On Thu, Jun 18, 2020 at 11:26:17AM -0400, Brian Foster wrote:
> On Mon, Jun 01, 2020 at 09:27:57PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> >
> > Use the btree bulk loading functions to rebuild the refcount btrees
> > and drop the open-coded implementation.
> >
> > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > ---
> > libxfs/libxfs_api_defs.h | 1
> > repair/agbtree.c | 71 ++++++++++
> > repair/agbtree.h | 5 +
> > repair/phase5.c | 341 ++--------------------------------------------
> > 4 files changed, 93 insertions(+), 325 deletions(-)
> >
> >
> ...
> > diff --git a/repair/phase5.c b/repair/phase5.c
> > index 1c6448f4..ad009416 100644
> > --- a/repair/phase5.c
> > +++ b/repair/phase5.c
> ...
> > @@ -817,10 +510,14 @@ build_agf_agfl(
> > cpu_to_be32(btr_rmap->newbt.afake.af_blocks);
> > }
> >
> > - agf->agf_refcount_root = cpu_to_be32(refcnt_bt->root);
> > - agf->agf_refcount_level = cpu_to_be32(refcnt_bt->num_levels);
> > - agf->agf_refcount_blocks = cpu_to_be32(refcnt_bt->num_tot_blocks -
> > - refcnt_bt->num_free_blocks);
> > + if (xfs_sb_version_hasreflink(&mp->m_sb)) {
> > + agf->agf_refcount_root =
> > + cpu_to_be32(btr_refc->newbt.afake.af_root);
> > + agf->agf_refcount_level =
> > + cpu_to_be32(btr_refc->newbt.afake.af_levels);
> > + agf->agf_refcount_blocks =
> > + cpu_to_be32(btr_refc->newbt.afake.af_blocks);
> > + }
>
> It looks like the previous cursor variant (refcnt_bt) would be zeroed
> out if the feature isn't enabled (causing this to zero out the agf
> fields on disk), whereas now we only write the fields when the feature
> is enabled. Any concern over removing that zeroing behavior? Also note
> that an assert further down unconditionally reads the
> ->agf_refcount_root field.
>
> BTW, I suppose the same question may apply to the previous patch as
> well...
I'll double check, but we do memset the AGF (and AGI) to zero before we
start initializing things, so the asserts should be fine even on
!reflink filesystems.
--D
> Brian
>
> >
> > /*
> > * Count and record the number of btree blocks consumed if required.
> > @@ -981,7 +678,7 @@ phase5_func(
> > struct bt_rebuild btr_ino;
> > struct bt_rebuild btr_fino;
> > struct bt_rebuild btr_rmap;
> > - bt_status_t refcnt_btree_curs;
> > + struct bt_rebuild btr_refc;
> > int extra_blocks = 0;
> > uint num_freeblocks;
> > xfs_agblock_t num_extents;
> > @@ -1017,11 +714,7 @@ _("unable to rebuild AG %u. Not enough free space in on-disk AG.\n"),
> >
> > init_rmapbt_cursor(&sc, agno, num_freeblocks, &btr_rmap);
> >
> > - /*
> > - * Set up the btree cursors for the on-disk refcount btrees,
> > - * which includes pre-allocating all required blocks.
> > - */
> > - init_refc_cursor(mp, agno, &refcnt_btree_curs);
> > + init_refc_cursor(&sc, agno, num_freeblocks, &btr_refc);
> >
> > num_extents = count_bno_extents_blocks(agno, &num_freeblocks);
> > /*
> > @@ -1085,16 +778,14 @@ _("unable to rebuild AG %u. Not enough free space in on-disk AG.\n"),
> > sb_fdblocks_ag[agno] += btr_rmap.newbt.afake.af_blocks - 1;
> > }
> >
> > - if (xfs_sb_version_hasreflink(&mp->m_sb)) {
> > - build_refcount_tree(mp, agno, &refcnt_btree_curs);
> > - write_cursor(&refcnt_btree_curs);
> > - }
> > + if (xfs_sb_version_hasreflink(&mp->m_sb))
> > + build_refcount_tree(&sc, agno, &btr_refc);
> >
> > /*
> > * set up agf and agfl
> > */
> > - build_agf_agfl(mp, agno, &btr_bno, &btr_cnt, &btr_rmap,
> > - &refcnt_btree_curs, lost_fsb);
> > + build_agf_agfl(mp, agno, &btr_bno, &btr_cnt, &btr_rmap, &btr_refc,
> > + lost_fsb);
> >
> > build_inode_btrees(&sc, agno, &btr_ino, &btr_fino);
> >
> > @@ -1112,7 +803,7 @@ _("unable to rebuild AG %u. Not enough free space in on-disk AG.\n"),
> > if (xfs_sb_version_hasrmapbt(&mp->m_sb))
> > finish_rebuild(mp, &btr_rmap, lost_fsb);
> > if (xfs_sb_version_hasreflink(&mp->m_sb))
> > - finish_cursor(&refcnt_btree_curs);
> > + finish_rebuild(mp, &btr_refc, lost_fsb);
> >
> > /*
> > * release the incore per-AG bno/bcnt trees so the extent nodes
> >
>
