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_trans.h"
  24 #include "xfs_sb.h"
  25 #include "xfs_ag.h"
  26 #include "xfs_mount.h"
  27 #include "xfs_bmap_btree.h"
  28 #include "xfs_alloc_btree.h"
  29 #include "xfs_ialloc_btree.h"
  30 #include "xfs_dinode.h"
  31 #include "xfs_inode.h"
  32 #include "xfs_inode_item.h"
  33 #include "xfs_btree.h"
  34 #include "xfs_error.h"
  35 #include "xfs_trace.h"
  36
  37 /*
  38  * Cursor allocation zone.
  39  */
  40 kmem_zone_t     *xfs_btree_cur_zone;
  41
  42 /*
  43  * Btree magic numbers.
  44  */
  45 const __uint32_t xfs_magics[XFS_BTNUM_MAX] = {
  46         XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, XFS_BMAP_MAGIC, XFS_IBT_MAGIC
  47 };
  48
  49
  50 STATIC int                              /* error (0 or EFSCORRUPTED) */
  51 xfs_btree_check_lblock(
  52         struct xfs_btree_cur    *cur,   /* btree cursor */
  53         struct xfs_btree_block  *block, /* btree long form block pointer */
  54         int                     level,  /* level of the btree block */
  55         struct xfs_buf          *bp)    /* buffer for block, if any */
  56 {
  57         int                     lblock_ok; /* block passes checks */
  58         struct xfs_mount        *mp;    /* file system mount point */
  59
  60         mp = cur->bc_mp;
  61         lblock_ok =
  62                 be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
  63                 be16_to_cpu(block->bb_level) == level &&
  64                 be16_to_cpu(block->bb_numrecs) <=
  65                         cur->bc_ops->get_maxrecs(cur, level) &&
  66                 block->bb_u.l.bb_leftsib &&
  67                 (block->bb_u.l.bb_leftsib == cpu_to_be64(NULLDFSBNO) ||
  68                  XFS_FSB_SANITY_CHECK(mp,
  69                         be64_to_cpu(block->bb_u.l.bb_leftsib))) &&
  70                 block->bb_u.l.bb_rightsib &&
  71                 (block->bb_u.l.bb_rightsib == cpu_to_be64(NULLDFSBNO) ||
  72                  XFS_FSB_SANITY_CHECK(mp,
  73                         be64_to_cpu(block->bb_u.l.bb_rightsib)));
  74         if (unlikely(XFS_TEST_ERROR(!lblock_ok, mp,
  75                         XFS_ERRTAG_BTREE_CHECK_LBLOCK,
  76                         XFS_RANDOM_BTREE_CHECK_LBLOCK))) {
  77                 if (bp)
  78                         trace_xfs_btree_corrupt(bp, _RET_IP_);
  79                 XFS_ERROR_REPORT("xfs_btree_check_lblock", XFS_ERRLEVEL_LOW,
  80                                  mp);
  81                 return XFS_ERROR(EFSCORRUPTED);
  82         }
  83         return 0;
  84 }
  85
  86 STATIC int                              /* error (0 or EFSCORRUPTED) */
  87 xfs_btree_check_sblock(
  88         struct xfs_btree_cur    *cur,   /* btree cursor */
  89         struct xfs_btree_block  *block, /* btree short form block pointer */
  90         int                     level,  /* level of the btree block */
  91         struct xfs_buf          *bp)    /* buffer containing block */
  92 {
  93         struct xfs_buf          *agbp;  /* buffer for ag. freespace struct */
  94         struct xfs_agf          *agf;   /* ag. freespace structure */
  95         xfs_agblock_t           agflen; /* native ag. freespace length */
  96         int                     sblock_ok; /* block passes checks */
  97
  98         agbp = cur->bc_private.a.agbp;
  99         agf = XFS_BUF_TO_AGF(agbp);
 100         agflen = be32_to_cpu(agf->agf_length);
 101         sblock_ok =
 102                 be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
 103                 be16_to_cpu(block->bb_level) == level &&
 104                 be16_to_cpu(block->bb_numrecs) <=
 105                         cur->bc_ops->get_maxrecs(cur, level) &&
 106                 (block->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK) ||
 107                  be32_to_cpu(block->bb_u.s.bb_leftsib) < agflen) &&
 108                 block->bb_u.s.bb_leftsib &&
 109                 (block->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK) ||
 110                  be32_to_cpu(block->bb_u.s.bb_rightsib) < agflen) &&
 111                 block->bb_u.s.bb_rightsib;
 112         if (unlikely(XFS_TEST_ERROR(!sblock_ok, cur->bc_mp,
 113                         XFS_ERRTAG_BTREE_CHECK_SBLOCK,
 114                         XFS_RANDOM_BTREE_CHECK_SBLOCK))) {
 115                 if (bp)
 116                         trace_xfs_btree_corrupt(bp, _RET_IP_);
 117                 XFS_CORRUPTION_ERROR("xfs_btree_check_sblock",
 118                         XFS_ERRLEVEL_LOW, cur->bc_mp, block);
 119                 return XFS_ERROR(EFSCORRUPTED);
 120         }
 121         return 0;
 122 }
 123
 124 /*
 125  * Debug routine: check that block header is ok.
 126  */
 127 int
 128 xfs_btree_check_block(
 129         struct xfs_btree_cur    *cur,   /* btree cursor */
 130         struct xfs_btree_block  *block, /* generic btree block pointer */
 131         int                     level,  /* level of the btree block */
 132         struct xfs_buf          *bp)    /* buffer containing block, if any */
 133 {
 134         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 135                 return xfs_btree_check_lblock(cur, block, level, bp);
 136         else
 137                 return xfs_btree_check_sblock(cur, block, level, bp);
 138 }
 139
 140 /*
 141  * Check that (long) pointer is ok.
 142  */
 143 int                                     /* error (0 or EFSCORRUPTED) */
 144 xfs_btree_check_lptr(
 145         struct xfs_btree_cur    *cur,   /* btree cursor */
 146         xfs_dfsbno_t            bno,    /* btree block disk address */
 147         int                     level)  /* btree block level */
 148 {
 149         XFS_WANT_CORRUPTED_RETURN(
 150                 level > 0 &&
 151                 bno != NULLDFSBNO &&
 152                 XFS_FSB_SANITY_CHECK(cur->bc_mp, bno));
 153         return 0;
 154 }
 155
 156 #ifdef DEBUG
 157 /*
 158  * Check that (short) pointer is ok.
 159  */
 160 STATIC int                              /* error (0 or EFSCORRUPTED) */
 161 xfs_btree_check_sptr(
 162         struct xfs_btree_cur    *cur,   /* btree cursor */
 163         xfs_agblock_t           bno,    /* btree block disk address */
 164         int                     level)  /* btree block level */
 165 {
 166         xfs_agblock_t           agblocks = cur->bc_mp->m_sb.sb_agblocks;
 167
 168         XFS_WANT_CORRUPTED_RETURN(
 169                 level > 0 &&
 170                 bno != NULLAGBLOCK &&
 171                 bno != 0 &&
 172                 bno < agblocks);
 173         return 0;
 174 }
 175
 176 /*
 177  * Check that block ptr is ok.
 178  */
 179 STATIC int                              /* error (0 or EFSCORRUPTED) */
 180 xfs_btree_check_ptr(
 181         struct xfs_btree_cur    *cur,   /* btree cursor */
 182         union xfs_btree_ptr     *ptr,   /* btree block disk address */
 183         int                     index,  /* offset from ptr to check */
 184         int                     level)  /* btree block level */
 185 {
 186         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 187                 return xfs_btree_check_lptr(cur,
 188                                 be64_to_cpu((&ptr->l)[index]), level);
 189         } else {
 190                 return xfs_btree_check_sptr(cur,
 191                                 be32_to_cpu((&ptr->s)[index]), level);
 192         }
 193 }
 194 #endif
 195
 196 /*
 197  * Delete the btree cursor.
 198  */
 199 void
 200 xfs_btree_del_cursor(
 201         xfs_btree_cur_t *cur,           /* btree cursor */
 202         int             error)          /* del because of error */
 203 {
 204         int             i;              /* btree level */
 205
 206         /*
 207          * Clear the buffer pointers, and release the buffers.
 208          * If we're doing this in the face of an error, we
 209          * need to make sure to inspect all of the entries
 210          * in the bc_bufs array for buffers to be unlocked.
 211          * This is because some of the btree code works from
 212          * level n down to 0, and if we get an error along
 213          * the way we won't have initialized all the entries
 214          * down to 0.
 215          */
 216         for (i = 0; i < cur->bc_nlevels; i++) {
 217                 if (cur->bc_bufs[i])
 218                         xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[i]);
 219                 else if (!error)
 220                         break;
 221         }
 222         /*
 223          * Can't free a bmap cursor without having dealt with the
 224          * allocated indirect blocks' accounting.
 225          */
 226         ASSERT(cur->bc_btnum != XFS_BTNUM_BMAP ||
 227                cur->bc_private.b.allocated == 0);
 228         /*
 229          * Free the cursor.
 230          */
 231         kmem_zone_free(xfs_btree_cur_zone, cur);
 232 }
 233
 234 /*
 235  * Duplicate the btree cursor.
 236  * Allocate a new one, copy the record, re-get the buffers.
 237  */
 238 int                                     /* error */
 239 xfs_btree_dup_cursor(
 240         xfs_btree_cur_t *cur,           /* input cursor */
 241         xfs_btree_cur_t **ncur)         /* output cursor */
 242 {
 243         xfs_buf_t       *bp;            /* btree block's buffer pointer */
 244         int             error;          /* error return value */
 245         int             i;              /* level number of btree block */
 246         xfs_mount_t     *mp;            /* mount structure for filesystem */
 247         xfs_btree_cur_t *new;           /* new cursor value */
 248         xfs_trans_t     *tp;            /* transaction pointer, can be NULL */
 249
 250         tp = cur->bc_tp;
 251         mp = cur->bc_mp;
 252
 253         /*
 254          * Allocate a new cursor like the old one.
 255          */
 256         new = cur->bc_ops->dup_cursor(cur);
 257
 258         /*
 259          * Copy the record currently in the cursor.
 260          */
 261         new->bc_rec = cur->bc_rec;
 262
 263         /*
 264          * For each level current, re-get the buffer and copy the ptr value.
 265          */
 266         for (i = 0; i < new->bc_nlevels; i++) {
 267                 new->bc_ptrs[i] = cur->bc_ptrs[i];
 268                 new->bc_ra[i] = cur->bc_ra[i];
 269                 if ((bp = cur->bc_bufs[i])) {
 270                         if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
 271                                 XFS_BUF_ADDR(bp), mp->m_bsize, 0, &bp))) {
 272                                 xfs_btree_del_cursor(new, error);
 273                                 *ncur = NULL;
 274                                 return error;
 275                         }
 276                         new->bc_bufs[i] = bp;
 277                         ASSERT(!xfs_buf_geterror(bp));
 278                 } else
 279                         new->bc_bufs[i] = NULL;
 280         }
 281         *ncur = new;
 282         return 0;
 283 }
 284
 285 /*
 286  * XFS btree block layout and addressing:
 287  *
 288  * There are two types of blocks in the btree: leaf and non-leaf blocks.
 289  *
 290  * The leaf record start with a header then followed by records containing
 291  * the values.  A non-leaf block also starts with the same header, and
 292  * then first contains lookup keys followed by an equal number of pointers
 293  * to the btree blocks at the previous level.
 294  *
 295  *              +--------+-------+-------+-------+-------+-------+-------+
 296  * Leaf:        | header | rec 1 | rec 2 | rec 3 | rec 4 | rec 5 | rec N |
 297  *              +--------+-------+-------+-------+-------+-------+-------+
 298  *
 299  *              +--------+-------+-------+-------+-------+-------+-------+
 300  * Non-Leaf:    | header | key 1 | key 2 | key N | ptr 1 | ptr 2 | ptr N |
 301  *              +--------+-------+-------+-------+-------+-------+-------+
 302  *
 303  * The header is called struct xfs_btree_block for reasons better left unknown
 304  * and comes in different versions for short (32bit) and long (64bit) block
 305  * pointers.  The record and key structures are defined by the btree instances
 306  * and opaque to the btree core.  The block pointers are simple disk endian
 307  * integers, available in a short (32bit) and long (64bit) variant.
 308  *
 309  * The helpers below calculate the offset of a given record, key or pointer
 310  * into a btree block (xfs_btree_*_offset) or return a pointer to the given
 311  * record, key or pointer (xfs_btree_*_addr).  Note that all addressing
 312  * inside the btree block is done using indices starting at one, not zero!
 313  */
 314
 315 /*
 316  * Return size of the btree block header for this btree instance.
 317  */
 318 static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur)
 319 {
 320         return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
 321                 XFS_BTREE_LBLOCK_LEN :
 322                 XFS_BTREE_SBLOCK_LEN;
 323 }
 324
 325 /*
 326  * Return size of btree block pointers for this btree instance.
 327  */
 328 static inline size_t xfs_btree_ptr_len(struct xfs_btree_cur *cur)
 329 {
 330         return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
 331                 sizeof(__be64) : sizeof(__be32);
 332 }
 333
 334 /*
 335  * Calculate offset of the n-th record in a btree block.
 336  */
 337 STATIC size_t
 338 xfs_btree_rec_offset(
 339         struct xfs_btree_cur    *cur,
 340         int                     n)
 341 {
 342         return xfs_btree_block_len(cur) +
 343                 (n - 1) * cur->bc_ops->rec_len;
 344 }
 345
 346 /*
 347  * Calculate offset of the n-th key in a btree block.
 348  */
 349 STATIC size_t
 350 xfs_btree_key_offset(
 351         struct xfs_btree_cur    *cur,
 352         int                     n)
 353 {
 354         return xfs_btree_block_len(cur) +
 355                 (n - 1) * cur->bc_ops->key_len;
 356 }
 357
 358 /*
 359  * Calculate offset of the n-th block pointer in a btree block.
 360  */
 361 STATIC size_t
 362 xfs_btree_ptr_offset(
 363         struct xfs_btree_cur    *cur,
 364         int                     n,
 365         int                     level)
 366 {
 367         return xfs_btree_block_len(cur) +
 368                 cur->bc_ops->get_maxrecs(cur, level) * cur->bc_ops->key_len +
 369                 (n - 1) * xfs_btree_ptr_len(cur);
 370 }
 371
 372 /*
 373  * Return a pointer to the n-th record in the btree block.
 374  */
 375 STATIC union xfs_btree_rec *
 376 xfs_btree_rec_addr(
 377         struct xfs_btree_cur    *cur,
 378         int                     n,
 379         struct xfs_btree_block  *block)
 380 {
 381         return (union xfs_btree_rec *)
 382                 ((char *)block + xfs_btree_rec_offset(cur, n));
 383 }
 384
 385 /*
 386  * Return a pointer to the n-th key in the btree block.
 387  */
 388 STATIC union xfs_btree_key *
 389 xfs_btree_key_addr(
 390         struct xfs_btree_cur    *cur,
 391         int                     n,
 392         struct xfs_btree_block  *block)
 393 {
 394         return (union xfs_btree_key *)
 395                 ((char *)block + xfs_btree_key_offset(cur, n));
 396 }
 397
 398 /*
 399  * Return a pointer to the n-th block pointer in the btree block.
