1 files changed, 32 insertions, 146 deletions

diff --git a/fs/notify/group.c b/fs/notify/group.c
index 9e9eb406afd..ad199598045 100644
--- a/fs/notify/group.c
+++ b/fs/notify/group.c
@@ -26,97 +26,13 @@
 #include <linux/fsnotify_backend.h>
 #include "fsnotify.h"
 
-#include <asm/atomic.h>
-
-/* protects writes to fsnotify_groups and fsnotify_mask */
-static DEFINE_MUTEX(fsnotify_grp_mutex);
-/* protects reads while running the fsnotify_groups list */
-struct srcu_struct fsnotify_grp_srcu;
-/* all groups registered to receive inode filesystem notifications */
-LIST_HEAD(fsnotify_inode_groups);
-/* all groups registered to receive mount point filesystem notifications */
-LIST_HEAD(fsnotify_vfsmount_groups);
-/* bitwise OR of all events (FS_*) interesting to some group on this system */
-__u32 fsnotify_inode_mask;
-/* bitwise OR of all events (FS_*) interesting to some group on this system */
-__u32 fsnotify_vfsmount_mask;
-
-/*
- * When a new group registers or changes it's set of interesting events
- * this function updates the fsnotify_mask to contain all interesting events
- */
-void fsnotify_recalc_global_mask(void)
-{
-	struct fsnotify_group *group;
-	__u32 inode_mask = 0;
-	__u32 vfsmount_mask = 0;
-	int idx;
-
-	idx = srcu_read_lock(&fsnotify_grp_srcu);
-	list_for_each_entry_rcu(group, &fsnotify_inode_groups, inode_group_list)
-		inode_mask |= group->mask;
-	list_for_each_entry_rcu(group, &fsnotify_vfsmount_groups, vfsmount_group_list)
-		vfsmount_mask |= group->mask;
-		
-	srcu_read_unlock(&fsnotify_grp_srcu, idx);
-
-	fsnotify_inode_mask = inode_mask;
-	fsnotify_vfsmount_mask = vfsmount_mask;
-}
-
-/*
- * Update the group->mask by running all of the marks associated with this
- * group and finding the bitwise | of all of the mark->mask.  If we change
- * the group->mask we need to update the global mask of events interesting
- * to the system.
- */
-void fsnotify_recalc_group_mask(struct fsnotify_group *group)
-{
-	__u32 mask = 0;
-	__u32 old_mask = group->mask;
-	struct fsnotify_mark *mark;
-
-	spin_lock(&group->mark_lock);
-	list_for_each_entry(mark, &group->marks_list, g_list)
-		mask |= mark->mask;
-	spin_unlock(&group->mark_lock);
-
-	group->mask = mask;
-
-	if (old_mask != mask)
-		fsnotify_recalc_global_mask();
-}
-
-void fsnotify_add_vfsmount_group(struct fsnotify_group *group)
-{
-	mutex_lock(&fsnotify_grp_mutex);
-
-	if (!group->on_vfsmount_group_list)
-		list_add_tail_rcu(&group->vfsmount_group_list, &fsnotify_vfsmount_groups);
-	group->on_vfsmount_group_list = 1;
-
-	mutex_unlock(&fsnotify_grp_mutex);
-}
-
-void fsnotify_add_inode_group(struct fsnotify_group *group)
-{
-	mutex_lock(&fsnotify_grp_mutex);
-
-	if (!group->on_inode_group_list)
-		list_add_tail_rcu(&group->inode_group_list, &fsnotify_inode_groups);
-	group->on_inode_group_list = 1;
-
-	mutex_unlock(&fsnotify_grp_mutex);
-}
+#include <linux/atomic.h>
 
 /*
  * Final freeing of a group
  */
 void fsnotify_final_destroy_group(struct fsnotify_group *group)
 {
-	/* clear the notification queue of all events */
-	fsnotify_flush_notify(group);
-
 	if (group->ops->free_group_priv)
 		group->ops->free_group_priv(group);
 
@@ -124,50 +40,37 @@ void fsnotify_final_destroy_group(struct fsnotify_group *group)
 }
 
