[4/9] xfs_repair: rebuild free space btrees with bulk loader
diff mbox series

Message ID 158904192820.984305.12654411837854594801.stgit@magnolia
State Superseded
Headers show
Series
  • xfs_repair: use btree bulk loading
Related show

Commit Message

Darrick J. Wong May 9, 2020, 4:32 p.m. UTC
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          |  858 +++++++++++++---------------------------------
 2 files changed, 247 insertions(+), 614 deletions(-)

Comments

Brian Foster May 14, 2020, 3:12 p.m. UTC | #1
On Sat, May 09, 2020 at 09:32:08AM -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          |  858 +++++++++++++---------------------------------
>  2 files changed, 247 insertions(+), 614 deletions(-)
> 
> 
...
> diff --git a/repair/phase5.c b/repair/phase5.c
> index 7eb24519..94e4610c 100644
> --- a/repair/phase5.c
> +++ b/repair/phase5.c
...
> @@ -465,7 +476,7 @@ _("error - not enough free space in filesystem\n"));
>  
>  /* Feed one of the new btree blocks to the bulk loader. */
>  static int
> -rebuild_alloc_block(
> +rebuild_claim_block(
>  	struct xfs_btree_cur	*cur,
>  	union xfs_btree_ptr	*ptr,
>  	void			*priv)

Hmm.. seems like a decent amount of churn here. The above function is
renamed and finish_rebuild() looks like it's gutted/replaced before
either is ever used. Can we get the core bits settled into the previous
patch(es) so they aren't changing when used to implement the tree
reconstructions?

