From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:42002 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753971AbeCFWyC (ORCPT ); Tue, 6 Mar 2018 17:54:02 -0500 Subject: Re: ext4 confusion To: Randy Dunlap , Dave Chinner Cc: linux-ext4@vger.kernel.org, Linux FS Devel References: <9fcee669-1ab3-7beb-a9e8-77fd22dc71c9@infradead.org> <6afdb644-d940-928a-96be-b926a2d32056@redhat.com> <42504c61-393b-6c34-7a01-b82dd0d9064f@infradead.org> <40a6370f-cd2c-094e-e497-33996700cf06@redhat.com> <6d0480b3-e201-bdad-3880-103a1fb93c7f@redhat.com> <22af62e2-81c7-ad6a-07bd-a05c42ba003a@infradead.org> <20180306064759.GI18129@dastard> <487e9ae8-8012-1cbb-9f38-b37777be6585@infradead.org> From: Eric Sandeen Message-ID: <4a159529-eb30-bccc-a865-9c6577018c11@redhat.com> Date: Tue, 6 Mar 2018 16:53:59 -0600 MIME-Version: 1.0 In-Reply-To: <487e9ae8-8012-1cbb-9f38-b37777be6585@infradead.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 3/6/18 2:07 PM, Randy Dunlap wrote: > On 03/05/2018 10:47 PM, Dave Chinner wrote: >> On Mon, Mar 05, 2018 at 09:12:03PM -0800, Randy Dunlap wrote: >>> On 03/05/2018 08:45 PM, Eric Sandeen wrote: >>>> On 3/5/18 10:42 PM, Randy Dunlap wrote: >>>>>>> It's a new OS/installer. OpenSUSE Tumbleweed, which is their bleeding edge >>>>>>> rolling updates release. >>>>>> Hrmph. A lot of things go into this behavior, it may not be a kernel change at >>>>>> all that has made it show up now... >>>>> Yes, it could be that wonderful systemd or something else. >>>> >>>> I think I'd pursue a parallel track of bugging SUSE about the issue... ;) >>>> >>>> (I don't think the kernel will ever just downgrade an rw mount request to >>>> ro, or skip an ro->rw transition silently... leaving it ro does seem >>>> like an init bug, but *shrug* init long ago transitioned into deep magic.) >>> >>> More info: :( >>> >>> This problem happens when booting my own custom 4.16-rc3 kernel. >>> If I boot the OpenSUSE-supplied (4.15.7) kernel, the / fs is remounted rw later on. >>> >>> So I'm more or less back to "what am I doing wrong"? >> >> The filesystem probing order has probably changed. mount tries to >> use blkid to determine the filesytem type to use, and if that >> doesn't find a known type it will fall back to trying mounts with >> explicit types as per the filesystem type order listed in >> /proc/filesystems. (it's in the man mount page) Maybe the device >> module hasn't been loaded when blkid runs to probe existing block >> devices? >> >> These sorts of whacky behaviours have occurred for me in the past >> when either userspace behaviour changed, the order of filesystems >> listed in /proc/filesystems or module load order changed. Typically >> it's a difference in kernel config that causes such shenanigans. > > There is also a (big) difference in the $DISTRO using initramfs and my > custom kernel not using one. But in both cases the SATA/AHCI driver is > loaded/ready before ext4fs, so it's still a mystery to me. > > Eric, I tested your patch but it didn't help in my environment. Odd. It's supposed to be silent if ext3 doesn't recognize the features, but ext4 does. Too many moving parts. :/ -Eric