fs/xfs/libxfs/xfs_bmap_btree.c

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