Merge remote-tracking branch 'kwolf/for-anthony' into staging

* kwolf/for-anthony: (38 commits)
  qemu-iotests: Fix test 031 for qcow2 v3 support
  qemu-iotests: Add -o and make v3 the default for qcow2
  qcow2: Zero write support
  qemu-iotests: Test backing file COW with zero clusters
  qemu-iotests: add a simple test for write_zeroes
  qcow2: Support for feature table header extension
  qcow2: Support reading zero clusters
  qcow2: Version 3 images
  qcow2: Ignore reserved bits in check_refcounts
  qcow2: Ignore reserved bits in refcount table entries
  qcow2: Simplify count_cow_clusters
  qcow2: Refactor qcow2_free_any_clusters
  qcow2: Ignore reserved bits in L1/L2 entries
  qcow2: Fail write_compressed when overwriting data
  qcow2: Ignore reserved bits in count_contiguous_clusters()
  qcow2: Ignore reserved bits in get_cluster_offset
  qcow2: Save disk size in snapshot header
  Specification for qcow2 version 3
  qcow2: Fix refcount block allocation during qcow2_alloc_cluster_at()
  iotests: Resolve test failures caused by hostname
  ...

1 files changed, 17 insertions, 7 deletions

diff --git a/tests/qemu-iotests/qcow2.py b/tests/qemu-iotests/qcow2.py
index bfb47e88fc..e27196aa26 100755
--- a/tests/qemu-iotests/qcow2.py
+++ b/tests/qemu-iotests/qcow2.py
@@ -35,6 +35,13 @@ class QcowHeader:
         [ uint32_t, '%d',   'refcount_table_clusters' ],
         [ uint32_t, '%d',   'nb_snapshots' ],
         [ uint64_t, '%#x',  'snapshot_offset' ],
+
+        # Version 3 header fields
+        [ uint64_t, '%#x',  'incompatible_features' ],
+        [ uint64_t, '%#x',  'compatible_features' ],
+        [ uint64_t, '%#x',  'autoclear_features' ],
+        [ uint32_t, '%d',   'refcount_order' ],
+        [ uint32_t, '%d',   'header_length' ],
     ];
 
     fmt = '>' + ''.join(field[0] for field in fields)
@@ -50,9 +57,10 @@ class QcowHeader:
         self.__dict__ = dict((field[2], header[i])
             for i, field in enumerate(QcowHeader.fields))
 
+        self.set_defaults()
         self.cluster_size = 1 << self.cluster_bits
 
-        fd.seek(self.get_header_length())
+        fd.seek(self.header_length)
         self.load_extensions(fd)
 
         if self.backing_file_offset:
@@ -61,11 +69,13 @@ class QcowHeader:
         else:
             self.backing_file = None
 
-    def get_header_length(self):
+    def set_defaults(self):
         if self.version == 2:
-            return 72
-        else:
-            raise Exception("version != 2 not supported")
+            self.incompatible_features = 0
+            self.compatible_features = 0
+            self.autoclear_features = 0
+            self.refcount_order = 4
+            self.header_length = 72
 
     def load_extensions(self, fd):
         self.extensions = []
@@ -86,7 +96,7 @@ class QcowHeader:
 
     def update_extensions(self, fd):
 
-        fd.seek(self.get_header_length())
+        fd.seek(self.header_length)
         extensions = self.extensions
         extensions.append(QcowHeaderExtension(0, 0, ""))
         for ex in extensions:
@@ -103,7 +113,7 @@ class QcowHeader:
 
 
     def update(self, fd):
-        header_bytes = self.get_header_length()
+        header_bytes = self.header_length
 
         self.update_extensions(fd)