// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2021-2024 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_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_alloc.h"
#include "xfs_btree.h"
#include "xfs_btree_staging.h"
#include "xfs_rtrefcount_btree.h"
#include "xfs_refcount.h"
#include "xfs_trace.h"
#include "xfs_cksum.h"
#include "xfs_error.h"
#include "xfs_extent_busy.h"
#include "xfs_rtgroup.h"
#include "xfs_rtbitmap.h"
#include "xfs_metafile.h"
#include "xfs_health.h"

static struct kmem_cache        *xfs_rtrefcountbt_cur_cache;

/*
 * Realtime Reference Count btree.
 *
 * This is a btree used to track the owner(s) of a given extent in the realtime
 * device.  See the comments in xfs_refcount_btree.c for more information.
 *
 * This tree is basically the same as the regular refcount btree except that
 * it's rooted in an inode.
 */

static struct xfs_btree_cur *
xfs_rtrefcountbt_dup_cursor(
        struct xfs_btree_cur    *cur)
{
        return xfs_rtrefcountbt_init_cursor(cur->bc_tp, to_rtg(cur->bc_group));
}

STATIC int
xfs_rtrefcountbt_get_minrecs(
        struct xfs_btree_cur    *cur,
        int                     level)
{
        if (level == cur->bc_nlevels - 1) {
                struct xfs_ifork        *ifp = xfs_btree_ifork_ptr(cur);

                return xfs_rtrefcountbt_maxrecs(cur->bc_mp, ifp->if_broot_bytes,
                                level == 0) / 2;
        }

        return cur->bc_mp->m_rtrefc_mnr[level != 0];
}

STATIC int
xfs_rtrefcountbt_get_maxrecs(
        struct xfs_btree_cur    *cur,
        int                     level)
{
        if (level == cur->bc_nlevels - 1) {
                struct xfs_ifork        *ifp = xfs_btree_ifork_ptr(cur);

                return xfs_rtrefcountbt_maxrecs(cur->bc_mp, ifp->if_broot_bytes,
                                level == 0);
        }

        return cur->bc_mp->m_rtrefc_mxr[level != 0];
}

/*
 * Calculate number of records in a realtime refcount btree inode root.
 */
unsigned int
xfs_rtrefcountbt_droot_maxrecs(
        unsigned int            blocklen,
        bool                    leaf)
{
        blocklen -= sizeof(struct xfs_rtrefcount_root);

        if (leaf)
                return blocklen / sizeof(struct xfs_refcount_rec);
        return blocklen / (2 * sizeof(struct xfs_refcount_key) +
                        sizeof(xfs_rtrefcount_ptr_t));
}

/*
 * Get the maximum records we could store in the on-disk format.
 *
 * For non-root nodes this is equivalent to xfs_rtrefcountbt_get_maxrecs, but
 * for the root node this checks the available space in the dinode fork so that
 * we can resize the in-memory buffer to match it.  After a resize to the
 * maximum size this function returns the same value as
 * xfs_rtrefcountbt_get_maxrecs for the root node, too.
 */
STATIC int
xfs_rtrefcountbt_get_dmaxrecs(
        struct xfs_btree_cur    *cur,
        int                     level)
{
        if (level != cur->bc_nlevels - 1)
                return cur->bc_mp->m_rtrefc_mxr[level != 0];
        return xfs_rtrefcountbt_droot_maxrecs(cur->bc_ino.forksize, level == 0);
}

STATIC void
xfs_rtrefcountbt_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_rtrefcountbt_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_rtrefcountbt_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_rtrefcountbt_init_ptr_from_cur(
        struct xfs_btree_cur    *cur,
        union xfs_btree_ptr     *ptr)
{
        ptr->l = 0;
}

STATIC int
xfs_rtrefcountbt_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_rtrefcountbt_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_rtrefcountbt_verify(
        struct xfs_buf          *bp)
{
        struct xfs_mount        *mp = bp->b_target->bt_mount;
        struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
        xfs_failaddr_t          fa;
        int                     level;

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

        if (!xfs_has_reflink(mp))
                return __this_address;
        fa = xfs_btree_fsblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
        if (fa)
                return fa;
        level = be16_to_cpu(block->bb_level);
        if (level > mp->m_rtrefc_maxlevels)
                return __this_address;

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

static void
xfs_rtrefcountbt_read_verify(
        struct xfs_buf  *bp)
{
        xfs_failaddr_t  fa;

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

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

static void
xfs_rtrefcountbt_write_verify(
        struct xfs_buf  *bp)
{
        xfs_failaddr_t  fa;

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

}

const struct xfs_buf_ops xfs_rtrefcountbt_buf_ops = {
        .name                   = "xfs_rtrefcountbt",
        .magic                  = { 0, cpu_to_be32(XFS_RTREFC_CRC_MAGIC) },
        .verify_read            = xfs_rtrefcountbt_read_verify,
        .verify_write           = xfs_rtrefcountbt_write_verify,
        .verify_struct          = xfs_rtrefcountbt_verify,
};

STATIC int
xfs_rtrefcountbt_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_rtrefcountbt_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_rtrefcountbt_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));
}

static inline void
xfs_rtrefcountbt_move_ptrs(
        struct xfs_mount        *mp,
        struct xfs_btree_block  *broot,
        short                   old_size,
        size_t                  new_size,
        unsigned int            numrecs)
{
        void                    *dptr;
        void                    *sptr;

        sptr = xfs_rtrefcount_broot_ptr_addr(mp, broot, 1, old_size);
        dptr = xfs_rtrefcount_broot_ptr_addr(mp, broot, 1, new_size);
        memmove(dptr, sptr, numrecs * sizeof(xfs_rtrefcount_ptr_t));
}

static struct xfs_btree_block *
xfs_rtrefcountbt_broot_realloc(
        struct xfs_btree_cur    *cur,
        unsigned int            new_numrecs)
{
        struct xfs_mount        *mp = cur->bc_mp;
        struct xfs_ifork        *ifp = xfs_btree_ifork_ptr(cur);
        struct xfs_btree_block  *broot;
        unsigned int            new_size;
        unsigned int            old_size = ifp->if_broot_bytes;
        const unsigned int      level = cur->bc_nlevels - 1;

        new_size = xfs_rtrefcount_broot_space_calc(mp, level, new_numrecs);

        /* Handle the nop case quietly. */
        if (new_size == old_size)
                return ifp->if_broot;

        if (new_size > old_size) {
                unsigned int    old_numrecs;

                /*
                 * If there wasn't any memory allocated before, just allocate
                 * it now and get out.
                 */
                if (old_size == 0)
                        return xfs_broot_realloc(ifp, new_size);

                /*
                 * If there is already an existing if_broot, then we need to
                 * realloc it and possibly move the node block pointers because
                 * those are not butted up against the btree block header.
                 */
                old_numrecs = xfs_rtrefcountbt_maxrecs(mp, old_size, level);
                broot = xfs_broot_realloc(ifp, new_size);
                if (level > 0)
                        xfs_rtrefcountbt_move_ptrs(mp, broot, old_size,
                                        new_size, old_numrecs);
                goto out_broot;
        }

        /*
         * We're reducing numrecs.  If we're going all the way to zero, just
         * free the block.
         */
        ASSERT(ifp->if_broot != NULL && old_size > 0);
        if (new_size == 0)
                return xfs_broot_realloc(ifp, 0);

        /*
         * Shrink the btree root by possibly moving the rtrmapbt pointers,
         * since they are not butted up against the btree block header.  Then
         * reallocate broot.
         */
        if (level > 0)
                xfs_rtrefcountbt_move_ptrs(mp, ifp->if_broot, old_size,
                                new_size, new_numrecs);
        broot = xfs_broot_realloc(ifp, new_size);

out_broot:
        ASSERT(xfs_rtrefcount_droot_space(broot) <=
               xfs_inode_fork_size(cur->bc_ino.ip, cur->bc_ino.whichfork));
        return broot;
}

const struct xfs_btree_ops xfs_rtrefcountbt_ops = {
        .name                   = "rtrefcount",
        .type                   = XFS_BTREE_TYPE_INODE,
        .geom_flags             = XFS_BTGEO_IROOT_RECORDS,

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

        .lru_refs               = XFS_REFC_BTREE_REF,
        .statoff                = XFS_STATS_CALC_INDEX(xs_rtrefcbt_2),
        .sick_mask              = XFS_SICK_RG_REFCNTBT,

        .dup_cursor             = xfs_rtrefcountbt_dup_cursor,
        .alloc_block            = xfs_btree_alloc_metafile_block,
        .free_block             = xfs_btree_free_metafile_block,
        .get_minrecs            = xfs_rtrefcountbt_get_minrecs,
        .get_maxrecs            = xfs_rtrefcountbt_get_maxrecs,
        .get_dmaxrecs           = xfs_rtrefcountbt_get_dmaxrecs,
        .init_key_from_rec      = xfs_rtrefcountbt_init_key_from_rec,
        .init_high_key_from_rec = xfs_rtrefcountbt_init_high_key_from_rec,
        .init_rec_from_cur      = xfs_rtrefcountbt_init_rec_from_cur,
        .init_ptr_from_cur      = xfs_rtrefcountbt_init_ptr_from_cur,
        .cmp_key_with_cur       = xfs_rtrefcountbt_cmp_key_with_cur,
        .buf_ops                = &xfs_rtrefcountbt_buf_ops,
        .cmp_two_keys           = xfs_rtrefcountbt_cmp_two_keys,
        .keys_inorder           = xfs_rtrefcountbt_keys_inorder,
        .recs_inorder           = xfs_rtrefcountbt_recs_inorder,
        .keys_contiguous        = xfs_rtrefcountbt_keys_contiguous,
        .broot_realloc          = xfs_rtrefcountbt_broot_realloc,
};

/* Allocate a new rt refcount btree cursor. */
struct xfs_btree_cur *
xfs_rtrefcountbt_init_cursor(
        struct xfs_trans        *tp,
        struct xfs_rtgroup      *rtg)
{
        struct xfs_inode        *ip = rtg_refcount(rtg);
        struct xfs_mount        *mp = rtg_mount(rtg);
        struct xfs_btree_cur    *cur;

        xfs_assert_ilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL);

        cur = xfs_btree_alloc_cursor(mp, tp, &xfs_rtrefcountbt_ops,
                        mp->m_rtrefc_maxlevels, xfs_rtrefcountbt_cur_cache);

        cur->bc_ino.ip = ip;
        cur->bc_refc.nr_ops = 0;
        cur->bc_refc.shape_changes = 0;
        cur->bc_group = xfs_group_hold(rtg_group(rtg));
        cur->bc_nlevels = be16_to_cpu(ip->i_df.if_broot->bb_level) + 1;
        cur->bc_ino.forksize = xfs_inode_fork_size(ip, XFS_DATA_FORK);
        cur->bc_ino.whichfork = XFS_DATA_FORK;
        return cur;
}

/*
 * Install a new rt reverse mapping btree root.  Caller is responsible for
 * invalidating and freeing the old btree blocks.
 */
void
xfs_rtrefcountbt_commit_staged_btree(
        struct xfs_btree_cur    *cur,
        struct xfs_trans        *tp)
{
        struct xbtree_ifakeroot *ifake = cur->bc_ino.ifake;
        struct xfs_ifork        *ifp;
        int                     flags = XFS_ILOG_CORE | XFS_ILOG_DBROOT;

        ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
        ASSERT(ifake->if_fork->if_format == XFS_DINODE_FMT_META_BTREE);

