[gvfs] afc: Cleanup force-unmount idle on finalize

[Christophe Fergeau <teuf src gnome org>]

commit 63e3d144784eefe112de6b4e821664ebef94b0ab
Author: Christophe Fergeau <cfergeau redhat com>
Date:   Wed Jul 1 18:29:56 2015 +0200

    afc: Cleanup force-unmount idle on finalize
    
    When GvfsBackendAfc is finalized, if we have a pending idle for a force
    unmount, we need to remove it as by the time it runs, the GvfsBackendAfc
    it's acting on will no longer be valid.
    
    This fixes https://bugzilla.gnome.org/show_bug.cgi?id=751537 which can
    be reproduced by plugging an iDevice, unmounting it in Nautilus, and
    quickly unplugging it right after clicking on the eject icon.

 daemon/gvfsbackendafc.c |   32 ++++++++++++++++++++++++++++++--
 1 files changed, 30 insertions(+), 2 deletions(-)
---
diff --git a/daemon/gvfsbackendafc.c b/daemon/gvfsbackendafc.c
index 22bab16..1c041a8 100644
--- a/daemon/gvfsbackendafc.c
+++ b/daemon/gvfsbackendafc.c
@@ -87,6 +87,8 @@ struct _GVfsBackendAfc {
   idevice_t dev;
   afc_client_t afc_cli; /* for ACCESS_MODE_AFC */
 
+  guint force_umount_id;
+
   /* for ACCESS_MODE_HOUSE_ARREST */
   GHashTable *apps; /* hash table of AppInfo */
   instproxy_client_t inst;
@@ -353,6 +355,9 @@ force_umount_idle (gpointer user_data)
 
   g_vfs_backend_force_unmount (G_VFS_BACKEND(afc_backend));
 
+  afc_backend->force_umount_id = 0;
+  g_object_unref (afc_backend);
+
   return G_SOURCE_REMOVE;
 }
 
@@ -372,9 +377,20 @@ _idevice_event_cb (const idevice_event_t *event, void *user_data)
 
   g_print ("Shutting down AFC backend for device uuid %s\n", afc_backend->uuid);
 
-  /* idevice_event_unsubscribe() will terminate the thread _idevice_event_cb
+  /* This might happen if the user manages to unplug/replug/unplug the same device
+   * before the idle runs
+   */
+  if (afc_backend->force_umount_id != 0)
+    {
+      g_print ("AFC device with uuid %s is already being removed",
+               afc_backend->uuid);
+      return;
+    }
+
+  /* idevice_event_unsubscribe () will terminate the thread _idevice_event_cb
    * is running in, so we need to call back into our main loop */
-  g_idle_add(force_umount_idle, afc_backend);
+  afc_backend->force_umount_id = g_idle_add (force_umount_idle,
+                                             g_object_ref (afc_backend));
 }
 
 static gboolean
@@ -759,6 +775,8 @@ g_vfs_backend_afc_unmount (GVfsBackend *backend,
 {
   GVfsBackendAfc *self;
 
+  idevice_event_unsubscribe ();
+
   /* FIXME: check on G_MOUNT_UNMOUNT_FORCE flag */
   self = G_VFS_BACKEND_AFC (backend);
   g_vfs_backend_afc_close_connection (self);
@@ -2722,6 +2740,16 @@ g_vfs_backend_afc_finalize (GObject *obj)
   self = G_VFS_BACKEND_AFC(obj);
   g_vfs_backend_afc_close_connection (self);
 
+  idevice_event_unsubscribe ();
+  /* After running idevice_event_unsubscribe() we won't get any new event
+   * notifications, but we are also guaranteed that currently running event
+   * callbacks will have completed, so no other thread is going to requeue
+   * an idle after we removed it */
+  if (self->force_umount_id != 0) {
+      g_source_remove(self->force_umount_id);
+      self->force_umount_id = 0;
+  }
+
   if (G_OBJECT_CLASS(g_vfs_backend_afc_parent_class)->finalize)
     (*G_OBJECT_CLASS(g_vfs_backend_afc_parent_class)->finalize) (obj);
 }