fs/xfs/libxfs/xfs_bmap_btree.c

   1 /*
   2  * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include "xfs.h"
  19 #include "xfs_fs.h"
  20 #include "xfs_shared.h"
  21 #include "xfs_format.h"
  22 #include "xfs_log_format.h"
  23 #include "xfs_trans_resv.h"
  24 #include "xfs_bit.h"
  25 #include "xfs_mount.h"
  26 #include "xfs_defer.h"
  27 #include "xfs_inode.h"
  28 #include "xfs_trans.h"
  29 #include "xfs_inode_item.h"
  30 #include "xfs_alloc.h"
  31 #include "xfs_btree.h"
  32 #include "xfs_bmap_btree.h"
  33 #include "xfs_bmap.h"
  34 #include "xfs_error.h"
  35 #include "xfs_quota.h"
  36 #include "xfs_trace.h"
  37 #include "xfs_cksum.h"
  38 #include "xfs_rmap.h"
  39
  40 /*
  41  * Convert on-disk form of btree root to in-memory form.
  42  */
  43 void
  44 xfs_bmdr_to_bmbt(
  45         struct xfs_inode        *ip,
  46         xfs_bmdr_block_t        *dblock,
  47         int                     dblocklen,
  48         struct xfs_btree_block  *rblock,
  49         int                     rblocklen)
  50 {
  51         struct xfs_mount        *mp = ip->i_mount;
  52         int                     dmxr;
  53         xfs_bmbt_key_t          *fkp;
  54         __be64                  *fpp;
  55         xfs_bmbt_key_t          *tkp;
  56         __be64                  *tpp;
  57
  58         xfs_btree_init_block_int(mp, rblock, XFS_BUF_DADDR_NULL,
  59                                  XFS_BTNUM_BMAP, 0, 0, ip->i_ino,
  60                                  XFS_BTREE_LONG_PTRS);
  61         rblock->bb_level = dblock->bb_level;
  62         ASSERT(be16_to_cpu(rblock->bb_level) > 0);
  63         rblock->bb_numrecs = dblock->bb_numrecs;
  64         dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
  65         fkp = XFS_BMDR_KEY_ADDR(dblock, 1);
  66         tkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
  67         fpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
  68         tpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
  69         dmxr = be16_to_cpu(dblock->bb_numrecs);
  70         memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
  71         memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
  72 }
  73
  74 void
  75 xfs_bmbt_disk_get_all(
  76         struct xfs_bmbt_rec     *rec,
  77         struct xfs_bmbt_irec    *irec)
  78 {
  79         uint64_t                l0 = get_unaligned_be64(&rec->l0);
  80         uint64_t                l1 = get_unaligned_be64(&rec->l1);
  81
  82         irec->br_startoff = (l0 & xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
  83         irec->br_startblock = ((l0 & xfs_mask64lo(9)) << 43) | (l1 >> 21);
  84         irec->br_blockcount = l1 & xfs_mask64lo(21);
  85         if (l0 >> (64 - BMBT_EXNTFLAG_BITLEN))
  86                 irec->br_state = XFS_EXT_UNWRITTEN;
  87         else
  88                 irec->br_state = XFS_EXT_NORM;
  89 }
  90
  91 /*
  92  * Extract the blockcount field from an on disk bmap extent record.
  93  */
  94 xfs_filblks_t
  95 xfs_bmbt_disk_get_blockcount(
  96         xfs_bmbt_rec_t  *r)
  97 {
  98         return (xfs_filblks_t)(be64_to_cpu(r->l1) & xfs_mask64lo(21));
  99 }
 100
 101 /*
 102  * Extract the startoff field from a disk format bmap extent record.
 103  */
 104 xfs_fileoff_t
 105 xfs_bmbt_disk_get_startoff(
 106         xfs_bmbt_rec_t  *r)
 107 {
 108         return ((xfs_fileoff_t)be64_to_cpu(r->l0) &
 109                  xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
 110 }
 111
 112 /*
 113  * Set all the fields in a bmap extent record from the uncompressed form.
 114  */
 115 void
 116 xfs_bmbt_disk_set_all(
 117         struct xfs_bmbt_rec     *r,
 118         struct xfs_bmbt_irec    *s)
 119 {
 120         int                     extent_flag = (s->br_state != XFS_EXT_NORM);
 121
 122         ASSERT(s->br_state == XFS_EXT_NORM || s->br_state == XFS_EXT_UNWRITTEN);
 123         ASSERT(!(s->br_startoff & xfs_mask64hi(64-BMBT_STARTOFF_BITLEN)));
 124         ASSERT(!(s->br_blockcount & xfs_mask64hi(64-BMBT_BLOCKCOUNT_BITLEN)));
 125         ASSERT(!(s->br_startblock & xfs_mask64hi(64-BMBT_STARTBLOCK_BITLEN)));
 126
 127         put_unaligned_be64(
 128                 ((xfs_bmbt_rec_base_t)extent_flag << 63) |
 129                  ((xfs_bmbt_rec_base_t)s->br_startoff << 9) |
 130                  ((xfs_bmbt_rec_base_t)s->br_startblock >> 43), &r->l0);
 131         put_unaligned_be64(
 132                 ((xfs_bmbt_rec_base_t)s->br_startblock << 21) |
 133                  ((xfs_bmbt_rec_base_t)s->br_blockcount &
 134                   (xfs_bmbt_rec_base_t)xfs_mask64lo(21)), &r->l1);
 135 }
 136
 137 /*
 138  * Convert in-memory form of btree root to on-disk form.
 139  */
 140 void
 141 xfs_bmbt_to_bmdr(
 142         struct xfs_mount        *mp,
 143         struct xfs_btree_block  *rblock,
 144         int                     rblocklen,
 145         xfs_bmdr_block_t        *dblock,
 146         int                     dblocklen)
 147 {
 148         int                     dmxr;
 149         xfs_bmbt_key_t          *fkp;
 150         __be64                  *fpp;
 151         xfs_bmbt_key_t          *tkp;
 152         __be64                  *tpp;
 153
 154         if (xfs_sb_version_hascrc(&mp->m_sb)) {
 155                 ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_CRC_MAGIC));
 156                 ASSERT(uuid_equal(&rblock->bb_u.l.bb_uuid,
 157                        &mp->m_sb.sb_meta_uuid));
 158                 ASSERT(rblock->bb_u.l.bb_blkno ==
 159                        cpu_to_be64(XFS_BUF_DADDR_NULL));
 160         } else
 161                 ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_MAGIC));
 162         ASSERT(rblock->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK));
 163         ASSERT(rblock->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK));
 164         ASSERT(rblock->bb_level != 0);
 165         dblock->bb_level = rblock->bb_level;
 166         dblock->bb_numrecs = rblock->bb_numrecs;
 167         dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
 168         fkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
 169         tkp = XFS_BMDR_KEY_ADDR(dblock, 1);
 170         fpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
 171         tpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
 172         dmxr = be16_to_cpu(dblock->bb_numrecs);
 173         memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
 174         memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
 175 }
 176
 177 STATIC struct xfs_btree_cur *
 178 xfs_bmbt_dup_cursor(
 179         struct xfs_btree_cur    *cur)
 180 {
 181         struct xfs_btree_cur    *new;
 182
 183         new = xfs_bmbt_init_cursor(cur->bc_mp, cur->bc_tp,
 184                         cur->bc_private.b.ip, cur->bc_private.b.whichfork);
 185
 186         /*
 187          * Copy the firstblock, dfops, and flags values,
 188          * since init cursor doesn't get them.
 189          */
 190         new->bc_private.b.firstblock = cur->bc_private.b.firstblock;
 191         new->bc_private.b.dfops = cur->bc_private.b.dfops;
 192         new->bc_private.b.flags = cur->bc_private.b.flags;
 193
 194         return new;
 195 }
 196
 197 STATIC void
 198 xfs_bmbt_update_cursor(
 199         struct xfs_btree_cur    *src,
 200         struct xfs_btree_cur    *dst)
 201 {
 202         ASSERT((dst->bc_private.b.firstblock != NULLFSBLOCK) ||
 203                (dst->bc_private.b.ip->i_d.di_flags & XFS_DIFLAG_REALTIME));
 204         ASSERT(dst->bc_private.b.dfops == src->bc_private.b.dfops);
 205
 206         dst->bc_private.b.allocated += src->bc_private.b.allocated;
 207         dst->bc_private.b.firstblock = src->bc_private.b.firstblock;
 208
 209         src->bc_private.b.allocated = 0;
 210 }
 211
 212 STATIC int
 213 xfs_bmbt_alloc_block(
 214         struct xfs_btree_cur    *cur,
 215         union xfs_btree_ptr     *start,
 216         union xfs_btree_ptr     *new,
 217         int                     *stat)
 218 {
 219         xfs_alloc_arg_t         args;           /* block allocation args */
 220         int                     error;          /* error return value */
 221
 222         memset(&args, 0, sizeof(args));
 223         args.tp = cur->bc_tp;
 224         args.mp = cur->bc_mp;
 225         args.fsbno = cur->bc_private.b.firstblock;
 226         args.firstblock = args.fsbno;
 227         xfs_rmap_ino_bmbt_owner(&args.oinfo, cur->bc_private.b.ip->i_ino,
 228                         cur->bc_private.b.whichfork);
 229
 230         if (args.fsbno == NULLFSBLOCK) {
 231                 args.fsbno = be64_to_cpu(start->l);
 232                 args.type = XFS_ALLOCTYPE_START_BNO;
 233                 /*
 234                  * Make sure there is sufficient room left in the AG to
 235                  * complete a full tree split for an extent insert.  If
 236                  * we are converting the middle part of an extent then
 237                  * we may need space for two tree splits.
 238                  *
 239                  * We are relying on the caller to make the correct block
 240                  * reservation for this operation to succeed.  If the
 241                  * reservation amount is insufficient then we may fail a
 242                  * block allocation here and corrupt the filesystem.
 243                  */
 244                 args.minleft = args.tp->t_blk_res;
 245         } else if (cur->bc_private.b.dfops->dop_low) {
 246                 args.type = XFS_ALLOCTYPE_START_BNO;
 247         } else {
 248                 args.type = XFS_ALLOCTYPE_NEAR_BNO;
 249         }
 250
 251         args.minlen = args.maxlen = args.prod = 1;
 252         args.wasdel = cur->bc_private.b.flags & XFS_BTCUR_BPRV_WASDEL;
 253         if (!args.wasdel && args.tp->t_blk_res == 0) {
 254                 error = -ENOSPC;
 255                 goto error0;
 256         }
 257         error = xfs_alloc_vextent(&args);
 258         if (error)
 259                 goto error0;
 260
 261         if (args.fsbno == NULLFSBLOCK && args.minleft) {
 262                 /*
 263                  * Could not find an AG with enough free space to satisfy
 264                  * a full btree split.  Try again and if
 265                  * successful activate the lowspace algorithm.
 266                  */
 267                 args.fsbno = 0;
 268                 args.type = XFS_ALLOCTYPE_FIRST_AG;
 269                 error = xfs_alloc_vextent(&args);
 270                 if (error)
 271                         goto error0;
 272                 cur->bc_private.b.dfops->dop_low = true;
 273         }
 274         if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
 275                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
 276                 *stat = 0;
 277                 return 0;
 278         }
 279         ASSERT(args.len == 1);
 280         cur->bc_private.b.firstblock = args.fsbno;
 281         cur->bc_private.b.allocated++;
 282         cur->bc_private.b.ip->i_d.di_nblocks++;
 283         xfs_trans_log_inode(args.tp, cur->bc_private.b.ip, XFS_ILOG_CORE);
 284         xfs_trans_mod_dquot_byino(args.tp, cur->bc_private.b.ip,
 285                         XFS_TRANS_DQ_BCOUNT, 1L);
 286
 287         new->l = cpu_to_be64(args.fsbno);
 288
 289         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
 290         *stat = 1;
 291         return 0;
 292
 293  error0:
 294         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
 295         return error;
 296 }
 297
 298 STATIC int
 299 xfs_bmbt_free_block(
 300         struct xfs_btree_cur    *cur,
 301         struct xfs_buf          *bp)
 302 {
 303         struct xfs_mount        *mp = cur->bc_mp;
 304         struct xfs_inode        *ip = cur->bc_private.b.ip;
 305         struct xfs_trans        *tp = cur->bc_tp;
 306         xfs_fsblock_t           fsbno = XFS_DADDR_TO_FSB(mp, XFS_BUF_ADDR(bp));
 307         struct xfs_owner_info   oinfo;
 308
 309         xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, cur->bc_private.b.whichfork);
 310         xfs_bmap_add_free(mp, cur->bc_private.b.dfops, fsbno, 1, &oinfo);
 311         ip->i_d.di_nblocks--;
 312
 313         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 314         xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
 315         return 0;
 316 }
 317
 318 STATIC int
 319 xfs_bmbt_get_minrecs(
 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) / 2;
 331         }
 332
 333         return cur->bc_mp->m_bmap_dmnr[level != 0];
 334 }
 335
 336 int
 337 xfs_bmbt_get_maxrecs(
 338         struct xfs_btree_cur    *cur,
 339         int                     level)
 340 {
 341         if (level == cur->bc_nlevels - 1) {
 342                 struct xfs_ifork        *ifp;
 343
 344                 ifp = XFS_IFORK_PTR(cur->bc_private.b.ip,
 345                                     cur->bc_private.b.whichfork);
 346
 347                 return xfs_bmbt_maxrecs(cur->bc_mp,
 348                                         ifp->if_broot_bytes, level == 0);
 349         }
 350
 351         return cur->bc_mp->m_bmap_dmxr[level != 0];
 352
 353 }
 354
 355 /*
 356  * Get the maximum records we could store in the on-disk format.
 357  *
 358  * For non-root nodes this is equivalent to xfs_bmbt_get_maxrecs, but
 359  * for the root node this checks the available space in the dinode fork
 360  * so that we can resize the in-memory buffer to match it.  After a
 361  * resize to the maximum size this function returns the same value
 362  * as xfs_bmbt_get_maxrecs for the root node, too.
 363  */
 364 STATIC int
 365 xfs_bmbt_get_dmaxrecs(
 366         struct xfs_btree_cur    *cur,
 367         int                     level)
 368 {
 369         if (level != cur->bc_nlevels - 1)
 370                 return cur->bc_mp->m_bmap_dmxr[level != 0];
 371         return xfs_bmdr_maxrecs(cur->bc_private.b.forksize, level == 0);
 372 }
 373
 374 STATIC void
 375 xfs_bmbt_init_key_from_rec(
 376         union xfs_btree_key     *key,
 377         union xfs_btree_rec     *rec)
 378 {
 379         key->bmbt.br_startoff =
 380                 cpu_to_be64(xfs_bmbt_disk_get_startoff(&rec->bmbt));
 381 }
 382
 383 STATIC void
 384 xfs_bmbt_init_high_key_from_rec(
 385         union xfs_btree_key     *key,
 386         union xfs_btree_rec     *rec)
 387 {
 388         key->bmbt.br_startoff = cpu_to_be64(
 389                         xfs_bmbt_disk_get_startoff(&rec->bmbt) +
 390                         xfs_bmbt_disk_get_blockcount(&rec->bmbt) - 1);
 391 }
 392
 393 STATIC void
 394 xfs_bmbt_init_rec_from_cur(
 395         struct xfs_btree_cur    *cur,
 396         union xfs_btree_rec     *rec)
 397 {
 398         xfs_bmbt_disk_set_all(&rec->bmbt, &cur->bc_rec.b);
 399 }
 400
 401 STATIC void
 402 xfs_bmbt_init_ptr_from_cur(
 403         struct xfs_btree_cur    *cur,
 404         union xfs_btree_ptr     *ptr)
 405 {
 406         ptr->l = 0;
 407 }
 408
 409 STATIC int64_t
 410 xfs_bmbt_key_diff(
 411         struct xfs_btree_cur    *cur,
 412         union xfs_btree_key     *key)
 413 {
 414         return (int64_t)be64_to_cpu(key->bmbt.br_startoff) -
 415                                       cur->bc_rec.b.br_startoff;
 416 }
 417
 418 STATIC int64_t
 419 xfs_bmbt_diff_two_keys(
 420         struct xfs_btree_cur    *cur,
 421         union xfs_btree_key     *k1,
 422         union xfs_btree_key     *k2)
 423 {
 424         return (int64_t)be64_to_cpu(k1->bmbt.br_startoff) -
 425                           be64_to_cpu(k2->bmbt.br_startoff);
 426 }
 427
 428 static xfs_failaddr_t
 429 xfs_bmbt_verify(
 430         struct xfs_buf          *bp)
 431 {
 432         struct xfs_mount        *mp = bp->b_target->bt_mount;
 433         struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
 434         xfs_failaddr_t          fa;
 435         unsigned int            level;
 436
 437         switch (block->bb_magic) {
 438         case cpu_to_be32(XFS_BMAP_CRC_MAGIC):
 439                 /*
 440                  * XXX: need a better way of verifying the owner here. Right now
 441                  * just make sure there has been one set.
 442                  */
 443                 fa = xfs_btree_lblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
 444                 if (fa)
 445                         return fa;
 446                 /* fall through */
 447         case cpu_to_be32(XFS_BMAP_MAGIC):
 448                 break;
 449         default:
 450                 return __this_address;
 451         }
 452
 453         /*
 454          * numrecs and level verification.
 455          *
 456          * We don't know what fork we belong to, so just verify that the level
 457          * is less than the maximum of the two. Later checks will be more
 458          * precise.
 459          */
 460         level = be16_to_cpu(block->bb_level);
 461         if (level > max(mp->m_bm_maxlevels[0], mp->m_bm_maxlevels[1]))
 462                 return __this_address;
 463
 464         return xfs_btree_lblock_verify(bp, mp->m_bmap_dmxr[level != 0]);
 465 }
 466
 467 static void
 468 xfs_bmbt_read_verify(
 469         struct xfs_buf  *bp)
 470 {
 471         xfs_failaddr_t  fa;
 472
 473         if (!xfs_btree_lblock_verify_crc(bp))
 474                 xfs_verifier_error(bp, -EFSBADCRC, __this_address);
 475         else {
 476                 fa = xfs_bmbt_verify(bp);
 477                 if (fa)
 478                         xfs_verifier_error(bp, -EFSCORRUPTED, fa);
 479         }
 480
 481         if (bp->b_error)
 482                 trace_xfs_btree_corrupt(bp, _RET_IP_);
 483 }
 484
 485 static void
 486 xfs_bmbt_write_verify(
 487         struct xfs_buf  *bp)
 488 {
 489         xfs_failaddr_t  fa;
 490
 491         fa = xfs_bmbt_verify(bp);
 492         if (fa) {
 493                 trace_xfs_btree_corrupt(bp, _RET_IP_);
 494                 xfs_verifier_error(bp, -EFSCORRUPTED, fa);
 495                 return;
 496         }
 497         xfs_btree_lblock_calc_crc(bp);
 498 }
 499
 500 const struct xfs_buf_ops xfs_bmbt_buf_ops = {
 501         .name = "xfs_bmbt",
 502         .verify_read = xfs_bmbt_read_verify,
 503         .verify_write = xfs_bmbt_write_verify,
 504         .verify_struct = xfs_bmbt_verify,
 505 };
 506
 507
 508 STATIC int
 509 xfs_bmbt_keys_inorder(
 510         struct xfs_btree_cur    *cur,
 511         union xfs_btree_key     *k1,
 512         union xfs_btree_key     *k2)
 513 {
 514         return be64_to_cpu(k1->bmbt.br_startoff) <
 515                 be64_to_cpu(k2->bmbt.br_startoff);
 516 }
 517
 518 STATIC int
 519 xfs_bmbt_recs_inorder(
 520         struct xfs_btree_cur    *cur,
 521         union xfs_btree_rec     *r1,
 522         union xfs_btree_rec     *r2)
 523 {
 524         return xfs_bmbt_disk_get_startoff(&r1->bmbt) +
 525                 xfs_bmbt_disk_get_blockcount(&r1->bmbt) <=
 526                 xfs_bmbt_disk_get_startoff(&r2->bmbt);
 527 }
 528
 529 static const struct xfs_btree_ops xfs_bmbt_ops = {
 530         .rec_len                = sizeof(xfs_bmbt_rec_t),
 531         .key_len                = sizeof(xfs_bmbt_key_t),
 532
 533         .dup_cursor             = xfs_bmbt_dup_cursor,
 534         .update_cursor          = xfs_bmbt_update_cursor,
 535         .alloc_block            = xfs_bmbt_alloc_block,
 536         .free_block             = xfs_bmbt_free_block,
 537         .get_maxrecs            = xfs_bmbt_get_maxrecs,
 538         .get_minrecs            = xfs_bmbt_get_minrecs,
 539         .get_dmaxrecs           = xfs_bmbt_get_dmaxrecs,
 540         .init_key_from_rec      = xfs_bmbt_init_key_from_rec,
 541         .init_high_key_from_rec = xfs_bmbt_init_high_key_from_rec,
 542         .init_rec_from_cur      = xfs_bmbt_init_rec_from_cur,
 543         .init_ptr_from_cur      = xfs_bmbt_init_ptr_from_cur,
 544         .key_diff               = xfs_bmbt_key_diff,
 545         .diff_two_keys          = xfs_bmbt_diff_two_keys,
 546         .buf_ops                = &xfs_bmbt_buf_ops,
 547         .keys_inorder           = xfs_bmbt_keys_inorder,
 548         .recs_inorder           = xfs_bmbt_recs_inorder,
 549 };
 550
 551 /*
 552  * Allocate a new bmap btree cursor.
 553  */
 554 struct xfs_btree_cur *                          /* new bmap btree cursor */
 555 xfs_bmbt_init_cursor(
 556         struct xfs_mount        *mp,            /* file system mount point */
 557         struct xfs_trans        *tp,            /* transaction pointer */
 558         struct xfs_inode        *ip,            /* inode owning the btree */
 559         int                     whichfork)      /* data or attr fork */
 560 {
 561         struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, whichfork);
 562         struct xfs_btree_cur    *cur;
 563         ASSERT(whichfork != XFS_COW_FORK);
 564
 565         cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
 566
 567         cur->bc_tp = tp;
 568         cur->bc_mp = mp;
 569         cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
 570         cur->bc_btnum = XFS_BTNUM_BMAP;
 571         cur->bc_blocklog = mp->m_sb.sb_blocklog;
 572         cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_bmbt_2);
 573
 574         cur->bc_ops = &xfs_bmbt_ops;
 575         cur->bc_flags = XFS_BTREE_LONG_PTRS | XFS_BTREE_ROOT_IN_INODE;
 576         if (xfs_sb_version_hascrc(&mp->m_sb))
 577                 cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
 578
 579         cur->bc_private.b.forksize = XFS_IFORK_SIZE(ip, whichfork);
 580         cur->bc_private.b.ip = ip;
 581         cur->bc_private.b.firstblock = NULLFSBLOCK;
 582         cur->bc_private.b.dfops = NULL;
 583         cur->bc_private.b.allocated = 0;
 584         cur->bc_private.b.flags = 0;
 585         cur->bc_private.b.whichfork = whichfork;
 586
 587         return cur;
 588 }
 589
 590 /*
 591  * Calculate number of records in a bmap btree block.
 592  */
 593 int
 594 xfs_bmbt_maxrecs(
 595         struct xfs_mount        *mp,
 596         int                     blocklen,
 597         int                     leaf)
 598 {
 599         blocklen -= XFS_BMBT_BLOCK_LEN(mp);
 600
 601         if (leaf)
 602                 return blocklen / sizeof(xfs_bmbt_rec_t);
 603         return blocklen / (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t));
 604 }
 605
 606 /*
 607  * Calculate number of records in a bmap btree inode root.
 608  */
 609 int
 610 xfs_bmdr_maxrecs(
 611         int                     blocklen,
 612         int                     leaf)
 613 {
 614         blocklen -= sizeof(xfs_bmdr_block_t);
 615
 616         if (leaf)
 617                 return blocklen / sizeof(xfs_bmdr_rec_t);
 618         return blocklen / (sizeof(xfs_bmdr_key_t) + sizeof(xfs_bmdr_ptr_t));
 619 }
 620
 621 /*
 622  * Change the owner of a btree format fork fo the inode passed in. Change it to
 623  * the owner of that is passed in so that we can change owners before or after
 624  * we switch forks between inodes. The operation that the caller is doing will
 625  * determine whether is needs to change owner before or after the switch.
 626  *
 627  * For demand paged transactional modification, the fork switch should be done
 628  * after reading in all the blocks, modifying them and pinning them in the
 629  * transaction. For modification when the buffers are already pinned in memory,
 630  * the fork switch can be done before changing the owner as we won't need to
 631  * validate the owner until the btree buffers are unpinned and writes can occur
 632  * again.
 633  *
 634  * For recovery based ownership change, there is no transactional context and
 635  * so a buffer list must be supplied so that we can record the buffers that we
 636  * modified for the caller to issue IO on.
 637  */
 638 int
 639 xfs_bmbt_change_owner(
 640         struct xfs_trans        *tp,
 641         struct xfs_inode        *ip,
 642         int                     whichfork,
 643         xfs_ino_t               new_owner,
 644         struct list_head        *buffer_list)
 645 {
 646         struct xfs_btree_cur    *cur;
 647         int                     error;
 648
 649         ASSERT(tp || buffer_list);
 650         ASSERT(!(tp && buffer_list));
 651         if (whichfork == XFS_DATA_FORK)
 652                 ASSERT(ip->i_d.di_format == XFS_DINODE_FMT_BTREE);
 653         else
 654                 ASSERT(ip->i_d.di_aformat == XFS_DINODE_FMT_BTREE);
 655
 656         cur = xfs_bmbt_init_cursor(ip->i_mount, tp, ip, whichfork);
 657         if (!cur)
 658                 return -ENOMEM;
 659         cur->bc_private.b.flags |= XFS_BTCUR_BPRV_INVALID_OWNER;
 660
 661         error = xfs_btree_change_owner(cur, new_owner, buffer_list);
 662         xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
 663         return error;
 664 }