        /*
         * Free any resources hanging off the real fork, then shallow-copy the
         * staging fork's contents into the real fork to transfer everything
         * we just built.
         */
        ifp = xfs_ifork_ptr(cur->bc_ino.ip, XFS_DATA_FORK);
        xfs_idestroy_fork(ifp);
        memcpy(ifp, ifake->if_fork, sizeof(struct xfs_ifork));

        cur->bc_ino.ip->i_projid = cur->bc_group->xg_gno;
        xfs_trans_log_inode(tp, cur->bc_ino.ip, flags);
        xfs_btree_commit_ifakeroot(cur, tp, XFS_DATA_FORK);
}

/* Calculate number of records in a realtime refcount btree block. */
static inline unsigned int
xfs_rtrefcountbt_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_rtrefcount_ptr_t));
}

/*
 * Calculate number of records in an refcount btree block.
 */
unsigned int
xfs_rtrefcountbt_maxrecs(
        struct xfs_mount        *mp,
        unsigned int            blocklen,
        bool                    leaf)
{
        blocklen -= XFS_RTREFCOUNT_BLOCK_LEN;
        return xfs_rtrefcountbt_block_maxrecs(blocklen, leaf);
}

/* Compute the max possible height for realtime refcount btrees. */
unsigned int
xfs_rtrefcountbt_maxlevels_ondisk(void)
{
        unsigned int            minrecs[2];
        unsigned int            blocklen;

        blocklen = XFS_MIN_CRC_BLOCKSIZE - XFS_BTREE_LBLOCK_CRC_LEN;

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

        /* We need at most one record for every block in an rt group. */
        return xfs_btree_compute_maxlevels(minrecs, XFS_MAX_RGBLOCKS);
}

int __init
xfs_rtrefcountbt_init_cur_cache(void)
{
        xfs_rtrefcountbt_cur_cache = kmem_cache_create("xfs_rtrefcountbt_cur",
                        xfs_btree_cur_sizeof(
                                        xfs_rtrefcountbt_maxlevels_ondisk()),
                        0, 0, NULL);

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

void
xfs_rtrefcountbt_destroy_cur_cache(void)
{
        kmem_cache_destroy(xfs_rtrefcountbt_cur_cache);
        xfs_rtrefcountbt_cur_cache = NULL;
}

/* Compute the maximum height of a realtime refcount btree. */
void
xfs_rtrefcountbt_compute_maxlevels(
        struct xfs_mount        *mp)
{
        unsigned int            d_maxlevels, r_maxlevels;

        if (!xfs_has_rtreflink(mp)) {
                mp->m_rtrefc_maxlevels = 0;
                return;
        }

        /*
         * The realtime refcountbt lives on the data device, which means that
         * its maximum height is constrained by the size of the data device and
         * the height required to store one refcount record for each rtextent
         * in an rt group.
         */
        d_maxlevels = xfs_btree_space_to_height(mp->m_rtrefc_mnr,
                                mp->m_sb.sb_dblocks);
        r_maxlevels = xfs_btree_compute_maxlevels(mp->m_rtrefc_mnr,
                                mp->m_sb.sb_rgextents);

        /* Add one level to handle the inode root level. */
        mp->m_rtrefc_maxlevels = min(d_maxlevels, r_maxlevels) + 1;
}

/* Calculate the rtrefcount btree size for some records. */
unsigned long long
xfs_rtrefcountbt_calc_size(
        struct xfs_mount        *mp,
        unsigned long long      len)
{
        return xfs_btree_calc_size(mp->m_rtrefc_mnr, len);
}

/*
 * Calculate the maximum refcount btree size.
 */
static unsigned long long
xfs_rtrefcountbt_max_size(
        struct xfs_mount        *mp,
        xfs_rtblock_t           rtblocks)
{
        /* Bail out if we're uninitialized, which can happen in mkfs. */
        if (mp->m_rtrefc_mxr[0] == 0)
                return 0;

        return xfs_rtrefcountbt_calc_size(mp, rtblocks);
}

/*
 * Figure out how many blocks to reserve and how many are used by this btree.
 * We need enough space to hold one record for every rt extent in the rtgroup.
 */
xfs_filblks_t
xfs_rtrefcountbt_calc_reserves(
        struct xfs_mount        *mp)
{
        if (!xfs_has_rtreflink(mp))
                return 0;

