On 7/2/20 10:18 AM, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> Create some new support structures and functions to assist phase5 in
> using the btree bulk loader to reconstruct metadata btrees. This is the
> first step in removing the open-coded AG btree rebuilding code.
>
> Note: The code in this patch will not be used anywhere until the next
> patch, so warnings about unused symbols are expected.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> v2: set the "nearly out of space" slack value to 2 so that we don't
> start out with tons of btree splitting right after mount
Reviewed-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Not sure if Brian's RVB carries through the V2 change or not ...
> ---
> repair/Makefile | 4 +
> repair/agbtree.c | 152 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> repair/agbtree.h | 29 ++++++++++
> repair/bulkload.c | 41 ++++++++++++++
> repair/bulkload.h | 2 +
> 5 files changed, 226 insertions(+), 2 deletions(-)
> create mode 100644 repair/agbtree.c
> create mode 100644 repair/agbtree.h
>
> diff --git a/repair/Makefile b/repair/Makefile
> index 62d84bbf..f6a6e3f9 100644
> --- a/repair/Makefile
> +++ b/repair/Makefile
> @@ -9,11 +9,11 @@ LSRCFILES = README
>
> LTCOMMAND = xfs_repair
>
> -HFILES = agheader.h attr_repair.h avl.h bulkload.h bmap.h btree.h \
> +HFILES = agheader.h agbtree.h attr_repair.h avl.h bulkload.h bmap.h btree.h \
> da_util.h dinode.h dir2.h err_protos.h globals.h incore.h protos.h \
> rt.h progress.h scan.h versions.h prefetch.h rmap.h slab.h threads.h
>
> -CFILES = agheader.c attr_repair.c avl.c bulkload.c bmap.c btree.c \
> +CFILES = agheader.c agbtree.c attr_repair.c avl.c bulkload.c bmap.c btree.c \
> da_util.c dino_chunks.c dinode.c dir2.c globals.c incore.c \
> incore_bmc.c init.c incore_ext.c incore_ino.c phase1.c \
> phase2.c phase3.c phase4.c phase5.c phase6.c phase7.c \
> diff --git a/repair/agbtree.c b/repair/agbtree.c
> new file mode 100644
> index 00000000..95a3eac9
> --- /dev/null
> +++ b/repair/agbtree.c
> @@ -0,0 +1,152 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2020 Oracle. All Rights Reserved.
> + * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> + */
> +#include <libxfs.h>
> +#include "err_protos.h"
> +#include "slab.h"
> +#include "rmap.h"
> +#include "incore.h"
> +#include "bulkload.h"
> +#include "agbtree.h"
> +
> +/* Initialize a btree rebuild context. */
> +static void
> +init_rebuild(
> + struct repair_ctx *sc,
> + const struct xfs_owner_info *oinfo,
> + xfs_agblock_t free_space,
> + struct bt_rebuild *btr)
> +{
> + memset(btr, 0, sizeof(struct bt_rebuild));
> +
> + bulkload_init_ag(&btr->newbt, sc, oinfo);
> + bulkload_estimate_ag_slack(sc, &btr->bload, free_space);
> +}
> +
> +/*
> + * Update this free space record to reflect the blocks we stole from the
> + * beginning of the record.
> + */
> +static void
> +consume_freespace(
> + xfs_agnumber_t agno,
> + struct extent_tree_node *ext_ptr,
> + uint32_t len)
> +{
> + struct extent_tree_node *bno_ext_ptr;
> + xfs_agblock_t new_start = ext_ptr->ex_startblock + len;
> + xfs_extlen_t new_len = ext_ptr->ex_blockcount - len;
> +
> + /* Delete the used-up extent from both extent trees. */
> +#ifdef XR_BLD_FREE_TRACE
> + fprintf(stderr, "releasing extent: %u [%u %u]\n", agno,
> + ext_ptr->ex_startblock, ext_ptr->ex_blockcount);
> +#endif
> + bno_ext_ptr = find_bno_extent(agno, ext_ptr->ex_startblock);
> + ASSERT(bno_ext_ptr != NULL);
> + get_bno_extent(agno, bno_ext_ptr);
> + release_extent_tree_node(bno_ext_ptr);
> +
> + ext_ptr = get_bcnt_extent(agno, ext_ptr->ex_startblock,
> + ext_ptr->ex_blockcount);
> + release_extent_tree_node(ext_ptr);
> +
> + /*
> + * If we only used part of this last extent, then we must reinsert the
> + * extent to maintain proper sorting order.
> + */
> + if (new_len > 0) {
> + add_bno_extent(agno, new_start, new_len);
> + add_bcnt_extent(agno, new_start, new_len);
> + }
> +}
> +
> +/* Reserve blocks for the new per-AG structures. */
> +static void
> +reserve_btblocks(
> + struct xfs_mount *mp,
> + xfs_agnumber_t agno,
> + struct bt_rebuild *btr,
> + uint32_t nr_blocks)
> +{
> + struct extent_tree_node *ext_ptr;
> + uint32_t blocks_allocated = 0;
> + uint32_t len;
> + int error;
> +
> + while (blocks_allocated < nr_blocks) {
> + xfs_fsblock_t fsbno;
> +
> + /*
> + * Grab the smallest extent and use it up, then get the
> + * next smallest. This mimics the init_*_cursor code.
> + */
> + ext_ptr = findfirst_bcnt_extent(agno);
> + if (!ext_ptr)
> + do_error(
> +_("error - not enough free space in filesystem\n"));
> +
> + /* Use up the extent we've got. */
> + len = min(ext_ptr->ex_blockcount, nr_blocks - blocks_allocated);
> + fsbno = XFS_AGB_TO_FSB(mp, agno, ext_ptr->ex_startblock);
> + error = bulkload_add_blocks(&btr->newbt, fsbno, len);
> + if (error)
> + do_error(_("could not set up btree reservation: %s\n"),
> + strerror(-error));
> +
> + error = rmap_add_ag_rec(mp, agno, ext_ptr->ex_startblock, len,
> + btr->newbt.oinfo.oi_owner);
> + if (error)
> + do_error(_("could not set up btree rmaps: %s\n"),
> + strerror(-error));
> +
> + consume_freespace(agno, ext_ptr, len);
> + blocks_allocated += len;
> + }
> +#ifdef XR_BLD_FREE_TRACE
> + fprintf(stderr, "blocks_allocated = %d\n",
> + blocks_allocated);
> +#endif
> +}
> +
> +/* Feed one of the new btree blocks to the bulk loader. */
> +static int
> +rebuild_claim_block(
> + struct xfs_btree_cur *cur,
> + union xfs_btree_ptr *ptr,
> + void *priv)
> +{
> + struct bt_rebuild *btr = priv;
> +
> + return bulkload_claim_block(cur, &btr->newbt, ptr);
> +}
> +
> +/*
> + * Scoop up leftovers from a rebuild cursor for later freeing, then free the
> + * rebuild context.
> + */
> +void
> +finish_rebuild(
> + struct xfs_mount *mp,
> + struct bt_rebuild *btr,
> + struct xfs_slab *lost_fsb)
> +{
> + struct bulkload_resv *resv, *n;
> +
> + for_each_bulkload_reservation(&btr->newbt, resv, n) {
> + while (resv->used < resv->len) {
> + xfs_fsblock_t fsb = resv->fsbno + resv->used;
> + int error;
> +
> + error = slab_add(lost_fsb, &fsb);
> + if (error)
> + do_error(
> +_("Insufficient memory saving lost blocks.\n"));
> + resv->used++;
> + }
> + }
> +
> + bulkload_destroy(&btr->newbt, 0);
> +}
> diff --git a/repair/agbtree.h b/repair/agbtree.h
> new file mode 100644
> index 00000000..50ea3c60
> --- /dev/null
> +++ b/repair/agbtree.h
> @@ -0,0 +1,29 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright (C) 2020 Oracle. All Rights Reserved.
> + * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> + */
> +#ifndef __XFS_REPAIR_AG_BTREE_H__
> +#define __XFS_REPAIR_AG_BTREE_H__
> +
> +/* Context for rebuilding a per-AG btree. */
> +struct bt_rebuild {
> + /* Fake root for staging and space preallocations. */
> + struct bulkload newbt;
> +
> + /* Geometry of the new btree. */
> + struct xfs_btree_bload bload;
> +
> + /* Staging btree cursor for the new tree. */
> + struct xfs_btree_cur *cur;
> +
> + /* Tree-specific data. */
> + union {
> + struct xfs_slab_cursor *slab_cursor;
> + };
> +};
> +
> +void finish_rebuild(struct xfs_mount *mp, struct bt_rebuild *btr,
> + struct xfs_slab *lost_fsb);
> +
> +#endif /* __XFS_REPAIR_AG_BTREE_H__ */
> diff --git a/repair/bulkload.c b/repair/bulkload.c
> index 4c69fe0d..81d67e62 100644
> --- a/repair/bulkload.c
> +++ b/repair/bulkload.c
> @@ -95,3 +95,44 @@ bulkload_claim_block(
> ptr->s = cpu_to_be32(XFS_FSB_TO_AGBNO(cur->bc_mp, fsb));
> return 0;
> }
> +
> +/*
> + * Estimate proper slack values for a btree that's being reloaded.
> + *
> + * Under most circumstances, we'll take whatever default loading value the
> + * btree bulk loading code calculates for us. However, there are some
> + * exceptions to this rule:
> + *
> + * (1) If someone turned one of the debug knobs.
> + * (2) The AG has less than ~9% space free.
> + *
> + * Note that we actually use 3/32 for the comparison to avoid division.
> + */
> +void
> +bulkload_estimate_ag_slack(
> + struct repair_ctx *sc,
> + struct xfs_btree_bload *bload,
> + unsigned int free)
> +{
> + /*
> + * The global values are set to -1 (i.e. take the bload defaults)
> + * unless someone has set them otherwise, so we just pull the values
> + * here.
> + */
> + bload->leaf_slack = bload_leaf_slack;
> + bload->node_slack = bload_node_slack;
> +
> + /* No further changes if there's more than 3/32ths space left. */
> + if (free >= ((sc->mp->m_sb.sb_agblocks * 3) >> 5))
> + return;
> +
> + /*
> + * We're low on space; load the btrees as tightly as possible. Leave
> + * a couple of open slots in each btree block so that we don't end up
> + * splitting the btrees like crazy right after mount.
> + */
> + if (bload->leaf_slack < 0)
> + bload->leaf_slack = 2;
> + if (bload->node_slack < 0)
> + bload->node_slack = 2;
> +}
> diff --git a/repair/bulkload.h b/repair/bulkload.h
> index 79f81cb0..01f67279 100644
> --- a/repair/bulkload.h
> +++ b/repair/bulkload.h
> @@ -53,5 +53,7 @@ int bulkload_add_blocks(struct bulkload *bkl, xfs_fsblock_t fsbno,
> void bulkload_destroy(struct bulkload *bkl, int error);
> int bulkload_claim_block(struct xfs_btree_cur *cur, struct bulkload *bkl,
> union xfs_btree_ptr *ptr);
> +void bulkload_estimate_ag_slack(struct repair_ctx *sc,
> + struct xfs_btree_bload *bload, unsigned int free);
>
> #endif /* __XFS_REPAIR_BULKLOAD_H__ */
>
