storage: Always set config on cleartext block during mounting

UDisks2 allows any block object to be used to update configuration
items for any other block, and the mounting dialog was abusing that
when mounting an encrypted filesystem: It would use the backing block
to update the fstab entries of the cleartext block. This works
perfectly fine, except that UDisks2 only guarantees proper
notification ordering for the block used to make the method call.

Thus, when calling UpdateConfiguration on the backing block, the
"Configuration" property of the cleartext block would not necessarily
be up-to-date yet when mount_at accesses it.

pkg/storaged/filesystem/mounting-dialog.jsx

@@ -243,16 +243,18 @@ export function mounting_dialog(client, block, mode, forced_options, subvol) {
                 return Promise.resolve();
         }
 
-        function maybe_unlock() {
+        async function maybe_unlock() {
             const crypto = client.blocks_crypto[block.path];
             if (mode == "mount" && crypto) {
-                return (unlock_with_type(client, block, passphrase, passphrase_type)
-                        .catch(error => {
-                            dlg.set_values({ needs_explicit_passphrase: true });
-                            return Promise.reject(error);
-                        }));
+                try {
+                    await unlock_with_type(client, block, passphrase, passphrase_type);
+                    return await client.wait_for(() => client.blocks_cleartext[block.path]);
+                } catch (error) {
+                    dlg.set_values({ needs_explicit_passphrase: true });
+                    throw error;
+                }
             } else
-                return Promise.resolve();
+                return block;
         }
 
         function maybe_lock() {
@@ -275,14 +277,14 @@ export function mounting_dialog(client, block, mode, forced_options, subvol) {
         return (reload_systemd()
                 .then(() => teardown_active_usage(client, usage))
                 .then(maybe_unlock)
-                .then(() => {
+                .then(content_block => {
                     if (!old_config && new_config)
-                        return (block.AddConfigurationItem(new_config, {})
+                        return (content_block.AddConfigurationItem(new_config, {})
                                 .then(maybe_mount));
                     else if (old_config && !new_config)
-                        return block.RemoveConfigurationItem(old_config, {});
+                        return content_block.RemoveConfigurationItem(old_config, {});
                     else if (old_config && new_config)
-                        return (block.UpdateConfigurationItem(old_config, new_config, {})
+                        return (content_block.UpdateConfigurationItem(old_config, new_config, {})
                                 .then(maybe_mount));
                     else if (new_config && !is_mounted(client, block))
                         return maybe_mount();