        return xfs_rtrefcountbt_max_size(mp, mp->m_sb.sb_rgextents);
}

/*
 * Convert on-disk form of btree root to in-memory form.
 */
STATIC void
xfs_rtrefcountbt_from_disk(
        struct xfs_inode                *ip,
        struct xfs_rtrefcount_root      *dblock,
        int                             dblocklen,
        struct xfs_btree_block          *rblock)
{
        struct xfs_mount                *mp = ip->i_mount;
        struct xfs_refcount_key *fkp;
        __be64                          *fpp;
        struct xfs_refcount_key *tkp;
        __be64                          *tpp;
        struct xfs_refcount_rec *frp;
        struct xfs_refcount_rec *trp;
        unsigned int                    numrecs;
        unsigned int                    maxrecs;
        unsigned int                    rblocklen;

        rblocklen = xfs_rtrefcount_broot_space(mp, dblock);

        xfs_btree_init_block(mp, rblock, &xfs_rtrefcountbt_ops, 0, 0,
                        ip->i_ino);

        rblock->bb_level = dblock->bb_level;
        rblock->bb_numrecs = dblock->bb_numrecs;

        if (be16_to_cpu(rblock->bb_level) > 0) {
                maxrecs = xfs_rtrefcountbt_droot_maxrecs(dblocklen, false);
                fkp = xfs_rtrefcount_droot_key_addr(dblock, 1);
                tkp = xfs_rtrefcount_key_addr(rblock, 1);
                fpp = xfs_rtrefcount_droot_ptr_addr(dblock, 1, maxrecs);
                tpp = xfs_rtrefcount_broot_ptr_addr(mp, rblock, 1, rblocklen);
                numrecs = be16_to_cpu(dblock->bb_numrecs);
                memcpy(tkp, fkp, 2 * sizeof(*fkp) * numrecs);
                memcpy(tpp, fpp, sizeof(*fpp) * numrecs);
        } else {
                frp = xfs_rtrefcount_droot_rec_addr(dblock, 1);
                trp = xfs_rtrefcount_rec_addr(rblock, 1);
                numrecs = be16_to_cpu(dblock->bb_numrecs);
                memcpy(trp, frp, sizeof(*frp) * numrecs);
        }
}

/* Load a realtime reference count btree root in from disk. */
int
xfs_iformat_rtrefcount(
        struct xfs_inode        *ip,
        struct xfs_dinode       *dip)
{
        struct xfs_mount        *mp = ip->i_mount;
        struct xfs_rtrefcount_root *dfp = XFS_DFORK_PTR(dip, XFS_DATA_FORK);
        struct xfs_btree_block  *broot;
        unsigned int            numrecs;
        unsigned int            level;
        int                     dsize;

        /*
         * growfs must create the rtrefcount inodes before adding a realtime
         * volume to the filesystem, so we cannot use the rtrefcount predicate
         * here.
         */
        if (!xfs_has_reflink(ip->i_mount)) {
                xfs_inode_mark_sick(ip, XFS_SICK_INO_CORE);
                return -EFSCORRUPTED;
        }

        dsize = XFS_DFORK_SIZE(dip, mp, XFS_DATA_FORK);
        numrecs = be16_to_cpu(dfp->bb_numrecs);
        level = be16_to_cpu(dfp->bb_level);

        if (level > mp->m_rtrefc_maxlevels ||
            xfs_rtrefcount_droot_space_calc(level, numrecs) > dsize) {
                xfs_inode_mark_sick(ip, XFS_SICK_INO_CORE);
                return -EFSCORRUPTED;
        }

        broot = xfs_broot_alloc(xfs_ifork_ptr(ip, XFS_DATA_FORK),
                        xfs_rtrefcount_broot_space_calc(mp, level, numrecs));
        if (broot)
                xfs_rtrefcountbt_from_disk(ip, dfp, dsize, broot);
        return 0;
}

