From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from plane.gmane.org ([80.91.229.3]:60693 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751311AbcEDJyr (ORCPT ); Wed, 4 May 2016 05:54:47 -0400 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1axtVx-0006KT-25 for linux-btrfs@vger.kernel.org; Wed, 04 May 2016 11:54:41 +0200 Received: from ip98-167-165-199.ph.ph.cox.net ([98.167.165.199]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 04 May 2016 11:54:41 +0200 Received: from 1i5t5.duncan by ip98-167-165-199.ph.ph.cox.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 04 May 2016 11:54:41 +0200 To: linux-btrfs@vger.kernel.org From: Duncan <1i5t5.duncan@cox.net> Subject: Re: Subvolumes cannot be mounted after raid1 conversion Date: Wed, 4 May 2016 09:54:28 +0000 (UTC) Message-ID: References: <983F0471-51E8-47EC-B5A0-FBA9040F634B@hagenjohansen.dk> <20160503095515.GM7228@carfax.org.uk> <20160503102746.GN7228@carfax.org.uk> <2a657997-6da8-a190-6057-7b5dcb5d70b1@hagenjohansen.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: hasse posted on Tue, 03 May 2016 20:38:14 +0200 as excerpted: > I have found the easy solution. From > https://bbs.archlinux.org/viewtopic.php?id=192991 > > First: > > # systemctl daemon-reload > > followed by: > > # systemctl restart remote-fs.target > > or > > # systemctl restart local-fs.target > > depending on filesystem type > > I still think it is pretty stupid that systemd doesn't monitor > /etc/fstab (when choosing to create it own secret files) :) Indeed. And thanks for that hint about what to restart. It will likely save me some time when I look into things in a bit more detail, here. =:^) FWIW, my pet gripe about systemd filesystem via fstab handling is... I have several levels of backup mountable from fstab, for example, the first backup root which is also btrfs raid1 on different partitions on the same pair of ssds as my primary btrfs raid1 root, and a second and third backup roots that are still reiserfs on spinning rust. Similarly for home, the media partition, the distro updates tree and (since it's gentoo) build machinery partition, etc. But while I have different mountpoints for the backups based on whether they're of root/home/media/packages, all root backups, for instance, share the same root-backup mountpoint, as there's little reason for me to mount more than one backup of a particular type at a time (and a big reason not to, since in theory that endangers more than one at a time should something go wrong). I mount by label and all the fstab lines have different LABEL= first-fields, so it's fine, and has worked well for me for years now. But at boot and every time I run systemctl daemon-reload or daemon-reexec (the latter of which I often run after updates that affected some library that systemd uses, so it's not running the old version and I can ultimately remount my / readonly again, as it is by default and except when updating), systemd complains about it, because its *.mount unit files are named after the mountpoint, and the multiple fstab entries for the same mountpoint means it tries to create multiple identically named mount unit files. The systemd devs are very aware of the problem as I've seen discussion of it elsewhere, but their policy is simply only one fstab entry per mountpoint, and they see the failure to support more as a feature, not a bug. I've always thought if I got bored I might post a message on the systemd discussion list and ask what their recommendation is, for people that don't want to uselessly track all those extra mount points for multiple levels of backup but still want the convenience of having the entries in fstab, so feeding mount just the LABEL= line works (as does the mountpoint for just mounting the first/default entry), just to see what sort of recommendation they'd have, but I know better than to think that I'd get them to change the policy and call systemd's failure to support the multiple fstab entries for a single mountpoint feature a bug, instead of a feature. Oh, well... As long as it still works in practice, as it has so far, systemd complaining every time I reload it, isn't going to hurt me. But if it stops working, get out the torches and pitchforks! =:^) -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman