linux-kernel - Re: [PATCH 2.6.21] udf: Decrement correct link count in udf

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Date:	Tue, 1 May 2007 14:00:49 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Stephen Mollett <molletts@...oo.com>
Cc:	bfennema@...con.csc.calpoly.edu, linux-kernel@...r.kernel.org,
	Jan Kara <jack@....cz>, Dave Hansen <haveblue@...ibm.com>
Subject: Re: [PATCH 2.6.21] udf: Decrement correct link count in udf_rmdir

On Tue, 1 May 2007 19:23:14 +0100
Stephen Mollett <molletts@...oo.com> wrote:

> It appears that a minor thinko occurred in udf_rmdir and the (already-cleared) 
> link count on the directory that is being removed was being decremented 
> instead of the link count on its parent directory. This gives rise to lots of 
> kernel messages similar to:
> 
> UDF-fs warning (device loop1): udf_rmdir: empty directory has nlink != 2 (8)
> 
> when removing directory trees. No other ill effects have been observed but I 
> guess it could theoretically result in the link count overflowing on a very 
> long-lived, much modified directory.
> 
> Signed-off-by: Stephen Mollett <molletts@...oo.com>
> ---
> 
> Patch applies cleanly to latest git snapshot and other recent 2.6 kernels.
> 
> Please CC: me as I'm not currently subscribed to linux-kernel.
> 
> First attempt at formally submitting a kernel patch - apologies if I've cocked 
> something up - please be nice :-)
> 
> 
> --- linux-2.6.21/fs/udf/namei.c.orig	2007-05-01 18:52:02.000000000 +0100
> +++ linux-2.6.21/fs/udf/namei.c	2007-05-01 18:53:00.000000000 +0100
> @@ -878,7 +878,7 @@ static int udf_rmdir(struct inode * dir,
>  			inode->i_nlink);
>  	clear_nlink(inode);
>  	inode->i_size = 0;
> -	inode_dec_link_count(inode);
> +	inode_dec_link_count(dir);
>  	inode->i_ctime = dir->i_ctime = dir->i_mtime = current_fs_time(dir->i_sb);
>  	mark_inode_dirty(dir);
>  

OK, thanks.  git-blame says

9a53c3a7 (Dave Hansen    2006-09-30 23:29:03 -0700  881)        inode_dec_link_count(inode);

This bug is also fixed in Jan's UDF fixes for 2.6.22, but it looks like I
should make your fix a separate thing, with a 2.6.21.x backport.

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