// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 */
#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_mount.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_alloc.h"
#include "xfs_btree.h"
#include "xfs_btree_staging.h"
#include "xfs_bmap_btree.h"
#include "xfs_bmap.h"
#include "xfs_error.h"
#include "xfs_quota.h"
#include "xfs_trace.h"
#include "xfs_rmap.h"
#include "xfs_ag.h"

static struct kmem_cache        *xfs_bmbt_cur_cache;

void
xfs_bmbt_init_block(
        struct xfs_inode                *ip,
        struct xfs_btree_block          *buf,
        struct xfs_buf                  *bp,
        __u16                           level,
        __u16                           numrecs)
{
        if (bp)
                xfs_btree_init_buf(ip->i_mount, bp, &xfs_bmbt_ops, level,
                                numrecs, ip->i_ino);
        else
                xfs_btree_init_block(ip->i_mount, buf, &xfs_bmbt_ops, level,
                                numrecs, ip->i_ino);
}

/*
 * Convert on-disk form of btree root to in-memory form.
 */
void
xfs_bmdr_to_bmbt(
        struct xfs_inode        *ip,
        xfs_bmdr_block_t        *dblock,
        int                     dblocklen,
        struct xfs_btree_block  *rblock,
        int                     rblocklen)
{
        struct xfs_mount        *mp = ip->i_mount;
        int                     dmxr;
        xfs_bmbt_key_t          *fkp;
        __be64                  *fpp;
        xfs_bmbt_key_t          *tkp;
        __be64                  *tpp;

        xfs_bmbt_init_block(ip, rblock, NULL, 0, 0);
        rblock->bb_level = dblock->bb_level;
        ASSERT(be16_to_cpu(rblock->bb_level) > 0);
        rblock->bb_numrecs = dblock->bb_numrecs;
        dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
        fkp = xfs_bmdr_key_addr(dblock, 1);
        tkp = xfs_bmbt_key_addr(mp, rblock, 1);
        fpp = xfs_bmdr_ptr_addr(dblock, 1, dmxr);
        tpp = xfs_bmap_broot_ptr_addr(mp, rblock, 1, rblocklen);
        dmxr = be16_to_cpu(dblock->bb_numrecs);
        memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
        memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
}

void
xfs_bmbt_disk_get_all(
        const struct xfs_bmbt_rec *rec,
        struct xfs_bmbt_irec    *irec)
{
        uint64_t                l0 = get_unaligned_be64(&rec->l0);
        uint64_t                l1 = get_unaligned_be64(&rec->l1);

        irec->br_startoff = (l0 & xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
        irec->br_startblock = ((l0 & xfs_mask64lo(9)) << 43) | (l1 >> 21);
        irec->br_blockcount = l1 & xfs_mask64lo(21);
        if (l0 >> (64 - BMBT_EXNTFLAG_BITLEN))
                irec->br_state = XFS_EXT_UNWRITTEN;
        else
                irec->br_state = XFS_EXT_NORM;
}

/*
 * Extract the blockcount field from an on disk bmap extent record.
 */
xfs_filblks_t
xfs_bmbt_disk_get_blockcount(
        const struct xfs_bmbt_rec       *r)
{
        return (xfs_filblks_t)(be64_to_cpu(r->l1) & xfs_mask64lo(21));
}

/*
 * Extract the startoff field from a disk format bmap extent record.
 */
xfs_fileoff_t
xfs_bmbt_disk_get_startoff(
        const struct xfs_bmbt_rec       *r)
{
        return ((xfs_fileoff_t)be64_to_cpu(r->l0) &
                 xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
}

/*
 * Set all the fields in a bmap extent record from the uncompressed form.
 */
void
xfs_bmbt_disk_set_all(
        struct xfs_bmbt_rec     *r,
        struct xfs_bmbt_irec    *s)
{
        int                     extent_flag = (s->br_state != XFS_EXT_NORM);

        ASSERT(s->br_state == XFS_EXT_NORM || s->br_state == XFS_EXT_UNWRITTEN);
        ASSERT(!(s->br_startoff & xfs_mask64hi(64-BMBT_STARTOFF_BITLEN)));
        ASSERT(!(s->br_blockcount & xfs_mask64hi(64-BMBT_BLOCKCOUNT_BITLEN)));
        ASSERT(!(s->br_startblock & xfs_mask64hi(64-BMBT_STARTBLOCK_BITLEN)));

        put_unaligned_be64(
                ((xfs_bmbt_rec_base_t)extent_flag << 63) |
                 ((xfs_bmbt_rec_base_t)s->br_startoff << 9) |
                 ((xfs_bmbt_rec_base_t)s->br_startblock >> 43), &r->l0);
        put_unaligned_be64(
                ((xfs_bmbt_rec_base_t)s->br_startblock << 21) |
                 ((xfs_bmbt_rec_base_t)s->br_blockcount &
                  (xfs_bmbt_rec_base_t)xfs_mask64lo(21)), &r->l1);
}