 400  */
 401 STATIC union xfs_btree_ptr *
 402 xfs_btree_ptr_addr(
 403         struct xfs_btree_cur    *cur,
 404         int                     n,
 405         struct xfs_btree_block  *block)
 406 {
 407         int                     level = xfs_btree_get_level(block);
 408
 409         ASSERT(block->bb_level != 0);
 410
 411         return (union xfs_btree_ptr *)
 412                 ((char *)block + xfs_btree_ptr_offset(cur, n, level));
 413 }
 414
 415 /*
 416  * Get a the root block which is stored in the inode.
 417  *
 418  * For now this btree implementation assumes the btree root is always
 419  * stored in the if_broot field of an inode fork.
 420  */
 421 STATIC struct xfs_btree_block *
 422 xfs_btree_get_iroot(
 423        struct xfs_btree_cur    *cur)
 424 {
 425        struct xfs_ifork        *ifp;
 426
 427        ifp = XFS_IFORK_PTR(cur->bc_private.b.ip, cur->bc_private.b.whichfork);
 428        return (struct xfs_btree_block *)ifp->if_broot;
 429 }
 430
 431 /*
 432  * Retrieve the block pointer from the cursor at the given level.
 433  * This may be an inode btree root or from a buffer.
 434  */
 435 STATIC struct xfs_btree_block *         /* generic btree block pointer */
 436 xfs_btree_get_block(
 437         struct xfs_btree_cur    *cur,   /* btree cursor */
 438         int                     level,  /* level in btree */
 439         struct xfs_buf          **bpp)  /* buffer containing the block */
 440 {
 441         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
 442             (level == cur->bc_nlevels - 1)) {
 443                 *bpp = NULL;
 444                 return xfs_btree_get_iroot(cur);
 445         }
 446
 447         *bpp = cur->bc_bufs[level];
 448         return XFS_BUF_TO_BLOCK(*bpp);
 449 }
 450
 451 /*
 452  * Get a buffer for the block, return it with no data read.
 453  * Long-form addressing.
 454  */
 455 xfs_buf_t *                             /* buffer for fsbno */
 456 xfs_btree_get_bufl(
 457         xfs_mount_t     *mp,            /* file system mount point */
 458         xfs_trans_t     *tp,            /* transaction pointer */
 459         xfs_fsblock_t   fsbno,          /* file system block number */
 460         uint            lock)           /* lock flags for get_buf */
 461 {
 462         xfs_buf_t       *bp;            /* buffer pointer (return value) */
 463         xfs_daddr_t             d;              /* real disk block address */
 464
 465         ASSERT(fsbno != NULLFSBLOCK);
 466         d = XFS_FSB_TO_DADDR(mp, fsbno);
 467         bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, lock);
 468         ASSERT(!xfs_buf_geterror(bp));
 469         return bp;
 470 }
 471
 472 /*
 473  * Get a buffer for the block, return it with no data read.
 474  * Short-form addressing.
 475  */
 476 xfs_buf_t *                             /* buffer for agno/agbno */
 477 xfs_btree_get_bufs(
 478         xfs_mount_t     *mp,            /* file system mount point */
 479         xfs_trans_t     *tp,            /* transaction pointer */
 480         xfs_agnumber_t  agno,           /* allocation group number */
 481         xfs_agblock_t   agbno,          /* allocation group block number */
 482         uint            lock)           /* lock flags for get_buf */
 483 {
 484         xfs_buf_t       *bp;            /* buffer pointer (return value) */
 485         xfs_daddr_t             d;              /* real disk block address */
 486
 487         ASSERT(agno != NULLAGNUMBER);
 488         ASSERT(agbno != NULLAGBLOCK);
 489         d = XFS_AGB_TO_DADDR(mp, agno, agbno);
 490         bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, lock);
 491         ASSERT(!xfs_buf_geterror(bp));
 492         return bp;
 493 }
 494
 495 /*
 496  * Check for the cursor referring to the last block at the given level.
 497  */
 498 int                                     /* 1=is last block, 0=not last block */
 499 xfs_btree_islastblock(
 500         xfs_btree_cur_t         *cur,   /* btree cursor */
 501         int                     level)  /* level to check */
 502 {
 503         struct xfs_btree_block  *block; /* generic btree block pointer */
 504         xfs_buf_t               *bp;    /* buffer containing block */
 505
 506         block = xfs_btree_get_block(cur, level, &bp);
 507         xfs_btree_check_block(cur, block, level, bp);
 508         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 509                 return block->bb_u.l.bb_rightsib == cpu_to_be64(NULLDFSBNO);
 510         else
 511                 return block->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK);
 512 }
 513
 514 /*
 515  * Change the cursor to point to the first record at the given level.
 516  * Other levels are unaffected.
 517  */
 518 STATIC int                              /* success=1, failure=0 */
 519 xfs_btree_firstrec(
 520         xfs_btree_cur_t         *cur,   /* btree cursor */
 521         int                     level)  /* level to change */
 522 {
 523         struct xfs_btree_block  *block; /* generic btree block pointer */
 524         xfs_buf_t               *bp;    /* buffer containing block */
 525
 526         /*
 527          * Get the block pointer for this level.
 528          */
 529         block = xfs_btree_get_block(cur, level, &bp);
 530         xfs_btree_check_block(cur, block, level, bp);
 531         /*
 532          * It's empty, there is no such record.
 533          */
 534         if (!block->bb_numrecs)
 535                 return 0;
 536         /*
 537          * Set the ptr value to 1, that's the first record/key.
 538          */
 539         cur->bc_ptrs[level] = 1;
 540         return 1;
 541 }
 542
 543 /*
 544  * Change the cursor to point to the last record in the current block
 545  * at the given level.  Other levels are unaffected.
 546  */
 547 STATIC int                              /* success=1, failure=0 */
 548 xfs_btree_lastrec(
 549         xfs_btree_cur_t         *cur,   /* btree cursor */
 550         int                     level)  /* level to change */
 551 {
 552         struct xfs_btree_block  *block; /* generic btree block pointer */
 553         xfs_buf_t               *bp;    /* buffer containing block */
 554
 555         /*
 556          * Get the block pointer for this level.
 557          */
 558         block = xfs_btree_get_block(cur, level, &bp);
 559         xfs_btree_check_block(cur, block, level, bp);
 560         /*
 561          * It's empty, there is no such record.
 562          */
 563         if (!block->bb_numrecs)
 564                 return 0;
 565         /*
 566          * Set the ptr value to numrecs, that's the last record/key.
 567          */
 568         cur->bc_ptrs[level] = be16_to_cpu(block->bb_numrecs);
 569         return 1;
 570 }
 571
 572 /*
 573  * Compute first and last byte offsets for the fields given.
 574  * Interprets the offsets table, which contains struct field offsets.
 575  */
 576 void
 577 xfs_btree_offsets(
 578         __int64_t       fields,         /* bitmask of fields */
 579         const short     *offsets,       /* table of field offsets */
 580         int             nbits,          /* number of bits to inspect */
 581         int             *first,         /* output: first byte offset */
 582         int             *last)          /* output: last byte offset */
 583 {
 584         int             i;              /* current bit number */
 585         __int64_t       imask;          /* mask for current bit number */
 586
 587         ASSERT(fields != 0);
 588         /*
 589          * Find the lowest bit, so the first byte offset.
 590          */
 591         for (i = 0, imask = 1LL; ; i++, imask <<= 1) {
 592                 if (imask & fields) {
 593                         *first = offsets[i];
 594                         break;
 595                 }
 596         }
 597         /*
 598          * Find the highest bit, so the last byte offset.
 599          */
 600         for (i = nbits - 1, imask = 1LL << i; ; i--, imask >>= 1) {
 601                 if (imask & fields) {
 602                         *last = offsets[i + 1] - 1;
 603                         break;
 604                 }
 605         }
 606 }
 607
 608 /*
 609  * Get a buffer for the block, return it read in.
 610  * Long-form addressing.
 611  */
 612 int                                     /* error */
 613 xfs_btree_read_bufl(
 614         xfs_mount_t     *mp,            /* file system mount point */
 615         xfs_trans_t     *tp,            /* transaction pointer */
 616         xfs_fsblock_t   fsbno,          /* file system block number */
 617         uint            lock,           /* lock flags for read_buf */
 618         xfs_buf_t       **bpp,          /* buffer for fsbno */
 619         int             refval)         /* ref count value for buffer */
 620 {
 621         xfs_buf_t       *bp;            /* return value */
 622         xfs_daddr_t             d;              /* real disk block address */
 623         int             error;
 624
 625         ASSERT(fsbno != NULLFSBLOCK);
 626         d = XFS_FSB_TO_DADDR(mp, fsbno);
 627         if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
 628                         mp->m_bsize, lock, &bp))) {
 629                 return error;
 630         }
 631         ASSERT(!xfs_buf_geterror(bp));
 632         if (bp)
 633                 xfs_buf_set_ref(bp, refval);
 634         *bpp = bp;
 635         return 0;
 636 }
 637
 638 /*
 639  * Read-ahead the block, don't wait for it, don't return a buffer.
 640  * Long-form addressing.
 641  */
 642 /* ARGSUSED */
 643 void
 644 xfs_btree_reada_bufl(
 645         xfs_mount_t     *mp,            /* file system mount point */
 646         xfs_fsblock_t   fsbno,          /* file system block number */
 647         xfs_extlen_t    count)          /* count of filesystem blocks */
 648 {
 649         xfs_daddr_t             d;
 650
 651         ASSERT(fsbno != NULLFSBLOCK);
 652         d = XFS_FSB_TO_DADDR(mp, fsbno);
 653         xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count);
 654 }
 655
 656 /*
 657  * Read-ahead the block, don't wait for it, don't return a buffer.
 658  * Short-form addressing.
 659  */
 660 /* ARGSUSED */
 661 void
 662 xfs_btree_reada_bufs(
 663         xfs_mount_t     *mp,            /* file system mount point */
 664         xfs_agnumber_t  agno,           /* allocation group number */
 665         xfs_agblock_t   agbno,          /* allocation group block number */
 666         xfs_extlen_t    count)          /* count of filesystem blocks */
 667 {
 668         xfs_daddr_t             d;
 669
 670         ASSERT(agno != NULLAGNUMBER);
 671         ASSERT(agbno != NULLAGBLOCK);
 672         d = XFS_AGB_TO_DADDR(mp, agno, agbno);
 673         xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count);
 674 }
 675
 676 STATIC int
 677 xfs_btree_readahead_lblock(
 678         struct xfs_btree_cur    *cur,
 679         int                     lr,
 680         struct xfs_btree_block  *block)
 681 {
 682         int                     rval = 0;
 683         xfs_dfsbno_t            left = be64_to_cpu(block->bb_u.l.bb_leftsib);
 684         xfs_dfsbno_t            right = be64_to_cpu(block->bb_u.l.bb_rightsib);
 685
 686         if ((lr & XFS_BTCUR_LEFTRA) && left != NULLDFSBNO) {
 687                 xfs_btree_reada_bufl(cur->bc_mp, left, 1);
 688                 rval++;
 689         }
 690
 691         if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLDFSBNO) {
 692                 xfs_btree_reada_bufl(cur->bc_mp, right, 1);
 693                 rval++;
 694         }
 695
 696         return rval;
 697 }
 698
 699 STATIC int
 700 xfs_btree_readahead_sblock(
 701         struct xfs_btree_cur    *cur,
 702         int                     lr,
 703         struct xfs_btree_block *block)
 704 {
 705         int                     rval = 0;
 706         xfs_agblock_t           left = be32_to_cpu(block->bb_u.s.bb_leftsib);
 707         xfs_agblock_t           right = be32_to_cpu(block->bb_u.s.bb_rightsib);
 708
 709
 710         if ((lr & XFS_BTCUR_LEFTRA) && left != NULLAGBLOCK) {
 711                 xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
 712                                      left, 1);
 713                 rval++;
 714         }
 715
 716         if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {
 717                 xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
 718                                      right, 1);
 719                 rval++;
 720         }
 721
 722         return rval;
 723 }
 724
 725 /*
 726  * Read-ahead btree blocks, at the given level.
 727  * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
 728  */
 729 STATIC int
 730 xfs_btree_readahead(
 731         struct xfs_btree_cur    *cur,           /* btree cursor */
 732         int                     lev,            /* level in btree */
 733         int                     lr)             /* left/right bits */
 734 {
 735         struct xfs_btree_block  *block;
 736
 737         /*
 738          * No readahead needed if we are at the root level and the
 739          * btree root is stored in the inode.
 740          */
 741         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
 742             (lev == cur->bc_nlevels - 1))
 743                 return 0;
 744
 745         if ((cur->bc_ra[lev] | lr) == cur->bc_ra[lev])
 746                 return 0;
 747
 748         cur->bc_ra[lev] |= lr;
 749         block = XFS_BUF_TO_BLOCK(cur->bc_bufs[lev]);
 750
 751         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 752                 return xfs_btree_readahead_lblock(cur, lr, block);
 753         return xfs_btree_readahead_sblock(cur, lr, block);
 754 }
 755
 756 /*
 757  * Set the buffer for level "lev" in the cursor to bp, releasing
 758  * any previous buffer.
 759  */
 760 STATIC void
 761 xfs_btree_setbuf(
 762         xfs_btree_cur_t         *cur,   /* btree cursor */
 763         int                     lev,    /* level in btree */
 764         xfs_buf_t               *bp)    /* new buffer to set */
 765 {
 766         struct xfs_btree_block  *b;     /* btree block */
 767
 768         if (cur->bc_bufs[lev])
 769                 xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[lev]);
 770         cur->bc_bufs[lev] = bp;
 771         cur->bc_ra[lev] = 0;
 772
 773         b = XFS_BUF_TO_BLOCK(bp);
 774         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 775                 if (b->bb_u.l.bb_leftsib == cpu_to_be64(NULLDFSBNO))
 776                         cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
 777                 if (b->bb_u.l.bb_rightsib == cpu_to_be64(NULLDFSBNO))
 778                         cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
 779         } else {
 780                 if (b->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK))
 781                         cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
 782                 if (b->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK))
 783                         cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
 784         }
 785 }
 786
 787 STATIC int
 788 xfs_btree_ptr_is_null(
 789         struct xfs_btree_cur    *cur,
 790         union xfs_btree_ptr     *ptr)
 791 {
 792         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 793                 return ptr->l == cpu_to_be64(NULLDFSBNO);
 794         else
 795                 return ptr->s == cpu_to_be32(NULLAGBLOCK);
 796 }
 797
 798 STATIC void
 799 xfs_btree_set_ptr_null(
 800         struct xfs_btree_cur    *cur,
 801         union xfs_btree_ptr     *ptr)
 802 {
 803         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 804                 ptr->l = cpu_to_be64(NULLDFSBNO);
 805         else
 806                 ptr->s = cpu_to_be32(NULLAGBLOCK);
 807 }
 808
 809 /*
 810  * Get/set/init sibling pointers
 811  */
 812 STATIC void
 813 xfs_btree_get_sibling(
 814         struct xfs_btree_cur    *cur,
 815         struct xfs_btree_block  *block,
 816         union xfs_btree_ptr     *ptr,
 817         int                     lr)
 818 {
 819         ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
 820
 821         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 822                 if (lr == XFS_BB_RIGHTSIB)
 823                         ptr->l = block->bb_u.l.bb_rightsib;
 824                 else
 825                         ptr->l = block->bb_u.l.bb_leftsib;
 826         } else {
 827                 if (lr == XFS_BB_RIGHTSIB)
 828                         ptr->s = block->bb_u.s.bb_rightsib;
 829                 else
 830                         ptr->s = block->bb_u.s.bb_leftsib;
 831         }
 832 }
 833
 834 STATIC void
 835 xfs_btree_set_sibling(
 836         struct xfs_btree_cur    *cur,
 837         struct xfs_btree_block  *block,
 838         union xfs_btree_ptr     *ptr,
 839         int                     lr)
 840 {
 841         ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
 842
 843         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 844                 if (lr == XFS_BB_RIGHTSIB)
 845                         block->bb_u.l.bb_rightsib = ptr->l;
 846                 else
 847                         block->bb_u.l.bb_leftsib = ptr->l;
 848         } else {
 849                 if (lr == XFS_BB_RIGHTSIB)
 850                         block->bb_u.s.bb_rightsib = ptr->s;
 851                 else
 852                         block->bb_u.s.bb_leftsib = ptr->s;
 853         }
 854 }
 855
 856 STATIC void
 857 xfs_btree_init_block(
 858         struct xfs_btree_cur    *cur,
 859         int                     level,
 860         int                     numrecs,
 861         struct xfs_btree_block  *new)   /* new block */
 862 {
 863         new->bb_magic = cpu_to_be32(xfs_magics[cur->bc_btnum]);
 864         new->bb_level = cpu_to_be16(level);
 865         new->bb_numrecs = cpu_to_be16(numrecs);
 866
 867         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 868                 new->bb_u.l.bb_leftsib = cpu_to_be64(NULLDFSBNO);
 869                 new->bb_u.l.bb_rightsib = cpu_to_be64(NULLDFSBNO);
 870         } else {
 871                 new->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
 872                 new->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
 873         }
 874 }
 875
 876 /*
 877  * Return true if ptr is the last record in the btree and
 878  * we need to track updateѕ to this record.  The decision
 879  * will be further refined in the update_lastrec method.
