From: Al Viro <viro@ZenIV.linux.org.uk>
To: Matti Linnanvuori <mattilinnanvuori@yahoo.com>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [patch] fs: remove local variable copy of f_pos to enable thread-safe updates
Date: Fri, 2 May 2008 16:41:00 +0100 [thread overview]
Message-ID: <20080502154100.GF5882@ZenIV.linux.org.uk> (raw)
In-Reply-To: <342069.46185.qm@web52010.mail.re2.yahoo.com>
On Fri, May 02, 2008 at 08:33:50AM -0700, Matti Linnanvuori wrote:
> File systems can be written so that implementations of read, lseek etc.
> acquire a lock before using *pos, which precludes races. That was the
> idea behind my patch. So, my patch does not necessarily cause races.
> read instances can be racy in Linux now because there is no lock to
> serialize read etc. system calls.
Oh, yes it does - current tree guarantees that variable passed to ->read()
will not change under it, so any code that relied on that got broken.
And no, modifying every driver's ->read() is not going to be fun - it's
not just filesystems.
next prev parent reply other threads:[~2008-05-02 15:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-02 15:33 [patch] fs: remove local variable copy of f_pos to enable thread-safe updates Matti Linnanvuori
2008-05-02 15:41 ` Al Viro [this message]
-- strict thread matches above, loose matches on Subject: below --
2008-05-02 9:14 Matti Linnanvuori
2008-05-02 9:33 ` Al Viro
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