From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 4D4761388BF for ; Wed, 17 Feb 2016 19:26:56 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 95DCB21C043; Wed, 17 Feb 2016 19:26:47 +0000 (UTC) Received: from mail-io0-f170.google.com (mail-io0-f170.google.com [209.85.223.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id AD44421C00C for ; Wed, 17 Feb 2016 19:26:46 +0000 (UTC) Received: by mail-io0-f170.google.com with SMTP id z135so48737714iof.0 for ; Wed, 17 Feb 2016 11:26:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:content-type; bh=Xx9D7eBx958LEhZzy0xLvSZutYDNPwgqHCrBqQbBbyc=; b=O+iWEYngEdgkeFTQP6tz81axa5/hZN3cYLnboiZSzOk5xR2UdRDYQNQtwuKp9Y8geX GF7fmKG0CXmnPYqPNPr9w/ErE6yZNB06kudDRql2whX9Wc7Jhtyi3QKL6K7dyXI1IcCv Oa+fsX+pWUVe37aDAJkGcLl1ApblaLA6E1GcRPR4qVw/Clt/L7ZYFRrTPIvD031lFfJi ECN09jd8wj8q0Tkf1a+QEkKd30MRGjNauKDmIs466Zoh0pdw3H5B69s/gDgFjaTcQPcU /evuRJsCEYK2+R4zLq0sRbZpjs3TySuXOYUbv0Bj1N3pYdlksIDoNgR+p7+FkiIIR0+R FuPw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:date :message-id:subject:from:to:content-type; bh=Xx9D7eBx958LEhZzy0xLvSZutYDNPwgqHCrBqQbBbyc=; b=ksC8e7yqwU3KRGjH1Q/TUj6vIGI/V3V8JIgMcEP5VQiv0efAdMPF8DzkhA7Grd2kFM WcMlLOZismb7JSsxi7uPMEeDiud6YO+RpvZ1miskxXVn05uUIgflf8LpzCMvCnSfvJw3 gkqPAeMboa/TKJt+igwKwWyQrasAdro5i2Sk6Lc/rr7134tEicwDY/W9MtbC5ytiF6FP VLUaGk4mhGHZnDn4UPkL7JIwujkHdib3DcfHc/0xeYSddFhsk1jVKJzRY3JIlgGLWAJi 6Jk+9dqGdY68vX1P+u5ruTL7kFeORhQ5r/C1WRI2dcn1gqhkLdFi+3PKbEyPjVEeQORV O42Q== X-Gm-Message-State: AG10YORfQPCsmDVqfkhT5XZCpSQJAghUcTnG+6L1pRPdEAsUlXoz+Bfuu10PTffvXPemstRv/X7psXQ2YIZQiA== Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-dev@lists.gentoo.org Reply-to: gentoo-dev@lists.gentoo.org MIME-Version: 1.0 X-Received: by 10.107.29.209 with SMTP id d200mr5053713iod.27.1455737205917; Wed, 17 Feb 2016 11:26:45 -0800 (PST) Sender: freemanrich@gmail.com Received: by 10.64.225.228 with HTTP; Wed, 17 Feb 2016 11:26:45 -0800 (PST) In-Reply-To: <20160217220154.a015124e45e5cbeb0ee701e5@gentoo.org> References: <20160216180533.GB1450@whubbs1.gaikai.biz> <56C3792A.3010602@gentoo.org> <20160217220154.a015124e45e5cbeb0ee701e5@gentoo.org> Date: Wed, 17 Feb 2016 14:26:45 -0500 X-Google-Sender-Auth: HojvvE_i3rUPtiB3KSeUHxNsV2Q Message-ID: Subject: Re: [gentoo-dev] rfc: Does OpenRC really need mount-ro From: Rich Freeman To: gentoo-dev Content-Type: text/plain; charset=UTF-8 X-Archives-Salt: 09149d6d-c475-458b-9cbc-e06682c740cc X-Archives-Hash: 4d41e563a8783b2e63a0d97c0b7ea624 On Wed, Feb 17, 2016 at 2:01 PM, Andrew Savchenko wrote: > 1) NFS v4 shares can't be unmounted if server is unreachable (even > with -f). If filesystem (e.g. /home or /) contains such unmounted > mount points, it can't be unmounted as well, because it is still in > use. This happens quite often if both NFS server and client are > running from UPS on low power event (when AC power failed and > battery is almost empty). Perhaps at least the behavior in this case should be configurable (timeouts, infinite or otherwise). If you can't contact a remote nfs server then I believe it is possible that unwritten changes are in buffers/etc. Depending on circumstances I could see either pausing until the server comes back or discarding changes and powering off could either be the appropriate behavior. Ultimately, anything not on the disk is always at risk, and any filesystem needs to provide for unclean shutdown to be truly robust. A kernel panic/etc could cause loss of all data in buffers without warning. However, barring that we should of course engineer openrc to shut down in the most clean manner possible, and this should include read-only mounts for anything which can't be unmounted. And even systemd+dracut struggles to cleanly unmount NFS roots in the versions I'm running at least, so that is an edge case that doesn't get much testing. -- Rich