Message-ID: <4C57FBAD.1080809@fusionio.com>
Date: Tue, 3 Aug 2010 13:21:17 +0200
From: Jens Axboe <jaxboe@fusionio.com>
MIME-Version: 1.0
To: Tejun Heo <tj@kernel.org>
CC: <stable@kernel.org>, Vladislav Bolkhovitin <vst@vlnb.net>,
        Bryan Mesich <bryan.mesich@ndsu.edu>,
        <scst-devel@lists.sourceforge.net>, <linux-kernel@vger.kernel.org>,
        <linux-raid@vger.kernel.org>, <dm-devel@redhat.com>,
        Neil Brown <neilb@suse.de>
Subject: Re: [PATCH 1/2 block#for-2.6.36] bio, fs: update RWA_MASK, READA
 and  SWRITE to match the corresponding BIO_RW_* bits
References: <20100628010346.GA2376@atlantis.cc.ndsu.nodak.edu>	<4C28EFD6.2070203@vlnb.net>	<20100714190325.GA25148@atlantis.cc.ndsu.nodak.edu>	<4C3EF3AD.5070509@vlnb.net>	<20100723191844.GB31152@atlantis.cc.ndsu.nodak.edu>	<4C4D7DF5.9060909@vlnb.net>	<20100727220110.GF31152@atlantis.cc.ndsu.nodak.edu>	<4C5073F3.1060406@vlnb.net>	<4C52A98A.7060507@kernel.org> <20100802104227.79340b49@notabene> <4C56D397.8010305@kernel.org> <4C5724E8.9010204@kernel.dk> <4C57E722.5060809@kernel.org> <4C57FA57.2000601@kernel.dk>
In-Reply-To: <4C57FA57.2000601@kernel.dk>
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On 2010-08-03 13:15, Jens Axboe wrote:
> On 2010-08-03 11:53, Tejun Heo wrote:
>> Commit a82afdf (block: use the same failfast bits for bio and request)
>> moved BIO_RW_* bits around such that they match up with REQ_* bits.
>> Unfortunately, fs.h hard coded RW_MASK, RWA_MASK, READ, WRITE, READA
>> and SWRITE as 0, 1, 2 and 3, and expected them to match with BIO_RW_*
>> bits.  READ/WRITE didn't change but BIO_RW_AHEAD was moved to bit 4
>> instead of bit 1, breaking RWA_MASK, READA and SWRITE.
>>
>> This patch updates RWA_MASK, READA and SWRITE such that they match the
>> BIO_RW_* bits again.  A follow up patch will update the definitions to
>> directly use BIO_RW_* bits so that this kind of breakage won't happen
>> again.
>>
>> Neil also spotted missing RWA_MASK conversion.
>>
>> Stable: The offending commit a82afdf was released with v2.6.32, so
>> this patch should be applied to all kernels since then but it must
>> _NOT_ be applied to kernels earlier than that.
>>
>> Signed-off-by: Tejun Heo <tj@kernel.org>
>> Reported-and-bisected-by: Vladislav Bolkhovitin <vst@vlnb.net>
>> Root-caused-by: Neil Brown <neilb@suse.de>
>> Cc: Jens Axobe <axboe@kernel.dk>
>            ^^^^^
> 
> (Too) common typo :-)
> 
> Anyway, applied to for-2.6.36, thanks a lot.

Irk, we have an issue:

In file included from fs/coda/psdev.c:48:
include/linux/coda_psdev.h:91:1: warning: "REQ_WRITE" redefined
In file included from include/linux/fs.h:11,
                 from include/linux/proc_fs.h:5,
                 from fs/coda/psdev.c:31:
include/linux/blk_types.h:154:1: warning: this is the location of the previous definition

And from include/linux/coda_psdev.h:

#define REQ_ASYNC  0x1
#define REQ_READ   0x2
#define REQ_WRITE  0x4
#define REQ_ABORT  0x8

which unfortunately seem to not be under __KERNEL__ protection, but
there are things like wait_queue_head_t structs there as well so should
be safe to change.

-- 
Jens Axboe


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