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=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED autolearn=no 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 262CFC433DB for ; Fri, 19 Feb 2021 16:27:37 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7855A60234 for ; Fri, 19 Feb 2021 16:27:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7855A60234 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:52708 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lD8cx-0000sa-Gr for qemu-devel@archiver.kernel.org; Fri, 19 Feb 2021 11:27:35 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:55702) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lD8QS-0006Xc-UB for qemu-devel@nongnu.org; Fri, 19 Feb 2021 11:14:41 -0500 Received: from mx2.suse.de ([195.135.220.15]:40548) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lD8QQ-0006YG-2n for qemu-devel@nongnu.org; Fri, 19 Feb 2021 11:14:40 -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 B40BCAC6E; Fri, 19 Feb 2021 16:14:34 +0000 (UTC) Received: from localhost (brahms [local]) by brahms (OpenSMTPD) with ESMTPA id 66cfb798; Fri, 19 Feb 2021 16:15:39 +0000 (UTC) From: Luis Henriques To: Miklos Szeredi Subject: Re: [PATCH v2 0/3] virtiofsd: Add options to enable/disable posix acl References: <20210217233046.81418-1-vgoyal@redhat.com> <87pn0wgtsx.fsf@suse.de> <20210219143403.GA3270@redhat.com> Date: Fri, 19 Feb 2021 16:15:38 +0000 In-Reply-To: (Miklos Szeredi's message of "Fri, 19 Feb 2021 16:55:06 +0100") Message-ID: <87im6oghjp.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=195.135.220.15; envelope-from=lhenriques@suse.de; helo=mx2.suse.de X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, UNPARSEABLE_RELAY=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: virtio-fs-list , Stefan Hajnoczi , qemu-devel@nongnu.org, Vivek Goyal , "Dr. David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Miklos Szeredi writes: > On Fri, Feb 19, 2021 at 3:34 PM Vivek Goyal wrote: >> >> On Fri, Feb 19, 2021 at 11:50:54AM +0000, Luis Henriques wrote: >> > Vivek Goyal writes: >> > >> > > Hi, >> > > >> > > This is V2 of the patches. Changes since v1 are. >> > > >> > > - Rebased on top of latest master. >> > > - Took care of Miklos's comments to block acl xattrs if user >> > > explicitly disabled posix acl. >> > > >> > > Luis Henriques reported that fstest generic/099 fails with virtiofs. >> > > Little debugging showed that we don't enable acl support. So this >> > > patch series provides option to enable/disable posix acl support. By >> > > default it is disabled. >> > > >> > > I have run blogbench and pjdfstests with posix acl enabled and >> > > things work fine. >> > > >> > > Luis, can you please apply these patches, and run virtiofsd with >> > > "-o posix_acl" and see if it fixes the failure you are seeing. I >> > > ran the steps you provided manually and it fixes the issue for >> > > me. >> > >> > Sorry for the delay. I've finally tested these patches and they indeed >> > fix the problem I reported. My only question about this fix is why is >> > this option not enabled by default, since this is the documented behavior >> > in acl(5) and umask(2)? In fact, why is this an option at all? >> >> You mean why to not enable acl by default? >> >> I am concerned about performance drop this can lead to because extra >> GETXATTR(system.posix_acl_*) messages which will trigger if acls are enabled. >> And not all users might require these. That's why I preferred to not enable >> acl by default. Those who need it can enable it explicitly. >> >> Another example is xattr support. Due to performance concerns, we don't >> enable xattrs by default either. > > Actually generic xattr is much worse, since there's no caching for > them currently, as opposed to posix acls, which are cached both when > positive and negative. > > If we enable ACL by default in case xattrs are enabled, we should be > safe, I think. Having an option to disable acls still makes sense, > but it's an optional plus. Great, thanks for clarifying that the reason for having these options is really for performance. Anyway, thanks a lot for looking at this and fixing it. Cheers, -- Luis From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luis Henriques References: <20210217233046.81418-1-vgoyal@redhat.com> <87pn0wgtsx.fsf@suse.de> <20210219143403.GA3270@redhat.com> Date: Fri, 19 Feb 2021 16:15:38 +0000 In-Reply-To: (Miklos Szeredi's message of "Fri, 19 Feb 2021 16:55:06 +0100") Message-ID: <87im6oghjp.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Virtio-fs] [PATCH v2 0/3] virtiofsd: Add options to enable/disable posix acl List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Miklos Szeredi Cc: virtio-fs-list , qemu-devel@nongnu.org, Vivek Goyal Miklos Szeredi writes: > On Fri, Feb 19, 2021 at 3:34 PM Vivek Goyal wrote: >> >> On Fri, Feb 19, 2021 at 11:50:54AM +0000, Luis Henriques wrote: >> > Vivek Goyal writes: >> > >> > > Hi, >> > > >> > > This is V2 of the patches. Changes since v1 are. >> > > >> > > - Rebased on top of latest master. >> > > - Took care of Miklos's comments to block acl xattrs if user >> > > explicitly disabled posix acl. >> > > >> > > Luis Henriques reported that fstest generic/099 fails with virtiofs. >> > > Little debugging showed that we don't enable acl support. So this >> > > patch series provides option to enable/disable posix acl support. By >> > > default it is disabled. >> > > >> > > I have run blogbench and pjdfstests with posix acl enabled and >> > > things work fine. >> > > >> > > Luis, can you please apply these patches, and run virtiofsd with >> > > "-o posix_acl" and see if it fixes the failure you are seeing. I >> > > ran the steps you provided manually and it fixes the issue for >> > > me. >> > >> > Sorry for the delay. I've finally tested these patches and they indeed >> > fix the problem I reported. My only question about this fix is why is >> > this option not enabled by default, since this is the documented behavior >> > in acl(5) and umask(2)? In fact, why is this an option at all? >> >> You mean why to not enable acl by default? >> >> I am concerned about performance drop this can lead to because extra >> GETXATTR(system.posix_acl_*) messages which will trigger if acls are enabled. >> And not all users might require these. That's why I preferred to not enable >> acl by default. Those who need it can enable it explicitly. >> >> Another example is xattr support. Due to performance concerns, we don't >> enable xattrs by default either. > > Actually generic xattr is much worse, since there's no caching for > them currently, as opposed to posix acls, which are cached both when > positive and negative. > > If we enable ACL by default in case xattrs are enabled, we should be > safe, I think. Having an option to disable acls still makes sense, > but it's an optional plus. Great, thanks for clarifying that the reason for having these options is really for performance. Anyway, thanks a lot for looking at this and fixing it. Cheers, -- Luis