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.flags = cur->bc_private.b.flags;
 179
 180         return new;
 181 }
 182
 183 STATIC void
 184 xfs_bmbt_update_cursor(
 185         struct xfs_btree_cur    *src,
 186         struct xfs_btree_cur    *dst)
 187 {
 188         ASSERT((dst->bc_tp->t_firstblock != NULLFSBLOCK) ||
 189                (dst->bc_private.b.ip->i_d.di_flags & XFS_DIFLAG_REALTIME));
 190
 191         dst->bc_private.b.allocated += src->bc_private.b.allocated;
 192         dst->bc_tp->t_firstblock = src->bc_tp->t_firstblock;
 193
 194         src->bc_private.b.allocated = 0;
 195 }
 196
 197 STATIC int
 198 xfs_bmbt_alloc_block(
 199         struct xfs_btree_cur    *cur,
 200         union xfs_btree_ptr     *start,
 201         union xfs_btree_ptr     *new,
 202         int                     *stat)
 203 {
 204         xfs_alloc_arg_t         args;           /* block allocation args */
 205         int                     error;          /* error return value */
 206
 207         memset(&args, 0, sizeof(args));
 208         args.tp = cur->bc_tp;
 209         args.mp = cur->bc_mp;
 210         args.fsbno = cur->bc_tp->t_firstblock;
 211         xfs_rmap_ino_bmbt_owner(&args.oinfo, cur->bc_private.b.ip->i_ino,
 212                         cur->bc_private.b.whichfork);
 213
 214         if (args.fsbno == NULLFSBLOCK) {
 215                 args.fsbno = be64_to_cpu(start->l);
 216                 args.type = XFS_ALLOCTYPE_START_BNO;
 217                 /*
 218                  * Make sure there is sufficient room left in the AG to
 219                  * complete a full tree split for an extent insert.  If
 220                  * we are converting the middle part of an extent then
 221                  * we may need space for two tree splits.
 222                  *
 223                  * We are relying on the caller to make the correct block
 224                  * reservation for this operation to succeed.  If the
 225                  * reservation amount is insufficient then we may fail a
 226                  * block allocation here and corrupt the filesystem.
 227                  */
 228                 args.minleft = args.tp->t_blk_res;
 229         } else if (cur->bc_tp->t_flags & XFS_TRANS_LOWMODE) {
 230                 args.type = XFS_ALLOCTYPE_START_BNO;
 231         } else {
 232                 args.type = XFS_ALLOCTYPE_NEAR_BNO;
 233         }
 234
 235         args.minlen = args.maxlen = args.prod = 1;
 236         args.wasdel = cur->bc_private.b.flags & XFS_BTCUR_BPRV_WASDEL;
 237         if (!args.wasdel && args.tp->t_blk_res == 0) {
 238                 error = -ENOSPC;
 239                 goto error0;
 240         }
 241         error = xfs_alloc_vextent(&args);
 242         if (error)
 243                 goto error0;
 244
 245         if (args.fsbno == NULLFSBLOCK && args.minleft) {
 246                 /*
 247                  * Could not find an AG with enough free space to satisfy
 248                  * a full btree split.  Try again and if
 249                  * successful activate the lowspace algorithm.
