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-rw-r--r--fs/notify/fanotify/fanotify.c13
-rw-r--r--fs/notify/fanotify/fanotify_user.c36
-rw-r--r--fs/notify/group.c19
-rw-r--r--fs/notify/notification.c23
4 files changed, 51 insertions, 40 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index d2f97ecca..e0e5f7c3c 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -67,18 +67,7 @@ static int fanotify_get_response(struct fsnotify_group *group,
pr_debug("%s: group=%p event=%p\n", __func__, group, event);
- wait_event(group->fanotify_data.access_waitq, event->response ||
- atomic_read(&group->fanotify_data.bypass_perm));
-
- if (!event->response) { /* bypass_perm set */
- /*
- * Event was canceled because group is being destroyed. Remove
- * it from group's event list because we are responsible for
- * freeing the permission event.
- */
- fsnotify_remove_event(group, &event->fae.fse);
- return 0;
- }
+ wait_event(group->fanotify_data.access_waitq, event->response);
/* userspace responded, convert to something usable */
switch (event->response) {
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 8e8e6bcd1..a64313868 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -358,16 +358,20 @@ static int fanotify_release(struct inode *ignored, struct file *file)
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
struct fanotify_perm_event_info *event, *next;
+ struct fsnotify_event *fsn_event;
/*
- * There may be still new events arriving in the notification queue
- * but since userspace cannot use fanotify fd anymore, no event can
- * enter or leave access_list by now.
+ * Stop new events from arriving in the notification queue. since
+ * userspace cannot use fanotify fd anymore, no event can enter or
+ * leave access_list by now either.
*/
- spin_lock(&group->fanotify_data.access_lock);
-
- atomic_inc(&group->fanotify_data.bypass_perm);
+ fsnotify_group_stop_queueing(group);
+ /*
+ * Process all permission events on access_list and notification queue
+ * and simulate reply from userspace.
+ */
+ spin_lock(&group->fanotify_data.access_lock);
list_for_each_entry_safe(event, next, &group->fanotify_data.access_list,
fae.fse.list) {
pr_debug("%s: found group=%p event=%p\n", __func__, group,
@@ -379,12 +383,21 @@ static int fanotify_release(struct inode *ignored, struct file *file)
spin_unlock(&group->fanotify_data.access_lock);
/*
- * Since bypass_perm is set, newly queued events will not wait for
- * access response. Wake up the already sleeping ones now.
- * synchronize_srcu() in fsnotify_destroy_group() will wait for all
- * processes sleeping in fanotify_handle_event() waiting for access
- * response and thus also for all permission events to be freed.
+ * Destroy all non-permission events. For permission events just
+ * dequeue them and set the response. They will be freed once the
+ * response is consumed and fanotify_get_response() returns.
*/
+ mutex_lock(&group->notification_mutex);
+ while (!fsnotify_notify_queue_is_empty(group)) {
+ fsn_event = fsnotify_remove_first_event(group);
+ if (!(fsn_event->mask & FAN_ALL_PERM_EVENTS))
+ fsnotify_destroy_event(group, fsn_event);
+ else
+ FANOTIFY_PE(fsn_event)->response = FAN_ALLOW;
+ }
+ mutex_unlock(&group->notification_mutex);
+
+ /* Response for all permission events it set, wakeup waiters */
wake_up(&group->fanotify_data.access_waitq);
#endif
@@ -755,7 +768,6 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
spin_lock_init(&group->fanotify_data.access_lock);
init_waitqueue_head(&group->fanotify_data.access_waitq);
INIT_LIST_HEAD(&group->fanotify_data.access_list);
- atomic_set(&group->fanotify_data.bypass_perm, 0);
#endif
switch (flags & FAN_ALL_CLASS_BITS) {
case FAN_CLASS_NOTIF:
diff --git a/fs/notify/group.c b/fs/notify/group.c
index b17cb4bd8..618bc9e5c 100644
--- a/fs/notify/group.c
+++ b/fs/notify/group.c
@@ -41,6 +41,17 @@ static void fsnotify_final_destroy_group(struct fsnotify_group *group)
}
/*
+ * Stop queueing new events for this group. Once this function returns
+ * fsnotify_add_event() will not add any new events to the group's queue.
+ */
+void fsnotify_group_stop_queueing(struct fsnotify_group *group)
+{
+ mutex_lock(&group->notification_mutex);
+ group->shutdown = true;
+ mutex_unlock(&group->notification_mutex);
+}
+
+/*
* Trying to get rid of a group. Remove all marks, flush all events and release
* the group reference.
* Note that another thread calling fsnotify_clear_marks_by_group() may still
@@ -48,6 +59,14 @@ static void fsnotify_final_destroy_group(struct fsnotify_group *group)
*/
void fsnotify_destroy_group(struct fsnotify_group *group)
{
+ /*
+ * Stop queueing new events. The code below is careful enough to not
+ * require this but fanotify needs to stop queuing events even before
+ * fsnotify_destroy_group() is called and this makes the other callers
+ * of fsnotify_destroy_group() to see the same behavior.
+ */
+ fsnotify_group_stop_queueing(group);
+
/* clear all inode marks for this group, attach them to destroy_list */
fsnotify_detach_group_marks(group);
diff --git a/fs/notify/notification.c b/fs/notify/notification.c
index a95d8e037..e455e83ce 100644
--- a/fs/notify/notification.c
+++ b/fs/notify/notification.c
@@ -82,7 +82,8 @@ void fsnotify_destroy_event(struct fsnotify_group *group,
* Add an event to the group notification queue. The group can later pull this
* event off the queue to deal with. The function returns 0 if the event was
* added to the queue, 1 if the event was merged with some other queued event,
- * 2 if the queue of events has overflown.
+ * 2 if the event was not queued - either the queue of events has overflown
+ * or the group is shutting down.
*/
int fsnotify_add_event(struct fsnotify_group *group,
struct fsnotify_event *event,
@@ -96,6 +97,11 @@ int fsnotify_add_event(struct fsnotify_group *group,
mutex_lock(&group->notification_mutex);
+ if (group->shutdown) {
+ mutex_unlock(&group->notification_mutex);
+ return 2;
+ }
+
if (group->q_len >= group->max_events) {
ret = 2;
/* Queue overflow event only if it isn't already queued */
@@ -126,21 +132,6 @@ queue:
}
/*
- * Remove @event from group's notification queue. It is the responsibility of
- * the caller to destroy the event.
- */
-void fsnotify_remove_event(struct fsnotify_group *group,
- struct fsnotify_event *event)
-{
- mutex_lock(&group->notification_mutex);
- if (!list_empty(&event->list)) {
- list_del_init(&event->list);
- group->q_len--;
- }
- mutex_unlock(&group->notification_mutex);
-}
-
-/*
* Remove and return the first event from the notification list. It is the
* responsibility of the caller to destroy the obtained event
*/