qcow2: Basic definitions for external data files
This adds basic constants, struct fields and helper function for
external data file support to the implementation.
QCOW2_INCOMPAT_MASK and QCOW2_AUTOCLEAR_MASK are not updated yet so that
opening images with an external data file still fails (we don't handle
them correctly yet).
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/qcow2.c b/block/qcow2.c
index 9489d79..59cf706 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -73,6 +73,7 @@
#define QCOW2_EXT_MAGIC_FEATURE_TABLE 0x6803f857
#define QCOW2_EXT_MAGIC_CRYPTO_HEADER 0x0537be77
#define QCOW2_EXT_MAGIC_BITMAPS 0x23852875
+#define QCOW2_EXT_MAGIC_DATA_FILE 0x44415441
static int coroutine_fn
qcow2_co_preadv_compressed(BlockDriverState *bs,
@@ -1452,6 +1453,9 @@
goto fail;
}
+ /* TODO Open external data file */
+ s->data_file = bs->file;
+
/* qcow2_read_extension may have set up the crypto context
* if the crypt method needs a header region, some methods
* don't need header extensions, so must check here
@@ -2441,6 +2445,11 @@
.name = "corrupt bit",
},
{
+ .type = QCOW2_FEAT_TYPE_INCOMPATIBLE,
+ .bit = QCOW2_INCOMPAT_DATA_FILE_BITNR,
+ .name = "external data file",
+ },
+ {
.type = QCOW2_FEAT_TYPE_COMPATIBLE,
.bit = QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
.name = "lazy refcounts",