 250                  */
 251                 args.fsbno = 0;
 252                 args.type = XFS_ALLOCTYPE_FIRST_AG;
 253                 error = xfs_alloc_vextent(&args);
 254                 if (error)
 255                         goto error0;
 256                 cur->bc_tp->t_flags |= XFS_TRANS_LOWMODE;
 257         }
 258         if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
 259                 *stat = 0;
 260                 return 0;
 261         }
 262
 263         ASSERT(args.len == 1);
 264         cur->bc_tp->t_firstblock = args.fsbno;
 265         cur->bc_private.b.allocated++;
 266         cur->bc_private.b.ip->i_d.di_nblocks++;
 267         xfs_trans_log_inode(args.tp, cur->bc_private.b.ip, XFS_ILOG_CORE);
 268         xfs_trans_mod_dquot_byino(args.tp, cur->bc_private.b.ip,
 269                         XFS_TRANS_DQ_BCOUNT, 1L);
 270
 271         new->l = cpu_to_be64(args.fsbno);
 272
 273         *stat = 1;
 274         return 0;
 275
 276  error0:
 277         return error;
 278 }
 279
 280 STATIC int
 281 xfs_bmbt_free_block(
 282         struct xfs_btree_cur    *cur,
 283         struct xfs_buf          *bp)
 284 {
 285         struct xfs_mount        *mp = cur->bc_mp;
 286         struct xfs_inode        *ip = cur->bc_private.b.ip;
 287         struct xfs_trans        *tp = cur->bc_tp;
 288         xfs_fsblock_t           fsbno = XFS_DADDR_TO_FSB(mp, XFS_BUF_ADDR(bp));
 289         struct xfs_owner_info   oinfo;
 290
 291         xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, cur->bc_private.b.whichfork);
 292         xfs_bmap_add_free(cur->bc_tp, fsbno, 1, &oinfo);
 293         ip->i_d.di_nblocks--;
 294
 295         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 296         xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
 297         return 0;
 298 }
 299
 300 STATIC int
 301 xfs_bmbt_get_minrecs(
 302         struct xfs_btree_cur    *cur,
 303         int                     level)
 304 {
 305         if (level == cur->bc_nlevels - 1) {
 306                 struct xfs_ifork        *ifp;
 307
 308                 ifp = XFS_IFORK_PTR(cur->bc_private.b.ip,
 309                                     cur->bc_private.b.whichfork);
 310
 311                 return xfs_bmbt_maxrecs(cur->bc_mp,
 312                                         ifp->if_broot_bytes, level == 0) / 2;
 313         }
 314
 315         return cur->bc_mp->m_bmap_dmnr[level != 0];
 316 }
 317
 318 int
 319 xfs_bmbt_get_maxrecs(
 320         struct xfs_btree_cur    *cur,
 321         int                     level)
 322 {
 323         if (level == cur->bc_nlevels - 1) {
 324                 struct xfs_ifork        *ifp;
 325
 326                 ifp = XFS_IFORK_PTR(cur->bc_private.b.ip,
 327                                     cur->bc_private.b.whichfork);
 328
 329                 return xfs_bmbt_maxrecs(cur->bc_mp,
 330                                         ifp->if_broot_bytes, level == 0);
 331         }
 332
 333         return cur->bc_mp->m_bmap_dmxr[level != 0];
 334
 335 }
 336
 337 /*
 338  * Get the maximum records we could store in the on-disk format.
 339  *
 340  * For non-root nodes this is equivalent to xfs_bmbt_get_maxrecs, but
 341  * for the root node this checks the available space in the dinode fork
 342  * so that we can resize the in-memory buffer to match it.  After a
 343  * resize to the maximum size this function returns the same value
 344  * as xfs_bmbt_get_maxrecs for the root node, too.
 345  */
 346 STATIC int
 347 xfs_bmbt_get_dmaxrecs(
 348         struct xfs_btree_cur    *cur,
 349         int                     level)
 350 {
 351         if (level != cur->bc_nlevels - 1)
 352                 return cur->bc_mp->m_bmap_dmxr[level != 0];
 353         return xfs_bmdr_maxrecs(cur->bc_private.b.forksize, level == 0);
 354 }
 355
 356 STATIC void
 357 xfs_bmbt_init_key_from_rec(
 358         union xfs_btree_key     *key,
 359         union xfs_btree_rec     *rec)
 360 {
 361         key->bmbt.br_startoff =
 362                 cpu_to_be64(xfs_bmbt_disk_get_startoff(&rec->bmbt));
 363 }
 364
 365 STATIC void
 366 xfs_bmbt_init_high_key_from_rec(
 367         union xfs_btree_key     *key,
 368         union xfs_btree_rec     *rec)
 369 {
 370         key->bmbt.br_startoff = cpu_to_be64(
 371                         xfs_bmbt_disk_get_startoff(&rec->bmbt) +
 372                         xfs_bmbt_disk_get_blockcount(&rec->bmbt) - 1);
 373 }
 374
 375 STATIC void
 376 xfs_bmbt_init_rec_from_cur(
 377         struct xfs_btree_cur    *cur,
 378         union xfs_btree_rec     *rec)
 379 {
 380         xfs_bmbt_disk_set_all(&rec->bmbt, &cur->bc_rec.b);
 381 }
 382
 383 STATIC void
 384 xfs_bmbt_init_ptr_from_cur(
 385         struct xfs_btree_cur    *cur,
 386         union xfs_btree_ptr     *ptr)
 387 {
 388         ptr->l = 0;
 389 }
 390
 391 STATIC int64_t
 392 xfs_bmbt_key_diff(
 393         struct xfs_btree_cur    *cur,
 394         union xfs_btree_key     *key)
 395 {
 396         return (int64_t)be64_to_cpu(key->bmbt.br_startoff) -
 397                                       cur->bc_rec.b.br_startoff;
 398 }
 399
 400 STATIC int64_t
 401 xfs_bmbt_diff_two_keys(
 402         struct xfs_btree_cur    *cur,
 403         union xfs_btree_key     *k1,
 404         union xfs_btree_key     *k2)
 405 {
 406         return (int64_t)be64_to_cpu(k1->bmbt.br_startoff) -
 407                           be64_to_cpu(k2->bmbt.br_startoff);
 408 }
 409
 410 static xfs_failaddr_t
 411 xfs_bmbt_verify(
 412         struct xfs_buf          *bp)
 413 {
 414         struct xfs_mount        *mp = bp->b_target->bt_mount;
 415         struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
 416         xfs_failaddr_t          fa;
 417         unsigned int            level;
 418
 419         switch (block->bb_magic) {
 420         case cpu_to_be32(XFS_BMAP_CRC_MAGIC):
 421                 /*
 422                  * XXX: need a better way of verifying the owner here. Right now
 423                  * just make sure there has been one set.
 424                  */
 425                 fa = xfs_btree_lblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
 426                 if (fa)
 427                         return fa;
 428                 /* fall through */
 429         case cpu_to_be32(XFS_BMAP_MAGIC):
 430                 break;
 431         default:
 432                 return __this_address;
 433         }
 434
 435         /*
 436          * numrecs and level verification.
 437          *
 438          * We don't know what fork we belong to, so just verify that the level
 439          * is less than the maximum of the two. Later checks will be more
 440          * precise.
 441          */
 442         level = be16_to_cpu(block->bb_level);
 443         if (level > max(mp->m_bm_maxlevels[0], mp->m_bm_maxlevels[1]))
 444                 return __this_address;
 445
 446         return xfs_btree_lblock_verify(bp, mp->m_bmap_dmxr[level != 0]);
 447 }
 448
 449 static void
 450 xfs_bmbt_read_verify(
 451         struct xfs_buf  *bp)
 452 {
 453         xfs_failaddr_t  fa;
 454
 455         if (!xfs_btree_lblock_verify_crc(bp))
 456                 xfs_verifier_error(bp, -EFSBADCRC, __this_address);
 457         else {
 458                 fa = xfs_bmbt_verify(bp);
 459                 if (fa)
 460                         xfs_verifier_error(bp, -EFSCORRUPTED, fa);
 461         }
 462
 463         if (bp->b_error)
 464                 trace_xfs_btree_corrupt(bp, _RET_IP_);
 465 }
 466
 467 static void
 468 xfs_bmbt_write_verify(
 469         struct xfs_buf  *bp)
 470 {
 471         xfs_failaddr_t  fa;
 472
 473         fa = xfs_bmbt_verify(bp);
 474         if (fa) {
 475                 trace_xfs_btree_corrupt(bp, _RET_IP_);
 476                 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
 477                 return;
 478         }
 479         xfs_btree_lblock_calc_crc(bp);
 480 }
 481
 482 const struct xfs_buf_ops xfs_bmbt_buf_ops = {
 483         .name = "xfs_bmbt",
 484         .verify_read = xfs_bmbt_read_verify,
 485         .verify_write = xfs_bmbt_write_verify,
 486         .verify_struct = xfs_bmbt_verify,
 487 };
 488
 489
 490 STATIC int
 491 xfs_bmbt_keys_inorder(
 492         struct xfs_btree_cur    *cur,
 493         union xfs_btree_key     *k1,
 494         union xfs_btree_key     *k2)
 495 {
 496         return be64_to_cpu(k1->bmbt.br_startoff) <
 497                 be64_to_cpu(k2->bmbt.br_startoff);
 498 }
 499
 500 STATIC int
 501 xfs_bmbt_recs_inorder(
 502         struct xfs_btree_cur    *cur,
 503         union xfs_btree_rec     *r1,
 504         union xfs_btree_rec     *r2)
 505 {
 506         return xfs_bmbt_disk_get_startoff(&r1->bmbt) +
 507                 xfs_bmbt_disk_get_blockcount(&r1->bmbt) <=
 508                 xfs_bmbt_disk_get_startoff(&r2->bmbt);
 509 }
 510
 511 static const struct xfs_btree_ops xfs_bmbt_ops = {
 512         .rec_len                = sizeof(xfs_bmbt_rec_t),
 513         .key_len                = sizeof(xfs_bmbt_key_t),
 514
 515         .dup_cursor             = xfs_bmbt_dup_cursor,
 516         .update_cursor          = xfs_bmbt_update_cursor,
 517         .alloc_block            = xfs_bmbt_alloc_block,
 518         .free_block             = xfs_bmbt_free_block,
 519         .get_maxrecs            = xfs_bmbt_get_maxrecs,
 520         .get_minrecs            = xfs_bmbt_get_minrecs,
 521         .get_dmaxrecs           = xfs_bmbt_get_dmaxrecs,
 522         .init_key_from_rec      = xfs_bmbt_init_key_from_rec,
 523         .init_high_key_from_rec = xfs_bmbt_init_high_key_from_rec,
 524         .init_rec_from_cur      = xfs_bmbt_init_rec_from_cur,
 525         .init_ptr_from_cur      = xfs_bmbt_init_ptr_from_cur,
 526         .key_diff               = xfs_bmbt_key_diff,
 527         .diff_two_keys          = xfs_bmbt_diff_two_keys,
 528         .buf_ops                = &xfs_bmbt_buf_ops,
 529         .keys_inorder           = xfs_bmbt_keys_inorder,
 530         .recs_inorder           = xfs_bmbt_recs_inorder,
 531 };
 532
 533 /*
 534  * Allocate a new bmap btree cursor.
 535  */
 536 struct xfs_btree_cur *                          /* new bmap btree cursor */
 537 xfs_bmbt_init_cursor(
 538         struct xfs_mount        *mp,            /* file system mount point */
 539         struct xfs_trans        *tp,            /* transaction pointer */
 540         struct xfs_inode        *ip,            /* inode owning the btree */
 541         int                     whichfork)      /* data or attr fork */
 542 {
 543         struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, whichfork);
 544         struct xfs_btree_cur    *cur;
 545         ASSERT(whichfork != XFS_COW_FORK);
 546
 547         cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
 548
 549         cur->bc_tp = tp;
 550         cur->bc_mp = mp;
 551         cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
 552         cur->bc_btnum = XFS_BTNUM_BMAP;
 553         cur->bc_blocklog = mp->m_sb.sb_blocklog;
 554         cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_bmbt_2);
 555
 556         cur->bc_ops = &xfs_bmbt_ops;
 557         cur->bc_flags = XFS_BTREE_LONG_PTRS | XFS_BTREE_ROOT_IN_INODE;
 558         if (xfs_sb_version_hascrc(&mp->m_sb))
 559                 cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
 560
 561         cur->bc_private.b.forksize = XFS_IFORK_SIZE(ip, whichfork);
 562         cur->bc_private.b.ip = ip;
 563         cur->bc_private.b.allocated = 0;
 564         cur->bc_private.b.flags = 0;
 565         cur->bc_private.b.whichfork = whichfork;
 566
 567         return cur;
 568 }
 569
 570 /*
 571  * Calculate number of records in a bmap btree block.