 /*
- * Trying to get rid of a group.  We need to first get rid of any outstanding
- * allocations and then free the group.  Remember that fsnotify_clear_marks_by_group
- * could miss marks that are being freed by inode and those marks could still
- * hold a reference to this group (via group->num_marks)  If we get into that
- * situtation, the fsnotify_final_destroy_group will get called when that final
- * mark is freed.
+ * 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
+ * hold a ref to the group.
  */
-static void fsnotify_destroy_group(struct fsnotify_group *group)
+void fsnotify_destroy_group(struct fsnotify_group *group)
 {
 	/* clear all inode marks for this group */
 	fsnotify_clear_marks_by_group(group);
 
-	/* past the point of no return, matches the initial value of 1 */
-	if (atomic_dec_and_test(&group->num_marks))
-		fsnotify_final_destroy_group(group);
-}
+	synchronize_srcu(&fsnotify_mark_srcu);
 
-/*
- * Remove this group from the global list of groups that will get events
- * this can be done even if there are still references and things still using
- * this group.  This just stops the group from getting new events.
- */
-static void __fsnotify_evict_group(struct fsnotify_group *group)
-{
-	BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex));
-
-	if (group->on_inode_group_list)
-		list_del_rcu(&group->inode_group_list);
-	group->on_inode_group_list = 0;
-	if (group->on_vfsmount_group_list)
-		list_del_rcu(&group->vfsmount_group_list);
-	group->on_vfsmount_group_list = 0;
+	/* clear the notification queue of all events */
+	fsnotify_flush_notify(group);
+
+	/*
+	 * Destroy overflow event (we cannot use fsnotify_destroy_event() as
+	 * that deliberately ignores overflow events.
+	 */
+	if (group->overflow_event)
+		group->ops->free_event(group->overflow_event);
+
+	fsnotify_put_group(group);
 }
 
 /*
- * Called when a group is no longer interested in getting events.  This can be
- * used if a group is misbehaving or if for some reason a group should no longer
- * get any filesystem events.
+ * Get reference to a group.
  */
-void fsnotify_evict_group(struct fsnotify_group *group)
+void fsnotify_get_group(struct fsnotify_group *group)
 {
-	mutex_lock(&fsnotify_grp_mutex);
-	__fsnotify_evict_group(group);
-	mutex_unlock(&fsnotify_grp_mutex);
+	atomic_inc(&group->refcnt);
 }
 
 /*
@@ -175,25 +78,8 @@ void fsnotify_evict_group(struct fsnotify_group *group)
  */
 void fsnotify_put_group(struct fsnotify_group *group)
 {
-	if (!atomic_dec_and_mutex_lock(&group->refcnt, &fsnotify_grp_mutex))
-		return;
-
-	/*
-	 * OK, now we know that there's no other users *and* we hold mutex,
-	 * so no new references will appear
-	 */
-	__fsnotify_evict_group(group);
-
-	/*
-	 * now it's off the list, so the only thing we might care about is
-	 * srcu access....
-	 */
-	mutex_unlock(&fsnotify_grp_mutex);
-	synchronize_srcu(&fsnotify_grp_srcu);
-
-	/* and now it is really dead. _Nothing_ could be seeing it */
-	fsnotify_recalc_global_mask();
-	fsnotify_destroy_group(group);
+	if (atomic_dec_and_test(&group->refcnt))
+		fsnotify_final_destroy_group(group);
 }
 
 /*
@@ -209,24 +95,24 @@ struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops)
 
 	/* set to 0 when there a no external references to this group */
 	atomic_set(&group->refcnt, 1);
-	/*
-	 * hits 0 when there are no external references AND no marks for
-	 * this group
-	 */
-	atomic_set(&group->num_marks, 1);
+	atomic_set(&group->num_marks, 0);
 
 	mutex_init(&group->notification_mutex);
 	INIT_LIST_HEAD(&group->notification_list);
 	init_waitqueue_head(&group->notification_waitq);
 	group->max_events = UINT_MAX;
 
-	INIT_LIST_HEAD(&group->inode_group_list);
-	INIT_LIST_HEAD(&group->vfsmount_group_list);
-
-	spin_lock_init(&group->mark_lock);
+	mutex_init(&group->mark_mutex);
 	INIT_LIST_HEAD(&group->marks_list);
 
 	group->ops = ops;
 
 	return group;
 }
+
+int fsnotify_fasync(int fd, struct file *file, int on)
+{
+	struct fsnotify_group *group = file->private_data;
+
+	return fasync_helper(fd, file, on, &group->fsn_fa) >= 0 ? 0 : -EIO;
+}