// 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_log_format.h"
#include "xfs_trans.h"
#include "xfs_btree.h"
#include "xfs_alloc.h"
#include "xfs_rmap.h"
#include "xfs_ag.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/btree.h"
#include "scrub/repair.h"

/*
 * Set us up to scrub free space btrees.
 */
int
xchk_setup_ag_allocbt(
        struct xfs_scrub        *sc)
{
        int                     error;

        if (xchk_need_intent_drain(sc))
                xchk_fsgates_enable(sc, XCHK_FSGATES_DRAIN);

        error = xchk_setup_ag_btree(sc, false);
        if (error)
                return error;

        if (xchk_could_repair(sc))
                return xrep_setup_ag_allocbt(sc);

        return 0;
}

/* Free space btree scrubber. */

struct xchk_alloc {
        /* Previous free space extent. */
        struct xfs_alloc_rec_incore     prev;
};

/*
 * Ensure there's a corresponding cntbt/bnobt record matching this
 * bnobt/cntbt record, respectively.
 */
STATIC void
xchk_allocbt_xref_other(
        struct xfs_scrub        *sc,
        xfs_agblock_t           agbno,
        xfs_extlen_t            len)
{
        struct xfs_btree_cur    **pcur;
        xfs_agblock_t           fbno;
        xfs_extlen_t            flen;
        int                     has_otherrec;
        int                     error;

        if (sc->sm->sm_type == XFS_SCRUB_TYPE_BNOBT)
                pcur = &sc->sa.cnt_cur;
        else
                pcur = &sc->sa.bno_cur;
        if (!*pcur || xchk_skip_xref(sc->sm))
                return;

        error = xfs_alloc_lookup_le(*pcur, agbno, len, &has_otherrec);
        if (!xchk_should_check_xref(sc, &error, pcur))
                return;
        if (!has_otherrec) {
                xchk_btree_xref_set_corrupt(sc, *pcur, 0);
                return;
        }

        error = xfs_alloc_get_rec(*pcur, &fbno, &flen, &has_otherrec);
        if (!xchk_should_check_xref(sc, &error, pcur))
                return;
        if (!has_otherrec) {
                xchk_btree_xref_set_corrupt(sc, *pcur, 0);
                return;
        }

        if (fbno != agbno || flen != len)
                xchk_btree_xref_set_corrupt(sc, *pcur, 0);
}

/* Cross-reference with the other btrees. */
STATIC void
xchk_allocbt_xref(
        struct xfs_scrub        *sc,
        const struct xfs_alloc_rec_incore *irec)
{
        xfs_agblock_t           agbno = irec->ar_startblock;
        xfs_extlen_t            len = irec->ar_blockcount;

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

        xchk_allocbt_xref_other(sc, agbno, len);
        xchk_xref_is_not_inode_chunk(sc, agbno, len);
        xchk_xref_has_no_owner(sc, agbno, len);
        xchk_xref_is_not_shared(sc, agbno, len);
        xchk_xref_is_not_cow_staging(sc, agbno, len);
}

/* Flag failures for records that could be merged. */
STATIC void
xchk_allocbt_mergeable(
        struct xchk_btree       *bs,
        struct xchk_alloc       *ca,
        const struct xfs_alloc_rec_incore *irec)
{
        if (bs->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                return;

        if (ca->prev.ar_blockcount > 0 &&
            ca->prev.ar_startblock + ca->prev.ar_blockcount == irec->ar_startblock &&
            ca->prev.ar_blockcount + irec->ar_blockcount < (uint32_t)~0U)
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

        memcpy(&ca->prev, irec, sizeof(*irec));
}

/* Scrub a bnobt/cntbt record. */
STATIC int
xchk_allocbt_rec(
        struct xchk_btree               *bs,
        const union xfs_btree_rec       *rec)
{
        struct xfs_alloc_rec_incore     irec;
        struct xchk_alloc       *ca = bs->private;

        xfs_alloc_btrec_to_irec(rec, &irec);
        if (xfs_alloc_check_irec(to_perag(bs->cur->bc_group), &irec) != NULL) {
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
                return 0;
        }

        xchk_allocbt_mergeable(bs, ca, &irec);
        xchk_allocbt_xref(bs->sc, &irec);

        return 0;
}

/* Scrub one of the freespace btrees for some AG. */
int
xchk_allocbt(
        struct xfs_scrub        *sc)
{
        struct xchk_alloc       ca = { };
        struct xfs_btree_cur    *cur;

        switch (sc->sm->sm_type) {
        case XFS_SCRUB_TYPE_BNOBT:
                cur = sc->sa.bno_cur;
                break;
        case XFS_SCRUB_TYPE_CNTBT:
                cur = sc->sa.cnt_cur;
                break;
        default:
                ASSERT(0);
                return -EIO;
        }

        return xchk_btree(sc, cur, xchk_allocbt_rec, &XFS_RMAP_OINFO_AG, &ca);
}

/* xref check that the extent is not free */
void
xchk_xref_is_used_space(
        struct xfs_scrub        *sc,
        xfs_agblock_t           agbno,
        xfs_extlen_t            len)
{
        enum xbtree_recpacking  outcome;
        int                     error;

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

        error = xfs_alloc_has_records(sc->sa.bno_cur, agbno, len, &outcome);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.bno_cur))
                return;
        if (outcome != XBTREE_RECPACKING_EMPTY)
                xchk_btree_xref_set_corrupt(sc, sc->sa.bno_cur, 0);
}