From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from fieldses.org ([173.255.197.46]:56578 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727315AbeIDXUf (ORCPT ); Tue, 4 Sep 2018 19:20:35 -0400 Date: Tue, 4 Sep 2018 14:54:11 -0400 From: "J. Bruce Fields" To: Rogier Wolff Cc: Jeff Layton , =?utf-8?B?54Sm5pmT5Yas?= , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: POSIX violation by writeback error Message-ID: <20180904185411.GA22166@fieldses.org> References: <20180904075347.GH11854@BitWizard.nl> <82ffc434137c2ca47a8edefbe7007f5cbecd1cca.camel@redhat.com> <20180904161203.GD17478@fieldses.org> <20180904162348.GN17123@BitWizard.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20180904162348.GN17123@BitWizard.nl> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, Sep 04, 2018 at 06:23:48PM +0200, Rogier Wolff wrote: > On Tue, Sep 04, 2018 at 12:12:03PM -0400, J. Bruce Fields wrote: > > Well, I think the point was that in the above examples you'd prefer that > > the read just fail--no need to keep the data. A bit marking the file > > (or even the entire filesystem) unreadable would satisfy posix, I guess. > > Whether that's practical, I don't know. > > When you would do it like that (mark the whole filesystem as "in > error") things go from bad to worse even faster. The Linux kernel > tries to keep the system up even in the face of errors. > > With that suggestion, having one application run into a writeback > error would effectively crash the whole system because the filesystem > may be the root filesystem and stuff like "sshd" that you need to > diagnose the problem needs to be read from the disk.... Well, the absolutist position on posix compliance here would be that a crash is still preferable to returning the wrong data. And for the cases 焦晓冬 gives, that sounds right? Maybe it's the wrong balance in general, I don't know. And we do already have filesystems with panic-on-error options, so if they aren't used maybe then maybe users have already voted against that level of strictness. --b.