// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2017-2023 Oracle.  All Rights Reserved.
 * Author: Darrick J. Wong <djwong@kernel.org>
 */
#include "xfs_platform.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_sb.h"
#include "xfs_alloc.h"
#include "xfs_ialloc.h"
#include "xfs_rmap.h"
#include "xfs_ag.h"
#include "xfs_inode.h"
#include "scrub/scrub.h"
#include "scrub/common.h"

int
xchk_setup_agheader(
        struct xfs_scrub        *sc)
{
        if (xchk_need_intent_drain(sc))
                xchk_fsgates_enable(sc, XCHK_FSGATES_DRAIN);
        return xchk_setup_fs(sc);
}

/* Superblock */

/* Cross-reference with the other btrees. */
STATIC void
xchk_superblock_xref(
        struct xfs_scrub        *sc,
        struct xfs_buf          *bp)
{
        struct xfs_mount        *mp = sc->mp;
        xfs_agnumber_t          agno = sc->sm->sm_agno;
        xfs_agblock_t           agbno;
        int                     error;

        if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                return;

        agbno = XFS_SB_BLOCK(mp);

        error = xchk_ag_init_existing(sc, agno, &sc->sa);
        if (!xchk_xref_process_error(sc, agno, agbno, &error))
                return;

        xchk_xref_is_used_space(sc, agbno, 1);
        xchk_xref_is_not_inode_chunk(sc, agbno, 1);
        xchk_xref_is_only_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
        xchk_xref_is_not_shared(sc, agbno, 1);
        xchk_xref_is_not_cow_staging(sc, agbno, 1);

        /* scrub teardown will take care of sc->sa for us */
}

/*
 * Calculate the ondisk superblock size in bytes given the feature set of the
 * mounted filesystem (aka the primary sb).  This is subtlely different from
 * the logic in xfs_repair, which computes the size of a secondary sb given the
 * featureset listed in the secondary sb.
 */
STATIC size_t
xchk_superblock_ondisk_size(
        struct xfs_mount        *mp)
{
        if (xfs_has_zoned(mp))
                return offsetofend(struct xfs_dsb, sb_rtreserved);
        if (xfs_has_metadir(mp))
                return offsetofend(struct xfs_dsb, sb_pad);
        if (xfs_has_metauuid(mp))
                return offsetofend(struct xfs_dsb, sb_meta_uuid);
        if (xfs_has_crc(mp))
                return offsetofend(struct xfs_dsb, sb_lsn);
        if (xfs_sb_version_hasmorebits(&mp->m_sb))
                return offsetofend(struct xfs_dsb, sb_bad_features2);
        if (xfs_has_logv2(mp))
                return offsetofend(struct xfs_dsb, sb_logsunit);
        if (xfs_has_sector(mp))
                return offsetofend(struct xfs_dsb, sb_logsectsize);
        /* only support dirv2 or more recent */
        return offsetofend(struct xfs_dsb, sb_dirblklog);
}

/*
 * Scrub the filesystem superblock.
 *
 * Note: We do /not/ attempt to check AG 0's superblock.  Mount is
 * responsible for validating all the geometry information in sb 0, so
 * if the filesystem is capable of initiating online scrub, then clearly
 * sb 0 is ok and we can use its information to check everything else.
 */
int
xchk_superblock(
        struct xfs_scrub        *sc)
{
        struct xfs_mount        *mp = sc->mp;
        struct xfs_buf          *bp;
        struct xfs_dsb          *sb;
        struct xfs_perag        *pag;
        size_t                  sblen;
        xfs_agnumber_t          agno;
        uint32_t                v2_ok;
        __be32                  features_mask;
        int                     error;
        __be16                  vernum_mask;

        agno = sc->sm->sm_agno;
        if (agno == 0)
                return 0;

        /*
         * Grab an active reference to the perag structure.  If we can't get
         * it, we're racing with something that's tearing down the AG, so
         * signal that the AG no longer exists.
         */
        pag = xfs_perag_get(mp, agno);
        if (!pag)
                return -ENOENT;

        error = xfs_sb_read_secondary(mp, sc->tp, agno, &bp);
        /*
         * The superblock verifier can return several different error codes
         * if it thinks the superblock doesn't look right.  For a mount these
         * would all get bounced back to userspace, but if we're here then the
         * fs mounted successfully, which means that this secondary superblock
         * is simply incorrect.  Treat all these codes the same way we treat
         * any corruption.
         */
        switch (error) {
        case -EINVAL:   /* also -EWRONGFS */
        case -ENOSYS:
        case -EFBIG:
                error = -EFSCORRUPTED;
                fallthrough;
        default:
                break;
        }
        if (!xchk_process_error(sc, agno, XFS_SB_BLOCK(mp), &error))
                goto out_pag;

        sb = bp->b_addr;

