linux/fs/xfs/libxfs/xfs_bmap_btree.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
   4 * All Rights Reserved.
   5 */
   6#include "xfs.h"
   7#include "xfs_fs.h"
   8#include "xfs_shared.h"
   9#include "xfs_format.h"
  10#include "xfs_log_format.h"
  11#include "xfs_trans_resv.h"
  12#include "xfs_bit.h"
  13#include "xfs_mount.h"
  14#include "xfs_inode.h"
  15#include "xfs_trans.h"
  16#include "xfs_alloc.h"
  17#include "xfs_btree.h"
  18#include "xfs_bmap_btree.h"
  19#include "xfs_bmap.h"
  20#include "xfs_error.h"
  21#include "xfs_quota.h"
  22#include "xfs_trace.h"
  23#include "xfs_rmap.h"
  24
  25/*
  26 * Convert on-disk form of btree root to in-memory form.
  27 */
  28void
  29xfs_bmdr_to_bmbt(
  30        struct xfs_inode        *ip,
  31        xfs_bmdr_block_t        *dblock,
  32        int                     dblocklen,
  33        struct xfs_btree_block  *rblock,
  34        int                     rblocklen)
  35{
  36        struct xfs_mount        *mp = ip->i_mount;
  37        int                     dmxr;
  38        xfs_bmbt_key_t          *fkp;
  39        __be64                  *fpp;
  40        xfs_bmbt_key_t          *tkp;
  41        __be64                  *tpp;
  42
  43        xfs_btree_init_block_int(mp, rblock, XFS_BUF_DADDR_NULL,
  44                                 XFS_BTNUM_BMAP, 0, 0, ip->i_ino,
  45                                 XFS_BTREE_LONG_PTRS);
  46        rblock->bb_level = dblock->bb_level;
  47        ASSERT(be16_to_cpu(rblock->bb_level) > 0);
  48        rblock->bb_numrecs = dblock->bb_numrecs;
  49        dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
  50        fkp = XFS_BMDR_KEY_ADDR(dblock, 1);
  51        tkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
  52        fpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
  53        tpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
  54        dmxr = be16_to_cpu(dblock->bb_numrecs);
  55        memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
  56        memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
  57}
  58
  59void
  60xfs_bmbt_disk_get_all(
  61        struct xfs_bmbt_rec     *rec,
  62        struct xfs_bmbt_irec    *irec)
  63{
  64        uint64_t                l0 = get_unaligned_be64(&rec->l0);
  65        uint64_t                l1 = get_unaligned_be64(&rec->l1);
  66
  67        irec->br_startoff = (l0 & xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
  68        irec->br_startblock = ((l0 & xfs_mask64lo(9)) << 43) | (l1 >> 21);
  69        irec->br_blockcount = l1 & xfs_mask64lo(21);
  70        if (l0 >> (64 - BMBT_EXNTFLAG_BITLEN))
  71                irec->br_state = XFS_EXT_UNWRITTEN;
  72        else
  73                irec->br_state = XFS_EXT_NORM;
  74}
  75
  76/*
  77 * Extract the blockcount field from an on disk bmap extent record.
  78 */
  79xfs_filblks_t
  80xfs_bmbt_disk_get_blockcount(
  81        xfs_bmbt_rec_t  *r)
  82{
  83        return (xfs_filblks_t)(be64_to_cpu(r->l1) & xfs_mask64lo(21));
  84}
  85
  86/*
  87 * Extract the startoff field from a disk format bmap extent record.
  88 */
  89xfs_fileoff_t
  90xfs_bmbt_disk_get_startoff(
  91        xfs_bmbt_rec_t  *r)
  92{
  93        return ((xfs_fileoff_t)be64_to_cpu(r->l0) &
  94                 xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
  95}
  96
  97/*
  98 * Set all the fields in a bmap extent record from the uncompressed form.
