expfs: Fix exportfs_can_encode_fh() for EXPORT_FH_FID

After commit 5402c4d4d200 ("exportfs: require ->fh_to_parent() to encode
connectable file handles") we will fail to create non-decodable file
handles for filesystems without export operations. Fix it.

Fixes: 5402c4d4d200 ("exportfs: require ->fh_to_parent() to encode connectable file handles")
Reviewed-by: Christian Brauner <[e-mail]>
Reviewed-by: Amir Goldstein <[e-mail]>
Signed-off-by: Jan Kara <[e-mail]>

include/linux/exportfs.h

···
 static inline bool exportfs_can_encode_fh(const struct export_operations *nop,
 					  int fh_flags)
 {
-	if (!nop)
-		return false;
-
 	/*
 	 * If a non-decodeable file handle was requested, we only need to make
 	 * sure that filesystem did not opt-out of encoding fid.
 	 */
 	if (fh_flags & EXPORT_FH_FID)
 		return exportfs_can_encode_fid(nop);
+
+	/* Normal file handles cannot be created without export ops */
+	if (!nop)
+		return false;
 
 	/*
 	 * If a connectable file handle was requested, we need to make sure that