Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S934396AbcCIXIv (ORCPT <rfc822;w@1wt.eu>);
	Wed, 9 Mar 2016 18:08:51 -0500
Received: from imap.thunk.org ([74.207.234.97]:53400 "EHLO imap.thunk.org"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1754227AbcCIXIl (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Wed, 9 Mar 2016 18:08:41 -0500
Date: Wed, 9 Mar 2016 18:08:19 -0500
From: "Theodore Ts'o" <tytso@mit.edu>
To: Gregory Farnum <greg@gregs42.com>
Cc: Dave Chinner <david@fromorbit.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Christoph Hellwig <hch@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        "Darrick J. Wong" <darrick.wong@oracle.com>,
        Jens Axboe <axboe@kernel.dk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linux API <linux-api@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        shane.seymour@hpe.com, Bruce Fields <bfields@fieldses.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Jeff Layton <jlayton@poochiereds.net>
Subject: Re: [PATCH 2/2] block: create ioctl to discard-or-zeroout a range of
 blocks
Message-ID: <20160309230819.GB3949@thunk.org>
Mail-Followup-To: Theodore Ts'o <tytso@mit.edu>,
	Gregory Farnum <greg@gregs42.com>,
	Dave Chinner <david@fromorbit.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Christoph Hellwig <hch@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	Jens Axboe <axboe@kernel.dk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux API <linux-api@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	shane.seymour@hpe.com, Bruce Fields <bfields@fieldses.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Jeff Layton <jlayton@poochiereds.net>
References: <20160302040947.16685.42926.stgit@birch.djwong.org>
 <CA+55aFx_NPn0VYk=+Ad5S_r=D6J1xFmWmf7JzQ7RmkwKmdkYOg@mail.gmail.com>
 <20160302225601.GB21890@birch.djwong.org>
 <CA+55aFyNPnjJ-Nsu3bMr+HuLQnkj1B8FMddNnXW7HJqxdUzJmQ@mail.gmail.com>
 <yq1bn6v8mqg.fsf@sermon.lab.mkp.net>
 <20160303180924.GA4116@infradead.org>
 <yq1vb5375oh.fsf@sermon.lab.mkp.net>
 <20160303223952.GE24012@thunk.org>
 <20160303231050.GU29057@dastard>
 <CAC6JEv-HeAoRxSmVghGvbX7G92yH00k-5F-48qEW13vAB1Q99g@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAC6JEv-HeAoRxSmVghGvbX7G92yH00k-5F-48qEW13vAB1Q99g@mail.gmail.com>
User-Agent: Mutt/1.5.24 (2015-08-30)
X-SA-Exim-Connect-IP: <locally generated>
X-SA-Exim-Mail-From: tytso@thunk.org
X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 1215
Lines: 24

On Wed, Mar 09, 2016 at 02:20:31PM -0800, Gregory Farnum wrote:
> I really am sensitive to the security concerns, just know that if it's
> a permanent blocker you're essentially blocking out a growing category
> of disk users (who run on an awfully large number of disks!).

Or they just have to use kernels with out-of-tree patches installed.  :-P

If you want to consider how many disks Google has that are using this
patch, I probably could have appealed to Linus and asked him to accept
the patch if I forced the issue.  The only reason why I didn't was
that people like Ric Wheeler threatened to have distro-specific
patches to disable the feature, and at the end of the day, I didn't
care that much.  After all, if it makes it harder for large scale
cloud companies besides Google to create more efficient userspace
cluster file systems, it's not like I was keeping the patch a secret.

So ultimately, if the Ceph developers want to make a case to Red Hat
management that this is important, great.  If not, it's not that hard
for those people who need the patch and who are running large cloud
infrastructures to simply apply the out-of-tree patch if they need it.

Cheers,

   	     	     	 	      		  - Ted