fuse: fix root dentry initialization

Add missing dentry initialization to root dentry.

Fixes: f75fdf22b0 ("fuse: don't use ->d_time")
Reported-by: Andreas Reis <andreas.reis@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/dir.c

@@ -286,6 +286,11 @@ const struct dentry_operations fuse_dentry_operations = {
 	.d_release	= fuse_dentry_release,
 };
 
+const struct dentry_operations fuse_root_dentry_operations = {
+	.d_init		= fuse_dentry_init,
+	.d_release	= fuse_dentry_release,
+};
+
 int fuse_valid_type(int m)
 {
 	return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||