On Mon, 10 Feb 2025, Eric Biggers wrote:
> On Mon, Feb 10, 2025 at 08:57:55AM -0800, Sami Tolvanen wrote:
> > Hi Mikulas,
> >
> > On Mon, Feb 10, 2025 at 7:04 AM Mikulas Patocka <mpatocka@xxxxxxxxxx> wrote:
> > >
> > > Do forward error correction if metadata I/O fails.
> > >
> > > Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
> > >
> > > ---
> > > drivers/md/dm-verity-target.c | 19 +++++++++++++++++--
> > > 1 file changed, 17 insertions(+), 2 deletions(-)
> > >
> > > Index: linux-2.6/drivers/md/dm-verity-target.c
> > > ===================================================================
> > > --- linux-2.6.orig/drivers/md/dm-verity-target.c 2025-02-04 13:52:45.000000000 +0100
> > > +++ linux-2.6/drivers/md/dm-verity-target.c 2025-02-10 15:55:42.000000000 +0100
> > > @@ -324,8 +324,22 @@ static int verity_verify_level(struct dm
> > > &buf, bio->bi_ioprio);
> > > }
> > >
> > > - if (IS_ERR(data))
> > > - return PTR_ERR(data);
> > > + if (IS_ERR(data)) {
> > > + r = PTR_ERR(data);
> > > + data = dm_bufio_new(v->bufio, hash_block, &buf);
> > > + if (IS_ERR(data))
> > > + return r;
> > > + if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_METADATA,
> > > + hash_block, data) == 0) {
> > > + aux = dm_bufio_get_aux_data(buf);
> > > + aux->hash_verified = 1;
> > > + goto release_ok;
> > > + } else {
> > > + dm_bufio_release(buf);
> > > + dm_bufio_forget(v->bufio, hash_block);
> > > + return r;
> > > + }
> > > + }
> >
> > Don't we still have to check for io->in_bh before trying to correct the error?
dm_bufio_get doesn't return an error code. But adding a test for it
doesn't hurt.
> > Overall, it would be nice not to duplicate code here. Should the
> > metadata error correction / handling be moved to a separate function
> > similar to verity_handle_data_hash_mismatch?
> >
>
> It's also incorrect to do this when skip_verified=true, since in that case
> want_digest (which verity_fec_decode() uses) has not been initialized yet.
>
> - Eric
Yes, I changed it to return "1" if "skip_unverified" is set.
Mikulas
