linux-kernel - post 2.6.21 regression in F

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Date:	Thu, 10 May 2007 14:56:15 -0400
From:	Doug Chapman <doug.chapman@...com>
To:	linux-kernel@...r.kernel.org, bfields@...i.umich.edu,
	hch@...radead.org, doug.chapman@...com
Subject: post 2.6.21 regression in F_GETLK

A recent regression (introduced after 2.6.21) was caught by the LTP test
fcntl11.  It appears that F_GETLK is not properly checking for existing
F_RDLCK and allows taking out a write lock.

This can be demonstrated by either running fcntl11 from the LTP suite or
I have hacked up a much shorter version which demonstrates the issue and
am attaching it.

Using git bisect I came up with this commit as the one that introduced
the issue.  I briefly tried to back this out from the current tree but
appears a lot has change since then so I will need to try that manually.

commit c2fa1b8a6c059dd08a802545fed3badc8df2adc1
Author: J. Bruce Fields <bfields@...i.umich.edu>
Date:   Tue Feb 20 16:10:11 2007 -0500

    locks: create posix-to-flock helper functions

    Factor out a bit of messy code by creating posix-to-flock counterparts
    to the existing flock-to-posix helper functions.

    Cc: Christoph Hellwig <hch@...radead.org>
    Signed-off-by: "J. Bruce Fields" <bfields@...i.umich.edu>

- Doug

View attachment "simple_fcntl_test.c" of type "text/x-csrc" (2114 bytes)