linux-kernel - Re: [PATCH vfat] allow retrieving entries with trailing dots

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Date:	Wed, 10 Mar 2010 23:44:27 +0900
From:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To:	Philippe De Muyter <phdm@...qel.be>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH vfat] allow retrieving entries with trailing dots

Philippe De Muyter <phdm@...qel.be> writes:

> --- a/fs/fat/namei_vfat.c	2009-09-10 00:13:59.000000000 +0200
> +++ b/fs/fat/namei_vfat.c	2010-02-08 02:28:37.010096903 +0100
> @@ -702,9 +702,22 @@
>  static int vfat_find(struct inode *dir, struct qstr *qname,
>  		     struct fat_slot_info *sinfo)
>  {
> -	unsigned int len = vfat_striptail_len(qname);
> +	int err;
> +	unsigned int len;
> +
> +	/* Some combined ethernet + usb external hard drive do not
> +	 * remove the trailing dots when creating entries in ethernet mode.
> +	 * (e.g. Iomega Home Network Hard Drive)
> +	 * Make accessing those entries possible.
> +	 */
> +	err = fat_search_long(dir, qname->name, qname->len, sinfo);
> +	if (!err)
> +		return err;
> +	len = vfat_striptail_len(qname);
>  	if (len == 0)
>  		return -ENOENT;
> +	if (len == qname->len)
> +		return err;
>  	return fat_search_long(dir, qname->name, len, sinfo);
>  }

This would be bad for both (standard and IO-MEGA hack).

This introduces unneeded directory-parse to standard one.  And for
IO-MEGA, this wouldn't provide proper filename handling.

If it wants to handle the tailing-dot as a part of filename, it
shouldn't be able to access to the stripped-dots filename. (For simple
example, I guess you can't do "mv a a." with this patch.)

I'm not still sure if we should include this or not, however, I think
improper/imperfect quick hack wouldn't be acceptable at least.

Thanks.
-- 
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
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