// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2016 Oracle.  All Rights Reserved.
 * Author: Darrick J. Wong <darrick.wong@oracle.com>
 */
#include "xfs_platform.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_btree.h"
#include "xfs_btree_staging.h"
#include "xfs_refcount_btree.h"
#include "xfs_refcount.h"
#include "xfs_alloc.h"
#include "xfs_error.h"
#include "xfs_health.h"
#include "xfs_trace.h"
#include "xfs_trans.h"
#include "xfs_bit.h"
#include "xfs_rmap.h"
#include "xfs_ag.h"

static struct kmem_cache        *xfs_refcountbt_cur_cache;

static struct xfs_btree_cur *
xfs_refcountbt_dup_cursor(
        struct xfs_btree_cur    *cur)
{
        return xfs_refcountbt_init_cursor(cur->bc_mp, cur->bc_tp,
                        cur->bc_ag.agbp, to_perag(cur->bc_group));
}

STATIC void
xfs_refcountbt_set_root(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_ptr       *ptr,
        int                             inc)
{
        struct xfs_buf          *agbp = cur->bc_ag.agbp;
        struct xfs_agf          *agf = agbp->b_addr;
        struct xfs_perag        *pag = agbp->b_pag;

        ASSERT(ptr->s != 0);

        agf->agf_refcount_root = ptr->s;
        be32_add_cpu(&agf->agf_refcount_level, inc);
        pag->pagf_refcount_level += inc;

        xfs_alloc_log_agf(cur->bc_tp, agbp,
                        XFS_AGF_REFCOUNT_ROOT | XFS_AGF_REFCOUNT_LEVEL);
}

STATIC int
xfs_refcountbt_alloc_block(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_ptr       *start,
        union xfs_btree_ptr             *new,
        int                             *stat)
{
        struct xfs_buf          *agbp = cur->bc_ag.agbp;
        struct xfs_agf          *agf = agbp->b_addr;
        struct xfs_alloc_arg    args;           /* block allocation args */
        int                     error;          /* error return value */

        memset(&args, 0, sizeof(args));
        args.tp = cur->bc_tp;
        args.mp = cur->bc_mp;
        args.pag = to_perag(cur->bc_group);
        args.oinfo = XFS_RMAP_OINFO_REFC;
        args.minlen = args.maxlen = args.prod = 1;
        args.resv = XFS_AG_RESV_METADATA;

        error = xfs_alloc_vextent_near_bno(&args,
                        xfs_agbno_to_fsb(args.pag, xfs_refc_block(args.mp)));
        if (error)
                goto out_error;
        if (args.fsbno == NULLFSBLOCK) {
                *stat = 0;
                return 0;
        }
        ASSERT(args.agno == cur->bc_group->xg_gno);
        ASSERT(args.len == 1);

        new->s = cpu_to_be32(args.agbno);
        be32_add_cpu(&agf->agf_refcount_blocks, 1);
        xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_REFCOUNT_BLOCKS);

        *stat = 1;
        return 0;

out_error:
        return error;
}

STATIC int
xfs_refcountbt_free_block(
        struct xfs_btree_cur    *cur,
        struct xfs_buf          *bp)
{
        struct xfs_mount        *mp = cur->bc_mp;
        struct xfs_buf          *agbp = cur->bc_ag.agbp;
        struct xfs_agf          *agf = agbp->b_addr;
        xfs_fsblock_t           fsbno = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));

        be32_add_cpu(&agf->agf_refcount_blocks, -1);
        xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_REFCOUNT_BLOCKS);
        return xfs_free_extent_later(cur->bc_tp, fsbno, 1,
                        &XFS_RMAP_OINFO_REFC, XFS_AG_RESV_METADATA, 0);
}

STATIC int
xfs_refcountbt_get_minrecs(
        struct xfs_btree_cur    *cur,
        int                     level)
{
        return cur->bc_mp->m_refc_mnr[level != 0];
}

STATIC int
xfs_refcountbt_get_maxrecs(
        struct xfs_btree_cur    *cur,
        int                     level)
{
        return cur->bc_mp->m_refc_mxr[level != 0];
}

STATIC void
xfs_refcountbt_init_key_from_rec(
        union xfs_btree_key             *key,
        const union xfs_btree_rec       *rec)
{
        key->refc.rc_startblock = rec->refc.rc_startblock;
}

STATIC void
xfs_refcountbt_init_high_key_from_rec(
        union xfs_btree_key             *key,
        const union xfs_btree_rec       *rec)
{
        __u32                           x;

        x = be32_to_cpu(rec->refc.rc_startblock);
        x += be32_to_cpu(rec->refc.rc_blockcount) - 1;
        key->refc.rc_startblock = cpu_to_be32(x);
}

STATIC void
xfs_refcountbt_init_rec_from_cur(
        struct xfs_btree_cur    *cur,
        union xfs_btree_rec     *rec)
{
        const struct xfs_refcount_irec *irec = &cur->bc_rec.rc;
        uint32_t                start;

        start = xfs_refcount_encode_startblock(irec->rc_startblock,
                        irec->rc_domain);
        rec->refc.rc_startblock = cpu_to_be32(start);
        rec->refc.rc_blockcount = cpu_to_be32(cur->bc_rec.rc.rc_blockcount);
        rec->refc.rc_refcount = cpu_to_be32(cur->bc_rec.rc.rc_refcount);
}

STATIC void
xfs_refcountbt_init_ptr_from_cur(
        struct xfs_btree_cur    *cur,
        union xfs_btree_ptr     *ptr)
{
        struct xfs_agf          *agf = cur->bc_ag.agbp->b_addr;

        ASSERT(cur->bc_group->xg_gno == be32_to_cpu(agf->agf_seqno));

        ptr->s = agf->agf_refcount_root;
}

STATIC int
xfs_refcountbt_cmp_key_with_cur(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_key       *key)
{
        const struct xfs_refcount_key   *kp = &key->refc;
        const struct xfs_refcount_irec  *irec = &cur->bc_rec.rc;
        uint32_t                        start;

        start = xfs_refcount_encode_startblock(irec->rc_startblock,
                        irec->rc_domain);
        return cmp_int(be32_to_cpu(kp->rc_startblock), start);
}

STATIC int
xfs_refcountbt_cmp_two_keys(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_key       *k1,
        const union xfs_btree_key       *k2,
        const union xfs_btree_key       *mask)
{
        ASSERT(!mask || mask->refc.rc_startblock);

        return cmp_int(be32_to_cpu(k1->refc.rc_startblock),
                       be32_to_cpu(k2->refc.rc_startblock));
}

STATIC xfs_failaddr_t
xfs_refcountbt_verify(
        struct xfs_buf          *bp)
{
        struct xfs_mount        *mp = bp->b_mount;
        struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
        struct xfs_perag        *pag = bp->b_pag;
        xfs_failaddr_t          fa;
        unsigned int            level;

        if (!xfs_verify_magic(bp, block->bb_magic))
                return __this_address;

        if (!xfs_has_reflink(mp))
                return __this_address;
        fa = xfs_btree_agblock_v5hdr_verify(bp);
        if (fa)
                return fa;

        level = be16_to_cpu(block->bb_level);
        if (pag && xfs_perag_initialised_agf(pag)) {
                unsigned int    maxlevel = pag->pagf_refcount_level;

#ifdef CONFIG_XFS_ONLINE_REPAIR
                /*
                 * Online repair could be rewriting the refcount btree, so
                 * we'll validate against the larger of either tree while this
                 * is going on.
                 */
                maxlevel = max_t(unsigned int, maxlevel,
                                pag->pagf_repair_refcount_level);
#endif
                if (level >= maxlevel)
                        return __this_address;
        } else if (level >= mp->m_refc_maxlevels)
                return __this_address;

        return xfs_btree_agblock_verify(bp, mp->m_refc_mxr[level != 0]);
}

STATIC void
xfs_refcountbt_read_verify(
        struct xfs_buf  *bp)
{
        xfs_failaddr_t  fa;

        if (!xfs_btree_agblock_verify_crc(bp))
                xfs_verifier_error(bp, -EFSBADCRC, __this_address);
        else {
                fa = xfs_refcountbt_verify(bp);
                if (fa)
                        xfs_verifier_error(bp, -EFSCORRUPTED, fa);
        }

        if (bp->b_error)
                trace_xfs_btree_corrupt(bp, _RET_IP_);
}

STATIC void
xfs_refcountbt_write_verify(
        struct xfs_buf  *bp)
{
        xfs_failaddr_t  fa;

        fa = xfs_refcountbt_verify(bp);
        if (fa) {
                trace_xfs_btree_corrupt(bp, _RET_IP_);
                xfs_verifier_error(bp, -EFSCORRUPTED, fa);
                return;
        }
        xfs_btree_agblock_calc_crc(bp);

}

const struct xfs_buf_ops xfs_refcountbt_buf_ops = {
        .name                   = "xfs_refcountbt",
        .magic                  = { 0, cpu_to_be32(XFS_REFC_CRC_MAGIC) },
        .verify_read            = xfs_refcountbt_read_verify,
        .verify_write           = xfs_refcountbt_write_verify,
        .verify_struct          = xfs_refcountbt_verify,
};

