diff mbox

[12/21] qcow2: Allow creation with refcount order != 4

Message ID 1415627159-15941-13-git-send-email-mreitz@redhat.com
State New
Headers show

Commit Message

Max Reitz Nov. 10, 2014, 1:45 p.m. UTC 
Add a creation option to qcow2 for setting the refcount order of images
to be created, and respect that option's value.

This breaks some test outputs, fix them.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/qcow2.c              |  20 ++++++++
 include/block/block_int.h  |   1 +
 tests/qemu-iotests/049.out | 112 ++++++++++++++++++++++-----------------------
 tests/qemu-iotests/079.out |  18 ++++----
 tests/qemu-iotests/082.out |  41 ++++++++++++++---
 tests/qemu-iotests/085.out |  38 +++++++--------
 6 files changed, 139 insertions(+), 91 deletions(-)

Comments

Eric Blake Nov. 11, 2014, 6:05 p.m. UTC | #1 
On 11/10/2014 06:45 AM, Max Reitz wrote:
> Add a creation option to qcow2 for setting the refcount order of images
> to be created, and respect that option's value.
> 
> This breaks some test outputs, fix them.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  block/qcow2.c              |  20 ++++++++
>  include/block/block_int.h  |   1 +
>  tests/qemu-iotests/049.out | 112 ++++++++++++++++++++++-----------------------
>  tests/qemu-iotests/079.out |  18 ++++----
>  tests/qemu-iotests/082.out |  41 ++++++++++++++---
>  tests/qemu-iotests/085.out |  38 +++++++--------
>  6 files changed, 139 insertions(+), 91 deletions(-)

Is there any .json file that needs to be modified to allow this option
to be set via QMP?  I guess that can be a followup.

>  qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- 1kilobyte
> -qemu-img: Invalid image size specified! You may use k, M, G, T, P or E suffixes for 
> +qemu-img: Invalid image size specified! You may use k, M, G, T, P or E suffixes for
>  qemu-img: kilobytes, megabytes, gigabytes, terabytes, petabytes and exabytes.

Nice that you are also getting rid of trailing whitespace.

Reviewed-by: Eric Blake <eblake@redhat.com>
Max Reitz Nov. 12, 2014, 8:47 a.m. UTC | #2 
On 2014-11-11 at 19:05, Eric Blake wrote:
> On 11/10/2014 06:45 AM, Max Reitz wrote:
>> Add a creation option to qcow2 for setting the refcount order of images
>> to be created, and respect that option's value.
>>
>> This breaks some test outputs, fix them.
>>
>> Signed-off-by: Max Reitz <mreitz@redhat.com>
>> ---
>>   block/qcow2.c              |  20 ++++++++
>>   include/block/block_int.h  |   1 +
>>   tests/qemu-iotests/049.out | 112 ++++++++++++++++++++++-----------------------
>>   tests/qemu-iotests/079.out |  18 ++++----
>>   tests/qemu-iotests/082.out |  41 ++++++++++++++---
>>   tests/qemu-iotests/085.out |  38 +++++++--------
>>   6 files changed, 139 insertions(+), 91 deletions(-)
> Is there any .json file that needs to be modified to allow this option
> to be set via QMP?  I guess that can be a followup.

Good point, but I can't find any JSON object which contains a 
"lazy-refcounts" (or "lazy_refcounts") field and which seems to be 
related to image creation (if "lazy-refcounts" is somewhere not relating 
to options for opening an existing image, "refcount-width" should be 
there, too). I guess there probably is no way of directly creating an 
image over QMP yet at all.

>>   qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- 1kilobyte
>> -qemu-img: Invalid image size specified! You may use k, M, G, T, P or E suffixes for
>> +qemu-img: Invalid image size specified! You may use k, M, G, T, P or E suffixes for
>>   qemu-img: kilobytes, megabytes, gigabytes, terabytes, petabytes and exabytes.
> Nice that you are also getting rid of trailing whitespace.

That was actually unintentional. You seem fine with it, though, so I'll 
remove all trailing whitespace in all the test outputs I'm touching in v2.

Max

> Reviewed-by: Eric Blake <eblake@redhat.com>
diff mbox

Patch

diff --git a/block/qcow2.c b/block/qcow2.c
index 9accd88..5ec9e34 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2065,6 +2065,17 @@  static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
         goto finish;
     }
 
+    refcount_width = qemu_opt_get_number_del(opts, BLOCK_OPT_REFCOUNT_WIDTH,
+                                             refcount_width);
+    if (refcount_width <= 0 || refcount_width > 64 ||
+        !is_power_of_2(refcount_width))
+    {
+        error_setg(errp, "Refcount width must be a power of two and may not "
+                   "exceed 64 bits");
+        ret = -EINVAL;
+        goto finish;
+    }
+
     if (version < 3 && refcount_width != 16) {
         error_setg(errp, "Different refcount widths than 16 bits require "
                    "compatibility level 1.1 or above (use compat=1.1 or "
@@ -2704,6 +2715,9 @@  static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
         } else if (!strcmp(desc->name, "lazy_refcounts")) {
             lazy_refcounts = qemu_opt_get_bool(opts, "lazy_refcounts",
                                                lazy_refcounts);
+        } else if (!strcmp(desc->name, "refcount_width")) {
+            error_report("Cannot change refcount entry width");
+            return -ENOTSUP;
         } else {
             /* if this assertion fails, this probably means a new option was
              * added without having it covered here */
@@ -2873,6 +2887,12 @@  static QemuOptsList qcow2_create_opts = {
             .help = "Postpone refcount updates",
             .def_value_str = "off"
         },
+        {
+            .name = BLOCK_OPT_REFCOUNT_WIDTH,
+            .type = QEMU_OPT_NUMBER,
+            .help = "Width of a reference count entry in bits",
+            .def_value_str = "16"
+        },
         { /* end of list */ }
     }
 };
diff --git a/include/block/block_int.h b/include/block/block_int.h
index a1c17b9..c34d610 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -56,6 +56,7 @@ 
 #define BLOCK_OPT_ADAPTER_TYPE      "adapter_type"
 #define BLOCK_OPT_REDUNDANCY        "redundancy"
 #define BLOCK_OPT_NOCOW             "nocow"
+#define BLOCK_OPT_REFCOUNT_WIDTH    "refcount_width"
 
 typedef struct BdrvTrackedRequest {
     BlockDriverState *bs;
diff --git a/tests/qemu-iotests/049.out b/tests/qemu-iotests/049.out
index 09ca0ae..9369c12 100644
--- a/tests/qemu-iotests/049.out
+++ b/tests/qemu-iotests/049.out
@@ -4,90 +4,90 @@  QA output created by 049
 == 1. Traditional size parameter ==
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1024
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1024b
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1k
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1K
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1048576 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1048576 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1G
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1073741824 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1073741824 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1T
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1099511627776 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1099511627776 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1024.0
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1024.0b
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5k
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5K
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1572864 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1572864 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5G
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1610612736 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1610612736 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 1.5T
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1649267441664 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1649267441664 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 == 2. Specifying size via -o ==
 
 qemu-img create -f qcow2 -o size=1024 TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o size=1024b TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o size=1k TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o size=1K TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o size=1M TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1048576 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1048576 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o size=1G TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1073741824 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1073741824 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o size=1T TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1099511627776 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1099511627776 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o size=1024.0 TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o size=1024.0b TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o size=1.5k TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o size=1.5K TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1536 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o size=1.5M TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1572864 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1572864 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o size=1.5G TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1610612736 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1610612736 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o size=1.5T TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1649267441664 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1649267441664 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 == 3. Invalid sizes ==
 
@@ -97,7 +97,7 @@  qemu-img: Image size must be less than 8 EiB!
 qemu-img create -f qcow2 -o size=-1024 TEST_DIR/t.qcow2
 qemu-img: qcow2 doesn't support shrinking images yet
 qemu-img: TEST_DIR/t.qcow2: Could not resize image: Operation not supported
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=-1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=-1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- -1k
 qemu-img: Image size must be less than 8 EiB!
@@ -105,17 +105,17 @@  qemu-img: Image size must be less than 8 EiB!
 qemu-img create -f qcow2 -o size=-1k TEST_DIR/t.qcow2
 qemu-img: qcow2 doesn't support shrinking images yet
 qemu-img: TEST_DIR/t.qcow2: Could not resize image: Operation not supported
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=-1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=-1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- 1kilobyte
-qemu-img: Invalid image size specified! You may use k, M, G, T, P or E suffixes for 
+qemu-img: Invalid image size specified! You may use k, M, G, T, P or E suffixes for
 qemu-img: kilobytes, megabytes, gigabytes, terabytes, petabytes and exabytes.
 
 qemu-img create -f qcow2 -o size=1kilobyte TEST_DIR/t.qcow2
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- foobar
-qemu-img: Invalid image size specified! You may use k, M, G, T, P or E suffixes for 
+qemu-img: Invalid image size specified! You may use k, M, G, T, P or E suffixes for
 qemu-img: kilobytes, megabytes, gigabytes, terabytes, petabytes and exabytes.
 
 qemu-img create -f qcow2 -o size=foobar TEST_DIR/t.qcow2
@@ -125,84 +125,84 @@  qemu-img: TEST_DIR/t.qcow2: Invalid options for file format 'qcow2'
 == Check correct interpretation of suffixes for cluster size ==
 
 qemu-img create -f qcow2 -o cluster_size=1024 TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o cluster_size=1024b TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o cluster_size=1k TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o cluster_size=1K TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o cluster_size=1M TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1048576 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1048576 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o cluster_size=1024.0 TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o cluster_size=1024.0b TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=1024 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o cluster_size=0.5k TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=512 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=512 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o cluster_size=0.5K TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=512 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=512 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o cluster_size=0.5M TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=524288 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=524288 lazy_refcounts=off refcount_width=16
 
 == Check compat level option ==
 
 qemu-img create -f qcow2 -o compat=0.10 TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='0.10' encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='0.10' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o compat=1.1 TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='1.1' encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='1.1' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o compat=0.42 TEST_DIR/t.qcow2 64M
 qemu-img: TEST_DIR/t.qcow2: Invalid compatibility level: '0.42'
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='0.42' encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='0.42' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o compat=foobar TEST_DIR/t.qcow2 64M
 qemu-img: TEST_DIR/t.qcow2: Invalid compatibility level: 'foobar'
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='foobar' encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='foobar' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 == Check preallocation option ==
 
 qemu-img create -f qcow2 -o preallocation=off TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 preallocation='off' lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 preallocation='off' lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o preallocation=metadata TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 preallocation='metadata' lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 preallocation='metadata' lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o preallocation=1234 TEST_DIR/t.qcow2 64M
 qemu-img: TEST_DIR/t.qcow2: invalid parameter value: 1234
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 preallocation='1234' lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 preallocation='1234' lazy_refcounts=off refcount_width=16
 
 == Check encryption option ==
 
 qemu-img create -f qcow2 -o encryption=off TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o encryption=on TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=on cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 encryption=on cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 == Check lazy_refcounts option (only with v3) ==
 
 qemu-img create -f qcow2 -o compat=1.1,lazy_refcounts=off TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='1.1' encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='1.1' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o compat=1.1,lazy_refcounts=on TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='1.1' encryption=off cluster_size=65536 lazy_refcounts=on 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='1.1' encryption=off cluster_size=65536 lazy_refcounts=on refcount_width=16
 
 qemu-img create -f qcow2 -o compat=0.10,lazy_refcounts=off TEST_DIR/t.qcow2 64M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='0.10' encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='0.10' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o compat=0.10,lazy_refcounts=on TEST_DIR/t.qcow2 64M
 qemu-img: TEST_DIR/t.qcow2: Lazy refcounts only supported with compatibility level 1.1 and above (use compat=1.1 or greater)
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='0.10' encryption=off cluster_size=65536 lazy_refcounts=on 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=67108864 compat='0.10' encryption=off cluster_size=65536 lazy_refcounts=on refcount_width=16
 
 *** done
diff --git a/tests/qemu-iotests/079.out b/tests/qemu-iotests/079.out
index ef4b8c9..8443762 100644
--- a/tests/qemu-iotests/079.out
+++ b/tests/qemu-iotests/079.out
@@ -2,31 +2,31 @@  QA output created by 079
 === Check option preallocation and cluster_size ===
 
 qemu-img create -f qcow2 -o preallocation=metadata,cluster_size=16384 TEST_DIR/t.qcow2 4G
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=16384 preallocation='metadata' lazy_refcounts=off
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=16384 preallocation='metadata' lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o preallocation=metadata,cluster_size=32768 TEST_DIR/t.qcow2 4G
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=32768 preallocation='metadata' lazy_refcounts=off
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=32768 preallocation='metadata' lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o preallocation=metadata,cluster_size=65536 TEST_DIR/t.qcow2 4G
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=65536 preallocation='metadata' lazy_refcounts=off
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=65536 preallocation='metadata' lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o preallocation=metadata,cluster_size=131072 TEST_DIR/t.qcow2 4G
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=131072 preallocation='metadata' lazy_refcounts=off
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=131072 preallocation='metadata' lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o preallocation=metadata,cluster_size=262144 TEST_DIR/t.qcow2 4G
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=262144 preallocation='metadata' lazy_refcounts=off
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=262144 preallocation='metadata' lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o preallocation=metadata,cluster_size=524288 TEST_DIR/t.qcow2 4G
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=524288 preallocation='metadata' lazy_refcounts=off
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=524288 preallocation='metadata' lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o preallocation=metadata,cluster_size=1048576 TEST_DIR/t.qcow2 4G
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=1048576 preallocation='metadata' lazy_refcounts=off
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=1048576 preallocation='metadata' lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o preallocation=metadata,cluster_size=2097152 TEST_DIR/t.qcow2 4G
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=2097152 preallocation='metadata' lazy_refcounts=off
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=2097152 preallocation='metadata' lazy_refcounts=off refcount_width=16
 
 qemu-img create -f qcow2 -o preallocation=metadata,cluster_size=4194304 TEST_DIR/t.qcow2 4G
 qemu-img: TEST_DIR/t.qcow2: Cluster size must be a power of two between 512 and 2048k
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=4194304 preallocation='metadata' lazy_refcounts=off
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=4294967296 encryption=off cluster_size=4194304 preallocation='metadata' lazy_refcounts=off refcount_width=16
 
 *** done
diff --git a/tests/qemu-iotests/082.out b/tests/qemu-iotests/082.out
index 4b14b4f..dc8bdd3 100644
--- a/tests/qemu-iotests/082.out
+++ b/tests/qemu-iotests/082.out
@@ -3,14 +3,14 @@  QA output created by 082
 === create: Options specified more than once ===
 
 Testing: create -f foo -f qcow2 TEST_DIR/t.qcow2 128M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 image: TEST_DIR/t.IMGFMT
 file format: IMGFMT
 virtual size: 128M (134217728 bytes)
 cluster_size: 65536
 
 Testing: create -f qcow2 -o cluster_size=4k -o lazy_refcounts=on TEST_DIR/t.qcow2 128M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 encryption=off cluster_size=4096 lazy_refcounts=on 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 encryption=off cluster_size=4096 lazy_refcounts=on refcount_width=16
 
 Testing: info TEST_DIR/t.qcow2
 image: TEST_DIR/t.qcow2
@@ -25,7 +25,7 @@  Format specific information:
     corrupt: false
 
 Testing: create -f qcow2 -o cluster_size=4k -o lazy_refcounts=on -o cluster_size=8k TEST_DIR/t.qcow2 128M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 encryption=off cluster_size=8192 lazy_refcounts=on 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 encryption=off cluster_size=8192 lazy_refcounts=on refcount_width=16
 
 Testing: info TEST_DIR/t.qcow2
 image: TEST_DIR/t.qcow2
@@ -40,7 +40,7 @@  Format specific information:
     corrupt: false
 
 Testing: create -f qcow2 -o cluster_size=4k,cluster_size=8k TEST_DIR/t.qcow2 128M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 encryption=off cluster_size=8192 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 encryption=off cluster_size=8192 lazy_refcounts=off refcount_width=16
 image: TEST_DIR/t.IMGFMT
 file format: IMGFMT
 virtual size: 128M (134217728 bytes)
@@ -58,6 +58,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: create -f qcow2 -o ? TEST_DIR/t.qcow2 128M
@@ -70,6 +71,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: create -f qcow2 -o cluster_size=4k,help TEST_DIR/t.qcow2 128M
@@ -82,6 +84,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: create -f qcow2 -o cluster_size=4k,? TEST_DIR/t.qcow2 128M
@@ -94,6 +97,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: create -f qcow2 -o help,cluster_size=4k TEST_DIR/t.qcow2 128M
@@ -106,6 +110,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: create -f qcow2 -o ?,cluster_size=4k TEST_DIR/t.qcow2 128M
@@ -118,6 +123,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: create -f qcow2 -o cluster_size=4k -o help TEST_DIR/t.qcow2 128M
@@ -130,6 +136,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: create -f qcow2 -o cluster_size=4k -o ? TEST_DIR/t.qcow2 128M
@@ -142,13 +149,14 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: create -f qcow2 -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2 128M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/t.qcow2,help' encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/t.qcow2,help' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 Testing: create -f qcow2 -o backing_file=TEST_DIR/t.qcow2,,? TEST_DIR/t.qcow2 128M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/t.qcow2,?' encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/t.qcow2,?' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 Testing: create -f qcow2 -o backing_file=TEST_DIR/t.qcow2, -o help TEST_DIR/t.qcow2 128M
 qemu-img: Invalid option list: backing_file=TEST_DIR/t.qcow2,
@@ -169,6 +177,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 
 Testing: create -o help
 Supported options:
@@ -177,7 +186,7 @@  size             Virtual disk size
 === convert: Options specified more than once ===
 
 Testing: create -f qcow2 TEST_DIR/t.qcow2 128M
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 encryption=off cluster_size=65536 lazy_refcounts=off 
+Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=134217728 encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 
 Testing: convert -f foo -f qcow2 TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
 image: TEST_DIR/t.IMGFMT.base
@@ -236,6 +245,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: convert -O qcow2 -o ? TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -248,6 +258,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: convert -O qcow2 -o cluster_size=4k,help TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -260,6 +271,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: convert -O qcow2 -o cluster_size=4k,? TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -272,6 +284,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: convert -O qcow2 -o help,cluster_size=4k TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -284,6 +297,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: convert -O qcow2 -o ?,cluster_size=4k TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -296,6 +310,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: convert -O qcow2 -o cluster_size=4k -o help TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -308,6 +323,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: convert -O qcow2 -o cluster_size=4k -o ? TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -320,6 +336,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: convert -O qcow2 -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2 TEST_DIR/t.qcow2.base
@@ -347,6 +364,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 
 Testing: convert -o help
 Supported options:
@@ -414,6 +432,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: amend -f qcow2 -o ? TEST_DIR/t.qcow2
@@ -426,6 +445,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: amend -f qcow2 -o cluster_size=4k,help TEST_DIR/t.qcow2
@@ -438,6 +458,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: amend -f qcow2 -o cluster_size=4k,? TEST_DIR/t.qcow2
@@ -450,6 +471,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: amend -f qcow2 -o help,cluster_size=4k TEST_DIR/t.qcow2
@@ -462,6 +484,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: amend -f qcow2 -o ?,cluster_size=4k TEST_DIR/t.qcow2
@@ -474,6 +497,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: amend -f qcow2 -o cluster_size=4k -o help TEST_DIR/t.qcow2
@@ -486,6 +510,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: amend -f qcow2 -o cluster_size=4k -o ? TEST_DIR/t.qcow2
@@ -498,6 +523,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 nocow            Turn off copy-on-write (valid only on btrfs)
 
 Testing: amend -f qcow2 -o backing_file=TEST_DIR/t.qcow2,,help TEST_DIR/t.qcow2
@@ -527,6 +553,7 @@  encryption       Encrypt the image
 cluster_size     qcow2 cluster size
 preallocation    Preallocation mode (allowed values: off, metadata, falloc, full)
 lazy_refcounts   Postpone refcount updates
+refcount_width   Width of a reference count entry in bits
 
 Testing: convert -o help
 Supported options:
diff --git a/tests/qemu-iotests/085.out b/tests/qemu-iotests/085.out
index 0f2b17f..2e86fb7 100644
--- a/tests/qemu-iotests/085.out
+++ b/tests/qemu-iotests/085.out
@@ -11,7 +11,7 @@  Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728
 
 === Create a single snapshot on virtio0 ===
 
-Formatting 'TEST_DIR/1-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/t.qcow2.orig' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
+Formatting 'TEST_DIR/1-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/t.qcow2.orig' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 {"return": {}}
 
 === Invalid command - missing device and nodename ===
@@ -25,31 +25,31 @@  Formatting 'TEST_DIR/1-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file
 
 === Create several transactional group snapshots ===
 
-Formatting 'TEST_DIR/2-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/1-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
-Formatting 'TEST_DIR/2-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/t.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
+Formatting 'TEST_DIR/2-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/1-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
+Formatting 'TEST_DIR/2-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/t.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 {"return": {}}
-Formatting 'TEST_DIR/3-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/2-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
-Formatting 'TEST_DIR/3-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/2-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
+Formatting 'TEST_DIR/3-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/2-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
+Formatting 'TEST_DIR/3-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/2-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 {"return": {}}
-Formatting 'TEST_DIR/4-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/3-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
-Formatting 'TEST_DIR/4-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/3-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
+Formatting 'TEST_DIR/4-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/3-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
+Formatting 'TEST_DIR/4-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/3-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 {"return": {}}
-Formatting 'TEST_DIR/5-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/4-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
-Formatting 'TEST_DIR/5-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/4-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
+Formatting 'TEST_DIR/5-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/4-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
+Formatting 'TEST_DIR/5-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/4-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 {"return": {}}
-Formatting 'TEST_DIR/6-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/5-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
-Formatting 'TEST_DIR/6-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/5-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
+Formatting 'TEST_DIR/6-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/5-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
+Formatting 'TEST_DIR/6-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/5-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 {"return": {}}
-Formatting 'TEST_DIR/7-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/6-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
-Formatting 'TEST_DIR/7-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/6-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
+Formatting 'TEST_DIR/7-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/6-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
+Formatting 'TEST_DIR/7-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/6-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 {"return": {}}
-Formatting 'TEST_DIR/8-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/7-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
-Formatting 'TEST_DIR/8-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/7-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
+Formatting 'TEST_DIR/8-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/7-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
+Formatting 'TEST_DIR/8-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/7-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 {"return": {}}
-Formatting 'TEST_DIR/9-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/8-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
-Formatting 'TEST_DIR/9-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/8-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
+Formatting 'TEST_DIR/9-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/8-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
+Formatting 'TEST_DIR/9-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/8-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 {"return": {}}
-Formatting 'TEST_DIR/10-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/9-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
-Formatting 'TEST_DIR/10-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/9-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off
+Formatting 'TEST_DIR/10-snapshot-v0.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/9-snapshot-v0.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
+Formatting 'TEST_DIR/10-snapshot-v1.qcow2', fmt=qcow2 size=134217728 backing_file='TEST_DIR/9-snapshot-v1.qcow2' backing_fmt='qcow2' encryption=off cluster_size=65536 lazy_refcounts=off refcount_width=16
 {"return": {}}
 *** done