git.oblomov.eu Git - linux-2.6/blob - fs/xfs/xfs_btree.c

   1 /*
   2  * Copyright (c) 2000-2002,2005 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_types.h"
  21 #include "xfs_bit.h"
  22 #include "xfs_log.h"
  23 #include "xfs_inum.h"
  24 #include "xfs_trans.h"
  25 #include "xfs_sb.h"
  26 #include "xfs_ag.h"
  27 #include "xfs_dir2.h"
  28 #include "xfs_dmapi.h"
  29 #include "xfs_mount.h"
  30 #include "xfs_bmap_btree.h"
  31 #include "xfs_alloc_btree.h"
  32 #include "xfs_ialloc_btree.h"
  33 #include "xfs_dir2_sf.h"
  34 #include "xfs_attr_sf.h"
  35 #include "xfs_dinode.h"
  36 #include "xfs_inode.h"
  37 #include "xfs_btree.h"
  38 #include "xfs_ialloc.h"
  39 #include "xfs_error.h"
  40
  41 /*
  42  * Cursor allocation zone.
  43  */
  44 kmem_zone_t     *xfs_btree_cur_zone;
  45
  46 /*
  47  * Btree magic numbers.
  48  */
  49 const __uint32_t xfs_magics[XFS_BTNUM_MAX] =
  50 {
  51         XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, XFS_BMAP_MAGIC, XFS_IBT_MAGIC
  52 };
  53
  54 /*
  55  * Prototypes for internal routines.
  56  */
  57
  58 /*
  59  * Checking routine: return maxrecs for the block.
  60  */
  61 STATIC int                              /* number of records fitting in block */
  62 xfs_btree_maxrecs(
  63         xfs_btree_cur_t         *cur,   /* btree cursor */
  64         xfs_btree_block_t       *block);/* generic btree block pointer */
  65
  66 /*
  67  * Internal routines.
  68  */
  69
  70 /*
  71  * Retrieve the block pointer from the cursor at the given level.
  72  * This may be a bmap btree root or from a buffer.
  73  */
  74 STATIC xfs_btree_block_t *                      /* generic btree block pointer */
  75 xfs_btree_get_block(
  76         xfs_btree_cur_t         *cur,   /* btree cursor */
  77         int                     level,  /* level in btree */
  78         struct xfs_buf          **bpp); /* buffer containing the block */
  79
  80 /*
  81  * Checking routine: return maxrecs for the block.
  82  */
  83 STATIC int                              /* number of records fitting in block */
  84 xfs_btree_maxrecs(
  85         xfs_btree_cur_t         *cur,   /* btree cursor */
  86         xfs_btree_block_t       *block) /* generic btree block pointer */
  87 {
  88         switch (cur->bc_btnum) {
  89         case XFS_BTNUM_BNO:
  90         case XFS_BTNUM_CNT:
  91                 return (int)XFS_ALLOC_BLOCK_MAXRECS(
  92                                 be16_to_cpu(block->bb_h.bb_level), cur);
  93         case XFS_BTNUM_BMAP:
  94                 return (int)XFS_BMAP_BLOCK_IMAXRECS(
  95                                 be16_to_cpu(block->bb_h.bb_level), cur);
  96         case XFS_BTNUM_INO:
  97                 return (int)XFS_INOBT_BLOCK_MAXRECS(
  98                                 be16_to_cpu(block->bb_h.bb_level), cur);
  99         default:
 100                 ASSERT(0);
 101                 return 0;
 102         }
 103 }
 104
 105 /*
 106  * External routines.
 107  */
 108
 109 #ifdef DEBUG
 110 /*
 111  * Debug routine: check that block header is ok.
 112  */
 113 void
 114 xfs_btree_check_block(
 115         xfs_btree_cur_t         *cur,   /* btree cursor */
 116         xfs_btree_block_t       *block, /* generic btree block pointer */
 117         int                     level,  /* level of the btree block */
 118         xfs_buf_t               *bp)    /* buffer containing block, if any */
 119 {
 120         if (XFS_BTREE_LONG_PTRS(cur->bc_btnum))
 121                 xfs_btree_check_lblock(cur, (xfs_btree_lblock_t *)block, level,
 122                         bp);
 123         else
 124                 xfs_btree_check_sblock(cur, (xfs_btree_sblock_t *)block, level,
 125                         bp);
 126 }
 127
 128 /*
 129  * Debug routine: check that keys are in the right order.