 880  */
 881 STATIC int
 882 xfs_btree_is_lastrec(
 883         struct xfs_btree_cur    *cur,
 884         struct xfs_btree_block  *block,
 885         int                     level)
 886 {
 887         union xfs_btree_ptr     ptr;
 888
 889         if (level > 0)
 890                 return 0;
 891         if (!(cur->bc_flags & XFS_BTREE_LASTREC_UPDATE))
 892                 return 0;
 893
 894         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
 895         if (!xfs_btree_ptr_is_null(cur, &ptr))
 896                 return 0;
 897         return 1;
 898 }
 899
 900 STATIC void
 901 xfs_btree_buf_to_ptr(
 902         struct xfs_btree_cur    *cur,
 903         struct xfs_buf          *bp,
 904         union xfs_btree_ptr     *ptr)
 905 {
 906         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 907                 ptr->l = cpu_to_be64(XFS_DADDR_TO_FSB(cur->bc_mp,
 908                                         XFS_BUF_ADDR(bp)));
 909         else {
 910                 ptr->s = cpu_to_be32(xfs_daddr_to_agbno(cur->bc_mp,
 911                                         XFS_BUF_ADDR(bp)));
 912         }
 913 }
 914
 915 STATIC xfs_daddr_t
 916 xfs_btree_ptr_to_daddr(
 917         struct xfs_btree_cur    *cur,
 918         union xfs_btree_ptr     *ptr)
 919 {
 920         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 921                 ASSERT(ptr->l != cpu_to_be64(NULLDFSBNO));
 922
 923                 return XFS_FSB_TO_DADDR(cur->bc_mp, be64_to_cpu(ptr->l));
 924         } else {
 925                 ASSERT(cur->bc_private.a.agno != NULLAGNUMBER);
 926                 ASSERT(ptr->s != cpu_to_be32(NULLAGBLOCK));
 927
 928                 return XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_private.a.agno,
 929                                         be32_to_cpu(ptr->s));
 930         }
 931 }
 932
 933 STATIC void
 934 xfs_btree_set_refs(
 935         struct xfs_btree_cur    *cur,
 936         struct xfs_buf          *bp)
 937 {
 938         switch (cur->bc_btnum) {
 939         case XFS_BTNUM_BNO:
 940         case XFS_BTNUM_CNT:
 941                 xfs_buf_set_ref(bp, XFS_ALLOC_BTREE_REF);
 942                 break;
 943         case XFS_BTNUM_INO:
 944                 xfs_buf_set_ref(bp, XFS_INO_BTREE_REF);
 945                 break;
 946         case XFS_BTNUM_BMAP:
 947                 xfs_buf_set_ref(bp, XFS_BMAP_BTREE_REF);
 948                 break;
 949         default:
 950                 ASSERT(0);
 951         }
 952 }
 953
 954 STATIC int
 955 xfs_btree_get_buf_block(
 956         struct xfs_btree_cur    *cur,
 957         union xfs_btree_ptr     *ptr,
 958         int                     flags,
 959         struct xfs_btree_block  **block,
 960         struct xfs_buf          **bpp)
 961 {
 962         struct xfs_mount        *mp = cur->bc_mp;
 963         xfs_daddr_t             d;
 964
 965         /* need to sort out how callers deal with failures first */
 966         ASSERT(!(flags & XBF_TRYLOCK));
 967
 968         d = xfs_btree_ptr_to_daddr(cur, ptr);
 969         *bpp = xfs_trans_get_buf(cur->bc_tp, mp->m_ddev_targp, d,
 970                                  mp->m_bsize, flags);
 971
 972         if (!*bpp)
 973                 return ENOMEM;
 974
 975         *block = XFS_BUF_TO_BLOCK(*bpp);
 976         return 0;
 977 }
 978
 979 /*
 980  * Read in the buffer at the given ptr and return the buffer and
 981  * the block pointer within the buffer.
 982  */
 983 STATIC int
 984 xfs_btree_read_buf_block(
 985         struct xfs_btree_cur    *cur,
 986         union xfs_btree_ptr     *ptr,
 987         int                     level,
 988         int                     flags,
 989         struct xfs_btree_block  **block,
 990         struct xfs_buf          **bpp)
 991 {
 992         struct xfs_mount        *mp = cur->bc_mp;
 993         xfs_daddr_t             d;
 994         int                     error;
 995
 996         /* need to sort out how callers deal with failures first */
 997         ASSERT(!(flags & XBF_TRYLOCK));
 998
 999         d = xfs_btree_ptr_to_daddr(cur, ptr);
1000         error = xfs_trans_read_buf(mp, cur->bc_tp, mp->m_ddev_targp, d,
1001                                    mp->m_bsize, flags, bpp);
1002         if (error)
1003                 return error;
1004
1005         ASSERT(!xfs_buf_geterror(*bpp));
1006
1007         xfs_btree_set_refs(cur, *bpp);
1008         *block = XFS_BUF_TO_BLOCK(*bpp);
1009
1010         error = xfs_btree_check_block(cur, *block, level, *bpp);
1011         if (error)
1012                 xfs_trans_brelse(cur->bc_tp, *bpp);
1013         return error;
1014 }
1015
1016 /*
1017  * Copy keys from one btree block to another.
1018  */
1019 STATIC void
1020 xfs_btree_copy_keys(
1021         struct xfs_btree_cur    *cur,
1022         union xfs_btree_key     *dst_key,
1023         union xfs_btree_key     *src_key,
1024         int                     numkeys)
1025 {
1026         ASSERT(numkeys >= 0);
1027         memcpy(dst_key, src_key, numkeys * cur->bc_ops->key_len);
1028 }
1029
1030 /*
1031  * Copy records from one btree block to another.
1032  */
1033 STATIC void
1034 xfs_btree_copy_recs(
1035         struct xfs_btree_cur    *cur,
1036         union xfs_btree_rec     *dst_rec,
1037         union xfs_btree_rec     *src_rec,
1038         int                     numrecs)
1039 {
1040         ASSERT(numrecs >= 0);
1041         memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
1042 }
1043
1044 /*
1045  * Copy block pointers from one btree block to another.
1046  */
1047 STATIC void
1048 xfs_btree_copy_ptrs(
1049         struct xfs_btree_cur    *cur,
1050         union xfs_btree_ptr     *dst_ptr,
1051         union xfs_btree_ptr     *src_ptr,
1052         int                     numptrs)
1053 {
1054         ASSERT(numptrs >= 0);
1055         memcpy(dst_ptr, src_ptr, numptrs * xfs_btree_ptr_len(cur));
1056 }
1057
1058 /*
1059  * Shift keys one index left/right inside a single btree block.
1060  */
1061 STATIC void
1062 xfs_btree_shift_keys(
1063         struct xfs_btree_cur    *cur,
1064         union xfs_btree_key     *key,
1065         int                     dir,
1066         int                     numkeys)
1067 {
1068         char                    *dst_key;
1069
1070         ASSERT(numkeys >= 0);
1071         ASSERT(dir == 1 || dir == -1);
1072
1073         dst_key = (char *)key + (dir * cur->bc_ops->key_len);
1074         memmove(dst_key, key, numkeys * cur->bc_ops->key_len);
1075 }
1076
1077 /*
1078  * Shift records one index left/right inside a single btree block.
1079  */
1080 STATIC void
1081 xfs_btree_shift_recs(
1082         struct xfs_btree_cur    *cur,
1083         union xfs_btree_rec     *rec,
1084         int                     dir,
1085         int                     numrecs)
1086 {
1087         char                    *dst_rec;
1088
1089         ASSERT(numrecs >= 0);
1090         ASSERT(dir == 1 || dir == -1);
1091
1092         dst_rec = (char *)rec + (dir * cur->bc_ops->rec_len);
1093         memmove(dst_rec, rec, numrecs * cur->bc_ops->rec_len);
1094 }
1095
1096 /*
1097  * Shift block pointers one index left/right inside a single btree block.
1098  */
1099 STATIC void
1100 xfs_btree_shift_ptrs(
1101         struct xfs_btree_cur    *cur,
1102         union xfs_btree_ptr     *ptr,
1103         int                     dir,
1104         int                     numptrs)
1105 {
1106         char                    *dst_ptr;
1107
1108         ASSERT(numptrs >= 0);
1109         ASSERT(dir == 1 || dir == -1);
1110
1111         dst_ptr = (char *)ptr + (dir * xfs_btree_ptr_len(cur));
1112         memmove(dst_ptr, ptr, numptrs * xfs_btree_ptr_len(cur));
1113 }
1114
1115 /*
1116  * Log key values from the btree block.
1117  */
1118 STATIC void
1119 xfs_btree_log_keys(
1120         struct xfs_btree_cur    *cur,
1121         struct xfs_buf          *bp,
1122         int                     first,
1123         int                     last)
1124 {
1125         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1126         XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
1127
1128         if (bp) {
1129                 xfs_trans_log_buf(cur->bc_tp, bp,
1130                                   xfs_btree_key_offset(cur, first),
1131                                   xfs_btree_key_offset(cur, last + 1) - 1);
1132         } else {
1133                 xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1134                                 xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1135         }
1136
1137         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1138 }
1139
1140 /*
1141  * Log record values from the btree block.
1142  */
1143 void
1144 xfs_btree_log_recs(
1145         struct xfs_btree_cur    *cur,
1146         struct xfs_buf          *bp,
1147         int                     first,
1148         int                     last)
1149 {
1150         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1151         XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
1152
1153         xfs_trans_log_buf(cur->bc_tp, bp,
1154                           xfs_btree_rec_offset(cur, first),
1155                           xfs_btree_rec_offset(cur, last + 1) - 1);
1156
1157         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1158 }
1159
1160 /*
1161  * Log block pointer fields from a btree block (nonleaf).
1162  */
1163 STATIC void
1164 xfs_btree_log_ptrs(
1165         struct xfs_btree_cur    *cur,   /* btree cursor */
1166         struct xfs_buf          *bp,    /* buffer containing btree block */
1167         int                     first,  /* index of first pointer to log */
1168         int                     last)   /* index of last pointer to log */
1169 {
1170         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1171         XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
1172
1173         if (bp) {
1174                 struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
1175                 int                     level = xfs_btree_get_level(block);
1176
1177                 xfs_trans_log_buf(cur->bc_tp, bp,
1178                                 xfs_btree_ptr_offset(cur, first, level),
1179                                 xfs_btree_ptr_offset(cur, last + 1, level) - 1);
1180         } else {
1181                 xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1182                         xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1183         }
1184
1185         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1186 }
1187
1188 /*
1189  * Log fields from a btree block header.
1190  */
1191 void
1192 xfs_btree_log_block(
1193         struct xfs_btree_cur    *cur,   /* btree cursor */
1194         struct xfs_buf          *bp,    /* buffer containing btree block */
1195         int                     fields) /* mask of fields: XFS_BB_... */
1196 {
1197         int                     first;  /* first byte offset logged */
1198         int                     last;   /* last byte offset logged */
1199         static const short      soffsets[] = {  /* table of offsets (short) */
1200                 offsetof(struct xfs_btree_block, bb_magic),
1201                 offsetof(struct xfs_btree_block, bb_level),
1202                 offsetof(struct xfs_btree_block, bb_numrecs),
1203                 offsetof(struct xfs_btree_block, bb_u.s.bb_leftsib),
1204                 offsetof(struct xfs_btree_block, bb_u.s.bb_rightsib),
1205                 XFS_BTREE_SBLOCK_LEN
1206         };
1207         static const short      loffsets[] = {  /* table of offsets (long) */
1208                 offsetof(struct xfs_btree_block, bb_magic),
1209                 offsetof(struct xfs_btree_block, bb_level),
1210                 offsetof(struct xfs_btree_block, bb_numrecs),
1211                 offsetof(struct xfs_btree_block, bb_u.l.bb_leftsib),
1212                 offsetof(struct xfs_btree_block, bb_u.l.bb_rightsib),
1213                 XFS_BTREE_LBLOCK_LEN
1214         };
1215
1216         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1217         XFS_BTREE_TRACE_ARGBI(cur, bp, fields);
1218
1219         if (bp) {
1220                 xfs_btree_offsets(fields,
1221                                   (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
1222                                         loffsets : soffsets,
1223                                   XFS_BB_NUM_BITS, &first, &last);
1224                 xfs_trans_log_buf(cur->bc_tp, bp, first, last);
1225         } else {
1226                 xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1227                         xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1228         }
1229
1230         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1231 }
1232
1233 /*
1234  * Increment cursor by one record at the level.
1235  * For nonzero levels the leaf-ward information is untouched.
1236  */
1237 int                                             /* error */
1238 xfs_btree_increment(
1239         struct xfs_btree_cur    *cur,
1240         int                     level,
1241         int                     *stat)          /* success/failure */
1242 {
1243         struct xfs_btree_block  *block;
1244         union xfs_btree_ptr     ptr;
1245         struct xfs_buf          *bp;
1246         int                     error;          /* error return value */
1247         int                     lev;
1248
1249         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1250         XFS_BTREE_TRACE_ARGI(cur, level);
1251
1252         ASSERT(level < cur->bc_nlevels);
1253
1254         /* Read-ahead to the right at this level. */
1255         xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
1256
1257         /* Get a pointer to the btree block. */
1258         block = xfs_btree_get_block(cur, level, &bp);
1259
1260 #ifdef DEBUG
1261         error = xfs_btree_check_block(cur, block, level, bp);
1262         if (error)
1263                 goto error0;
1264 #endif
1265
1266         /* We're done if we remain in the block after the increment. */
1267         if (++cur->bc_ptrs[level] <= xfs_btree_get_numrecs(block))
1268                 goto out1;
1269
1270         /* Fail if we just went off the right edge of the tree. */
1271         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1272         if (xfs_btree_ptr_is_null(cur, &ptr))
1273                 goto out0;
1274
1275         XFS_BTREE_STATS_INC(cur, increment);
1276
1277         /*
1278          * March up the tree incrementing pointers.
