On Fri, Jan 24, 2014 at 08:42:42AM -0500, Brian Foster wrote:
> On 01/23/2014 05:52 PM, Dave Chinner wrote:
> > @@ -2189,6 +2238,59 @@ out_fix:
> > * shortform directory v2 processing routines -- entry verification and
> > * bad entry deletion (pruning).
> > */
> > +static struct xfs_dir2_sf_entry *
> > +shortform_dir2_junk(
> > + struct xfs_mount *mp,
> > + struct xfs_dir2_sf_hdr *sfp,
> > + struct xfs_dir2_sf_entry *sfep,
> > + xfs_ino_t lino,
> > + int *max_size,
> > + int *index,
> > + int *bytes_deleted,
> > + int *ino_dirty)
> > +{
> > + struct xfs_dir2_sf_entry *tmp_sfep;
> > + int tmp_len;
> > + int tmp_elen;
> > +
> > + if (lino == orphanage_ino)
> > + orphanage_ino = 0;
> > + if (no_modify) {
> > + do_warn(_("would junk entry\n"));
> > + return NULL;
>
> Argh, sorry I missed this last time. ;) This looks like a problem. In
> the no_modify case, we return NULL and 'continue' in the caller, which
> skips the loop end logic and leads to bad things.
>
> We could calculate and return the next entry here, but it might be
> cleaner to use a goto instead of continue in the callers and not
> duplicate the logic.
Argh, my bad. I missed that too. As it is, we already calculate the
next entry in this function - tmp_sfep
>
> > + }
> > +
> > + tmp_elen = xfs_dir3_sf_entsize(mp, sfp,
> > + sfep->namelen);
> > + tmp_sfep = (xfs_dir2_sf_entry_t *)
> > + ((__psint_t) sfep + tmp_elen);
> > + tmp_len = *max_size - ((__psint_t) tmp_sfep
> > + - (__psint_t) sfp);
> > + *max_size -= tmp_elen;
> > + *bytes_deleted += tmp_elen;
> > +
> > + memmove(sfep, tmp_sfep, tmp_len);
What this code is doing is moving all the subsequent entries after
the one being junked down over the entry we are junking...
> > +
> > + sfp->count -= 1;
> > + memset((void *)((__psint_t)sfep + tmp_len), 0,
> > + tmp_elen);
And then zeroing the remaining bytes of the region that is no
longer used.
So the no modify check needs to happen after calculating tmp_sfep
and return that...
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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