Re: [PATCH v1 3/9] exfat: reuse cache to improve exfat_get_cluster

[Chi Zhiling]

On 12/30/25 17:05, Yuezhang.Mo@xxxxxxxx wrote:
> > -             if (exfat_ent_get(sb, *dclus, &content, NULL))
> > -                     return -EIO;
> > +             if (exfat_ent_get(sb, *dclus, &content, &bh))
> > +                     goto err;
>
> As you commented,  the buffer_head needs release if no error return.
> Here, an error was returned, buffer_head had been released.


I mean, it seems like a duplicate release in there, but in fact it's not.

When exfat_ent_get return an error, *bh is released and set to NULL. So 
the second brelse() call in exfat_get_cluster() does nothing.

~~~
int exfat_ent_get(struct super_block *sb, unsigned int loc,
                unsigned int *content, struct buffer_head **last)
{

	...

err:
        if (last) {
                brelse(*last);

                /* Avoid double release */
                *last = NULL;
        }
        return -EIO;
}
~~~

The reason using "goto err" is that I want to handle all errors in the 
same way. Although this does seem a bit strange and confusing with the 
comment in exfat_ent_get.


Thank,

> >   
> >                *last_dclus = *dclus;
> >                *dclus = content;
> > @@ -299,7 +300,7 @@ int exfat_get_cluster(struct inode *inode, unsigned int cluster,
> >                                exfat_fs_error(sb,
> >                                       "invalid cluster chain (i_pos %u, last_clus 0x%08x is EOF)",
> >                                       *fclus, (*last_dclus));
> > -                             return -EIO;
> > +                             goto err;
> >                        }
> >
> >                        break;
> > @@ -309,6 +310,10 @@ int exfat_get_cluster(struct inode *inode, unsigned int cluster,
> >                        cache_init(&cid, *fclus, *dclus);
> >        }
> >
> > +     brelse(bh);
> >        exfat_cache_add(inode, &cid);
> >        return 0;
> > +err:
> > +     brelse(bh);
> > +     return -EIO;
> >   }