This patch is part of the Fast Virtual Disk (FVD) proposal.
See http://wiki.qemu.org/Features/FVD.
This patch adds FVD's implementation of the bdrv_has_zero_init() interface.
Signed-off-by: Chunqiang Tang <ct...@us.ibm.com>
---
block/fvd-misc.c | 9 ++++++++-
1 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/block/fvd-misc.c b/block/fvd-misc.c
index 766b62b..61e39bb 100644
--- a/block/fvd-misc.c
+++ b/block/fvd-misc.c
@@ -341,5 +341,12 @@ static int fvd_get_info(BlockDriverState * bs,
BlockDriverInfo * bdi)
static int fvd_has_zero_init(BlockDriverState * bs)
{
- return 0;
+ BDRVFvdState *s = bs->opaque;
+
+ /* For a non-compact image, chunks_relocated is always false. For a
+ * compact image with chunks_relocated=true, it can no longer guarantee
+ * zero init even if the file system does that. This is because a partialy
+ * written chunk X may be relocated to a location previously used by
+ * another chunk Y and some garbage data are left there by Y. */
+ return s->chunks_relocated ? 0 : bdrv_has_zero_init(s->fvd_data);
}
--
1.7.0.4
