// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2018-2024 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_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_rmap.h"
#include "xfs_rmap_btree.h"
#include "xfs_rtrmap_btree.h"
#include "xfs_inode.h"
#include "xfs_rtalloc.h"
#include "xfs_rtgroup.h"
#include "xfs_metafile.h"
#include "xfs_refcount.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"

/* Set us up with the realtime metadata locked. */
int
xchk_setup_rtrmapbt(
        struct xfs_scrub        *sc)
{
        int                     error;

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

        if (xchk_could_repair(sc)) {
                error = xrep_setup_rtrmapbt(sc);
                if (error)
                        return error;
        }

        error = xchk_rtgroup_init(sc, sc->sm->sm_agno, &sc->sr);
        if (error)
                return error;

        error = xchk_setup_rt(sc);
        if (error)
                return error;

        error = xchk_install_live_inode(sc, rtg_rmap(sc->sr.rtg));
        if (error)
                return error;

        return xchk_rtgroup_lock(sc, &sc->sr, XCHK_RTGLOCK_ALL);
}

/* Realtime reverse mapping. */

struct xchk_rtrmap {
        /*
         * The furthest-reaching of the rmapbt records that we've already
         * processed.  This enables us to detect overlapping records for space
         * allocations that cannot be shared.
         */
        struct xfs_rmap_irec    overlap_rec;

        /*
         * The previous rmapbt record, so that we can check for two records
         * that could be one.
         */
        struct xfs_rmap_irec    prev_rec;
};

static inline bool
xchk_rtrmapbt_is_shareable(
        struct xfs_scrub                *sc,
        const struct xfs_rmap_irec      *irec)
{
        if (!xfs_has_rtreflink(sc->mp))
                return false;
        if (irec->rm_flags & XFS_RMAP_UNWRITTEN)
                return false;
        return true;
}

/* Flag failures for records that overlap but cannot. */
STATIC void
xchk_rtrmapbt_check_overlapping(
        struct xchk_btree               *bs,
        struct xchk_rtrmap              *cr,
        const struct xfs_rmap_irec      *irec)
{
        xfs_rtblock_t                   pnext, inext;

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

        /* No previous record? */
        if (cr->overlap_rec.rm_blockcount == 0)
                goto set_prev;

        /* Do overlap_rec and irec overlap? */
        pnext = cr->overlap_rec.rm_startblock + cr->overlap_rec.rm_blockcount;
        if (pnext <= irec->rm_startblock)
                goto set_prev;

        /* Overlap is only allowed if both records are data fork mappings. */
        if (!xchk_rtrmapbt_is_shareable(bs->sc, &cr->overlap_rec) ||
            !xchk_rtrmapbt_is_shareable(bs->sc, irec))
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

        /* Save whichever rmap record extends furthest. */
        inext = irec->rm_startblock + irec->rm_blockcount;
        if (pnext > inext)
                return;

set_prev:
        memcpy(&cr->overlap_rec, irec, sizeof(struct xfs_rmap_irec));
}

/* Decide if two reverse-mapping records can be merged. */
static inline bool
xchk_rtrmap_mergeable(
        struct xchk_rtrmap              *cr,
        const struct xfs_rmap_irec      *r2)
{
        const struct xfs_rmap_irec      *r1 = &cr->prev_rec;

        /* Ignore if prev_rec is not yet initialized. */
        if (cr->prev_rec.rm_blockcount == 0)
                return false;

        if (r1->rm_owner != r2->rm_owner)
                return false;
        if (r1->rm_startblock + r1->rm_blockcount != r2->rm_startblock)
                return false;
        if ((unsigned long long)r1->rm_blockcount + r2->rm_blockcount >
            XFS_RMAP_LEN_MAX)
                return false;
        if (r1->rm_flags != r2->rm_flags)
                return false;
        return r1->rm_offset + r1->rm_blockcount == r2->rm_offset;
}

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

        if (xchk_rtrmap_mergeable(cr, irec))
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

        memcpy(&cr->prev_rec, irec, sizeof(struct xfs_rmap_irec));
}

/* Cross-reference a rmap against the refcount btree. */
STATIC void
xchk_rtrmapbt_xref_rtrefc(
        struct xfs_scrub        *sc,
        struct xfs_rmap_irec    *irec)
{
        xfs_rgblock_t           fbno;
        xfs_extlen_t            flen;
        bool                    is_inode;
        bool                    is_bmbt;
        bool                    is_attr;
        bool                    is_unwritten;
        int                     error;

        if (!sc->sr.refc_cur || xchk_skip_xref(sc->sm))
                return;

        is_inode = !XFS_RMAP_NON_INODE_OWNER(irec->rm_owner);
        is_bmbt = irec->rm_flags & XFS_RMAP_BMBT_BLOCK;
        is_attr = irec->rm_flags & XFS_RMAP_ATTR_FORK;
        is_unwritten = irec->rm_flags & XFS_RMAP_UNWRITTEN;

