[RFC,1/2] fsnotify: add event mask FS_EVENT_ON_SB

Commit Message

Amir Goldstein Dec. 20, 2016, 3:20 p.m. UTC

When a watch is added on a super block's root inode with
the FS_EVENT_ON_SB flag, the watched inode is intended
to report events on all inodes on the same super block.

Signed-off-by: Amir Goldstein <[e-mail]>
---
 fs/notify/fsnotify.c             |  2 +-
 include/linux/fsnotify_backend.h | 19 ++++++++++++++++---
 2 files changed, 17 insertions(+), 4 deletions(-)

Patch

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 3ba0e4a..12d4479 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -297,7 +297,7 @@  static __init int fsnotify_init(void)
 {
 	int ret;
 
-	BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 23);
+	BUG_ON(hweight32(ALL_FSNOTIFY_EVENTS) != 24);
 
 	ret = init_srcu_struct(&fsnotify_mark_srcu);
 	if (ret)
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index b55c64d..b7992da 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -54,6 +54,13 @@ 
  * dnotify and inotify. */
 #define FS_EVENT_ON_CHILD	0x08000000
 
+/* This root inode cares about things that happen to inodes on same super block.
+ * Can only be set for fanotify.
+ * Overloads IN_ONLYDIR inotify open only flag */
+#define FS_EVENT_ON_SB		0x01000000
+
+#define FS_EVENT_ON_DESCENDANT	(FS_EVENT_ON_CHILD | FS_EVENT_ON_SB)
+
 /* This is a list of all events that may get sent to a parernt based on fs event
  * happening to inodes inside that directory */
 #define FS_EVENTS_POSS_ON_CHILD   (FS_ACCESS | FS_MODIFY | FS_ATTRIB |\
@@ -61,6 +68,11 @@ 
 				   FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE |\
 				   FS_DELETE | FS_OPEN_PERM | FS_ACCESS_PERM)
 
+/* This is a list of all events that may get sent to the root inode based on fs
+ * event happening to inodes on the same super block */
+#define FS_EVENTS_POSS_ON_SB   (FS_EVENTS_POSS_ON_CHILD |\
+				FS_DELETE_SELF | FS_MOVE_SELF)
+
 #define FS_MOVE			(FS_MOVED_FROM | FS_MOVED_TO)
 
 #define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM)
@@ -70,9 +82,10 @@ 
 			     FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE | \
 			     FS_DELETE | FS_DELETE_SELF | FS_MOVE_SELF | \
 			     FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
-			     FS_OPEN_PERM | FS_ACCESS_PERM | FS_EXCL_UNLINK | \
-			     FS_ISDIR | FS_IN_ONESHOT | FS_DN_RENAME | \
-			     FS_DN_MULTISHOT | FS_EVENT_ON_CHILD)
+			     FS_OPEN_PERM | FS_ACCESS_PERM | \
+			     FS_EXCL_UNLINK | FS_ISDIR | FS_IN_ONESHOT | \
+			     FS_DN_RENAME | FS_DN_MULTISHOT | \
+			     FS_EVENT_ON_CHILD | FS_EVENT_ON_SB)
 
 struct fsnotify_group;
 struct fsnotify_event;