        /*
         * Verify the geometries match.  Fields that are permanently
         * set by mkfs are checked; fields that can be updated later
         * (and are not propagated to backup superblocks) are preen
         * checked.
         */
        if (sb->sb_blocksize != cpu_to_be32(mp->m_sb.sb_blocksize))
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_dblocks != cpu_to_be64(mp->m_sb.sb_dblocks))
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_rblocks != cpu_to_be64(mp->m_sb.sb_rblocks))
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_rextents != cpu_to_be64(mp->m_sb.sb_rextents))
                xchk_block_set_corrupt(sc, bp);

        if (!uuid_equal(&sb->sb_uuid, &mp->m_sb.sb_uuid))
                xchk_block_set_preen(sc, bp);

        if (sb->sb_logstart != cpu_to_be64(mp->m_sb.sb_logstart))
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_rootino != cpu_to_be64(mp->m_sb.sb_rootino))
                xchk_block_set_preen(sc, bp);

        if (xfs_has_metadir(sc->mp)) {
                if (sb->sb_rbmino != cpu_to_be64(0))
                        xchk_block_set_corrupt(sc, bp);

                if (sb->sb_rsumino != cpu_to_be64(0))
                        xchk_block_set_corrupt(sc, bp);
        } else {
                if (sb->sb_rbmino != cpu_to_be64(mp->m_sb.sb_rbmino))
                        xchk_block_set_preen(sc, bp);

                if (sb->sb_rsumino != cpu_to_be64(mp->m_sb.sb_rsumino))
                        xchk_block_set_preen(sc, bp);
        }

        if (sb->sb_rextsize != cpu_to_be32(mp->m_sb.sb_rextsize))
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_agblocks != cpu_to_be32(mp->m_sb.sb_agblocks))
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_agcount != cpu_to_be32(mp->m_sb.sb_agcount))
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_rbmblocks != cpu_to_be32(mp->m_sb.sb_rbmblocks))
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_logblocks != cpu_to_be32(mp->m_sb.sb_logblocks))
                xchk_block_set_corrupt(sc, bp);

        /* Check sb_versionnum bits that are set at mkfs time. */
        vernum_mask = cpu_to_be16(XFS_SB_VERSION_NUMBITS |
                                  XFS_SB_VERSION_ALIGNBIT |
                                  XFS_SB_VERSION_DALIGNBIT |
                                  XFS_SB_VERSION_SHAREDBIT |
                                  XFS_SB_VERSION_LOGV2BIT |
                                  XFS_SB_VERSION_SECTORBIT |
                                  XFS_SB_VERSION_EXTFLGBIT |
                                  XFS_SB_VERSION_DIRV2BIT);
        if ((sb->sb_versionnum & vernum_mask) !=
            (cpu_to_be16(mp->m_sb.sb_versionnum) & vernum_mask))
                xchk_block_set_corrupt(sc, bp);

        /* Check sb_versionnum bits that can be set after mkfs time. */
        vernum_mask = cpu_to_be16(XFS_SB_VERSION_ATTRBIT |
                                  XFS_SB_VERSION_NLINKBIT |
                                  XFS_SB_VERSION_QUOTABIT);
        if ((sb->sb_versionnum & vernum_mask) !=
            (cpu_to_be16(mp->m_sb.sb_versionnum) & vernum_mask))
                xchk_block_set_preen(sc, bp);

        if (sb->sb_sectsize != cpu_to_be16(mp->m_sb.sb_sectsize))
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_inodesize != cpu_to_be16(mp->m_sb.sb_inodesize))
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_inopblock != cpu_to_be16(mp->m_sb.sb_inopblock))
                xchk_block_set_corrupt(sc, bp);

        if (memcmp(sb->sb_fname, mp->m_sb.sb_fname, sizeof(sb->sb_fname)))
                xchk_block_set_preen(sc, bp);

        if (sb->sb_blocklog != mp->m_sb.sb_blocklog)
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_sectlog != mp->m_sb.sb_sectlog)
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_inodelog != mp->m_sb.sb_inodelog)
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_inopblog != mp->m_sb.sb_inopblog)
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_agblklog != mp->m_sb.sb_agblklog)
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_rextslog != mp->m_sb.sb_rextslog)
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_imax_pct != mp->m_sb.sb_imax_pct)
                xchk_block_set_preen(sc, bp);

        /*
         * Skip the summary counters since we track them in memory anyway.
         * sb_icount, sb_ifree, sb_fdblocks, sb_frexents
         */

        if (xfs_has_metadir(mp)) {
                if (sb->sb_uquotino != cpu_to_be64(0))
                        xchk_block_set_corrupt(sc, bp);

                if (sb->sb_gquotino != cpu_to_be64(0))
                        xchk_block_set_preen(sc, bp);
        } else {
                if (sb->sb_uquotino != cpu_to_be64(mp->m_sb.sb_uquotino))
                        xchk_block_set_preen(sc, bp);

                if (sb->sb_gquotino != cpu_to_be64(mp->m_sb.sb_gquotino))
                        xchk_block_set_preen(sc, bp);
        }

