On Fri, Jun 19, 2020 at 08:44:19AM -0500, Eric Sandeen wrote: > On 6/19/20 6:16 AM, Lukas Czerner wrote: > > >> The other possibility is that map[i].size is not right and indeed there > >> seems to be a bug in dx_make_map() > >> > >> map_tail->size = le16_to_cpu(de->rec_len); > >> > >> should be > >> > >> map_tail->size = ext4_rec_len_from_disk(de->rec_len, blocksize)); > >> > >> right ? Otherwise with large enough records the size will be smaller > >> than it really is. > >> > >> A quick look at fs/ext4/namei.c reveals couple of places there rec_len > >> is used without the conversion and we should check whether it needs > >> fixing. > >> > >> -Lukas > > > > And indeed the following patch seems to have fixed the issue we were > > seeing. Eric I think that this might be a proper fix. But we still need > > to check the other uses of rec_len to make sure it's ok as well. > > > > diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c > > index 94ec882..5509fdc 100644 > > --- a/fs/ext4/namei.c > > +++ b/fs/ext4/namei.c > > @@ -1068,7 +1068,7 @@ static int dx_make_map(struct ext4_dir_entry_2 *de, unsigned blocksize, > > map_tail--; > > map_tail->hash = h.hash; > > map_tail->offs = ((char *) de - base)>>2; > > - map_tail->size = le16_to_cpu(de->rec_len); > > + map_tail->size = ext4_rec_len_from_disk(le16_to_cpu(de->rec_len), blocksize); > > That isn't right, ext4_rec_len_from_disk /takes/ an __le16 :) > > - map_tail->size = le16_to_cpu(de->rec_len); > + map_tail->size = ext4_rec_len_from_disk(de->rec_len), blocksize); Yep, my bad. > > would be more correct, but won't matter for PAGE_SIZE < 65536 right? True, it's not the problem we're seeing. -Lukas > > -Eric >
