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From: Jeff Liu <jeff.liu@oracle.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH] xfs: Add readpage() check up for mmap file at xfs_file_mmap()
Date: Thu, 19 Jul 2012 10:59:37 +0800	[thread overview]
Message-ID: <50077819.5040406@oracle.com> (raw)
In-Reply-To: <20120718151148.GA17374@infradead.org>

On 07/18/2012 11:11 PM, Christoph Hellwig wrote:

> On Wed, Jul 18, 2012 at 10:47:28PM +0800, Jeff Liu wrote:
>> Hello,
>>
>> When studying XFS code, I found xfs_file_mmap() does not check whether a specific file has readpage() or not.
>> Actually, I have no idea of which kind of file does not supply page reading function, but Btrfs/Ext4
>> as well as generic_file_mmap() all do this check at first, do we also need a defense here?
> 
> It's not needed. In generic_file_mmap it might make a little sense as
> any filesystem could use it, but even there's it's questionable because
> ->readpage is the only way to actually supposed mmap when using
> generic_file_mmap.

Now I got it, thanks for the teaching.

Thanks,
-Jeff

> 
> _______________________________________________
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> xfs@oss.sgi.com
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      reply	other threads:[~2012-07-19  3:00 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-18 14:47 [PATCH] xfs: Add readpage() check up for mmap file at xfs_file_mmap() Jeff Liu
2012-07-18 15:11 ` Christoph Hellwig
2012-07-19  2:59   ` Jeff Liu [this message]

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