        /*
         * Skip the quota flags since repair will force quotacheck.
         * sb_qflags
         */

        if (sb->sb_flags != mp->m_sb.sb_flags)
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_shared_vn != mp->m_sb.sb_shared_vn)
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_inoalignmt != cpu_to_be32(mp->m_sb.sb_inoalignmt))
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_unit != cpu_to_be32(mp->m_sb.sb_unit))
                xchk_block_set_preen(sc, bp);

        if (sb->sb_width != cpu_to_be32(mp->m_sb.sb_width))
                xchk_block_set_preen(sc, bp);

        if (sb->sb_dirblklog != mp->m_sb.sb_dirblklog)
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_logsectlog != mp->m_sb.sb_logsectlog)
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_logsectsize != cpu_to_be16(mp->m_sb.sb_logsectsize))
                xchk_block_set_corrupt(sc, bp);

        if (sb->sb_logsunit != cpu_to_be32(mp->m_sb.sb_logsunit))
                xchk_block_set_corrupt(sc, bp);

        /* Do we see any invalid bits in sb_features2? */
        if (!xfs_sb_version_hasmorebits(&mp->m_sb)) {
                if (sb->sb_features2 != 0)
                        xchk_block_set_corrupt(sc, bp);
        } else {
                v2_ok = XFS_SB_VERSION2_OKBITS;
                if (xfs_sb_is_v5(&mp->m_sb))
                        v2_ok |= XFS_SB_VERSION2_CRCBIT;

                if (!!(sb->sb_features2 & cpu_to_be32(~v2_ok)))
                        xchk_block_set_corrupt(sc, bp);

                if (sb->sb_features2 != sb->sb_bad_features2)
                        xchk_block_set_preen(sc, bp);
        }

        /* Check sb_features2 flags that are set at mkfs time. */
        features_mask = cpu_to_be32(XFS_SB_VERSION2_LAZYSBCOUNTBIT |
                                    XFS_SB_VERSION2_PROJID32BIT |
                                    XFS_SB_VERSION2_CRCBIT |
                                    XFS_SB_VERSION2_FTYPE);
        if ((sb->sb_features2 & features_mask) !=
            (cpu_to_be32(mp->m_sb.sb_features2) & features_mask))
                xchk_block_set_corrupt(sc, bp);

        /* Check sb_features2 flags that can be set after mkfs time. */
        features_mask = cpu_to_be32(XFS_SB_VERSION2_ATTR2BIT);
        if ((sb->sb_features2 & features_mask) !=
            (cpu_to_be32(mp->m_sb.sb_features2) & features_mask))
                xchk_block_set_preen(sc, bp);

        if (!xfs_has_crc(mp)) {
                /* all v5 fields must be zero */
                if (memchr_inv(&sb->sb_features_compat, 0,
                                sizeof(struct xfs_dsb) -
                                offsetof(struct xfs_dsb, sb_features_compat)))
                        xchk_block_set_corrupt(sc, bp);
        } else {
                /* compat features must match */
                if (sb->sb_features_compat !=
                                cpu_to_be32(mp->m_sb.sb_features_compat))
                        xchk_block_set_corrupt(sc, bp);

                /* ro compat features must match */
                if (sb->sb_features_ro_compat !=
                                cpu_to_be32(mp->m_sb.sb_features_ro_compat))
                        xchk_block_set_corrupt(sc, bp);

                /*
                 * NEEDSREPAIR is ignored on a secondary super, so we should
                 * clear it when we find it, though it's not a corruption.
                 */
                features_mask = cpu_to_be32(XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR);
                if ((cpu_to_be32(mp->m_sb.sb_features_incompat) ^
                                sb->sb_features_incompat) & features_mask)
                        xchk_block_set_preen(sc, bp);

                /* all other incompat features must match */
                if ((cpu_to_be32(mp->m_sb.sb_features_incompat) ^
                                sb->sb_features_incompat) & ~features_mask)
                        xchk_block_set_corrupt(sc, bp);

                /*
                 * log incompat features protect newer log record types from
                 * older log recovery code.  Log recovery doesn't check the
                 * secondary supers, so we can clear these if needed.
                 */
                if (sb->sb_features_log_incompat)
                        xchk_block_set_preen(sc, bp);

                /* Don't care about sb_crc */

                if (sb->sb_spino_align != cpu_to_be32(mp->m_sb.sb_spino_align))
                        xchk_block_set_corrupt(sc, bp);

                if (xfs_has_metadir(mp)) {
                        if (sb->sb_pquotino != cpu_to_be64(0))
                                xchk_block_set_corrupt(sc, bp);
                } else {
                        if (sb->sb_pquotino != cpu_to_be64(mp->m_sb.sb_pquotino))
                                xchk_block_set_preen(sc, bp);
                }

