[linux-cifs-client] [PATCH 1/3] cifs: Introduce helper to compute length of nls string in bytes

[Günter Kukkukk]

Am Donnerstag, 23. April 2009 schrieb Günter Kukkukk:
> Am Mittwoch, 22. April 2009 schrieb Jeff Layton:
> > On Wed, 22 Apr 2009 02:25:05 +0200
> > Günter Kukkukk <linux at kukkukk.com> wrote:
> > > 
> > > during cleanup of the unicode related stuff we should also have a look
> > > at functions currently located in misc.c
> > >   - cifs_convertUCSpath()
> > >   - cifsConvertToUCS()
> > > 
> > > At the moment cifs_convertUCSpath() contains the following check:
> > > ...
> > > 		/* make sure we do not overrun callers allocated temp buffer */
> > > 		if (j >= (2 * NAME_MAX))
> > > 			break;
> > > ...
> > > Probably both functions should be moved away from misc.c.
> > 
> > Agreed on all counts. For now, we're focused on the cases where we're
> > converting the data from the server to the local charset. After that's
> > resolved we need to fix the other direction as well.
> > 
> > It might make sense to consolidate all of this in a separate file
> > someplace as well.
> > 
> 
> Hi Jeff,
> 
> the function cifs_convertUCSpath() _is_ related to 
> "...we're focused on the cases where we're converting the data from
> the server to the local charset. ....".
> 
> And - it's heavily used.
> Cheers, Günter

just some further notes. 
With "it's heavily used" i didn't mean the number of callers using this
function (only 1 in readdir.c) - i meant "the number of times" cifs_convertUCSpath()
is called in daily usage.... (readdir results)

The current focus was mostly on cifs_strfromUCS_le() - but the _same_ applies
to cifs_convertUCSpath()!

See the following code snippet: 

readdir.c --> static int cifs_get_name_from_search_buf()
....

	if (unicode) {
		/* BB fixme - test with long names */
		/* Note converted filename can be longer than in unicode */
		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR)
			pqst->len = cifs_convertUCSpath((char *)pqst->name,
					(__le16 *)filename, len/2, nlt);
		else
			pqst->len = cifs_strfromUCS_le((char *)pqst->name,
					(__le16 *)filename, len/2, nlt);

....

Cheers, Günter