From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Brian Foster <bfoster@redhat.com>
Cc: sandeen@sandeen.net, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 4/9] xfs_repair: rebuild free space btrees with bulk loader
Date: Fri, 29 May 2020 14:39:37 -0700 [thread overview]
Message-ID: <20200529213937.GT8230@magnolia> (raw)
In-Reply-To: <20200528151044.GC17794@bfoster>
On Thu, May 28, 2020 at 11:10:44AM -0400, Brian Foster wrote:
> On Tue, May 19, 2020 at 06:51:08PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> >
> > Use the btree bulk loading functions to rebuild the free space btrees
> > and drop the open-coded implementation.
> >
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> > libxfs/libxfs_api_defs.h | 3
> > repair/phase5.c | 870 +++++++++++++---------------------------------
> > 2 files changed, 254 insertions(+), 619 deletions(-)
> >
> >
> ...
> > diff --git a/repair/phase5.c b/repair/phase5.c
> > index 8f5e5f59..e69b042c 100644
> > --- a/repair/phase5.c
> > +++ b/repair/phase5.c
> ...
> > @@ -837,268 +567,202 @@ btnum_to_ops(
> ...
> > +static void
> > +init_freespace_cursors(
> > + struct repair_ctx *sc,
> > + xfs_agnumber_t agno,
> > + unsigned int free_space,
> > + unsigned int *nr_extents,
> > + int *extra_blocks,
> > + struct bt_rebuild *btr_bno,
> > + struct bt_rebuild *btr_cnt)
> > {
> > - xfs_agnumber_t i;
> > - xfs_agblock_t j;
> > - struct xfs_btree_block *bt_hdr;
> > - xfs_alloc_rec_t *bt_rec;
> > - int level;
> > - xfs_agblock_t agbno;
> > - extent_tree_node_t *ext_ptr;
> > - bt_stat_level_t *lptr;
> > - xfs_extlen_t freeblks;
> > - const struct xfs_buf_ops *ops = btnum_to_ops(btnum);
> > + unsigned int bno_blocks;
> > + unsigned int cnt_blocks;
> > int error;
> >
> > - ASSERT(btnum == XFS_BTNUM_BNO || btnum == XFS_BTNUM_CNT);
> > -
> > -#ifdef XR_BLD_FREE_TRACE
> > - fprintf(stderr, "in build_freespace_tree, agno = %d\n", agno);
> > -#endif
> > - level = btree_curs->num_levels;
> > - freeblks = 0;
> > + init_rebuild(sc, &XFS_RMAP_OINFO_AG, free_space, btr_bno);
> > + init_rebuild(sc, &XFS_RMAP_OINFO_AG, free_space, btr_cnt);
> >
> > - ASSERT(level > 0);
> > + btr_bno->cur = libxfs_allocbt_stage_cursor(sc->mp,
> > + &btr_bno->newbt.afake, agno, XFS_BTNUM_BNO);
> > + btr_cnt->cur = libxfs_allocbt_stage_cursor(sc->mp,
> > + &btr_cnt->newbt.afake, agno, XFS_BTNUM_CNT);
> >
> > /*
> > - * initialize the first block on each btree level
> > + * Now we need to allocate blocks for the free space btrees using the
> > + * free space records we're about to put in them. Every record we use
> > + * can change the shape of the free space trees, so we recompute the
> > + * btree shape until we stop needing /more/ blocks. If we have any
> > + * left over we'll stash them in the AGFL when we're done.
> > */
> > - for (i = 0; i < level; i++) {
> > - lptr = &btree_curs->level[i];
> > + do {
> > + unsigned int num_freeblocks;
> > +
> > + bno_blocks = btr_bno->bload.nr_blocks;
> > + cnt_blocks = btr_cnt->bload.nr_blocks;
> >
> > - agbno = get_next_blockaddr(agno, i, btree_curs);
> > - error = -libxfs_buf_get(mp->m_dev,
> > - XFS_AGB_TO_DADDR(mp, agno, agbno),
> > - XFS_FSB_TO_BB(mp, 1), &lptr->buf_p);
> > + /* Compute how many bnobt blocks we'll need. */
> > + error = -libxfs_btree_bload_compute_geometry(btr_bno->cur,
> > + &btr_bno->bload, *nr_extents);
> > if (error)
> > do_error(
> ...
> > +_("Unable to compute free space by block btree geometry, error %d.\n"), -error);
> > +
> > + /* Compute how many cntbt blocks we'll need. */
> > + error = -libxfs_btree_bload_compute_geometry(btr_bno->cur,
>
> btr_cnt? ^
Ooops, yes. Fixed.
