Date: Thu, 12 Jun 2003 14:44:18 -0700
From: Andrew Morton <akpm@digeo.com>
To: Dave McCracken <dmccr@us.ibm.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Fix vmtruncate race and distributed filesystem race
Message-Id: <20030612144418.49f75066.akpm@digeo.com>
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Dave McCracken <dmccr@us.ibm.com> wrote:
>
> 
> --On Thursday, June 12, 2003 14:00:14 -0700 Andrew Morton <akpm@digeo.com>
> wrote:
> 
> > And this does require that ->nopage be entered with page_table_lock held,
> > and that it drop it.
> 
> I think that's a worse layer violation than referencing inode in
> do_no_page.  We shouldn't require that the filesystem layer mess with the
> page_table_lock.

Well it is not "worse".  Futzing with i_sem in do_no_page() is pretty gross.
You could add vm_ops->prevalidate() or something if it worries you.

btw, it should be synchronising with
file->f_dentry->d_inode->i_mapping->host->i_sem, not
file->f_dentry->d_inode->i_sem.  do_truncate() also seems to be taking the
(potentially) wrong semaphore.


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