From owner-freebsd-current@freebsd.org  Sat Feb 10 18:50:37 2018
Return-Path: <owner-freebsd-current@freebsd.org>
Delivered-To: freebsd-current@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 86E1FF13932
 for <freebsd-current@mailman.ysv.freebsd.org>;
 Sat, 10 Feb 2018 18:50:37 +0000 (UTC) (envelope-from wjw@digiware.nl)
Received: from smtp.digiware.nl (smtp.digiware.nl [IPv6:2001:4cb8:90:ffff::3])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256
 bits)) (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id 287616BBD9;
 Sat, 10 Feb 2018 18:50:37 +0000 (UTC) (envelope-from wjw@digiware.nl)
Received: from router.digiware.nl (localhost.digiware.nl [127.0.0.1])
 by smtp.digiware.nl (Postfix) with ESMTP id 7BCF72E001;
 Sat, 10 Feb 2018 19:50:28 +0100 (CET)
X-Virus-Scanned: amavisd-new at digiware.com
Received: from smtp.digiware.nl ([127.0.0.1])
 by router.digiware.nl (router.digiware.nl [127.0.0.1]) (amavisd-new,
 port 10024)
 with ESMTP id q9U_E4vEmQ9W; Sat, 10 Feb 2018 19:50:27 +0100 (CET)
Received: from [192.168.11.152] (unknown [192.168.11.152])
 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))
 (No client certificate requested)
 by smtp.digiware.nl (Postfix) with ESMTPSA id BE2D32F000;
 Sat, 10 Feb 2018 19:50:27 +0100 (CET)
Subject: Re: posix_fallocate on ZFS
To: Alan Somers <asomers@freebsd.org>
Cc: freebsd current <freebsd-current@freebsd.org>
References: <1e2f43fd-85da-6629-62d1-6e96790278e5@digiware.nl>
 <CAOtMX2jZr_kvJgOZWeiB-AZ3-7-uUu+UQ3P0nKhGZ0eNRzwMOQ@mail.gmail.com>
From: Willem Jan Withagen <wjw@digiware.nl>
Message-ID: <985b6d77-9f27-f6f4-ea0e-165951d91048@digiware.nl>
Date: Sat, 10 Feb 2018 19:50:28 +0100
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101
 Thunderbird/52.6.0
MIME-Version: 1.0
In-Reply-To: <CAOtMX2jZr_kvJgOZWeiB-AZ3-7-uUu+UQ3P0nKhGZ0eNRzwMOQ@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-GB
Content-Transfer-Encoding: 8bit
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.25
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
 <freebsd-current.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/freebsd-current>, 
 <mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current/>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/freebsd-current>, 
 <mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 10 Feb 2018 18:50:37 -0000

On 10/02/2018 19:24, Alan Somers wrote:
> On Sat, Feb 10, 2018 at 10:28 AM, Willem Jan Withagen <wjw@digiware.nl 
> <mailto:wjw@digiware.nl>> wrote:
> 
>     Hi,
> 
>     This has been disabled on ZFS since last November.
>     And I do understand the rationale on this.
> 
>     BUT
> 
>     I've now upgraded some of my HEAD Ceph test systems and they now
>     fail, since Ceph uses posix_fallocate() to allocate space for the
>     FileStore-journal.
> 
>     Is there any expectation that this is going to fixed in any near future?
> 
>     --WjW
> 
> 
> No.  It's fundamentally impossible to support posix_fallocate on a COW 
> filesystem like ZFS.  Ceph should be taught to ignore an EINVAL result, 
> since the system call is merely advisory.

Yup, that was what I'm going to do.
But then I would like to know how to annotate it.

And I guess that I'd get reactions submitting code to fix this, since 
the journal could run out of space.
So I'd beter know what is going on.

I seem to remember that on a pool level is is possible to reserve space 
whilest creating a filesystem? And then it could/should be fixed when 
building the disk-infra for an OSD.

--WjW