STATIC int
xfs_refcountbt_keys_inorder(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_key       *k1,
        const union xfs_btree_key       *k2)
{
        return be32_to_cpu(k1->refc.rc_startblock) <
               be32_to_cpu(k2->refc.rc_startblock);
}

STATIC int
xfs_refcountbt_recs_inorder(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_rec       *r1,
        const union xfs_btree_rec       *r2)
{
        return  be32_to_cpu(r1->refc.rc_startblock) +
                be32_to_cpu(r1->refc.rc_blockcount) <=
                be32_to_cpu(r2->refc.rc_startblock);
}

STATIC enum xbtree_key_contig
xfs_refcountbt_keys_contiguous(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_key       *key1,
        const union xfs_btree_key       *key2,
        const union xfs_btree_key       *mask)
{
        ASSERT(!mask || mask->refc.rc_startblock);

        return xbtree_key_contig(be32_to_cpu(key1->refc.rc_startblock),
                                 be32_to_cpu(key2->refc.rc_startblock));
}

const struct xfs_btree_ops xfs_refcountbt_ops = {
        .name                   = "refcount",
        .type                   = XFS_BTREE_TYPE_AG,

        .rec_len                = sizeof(struct xfs_refcount_rec),
        .key_len                = sizeof(struct xfs_refcount_key),
        .ptr_len                = XFS_BTREE_SHORT_PTR_LEN,

        .lru_refs               = XFS_REFC_BTREE_REF,
        .statoff                = XFS_STATS_CALC_INDEX(xs_refcbt_2),
        .sick_mask              = XFS_SICK_AG_REFCNTBT,

        .dup_cursor             = xfs_refcountbt_dup_cursor,
        .set_root               = xfs_refcountbt_set_root,
        .alloc_block            = xfs_refcountbt_alloc_block,
        .free_block             = xfs_refcountbt_free_block,
        .get_minrecs            = xfs_refcountbt_get_minrecs,
        .get_maxrecs            = xfs_refcountbt_get_maxrecs,
        .init_key_from_rec      = xfs_refcountbt_init_key_from_rec,
        .init_high_key_from_rec = xfs_refcountbt_init_high_key_from_rec,
        .init_rec_from_cur      = xfs_refcountbt_init_rec_from_cur,
        .init_ptr_from_cur      = xfs_refcountbt_init_ptr_from_cur,
        .cmp_key_with_cur       = xfs_refcountbt_cmp_key_with_cur,
        .buf_ops                = &xfs_refcountbt_buf_ops,
        .cmp_two_keys           = xfs_refcountbt_cmp_two_keys,
        .keys_inorder           = xfs_refcountbt_keys_inorder,
        .recs_inorder           = xfs_refcountbt_recs_inorder,
        .keys_contiguous        = xfs_refcountbt_keys_contiguous,
};

/*
 * Create a new refcount btree cursor.
 *
 * For staging cursors tp and agbp are NULL.
 */
struct xfs_btree_cur *
xfs_refcountbt_init_cursor(
        struct xfs_mount        *mp,
        struct xfs_trans        *tp,
        struct xfs_buf          *agbp,
        struct xfs_perag        *pag)
{
        struct xfs_btree_cur    *cur;

        ASSERT(pag_agno(pag) < mp->m_sb.sb_agcount);

        cur = xfs_btree_alloc_cursor(mp, tp, &xfs_refcountbt_ops,
                        mp->m_refc_maxlevels, xfs_refcountbt_cur_cache);
        cur->bc_group = xfs_group_hold(pag_group(pag));
        cur->bc_refc.nr_ops = 0;
        cur->bc_refc.shape_changes = 0;
        cur->bc_ag.agbp = agbp;
        if (agbp) {
                struct xfs_agf          *agf = agbp->b_addr;

                cur->bc_nlevels = be32_to_cpu(agf->agf_refcount_level);
        }
        return cur;
}

/*
 * Swap in the new btree root.  Once we pass this point the newly rebuilt btree
 * is in place and we have to kill off all the old btree blocks.
 */
void
xfs_refcountbt_commit_staged_btree(
        struct xfs_btree_cur    *cur,
        struct xfs_trans        *tp,
        struct xfs_buf          *agbp)
{
        struct xfs_agf          *agf = agbp->b_addr;
        struct xbtree_afakeroot *afake = cur->bc_ag.afake;

        ASSERT(cur->bc_flags & XFS_BTREE_STAGING);

        agf->agf_refcount_root = cpu_to_be32(afake->af_root);
        agf->agf_refcount_level = cpu_to_be32(afake->af_levels);
        agf->agf_refcount_blocks = cpu_to_be32(afake->af_blocks);
        xfs_alloc_log_agf(tp, agbp, XFS_AGF_REFCOUNT_BLOCKS |
                                    XFS_AGF_REFCOUNT_ROOT |
                                    XFS_AGF_REFCOUNT_LEVEL);
        xfs_btree_commit_afakeroot(cur, tp, agbp);
}