1279          * Stop when we don't go off the right edge of a block.
1280          */
1281         for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1282                 block = xfs_btree_get_block(cur, lev, &bp);
1283
1284 #ifdef DEBUG
1285                 error = xfs_btree_check_block(cur, block, lev, bp);
1286                 if (error)
1287                         goto error0;
1288 #endif
1289
1290                 if (++cur->bc_ptrs[lev] <= xfs_btree_get_numrecs(block))
1291                         break;
1292
1293                 /* Read-ahead the right block for the next loop. */
1294                 xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);
1295         }
1296
1297         /*
1298          * If we went off the root then we are either seriously
1299          * confused or have the tree root in an inode.
1300          */
1301         if (lev == cur->bc_nlevels) {
1302                 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1303                         goto out0;
1304                 ASSERT(0);
1305                 error = EFSCORRUPTED;
1306                 goto error0;
1307         }
1308         ASSERT(lev < cur->bc_nlevels);
1309
1310         /*
1311          * Now walk back down the tree, fixing up the cursor's buffer
1312          * pointers and key numbers.
1313          */
1314         for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1315                 union xfs_btree_ptr     *ptrp;
1316
1317                 ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
1318                 error = xfs_btree_read_buf_block(cur, ptrp, --lev,
1319                                                         0, &block, &bp);
1320                 if (error)
1321                         goto error0;
1322
1323                 xfs_btree_setbuf(cur, lev, bp);
1324                 cur->bc_ptrs[lev] = 1;
1325         }
1326 out1:
1327         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1328         *stat = 1;
1329         return 0;
1330
1331 out0:
1332         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1333         *stat = 0;
1334         return 0;
1335
1336 error0:
1337         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1338         return error;
1339 }
1340
1341 /*
1342  * Decrement cursor by one record at the level.
1343  * For nonzero levels the leaf-ward information is untouched.
1344  */
1345 int                                             /* error */
1346 xfs_btree_decrement(
1347         struct xfs_btree_cur    *cur,
1348         int                     level,
1349         int                     *stat)          /* success/failure */
1350 {
1351         struct xfs_btree_block  *block;
1352         xfs_buf_t               *bp;
1353         int                     error;          /* error return value */
1354         int                     lev;
1355         union xfs_btree_ptr     ptr;
1356
1357         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1358         XFS_BTREE_TRACE_ARGI(cur, level);
1359
1360         ASSERT(level < cur->bc_nlevels);
1361
1362         /* Read-ahead to the left at this level. */
1363         xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);
1364
1365         /* We're done if we remain in the block after the decrement. */
1366         if (--cur->bc_ptrs[level] > 0)
1367                 goto out1;
1368
1369         /* Get a pointer to the btree block. */
1370         block = xfs_btree_get_block(cur, level, &bp);
1371
1372 #ifdef DEBUG
1373         error = xfs_btree_check_block(cur, block, level, bp);
1374         if (error)
1375                 goto error0;
1376 #endif
1377
1378         /* Fail if we just went off the left edge of the tree. */
1379         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
1380         if (xfs_btree_ptr_is_null(cur, &ptr))
1381                 goto out0;
1382
1383         XFS_BTREE_STATS_INC(cur, decrement);
1384
1385         /*
1386          * March up the tree decrementing pointers.
1387          * Stop when we don't go off the left edge of a block.
1388          */
1389         for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1390                 if (--cur->bc_ptrs[lev] > 0)
1391                         break;
1392                 /* Read-ahead the left block for the next loop. */
1393                 xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);
1394         }
1395
1396         /*
1397          * If we went off the root then we are seriously confused.
1398          * or the root of the tree is in an inode.
1399          */
1400         if (lev == cur->bc_nlevels) {
1401                 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1402                         goto out0;
1403                 ASSERT(0);
1404                 error = EFSCORRUPTED;
1405                 goto error0;
1406         }
1407         ASSERT(lev < cur->bc_nlevels);
1408
1409         /*
1410          * Now walk back down the tree, fixing up the cursor's buffer
1411          * pointers and key numbers.
1412          */
1413         for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1414                 union xfs_btree_ptr     *ptrp;
1415
1416                 ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
1417                 error = xfs_btree_read_buf_block(cur, ptrp, --lev,
1418                                                         0, &block, &bp);
1419                 if (error)
1420                         goto error0;
1421                 xfs_btree_setbuf(cur, lev, bp);
1422                 cur->bc_ptrs[lev] = xfs_btree_get_numrecs(block);
1423         }
1424 out1:
1425         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1426         *stat = 1;
1427         return 0;
1428
1429 out0:
1430         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1431         *stat = 0;
1432         return 0;
1433
1434 error0:
1435         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1436         return error;
1437 }
1438
1439 STATIC int
1440 xfs_btree_lookup_get_block(
1441         struct xfs_btree_cur    *cur,   /* btree cursor */
1442         int                     level,  /* level in the btree */
1443         union xfs_btree_ptr     *pp,    /* ptr to btree block */
1444         struct xfs_btree_block  **blkp) /* return btree block */
1445 {
1446         struct xfs_buf          *bp;    /* buffer pointer for btree block */
1447         int                     error = 0;
1448
1449         /* special case the root block if in an inode */
1450         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1451             (level == cur->bc_nlevels - 1)) {
1452                 *blkp = xfs_btree_get_iroot(cur);
1453                 return 0;
1454         }
1455
1456         /*
1457          * If the old buffer at this level for the disk address we are
1458          * looking for re-use it.
1459          *
1460          * Otherwise throw it away and get a new one.
1461          */
1462         bp = cur->bc_bufs[level];
1463         if (bp && XFS_BUF_ADDR(bp) == xfs_btree_ptr_to_daddr(cur, pp)) {
1464                 *blkp = XFS_BUF_TO_BLOCK(bp);
1465                 return 0;
1466         }
1467
1468         error = xfs_btree_read_buf_block(cur, pp, level, 0, blkp, &bp);
1469         if (error)
1470                 return error;
1471
1472         xfs_btree_setbuf(cur, level, bp);
1473         return 0;
1474 }
1475
1476 /*
1477  * Get current search key.  For level 0 we don't actually have a key
1478  * structure so we make one up from the record.  For all other levels
1479  * we just return the right key.
1480  */
1481 STATIC union xfs_btree_key *
1482 xfs_lookup_get_search_key(
1483         struct xfs_btree_cur    *cur,
1484         int                     level,
1485         int                     keyno,
1486         struct xfs_btree_block  *block,
1487         union xfs_btree_key     *kp)
1488 {
1489         if (level == 0) {
1490                 cur->bc_ops->init_key_from_rec(kp,
1491                                 xfs_btree_rec_addr(cur, keyno, block));
1492                 return kp;
1493         }
1494
1495         return xfs_btree_key_addr(cur, keyno, block);
1496 }
1497
1498 /*
1499  * Lookup the record.  The cursor is made to point to it, based on dir.
1500  * Return 0 if can't find any such record, 1 for success.
1501  */
1502 int                                     /* error */
1503 xfs_btree_lookup(
1504         struct xfs_btree_cur    *cur,   /* btree cursor */
1505         xfs_lookup_t            dir,    /* <=, ==, or >= */
1506         int                     *stat)  /* success/failure */
1507 {
1508         struct xfs_btree_block  *block; /* current btree block */
1509         __int64_t               diff;   /* difference for the current key */
1510         int                     error;  /* error return value */
1511         int                     keyno;  /* current key number */
1512         int                     level;  /* level in the btree */
1513         union xfs_btree_ptr     *pp;    /* ptr to btree block */
1514         union xfs_btree_ptr     ptr;    /* ptr to btree block */
1515
1516         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1517         XFS_BTREE_TRACE_ARGI(cur, dir);
1518
1519         XFS_BTREE_STATS_INC(cur, lookup);
1520
1521         block = NULL;
1522         keyno = 0;
1523
1524         /* initialise start pointer from cursor */
1525         cur->bc_ops->init_ptr_from_cur(cur, &ptr);
1526         pp = &ptr;
1527
1528         /*
1529          * Iterate over each level in the btree, starting at the root.
1530          * For each level above the leaves, find the key we need, based
1531          * on the lookup record, then follow the corresponding block
1532          * pointer down to the next level.
1533          */
1534         for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {
1535                 /* Get the block we need to do the lookup on. */
1536                 error = xfs_btree_lookup_get_block(cur, level, pp, &block);
1537                 if (error)
1538                         goto error0;
1539
1540                 if (diff == 0) {
1541                         /*
1542                          * If we already had a key match at a higher level, we
1543                          * know we need to use the first entry in this block.
1544                          */
1545                         keyno = 1;
1546                 } else {
1547                         /* Otherwise search this block. Do a binary search. */
1548
1549                         int     high;   /* high entry number */
1550                         int     low;    /* low entry number */
1551
1552                         /* Set low and high entry numbers, 1-based. */
1553                         low = 1;
1554                         high = xfs_btree_get_numrecs(block);
1555                         if (!high) {
1556                                 /* Block is empty, must be an empty leaf. */
1557                                 ASSERT(level == 0 && cur->bc_nlevels == 1);
1558
1559                                 cur->bc_ptrs[0] = dir != XFS_LOOKUP_LE;
1560                                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1561                                 *stat = 0;
1562                                 return 0;
1563                         }
1564
1565                         /* Binary search the block. */
1566                         while (low <= high) {
1567                                 union xfs_btree_key     key;
1568                                 union xfs_btree_key     *kp;
1569
1570                                 XFS_BTREE_STATS_INC(cur, compare);
1571
1572                                 /* keyno is average of low and high. */
1573                                 keyno = (low + high) >> 1;
1574
1575                                 /* Get current search key */
1576                                 kp = xfs_lookup_get_search_key(cur, level,
1577                                                 keyno, block, &key);
1578
1579                                 /*
1580                                  * Compute difference to get next direction:
1581                                  *  - less than, move right
1582                                  *  - greater than, move left
1583                                  *  - equal, we're done
1584                                  */
1585                                 diff = cur->bc_ops->key_diff(cur, kp);
1586                                 if (diff < 0)
1587                                         low = keyno + 1;
1588                                 else if (diff > 0)
1589                                         high = keyno - 1;
1590                                 else
1591                                         break;
1592                         }
1593                 }
1594
1595                 /*
1596                  * If there are more levels, set up for the next level
1597                  * by getting the block number and filling in the cursor.
1598                  */
1599                 if (level > 0) {
1600                         /*
1601                          * If we moved left, need the previous key number,
1602                          * unless there isn't one.
1603                          */
1604                         if (diff > 0 && --keyno < 1)
1605                                 keyno = 1;
1606                         pp = xfs_btree_ptr_addr(cur, keyno, block);
1607
1608 #ifdef DEBUG
1609                         error = xfs_btree_check_ptr(cur, pp, 0, level);
1610                         if (error)
1611                                 goto error0;
1612 #endif
1613                         cur->bc_ptrs[level] = keyno;
1614                 }
1615         }
1616
1617         /* Done with the search. See if we need to adjust the results. */
1618         if (dir != XFS_LOOKUP_LE && diff < 0) {
1619                 keyno++;
1620                 /*
1621                  * If ge search and we went off the end of the block, but it's
1622                  * not the last block, we're in the wrong block.
1623                  */
1624                 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1625                 if (dir == XFS_LOOKUP_GE &&
1626                     keyno > xfs_btree_get_numrecs(block) &&
1627                     !xfs_btree_ptr_is_null(cur, &ptr)) {
1628                         int     i;
1629
1630                         cur->bc_ptrs[0] = keyno;
1631                         error = xfs_btree_increment(cur, 0, &i);
1632                         if (error)
1633                                 goto error0;
1634                         XFS_WANT_CORRUPTED_RETURN(i == 1);
1635                         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1636                         *stat = 1;
1637                         return 0;
1638                 }
1639         } else if (dir == XFS_LOOKUP_LE && diff > 0)
1640                 keyno--;
1641         cur->bc_ptrs[0] = keyno;
1642
1643         /* Return if we succeeded or not. */
1644         if (keyno == 0 || keyno > xfs_btree_get_numrecs(block))
1645                 *stat = 0;
1646         else if (dir != XFS_LOOKUP_EQ || diff == 0)
1647                 *stat = 1;
1648         else
1649                 *stat = 0;
1650         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1651         return 0;
1652
1653 error0:
1654         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1655         return error;
1656 }
1657
1658 /*
1659  * Update keys at all levels from here to the root along the cursor's path.
1660  */
1661 STATIC int
1662 xfs_btree_updkey(
1663         struct xfs_btree_cur    *cur,
1664         union xfs_btree_key     *keyp,
1665         int                     level)
1666 {
1667         struct xfs_btree_block  *block;
1668         struct xfs_buf          *bp;
1669         union xfs_btree_key     *kp;
1670         int                     ptr;
1671
1672         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1673         XFS_BTREE_TRACE_ARGIK(cur, level, keyp);
1674
1675         ASSERT(!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) || level >= 1);
1676
1677         /*
1678          * Go up the tree from this level toward the root.
1679          * At each level, update the key value to the value input.
1680          * Stop when we reach a level where the cursor isn't pointing
1681          * at the first entry in the block.
1682          */
1683         for (ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
1684 #ifdef DEBUG
1685                 int             error;
1686 #endif
1687                 block = xfs_btree_get_block(cur, level, &bp);
1688 #ifdef DEBUG
1689                 error = xfs_btree_check_block(cur, block, level, bp);
1690                 if (error) {
1691                         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1692                         return error;
1693                 }
1694 #endif
1695                 ptr = cur->bc_ptrs[level];
1696                 kp = xfs_btree_key_addr(cur, ptr, block);
1697                 xfs_btree_copy_keys(cur, kp, keyp, 1);
1698                 xfs_btree_log_keys(cur, bp, ptr, ptr);
1699         }
1700
1701         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1702         return 0;
1703 }
1704
1705 /*
1706  * Update the record referred to by cur to the value in the
1707  * given record. This either works (return 0) or gets an
1708  * EFSCORRUPTED error.
1709  */
1710 int
1711 xfs_btree_update(
1712         struct xfs_btree_cur    *cur,
1713         union xfs_btree_rec     *rec)
1714 {
1715         struct xfs_btree_block  *block;
1716         struct xfs_buf          *bp;
1717         int                     error;
1718         int                     ptr;
1719         union xfs_btree_rec     *rp;
1720
1721         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1722         XFS_BTREE_TRACE_ARGR(cur, rec);
1723
1724         /* Pick up the current block. */
1725         block = xfs_btree_get_block(cur, 0, &bp);
1726
1727 #ifdef DEBUG
1728         error = xfs_btree_check_block(cur, block, 0, bp);
1729         if (error)
1730                 goto error0;
1731 #endif
1732         /* Get the address of the rec to be updated. */
1733         ptr = cur->bc_ptrs[0];
1734         rp = xfs_btree_rec_addr(cur, ptr, block);
1735
1736         /* Fill in the new contents and log them. */
1737         xfs_btree_copy_recs(cur, rp, rec, 1);
1738         xfs_btree_log_recs(cur, bp, ptr, ptr);
1739
1740         /*
1741          * If we are tracking the last record in the tree and
1742          * we are at the far right edge of the tree, update it.
1743          */
1744         if (xfs_btree_is_lastrec(cur, block, 0)) {
1745                 cur->bc_ops->update_lastrec(cur, block, rec,
1746                                             ptr, LASTREC_UPDATE);
1747         }
1748
1749         /* Updating first rec in leaf. Pass new key value up to our parent. */
1750         if (ptr == 1) {
1751                 union xfs_btree_key     key;
1752
1753                 cur->bc_ops->init_key_from_rec(&key, rec);
1754                 error = xfs_btree_updkey(cur, &key, 1);
1755                 if (error)
1756                         goto error0;
1757         }
1758
1759         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1760         return 0;
1761
1762 error0:
1763         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1764         return error;
1765 }
1766
1767 /*
1768  * Move 1 record left from cur/level if possible.
1769  * Update cur to reflect the new path.
1770  */
1771 STATIC int                                      /* error */
1772 xfs_btree_lshift(
1773         struct xfs_btree_cur    *cur,
1774         int                     level,
1775         int                     *stat)          /* success/failure */
1776 {
1777         union xfs_btree_key     key;            /* btree key */
1778         struct xfs_buf          *lbp;           /* left buffer pointer */
1779         struct xfs_btree_block  *left;          /* left btree block */
1780         int                     lrecs;          /* left record count */
1781         struct xfs_buf          *rbp;           /* right buffer pointer */
1782         struct xfs_btree_block  *right;         /* right btree block */
1783         int                     rrecs;          /* right record count */
1784         union xfs_btree_ptr     lptr;           /* left btree pointer */
1785         union xfs_btree_key     *rkp = NULL;    /* right btree key */
1786         union xfs_btree_ptr     *rpp = NULL;    /* right address pointer */
1787         union xfs_btree_rec     *rrp = NULL;    /* right record pointer */
1788         int                     error;          /* error return value */
1789
1790         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1791         XFS_BTREE_TRACE_ARGI(cur, level);
1792
1793         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1794             level == cur->bc_nlevels - 1)
1795                 goto out0;
1796
1797         /* Set up variables for this block as "right". */
1798         right = xfs_btree_get_block(cur, level, &rbp);
1799
1800 #ifdef DEBUG
1801         error = xfs_btree_check_block(cur, right, level, rbp);
1802         if (error)
1803                 goto error0;
1804 #endif
1805
1806         /* If we've got no left sibling then we can't shift an entry left. */
1807         xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
1808         if (xfs_btree_ptr_is_null(cur, &lptr))
1809                 goto out0;
1810
1811         /*
1812          * If the cursor entry is the one that would be moved, don't
1813          * do it... it's too complicated.
1814          */
1815         if (cur->bc_ptrs[level] <= 1)
1816                 goto out0;
1817
1818         /* Set up the left neighbor as "left". */
1819         error = xfs_btree_read_buf_block(cur, &lptr, level, 0, &left, &lbp);
1820         if (error)
1821                 goto error0;
1822
1823         /* If it's full, it can't take another entry. */
1824         lrecs = xfs_btree_get_numrecs(left);
1825         if (lrecs == cur->bc_ops->get_maxrecs(cur, level))
1826                 goto out0;
1827
1828         rrecs = xfs_btree_get_numrecs(right);
1829
1830         /*
1831          * We add one entry to the left side and remove one for the right side.
1832          * Account for it here, the changes will be updated on disk and logged
1833          * later.
1834          */
1835         lrecs++;
1836         rrecs--;
1837
1838         XFS_BTREE_STATS_INC(cur, lshift);
1839         XFS_BTREE_STATS_ADD(cur, moves, 1);
1840
1841         /*
1842          * If non-leaf, copy a key and a ptr to the left block.
1843          * Log the changes to the left block.
1844          */
1845         if (level > 0) {
1846                 /* It's a non-leaf.  Move keys and pointers. */
1847                 union xfs_btree_key     *lkp;   /* left btree key */
1848                 union xfs_btree_ptr     *lpp;   /* left address pointer */
1849
1850                 lkp = xfs_btree_key_addr(cur, lrecs, left);
1851                 rkp = xfs_btree_key_addr(cur, 1, right);
1852
1853                 lpp = xfs_btree_ptr_addr(cur, lrecs, left);
1854                 rpp = xfs_btree_ptr_addr(cur, 1, right);
1855 #ifdef DEBUG
1856                 error = xfs_btree_check_ptr(cur, rpp, 0, level);
1857                 if (error)
1858                         goto error0;
1859 #endif
1860                 xfs_btree_copy_keys(cur, lkp, rkp, 1);
1861                 xfs_btree_copy_ptrs(cur, lpp, rpp, 1);
1862
1863                 xfs_btree_log_keys(cur, lbp, lrecs, lrecs);
1864                 xfs_btree_log_ptrs(cur, lbp, lrecs, lrecs);
1865
1866                 ASSERT(cur->bc_ops->keys_inorder(cur,
1867                         xfs_btree_key_addr(cur, lrecs - 1, left), lkp));
1868         } else {
1869                 /* It's a leaf.  Move records.  */
1870                 union xfs_btree_rec     *lrp;   /* left record pointer */
1871
1872                 lrp = xfs_btree_rec_addr(cur, lrecs, left);
1873                 rrp = xfs_btree_rec_addr(cur, 1, right);
1874
1875                 xfs_btree_copy_recs(cur, lrp, rrp, 1);
1876                 xfs_btree_log_recs(cur, lbp, lrecs, lrecs);
1877
1878                 ASSERT(cur->bc_ops->recs_inorder(cur,
1879                         xfs_btree_rec_addr(cur, lrecs - 1, left), lrp));
1880         }
1881
1882         xfs_btree_set_numrecs(left, lrecs);
1883         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
1884
1885         xfs_btree_set_numrecs(right, rrecs);
1886         xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
1887
1888         /*
1889          * Slide the contents of right down one entry.
1890          */
1891         XFS_BTREE_STATS_ADD(cur, moves, rrecs - 1);
1892         if (level > 0) {
1893                 /* It's a nonleaf. operate on keys and ptrs */
1894 #ifdef DEBUG
1895                 int                     i;              /* loop index */
1896
1897                 for (i = 0; i < rrecs; i++) {
1898                         error = xfs_btree_check_ptr(cur, rpp, i + 1, level);
1899                         if (error)
1900                                 goto error0;
1901                 }
1902 #endif
1903                 xfs_btree_shift_keys(cur,
1904                                 xfs_btree_key_addr(cur, 2, right),
1905                                 -1, rrecs);
1906                 xfs_btree_shift_ptrs(cur,
1907                                 xfs_btree_ptr_addr(cur, 2, right),
1908                                 -1, rrecs);
1909
1910                 xfs_btree_log_keys(cur, rbp, 1, rrecs);
1911                 xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
1912         } else {
1913                 /* It's a leaf. operate on records */
1914                 xfs_btree_shift_recs(cur,
1915                         xfs_btree_rec_addr(cur, 2, right),
1916                         -1, rrecs);
1917                 xfs_btree_log_recs(cur, rbp, 1, rrecs);
1918
1919                 /*
1920                  * If it's the first record in the block, we'll need a key
1921                  * structure to pass up to the next level (updkey).
1922                  */
1923                 cur->bc_ops->init_key_from_rec(&key,
1924                         xfs_btree_rec_addr(cur, 1, right));
1925                 rkp = &key;
1926         }
1927
1928         /* Update the parent key values of right. */
1929         error = xfs_btree_updkey(cur, rkp, level + 1);
1930         if (error)
1931                 goto error0;
1932
1933         /* Slide the cursor value left one. */
1934         cur->bc_ptrs[level]--;
1935
1936         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1937         *stat = 1;
1938         return 0;
1939
1940 out0:
1941         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1942         *stat = 0;
1943         return 0;
1944
1945 error0:
1946         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1947         return error;
1948 }
1949
1950 /*
1951  * Move 1 record right from cur/level if possible.
1952  * Update cur to reflect the new path.
1953  */
1954 STATIC int                                      /* error */
1955 xfs_btree_rshift(
1956         struct xfs_btree_cur    *cur,
1957         int                     level,
1958         int                     *stat)          /* success/failure */
1959 {
1960         union xfs_btree_key     key;            /* btree key */
1961         struct xfs_buf          *lbp;           /* left buffer pointer */
1962         struct xfs_btree_block  *left;          /* left btree block */
1963         struct xfs_buf          *rbp;           /* right buffer pointer */
1964         struct xfs_btree_block  *right;         /* right btree block */
1965         struct xfs_btree_cur    *tcur;          /* temporary btree cursor */
1966         union xfs_btree_ptr     rptr;           /* right block pointer */
1967         union xfs_btree_key     *rkp;           /* right btree key */
1968         int                     rrecs;          /* right record count */
1969         int                     lrecs;          /* left record count */
1970         int                     error;          /* error return value */
1971         int                     i;              /* loop counter */
1972
1973         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1974         XFS_BTREE_TRACE_ARGI(cur, level);
1975
1976         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1977             (level == cur->bc_nlevels - 1))
1978                 goto out0;
1979
1980         /* Set up variables for this block as "left". */
1981         left = xfs_btree_get_block(cur, level, &lbp);
1982
1983 #ifdef DEBUG
1984         error = xfs_btree_check_block(cur, left, level, lbp);
1985         if (error)
1986                 goto error0;
1987 #endif
1988
1989         /* If we've got no right sibling then we can't shift an entry right. */
1990         xfs_btree_get_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
1991         if (xfs_btree_ptr_is_null(cur, &rptr))
1992                 goto out0;
1993
1994         /*
1995          * If the cursor entry is the one that would be moved, don't
1996          * do it... it's too complicated.
1997          */
1998         lrecs = xfs_btree_get_numrecs(left);
1999         if (cur->bc_ptrs[level] >= lrecs)
2000                 goto out0;
2001
2002         /* Set up the right neighbor as "right". */
2003         error = xfs_btree_read_buf_block(cur, &rptr, level, 0, &right, &rbp);
2004         if (error)
2005                 goto error0;
2006
2007         /* If it's full, it can't take another entry. */
2008         rrecs = xfs_btree_get_numrecs(right);
2009         if (rrecs == cur->bc_ops->get_maxrecs(cur, level))
2010                 goto out0;
2011
2012         XFS_BTREE_STATS_INC(cur, rshift);
2013         XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2014
2015         /*
2016          * Make a hole at the start of the right neighbor block, then
2017          * copy the last left block entry to the hole.
2018          */
2019         if (level > 0) {
2020                 /* It's a nonleaf. make a hole in the keys and ptrs */
2021                 union xfs_btree_key     *lkp;
2022                 union xfs_btree_ptr     *lpp;
2023                 union xfs_btree_ptr     *rpp;
2024
2025                 lkp = xfs_btree_key_addr(cur, lrecs, left);
2026                 lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2027                 rkp = xfs_btree_key_addr(cur, 1, right);
2028                 rpp = xfs_btree_ptr_addr(cur, 1, right);
2029
2030 #ifdef DEBUG
2031                 for (i = rrecs - 1; i >= 0; i--) {
2032                         error = xfs_btree_check_ptr(cur, rpp, i, level);
2033                         if (error)
2034                                 goto error0;
2035                 }
2036 #endif
2037
2038                 xfs_btree_shift_keys(cur, rkp, 1, rrecs);
2039                 xfs_btree_shift_ptrs(cur, rpp, 1, rrecs);
2040
2041 #ifdef DEBUG
2042                 error = xfs_btree_check_ptr(cur, lpp, 0, level);
2043                 if (error)
2044                         goto error0;
2045 #endif
2046
2047                 /* Now put the new data in, and log it. */
2048                 xfs_btree_copy_keys(cur, rkp, lkp, 1);
2049                 xfs_btree_copy_ptrs(cur, rpp, lpp, 1);
2050
2051                 xfs_btree_log_keys(cur, rbp, 1, rrecs + 1);
2052                 xfs_btree_log_ptrs(cur, rbp, 1, rrecs + 1);
2053
2054                 ASSERT(cur->bc_ops->keys_inorder(cur, rkp,
2055                         xfs_btree_key_addr(cur, 2, right)));
2056         } else {
2057                 /* It's a leaf. make a hole in the records */
2058                 union xfs_btree_rec     *lrp;
2059                 union xfs_btree_rec     *rrp;
2060
2061                 lrp = xfs_btree_rec_addr(cur, lrecs, left);
2062                 rrp = xfs_btree_rec_addr(cur, 1, right);
2063
2064                 xfs_btree_shift_recs(cur, rrp, 1, rrecs);
2065
2066                 /* Now put the new data in, and log it. */
2067                 xfs_btree_copy_recs(cur, rrp, lrp, 1);
2068                 xfs_btree_log_recs(cur, rbp, 1, rrecs + 1);
2069
2070                 cur->bc_ops->init_key_from_rec(&key, rrp);
2071                 rkp = &key;
2072
2073                 ASSERT(cur->bc_ops->recs_inorder(cur, rrp,
2074                         xfs_btree_rec_addr(cur, 2, right)));
2075         }
2076
2077         /*
2078          * Decrement and log left's numrecs, bump and log right's numrecs.
2079          */
2080         xfs_btree_set_numrecs(left, --lrecs);
2081         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2082
2083         xfs_btree_set_numrecs(right, ++rrecs);
2084         xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2085
2086         /*
2087          * Using a temporary cursor, update the parent key values of the
2088          * block on the right.
2089          */
2090         error = xfs_btree_dup_cursor(cur, &tcur);
2091         if (error)
2092                 goto error0;
2093         i = xfs_btree_lastrec(tcur, level);
2094         XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
2095
2096         error = xfs_btree_increment(tcur, level, &i);
2097         if (error)
2098                 goto error1;
2099
2100         error = xfs_btree_updkey(tcur, rkp, level + 1);
2101         if (error)
2102                 goto error1;
2103
2104         xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2105
2106         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2107         *stat = 1;
2108         return 0;
2109
2110 out0:
2111         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2112         *stat = 0;
2113         return 0;
2114
2115 error0:
2116         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2117         return error;
2118
2119 error1:
2120         XFS_BTREE_TRACE_CURSOR(tcur, XBT_ERROR);
2121         xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2122         return error;
2123 }
2124
2125 /*
2126  * Split cur/level block in half.
2127  * Return new block number and the key to its first
2128  * record (to be inserted into parent).