/*
 * Convert in-memory form of btree root to on-disk form.
 */
void
xfs_rtrefcountbt_to_disk(
        struct xfs_mount                *mp,
        struct xfs_btree_block          *rblock,
        int                             rblocklen,
        struct xfs_rtrefcount_root      *dblock,
        int                             dblocklen)
{
        struct xfs_refcount_key *fkp;
        __be64                          *fpp;
        struct xfs_refcount_key *tkp;
        __be64                          *tpp;
        struct xfs_refcount_rec *frp;
        struct xfs_refcount_rec *trp;
        unsigned int                    maxrecs;
        unsigned int                    numrecs;

        ASSERT(rblock->bb_magic == cpu_to_be32(XFS_RTREFC_CRC_MAGIC));
        ASSERT(uuid_equal(&rblock->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid));
        ASSERT(rblock->bb_u.l.bb_blkno == cpu_to_be64(XFS_BUF_DADDR_NULL));
        ASSERT(rblock->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK));
        ASSERT(rblock->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK));

        dblock->bb_level = rblock->bb_level;
        dblock->bb_numrecs = rblock->bb_numrecs;

        if (be16_to_cpu(rblock->bb_level) > 0) {
                maxrecs = xfs_rtrefcountbt_droot_maxrecs(dblocklen, false);
                fkp = xfs_rtrefcount_key_addr(rblock, 1);
                tkp = xfs_rtrefcount_droot_key_addr(dblock, 1);
                fpp = xfs_rtrefcount_broot_ptr_addr(mp, rblock, 1, rblocklen);
                tpp = xfs_rtrefcount_droot_ptr_addr(dblock, 1, maxrecs);
                numrecs = be16_to_cpu(rblock->bb_numrecs);
                memcpy(tkp, fkp, 2 * sizeof(*fkp) * numrecs);
                memcpy(tpp, fpp, sizeof(*fpp) * numrecs);
        } else {
                frp = xfs_rtrefcount_rec_addr(rblock, 1);
                trp = xfs_rtrefcount_droot_rec_addr(dblock, 1);
                numrecs = be16_to_cpu(rblock->bb_numrecs);
                memcpy(trp, frp, sizeof(*frp) * numrecs);
        }
}

/* Flush a realtime reference count btree root out to disk. */
void
xfs_iflush_rtrefcount(
        struct xfs_inode        *ip,
        struct xfs_dinode       *dip)
{
        struct xfs_ifork        *ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
        struct xfs_rtrefcount_root *dfp = XFS_DFORK_PTR(dip, XFS_DATA_FORK);

        ASSERT(ifp->if_broot != NULL);
        ASSERT(ifp->if_broot_bytes > 0);
        ASSERT(xfs_rtrefcount_droot_space(ifp->if_broot) <=
                        xfs_inode_fork_size(ip, XFS_DATA_FORK));
        xfs_rtrefcountbt_to_disk(ip->i_mount, ifp->if_broot,
                        ifp->if_broot_bytes, dfp,
                        XFS_DFORK_SIZE(dip, ip->i_mount, XFS_DATA_FORK));
}

/*
 * Create a realtime refcount btree inode.
 */
int
xfs_rtrefcountbt_create(
        struct xfs_rtgroup      *rtg,
        struct xfs_inode        *ip,
        struct xfs_trans        *tp,
        bool                    init)
{
        struct xfs_ifork        *ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
        struct xfs_mount        *mp = ip->i_mount;
        struct xfs_btree_block  *broot;

        ifp->if_format = XFS_DINODE_FMT_META_BTREE;
        ASSERT(ifp->if_broot_bytes == 0);
        ASSERT(ifp->if_bytes == 0);

        /* Initialize the empty incore btree root. */
        broot = xfs_broot_realloc(ifp,
                        xfs_rtrefcount_broot_space_calc(mp, 0, 0));
        if (broot)
                xfs_btree_init_block(mp, broot, &xfs_rtrefcountbt_ops, 0, 0,
                                ip->i_ino);
        xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE | XFS_ILOG_DBROOT);
        return 0;
}