> > + &btr_cnt->bload, *nr_extents);
> > + if (error)
> > + do_error(
> > +_("Unable to compute free space by length btree geometry, error %d.\n"), -error);
> > +
> > + /* We don't need any more blocks, so we're done. */
> > + if (bno_blocks >= btr_bno->bload.nr_blocks &&
> > + cnt_blocks >= btr_cnt->bload.nr_blocks)
> > + break;
> > +
> > + /* Allocate however many more blocks we need this time. */
> > + if (bno_blocks < btr_bno->bload.nr_blocks)
> > + setup_rebuild(sc->mp, agno, btr_bno,
> > + btr_bno->bload.nr_blocks - bno_blocks);
> > + if (cnt_blocks < btr_cnt->bload.nr_blocks)
> > + setup_rebuild(sc->mp, agno, btr_cnt,
> > + btr_cnt->bload.nr_blocks - cnt_blocks);
>
> Hmm, I find the setup_rebuild() name a little confusing when seeing an
> init_rebuild() used in the same function. The difference is not apparent
> at a glance. Could we rename setup_rebuild() to something more specific?
> reserve_blocks() perhaps?
Ok, renamed.
> > +
> > + /* Ok, now how many free space records do we have? */
> > + *nr_extents = count_bno_extents_blocks(agno, &num_freeblocks);
> > + } while (1);
> > +
> > + *extra_blocks = (bno_blocks - btr_bno->bload.nr_blocks) +
> > + (cnt_blocks - btr_cnt->bload.nr_blocks);
> > +}
> > +
> > +static void
> > +get_freesp_data(
> > + struct xfs_btree_cur *cur,
> > + struct extent_tree_node *bno_rec,
> > + xfs_agblock_t *freeblks)
> > +{
> > + struct xfs_alloc_rec_incore *arec = &cur->bc_rec.a;
> > +
> > + arec->ar_startblock = bno_rec->ex_startblock;
> > + arec->ar_blockcount = bno_rec->ex_blockcount;
> > + if (freeblks)
> > + *freeblks += bno_rec->ex_blockcount;
> > +}
> > +
> > +/* Grab one bnobt record. */
> > +static int
> > +get_bnobt_record(
> > + struct xfs_btree_cur *cur,
> > + void *priv)
> > +{
> > + struct bt_rebuild *btr = priv;
> > +
> > + get_freesp_data(cur, btr->bno_rec, btr->freeblks);
> > + btr->bno_rec = findnext_bno_extent(btr->bno_rec);
>
> We should probably check for NULL here even if we don't expect it to
> happen.
>
> Also, this logic where we load the current pointer and get the next had
> my eyes crossed for a bit. Can we just check the pointer state here to
> determine whether to find the first record or the next?
Hm, I did that, and the logic ends up more cluttered looking:
if (cur->bc_btnum == XFS_BTNUM_BNO) {
if (btr->bno_rec == NULL)
btr->bno_rec = findfirst_bno_extent(agno);
else
btr->bno_rec = findnext_bno_extent(btr->bno_rec);
} else {
if (btr->bno_rec == NULL)
btr->bno_rec = findfirst_bcnt_extent(agno);
else
btr->bno_rec = findnext_bcnt_extent(cur->bc_ag.agno,
btr->bno_rec);
}
OTOH I think you do have a good point that splitting the code that sets
bno_rec across three functions is not easy to understand.
> Finally, I notice we duplicate the build_[bno|cnt]bt() functions for
> what amounts to a different get_record() callback specific to the tree
> type. If we also generalize get_record() to use the tree type (it
> already has the cursor), it seems that much of the duplication can be
> reduced and the logic simplified.
Ok, done.
> > + return 0;
> > +}
> > +
> > +/* Rebuild a free space by block number btree. */
> > +static void
> > +build_bnobt(
> > + struct repair_ctx *sc,
> > + xfs_agnumber_t agno,
> > + struct bt_rebuild *btr_bno,
> > + xfs_agblock_t *freeblks)
> > +{
> > + int error;
> > +
> > + *freeblks = 0;
> > + btr_bno->bload.get_record = get_bnobt_record;
> > + btr_bno->bload.claim_block = rebuild_claim_block;
>
> Note that one of these callbacks is introduced in this patch and the
> other in the previous. I've no issue with splitting the patches as noted
> in the previous patch, but these should probably be consistent one way
> or the other.
All the btree types set ->claim_block to rebuild_claim_block, whereas
->get_record is specific to the particular type of btree.
