fsnotify: add marks to inodes so groups can interpret how to handle those inodes

This patch creates a way for fsnotify groups to attach marks to inodes.
These marks have little meaning to the generic fsnotify infrastructure
and thus their meaning should be interpreted by the group that attached
them to the inode's list.

dnotify and inotify  will make use of these markings to indicate which
inodes are of interest to their respective groups.  But this implementation
has the useful property that in the future other listeners could actually
use the marks for the exact opposite reason, aka to indicate which inodes
it had NO interest in.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 83d6b4397245..275b0860044c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -755,6 +755,11 @@ struct inode {
 
         __u32                   i_generation;
 
+#ifdef CONFIG_FSNOTIFY
+        __u32                   i_fsnotify_mask; /* all events this inode cares about */
+        struct hlist_head       i_fsnotify_mark_entries; /* fsnotify mark entries */
+#endif
+
 #ifdef CONFIG_DNOTIFY
         unsigned long           i_dnotify_mask; /* Directory notify events */
         struct dnotify_struct   *i_dnotify; /* for directory notifications */