fsnotify: ignored_mask - excluding notification

The ignored_mask is a new mask which is part of fsnotify marks.  A group's
should_send_event() function can use the ignored mask to determine that
certain events are not of interest.  In particular if a group registers a
mask including FS_OPEN on a vfsmount they could add FS_OPEN to the
ignored_mask for individual inodes and not send open events for those
inodes.

Signed-off-by: Eric Paris <eparis@redhat.com>

2 files changed, 9 insertions, 0 deletions

diff --git a/fs/notify/mark.c b/fs/notify/mark.c
index 0ebc3fd7089b..cb1d822f227f 100644
--- a/fs/notify/mark.c
+++ b/fs/notify/mark.c
@@ -190,6 +190,12 @@ void fsnotify_set_mark_mask_locked(struct fsnotify_mark *mark, __u32 mask)
                 fsnotify_set_inode_mark_mask_locked(mark, mask);
 }
 
+void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask)
+{
+        assert_spin_locked(&mark->lock);
+
+        mark->ignored_mask = mask;
+}
 
 /*
  * Attach an initialized mark to a given group and fs object.
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 489c881ed4ec..018416ec5ce4 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -266,6 +266,7 @@ struct fsnotify_mark {
                 struct fsnotify_inode_mark i;
                 struct fsnotify_vfsmount_mark m;
         };
+        __u32 ignored_mask;             /* events types to ignore */
         struct list_head free_g_list;   /* tmp list used when freeing this mark */
 #define FSNOTIFY_MARK_FLAG_INODE                0x01
 #define FSNOTIFY_MARK_FLAG_VFSMOUNT             0x02
@@ -373,6 +374,8 @@ extern struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *gro
 extern struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group, struct vfsmount *mnt);
 /* copy the values from old into new */
 extern void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old);
+/* set the ignored_mask of a mark */
+extern void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mask);
 /* set the mask of a mark (might pin the object into memory */
 extern void fsnotify_set_mark_mask_locked(struct fsnotify_mark *mark, __u32 mask);
 /* attach the mark to both the group and the inode */