2129  */
2130 STATIC int                                      /* error */
2131 xfs_btree_split(
2132         struct xfs_btree_cur    *cur,
2133         int                     level,
2134         union xfs_btree_ptr     *ptrp,
2135         union xfs_btree_key     *key,
2136         struct xfs_btree_cur    **curp,
2137         int                     *stat)          /* success/failure */
2138 {
2139         union xfs_btree_ptr     lptr;           /* left sibling block ptr */
2140         struct xfs_buf          *lbp;           /* left buffer pointer */
2141         struct xfs_btree_block  *left;          /* left btree block */
2142         union xfs_btree_ptr     rptr;           /* right sibling block ptr */
2143         struct xfs_buf          *rbp;           /* right buffer pointer */
2144         struct xfs_btree_block  *right;         /* right btree block */
2145         union xfs_btree_ptr     rrptr;          /* right-right sibling ptr */
2146         struct xfs_buf          *rrbp;          /* right-right buffer pointer */
2147         struct xfs_btree_block  *rrblock;       /* right-right btree block */
2148         int                     lrecs;
2149         int                     rrecs;
2150         int                     src_index;
2151         int                     error;          /* error return value */
2152 #ifdef DEBUG
2153         int                     i;
2154 #endif
2155
2156         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2157         XFS_BTREE_TRACE_ARGIPK(cur, level, *ptrp, key);
2158
2159         XFS_BTREE_STATS_INC(cur, split);
2160
2161         /* Set up left block (current one). */
2162         left = xfs_btree_get_block(cur, level, &lbp);
2163
2164 #ifdef DEBUG
2165         error = xfs_btree_check_block(cur, left, level, lbp);
2166         if (error)
2167                 goto error0;
2168 #endif
2169
2170         xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2171
2172         /* Allocate the new block. If we can't do it, we're toast. Give up. */
2173         error = cur->bc_ops->alloc_block(cur, &lptr, &rptr, 1, stat);
2174         if (error)
2175                 goto error0;
2176         if (*stat == 0)
2177                 goto out0;
2178         XFS_BTREE_STATS_INC(cur, alloc);
2179
2180         /* Set up the new block as "right". */
2181         error = xfs_btree_get_buf_block(cur, &rptr, 0, &right, &rbp);
2182         if (error)
2183                 goto error0;
2184
2185         /* Fill in the btree header for the new right block. */
2186         xfs_btree_init_block(cur, xfs_btree_get_level(left), 0, right);
2187
2188         /*
2189          * Split the entries between the old and the new block evenly.
2190          * Make sure that if there's an odd number of entries now, that
2191          * each new block will have the same number of entries.
2192          */
2193         lrecs = xfs_btree_get_numrecs(left);
2194         rrecs = lrecs / 2;
2195         if ((lrecs & 1) && cur->bc_ptrs[level] <= rrecs + 1)
2196                 rrecs++;
2197         src_index = (lrecs - rrecs + 1);
2198
2199         XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2200
2201         /*
2202          * Copy btree block entries from the left block over to the
2203          * new block, the right. Update the right block and log the
2204          * changes.
2205          */
2206         if (level > 0) {
2207                 /* It's a non-leaf.  Move keys and pointers. */
2208                 union xfs_btree_key     *lkp;   /* left btree key */
2209                 union xfs_btree_ptr     *lpp;   /* left address pointer */
2210                 union xfs_btree_key     *rkp;   /* right btree key */
2211                 union xfs_btree_ptr     *rpp;   /* right address pointer */
2212
2213                 lkp = xfs_btree_key_addr(cur, src_index, left);
2214                 lpp = xfs_btree_ptr_addr(cur, src_index, left);
2215                 rkp = xfs_btree_key_addr(cur, 1, right);
2216                 rpp = xfs_btree_ptr_addr(cur, 1, right);
2217
2218 #ifdef DEBUG
2219                 for (i = src_index; i < rrecs; i++) {
2220                         error = xfs_btree_check_ptr(cur, lpp, i, level);
2221                         if (error)
2222                                 goto error0;
2223                 }
2224 #endif
2225
2226                 xfs_btree_copy_keys(cur, rkp, lkp, rrecs);
2227                 xfs_btree_copy_ptrs(cur, rpp, lpp, rrecs);
2228
2229                 xfs_btree_log_keys(cur, rbp, 1, rrecs);
2230                 xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2231
2232                 /* Grab the keys to the entries moved to the right block */
2233                 xfs_btree_copy_keys(cur, key, rkp, 1);
2234         } else {
2235                 /* It's a leaf.  Move records.  */
2236                 union xfs_btree_rec     *lrp;   /* left record pointer */
2237                 union xfs_btree_rec     *rrp;   /* right record pointer */
2238
2239                 lrp = xfs_btree_rec_addr(cur, src_index, left);
2240                 rrp = xfs_btree_rec_addr(cur, 1, right);
2241
2242                 xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
2243                 xfs_btree_log_recs(cur, rbp, 1, rrecs);
2244
2245                 cur->bc_ops->init_key_from_rec(key,
2246                         xfs_btree_rec_addr(cur, 1, right));
2247         }
2248
2249
2250         /*
2251          * Find the left block number by looking in the buffer.
2252          * Adjust numrecs, sibling pointers.
2253          */
2254         xfs_btree_get_sibling(cur, left, &rrptr, XFS_BB_RIGHTSIB);
2255         xfs_btree_set_sibling(cur, right, &rrptr, XFS_BB_RIGHTSIB);
2256         xfs_btree_set_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2257         xfs_btree_set_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2258
2259         lrecs -= rrecs;
2260         xfs_btree_set_numrecs(left, lrecs);
2261         xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
2262
2263         xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
2264         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
2265
2266         /*
2267          * If there's a block to the new block's right, make that block
2268          * point back to right instead of to left.
2269          */
2270         if (!xfs_btree_ptr_is_null(cur, &rrptr)) {
2271                 error = xfs_btree_read_buf_block(cur, &rrptr, level,
2272                                                         0, &rrblock, &rrbp);
2273                 if (error)
2274                         goto error0;
2275                 xfs_btree_set_sibling(cur, rrblock, &rptr, XFS_BB_LEFTSIB);
2276                 xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
2277         }
2278         /*
2279          * If the cursor is really in the right block, move it there.
2280          * If it's just pointing past the last entry in left, then we'll
2281          * insert there, so don't change anything in that case.
2282          */
2283         if (cur->bc_ptrs[level] > lrecs + 1) {
2284                 xfs_btree_setbuf(cur, level, rbp);
2285                 cur->bc_ptrs[level] -= lrecs;
2286         }
2287         /*
2288          * If there are more levels, we'll need another cursor which refers
2289          * the right block, no matter where this cursor was.
2290          */
2291         if (level + 1 < cur->bc_nlevels) {
2292                 error = xfs_btree_dup_cursor(cur, curp);
2293                 if (error)
2294                         goto error0;
2295                 (*curp)->bc_ptrs[level + 1]++;
2296         }
2297         *ptrp = rptr;
2298         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2299         *stat = 1;
2300         return 0;
2301 out0:
2302         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2303         *stat = 0;
2304         return 0;
2305
2306 error0:
2307         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2308         return error;
2309 }
2310
2311 /*
2312  * Copy the old inode root contents into a real block and make the
2313  * broot point to it.
2314  */
2315 int                                             /* error */
2316 xfs_btree_new_iroot(
2317         struct xfs_btree_cur    *cur,           /* btree cursor */
2318         int                     *logflags,      /* logging flags for inode */
2319         int                     *stat)          /* return status - 0 fail */
2320 {
2321         struct xfs_buf          *cbp;           /* buffer for cblock */
2322         struct xfs_btree_block  *block;         /* btree block */
2323         struct xfs_btree_block  *cblock;        /* child btree block */
2324         union xfs_btree_key     *ckp;           /* child key pointer */
2325         union xfs_btree_ptr     *cpp;           /* child ptr pointer */
2326         union xfs_btree_key     *kp;            /* pointer to btree key */
2327         union xfs_btree_ptr     *pp;            /* pointer to block addr */
2328         union xfs_btree_ptr     nptr;           /* new block addr */
2329         int                     level;          /* btree level */
2330         int                     error;          /* error return code */
2331 #ifdef DEBUG
2332         int                     i;              /* loop counter */
2333 #endif
2334
2335         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2336         XFS_BTREE_STATS_INC(cur, newroot);
2337
2338         ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
2339
2340         level = cur->bc_nlevels - 1;
2341
2342         block = xfs_btree_get_iroot(cur);
2343         pp = xfs_btree_ptr_addr(cur, 1, block);
2344
2345         /* Allocate the new block. If we can't do it, we're toast. Give up. */
2346         error = cur->bc_ops->alloc_block(cur, pp, &nptr, 1, stat);
2347         if (error)
2348                 goto error0;
2349         if (*stat == 0) {
2350                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2351                 return 0;
2352         }
2353         XFS_BTREE_STATS_INC(cur, alloc);
2354
2355         /* Copy the root into a real block. */
2356         error = xfs_btree_get_buf_block(cur, &nptr, 0, &cblock, &cbp);
2357         if (error)
2358                 goto error0;
2359
2360         memcpy(cblock, block, xfs_btree_block_len(cur));
2361
2362         be16_add_cpu(&block->bb_level, 1);
2363         xfs_btree_set_numrecs(block, 1);
2364         cur->bc_nlevels++;
2365         cur->bc_ptrs[level + 1] = 1;
2366
2367         kp = xfs_btree_key_addr(cur, 1, block);
2368         ckp = xfs_btree_key_addr(cur, 1, cblock);
2369         xfs_btree_copy_keys(cur, ckp, kp, xfs_btree_get_numrecs(cblock));
2370
2371         cpp = xfs_btree_ptr_addr(cur, 1, cblock);
2372 #ifdef DEBUG
2373         for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
2374                 error = xfs_btree_check_ptr(cur, pp, i, level);
2375                 if (error)
2376                         goto error0;
2377         }
2378 #endif
2379         xfs_btree_copy_ptrs(cur, cpp, pp, xfs_btree_get_numrecs(cblock));
2380
2381 #ifdef DEBUG
2382         error = xfs_btree_check_ptr(cur, &nptr, 0, level);
2383         if (error)
2384                 goto error0;
2385 #endif
2386         xfs_btree_copy_ptrs(cur, pp, &nptr, 1);
2387
2388         xfs_iroot_realloc(cur->bc_private.b.ip,
2389                           1 - xfs_btree_get_numrecs(cblock),
2390                           cur->bc_private.b.whichfork);
2391
2392         xfs_btree_setbuf(cur, level, cbp);
2393
2394         /*
2395          * Do all this logging at the end so that
2396          * the root is at the right level.
2397          */
2398         xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
2399         xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
2400         xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
2401
2402         *logflags |=
2403                 XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_private.b.whichfork);
2404         *stat = 1;
2405         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2406         return 0;
2407 error0:
2408         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2409         return error;
2410 }
2411
2412 /*
2413  * Allocate a new root block, fill it in.
2414  */
2415 STATIC int                              /* error */
2416 xfs_btree_new_root(
2417         struct xfs_btree_cur    *cur,   /* btree cursor */
2418         int                     *stat)  /* success/failure */
2419 {
2420         struct xfs_btree_block  *block; /* one half of the old root block */
2421         struct xfs_buf          *bp;    /* buffer containing block */
2422         int                     error;  /* error return value */
2423         struct xfs_buf          *lbp;   /* left buffer pointer */
2424         struct xfs_btree_block  *left;  /* left btree block */
2425         struct xfs_buf          *nbp;   /* new (root) buffer */
2426         struct xfs_btree_block  *new;   /* new (root) btree block */
2427         int                     nptr;   /* new value for key index, 1 or 2 */
2428         struct xfs_buf          *rbp;   /* right buffer pointer */
2429         struct xfs_btree_block  *right; /* right btree block */
2430         union xfs_btree_ptr     rptr;
2431         union xfs_btree_ptr     lptr;
2432
2433         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2434         XFS_BTREE_STATS_INC(cur, newroot);
2435
2436         /* initialise our start point from the cursor */
2437         cur->bc_ops->init_ptr_from_cur(cur, &rptr);
2438
2439         /* Allocate the new block. If we can't do it, we're toast. Give up. */
2440         error = cur->bc_ops->alloc_block(cur, &rptr, &lptr, 1, stat);
2441         if (error)
2442                 goto error0;
2443         if (*stat == 0)
2444                 goto out0;
2445         XFS_BTREE_STATS_INC(cur, alloc);
2446
2447         /* Set up the new block. */
2448         error = xfs_btree_get_buf_block(cur, &lptr, 0, &new, &nbp);
2449         if (error)
2450                 goto error0;
2451
2452         /* Set the root in the holding structure  increasing the level by 1. */
2453         cur->bc_ops->set_root(cur, &lptr, 1);
2454
2455         /*
2456          * At the previous root level there are now two blocks: the old root,
2457          * and the new block generated when it was split.  We don't know which
2458          * one the cursor is pointing at, so we set up variables "left" and
2459          * "right" for each case.
2460          */
2461         block = xfs_btree_get_block(cur, cur->bc_nlevels - 1, &bp);
2462
2463 #ifdef DEBUG
2464         error = xfs_btree_check_block(cur, block, cur->bc_nlevels - 1, bp);
2465         if (error)
2466                 goto error0;
2467 #endif
2468
2469         xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
2470         if (!xfs_btree_ptr_is_null(cur, &rptr)) {
2471                 /* Our block is left, pick up the right block. */
2472                 lbp = bp;
2473                 xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2474                 left = block;
2475                 error = xfs_btree_read_buf_block(cur, &rptr,
2476                                         cur->bc_nlevels - 1, 0, &right, &rbp);
2477                 if (error)
2478                         goto error0;
2479                 bp = rbp;
2480                 nptr = 1;
2481         } else {
2482                 /* Our block is right, pick up the left block. */
2483                 rbp = bp;
2484                 xfs_btree_buf_to_ptr(cur, rbp, &rptr);
2485                 right = block;
2486                 xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2487                 error = xfs_btree_read_buf_block(cur, &lptr,
2488                                         cur->bc_nlevels - 1, 0, &left, &lbp);
2489                 if (error)
2490                         goto error0;
2491                 bp = lbp;
2492                 nptr = 2;
2493         }
2494         /* Fill in the new block's btree header and log it. */
2495         xfs_btree_init_block(cur, cur->bc_nlevels, 2, new);
2496         xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
2497         ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
2498                         !xfs_btree_ptr_is_null(cur, &rptr));
2499
2500         /* Fill in the key data in the new root. */
2501         if (xfs_btree_get_level(left) > 0) {
2502                 xfs_btree_copy_keys(cur,
2503                                 xfs_btree_key_addr(cur, 1, new),
2504                                 xfs_btree_key_addr(cur, 1, left), 1);
2505                 xfs_btree_copy_keys(cur,
2506                                 xfs_btree_key_addr(cur, 2, new),
2507                                 xfs_btree_key_addr(cur, 1, right), 1);
2508         } else {
2509                 cur->bc_ops->init_key_from_rec(
2510                                 xfs_btree_key_addr(cur, 1, new),
2511                                 xfs_btree_rec_addr(cur, 1, left));
2512                 cur->bc_ops->init_key_from_rec(
2513                                 xfs_btree_key_addr(cur, 2, new),
2514                                 xfs_btree_rec_addr(cur, 1, right));
2515         }
2516         xfs_btree_log_keys(cur, nbp, 1, 2);
2517
2518         /* Fill in the pointer data in the new root. */
2519         xfs_btree_copy_ptrs(cur,
2520                 xfs_btree_ptr_addr(cur, 1, new), &lptr, 1);
2521         xfs_btree_copy_ptrs(cur,
2522                 xfs_btree_ptr_addr(cur, 2, new), &rptr, 1);
2523         xfs_btree_log_ptrs(cur, nbp, 1, 2);
2524
2525         /* Fix up the cursor. */
2526         xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
2527         cur->bc_ptrs[cur->bc_nlevels] = nptr;
2528         cur->bc_nlevels++;
2529         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2530         *stat = 1;
2531         return 0;
2532 error0:
2533         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2534         return error;
2535 out0:
2536         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2537         *stat = 0;
2538         return 0;
2539 }
2540
2541 STATIC int
2542 xfs_btree_make_block_unfull(
2543         struct xfs_btree_cur    *cur,   /* btree cursor */
2544         int                     level,  /* btree level */
2545         int                     numrecs,/* # of recs in block */
2546         int                     *oindex,/* old tree index */
2547         int                     *index, /* new tree index */
2548         union xfs_btree_ptr     *nptr,  /* new btree ptr */
2549         struct xfs_btree_cur    **ncur, /* new btree cursor */
2550         union xfs_btree_rec     *nrec,  /* new record */
2551         int                     *stat)
2552 {
2553         union xfs_btree_key     key;    /* new btree key value */
2554         int                     error = 0;
2555
2556         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2557             level == cur->bc_nlevels - 1) {
2558                 struct xfs_inode *ip = cur->bc_private.b.ip;
2559
2560                 if (numrecs < cur->bc_ops->get_dmaxrecs(cur, level)) {
2561                         /* A root block that can be made bigger. */
2562
2563                         xfs_iroot_realloc(ip, 1, cur->bc_private.b.whichfork);
2564                 } else {
2565                         /* A root block that needs replacing */
2566                         int     logflags = 0;
2567
2568                         error = xfs_btree_new_iroot(cur, &logflags, stat);
2569                         if (error || *stat == 0)
2570                                 return error;
2571
2572                         xfs_trans_log_inode(cur->bc_tp, ip, logflags);
2573                 }
2574
2575                 return 0;
2576         }
2577
2578         /* First, try shifting an entry to the right neighbor. */
2579         error = xfs_btree_rshift(cur, level, stat);
2580         if (error || *stat)
2581                 return error;
2582
2583         /* Next, try shifting an entry to the left neighbor. */
2584         error = xfs_btree_lshift(cur, level, stat);
2585         if (error)
2586                 return error;
2587
2588         if (*stat) {
2589                 *oindex = *index = cur->bc_ptrs[level];
2590                 return 0;
2591         }
2592
2593         /*
2594          * Next, try splitting the current block in half.