 130  */
 131 void
 132 xfs_btree_check_key(
 133         xfs_btnum_t     btnum,          /* btree identifier */
 134         void            *ak1,           /* pointer to left (lower) key */
 135         void            *ak2)           /* pointer to right (higher) key */
 136 {
 137         switch (btnum) {
 138         case XFS_BTNUM_BNO: {
 139                 xfs_alloc_key_t *k1;
 140                 xfs_alloc_key_t *k2;
 141
 142                 k1 = ak1;
 143                 k2 = ak2;
 144                 ASSERT(be32_to_cpu(k1->ar_startblock) < be32_to_cpu(k2->ar_startblock));
 145                 break;
 146             }
 147         case XFS_BTNUM_CNT: {
 148                 xfs_alloc_key_t *k1;
 149                 xfs_alloc_key_t *k2;
 150
 151                 k1 = ak1;
 152                 k2 = ak2;
 153                 ASSERT(be32_to_cpu(k1->ar_blockcount) < be32_to_cpu(k2->ar_blockcount) ||
 154                        (k1->ar_blockcount == k2->ar_blockcount &&
 155                         be32_to_cpu(k1->ar_startblock) < be32_to_cpu(k2->ar_startblock)));
 156                 break;
 157             }
 158         case XFS_BTNUM_BMAP: {
 159                 xfs_bmbt_key_t  *k1;
 160                 xfs_bmbt_key_t  *k2;
 161
 162                 k1 = ak1;
 163                 k2 = ak2;
 164                 ASSERT(be64_to_cpu(k1->br_startoff) < be64_to_cpu(k2->br_startoff));
 165                 break;
 166             }
 167         case XFS_BTNUM_INO: {
 168                 xfs_inobt_key_t *k1;
 169                 xfs_inobt_key_t *k2;
 170
 171                 k1 = ak1;
 172                 k2 = ak2;
 173                 ASSERT(be32_to_cpu(k1->ir_startino) < be32_to_cpu(k2->ir_startino));
 174                 break;
 175             }
 176         default:
 177                 ASSERT(0);
 178         }
 179 }
 180 #endif  /* DEBUG */
 181
 182 /*
 183  * Checking routine: check that long form block header is ok.
 184  */
 185 /* ARGSUSED */
 186 int                                     /* error (0 or EFSCORRUPTED) */
 187 xfs_btree_check_lblock(
 188         xfs_btree_cur_t         *cur,   /* btree cursor */
 189         xfs_btree_lblock_t      *block, /* btree long form block pointer */
 190         int                     level,  /* level of the btree block */
 191         xfs_buf_t               *bp)    /* buffer for block, if any */
 192 {
 193         int                     lblock_ok; /* block passes checks */
 194         xfs_mount_t             *mp;    /* file system mount point */
 195
 196         mp = cur->bc_mp;
 197         lblock_ok =
 198                 be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
 199                 be16_to_cpu(block->bb_level) == level &&
 200                 be16_to_cpu(block->bb_numrecs) <=
 201                         xfs_btree_maxrecs(cur, (xfs_btree_block_t *)block) &&
 202                 block->bb_leftsib &&
 203                 (be64_to_cpu(block->bb_leftsib) == NULLDFSBNO ||
 204                  XFS_FSB_SANITY_CHECK(mp, be64_to_cpu(block->bb_leftsib))) &&
 205                 block->bb_rightsib &&
 206                 (be64_to_cpu(block->bb_rightsib) == NULLDFSBNO ||
 207                  XFS_FSB_SANITY_CHECK(mp, be64_to_cpu(block->bb_rightsib)));
 208         if (unlikely(XFS_TEST_ERROR(!lblock_ok, mp, XFS_ERRTAG_BTREE_CHECK_LBLOCK,
 209                         XFS_RANDOM_BTREE_CHECK_LBLOCK))) {
 210                 if (bp)
 211                         xfs_buftrace("LBTREE ERROR", bp);
 212                 XFS_ERROR_REPORT("xfs_btree_check_lblock", XFS_ERRLEVEL_LOW,
 213                                  mp);
 214                 return XFS_ERROR(EFSCORRUPTED);
 215         }
 216         return 0;
 217 }
 218
 219 /*
 220  * Checking routine: check that (long) pointer is ok.
 221  */
 222 int                                     /* error (0 or EFSCORRUPTED) */
 223 xfs_btree_check_lptr(
 224         xfs_btree_cur_t *cur,           /* btree cursor */
 225         xfs_dfsbno_t    ptr,            /* btree block disk address */
 226         int             level)          /* btree block level */
 227 {
 228         xfs_mount_t     *mp;            /* file system mount point */
 229
 230         mp = cur->bc_mp;
 231         XFS_WANT_CORRUPTED_RETURN(
 232                 level > 0 &&
 233                 ptr != NULLDFSBNO &&
 234                 XFS_FSB_SANITY_CHECK(mp, ptr));
 235         return 0;
 236 }
 237
 238 #ifdef DEBUG
 239 /*
 240  * Debug routine: check that records are in the right order.
