qcow2: Add refcount_bits to format-specific info

Add the bit width of every refcount entry to the format-specific
information.

In contrast to lazy_refcounts and the corrupt flag, this should be
always emitted, even for compat=0.10 although it does not support any
refcount width other than 16 bits. This is because if a boolean is
optional, one normally assumes it to be false when omitted; but if an
integer is not specified, it is rather difficult to guess its value.

This new field breaks some test outputs, fix them.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/qcow2.c

@@ -2482,7 +2482,8 @@ static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs)
     };
     if (s->qcow_version == 2) {
         *spec_info->qcow2 = (ImageInfoSpecificQCow2){
-            .compat = g_strdup("0.10"),
+            .compat             = g_strdup("0.10"),
+            .refcount_bits      = s->refcount_bits,
         };
     } else if (s->qcow_version == 3) {
         *spec_info->qcow2 = (ImageInfoSpecificQCow2){
@@ -2493,6 +2494,7 @@ static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs)
             .corrupt            = s->incompatible_features &
                                   QCOW2_INCOMPAT_CORRUPT,
             .has_corrupt        = true,
+            .refcount_bits      = s->refcount_bits,
         };
     }
 

qapi/block-core.json

@@ -41,13 +41,16 @@
 # @corrupt: #optional true if the image has been marked corrupt; only valid for
 #           compat >= 1.1 (since 2.2)
 #
+# @refcount-bits: width of a refcount entry in bits (since 2.3)
+#
 # Since: 1.7
 ##
 { 'type': 'ImageInfoSpecificQCow2',
   'data': {
       'compat': 'str',
       '*lazy-refcounts': 'bool',
-      '*corrupt': 'bool'
+      '*corrupt': 'bool',
+      'refcount-bits': 'int'
   } }
 
 ##

tests/qemu-iotests/060.out

@@ -18,6 +18,7 @@ cluster_size: 65536
 Format specific information:
     compat: 1.1
     lazy refcounts: false
+    refcount bits: 16
     corrupt: true
 qemu-io: can't open device TEST_DIR/t.IMGFMT: IMGFMT: Image is corrupt; cannot be opened read/write
 read 512/512 bytes at offset 0

tests/qemu-iotests/065

@@ -88,34 +88,41 @@ class TestQMP(TestImageInfoSpecific):
 class TestQCow2(TestQemuImgInfo):
     '''Testing a qcow2 version 2 image'''
     img_options = 'compat=0.10'
-    json_compare = { 'compat': '0.10' }
+    json_compare = { 'compat': '0.10', 'refcount-bits': 16 }
-    human_compare = [ 'compat: 0.10' ]
+    human_compare = [ 'compat: 0.10', 'refcount bits: 16' ]
 
 class TestQCow3NotLazy(TestQemuImgInfo):
     '''Testing a qcow2 version 3 image with lazy refcounts disabled'''
     img_options = 'compat=1.1,lazy_refcounts=off'
-    json_compare = { 'compat': '1.1', 'lazy-refcounts': False, 'corrupt': False }
+    json_compare = { 'compat': '1.1', 'lazy-refcounts': False,
-    human_compare = [ 'compat: 1.1', 'lazy refcounts: false', 'corrupt: false' ]
+                     'refcount-bits': 16, 'corrupt': False }
+    human_compare = [ 'compat: 1.1', 'lazy refcounts: false',
+                      'refcount bits: 16', 'corrupt: false' ]
 
 class TestQCow3Lazy(TestQemuImgInfo):
     '''Testing a qcow2 version 3 image with lazy refcounts enabled'''
     img_options = 'compat=1.1,lazy_refcounts=on'
-    json_compare = { 'compat': '1.1', 'lazy-refcounts': True, 'corrupt': False }
+    json_compare = { 'compat': '1.1', 'lazy-refcounts': True,
-    human_compare = [ 'compat: 1.1', 'lazy refcounts: true', 'corrupt: false' ]
+                     'refcount-bits': 16, 'corrupt': False }
+    human_compare = [ 'compat: 1.1', 'lazy refcounts: true',
+                      'refcount bits: 16', 'corrupt: false' ]
 
 class TestQCow3NotLazyQMP(TestQMP):
     '''Testing a qcow2 version 3 image with lazy refcounts disabled, opening
        with lazy refcounts enabled'''
     img_options = 'compat=1.1,lazy_refcounts=off'
     qemu_options = 'lazy-refcounts=on'
-    compare = { 'compat': '1.1', 'lazy-refcounts': False, 'corrupt': False }
+    compare = { 'compat': '1.1', 'lazy-refcounts': False,
+                'refcount-bits': 16, 'corrupt': False }
+
 
 class TestQCow3LazyQMP(TestQMP):
     '''Testing a qcow2 version 3 image with lazy refcounts enabled, opening
        with lazy refcounts disabled'''
     img_options = 'compat=1.1,lazy_refcounts=on'
     qemu_options = 'lazy-refcounts=off'
-    compare = { 'compat': '1.1', 'lazy-refcounts': True, 'corrupt': False }
+    compare = { 'compat': '1.1', 'lazy-refcounts': True,
+                'refcount-bits': 16, 'corrupt': False }
 
