int preallocate(BlockDriverState *bs) * EOF). Extend the image to the last allocated sector. */ if (cluster_offset != 0) { - bdrv_truncate(s->hd, cluster_offset + (num << 9)); + uint8_t buf[512]; + memset(buf, 0, 512); + bdrv_write(s->hd, (cluster_offset >> 9) + num - 1, buf, 1); } return 0; -- GitLab