 572  */
 573 int
 574 xfs_bmbt_maxrecs(
 575         struct xfs_mount        *mp,
 576         int                     blocklen,
 577         int                     leaf)
 578 {
 579         blocklen -= XFS_BMBT_BLOCK_LEN(mp);
 580
 581         if (leaf)
 582                 return blocklen / sizeof(xfs_bmbt_rec_t);
 583         return blocklen / (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t));
 584 }
 585
 586 /*
 587  * Calculate number of records in a bmap btree inode root.
 588  */
 589 int
 590 xfs_bmdr_maxrecs(
 591         int                     blocklen,
 592         int                     leaf)
 593 {
 594         blocklen -= sizeof(xfs_bmdr_block_t);
 595
 596         if (leaf)
 597                 return blocklen / sizeof(xfs_bmdr_rec_t);
 598         return blocklen / (sizeof(xfs_bmdr_key_t) + sizeof(xfs_bmdr_ptr_t));
 599 }
 600
 601 /*
 602  * Change the owner of a btree format fork fo the inode passed in. Change it to
 603  * the owner of that is passed in so that we can change owners before or after
 604  * we switch forks between inodes. The operation that the caller is doing will
 605  * determine whether is needs to change owner before or after the switch.
 606  *
 607  * For demand paged transactional modification, the fork switch should be done
 608  * after reading in all the blocks, modifying them and pinning them in the
 609  * transaction. For modification when the buffers are already pinned in memory,
 610  * the fork switch can be done before changing the owner as we won't need to
 611  * validate the owner until the btree buffers are unpinned and writes can occur
 612  * again.
 613  *
 614  * For recovery based ownership change, there is no transactional context and
 615  * so a buffer list must be supplied so that we can record the buffers that we
 616  * modified for the caller to issue IO on.
 617  */
 618 int
 619 xfs_bmbt_change_owner(
 620         struct xfs_trans        *tp,
 621         struct xfs_inode        *ip,
 622         int                     whichfork,
 623         xfs_ino_t               new_owner,
 624         struct list_head        *buffer_list)
 625 {
 626         struct xfs_btree_cur    *cur;
 627         int                     error;
 628
 629         ASSERT(tp || buffer_list);
 630         ASSERT(!(tp && buffer_list));
 631         if (whichfork == XFS_DATA_FORK)
 632                 ASSERT(ip->i_d.di_format == XFS_DINODE_FMT_BTREE);
 633         else
 634                 ASSERT(ip->i_d.di_aformat == XFS_DINODE_FMT_BTREE);
 635
 636         cur = xfs_bmbt_init_cursor(ip->i_mount, tp, ip, whichfork);
 637         if (!cur)
 638                 return -ENOMEM;
 639         cur->bc_private.b.flags |= XFS_BTCUR_BPRV_INVALID_OWNER;
 640
 641         error = xfs_btree_change_owner(cur, new_owner, buffer_list);
 642         xfs_btree_del_cursor(cur, error);
 643         return error;
 644 }
 645
 646 /* Calculate the bmap btree size for some records. */
 647 unsigned long long
 648 xfs_bmbt_calc_size(
 649         struct xfs_mount        *mp,
 650         unsigned long long      len)
 651 {
 652         return xfs_btree_calc_size(mp->m_bmap_dmnr, len);
 653 }