                /* Don't care about sb_lsn */
        }

        if (xfs_has_metauuid(mp)) {
                /* The metadata UUID must be the same for all supers */
                if (!uuid_equal(&sb->sb_meta_uuid, &mp->m_sb.sb_meta_uuid))
                        xchk_block_set_corrupt(sc, bp);
        }

        if (xfs_has_metadir(mp)) {
                if (sb->sb_metadirino != cpu_to_be64(mp->m_sb.sb_metadirino))
                        xchk_block_set_preen(sc, bp);

                if (sb->sb_rgcount != cpu_to_be32(mp->m_sb.sb_rgcount))
                        xchk_block_set_corrupt(sc, bp);

                if (sb->sb_rgextents != cpu_to_be32(mp->m_sb.sb_rgextents))
                        xchk_block_set_corrupt(sc, bp);

                if (sb->sb_rgblklog != mp->m_sb.sb_rgblklog)
                        xchk_block_set_corrupt(sc, bp);

                if (memchr_inv(sb->sb_pad, 0, sizeof(sb->sb_pad)))
                        xchk_block_set_corrupt(sc, bp);
        }

        /* Everything else must be zero. */
        sblen = xchk_superblock_ondisk_size(mp);
        if (memchr_inv((char *)sb + sblen, 0, BBTOB(bp->b_length) - sblen))
                xchk_block_set_corrupt(sc, bp);

        xchk_superblock_xref(sc, bp);
out_pag:
        xfs_perag_put(pag);
        return error;
}

/* AGF */

/* Tally freespace record lengths. */
STATIC int
xchk_agf_record_bno_lengths(
        struct xfs_btree_cur            *cur,
        const struct xfs_alloc_rec_incore *rec,
        void                            *priv)
{
        xfs_extlen_t                    *blocks = priv;

        (*blocks) += rec->ar_blockcount;
        return 0;
}

/* Check agf_freeblks */
static inline void
xchk_agf_xref_freeblks(
        struct xfs_scrub        *sc)
{
        struct xfs_agf          *agf = sc->sa.agf_bp->b_addr;
        xfs_extlen_t            blocks = 0;
        int                     error;

        if (!sc->sa.bno_cur)
                return;

        error = xfs_alloc_query_all(sc->sa.bno_cur,
                        xchk_agf_record_bno_lengths, &blocks);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.bno_cur))
                return;
        if (blocks != be32_to_cpu(agf->agf_freeblks))
                xchk_block_xref_set_corrupt(sc, sc->sa.agf_bp);
}

/* Cross reference the AGF with the cntbt (freespace by length btree) */
static inline void
xchk_agf_xref_cntbt(
        struct xfs_scrub        *sc)
{
        struct xfs_agf          *agf = sc->sa.agf_bp->b_addr;
        xfs_agblock_t           agbno;
        xfs_extlen_t            blocks;
        int                     have;
        int                     error;

        if (!sc->sa.cnt_cur)
                return;

        /* Any freespace at all? */
        error = xfs_alloc_lookup_le(sc->sa.cnt_cur, 0, -1U, &have);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.cnt_cur))
                return;
        if (!have) {
                if (agf->agf_freeblks != cpu_to_be32(0))
                        xchk_block_xref_set_corrupt(sc, sc->sa.agf_bp);
                return;
        }

        /* Check agf_longest */
        error = xfs_alloc_get_rec(sc->sa.cnt_cur, &agbno, &blocks, &have);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.cnt_cur))
                return;
        if (!have || blocks != be32_to_cpu(agf->agf_longest))
                xchk_block_xref_set_corrupt(sc, sc->sa.agf_bp);
}

/* Check the btree block counts in the AGF against the btrees. */
STATIC void
xchk_agf_xref_btreeblks(
        struct xfs_scrub        *sc)
{
        struct xfs_agf          *agf = sc->sa.agf_bp->b_addr;
        struct xfs_mount        *mp = sc->mp;
        xfs_filblks_t           blocks;
        xfs_agblock_t           btreeblks;
        int                     error;

        /* agf_btreeblks didn't exist before lazysbcount */
        if (!xfs_has_lazysbcount(sc->mp))
                return;

        /* Check agf_rmap_blocks; set up for agf_btreeblks check */
        if (sc->sa.rmap_cur) {
                error = xfs_btree_count_blocks(sc->sa.rmap_cur, &blocks);
                if (!xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur))
                        return;
                btreeblks = blocks - 1;
                if (blocks != be32_to_cpu(agf->agf_rmap_blocks))
                        xchk_block_xref_set_corrupt(sc, sc->sa.agf_bp);
        } else {
                btreeblks = 0;
        }

        /*
         * No rmap cursor; we can't xref if we have the rmapbt feature.
         * We also can't do it if we're missing the free space btree cursors.
         */
        if ((xfs_has_rmapbt(mp) && !sc->sa.rmap_cur) ||
            !sc->sa.bno_cur || !sc->sa.cnt_cur)
                return;

