From: majianpeng <majianpeng@gmail.com>
To: "konrad.wilk" <konrad.wilk@oracle.com>
Cc: axboe <axboe@kernel.dk>, shaggy <shaggy@kernel.org>,
"chris.mason" <chris.mason@fusionio.com>,
elder <elder@kernel.org>, tytso <tytso@mit.edu>,
ocfs2-devel <ocfs2-devel@oss.oracle.com>,
mfasheh <mfasheh@suse.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
xfs <xfs@oss.sgi.com>, bpm <bpm@sgi.com>,
"adilger.kernel" <adilger.kernel@dilger.ca>,
viro <viro@ZenIV.linux.org.uk>,
jfs-discussion <jfs-discussion@lists.sourceforge.net>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-ext4 <linux-ext4@vger.kernel.org>,
linux-btrfs <linux-btrfs@vger.kernel.org>,
jlbec <jlbec@evilplan.org>
Subject: Re: Re: [PATCH 0/8] Set bi_rw when alloc bio before call bio_add_page.
Date: Tue, 31 Jul 2012 08:42:57 +0800 [thread overview]
Message-ID: <201207310842549068542@gmail.com> (raw)
In-Reply-To: 20120730153935.GE4547@phenom.dumpdata.com
On 2012-07-30 23:39 Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Wrote:
>On Mon, Jul 30, 2012 at 03:14:28PM +0800, majianpeng wrote:
>> When exec bio_alloc, the bi_rw is zero.But after calling bio_add_page,
>
>What about submit_bio? That sets the bi_rw as well?
>> it will use bi_rw.
>> Fox example, in functiion __bio_add_page,it will call merge_bvec_fn().
>
>function.
>> The merge_bvec_fn of raid456 will use the bi_rw to judge the merge.
>> >> if ((bvm->bi_rw & 1) == WRITE)
>> >> return biovec->bv_len; /* always allow writes to be mergeable */
>
>So what does that mean? Without this patch what happens?
>
Because bio_alloc, the bi_rw is zero default.But in __bio_add_page, it used bi_rw.
For example: if merge_bvce_fn used bi_rw, but the bi_rw is wrong(if bi_rw is not zero).
So the result may be error.
>>
>>
>> Jianpeng Ma (8):
>
>Can you collapse all of this in just one patch?
Sorry, I think those files are not a subsystem.So i should send separately.
>
>> Evalue bio->bi_rw after calling bio_alloc() and before calling
>
>It is 'evaluate'
>> bio_add_page().
>> Evalue bio->bi_rw after calling bio_alloc() and before calling
>> bio_add_page().
>> Evalue bio->bi_rw after calling bio_alloc() and before calling
>> bio_add_page().
>> Evalue bio->bi_rw after calling bio_alloc() and before calling
>> bio_add_page().
>> Evalue bio->bi_rw after calling bio_alloc() and before calling
>> bio_add_page().
>> Evalue bio->bi_rw after calling bio_alloc() and before calling
>> bio_add_page().
>> Evalue bio->bi_rw after calling bio_alloc() and before calling
>> bio_add_page().
>> Evalue bio->bi_rw after calling bio_alloc() and before calling
>> bio_add_page().
>>
>> block/blk-lib.c | 1 +
>> drivers/block/xen-blkback/blkback.c | 1 +
>
>I am not really sure if that is correct. Does 'submit_bio' not do the
>job properly?
Before call submit_bio, it call bio_add_page.
>
>> fs/btrfs/check-integrity.c | 1 +
>> fs/direct-io.c | 1 +
>> fs/ext4/page-io.c | 1 +
>> fs/jfs/jfs_metapage.c | 1 +
>> fs/ocfs2/cluster/heartbeat.c | 8 +++++---
>> fs/xfs/xfs_aops.c | 2 ++
>> fs/xfs/xfs_buf.c | 1 +
>> 9 files changed, 14 insertions(+), 3 deletions(-)
>>
>> --
>> 1.7.9.5
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next prev parent reply other threads:[~2012-07-31 0:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-30 7:14 [PATCH 0/8] Set bi_rw when alloc bio before call bio_add_page majianpeng
2012-07-30 15:39 ` Konrad Rzeszutek Wilk
2012-07-31 0:42 ` majianpeng [this message]
2012-07-30 21:42 ` Dave Chinner
2012-07-31 0:55 ` majianpeng
2012-07-31 1:14 ` Dave Chinner
2012-08-10 15:23 ` Muthu Kumar
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