2595          *
2596          * If this works we have to re-set our variables because we
2597          * could be in a different block now.
2598          */
2599         error = xfs_btree_split(cur, level, nptr, &key, ncur, stat);
2600         if (error || *stat == 0)
2601                 return error;
2602
2603
2604         *index = cur->bc_ptrs[level];
2605         cur->bc_ops->init_rec_from_key(&key, nrec);
2606         return 0;
2607 }
2608
2609 /*
2610  * Insert one record/level.  Return information to the caller
2611  * allowing the next level up to proceed if necessary.
2612  */
2613 STATIC int
2614 xfs_btree_insrec(
2615         struct xfs_btree_cur    *cur,   /* btree cursor */
2616         int                     level,  /* level to insert record at */
2617         union xfs_btree_ptr     *ptrp,  /* i/o: block number inserted */
2618         union xfs_btree_rec     *recp,  /* i/o: record data inserted */
2619         struct xfs_btree_cur    **curp, /* output: new cursor replacing cur */
2620         int                     *stat)  /* success/failure */
2621 {
2622         struct xfs_btree_block  *block; /* btree block */
2623         struct xfs_buf          *bp;    /* buffer for block */
2624         union xfs_btree_key     key;    /* btree key */
2625         union xfs_btree_ptr     nptr;   /* new block ptr */
2626         struct xfs_btree_cur    *ncur;  /* new btree cursor */
2627         union xfs_btree_rec     nrec;   /* new record count */
2628         int                     optr;   /* old key/record index */
2629         int                     ptr;    /* key/record index */
2630         int                     numrecs;/* number of records */
2631         int                     error;  /* error return value */
2632 #ifdef DEBUG
2633         int                     i;
2634 #endif
2635
2636         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2637         XFS_BTREE_TRACE_ARGIPR(cur, level, *ptrp, recp);
2638
2639         ncur = NULL;
2640
2641         /*
2642          * If we have an external root pointer, and we've made it to the
2643          * root level, allocate a new root block and we're done.
2644          */
2645         if (!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2646             (level >= cur->bc_nlevels)) {
2647                 error = xfs_btree_new_root(cur, stat);
2648                 xfs_btree_set_ptr_null(cur, ptrp);
2649
2650                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2651                 return error;
2652         }
2653
2654         /* If we're off the left edge, return failure. */
2655         ptr = cur->bc_ptrs[level];
2656         if (ptr == 0) {
2657                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2658                 *stat = 0;
2659                 return 0;
2660         }
2661
2662         /* Make a key out of the record data to be inserted, and save it. */
2663         cur->bc_ops->init_key_from_rec(&key, recp);
2664
2665         optr = ptr;
2666
2667         XFS_BTREE_STATS_INC(cur, insrec);
2668
2669         /* Get pointers to the btree buffer and block. */
2670         block = xfs_btree_get_block(cur, level, &bp);
2671         numrecs = xfs_btree_get_numrecs(block);
2672
2673 #ifdef DEBUG
2674         error = xfs_btree_check_block(cur, block, level, bp);
2675         if (error)
2676                 goto error0;
2677
2678         /* Check that the new entry is being inserted in the right place. */
2679         if (ptr <= numrecs) {
2680                 if (level == 0) {
2681                         ASSERT(cur->bc_ops->recs_inorder(cur, recp,
2682                                 xfs_btree_rec_addr(cur, ptr, block)));
2683                 } else {
2684                         ASSERT(cur->bc_ops->keys_inorder(cur, &key,
2685                                 xfs_btree_key_addr(cur, ptr, block)));
2686                 }
2687         }
2688 #endif
2689
2690         /*
2691          * If the block is full, we can't insert the new entry until we
2692          * make the block un-full.
2693          */
2694         xfs_btree_set_ptr_null(cur, &nptr);
2695         if (numrecs == cur->bc_ops->get_maxrecs(cur, level)) {
2696                 error = xfs_btree_make_block_unfull(cur, level, numrecs,
2697                                         &optr, &ptr, &nptr, &ncur, &nrec, stat);
2698                 if (error || *stat == 0)
2699                         goto error0;
2700         }
2701
2702         /*
2703          * The current block may have changed if the block was
2704          * previously full and we have just made space in it.
2705          */
2706         block = xfs_btree_get_block(cur, level, &bp);
2707         numrecs = xfs_btree_get_numrecs(block);
2708
2709 #ifdef DEBUG
2710         error = xfs_btree_check_block(cur, block, level, bp);
2711         if (error)
2712                 return error;
2713 #endif
2714
2715         /*
2716          * At this point we know there's room for our new entry in the block
2717          * we're pointing at.
2718          */
2719         XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr + 1);
2720
2721         if (level > 0) {
2722                 /* It's a nonleaf. make a hole in the keys and ptrs */
2723                 union xfs_btree_key     *kp;
2724                 union xfs_btree_ptr     *pp;
2725
2726                 kp = xfs_btree_key_addr(cur, ptr, block);
2727                 pp = xfs_btree_ptr_addr(cur, ptr, block);
2728
2729 #ifdef DEBUG
2730                 for (i = numrecs - ptr; i >= 0; i--) {
2731                         error = xfs_btree_check_ptr(cur, pp, i, level);
2732                         if (error)
2733                                 return error;
2734                 }
2735 #endif
2736
2737                 xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1);
2738                 xfs_btree_shift_ptrs(cur, pp, 1, numrecs - ptr + 1);
2739
2740 #ifdef DEBUG
2741                 error = xfs_btree_check_ptr(cur, ptrp, 0, level);
2742                 if (error)
2743                         goto error0;
2744 #endif
2745
2746                 /* Now put the new data in, bump numrecs and log it. */
2747                 xfs_btree_copy_keys(cur, kp, &key, 1);
2748                 xfs_btree_copy_ptrs(cur, pp, ptrp, 1);
2749                 numrecs++;
2750                 xfs_btree_set_numrecs(block, numrecs);
2751                 xfs_btree_log_ptrs(cur, bp, ptr, numrecs);
2752                 xfs_btree_log_keys(cur, bp, ptr, numrecs);
2753 #ifdef DEBUG
2754                 if (ptr < numrecs) {
2755                         ASSERT(cur->bc_ops->keys_inorder(cur, kp,
2756                                 xfs_btree_key_addr(cur, ptr + 1, block)));
2757                 }
2758 #endif
2759         } else {
2760                 /* It's a leaf. make a hole in the records */
2761                 union xfs_btree_rec             *rp;
2762
2763                 rp = xfs_btree_rec_addr(cur, ptr, block);
2764
2765                 xfs_btree_shift_recs(cur, rp, 1, numrecs - ptr + 1);
2766
2767                 /* Now put the new data in, bump numrecs and log it. */
2768                 xfs_btree_copy_recs(cur, rp, recp, 1);
2769                 xfs_btree_set_numrecs(block, ++numrecs);
2770                 xfs_btree_log_recs(cur, bp, ptr, numrecs);
2771 #ifdef DEBUG
2772                 if (ptr < numrecs) {
2773                         ASSERT(cur->bc_ops->recs_inorder(cur, rp,
2774                                 xfs_btree_rec_addr(cur, ptr + 1, block)));
2775                 }
2776 #endif
2777         }
2778
2779         /* Log the new number of records in the btree header. */
2780         xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
2781
2782         /* If we inserted at the start of a block, update the parents' keys. */
2783         if (optr == 1) {
2784                 error = xfs_btree_updkey(cur, &key, level + 1);
2785                 if (error)
2786                         goto error0;
2787         }
2788
2789         /*
2790          * If we are tracking the last record in the tree and
2791          * we are at the far right edge of the tree, update it.
2792          */
2793         if (xfs_btree_is_lastrec(cur, block, level)) {
2794                 cur->bc_ops->update_lastrec(cur, block, recp,
2795                                             ptr, LASTREC_INSREC);
2796         }
2797
2798         /*
2799          * Return the new block number, if any.
2800          * If there is one, give back a record value and a cursor too.
2801          */
2802         *ptrp = nptr;
2803         if (!xfs_btree_ptr_is_null(cur, &nptr)) {
2804                 *recp = nrec;
2805                 *curp = ncur;
2806         }
2807
2808         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2809         *stat = 1;
2810         return 0;
2811
2812 error0:
2813         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2814         return error;
2815 }
2816
2817 /*
2818  * Insert the record at the point referenced by cur.
2819  *
2820  * A multi-level split of the tree on insert will invalidate the original
2821  * cursor.  All callers of this function should assume that the cursor is
2822  * no longer valid and revalidate it.
2823  */
2824 int
2825 xfs_btree_insert(
2826         struct xfs_btree_cur    *cur,
2827         int                     *stat)
2828 {
2829         int                     error;  /* error return value */
2830         int                     i;      /* result value, 0 for failure */
2831         int                     level;  /* current level number in btree */
2832         union xfs_btree_ptr     nptr;   /* new block number (split result) */
2833         struct xfs_btree_cur    *ncur;  /* new cursor (split result) */
2834         struct xfs_btree_cur    *pcur;  /* previous level's cursor */
2835         union xfs_btree_rec     rec;    /* record to insert */
2836
2837         level = 0;
2838         ncur = NULL;
2839         pcur = cur;
2840
2841         xfs_btree_set_ptr_null(cur, &nptr);
2842         cur->bc_ops->init_rec_from_cur(cur, &rec);
2843
2844         /*
2845          * Loop going up the tree, starting at the leaf level.
2846          * Stop when we don't get a split block, that must mean that
2847          * the insert is finished with this level.
2848          */
2849         do {
2850                 /*
2851                  * Insert nrec/nptr into this level of the tree.
2852                  * Note if we fail, nptr will be null.
2853                  */
2854                 error = xfs_btree_insrec(pcur, level, &nptr, &rec, &ncur, &i);
2855                 if (error) {
2856                         if (pcur != cur)
2857                                 xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
2858                         goto error0;
2859                 }
2860
2861                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
2862                 level++;
2863
2864                 /*
2865                  * See if the cursor we just used is trash.
2866                  * Can't trash the caller's cursor, but otherwise we should
2867                  * if ncur is a new cursor or we're about to be done.
2868                  */
2869                 if (pcur != cur &&
2870                     (ncur || xfs_btree_ptr_is_null(cur, &nptr))) {
2871                         /* Save the state from the cursor before we trash it */
2872                         if (cur->bc_ops->update_cursor)
2873                                 cur->bc_ops->update_cursor(pcur, cur);
2874                         cur->bc_nlevels = pcur->bc_nlevels;
2875                         xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
2876                 }
2877                 /* If we got a new cursor, switch to it. */
2878                 if (ncur) {
2879                         pcur = ncur;
2880                         ncur = NULL;
2881                 }
2882         } while (!xfs_btree_ptr_is_null(cur, &nptr));
2883
2884         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2885         *stat = i;
2886         return 0;
2887 error0:
2888         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2889         return error;
2890 }
2891
2892 /*
2893  * Try to merge a non-leaf block back into the inode root.
2894  *
2895  * Note: the killroot names comes from the fact that we're effectively
2896  * killing the old root block.  But because we can't just delete the
2897  * inode we have to copy the single block it was pointing to into the
2898  * inode.
2899  */
2900 STATIC int
2901 xfs_btree_kill_iroot(
2902         struct xfs_btree_cur    *cur)
2903 {
2904         int                     whichfork = cur->bc_private.b.whichfork;
2905         struct xfs_inode        *ip = cur->bc_private.b.ip;
2906         struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, whichfork);
2907         struct xfs_btree_block  *block;
2908         struct xfs_btree_block  *cblock;
2909         union xfs_btree_key     *kp;
2910         union xfs_btree_key     *ckp;
2911         union xfs_btree_ptr     *pp;
2912         union xfs_btree_ptr     *cpp;
2913         struct xfs_buf          *cbp;
2914         int                     level;
2915         int                     index;
2916         int                     numrecs;
2917 #ifdef DEBUG
2918         union xfs_btree_ptr     ptr;
2919         int                     i;
2920 #endif
2921
2922         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2923
2924         ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
2925         ASSERT(cur->bc_nlevels > 1);
2926
2927         /*
2928          * Don't deal with the root block needs to be a leaf case.
2929          * We're just going to turn the thing back into extents anyway.
2930          */
2931         level = cur->bc_nlevels - 1;
2932         if (level == 1)
2933                 goto out0;
2934
2935         /*
2936          * Give up if the root has multiple children.
2937          */
2938         block = xfs_btree_get_iroot(cur);
2939         if (xfs_btree_get_numrecs(block) != 1)
2940                 goto out0;
2941
2942         cblock = xfs_btree_get_block(cur, level - 1, &cbp);
2943         numrecs = xfs_btree_get_numrecs(cblock);
2944
2945         /*
2946          * Only do this if the next level will fit.
2947          * Then the data must be copied up to the inode,
2948          * instead of freeing the root you free the next level.
