1 files changed, 25 insertions, 7 deletions

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index bd99430a128d..9b32b76a9c30 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1081,8 +1081,28 @@ static int fanotify_remove_inode_mark(struct fsnotify_group *group,
 				    flags, umask);
 }
 
+static void fanotify_mark_add_ignored_mask(struct fsnotify_mark *fsn_mark,
+					   __u32 mask, unsigned int flags,
+					   __u32 *removed)
+{
+	fsn_mark->ignored_mask |= mask;
+
+	/*
+	 * 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.
+	 */
+	if ((flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
+	    !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) {
+		fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
+		if (!(fsn_mark->mask & FS_MODIFY))
+			*removed = FS_MODIFY;
+	}
+}
+
 static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
-				       __u32 mask, unsigned int flags)
+				       __u32 mask, unsigned int flags,
+				       __u32 *removed)
 {
 	__u32 oldmask, newmask;
 
@@ -1091,9 +1111,7 @@ static __u32 fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
 	if (!(flags & FAN_MARK_IGNORED_MASK)) {
 		fsn_mark->mask |= mask;
 	} else {
-		fsn_mark->ignored_mask |= mask;
-		if (flags & FAN_MARK_IGNORED_SURV_MODIFY)
-			fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
+		fanotify_mark_add_ignored_mask(fsn_mark, mask, flags, removed);
 	}
 	newmask = fsnotify_calc_mask(fsn_mark);
 	spin_unlock(&fsn_mark->lock);
@@ -1156,7 +1174,7 @@ static int fanotify_add_mark(struct fsnotify_group *group,
 			     __kernel_fsid_t *fsid)
 {
 	struct fsnotify_mark *fsn_mark;
-	__u32 added;
+	__u32 added, removed = 0;
 	int ret = 0;
 
 	mutex_lock(&group->mark_mutex);
@@ -1179,8 +1197,8 @@ static int fanotify_add_mark(struct fsnotify_group *group,
 			goto out;
 	}
 
-	added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
-	if (added & ~fsnotify_conn_mask(fsn_mark->connector))
+	added = fanotify_mark_add_to_mask(fsn_mark, mask, flags, &removed);
+	if (removed || (added & ~fsnotify_conn_mask(fsn_mark->connector)))
 		fsnotify_recalc_mask(fsn_mark->connector);
 
 out: