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Date: Mon, 3 Mar 2014 22:10:14 +0000
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>,
        lkml <linux-kernel@vger.kernel.org>,
        Miklos Szeredi <miklos@szeredi.hu>, "Theodore T'so" <tytso@mit.edu>,
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        Linux-Fsdevel <linux-fsdevel@vger.kernel.org>,
        "J. Bruce Fields" <bfields@citi.umich.edu>,
        Yongzhi Pan <panyongzhi@gmail.com>
Subject: Re: Update of file offset on write() etc. is non-atomic with I/O
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On Mon, Mar 03, 2014 at 02:01:33PM -0800, Linus Torvalds wrote:
> On Mon, Mar 3, 2014 at 1:45 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> >
> > And it looks like you've missed compat counterparts.
> 
> Grr. Yes, I missed them for compat_readv/writev - even though I
> grepped for various users, but I grepped for all the *other* cases (ie
> vfs_{read|write|llseek}). That means that the locker helper can't be
> static to fs/read_write.c. Oh well.

It can - compat read/write/read/writev are also there these days.  I think
that's the only thing you've missed, but I've several more places to trace
before I'll be sure.