  99 */
 100void
 101xfs_bmbt_disk_set_all(
 102        struct xfs_bmbt_rec     *r,
 103        struct xfs_bmbt_irec    *s)
 104{
 105        int                     extent_flag = (s->br_state != XFS_EXT_NORM);
 106
 107        ASSERT(s->br_state == XFS_EXT_NORM || s->br_state == XFS_EXT_UNWRITTEN);
 108        ASSERT(!(s->br_startoff & xfs_mask64hi(64-BMBT_STARTOFF_BITLEN)));
 109        ASSERT(!(s->br_blockcount & xfs_mask64hi(64-BMBT_BLOCKCOUNT_BITLEN)));
 110        ASSERT(!(s->br_startblock & xfs_mask64hi(64-BMBT_STARTBLOCK_BITLEN)));
 111
 112        put_unaligned_be64(
 113                ((xfs_bmbt_rec_base_t)extent_flag << 63) |
 114                 ((xfs_bmbt_rec_base_t)s->br_startoff << 9) |
 115                 ((xfs_bmbt_rec_base_t)s->br_startblock >> 43), &r->l0);
 116        put_unaligned_be64(
 117                ((xfs_bmbt_rec_base_t)s->br_startblock << 21) |
 118                 ((xfs_bmbt_rec_base_t)s->br_blockcount &
 119                  (xfs_bmbt_rec_base_t)xfs_mask64lo(21)), &r->l1);
 120}
 121
 122/*
 123 * Convert in-memory form of btree root to on-disk form.
 124 */
 125void
 126xfs_bmbt_to_bmdr(
 127        struct xfs_mount        *mp,
 128        struct xfs_btree_block  *rblock,
 129        int                     rblocklen,
 130        xfs_bmdr_block_t        *dblock,
 131        int                     dblocklen)
 132{
 133        int                     dmxr;
 134        xfs_bmbt_key_t          *fkp;
 135        __be64                  *fpp;
 136        xfs_bmbt_key_t          *tkp;
 137        __be64                  *tpp;
 138
 139        if (xfs_sb_version_hascrc(&mp->m_sb)) {
 140                ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_CRC_MAGIC));
 141                ASSERT(uuid_equal(&rblock->bb_u.l.bb_uuid,
 142                       &mp->m_sb.sb_meta_uuid));
 143                ASSERT(rblock->bb_u.l.bb_blkno ==
 144                       cpu_to_be64(XFS_BUF_DADDR_NULL));
 145        } else
 146                ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_MAGIC));
 147        ASSERT(rblock->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK));
 148        ASSERT(rblock->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK));
 149        ASSERT(rblock->bb_level != 0);
 150        dblock->bb_level = rblock->bb_level;
 151        dblock->bb_numrecs = rblock->bb_numrecs;
 152        dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
 153        fkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
 154        tkp = XFS_BMDR_KEY_ADDR(dblock, 1);
 155        fpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
 156        tpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
 157        dmxr = be16_to_cpu(dblock->bb_numrecs);
 158        memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
 159        memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
 160}
 161
 162STATIC struct xfs_btree_cur *
 163xfs_bmbt_dup_cursor(
 164        struct xfs_btree_cur    *cur)
 165{
 166        struct xfs_btree_cur    *new;
 167
 168        new = xfs_bmbt_init_cursor(cur->bc_mp, cur->bc_tp,
 169                        cur->bc_ino.ip, cur->bc_ino.whichfork);
 170
 171        /*
 172         * Copy the firstblock, dfops, and flags values,
 173         * since init cursor doesn't get them.
 174         */
 175        new->bc_ino.flags = cur->bc_ino.flags;
 176
 177        return new;
 178}
 179
 180STATIC void
 181xfs_bmbt_update_cursor(
 182        struct xfs_btree_cur    *src,
 183        struct xfs_btree_cur    *dst)
 184{
 185        ASSERT((dst->bc_tp->t_firstblock != NULLFSBLOCK) ||
 186               (dst->bc_ino.ip->i_d.di_flags & XFS_DIFLAG_REALTIME));
 187
 188        dst->bc_ino.allocated += src->bc_ino.allocated;
 189        dst->bc_tp->t_firstblock = src->bc_tp->t_firstblock;
 190
 191        src->bc_ino.allocated = 0;
 192}
 193
 194STATIC int
 195xfs_bmbt_alloc_block(
 196        struct xfs_btree_cur    *cur,
 197        union xfs_btree_ptr     *start,
 198        union xfs_btree_ptr     *new,
 199        int                     *stat)
 200{
 201        xfs_alloc_arg_t         args;           /* block allocation args */
 202        int                     error;          /* error return value */
 203
 204        memset(&args, 0, sizeof(args));
 205        args.tp = cur->bc_tp;
 206        args.mp = cur->bc_mp;
 207        args.fsbno = cur->bc_tp->t_firstblock;
 208        xfs_rmap_ino_bmbt_owner(&args.oinfo, cur->bc_ino.ip->i_ino,
 209                        cur->bc_ino.whichfork);
 210
 211        if (args.fsbno == NULLFSBLOCK) {
 212                args.fsbno = be64_to_cpu(start->l);
 213                args.type = XFS_ALLOCTYPE_START_BNO;
 214                /*
 215                 * Make sure there is sufficient room left in the AG to
 216                 * complete a full tree split for an extent insert.  If
 217                 * we are converting the middle part of an extent then
 218                 * we may need space for two tree splits.
