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authorMax Reitz <mreitz@redhat.com>2015-06-01 18:09:17 +0200
committerKevin Wolf <kwolf@redhat.com>2015-06-12 15:54:00 +0200
commit57e216695948a79d9ced82fc217a37cce70fd986 (patch)
treeacb4be45e3f02865206410239b5424b2fcb21bf6 /block/qcow2.h
parent9aa711d75030356f1e179b9f71780da5fd1a45bb (diff)
qcow2: Set MIN_L2_CACHE_SIZE to 2
The L2 cache must cover at least two L2 tables, because during COW two L2 tables are accessed simultaneously. Reported-by: Alexander Graf <agraf@suse.de> Cc: qemu-stable <qemu-stable@nongnu.org> Signed-off-by: Max Reitz <mreitz@redhat.com> Tested-by: Alexander Graf <agraf@suse.de> Reviewed-by: Alberto Garcia <berto@igalia.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/qcow2.h')
-rw-r--r--block/qcow2.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/block/qcow2.h b/block/qcow2.h
index 0076512af4..aa200223ce 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -62,7 +62,8 @@
#define MIN_CLUSTER_BITS 9
#define MAX_CLUSTER_BITS 21
-#define MIN_L2_CACHE_SIZE 1 /* cluster */
+/* Must be at least 2 to cover COW */
+#define MIN_L2_CACHE_SIZE 2 /* clusters */
/* Must be at least 4 to cover all cases of refcount table growth */
#define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */