block/amend: refactor qcow2 amend options

Some qcow2 create options can't be used for amend.
Remove them from the qcow2 create options and add generic logic to detect
such options in qemu-img

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
[mreitz: Dropped some iotests reference output hunks that became
         unnecessary thanks to
         "iotests: Make _filter_img_create more active"]
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200625125548.870061-12-mreitz@redhat.com>

1 files changed, 16 insertions, 2 deletions

diff --git a/qemu-img.c b/qemu-img.c
index 1a0a85089b..7f4938a5ef 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -4071,9 +4071,8 @@ static int print_amend_option_help(const char *format)
     /* Every driver supporting amendment must have amend_opts */
     assert(drv->amend_opts);
 
-    printf("Creation options for '%s':\n", format);
+    printf("Amend options for '%s':\n", format);
     qemu_opts_print_help(drv->amend_opts, false);
-    printf("\nNote that not all of these options may be amendable.\n");
     return 0;
 }
 
@@ -4219,7 +4218,22 @@ static int img_amend(int argc, char **argv)
     amend_opts = qemu_opts_append(amend_opts, bs->drv->amend_opts);
     opts = qemu_opts_create(amend_opts, NULL, 0, &error_abort);
     qemu_opts_do_parse(opts, options, NULL, &err);
+
     if (err) {
+        /* Try to parse options using the create options */
+        Error *err1 = NULL;
+        amend_opts = qemu_opts_append(amend_opts, bs->drv->create_opts);
+        qemu_opts_del(opts);
+        opts = qemu_opts_create(amend_opts, NULL, 0, &error_abort);
+        qemu_opts_do_parse(opts, options, NULL, &err1);
+
+        if (!err1) {
+            error_append_hint(&err,
+                              "This option is only supported for image creation\n");
+        } else {
+            error_free(err1);
+        }
+
         error_report_err(err);
         ret = -1;
         goto out;