 241  */
 242 void
 243 xfs_btree_check_rec(
 244         xfs_btnum_t     btnum,          /* btree identifier */
 245         void            *ar1,           /* pointer to left (lower) record */
 246         void            *ar2)           /* pointer to right (higher) record */
 247 {
 248         switch (btnum) {
 249         case XFS_BTNUM_BNO: {
 250                 xfs_alloc_rec_t *r1;
 251                 xfs_alloc_rec_t *r2;
 252
 253                 r1 = ar1;
 254                 r2 = ar2;
 255                 ASSERT(be32_to_cpu(r1->ar_startblock) +
 256                        be32_to_cpu(r1->ar_blockcount) <=
 257                        be32_to_cpu(r2->ar_startblock));
 258                 break;
 259             }
 260         case XFS_BTNUM_CNT: {
 261                 xfs_alloc_rec_t *r1;
 262                 xfs_alloc_rec_t *r2;
 263
 264                 r1 = ar1;
 265                 r2 = ar2;
 266                 ASSERT(be32_to_cpu(r1->ar_blockcount) < be32_to_cpu(r2->ar_blockcount) ||
 267                        (r1->ar_blockcount == r2->ar_blockcount &&
 268                         be32_to_cpu(r1->ar_startblock) < be32_to_cpu(r2->ar_startblock)));
 269                 break;
 270             }
 271         case XFS_BTNUM_BMAP: {
 272                 xfs_bmbt_rec_t  *r1;
 273                 xfs_bmbt_rec_t  *r2;
 274
 275                 r1 = ar1;
 276                 r2 = ar2;
 277                 ASSERT(xfs_bmbt_disk_get_startoff(r1) +
 278                        xfs_bmbt_disk_get_blockcount(r1) <=
 279                        xfs_bmbt_disk_get_startoff(r2));
 280                 break;
 281             }
 282         case XFS_BTNUM_INO: {
 283                 xfs_inobt_rec_t *r1;
 284                 xfs_inobt_rec_t *r2;
 285
 286                 r1 = ar1;
 287                 r2 = ar2;
 288                 ASSERT(be32_to_cpu(r1->ir_startino) + XFS_INODES_PER_CHUNK <=
 289                        be32_to_cpu(r2->ir_startino));
 290                 break;
 291             }
 292         default:
 293                 ASSERT(0);
 294         }
 295 }
 296 #endif  /* DEBUG */
 297
 298 /*
 299  * Checking routine: check that block header is ok.
 300  */
 301 /* ARGSUSED */
 302 int                                     /* error (0 or EFSCORRUPTED) */
 303 xfs_btree_check_sblock(
 304         xfs_btree_cur_t         *cur,   /* btree cursor */
 305         xfs_btree_sblock_t      *block, /* btree short form block pointer */
 306         int                     level,  /* level of the btree block */
 307         xfs_buf_t               *bp)    /* buffer containing block */
 308 {
 309         xfs_buf_t               *agbp;  /* buffer for ag. freespace struct */
 310         xfs_agf_t               *agf;   /* ag. freespace structure */
 311         xfs_agblock_t           agflen; /* native ag. freespace length */
 312         int                     sblock_ok; /* block passes checks */
 313
 314         agbp = cur->bc_private.a.agbp;
 315         agf = XFS_BUF_TO_AGF(agbp);
 316         agflen = be32_to_cpu(agf->agf_length);
 317         sblock_ok =
 318                 be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
 319                 be16_to_cpu(block->bb_level) == level &&
 320                 be16_to_cpu(block->bb_numrecs) <=
 321                         xfs_btree_maxrecs(cur, (xfs_btree_block_t *)block) &&
 322                 (be32_to_cpu(block->bb_leftsib) == NULLAGBLOCK ||
 323                  be32_to_cpu(block->bb_leftsib) < agflen) &&
 324                 block->bb_leftsib &&
 325                 (be32_to_cpu(block->bb_rightsib) == NULLAGBLOCK ||
 326                  be32_to_cpu(block->bb_rightsib) < agflen) &&
 327                 block->bb_rightsib;
 328         if (unlikely(XFS_TEST_ERROR(!sblock_ok, cur->bc_mp,
 329                         XFS_ERRTAG_BTREE_CHECK_SBLOCK,
 330                         XFS_RANDOM_BTREE_CHECK_SBLOCK))) {
 331                 if (bp)
 332                         xfs_buftrace("SBTREE ERROR", bp);
 333                 XFS_ERROR_REPORT("xfs_btree_check_sblock", XFS_ERRLEVEL_LOW,
 334                                  cur->bc_mp);
 335                 return XFS_ERROR(EFSCORRUPTED);
 336         }
 337         return 0;
 338 }
 339
 340 /*
 341  * Checking routine: check that (short) pointer is ok.
 342  */
 343 int                                     /* error (0 or EFSCORRUPTED) */
 344 xfs_btree_check_sptr(
 345         xfs_btree_cur_t *cur,           /* btree cursor */
 346         xfs_agblock_t   ptr,            /* btree block disk address */
 347         int             level)          /* btree block level */
 348 {
 349         xfs_buf_t       *agbp;          /* buffer for ag. freespace struct */
 350         xfs_agf_t       *agf;           /* ag. freespace structure */
 351
 352         agbp = cur->bc_private.a.agbp;
 353         agf = XFS_BUF_TO_AGF(agbp);
 354         XFS_WANT_CORRUPTED_RETURN(
 355                 level > 0 &&
 356                 ptr != NULLAGBLOCK && ptr != 0 &&
 357                 ptr < be32_to_cpu(agf->agf_length));
 358         return 0;
 359 }
 360
 361 /*
 362  * Delete the btree cursor.
 363  */
 364 void
 365 xfs_btree_del_cursor(
 366         xfs_btree_cur_t *cur,           /* btree cursor */
 367         int             error)          /* del because of error */
 368 {
 369         int             i;              /* btree level */
 370
 371         /*
 372          * Clear the buffer pointers, and release the buffers.
 373          * If we're doing this in the face of an error, we
 374          * need to make sure to inspect all of the entries
 375          * in the bc_bufs array for buffers to be unlocked.
 376          * This is because some of the btree code works from
 377          * level n down to 0, and if we get an error along
 378          * the way we won't have initialized all the entries
 379          * down to 0.
 380          */
 381         for (i = 0; i < cur->bc_nlevels; i++) {
 382                 if (cur->bc_bufs[i])
 383                         xfs_btree_setbuf(cur, i, NULL);
 384                 else if (!error)
 385                         break;
 386         }
 387         /*
 388          * Can't free a bmap cursor without having dealt with the
 389          * allocated indirect blocks' accounting.
 390          */
 391         ASSERT(cur->bc_btnum != XFS_BTNUM_BMAP ||
 392                cur->bc_private.b.allocated == 0);
 393         /*
 394          * Free the cursor.
 395          */
 396         kmem_zone_free(xfs_btree_cur_zone, cur);
 397 }
 398
 399 /*
 400  * Duplicate the btree cursor.
 401  * Allocate a new one, copy the record, re-get the buffers.
 402  */
 403 int                                     /* error */
 404 xfs_btree_dup_cursor(
 405         xfs_btree_cur_t *cur,           /* input cursor */
 406         xfs_btree_cur_t **ncur)         /* output cursor */
 407 {
 408         xfs_buf_t       *bp;            /* btree block's buffer pointer */
 409         int             error;          /* error return value */
 410         int             i;              /* level number of btree block */
 411         xfs_mount_t     *mp;            /* mount structure for filesystem */
 412         xfs_btree_cur_t *new;           /* new cursor value */
 413         xfs_trans_t     *tp;            /* transaction pointer, can be NULL */
 414
 415         tp = cur->bc_tp;
 416         mp = cur->bc_mp;
 417         /*
 418          * Allocate a new cursor like the old one.
 419          */
 420         new = xfs_btree_init_cursor(mp, tp, cur->bc_private.a.agbp,
 421                 cur->bc_private.a.agno, cur->bc_btnum, cur->bc_private.b.ip,
 422                 cur->bc_private.b.whichfork);
 423         /*
 424          * Copy the record currently in the cursor.
 425          */
 426         new->bc_rec = cur->bc_rec;
 427         /*
 428          * For each level current, re-get the buffer and copy the ptr value.
 429          */
 430         for (i = 0; i < new->bc_nlevels; i++) {
 431                 new->bc_ptrs[i] = cur->bc_ptrs[i];
 432                 new->bc_ra[i] = cur->bc_ra[i];
 433                 if ((bp = cur->bc_bufs[i])) {
 434                         if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
 435                                 XFS_BUF_ADDR(bp), mp->m_bsize, 0, &bp))) {
 436                                 xfs_btree_del_cursor(new, error);
 437                                 *ncur = NULL;
 438                                 return error;
 439                         }
 440                         new->bc_bufs[i] = bp;
 441                         ASSERT(bp);
 442                         ASSERT(!XFS_BUF_GETERROR(bp));
 443                 } else
 444                         new->bc_bufs[i] = NULL;
 445         }
 446         /*
 447          * For bmap btrees, copy the firstblock, flist, and flags values,
 448          * since init cursor doesn't get them.
 449          */
 450         if (new->bc_btnum == XFS_BTNUM_BMAP) {
 451                 new->bc_private.b.firstblock = cur->bc_private.b.firstblock;
 452                 new->bc_private.b.flist = cur->bc_private.b.flist;
 453                 new->bc_private.b.flags = cur->bc_private.b.flags;
 454         }
 455         *ncur = new;
 456         return 0;
 457 }
 458
 459 /*
 460  * Change the cursor to point to the first record at the given level.
 461  * Other levels are unaffected.
 462  */
 463 int                                     /* success=1, failure=0 */
 464 xfs_btree_firstrec(
 465         xfs_btree_cur_t         *cur,   /* btree cursor */
 466         int                     level)  /* level to change */
 467 {
 468         xfs_btree_block_t       *block; /* generic btree block pointer */
 469         xfs_buf_t               *bp;    /* buffer containing block */
 470
 471         /*
 472          * Get the block pointer for this level.
 473          */
 474         block = xfs_btree_get_block(cur, level, &bp);
 475         xfs_btree_check_block(cur, block, level, bp);
 476         /*
 477          * It's empty, there is no such record.
 478          */
 479         if (!block->bb_h.bb_numrecs)
 480                 return 0;
 481         /*
 482          * Set the ptr value to 1, that's the first record/key.
 483          */
 484         cur->bc_ptrs[level] = 1;
 485         return 1;
 486 }
 487
 488 /*
 489  * Retrieve the block pointer from the cursor at the given level.
 490  * This may be a bmap btree root or from a buffer.
 491  */
 492 STATIC xfs_btree_block_t *              /* generic btree block pointer */
 493 xfs_btree_get_block(
 494         xfs_btree_cur_t         *cur,   /* btree cursor */
 495         int                     level,  /* level in btree */
 496         xfs_buf_t               **bpp)  /* buffer containing the block */
 497 {
 498         xfs_btree_block_t       *block; /* return value */
 499         xfs_buf_t               *bp;    /* return buffer */
 500         xfs_ifork_t             *ifp;   /* inode fork pointer */
 501         int                     whichfork; /* data or attr fork */
 502
 503         if (cur->bc_btnum == XFS_BTNUM_BMAP && level == cur->bc_nlevels - 1) {
 504                 whichfork = cur->bc_private.b.whichfork;
 505                 ifp = XFS_IFORK_PTR(cur->bc_private.b.ip, whichfork);
 506                 block = (xfs_btree_block_t *)ifp->if_broot;
 507                 bp = NULL;
 508         } else {
 509                 bp = cur->bc_bufs[level];
 510                 block = XFS_BUF_TO_BLOCK(bp);
 511         }
 512         ASSERT(block != NULL);
 513         *bpp = bp;
 514         return block;
 515 }
 516
 517 /*
 518  * Get a buffer for the block, return it with no data read.
 519  * Long-form addressing.
 520  */
 521 xfs_buf_t *                             /* buffer for fsbno */
 522 xfs_btree_get_bufl(
 523         xfs_mount_t     *mp,            /* file system mount point */
 524         xfs_trans_t     *tp,            /* transaction pointer */
 525         xfs_fsblock_t   fsbno,          /* file system block number */
 526         uint            lock)           /* lock flags for get_buf */
 527 {
 528         xfs_buf_t       *bp;            /* buffer pointer (return value) */
 529         xfs_daddr_t             d;              /* real disk block address */
 530
 531         ASSERT(fsbno != NULLFSBLOCK);
 532         d = XFS_FSB_TO_DADDR(mp, fsbno);
 533         bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, lock);
 534         ASSERT(bp);
 535         ASSERT(!XFS_BUF_GETERROR(bp));
 536         return bp;
 537 }
 538
 539 /*
 540  * Get a buffer for the block, return it with no data read.
 541  * Short-form addressing.
 542  */
 543 xfs_buf_t *                             /* buffer for agno/agbno */
 544 xfs_btree_get_bufs(
 545         xfs_mount_t     *mp,            /* file system mount point */
 546         xfs_trans_t     *tp,            /* transaction pointer */
 547         xfs_agnumber_t  agno,           /* allocation group number */
 548         xfs_agblock_t   agbno,          /* allocation group block number */
 549         uint            lock)           /* lock flags for get_buf */
 550 {
 551         xfs_buf_t       *bp;            /* buffer pointer (return value) */
 552         xfs_daddr_t             d;              /* real disk block address */
 553
 554         ASSERT(agno != NULLAGNUMBER);
 555         ASSERT(agbno != NULLAGBLOCK);
 556         d = XFS_AGB_TO_DADDR(mp, agno, agbno);
 557         bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, lock);
 558         ASSERT(bp);
 559         ASSERT(!XFS_BUF_GETERROR(bp));
 560         return bp;
 561 }
 562
 563 /*
 564  * Allocate a new btree cursor.
 565  * The cursor is either for allocation (A) or bmap (B) or inodes (I).
 566  */
 567 xfs_btree_cur_t *                       /* new btree cursor */
 568 xfs_btree_init_cursor(
 569         xfs_mount_t     *mp,            /* file system mount point */
 570         xfs_trans_t     *tp,            /* transaction pointer */
 571         xfs_buf_t       *agbp,          /* (A only) buffer for agf structure */
 572                                         /* (I only) buffer for agi structure */
 573         xfs_agnumber_t  agno,           /* (AI only) allocation group number */
 574         xfs_btnum_t     btnum,          /* btree identifier */
 575         xfs_inode_t     *ip,            /* (B only) inode owning the btree */
 576         int             whichfork)      /* (B only) data or attr fork */
 577 {
 578         xfs_agf_t       *agf;           /* (A) allocation group freespace */
 579         xfs_agi_t       *agi;           /* (I) allocation group inodespace */
 580         xfs_btree_cur_t *cur;           /* return value */
 581         xfs_ifork_t     *ifp;           /* (I) inode fork pointer */
 582         int             nlevels=0;      /* number of levels in the btree */
 583
 584         ASSERT(xfs_btree_cur_zone != NULL);
 585         /*
 586          * Allocate a new cursor.
