inotify: Fix fsnotify_mark refcount leak in inotify_update_existing_watch()

euler inclusion
category: bugfix
bugzilla: 10982
CVE: NA
--------------------------------------------------

commit 4d97f7d5 ("inotify: Add flag IN_MASK_CREATE for
inotify_add_watch()") forgot to call fsnotify_put_mark() with
IN_MASK_CREATE after fsnotify_find_mark()

Fixes: 4d97f7d5 ("inotify: Add flag IN_MASK_CREATE for inotify_add_watch()")
Link: https://www.spinics.net/lists/linux-fsdevel/msg140540.htmlReported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NZhangXiaoxu <zhangxiaoxu5@huawei.com>
Reviewed-by: NMiao Xie <miaoxie@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

fs/notify/inotify/inotify_user.c

@@ -519,8 +519,10 @@ static int inotify_update_existing_watch(struct fsnotify_group *group,
 	fsn_mark = fsnotify_find_mark(&inode->i_fsnotify_marks, group);
 	if (!fsn_mark)
 		return -ENOENT;
-	else if (create)
-		return -EEXIST;
+	else if (create) {
+		ret = -EEXIST;
+		goto out;
+	}
 
 	i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark);
 
@@ -547,7 +549,7 @@ static int inotify_update_existing_watch(struct fsnotify_group *group,
 
 	/* return the wd */
 	ret = i_mark->wd;
-
+out:
 	/* match the get from fsnotify_find_mark() */
 	fsnotify_put_mark(fsn_mark);