        /* Check agf_btreeblks */
        error = xfs_btree_count_blocks(sc->sa.bno_cur, &blocks);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.bno_cur))
                return;
        btreeblks += blocks - 1;

        error = xfs_btree_count_blocks(sc->sa.cnt_cur, &blocks);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.cnt_cur))
                return;
        btreeblks += blocks - 1;

        if (btreeblks != be32_to_cpu(agf->agf_btreeblks))
                xchk_block_xref_set_corrupt(sc, sc->sa.agf_bp);
}

/* Check agf_refcount_blocks against tree size */
static inline void
xchk_agf_xref_refcblks(
        struct xfs_scrub        *sc)
{
        struct xfs_agf          *agf = sc->sa.agf_bp->b_addr;
        xfs_filblks_t           blocks;
        int                     error;

        if (!sc->sa.refc_cur)
                return;

        error = xfs_btree_count_blocks(sc->sa.refc_cur, &blocks);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.refc_cur))
                return;
        if (blocks != be32_to_cpu(agf->agf_refcount_blocks))
                xchk_block_xref_set_corrupt(sc, sc->sa.agf_bp);
}

/* Cross-reference with the other btrees. */
STATIC void
xchk_agf_xref(
        struct xfs_scrub        *sc)
{
        struct xfs_mount        *mp = sc->mp;
        xfs_agblock_t           agbno;

        if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                return;

        agbno = XFS_AGF_BLOCK(mp);

        xchk_ag_btcur_init(sc, &sc->sa);

        xchk_xref_is_used_space(sc, agbno, 1);
        xchk_agf_xref_freeblks(sc);
        xchk_agf_xref_cntbt(sc);
        xchk_xref_is_not_inode_chunk(sc, agbno, 1);
        xchk_xref_is_only_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
        xchk_agf_xref_btreeblks(sc);
        xchk_xref_is_not_shared(sc, agbno, 1);
        xchk_xref_is_not_cow_staging(sc, agbno, 1);
        xchk_agf_xref_refcblks(sc);

        /* scrub teardown will take care of sc->sa for us */
}

/* Scrub the AGF. */
int
xchk_agf(
        struct xfs_scrub        *sc)
{
        struct xfs_mount        *mp = sc->mp;
        struct xfs_agf          *agf;
        struct xfs_perag        *pag;
        xfs_agnumber_t          agno = sc->sm->sm_agno;
        xfs_agblock_t           agbno;
        xfs_agblock_t           eoag;
        xfs_agblock_t           agfl_first;
        xfs_agblock_t           agfl_last;
        xfs_agblock_t           agfl_count;
        xfs_agblock_t           fl_count;
        int                     level;
        int                     error = 0;

        error = xchk_ag_read_headers(sc, agno, &sc->sa);
        if (!xchk_process_error(sc, agno, XFS_AGF_BLOCK(sc->mp), &error))
                goto out;
        xchk_buffer_recheck(sc, sc->sa.agf_bp);

        agf = sc->sa.agf_bp->b_addr;
        pag = sc->sa.pag;

        /* Check the AG length */
        eoag = be32_to_cpu(agf->agf_length);
        if (eoag != pag_group(pag)->xg_block_count)
                xchk_block_set_corrupt(sc, sc->sa.agf_bp);

        /* Check the AGF btree roots and levels */
        agbno = be32_to_cpu(agf->agf_bno_root);
        if (!xfs_verify_agbno(pag, agbno))
                xchk_block_set_corrupt(sc, sc->sa.agf_bp);

        agbno = be32_to_cpu(agf->agf_cnt_root);
        if (!xfs_verify_agbno(pag, agbno))
                xchk_block_set_corrupt(sc, sc->sa.agf_bp);

        level = be32_to_cpu(agf->agf_bno_level);
        if (level <= 0 || level > mp->m_alloc_maxlevels)
                xchk_block_set_corrupt(sc, sc->sa.agf_bp);

        level = be32_to_cpu(agf->agf_cnt_level);
        if (level <= 0 || level > mp->m_alloc_maxlevels)
                xchk_block_set_corrupt(sc, sc->sa.agf_bp);

        if (xfs_has_rmapbt(mp)) {
                agbno = be32_to_cpu(agf->agf_rmap_root);
                if (!xfs_verify_agbno(pag, agbno))
                        xchk_block_set_corrupt(sc, sc->sa.agf_bp);

                level = be32_to_cpu(agf->agf_rmap_level);
                if (level <= 0 || level > mp->m_rmap_maxlevels)
                        xchk_block_set_corrupt(sc, sc->sa.agf_bp);
        }

        if (xfs_has_reflink(mp)) {
                agbno = be32_to_cpu(agf->agf_refcount_root);
                if (!xfs_verify_agbno(pag, agbno))
                        xchk_block_set_corrupt(sc, sc->sa.agf_bp);

                level = be32_to_cpu(agf->agf_refcount_level);
                if (level <= 0 || level > mp->m_refc_maxlevels)
                        xchk_block_set_corrupt(sc, sc->sa.agf_bp);
        }