 587          */
 588         cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_SLEEP);
 589         /*
 590          * Deduce the number of btree levels from the arguments.
 591          */
 592         switch (btnum) {
 593         case XFS_BTNUM_BNO:
 594         case XFS_BTNUM_CNT:
 595                 agf = XFS_BUF_TO_AGF(agbp);
 596                 nlevels = be32_to_cpu(agf->agf_levels[btnum]);
 597                 break;
 598         case XFS_BTNUM_BMAP:
 599                 ifp = XFS_IFORK_PTR(ip, whichfork);
 600                 nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
 601                 break;
 602         case XFS_BTNUM_INO:
 603                 agi = XFS_BUF_TO_AGI(agbp);
 604                 nlevels = be32_to_cpu(agi->agi_level);
 605                 break;
 606         default:
 607                 ASSERT(0);
 608         }
 609         /*
 610          * Fill in the common fields.
 611          */
 612         cur->bc_tp = tp;
 613         cur->bc_mp = mp;
 614         cur->bc_nlevels = nlevels;
 615         cur->bc_btnum = btnum;
 616         cur->bc_blocklog = mp->m_sb.sb_blocklog;
 617         /*
 618          * Fill in private fields.
 619          */
 620         switch (btnum) {
 621         case XFS_BTNUM_BNO:
 622         case XFS_BTNUM_CNT:
 623                 /*
 624                  * Allocation btree fields.
 625                  */
 626                 cur->bc_private.a.agbp = agbp;
 627                 cur->bc_private.a.agno = agno;
 628                 break;
 629         case XFS_BTNUM_BMAP:
 630                 /*
 631                  * Bmap btree fields.
 632                  */
 633                 cur->bc_private.b.forksize = XFS_IFORK_SIZE(ip, whichfork);
 634                 cur->bc_private.b.ip = ip;
 635                 cur->bc_private.b.firstblock = NULLFSBLOCK;
 636                 cur->bc_private.b.flist = NULL;
 637                 cur->bc_private.b.allocated = 0;
 638                 cur->bc_private.b.flags = 0;
 639                 cur->bc_private.b.whichfork = whichfork;
 640                 break;
 641         case XFS_BTNUM_INO:
 642                 /*
 643                  * Inode allocation btree fields.
 644                  */
 645                 cur->bc_private.i.agbp = agbp;
 646                 cur->bc_private.i.agno = agno;
 647                 break;
 648         default:
 649                 ASSERT(0);
 650         }
 651         return cur;
 652 }
 653
 654 /*
 655  * Check for the cursor referring to the last block at the given level.
 656  */
 657 int                                     /* 1=is last block, 0=not last block */
 658 xfs_btree_islastblock(
 659         xfs_btree_cur_t         *cur,   /* btree cursor */
 660         int                     level)  /* level to check */
 661 {
 662         xfs_btree_block_t       *block; /* generic btree block pointer */
 663         xfs_buf_t               *bp;    /* buffer containing block */
 664
 665         block = xfs_btree_get_block(cur, level, &bp);
 666         xfs_btree_check_block(cur, block, level, bp);
 667         if (XFS_BTREE_LONG_PTRS(cur->bc_btnum))
 668                 return be64_to_cpu(block->bb_u.l.bb_rightsib) == NULLDFSBNO;
 669         else
 670                 return be32_to_cpu(block->bb_u.s.bb_rightsib) == NULLAGBLOCK;
 671 }
 672
 673 /*
 674  * Change the cursor to point to the last record in the current block
 675  * at the given level.  Other levels are unaffected.
 676  */
 677 int                                     /* success=1, failure=0 */
 678 xfs_btree_lastrec(
 679         xfs_btree_cur_t         *cur,   /* btree cursor */
 680         int                     level)  /* level to change */
 681 {
 682         xfs_btree_block_t       *block; /* generic btree block pointer */
 683         xfs_buf_t               *bp;    /* buffer containing block */
 684
 685         /*
 686          * Get the block pointer for this level.
 687          */
 688         block = xfs_btree_get_block(cur, level, &bp);
 689         xfs_btree_check_block(cur, block, level, bp);
 690         /*
 691          * It's empty, there is no such record.
 692          */
 693         if (!block->bb_h.bb_numrecs)
 694                 return 0;
 695         /*
 696          * Set the ptr value to numrecs, that's the last record/key.
 697          */
 698         cur->bc_ptrs[level] = be16_to_cpu(block->bb_h.bb_numrecs);
 699         return 1;
 700 }
 701
 702 /*
 703  * Compute first and last byte offsets for the fields given.
 704  * Interprets the offsets table, which contains struct field offsets.
 705  */
 706 void
 707 xfs_btree_offsets(
 708         __int64_t       fields,         /* bitmask of fields */
 709         const short     *offsets,       /* table of field offsets */
 710         int             nbits,          /* number of bits to inspect */
 711         int             *first,         /* output: first byte offset */
 712         int             *last)          /* output: last byte offset */
 713 {
 714         int             i;              /* current bit number */
 715         __int64_t       imask;          /* mask for current bit number */
 716
 717         ASSERT(fields != 0);
 718         /*
 719          * Find the lowest bit, so the first byte offset.
