From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from pepin.polanet.pl ([193.34.52.2]:47241 "EHLO pepin.polanet.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750918AbdLSUl5 (ORCPT ); Tue, 19 Dec 2017 15:41:57 -0500 Date: Tue, 19 Dec 2017 21:41:55 +0100 From: Tomasz Pala To: Linux fs Btrfs Subject: Re: Unexpected raid1 behaviour Message-ID: <20171219204155.GB14726@polanet.pl> References: <5A357909.8010206@yandex.ru> <23094.37316.66397.431081@tree.ty.sabi.co.uk> <91965e24-3b94-7334-c249-d8de5f585f29@gmail.com> <20171218194351.GA25245@polanet.pl> <7ff86029-5b0f-1d02-778a-af78c6f3e461@gmail.com> <20171219144644.GA9855@polanet.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-2 In-Reply-To: Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Tue, Dec 19, 2017 at 12:35:20 -0700, Chris Murphy wrote: > with a read only file system. Another reason is the kernel code and > udev rule for device "readiness" means the volume is not "ready" until > all member devices are present. And while the volume is not "ready" > systemd will not even attempt to mount. Solving this requires kernel > and udev work, or possibly a helper, to wait an appropriate amount of Sth like this? I got such problem a few months ago, my solution was accepted upstream: https://github.com/systemd/systemd/commit/0e8856d25ab71764a279c2377ae593c0f2460d8f Rationale is in referred ticket, udev would not support any more btrfs logic, so unless btrfs handles this itself on kernel level (daemon?), that is all that can be done. > time. I also think it's a bad idea to implement automatic degraded > mounts unless there's an API for user space to receive either a push [...] > There is no amount of documentation that makes up for these > deficiencies enough to enable automatic degraded mounts by default. I > would consider it a high order betrayal of user trust to do it. It doesn't have to be default, might be kernel compile-time knob, module parameter or anything else to make the *R*aid work. -- Tomasz Pala