        /* Check the AGFL counters */
        agfl_first = be32_to_cpu(agf->agf_flfirst);
        agfl_last = be32_to_cpu(agf->agf_fllast);
        agfl_count = be32_to_cpu(agf->agf_flcount);
        if (agfl_last > agfl_first)
                fl_count = agfl_last - agfl_first + 1;
        else
                fl_count = xfs_agfl_size(mp) - agfl_first + agfl_last + 1;
        if (agfl_count != 0 && fl_count != agfl_count)
                xchk_block_set_corrupt(sc, sc->sa.agf_bp);

        /* Do the incore counters match? */
        if (pag->pagf_freeblks != be32_to_cpu(agf->agf_freeblks))
                xchk_block_set_corrupt(sc, sc->sa.agf_bp);
        if (pag->pagf_flcount != be32_to_cpu(agf->agf_flcount))
                xchk_block_set_corrupt(sc, sc->sa.agf_bp);
        if (xfs_has_lazysbcount(sc->mp) &&
            pag->pagf_btreeblks != be32_to_cpu(agf->agf_btreeblks))
                xchk_block_set_corrupt(sc, sc->sa.agf_bp);

        xchk_agf_xref(sc);
out:
        return error;
}

/* AGFL */

struct xchk_agfl_info {
        /* Number of AGFL entries that the AGF claims are in use. */
        unsigned int            agflcount;

        /* Number of AGFL entries that we found. */
        unsigned int            nr_entries;

        /* Buffer to hold AGFL entries for extent checking. */
        xfs_agblock_t           *entries;

        struct xfs_buf          *agfl_bp;
        struct xfs_scrub        *sc;
};

/* Cross-reference with the other btrees. */
STATIC void
xchk_agfl_block_xref(
        struct xfs_scrub        *sc,
        xfs_agblock_t           agbno)
{
        if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                return;

        xchk_xref_is_used_space(sc, agbno, 1);
        xchk_xref_is_not_inode_chunk(sc, agbno, 1);
        xchk_xref_is_only_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_AG);
        xchk_xref_is_not_shared(sc, agbno, 1);
        xchk_xref_is_not_cow_staging(sc, agbno, 1);
}

/* Scrub an AGFL block. */
STATIC int
xchk_agfl_block(
        struct xfs_mount        *mp,
        xfs_agblock_t           agbno,
        void                    *priv)
{
        struct xchk_agfl_info   *sai = priv;
        struct xfs_scrub        *sc = sai->sc;

        if (xfs_verify_agbno(sc->sa.pag, agbno) &&
            sai->nr_entries < sai->agflcount)
                sai->entries[sai->nr_entries++] = agbno;
        else
                xchk_block_set_corrupt(sc, sai->agfl_bp);

        xchk_agfl_block_xref(sc, agbno);

        if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                return -ECANCELED;

        return 0;
}

static int
xchk_agblock_cmp(
        const void              *pa,
        const void              *pb)
{
        const xfs_agblock_t     *a = pa;
        const xfs_agblock_t     *b = pb;

        return (int)*a - (int)*b;
}

/* Cross-reference with the other btrees. */
STATIC void
xchk_agfl_xref(
        struct xfs_scrub        *sc)
{
        struct xfs_mount        *mp = sc->mp;
        xfs_agblock_t           agbno;

        if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                return;

        agbno = XFS_AGFL_BLOCK(mp);

        xchk_ag_btcur_init(sc, &sc->sa);

        xchk_xref_is_used_space(sc, agbno, 1);
        xchk_xref_is_not_inode_chunk(sc, agbno, 1);
        xchk_xref_is_only_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
        xchk_xref_is_not_shared(sc, agbno, 1);
        xchk_xref_is_not_cow_staging(sc, agbno, 1);

        /*
         * Scrub teardown will take care of sc->sa for us.  Leave sc->sa
         * active so that the agfl block xref can use it too.
         */
}

/* Scrub the AGFL. */
int
xchk_agfl(
        struct xfs_scrub        *sc)
{
        struct xchk_agfl_info   sai = {
                .sc             = sc,
        };
        struct xfs_agf          *agf;
        xfs_agnumber_t          agno = sc->sm->sm_agno;
        unsigned int            i;
        int                     error;

        /* Lock the AGF and AGI so that nobody can touch this AG. */
        error = xchk_ag_read_headers(sc, agno, &sc->sa);
        if (!xchk_process_error(sc, agno, XFS_AGFL_BLOCK(sc->mp), &error))
                return error;
        if (!sc->sa.agf_bp)
                return -EFSCORRUPTED;

