inotify: reimplement inotify using fsnotify

Reimplement inotify_user using fsnotify.  This should be feature for feature
exactly the same as the original inotify_user.  This does not make any changes
to the in kernel inotify feature used by audit.  Those patches (and the eventual
removal of in kernel inotify) will come after the new inotify_user proves to be
working correctly.

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, 11 insertions, 0 deletions

diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index d2c0ee30e618..44848aa830dc 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -9,6 +9,7 @@
 
 #ifdef __KERNEL__
 
+#include <linux/idr.h> /* inotify uses this */
 #include <linux/fs.h> /* struct inode */
 #include <linux/list.h>
 #include <linux/path.h> /* struct path */
@@ -59,6 +60,7 @@
 
 /* listeners that hard code group numbers near the top */
 #define DNOTIFY_GROUP_NUM	UINT_MAX
+#define INOTIFY_GROUP_NUM	(DNOTIFY_GROUP_NUM-1)
 
 struct fsnotify_group;
 struct fsnotify_event;
@@ -141,6 +143,15 @@ struct fsnotify_group {
 	/* groups can define private fields here or use the void *private */
 	union {
 		void *private;
+#ifdef CONFIG_INOTIFY_USER
+		struct inotify_group_private_data {
+			spinlock_t	idr_lock;
+			struct idr      idr;
+			u32             last_wd;
+			struct fasync_struct    *fa;    /* async notification */
+			struct user_struct      *user;
+		} inotify_data;
+#endif
 	};
 };