Re: [PATCH 07/21] xfs: repair inode btrees

[Allison Henderson <allison.henderson@oracle.com>]

On 06/24/2018 12:24 PM, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Use the rmapbt to find inode chunks, query the chunks to compute
> hole and free masks, and with that information rebuild the inobt
> and finobt.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>   fs/xfs/Makefile              |    1
>   fs/xfs/scrub/ialloc_repair.c |  585 ++++++++++++++++++++++++++++++++++++++++++
>   fs/xfs/scrub/repair.h        |    2
>   fs/xfs/scrub/scrub.c         |    4
>   4 files changed, 590 insertions(+), 2 deletions(-)
>   create mode 100644 fs/xfs/scrub/ialloc_repair.c
> 
> 
> diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
> index 841e0824eeb6..837fd4a95f6f 100644
> --- a/fs/xfs/Makefile
> +++ b/fs/xfs/Makefile
> @@ -165,6 +165,7 @@ ifeq ($(CONFIG_XFS_ONLINE_REPAIR),y)
>   xfs-y				+= $(addprefix scrub/, \
>   				   agheader_repair.o \
>   				   alloc_repair.o \
> +				   ialloc_repair.o \
>   				   repair.o \
>   				   )
>   endif
> diff --git a/fs/xfs/scrub/ialloc_repair.c b/fs/xfs/scrub/ialloc_repair.c
> new file mode 100644
> index 000000000000..29c736466bba
> --- /dev/null
> +++ b/fs/xfs/scrub/ialloc_repair.c
> @@ -0,0 +1,585 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2018 Oracle.  All Rights Reserved.
> + * Author: Darrick J. Wong <darrick.wong@oracle.com>
> + */
> +#include "xfs.h"
> +#include "xfs_fs.h"
> +#include "xfs_shared.h"
> +#include "xfs_format.h"
> +#include "xfs_trans_resv.h"
> +#include "xfs_mount.h"
> +#include "xfs_defer.h"
> +#include "xfs_btree.h"
> +#include "xfs_bit.h"
> +#include "xfs_log_format.h"
> +#include "xfs_trans.h"
> +#include "xfs_sb.h"
> +#include "xfs_inode.h"
> +#include "xfs_alloc.h"
> +#include "xfs_ialloc.h"
> +#include "xfs_ialloc_btree.h"
> +#include "xfs_icache.h"
> +#include "xfs_rmap.h"
> +#include "xfs_rmap_btree.h"
> +#include "xfs_log.h"
> +#include "xfs_trans_priv.h"
> +#include "xfs_error.h"
> +#include "scrub/xfs_scrub.h"
> +#include "scrub/scrub.h"
> +#include "scrub/common.h"
> +#include "scrub/btree.h"
> +#include "scrub/trace.h"
> +#include "scrub/repair.h"
> +
> +/*
> + * Inode Btree Repair
> + * ==================
> + *
> + * Iterate the reverse mapping records looking for OWN_INODES and OWN_INOBT
> + * records.  The OWN_INOBT records are the old inode btree blocks and will be
> + * cleared out after we've rebuilt the tree.  Each possible inode chunk within
> + * an OWN_INODES record will be read in and the freemask calculated from the
> + * i_mode data in the inode chunk.  For sparse inodes the holemask will be
> + * calculated by creating the properly aligned inobt record and punching out
> + * any chunk that's missing.  Inode allocations and frees grab the AGI first,
> + * so repair protects itself from concurrent access by locking the AGI.
> + *
> + * Once we've reconstructed all the inode records, we can create new inode
> + * btree roots and reload the btrees.  We rebuild both inode trees at the same
> + * time because they have the same rmap owner and it would be more complex to
> + * figure out if the other tree isn't in need of a rebuild and which OWN_INOBT
> + * blocks it owns.  We have all the data we need to build both, so dump
> + * everything and start over.
