Re: [PATCH] exfat: speed up iterate/lookup by fixing start point of traversing fat chain

[Hyeongseok Kim]

On 3/18/21 1:07 AM, Sungjong Seo wrote:
> >   /*
> > - * return values:
> > - *   >= 0	: return dir entiry position with the name in dir
> > - *   -ENOENT	: entry with the name does not exist
> > - *   -EIO	: I/O error
> > + * @ei:         inode info of directory
> > + * @p_dir:      input as directory structure in which we search name
> > + *              if found, output as a cluster dir where the name exists
> > + *              if not found, not changed from input
> > + * @num_entries entry size of p_uniname
> > + * @return:
> > + *   >= 0:      dir entry position from output p_dir.dir
> > + *   -ENOENT:   entry with the name does not exist
> > + *   -EIO:      I/O error
> >    */
> >   int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info
> > *ei,
> >   		struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
> > @@ -925,14 +930,16 @@ int exfat_find_dir_entry(struct super_block *sb,
> > struct exfat_inode_info *ei,
> [snip]
>    			hint_stat->clu = p_dir->dir;
> >   			hint_stat->eidx = 0;
> > -			return (dentry - num_ext);
> > +
> > +			exfat_chain_dup(p_dir, &tmp_clu);
> > +			return dentry_in_cluster;
> >   		}
> >   	}
> >
> >   	hint_stat->clu = clu.dir;
> >   	hint_stat->eidx = dentry + 1;
> > -	return dentry - num_ext;
> > +
> > +	exfat_chain_dup(p_dir, &tmp_clu);
> > +	return dentry_in_cluster;
> >   }
> Changing the functionality of exfat find_dir_entry() will affect
> exfat_find() and exfat_lookup(), breaking the concept of ei->dir.dir
> which should have the starting cluster of its parent directory.
>
> Well, is there any missing patch related to exfat_find()?
> It would be nice to modify the caller of this function, exfat_find(),
> so that this change in functionality doesn't affect other functions.
>
> Thanks.
Whoops, it's a bug. I didn't catch that, thanks.
Maybe it could make exfat inode hash problem.
I wanted to reuse current function interface but, it would be better
to add an addtional parameter. I'll fix this in v2.