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=-8.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,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 8405BC433E0 for ; Thu, 18 Feb 2021 17:15:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3D05664EC7 for ; Thu, 18 Feb 2021 17:15:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233840AbhBRRO6 (ORCPT ); Thu, 18 Feb 2021 12:14:58 -0500 Received: from mx2.suse.de ([195.135.220.15]:54374 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232296AbhBRQfP (ORCPT ); Thu, 18 Feb 2021 11:35:15 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id E67F5ACF6; Thu, 18 Feb 2021 16:34:33 +0000 (UTC) Received: from localhost (brahms [local]) by brahms (OpenSMTPD) with ESMTPA id edd07b5a; Thu, 18 Feb 2021 16:35:36 +0000 (UTC) From: Luis Henriques To: Amir Goldstein Cc: Jeff Layton , Steve French , Miklos Szeredi , Trond Myklebust , Anna Schumaker , Alexander Viro , "Darrick J. Wong" , Dave Chinner , Greg KH , Nicolas Boichat , Ian Lance Taylor , Luis Lozano , Andreas Dilger , Olga Kornievskaia , Christoph Hellwig , ceph-devel , linux-kernel , CIFS , samba-technical , linux-fsdevel , Linux NFS Mailing List Subject: Re: [PATCH v5] vfs: fix copy_file_range regression in cross-fs copies References: <20210218151752.26710-1-lhenriques@suse.de> Date: Thu, 18 Feb 2021 16:35:36 +0000 In-Reply-To: (Amir Goldstein's message of "Thu, 18 Feb 2021 17:53:33 +0200") Message-ID: <87blchibaf.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Amir Goldstein writes: > On Thu, Feb 18, 2021 at 5:16 PM Luis Henriques wrote: >> >> A regression has been reported by Nicolas Boichat, found while using the >> copy_file_range syscall to copy a tracefs file. Before commit >> 5dae222a5ff0 ("vfs: allow copy_file_range to copy across devices") the >> kernel would return -EXDEV to userspace when trying to copy a file across >> different filesystems. After this commit, the syscall doesn't fail anymore >> and instead returns zero (zero bytes copied), as this file's content is >> generated on-the-fly and thus reports a size of zero. >> >> This patch restores some cross-filesystem copy restrictions that existed >> prior to commit 5dae222a5ff0 ("vfs: allow copy_file_range to copy across >> devices"). Filesystems are still allowed to fall-back to the VFS >> generic_copy_file_range() implementation, but that has now to be done >> explicitly. >> >> nfsd is also modified to fall-back into generic_copy_file_range() in case >> vfs_copy_file_range() fails with -EOPNOTSUPP or -EXDEV. >> >> Fixes: 5dae222a5ff0 ("vfs: allow copy_file_range to copy across devices") >> Link: https://lore.kernel.org/linux-fsdevel/20210212044405.4120619-1-drinkcat@chromium.org/ >> Link: https://lore.kernel.org/linux-fsdevel/CANMq1KDZuxir2LM5jOTm0xx+BnvW=ZmpsG47CyHFJwnw7zSX6Q@mail.gmail.com/ >> Link: https://lore.kernel.org/linux-fsdevel/20210126135012.1.If45b7cdc3ff707bc1efa17f5366057d60603c45f@changeid/ >> Reported-by: Nicolas Boichat >> Signed-off-by: Luis Henriques >> --- >> And v5! Sorry. Sure, it makes sense to go through the all the vfs_cfr() >> checks first. > > You missed my other comment on v4... > > not checking NULL copy_file_range case. Ah, yeah I did missed it. I'll follow up with yet another revision. Cheers, -- Luis