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

[Brian Foster <bfoster@redhat.com>]

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 <= ?

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,
>