 720          */
 721         for (i = 0, imask = 1LL; ; i++, imask <<= 1) {
 722                 if (imask & fields) {
 723                         *first = offsets[i];
 724                         break;
 725                 }
 726         }
 727         /*
 728          * Find the highest bit, so the last byte offset.
 729          */
 730         for (i = nbits - 1, imask = 1LL << i; ; i--, imask >>= 1) {
 731                 if (imask & fields) {
 732                         *last = offsets[i + 1] - 1;
 733                         break;
 734                 }
 735         }
 736 }
 737
 738 /*
 739  * Get a buffer for the block, return it read in.
 740  * Long-form addressing.
 741  */
 742 int                                     /* error */
 743 xfs_btree_read_bufl(
 744         xfs_mount_t     *mp,            /* file system mount point */
 745         xfs_trans_t     *tp,            /* transaction pointer */
 746         xfs_fsblock_t   fsbno,          /* file system block number */
 747         uint            lock,           /* lock flags for read_buf */
 748         xfs_buf_t       **bpp,          /* buffer for fsbno */
 749         int             refval)         /* ref count value for buffer */
 750 {
 751         xfs_buf_t       *bp;            /* return value */
 752         xfs_daddr_t             d;              /* real disk block address */
 753         int             error;
 754
 755         ASSERT(fsbno != NULLFSBLOCK);
 756         d = XFS_FSB_TO_DADDR(mp, fsbno);
 757         if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
 758                         mp->m_bsize, lock, &bp))) {
 759                 return error;
 760         }
 761         ASSERT(!bp || !XFS_BUF_GETERROR(bp));
 762         if (bp != NULL) {
 763                 XFS_BUF_SET_VTYPE_REF(bp, B_FS_MAP, refval);
 764         }
 765         *bpp = bp;
 766         return 0;
 767 }
 768
 769 /*
 770  * Get a buffer for the block, return it read in.
 771  * Short-form addressing.
 772  */
 773 int                                     /* error */
 774 xfs_btree_read_bufs(
 775         xfs_mount_t     *mp,            /* file system mount point */
 776         xfs_trans_t     *tp,            /* transaction pointer */
 777         xfs_agnumber_t  agno,           /* allocation group number */
 778         xfs_agblock_t   agbno,          /* allocation group block number */
 779         uint            lock,           /* lock flags for read_buf */
 780         xfs_buf_t       **bpp,          /* buffer for agno/agbno */
 781         int             refval)         /* ref count value for buffer */
 782 {
 783         xfs_buf_t       *bp;            /* return value */
 784         xfs_daddr_t     d;              /* real disk block address */
 785         int             error;
 786
 787         ASSERT(agno != NULLAGNUMBER);
 788         ASSERT(agbno != NULLAGBLOCK);
 789         d = XFS_AGB_TO_DADDR(mp, agno, agbno);
 790         if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
 791                                         mp->m_bsize, lock, &bp))) {
 792                 return error;
 793         }
 794         ASSERT(!bp || !XFS_BUF_GETERROR(bp));
 795         if (bp != NULL) {
 796                 switch (refval) {
 797                 case XFS_ALLOC_BTREE_REF:
 798                         XFS_BUF_SET_VTYPE_REF(bp, B_FS_MAP, refval);
 799                         break;
 800                 case XFS_INO_BTREE_REF:
 801                         XFS_BUF_SET_VTYPE_REF(bp, B_FS_INOMAP, refval);
 802                         break;
 803                 }
 804         }
 805         *bpp = bp;
 806         return 0;
 807 }
 808
 809 /*
 810  * Read-ahead the block, don't wait for it, don't return a buffer.
 811  * Long-form addressing.
 812  */
 813 /* ARGSUSED */
 814 void
 815 xfs_btree_reada_bufl(
 816         xfs_mount_t     *mp,            /* file system mount point */
 817         xfs_fsblock_t   fsbno,          /* file system block number */
 818         xfs_extlen_t    count)          /* count of filesystem blocks */
 819 {
 820         xfs_daddr_t             d;
 821
 822         ASSERT(fsbno != NULLFSBLOCK);
 823         d = XFS_FSB_TO_DADDR(mp, fsbno);
 824         xfs_baread(mp->m_ddev_targp, d, mp->m_bsize * count);
 825 }
 826
 827 /*
 828  * Read-ahead the block, don't wait for it, don't return a buffer.
 829  * Short-form addressing.
 830  */
 831 /* ARGSUSED */
 832 void
 833 xfs_btree_reada_bufs(
 834         xfs_mount_t     *mp,            /* file system mount point */
 835         xfs_agnumber_t  agno,           /* allocation group number */
 836         xfs_agblock_t   agbno,          /* allocation group block number */
 837         xfs_extlen_t    count)          /* count of filesystem blocks */
 838 {
 839         xfs_daddr_t             d;
 840
 841         ASSERT(agno != NULLAGNUMBER);
 842         ASSERT(agbno != NULLAGBLOCK);
 843         d = XFS_AGB_TO_DADDR(mp, agno, agbno);
 844         xfs_baread(mp->m_ddev_targp, d, mp->m_bsize * count);
 845 }
 846
 847 /*
 848  * Read-ahead btree blocks, at the given level.
 849  * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
 850  */
 851 int
 852 xfs_btree_readahead_core(
 853         xfs_btree_cur_t         *cur,           /* btree cursor */
 854         int                     lev,            /* level in btree */
 855         int                     lr)             /* left/right bits */
 856 {
 857         xfs_alloc_block_t       *a;
 858         xfs_bmbt_block_t        *b;
 859         xfs_inobt_block_t       *i;
 860         int                     rval = 0;
 861
 862         ASSERT(cur->bc_bufs[lev] != NULL);
 863         cur->bc_ra[lev] |= lr;
 864         switch (cur->bc_btnum) {
 865         case XFS_BTNUM_BNO:
 866         case XFS_BTNUM_CNT:
 867                 a = XFS_BUF_TO_ALLOC_BLOCK(cur->bc_bufs[lev]);
 868                 if ((lr & XFS_BTCUR_LEFTRA) && be32_to_cpu(a->bb_leftsib) != NULLAGBLOCK) {
 869                         xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
 870                                 be32_to_cpu(a->bb_leftsib), 1);
 871                         rval++;
 872                 }
 873                 if ((lr & XFS_BTCUR_RIGHTRA) && be32_to_cpu(a->bb_rightsib) != NULLAGBLOCK) {
 874                         xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
 875                                 be32_to_cpu(a->bb_rightsib), 1);
 876                         rval++;
 877                 }
 878                 break;
 879         case XFS_BTNUM_BMAP:
 880                 b = XFS_BUF_TO_BMBT_BLOCK(cur->bc_bufs[lev]);
 881                 if ((lr & XFS_BTCUR_LEFTRA) && be64_to_cpu(b->bb_leftsib) != NULLDFSBNO) {
 882                         xfs_btree_reada_bufl(cur->bc_mp, be64_to_cpu(b->bb_leftsib), 1);
 883                         rval++;
 884                 }
 885                 if ((lr & XFS_BTCUR_RIGHTRA) && be64_to_cpu(b->bb_rightsib) != NULLDFSBNO) {
 886                         xfs_btree_reada_bufl(cur->bc_mp, be64_to_cpu(b->bb_rightsib), 1);
 887                         rval++;
 888                 }
 889                 break;
 890         case XFS_BTNUM_INO:
 891                 i = XFS_BUF_TO_INOBT_BLOCK(cur->bc_bufs[lev]);
 892                 if ((lr & XFS_BTCUR_LEFTRA) && be32_to_cpu(i->bb_leftsib) != NULLAGBLOCK) {
 893                         xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.i.agno,
 894                                 be32_to_cpu(i->bb_leftsib), 1);
 895                         rval++;
 896                 }
 897                 if ((lr & XFS_BTCUR_RIGHTRA) && be32_to_cpu(i->bb_rightsib) != NULLAGBLOCK) {
 898                         xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.i.agno,
 899                                 be32_to_cpu(i->bb_rightsib), 1);
 900                         rval++;
 901                 }
 902                 break;
 903         default:
 904                 ASSERT(0);
 905         }
 906         return rval;
 907 }
 908
 909 /*
 910  * Set the buffer for level "lev" in the cursor to bp, releasing
 911  * any previous buffer.
 912  */
 913 void
 914 xfs_btree_setbuf(
 915         xfs_btree_cur_t         *cur,   /* btree cursor */
 916         int                     lev,    /* level in btree */
 917         xfs_buf_t               *bp)    /* new buffer to set */
 918 {
 919         xfs_btree_block_t       *b;     /* btree block */
 920         xfs_buf_t               *obp;   /* old buffer pointer */
 921
 922         obp = cur->bc_bufs[lev];
 923         if (obp)
 924                 xfs_trans_brelse(cur->bc_tp, obp);
 925         cur->bc_bufs[lev] = bp;
 926         cur->bc_ra[lev] = 0;
 927         if (!bp)
 928                 return;
 929         b = XFS_BUF_TO_BLOCK(bp);
 930         if (XFS_BTREE_LONG_PTRS(cur->bc_btnum)) {
 931                 if (be64_to_cpu(b->bb_u.l.bb_leftsib) == NULLDFSBNO)
 932                         cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
 933                 if (be64_to_cpu(b->bb_u.l.bb_rightsib) == NULLDFSBNO)
 934                         cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
 935         } else {
 936                 if (be32_to_cpu(b->bb_u.s.bb_leftsib) == NULLAGBLOCK)
 937                         cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
 938                 if (be32_to_cpu(b->bb_u.s.bb_rightsib) == NULLAGBLOCK)
 939                         cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
 940         }
 941 }