        /* If this is shared, must be a data fork extent. */
        error = xfs_refcount_find_shared(sc->sr.refc_cur, irec->rm_startblock,
                        irec->rm_blockcount, &fbno, &flen, false);
        if (!xchk_should_check_xref(sc, &error, &sc->sr.refc_cur))
                return;
        if (flen != 0 && (!is_inode || is_attr || is_bmbt || is_unwritten))
                xchk_btree_xref_set_corrupt(sc, sc->sr.refc_cur, 0);
}

/* Cross-reference with other metadata. */
STATIC void
xchk_rtrmapbt_xref(
        struct xfs_scrub        *sc,
        struct xfs_rmap_irec    *irec)
{
        if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                return;

        xchk_xref_is_used_rt_space(sc,
                        xfs_rgbno_to_rtb(sc->sr.rtg, irec->rm_startblock),
                        irec->rm_blockcount);
        if (irec->rm_owner == XFS_RMAP_OWN_COW)
                xchk_xref_is_cow_staging(sc, irec->rm_startblock,
                                irec->rm_blockcount);
        else
                xchk_rtrmapbt_xref_rtrefc(sc, irec);
}

/* Scrub a realtime rmapbt record. */
STATIC int
xchk_rtrmapbt_rec(
        struct xchk_btree               *bs,
        const union xfs_btree_rec       *rec)
{
        struct xchk_rtrmap              *cr = bs->private;
        struct xfs_rmap_irec            irec;

        if (xfs_rmap_btrec_to_irec(rec, &irec) != NULL ||
            xfs_rtrmap_check_irec(to_rtg(bs->cur->bc_group), &irec) != NULL) {
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
                return 0;
        }

        if (bs->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                return 0;

        xchk_rtrmapbt_check_mergeable(bs, cr, &irec);
        xchk_rtrmapbt_check_overlapping(bs, cr, &irec);
        xchk_rtrmapbt_xref(bs->sc, &irec);
        return 0;
}

/* Scrub the realtime rmap btree. */
int
xchk_rtrmapbt(
        struct xfs_scrub        *sc)
{
        struct xfs_inode        *ip = rtg_rmap(sc->sr.rtg);
        struct xfs_owner_info   oinfo;
        struct xchk_rtrmap      cr = { };
        int                     error;

        error = xchk_metadata_inode_forks(sc);
        if (error || (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
                return error;

        xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, XFS_DATA_FORK);
        return xchk_btree(sc, sc->sr.rmap_cur, xchk_rtrmapbt_rec, &oinfo, &cr);
}

/* xref check that the extent has no realtime reverse mapping at all */
void
xchk_xref_has_no_rt_owner(
        struct xfs_scrub        *sc,
        xfs_rgblock_t           bno,
        xfs_extlen_t            len)
{
        enum xbtree_recpacking  outcome;
        int                     error;

        if (!sc->sr.rmap_cur || xchk_skip_xref(sc->sm))
                return;

        error = xfs_rmap_has_records(sc->sr.rmap_cur, bno, len, &outcome);
        if (!xchk_should_check_xref(sc, &error, &sc->sr.rmap_cur))
                return;
        if (outcome != XBTREE_RECPACKING_EMPTY)
                xchk_btree_xref_set_corrupt(sc, sc->sr.rmap_cur, 0);
}

/* xref check that the extent is completely mapped */
void
xchk_xref_has_rt_owner(
        struct xfs_scrub        *sc,
        xfs_rgblock_t           bno,
        xfs_extlen_t            len)
{
        enum xbtree_recpacking  outcome;
        int                     error;

        if (!sc->sr.rmap_cur || xchk_skip_xref(sc->sm))
                return;

        error = xfs_rmap_has_records(sc->sr.rmap_cur, bno, len, &outcome);
        if (!xchk_should_check_xref(sc, &error, &sc->sr.rmap_cur))
                return;
        if (outcome != XBTREE_RECPACKING_FULL)
                xchk_btree_xref_set_corrupt(sc, sc->sr.rmap_cur, 0);
}

/* xref check that the extent is only owned by a given owner */
void
xchk_xref_is_only_rt_owned_by(
        struct xfs_scrub                *sc,
        xfs_agblock_t                   bno,
        xfs_extlen_t                    len,
        const struct xfs_owner_info     *oinfo)
{
        struct xfs_rmap_matches         res;
        int                             error;

        if (!sc->sr.rmap_cur || xchk_skip_xref(sc->sm))
                return;

        error = xfs_rmap_count_owners(sc->sr.rmap_cur, bno, len, oinfo, &res);
        if (!xchk_should_check_xref(sc, &error, &sc->sr.rmap_cur))
                return;
        if (res.matches != 1)
                xchk_btree_xref_set_corrupt(sc, sc->sr.rmap_cur, 0);
        if (res.bad_non_owner_matches)
                xchk_btree_xref_set_corrupt(sc, sc->sr.rmap_cur, 0);
        if (res.non_owner_matches)
                xchk_btree_xref_set_corrupt(sc, sc->sr.rmap_cur, 0);
}