Brian

> @@ -505,313 +516,32 @@ finish_cursor(bt_status_t *curs)
>  	free(curs->btree_blocks);
>  }
>  
> +/*
> + * Scoop up leftovers from a rebuild cursor for later freeing, then free the
> + * rebuild context.
> + */
>  static void
>  finish_rebuild(
>  	struct xfs_mount	*mp,
> -	struct bt_rebuild	*btr)
> +	struct bt_rebuild	*btr,
> +	struct xfs_slab		*lost_fsb)
>  {
>  	struct xrep_newbt_resv	*resv, *n;
>  
>  	for_each_xrep_newbt_reservation(&btr->newbt, resv, n) {
> -		xfs_agnumber_t	agno;
> -		xfs_agblock_t	bno;
> -		xfs_extlen_t	len;
> -
> -		if (resv->used >= resv->len)
> -			continue;
> -
> -		/* XXX: Shouldn't this go on the AGFL? */
> -		/* Put back everything we didn't use. */
> -		bno = XFS_FSB_TO_AGBNO(mp, resv->fsbno + resv->used);
> -		agno = XFS_FSB_TO_AGNO(mp, resv->fsbno + resv->used);
> -		len = resv->len - resv->used;
> -
> -		add_bno_extent(agno, bno, len);
> -		add_bcnt_extent(agno, bno, len);
> -	}
> -
> -	xrep_newbt_destroy(&btr->newbt, 0);
> -}
> -
> -/*
> - * We need to leave some free records in the tree for the corner case of
> - * setting up the AGFL. This may require allocation of blocks, and as
> - * such can require insertion of new records into the tree (e.g. moving
> - * a record in the by-count tree when a long extent is shortened). If we
> - * pack the records into the leaves with no slack space, this requires a
> - * leaf split to occur and a block to be allocated from the free list.
> - * If we don't have any blocks on the free list (because we are setting
> - * it up!), then we fail, and the filesystem will fail with the same
> - * failure at runtime. Hence leave a couple of records slack space in
> - * each block to allow immediate modification of the tree without
> - * requiring splits to be done.
> - *
> - * XXX(hch): any reason we don't just look at mp->m_alloc_mxr?
> - */
> -#define XR_ALLOC_BLOCK_MAXRECS(mp, level) \
> -	(libxfs_allocbt_maxrecs((mp), (mp)->m_sb.sb_blocksize, (level) == 0) - 2)
> -
> -/*
> - * this calculates a freespace cursor for an ag.
> - * btree_curs is an in/out.  returns the number of
> - * blocks that will show up in the AGFL.
> - */
> -static int
> -calculate_freespace_cursor(xfs_mount_t *mp, xfs_agnumber_t agno,
> -			xfs_agblock_t *extents, bt_status_t *btree_curs)
> -{
> -	xfs_extlen_t		blocks_needed;		/* a running count */
> -	xfs_extlen_t		blocks_allocated_pt;	/* per tree */
> -	xfs_extlen_t		blocks_allocated_total;	/* for both trees */
> -	xfs_agblock_t		num_extents;
> -	int			i;
> -	int			extents_used;
> -	int			extra_blocks;
> -	bt_stat_level_t		*lptr;
> -	bt_stat_level_t		*p_lptr;
> -	extent_tree_node_t	*ext_ptr;
> -	int			level;
> -
> -	num_extents = *extents;
> -	extents_used = 0;
> -
> -	ASSERT(num_extents != 0);
> -
> -	lptr = &btree_curs->level[0];
> -	btree_curs->init = 1;
> +		while (resv->used < resv->len) {
> +			xfs_fsblock_t	fsb = resv->fsbno + resv->used;
> +			int		error;
>  
> -	/*
> -	 * figure out how much space we need for the leaf level
> -	 * of the tree and set up the cursor for the leaf level
> -	 * (note that the same code is duplicated further down)
> -	 */
> -	lptr->num_blocks = howmany(num_extents, XR_ALLOC_BLOCK_MAXRECS(mp, 0));
> -	lptr->num_recs_pb = num_extents / lptr->num_blocks;
> -	lptr->modulo = num_extents % lptr->num_blocks;
> -	lptr->num_recs_tot = num_extents;
> -	level = 1;
> -
> -#ifdef XR_BLD_FREE_TRACE
> -	fprintf(stderr, "%s 0 %d %d %d %d\n", __func__,
> -			lptr->num_blocks,
> -			lptr->num_recs_pb,
> -			lptr->modulo,
> -			lptr->num_recs_tot);
> -#endif
> -	/*
> -	 * if we need more levels, set them up.  # of records
> -	 * per level is the # of blocks in the level below it
> -	 */
> -	if (lptr->num_blocks > 1)  {
> -		for (; btree_curs->level[level - 1].num_blocks > 1
> -				&& level < XFS_BTREE_MAXLEVELS;
> -				level++)  {
> -			lptr = &btree_curs->level[level];
> -			p_lptr = &btree_curs->level[level - 1];
> -			lptr->num_blocks = howmany(p_lptr->num_blocks,
> -					XR_ALLOC_BLOCK_MAXRECS(mp, level));
> -			lptr->modulo = p_lptr->num_blocks
> -					% lptr->num_blocks;
> -			lptr->num_recs_pb = p_lptr->num_blocks
> -					/ lptr->num_blocks;
> -			lptr->num_recs_tot = p_lptr->num_blocks;
> -#ifdef XR_BLD_FREE_TRACE
> -			fprintf(stderr, "%s %d %d %d %d %d\n", __func__,
> -					level,
> -					lptr->num_blocks,
> -					lptr->num_recs_pb,
> -					lptr->modulo,
> -					lptr->num_recs_tot);
> -#endif
> -		}
> -	}
> -
> -	ASSERT(lptr->num_blocks == 1);
> -	btree_curs->num_levels = level;
> -
> -	/*
> -	 * ok, now we have a hypothetical cursor that
> -	 * will work for both the bno and bcnt trees.
> -	 * now figure out if using up blocks to set up the
> -	 * trees will perturb the shape of the freespace tree.
> -	 * if so, we've over-allocated.  the freespace trees
> -	 * as they will be *after* accounting for the free space
> -	 * we've used up will need fewer blocks to to represent
> -	 * than we've allocated.  We can use the AGFL to hold
> -	 * xfs_agfl_size (sector/struct xfs_agfl) blocks but that's it.
> -	 * Thus we limit things to xfs_agfl_size/2 for each of the 2 btrees.
> -	 * if the number of extra blocks is more than that,
> -	 * we'll have to be called again.
> -	 */
> -	for (blocks_needed = 0, i = 0; i < level; i++)  {
> -		blocks_needed += btree_curs->level[i].num_blocks;
> -	}
> -
> -	/*
> -	 * record the # of blocks we've allocated
> -	 */
> -	blocks_allocated_pt = blocks_needed;
> -	blocks_needed *= 2;
> -	blocks_allocated_total = blocks_needed;
> -
> -	/*
> -	 * figure out how many free extents will be used up by
> -	 * our space allocation
> -	 */
> -	if ((ext_ptr = findfirst_bcnt_extent(agno)) == NULL)
> -		do_error(_("can't rebuild fs trees -- not enough free space "
> -			   "on ag %u\n"), agno);
> -
> -	while (ext_ptr != NULL && blocks_needed > 0)  {
> -		if (ext_ptr->ex_blockcount <= blocks_needed)  {
> -			blocks_needed -= ext_ptr->ex_blockcount;
> -			extents_used++;
> -		} else  {
> -			blocks_needed = 0;
> -		}
> -
> -		ext_ptr = findnext_bcnt_extent(agno, ext_ptr);
> -
> -#ifdef XR_BLD_FREE_TRACE
> -		if (ext_ptr != NULL)  {
> -			fprintf(stderr, "got next extent [%u %u]\n",
> -				ext_ptr->ex_startblock, ext_ptr->ex_blockcount);
> -		} else  {
> -			fprintf(stderr, "out of extents\n");
> -		}
> -#endif
> -	}
> -	if (blocks_needed > 0)
> -		do_error(_("ag %u - not enough free space to build freespace "
> -			   "btrees\n"), agno);
> -
> -	ASSERT(num_extents >= extents_used);
> -
> -	num_extents -= extents_used;
> -
> -	/*
> -	 * see if the number of leaf blocks will change as a result
> -	 * of the number of extents changing
> -	 */
> -	if (howmany(num_extents, XR_ALLOC_BLOCK_MAXRECS(mp, 0))
> -			!= btree_curs->level[0].num_blocks)  {
> -		/*
> -		 * yes -- recalculate the cursor.  If the number of
> -		 * excess (overallocated) blocks is < xfs_agfl_size/2, we're ok.
> -		 * we can put those into the AGFL.  we don't try
> -		 * and get things to converge exactly (reach a
> -		 * state with zero excess blocks) because there
> -		 * exist pathological cases which will never
> -		 * converge.  first, check for the zero-case.
> -		 */
> -		if (num_extents == 0)  {
> -			/*
> -			 * ok, we've used up all the free blocks
> -			 * trying to lay out the leaf level. go
> -			 * to a one block (empty) btree and put the
> -			 * already allocated blocks into the AGFL
> -			 */
> -			if (btree_curs->level[0].num_blocks != 1)  {
> -				/*
> -				 * we really needed more blocks because
> -				 * the old tree had more than one level.
> -				 * this is bad.
> -				 */
> -				 do_warn(_("not enough free blocks left to "
> -					   "describe all free blocks in AG "
> -					   "%u\n"), agno);
> -			}
> -#ifdef XR_BLD_FREE_TRACE
> -			fprintf(stderr,
> -				"ag %u -- no free extents, alloc'ed %d\n",
> -				agno, blocks_allocated_pt);
> -#endif
> -			lptr->num_blocks = 1;
> -			lptr->modulo = 0;
> -			lptr->num_recs_pb = 0;
> -			lptr->num_recs_tot = 0;
> -
> -			btree_curs->num_levels = 1;
> -
> -			/*
> -			 * don't reset the allocation stats, assume
> -			 * they're all extra blocks
> -			 * don't forget to return the total block count
> -			 * not the per-tree block count.  these are the
> -			 * extras that will go into the AGFL.  subtract
> -			 * two for the root blocks.
> -			 */
> -			btree_curs->num_tot_blocks = blocks_allocated_pt;
> -			btree_curs->num_free_blocks = blocks_allocated_pt;
> -
> -			*extents = 0;
> -
> -			return(blocks_allocated_total - 2);
> -		}
> -
> -		lptr = &btree_curs->level[0];
> -		lptr->num_blocks = howmany(num_extents,
> -					XR_ALLOC_BLOCK_MAXRECS(mp, 0));
> -		lptr->num_recs_pb = num_extents / lptr->num_blocks;
> -		lptr->modulo = num_extents % lptr->num_blocks;
> -		lptr->num_recs_tot = num_extents;
> -		level = 1;
> -
> -		/*
> -		 * if we need more levels, set them up
> -		 */
> -		if (lptr->num_blocks > 1)  {
> -			for (level = 1; btree_curs->level[level-1].num_blocks
> -					> 1 && level < XFS_BTREE_MAXLEVELS;
> -					level++)  {
> -				lptr = &btree_curs->level[level];
> -				p_lptr = &btree_curs->level[level-1];
> -				lptr->num_blocks = howmany(p_lptr->num_blocks,
> -					XR_ALLOC_BLOCK_MAXRECS(mp, level));
> -				lptr->modulo = p_lptr->num_blocks
> -						% lptr->num_blocks;
> -				lptr->num_recs_pb = p_lptr->num_blocks
> -						/ lptr->num_blocks;
> -				lptr->num_recs_tot = p_lptr->num_blocks;
> -			}
> -		}
> -		ASSERT(lptr->num_blocks == 1);
> -		btree_curs->num_levels = level;
> -
> -		/*
> -		 * now figure out the number of excess blocks
> -		 */
> -		for (blocks_needed = 0, i = 0; i < level; i++)  {
> -			blocks_needed += btree_curs->level[i].num_blocks;
> -		}
> -		blocks_needed *= 2;
> -
> -		ASSERT(blocks_allocated_total >= blocks_needed);
> -		extra_blocks = blocks_allocated_total - blocks_needed;
> -	} else  {
> -		if (extents_used > 0) {
> -			/*
> -			 * reset the leaf level geometry to account
> -			 * for consumed extents.  we can leave the
> -			 * rest of the cursor alone since the number
> -			 * of leaf blocks hasn't changed.
> -			 */
> -			lptr = &btree_curs->level[0];
> -
> -			lptr->num_recs_pb = num_extents / lptr->num_blocks;
> -			lptr->modulo = num_extents % lptr->num_blocks;
> -			lptr->num_recs_tot = num_extents;
> +			error = slab_add(lost_fsb, &fsb);
> +			if (error)
> +				do_error(
> +_("Insufficient memory saving lost blocks.\n"));
> +			resv->used++;
>  		}
> -
> -		extra_blocks = 0;
>  	}
>  
> -	btree_curs->num_tot_blocks = blocks_allocated_pt;
> -	btree_curs->num_free_blocks = blocks_allocated_pt;
> -
> -	*extents = num_extents;
> -
> -	return(extra_blocks);
> +	xrep_newbt_destroy(&btr->newbt, 0);
>  }
>  
>  /* Map btnum to buffer ops for the types that need it. */
> @@ -838,268 +568,202 @@ btnum_to_ops(
>  	}
>  }
>  
> +/*
> + * Free Space Btrees
> + *
> + * We need to leave some free records in the tree for the corner case of
> + * setting up the AGFL. This may require allocation of blocks, and as
> + * such can require insertion of new records into the tree (e.g. moving
> + * a record in the by-count tree when a long extent is shortened). If we
> + * pack the records into the leaves with no slack space, this requires a
> + * leaf split to occur and a block to be allocated from the free list.
> + * If we don't have any blocks on the free list (because we are setting
> + * it up!), then we fail, and the filesystem will fail with the same
> + * failure at runtime. Hence leave a couple of records slack space in
> + * each block to allow immediate modification of the tree without
> + * requiring splits to be done.
> + */
> +
>  static void
> -prop_freespace_cursor(xfs_mount_t *mp, xfs_agnumber_t agno,
> -		bt_status_t *btree_curs, xfs_agblock_t startblock,
> -		xfs_extlen_t blockcount, int level, xfs_btnum_t btnum)
> +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)
>  {
> -	struct xfs_btree_block	*bt_hdr;
> -	xfs_alloc_key_t		*bt_key;
> -	xfs_alloc_ptr_t		*bt_ptr;
> -	xfs_agblock_t		agbno;
> -	bt_stat_level_t		*lptr;
> -	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);
> +	init_rebuild(sc, &XFS_RMAP_OINFO_AG, free_space, btr_bno);
> +	init_rebuild(sc, &XFS_RMAP_OINFO_AG, free_space, btr_cnt);
>  
> -	level++;
> -
> -	if (level >= btree_curs->num_levels)
> -		return;
> -
> -	lptr = &btree_curs->level[level];
> -	bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
> -
> -	if (be16_to_cpu(bt_hdr->bb_numrecs) == 0)  {
> -		/*
> -		 * only happens once when initializing the
> -		 * left-hand side of the tree.
> -		 */
> -		prop_freespace_cursor(mp, agno, btree_curs, startblock,
> -				blockcount, level, btnum);
> -	}
> +	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);
>  
> -	if (be16_to_cpu(bt_hdr->bb_numrecs) ==
> -				lptr->num_recs_pb + (lptr->modulo > 0))  {
> -		/*
> -		 * write out current prev block, grab us a new block,
> -		 * and set the rightsib pointer of current block
> -		 */
> -#ifdef XR_BLD_FREE_TRACE
> -		fprintf(stderr, " %d ", lptr->prev_agbno);
> -#endif
> -		if (lptr->prev_agbno != NULLAGBLOCK) {
> -			ASSERT(lptr->prev_buf_p != NULL);
> -			libxfs_buf_mark_dirty(lptr->prev_buf_p);
> -			libxfs_buf_relse(lptr->prev_buf_p);
> -		}
> -		lptr->prev_agbno = lptr->agbno;;
> -		lptr->prev_buf_p = lptr->buf_p;
> -		agbno = get_next_blockaddr(agno, level, btree_curs);
> +	/*
> +	 * 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.
> +	 */
> +	do {
> +		unsigned int	num_freeblocks;
>  
> -		bt_hdr->bb_u.s.bb_rightsib = cpu_to_be32(agbno);
> +		bno_blocks = btr_bno->bload.nr_blocks;
> +		cnt_blocks = btr_cnt->bload.nr_blocks;
>  
> -		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(
> -	_("Cannot grab free space btree buffer, err=%d"),
> -					error);
> -		lptr->agbno = agbno;
> +_("Unable to compute free space by block btree geometry, error %d.\n"), -error);
>  
> -		if (lptr->modulo)
> -			lptr->modulo--;
> -
> -		/*
> -		 * initialize block header
> -		 */
> -		lptr->buf_p->b_ops = ops;
> -		bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
> -		memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
> -		libxfs_btree_init_block(mp, lptr->buf_p, btnum, level,
> -					0, agno);
> +		/* Compute how many cntbt blocks we'll need. */
> +		error = -libxfs_btree_bload_compute_geometry(btr_bno->cur,
> +				&btr_cnt->bload, *nr_extents);
> +		if (error)
> +			do_error(
> +_("Unable to compute free space by length btree geometry, error %d.\n"), -error);
>  
> -		bt_hdr->bb_u.s.bb_leftsib = cpu_to_be32(lptr->prev_agbno);
> +		/* 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;
>  
> -		/*
> -		 * propagate extent record for first extent in new block up
> -		 */
> -		prop_freespace_cursor(mp, agno, btree_curs, startblock,
> -				blockcount, level, btnum);
> -	}
> -	/*
> -	 * add extent info to current block
> -	 */
> -	be16_add_cpu(&bt_hdr->bb_numrecs, 1);
> +		/* 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);
>  
> -	bt_key = XFS_ALLOC_KEY_ADDR(mp, bt_hdr,
> -				be16_to_cpu(bt_hdr->bb_numrecs));
> -	bt_ptr = XFS_ALLOC_PTR_ADDR(mp, bt_hdr,
> -				be16_to_cpu(bt_hdr->bb_numrecs),
> -				mp->m_alloc_mxr[1]);
> +		/* Ok, now how many free space records do we have? */
> +		*nr_extents = count_bno_extents_blocks(agno, &num_freeblocks);
> +	} while (1);
>  
> -	bt_key->ar_startblock = cpu_to_be32(startblock);
> -	bt_key->ar_blockcount = cpu_to_be32(blockcount);
> -	*bt_ptr = cpu_to_be32(btree_curs->level[level-1].agbno);
> +	*extra_blocks = (bno_blocks - btr_bno->bload.nr_blocks) +
> +			(cnt_blocks - btr_cnt->bload.nr_blocks);
>  }
>  
> -/*
> - * rebuilds a freespace tree given a cursor and type
> - * of tree to build (bno or bcnt).  returns the number of free blocks
> - * represented by the tree.
> - */
> -static xfs_extlen_t
> -build_freespace_tree(xfs_mount_t *mp, xfs_agnumber_t agno,
> -		bt_status_t *btree_curs, xfs_btnum_t btnum)
> +static void
> +get_freesp_data(
> +	struct xfs_btree_cur		*cur,
> +	struct extent_tree_node		*bno_rec,
> +	xfs_agblock_t			*freeblks)
>  {
> -	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);
> -	int			error;
> +	struct xfs_alloc_rec_incore	*arec = &cur->bc_rec.a;
>  
> -	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;
> +	arec->ar_startblock = bno_rec->ex_startblock;
> +	arec->ar_blockcount = bno_rec->ex_blockcount;
> +	if (freeblks)
> +		*freeblks += bno_rec->ex_blockcount;
> +}
>  
> -	ASSERT(level > 0);
> +/* Grab one bnobt record. */
> +static int
> +get_bnobt_record(
> +	struct xfs_btree_cur		*cur,
> +	void				*priv)
> +{
> +	struct bt_rebuild		*btr = priv;
>  
> -	/*
> -	 * initialize the first block on each btree level
> -	 */
> -	for (i = 0; i < level; i++)  {
> -		lptr = &btree_curs->level[i];
> +	get_freesp_data(cur, btr->bno_rec, btr->freeblks);
> +	btr->bno_rec = findnext_bno_extent(btr->bno_rec);
> +	return 0;
> +}
>  
> -		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);
> -		if (error)
> -			do_error(
> -	_("Cannot grab free space btree buffer, err=%d"),
> -					error);
> +/* 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;
>  
> -		if (i == btree_curs->num_levels - 1)
> -			btree_curs->root = agbno;
> +	*freeblks = 0;
> +	btr_bno->bload.get_record = get_bnobt_record;
> +	btr_bno->bload.claim_block = rebuild_claim_block;
> +	btr_bno->bno_rec = findfirst_bno_extent(agno);
> +	btr_bno->freeblks = freeblks;
>  
> -		lptr->agbno = agbno;
> -		lptr->prev_agbno = NULLAGBLOCK;
> -		lptr->prev_buf_p = NULL;
> -		/*
> -		 * initialize block header
> -		 */
> -		lptr->buf_p->b_ops = ops;
> -		bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
> -		memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
> -		libxfs_btree_init_block(mp, lptr->buf_p, btnum, i, 0, agno);
> -	}
> -	/*
> -	 * run along leaf, setting up records.  as we have to switch
> -	 * blocks, call the prop_freespace_cursor routine to set up the new
> -	 * pointers for the parent.  that can recurse up to the root
> -	 * if required.  set the sibling pointers for leaf level here.
> -	 */
> -	if (btnum == XFS_BTNUM_BNO)
> -		ext_ptr = findfirst_bno_extent(agno);
> -	else
> -		ext_ptr = findfirst_bcnt_extent(agno);
> +	error = -libxfs_trans_alloc_empty(sc->mp, &sc->tp);
> +	if (error)
> +		do_error(
> +_("Insufficient memory to construct bnobt rebuild transaction.\n"));
>  
> -#ifdef XR_BLD_FREE_TRACE
> -	fprintf(stderr, "bft, agno = %d, start = %u, count = %u\n",
> -		agno, ext_ptr->ex_startblock, ext_ptr->ex_blockcount);
> -#endif
> +	/* 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);
>  
> -	lptr = &btree_curs->level[0];
> +	/* 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;
> +}
>  
> -	for (i = 0; i < btree_curs->level[0].num_blocks; i++)  {
> -		/*
> -		 * block initialization, lay in block header
> -		 */
> -		lptr->buf_p->b_ops = ops;
> -		bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
> -		memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
> -		libxfs_btree_init_block(mp, lptr->buf_p, btnum, 0, 0, agno);
> +/* Grab one cntbt record. */
> +static int
> +get_cntbt_record(
> +	struct xfs_btree_cur		*cur,
> +	void				*priv)
> +{
> +	struct bt_rebuild		*btr = priv;
>  
> -		bt_hdr->bb_u.s.bb_leftsib = cpu_to_be32(lptr->prev_agbno);
> -		bt_hdr->bb_numrecs = cpu_to_be16(lptr->num_recs_pb +
> -							(lptr->modulo > 0));
> -#ifdef XR_BLD_FREE_TRACE
> -		fprintf(stderr, "bft, bb_numrecs = %d\n",
> -				be16_to_cpu(bt_hdr->bb_numrecs));
> -#endif
> +	get_freesp_data(cur, btr->bno_rec, btr->freeblks);
> +	btr->bno_rec = findnext_bcnt_extent(cur->bc_ag.agno, btr->bno_rec);
> +	return 0;
> +}
>  
> -		if (lptr->modulo > 0)
> -			lptr->modulo--;
> +/* Rebuild a freespace by count btree. */
> +static void
> +build_cntbt(
> +	struct repair_ctx	*sc,
> +	xfs_agnumber_t		agno,
> +	struct bt_rebuild	*btr_cnt,
> +	xfs_agblock_t		*freeblks)
> +{
> +	int			error;
>  
> -		/*
> -		 * initialize values in the path up to the root if
> -		 * this is a multi-level btree
> -		 */
> -		if (btree_curs->num_levels > 1)
> -			prop_freespace_cursor(mp, agno, btree_curs,
> -					ext_ptr->ex_startblock,
> -					ext_ptr->ex_blockcount,
> -					0, btnum);
> -
> -		bt_rec = (xfs_alloc_rec_t *)
> -			  ((char *)bt_hdr + XFS_ALLOC_BLOCK_LEN(mp));
> -		for (j = 0; j < be16_to_cpu(bt_hdr->bb_numrecs); j++) {
> -			ASSERT(ext_ptr != NULL);
> -			bt_rec[j].ar_startblock = cpu_to_be32(
> -							ext_ptr->ex_startblock);
> -			bt_rec[j].ar_blockcount = cpu_to_be32(
> -							ext_ptr->ex_blockcount);
> -			freeblks += ext_ptr->ex_blockcount;
> -			if (btnum == XFS_BTNUM_BNO)
> -				ext_ptr = findnext_bno_extent(ext_ptr);
> -			else
> -				ext_ptr = findnext_bcnt_extent(agno, ext_ptr);
> -#if 0
> -#ifdef XR_BLD_FREE_TRACE
> -			if (ext_ptr == NULL)
> -				fprintf(stderr, "null extent pointer, j = %d\n",
> -					j);
> -			else
> -				fprintf(stderr,
> -				"bft, agno = %d, start = %u, count = %u\n",
> -					agno, ext_ptr->ex_startblock,
> -					ext_ptr->ex_blockcount);
> -#endif
> -#endif
> -		}
> +	*freeblks = 0;
> +	btr_cnt->bload.get_record = get_cntbt_record;
> +	btr_cnt->bload.claim_block = rebuild_claim_block;
> +	btr_cnt->bno_rec = findfirst_bcnt_extent(agno);
> +	btr_cnt->freeblks = freeblks;
>  
> -		if (ext_ptr != NULL)  {
> -			/*
> -			 * get next leaf level block
> -			 */
> -			if (lptr->prev_buf_p != NULL)  {
> -#ifdef XR_BLD_FREE_TRACE
> -				fprintf(stderr, " writing fst agbno %u\n",
> -					lptr->prev_agbno);
> -#endif
> -				ASSERT(lptr->prev_agbno != NULLAGBLOCK);
> -				libxfs_buf_mark_dirty(lptr->prev_buf_p);
> -				libxfs_buf_relse(lptr->prev_buf_p);
> -			}
> -			lptr->prev_buf_p = lptr->buf_p;
> -			lptr->prev_agbno = lptr->agbno;
> -			lptr->agbno = get_next_blockaddr(agno, 0, btree_curs);
> -			bt_hdr->bb_u.s.bb_rightsib = cpu_to_be32(lptr->agbno);
> +	error = -libxfs_trans_alloc_empty(sc->mp, &sc->tp);
> +	if (error)
> +		do_error(
> +_("Insufficient memory to construct cntbt rebuild transaction.\n"));
>  
> -			error = -libxfs_buf_get(mp->m_dev,
> -					XFS_AGB_TO_DADDR(mp, agno, lptr->agbno),
> -					XFS_FSB_TO_BB(mp, 1),
> -					&lptr->buf_p);
> -			if (error)
> -				do_error(
> -	_("Cannot grab free space btree buffer, err=%d"),
> -						error);
> -		}
> -	}
> +	/* Add all observed cntbt records. */
> +	error = -libxfs_btree_bload(btr_cnt->cur, &btr_cnt->bload, btr_cnt);
> +	if (error)
> +		do_error(
> +_("Error %d while creating cntbt btree for AG %u.\n"), error, agno);
>  
> -	return(freeblks);
> +	/* Since we're not writing the AGF yet, no need to commit the cursor */
> +	libxfs_btree_del_cursor(btr_cnt->cur, 0);
> +	error = -libxfs_trans_commit(sc->tp);
> +	if (error)
> +		do_error(
> +_("Error %d while writing cntbt btree for AG %u.\n"), error, agno);
> +	sc->tp = NULL;
>  }
>  
>  /*
> @@ -2233,6 +1897,27 @@ _("Insufficient memory to construct refcount cursor."));
>  	free_slab_cursor(&refc_cur);
>  }
>  
> +/* Fill the AGFL with any leftover bnobt rebuilder blocks. */
> +static void
> +fill_agfl(
> +	struct bt_rebuild	*btr,
> +	__be32			*agfl_bnos,
> +	int			*i)
> +{
> +	struct xrep_newbt_resv	*resv, *n;
> +	struct xfs_mount	*mp = btr->newbt.sc->mp;
> +
> +	for_each_xrep_newbt_reservation(&btr->newbt, resv, n) {
> +		xfs_agblock_t	bno;
> +
> +		bno = XFS_FSB_TO_AGBNO(mp, resv->fsbno + resv->used);
> +		while (resv->used < resv->len && (*i) < libxfs_agfl_size(mp)) {
> +			agfl_bnos[(*i)++] = cpu_to_be32(bno++);
> +			resv->used++;
> +		}
> +	}
> +}
> +
>  /*
>   * build both the agf and the agfl for an agno given both
>   * btree cursors.
> @@ -2243,8 +1928,8 @@ static void
>  build_agf_agfl(
>  	struct xfs_mount	*mp,
>  	xfs_agnumber_t		agno,
> -	struct bt_status	*bno_bt,
> -	struct bt_status	*bcnt_bt,
> +	struct bt_rebuild	*btr_bno,
> +	struct bt_rebuild	*btr_cnt,
>  	xfs_extlen_t		freeblks,	/* # free blocks in tree */
>  	int			lostblocks,	/* # blocks that will be lost */
>  	struct bt_status	*rmap_bt,
> @@ -2256,7 +1941,6 @@ build_agf_agfl(
>  	int			i;
>  	struct xfs_agfl		*agfl;
>  	struct xfs_agf		*agf;
> -	xfs_fsblock_t		fsb;
>  	__be32			*freelist;
>  	int			error;
>  
> @@ -2288,10 +1972,14 @@ build_agf_agfl(
>  		agf->agf_length = cpu_to_be32(mp->m_sb.sb_dblocks -
>  			(xfs_rfsblock_t) mp->m_sb.sb_agblocks * agno);
>  
> -	agf->agf_roots[XFS_BTNUM_BNO] = cpu_to_be32(bno_bt->root);
> -	agf->agf_levels[XFS_BTNUM_BNO] = cpu_to_be32(bno_bt->num_levels);
> -	agf->agf_roots[XFS_BTNUM_CNT] = cpu_to_be32(bcnt_bt->root);
> -	agf->agf_levels[XFS_BTNUM_CNT] = cpu_to_be32(bcnt_bt->num_levels);
> +	agf->agf_roots[XFS_BTNUM_BNO] =
> +			cpu_to_be32(btr_bno->newbt.afake.af_root);
> +	agf->agf_levels[XFS_BTNUM_BNO] =
> +			cpu_to_be32(btr_bno->newbt.afake.af_levels);
> +	agf->agf_roots[XFS_BTNUM_CNT] =
> +			cpu_to_be32(btr_cnt->newbt.afake.af_root);
> +	agf->agf_levels[XFS_BTNUM_CNT] =
> +			cpu_to_be32(btr_cnt->newbt.afake.af_levels);
>  	agf->agf_roots[XFS_BTNUM_RMAP] = cpu_to_be32(rmap_bt->root);
>  	agf->agf_levels[XFS_BTNUM_RMAP] = cpu_to_be32(rmap_bt->num_levels);
>  	agf->agf_freeblks = cpu_to_be32(freeblks);
> @@ -2311,9 +1999,8 @@ build_agf_agfl(
>  		 * Don't count the root blocks as they are already
>  		 * accounted for.
>  		 */
> -		blks = (bno_bt->num_tot_blocks - bno_bt->num_free_blocks) +
> -			(bcnt_bt->num_tot_blocks - bcnt_bt->num_free_blocks) -
> -			2;
> +		blks = btr_bno->newbt.afake.af_blocks +
> +			btr_cnt->newbt.afake.af_blocks - 2;
>  		if (xfs_sb_version_hasrmapbt(&mp->m_sb))
>  			blks += rmap_bt->num_tot_blocks - rmap_bt->num_free_blocks - 1;
>  		agf->agf_btreeblks = cpu_to_be32(blks);
> @@ -2357,49 +2044,14 @@ build_agf_agfl(
>  	}
>  
>  	freelist = xfs_buf_to_agfl_bno(agfl_buf);
> +	i = 0;
>  
> -	/*
> -	 * 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. */
> +	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);
> @@ -2497,8 +2149,8 @@ phase5_func(
>  	uint64_t		num_free_inos;
>  	uint64_t		finobt_num_inos;
>  	uint64_t		finobt_num_free_inos;
> -	bt_status_t		bno_btree_curs;
> -	bt_status_t		bcnt_btree_curs;
> +	struct bt_rebuild	btr_bno;
> +	struct bt_rebuild	btr_cnt;
>  	bt_status_t		ino_btree_curs;
>  	bt_status_t		fino_btree_curs;
>  	bt_status_t		rmap_btree_curs;
> @@ -2506,9 +2158,7 @@ phase5_func(
>  	int			extra_blocks = 0;
>  	uint			num_freeblocks;
>  	xfs_extlen_t		freeblks1;
> -#ifdef DEBUG
>  	xfs_extlen_t		freeblks2;
> -#endif
>  	xfs_agblock_t		num_extents;
>  
>  	if (verbose)
> @@ -2517,7 +2167,7 @@ phase5_func(
>  	/*
>  	 * build up incore bno and bcnt extent btrees
>  	 */
> -	num_extents = mk_incore_fstree(mp, agno);
> +	num_extents = mk_incore_fstree(mp, agno, &num_freeblocks);
>  
>  #ifdef XR_BLD_FREE_TRACE
>  	fprintf(stderr, "# of bno extents is %d\n",
> @@ -2596,8 +2246,8 @@ phase5_func(
>  	/*
>  	 * track blocks that we might really lose
>  	 */
> -	extra_blocks = calculate_freespace_cursor(mp, agno,
> -				&num_extents, &bno_btree_curs);
> +	init_freespace_cursors(&sc, agno, num_freeblocks, &num_extents,
> +			&extra_blocks, &btr_bno, &btr_cnt);
>  
>  	/*
>  	 * freespace btrees live in the "free space" but
> @@ -2615,13 +2265,6 @@ phase5_func(
>  	if (extra_blocks > 0)
>  		sb_fdblocks_ag[agno] -= extra_blocks;
>  
> -	bcnt_btree_curs = bno_btree_curs;
> -
> -	bno_btree_curs.owner = XFS_RMAP_OWN_AG;
> -	bcnt_btree_curs.owner = XFS_RMAP_OWN_AG;
> -	setup_cursor(mp, agno, &bno_btree_curs);
> -	setup_cursor(mp, agno, &bcnt_btree_curs);
> -
>  #ifdef XR_BLD_FREE_TRACE
>  	fprintf(stderr, "# of bno extents is %d\n",
>  			count_bno_extents(agno));
> @@ -2629,25 +2272,13 @@ phase5_func(
>  			count_bcnt_extents(agno));
>  #endif
>  
> -	/*
> -	 * now rebuild the freespace trees
> -	 */
> -	freeblks1 = build_freespace_tree(mp, agno,
> -				&bno_btree_curs, XFS_BTNUM_BNO);
> +	/* Rebuild the freespace btrees. */
> +	build_bnobt(&sc, agno, &btr_bno, &freeblks1);
> +	build_cntbt(&sc, agno, &btr_cnt, &freeblks2);
> +
>  #ifdef XR_BLD_FREE_TRACE
> -	fprintf(stderr, "# of free blocks == %d\n", freeblks1);
> -#endif
> -	write_cursor(&bno_btree_curs);
> -
> -#ifdef DEBUG
> -	freeblks2 = build_freespace_tree(mp, agno,
> -				&bcnt_btree_curs, XFS_BTNUM_CNT);
> -#else
> -	(void) build_freespace_tree(mp, agno,
> -				&bcnt_btree_curs, XFS_BTNUM_CNT);
> +	fprintf(stderr, "# of free blocks == %d/%d\n", freeblks1, freeblks2);
>  #endif
> -	write_cursor(&bcnt_btree_curs);
> -
>  	ASSERT(freeblks1 == freeblks2);
>  
>  	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
> @@ -2665,9 +2296,9 @@ phase5_func(
>  	/*
>  	 * set up agf and agfl
>  	 */
> -	build_agf_agfl(mp, agno, &bno_btree_curs,
> -			&bcnt_btree_curs, freeblks1, extra_blocks,
> +	build_agf_agfl(mp, agno, &btr_bno, &btr_cnt, freeblks1, extra_blocks,
>  			&rmap_btree_curs, &refcnt_btree_curs, lost_fsb);
> +
>  	/*
>  	 * build inode allocation tree.
>  	 */
> @@ -2691,15 +2322,14 @@ phase5_func(
>  	/*
>  	 * tear down cursors
>  	 */
> -	finish_cursor(&bno_btree_curs);
> -	finish_cursor(&ino_btree_curs);
> +	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
>
Darrick J. Wong May 14, 2020, 7:53 p.m. UTC | #2
On Thu, May 14, 2020 at 11:12:05AM -0400, Brian Foster wrote:
> On Sat, May 09, 2020 at 09:32:08AM -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          |  858 +++++++++++++---------------------------------
> >  2 files changed, 247 insertions(+), 614 deletions(-)
> > 
> > 
> ...
> > diff --git a/repair/phase5.c b/repair/phase5.c
> > index 7eb24519..94e4610c 100644
> > --- a/repair/phase5.c
> > +++ b/repair/phase5.c
> ...
> > @@ -465,7 +476,7 @@ _("error - not enough free space in filesystem\n"));
> >  
> >  /* Feed one of the new btree blocks to the bulk loader. */
> >  static int
> > -rebuild_alloc_block(
> > +rebuild_claim_block(
> >  	struct xfs_btree_cur	*cur,
> >  	union xfs_btree_ptr	*ptr,
> >  	void			*priv)
> 
> Hmm.. seems like a decent amount of churn here. The above function is
> renamed and finish_rebuild() looks like it's gutted/replaced before
> either is ever used. Can we get the core bits settled into the previous
> patch(es) so they aren't changing when used to implement the tree
> reconstructions?

I bet I committed all this churn to the wrong patch back when you and I
were reviewing the similar patches for online repair.  Sorry I totally
missed this, will fix for the next resend.

(TBH I /really/ hate how diff tries to make the actual bnobt/cntbt
rebuilder changes "comparable".  They're not, and it just makes
reading this a nightmare.  Have kinda wondered if the new code should
just go somewhere else so that phase5.c can shrink a bit...)

--D

> Brian
> 
> > @@ -505,313 +516,32 @@ finish_cursor(bt_status_t *curs)
> >  	free(curs->btree_blocks);
> >  }
> >  
> > +/*
> > + * Scoop up leftovers from a rebuild cursor for later freeing, then free the
> > + * rebuild context.
> > + */
> >  static void
> >  finish_rebuild(
> >  	struct xfs_mount	*mp,
> > -	struct bt_rebuild	*btr)
> > +	struct bt_rebuild	*btr,
> > +	struct xfs_slab		*lost_fsb)
> >  {
> >  	struct xrep_newbt_resv	*resv, *n;
> >  
> >  	for_each_xrep_newbt_reservation(&btr->newbt, resv, n) {
> > -		xfs_agnumber_t	agno;
> > -		xfs_agblock_t	bno;
> > -		xfs_extlen_t	len;
> > -
> > -		if (resv->used >= resv->len)
> > -			continue;
> > -
> > -		/* XXX: Shouldn't this go on the AGFL? */
> > -		/* Put back everything we didn't use. */
> > -		bno = XFS_FSB_TO_AGBNO(mp, resv->fsbno + resv->used);
> > -		agno = XFS_FSB_TO_AGNO(mp, resv->fsbno + resv->used);
> > -		len = resv->len - resv->used;
> > -
> > -		add_bno_extent(agno, bno, len);
> > -		add_bcnt_extent(agno, bno, len);
> > -	}
> > -
> > -	xrep_newbt_destroy(&btr->newbt, 0);
> > -}
> > -
> > -/*
> > - * We need to leave some free records in the tree for the corner case of
> > - * setting up the AGFL. This may require allocation of blocks, and as
> > - * such can require insertion of new records into the tree (e.g. moving
> > - * a record in the by-count tree when a long extent is shortened). If we
> > - * pack the records into the leaves with no slack space, this requires a
> > - * leaf split to occur and a block to be allocated from the free list.
> > - * If we don't have any blocks on the free list (because we are setting
> > - * it up!), then we fail, and the filesystem will fail with the same
> > - * failure at runtime. Hence leave a couple of records slack space in
> > - * each block to allow immediate modification of the tree without
> > - * requiring splits to be done.
> > - *
> > - * XXX(hch): any reason we don't just look at mp->m_alloc_mxr?
> > - */
> > -#define XR_ALLOC_BLOCK_MAXRECS(mp, level) \
> > -	(libxfs_allocbt_maxrecs((mp), (mp)->m_sb.sb_blocksize, (level) == 0) - 2)
> > -
> > -/*
> > - * this calculates a freespace cursor for an ag.
> > - * btree_curs is an in/out.  returns the number of
> > - * blocks that will show up in the AGFL.
> > - */
> > -static int
> > -calculate_freespace_cursor(xfs_mount_t *mp, xfs_agnumber_t agno,
> > -			xfs_agblock_t *extents, bt_status_t *btree_curs)
> > -{
> > -	xfs_extlen_t		blocks_needed;		/* a running count */
> > -	xfs_extlen_t		blocks_allocated_pt;	/* per tree */
> > -	xfs_extlen_t		blocks_allocated_total;	/* for both trees */
> > -	xfs_agblock_t		num_extents;
> > -	int			i;
> > -	int			extents_used;
> > -	int			extra_blocks;
> > -	bt_stat_level_t		*lptr;
> > -	bt_stat_level_t		*p_lptr;
> > -	extent_tree_node_t	*ext_ptr;
> > -	int			level;
> > -
> > -	num_extents = *extents;
> > -	extents_used = 0;
> > -
> > -	ASSERT(num_extents != 0);
> > -
> > -	lptr = &btree_curs->level[0];
> > -	btree_curs->init = 1;
> > +		while (resv->used < resv->len) {
> > +			xfs_fsblock_t	fsb = resv->fsbno + resv->used;
> > +			int		error;
> >  
> > -	/*
> > -	 * figure out how much space we need for the leaf level
> > -	 * of the tree and set up the cursor for the leaf level
> > -	 * (note that the same code is duplicated further down)
> > -	 */
> > -	lptr->num_blocks = howmany(num_extents, XR_ALLOC_BLOCK_MAXRECS(mp, 0));
> > -	lptr->num_recs_pb = num_extents / lptr->num_blocks;
> > -	lptr->modulo = num_extents % lptr->num_blocks;
> > -	lptr->num_recs_tot = num_extents;
> > -	level = 1;
> > -
> > -#ifdef XR_BLD_FREE_TRACE
> > -	fprintf(stderr, "%s 0 %d %d %d %d\n", __func__,
> > -			lptr->num_blocks,
> > -			lptr->num_recs_pb,
> > -			lptr->modulo,
> > -			lptr->num_recs_tot);
> > -#endif
> > -	/*
> > -	 * if we need more levels, set them up.  # of records
> > -	 * per level is the # of blocks in the level below it
> > -	 */
> > -	if (lptr->num_blocks > 1)  {
> > -		for (; btree_curs->level[level - 1].num_blocks > 1
> > -				&& level < XFS_BTREE_MAXLEVELS;
> > -				level++)  {
> > -			lptr = &btree_curs->level[level];
> > -			p_lptr = &btree_curs->level[level - 1];
> > -			lptr->num_blocks = howmany(p_lptr->num_blocks,
> > -					XR_ALLOC_BLOCK_MAXRECS(mp, level));
> > -			lptr->modulo = p_lptr->num_blocks
> > -					% lptr->num_blocks;
> > -			lptr->num_recs_pb = p_lptr->num_blocks
> > -					/ lptr->num_blocks;
> > -			lptr->num_recs_tot = p_lptr->num_blocks;
> > -#ifdef XR_BLD_FREE_TRACE
> > -			fprintf(stderr, "%s %d %d %d %d %d\n", __func__,
> > -					level,
> > -					lptr->num_blocks,
> > -					lptr->num_recs_pb,
> > -					lptr->modulo,
> > -					lptr->num_recs_tot);
> > -#endif
> > -		}
> > -	}
> > -
> > -	ASSERT(lptr->num_blocks == 1);
> > -	btree_curs->num_levels = level;
> > -
> > -	/*
> > -	 * ok, now we have a hypothetical cursor that
> > -	 * will work for both the bno and bcnt trees.
> > -	 * now figure out if using up blocks to set up the
> > -	 * trees will perturb the shape of the freespace tree.
> > -	 * if so, we've over-allocated.  the freespace trees
> > -	 * as they will be *after* accounting for the free space
> > -	 * we've used up will need fewer blocks to to represent
> > -	 * than we've allocated.  We can use the AGFL to hold
> > -	 * xfs_agfl_size (sector/struct xfs_agfl) blocks but that's it.
> > -	 * Thus we limit things to xfs_agfl_size/2 for each of the 2 btrees.
> > -	 * if the number of extra blocks is more than that,
> > -	 * we'll have to be called again.
> > -	 */
> > -	for (blocks_needed = 0, i = 0; i < level; i++)  {
> > -		blocks_needed += btree_curs->level[i].num_blocks;
> > -	}
> > -
> > -	/*
> > -	 * record the # of blocks we've allocated
> > -	 */
> > -	blocks_allocated_pt = blocks_needed;
> > -	blocks_needed *= 2;
> > -	blocks_allocated_total = blocks_needed;
> > -
> > -	/*
> > -	 * figure out how many free extents will be used up by
> > -	 * our space allocation
> > -	 */
> > -	if ((ext_ptr = findfirst_bcnt_extent(agno)) == NULL)
> > -		do_error(_("can't rebuild fs trees -- not enough free space "
> > -			   "on ag %u\n"), agno);
> > -
> > -	while (ext_ptr != NULL && blocks_needed > 0)  {
> > -		if (ext_ptr->ex_blockcount <= blocks_needed)  {
> > -			blocks_needed -= ext_ptr->ex_blockcount;
> > -			extents_used++;
> > -		} else  {
> > -			blocks_needed = 0;
> > -		}
> > -
> > -		ext_ptr = findnext_bcnt_extent(agno, ext_ptr);
> > -
> > -#ifdef XR_BLD_FREE_TRACE
> > -		if (ext_ptr != NULL)  {
> > -			fprintf(stderr, "got next extent [%u %u]\n",
> > -				ext_ptr->ex_startblock, ext_ptr->ex_blockcount);
> > -		} else  {
> > -			fprintf(stderr, "out of extents\n");
> > -		}
> > -#endif
> > -	}
> > -	if (blocks_needed > 0)
> > -		do_error(_("ag %u - not enough free space to build freespace "
> > -			   "btrees\n"), agno);
> > -
> > -	ASSERT(num_extents >= extents_used);
> > -
> > -	num_extents -= extents_used;
> > -
> > -	/*
> > -	 * see if the number of leaf blocks will change as a result
> > -	 * of the number of extents changing
> > -	 */
> > -	if (howmany(num_extents, XR_ALLOC_BLOCK_MAXRECS(mp, 0))
> > -			!= btree_curs->level[0].num_blocks)  {
> > -		/*
> > -		 * yes -- recalculate the cursor.  If the number of
> > -		 * excess (overallocated) blocks is < xfs_agfl_size/2, we're ok.
> > -		 * we can put those into the AGFL.  we don't try
> > -		 * and get things to converge exactly (reach a
> > -		 * state with zero excess blocks) because there
> > -		 * exist pathological cases which will never
> > -		 * converge.  first, check for the zero-case.
> > -		 */
> > -		if (num_extents == 0)  {
> > -			/*
> > -			 * ok, we've used up all the free blocks
> > -			 * trying to lay out the leaf level. go
> > -			 * to a one block (empty) btree and put the
> > -			 * already allocated blocks into the AGFL
> > -			 */
> > -			if (btree_curs->level[0].num_blocks != 1)  {
> > -				/*
> > -				 * we really needed more blocks because
> > -				 * the old tree had more than one level.
> > -				 * this is bad.
> > -				 */
> > -				 do_warn(_("not enough free blocks left to "
> > -					   "describe all free blocks in AG "
> > -					   "%u\n"), agno);
> > -			}
> > -#ifdef XR_BLD_FREE_TRACE
> > -			fprintf(stderr,
> > -				"ag %u -- no free extents, alloc'ed %d\n",
> > -				agno, blocks_allocated_pt);
> > -#endif
> > -			lptr->num_blocks = 1;
> > -			lptr->modulo = 0;
> > -			lptr->num_recs_pb = 0;
> > -			lptr->num_recs_tot = 0;
> > -
> > -			btree_curs->num_levels = 1;
> > -
> > -			/*
> > -			 * don't reset the allocation stats, assume
> > -			 * they're all extra blocks
> > -			 * don't forget to return the total block count
> > -			 * not the per-tree block count.  these are the
> > -			 * extras that will go into the AGFL.  subtract
> > -			 * two for the root blocks.
> > -			 */
> > -			btree_curs->num_tot_blocks = blocks_allocated_pt;
> > -			btree_curs->num_free_blocks = blocks_allocated_pt;
> > -
> > -			*extents = 0;
> > -
> > -			return(blocks_allocated_total - 2);
> > -		}
> > -
> > -		lptr = &btree_curs->level[0];
> > -		lptr->num_blocks = howmany(num_extents,
> > -					XR_ALLOC_BLOCK_MAXRECS(mp, 0));
> > -		lptr->num_recs_pb = num_extents / lptr->num_blocks;
> > -		lptr->modulo = num_extents % lptr->num_blocks;
> > -		lptr->num_recs_tot = num_extents;
> > -		level = 1;
> > -
> > -		/*
> > -		 * if we need more levels, set them up
> > -		 */
> > -		if (lptr->num_blocks > 1)  {
> > -			for (level = 1; btree_curs->level[level-1].num_blocks
> > -					> 1 && level < XFS_BTREE_MAXLEVELS;
> > -					level++)  {
> > -				lptr = &btree_curs->level[level];
> > -				p_lptr = &btree_curs->level[level-1];
> > -				lptr->num_blocks = howmany(p_lptr->num_blocks,
> > -					XR_ALLOC_BLOCK_MAXRECS(mp, level));
> > -				lptr->modulo = p_lptr->num_blocks
> > -						% lptr->num_blocks;
> > -				lptr->num_recs_pb = p_lptr->num_blocks
> > -						/ lptr->num_blocks;
> > -				lptr->num_recs_tot = p_lptr->num_blocks;
> > -			}
> > -		}
> > -		ASSERT(lptr->num_blocks == 1);
> > -		btree_curs->num_levels = level;
> > -
> > -		/*
> > -		 * now figure out the number of excess blocks
> > -		 */
> > -		for (blocks_needed = 0, i = 0; i < level; i++)  {
> > -			blocks_needed += btree_curs->level[i].num_blocks;
> > -		}
> > -		blocks_needed *= 2;
> > -
> > -		ASSERT(blocks_allocated_total >= blocks_needed);
> > -		extra_blocks = blocks_allocated_total - blocks_needed;
> > -	} else  {
> > -		if (extents_used > 0) {
> > -			/*
> > -			 * reset the leaf level geometry to account
> > -			 * for consumed extents.  we can leave the
> > -			 * rest of the cursor alone since the number
> > -			 * of leaf blocks hasn't changed.
> > -			 */
> > -			lptr = &btree_curs->level[0];
> > -
> > -			lptr->num_recs_pb = num_extents / lptr->num_blocks;
> > -			lptr->modulo = num_extents % lptr->num_blocks;
> > -			lptr->num_recs_tot = num_extents;
> > +			error = slab_add(lost_fsb, &fsb);
> > +			if (error)
> > +				do_error(
> > +_("Insufficient memory saving lost blocks.\n"));
> > +			resv->used++;
> >  		}
> > -
> > -		extra_blocks = 0;
> >  	}
> >  
> > -	btree_curs->num_tot_blocks = blocks_allocated_pt;
> > -	btree_curs->num_free_blocks = blocks_allocated_pt;
> > -
> > -	*extents = num_extents;
> > -
> > -	return(extra_blocks);
> > +	xrep_newbt_destroy(&btr->newbt, 0);
> >  }
> >  
> >  /* Map btnum to buffer ops for the types that need it. */
> > @@ -838,268 +568,202 @@ btnum_to_ops(
> >  	}
> >  }
> >  
> > +/*
> > + * Free Space Btrees
> > + *
> > + * We need to leave some free records in the tree for the corner case of
> > + * setting up the AGFL. This may require allocation of blocks, and as
> > + * such can require insertion of new records into the tree (e.g. moving
> > + * a record in the by-count tree when a long extent is shortened). If we
> > + * pack the records into the leaves with no slack space, this requires a
> > + * leaf split to occur and a block to be allocated from the free list.
> > + * If we don't have any blocks on the free list (because we are setting
> > + * it up!), then we fail, and the filesystem will fail with the same
> > + * failure at runtime. Hence leave a couple of records slack space in
> > + * each block to allow immediate modification of the tree without
> > + * requiring splits to be done.
> > + */
> > +
> >  static void
> > -prop_freespace_cursor(xfs_mount_t *mp, xfs_agnumber_t agno,
> > -		bt_status_t *btree_curs, xfs_agblock_t startblock,
> > -		xfs_extlen_t blockcount, int level, xfs_btnum_t btnum)
> > +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)
> >  {
> > -	struct xfs_btree_block	*bt_hdr;
> > -	xfs_alloc_key_t		*bt_key;
> > -	xfs_alloc_ptr_t		*bt_ptr;
> > -	xfs_agblock_t		agbno;
> > -	bt_stat_level_t		*lptr;
> > -	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);
> > +	init_rebuild(sc, &XFS_RMAP_OINFO_AG, free_space, btr_bno);
> > +	init_rebuild(sc, &XFS_RMAP_OINFO_AG, free_space, btr_cnt);
> >  
> > -	level++;
> > -
> > -	if (level >= btree_curs->num_levels)
> > -		return;
> > -
> > -	lptr = &btree_curs->level[level];
> > -	bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
> > -
> > -	if (be16_to_cpu(bt_hdr->bb_numrecs) == 0)  {
> > -		/*
> > -		 * only happens once when initializing the
> > -		 * left-hand side of the tree.
> > -		 */
> > -		prop_freespace_cursor(mp, agno, btree_curs, startblock,
> > -				blockcount, level, btnum);
> > -	}
> > +	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);
> >  
> > -	if (be16_to_cpu(bt_hdr->bb_numrecs) ==
> > -				lptr->num_recs_pb + (lptr->modulo > 0))  {
> > -		/*
> > -		 * write out current prev block, grab us a new block,
> > -		 * and set the rightsib pointer of current block
> > -		 */
> > -#ifdef XR_BLD_FREE_TRACE
> > -		fprintf(stderr, " %d ", lptr->prev_agbno);
> > -#endif
> > -		if (lptr->prev_agbno != NULLAGBLOCK) {
> > -			ASSERT(lptr->prev_buf_p != NULL);
> > -			libxfs_buf_mark_dirty(lptr->prev_buf_p);
> > -			libxfs_buf_relse(lptr->prev_buf_p);
> > -		}
> > -		lptr->prev_agbno = lptr->agbno;;
> > -		lptr->prev_buf_p = lptr->buf_p;
> > -		agbno = get_next_blockaddr(agno, level, btree_curs);
> > +	/*
> > +	 * 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.
> > +	 */
> > +	do {
> > +		unsigned int	num_freeblocks;
> >  
> > -		bt_hdr->bb_u.s.bb_rightsib = cpu_to_be32(agbno);
> > +		bno_blocks = btr_bno->bload.nr_blocks;
> > +		cnt_blocks = btr_cnt->bload.nr_blocks;
> >  
> > -		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(
> > -	_("Cannot grab free space btree buffer, err=%d"),
> > -					error);
> > -		lptr->agbno = agbno;
> > +_("Unable to compute free space by block btree geometry, error %d.\n"), -error);
> >  
> > -		if (lptr->modulo)
> > -			lptr->modulo--;
> > -
> > -		/*
> > -		 * initialize block header
> > -		 */
> > -		lptr->buf_p->b_ops = ops;
> > -		bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
> > -		memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
> > -		libxfs_btree_init_block(mp, lptr->buf_p, btnum, level,
> > -					0, agno);
> > +		/* Compute how many cntbt blocks we'll need. */
> > +		error = -libxfs_btree_bload_compute_geometry(btr_bno->cur,
> > +				&btr_cnt->bload, *nr_extents);
> > +		if (error)
> > +			do_error(
> > +_("Unable to compute free space by length btree geometry, error %d.\n"), -error);
> >  
> > -		bt_hdr->bb_u.s.bb_leftsib = cpu_to_be32(lptr->prev_agbno);
> > +		/* 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;
> >  
> > -		/*
> > -		 * propagate extent record for first extent in new block up
> > -		 */
> > -		prop_freespace_cursor(mp, agno, btree_curs, startblock,
> > -				blockcount, level, btnum);
> > -	}
> > -	/*
> > -	 * add extent info to current block
> > -	 */
> > -	be16_add_cpu(&bt_hdr->bb_numrecs, 1);
> > +		/* 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);
> >  
> > -	bt_key = XFS_ALLOC_KEY_ADDR(mp, bt_hdr,
> > -				be16_to_cpu(bt_hdr->bb_numrecs));
> > -	bt_ptr = XFS_ALLOC_PTR_ADDR(mp, bt_hdr,
> > -				be16_to_cpu(bt_hdr->bb_numrecs),
> > -				mp->m_alloc_mxr[1]);
> > +		/* Ok, now how many free space records do we have? */
> > +		*nr_extents = count_bno_extents_blocks(agno, &num_freeblocks);
> > +	} while (1);
> >  
> > -	bt_key->ar_startblock = cpu_to_be32(startblock);
> > -	bt_key->ar_blockcount = cpu_to_be32(blockcount);
> > -	*bt_ptr = cpu_to_be32(btree_curs->level[level-1].agbno);
> > +	*extra_blocks = (bno_blocks - btr_bno->bload.nr_blocks) +
> > +			(cnt_blocks - btr_cnt->bload.nr_blocks);
> >  }
> >  
> > -/*
> > - * rebuilds a freespace tree given a cursor and type
> > - * of tree to build (bno or bcnt).  returns the number of free blocks
> > - * represented by the tree.
> > - */
> > -static xfs_extlen_t
> > -build_freespace_tree(xfs_mount_t *mp, xfs_agnumber_t agno,
> > -		bt_status_t *btree_curs, xfs_btnum_t btnum)
> > +static void
> > +get_freesp_data(
> > +	struct xfs_btree_cur		*cur,
> > +	struct extent_tree_node		*bno_rec,
> > +	xfs_agblock_t			*freeblks)
> >  {
> > -	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);
> > -	int			error;
> > +	struct xfs_alloc_rec_incore	*arec = &cur->bc_rec.a;
> >  
> > -	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;
> > +	arec->ar_startblock = bno_rec->ex_startblock;
> > +	arec->ar_blockcount = bno_rec->ex_blockcount;
> > +	if (freeblks)
> > +		*freeblks += bno_rec->ex_blockcount;
> > +}
> >  
> > -	ASSERT(level > 0);
> > +/* Grab one bnobt record. */
> > +static int
> > +get_bnobt_record(
> > +	struct xfs_btree_cur		*cur,
> > +	void				*priv)
> > +{
> > +	struct bt_rebuild		*btr = priv;
> >  
> > -	/*
> > -	 * initialize the first block on each btree level
> > -	 */
> > -	for (i = 0; i < level; i++)  {
> > -		lptr = &btree_curs->level[i];
> > +	get_freesp_data(cur, btr->bno_rec, btr->freeblks);
> > +	btr->bno_rec = findnext_bno_extent(btr->bno_rec);
> > +	return 0;
> > +}
> >  
> > -		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);
> > -		if (error)
> > -			do_error(
> > -	_("Cannot grab free space btree buffer, err=%d"),
> > -					error);
> > +/* 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;
> >  
> > -		if (i == btree_curs->num_levels - 1)
> > -			btree_curs->root = agbno;
> > +	*freeblks = 0;
> > +	btr_bno->bload.get_record = get_bnobt_record;
> > +	btr_bno->bload.claim_block = rebuild_claim_block;
> > +	btr_bno->bno_rec = findfirst_bno_extent(agno);
> > +	btr_bno->freeblks = freeblks;
> >  
> > -		lptr->agbno = agbno;
> > -		lptr->prev_agbno = NULLAGBLOCK;
> > -		lptr->prev_buf_p = NULL;
> > -		/*
> > -		 * initialize block header
> > -		 */
> > -		lptr->buf_p->b_ops = ops;
> > -		bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
> > -		memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
> > -		libxfs_btree_init_block(mp, lptr->buf_p, btnum, i, 0, agno);
> > -	}
> > -	/*
> > -	 * run along leaf, setting up records.  as we have to switch
> > -	 * blocks, call the prop_freespace_cursor routine to set up the new
> > -	 * pointers for the parent.  that can recurse up to the root
> > -	 * if required.  set the sibling pointers for leaf level here.
> > -	 */
> > -	if (btnum == XFS_BTNUM_BNO)
> > -		ext_ptr = findfirst_bno_extent(agno);
> > -	else
> > -		ext_ptr = findfirst_bcnt_extent(agno);
> > +	error = -libxfs_trans_alloc_empty(sc->mp, &sc->tp);
> > +	if (error)
> > +		do_error(
> > +_("Insufficient memory to construct bnobt rebuild transaction.\n"));
> >  
> > -#ifdef XR_BLD_FREE_TRACE
> > -	fprintf(stderr, "bft, agno = %d, start = %u, count = %u\n",
> > -		agno, ext_ptr->ex_startblock, ext_ptr->ex_blockcount);
> > -#endif
> > +	/* 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);
> >  
> > -	lptr = &btree_curs->level[0];
> > +	/* 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;
> > +}
> >  
> > -	for (i = 0; i < btree_curs->level[0].num_blocks; i++)  {
> > -		/*
> > -		 * block initialization, lay in block header
> > -		 */
> > -		lptr->buf_p->b_ops = ops;
> > -		bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
> > -		memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
> > -		libxfs_btree_init_block(mp, lptr->buf_p, btnum, 0, 0, agno);
> > +/* Grab one cntbt record. */
> > +static int
> > +get_cntbt_record(
> > +	struct xfs_btree_cur		*cur,
> > +	void				*priv)
> > +{
> > +	struct bt_rebuild		*btr = priv;
> >  
> > -		bt_hdr->bb_u.s.bb_leftsib = cpu_to_be32(lptr->prev_agbno);
> > -		bt_hdr->bb_numrecs = cpu_to_be16(lptr->num_recs_pb +
> > -							(lptr->modulo > 0));
> > -#ifdef XR_BLD_FREE_TRACE
> > -		fprintf(stderr, "bft, bb_numrecs = %d\n",
> > -				be16_to_cpu(bt_hdr->bb_numrecs));
> > -#endif
> > +	get_freesp_data(cur, btr->bno_rec, btr->freeblks);
> > +	btr->bno_rec = findnext_bcnt_extent(cur->bc_ag.agno, btr->bno_rec);
> > +	return 0;
> > +}
> >  
> > -		if (lptr->modulo > 0)
> > -			lptr->modulo--;
> > +/* Rebuild a freespace by count btree. */
> > +static void
> > +build_cntbt(
> > +	struct repair_ctx	*sc,
> > +	xfs_agnumber_t		agno,
> > +	struct bt_rebuild	*btr_cnt,
> > +	xfs_agblock_t		*freeblks)
> > +{
> > +	int			error;
> >  
> > -		/*
> > -		 * initialize values in the path up to the root if
> > -		 * this is a multi-level btree
> > -		 */
> > -		if (btree_curs->num_levels > 1)
> > -			prop_freespace_cursor(mp, agno, btree_curs,
> > -					ext_ptr->ex_startblock,
> > -					ext_ptr->ex_blockcount,
> > -					0, btnum);
> > -
> > -		bt_rec = (xfs_alloc_rec_t *)
> > -			  ((char *)bt_hdr + XFS_ALLOC_BLOCK_LEN(mp));
> > -		for (j = 0; j < be16_to_cpu(bt_hdr->bb_numrecs); j++) {
> > -			ASSERT(ext_ptr != NULL);
> > -			bt_rec[j].ar_startblock = cpu_to_be32(
> > -							ext_ptr->ex_startblock);
> > -			bt_rec[j].ar_blockcount = cpu_to_be32(
> > -							ext_ptr->ex_blockcount);
> > -			freeblks += ext_ptr->ex_blockcount;
> > -			if (btnum == XFS_BTNUM_BNO)
> > -				ext_ptr = findnext_bno_extent(ext_ptr);
> > -			else
> > -				ext_ptr = findnext_bcnt_extent(agno, ext_ptr);
> > -#if 0
> > -#ifdef XR_BLD_FREE_TRACE
> > -			if (ext_ptr == NULL)
> > -				fprintf(stderr, "null extent pointer, j = %d\n",
> > -					j);
> > -			else
> > -				fprintf(stderr,
> > -				"bft, agno = %d, start = %u, count = %u\n",
> > -					agno, ext_ptr->ex_startblock,
> > -					ext_ptr->ex_blockcount);
> > -#endif
> > -#endif
> > -		}
> > +	*freeblks = 0;
> > +	btr_cnt->bload.get_record = get_cntbt_record;
> > +	btr_cnt->bload.claim_block = rebuild_claim_block;
> > +	btr_cnt->bno_rec = findfirst_bcnt_extent(agno);
> > +	btr_cnt->freeblks = freeblks;
> >  
> > -		if (ext_ptr != NULL)  {
> > -			/*
> > -			 * get next leaf level block
> > -			 */
> > -			if (lptr->prev_buf_p != NULL)  {
> > -#ifdef XR_BLD_FREE_TRACE
> > -				fprintf(stderr, " writing fst agbno %u\n",
> > -					lptr->prev_agbno);
> > -#endif
> > -				ASSERT(lptr->prev_agbno != NULLAGBLOCK);
> > -				libxfs_buf_mark_dirty(lptr->prev_buf_p);
> > -				libxfs_buf_relse(lptr->prev_buf_p);
> > -			}
> > -			lptr->prev_buf_p = lptr->buf_p;
> > -			lptr->prev_agbno = lptr->agbno;
> > -			lptr->agbno = get_next_blockaddr(agno, 0, btree_curs);
> > -			bt_hdr->bb_u.s.bb_rightsib = cpu_to_be32(lptr->agbno);
> > +	error = -libxfs_trans_alloc_empty(sc->mp, &sc->tp);
> > +	if (error)
> > +		do_error(
> > +_("Insufficient memory to construct cntbt rebuild transaction.\n"));
> >  
> > -			error = -libxfs_buf_get(mp->m_dev,
> > -					XFS_AGB_TO_DADDR(mp, agno, lptr->agbno),
> > -					XFS_FSB_TO_BB(mp, 1),
> > -					&lptr->buf_p);
> > -			if (error)
> > -				do_error(
> > -	_("Cannot grab free space btree buffer, err=%d"),
> > -						error);
> > -		}
> > -	}
> > +	/* Add all observed cntbt records. */
> > +	error = -libxfs_btree_bload(btr_cnt->cur, &btr_cnt->bload, btr_cnt);
> > +	if (error)
> > +		do_error(
> > +_("Error %d while creating cntbt btree for AG %u.\n"), error, agno);
> >  
> > -	return(freeblks);
> > +	/* Since we're not writing the AGF yet, no need to commit the cursor */
> > +	libxfs_btree_del_cursor(btr_cnt->cur, 0);
> > +	error = -libxfs_trans_commit(sc->tp);
> > +	if (error)
> > +		do_error(
> > +_("Error %d while writing cntbt btree for AG %u.\n"), error, agno);
> > +	sc->tp = NULL;
> >  }
> >  
> >  /*
> > @@ -2233,6 +1897,27 @@ _("Insufficient memory to construct refcount cursor."));
> >  	free_slab_cursor(&refc_cur);
> >  }
> >  
> > +/* Fill the AGFL with any leftover bnobt rebuilder blocks. */
> > +static void
> > +fill_agfl(
> > +	struct bt_rebuild	*btr,
> > +	__be32			*agfl_bnos,
> > +	int			*i)
> > +{
> > +	struct xrep_newbt_resv	*resv, *n;
> > +	struct xfs_mount	*mp = btr->newbt.sc->mp;
> > +
> > +	for_each_xrep_newbt_reservation(&btr->newbt, resv, n) {
> > +		xfs_agblock_t	bno;
> > +
> > +		bno = XFS_FSB_TO_AGBNO(mp, resv->fsbno + resv->used);
> > +		while (resv->used < resv->len && (*i) < libxfs_agfl_size(mp)) {
> > +			agfl_bnos[(*i)++] = cpu_to_be32(bno++);
> > +			resv->used++;
> > +		}
> > +	}
> > +}
> > +
> >  /*
> >   * build both the agf and the agfl for an agno given both
> >   * btree cursors.
> > @@ -2243,8 +1928,8 @@ static void
> >  build_agf_agfl(
> >  	struct xfs_mount	*mp,
> >  	xfs_agnumber_t		agno,
> > -	struct bt_status	*bno_bt,
> > -	struct bt_status	*bcnt_bt,
> > +	struct bt_rebuild	*btr_bno,
> > +	struct bt_rebuild	*btr_cnt,
> >  	xfs_extlen_t		freeblks,	/* # free blocks in tree */
> >  	int			lostblocks,	/* # blocks that will be lost */
> >  	struct bt_status	*rmap_bt,
> > @@ -2256,7 +1941,6 @@ build_agf_agfl(
> >  	int			i;
> >  	struct xfs_agfl		*agfl;
> >  	struct xfs_agf		*agf;
> > -	xfs_fsblock_t		fsb;
> >  	__be32			*freelist;
> >  	int			error;
> >  
> > @@ -2288,10 +1972,14 @@ build_agf_agfl(
> >  		agf->agf_length = cpu_to_be32(mp->m_sb.sb_dblocks -
> >  			(xfs_rfsblock_t) mp->m_sb.sb_agblocks * agno);
> >  
> > -	agf->agf_roots[XFS_BTNUM_BNO] = cpu_to_be32(bno_bt->root);
> > -	agf->agf_levels[XFS_BTNUM_BNO] = cpu_to_be32(bno_bt->num_levels);
> > -	agf->agf_roots[XFS_BTNUM_CNT] = cpu_to_be32(bcnt_bt->root);
> > -	agf->agf_levels[XFS_BTNUM_CNT] = cpu_to_be32(bcnt_bt->num_levels);
> > +	agf->agf_roots[XFS_BTNUM_BNO] =
> > +			cpu_to_be32(btr_bno->newbt.afake.af_root);
> > +	agf->agf_levels[XFS_BTNUM_BNO] =
> > +			cpu_to_be32(btr_bno->newbt.afake.af_levels);
> > +	agf->agf_roots[XFS_BTNUM_CNT] =
> > +			cpu_to_be32(btr_cnt->newbt.afake.af_root);
> > +	agf->agf_levels[XFS_BTNUM_CNT] =
> > +			cpu_to_be32(btr_cnt->newbt.afake.af_levels);
> >  	agf->agf_roots[XFS_BTNUM_RMAP] = cpu_to_be32(rmap_bt->root);
> >  	agf->agf_levels[XFS_BTNUM_RMAP] = cpu_to_be32(rmap_bt->num_levels);
> >  	agf->agf_freeblks = cpu_to_be32(freeblks);
> > @@ -2311,9 +1999,8 @@ build_agf_agfl(
> >  		 * Don't count the root blocks as they are already
> >  		 * accounted for.
> >  		 */
> > -		blks = (bno_bt->num_tot_blocks - bno_bt->num_free_blocks) +
> > -			(bcnt_bt->num_tot_blocks - bcnt_bt->num_free_blocks) -
> > -			2;
> > +		blks = btr_bno->newbt.afake.af_blocks +
> > +			btr_cnt->newbt.afake.af_blocks - 2;
> >  		if (xfs_sb_version_hasrmapbt(&mp->m_sb))
> >  			blks += rmap_bt->num_tot_blocks - rmap_bt->num_free_blocks - 1;
> >  		agf->agf_btreeblks = cpu_to_be32(blks);
> > @@ -2357,49 +2044,14 @@ build_agf_agfl(
> >  	}
> >  
> >  	freelist = xfs_buf_to_agfl_bno(agfl_buf);
> > +	i = 0;
> >  
> > -	/*
> > -	 * 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. */
> > +	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);
> > @@ -2497,8 +2149,8 @@ phase5_func(
> >  	uint64_t		num_free_inos;
> >  	uint64_t		finobt_num_inos;
> >  	uint64_t		finobt_num_free_inos;
> > -	bt_status_t		bno_btree_curs;
> > -	bt_status_t		bcnt_btree_curs;
> > +	struct bt_rebuild	btr_bno;
> > +	struct bt_rebuild	btr_cnt;
> >  	bt_status_t		ino_btree_curs;
> >  	bt_status_t		fino_btree_curs;
> >  	bt_status_t		rmap_btree_curs;
> > @@ -2506,9 +2158,7 @@ phase5_func(
> >  	int			extra_blocks = 0;
> >  	uint			num_freeblocks;
> >  	xfs_extlen_t		freeblks1;
> > -#ifdef DEBUG
> >  	xfs_extlen_t		freeblks2;
> > -#endif
> >  	xfs_agblock_t		num_extents;
> >  
> >  	if (verbose)
> > @@ -2517,7 +2167,7 @@ phase5_func(
> >  	/*
> >  	 * build up incore bno and bcnt extent btrees
> >  	 */
> > -	num_extents = mk_incore_fstree(mp, agno);
> > +	num_extents = mk_incore_fstree(mp, agno, &num_freeblocks);
> >  
> >  #ifdef XR_BLD_FREE_TRACE
> >  	fprintf(stderr, "# of bno extents is %d\n",
> > @@ -2596,8 +2246,8 @@ phase5_func(
> >  	/*
> >  	 * track blocks that we might really lose
> >  	 */
> > -	extra_blocks = calculate_freespace_cursor(mp, agno,
> > -				&num_extents, &bno_btree_curs);
> > +	init_freespace_cursors(&sc, agno, num_freeblocks, &num_extents,
> > +			&extra_blocks, &btr_bno, &btr_cnt);
> >  
> >  	/*
> >  	 * freespace btrees live in the "free space" but
> > @@ -2615,13 +2265,6 @@ phase5_func(
> >  	if (extra_blocks > 0)
> >  		sb_fdblocks_ag[agno] -= extra_blocks;
> >  
> > -	bcnt_btree_curs = bno_btree_curs;
> > -
> > -	bno_btree_curs.owner = XFS_RMAP_OWN_AG;
> > -	bcnt_btree_curs.owner = XFS_RMAP_OWN_AG;
> > -	setup_cursor(mp, agno, &bno_btree_curs);
> > -	setup_cursor(mp, agno, &bcnt_btree_curs);
> > -
> >  #ifdef XR_BLD_FREE_TRACE
> >  	fprintf(stderr, "# of bno extents is %d\n",
> >  			count_bno_extents(agno));
> > @@ -2629,25 +2272,13 @@ phase5_func(
> >  			count_bcnt_extents(agno));
> >  #endif
> >  
> > -	/*
> > -	 * now rebuild the freespace trees
> > -	 */
> > -	freeblks1 = build_freespace_tree(mp, agno,
> > -				&bno_btree_curs, XFS_BTNUM_BNO);
> > +	/* Rebuild the freespace btrees. */
> > +	build_bnobt(&sc, agno, &btr_bno, &freeblks1);
> > +	build_cntbt(&sc, agno, &btr_cnt, &freeblks2);
> > +
> >  #ifdef XR_BLD_FREE_TRACE
> > -	fprintf(stderr, "# of free blocks == %d\n", freeblks1);
> > -#endif
> > -	write_cursor(&bno_btree_curs);
> > -
> > -#ifdef DEBUG
> > -	freeblks2 = build_freespace_tree(mp, agno,
> > -				&bcnt_btree_curs, XFS_BTNUM_CNT);
> > -#else
> > -	(void) build_freespace_tree(mp, agno,
> > -				&bcnt_btree_curs, XFS_BTNUM_CNT);
> > +	fprintf(stderr, "# of free blocks == %d/%d\n", freeblks1, freeblks2);
> >  #endif
> > -	write_cursor(&bcnt_btree_curs);
> > -
> >  	ASSERT(freeblks1 == freeblks2);
> >  
> >  	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
> > @@ -2665,9 +2296,9 @@ phase5_func(
> >  	/*
> >  	 * set up agf and agfl
> >  	 */
> > -	build_agf_agfl(mp, agno, &bno_btree_curs,
> > -			&bcnt_btree_curs, freeblks1, extra_blocks,
> > +	build_agf_agfl(mp, agno, &btr_bno, &btr_cnt, freeblks1, extra_blocks,
> >  			&rmap_btree_curs, &refcnt_btree_curs, lost_fsb);
> > +
> >  	/*
> >  	 * build inode allocation tree.
> >  	 */
> > @@ -2691,15 +2322,14 @@ phase5_func(
> >  	/*
> >  	 * tear down cursors
> >  	 */
> > -	finish_cursor(&bno_btree_curs);
> > -	finish_cursor(&ino_btree_curs);
> > +	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
> > 
>
Brian Foster May 15, 2020, 11:42 a.m. UTC | #3
On Thu, May 14, 2020 at 12:53:44PM -0700, Darrick J. Wong wrote:
> On Thu, May 14, 2020 at 11:12:05AM -0400, Brian Foster wrote:
> > On Sat, May 09, 2020 at 09:32:08AM -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          |  858 +++++++++++++---------------------------------
> > >  2 files changed, 247 insertions(+), 614 deletions(-)
> > > 
> > > 
> > ...
> > > diff --git a/repair/phase5.c b/repair/phase5.c
> > > index 7eb24519..94e4610c 100644
> > > --- a/repair/phase5.c
> > > +++ b/repair/phase5.c
> > ...
> > > @@ -465,7 +476,7 @@ _("error - not enough free space in filesystem\n"));
> > >  
> > >  /* Feed one of the new btree blocks to the bulk loader. */
> > >  static int
> > > -rebuild_alloc_block(
> > > +rebuild_claim_block(
> > >  	struct xfs_btree_cur	*cur,
> > >  	union xfs_btree_ptr	*ptr,
> > >  	void			*priv)
> > 
> > Hmm.. seems like a decent amount of churn here. The above function is
> > renamed and finish_rebuild() looks like it's gutted/replaced before
> > either is ever used. Can we get the core bits settled into the previous
> > patch(es) so they aren't changing when used to implement the tree
> > reconstructions?
> 
> I bet I committed all this churn to the wrong patch back when you and I
> were reviewing the similar patches for online repair.  Sorry I totally
> missed this, will fix for the next resend.
> 

No problem, thanks.

> (TBH I /really/ hate how diff tries to make the actual bnobt/cntbt
> rebuilder changes "comparable".  They're not, and it just makes
> reading this a nightmare.  Have kinda wondered if the new code should
> just go somewhere else so that phase5.c can shrink a bit...)
> 

I'd be fine with putting the rebuild bits in an infrastructure specific
source file or something instead of the historical phase5.c if it makes
the result cleaner, but I also don't generally expect to be able to
review patches straight from the diff so nbd to me either way.

It would be interesting if diff could be told to not intersperse changes
so much for a particular patch that's just replacing swaths of code.
Hmm... 'git show --patience' actually seems to help a bit with that on
this patch. Never knew that existed..

Brian

> --D
> 
> > Brian
> > 
> > > @@ -505,313 +516,32 @@ finish_cursor(bt_status_t *curs)
> > >  	free(curs->btree_blocks);
> > >  }
> > >  
> > > +/*
> > > + * Scoop up leftovers from a rebuild cursor for later freeing, then free the
> > > + * rebuild context.
> > > + */
> > >  static void
> > >  finish_rebuild(
> > >  	struct xfs_mount	*mp,
> > > -	struct bt_rebuild	*btr)
> > > +	struct bt_rebuild	*btr,
> > > +	struct xfs_slab		*lost_fsb)
> > >  {
> > >  	struct xrep_newbt_resv	*resv, *n;
> > >  
> > >  	for_each_xrep_newbt_reservation(&btr->newbt, resv, n) {
> > > -		xfs_agnumber_t	agno;
> > > -		xfs_agblock_t	bno;
> > > -		xfs_extlen_t	len;
> > > -
> > > -		if (resv->used >= resv->len)
> > > -			continue;
> > > -
> > > -		/* XXX: Shouldn't this go on the AGFL? */
> > > -		/* Put back everything we didn't use. */
> > > -		bno = XFS_FSB_TO_AGBNO(mp, resv->fsbno + resv->used);
> > > -		agno = XFS_FSB_TO_AGNO(mp, resv->fsbno + resv->used);
> > > -		len = resv->len - resv->used;
> > > -
> > > -		add_bno_extent(agno, bno, len);
> > > -		add_bcnt_extent(agno, bno, len);
> > > -	}
> > > -
> > > -	xrep_newbt_destroy(&btr->newbt, 0);
> > > -}
> > > -
> > > -/*
> > > - * We need to leave some free records in the tree for the corner case of
> > > - * setting up the AGFL. This may require allocation of blocks, and as
> > > - * such can require insertion of new records into the tree (e.g. moving
> > > - * a record in the by-count tree when a long extent is shortened). If we
> > > - * pack the records into the leaves with no slack space, this requires a
> > > - * leaf split to occur and a block to be allocated from the free list.
> > > - * If we don't have any blocks on the free list (because we are setting
> > > - * it up!), then we fail, and the filesystem will fail with the same
> > > - * failure at runtime. Hence leave a couple of records slack space in
> > > - * each block to allow immediate modification of the tree without
> > > - * requiring splits to be done.
> > > - *
> > > - * XXX(hch): any reason we don't just look at mp->m_alloc_mxr?
> > > - */
> > > -#define XR_ALLOC_BLOCK_MAXRECS(mp, level) \
> > > -	(libxfs_allocbt_maxrecs((mp), (mp)->m_sb.sb_blocksize, (level) == 0) - 2)
> > > -
> > > -/*
> > > - * this calculates a freespace cursor for an ag.
> > > - * btree_curs is an in/out.  returns the number of
> > > - * blocks that will show up in the AGFL.
> > > - */
> > > -static int
> > > -calculate_freespace_cursor(xfs_mount_t *mp, xfs_agnumber_t agno,
> > > -			xfs_agblock_t *extents, bt_status_t *btree_curs)
> > > -{
> > > -	xfs_extlen_t		blocks_needed;		/* a running count */
> > > -	xfs_extlen_t		blocks_allocated_pt;	/* per tree */
> > > -	xfs_extlen_t		blocks_allocated_total;	/* for both trees */
> > > -	xfs_agblock_t		num_extents;
> > > -	int			i;
> > > -	int			extents_used;
> > > -	int			extra_blocks;
> > > -	bt_stat_level_t		*lptr;
> > > -	bt_stat_level_t		*p_lptr;
> > > -	extent_tree_node_t	*ext_ptr;
> > > -	int			level;
> > > -
> > > -	num_extents = *extents;
> > > -	extents_used = 0;
> > > -
> > > -	ASSERT(num_extents != 0);
> > > -
> > > -	lptr = &btree_curs->level[0];
> > > -	btree_curs->init = 1;
> > > +		while (resv->used < resv->len) {
> > > +			xfs_fsblock_t	fsb = resv->fsbno + resv->used;
> > > +			int		error;
> > >  
> > > -	/*
> > > -	 * figure out how much space we need for the leaf level
> > > -	 * of the tree and set up the cursor for the leaf level
> > > -	 * (note that the same code is duplicated further down)
> > > -	 */
> > > -	lptr->num_blocks = howmany(num_extents, XR_ALLOC_BLOCK_MAXRECS(mp, 0));
> > > -	lptr->num_recs_pb = num_extents / lptr->num_blocks;
> > > -	lptr->modulo = num_extents % lptr->num_blocks;
> > > -	lptr->num_recs_tot = num_extents;
> > > -	level = 1;
> > > -
> > > -#ifdef XR_BLD_FREE_TRACE
> > > -	fprintf(stderr, "%s 0 %d %d %d %d\n", __func__,
> > > -			lptr->num_blocks,
> > > -			lptr->num_recs_pb,
> > > -			lptr->modulo,
> > > -			lptr->num_recs_tot);
> > > -#endif
> > > -	/*
> > > -	 * if we need more levels, set them up.  # of records
> > > -	 * per level is the # of blocks in the level below it
> > > -	 */
> > > -	if (lptr->num_blocks > 1)  {
> > > -		for (; btree_curs->level[level - 1].num_blocks > 1
> > > -				&& level < XFS_BTREE_MAXLEVELS;
> > > -				level++)  {
> > > -			lptr = &btree_curs->level[level];
> > > -			p_lptr = &btree_curs->level[level - 1];
> > > -			lptr->num_blocks = howmany(p_lptr->num_blocks,
> > > -					XR_ALLOC_BLOCK_MAXRECS(mp, level));
> > > -			lptr->modulo = p_lptr->num_blocks
> > > -					% lptr->num_blocks;
> > > -			lptr->num_recs_pb = p_lptr->num_blocks
> > > -					/ lptr->num_blocks;
> > > -			lptr->num_recs_tot = p_lptr->num_blocks;
> > > -#ifdef XR_BLD_FREE_TRACE
> > > -			fprintf(stderr, "%s %d %d %d %d %d\n", __func__,
> > > -					level,
> > > -					lptr->num_blocks,
> > > -					lptr->num_recs_pb,
> > > -					lptr->modulo,
> > > -					lptr->num_recs_tot);
> > > -#endif
> > > -		}
> > > -	}
> > > -
> > > -	ASSERT(lptr->num_blocks == 1);
> > > -	btree_curs->num_levels = level;
> > > -
> > > -	/*
> > > -	 * ok, now we have a hypothetical cursor that
> > > -	 * will work for both the bno and bcnt trees.
> > > -	 * now figure out if using up blocks to set up the
> > > -	 * trees will perturb the shape of the freespace tree.
> > > -	 * if so, we've over-allocated.  the freespace trees
> > > -	 * as they will be *after* accounting for the free space
> > > -	 * we've used up will need fewer blocks to to represent
> > > -	 * than we've allocated.  We can use the AGFL to hold
> > > -	 * xfs_agfl_size (sector/struct xfs_agfl) blocks but that's it.
> > > -	 * Thus we limit things to xfs_agfl_size/2 for each of the 2 btrees.
> > > -	 * if the number of extra blocks is more than that,
> > > -	 * we'll have to be called again.
> > > -	 */
> > > -	for (blocks_needed = 0, i = 0; i < level; i++)  {
> > > -		blocks_needed += btree_curs->level[i].num_blocks;
> > > -	}
> > > -
> > > -	/*
> > > -	 * record the # of blocks we've allocated
> > > -	 */
> > > -	blocks_allocated_pt = blocks_needed;
> > > -	blocks_needed *= 2;
> > > -	blocks_allocated_total = blocks_needed;
> > > -
> > > -	/*
> > > -	 * figure out how many free extents will be used up by
> > > -	 * our space allocation
> > > -	 */
> > > -	if ((ext_ptr = findfirst_bcnt_extent(agno)) == NULL)
> > > -		do_error(_("can't rebuild fs trees -- not enough free space "
> > > -			   "on ag %u\n"), agno);
> > > -
> > > -	while (ext_ptr != NULL && blocks_needed > 0)  {
> > > -		if (ext_ptr->ex_blockcount <= blocks_needed)  {
> > > -			blocks_needed -= ext_ptr->ex_blockcount;
> > > -			extents_used++;
> > > -		} else  {
> > > -			blocks_needed = 0;
> > > -		}
> > > -
> > > -		ext_ptr = findnext_bcnt_extent(agno, ext_ptr);
> > > -
> > > -#ifdef XR_BLD_FREE_TRACE
> > > -		if (ext_ptr != NULL)  {
> > > -			fprintf(stderr, "got next extent [%u %u]\n",
> > > -				ext_ptr->ex_startblock, ext_ptr->ex_blockcount);
> > > -		} else  {
> > > -			fprintf(stderr, "out of extents\n");
> > > -		}
> > > -#endif
> > > -	}
> > > -	if (blocks_needed > 0)
> > > -		do_error(_("ag %u - not enough free space to build freespace "
> > > -			   "btrees\n"), agno);
> > > -
> > > -	ASSERT(num_extents >= extents_used);
> > > -
> > > -	num_extents -= extents_used;
> > > -
> > > -	/*
> > > -	 * see if the number of leaf blocks will change as a result
> > > -	 * of the number of extents changing
> > > -	 */
> > > -	if (howmany(num_extents, XR_ALLOC_BLOCK_MAXRECS(mp, 0))
> > > -			!= btree_curs->level[0].num_blocks)  {
> > > -		/*
> > > -		 * yes -- recalculate the cursor.  If the number of
> > > -		 * excess (overallocated) blocks is < xfs_agfl_size/2, we're ok.
> > > -		 * we can put those into the AGFL.  we don't try
> > > -		 * and get things to converge exactly (reach a
> > > -		 * state with zero excess blocks) because there
> > > -		 * exist pathological cases which will never
> > > -		 * converge.  first, check for the zero-case.
> > > -		 */
> > > -		if (num_extents == 0)  {
> > > -			/*
> > > -			 * ok, we've used up all the free blocks
> > > -			 * trying to lay out the leaf level. go
> > > -			 * to a one block (empty) btree and put the
> > > -			 * already allocated blocks into the AGFL
> > > -			 */
> > > -			if (btree_curs->level[0].num_blocks != 1)  {
> > > -				/*
> > > -				 * we really needed more blocks because
> > > -				 * the old tree had more than one level.
> > > -				 * this is bad.
> > > -				 */
> > > -				 do_warn(_("not enough free blocks left to "
> > > -					   "describe all free blocks in AG "
> > > -					   "%u\n"), agno);
> > > -			}
> > > -#ifdef XR_BLD_FREE_TRACE
> > > -			fprintf(stderr,
> > > -				"ag %u -- no free extents, alloc'ed %d\n",
> > > -				agno, blocks_allocated_pt);
> > > -#endif
> > > -			lptr->num_blocks = 1;
> > > -			lptr->modulo = 0;
> > > -			lptr->num_recs_pb = 0;
> > > -			lptr->num_recs_tot = 0;
> > > -
> > > -			btree_curs->num_levels = 1;
> > > -
> > > -			/*
> > > -			 * don't reset the allocation stats, assume
> > > -			 * they're all extra blocks
> > > -			 * don't forget to return the total block count
> > > -			 * not the per-tree block count.  these are the
> > > -			 * extras that will go into the AGFL.  subtract
> > > -			 * two for the root blocks.
> > > -			 */
> > > -			btree_curs->num_tot_blocks = blocks_allocated_pt;
> > > -			btree_curs->num_free_blocks = blocks_allocated_pt;
> > > -
> > > -			*extents = 0;
> > > -
> > > -			return(blocks_allocated_total - 2);
> > > -		}
> > > -
> > > -		lptr = &btree_curs->level[0];
> > > -		lptr->num_blocks = howmany(num_extents,
> > > -					XR_ALLOC_BLOCK_MAXRECS(mp, 0));
> > > -		lptr->num_recs_pb = num_extents / lptr->num_blocks;
> > > -		lptr->modulo = num_extents % lptr->num_blocks;
> > > -		lptr->num_recs_tot = num_extents;
> > > -		level = 1;
> > > -
> > > -		/*
> > > -		 * if we need more levels, set them up
> > > -		 */
> > > -		if (lptr->num_blocks > 1)  {
> > > -			for (level = 1; btree_curs->level[level-1].num_blocks
> > > -					> 1 && level < XFS_BTREE_MAXLEVELS;
> > > -					level++)  {
> > > -				lptr = &btree_curs->level[level];
> > > -				p_lptr = &btree_curs->level[level-1];
> > > -				lptr->num_blocks = howmany(p_lptr->num_blocks,
> > > -					XR_ALLOC_BLOCK_MAXRECS(mp, level));
> > > -				lptr->modulo = p_lptr->num_blocks
> > > -						% lptr->num_blocks;
> > > -				lptr->num_recs_pb = p_lptr->num_blocks
> > > -						/ lptr->num_blocks;
> > > -				lptr->num_recs_tot = p_lptr->num_blocks;
> > > -			}
> > > -		}
> > > -		ASSERT(lptr->num_blocks == 1);
> > > -		btree_curs->num_levels = level;
> > > -
> > > -		/*
> > > -		 * now figure out the number of excess blocks
> > > -		 */
> > > -		for (blocks_needed = 0, i = 0; i < level; i++)  {
> > > -			blocks_needed += btree_curs->level[i].num_blocks;
> > > -		}
> > > -		blocks_needed *= 2;
> > > -
> > > -		ASSERT(blocks_allocated_total >= blocks_needed);
> > > -		extra_blocks = blocks_allocated_total - blocks_needed;
> > > -	} else  {
> > > -		if (extents_used > 0) {
> > > -			/*
> > > -			 * reset the leaf level geometry to account
> > > -			 * for consumed extents.  we can leave the
> > > -			 * rest of the cursor alone since the number
> > > -			 * of leaf blocks hasn't changed.
> > > -			 */
> > > -			lptr = &btree_curs->level[0];
> > > -
> > > -			lptr->num_recs_pb = num_extents / lptr->num_blocks;
> > > -			lptr->modulo = num_extents % lptr->num_blocks;
> > > -			lptr->num_recs_tot = num_extents;
> > > +			error = slab_add(lost_fsb, &fsb);
> > > +			if (error)
> > > +				do_error(
> > > +_("Insufficient memory saving lost blocks.\n"));
> > > +			resv->used++;
> > >  		}
> > > -
> > > -		extra_blocks = 0;
> > >  	}
> > >  
> > > -	btree_curs->num_tot_blocks = blocks_allocated_pt;
> > > -	btree_curs->num_free_blocks = blocks_allocated_pt;
> > > -
> > > -	*extents = num_extents;
> > > -
> > > -	return(extra_blocks);
> > > +	xrep_newbt_destroy(&btr->newbt, 0);
> > >  }
> > >  
> > >  /* Map btnum to buffer ops for the types that need it. */
> > > @@ -838,268 +568,202 @@ btnum_to_ops(
> > >  	}
> > >  }
> > >  
> > > +/*
> > > + * Free Space Btrees
> > > + *
> > > + * We need to leave some free records in the tree for the corner case of
> > > + * setting up the AGFL. This may require allocation of blocks, and as
> > > + * such can require insertion of new records into the tree (e.g. moving
> > > + * a record in the by-count tree when a long extent is shortened). If we
> > > + * pack the records into the leaves with no slack space, this requires a
> > > + * leaf split to occur and a block to be allocated from the free list.
> > > + * If we don't have any blocks on the free list (because we are setting
> > > + * it up!), then we fail, and the filesystem will fail with the same
> > > + * failure at runtime. Hence leave a couple of records slack space in
> > > + * each block to allow immediate modification of the tree without
> > > + * requiring splits to be done.
> > > + */
> > > +
> > >  static void
> > > -prop_freespace_cursor(xfs_mount_t *mp, xfs_agnumber_t agno,
> > > -		bt_status_t *btree_curs, xfs_agblock_t startblock,
> > > -		xfs_extlen_t blockcount, int level, xfs_btnum_t btnum)
> > > +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)
> > >  {
> > > -	struct xfs_btree_block	*bt_hdr;
> > > -	xfs_alloc_key_t		*bt_key;
> > > -	xfs_alloc_ptr_t		*bt_ptr;
> > > -	xfs_agblock_t		agbno;
> > > -	bt_stat_level_t		*lptr;
> > > -	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);
> > > +	init_rebuild(sc, &XFS_RMAP_OINFO_AG, free_space, btr_bno);
> > > +	init_rebuild(sc, &XFS_RMAP_OINFO_AG, free_space, btr_cnt);
> > >  
> > > -	level++;
> > > -
> > > -	if (level >= btree_curs->num_levels)
> > > -		return;
> > > -
> > > -	lptr = &btree_curs->level[level];
> > > -	bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
> > > -
> > > -	if (be16_to_cpu(bt_hdr->bb_numrecs) == 0)  {
> > > -		/*
> > > -		 * only happens once when initializing the
> > > -		 * left-hand side of the tree.
> > > -		 */
> > > -		prop_freespace_cursor(mp, agno, btree_curs, startblock,
> > > -				blockcount, level, btnum);
> > > -	}
> > > +	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);
> > >  
> > > -	if (be16_to_cpu(bt_hdr->bb_numrecs) ==
> > > -				lptr->num_recs_pb + (lptr->modulo > 0))  {
> > > -		/*
> > > -		 * write out current prev block, grab us a new block,
> > > -		 * and set the rightsib pointer of current block
> > > -		 */
> > > -#ifdef XR_BLD_FREE_TRACE
> > > -		fprintf(stderr, " %d ", lptr->prev_agbno);
> > > -#endif
> > > -		if (lptr->prev_agbno != NULLAGBLOCK) {
> > > -			ASSERT(lptr->prev_buf_p != NULL);
> > > -			libxfs_buf_mark_dirty(lptr->prev_buf_p);
> > > -			libxfs_buf_relse(lptr->prev_buf_p);
> > > -		}
> > > -		lptr->prev_agbno = lptr->agbno;;
> > > -		lptr->prev_buf_p = lptr->buf_p;
> > > -		agbno = get_next_blockaddr(agno, level, btree_curs);
> > > +	/*
> > > +	 * 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.
> > > +	 */
> > > +	do {
> > > +		unsigned int	num_freeblocks;
> > >  
> > > -		bt_hdr->bb_u.s.bb_rightsib = cpu_to_be32(agbno);
> > > +		bno_blocks = btr_bno->bload.nr_blocks;
> > > +		cnt_blocks = btr_cnt->bload.nr_blocks;
> > >  
> > > -		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(
> > > -	_("Cannot grab free space btree buffer, err=%d"),
> > > -					error);
> > > -		lptr->agbno = agbno;
> > > +_("Unable to compute free space by block btree geometry, error %d.\n"), -error);
> > >  
> > > -		if (lptr->modulo)
> > > -			lptr->modulo--;
> > > -
> > > -		/*
> > > -		 * initialize block header
> > > -		 */
> > > -		lptr->buf_p->b_ops = ops;
> > > -		bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
> > > -		memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
> > > -		libxfs_btree_init_block(mp, lptr->buf_p, btnum, level,
> > > -					0, agno);
> > > +		/* Compute how many cntbt blocks we'll need. */
> > > +		error = -libxfs_btree_bload_compute_geometry(btr_bno->cur,
> > > +				&btr_cnt->bload, *nr_extents);
> > > +		if (error)
> > > +			do_error(
> > > +_("Unable to compute free space by length btree geometry, error %d.\n"), -error);
> > >  
> > > -		bt_hdr->bb_u.s.bb_leftsib = cpu_to_be32(lptr->prev_agbno);
> > > +		/* 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;
> > >  
> > > -		/*
> > > -		 * propagate extent record for first extent in new block up
> > > -		 */
> > > -		prop_freespace_cursor(mp, agno, btree_curs, startblock,
> > > -				blockcount, level, btnum);
> > > -	}
> > > -	/*
> > > -	 * add extent info to current block
> > > -	 */
> > > -	be16_add_cpu(&bt_hdr->bb_numrecs, 1);
> > > +		/* 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);
> > >  
> > > -	bt_key = XFS_ALLOC_KEY_ADDR(mp, bt_hdr,
> > > -				be16_to_cpu(bt_hdr->bb_numrecs));
> > > -	bt_ptr = XFS_ALLOC_PTR_ADDR(mp, bt_hdr,
> > > -				be16_to_cpu(bt_hdr->bb_numrecs),
> > > -				mp->m_alloc_mxr[1]);
> > > +		/* Ok, now how many free space records do we have? */
> > > +		*nr_extents = count_bno_extents_blocks(agno, &num_freeblocks);
> > > +	} while (1);
> > >  
> > > -	bt_key->ar_startblock = cpu_to_be32(startblock);
> > > -	bt_key->ar_blockcount = cpu_to_be32(blockcount);
> > > -	*bt_ptr = cpu_to_be32(btree_curs->level[level-1].agbno);
> > > +	*extra_blocks = (bno_blocks - btr_bno->bload.nr_blocks) +
> > > +			(cnt_blocks - btr_cnt->bload.nr_blocks);
> > >  }
> > >  
> > > -/*
> > > - * rebuilds a freespace tree given a cursor and type
> > > - * of tree to build (bno or bcnt).  returns the number of free blocks
> > > - * represented by the tree.
> > > - */
> > > -static xfs_extlen_t
> > > -build_freespace_tree(xfs_mount_t *mp, xfs_agnumber_t agno,
> > > -		bt_status_t *btree_curs, xfs_btnum_t btnum)
> > > +static void
> > > +get_freesp_data(
> > > +	struct xfs_btree_cur		*cur,
> > > +	struct extent_tree_node		*bno_rec,
> > > +	xfs_agblock_t			*freeblks)
> > >  {
> > > -	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);
> > > -	int			error;
> > > +	struct xfs_alloc_rec_incore	*arec = &cur->bc_rec.a;
> > >  
> > > -	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;
> > > +	arec->ar_startblock = bno_rec->ex_startblock;
> > > +	arec->ar_blockcount = bno_rec->ex_blockcount;
> > > +	if (freeblks)
> > > +		*freeblks += bno_rec->ex_blockcount;
> > > +}
> > >  
> > > -	ASSERT(level > 0);
> > > +/* Grab one bnobt record. */
> > > +static int
> > > +get_bnobt_record(
> > > +	struct xfs_btree_cur		*cur,
> > > +	void				*priv)
> > > +{
> > > +	struct bt_rebuild		*btr = priv;
> > >  
> > > -	/*
> > > -	 * initialize the first block on each btree level
> > > -	 */
> > > -	for (i = 0; i < level; i++)  {
> > > -		lptr = &btree_curs->level[i];
> > > +	get_freesp_data(cur, btr->bno_rec, btr->freeblks);
> > > +	btr->bno_rec = findnext_bno_extent(btr->bno_rec);
> > > +	return 0;
> > > +}
> > >  
> > > -		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);
> > > -		if (error)
> > > -			do_error(
> > > -	_("Cannot grab free space btree buffer, err=%d"),
> > > -					error);
> > > +/* 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;
> > >  
> > > -		if (i == btree_curs->num_levels - 1)
> > > -			btree_curs->root = agbno;
> > > +	*freeblks = 0;
> > > +	btr_bno->bload.get_record = get_bnobt_record;
> > > +	btr_bno->bload.claim_block = rebuild_claim_block;
> > > +	btr_bno->bno_rec = findfirst_bno_extent(agno);
> > > +	btr_bno->freeblks = freeblks;
> > >  
> > > -		lptr->agbno = agbno;
> > > -		lptr->prev_agbno = NULLAGBLOCK;
> > > -		lptr->prev_buf_p = NULL;
> > > -		/*
> > > -		 * initialize block header
> > > -		 */
> > > -		lptr->buf_p->b_ops = ops;
> > > -		bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
> > > -		memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
> > > -		libxfs_btree_init_block(mp, lptr->buf_p, btnum, i, 0, agno);
> > > -	}
> > > -	/*
> > > -	 * run along leaf, setting up records.  as we have to switch
> > > -	 * blocks, call the prop_freespace_cursor routine to set up the new
> > > -	 * pointers for the parent.  that can recurse up to the root
> > > -	 * if required.  set the sibling pointers for leaf level here.
> > > -	 */
> > > -	if (btnum == XFS_BTNUM_BNO)
> > > -		ext_ptr = findfirst_bno_extent(agno);
> > > -	else
> > > -		ext_ptr = findfirst_bcnt_extent(agno);
> > > +	error = -libxfs_trans_alloc_empty(sc->mp, &sc->tp);
> > > +	if (error)
> > > +		do_error(
> > > +_("Insufficient memory to construct bnobt rebuild transaction.\n"));
> > >  
> > > -#ifdef XR_BLD_FREE_TRACE
> > > -	fprintf(stderr, "bft, agno = %d, start = %u, count = %u\n",
> > > -		agno, ext_ptr->ex_startblock, ext_ptr->ex_blockcount);
> > > -#endif
> > > +	/* 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);
> > >  
> > > -	lptr = &btree_curs->level[0];
> > > +	/* 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;
> > > +}
> > >  
> > > -	for (i = 0; i < btree_curs->level[0].num_blocks; i++)  {
> > > -		/*
> > > -		 * block initialization, lay in block header
> > > -		 */
> > > -		lptr->buf_p->b_ops = ops;
> > > -		bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
> > > -		memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
> > > -		libxfs_btree_init_block(mp, lptr->buf_p, btnum, 0, 0, agno);
> > > +/* Grab one cntbt record. */
> > > +static int
> > > +get_cntbt_record(
> > > +	struct xfs_btree_cur		*cur,
> > > +	void				*priv)
> > > +{
> > > +	struct bt_rebuild		*btr = priv;
> > >  
> > > -		bt_hdr->bb_u.s.bb_leftsib = cpu_to_be32(lptr->prev_agbno);
> > > -		bt_hdr->bb_numrecs = cpu_to_be16(lptr->num_recs_pb +
> > > -							(lptr->modulo > 0));
> > > -#ifdef XR_BLD_FREE_TRACE
> > > -		fprintf(stderr, "bft, bb_numrecs = %d\n",
> > > -				be16_to_cpu(bt_hdr->bb_numrecs));
> > > -#endif
> > > +	get_freesp_data(cur, btr->bno_rec, btr->freeblks);
> > > +	btr->bno_rec = findnext_bcnt_extent(cur->bc_ag.agno, btr->bno_rec);
> > > +	return 0;
> > > +}
> > >  
> > > -		if (lptr->modulo > 0)
> > > -			lptr->modulo--;
> > > +/* Rebuild a freespace by count btree. */
> > > +static void
> > > +build_cntbt(
> > > +	struct repair_ctx	*sc,
> > > +	xfs_agnumber_t		agno,
> > > +	struct bt_rebuild	*btr_cnt,
> > > +	xfs_agblock_t		*freeblks)
> > > +{
> > > +	int			error;
> > >  
> > > -		/*
> > > -		 * initialize values in the path up to the root if
> > > -		 * this is a multi-level btree
> > > -		 */
> > > -		if (btree_curs->num_levels > 1)
> > > -			prop_freespace_cursor(mp, agno, btree_curs,
> > > -					ext_ptr->ex_startblock,
> > > -					ext_ptr->ex_blockcount,
> > > -					0, btnum);
> > > -
> > > -		bt_rec = (xfs_alloc_rec_t *)
> > > -			  ((char *)bt_hdr + XFS_ALLOC_BLOCK_LEN(mp));
> > > -		for (j = 0; j < be16_to_cpu(bt_hdr->bb_numrecs); j++) {
> > > -			ASSERT(ext_ptr != NULL);
> > > -			bt_rec[j].ar_startblock = cpu_to_be32(
> > > -							ext_ptr->ex_startblock);
> > > -			bt_rec[j].ar_blockcount = cpu_to_be32(
> > > -							ext_ptr->ex_blockcount);
> > > -			freeblks += ext_ptr->ex_blockcount;
> > > -			if (btnum == XFS_BTNUM_BNO)
> > > -				ext_ptr = findnext_bno_extent(ext_ptr);
> > > -			else
> > > -				ext_ptr = findnext_bcnt_extent(agno, ext_ptr);
> > > -#if 0
> > > -#ifdef XR_BLD_FREE_TRACE
> > > -			if (ext_ptr == NULL)
> > > -				fprintf(stderr, "null extent pointer, j = %d\n",
> > > -					j);
> > > -			else
> > > -				fprintf(stderr,
> > > -				"bft, agno = %d, start = %u, count = %u\n",
> > > -					agno, ext_ptr->ex_startblock,
> > > -					ext_ptr->ex_blockcount);
> > > -#endif
> > > -#endif
> > > -		}
> > > +	*freeblks = 0;
> > > +	btr_cnt->bload.get_record = get_cntbt_record;
> > > +	btr_cnt->bload.claim_block = rebuild_claim_block;
> > > +	btr_cnt->bno_rec = findfirst_bcnt_extent(agno);
> > > +	btr_cnt->freeblks = freeblks;
> > >  
> > > -		if (ext_ptr != NULL)  {
> > > -			/*
> > > -			 * get next leaf level block
> > > -			 */
> > > -			if (lptr->prev_buf_p != NULL)  {
> > > -#ifdef XR_BLD_FREE_TRACE
> > > -				fprintf(stderr, " writing fst agbno %u\n",
> > > -					lptr->prev_agbno);
> > > -#endif
> > > -				ASSERT(lptr->prev_agbno != NULLAGBLOCK);
> > > -				libxfs_buf_mark_dirty(lptr->prev_buf_p);
> > > -				libxfs_buf_relse(lptr->prev_buf_p);
> > > -			}
> > > -			lptr->prev_buf_p = lptr->buf_p;
> > > -			lptr->prev_agbno = lptr->agbno;
> > > -			lptr->agbno = get_next_blockaddr(agno, 0, btree_curs);
> > > -			bt_hdr->bb_u.s.bb_rightsib = cpu_to_be32(lptr->agbno);
> > > +	error = -libxfs_trans_alloc_empty(sc->mp, &sc->tp);
> > > +	if (error)
> > > +		do_error(
> > > +_("Insufficient memory to construct cntbt rebuild transaction.\n"));
> > >  
> > > -			error = -libxfs_buf_get(mp->m_dev,
> > > -					XFS_AGB_TO_DADDR(mp, agno, lptr->agbno),
> > > -					XFS_FSB_TO_BB(mp, 1),
> > > -					&lptr->buf_p);
> > > -			if (error)
> > > -				do_error(
> > > -	_("Cannot grab free space btree buffer, err=%d"),
> > > -						error);
> > > -		}
> > > -	}
> > > +	/* Add all observed cntbt records. */
> > > +	error = -libxfs_btree_bload(btr_cnt->cur, &btr_cnt->bload, btr_cnt);
> > > +	if (error)
> > > +		do_error(
> > > +_("Error %d while creating cntbt btree for AG %u.\n"), error, agno);
> > >  
> > > -	return(freeblks);
> > > +	/* Since we're not writing the AGF yet, no need to commit the cursor */
> > > +	libxfs_btree_del_cursor(btr_cnt->cur, 0);
> > > +	error = -libxfs_trans_commit(sc->tp);
> > > +	if (error)
> > > +		do_error(
> > > +_("Error %d while writing cntbt btree for AG %u.\n"), error, agno);
> > > +	sc->tp = NULL;
> > >  }
> > >  
> > >  /*
> > > @@ -2233,6 +1897,27 @@ _("Insufficient memory to construct refcount cursor."));
> > >  	free_slab_cursor(&refc_cur);
> > >  }
> > >  
> > > +/* Fill the AGFL with any leftover bnobt rebuilder blocks. */
> > > +static void
> > > +fill_agfl(
> > > +	struct bt_rebuild	*btr,
> > > +	__be32			*agfl_bnos,
> > > +	int			*i)
> > > +{
> > > +	struct xrep_newbt_resv	*resv, *n;
> > > +	struct xfs_mount	*mp = btr->newbt.sc->mp;
> > > +
> > > +	for_each_xrep_newbt_reservation(&btr->newbt, resv, n) {
> > > +		xfs_agblock_t	bno;
> > > +
> > > +		bno = XFS_FSB_TO_AGBNO(mp, resv->fsbno + resv->used);
> > > +		while (resv->used < resv->len && (*i) < libxfs_agfl_size(mp)) {
> > > +			agfl_bnos[(*i)++] = cpu_to_be32(bno++);
> > > +			resv->used++;
> > > +		}
> > > +	}
> > > +}
> > > +
> > >  /*
> > >   * build both the agf and the agfl for an agno given both
> > >   * btree cursors.
> > > @@ -2243,8 +1928,8 @@ static void
> > >  build_agf_agfl(
> > >  	struct xfs_mount	*mp,
> > >  	xfs_agnumber_t		agno,
> > > -	struct bt_status	*bno_bt,
> > > -	struct bt_status	*bcnt_bt,
> > > +	struct bt_rebuild	*btr_bno,
> > > +	struct bt_rebuild	*btr_cnt,
> > >  	xfs_extlen_t		freeblks,	/* # free blocks in tree */
> > >  	int			lostblocks,	/* # blocks that will be lost */
> > >  	struct bt_status	*rmap_bt,
> > > @@ -2256,7 +1941,6 @@ build_agf_agfl(
> > >  	int			i;
> > >  	struct xfs_agfl		*agfl;
> > >  	struct xfs_agf		*agf;
> > > -	xfs_fsblock_t		fsb;
> > >  	__be32			*freelist;
> > >  	int			error;
> > >  
> > > @@ -2288,10 +1972,14 @@ build_agf_agfl(
> > >  		agf->agf_length = cpu_to_be32(mp->m_sb.sb_dblocks -
> > >  			(xfs_rfsblock_t) mp->m_sb.sb_agblocks * agno);
> > >  
> > > -	agf->agf_roots[XFS_BTNUM_BNO] = cpu_to_be32(bno_bt->root);
> > > -	agf->agf_levels[XFS_BTNUM_BNO] = cpu_to_be32(bno_bt->num_levels);
> > > -	agf->agf_roots[XFS_BTNUM_CNT] = cpu_to_be32(bcnt_bt->root);
> > > -	agf->agf_levels[XFS_BTNUM_CNT] = cpu_to_be32(bcnt_bt->num_levels);
> > > +	agf->agf_roots[XFS_BTNUM_BNO] =
> > > +			cpu_to_be32(btr_bno->newbt.afake.af_root);
> > > +	agf->agf_levels[XFS_BTNUM_BNO] =
> > > +			cpu_to_be32(btr_bno->newbt.afake.af_levels);
> > > +	agf->agf_roots[XFS_BTNUM_CNT] =
> > > +			cpu_to_be32(btr_cnt->newbt.afake.af_root);
> > > +	agf->agf_levels[XFS_BTNUM_CNT] =
> > > +			cpu_to_be32(btr_cnt->newbt.afake.af_levels);
> > >  	agf->agf_roots[XFS_BTNUM_RMAP] = cpu_to_be32(rmap_bt->root);
> > >  	agf->agf_levels[XFS_BTNUM_RMAP] = cpu_to_be32(rmap_bt->num_levels);
> > >  	agf->agf_freeblks = cpu_to_be32(freeblks);
> > > @@ -2311,9 +1999,8 @@ build_agf_agfl(
> > >  		 * Don't count the root blocks as they are already
> > >  		 * accounted for.
> > >  		 */
> > > -		blks = (bno_bt->num_tot_blocks - bno_bt->num_free_blocks) +
> > > -			(bcnt_bt->num_tot_blocks - bcnt_bt->num_free_blocks) -
> > > -			2;
> > > +		blks = btr_bno->newbt.afake.af_blocks +
> > > +			btr_cnt->newbt.afake.af_blocks - 2;
> > >  		if (xfs_sb_version_hasrmapbt(&mp->m_sb))
> > >  			blks += rmap_bt->num_tot_blocks - rmap_bt->num_free_blocks - 1;
> > >  		agf->agf_btreeblks = cpu_to_be32(blks);
> > > @@ -2357,49 +2044,14 @@ build_agf_agfl(
> > >  	}
> > >  
> > >  	freelist = xfs_buf_to_agfl_bno(agfl_buf);
> > > +	i = 0;
> > >  
> > > -	/*
> > > -	 * 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. */
> > > +	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);
> > > @@ -2497,8 +2149,8 @@ phase5_func(
> > >  	uint64_t		num_free_inos;
> > >  	uint64_t		finobt_num_inos;
> > >  	uint64_t		finobt_num_free_inos;
> > > -	bt_status_t		bno_btree_curs;
> > > -	bt_status_t		bcnt_btree_curs;
> > > +	struct bt_rebuild	btr_bno;
> > > +	struct bt_rebuild	btr_cnt;
> > >  	bt_status_t		ino_btree_curs;
> > >  	bt_status_t		fino_btree_curs;
> > >  	bt_status_t		rmap_btree_curs;
> > > @@ -2506,9 +2158,7 @@ phase5_func(
> > >  	int			extra_blocks = 0;
> > >  	uint			num_freeblocks;
> > >  	xfs_extlen_t		freeblks1;
> > > -#ifdef DEBUG
> > >  	xfs_extlen_t		freeblks2;
> > > -#endif
> > >  	xfs_agblock_t		num_extents;
> > >  
> > >  	if (verbose)
> > > @@ -2517,7 +2167,7 @@ phase5_func(
> > >  	/*
> > >  	 * build up incore bno and bcnt extent btrees
> > >  	 */
> > > -	num_extents = mk_incore_fstree(mp, agno);
> > > +	num_extents = mk_incore_fstree(mp, agno, &num_freeblocks);
> > >  
> > >  #ifdef XR_BLD_FREE_TRACE
> > >  	fprintf(stderr, "# of bno extents is %d\n",
> > > @@ -2596,8 +2246,8 @@ phase5_func(
> > >  	/*
> > >  	 * track blocks that we might really lose
> > >  	 */
> > > -	extra_blocks = calculate_freespace_cursor(mp, agno,
> > > -				&num_extents, &bno_btree_curs);
> > > +	init_freespace_cursors(&sc, agno, num_freeblocks, &num_extents,
> > > +			&extra_blocks, &btr_bno, &btr_cnt);
> > >  
> > >  	/*
> > >  	 * freespace btrees live in the "free space" but
> > > @@ -2615,13 +2265,6 @@ phase5_func(
> > >  	if (extra_blocks > 0)
> > >  		sb_fdblocks_ag[agno] -= extra_blocks;
> > >  
> > > -	bcnt_btree_curs = bno_btree_curs;
> > > -
> > > -	bno_btree_curs.owner = XFS_RMAP_OWN_AG;
> > > -	bcnt_btree_curs.owner = XFS_RMAP_OWN_AG;
> > > -	setup_cursor(mp, agno, &bno_btree_curs);
> > > -	setup_cursor(mp, agno, &bcnt_btree_curs);
> > > -
> > >  #ifdef XR_BLD_FREE_TRACE
> > >  	fprintf(stderr, "# of bno extents is %d\n",
> > >  			count_bno_extents(agno));
> > > @@ -2629,25 +2272,13 @@ phase5_func(
> > >  			count_bcnt_extents(agno));
> > >  #endif
> > >  
> > > -	/*
> > > -	 * now rebuild the freespace trees
> > > -	 */
> > > -	freeblks1 = build_freespace_tree(mp, agno,
> > > -				&bno_btree_curs, XFS_BTNUM_BNO);
> > > +	/* Rebuild the freespace btrees. */
> > > +	build_bnobt(&sc, agno, &btr_bno, &freeblks1);
> > > +	build_cntbt(&sc, agno, &btr_cnt, &freeblks2);
> > > +
> > >  #ifdef XR_BLD_FREE_TRACE
> > > -	fprintf(stderr, "# of free blocks == %d\n", freeblks1);
> > > -#endif
> > > -	write_cursor(&bno_btree_curs);
> > > -
> > > -#ifdef DEBUG
> > > -	freeblks2 = build_freespace_tree(mp, agno,
> > > -				&bcnt_btree_curs, XFS_BTNUM_CNT);
> > > -#else
> > > -	(void) build_freespace_tree(mp, agno,
> > > -				&bcnt_btree_curs, XFS_BTNUM_CNT);
> > > +	fprintf(stderr, "# of free blocks == %d/%d\n", freeblks1, freeblks2);
> > >  #endif
> > > -	write_cursor(&bcnt_btree_curs);
> > > -
> > >  	ASSERT(freeblks1 == freeblks2);
> > >  
> > >  	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
> > > @@ -2665,9 +2296,9 @@ phase5_func(
> > >  	/*
> > >  	 * set up agf and agfl
> > >  	 */
> > > -	build_agf_agfl(mp, agno, &bno_btree_curs,
> > > -			&bcnt_btree_curs, freeblks1, extra_blocks,
> > > +	build_agf_agfl(mp, agno, &btr_bno, &btr_cnt, freeblks1, extra_blocks,
> > >  			&rmap_btree_curs, &refcnt_btree_curs, lost_fsb);
> > > +
> > >  	/*
> > >  	 * build inode allocation tree.
> > >  	 */
> > > @@ -2691,15 +2322,14 @@ phase5_func(
> > >  	/*
> > >  	 * tear down cursors
> > >  	 */
> > > -	finish_cursor(&bno_btree_curs);
> > > -	finish_cursor(&ino_btree_curs);
> > > +	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
> > > 
> > 
>

Patch
diff mbox series

diff --git a/libxfs/libxfs_api_defs.h b/libxfs/libxfs_api_defs.h
index 61047f8f..bace739c 100644
--- a/libxfs/libxfs_api_defs.h
+++ b/libxfs/libxfs_api_defs.h
@@ -24,6 +24,7 @@ 
 
 #define xfs_alloc_ag_max_usable		libxfs_alloc_ag_max_usable
 #define xfs_allocbt_maxrecs		libxfs_allocbt_maxrecs
+#define xfs_allocbt_stage_cursor	libxfs_allocbt_stage_cursor
 #define xfs_alloc_fix_freelist		libxfs_alloc_fix_freelist
 #define xfs_alloc_min_freelist		libxfs_alloc_min_freelist
 #define xfs_alloc_read_agf		libxfs_alloc_read_agf
@@ -41,6 +42,8 @@ 
 #define xfs_bmbt_maxrecs		libxfs_bmbt_maxrecs
 #define xfs_bmdr_maxrecs		libxfs_bmdr_maxrecs
 
+#define xfs_btree_bload			libxfs_btree_bload
+#define xfs_btree_bload_compute_geometry libxfs_btree_bload_compute_geometry
 #define xfs_btree_del_cursor		libxfs_btree_del_cursor
 #define xfs_btree_init_block		libxfs_btree_init_block
 #define xfs_buf_delwri_submit		libxfs_buf_delwri_submit
diff --git a/repair/phase5.c b/repair/phase5.c
index 7eb24519..94e4610c 100644
--- a/repair/phase5.c
+++ b/repair/phase5.c
@@ -80,6 +80,10 @@  struct bt_rebuild {
 	/* Tree-specific data. */
 	union {
 		struct xfs_slab_cursor	*slab_cursor;
+		struct {
+			struct extent_tree_node	*bno_rec;
+			xfs_agblock_t		*freeblks;
+		};
 	};
 };
 
@@ -97,7 +101,10 @@  static uint64_t	*sb_ifree_ag;		/* free inodes per ag */
 static uint64_t	*sb_fdblocks_ag;	/* free data blocks per ag */
 
 static int
-mk_incore_fstree(xfs_mount_t *mp, xfs_agnumber_t agno)
+mk_incore_fstree(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		agno,
+	unsigned int		*num_freeblocks)
 {
 	int			in_extent;
 	int			num_extents;
@@ -109,6 +116,8 @@  mk_incore_fstree(xfs_mount_t *mp, xfs_agnumber_t agno)
 	xfs_extlen_t		blen;
 	int			bstate;
 
+	*num_freeblocks = 0;
+
 	/*
 	 * scan the bitmap for the ag looking for continuous
 	 * extents of free blocks.  At this point, we know
@@ -164,6 +173,7 @@  mk_incore_fstree(xfs_mount_t *mp, xfs_agnumber_t agno)
 #endif
 				add_bno_extent(agno, extent_start, extent_len);
 				add_bcnt_extent(agno, extent_start, extent_len);
+				*num_freeblocks += extent_len;
 			}
 		}
 	}
@@ -177,6 +187,7 @@  mk_incore_fstree(xfs_mount_t *mp, xfs_agnumber_t agno)
 #endif
 		add_bno_extent(agno, extent_start, extent_len);
 		add_bcnt_extent(agno, extent_start, extent_len);
+		*num_freeblocks += extent_len;
 	}
 
 	return(num_extents);
@@ -465,7 +476,7 @@  _("error - not enough free space in filesystem\n"));
 
 /* Feed one of the new btree blocks to the bulk loader. */
 static int
-rebuild_alloc_block(
+rebuild_claim_block(
 	struct xfs_btree_cur	*cur,
 	union xfs_btree_ptr	*ptr,
 	void			*priv)
@@ -505,313 +516,32 @@  finish_cursor(bt_status_t *curs)
 	free(curs->btree_blocks);
 }
 
+/*
+ * Scoop up leftovers from a rebuild cursor for later freeing, then free the
+ * rebuild context.
+ */
 static void
 finish_rebuild(
 	struct xfs_mount	*mp,
-	struct bt_rebuild	*btr)
+	struct bt_rebuild	*btr,
+	struct xfs_slab		*lost_fsb)
 {
 	struct xrep_newbt_resv	*resv, *n;
 
 	for_each_xrep_newbt_reservation(&btr->newbt, resv, n) {
-		xfs_agnumber_t	agno;
-		xfs_agblock_t	bno;
-		xfs_extlen_t	len;
-
-		if (resv->used >= resv->len)
-			continue;
-
-		/* XXX: Shouldn't this go on the AGFL? */
-		/* Put back everything we didn't use. */
-		bno = XFS_FSB_TO_AGBNO(mp, resv->fsbno + resv->used);
-		agno = XFS_FSB_TO_AGNO(mp, resv->fsbno + resv->used);
-		len = resv->len - resv->used;
-
-		add_bno_extent(agno, bno, len);
-		add_bcnt_extent(agno, bno, len);
-	}
-
-	xrep_newbt_destroy(&btr->newbt, 0);
-}
-
-/*
- * We need to leave some free records in the tree for the corner case of
- * setting up the AGFL. This may require allocation of blocks, and as
- * such can require insertion of new records into the tree (e.g. moving
- * a record in the by-count tree when a long extent is shortened). If we
- * pack the records into the leaves with no slack space, this requires a
- * leaf split to occur and a block to be allocated from the free list.
- * If we don't have any blocks on the free list (because we are setting
- * it up!), then we fail, and the filesystem will fail with the same
- * failure at runtime. Hence leave a couple of records slack space in
- * each block to allow immediate modification of the tree without
- * requiring splits to be done.
- *
- * XXX(hch): any reason we don't just look at mp->m_alloc_mxr?
- */
-#define XR_ALLOC_BLOCK_MAXRECS(mp, level) \
-	(libxfs_allocbt_maxrecs((mp), (mp)->m_sb.sb_blocksize, (level) == 0) - 2)
-
-/*
- * this calculates a freespace cursor for an ag.
- * btree_curs is an in/out.  returns the number of
- * blocks that will show up in the AGFL.
- */
-static int
-calculate_freespace_cursor(xfs_mount_t *mp, xfs_agnumber_t agno,
-			xfs_agblock_t *extents, bt_status_t *btree_curs)
-{
-	xfs_extlen_t		blocks_needed;		/* a running count */
-	xfs_extlen_t		blocks_allocated_pt;	/* per tree */
-	xfs_extlen_t		blocks_allocated_total;	/* for both trees */
-	xfs_agblock_t		num_extents;
-	int			i;
-	int			extents_used;
-	int			extra_blocks;
-	bt_stat_level_t		*lptr;
-	bt_stat_level_t		*p_lptr;
-	extent_tree_node_t	*ext_ptr;
-	int			level;
-
-	num_extents = *extents;
-	extents_used = 0;
-
-	ASSERT(num_extents != 0);
-
-	lptr = &btree_curs->level[0];
-	btree_curs->init = 1;
+		while (resv->used < resv->len) {
+			xfs_fsblock_t	fsb = resv->fsbno + resv->used;
+			int		error;
 
-	/*
-	 * figure out how much space we need for the leaf level
-	 * of the tree and set up the cursor for the leaf level
-	 * (note that the same code is duplicated further down)
-	 */
-	lptr->num_blocks = howmany(num_extents, XR_ALLOC_BLOCK_MAXRECS(mp, 0));
-	lptr->num_recs_pb = num_extents / lptr->num_blocks;
-	lptr->modulo = num_extents % lptr->num_blocks;
-	lptr->num_recs_tot = num_extents;
-	level = 1;
-
-#ifdef XR_BLD_FREE_TRACE
-	fprintf(stderr, "%s 0 %d %d %d %d\n", __func__,
-			lptr->num_blocks,
-			lptr->num_recs_pb,
-			lptr->modulo,
-			lptr->num_recs_tot);
-#endif
-	/*
-	 * if we need more levels, set them up.  # of records
-	 * per level is the # of blocks in the level below it
-	 */
-	if (lptr->num_blocks > 1)  {
-		for (; btree_curs->level[level - 1].num_blocks > 1
-				&& level < XFS_BTREE_MAXLEVELS;
-				level++)  {
-			lptr = &btree_curs->level[level];
-			p_lptr = &btree_curs->level[level - 1];
-			lptr->num_blocks = howmany(p_lptr->num_blocks,
-					XR_ALLOC_BLOCK_MAXRECS(mp, level));
-			lptr->modulo = p_lptr->num_blocks
-					% lptr->num_blocks;
-			lptr->num_recs_pb = p_lptr->num_blocks
-					/ lptr->num_blocks;
-			lptr->num_recs_tot = p_lptr->num_blocks;
-#ifdef XR_BLD_FREE_TRACE
-			fprintf(stderr, "%s %d %d %d %d %d\n", __func__,
-					level,
-					lptr->num_blocks,
-					lptr->num_recs_pb,
-					lptr->modulo,
-					lptr->num_recs_tot);
-#endif
-		}
-	}
-
-	ASSERT(lptr->num_blocks == 1);
-	btree_curs->num_levels = level;
-
-	/*
-	 * ok, now we have a hypothetical cursor that
-	 * will work for both the bno and bcnt trees.
-	 * now figure out if using up blocks to set up the
-	 * trees will perturb the shape of the freespace tree.
-	 * if so, we've over-allocated.  the freespace trees
-	 * as they will be *after* accounting for the free space
-	 * we've used up will need fewer blocks to to represent
-	 * than we've allocated.  We can use the AGFL to hold
-	 * xfs_agfl_size (sector/struct xfs_agfl) blocks but that's it.
-	 * Thus we limit things to xfs_agfl_size/2 for each of the 2 btrees.
-	 * if the number of extra blocks is more than that,
-	 * we'll have to be called again.
-	 */
-	for (blocks_needed = 0, i = 0; i < level; i++)  {
-		blocks_needed += btree_curs->level[i].num_blocks;
-	}
-
-	/*
-	 * record the # of blocks we've allocated
-	 */
-	blocks_allocated_pt = blocks_needed;
-	blocks_needed *= 2;
-	blocks_allocated_total = blocks_needed;
-
-	/*
-	 * figure out how many free extents will be used up by
-	 * our space allocation
-	 */
-	if ((ext_ptr = findfirst_bcnt_extent(agno)) == NULL)
-		do_error(_("can't rebuild fs trees -- not enough free space "
-			   "on ag %u\n"), agno);
-
-	while (ext_ptr != NULL && blocks_needed > 0)  {
-		if (ext_ptr->ex_blockcount <= blocks_needed)  {
-			blocks_needed -= ext_ptr->ex_blockcount;
-			extents_used++;
-		} else  {
-			blocks_needed = 0;
-		}
-
-		ext_ptr = findnext_bcnt_extent(agno, ext_ptr);
-
-#ifdef XR_BLD_FREE_TRACE
-		if (ext_ptr != NULL)  {
-			fprintf(stderr, "got next extent [%u %u]\n",
-				ext_ptr->ex_startblock, ext_ptr->ex_blockcount);
-		} else  {
-			fprintf(stderr, "out of extents\n");
-		}
-#endif
-	}
-	if (blocks_needed > 0)
-		do_error(_("ag %u - not enough free space to build freespace "
-			   "btrees\n"), agno);
-
-	ASSERT(num_extents >= extents_used);
-
-	num_extents -= extents_used;
-
-	/*
-	 * see if the number of leaf blocks will change as a result
-	 * of the number of extents changing
-	 */
-	if (howmany(num_extents, XR_ALLOC_BLOCK_MAXRECS(mp, 0))
-			!= btree_curs->level[0].num_blocks)  {
-		/*
-		 * yes -- recalculate the cursor.  If the number of
-		 * excess (overallocated) blocks is < xfs_agfl_size/2, we're ok.
-		 * we can put those into the AGFL.  we don't try
-		 * and get things to converge exactly (reach a
-		 * state with zero excess blocks) because there
-		 * exist pathological cases which will never
-		 * converge.  first, check for the zero-case.
-		 */
-		if (num_extents == 0)  {
-			/*
-			 * ok, we've used up all the free blocks
-			 * trying to lay out the leaf level. go
-			 * to a one block (empty) btree and put the
-			 * already allocated blocks into the AGFL
-			 */
-			if (btree_curs->level[0].num_blocks != 1)  {
-				/*
-				 * we really needed more blocks because
-				 * the old tree had more than one level.
-				 * this is bad.
-				 */
-				 do_warn(_("not enough free blocks left to "
-					   "describe all free blocks in AG "
-					   "%u\n"), agno);
-			}
-#ifdef XR_BLD_FREE_TRACE
-			fprintf(stderr,
-				"ag %u -- no free extents, alloc'ed %d\n",
-				agno, blocks_allocated_pt);
-#endif
-			lptr->num_blocks = 1;
-			lptr->modulo = 0;
-			lptr->num_recs_pb = 0;
-			lptr->num_recs_tot = 0;
-
-			btree_curs->num_levels = 1;
-
-			/*
-			 * don't reset the allocation stats, assume
-			 * they're all extra blocks
-			 * don't forget to return the total block count
-			 * not the per-tree block count.  these are the
-			 * extras that will go into the AGFL.  subtract
-			 * two for the root blocks.
-			 */
-			btree_curs->num_tot_blocks = blocks_allocated_pt;
-			btree_curs->num_free_blocks = blocks_allocated_pt;
-
-			*extents = 0;
-
-			return(blocks_allocated_total - 2);
-		}
-
-		lptr = &btree_curs->level[0];
-		lptr->num_blocks = howmany(num_extents,
-					XR_ALLOC_BLOCK_MAXRECS(mp, 0));
-		lptr->num_recs_pb = num_extents / lptr->num_blocks;
-		lptr->modulo = num_extents % lptr->num_blocks;
-		lptr->num_recs_tot = num_extents;
-		level = 1;
-
-		/*
-		 * if we need more levels, set them up
-		 */
-		if (lptr->num_blocks > 1)  {
-			for (level = 1; btree_curs->level[level-1].num_blocks
-					> 1 && level < XFS_BTREE_MAXLEVELS;
-					level++)  {
-				lptr = &btree_curs->level[level];
-				p_lptr = &btree_curs->level[level-1];
-				lptr->num_blocks = howmany(p_lptr->num_blocks,
-					XR_ALLOC_BLOCK_MAXRECS(mp, level));
-				lptr->modulo = p_lptr->num_blocks
-						% lptr->num_blocks;
-				lptr->num_recs_pb = p_lptr->num_blocks
-						/ lptr->num_blocks;
-				lptr->num_recs_tot = p_lptr->num_blocks;
-			}
-		}
-		ASSERT(lptr->num_blocks == 1);
-		btree_curs->num_levels = level;
-
-		/*
-		 * now figure out the number of excess blocks
-		 */
-		for (blocks_needed = 0, i = 0; i < level; i++)  {
-			blocks_needed += btree_curs->level[i].num_blocks;
-		}
-		blocks_needed *= 2;
-
-		ASSERT(blocks_allocated_total >= blocks_needed);
-		extra_blocks = blocks_allocated_total - blocks_needed;
-	} else  {
-		if (extents_used > 0) {
-			/*
-			 * reset the leaf level geometry to account
-			 * for consumed extents.  we can leave the
-			 * rest of the cursor alone since the number
-			 * of leaf blocks hasn't changed.
-			 */
-			lptr = &btree_curs->level[0];
-
-			lptr->num_recs_pb = num_extents / lptr->num_blocks;
-			lptr->modulo = num_extents % lptr->num_blocks;
-			lptr->num_recs_tot = num_extents;
+			error = slab_add(lost_fsb, &fsb);
+			if (error)
+				do_error(
+_("Insufficient memory saving lost blocks.\n"));
+			resv->used++;
 		}
-
-		extra_blocks = 0;
 	}
 
-	btree_curs->num_tot_blocks = blocks_allocated_pt;
-	btree_curs->num_free_blocks = blocks_allocated_pt;
-
-	*extents = num_extents;
-
-	return(extra_blocks);
+	xrep_newbt_destroy(&btr->newbt, 0);
 }
 
 /* Map btnum to buffer ops for the types that need it. */
@@ -838,268 +568,202 @@  btnum_to_ops(
 	}
 }
 
+/*
+ * Free Space Btrees
+ *
+ * We need to leave some free records in the tree for the corner case of
+ * setting up the AGFL. This may require allocation of blocks, and as
+ * such can require insertion of new records into the tree (e.g. moving
+ * a record in the by-count tree when a long extent is shortened). If we
+ * pack the records into the leaves with no slack space, this requires a
+ * leaf split to occur and a block to be allocated from the free list.
+ * If we don't have any blocks on the free list (because we are setting
+ * it up!), then we fail, and the filesystem will fail with the same
+ * failure at runtime. Hence leave a couple of records slack space in
+ * each block to allow immediate modification of the tree without
+ * requiring splits to be done.
+ */
+
 static void
-prop_freespace_cursor(xfs_mount_t *mp, xfs_agnumber_t agno,
-		bt_status_t *btree_curs, xfs_agblock_t startblock,
-		xfs_extlen_t blockcount, int level, xfs_btnum_t btnum)
+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)
 {
-	struct xfs_btree_block	*bt_hdr;
-	xfs_alloc_key_t		*bt_key;
-	xfs_alloc_ptr_t		*bt_ptr;
-	xfs_agblock_t		agbno;
-	bt_stat_level_t		*lptr;
-	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);
+	init_rebuild(sc, &XFS_RMAP_OINFO_AG, free_space, btr_bno);
+	init_rebuild(sc, &XFS_RMAP_OINFO_AG, free_space, btr_cnt);
 
-	level++;
-
-	if (level >= btree_curs->num_levels)
-		return;
-
-	lptr = &btree_curs->level[level];
-	bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
-
-	if (be16_to_cpu(bt_hdr->bb_numrecs) == 0)  {
-		/*
-		 * only happens once when initializing the
-		 * left-hand side of the tree.
-		 */
-		prop_freespace_cursor(mp, agno, btree_curs, startblock,
-				blockcount, level, btnum);
-	}
+	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);
 
-	if (be16_to_cpu(bt_hdr->bb_numrecs) ==
-				lptr->num_recs_pb + (lptr->modulo > 0))  {
-		/*
-		 * write out current prev block, grab us a new block,
-		 * and set the rightsib pointer of current block
-		 */
-#ifdef XR_BLD_FREE_TRACE
-		fprintf(stderr, " %d ", lptr->prev_agbno);
-#endif
-		if (lptr->prev_agbno != NULLAGBLOCK) {
-			ASSERT(lptr->prev_buf_p != NULL);
-			libxfs_buf_mark_dirty(lptr->prev_buf_p);
-			libxfs_buf_relse(lptr->prev_buf_p);
-		}
-		lptr->prev_agbno = lptr->agbno;;
-		lptr->prev_buf_p = lptr->buf_p;
-		agbno = get_next_blockaddr(agno, level, btree_curs);
+	/*
+	 * 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.
+	 */
+	do {
+		unsigned int	num_freeblocks;
 
