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>

2 files changed, 23 insertions, 17 deletions

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 4f897e109547..cd7d09a569ff 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -295,12 +295,13 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
 				     const void *data, int data_type,
 				     struct inode *dir)
 {
-	__u32 marks_mask = 0, marks_ignored_mask = 0;
+	__u32 marks_mask = 0, marks_ignore_mask = 0;
 	__u32 test_mask, user_mask = FANOTIFY_OUTGOING_EVENTS |
 				     FANOTIFY_EVENT_FLAGS;
 	const struct path *path = fsnotify_data_path(data, data_type);
 	unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
 	struct fsnotify_mark *mark;
+	bool ondir = event_mask & FAN_ONDIR;
 	int type;
 
 	pr_debug("%s: report_mask=%x mask=%x data=%p data_type=%d\n",
@@ -315,19 +316,21 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
 			return 0;
 	} else if (!(fid_mode & FAN_REPORT_FID)) {
 		/* Do we have a directory inode to report? */
-		if (!dir && !(event_mask & FS_ISDIR))
+		if (!dir && !ondir)
 			return 0;
 	}
 
 	fsnotify_foreach_iter_mark_type(iter_info, mark, type) {
-		/* Apply ignore mask regardless of mark's ISDIR flag */
-		marks_ignored_mask |= mark->ignored_mask;
+		/*
+		 * Apply ignore mask depending on event flags in ignore mask.
+		 */
+		marks_ignore_mask |=
+			fsnotify_effective_ignore_mask(mark, ondir, type);
 
 		/*
-		 * If the event is on dir and this mark doesn't care about
-		 * events on dir, don't send it!
+		 * Send the event depending on event flags in mark mask.
 		 */
-		if (event_mask & FS_ISDIR && !(mark->mask & FS_ISDIR))
+		if (!fsnotify_mask_applicable(mark->mask, ondir, type))
 			continue;
 
 		marks_mask |= mark->mask;
@@ -336,7 +339,7 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
 		*match_mask |= 1U << type;
 	}
 
-	test_mask = event_mask & marks_mask & ~marks_ignored_mask;
+	test_mask = event_mask & marks_mask & ~marks_ignore_mask;
 
 	/*
 	 * For dirent modification events (create/delete/move) that do not carry
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index b08ce0d821a7..a9eea037fee9 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1012,7 +1012,7 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
 	if (!(flags & FAN_MARK_IGNORED_MASK)) {
 		fsn_mark->mask &= ~mask;
 	} else {
-		fsn_mark->ignored_mask &= ~mask;
+		fsn_mark->ignore_mask &= ~mask;
 	}
 	newmask = fsnotify_calc_mask(fsn_mark);
 	/*
@@ -1021,7 +1021,7 @@ static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
 	 * changes to the mask.
 	 * Destroy mark when only umask bits remain.
 	 */
-	*destroy = !((fsn_mark->mask | fsn_mark->ignored_mask) & ~umask);
+	*destroy = !((fsn_mark->mask | fsn_mark->ignore_mask) & ~umask);
 	spin_unlock(&fsn_mark->lock);
 
 	return oldmask & ~newmask;
@@ -1090,7 +1090,7 @@ static bool fanotify_mark_update_flags(struct fsnotify_mark *fsn_mark,
 	/*
 	 * Setting FAN_MARK_IGNORED_SURV_MODIFY for the first time may lead to
 	 * the removal of the FS_MODIFY bit in calculated mask if it was set
-	 * because of an ignored mask that is now going to survive FS_MODIFY.
+	 * because of an ignore mask that is now going to survive FS_MODIFY.
 	 */
 	if ((fan_flags & FAN_MARK_IGNORED_MASK) &&
 	    (fan_flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
@@ -1123,7 +1123,7 @@ static bool fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
 	if (!(fan_flags & FAN_MARK_IGNORED_MASK))
 		fsn_mark->mask |= mask;
 	else
-		fsn_mark->ignored_mask |= mask;
+		fsn_mark->ignore_mask |= mask;
 
 	recalc = fsnotify_calc_mask(fsn_mark) &
 		~fsnotify_conn_mask(fsn_mark->connector);
@@ -1261,7 +1261,7 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group,
 
 	/*
 	 * If some other task has this inode open for write we should not add
-	 * an ignored mark, unless that ignored mark is supposed to survive
+	 * an ignore mask, unless that ignore mask is supposed to survive
 	 * modification changes anyway.
 	 */
 	if ((flags & FAN_MARK_IGNORED_MASK) &&
@@ -1557,7 +1557,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	__kernel_fsid_t __fsid, *fsid = NULL;
 	u32 valid_mask = FANOTIFY_EVENTS | FANOTIFY_EVENT_FLAGS;
 	unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
-	bool ignored = flags & FAN_MARK_IGNORED_MASK;
+	bool ignore = flags & FAN_MARK_IGNORED_MASK;
 	unsigned int obj_type, fid_mode;
 	u32 umask = 0;
 	int ret;
@@ -1606,8 +1606,11 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	if (mask & ~valid_mask)
 		return -EINVAL;
 
-	/* Event flags (ONDIR, ON_CHILD) are meaningless in ignored mask */
-	if (ignored)
+	/*
+	 * Event flags (FAN_ONDIR, FAN_EVENT_ON_CHILD) have no effect with
+	 * FAN_MARK_IGNORED_MASK.
+	 */
+	if (ignore)
 		mask &= ~FANOTIFY_EVENT_FLAGS;
 
 	f = fdget(fanotify_fd);
@@ -1721,7 +1724,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 		 * events with parent/name info for non-directory.
 		 */
 		if ((fid_mode & FAN_REPORT_DIR_FID) &&
-		    (flags & FAN_MARK_ADD) && !ignored)
+		    (flags & FAN_MARK_ADD) && !ignore)
 			mask |= FAN_EVENT_ON_CHILD;
 	}