// 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_log_format.h"
#include "xfs_trans.h"
#include "xfs_inode.h"
#include "xfs_ialloc.h"
#include "xfs_ialloc_btree.h"
#include "xfs_icache.h"
#include "xfs_rmap.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/btree.h"
#include "scrub/trace.h"
#include "xfs_ag.h"

/*
 * Set us up to scrub inode btrees.
 * If we detect a discrepancy between the inobt and the inode,
 * try again after forcing logged inode cores out to disk.
 */
int
xchk_setup_ag_iallocbt(
        struct xfs_scrub        *sc)
{
        return xchk_setup_ag_btree(sc, sc->flags & XCHK_TRY_HARDER);
}

/* Inode btree scrubber. */

struct xchk_iallocbt {
        /* Number of inodes we see while scanning inobt. */
        unsigned long long      inodes;

        /* Expected next startino, for big block filesystems. */
        xfs_agino_t             next_startino;

        /* Expected end of the current inode cluster. */
        xfs_agino_t             next_cluster_ino;
};

/*
 * If we're checking the finobt, cross-reference with the inobt.
 * Otherwise we're checking the inobt; if there is an finobt, make sure
 * we have a record or not depending on freecount.
 */
static inline void
xchk_iallocbt_chunk_xref_other(
        struct xfs_scrub                *sc,
        struct xfs_inobt_rec_incore     *irec,
        xfs_agino_t                     agino)
{
        struct xfs_btree_cur            **pcur;
        bool                            has_irec;
        int                             error;

        if (sc->sm->sm_type == XFS_SCRUB_TYPE_FINOBT)
                pcur = &sc->sa.ino_cur;
        else
                pcur = &sc->sa.fino_cur;
        if (!(*pcur))
                return;
        error = xfs_ialloc_has_inode_record(*pcur, agino, agino, &has_irec);
        if (!xchk_should_check_xref(sc, &error, pcur))
                return;
        if (((irec->ir_freecount > 0 && !has_irec) ||
             (irec->ir_freecount == 0 && has_irec)))
                xchk_btree_xref_set_corrupt(sc, *pcur, 0);
}

/* Cross-reference with the other btrees. */
STATIC void
xchk_iallocbt_chunk_xref(
        struct xfs_scrub                *sc,
        struct xfs_inobt_rec_incore     *irec,
        xfs_agino_t                     agino,
        xfs_agblock_t                   agbno,
        xfs_extlen_t                    len)
{
        if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                return;

        xchk_xref_is_used_space(sc, agbno, len);
        xchk_iallocbt_chunk_xref_other(sc, irec, agino);
        xchk_xref_is_owned_by(sc, agbno, len, &XFS_RMAP_OINFO_INODES);
        xchk_xref_is_not_shared(sc, agbno, len);
}

/* Is this chunk worth checking? */
STATIC bool
xchk_iallocbt_chunk(
        struct xchk_btree               *bs,
        struct xfs_inobt_rec_incore     *irec,
        xfs_agino_t                     agino,
        xfs_extlen_t                    len)
{
        struct xfs_mount                *mp = bs->cur->bc_mp;
        xfs_agnumber_t                  agno = bs->cur->bc_ag.pag->pag_agno;
        xfs_agblock_t                   bno;

        bno = XFS_AGINO_TO_AGBNO(mp, agino);
        if (bno + len <= bno ||
            !xfs_verify_agbno(mp, agno, bno) ||
            !xfs_verify_agbno(mp, agno, bno + len - 1))
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

        xchk_iallocbt_chunk_xref(bs->sc, irec, agino, bno, len);

        return true;
}

/* Count the number of free inodes. */
static unsigned int
xchk_iallocbt_freecount(
        xfs_inofree_t                   freemask)
{
        BUILD_BUG_ON(sizeof(freemask) != sizeof(__u64));
        return hweight64(freemask);
}

/*
 * Check that an inode's allocation status matches ir_free in the inobt
 * record.  First we try querying the in-core inode state, and if the inode
 * isn't loaded we examine the on-disk inode directly.
 *
 * Since there can be 1:M and M:1 mappings between inobt records and inode
 * clusters, we pass in the inode location information as an inobt record;
 * the index of an inode cluster within the inobt record (as well as the
 * cluster buffer itself); and the index of the inode within the cluster.
 *
 * @irec is the inobt record.
 * @irec_ino is the inode offset from the start of the record.
 * @dip is the on-disk inode.
 */
STATIC int
xchk_iallocbt_check_cluster_ifree(
        struct xchk_btree               *bs,
        struct xfs_inobt_rec_incore     *irec,
        unsigned int                    irec_ino,
        struct xfs_dinode               *dip)
{
        struct xfs_mount                *mp = bs->cur->bc_mp;
        xfs_ino_t                       fsino;
        xfs_agino_t                     agino;
        bool                            irec_free;
        bool                            ino_inuse;
        bool                            freemask_ok;
        int                             error = 0;

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

        /*
         * Given an inobt record and the offset of an inode from the start of
         * the record, compute which fs inode we're talking about.
         */
        agino = irec->ir_startino + irec_ino;
        fsino = XFS_AGINO_TO_INO(mp, bs->cur->bc_ag.pag->pag_agno, agino);
        irec_free = (irec->ir_free & XFS_INOBT_MASK(irec_ino));

        if (be16_to_cpu(dip->di_magic) != XFS_DINODE_MAGIC ||
            (dip->di_version >= 3 && be64_to_cpu(dip->di_ino) != fsino)) {
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
                goto out;
        }

        error = xfs_icache_inode_is_allocated(mp, bs->cur->bc_tp, fsino,
                        &ino_inuse);
        if (error == -ENODATA) {
                /* Not cached, just read the disk buffer */
                freemask_ok = irec_free ^ !!(dip->di_mode);
                if (!(bs->sc->flags & XCHK_TRY_HARDER) && !freemask_ok)
                        return -EDEADLOCK;
        } else if (error < 0) {
                /*
                 * Inode is only half assembled, or there was an IO error,
                 * or the verifier failed, so don't bother trying to check.
                 * The inode scrubber can deal with this.
                 */
                goto out;
        } else {
                /* Inode is all there. */
                freemask_ok = irec_free ^ ino_inuse;
        }
        if (!freemask_ok)
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
out:
        return 0;
}

/*
 * Check that the holemask and freemask of a hypothetical inode cluster match
 * what's actually on disk.  If sparse inodes are enabled, the cluster does
 * not actually have to map to inodes if the corresponding holemask bit is set.
 *
 * @cluster_base is the first inode in the cluster within the @irec.
 */
STATIC int
xchk_iallocbt_check_cluster(
        struct xchk_btree               *bs,
        struct xfs_inobt_rec_incore     *irec,
        unsigned int                    cluster_base)
{
        struct xfs_imap                 imap;
        struct xfs_mount                *mp = bs->cur->bc_mp;
        struct xfs_buf                  *cluster_bp;
        unsigned int                    nr_inodes;
        xfs_agnumber_t                  agno = bs->cur->bc_ag.pag->pag_agno;
        xfs_agblock_t                   agbno;
        unsigned int                    cluster_index;
        uint16_t                        cluster_mask = 0;
        uint16_t                        ir_holemask;
        int                             error = 0;

        nr_inodes = min_t(unsigned int, XFS_INODES_PER_CHUNK,
                        M_IGEO(mp)->inodes_per_cluster);

        /* Map this inode cluster */
        agbno = XFS_AGINO_TO_AGBNO(mp, irec->ir_startino + cluster_base);

        /* Compute a bitmask for this cluster that can be used for holemask. */
        for (cluster_index = 0;
             cluster_index < nr_inodes;
             cluster_index += XFS_INODES_PER_HOLEMASK_BIT)
                cluster_mask |= XFS_INOBT_MASK((cluster_base + cluster_index) /
                                XFS_INODES_PER_HOLEMASK_BIT);

        /*
         * Map the first inode of this cluster to a buffer and offset.
         * Be careful about inobt records that don't align with the start of
         * the inode buffer when block sizes are large enough to hold multiple
         * inode chunks.  When this happens, cluster_base will be zero but
         * ir_startino can be large enough to make im_boffset nonzero.
         */
        ir_holemask = (irec->ir_holemask & cluster_mask);
        imap.im_blkno = XFS_AGB_TO_DADDR(mp, agno, agbno);
        imap.im_len = XFS_FSB_TO_BB(mp, M_IGEO(mp)->blocks_per_cluster);
        imap.im_boffset = XFS_INO_TO_OFFSET(mp, irec->ir_startino) <<
                        mp->m_sb.sb_inodelog;

        if (imap.im_boffset != 0 && cluster_base != 0) {
                ASSERT(imap.im_boffset == 0 || cluster_base == 0);
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
                return 0;
        }

        trace_xchk_iallocbt_check_cluster(mp, agno, irec->ir_startino,
                        imap.im_blkno, imap.im_len, cluster_base, nr_inodes,
                        cluster_mask, ir_holemask,
                        XFS_INO_TO_OFFSET(mp, irec->ir_startino +
                                          cluster_base));

