fanotify: prepare for setting event flags in ignore mask

Setting flags FAN_ONDIR FAN_EVENT_ON_CHILD in ignore mask has no effect.
The FAN_EVENT_ON_CHILD flag in mask implicitly applies to ignore mask and
ignore mask is always implicitly applied to events on directories.

Define a mark flag that replaces this legacy behavior with logic of
applying the ignore mask according to event flags in ignore mask.

Implement the new logic to prepare for supporting an ignore mask that
ignores events on children and ignore mask that does not ignore events
on directories.

To emphasize the change in terminology, also rename ignored_mask mark
member to ignore_mask and use accessors to get only the effective
ignored events or the ignored events and flags.

This change in terminology finally aligns with the "ignore mask"
language in man pages and in most of the comments.

Link: https://lore.kernel.org/r/20220629144210.2983229-2-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 12 insertions, 9 deletions

diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 0b3e74935cb4..8687562df2e3 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -324,7 +324,8 @@ static int send_to_group(__u32 mask, const void *data, int data_type,
 	struct fsnotify_group *group = NULL;
 	__u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS);
 	__u32 marks_mask = 0;
-	__u32 marks_ignored_mask = 0;
+	__u32 marks_ignore_mask = 0;
+	bool is_dir = mask & FS_ISDIR;
 	struct fsnotify_mark *mark;
 	int type;
 
@@ -336,7 +337,7 @@ static int send_to_group(__u32 mask, const void *data, int data_type,
 		fsnotify_foreach_iter_mark_type(iter_info, mark, type) {
 			if (!(mark->flags &
 			      FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY))
-				mark->ignored_mask = 0;
+				mark->ignore_mask = 0;
 		}
 	}
 
@@ -344,14 +345,15 @@ static int send_to_group(__u32 mask, const void *data, int data_type,
 	fsnotify_foreach_iter_mark_type(iter_info, mark, type) {
 		group = mark->group;
 		marks_mask |= mark->mask;
-		marks_ignored_mask |= mark->ignored_mask;
+		marks_ignore_mask |=
+			fsnotify_effective_ignore_mask(mark, is_dir, type);
 	}
 
-	pr_debug("%s: group=%p mask=%x marks_mask=%x marks_ignored_mask=%x data=%p data_type=%d dir=%p cookie=%d\n",
-		 __func__, group, mask, marks_mask, marks_ignored_mask,
+	pr_debug("%s: group=%p mask=%x marks_mask=%x marks_ignore_mask=%x data=%p data_type=%d dir=%p cookie=%d\n",
+		 __func__, group, mask, marks_mask, marks_ignore_mask,
 		 data, data_type, dir, cookie);
 
-	if (!(test_mask & marks_mask & ~marks_ignored_mask))
+	if (!(test_mask & marks_mask & ~marks_ignore_mask))
 		return 0;
 
 	if (group->ops->handle_event) {
@@ -423,7 +425,8 @@ static bool fsnotify_iter_select_report_types(
 			 * But is *this mark* watching children?
 			 */
 			if (type == FSNOTIFY_ITER_TYPE_PARENT &&
-			    !(mark->mask & FS_EVENT_ON_CHILD))
+			    !(mark->mask & FS_EVENT_ON_CHILD) &&
+			    !(fsnotify_ignore_mask(mark) & FS_EVENT_ON_CHILD))
 				continue;
 
 			fsnotify_iter_set_report_type(iter_info, type);
@@ -532,8 +535,8 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,
 
 
 	/*
-	 * If this is a modify event we may need to clear some ignored masks.
-	 * In that case, the object with ignored masks will have the FS_MODIFY
+	 * If this is a modify event we may need to clear some ignore masks.
+	 * In that case, the object with ignore masks will have the FS_MODIFY
 	 * event in its mask.
 	 * Otherwise, return if none of the marks care about this type of event.
 	 */