> > + btr_bno->bno_rec = findfirst_bno_extent(agno);
> > + btr_bno->freeblks = freeblks;
> > +
> > + error = -libxfs_trans_alloc_empty(sc->mp, &sc->tp);
> > + if (error)
> > + do_error(
> > +_("Insufficient memory to construct bnobt rebuild transaction.\n"));
> > +
> > + /* Add all observed bnobt records. */
> > + error = -libxfs_btree_bload(btr_bno->cur, &btr_bno->bload, btr_bno);
> > + if (error)
> > + do_error(
> > +_("Error %d while creating bnobt btree for AG %u.\n"), error, agno);
> > +
> > + /* Since we're not writing the AGF yet, no need to commit the cursor */
> > + libxfs_btree_del_cursor(btr_bno->cur, 0);
> > + error = -libxfs_trans_commit(sc->tp);
> > + if (error)
> > + do_error(
> > +_("Error %d while writing bnobt btree for AG %u.\n"), error, agno);
> > + sc->tp = NULL;
> > +}
> > +
> ...
> > @@ -2354,48 +2041,14 @@ build_agf_agfl(
> > freelist[i] = cpu_to_be32(NULLAGBLOCK);
> > }
> >
> > - /*
> > - * do we have left-over blocks in the btree cursors that should
> > - * be used to fill the AGFL?
> > - */
> > - if (bno_bt->num_free_blocks > 0 || bcnt_bt->num_free_blocks > 0) {
> > - /*
> > - * yes, now grab as many blocks as we can
> > - */
> > - i = 0;
> > - while (bno_bt->num_free_blocks > 0 && i < libxfs_agfl_size(mp))
> > - {
> > - freelist[i] = cpu_to_be32(
> > - get_next_blockaddr(agno, 0, bno_bt));
> > - i++;
> > - }
> > -
> > - while (bcnt_bt->num_free_blocks > 0 && i < libxfs_agfl_size(mp))
> > - {
> > - freelist[i] = cpu_to_be32(
> > - get_next_blockaddr(agno, 0, bcnt_bt));
> > - i++;
> > - }
> > - /*
> > - * now throw the rest of the blocks away and complain
> > - */
> > - while (bno_bt->num_free_blocks > 0) {
> > - fsb = XFS_AGB_TO_FSB(mp, agno,
> > - get_next_blockaddr(agno, 0, bno_bt));
> > - error = slab_add(lost_fsb, &fsb);
> > - if (error)
> > - do_error(
> > -_("Insufficient memory saving lost blocks.\n"));
> > - }
> > - while (bcnt_bt->num_free_blocks > 0) {
> > - fsb = XFS_AGB_TO_FSB(mp, agno,
> > - get_next_blockaddr(agno, 0, bcnt_bt));
> > - error = slab_add(lost_fsb, &fsb);
> > - if (error)
> > - do_error(
> > -_("Insufficient memory saving lost blocks.\n"));
> > - }
> > + /* Fill the AGFL with leftover blocks or save them for later. */
> > + i = 0;
>
> How about agfl_idx or something since this variable is passed down into
> a function?
The 'i' variable existed before this patch. I can add a new cleanup to
fix the name...
> > + freelist = xfs_buf_to_agfl_bno(agfl_buf);
> > + fill_agfl(btr_bno, freelist, &i);
> > + fill_agfl(btr_cnt, freelist, &i);
> >
> > + /* Set the AGF counters for the AGFL. */
> > + if (i > 0) {
> > agf->agf_flfirst = 0;
> > agf->agf_fllast = cpu_to_be32(i - 1);
> > agf->agf_flcount = cpu_to_be32(i);
> ...
> > @@ -2650,9 +2283,9 @@ _("unable to rebuild AG %u. Not enough free space in on-disk AG.\n"),
> > /*
> > * set up agf and agfl
> > */
> > - build_agf_agfl(mp, agno, &bno_btree_curs,
> > - &bcnt_btree_curs, freeblks1, extra_blocks,
> > - &rmap_btree_curs, &refcnt_btree_curs, lost_fsb);
> > + build_agf_agfl(mp, agno, &btr_bno, &btr_cnt, freeblks1, extra_blocks,
> > + &rmap_btree_curs, &refcnt_btree_curs, lost_fsb);
> > +
>
> I was trying to figure out what extra_blocks was used for and noticed
> that it's not even used by this function. Perhaps a preceding cleanup
> patch to drop it?
Ok.
> > /*
> > * build inode allocation tree.
> > */
> > @@ -2674,15 +2307,14 @@ _("unable to rebuild AG %u. Not enough free space in on-disk AG.\n"),
> > /*
> > * tear down cursors
> > */
> > - finish_cursor(&bno_btree_curs);
> > - finish_cursor(&ino_btree_curs);
>
> Looks like this one shouldn't be going away here.
