Re: [PATCH 02/10] xfs: improve the code that checks recovered bmap intent items

Darrick J. Wong
2020-12-04T19:57:22Z

On Fri, Dec 04, 2020 at 08:56:38AM -0500, Brian Foster wrote:
> On Thu, Dec 03, 2020 at 05:11:46PM -0800, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> >
> > The code that validates recovered bmap intent items is kind of a mess --
> > it doesn't use the standard xfs type validators, and it doesn't check
> > for things that it should. Fix the validator function to use the
> > standard validation helpers and look for more types of obvious errors.
> >
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > Reviewed-by: Christoph Hellwig <hch@lst.de>
> > ---
> > fs/xfs/xfs_bmap_item.c | 26 +++++++++++++-------------
> > 1 file changed, 13 insertions(+), 13 deletions(-)
> >
> >
> > diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
> > index 555453d0e080..78346d47564b 100644
> > --- a/fs/xfs/xfs_bmap_item.c
> > +++ b/fs/xfs/xfs_bmap_item.c
> ...
> > @@ -448,13 +442,19 @@ xfs_bui_validate(
> > return false;
> > }
> >
> > - if (startblock_fsb == 0 ||
> > - bmap->me_len == 0 ||
> > - inode_fsb == 0 ||
> > - startblock_fsb >= mp->m_sb.sb_dblocks ||
> > - bmap->me_len >= mp->m_sb.sb_agblocks ||
> > - inode_fsb >= mp->m_sb.sb_dblocks ||
> > - (bmap->me_flags & ~XFS_BMAP_EXTENT_FLAGS))
> > + if (!xfs_verify_ino(mp, bmap->me_owner))
> > + return false;
> > +
> > + if (bmap->me_startoff + bmap->me_len <= bmap->me_startoff)
> > + return false;
> > +
> > + if (bmap->me_startblock + bmap->me_len <= bmap->me_startblock)
> > + return false;
> > +
> > + if (!xfs_verify_fsbno(mp, bmap->me_startblock))
> > + return false;
> > +
> > + if (!xfs_verify_fsbno(mp, bmap->me_startblock + bmap->me_len - 1))
> > return false;
>
> If this is going to be a common pattern, I wonder if an
> xfs_verify_extent() or some such helper that covers the above range
> checks would be helpful. Regardless:

Yes. I'll add a new patch to refactor all the bmap extent validators at
the end.

--D

> Reviewed-by: Brian Foster <bfoster@redhat.com>
>
> >
> > return true;
> >
>