        /* The whole cluster must be a hole or not a hole. */
        if (ir_holemask != cluster_mask && ir_holemask != 0) {
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
                return 0;
        }

        /* If any part of this is a hole, skip it. */
        if (ir_holemask) {
                xchk_xref_is_not_owned_by(bs->sc, agbno,
                                M_IGEO(mp)->blocks_per_cluster,
                                &XFS_RMAP_OINFO_INODES);
                return 0;
        }

        xchk_xref_is_owned_by(bs->sc, agbno, M_IGEO(mp)->blocks_per_cluster,
                        &XFS_RMAP_OINFO_INODES);

        /* Grab the inode cluster buffer. */
        error = xfs_imap_to_bp(mp, bs->cur->bc_tp, &imap, &cluster_bp);
        if (!xchk_btree_xref_process_error(bs->sc, bs->cur, 0, &error))
                return error;

        /* Check free status of each inode within this cluster. */
        for (cluster_index = 0; cluster_index < nr_inodes; cluster_index++) {
                struct xfs_dinode       *dip;

                if (imap.im_boffset >= BBTOB(cluster_bp->b_length)) {
                        xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
                        break;
                }

                dip = xfs_buf_offset(cluster_bp, imap.im_boffset);
                error = xchk_iallocbt_check_cluster_ifree(bs, irec,
                                cluster_base + cluster_index, dip);
                if (error)
                        break;
                imap.im_boffset += mp->m_sb.sb_inodesize;
        }

        xfs_trans_brelse(bs->cur->bc_tp, cluster_bp);
        return error;
}

/*
 * For all the inode clusters that could map to this inobt record, make sure
 * that the holemask makes sense and that the allocation status of each inode
 * matches the freemask.
 */
STATIC int
xchk_iallocbt_check_clusters(
        struct xchk_btree               *bs,
        struct xfs_inobt_rec_incore     *irec)
{
        unsigned int                    cluster_base;
        int                             error = 0;

        /*
         * For the common case where this inobt record maps to multiple inode
         * clusters this will call _check_cluster for each cluster.
         *
         * For the case that multiple inobt records map to a single cluster,
         * this will call _check_cluster once.
         */
        for (cluster_base = 0;
             cluster_base < XFS_INODES_PER_CHUNK;
             cluster_base += M_IGEO(bs->sc->mp)->inodes_per_cluster) {
                error = xchk_iallocbt_check_cluster(bs, irec, cluster_base);
                if (error)
                        break;
        }

        return error;
}

/*
 * Make sure this inode btree record is aligned properly.  Because a fs block
 * contains multiple inodes, we check that the inobt record is aligned to the
 * correct inode, not just the correct block on disk.  This results in a finer
 * grained corruption check.
 */
STATIC void
xchk_iallocbt_rec_alignment(
        struct xchk_btree               *bs,
        struct xfs_inobt_rec_incore     *irec)
{
        struct xfs_mount                *mp = bs->sc->mp;
        struct xchk_iallocbt            *iabt = bs->private;
        struct xfs_ino_geometry         *igeo = M_IGEO(mp);

        /*
         * finobt records have different positioning requirements than inobt
         * records: each finobt record must have a corresponding inobt record.
         * That is checked in the xref function, so for now we only catch the
         * obvious case where the record isn't at all aligned properly.
         *
         * Note that if a fs block contains more than a single chunk of inodes,
         * we will have finobt records only for those chunks containing free
         * inodes, and therefore expect chunk alignment of finobt records.
         * Otherwise, we expect that the finobt record is aligned to the
         * cluster alignment as told by the superblock.
         */
        if (bs->cur->bc_btnum == XFS_BTNUM_FINO) {
                unsigned int    imask;

                imask = min_t(unsigned int, XFS_INODES_PER_CHUNK,
                                igeo->cluster_align_inodes) - 1;
                if (irec->ir_startino & imask)
                        xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
                return;
        }

        if (iabt->next_startino != NULLAGINO) {
                /*
                 * We're midway through a cluster of inodes that is mapped by
                 * multiple inobt records.  Did we get the record for the next
                 * irec in the sequence?
                 */
                if (irec->ir_startino != iabt->next_startino) {
                        xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
                        return;
                }

                iabt->next_startino += XFS_INODES_PER_CHUNK;

                /* Are we done with the cluster? */
                if (iabt->next_startino >= iabt->next_cluster_ino) {
                        iabt->next_startino = NULLAGINO;
                        iabt->next_cluster_ino = NULLAGINO;
                }
                return;
        }

