qcow2: Write full header on image creation

When creating a qcow2 image, we didn't necessarily call
qcow2_update_header(), but could end up with the basic header that
qcow2_create2() created manually. One thing that this basic header
lacks is the feature table. Let's make sure that it's always present.

This requires a few updates to test cases as well.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

block/qcow2.c

@@ -2239,6 +2239,13 @@ static int qcow2_create2(const char *filename, int64_t total_size,
         abort();
     }
 
+    /* Create a full header (including things like feature table) */
+    ret = qcow2_update_header(bs);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "Could not update qcow2 header");
+        goto out;
+    }
+
     /* Okay, now that we have a valid image, let's give it the right size */
     ret = bdrv_truncate(bs, total_size);
     if (ret < 0) {

tests/qemu-iotests/031.out

@@ -115,6 +115,11 @@ autoclear_features        0x0
 refcount_order            4
 header_length             104
 
+Header extension:
+magic                     0x6803f857
+length                    144
+data                      <binary>
+
 Header extension:
 magic                     0x12345678
 length                    31

tests/qemu-iotests/036

@@ -57,6 +57,7 @@ _make_test_img 64M
 $PYTHON qcow2.py "$TEST_IMG" set-feature-bit incompatible 63
 
 # Without feature table
+$PYTHON qcow2.py "$TEST_IMG" del-header-ext 0x6803f857
 $PYTHON qcow2.py "$TEST_IMG" dump-header
 _img_info
 
@@ -73,6 +74,7 @@ $PYTHON qcow2.py "$TEST_IMG" set-feature-bit incompatible 62
 $PYTHON qcow2.py "$TEST_IMG" set-feature-bit incompatible 63
 
 # Without feature table
+$PYTHON qcow2.py "$TEST_IMG" del-header-ext 0x6803f857
 _img_info
 
 # With feature table containing bit 63

tests/qemu-iotests/036.out

@@ -56,6 +56,11 @@ autoclear_features        0x8000000000000000
 refcount_order            4
 header_length             104
 
+Header extension:
+magic                     0x6803f857
+length                    144
+data                      <binary>
+
 
 === Repair image ===
 

tests/qemu-iotests/061.out

@@ -24,6 +24,11 @@ autoclear_features        0x0
 refcount_order            4
 header_length             104
 
+Header extension:
+magic                     0x6803f857
+length                    144
+data                      <binary>
+
 magic                     0x514649fb
 version                   2
 backing_file_offset       0x0
@@ -76,6 +81,11 @@ autoclear_features        0x0
 refcount_order            4
 header_length             104
 
+Header extension:
+magic                     0x6803f857
+length                    144
+data                      <binary>
+
 ERROR cluster 5 refcount=0 reference=1
 ERROR cluster 6 refcount=0 reference=1
 Rebuilding refcount structure
@@ -126,6 +136,11 @@ autoclear_features        0x40000000000
 refcount_order            4
 header_length             104
 
+Header extension:
+magic                     0x6803f857
+length                    144
+data                      <binary>
+
 magic                     0x514649fb
 version                   2
 backing_file_offset       0x0
@@ -228,6 +243,11 @@ autoclear_features        0x0
 refcount_order            4
 header_length             104
 
+Header extension:
+magic                     0x6803f857
+length                    144
+data                      <binary>
+
 ERROR cluster 5 refcount=0 reference=1
 ERROR cluster 6 refcount=0 reference=1
 Rebuilding refcount structure