From c1f5bafd70a8d9366570a3de472ef108415cd631 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 4 Mar 2013 15:02:32 +0100 Subject: [PATCH] qcow2: set L2 cache dependency in qcow2_alloc_bytes() Compressed writes use qcow2_alloc_bytes() to allocate space with byte granularity. The affected clusters' refcounts will be incremented but we do not need to flush yet. Set a L2 cache dependency on the refcount block cache, so that the refcounts get written out before the L2 updates. Signed-off-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- block/qcow2-refcount.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index e8b5d0a4ac..4d9df5fe95 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -669,7 +669,11 @@ int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) } } - bdrv_flush(bs->file); + /* The cluster refcount was incremented, either by qcow2_alloc_clusters() + * or explicitly by update_cluster_refcount(). Refcount blocks must be + * flushed before the caller's L2 table updates. + */ + qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache); return offset; }