qcow2: introduce dirty bit

This patch adds an incompatible feature bit to mark images that have not
been closed cleanly.  When a dirty image file is opened a consistency
check and repair is performed.

Update qemu-iotests 031 and 036 since the extension header size changes
when we add feature bit table entries.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/block/qcow2.h b/block/qcow2.h
index 455b6d7cfe..b5fefc08f7 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -110,6 +110,14 @@ enum {
     QCOW2_FEAT_TYPE_AUTOCLEAR       = 2,
 };
 
+/* Incompatible feature bits */
+enum {
+    QCOW2_INCOMPAT_DIRTY_BITNR   = 0,
+    QCOW2_INCOMPAT_DIRTY         = 1 << QCOW2_INCOMPAT_DIRTY_BITNR,
+
+    QCOW2_INCOMPAT_MASK          = QCOW2_INCOMPAT_DIRTY,
+};
+
 typedef struct Qcow2Feature {
     uint8_t type;
     uint8_t bit;