/* Calculate number of records in a refcount btree block. */
static inline unsigned int
xfs_refcountbt_block_maxrecs(
        unsigned int            blocklen,
        bool                    leaf)
{
        if (leaf)
                return blocklen / sizeof(struct xfs_refcount_rec);
        return blocklen / (sizeof(struct xfs_refcount_key) +
                           sizeof(xfs_refcount_ptr_t));
}

/*
 * Calculate the number of records in a refcount btree block.
 */
unsigned int
xfs_refcountbt_maxrecs(
        struct xfs_mount        *mp,
        unsigned int            blocklen,
        bool                    leaf)
{
        blocklen -= XFS_REFCOUNT_BLOCK_LEN;
        return xfs_refcountbt_block_maxrecs(blocklen, leaf);
}

/* Compute the max possible height of the maximally sized refcount btree. */
unsigned int
xfs_refcountbt_maxlevels_ondisk(void)
{
        unsigned int            minrecs[2];
        unsigned int            blocklen;

        blocklen = XFS_MIN_CRC_BLOCKSIZE - XFS_BTREE_SBLOCK_CRC_LEN;

        minrecs[0] = xfs_refcountbt_block_maxrecs(blocklen, true) / 2;
        minrecs[1] = xfs_refcountbt_block_maxrecs(blocklen, false) / 2;

        return xfs_btree_compute_maxlevels(minrecs, XFS_MAX_CRC_AG_BLOCKS);
}

/* Compute the maximum height of a refcount btree. */
void
xfs_refcountbt_compute_maxlevels(
        struct xfs_mount                *mp)
{
        if (!xfs_has_reflink(mp)) {
                mp->m_refc_maxlevels = 0;
                return;
        }

        mp->m_refc_maxlevels = xfs_btree_compute_maxlevels(
                        mp->m_refc_mnr, mp->m_sb.sb_agblocks);
        ASSERT(mp->m_refc_maxlevels <= xfs_refcountbt_maxlevels_ondisk());
}

/* Calculate the refcount btree size for some records. */
xfs_extlen_t
xfs_refcountbt_calc_size(
        struct xfs_mount        *mp,
        unsigned long long      len)
{
        return xfs_btree_calc_size(mp->m_refc_mnr, len);
}

/*
 * Calculate the maximum refcount btree size.
 */
xfs_extlen_t
xfs_refcountbt_max_size(
        struct xfs_mount        *mp,
        xfs_agblock_t           agblocks)
{
        /* Bail out if we're uninitialized, which can happen in mkfs. */
        if (mp->m_refc_mxr[0] == 0)
                return 0;

        return xfs_refcountbt_calc_size(mp, agblocks);
}

/*
 * Figure out how many blocks to reserve and how many are used by this btree.
 */
int
xfs_refcountbt_calc_reserves(
        struct xfs_mount        *mp,
        struct xfs_trans        *tp,
        struct xfs_perag        *pag,
        xfs_extlen_t            *ask,
        xfs_extlen_t            *used)
{
        struct xfs_buf          *agbp;
        struct xfs_agf          *agf;
        xfs_agblock_t           agblocks;
        xfs_extlen_t            tree_len;
        int                     error;

        if (!xfs_has_reflink(mp))
                return 0;

        error = xfs_alloc_read_agf(pag, tp, 0, &agbp);
        if (error)
                return error;

        agf = agbp->b_addr;
        agblocks = be32_to_cpu(agf->agf_length);
        tree_len = be32_to_cpu(agf->agf_refcount_blocks);
        xfs_trans_brelse(tp, agbp);

        /*
         * The log is permanently allocated, so the space it occupies will
         * never be available for the kinds of things that would require btree
         * expansion.  We therefore can pretend the space isn't there.
         */
        if (xfs_ag_contains_log(mp, pag_agno(pag)))
                agblocks -= mp->m_sb.sb_logblocks;

        *ask += xfs_refcountbt_max_size(mp, agblocks);
        *used += tree_len;

        return error;
}

int __init
xfs_refcountbt_init_cur_cache(void)
{
        xfs_refcountbt_cur_cache = kmem_cache_create("xfs_refcbt_cur",
                        xfs_btree_cur_sizeof(xfs_refcountbt_maxlevels_ondisk()),
                        0, 0, NULL);

        if (!xfs_refcountbt_cur_cache)
                return -ENOMEM;
        return 0;
}

void
xfs_refcountbt_destroy_cur_cache(void)
{
        kmem_cache_destroy(xfs_refcountbt_cur_cache);
        xfs_refcountbt_cur_cache = NULL;
}