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From: Tejun Heo <tj@kernel.org>
To: Milan Broz <mbroz@redhat.com>
Cc: Tao Ma <tm@tao.ma>,
	linux-kernel@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
	device-mapper development <dm-devel@redhat.com>
Subject: Re: [PATCH] loop: clear read-only flag in loop_clr_fd.
Date: Mon, 14 Feb 2011 15:07:55 +0100	[thread overview]
Message-ID: <20110214140755.GL18742@htj.dyndns.org> (raw)
In-Reply-To: <4D591664.6090203@redhat.com>

Hello, Milan.

On Mon, Feb 14, 2011 at 12:47:48PM +0100, Milan Broz wrote:
> With patch below (loop cannot be built as module) it fixes the loop problem.

Okay.

> But it doesn't fix the read-only snapshot issue and I guess there will be
> the same problem with read-only MD code too.
> (so the 2) issue here https://lkml.org/lkml/2011/2/12/209).
> 
> If the call is changed intentionally, we have to fix unconditional blkdev open
> calls with read-write flag in this code.
> Before doing that I would like to know if it was intentional change or not...

Yeap, the change was intentional.  It was part of effort to make bdev
usages more consistent as before there was no mechanism enforcing ro.
It's still problematic as bdev users can clear ro without consulting
the actual device driver.  Device driver's ->open() is called w/ ro
flag but the resulting bdev can be used rw.  I wanted to remove that
too but filesystems depend on it so maybe later.

Thanks.

-- 
tejun

  parent reply	other threads:[~2011-02-14 14:08 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-13  2:02 block device read-only handling regression in 2.6.38-rc4 (bisected) Milan Broz
2011-02-13 10:58 ` [PATCH] loop: clear read-only flag in loop_clr_fd Tao Ma
2011-02-13 14:11   ` Milan Broz
2011-02-13 15:05     ` Tao Ma
2011-02-13 16:44       ` Milan Broz
2011-02-14 10:30         ` Tejun Heo
2011-02-14 11:47           ` Milan Broz
2011-02-14 13:14             ` [PATCH][RFC] dm: Do not open log and cow device read-write for read-only mappings Milan Broz
2011-02-14 14:09               ` Tejun Heo
2011-02-14 14:23                 ` Milan Broz
2011-02-14 15:44                   ` Tejun Heo
2011-02-14 23:15                     ` NeilBrown
2011-02-15  2:03                       ` [dm-devel] " Alasdair G Kergon
2011-02-15 12:17                         ` Milan Broz
2011-02-15 12:46                           ` Alasdair G Kergon
2011-02-15 15:20                             ` Tejun Heo
2011-02-15 15:46                               ` Alasdair G Kergon
2011-02-15 15:50                                 ` Tejun Heo
2011-02-15 16:05                                   ` Milan Broz
2011-02-15 16:12                                     ` Tejun Heo
2011-02-15 16:36                                       ` Milan Broz
2011-02-15 16:41                                         ` Tejun Heo
2011-02-15 16:56                                           ` Alasdair G Kergon
2011-02-16  8:46                                             ` Tejun Heo
2011-02-15 16:58                                           ` Milan Broz
2011-02-16  8:39                                             ` Tejun Heo
2011-02-15 15:16                           ` [PATCH] Return EROFS if read-only detected on block device Milan Broz
2011-02-14 14:39                 ` [dm-devel] [PATCH][RFC] dm: Do not open log and cow device read-write for read-only mappings Alasdair G Kergon
2011-02-14 14:07             ` Tejun Heo [this message]
     [not found] <glzzr-4Jt-1@gated-at.bofh.it>
     [not found] ` <glHQm-1vQ-25@gated-at.bofh.it>
2011-02-13 20:41   ` [PATCH] loop: clear read-only flag in loop_clr_fd Bodo Eggert

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