/*
 * Convert in-memory form of btree root to on-disk form.
 */
void
xfs_bmbt_to_bmdr(
        struct xfs_mount        *mp,
        struct xfs_btree_block  *rblock,
        int                     rblocklen,
        xfs_bmdr_block_t        *dblock,
        int                     dblocklen)
{
        int                     dmxr;
        xfs_bmbt_key_t          *fkp;
        __be64                  *fpp;
        xfs_bmbt_key_t          *tkp;
        __be64                  *tpp;

        if (xfs_has_crc(mp)) {
                ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_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));
        } else
                ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_MAGIC));
        ASSERT(rblock->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK));
        ASSERT(rblock->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK));
        ASSERT(rblock->bb_level != 0);
        dblock->bb_level = rblock->bb_level;
        dblock->bb_numrecs = rblock->bb_numrecs;
        dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
        fkp = xfs_bmbt_key_addr(mp, rblock, 1);
        tkp = xfs_bmdr_key_addr(dblock, 1);
        fpp = xfs_bmap_broot_ptr_addr(mp, rblock, 1, rblocklen);
        tpp = xfs_bmdr_ptr_addr(dblock, 1, dmxr);
        dmxr = be16_to_cpu(dblock->bb_numrecs);
        memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
        memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
}

STATIC struct xfs_btree_cur *
xfs_bmbt_dup_cursor(
        struct xfs_btree_cur    *cur)
{
        struct xfs_btree_cur    *new;

        new = xfs_bmbt_init_cursor(cur->bc_mp, cur->bc_tp,
                        cur->bc_ino.ip, cur->bc_ino.whichfork);
        new->bc_flags |= (cur->bc_flags &
                (XFS_BTREE_BMBT_INVALID_OWNER | XFS_BTREE_BMBT_WASDEL));
        return new;
}

STATIC void
xfs_bmbt_update_cursor(
        struct xfs_btree_cur    *src,
        struct xfs_btree_cur    *dst)
{
        ASSERT((dst->bc_tp->t_highest_agno != NULLAGNUMBER) ||
               (dst->bc_ino.ip->i_diflags & XFS_DIFLAG_REALTIME));

        dst->bc_bmap.allocated += src->bc_bmap.allocated;
        dst->bc_tp->t_highest_agno = src->bc_tp->t_highest_agno;

        src->bc_bmap.allocated = 0;
}

STATIC int
xfs_bmbt_alloc_block(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_ptr       *start,
        union xfs_btree_ptr             *new,
        int                             *stat)
{
        struct xfs_alloc_arg    args;
        int                     error;

        memset(&args, 0, sizeof(args));
        args.tp = cur->bc_tp;
        args.mp = cur->bc_mp;
        xfs_rmap_ino_bmbt_owner(&args.oinfo, cur->bc_ino.ip->i_ino,
                        cur->bc_ino.whichfork);
        args.minlen = args.maxlen = args.prod = 1;
        args.wasdel = cur->bc_flags & XFS_BTREE_BMBT_WASDEL;
        if (!args.wasdel && args.tp->t_blk_res == 0)
                return -ENOSPC;

        /*
         * If we are coming here from something like unwritten extent
         * conversion, there has been no data extent allocation already done, so
         * we have to ensure that we attempt to locate the entire set of bmbt
         * allocations in the same AG, as xfs_bmapi_write() would have reserved.
         */
        if (cur->bc_tp->t_highest_agno == NULLAGNUMBER)
                args.minleft = xfs_bmapi_minleft(cur->bc_tp, cur->bc_ino.ip,
                                        cur->bc_ino.whichfork);

        error = xfs_alloc_vextent_start_ag(&args, be64_to_cpu(start->l));
        if (error)
                return error;

        if (args.fsbno == NULLFSBLOCK && args.minleft) {
                /*
                 * Could not find an AG with enough free space to satisfy
                 * a full btree split.  Try again and if
                 * successful activate the lowspace algorithm.
                 */
                args.minleft = 0;
                error = xfs_alloc_vextent_start_ag(&args, 0);
                if (error)
                        return error;
                cur->bc_tp->t_flags |= XFS_TRANS_LOWMODE;
        }
        if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
                *stat = 0;
                return 0;
        }

