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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 6FCE9C43381 for ; Wed, 13 Mar 2019 17:37:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D3872075C for ; Wed, 13 Mar 2019 17:37:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726727AbfCMRh5 (ORCPT ); Wed, 13 Mar 2019 13:37:57 -0400 Received: from mx2.suse.de ([195.135.220.15]:53584 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726336AbfCMRh4 (ORCPT ); Wed, 13 Mar 2019 13:37:56 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id AD10FAF98; Wed, 13 Mar 2019 17:37:55 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 83086DA875; Wed, 13 Mar 2019 18:39:10 +0100 (CET) Date: Wed, 13 Mar 2019 18:39:09 +0100 From: David Sterba To: Anand Jain Cc: Nikolay Borisov , linux-btrfs@vger.kernel.org Subject: Re: [PATCH 2/2] btrfs: fix vanished compression property after failed set Message-ID: <20190313173909.GE31119@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Anand Jain , Nikolay Borisov , linux-btrfs@vger.kernel.org References: <1552455379-2311-1-git-send-email-anand.jain@oracle.com> <1552455379-2311-2-git-send-email-anand.jain@oracle.com> <4ef1a9bb-141c-c07b-d995-9ac3d0c8f1d2@suse.com> <90b86c08-7c3b-d0b1-a895-ebc45af4c059@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Wed, Mar 13, 2019 at 04:49:54PM +0800, Anand Jain wrote: > > > On 3/13/19 3:22 PM, Nikolay Borisov wrote: > > > > > > On 13.03.19 г. 9:20 ч., Nikolay Borisov wrote: > >> > >> > >> On 13.03.19 г. 7:36 ч., Anand Jain wrote: > >>> The compression property resets to NULL, instead of the old value if we > >>> fail to set the new compression parameter. > >>> > >>> btrfs prop get /btrfs compression > >>> compression=lzo > >>> btrfs prop set /btrfs compression zli > >>> ERROR: failed to set compression for /btrfs: Invalid argument > >>> btrfs prop get /btrfs compression > >>> > >>> This is because the compression property ->validate() is successful for > >>> 'zli' as the strncmp() used the len passed from the userland. > >>> > >>> Fix it by using the expected string length in strncmp(). > >>> > >>> Signed-off-by: Anand Jain > >>> --- > >>> fs/btrfs/props.c | 6 +++--- > >>> 1 file changed, 3 insertions(+), 3 deletions(-) > >>> > >>> diff --git a/fs/btrfs/props.c b/fs/btrfs/props.c > >>> index ef6502a94712..7aa362c2fbcf 100644 > >>> --- a/fs/btrfs/props.c > >>> +++ b/fs/btrfs/props.c > >>> @@ -277,11 +277,11 @@ static int prop_compression_validate(struct inode *inode, const char *value, > >>> if (!value) > >>> return 0; > >>> > >>> - if (!strncmp("lzo", value, len)) > >>> + if (!strncmp("lzo", value, 3)) > >>> return 0; > >>> - else if (!strncmp("zlib", value, len)) > >>> + else if (!strncmp("zlib", value, 4)) > >>> return 0; > >>> - else if (!strncmp("zstd", value, len)) > >>> + else if (!strncmp("zstd", value, 4)) > >>> return 0; > >> > >> This also makes the len argument to prop_compression_validate redundant > >> and should be removed as well. > > Its part of the 'struct prop_handler', its better to keep it until > properties have completely evolved. > > > > > As a matter of fact I don't see any value in prop_compression_validate > > since the exact same code is used in prop_compression_apply and einval > > will be returned if an invalid value is passed in. > > I notice too. But its better to keep it until the most of the > properties have evolved. > > As of now btrfs_set_prop() follows sequence.. > h->validate(prop) > setxattr(prop) > h->apply(prop) > > If validate fails its easy to fail exit. Agreed, some code could be repeated in the apply() callback, but otherwise I'd like to keep both.