        /* Try to read the AGFL, and verify its structure if we get it. */
        error = xfs_alloc_read_agfl(sc->sa.pag, sc->tp, &sai.agfl_bp);
        if (!xchk_process_error(sc, agno, XFS_AGFL_BLOCK(sc->mp), &error))
                return error;
        xchk_buffer_recheck(sc, sai.agfl_bp);

        xchk_agfl_xref(sc);

        if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                goto out;

        /* Allocate buffer to ensure uniqueness of AGFL entries. */
        agf = sc->sa.agf_bp->b_addr;
        sai.agflcount = be32_to_cpu(agf->agf_flcount);
        if (sai.agflcount > xfs_agfl_size(sc->mp)) {
                xchk_block_set_corrupt(sc, sc->sa.agf_bp);
                goto out;
        }
        sai.entries = kvzalloc_objs(xfs_agblock_t, sai.agflcount,
                                    XCHK_GFP_FLAGS);
        if (!sai.entries) {
                error = -ENOMEM;
                goto out;
        }

        /* Check the blocks in the AGFL. */
        error = xfs_agfl_walk(sc->mp, sc->sa.agf_bp->b_addr, sai.agfl_bp,
                        xchk_agfl_block, &sai);
        if (error == -ECANCELED) {
                error = 0;
                goto out_free;
        }
        if (error)
                goto out_free;

        if (sai.agflcount != sai.nr_entries) {
                xchk_block_set_corrupt(sc, sc->sa.agf_bp);
                goto out_free;
        }

        /* Sort entries, check for duplicates. */
        sort(sai.entries, sai.nr_entries, sizeof(sai.entries[0]),
                        xchk_agblock_cmp, NULL);
        for (i = 1; i < sai.nr_entries; i++) {
                if (sai.entries[i] == sai.entries[i - 1]) {
                        xchk_block_set_corrupt(sc, sc->sa.agf_bp);
                        break;
                }
        }

out_free:
        kvfree(sai.entries);
out:
        return error;
}

/* AGI */

/* Check agi_count/agi_freecount */
static inline void
xchk_agi_xref_icounts(
        struct xfs_scrub        *sc)
{
        struct xfs_agi          *agi = sc->sa.agi_bp->b_addr;
        xfs_agino_t             icount;
        xfs_agino_t             freecount;
        int                     error;

        if (!sc->sa.ino_cur)
                return;

        error = xfs_ialloc_count_inodes(sc->sa.ino_cur, &icount, &freecount);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.ino_cur))
                return;
        if (be32_to_cpu(agi->agi_count) != icount ||
            be32_to_cpu(agi->agi_freecount) != freecount)
                xchk_block_xref_set_corrupt(sc, sc->sa.agi_bp);
}

/* Check agi_[fi]blocks against tree size */
static inline void
xchk_agi_xref_fiblocks(
        struct xfs_scrub        *sc)
{
        struct xfs_agi          *agi = sc->sa.agi_bp->b_addr;
        xfs_filblks_t           blocks;
        int                     error = 0;

        if (!xfs_has_inobtcounts(sc->mp))
                return;

        if (sc->sa.ino_cur) {
                error = xfs_btree_count_blocks(sc->sa.ino_cur, &blocks);
                if (!xchk_should_check_xref(sc, &error, &sc->sa.ino_cur))
                        return;
                if (blocks != be32_to_cpu(agi->agi_iblocks))
                        xchk_block_xref_set_corrupt(sc, sc->sa.agi_bp);
        }

        if (sc->sa.fino_cur) {
                error = xfs_btree_count_blocks(sc->sa.fino_cur, &blocks);
                if (!xchk_should_check_xref(sc, &error, &sc->sa.fino_cur))
                        return;
                if (blocks != be32_to_cpu(agi->agi_fblocks))
                        xchk_block_xref_set_corrupt(sc, sc->sa.agi_bp);
        }
}

/* Cross-reference with the other btrees. */
STATIC void
xchk_agi_xref(
        struct xfs_scrub        *sc)
{
        struct xfs_mount        *mp = sc->mp;
        xfs_agblock_t           agbno;

        if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                return;

        agbno = XFS_AGI_BLOCK(mp);

        xchk_ag_btcur_init(sc, &sc->sa);

        xchk_xref_is_used_space(sc, agbno, 1);
        xchk_xref_is_not_inode_chunk(sc, agbno, 1);
        xchk_agi_xref_icounts(sc);
        xchk_xref_is_only_owned_by(sc, agbno, 1, &XFS_RMAP_OINFO_FS);
        xchk_xref_is_not_shared(sc, agbno, 1);
        xchk_xref_is_not_cow_staging(sc, agbno, 1);
        xchk_agi_xref_fiblocks(sc);

