Merge remote-tracking branch 'mdroth/qga-pull-4-27-12' into staging

* mdroth/qga-pull-4-27-12:
  qemu-ga: persist tracking of fsfreeze state via filesystem
  qemu-ga: add a whitelist for fsfreeze-safe commands
  qemu-ga: improve recovery options for fsfreeze

qapi-schema-guest.json

@@ -296,14 +296,10 @@
 #
 # @frozen: all non-network guest filesystems frozen
 #
-# @error: failure to thaw 1 or more
-#         previously frozen filesystems, or failure to open a previously
-#         cached filesytem (filesystem unmounted/directory changes, etc).
-#
 # Since: 0.15.0
 ##
 { 'enum': 'GuestFsfreezeStatus',
-  'data': [ 'thawed', 'frozen', 'error' ] }
+  'data': [ 'thawed', 'frozen' ] }
 
 ##
 # @guest-fsfreeze-status:
@@ -312,6 +308,9 @@
 #
 # Returns: GuestFsfreezeStatus ("thawed", "frozen", etc., as defined below)
 #
+# Note: This may fail to properly report the current state as a result of
+# some other guest processes having issued an fs freeze/thaw.
+#
 # Since: 0.15.0
 ##
 { 'command': 'guest-fsfreeze-status',
@@ -320,9 +319,10 @@
 ##
 # @guest-fsfreeze-freeze:
 #
-# Sync and freeze all non-network guest filesystems
+# Sync and freeze all freezable, local guest filesystems
 #
-# Returns: Number of file systems frozen on success
+# Returns: Number of file systems currently frozen. On error, all filesystems
+# will be thawed.
 #
 # Since: 0.15.0
 ##
@@ -332,10 +332,15 @@
 ##
 # @guest-fsfreeze-thaw:
 #
-# Unfreeze frozen guest fileystems
+# Unfreeze all frozen guest filesystems
+#
+# Returns: Number of file systems thawed by this call
 #
-# Returns: Number of file systems thawed
-#          If error, -1 (unknown error) or -errno
+# Note: if return value does not match the previous call to
+#       guest-fsfreeze-freeze, this likely means some freezable
+#       filesystems were unfrozen before this call, and that the
+#       filesystem state may have changed before issuing this
+#       command.
 #
 # Since: 0.15.0
 ##

qapi/qmp-core.h

@@ -38,6 +38,7 @@ void qmp_register_command(const char *name, QmpCommandFunc *fn);
 QmpCommand *qmp_find_command(const char *name);
 QObject *qmp_dispatch(QObject *request);
 void qmp_disable_command(const char *name);
+void qmp_enable_command(const char *name);
 bool qmp_command_is_enabled(const char *name);
 char **qmp_get_command_list(void);
 

qapi/qmp-registry.c

@@ -40,18 +40,28 @@ QmpCommand *qmp_find_command(const char *name)
     return NULL;
 }
 
-void qmp_disable_command(const char *name)
+static void qmp_toggle_command(const char *name, bool enabled)
 {
     QmpCommand *cmd;
 
     QTAILQ_FOREACH(cmd, &qmp_commands, node) {
         if (strcmp(cmd->name, name) == 0) {
-            cmd->enabled = false;
+            cmd->enabled = enabled;
             return;
         }
     }
 }
 
+void qmp_disable_command(const char *name)
+{
+    qmp_toggle_command(name, false);
+}
+
+void qmp_enable_command(const char *name)
+{
+    qmp_toggle_command(name, true);
+}
+
 bool qmp_command_is_enabled(const char *name)
 {
     QmpCommand *cmd;