 219                 *
 220                 * We are relying on the caller to make the correct block
 221                 * reservation for this operation to succeed.  If the
 222                 * reservation amount is insufficient then we may fail a
 223                 * block allocation here and corrupt the filesystem.
 224                 */
 225                args.minleft = args.tp->t_blk_res;
 226        } else if (cur->bc_tp->t_flags & XFS_TRANS_LOWMODE) {
 227                args.type = XFS_ALLOCTYPE_START_BNO;
 228        } else {
 229                args.type = XFS_ALLOCTYPE_NEAR_BNO;
 230        }
 231
 232        args.minlen = args.maxlen = args.prod = 1;
 233        args.wasdel = cur->bc_ino.flags & XFS_BTCUR_BMBT_WASDEL;
 234        if (!args.wasdel && args.tp->t_blk_res == 0) {
 235                error = -ENOSPC;
 236                goto error0;
 237        }
 238        error = xfs_alloc_vextent(&args);
 239        if (error)
 240                goto error0;
 241
 242        if (args.fsbno == NULLFSBLOCK && args.minleft) {
 243                /*
 244                 * Could not find an AG with enough free space to satisfy
 245                 * a full btree split.  Try again and if
 246                 * successful activate the lowspace algorithm.
 247                 */
 248                args.fsbno = 0;
 249                args.type = XFS_ALLOCTYPE_FIRST_AG;
 250                error = xfs_alloc_vextent(&args);
 251                if (error)
 252                        goto error0;
 253                cur->bc_tp->t_flags |= XFS_TRANS_LOWMODE;
 254        }
 255        if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
 256                *stat = 0;
 257                return 0;
 258        }
 259
 260        ASSERT(args.len == 1);
 261        cur->bc_tp->t_firstblock = args.fsbno;
 262        cur->bc_ino.allocated++;
 263        cur->bc_ino.ip->i_d.di_nblocks++;
 264        xfs_trans_log_inode(args.tp, cur->bc_ino.ip, XFS_ILOG_CORE);
 265        xfs_trans_mod_dquot_byino(args.tp, cur->bc_ino.ip,
 266                        XFS_TRANS_DQ_BCOUNT, 1L);
 267
 268        new->l = cpu_to_be64(args.fsbno);
 269
 270        *stat = 1;
 271        return 0;
 272
 273 error0:
 274        return error;
 275}
 276
 277STATIC int
 278xfs_bmbt_free_block(
 279        struct xfs_btree_cur    *cur,
 280        struct xfs_buf          *bp)
 281{
 282        struct xfs_mount        *mp = cur->bc_mp;
 283        struct xfs_inode        *ip = cur->bc_ino.ip;
 284        struct xfs_trans        *tp = cur->bc_tp;
 285        xfs_fsblock_t           fsbno = XFS_DADDR_TO_FSB(mp, XFS_BUF_ADDR(bp));
 286        struct xfs_owner_info   oinfo;
 287
 288        xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, cur->bc_ino.whichfork);
 289        xfs_bmap_add_free(cur->bc_tp, fsbno, 1, &oinfo);
 290        ip->i_d.di_nblocks--;
 291
 292        xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 293        xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
 294        return 0;
 295}
 296
 297STATIC int
 298xfs_bmbt_get_minrecs(
 299        struct xfs_btree_cur    *cur,
 300        int                     level)
 301{
 302        if (level == cur->bc_nlevels - 1) {
 303                struct xfs_ifork        *ifp;
 304
 305                ifp = XFS_IFORK_PTR(cur->bc_ino.ip,
 306                                    cur->bc_ino.whichfork);
 307
 308                return xfs_bmbt_maxrecs(cur->bc_mp,
 309                                        ifp->if_broot_bytes, level == 0) / 2;
 310        }
 311
 312        return cur->bc_mp->m_bmap_dmnr[level != 0];
 313}
 314
 315int
 316xfs_bmbt_get_maxrecs(
 317        struct xfs_btree_cur    *cur,
 318        int                     level)
 319{
 320        if (level == cur->bc_nlevels - 1) {
 321                struct xfs_ifork        *ifp;
 322
 323                ifp = XFS_IFORK_PTR(cur->bc_ino.ip,
 324                                    cur->bc_ino.whichfork);
 325
 326                return xfs_bmbt_maxrecs(cur->bc_mp,
 327                                        ifp->if_broot_bytes, level == 0);
 328        }
 329
 330        return cur->bc_mp->m_bmap_dmxr[level != 0];
 331
 332}
 333
 334/*
 335 * Get the maximum records we could store in the on-disk format.