        /* scrub teardown will take care of sc->sa for us */
}

/*
 * Check the unlinked buckets for links to bad inodes.  We hold the AGI, so
 * there cannot be any threads updating unlinked list pointers in this AG.
 */
STATIC void
xchk_iunlink(
        struct xfs_scrub        *sc,
        struct xfs_agi          *agi)
{
        unsigned int            i;
        struct xfs_inode        *ip;

        for (i = 0; i < XFS_AGI_UNLINKED_BUCKETS; i++) {
                xfs_agino_t     agino = be32_to_cpu(agi->agi_unlinked[i]);

                while (agino != NULLAGINO) {
                        if (agino % XFS_AGI_UNLINKED_BUCKETS != i) {
                                xchk_block_set_corrupt(sc, sc->sa.agi_bp);
                                return;
                        }

                        ip = xfs_iunlink_lookup(sc->sa.pag, agino);
                        if (!ip) {
                                xchk_block_set_corrupt(sc, sc->sa.agi_bp);
                                return;
                        }

                        if (!xfs_inode_on_unlinked_list(ip)) {
                                xchk_block_set_corrupt(sc, sc->sa.agi_bp);
                                return;
                        }

                        agino = ip->i_next_unlinked;
                }
        }
}

/* Scrub the AGI. */
int
xchk_agi(
        struct xfs_scrub        *sc)
{
        struct xfs_mount        *mp = sc->mp;
        struct xfs_agi          *agi;
        struct xfs_perag        *pag;
        struct xfs_ino_geometry *igeo = M_IGEO(sc->mp);
        xfs_agnumber_t          agno = sc->sm->sm_agno;
        xfs_agblock_t           agbno;
        xfs_agblock_t           eoag;
        xfs_agino_t             agino;
        xfs_agino_t             first_agino;
        xfs_agino_t             last_agino;
        xfs_agino_t             icount;
        int                     i;
        int                     level;
        int                     error = 0;

        error = xchk_ag_read_headers(sc, agno, &sc->sa);
        if (!xchk_process_error(sc, agno, XFS_AGI_BLOCK(sc->mp), &error))
                goto out;
        xchk_buffer_recheck(sc, sc->sa.agi_bp);

        agi = sc->sa.agi_bp->b_addr;
        pag = sc->sa.pag;

        /* Check the AG length */
        eoag = be32_to_cpu(agi->agi_length);
        if (eoag != pag_group(pag)->xg_block_count)
                xchk_block_set_corrupt(sc, sc->sa.agi_bp);

        /* Check btree roots and levels */
        agbno = be32_to_cpu(agi->agi_root);
        if (!xfs_verify_agbno(pag, agbno))
                xchk_block_set_corrupt(sc, sc->sa.agi_bp);

        level = be32_to_cpu(agi->agi_level);
        if (level <= 0 || level > igeo->inobt_maxlevels)
                xchk_block_set_corrupt(sc, sc->sa.agi_bp);

        if (xfs_has_finobt(mp)) {
                agbno = be32_to_cpu(agi->agi_free_root);
                if (!xfs_verify_agbno(pag, agbno))
                        xchk_block_set_corrupt(sc, sc->sa.agi_bp);

                level = be32_to_cpu(agi->agi_free_level);
                if (level <= 0 || level > igeo->inobt_maxlevels)
                        xchk_block_set_corrupt(sc, sc->sa.agi_bp);
        }

        /* Check inode counters */
        xfs_agino_range(mp, agno, &first_agino, &last_agino);
        icount = be32_to_cpu(agi->agi_count);
        if (icount > last_agino - first_agino + 1 ||
            icount < be32_to_cpu(agi->agi_freecount))
                xchk_block_set_corrupt(sc, sc->sa.agi_bp);

        /* Check inode pointers */
        agino = be32_to_cpu(agi->agi_newino);
        if (!xfs_verify_agino_or_null(pag, agino))
                xchk_block_set_corrupt(sc, sc->sa.agi_bp);

        agino = be32_to_cpu(agi->agi_dirino);
        if (!xfs_verify_agino_or_null(pag, agino))
                xchk_block_set_corrupt(sc, sc->sa.agi_bp);

        /* Check unlinked inode buckets */
        for (i = 0; i < XFS_AGI_UNLINKED_BUCKETS; i++) {
                agino = be32_to_cpu(agi->agi_unlinked[i]);
                if (!xfs_verify_agino_or_null(pag, agino))
                        xchk_block_set_corrupt(sc, sc->sa.agi_bp);
        }

        if (agi->agi_pad32 != cpu_to_be32(0))
                xchk_block_set_corrupt(sc, sc->sa.agi_bp);

        /* Do the incore counters match? */
        if (pag->pagi_count != be32_to_cpu(agi->agi_count))
                xchk_block_set_corrupt(sc, sc->sa.agi_bp);
        if (pag->pagi_freecount != be32_to_cpu(agi->agi_freecount))
                xchk_block_set_corrupt(sc, sc->sa.agi_bp);

        xchk_iunlink(sc, agi);

        xchk_agi_xref(sc);
out:
        return error;
}