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.
> >
> > ....
> >
> > > diff --git a/fs/xfs/scrub/dir.c b/fs/xfs/scrub/dir.c
> > > index e2a8f90..a41310f 100644
> > > --- a/fs/xfs/scrub/dir.c
> > > +++ b/fs/xfs/scrub/dir.c
> > > @@ -250,6 +250,426 @@ xfs_scrub_dir_rec(
> > > return error;
> > > }
> > >
> > > +/*
> > > + * Is this unused entry either in the bestfree or smaller than all of them?
> > > + * We assume the bestfrees are sorted longest to shortest, and that there
> > > + * aren't any bogus entries.
> >
> > s/We assume/We've already checked/
>
> Ok.
>
> > > + */
> > > +static inline void
> > > +xfs_scrub_directory_check_free_entry(
> > > + struct xfs_scrub_context *sc,
> > > + xfs_dablk_t lblk,
> > > + struct xfs_dir2_data_free *bf,
> > > + struct xfs_dir2_data_unused *dup)
> >
> > ....
> >
> > > + while (ptr < endptr) {
> > > + dup = (struct xfs_dir2_data_unused *)ptr;
> > > + /* Skip real entries */
> > > + if (dup->freetag != cpu_to_be16(XFS_DIR2_DATA_FREE_TAG)) {
> > > + struct xfs_dir2_data_entry *dep;
> > > +
> > > + dep = (struct xfs_dir2_data_entry *)ptr;
> > > + newlen = d_ops->data_entsize(dep->namelen);
> > > + if (newlen <= 0) {
> > > + xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK,
> > > + lblk);
> > > + goto out_buf;
> > > + }
> > > + ptr += newlen;
> > > + if (endptr < ptr)
> > > + xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK,
> > > + lblk);
> > > + continue;
> > > + }
> > > +
> > > + /* Spot check this free entry */
> > > + tag = be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup));
> > > + if (tag != ((char *)dup - (char *)bp->b_addr))
> > > + xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
> > > +
> > > + /*
> > > + * Either this entry is a bestfree or it's smaller than
> > > + * any of the bestfrees.
> > > + */
> > > + xfs_scrub_directory_check_free_entry(sc, lblk, bf, dup);
> > > +
> > > + /* Move on. */
> > > + newlen = be16_to_cpu(dup->length);
> > > + if (newlen <= 0) {
> > > + xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
> > > + goto out_buf;
> > > + }
> > > + ptr += newlen;
> > > + if (endptr < ptr)
> > > + xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
> >
> > I'd prefer this matches the loop logic order. ie.
> >
> > if (ptr >= endptr)
> >
>
> Ok. That check can be lifted out of the loop anyway.
>
> > > + else
> > > + nr_frees++;
> > > + }
> > > +
> > > + /* Did we see at least as many free slots as there are bestfrees? */
> > > + if (nr_frees < nr_bestfrees)
> > > + xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
> > > +out_buf:
> > > + xfs_trans_brelse(sc->tp, bp);
> > > +out:
> > > + return error;
> > > +}
> > > +
> > > +/*
> > > + * Does the free space length in the free space index block ($len) match
> > > + * the longest length in the directory data block's bestfree array?
> > > + * Assume that we've already checked that the data block's bestfree
> > > + * array is in order.
> > > + */
> > > +static inline void
> > > +xfs_scrub_directory_check_freesp(
> >
> > No need for inline here, the compiler will do that automatically if
> > appropriate.
>
> Ok. I'll make it STATIC like everything else here.
>
> > > + struct xfs_scrub_context *sc,
> > > + xfs_dablk_t lblk,
> > > + struct xfs_buf *dbp,
> > > + unsigned int len)
> > > +{
> > > + struct xfs_dir2_data_free *bf;
> > > + struct xfs_dir2_data_free *dfp;
> > > + int offset;
> > > +
> > > + if (len == 0)
> > > + return;
> > > +
> > > + bf = sc->ip->d_ops->data_bestfree_p(dbp->b_addr);
> > > + for (dfp = &bf[0]; dfp < &bf[XFS_DIR2_DATA_FD_COUNT]; dfp++) {
> > > + offset = be16_to_cpu(dfp->offset);
> > > + if (offset == 0)
> > > + break;
> > > + if (len == be16_to_cpu(dfp->length))
> > > + return;
> > > + /* Didn't find the best length in the bestfree data */
> > > + break;
> > > + }
> > > +
> > > + xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, lblk);
> > > +}
> > > +
> > > +/* 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?
>
> >
> > > + error = xfs_dir3_data_read(sc->tp, sc->ip,
> > > + i * args->geo->fsbcount, -1, &dbp);
> > > + 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.
(Er... NAK on that last sentence; it's the documentation that are wrong.)
--D
>
> --D
>
> > Cheers,
> >
> > Dave.
> > --
> > Dave Chinner
> > david@xxxxxxxxxxxxx
> > --
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