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Re: splice vs execve lockdep trace.

To: Ben Myers <bpm@xxxxxxx>
Subject: Re: splice vs execve lockdep trace.
From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Date: Wed, 17 Jul 2013 17:17:36 -0700
Cc: Dave Chinner <david@xxxxxxxxxxxxx>, Peter Zijlstra <peterz@xxxxxxxxxxxxx>, Oleg Nesterov <oleg@xxxxxxxxxx>, Linux Kernel <linux-kernel@xxxxxxxxxxxxxxx>, Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>, Dave Jones <davej@xxxxxxxxxx>, xfs@xxxxxxxxxxx
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On Wed, Jul 17, 2013 at 4:40 PM, Ben Myers <bpm@xxxxxxx> wrote:
>>
>> We're still talking at cross purposes then.
>>
>> How the hell do you handle mmap() and page faulting?
>
> __xfs_get_blocks serializes access to the block map with the i_lock on the
> xfs_inode.  This appears to be racy with respect to hole punching.

Would it be possible to just make __xfs_get_blocks get the i_iolock
(non-exclusively)?

Or, alternatively, do it in the readpage() function?

That was what I thought you did anyway. Exactly because of the whole
page faulting issue.

                   Linus

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