Re: [PATCH 2.6.21] udf: Decrement correct link count in udf_rmdir

From: Andrew Morton
Date: Tue May 01 2007 - 17:01:31 EST


On Tue, 1 May 2007 19:23:14 +0100
Stephen Mollett <molletts@xxxxxxxxx> 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@xxxxxxxxx>
> ---
>
> 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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