Oops, good catch.
--D
> Brian
>
> > + finish_rebuild(mp, &btr_bno, lost_fsb);
> > + finish_rebuild(mp, &btr_cnt, lost_fsb);
> > if (xfs_sb_version_hasrmapbt(&mp->m_sb))
> > finish_cursor(&rmap_btree_curs);
> > if (xfs_sb_version_hasreflink(&mp->m_sb))
> > finish_cursor(&refcnt_btree_curs);
> > if (xfs_sb_version_hasfinobt(&mp->m_sb))
> > finish_cursor(&fino_btree_curs);
> > - finish_cursor(&bcnt_btree_curs);
> >
> > /*
> > * release the incore per-AG bno/bcnt trees so the extent nodes
> >
>
next prev parent reply other threads:[~2020-05-29 21:41 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-20 1:50 [PATCH v5 0/9] xfs_repair: use btree bulk loading Darrick J. Wong
2020-05-20 1:50 ` [PATCH 1/9] xfs_repair: port the online repair newbt structure Darrick J. Wong
2020-05-27 12:15 ` Brian Foster
2020-05-27 22:34 ` Darrick J. Wong
2020-05-28 15:08 ` Brian Foster
2020-05-29 21:01 ` Darrick J. Wong
2020-06-01 12:03 ` Brian Foster
2020-06-02 0:12 ` Darrick J. Wong
2020-05-20 1:50 ` [PATCH 2/9] xfs_repair: remove gratuitous code block in phase5 Darrick J. Wong
2020-05-27 12:15 ` Brian Foster
2020-05-20 1:51 ` [PATCH 3/9] xfs_repair: create a new class of btree rebuild cursors Darrick J. Wong
2020-05-27 12:18 ` Brian Foster
2020-05-27 22:07 ` Darrick J. Wong
2020-05-28 15:09 ` Brian Foster
2020-05-29 21:08 ` Darrick J. Wong
2020-05-20 1:51 ` [PATCH 4/9] xfs_repair: rebuild free space btrees with bulk loader Darrick J. Wong
2020-05-28 15:10 ` Brian Foster
2020-05-29 21:39 ` Darrick J. Wong [this message]
2020-06-01 12:05 ` Brian Foster
2020-06-02 0:21 ` Darrick J. Wong
2020-05-20 1:51 ` [PATCH 5/9] xfs_repair: rebuild inode " Darrick J. Wong
2020-05-28 15:11 ` Brian Foster
2020-05-29 22:18 ` Darrick J. Wong
2020-05-29 22:32 ` Darrick J. Wong
2020-05-20 1:51 ` [PATCH 6/9] xfs_repair: rebuild reverse mapping " Darrick J. Wong
2020-05-20 1:51 ` [PATCH 7/9] xfs_repair: rebuild refcount " Darrick J. Wong
2020-05-20 1:51 ` [PATCH 8/9] xfs_repair: remove old btree rebuild support code Darrick J. Wong
2020-05-20 1:51 ` [PATCH 9/9] xfs_repair: track blocks lost during btree construction via extents Darrick J. Wong
2020-05-28 17:00 ` Brian Foster
2020-05-29 22:19 ` Darrick J. Wong
-- strict thread matches above, loose matches on Subject: below --
2020-05-09 16:31 [PATCH v4 0/9] xfs_repair: use btree bulk loading Darrick J. Wong
2020-05-09 16:32 ` [PATCH 4/9] xfs_repair: rebuild free space btrees with bulk loader Darrick J. Wong
2020-05-14 15:12 ` Brian Foster
2020-05-14 19:53 ` Darrick J. Wong
2020-05-15 11:42 ` Brian Foster
2020-03-04 3:29 [PATCH v3 0/9] xfs_repair: use btree bulk loading Darrick J. Wong
2020-03-04 3:29 ` [PATCH 4/9] xfs_repair: rebuild free space btrees with bulk loader Darrick J. Wong
2020-01-01 1:21 [PATCH v2 0/9] xfs_repair: use btree bulk loading Darrick J. Wong
2020-01-01 1:21 ` [PATCH 4/9] xfs_repair: rebuild free space btrees with bulk loader Darrick J. Wong
2019-10-29 23:45 [PATCH RFC 0/9] xfs_repair: use btree bulk loading Darrick J. Wong
2019-10-29 23:45 ` [PATCH 4/9] xfs_repair: rebuild free space btrees with bulk loader Darrick J. Wong
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