        ASSERT(args.len == 1);
        cur->bc_bmap.allocated++;
        cur->bc_ino.ip->i_nblocks++;
        xfs_trans_log_inode(args.tp, cur->bc_ino.ip, XFS_ILOG_CORE);
        xfs_trans_mod_dquot_byino(args.tp, cur->bc_ino.ip,
                        XFS_TRANS_DQ_BCOUNT, 1L);

        new->l = cpu_to_be64(args.fsbno);

        *stat = 1;
        return 0;
}

STATIC int
xfs_bmbt_free_block(
        struct xfs_btree_cur    *cur,
        struct xfs_buf          *bp)
{
        struct xfs_mount        *mp = cur->bc_mp;
        struct xfs_inode        *ip = cur->bc_ino.ip;
        struct xfs_trans        *tp = cur->bc_tp;
        xfs_fsblock_t           fsbno = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
        struct xfs_owner_info   oinfo;
        int                     error;

        xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, cur->bc_ino.whichfork);
        error = xfs_free_extent_later(cur->bc_tp, fsbno, 1, &oinfo,
                        XFS_AG_RESV_NONE, 0);
        if (error)
                return error;

        ip->i_nblocks--;
        xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
        xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
        return 0;
}

STATIC int
xfs_bmbt_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_bmbt_maxrecs(cur->bc_mp,
                                        ifp->if_broot_bytes, level == 0) / 2;
        }

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

int
xfs_bmbt_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_bmbt_maxrecs(cur->bc_mp,
                                        ifp->if_broot_bytes, level == 0);
        }

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

}

/*
 * Get the maximum records we could store in the on-disk format.
 *
 * For non-root nodes this is equivalent to xfs_bmbt_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_bmbt_get_maxrecs for the root node, too.
 */
STATIC int
xfs_bmbt_get_dmaxrecs(
        struct xfs_btree_cur    *cur,
        int                     level)
{
        if (level != cur->bc_nlevels - 1)
                return cur->bc_mp->m_bmap_dmxr[level != 0];
        return xfs_bmdr_maxrecs(cur->bc_ino.forksize, level == 0);
}

STATIC void
xfs_bmbt_init_key_from_rec(
        union xfs_btree_key             *key,
        const union xfs_btree_rec       *rec)
{
        key->bmbt.br_startoff =
                cpu_to_be64(xfs_bmbt_disk_get_startoff(&rec->bmbt));
}

STATIC void
xfs_bmbt_init_high_key_from_rec(
        union xfs_btree_key             *key,
        const union xfs_btree_rec       *rec)
{
        key->bmbt.br_startoff = cpu_to_be64(
                        xfs_bmbt_disk_get_startoff(&rec->bmbt) +
                        xfs_bmbt_disk_get_blockcount(&rec->bmbt) - 1);
}

STATIC void
xfs_bmbt_init_rec_from_cur(
        struct xfs_btree_cur    *cur,
        union xfs_btree_rec     *rec)
{
        xfs_bmbt_disk_set_all(&rec->bmbt, &cur->bc_rec.b);
}

STATIC int
xfs_bmbt_cmp_key_with_cur(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_key       *key)
{
        return cmp_int(be64_to_cpu(key->bmbt.br_startoff),
                       cur->bc_rec.b.br_startoff);
}

STATIC int
xfs_bmbt_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->bmbt.br_startoff);

        return cmp_int(be64_to_cpu(k1->bmbt.br_startoff),
                       be64_to_cpu(k2->bmbt.br_startoff));
}

static xfs_failaddr_t
xfs_bmbt_verify(
        struct xfs_buf          *bp)
{
        struct xfs_mount        *mp = bp->b_mount;
        struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
        xfs_failaddr_t          fa;
        unsigned int            level;

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

        if (xfs_has_crc(mp)) {
                /*
                 * XXX: need a better way of verifying the owner here. Right now
                 * just make sure there has been one set.
                 */
                fa = xfs_btree_fsblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
                if (fa)
                        return fa;
        }

        /*
         * numrecs and level verification.
         *
         * We don't know what fork we belong to, so just verify that the level
         * is less than the maximum of the two. Later checks will be more
         * precise.
         */
        level = be16_to_cpu(block->bb_level);
        if (level > max(mp->m_bm_maxlevels[0], mp->m_bm_maxlevels[1]))
                return __this_address;

