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 X-Spam-Level: X-Spam-Status: No, score=-16.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54877C433E6 for ; Sat, 6 Feb 2021 04:21:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1558264F06 for ; Sat, 6 Feb 2021 04:21:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230514AbhBFEVE (ORCPT ); Fri, 5 Feb 2021 23:21:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:42596 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230322AbhBFDME (ORCPT ); Fri, 5 Feb 2021 22:12:04 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3957165016; Sat, 6 Feb 2021 00:05:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1612569953; bh=UShNfZsoBlO05lAQRkPFldQn5CSrPHZ7sGnhQHHXTnk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=WgICwMkady18epyVATi4bMxlwDnjJGnkWlirkeeU6ddtzD4iYENFo+ABGWhYKmzHT W5bRqQ2r3qKjrmp+K2ltce9TZTz34jpR6v2pCmvkfHSSNW2Xth0N1LVn0VfJM0zrSp UJlrejTzImt9N4P+YRM+bQy3O15KMAriMEScCras= Date: Fri, 5 Feb 2021 16:05:51 -0800 From: Andrew Morton To: Seth Forshee Cc: Hugh Dickins , Chris Down , Amir Goldstein , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , linux-mm@kvack.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] tmpfs: Disallow CONFIG_TMPFS_INODE64 on s390 Message-Id: <20210205160551.cf57c4293ba5ccb8eb648c11@linux-foundation.org> In-Reply-To: <20210205230620.518245-1-seth.forshee@canonical.com> References: <20210205230620.518245-1-seth.forshee@canonical.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 5 Feb 2021 17:06:20 -0600 Seth Forshee wrote: > This feature requires ino_t be 64-bits, which is true for every > 64-bit architecture but s390, so prevent this option from being > selected there. > The previous patch nicely described the end-user impact of the bug. This is especially important when requesting a -stable backport. Here's what I ended up with: From: Seth Forshee Subject: tmpfs: disallow CONFIG_TMPFS_INODE64 on s390 Currently there is an assumption in tmpfs that 64-bit architectures also have a 64-bit ino_t. This is not true on s390 which has a 32-bit ino_t. With CONFIG_TMPFS_INODE64=y tmpfs mounts will get 64-bit inode numbers and display "inode64" in the mount options, but passing the "inode64" mount option will fail. This leads to the following behavior: # mkdir mnt # mount -t tmpfs nodev mnt # mount -o remount,rw mnt mount: /home/ubuntu/mnt: mount point not mounted or bad option. As mount sees "inode64" in the mount options and thus passes it in the options for the remount. So prevent CONFIG_TMPFS_INODE64 from being selected on s390. Link: https://lkml.kernel.org/r/20210205230620.518245-1-seth.forshee@canonical.com Fixes: ea3271f7196c ("tmpfs: support 64-bit inums per-sb") Signed-off-by: Seth Forshee Cc: Chris Down Cc: Hugh Dickins Cc: Amir Goldstein Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: [5.9+] Signed-off-by: Andrew Morton --- fs/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/Kconfig~tmpfs-disallow-config_tmpfs_inode64-on-s390 +++ a/fs/Kconfig @@ -203,7 +203,7 @@ config TMPFS_XATTR config TMPFS_INODE64 bool "Use 64-bit ino_t by default in tmpfs" - depends on TMPFS && 64BIT + depends on TMPFS && 64BIT && !S390 default n help tmpfs has historically used only inode numbers as wide as an unsigned _