From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A096FC3A5A4 for ; Mon, 2 Sep 2019 01:09:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6E95C21881 for ; Mon, 2 Sep 2019 01:09:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=colorremedies-com.20150623.gappssmtp.com header.i=@colorremedies-com.20150623.gappssmtp.com header.b="gszlPlcC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729269AbfIBBJ6 (ORCPT ); Sun, 1 Sep 2019 21:09:58 -0400 Received: from mail-wr1-f44.google.com ([209.85.221.44]:36561 "EHLO mail-wr1-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729169AbfIBBJ6 (ORCPT ); Sun, 1 Sep 2019 21:09:58 -0400 Received: by mail-wr1-f44.google.com with SMTP id y19so12250427wrd.3 for ; Sun, 01 Sep 2019 18:09:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=colorremedies-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=mzYarF0wSA0aGeDbQDpxvqBpthrsExI7uiwtzFUteuY=; b=gszlPlcCJ+omW4IEwykXOBPdLhqJAyYTizly/JgYVA5IKr1ZOdjFr7F6k1foPtrJwz FP5uMzs7wNBoSWa70c810g5+KPk01e5eJh5dCpEoWE1f99EQ2nvW9oTK/vtGNLQvoKFQ oFXiyhQM/RlzFqzWjb7mWl3TcDoZGRm2I34cWcLWFbgDKYUnR+xQjRrJlhGZ79yh63wl n5GtRGqGo5xpk7zptv/lv5EGHeok4tbdd+illVmKrNpfUqiD5kx/OnYcuzawM8vM06US +Y5C2crXWMlpcNE0rZB+ZMdAQB0ZV84wHFAn4fLwPK9sY+tqy6rcVYy3G2ISabck4uGs KQPA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=mzYarF0wSA0aGeDbQDpxvqBpthrsExI7uiwtzFUteuY=; b=YEikdWVtVKkffcop74nt8jYntj3q9092eBS84AEvZ48GqgY3/+C3ytRqxVvQsz0Ay0 hiBXGDK0aWNSdENtTSU+ivWnooUKBHGoE6EkZ5xDCOC34lJjvXAs36vB5QJL7VylOQ94 G/IkFYI3oDurluh0dnqJIc7YNH9orZ8dtso6fNXyPhTVN4xdXvXjfCrb3tGFZsgrIOmi 7+/j4KTC6h2KOlaHjKorDpZBZb2OCGBBob2sZyrgt6pcejgRpUK/CK04+75m4W7J8g5N ZJUHDWV4rMvBlU/hzoEL53riaDoesM0m3Ve3vQiR6YA2Z3dA3EEu6NSF7aAnQ9ytQoA1 WVyg== X-Gm-Message-State: APjAAAXYD69iiBBp1pSX11vIhrUUuswQkHppk9xJmfxQiyXKhg6GwsOc MY7lRnm3Q06lb8Qvc7uHebRUWQ3xr8dTWbIXoPBO5jHk3qSkyw== X-Google-Smtp-Source: APXvYqz9dF5/y1OMhcz+HO0vtXsPFAYSwhfrzLm0MOVGfRQFC6y+GxzQ1KW652Bw0EjPb+u/kBYsc4DRRSI8R7AsSU4= X-Received: by 2002:a5d:448a:: with SMTP id j10mr2590146wrq.82.1567386595819; Sun, 01 Sep 2019 18:09:55 -0700 (PDT) MIME-Version: 1.0 References: <0b7bfde0-0711-cee3-1ed8-a37b1a62bf5e@megavolts.ch> <20190901032855.GA5604@coach> <6590a3f4-891d-2b22-ed43-4d2def43f290@gmail.com> <20190902005201.GA12944@coach> In-Reply-To: <20190902005201.GA12944@coach> From: Chris Murphy Date: Sun, 1 Sep 2019 19:09:44 -0600 Message-ID: Subject: Re: Spare Volume Features To: Btrfs BTRFS Cc: Andrei Borzenkov , Sean Greenslade Content-Type: text/plain; charset="UTF-8" Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org I'm still mostly convinced the policy questions and management should be dealt with a btrfsd userspace daemon. Btrfs kernel code itself tolerates quite a lot of read and write errors, where a userspace service could say, yeah forget that we're moving over to the spare. Also, that user space daemon could handle the spare device while its in spare status. I don't really see why btrfs kernel code needs to know about it. It's reserved for Btrfs but isn't used by Btrfs, until a policy is triggered. Plausibly one of the policies isn't even device failure, but the volume is nearly full. Spares should be assignable to multiple Btrfs volumes. And that too can be managed by this hypothetical daemon. -- Chris Murphy