block: Add options QDict to bdrv_open_common()

The options are passed down to the block drivers, which are supposed to
remove all options they have processed. Anything that is left over in
the end is an unknown option and results in an error.

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

block.c

@@ -665,15 +665,18 @@ static int bdrv_open_flags(BlockDriverState *bs, int flags)
 
 /*
  * Common part for opening disk images and files
+ *
+ * Removes all processed options from *options.
  */
 static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,
-    const char *filename,
+    const char *filename, QDict *options,
     int flags, BlockDriver *drv)
 {
     int ret, open_flags;
 
     assert(drv != NULL);
     assert(bs->file == NULL);
+    assert(options == NULL || bs->options != options);
 
     trace_bdrv_open_common(bs, filename, flags, drv->format_name);
 
@@ -710,7 +713,7 @@ static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,
     } else {
         assert(file != NULL);
         bs->file = file;
-        ret = drv->bdrv_open(bs, NULL, open_flags);
+        ret = drv->bdrv_open(bs, options, open_flags);
     }
 
     if (ret < 0) {
@@ -752,7 +755,7 @@ int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags)
     }
 
     bs = bdrv_new("");
-    ret = bdrv_open_common(bs, NULL, filename, flags, drv);
+    ret = bdrv_open_common(bs, NULL, filename, NULL, flags, drv);
     if (ret < 0) {
         bdrv_delete(bs);
         return ret;
@@ -821,6 +824,7 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
     }
 
     bs->options = options;
+    options = qdict_clone_shallow(options);
 
     /* For snapshot=on, create a temporary qcow2 overlay */
     if (flags & BDRV_O_SNAPSHOT) {
@@ -903,7 +907,7 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
     }
 
     /* Open the image */
-    ret = bdrv_open_common(bs, file, filename, flags, drv);
+    ret = bdrv_open_common(bs, file, filename, options, flags, drv);
     if (ret < 0) {
         goto unlink_and_fail;
     }
@@ -917,11 +921,22 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
     if ((flags & BDRV_O_NO_BACKING) == 0) {
         ret = bdrv_open_backing_file(bs);
         if (ret < 0) {
-            bdrv_close(bs);
-            return ret;
+            goto close_and_fail;
         }
     }
 
+    /* Check if any unknown options were used */
+    if (qdict_size(options) != 0) {
+        const QDictEntry *entry = qdict_first(options);
+        qerror_report(ERROR_CLASS_GENERIC_ERROR, "Block format '%s' used by "
+            "device '%s' doesn't support the option '%s'",
+            drv->format_name, bs->device_name, entry->key);
+
+        ret = -EINVAL;
+        goto close_and_fail;
+    }
+    QDECREF(options);
+
     if (!bdrv_key_required(bs)) {
         bdrv_dev_change_media_cb(bs, true);
     }
@@ -942,8 +957,13 @@ int bdrv_open(BlockDriverState *bs, const char *filename, QDict *options,
     }
 fail:
     QDECREF(bs->options);
+    QDECREF(options);
     bs->options = NULL;
+    return ret;
 
+close_and_fail:
+    bdrv_close(bs);
+    QDECREF(options);
     return ret;
 }