From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B55A4C001DF for ; Mon, 31 Jul 2023 05:55:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230001AbjGaFzw (ORCPT ); Mon, 31 Jul 2023 01:55:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229905AbjGaFzt (ORCPT ); Mon, 31 Jul 2023 01:55:49 -0400 Received: from todd.t-8ch.de (todd.t-8ch.de [IPv6:2a01:4f8:c010:41de::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28A9AE78 for ; Sun, 30 Jul 2023 22:55:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=t-8ch.de; s=mail; t=1690782940; bh=5QtzLncJjPW1Z/AkFRqT4LJ0AxsIBfsBfMzg9sLfXXk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dT5hcPdNviYg1RTXNOZr9ggglMMLfYCZ0Jgd8l71USkoTJGPL2oyYHZbnc13fZsW3 WegPenPnplrg7Rjfidz2L45ijqgSdjclkGlKLyFdoAYmR5hbgw+l1Ih2zTy93x0lcn 1E9gZ9DOUYnc4PPlRBtBHJ60odnmBXtbe/3WQYfk= Date: Mon, 31 Jul 2023 07:55:39 +0200 From: Thomas =?utf-8?Q?Wei=C3=9Fschuh?= To: tjcw@cantab.net Cc: linux-kernel@vger.kernel.org Subject: Re: vfat file system does not allow a space at the end of a directory name Message-ID: <196f7191-5820-4480-99d3-e7ffc66e9c98@t-8ch.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Chris, On 2023-07-30 23:33:03+0100, Chris Ward wrote: > I had a zip file (from downloading pictures from Google Photos) where > some of the directory names had a space at the end. This unzipped fine > on an ext4 file system, but gave errors when unpacking onto a USB key > which had a FAT file system. > > On further investigation, file names have the same problem. On my USB key, I get > > tjcw@tjcw-OptiPlex-7010:/media/tjcw/Photos$ touch 'aab ' > touch: setting times of 'aab ': No such file or directory > tjcw@tjcw-OptiPlex-7010:/media/tjcw/Photos$ echo ok >'aab ' > bash: aab : Invalid argument > tjcw@tjcw-OptiPlex-7010:/media/tjcw/Photos$ touch 'aab' > tjcw@tjcw-OptiPlex-7010:/media/tjcw/Photos$ echo ok >'aab' > tjcw@tjcw-OptiPlex-7010:/media/tjcw/Photos$ > > Is this as expected, or is it a bug in the kernel's handling of FAT > file systems ? Probably the next step is to check the behaviour under > Microsoft Windows. AFAIK this is a limitation in the FAT filesystem itself. The problem is that FAT stores filenames in fixed width fields. Unused space in these fields is filled with ' '. This means that storing "foo", "foo " or "foo ". would all result in the exact same result and it will be impossible to figure out the correct one afterwards. >From Wikipedia [0]: trailing spaces in either the base name or the extension are considered to be padding and not a part of the file name >From fs/fat/namei_vfat.c vfat_is_used_badchars(): last character cannot be space [0] https://en.wikipedia.org/wiki/Design_of_the_FAT_file_system