On 09/17/2010 11:18 AM, Kevin Wolf wrote:
Note that the flush is omitted intentionally in qcow2_free_clusters. If
anything, we can leak clusters here if we lose the writes.
Signed-off-by: Kevin Wolf<kw...@redhat.com>
Cluster leaking gets picked up by bdrv_check though, right?
I think I've convinced myself that leaking clusters is not an acceptable
behavior from a security perspective but as long as it's detectable via
bdrv_check, qcow2 could implement an online check to address it.
Regards,
Anthony Liguori
---
block/qcow2-refcount.c | 13 +++++++++++--
1 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 7dc75d1..4fc3f80 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -261,6 +261,8 @@ static int64_t alloc_refcount_block(BlockDriverState *bs,
int64_t cluster_index)
goto fail_block;
}
+ bdrv_flush(bs->file);
+
/* Initialize the new refcount block only after updating its refcount,
* update_refcount uses the refcount cache itself */
memset(s->refcount_block_cache, 0, s->cluster_size);
@@ -551,8 +553,6 @@ fail:
dummy = update_refcount(bs, offset, cluster_offset - offset, -addend);
}
- bdrv_flush(bs->file);
-
return ret;
}
@@ -575,6 +575,8 @@ static int update_cluster_refcount(BlockDriverState *bs,
return ret;
}
+ bdrv_flush(bs->file);
+
return get_refcount(bs, cluster_index);
}
@@ -626,6 +628,9 @@ int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t
size)
if (ret< 0) {
return ret;
}
+
+ bdrv_flush(bs->file);
+
return offset;
}
@@ -803,6 +808,10 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
if (ret< 0) {
goto fail;
}
+
+ /* TODO Flushing once for the whole function should
+ * be enough */
+ bdrv_flush(bs->file);
}
/* compressed clusters are never modified */
refcount = 2;