 336 *
 337 * For non-root nodes this is equivalent to xfs_bmbt_get_maxrecs, but
 338 * for the root node this checks the available space in the dinode fork
 339 * so that we can resize the in-memory buffer to match it.  After a
 340 * resize to the maximum size this function returns the same value
 341 * as xfs_bmbt_get_maxrecs for the root node, too.
 342 */
 343STATIC int
 344xfs_bmbt_get_dmaxrecs(
 345        struct xfs_btree_cur    *cur,
 346        int                     level)
 347{
 348        if (level != cur->bc_nlevels - 1)
 349                return cur->bc_mp->m_bmap_dmxr[level != 0];
 350        return xfs_bmdr_maxrecs(cur->bc_ino.forksize, level == 0);
 351}
 352
 353STATIC void
 354xfs_bmbt_init_key_from_rec(
 355        union xfs_btree_key     *key,
 356        union xfs_btree_rec     *rec)
 357{
 358        key->bmbt.br_startoff =
 359                cpu_to_be64(xfs_bmbt_disk_get_startoff(&rec->bmbt));
 360}
 361
 362STATIC void
 363xfs_bmbt_init_high_key_from_rec(
 364        union xfs_btree_key     *key,
 365        union xfs_btree_rec     *rec)
 366{
 367        key->bmbt.br_startoff = cpu_to_be64(
 368                        xfs_bmbt_disk_get_startoff(&rec->bmbt) +
 369                        xfs_bmbt_disk_get_blockcount(&rec->bmbt) - 1);
 370}
 371
 372STATIC void
 373xfs_bmbt_init_rec_from_cur(
 374        struct xfs_btree_cur    *cur,
 375        union xfs_btree_rec     *rec)
 376{
 377        xfs_bmbt_disk_set_all(&rec->bmbt, &cur->bc_rec.b);
 378}
 379
 380STATIC void
 381xfs_bmbt_init_ptr_from_cur(
 382        struct xfs_btree_cur    *cur,
 383        union xfs_btree_ptr     *ptr)
 384{
 385        ptr->l = 0;
 386}
 387
 388STATIC int64_t
 389xfs_bmbt_key_diff(
 390        struct xfs_btree_cur    *cur,
 391        union xfs_btree_key     *key)
 392{
 393        return (int64_t)be64_to_cpu(key->bmbt.br_startoff) -
 394                                      cur->bc_rec.b.br_startoff;
 395}
 396
 397STATIC int64_t
 398xfs_bmbt_diff_two_keys(
 399        struct xfs_btree_cur    *cur,
 400        union xfs_btree_key     *k1,
 401        union xfs_btree_key     *k2)
 402{
 403        uint64_t                a = be64_to_cpu(k1->bmbt.br_startoff);
 404        uint64_t                b = be64_to_cpu(k2->bmbt.br_startoff);
 405
 406        /*
 407         * Note: This routine previously casted a and b to int64 and subtracted
 408         * them to generate a result.  This lead to problems if b was the
 409         * "maximum" key value (all ones) being signed incorrectly, hence this
 410         * somewhat less efficient version.
 411         */
 412        if (a > b)
 413                return 1;
 414        if (b > a)
 415                return -1;
 416        return 0;
 417}
 418
 419static xfs_failaddr_t
 420xfs_bmbt_verify(
 421        struct xfs_buf          *bp)
 422{
 423        struct xfs_mount        *mp = bp->b_mount;
 424        struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
 425        xfs_failaddr_t          fa;
 426        unsigned int            level;
 427
 428        if (!xfs_verify_magic(bp, block->bb_magic))
 429                return __this_address;
 430
 431        if (xfs_sb_version_hascrc(&mp->m_sb)) {
 432                /*
 433                 * XXX: need a better way of verifying the owner here. Right now
 434                 * just make sure there has been one set.
 435                 */
 436                fa = xfs_btree_lblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
 437                if (fa)
 438                        return fa;
 439        }
 440
 441        /*
 442         * numrecs and level verification.
 443         *
 444         * We don't know what fork we belong to, so just verify that the level
 445         * is less than the maximum of the two. Later checks will be more
 446         * precise.
 447         */
 448        level = be16_to_cpu(block->bb_level);
 449        if (level > max(mp->m_bm_maxlevels[0], mp->m_bm_maxlevels[1]))
 450                return __this_address;
 451
 452        return xfs_btree_lblock_verify(bp, mp->m_bmap_dmxr[level != 0]);
 453}
 454
 455static void
 456xfs_bmbt_read_verify(
 457        struct xfs_buf  *bp)
 458{
 459        xfs_failaddr_t  fa;
 460
 461        if (!xfs_btree_lblock_verify_crc(bp))
 462                xfs_verifier_error(bp, -EFSBADCRC, __this_address);
 463        else {
 464                fa = xfs_bmbt_verify(bp);
 465                if (fa)
 466                        xfs_verifier_error(bp, -EFSCORRUPTED, fa);
 467        }
 468
 469        if (bp->b_error)
 470                trace_xfs_btree_corrupt(bp, _RET_IP_);
 471}
 472
 473static void
 474xfs_bmbt_write_verify(
 475        struct xfs_buf  *bp)
 476{
 477        xfs_failaddr_t  fa;
 478
 479        fa = xfs_bmbt_verify(bp);
 480        if (fa) {
 481                trace_xfs_btree_corrupt(bp, _RET_IP_);
 482                xfs_verifier_error(bp, -EFSCORRUPTED, fa);
 483                return;
 484        }
 485        xfs_btree_lblock_calc_crc(bp);
 486}
 487
 488const struct xfs_buf_ops xfs_bmbt_buf_ops = {
 489        .name = "xfs_bmbt",
 490        .magic = { cpu_to_be32(XFS_BMAP_MAGIC),
 491                   cpu_to_be32(XFS_BMAP_CRC_MAGIC) },
 492        .verify_read = xfs_bmbt_read_verify,
 493        .verify_write = xfs_bmbt_write_verify,
 494        .verify_struct = xfs_bmbt_verify,
 495};
 496
 497
 498STATIC int
 499xfs_bmbt_keys_inorder(
 500        struct xfs_btree_cur    *cur,
 501        union xfs_btree_key     *k1,
 502        union xfs_btree_key     *k2)
 503{
 504        return be64_to_cpu(k1->bmbt.br_startoff) <
 505                be64_to_cpu(k2->bmbt.br_startoff);
 506}
 507
 508STATIC int
 509xfs_bmbt_recs_inorder(
 510        struct xfs_btree_cur    *cur,
 511        union xfs_btree_rec     *r1,
 512        union xfs_btree_rec     *r2)
 513{
 514        return xfs_bmbt_disk_get_startoff(&r1->bmbt) +
 515                xfs_bmbt_disk_get_blockcount(&r1->bmbt) <=
 516                xfs_bmbt_disk_get_startoff(&r2->bmbt);
 517}
 518
 519static const struct xfs_btree_ops xfs_bmbt_ops = {
 520        .rec_len                = sizeof(xfs_bmbt_rec_t),
 521        .key_len                = sizeof(xfs_bmbt_key_t),
 522
 523        .dup_cursor             = xfs_bmbt_dup_cursor,
 524        .update_cursor          = xfs_bmbt_update_cursor,
 525        .alloc_block            = xfs_bmbt_alloc_block,
 526        .free_block             = xfs_bmbt_free_block,
 527        .get_maxrecs            = xfs_bmbt_get_maxrecs,
 528        .get_minrecs            = xfs_bmbt_get_minrecs,
 529        .get_dmaxrecs           = xfs_bmbt_get_dmaxrecs,
 530        .init_key_from_rec      = xfs_bmbt_init_key_from_rec,
 531        .init_high_key_from_rec = xfs_bmbt_init_high_key_from_rec,
 532        .init_rec_from_cur      = xfs_bmbt_init_rec_from_cur,
 533        .init_ptr_from_cur      = xfs_bmbt_init_ptr_from_cur,
 534        .key_diff               = xfs_bmbt_key_diff,
 535        .diff_two_keys          = xfs_bmbt_diff_two_keys,
 536        .buf_ops                = &xfs_bmbt_buf_ops,
 537        .keys_inorder           = xfs_bmbt_keys_inorder,
 538        .recs_inorder           = xfs_bmbt_recs_inorder,
 539};
 540
 541/*
 542 * Allocate a new bmap btree cursor.
