On Mon, Oct 16, 2017 at 03:37:08PM -0700, Darrick J. Wong wrote:
> On Mon, Oct 16, 2017 at 03:49:21PM +1100, Dave Chinner wrote:
> > On Wed, Oct 11, 2017 at 06:43:26PM -0700, Darrick J. Wong wrote:
> > > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > >
> > > Check the free space information in a directory.
> >
> > ....
> >
> > > +/* Check free space info in a directory leaf1 block. */
> > > +STATIC int
> > > +xfs_scrub_directory_leaf1_bestfree(
> > > + struct xfs_scrub_context *sc,
> > > + struct xfs_da_args *args,
> > > + xfs_dablk_t lblk)
> > > +{
> > > + struct xfs_dir2_leaf_tail *ltp;
> > > + struct xfs_buf *dbp;
> > > + struct xfs_buf *bp;
> > > + struct xfs_mount *mp = sc->mp;
> > > + __be16 *bestp;
> > > + __u16 best;
> > > + int i;
> > > + int error;
> > > +
> > > + /*
> > > + * Read the free space block. The verifier will check for hash
> > > + * value ordering problems and check the stale entry count.
> > > + */
> > > + error = xfs_dir3_leaf_read(sc->tp, sc->ip, lblk, -1, &bp);
> > > + if (!xfs_scrub_fblock_process_error(sc, XFS_DATA_FORK, lblk, &error))
> > > + goto out;
> > > +
> > > + /* Check all the entries. */
> > > + ltp = xfs_dir2_leaf_tail_p(mp->m_dir_geo, bp->b_addr);
> > > + bestp = xfs_dir2_leaf_bests_p(ltp);
> > > + for (i = 0; i < be32_to_cpu(ltp->bestcount); i++, bestp++) {
> > > + best = be16_to_cpu(*bestp);
> > > + if (best == NULLDATAOFF)
> > > + continue;
> >
> > Count stale entries, check if matches hdr->stale ?
>
> This should already be done by xfs_dir3_leaf_read ->
> xfs_dir3_leaf1_read_verify -> __read_verify -> xfs_dir3_leaf_verify ->
> xfs_dir3_leaf_check_int, right?
True. However, it's simple to do and we're already iterating over
all the structures necessary and detecting the case necessary to
check it, so it doesn't hurt and might catch in-core corruptions
before they hit the write verifier?
And it makes it do the same checks as the free_bestfree checks
below....
> > > + if (!xfs_scrub_fblock_process_error(sc, XFS_DATA_FORK, lblk,
> > > + &error))
> > > + continue;
> > > + xfs_scrub_directory_check_freesp(sc, lblk, dbp, best);
> > > + xfs_trans_brelse(sc->tp, dbp);
> > > + }
> > > +out:
> > > + return error;
> > > +}
> > > +
> > > +/* Check free space info in a directory freespace block. */
> > > +STATIC int
> > > +xfs_scrub_directory_free_bestfree(
> > > + struct xfs_scrub_context *sc,
> > > + struct xfs_da_args *args,
> > > + xfs_dablk_t lblk)
> > > +{
> > > + struct xfs_dir3_icfree_hdr freehdr;
> > > + struct xfs_buf *dbp;
> > > + struct xfs_buf *bp;
> > > + __be16 *bestp;
> > > + __be16 best;
> > > + int i;
> > > + int error;
> > > +
> > > + /* Read the free space block */
> > > + error = xfs_dir2_free_read(sc->tp, sc->ip, lblk, &bp);
> > > + if (!xfs_scrub_fblock_process_error(sc, XFS_DATA_FORK, lblk, &error))
> > > + goto out;
> > > +
> > > + /* Check all the entries. */
> > > + sc->ip->d_ops->free_hdr_from_disk(&freehdr, bp->b_addr);
> > > + bestp = sc->ip->d_ops->free_bests_p(bp->b_addr);
> > > + for (i = 0; i < freehdr.nvalid; i++, bestp++) {
> > > + best = be16_to_cpu(*bestp);
> > > + if (best == NULLDATAOFF)
> > > + continue;
> >
> > Count stale entries, check freehdr.nvalid + stale = freehdr.nused?
>
> Aha, yes, that needs to be checked.
>
> Also that for loop needs to be terminated on i < freehdr.nused.
Good catch - I missed that, too :P
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
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