On Fri, Jul 10, 2020 at 12:10:26PM -0700, Eric Sandeen wrote:
> 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 ...
>
No objection from me if the only changes were adjusting the default slack
values and lifting out the unrelated hunk..
Brian
> > ---
> > 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__ */
> >
>