        /* inobt records must be aligned to cluster and inoalignmnt size. */
        if (irec->ir_startino & (igeo->cluster_align_inodes - 1)) {
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
                return;
        }

        if (irec->ir_startino & (igeo->inodes_per_cluster - 1)) {
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
                return;
        }

        if (igeo->inodes_per_cluster <= XFS_INODES_PER_CHUNK)
                return;

        /*
         * If this is the start of an inode cluster that can be mapped by
         * multiple inobt records, the next inobt record must follow exactly
         * after this one.
         */
        iabt->next_startino = irec->ir_startino + XFS_INODES_PER_CHUNK;
        iabt->next_cluster_ino = irec->ir_startino + igeo->inodes_per_cluster;
}

/* Scrub an inobt/finobt record. */
STATIC int
xchk_iallocbt_rec(
        struct xchk_btree               *bs,
        const union xfs_btree_rec       *rec)
{
        struct xfs_mount                *mp = bs->cur->bc_mp;
        struct xchk_iallocbt            *iabt = bs->private;
        struct xfs_inobt_rec_incore     irec;
        uint64_t                        holes;
        xfs_agnumber_t                  agno = bs->cur->bc_ag.pag->pag_agno;
        xfs_agino_t                     agino;
        xfs_extlen_t                    len;
        int                             holecount;
        int                             i;
        int                             error = 0;
        unsigned int                    real_freecount;
        uint16_t                        holemask;

        xfs_inobt_btrec_to_irec(mp, rec, &irec);

        if (irec.ir_count > XFS_INODES_PER_CHUNK ||
            irec.ir_freecount > XFS_INODES_PER_CHUNK)
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

        real_freecount = irec.ir_freecount +
                        (XFS_INODES_PER_CHUNK - irec.ir_count);
        if (real_freecount != xchk_iallocbt_freecount(irec.ir_free))
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

        agino = irec.ir_startino;
        /* Record has to be properly aligned within the AG. */
        if (!xfs_verify_agino(mp, agno, agino) ||
            !xfs_verify_agino(mp, agno, agino + XFS_INODES_PER_CHUNK - 1)) {
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
                goto out;
        }

        xchk_iallocbt_rec_alignment(bs, &irec);
        if (bs->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
                goto out;

        iabt->inodes += irec.ir_count;

        /* Handle non-sparse inodes */
        if (!xfs_inobt_issparse(irec.ir_holemask)) {
                len = XFS_B_TO_FSB(mp,
                                XFS_INODES_PER_CHUNK * mp->m_sb.sb_inodesize);
                if (irec.ir_count != XFS_INODES_PER_CHUNK)
                        xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

                if (!xchk_iallocbt_chunk(bs, &irec, agino, len))
                        goto out;
                goto check_clusters;
        }

        /* Check each chunk of a sparse inode cluster. */
        holemask = irec.ir_holemask;
        holecount = 0;
        len = XFS_B_TO_FSB(mp,
                        XFS_INODES_PER_HOLEMASK_BIT * mp->m_sb.sb_inodesize);
        holes = ~xfs_inobt_irec_to_allocmask(&irec);
        if ((holes & irec.ir_free) != holes ||
            irec.ir_freecount > irec.ir_count)
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

        for (i = 0; i < XFS_INOBT_HOLEMASK_BITS; i++) {
                if (holemask & 1)
                        holecount += XFS_INODES_PER_HOLEMASK_BIT;
                else if (!xchk_iallocbt_chunk(bs, &irec, agino, len))
                        break;
                holemask >>= 1;
                agino += XFS_INODES_PER_HOLEMASK_BIT;
        }

        if (holecount > XFS_INODES_PER_CHUNK ||
            holecount + irec.ir_count != XFS_INODES_PER_CHUNK)
                xchk_btree_set_corrupt(bs->sc, bs->cur, 0);

check_clusters:
        error = xchk_iallocbt_check_clusters(bs, &irec);
        if (error)
                goto out;

out:
        return error;
}

/*
 * Make sure the inode btrees are as large as the rmap thinks they are.
 * Don't bother if we're missing btree cursors, as we're already corrupt.
 */
STATIC void
xchk_iallocbt_xref_rmap_btreeblks(
        struct xfs_scrub        *sc,
        int                     which)
{
        xfs_filblks_t           blocks;
        xfs_extlen_t            inobt_blocks = 0;
        xfs_extlen_t            finobt_blocks = 0;
        int                     error;

        if (!sc->sa.ino_cur || !sc->sa.rmap_cur ||
            (xfs_has_finobt(sc->mp) && !sc->sa.fino_cur) ||
            xchk_skip_xref(sc->sm))
                return;