-		bt_hdr->bb_u.s.bb_rightsib = cpu_to_be32(agbno);
+		bno_blocks = btr_bno->bload.nr_blocks;
+		cnt_blocks = btr_cnt->bload.nr_blocks;
 
-		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(
-	_("Cannot grab free space btree buffer, err=%d"),
-					error);
-		lptr->agbno = agbno;
+_("Unable to compute free space by block btree geometry, error %d.\n"), -error);
 
-		if (lptr->modulo)
-			lptr->modulo--;
-
-		/*
-		 * initialize block header
-		 */
-		lptr->buf_p->b_ops = ops;
-		bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
-		memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
-		libxfs_btree_init_block(mp, lptr->buf_p, btnum, level,
-					0, agno);
+		/* Compute how many cntbt blocks we'll need. */
+		error = -libxfs_btree_bload_compute_geometry(btr_bno->cur,
+				&btr_cnt->bload, *nr_extents);
+		if (error)
+			do_error(
+_("Unable to compute free space by length btree geometry, error %d.\n"), -error);
 
-		bt_hdr->bb_u.s.bb_leftsib = cpu_to_be32(lptr->prev_agbno);
+		/* 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;
 
-		/*
-		 * propagate extent record for first extent in new block up
-		 */
-		prop_freespace_cursor(mp, agno, btree_curs, startblock,
-				blockcount, level, btnum);
-	}
-	/*
-	 * add extent info to current block
-	 */
-	be16_add_cpu(&bt_hdr->bb_numrecs, 1);
+		/* 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);
 
-	bt_key = XFS_ALLOC_KEY_ADDR(mp, bt_hdr,
-				be16_to_cpu(bt_hdr->bb_numrecs));
-	bt_ptr = XFS_ALLOC_PTR_ADDR(mp, bt_hdr,
-				be16_to_cpu(bt_hdr->bb_numrecs),
-				mp->m_alloc_mxr[1]);
+		/* Ok, now how many free space records do we have? */
+		*nr_extents = count_bno_extents_blocks(agno, &num_freeblocks);
+	} while (1);
 
-	bt_key->ar_startblock = cpu_to_be32(startblock);
-	bt_key->ar_blockcount = cpu_to_be32(blockcount);
-	*bt_ptr = cpu_to_be32(btree_curs->level[level-1].agbno);
+	*extra_blocks = (bno_blocks - btr_bno->bload.nr_blocks) +
+			(cnt_blocks - btr_cnt->bload.nr_blocks);
 }
 
-/*
- * rebuilds a freespace tree given a cursor and type
- * of tree to build (bno or bcnt).  returns the number of free blocks
- * represented by the tree.
- */
-static xfs_extlen_t
-build_freespace_tree(xfs_mount_t *mp, xfs_agnumber_t agno,
-		bt_status_t *btree_curs, xfs_btnum_t btnum)
+static void
+get_freesp_data(
+	struct xfs_btree_cur		*cur,
+	struct extent_tree_node		*bno_rec,
+	xfs_agblock_t			*freeblks)
 {
-	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);
-	int			error;
+	struct xfs_alloc_rec_incore	*arec = &cur->bc_rec.a;
 
-	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;
+	arec->ar_startblock = bno_rec->ex_startblock;
+	arec->ar_blockcount = bno_rec->ex_blockcount;
+	if (freeblks)
+		*freeblks += bno_rec->ex_blockcount;
+}
 
-	ASSERT(level > 0);
+/* Grab one bnobt record. */
+static int
+get_bnobt_record(
+	struct xfs_btree_cur		*cur,
+	void				*priv)
+{
+	struct bt_rebuild		*btr = priv;
 
-	/*
-	 * initialize the first block on each btree level
-	 */
-	for (i = 0; i < level; i++)  {
-		lptr = &btree_curs->level[i];
+	get_freesp_data(cur, btr->bno_rec, btr->freeblks);
+	btr->bno_rec = findnext_bno_extent(btr->bno_rec);
+	return 0;
+}
 
-		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);
-		if (error)
-			do_error(
-	_("Cannot grab free space btree buffer, err=%d"),
-					error);
+/* 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;
 
-		if (i == btree_curs->num_levels - 1)
-			btree_curs->root = agbno;
+	*freeblks = 0;
+	btr_bno->bload.get_record = get_bnobt_record;
+	btr_bno->bload.claim_block = rebuild_claim_block;
+	btr_bno->bno_rec = findfirst_bno_extent(agno);
+	btr_bno->freeblks = freeblks;
 
-		lptr->agbno = agbno;
-		lptr->prev_agbno = NULLAGBLOCK;
-		lptr->prev_buf_p = NULL;
-		/*
-		 * initialize block header
-		 */
-		lptr->buf_p->b_ops = ops;
-		bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
-		memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
-		libxfs_btree_init_block(mp, lptr->buf_p, btnum, i, 0, agno);
-	}
-	/*
-	 * run along leaf, setting up records.  as we have to switch
-	 * blocks, call the prop_freespace_cursor routine to set up the new
-	 * pointers for the parent.  that can recurse up to the root
-	 * if required.  set the sibling pointers for leaf level here.
-	 */
-	if (btnum == XFS_BTNUM_BNO)
-		ext_ptr = findfirst_bno_extent(agno);
-	else
-		ext_ptr = findfirst_bcnt_extent(agno);
+	error = -libxfs_trans_alloc_empty(sc->mp, &sc->tp);
+	if (error)
+		do_error(
+_("Insufficient memory to construct bnobt rebuild transaction.\n"));
 
-#ifdef XR_BLD_FREE_TRACE
-	fprintf(stderr, "bft, agno = %d, start = %u, count = %u\n",
-		agno, ext_ptr->ex_startblock, ext_ptr->ex_blockcount);
-#endif
+	/* 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);
 
-	lptr = &btree_curs->level[0];
+	/* 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;
+}
 
-	for (i = 0; i < btree_curs->level[0].num_blocks; i++)  {
-		/*
-		 * block initialization, lay in block header
-		 */
-		lptr->buf_p->b_ops = ops;
-		bt_hdr = XFS_BUF_TO_BLOCK(lptr->buf_p);
-		memset(bt_hdr, 0, mp->m_sb.sb_blocksize);
-		libxfs_btree_init_block(mp, lptr->buf_p, btnum, 0, 0, agno);
+/* Grab one cntbt record. */
+static int
+get_cntbt_record(
+	struct xfs_btree_cur		*cur,
+	void				*priv)
+{
+	struct bt_rebuild		*btr = priv;
 
-		bt_hdr->bb_u.s.bb_leftsib = cpu_to_be32(lptr->prev_agbno);
-		bt_hdr->bb_numrecs = cpu_to_be16(lptr->num_recs_pb +
-							(lptr->modulo > 0));
-#ifdef XR_BLD_FREE_TRACE
-		fprintf(stderr, "bft, bb_numrecs = %d\n",
-				be16_to_cpu(bt_hdr->bb_numrecs));
-#endif
+	get_freesp_data(cur, btr->bno_rec, btr->freeblks);
+	btr->bno_rec = findnext_bcnt_extent(cur->bc_ag.agno, btr->bno_rec);
+	return 0;
+}
 
-		if (lptr->modulo > 0)
-			lptr->modulo--;
+/* Rebuild a freespace by count btree. */
+static void
+build_cntbt(
+	struct repair_ctx	*sc,
+	xfs_agnumber_t		agno,
+	struct bt_rebuild	*btr_cnt,
+	xfs_agblock_t		*freeblks)
+{
+	int			error;
 
-		/*
-		 * initialize values in the path up to the root if
-		 * this is a multi-level btree
-		 */
-		if (btree_curs->num_levels > 1)
-			prop_freespace_cursor(mp, agno, btree_curs,
-					ext_ptr->ex_startblock,
-					ext_ptr->ex_blockcount,
-					0, btnum);
-
-		bt_rec = (xfs_alloc_rec_t *)
-			  ((char *)bt_hdr + XFS_ALLOC_BLOCK_LEN(mp));
-		for (j = 0; j < be16_to_cpu(bt_hdr->bb_numrecs); j++) {
-			ASSERT(ext_ptr != NULL);
-			bt_rec[j].ar_startblock = cpu_to_be32(
-							ext_ptr->ex_startblock);
-			bt_rec[j].ar_blockcount = cpu_to_be32(
-							ext_ptr->ex_blockcount);
-			freeblks += ext_ptr->ex_blockcount;
-			if (btnum == XFS_BTNUM_BNO)
-				ext_ptr = findnext_bno_extent(ext_ptr);
-			else
-				ext_ptr = findnext_bcnt_extent(agno, ext_ptr);
-#if 0
-#ifdef XR_BLD_FREE_TRACE
-			if (ext_ptr == NULL)
-				fprintf(stderr, "null extent pointer, j = %d\n",
-					j);
-			else
-				fprintf(stderr,
-				"bft, agno = %d, start = %u, count = %u\n",
-					agno, ext_ptr->ex_startblock,
-					ext_ptr->ex_blockcount);
-#endif
-#endif
-		}
+	*freeblks = 0;
+	btr_cnt->bload.get_record = get_cntbt_record;
+	btr_cnt->bload.claim_block = rebuild_claim_block;
+	btr_cnt->bno_rec = findfirst_bcnt_extent(agno);
+	btr_cnt->freeblks = freeblks;
 
-		if (ext_ptr != NULL)  {
-			/*
-			 * get next leaf level block
-			 */
-			if (lptr->prev_buf_p != NULL)  {
-#ifdef XR_BLD_FREE_TRACE
-				fprintf(stderr, " writing fst agbno %u\n",
-					lptr->prev_agbno);
-#endif
-				ASSERT(lptr->prev_agbno != NULLAGBLOCK);
-				libxfs_buf_mark_dirty(lptr->prev_buf_p);
-				libxfs_buf_relse(lptr->prev_buf_p);
-			}
-			lptr->prev_buf_p = lptr->buf_p;
-			lptr->prev_agbno = lptr->agbno;
-			lptr->agbno = get_next_blockaddr(agno, 0, btree_curs);
-			bt_hdr->bb_u.s.bb_rightsib = cpu_to_be32(lptr->agbno);
+	error = -libxfs_trans_alloc_empty(sc->mp, &sc->tp);
+	if (error)
+		do_error(
+_("Insufficient memory to construct cntbt rebuild transaction.\n"));
 
-			error = -libxfs_buf_get(mp->m_dev,
-					XFS_AGB_TO_DADDR(mp, agno, lptr->agbno),
-					XFS_FSB_TO_BB(mp, 1),
-					&lptr->buf_p);
-			if (error)
-				do_error(
-	_("Cannot grab free space btree buffer, err=%d"),
-						error);
-		}
-	}
+	/* Add all observed cntbt records. */
+	error = -libxfs_btree_bload(btr_cnt->cur, &btr_cnt->bload, btr_cnt);
+	if (error)
+		do_error(
+_("Error %d while creating cntbt btree for AG %u.\n"), error, agno);
 
-	return(freeblks);
+	/* Since we're not writing the AGF yet, no need to commit the cursor */
+	libxfs_btree_del_cursor(btr_cnt->cur, 0);
+	error = -libxfs_trans_commit(sc->tp);
+	if (error)
+		do_error(
+_("Error %d while writing cntbt btree for AG %u.\n"), error, agno);
+	sc->tp = NULL;
 }
 
 /*
@@ -2233,6 +1897,27 @@  _("Insufficient memory to construct refcount cursor."));
 	free_slab_cursor(&refc_cur);
 }
 
+/* Fill the AGFL with any leftover bnobt rebuilder blocks. */
+static void
+fill_agfl(
+	struct bt_rebuild	*btr,
+	__be32			*agfl_bnos,
+	int			*i)
+{
+	struct xrep_newbt_resv	*resv, *n;
+	struct xfs_mount	*mp = btr->newbt.sc->mp;
+
+	for_each_xrep_newbt_reservation(&btr->newbt, resv, n) {
+		xfs_agblock_t	bno;
+
+		bno = XFS_FSB_TO_AGBNO(mp, resv->fsbno + resv->used);
+		while (resv->used < resv->len && (*i) < libxfs_agfl_size(mp)) {
+			agfl_bnos[(*i)++] = cpu_to_be32(bno++);
+			resv->used++;
+		}
+	}
+}
+
 /*
  * build both the agf and the agfl for an agno given both
  * btree cursors.
@@ -2243,8 +1928,8 @@  static void
 build_agf_agfl(
 	struct xfs_mount	*mp,
 	xfs_agnumber_t		agno,
-	struct bt_status	*bno_bt,
-	struct bt_status	*bcnt_bt,
+	struct bt_rebuild	*btr_bno,
+	struct bt_rebuild	*btr_cnt,
 	xfs_extlen_t		freeblks,	/* # free blocks in tree */
 	int			lostblocks,	/* # blocks that will be lost */
 	struct bt_status	*rmap_bt,
@@ -2256,7 +1941,6 @@  build_agf_agfl(
 	int			i;
 	struct xfs_agfl		*agfl;
 	struct xfs_agf		*agf;
-	xfs_fsblock_t		fsb;
 	__be32			*freelist;
 	int			error;
 
@@ -2288,10 +1972,14 @@  build_agf_agfl(
 		agf->agf_length = cpu_to_be32(mp->m_sb.sb_dblocks -
 			(xfs_rfsblock_t) mp->m_sb.sb_agblocks * agno);
 
-	agf->agf_roots[XFS_BTNUM_BNO] = cpu_to_be32(bno_bt->root);
-	agf->agf_levels[XFS_BTNUM_BNO] = cpu_to_be32(bno_bt->num_levels);
-	agf->agf_roots[XFS_BTNUM_CNT] = cpu_to_be32(bcnt_bt->root);
-	agf->agf_levels[XFS_BTNUM_CNT] = cpu_to_be32(bcnt_bt->num_levels);
+	agf->agf_roots[XFS_BTNUM_BNO] =
+			cpu_to_be32(btr_bno->newbt.afake.af_root);
+	agf->agf_levels[XFS_BTNUM_BNO] =
+			cpu_to_be32(btr_bno->newbt.afake.af_levels);
+	agf->agf_roots[XFS_BTNUM_CNT] =
+			cpu_to_be32(btr_cnt->newbt.afake.af_root);
+	agf->agf_levels[XFS_BTNUM_CNT] =
+			cpu_to_be32(btr_cnt->newbt.afake.af_levels);
 	agf->agf_roots[XFS_BTNUM_RMAP] = cpu_to_be32(rmap_bt->root);
 	agf->agf_levels[XFS_BTNUM_RMAP] = cpu_to_be32(rmap_bt->num_levels);
 	agf->agf_freeblks = cpu_to_be32(freeblks);
@@ -2311,9 +1999,8 @@  build_agf_agfl(
 		 * Don't count the root blocks as they are already
 		 * accounted for.
 		 */
-		blks = (bno_bt->num_tot_blocks - bno_bt->num_free_blocks) +
-			(bcnt_bt->num_tot_blocks - bcnt_bt->num_free_blocks) -
-			2;
+		blks = btr_bno->newbt.afake.af_blocks +
+			btr_cnt->newbt.afake.af_blocks - 2;
 		if (xfs_sb_version_hasrmapbt(&mp->m_sb))
 			blks += rmap_bt->num_tot_blocks - rmap_bt->num_free_blocks - 1;
 		agf->agf_btreeblks = cpu_to_be32(blks);
@@ -2357,49 +2044,14 @@  build_agf_agfl(
 	}
 
 	freelist = xfs_buf_to_agfl_bno(agfl_buf);
+	i = 0;
 
-	/*
-	 * 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. */
+	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);
@@ -2497,8 +2149,8 @@  phase5_func(
 	uint64_t		num_free_inos;
 	uint64_t		finobt_num_inos;
 	uint64_t		finobt_num_free_inos;
-	bt_status_t		bno_btree_curs;
-	bt_status_t		bcnt_btree_curs;
+	struct bt_rebuild	btr_bno;
+	struct bt_rebuild	btr_cnt;
 	bt_status_t		ino_btree_curs;
 	bt_status_t		fino_btree_curs;
 	bt_status_t		rmap_btree_curs;
@@ -2506,9 +2158,7 @@  phase5_func(
 	int			extra_blocks = 0;
 	uint			num_freeblocks;
 	xfs_extlen_t		freeblks1;
-#ifdef DEBUG
 	xfs_extlen_t		freeblks2;
-#endif
 	xfs_agblock_t		num_extents;
 
 	if (verbose)
@@ -2517,7 +2167,7 @@  phase5_func(
 	/*
 	 * build up incore bno and bcnt extent btrees
 	 */
-	num_extents = mk_incore_fstree(mp, agno);
+	num_extents = mk_incore_fstree(mp, agno, &num_freeblocks);
 
 #ifdef XR_BLD_FREE_TRACE
 	fprintf(stderr, "# of bno extents is %d\n",
@@ -2596,8 +2246,8 @@  phase5_func(
 	/*
 	 * track blocks that we might really lose
 	 */
-	extra_blocks = calculate_freespace_cursor(mp, agno,
-				&num_extents, &bno_btree_curs);
+	init_freespace_cursors(&sc, agno, num_freeblocks, &num_extents,
+			&extra_blocks, &btr_bno, &btr_cnt);
 
 	/*
 	 * freespace btrees live in the "free space" but
@@ -2615,13 +2265,6 @@  phase5_func(
 	if (extra_blocks > 0)
 		sb_fdblocks_ag[agno] -= extra_blocks;
 
-	bcnt_btree_curs = bno_btree_curs;
-
-	bno_btree_curs.owner = XFS_RMAP_OWN_AG;
-	bcnt_btree_curs.owner = XFS_RMAP_OWN_AG;
-	setup_cursor(mp, agno, &bno_btree_curs);
-	setup_cursor(mp, agno, &bcnt_btree_curs);
-
 #ifdef XR_BLD_FREE_TRACE
 	fprintf(stderr, "# of bno extents is %d\n",
 			count_bno_extents(agno));
@@ -2629,25 +2272,13 @@  phase5_func(
 			count_bcnt_extents(agno));
 #endif
 
-	/*
-	 * now rebuild the freespace trees
-	 */
-	freeblks1 = build_freespace_tree(mp, agno,
-				&bno_btree_curs, XFS_BTNUM_BNO);
+	/* Rebuild the freespace btrees. */
+	build_bnobt(&sc, agno, &btr_bno, &freeblks1);
+	build_cntbt(&sc, agno, &btr_cnt, &freeblks2);
+
 #ifdef XR_BLD_FREE_TRACE
-	fprintf(stderr, "# of free blocks == %d\n", freeblks1);
-#endif
-	write_cursor(&bno_btree_curs);
-
-#ifdef DEBUG
-	freeblks2 = build_freespace_tree(mp, agno,
-				&bcnt_btree_curs, XFS_BTNUM_CNT);
-#else
-	(void) build_freespace_tree(mp, agno,
-				&bcnt_btree_curs, XFS_BTNUM_CNT);
+	fprintf(stderr, "# of free blocks == %d/%d\n", freeblks1, freeblks2);
 #endif
-	write_cursor(&bcnt_btree_curs);
-
 	ASSERT(freeblks1 == freeblks2);
 
 	if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
@@ -2665,9 +2296,9 @@  phase5_func(
 	/*
 	 * set up agf and agfl
 	 */
-	build_agf_agfl(mp, agno, &bno_btree_curs,
-			&bcnt_btree_curs, freeblks1, extra_blocks,
+	build_agf_agfl(mp, agno, &btr_bno, &btr_cnt, freeblks1, extra_blocks,
 			&rmap_btree_curs, &refcnt_btree_curs, lost_fsb);
+
 	/*
 	 * build inode allocation tree.
 	 */
@@ -2691,15 +2322,14 @@  phase5_func(
 	/*
 	 * tear down cursors
 	 */
-	finish_cursor(&bno_btree_curs);
-	finish_cursor(&ino_btree_curs);
+	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