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

static void
xfs_bmbt_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_bmbt_verify(bp);
                if (fa)
                        xfs_verifier_error(bp, -EFSCORRUPTED, fa);
        }

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

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

        fa = xfs_bmbt_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_bmbt_buf_ops = {
        .name = "xfs_bmbt",
        .magic = { cpu_to_be32(XFS_BMAP_MAGIC),
                   cpu_to_be32(XFS_BMAP_CRC_MAGIC) },
        .verify_read = xfs_bmbt_read_verify,
        .verify_write = xfs_bmbt_write_verify,
        .verify_struct = xfs_bmbt_verify,
};


STATIC int
xfs_bmbt_keys_inorder(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_key       *k1,
        const union xfs_btree_key       *k2)
{
        return be64_to_cpu(k1->bmbt.br_startoff) <
                be64_to_cpu(k2->bmbt.br_startoff);
}

STATIC int
xfs_bmbt_recs_inorder(
        struct xfs_btree_cur            *cur,
        const union xfs_btree_rec       *r1,
        const union xfs_btree_rec       *r2)
{
        return xfs_bmbt_disk_get_startoff(&r1->bmbt) +
                xfs_bmbt_disk_get_blockcount(&r1->bmbt) <=
                xfs_bmbt_disk_get_startoff(&r2->bmbt);
}

STATIC enum xbtree_key_contig
xfs_bmbt_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->bmbt.br_startoff);

        return xbtree_key_contig(be64_to_cpu(key1->bmbt.br_startoff),
                                 be64_to_cpu(key2->bmbt.br_startoff));
}

static inline void
xfs_bmbt_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_bmap_broot_ptr_addr(mp, broot, 1, old_size);
        dptr = xfs_bmap_broot_ptr_addr(mp, broot, 1, new_size);
        memmove(dptr, sptr, numrecs * sizeof(xfs_bmbt_ptr_t));
}

/*
 * Reallocate the space for if_broot based on the number of records.  Move the
 * records and pointers in if_broot to fit the new size.  When shrinking this
 * will eliminate holes between the records and pointers created by the caller.
 * When growing this will create holes to be filled in by the caller.
 *
 * The caller must not request to add more records than would fit in the
 * on-disk inode root.  If the if_broot is currently NULL, then if we are
 * adding records, one will be allocated.  The caller must also not request
 * that the number of records go below zero, although it can go to zero.
 *
 * ip -- the inode whose if_broot area is changing
 * whichfork -- which inode fork to change
 * new_numrecs -- the new number of records requested for the if_broot array
 *
 * Returns the incore btree root block.
 */
struct xfs_btree_block *
xfs_bmap_broot_realloc(
        struct xfs_inode        *ip,
        int                     whichfork,
        unsigned int            new_numrecs)
{
        struct xfs_mount        *mp = ip->i_mount;
        struct xfs_ifork        *ifp = xfs_ifork_ptr(ip, whichfork);
        struct xfs_btree_block  *broot;
        unsigned int            new_size;
        unsigned int            old_size = ifp->if_broot_bytes;

        /*
         * Block mapping btrees do not support storing zero records; if this
         * happens, the fork is being changed to FMT_EXTENTS.  Free the broot
         * and get out.
         */
        if (new_numrecs == 0)
                return xfs_broot_realloc(ifp, 0);

        new_size = xfs_bmap_broot_space_calc(mp, 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 shift the pointers to their new
                 * location.  The records don't change location because
                 * they are kept butted up against the btree block header.
                 */
                old_numrecs = xfs_bmbt_maxrecs(mp, old_size, false);
                broot = xfs_broot_realloc(ifp, new_size);
                ASSERT(xfs_bmap_bmdr_space(broot) <=
                        xfs_inode_fork_size(ip, whichfork));
                xfs_bmbt_move_ptrs(mp, broot, old_size, new_size, old_numrecs);
                return broot;
        }

        /*
         * We're reducing, but not totally eliminating, numrecs.  In this case,
         * we are shrinking the if_broot buffer, so it must already exist.
         */
        ASSERT(ifp->if_broot != NULL && old_size > 0 && new_size > 0);