 TestImageInfoSpecific = None
 TestQemuImgInfo = None

tests/qemu-iotests/067.out

@@ -32,6 +32,7 @@ Testing: -drive file=TEST_DIR/t.qcow2,format=qcow2,if=none,id=disk -device virti
                         "data": {
                             "compat": "1.1",
                             "lazy-refcounts": false,
+                            "refcount-bits": 16,
                             "corrupt": false
                         }
                     },
@@ -208,6 +209,7 @@ Testing: -drive file=TEST_DIR/t.qcow2,format=qcow2,if=none,id=disk
                         "data": {
                             "compat": "1.1",
                             "lazy-refcounts": false,
+                            "refcount-bits": 16,
                             "corrupt": false
                         }
                     },
@@ -414,6 +416,7 @@ Testing:
                         "data": {
                             "compat": "1.1",
                             "lazy-refcounts": false,
+                            "refcount-bits": 16,
                             "corrupt": false
                         }
                     },
@@ -599,6 +602,7 @@ Testing:
                         "data": {
                             "compat": "1.1",
                             "lazy-refcounts": false,
+                            "refcount-bits": 16,
                             "corrupt": false
                         }
                     },
@@ -710,6 +714,7 @@ Testing:
                         "data": {
                             "compat": "1.1",
                             "lazy-refcounts": false,
+                            "refcount-bits": 16,
                             "corrupt": false
                         }
                     },

tests/qemu-iotests/082.out

@@ -18,6 +18,7 @@ cluster_size: 4096
 Format specific information:
     compat: 1.1
     lazy refcounts: true
+    refcount bits: 16
     corrupt: false
 
 Testing: create -f qcow2 -o cluster_size=4k -o lazy_refcounts=on -o cluster_size=8k TEST_DIR/t.qcow2 128M
@@ -29,6 +30,7 @@ cluster_size: 8192
 Format specific information:
     compat: 1.1
     lazy refcounts: true
+    refcount bits: 16
     corrupt: false
 
 Testing: create -f qcow2 -o cluster_size=4k,cluster_size=8k TEST_DIR/t.qcow2 128M
@@ -190,6 +192,7 @@ cluster_size: 4096
 Format specific information:
     compat: 1.1
     lazy refcounts: true
+    refcount bits: 16
     corrupt: false
 
 Testing: convert -O qcow2 -o cluster_size=4k -o lazy_refcounts=on -o cluster_size=8k TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -200,6 +203,7 @@ cluster_size: 8192
 Format specific information:
     compat: 1.1
     lazy refcounts: true
+    refcount bits: 16
     corrupt: false
 
 Testing: convert -O qcow2 -o cluster_size=4k,cluster_size=8k TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -346,6 +350,7 @@ cluster_size: 65536
 Format specific information:
     compat: 1.1
     lazy refcounts: true
+    refcount bits: 16
     corrupt: false
 
 Testing: amend -f qcow2 -o size=130M -o lazy_refcounts=off TEST_DIR/t.qcow2
@@ -356,6 +361,7 @@ cluster_size: 65536
 Format specific information:
     compat: 1.1
     lazy refcounts: false
+    refcount bits: 16
     corrupt: false
 
 Testing: amend -f qcow2 -o size=8M -o lazy_refcounts=on -o size=132M TEST_DIR/t.qcow2
@@ -366,6 +372,7 @@ cluster_size: 65536
 Format specific information:
     compat: 1.1
     lazy refcounts: true
+    refcount bits: 16
     corrupt: false
 
 Testing: amend -f qcow2 -o size=4M,size=148M TEST_DIR/t.qcow2

tests/qemu-iotests/089.out

@@ -43,6 +43,7 @@ vm state offset: 512 MiB
 Format specific information:
     compat: 1.1
     lazy refcounts: false
+    refcount bits: 16
     corrupt: false
 format name: IMGFMT
 cluster size: 64 KiB
@@ -50,5 +51,6 @@ vm state offset: 512 MiB
 Format specific information:
     compat: 1.1
     lazy refcounts: false
+    refcount bits: 16
     corrupt: false
 *** done