// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2017 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_btree.h"
#include "xfs_rmap.h"
#include "xfs_refcount.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/btree.h"

/*
 * Set us up to scrub reverse mapping btrees.
 */
int
xchk_setup_ag_rmapbt(
        struct xfs_scrub        *sc,
        struct xfs_inode        *ip)
{
        return xchk_setup_ag_btree(sc, ip, false);
}

/* Reverse-mapping scrubber. */

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

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

        non_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->sa.refc_cur, irec->rm_startblock,
                        irec->rm_blockcount, &fbno, &flen, false);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.refc_cur))
                return;
        if (flen != 0 && (non_inode || is_attr || is_bmbt || is_unwritten))
                xchk_btree_xref_set_corrupt(sc, sc->sa.refc_cur, 0);
}

/* Cross-reference with the other btrees. */
STATIC void
xchk_rmapbt_xref(
        struct xfs_scrub        *sc,
        struct xfs_rmap_irec    *irec)
{
        xfs_agblock_t           agbno = irec->rm_startblock;
        xfs_extlen_t            len = irec->rm_blockcount;

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

        xchk_xref_is_used_space(sc, agbno, len);
        if (irec->rm_owner == XFS_RMAP_OWN_INODES)
                xchk_xref_is_inode_chunk(sc, agbno, len);
        else
                xchk_xref_is_not_inode_chunk(sc, agbno, len);
        if (irec->rm_owner == XFS_RMAP_OWN_COW)
                xchk_xref_is_cow_staging(sc, irec->rm_startblock,
                                irec->rm_blockcount);
        else
                xchk_rmapbt_xref_refc(sc, irec);
}

/* Scrub an rmapbt record. */
STATIC int
xchk_rmapbt_rec(
        struct xchk_btree       *bs,
        union xfs_btree_rec     *rec)
{
        struct xfs_mount        *mp = bs->cur->bc_mp;
        struct xfs_rmap_irec    irec;
        xfs_agnumber_t          agno = bs->cur->bc_private.a.agno;
        bool                    non_inode;
        bool                    is_unwritten;
        bool                    is_bmbt;
        bool                    is_attr;
        int                     error;

        error = xfs_rmap_btrec_to_irec(rec, &irec);
        if (!xchk_btree_process_error(bs->sc, bs->cur, 0, &error))
                goto out;

        /* Check extent. */
        if (irec.rm_startblock + irec.rm_blockcount <= irec.rm_startblock)
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

        if (irec.rm_owner == XFS_RMAP_OWN_FS) {
                /*
                 * xfs_verify_agbno returns false for static fs metadata.
                 * Since that only exists at the start of the AG, validate
                 * that by hand.
                 */
                if (irec.rm_startblock != 0 ||
                    irec.rm_blockcount != XFS_AGFL_BLOCK(mp) + 1)
                        xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
        } else {
                /*
                 * Otherwise we must point somewhere past the static metadata
                 * but before the end of the FS.  Run the regular check.
                 */
                if (!xfs_verify_agbno(mp, agno, irec.rm_startblock) ||
                    !xfs_verify_agbno(mp, agno, irec.rm_startblock +
                                irec.rm_blockcount - 1))
                        xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
        }

        /* Check flags. */
        non_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 (is_bmbt && irec.rm_offset != 0)
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

        if (non_inode && irec.rm_offset != 0)
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

        if (is_unwritten && (is_bmbt || non_inode || is_attr))
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

        if (non_inode && (is_bmbt || is_unwritten || is_attr))
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

        if (!non_inode) {
                if (!xfs_verify_ino(mp, irec.rm_owner))
                        xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
        } else {
                /* Non-inode owner within the magic values? */
                if (irec.rm_owner <= XFS_RMAP_OWN_MIN ||
                    irec.rm_owner > XFS_RMAP_OWN_FS)
                        xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
        }

        xchk_rmapbt_xref(bs->sc, &irec);
out:
        return error;
}

/* Scrub the rmap btree for some AG. */
int
xchk_rmapbt(
        struct xfs_scrub        *sc)
{
        return xchk_btree(sc, sc->sa.rmap_cur, xchk_rmapbt_rec,
                        &XFS_RMAP_OINFO_AG, NULL);
}

/* xref check that the extent is owned by a given owner */
static inline void
xchk_xref_check_owner(
        struct xfs_scrub                *sc,
        xfs_agblock_t                   bno,
        xfs_extlen_t                    len,
        const struct xfs_owner_info     *oinfo,
        bool                            should_have_rmap)
{
        bool                            has_rmap;
        int                             error;

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

        error = xfs_rmap_record_exists(sc->sa.rmap_cur, bno, len, oinfo,
                        &has_rmap);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur))
                return;
        if (has_rmap != should_have_rmap)
                xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0);
}

/* xref check that the extent is owned by a given owner */
void
xchk_xref_is_owned_by(
        struct xfs_scrub                *sc,
        xfs_agblock_t                   bno,
        xfs_extlen_t                    len,
        const struct xfs_owner_info     *oinfo)
{
        xchk_xref_check_owner(sc, bno, len, oinfo, true);
}

/* xref check that the extent is not owned by a given owner */
void
xchk_xref_is_not_owned_by(
        struct xfs_scrub                *sc,
        xfs_agblock_t                   bno,
        xfs_extlen_t                    len,
        const struct xfs_owner_info     *oinfo)
{
        xchk_xref_check_owner(sc, bno, len, oinfo, false);
}

/* xref check that the extent has no reverse mapping at all */
void
xchk_xref_has_no_owner(
        struct xfs_scrub        *sc,
        xfs_agblock_t           bno,
        xfs_extlen_t            len)
{
        bool                    has_rmap;
        int                     error;

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

        error = xfs_rmap_has_record(sc->sa.rmap_cur, bno, len, &has_rmap);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur))
                return;
        if (has_rmap)
                xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0);
}