Re: [PATCH 2/4] XFS: Return case-insensitive match for dentry cache

[Christoph Hellwig <hch@infradead.org>]

> > +kmem_zone_t	*xfs_name_zone;
> 
> What about just using kmalloc here?  We know the length of the name
> anyway, so there is no point of allocating the maximum possible size.
> 
> >  	error = xfs_iget(dp->i_mount, NULL, inum, 0, 0, ipp, 0);
> > -	if (error)
> > +	if (error) {
> > +		if (ci_match && *ci_match)
> > +			xfs_name_free(name->name);
> >  		goto out;
> > +	}
> 
> All the allocation and freeing for ci_match looks odd and error prone
> to me.  I think the low-level directory code should never allocate
> args->value unless it's explicitly asked for a CI match.  That way
> there's only one place in xfs_ci_lookup to free it either.

Also the low-level name duplication code could be factored out a little
more ala:

/*
 * If a case-insensitive match, allocate a buffer and copy the actual
 * name into the buffer. Return it via args->value.
 */
void xfs_copy_ci_name(struct xfs_da_args *args, const char *name, int namelen)
{
	if (args->return_ci_name && args->cmpresult == XFS_CMP_CASE) {
		args->valuelen = namelen;
		args->value = kmemdup(name, namelen, GFP_NOFS);
		/* error handled in higher layers */
	}
}

Instead of adding args->return_ci_name it might make sense to just
replace the last four chars there with an unsigned short lookup_flags
and just set bits in it.