        /* Check that we saw as many inobt blocks as the rmap says. */
        error = xfs_btree_count_blocks(sc->sa.ino_cur, &inobt_blocks);
        if (!xchk_process_error(sc, 0, 0, &error))
                return;

        if (sc->sa.fino_cur) {
                error = xfs_btree_count_blocks(sc->sa.fino_cur, &finobt_blocks);
                if (!xchk_process_error(sc, 0, 0, &error))
                        return;
        }

        error = xchk_count_rmap_ownedby_ag(sc, sc->sa.rmap_cur,
                        &XFS_RMAP_OINFO_INOBT, &blocks);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur))
                return;
        if (blocks != inobt_blocks + finobt_blocks)
                xchk_btree_set_corrupt(sc, sc->sa.ino_cur, 0);
}

/*
 * Make sure that the inobt records point to the same number of blocks as
 * the rmap says are owned by inodes.
 */
STATIC void
xchk_iallocbt_xref_rmap_inodes(
        struct xfs_scrub        *sc,
        int                     which,
        unsigned long long      inodes)
{
        xfs_filblks_t           blocks;
        xfs_filblks_t           inode_blocks;
        int                     error;

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

        /* Check that we saw as many inode blocks as the rmap knows about. */
        error = xchk_count_rmap_ownedby_ag(sc, sc->sa.rmap_cur,
                        &XFS_RMAP_OINFO_INODES, &blocks);
        if (!xchk_should_check_xref(sc, &error, &sc->sa.rmap_cur))
                return;
        inode_blocks = XFS_B_TO_FSB(sc->mp, inodes * sc->mp->m_sb.sb_inodesize);
        if (blocks != inode_blocks)
                xchk_btree_xref_set_corrupt(sc, sc->sa.rmap_cur, 0);
}

/* Scrub the inode btrees for some AG. */
STATIC int
xchk_iallocbt(
        struct xfs_scrub        *sc,
        xfs_btnum_t             which)
{
        struct xfs_btree_cur    *cur;
        struct xchk_iallocbt    iabt = {
                .inodes         = 0,
                .next_startino  = NULLAGINO,
                .next_cluster_ino = NULLAGINO,
        };
        int                     error;

        cur = which == XFS_BTNUM_INO ? sc->sa.ino_cur : sc->sa.fino_cur;
        error = xchk_btree(sc, cur, xchk_iallocbt_rec, &XFS_RMAP_OINFO_INOBT,
                        &iabt);
        if (error)
                return error;

        xchk_iallocbt_xref_rmap_btreeblks(sc, which);

        /*
         * If we're scrubbing the inode btree, inode_blocks is the number of
         * blocks pointed to by all the inode chunk records.  Therefore, we
         * should compare to the number of inode chunk blocks that the rmap
         * knows about.  We can't do this for the finobt since it only points
         * to inode chunks with free inodes.
         */
        if (which == XFS_BTNUM_INO)
                xchk_iallocbt_xref_rmap_inodes(sc, which, iabt.inodes);

        return error;
}

int
xchk_inobt(
        struct xfs_scrub        *sc)
{
        return xchk_iallocbt(sc, XFS_BTNUM_INO);
}

int
xchk_finobt(
        struct xfs_scrub        *sc)
{
        return xchk_iallocbt(sc, XFS_BTNUM_FINO);
}

/* See if an inode btree has (or doesn't have) an inode chunk record. */
static inline void
xchk_xref_inode_check(
        struct xfs_scrub        *sc,
        xfs_agblock_t           agbno,
        xfs_extlen_t            len,
        struct xfs_btree_cur    **icur,
        bool                    should_have_inodes)
{
        bool                    has_inodes;
        int                     error;

        if (!(*icur) || xchk_skip_xref(sc->sm))
                return;

        error = xfs_ialloc_has_inodes_at_extent(*icur, agbno, len, &has_inodes);
        if (!xchk_should_check_xref(sc, &error, icur))
                return;
        if (has_inodes != should_have_inodes)
                xchk_btree_xref_set_corrupt(sc, *icur, 0);
}

/* xref check that the extent is not covered by inodes */
void
xchk_xref_is_not_inode_chunk(
        struct xfs_scrub        *sc,
        xfs_agblock_t           agbno,
        xfs_extlen_t            len)
{
        xchk_xref_inode_check(sc, agbno, len, &sc->sa.ino_cur, false);
        xchk_xref_inode_check(sc, agbno, len, &sc->sa.fino_cur, false);
}

/* xref check that the extent is covered by inodes */
void
xchk_xref_is_inode_chunk(
        struct xfs_scrub        *sc,
        xfs_agblock_t           agbno,
        xfs_extlen_t            len)
{
        xchk_xref_inode_check(sc, agbno, len, &sc->sa.ino_cur, true);
}