> + */
> +
> +struct xfs_repair_ialloc_extent {
> +	struct list_head		list;
> +	xfs_inofree_t			freemask;
> +	xfs_agino_t			startino;
> +	unsigned int			count;
> +	unsigned int			usedcount;
> +	uint16_t			holemask;
> +};
> +
> +struct xfs_repair_ialloc {
> +	struct list_head		*extlist;
> +	struct xfs_repair_extent_list	*btlist;
> +	struct xfs_scrub_context	*sc;
> +	uint64_t			nr_records;
> +};
> +
> +/*
> + * Is this inode in use?  If the inode is in memory we can tell from i_mode,
> + * otherwise we have to check di_mode in the on-disk buffer.  We only care
> + * that the high (i.e. non-permission) bits of _mode are zero.  This should be
> + * safe because repair keeps all AG headers locked until the end, and process
> + * trying to perform an inode allocation/free must lock the AGI.
> + */
> +STATIC int
> +xfs_repair_ialloc_check_free(
> +	struct xfs_scrub_context	*sc,
> +	struct xfs_buf			*bp,
> +	xfs_ino_t			fsino,
> +	xfs_agino_t			bpino,
> +	bool				*inuse)
> +{
> +	struct xfs_mount		*mp = sc->mp;
> +	struct xfs_dinode		*dip;
> +	int				error;
> +
> +	/* Will the in-core inode tell us if it's in use? */
> +	error = xfs_icache_inode_is_allocated(mp, sc->tp, fsino, inuse);
> +	if (!error)
> +		return 0;
> +
> +	/* Inode uncached or half assembled, read disk buffer */
> +	dip = xfs_buf_offset(bp, bpino * mp->m_sb.sb_inodesize);
> +	if (be16_to_cpu(dip->di_magic) != XFS_DINODE_MAGIC)
> +		return -EFSCORRUPTED;
> +
> +	if (dip->di_version >= 3 && be64_to_cpu(dip->di_ino) != fsino)
> +		return -EFSCORRUPTED;
> +
> +	*inuse = dip->di_mode != 0;
> +	return 0;
> +}
> +
> +/*
> + * For each cluster in this blob of inode, we must calculate the
Ok, so I've been over this one a few times, and I still don't feel
like I've figured out what a blob of an inode is. So I'm gonna have
to break and ask for clarification on that one?  Thx! :-)

> + * properly aligned startino of that cluster, then iterate each
> + * cluster to fill in used and filled masks appropriately.  We
> + * then use the (startino, used, filled) information to construct
> + * the appropriate inode records.
> + */
> +STATIC int
> +xfs_repair_ialloc_process_cluster(
> +	struct xfs_repair_ialloc	*ri,
> +	xfs_agblock_t			agbno,
> +	int				blks_per_cluster,
> +	xfs_agino_t			rec_agino)
> +{
> +	struct xfs_imap			imap;
> +	struct xfs_repair_ialloc_extent	*rie;
> +	struct xfs_dinode		*dip;
> +	struct xfs_buf			*bp;
> +	struct xfs_scrub_context	*sc = ri->sc;
> +	struct xfs_mount		*mp = sc->mp;
> +	xfs_ino_t			fsino;
> +	xfs_inofree_t			usedmask;
> +	xfs_agino_t			nr_inodes;
> +	xfs_agino_t			startino;
> +	xfs_agino_t			clusterino;
> +	xfs_agino_t			clusteroff;
> +	xfs_agino_t			agino;
> +	uint16_t			fillmask;
> +	bool				inuse;
> +	int				usedcount;
> +	int				error;
> +
> +	/* The per-AG inum of this inode cluster. */
> +	agino = XFS_OFFBNO_TO_AGINO(mp, agbno, 0);
> +
> +	/* The per-AG inum of the inobt record. */
> +	startino = rec_agino + rounddown(agino - rec_agino,
> +			XFS_INODES_PER_CHUNK);
> +
> +	/* The per-AG inum of the cluster within the inobt record. */
> +	clusteroff = agino - startino;
> +
> +	/* Every inode in this holemask slot is filled. */
> +	nr_inodes = XFS_OFFBNO_TO_AGINO(mp, blks_per_cluster, 0);
> +	fillmask = xfs_inobt_maskn(clusteroff / XFS_INODES_PER_HOLEMASK_BIT,
> +			nr_inodes / XFS_INODES_PER_HOLEMASK_BIT);
> +
> +	/* Grab the inode cluster buffer. */
> +	imap.im_blkno = XFS_AGB_TO_DADDR(mp, sc->sa.agno, agbno);
> +	imap.im_len = XFS_FSB_TO_BB(mp, blks_per_cluster);
> +	imap.im_boffset = 0;
> +
> +	error = xfs_imap_to_bp(mp, sc->tp, &imap, &dip, &bp, 0,
> +			XFS_IGET_UNTRUSTED);
> +	if (error)
> +		return error;
> +
> +	usedmask = 0;
> +	usedcount = 0;
> +	/* Which inodes within this cluster are free? */
> +	for (clusterino = 0; clusterino < nr_inodes; clusterino++) {
> +		fsino = XFS_AGINO_TO_INO(mp, sc->sa.agno, agino + clusterino);
> +		error = xfs_repair_ialloc_check_free(sc, bp, fsino,
> +				clusterino, &inuse);
> +		if (error) {
> +			xfs_trans_brelse(sc->tp, bp);
> +			return error;
> +		}
> +		if (inuse) {
> +			usedcount++;
> +			usedmask |= XFS_INOBT_MASK(clusteroff + clusterino);
> +		}
> +	}
> +	xfs_trans_brelse(sc->tp, bp);
> +
> +	/*
> +	 * If the last item in the list is our chunk record,
> +	 * update that.
> +	 */
> +	if (!list_empty(ri->extlist)) {
> +		rie = list_last_entry(ri->extlist,
> +				struct xfs_repair_ialloc_extent, list);
> +		if (rie->startino + XFS_INODES_PER_CHUNK > startino) {
> +			rie->freemask &= ~usedmask;
> +			rie->holemask &= ~fillmask;
> +			rie->count += nr_inodes;
> +			rie->usedcount += usedcount;
> +			return 0;
> +		}
> +	}
> +
> +	/* New inode chunk; add to the list. */
> +	rie = kmem_alloc(sizeof(struct xfs_repair_ialloc_extent), KM_MAYFAIL);
> +	if (!rie)
> +		return -ENOMEM;
> +
> +	INIT_LIST_HEAD(&rie->list);
> +	rie->startino = startino;
> +	rie->freemask = XFS_INOBT_ALL_FREE & ~usedmask;
> +	rie->holemask = XFS_INOBT_ALL_FREE & ~fillmask;
> +	rie->count = nr_inodes;
> +	rie->usedcount = usedcount;
> +	list_add_tail(&rie->list, ri->extlist);
> +	ri->nr_records++;
> +
> +	return 0;
> +}
> +
> +/* Record extents that belong to inode btrees. */
> +STATIC int
> +xfs_repair_ialloc_extent_fn(
> +	struct xfs_btree_cur		*cur,
> +	struct xfs_rmap_irec		*rec,
> +	void				*priv)
> +{
> +	struct xfs_repair_ialloc	*ri = priv;
> +	struct xfs_mount		*mp = cur->bc_mp;
> +	xfs_fsblock_t			fsbno;
> +	xfs_agblock_t			agbno = rec->rm_startblock;
> +	xfs_agino_t			inoalign;
> +	xfs_agino_t			agino;
> +	xfs_agino_t			rec_agino;
> +	int				blks_per_cluster;
> +	int				error = 0;
> +
> +	if (xfs_scrub_should_terminate(ri->sc, &error))
> +		return error;
> +
> +	/* Fragment of the old btrees; dispose of them later. */
> +	if (rec->rm_owner == XFS_RMAP_OWN_INOBT) {
> +		fsbno = XFS_AGB_TO_FSB(mp, ri->sc->sa.agno, agbno);
> +		return xfs_repair_collect_btree_extent(ri->sc, ri->btlist,
> +				fsbno, rec->rm_blockcount);
> +	}
> +
> +	/* Skip extents which are not owned by this inode and fork. */
> +	if (rec->rm_owner != XFS_RMAP_OWN_INODES)
> +		return 0;
> +
> +	blks_per_cluster = xfs_icluster_size_fsb(mp);
> +
> +	if (agbno % blks_per_cluster != 0)
> +		return -EFSCORRUPTED;
> +
> +	trace_xfs_repair_ialloc_extent_fn(mp, ri->sc->sa.agno,
> +			rec->rm_startblock, rec->rm_blockcount, rec->rm_owner,
> +			rec->rm_offset, rec->rm_flags);
> +
> +	/*
> +	 * Determine the inode block alignment, and where the block
> +	 * ought to start if it's aligned properly.  On a sparse inode
> +	 * system the rmap doesn't have to start on an alignment boundary,
> +	 * but the record does.  On pre-sparse filesystems, we /must/
> +	 * start both rmap and inobt on an alignment boundary.
> +	 */
> +	inoalign = xfs_ialloc_cluster_alignment(mp);
> +	agino = XFS_OFFBNO_TO_AGINO(mp, agbno, 0);
> +	rec_agino = XFS_OFFBNO_TO_AGINO(mp, rounddown(agbno, inoalign), 0);
> +	if (!xfs_sb_version_hassparseinodes(&mp->m_sb) && agino != rec_agino)
> +		return -EFSCORRUPTED;
> +
> +	/* Set up the free/hole masks for each cluster in this inode chunk. */
By chunk you did you mean record?  Please try to keep terminology
consistent as best you can.  Thx! :-)

> +	for (;
> +	     agbno < rec->rm_startblock + rec->rm_blockcount;
> +	     agbno += blks_per_cluster) {
> +		error = xfs_repair_ialloc_process_cluster(ri, agbno,
> +				blks_per_cluster, rec_agino);
> +		if (error)
> +			return error;
> +	}
> +
> +	return 0;
> +}
> +
> +/* Compare two ialloc extents. */
> +static int
> +xfs_repair_ialloc_extent_cmp(
> +	void				*priv,
> +	struct list_head		*a,
> +	struct list_head		*b)
> +{
> +	struct xfs_repair_ialloc_extent	*ap;
> +	struct xfs_repair_ialloc_extent	*bp;
> +
> +	ap = container_of(a, struct xfs_repair_ialloc_extent, list);
> +	bp = container_of(b, struct xfs_repair_ialloc_extent, list);
> +
> +	if (ap->startino > bp->startino)
> +		return 1;
> +	else if (ap->startino < bp->startino)
> +		return -1;
> +	return 0;
> +}
> +
> +/* Insert an inode chunk record into a given btree. */
> +static int
> +xfs_repair_iallocbt_insert_btrec(
> +	struct xfs_btree_cur		*cur,
> +	struct xfs_repair_ialloc_extent	*rie)
> +{
> +	int				stat;
> +	int				error;
> +
> +	error = xfs_inobt_lookup(cur, rie->startino, XFS_LOOKUP_EQ, &stat);
> +	if (error)
> +		return error;
> +	XFS_WANT_CORRUPTED_RETURN(cur->bc_mp, stat == 0);
> +	error = xfs_inobt_insert_rec(cur, rie->holemask, rie->count,
> +			rie->count - rie->usedcount, rie->freemask, &stat);
> +	if (error)
> +		return error;
> +	XFS_WANT_CORRUPTED_RETURN(cur->bc_mp, stat == 1);
> +	return error;
> +}
> +
> +/* Insert an inode chunk record into both inode btrees. */
> +static int
> +xfs_repair_iallocbt_insert_rec(
> +	struct xfs_scrub_context	*sc,
> +	struct xfs_repair_ialloc_extent	*rie)
> +{
> +	struct xfs_btree_cur		*cur;
> +	int				error;
> +
> +	trace_xfs_repair_ialloc_insert(sc->mp, sc->sa.agno, rie->startino,
> +			rie->holemask, rie->count, rie->count - rie->usedcount,
> +			rie->freemask);
> +
> +	/* Insert into the inobt. */
> +	cur = xfs_inobt_init_cursor(sc->mp, sc->tp, sc->sa.agi_bp, sc->sa.agno,
> +			XFS_BTNUM_INO);
> +	error = xfs_repair_iallocbt_insert_btrec(cur, rie);
> +	if (error)
> +		goto out_cur;
> +	xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
> +
> +	/* Insert into the finobt if chunk has free inodes. */
> +	if (xfs_sb_version_hasfinobt(&sc->mp->m_sb) &&
> +	    rie->count != rie->usedcount) {
> +		cur = xfs_inobt_init_cursor(sc->mp, sc->tp, sc->sa.agi_bp,
> +				sc->sa.agno, XFS_BTNUM_FINO);
> +		error = xfs_repair_iallocbt_insert_btrec(cur, rie);
> +		if (error)
> +			goto out_cur;
> +		xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
> +	}
> +
> +	return xfs_repair_roll_ag_trans(sc);
> +out_cur:
> +	xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
> +	return error;
> +}
> +
> +/* Free every record in the inode list. */
> +STATIC void
> +xfs_repair_iallocbt_cancel_inorecs(
> +	struct list_head		*reclist)
> +{
> +	struct xfs_repair_ialloc_extent	*rie;
> +	struct xfs_repair_ialloc_extent	*n;
> +
> +	list_for_each_entry_safe(rie, n, reclist, list) {
> +		list_del(&rie->list);
> +		kmem_free(rie);
> +	}
> +}
> +
> +/*
> + * Iterate all reverse mappings to find the inodes (OWN_INODES) and the inode
> + * btrees (OWN_INOBT).  Figure out if we have enough free space to reconstruct
> + * the inode btrees.  The caller must clean up the lists if anything goes
> + * wrong.
> + */
> +STATIC int
> +xfs_repair_iallocbt_find_inodes(
> +	struct xfs_scrub_context	*sc,
> +	struct list_head		*inode_records,
> +	struct xfs_repair_extent_list	*old_iallocbt_blocks)
> +{
> +	struct xfs_repair_ialloc	ri;
> +	struct xfs_mount		*mp = sc->mp;
> +	struct xfs_btree_cur		*cur;
> +	xfs_agblock_t			nr_blocks;
> +	int				error;
> +
> +	/* Collect all reverse mappings for inode blocks. */
> +	ri.extlist = inode_records;
> +	ri.btlist = old_iallocbt_blocks;
> +	ri.nr_records = 0;
> +	ri.sc = sc;
> +
> +	cur = xfs_rmapbt_init_cursor(mp, sc->tp, sc->sa.agf_bp, sc->sa.agno);
> +	error = xfs_rmap_query_all(cur, xfs_repair_ialloc_extent_fn, &ri);
> +	if (error)
> +		goto err;
> +	xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
> +
> +	/* Do we actually have enough space to do this? */
> +	nr_blocks = xfs_iallocbt_calc_size(mp, ri.nr_records);
> +	if (xfs_sb_version_hasfinobt(&mp->m_sb))
> +		nr_blocks *= 2;
> +	if (!xfs_repair_ag_has_space(sc->sa.pag, nr_blocks, XFS_AG_RESV_NONE))
> +		return -ENOSPC;
> +
> +	return 0;
> +
> +err:
> +	xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
> +	return error;
> +}
> +
> +/* Update the AGI counters. */
> +STATIC int
> +xfs_repair_iallocbt_reset_counters(
> +	struct xfs_scrub_context	*sc,
> +	struct list_head		*inode_records,
> +	int				*log_flags)
> +{
> +	struct xfs_agi			*agi;
> +	struct xfs_repair_ialloc_extent	*rie;
> +	unsigned int			count = 0;
> +	unsigned int			usedcount = 0;
> +	unsigned int			freecount;
> +
> +	/* Figure out the new counters. */
> +	list_for_each_entry(rie, inode_records, list) {
> +		count += rie->count;
> +		usedcount += rie->usedcount;
> +	}
> +
> +	agi = XFS_BUF_TO_AGI(sc->sa.agi_bp);
> +	freecount = count - usedcount;
> +
> +	/* XXX: trigger inode count recalculation */
> +
> +	/* Reset the per-AG info, both incore and ondisk. */
> +	sc->sa.pag->pagi_count = count;
> +	sc->sa.pag->pagi_freecount = freecount;
> +	agi->agi_count = cpu_to_be32(count);
> +	agi->agi_freecount = cpu_to_be32(freecount);
> +	*log_flags |= XFS_AGI_COUNT | XFS_AGI_FREECOUNT;
> +
> +	return 0;
> +}
> +
> +/* Initialize new inobt/finobt roots and implant them into the AGI. */
> +STATIC int
> +xfs_repair_iallocbt_reset_btrees(
> +	struct xfs_scrub_context	*sc,
> +	struct xfs_owner_info		*oinfo,
> +	int				*log_flags)
> +{
> +	struct xfs_agi			*agi;
> +	struct xfs_buf			*bp;
> +	struct xfs_mount		*mp = sc->mp;
> +	xfs_fsblock_t			inofsb;
> +	xfs_fsblock_t			finofsb;
> +	enum xfs_ag_resv_type		resv;
> +	int				error;
> +
> +	agi = XFS_BUF_TO_AGI(sc->sa.agi_bp);
> +
> +	/* Initialize new inobt root. */
> +	resv = XFS_AG_RESV_NONE;
> +	error = xfs_repair_alloc_ag_block(sc, oinfo, &inofsb, resv);
> +	if (error)
> +		return error;
> +	error = xfs_repair_init_btblock(sc, inofsb, &bp, XFS_BTNUM_INO,
> +			&xfs_inobt_buf_ops);
> +	if (error)
> +		return error;
> +	agi->agi_root = cpu_to_be32(XFS_FSB_TO_AGBNO(mp, inofsb));
> +	agi->agi_level = cpu_to_be32(1);
> +	*log_flags |= XFS_AGI_ROOT | XFS_AGI_LEVEL;
> +
> +	/* Initialize new finobt root. */
> +	if (!xfs_sb_version_hasfinobt(&mp->m_sb))
> +		return 0;
> +
> +	resv = mp->m_inotbt_nores ? XFS_AG_RESV_NONE : XFS_AG_RESV_METADATA;
> +	error = xfs_repair_alloc_ag_block(sc, oinfo, &finofsb, resv);
> +	if (error)
> +		return error;
> +	error = xfs_repair_init_btblock(sc, finofsb, &bp, XFS_BTNUM_FINO,
> +			&xfs_inobt_buf_ops);
> +	if (error)
> +		return error;
> +	agi->agi_free_root = cpu_to_be32(XFS_FSB_TO_AGBNO(mp, finofsb));
> +	agi->agi_free_level = cpu_to_be32(1);
> +	*log_flags |= XFS_AGI_FREE_ROOT | XFS_AGI_FREE_LEVEL;
> +
> +	return 0;
> +}
> +
> +/* Build new inode btrees and dispose of the old one. */
> +STATIC int
> +xfs_repair_iallocbt_rebuild_trees(
> +	struct xfs_scrub_context	*sc,
> +	struct list_head		*inode_records,
> +	struct xfs_owner_info		*oinfo,
> +	struct xfs_repair_extent_list	*old_iallocbt_blocks)
> +{
> +	struct xfs_repair_ialloc_extent	*rie;
> +	struct xfs_repair_ialloc_extent	*n;
> +	int				error;
> +
> +	/* Add all records. */
> +	list_sort(NULL, inode_records, xfs_repair_ialloc_extent_cmp);
> +	list_for_each_entry_safe(rie, n, inode_records, list) {
> +		error = xfs_repair_iallocbt_insert_rec(sc, rie);
> +		if (error)
> +			return error;
> +
> +		list_del(&rie->list);
> +		kmem_free(rie);
> +	}
> +
> +	/* Free the old inode btree blocks if they're not in use. */
> +	return xfs_repair_reap_btree_extents(sc, old_iallocbt_blocks, oinfo,
> +			XFS_AG_RESV_NONE);
> +}
> +
> +/* Repair both inode btrees. */
> +int
> +xfs_repair_iallocbt(
> +	struct xfs_scrub_context	*sc)
> +{
> +	struct xfs_owner_info		oinfo;
> +	struct list_head		inode_records;
> +	struct xfs_repair_extent_list	old_iallocbt_blocks;
> +	struct xfs_mount		*mp = sc->mp;
> +	int				log_flags = 0;
> +	int				error = 0;
> +
> +	/* We require the rmapbt to rebuild anything. */
> +	if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
> +		return -EOPNOTSUPP;
> +
> +	xfs_scrub_perag_get(sc->mp, &sc->sa);
> +
> +	/* Collect the free space data and find the old btree blocks. */
> +	xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_INOBT);
> +	INIT_LIST_HEAD(&inode_records);
> +	xfs_repair_init_extent_list(&old_iallocbt_blocks);
> +	error = xfs_repair_iallocbt_find_inodes(sc, &inode_records,
> +			&old_iallocbt_blocks);
> +	if (error)
> +		goto out;
> +
> +	/*
> +	 * Blow out the old inode btrees.  This is the point at which
> +	 * we are no longer able to bail out gracefully.
> +	 */
> +	error = xfs_repair_iallocbt_reset_counters(sc, &inode_records,
> +			&log_flags);
> +	if (error)
> +		goto out;
> +	error = xfs_repair_iallocbt_reset_btrees(sc, &oinfo, &log_flags);
> +	if (error)
> +		goto out;
> +	xfs_ialloc_log_agi(sc->tp, sc->sa.agi_bp, log_flags);
> +
> +	/* Invalidate all the inobt/finobt blocks in btlist. */
> +	error = xfs_repair_invalidate_blocks(sc, &old_iallocbt_blocks);
> +	if (error)
> +		goto out;
> +	error = xfs_repair_roll_ag_trans(sc);
> +	if (error)
> +		goto out;
> +
> +	/* Now rebuild the inode information. */
> +	error = xfs_repair_iallocbt_rebuild_trees(sc, &inode_records, &oinfo,
> +			&old_iallocbt_blocks);
> +out:
> +	xfs_repair_cancel_btree_extents(sc, &old_iallocbt_blocks);
> +	xfs_repair_iallocbt_cancel_inorecs(&inode_records);
> +	return error;
> +}
> diff --git a/fs/xfs/scrub/repair.h b/fs/xfs/scrub/repair.h
> index e5f67fc68e9a..dcfa5eb18940 100644
> --- a/fs/xfs/scrub/repair.h
> +++ b/fs/xfs/scrub/repair.h
> @@ -104,6 +104,7 @@ int xfs_repair_agf(struct xfs_scrub_context *sc);
>   int xfs_repair_agfl(struct xfs_scrub_context *sc);
>   int xfs_repair_agi(struct xfs_scrub_context *sc);
>   int xfs_repair_allocbt(struct xfs_scrub_context *sc);
> +int xfs_repair_iallocbt(struct xfs_scrub_context *sc);
>   
>   #else
>   
> @@ -131,6 +132,7 @@ xfs_repair_calc_ag_resblks(
>   #define xfs_repair_agfl			xfs_repair_notsupported
>   #define xfs_repair_agi			xfs_repair_notsupported
>   #define xfs_repair_allocbt		xfs_repair_notsupported
> +#define xfs_repair_iallocbt		xfs_repair_notsupported
>   
>   #endif /* CONFIG_XFS_ONLINE_REPAIR */
>   
> diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
> index 7a55b20b7e4e..fec0e130f19e 100644
> --- a/fs/xfs/scrub/scrub.c
> +++ b/fs/xfs/scrub/scrub.c
> @@ -238,14 +238,14 @@ static const struct xfs_scrub_meta_ops meta_scrub_ops[] = {
>   		.type	= ST_PERAG,
>   		.setup	= xfs_scrub_setup_ag_iallocbt,
>   		.scrub	= xfs_scrub_inobt,
> -		.repair	= xfs_repair_notsupported,
> +		.repair	= xfs_repair_iallocbt,
>   	},
>   	[XFS_SCRUB_TYPE_FINOBT] = {	/* finobt */
>   		.type	= ST_PERAG,
>   		.setup	= xfs_scrub_setup_ag_iallocbt,
>   		.scrub	= xfs_scrub_finobt,
>   		.has	= xfs_sb_version_hasfinobt,
> -		.repair	= xfs_repair_notsupported,
> +		.repair	= xfs_repair_iallocbt,
>   	},
>   	[XFS_SCRUB_TYPE_RMAPBT] = {	/* rmapbt */
>   		.type	= ST_PERAG,
> 

Ok, some parts took some time to figure out, but I think I understand
the overall idea.  The comments help, and if you could add in a little
extra detail describing the function parameters, I think it would help
to add more supporting context to your comments.  Thx!

Allison

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