Re: [PATCH 8/8] xfs: scrub should flag dir/attr offsets that aren't mappable with xfs_dablk_t

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Fri, Jan 04, 2019 at 01:39:31PM -0500, Brian Foster wrote:
> On Mon, Dec 31, 2018 at 06:09:23PM -0800, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > Teach scrub to flag extent maps that exceed the range that can be mapped
> > with a xfs_dablk_t.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> >  fs/xfs/libxfs/xfs_types.c |   11 +++++++++++
> >  fs/xfs/libxfs/xfs_types.h |    1 +
> >  fs/xfs/scrub/bmap.c       |   27 +++++++++++++++++++++++++++
> >  3 files changed, 39 insertions(+)
> > 
> > 
> > diff --git a/fs/xfs/libxfs/xfs_types.c b/fs/xfs/libxfs/xfs_types.c
> > index 3306fc42cfad..8e03e88a2f1a 100644
> > --- a/fs/xfs/libxfs/xfs_types.c
> > +++ b/fs/xfs/libxfs/xfs_types.c
> > @@ -204,3 +204,14 @@ xfs_verify_icount(
> >  	xfs_icount_range(mp, &min, &max);
> >  	return icount >= min && icount <= max;
> >  }
> > +
> > +/* Sanity-checking of dir/attr block offsets. */
> > +bool
> > +xfs_verify_dablk(
> > +	struct xfs_mount	*mp,
> > +	xfs_fileoff_t		dabno)
> > +{
> > +	xfs_dablk_t		max_dablk = -1U;
> > +
> > +	return dabno < max_dablk;
> 
> Should that be <= ?

Yeah.  Thanks for catching that.

/me notes that xfs_repair doesn't seem to check dablk offsets at all.

Anyway, thanks for the review!  I'll resend the patches that need a v2
early next week.

--D

> Brian
> 
> > +}
> > diff --git a/fs/xfs/libxfs/xfs_types.h b/fs/xfs/libxfs/xfs_types.h
> > index 8f02855a019a..704b4f308780 100644
> > --- a/fs/xfs/libxfs/xfs_types.h
> > +++ b/fs/xfs/libxfs/xfs_types.h
> > @@ -188,5 +188,6 @@ bool xfs_internal_inum(struct xfs_mount *mp, xfs_ino_t ino);
> >  bool xfs_verify_dir_ino(struct xfs_mount *mp, xfs_ino_t ino);
> >  bool xfs_verify_rtbno(struct xfs_mount *mp, xfs_rtblock_t rtbno);
> >  bool xfs_verify_icount(struct xfs_mount *mp, unsigned long long icount);
> > +bool xfs_verify_dablk(struct xfs_mount *mp, xfs_fileoff_t off);
> >  
> >  #endif	/* __XFS_TYPES_H__ */
> > diff --git a/fs/xfs/scrub/bmap.c b/fs/xfs/scrub/bmap.c
> > index e1d11f3223e3..a703cd58a90e 100644
> > --- a/fs/xfs/scrub/bmap.c
> > +++ b/fs/xfs/scrub/bmap.c
> > @@ -281,6 +281,31 @@ xchk_bmap_extent_xref(
> >  	xchk_ag_free(info->sc, &info->sc->sa);
> >  }
> >  
> > +/*
> > + * Directories and attr forks should never have blocks that can't be addressed
> > + * by a xfs_dablk_t.
> > + */
> > +STATIC void
> > +xchk_bmap_dirattr_extent(
> > +	struct xfs_inode	*ip,
> > +	struct xchk_bmap_info	*info,
> > +	struct xfs_bmbt_irec	*irec)
> > +{
> > +	struct xfs_mount	*mp = ip->i_mount;
> > +	xfs_fileoff_t		off;
> > +
> > +	if (!S_ISDIR(VFS_I(ip)->i_mode) && info->whichfork != XFS_ATTR_FORK)
> > +		return;
> > +
> > +	if (!xfs_verify_dablk(mp, irec->br_startoff))
> > +		xchk_fblock_set_corrupt(info->sc, info->whichfork,
> > +				irec->br_startoff);
> > +
> > +	off = irec->br_startoff + irec->br_blockcount - 1;
> > +	if (!xfs_verify_dablk(mp, off))
> > +		xchk_fblock_set_corrupt(info->sc, info->whichfork, off);
> > +}
> > +
> >  /* Scrub a single extent record. */
> >  STATIC int
> >  xchk_bmap_extent(
> > @@ -305,6 +330,8 @@ xchk_bmap_extent(
> >  		xchk_fblock_set_corrupt(info->sc, info->whichfork,
> >  				irec->br_startoff);
> >  
> > +	xchk_bmap_dirattr_extent(ip, info, irec);
> > +
> >  	/* There should never be a "hole" extent in either extent list. */
> >  	if (irec->br_startblock == HOLESTARTBLOCK)
> >  		xchk_fblock_set_corrupt(info->sc, info->whichfork,
> >