        /*
         * Shrink the btree root by moving the bmbt pointers, since they are
         * not butted up against the btree block header, then reallocating
         * broot.
         */
        xfs_bmbt_move_ptrs(mp, ifp->if_broot, old_size, new_size, new_numrecs);
        broot = xfs_broot_realloc(ifp, new_size);
        ASSERT(xfs_bmap_bmdr_space(broot) <=
               xfs_inode_fork_size(ip, whichfork));
        return broot;
}

static struct xfs_btree_block *
xfs_bmbt_broot_realloc(
        struct xfs_btree_cur    *cur,
        unsigned int            new_numrecs)
{
        return xfs_bmap_broot_realloc(cur->bc_ino.ip, cur->bc_ino.whichfork,
                        new_numrecs);
}

const struct xfs_btree_ops xfs_bmbt_ops = {
        .name                   = "bmap",
        .type                   = XFS_BTREE_TYPE_INODE,

        .rec_len                = sizeof(xfs_bmbt_rec_t),
        .key_len                = sizeof(xfs_bmbt_key_t),
        .ptr_len                = XFS_BTREE_LONG_PTR_LEN,

        .lru_refs               = XFS_BMAP_BTREE_REF,
        .statoff                = XFS_STATS_CALC_INDEX(xs_bmbt_2),

        .dup_cursor             = xfs_bmbt_dup_cursor,
        .update_cursor          = xfs_bmbt_update_cursor,
        .alloc_block            = xfs_bmbt_alloc_block,
        .free_block             = xfs_bmbt_free_block,
        .get_maxrecs            = xfs_bmbt_get_maxrecs,
        .get_minrecs            = xfs_bmbt_get_minrecs,
        .get_dmaxrecs           = xfs_bmbt_get_dmaxrecs,
        .init_key_from_rec      = xfs_bmbt_init_key_from_rec,
        .init_high_key_from_rec = xfs_bmbt_init_high_key_from_rec,
        .init_rec_from_cur      = xfs_bmbt_init_rec_from_cur,
        .cmp_key_with_cur       = xfs_bmbt_cmp_key_with_cur,
        .cmp_two_keys           = xfs_bmbt_cmp_two_keys,
        .buf_ops                = &xfs_bmbt_buf_ops,
        .keys_inorder           = xfs_bmbt_keys_inorder,
        .recs_inorder           = xfs_bmbt_recs_inorder,
        .keys_contiguous        = xfs_bmbt_keys_contiguous,
        .broot_realloc          = xfs_bmbt_broot_realloc,
};

/*
 * Create a new bmap btree cursor.
 *
 * For staging cursors -1 in passed in whichfork.
 */
struct xfs_btree_cur *
xfs_bmbt_init_cursor(
        struct xfs_mount        *mp,
        struct xfs_trans        *tp,
        struct xfs_inode        *ip,
        int                     whichfork)
{
        struct xfs_btree_cur    *cur;
        unsigned int            maxlevels;

        ASSERT(whichfork != XFS_COW_FORK);

        /*
         * The Data fork always has larger maxlevel, so use that for staging
         * cursors.
         */
        switch (whichfork) {
        case XFS_STAGING_FORK:
                maxlevels = mp->m_bm_maxlevels[XFS_DATA_FORK];
                break;
        default:
                maxlevels = mp->m_bm_maxlevels[whichfork];
                break;
        }
        cur = xfs_btree_alloc_cursor(mp, tp, &xfs_bmbt_ops, maxlevels,
                        xfs_bmbt_cur_cache);
        cur->bc_ino.ip = ip;
        cur->bc_ino.whichfork = whichfork;
        cur->bc_bmap.allocated = 0;
        if (whichfork != XFS_STAGING_FORK) {
                struct xfs_ifork        *ifp = xfs_ifork_ptr(ip, whichfork);

                cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
                cur->bc_ino.forksize = xfs_inode_fork_size(ip, whichfork);
        }
        return cur;
}

/* Calculate number of records in a block mapping btree block. */
static inline unsigned int
xfs_bmbt_block_maxrecs(
        unsigned int            blocklen,
        bool                    leaf)
{
        if (leaf)
                return blocklen / sizeof(xfs_bmbt_rec_t);
        return blocklen / (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t));
}

/*
 * Swap in the new inode fork root.  Once we pass this point the newly rebuilt
 * mappings are in place and we have to kill off any old btree blocks.
 */
void
xfs_bmbt_commit_staged_btree(
        struct xfs_btree_cur    *cur,
        struct xfs_trans        *tp,
        int                     whichfork)
{
        struct xbtree_ifakeroot *ifake = cur->bc_ino.ifake;
        struct xfs_ifork        *ifp;
        static const short      brootflag[2] = {XFS_ILOG_DBROOT, XFS_ILOG_ABROOT};
        static const short      extflag[2] = {XFS_ILOG_DEXT, XFS_ILOG_AEXT};
        int                     flags = XFS_ILOG_CORE;

        ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
        ASSERT(whichfork != XFS_COW_FORK);

        /*
         * 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, whichfork);
        xfs_idestroy_fork(ifp);
        memcpy(ifp, ifake->if_fork, sizeof(struct xfs_ifork));

        switch (ifp->if_format) {
        case XFS_DINODE_FMT_EXTENTS:
                flags |= extflag[whichfork];
                break;
        case XFS_DINODE_FMT_BTREE:
                flags |= brootflag[whichfork];
                break;
        default:
                ASSERT(0);
                break;
        }
        xfs_trans_log_inode(tp, cur->bc_ino.ip, flags);
        xfs_btree_commit_ifakeroot(cur, tp, whichfork);
}

/*
 * Calculate number of records in a bmap btree block.
 */
unsigned int
xfs_bmbt_maxrecs(
        struct xfs_mount        *mp,
        unsigned int            blocklen,
        bool                    leaf)
{
        blocklen -= xfs_bmbt_block_len(mp);
        return xfs_bmbt_block_maxrecs(blocklen, leaf);
}

/*
 * Calculate the maximum possible height of the btree that the on-disk format
 * supports. This is used for sizing structures large enough to support every
 * possible configuration of a filesystem that might get mounted.
 */
unsigned int
xfs_bmbt_maxlevels_ondisk(void)
{
        unsigned int            minrecs[2];
        unsigned int            blocklen;

        blocklen = min(XFS_MIN_BLOCKSIZE - XFS_BTREE_SBLOCK_LEN,
                       XFS_MIN_CRC_BLOCKSIZE - XFS_BTREE_SBLOCK_CRC_LEN);

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

        /* One extra level for the inode root. */
        return xfs_btree_compute_maxlevels(minrecs,
                        XFS_MAX_EXTCNT_DATA_FORK_LARGE) + 1;
}

/*
 * Calculate number of records in a bmap btree inode root.
 */
int
xfs_bmdr_maxrecs(
        int                     blocklen,
        int                     leaf)
{
        blocklen -= sizeof(xfs_bmdr_block_t);

        if (leaf)
                return blocklen / sizeof(xfs_bmdr_rec_t);
        return blocklen / (sizeof(xfs_bmdr_key_t) + sizeof(xfs_bmdr_ptr_t));
}

/*
 * Change the owner of a btree format fork fo the inode passed in. Change it to
 * the owner of that is passed in so that we can change owners before or after
 * we switch forks between inodes. The operation that the caller is doing will
 * determine whether is needs to change owner before or after the switch.
 *
 * For demand paged transactional modification, the fork switch should be done
 * after reading in all the blocks, modifying them and pinning them in the
 * transaction. For modification when the buffers are already pinned in memory,
 * the fork switch can be done before changing the owner as we won't need to
 * validate the owner until the btree buffers are unpinned and writes can occur
 * again.
 *
 * For recovery based ownership change, there is no transactional context and
 * so a buffer list must be supplied so that we can record the buffers that we
 * modified for the caller to issue IO on.
 */
int
xfs_bmbt_change_owner(
        struct xfs_trans        *tp,
        struct xfs_inode        *ip,
        int                     whichfork,
        xfs_ino_t               new_owner,
        struct list_head        *buffer_list)
{
        struct xfs_btree_cur    *cur;
        int                     error;

        ASSERT(tp || buffer_list);
        ASSERT(!(tp && buffer_list));
        ASSERT(xfs_ifork_ptr(ip, whichfork)->if_format == XFS_DINODE_FMT_BTREE);

        cur = xfs_bmbt_init_cursor(ip->i_mount, tp, ip, whichfork);
        cur->bc_flags |= XFS_BTREE_BMBT_INVALID_OWNER;

        error = xfs_btree_change_owner(cur, new_owner, buffer_list);
        xfs_btree_del_cursor(cur, error);
        return error;
}

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

int __init
xfs_bmbt_init_cur_cache(void)
{
        xfs_bmbt_cur_cache = kmem_cache_create("xfs_bmbt_cur",
                        xfs_btree_cur_sizeof(xfs_bmbt_maxlevels_ondisk()),
                        0, 0, NULL);

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

void
xfs_bmbt_destroy_cur_cache(void)
{
        kmem_cache_destroy(xfs_bmbt_cur_cache);
        xfs_bmbt_cur_cache = NULL;
}