 543 */
 544struct xfs_btree_cur *                          /* new bmap btree cursor */
 545xfs_bmbt_init_cursor(
 546        struct xfs_mount        *mp,            /* file system mount point */
 547        struct xfs_trans        *tp,            /* transaction pointer */
 548        struct xfs_inode        *ip,            /* inode owning the btree */
 549        int                     whichfork)      /* data or attr fork */
 550{
 551        struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, whichfork);
 552        struct xfs_btree_cur    *cur;
 553        ASSERT(whichfork != XFS_COW_FORK);
 554
 555        cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
 556
 557        cur->bc_tp = tp;
 558        cur->bc_mp = mp;
 559        cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
 560        cur->bc_btnum = XFS_BTNUM_BMAP;
 561        cur->bc_blocklog = mp->m_sb.sb_blocklog;
 562        cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_bmbt_2);
 563
 564        cur->bc_ops = &xfs_bmbt_ops;
 565        cur->bc_flags = XFS_BTREE_LONG_PTRS | XFS_BTREE_ROOT_IN_INODE;
 566        if (xfs_sb_version_hascrc(&mp->m_sb))
 567                cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
 568
 569        cur->bc_ino.forksize = XFS_IFORK_SIZE(ip, whichfork);
 570        cur->bc_ino.ip = ip;
 571        cur->bc_ino.allocated = 0;
 572        cur->bc_ino.flags = 0;
 573        cur->bc_ino.whichfork = whichfork;
 574
 575        return cur;
 576}
 577
 578/*
 579 * Calculate number of records in a bmap btree block.
 580 */
 581int
 582xfs_bmbt_maxrecs(
 583        struct xfs_mount        *mp,
 584        int                     blocklen,
 585        int                     leaf)
 586{
 587        blocklen -= XFS_BMBT_BLOCK_LEN(mp);
 588
 589        if (leaf)
 590                return blocklen / sizeof(xfs_bmbt_rec_t);
 591        return blocklen / (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t));
 592}
 593
 594/*
 595 * Calculate number of records in a bmap btree inode root.
 596 */
 597int
 598xfs_bmdr_maxrecs(
 599        int                     blocklen,
 600        int                     leaf)
 601{
 602        blocklen -= sizeof(xfs_bmdr_block_t);
 603
 604        if (leaf)
 605                return blocklen / sizeof(xfs_bmdr_rec_t);
 606        return blocklen / (sizeof(xfs_bmdr_key_t) + sizeof(xfs_bmdr_ptr_t));
 607}
 608
 609/*
 610 * Change the owner of a btree format fork fo the inode passed in. Change it to
 611 * the owner of that is passed in so that we can change owners before or after
 612 * we switch forks between inodes. The operation that the caller is doing will
 613 * determine whether is needs to change owner before or after the switch.
 614 *
 615 * For demand paged transactional modification, the fork switch should be done
 616 * after reading in all the blocks, modifying them and pinning them in the
 617 * transaction. For modification when the buffers are already pinned in memory,
 618 * the fork switch can be done before changing the owner as we won't need to
 619 * validate the owner until the btree buffers are unpinned and writes can occur
 620 * again.
 621 *
 622 * For recovery based ownership change, there is no transactional context and
 623 * so a buffer list must be supplied so that we can record the buffers that we
 624 * modified for the caller to issue IO on.
 625 */
 626int
 627xfs_bmbt_change_owner(
 628        struct xfs_trans        *tp,
 629        struct xfs_inode        *ip,
 630        int                     whichfork,
 631        xfs_ino_t               new_owner,
 632        struct list_head        *buffer_list)
 633{
 634        struct xfs_btree_cur    *cur;
 635        int                     error;
 636
 637        ASSERT(tp || buffer_list);
 638        ASSERT(!(tp && buffer_list));
 639        ASSERT(XFS_IFORK_PTR(ip, whichfork)->if_format == XFS_DINODE_FMT_BTREE);
 640
 641        cur = xfs_bmbt_init_cursor(ip->i_mount, tp, ip, whichfork);
 642        if (!cur)
 643                return -ENOMEM;
 644        cur->bc_ino.flags |= XFS_BTCUR_BMBT_INVALID_OWNER;
 645
 646        error = xfs_btree_change_owner(cur, new_owner, buffer_list);
 647        xfs_btree_del_cursor(cur, error);
 648        return error;
 649}
 650
 651/* Calculate the bmap btree size for some records. */
 652unsigned long long
 653xfs_bmbt_calc_size(
 654        struct xfs_mount        *mp,
 655        unsigned long long      len)
 656{
 657        return xfs_btree_calc_size(mp->m_bmap_dmnr, len);
 658}
 659