1 files changed, 70 insertions, 22 deletions

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 23b5cfbeed50..a61aaa710825 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -21,6 +21,7 @@
 #include <linux/gfp.h>
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/mount.h>
 #include <linux/srcu.h>
 
 #include <linux/fsnotify_backend.h>
@@ -134,6 +135,45 @@ void __fsnotify_parent(struct file *file, struct dentry *dentry, __u32 mask)
 }
 EXPORT_SYMBOL_GPL(__fsnotify_parent);
 
+static void send_to_group(__u32 mask,
+			  struct fsnotify_group *group,
+			  void *data, int data_is, const char *file_name,
+			  u32 cookie, struct fsnotify_event **event,
+			  struct inode *to_tell)
+{
+	if (!group->ops->should_send_event(group, to_tell, mask,
+					   data, data_is))
+		return;
+	if (!*event) {
+		*event = fsnotify_create_event(to_tell, mask, data,
+						data_is, file_name,
+						cookie, GFP_KERNEL);
+		/*
+		 * shit, we OOM'd and now we can't tell, maybe
+		 * someday someone else will want to do something
+		 * here
+		 */
+		if (!*event)
+			return;
+	}
+	group->ops->handle_event(group, *event);
+}
+
+static bool needed_by_vfsmount(__u32 test_mask, void *data, int data_is)
+{
+	struct path *path;
+
+	if (data_is == FSNOTIFY_EVENT_PATH)
+		path = (struct path *)data;
+	else if (data_is == FSNOTIFY_EVENT_FILE)
+		path = &((struct file *)data)->f_path;
+	else
+		return false;
+
+	/* hook in this when mnt->mnt_fsnotify_mask is defined */
+	/* return (test_mask & path->mnt->mnt_fsnotify_mask); */
+	return false;
+}
 /*
  * This is the main call to fsnotify.  The VFS calls into hook specific functions
  * in linux/fsnotify.h.  Those functions then in turn call here.  Here will call
@@ -148,38 +188,46 @@ void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const
 	/* global tests shouldn't care about events on child only the specific event */
 	__u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
 
-	if (list_empty(&fsnotify_inode_groups))
-		return;
+	/* if no fsnotify listeners, nothing to do */
+	if (list_empty(&fsnotify_inode_groups) &&
+	    list_empty(&fsnotify_vfsmount_groups))
+                return;
+ 
+	/* if none of the directed listeners or vfsmount listeners care */
+	if (!(test_mask & fsnotify_inode_mask) &&
+	    !(test_mask & fsnotify_vfsmount_mask))
+                return;
+ 
+	/* if this inode's directed listeners don't care and nothing on the vfsmount
+	 * listeners list cares, nothing to do */
+	if (!(test_mask & to_tell->i_fsnotify_mask) &&
+	    !needed_by_vfsmount(test_mask, data, data_is))
+                return;
 
-	if (!(test_mask & fsnotify_inode_mask))
-		return;
-
-	if (!(test_mask & to_tell->i_fsnotify_mask))
-		return;
 	/*
 	 * SRCU!!  the groups list is very very much read only and the path is
 	 * very hot.  The VAST majority of events are not going to need to do
 	 * anything other than walk the list so it's crazy to pre-allocate.
 	 */
 	idx = srcu_read_lock(&fsnotify_grp_srcu);
-	list_for_each_entry_rcu(group, &fsnotify_inode_groups, inode_group_list) {
-		if (test_mask & group->mask) {
-			if (!group->ops->should_send_event(group, to_tell, mask,
-							   data, data_is))
-				continue;
-			if (!event) {
-				event = fsnotify_create_event(to_tell, mask, data,
-							      data_is, file_name, cookie,
-							      GFP_KERNEL);
-				/* shit, we OOM'd and now we can't tell, maybe
-				 * someday someone else will want to do something
-				 * here */
-				if (!event)
-					break;
+
+	if (test_mask & to_tell->i_fsnotify_mask) {
+		list_for_each_entry_rcu(group, &fsnotify_inode_groups, inode_group_list) {
+			if (test_mask & group->mask) {
+				send_to_group(mask, group, data, data_is,
+					      file_name, cookie, &event, to_tell);
 			}
-			group->ops->handle_event(group, event);
 		}
 	}
+	if (needed_by_vfsmount(test_mask, data, data_is)) {
+		list_for_each_entry_rcu(group, &fsnotify_vfsmount_groups, vfsmount_group_list) {
+			if (test_mask & group->mask) {
+				send_to_group(mask, group, data, data_is,
+					      file_name, cookie, &event, to_tell);
+			}
+		}
+	}
+
 	srcu_read_unlock(&fsnotify_grp_srcu, idx);
 	/*
 	 * fsnotify_create_event() took a reference so the event can't be cleaned