[PATCH v3 3/8] fanotify: simplify handling of FAN_ONDIR

[Amir Goldstein <amir73il@xxxxxxxxx>]

fanotify mark add/remove code jumps through hoops to avoid setting the
FS_ISDIR in the commulative object mask.

That was just papering over a bug in fsnotify() handling of the FS_ISDIR
extra flag. This bug is now fixed, so all the hoops can be removed along
with the unneeded internal flag FAN_MARK_ONDIR.

Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
 fs/notify/fanotify/fanotify_user.c | 32 +++++-------------------------
 include/linux/fanotify.h           |  3 ---
 2 files changed, 5 insertions(+), 30 deletions(-)

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 15719d4aa4b5..34b511407035 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -506,18 +506,10 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
 
 	spin_lock(&fsn_mark->lock);
 	if (!(flags & FAN_MARK_IGNORED_MASK)) {
-		__u32 tmask = fsn_mark->mask & ~mask;
-
-		if (flags & FAN_MARK_ONDIR)
-			tmask &= ~FAN_ONDIR;
-
 		oldmask = fsn_mark->mask;
-		fsn_mark->mask = tmask;
+		fsn_mark->mask &= ~mask;
 	} else {
-		__u32 tmask = fsn_mark->ignored_mask & ~mask;
-		if (flags & FAN_MARK_ONDIR)
-			tmask &= ~FAN_ONDIR;
-		fsn_mark->ignored_mask = tmask;
+		fsn_mark->ignored_mask &= ~mask;
 	}
 	*destroy = !(fsn_mark->mask | fsn_mark->ignored_mask);
 	spin_unlock(&fsn_mark->lock);
@@ -586,19 +578,10 @@ static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
 
 	spin_lock(&fsn_mark->lock);
 	if (!(flags & FAN_MARK_IGNORED_MASK)) {
-		__u32 tmask = fsn_mark->mask | mask;
-
-		if (flags & FAN_MARK_ONDIR)
-			tmask |= FAN_ONDIR;
-
 		oldmask = fsn_mark->mask;
-		fsn_mark->mask = tmask;
+		fsn_mark->mask |= mask;
 	} else {
-		__u32 tmask = fsn_mark->ignored_mask | mask;
-		if (flags & FAN_MARK_ONDIR)
-			tmask |= FAN_ONDIR;
-
-		fsn_mark->ignored_mask = tmask;
+		fsn_mark->ignored_mask |= mask;
 		if (flags & FAN_MARK_IGNORED_SURV_MODIFY)
 			fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
 	}
@@ -820,7 +803,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	struct fsnotify_group *group;
 	struct fd f;
 	struct path path;
-	u32 valid_mask = FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD;
+	u32 valid_mask = FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD | FAN_ONDIR;
 	unsigned int mark_type = flags & FAN_MARK_TYPE_MASK;
 	int ret;
 
@@ -857,11 +840,6 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 		return -EINVAL;
 	}
 
-	if (mask & FAN_ONDIR) {
-		flags |= FAN_MARK_ONDIR;
-		mask &= ~FAN_ONDIR;
-	}
-
 	if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS))
 		valid_mask |= FAN_ALL_PERM_EVENTS;
 
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index e70fccc3757e..a8c3fc54276d 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -4,9 +4,6 @@
 
 #include <uapi/linux/fanotify.h>
 
-/* not valid from userspace, only kernel internal */
-#define FAN_MARK_ONDIR		0x80000000
-
 #define FAN_GROUP_FLAG(group, flag) \
 	((group)->fanotify_data.flags & (flag))
 
-- 
2.17.1