ext4: Allow rename to create more than EXT4_LINK_MAX subdirectories

Use EXT4_DIR_LINK_MAX so that rename() can move a directory into new
parent directory without running into the EXT4_LINK_MAX limit.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/namei.c

@@ -2421,7 +2421,7 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
 			goto end_rename;
 		retval = -EMLINK;
 		if (!new_inode && new_dir != old_dir &&
-				new_dir->i_nlink >= EXT4_LINK_MAX)
+		    EXT4_DIR_LINK_MAX(new_dir))
 			goto end_rename;
 	}
 	if (!new_bh) {