path: root/fs/xfs/scrub/agheader_repair.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2018-2023 Oracle.  All Rights Reserved.
 * Author: Darrick J. Wong <djwong@kernel.org>
 */
#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_btree.h"
#include "xfs_log_format.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_alloc.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc.h"
#include "xfs_ialloc_btree.h"
#include "xfs_rmap.h"
#include "xfs_rmap_btree.h"
#include "xfs_refcount_btree.h"
#include "xfs_ag.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
#include "scrub/repair.h"
#include "scrub/bitmap.h"
#include "scrub/agb_bitmap.h"
#include "scrub/reap.h"

/* Superblock */

/* Repair the superblock. */
int
xrep_superblock(
	struct xfs_scrub	*sc)
{
	struct xfs_mount	*mp = sc->mp;
	struct xfs_buf		*bp;
	xfs_agnumber_t		agno;
	int			error;

	/* Don't try to repair AG 0's sb; let xfs_repair deal with it. */
	agno = sc->sm->sm_agno;
	if (agno == 0)
		return -EOPNOTSUPP;

	error = xfs_sb_get_secondary(mp, sc->tp, agno, &bp);
	if (error)
		return error;

	/* Last chance to abort before we start committing fixes. */
	if (xchk_should_terminate(sc, &error))
		return error;

	/* Copy AG 0's superblock to this one. */
	xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
	xfs_sb_to_disk(bp->b_addr, &mp->m_sb);

	/*
	 * Don't write out a secondary super with NEEDSREPAIR or log incompat
	 * features set, since both are ignored when set on a secondary.
	 */
	if (xfs_has_crc(mp)) {
		struct xfs_dsb		*sb = bp->b_addr;

		sb->sb_features_incompat &=
				~cpu_to_be32(XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR);
		sb->sb_features_log_incompat = 0;
	}

	/* Write this to disk. */
	xfs_trans_buf_set_type(sc->tp, bp, XFS_BLFT_SB_BUF);
	xfs_trans_log_buf(sc->tp, bp, 0, BBTOB(bp->b_length) - 1);
	return 0;
}

/* AGF */

struct xrep_agf_allocbt {
	struct xfs_scrub	*sc;
	xfs_agblock_t		freeblks;
	xfs_agblock_t		longest;
};

/* Record free space shape information. */
STATIC int
xrep_agf_walk_allocbt(
	struct xfs_btree_cur		*cur,
	const struct xfs_alloc_rec_incore *rec,
	void				*priv)
{
	struct xrep_agf_allocbt		*raa = priv;
	int				error = 0;

	if (xchk_should_terminate(raa->sc, &error))
		return error;

	raa->freeblks += rec->ar_blockcount;
	if (rec->ar_blockcount > raa->longest)
		raa->longest = rec->ar_blockcount;
	return error;
}

/* Does this AGFL block look sane? */
STATIC int
xrep_agf_check_agfl_block(
	struct xfs_mount	*mp,
	xfs_agblock_t		agbno,
	void			*priv)
{
	struct xfs_scrub	*sc = priv;

	if (!xfs_verify_agbno(sc->sa.pag, agbno))
		return -EFSCORRUPTED;
	return 0;
}

/*
 * Offset within the xrep_find_ag_btree array for each btree type.  Avoid the
 * XFS_BTNUM_ names here to avoid creating a sparse array.
 */
enum {
	XREP_AGF_BNOBT = 0,
	XREP_AGF_CNTBT,
	XREP_AGF_RMAPBT,
	XREP_AGF_REFCOUNTBT,
	XREP_AGF_END,
	XREP_AGF_MAX
};

/* Check a btree root candidate. */
static inline bool
xrep_check_btree_root(
	struct xfs_scrub		*sc,
	struct xrep_find_ag_btree	*fab)
{
	return xfs_verify_agbno(sc->sa.pag, fab->root) &&
	       fab->height <= fab->maxlevels;
}

/*
 * Given the btree roots described by *fab, find the roots, check them for
 * sanity, and pass the root data back out via *fab.
 *
 * This is /also/ a chicken and egg problem because we have to use the rmapbt
 * (rooted in the AGF) to find the btrees rooted in the AGF.  We also have no
 * idea if the btrees make any sense.  If we hit obvious corruptions in those
 * btrees we'll bail out.
 */
STATIC int
xrep_agf_find_btrees(
	struct xfs_scrub		*sc,
	struct xfs_buf			*agf_bp,
	struct xrep_find_ag_btree	*fab,
	struct xfs_buf			*agfl_bp)
{
	struct xfs_agf			*old_agf = agf_bp->b_addr;
	int				error;

	/* Go find the root data. */
	error = xrep_find_ag_btree_roots(sc, agf_bp, fab, agfl_bp);
	if (error)
		return error;

	/* We must find the bnobt, cntbt, and rmapbt roots. */
	if (!xrep_check_btree_root(sc, &fab[XREP_AGF_BNOBT]) ||
	    !xrep_check_btree_root(sc, &fab[XREP_AGF_CNTBT]) ||
	    !xrep_check_btree_root(sc, &fab[XREP_AGF_RMAPBT]))
		return -EFSCORRUPTED;

	/*
	 * We relied on the rmapbt to reconstruct the AGF.  If we get a
	 * different root then something's seriously wrong.
	 */
	if (fab[XREP_AGF_RMAPBT].root !=
	    be32_to_cpu(old_agf->agf_roots[XFS_BTNUM_RMAPi]))
		return -EFSCORRUPTED;

	/* We must find the refcountbt root if that feature is enabled. */
	if (xfs_has_reflink(sc->mp) &&
	    !xrep_check_btree_root(sc, &fab[XREP_AGF_REFCOUNTBT]))
		return -EFSCORRUPTED;

	return 0;
}

/*
 * Reinitialize the AGF header, making an in-core copy of the old contents so
 * that we know which in-core state needs to be reinitialized.
 */
STATIC void
xrep_agf_init_header(
	struct xfs_scrub	*sc,
	struct xfs_buf		*agf_bp,
	struct xfs_agf		*old_agf)
{
	struct xfs_mount	*mp = sc->mp;
	struct xfs_perag	*pag = sc->sa.pag;
	struct xfs_agf		*agf = agf_bp->b_addr;

	memcpy(old_agf, agf, sizeof(*old_agf));
	memset(