2949          */
2950         if (numrecs > cur->bc_ops->get_dmaxrecs(cur, level))
2951                 goto out0;
2952
2953         XFS_BTREE_STATS_INC(cur, killroot);
2954
2955 #ifdef DEBUG
2956         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
2957         ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
2958         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
2959         ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
2960 #endif
2961
2962         index = numrecs - cur->bc_ops->get_maxrecs(cur, level);
2963         if (index) {
2964                 xfs_iroot_realloc(cur->bc_private.b.ip, index,
2965                                   cur->bc_private.b.whichfork);
2966                 block = ifp->if_broot;
2967         }
2968
2969         be16_add_cpu(&block->bb_numrecs, index);
2970         ASSERT(block->bb_numrecs == cblock->bb_numrecs);
2971
2972         kp = xfs_btree_key_addr(cur, 1, block);
2973         ckp = xfs_btree_key_addr(cur, 1, cblock);
2974         xfs_btree_copy_keys(cur, kp, ckp, numrecs);
2975
2976         pp = xfs_btree_ptr_addr(cur, 1, block);
2977         cpp = xfs_btree_ptr_addr(cur, 1, cblock);
2978 #ifdef DEBUG
2979         for (i = 0; i < numrecs; i++) {
2980                 int             error;
2981
2982                 error = xfs_btree_check_ptr(cur, cpp, i, level - 1);
2983                 if (error) {
2984                         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2985                         return error;
2986                 }
2987         }
2988 #endif
2989         xfs_btree_copy_ptrs(cur, pp, cpp, numrecs);
2990
2991         cur->bc_ops->free_block(cur, cbp);
2992         XFS_BTREE_STATS_INC(cur, free);
2993
2994         cur->bc_bufs[level - 1] = NULL;
2995         be16_add_cpu(&block->bb_level, -1);
2996         xfs_trans_log_inode(cur->bc_tp, ip,
2997                 XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_private.b.whichfork));
2998         cur->bc_nlevels--;
2999 out0:
3000         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3001         return 0;
3002 }
3003
3004 /*
3005  * Kill the current root node, and replace it with it's only child node.
3006  */
3007 STATIC int
3008 xfs_btree_kill_root(
3009         struct xfs_btree_cur    *cur,
3010         struct xfs_buf          *bp,
3011         int                     level,
3012         union xfs_btree_ptr     *newroot)
3013 {
3014         int                     error;
3015
3016         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
3017         XFS_BTREE_STATS_INC(cur, killroot);
3018
3019         /*
3020          * Update the root pointer, decreasing the level by 1 and then
3021          * free the old root.
3022          */
3023         cur->bc_ops->set_root(cur, newroot, -1);
3024
3025         error = cur->bc_ops->free_block(cur, bp);
3026         if (error) {
3027                 XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
3028                 return error;
3029         }
3030
3031         XFS_BTREE_STATS_INC(cur, free);
3032
3033         cur->bc_bufs[level] = NULL;
3034         cur->bc_ra[level] = 0;
3035         cur->bc_nlevels--;
3036
3037         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3038         return 0;
3039 }
3040
3041 STATIC int
3042 xfs_btree_dec_cursor(
3043         struct xfs_btree_cur    *cur,
3044         int                     level,
3045         int                     *stat)
3046 {
3047         int                     error;
3048         int                     i;
3049
3050         if (level > 0) {
3051                 error = xfs_btree_decrement(cur, level, &i);
3052                 if (error)
3053                         return error;
3054         }
3055
3056         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3057         *stat = 1;
3058         return 0;
3059 }
3060
3061 /*
3062  * Single level of the btree record deletion routine.
3063  * Delete record pointed to by cur/level.
3064  * Remove the record from its block then rebalance the tree.
3065  * Return 0 for error, 1 for done, 2 to go on to the next level.
3066  */
3067 STATIC int                                      /* error */
3068 xfs_btree_delrec(
3069         struct xfs_btree_cur    *cur,           /* btree cursor */
3070         int                     level,          /* level removing record from */
3071         int                     *stat)          /* fail/done/go-on */
3072 {
3073         struct xfs_btree_block  *block;         /* btree block */
3074         union xfs_btree_ptr     cptr;           /* current block ptr */
3075         struct xfs_buf          *bp;            /* buffer for block */
3076         int                     error;          /* error return value */
3077         int                     i;              /* loop counter */
3078         union xfs_btree_key     key;            /* storage for keyp */
3079         union xfs_btree_key     *keyp = &key;   /* passed to the next level */
3080         union xfs_btree_ptr     lptr;           /* left sibling block ptr */
3081         struct xfs_buf          *lbp;           /* left buffer pointer */
3082         struct xfs_btree_block  *left;          /* left btree block */
3083         int                     lrecs = 0;      /* left record count */
3084         int                     ptr;            /* key/record index */
3085         union xfs_btree_ptr     rptr;           /* right sibling block ptr */
3086         struct xfs_buf          *rbp;           /* right buffer pointer */
3087         struct xfs_btree_block  *right;         /* right btree block */
3088         struct xfs_btree_block  *rrblock;       /* right-right btree block */
3089         struct xfs_buf          *rrbp;          /* right-right buffer pointer */
3090         int                     rrecs = 0;      /* right record count */
3091         struct xfs_btree_cur    *tcur;          /* temporary btree cursor */
3092         int                     numrecs;        /* temporary numrec count */
3093
3094         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
3095         XFS_BTREE_TRACE_ARGI(cur, level);
3096
3097         tcur = NULL;
3098
3099         /* Get the index of the entry being deleted, check for nothing there. */
3100         ptr = cur->bc_ptrs[level];
3101         if (ptr == 0) {
3102                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3103                 *stat = 0;
3104                 return 0;
3105         }
3106
3107         /* Get the buffer & block containing the record or key/ptr. */
3108         block = xfs_btree_get_block(cur, level, &bp);
3109         numrecs = xfs_btree_get_numrecs(block);
3110
3111 #ifdef DEBUG
3112         error = xfs_btree_check_block(cur, block, level, bp);
3113         if (error)
3114                 goto error0;
3115 #endif
3116
3117         /* Fail if we're off the end of the block. */
3118         if (ptr > numrecs) {
3119                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3120                 *stat = 0;
3121                 return 0;
3122         }
3123
3124         XFS_BTREE_STATS_INC(cur, delrec);
3125         XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr);
3126
3127         /* Excise the entries being deleted. */
3128         if (level > 0) {
3129                 /* It's a nonleaf. operate on keys and ptrs */
3130                 union xfs_btree_key     *lkp;
3131                 union xfs_btree_ptr     *lpp;
3132
3133                 lkp = xfs_btree_key_addr(cur, ptr + 1, block);
3134                 lpp = xfs_btree_ptr_addr(cur, ptr + 1, block);
3135
3136 #ifdef DEBUG
3137                 for (i = 0; i < numrecs - ptr; i++) {
3138                         error = xfs_btree_check_ptr(cur, lpp, i, level);
3139                         if (error)
3140                                 goto error0;
3141                 }
3142 #endif
3143
3144                 if (ptr < numrecs) {
3145                         xfs_btree_shift_keys(cur, lkp, -1, numrecs - ptr);
3146                         xfs_btree_shift_ptrs(cur, lpp, -1, numrecs - ptr);
3147                         xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
3148                         xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
3149                 }
3150
3151                 /*
3152                  * If it's the first record in the block, we'll need to pass a
3153                  * key up to the next level (updkey).
3154                  */
3155                 if (ptr == 1)
3156                         keyp = xfs_btree_key_addr(cur, 1, block);
3157         } else {
3158                 /* It's a leaf. operate on records */
3159                 if (ptr < numrecs) {
3160                         xfs_btree_shift_recs(cur,
3161                                 xfs_btree_rec_addr(cur, ptr + 1, block),
3162                                 -1, numrecs - ptr);
3163                         xfs_btree_log_recs(cur, bp, ptr, numrecs - 1);
3164                 }
3165
3166                 /*
3167                  * If it's the first record in the block, we'll need a key
3168                  * structure to pass up to the next level (updkey).
3169                  */
3170                 if (ptr == 1) {
3171                         cur->bc_ops->init_key_from_rec(&key,
3172                                         xfs_btree_rec_addr(cur, 1, block));
3173                         keyp = &key;
3174                 }
3175         }
3176
3177         /*
3178          * Decrement and log the number of entries in the block.
3179          */
3180         xfs_btree_set_numrecs(block, --numrecs);
3181         xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3182
3183         /*
3184          * If we are tracking the last record in the tree and
3185          * we are at the far right edge of the tree, update it.
3186          */
3187         if (xfs_btree_is_lastrec(cur, block, level)) {
3188                 cur->bc_ops->update_lastrec(cur, block, NULL,
3189                                             ptr, LASTREC_DELREC);
3190         }
3191
3192         /*
3193          * We're at the root level.  First, shrink the root block in-memory.
3194          * Try to get rid of the next level down.  If we can't then there's
3195          * nothing left to do.
3196          */
3197         if (level == cur->bc_nlevels - 1) {
3198                 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3199                         xfs_iroot_realloc(cur->bc_private.b.ip, -1,
3200                                           cur->bc_private.b.whichfork);
3201
3202                         error = xfs_btree_kill_iroot(cur);
3203                         if (error)
3204                                 goto error0;
3205
3206                         error = xfs_btree_dec_cursor(cur, level, stat);
3207                         if (error)
3208                                 goto error0;
3209                         *stat = 1;
3210                         return 0;
3211                 }
3212
3213                 /*
3214                  * If this is the root level, and there's only one entry left,
3215                  * and it's NOT the leaf level, then we can get rid of this
3216                  * level.
3217                  */
3218                 if (numrecs == 1 && level > 0) {
3219                         union xfs_btree_ptr     *pp;
3220                         /*
3221                          * pp is still set to the first pointer in the block.
3222                          * Make it the new root of the btree.
3223                          */
3224                         pp = xfs_btree_ptr_addr(cur, 1, block);
3225                         error = xfs_btree_kill_root(cur, bp, level, pp);
3226                         if (error)
3227                                 goto error0;
3228                 } else if (level > 0) {
3229                         error = xfs_btree_dec_cursor(cur, level, stat);
3230                         if (error)
3231                                 goto error0;
3232                 }
3233                 *stat = 1;
3234                 return 0;
3235         }
3236
3237         /*
3238          * If we deleted the leftmost entry in the block, update the
3239          * key values above us in the tree.
3240          */
3241         if (ptr == 1) {
3242                 error = xfs_btree_updkey(cur, keyp, level + 1);
3243                 if (error)
3244                         goto error0;
3245         }
3246
3247         /*
3248          * If the number of records remaining in the block is at least
3249          * the minimum, we're done.
3250          */
3251         if (numrecs >= cur->bc_ops->get_minrecs(cur, level)) {
3252                 error = xfs_btree_dec_cursor(cur, level, stat);
3253                 if (error)
3254                         goto error0;
3255                 return 0;
3256         }
3257
3258         /*
3259          * Otherwise, we have to move some records around to keep the
3260          * tree balanced.  Look at the left and right sibling blocks to
3261          * see if we can re-balance by moving only one record.
3262          */
3263         xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3264         xfs_btree_get_sibling(cur, block, &lptr, XFS_BB_LEFTSIB);
3265
3266         if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3267                 /*
3268                  * One child of root, need to get a chance to copy its contents
3269                  * into the root and delete it. Can't go up to next level,
3270                  * there's nothing to delete there.
3271                  */
3272                 if (xfs_btree_ptr_is_null(cur, &rptr) &&
3273                     xfs_btree_ptr_is_null(cur, &lptr) &&
3274                     level == cur->bc_nlevels - 2) {
3275                         error = xfs_btree_kill_iroot(cur);
3276                         if (!error)
3277                                 error = xfs_btree_dec_cursor(cur, level, stat);
3278                         if (error)
3279                                 goto error0;
3280                         return 0;
3281                 }
3282         }
3283
3284         ASSERT(!xfs_btree_ptr_is_null(cur, &rptr) ||
3285                !xfs_btree_ptr_is_null(cur, &lptr));
3286
3287         /*
3288          * Duplicate the cursor so our btree manipulations here won't
3289          * disrupt the next level up.
3290          */
3291         error = xfs_btree_dup_cursor(cur, &tcur);
3292         if (error)
3293                 goto error0;
3294
3295         /*
3296          * If there's a right sibling, see if it's ok to shift an entry
3297          * out of it.
3298          */
3299         if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3300                 /*
3301                  * Move the temp cursor to the last entry in the next block.
3302                  * Actually any entry but the first would suffice.
3303                  */
3304                 i = xfs_btree_lastrec(tcur, level);
3305                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3306
3307                 error = xfs_btree_increment(tcur, level, &i);
3308                 if (error)
3309                         goto error0;
3310                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3311
3312                 i = xfs_btree_lastrec(tcur, level);
3313                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3314
3315                 /* Grab a pointer to the block. */
3316                 right = xfs_btree_get_block(tcur, level, &rbp);
3317 #ifdef DEBUG
3318                 error = xfs_btree_check_block(tcur, right, level, rbp);
3319                 if (error)
3320                         goto error0;
3321 #endif
3322                 /* Grab the current block number, for future use. */
3323                 xfs_btree_get_sibling(tcur, right, &cptr, XFS_BB_LEFTSIB);
3324
3325                 /*
3326                  * If right block is full enough so that removing one entry
3327                  * won't make it too empty, and left-shifting an entry out
3328                  * of right to us works, we're done.
3329                  */
3330                 if (xfs_btree_get_numrecs(right) - 1 >=
3331                     cur->bc_ops->get_minrecs(tcur, level)) {
3332                         error = xfs_btree_lshift(tcur, level, &i);
3333                         if (error)
3334                                 goto error0;
3335                         if (i) {
3336                                 ASSERT(xfs_btree_get_numrecs(block) >=
3337                                        cur->bc_ops->get_minrecs(tcur, level));
3338
3339                                 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3340                                 tcur = NULL;
3341
3342                                 error = xfs_btree_dec_cursor(cur, level, stat);
3343                                 if (error)
3344                                         goto error0;
3345                                 return 0;
3346                         }
3347                 }
3348
3349                 /*
3350                  * Otherwise, grab the number of records in right for
3351                  * future reference, and fix up the temp cursor to point
3352                  * to our block again (last record).
3353                  */
3354                 rrecs = xfs_btree_get_numrecs(right);
3355                 if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3356                         i = xfs_btree_firstrec(tcur, level);
3357                         XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3358
3359                         error = xfs_btree_decrement(tcur, level, &i);
3360                         if (error)
3361                                 goto error0;
3362                         XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3363                 }
3364         }
3365
3366         /*
3367          * If there's a left sibling, see if it's ok to shift an entry
3368          * out of it.
3369          */
3370         if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3371                 /*
3372                  * Move the temp cursor to the first entry in the
3373                  * previous block.
3374                  */
3375                 i = xfs_btree_firstrec(tcur, level);
3376                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3377
3378                 error = xfs_btree_decrement(tcur, level, &i);
3379                 if (error)
3380                         goto error0;
3381                 i = xfs_btree_firstrec(tcur, level);
3382                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3383
3384                 /* Grab a pointer to the block. */
3385                 left = xfs_btree_get_block(tcur, level, &lbp);
3386 #ifdef DEBUG
3387                 error = xfs_btree_check_block(cur, left, level, lbp);
3388                 if (error)
3389                         goto error0;
3390 #endif
3391                 /* Grab the current block number, for future use. */
3392                 xfs_btree_get_sibling(tcur, left, &cptr, XFS_BB_RIGHTSIB);
3393
3394                 /*
3395                  * If left block is full enough so that removing one entry
3396                  * won't make it too empty, and right-shifting an entry out
3397                  * of left to us works, we're done.
3398                  */
3399                 if (xfs_btree_get_numrecs(left) - 1 >=
3400                     cur->bc_ops->get_minrecs(tcur, level)) {
3401                         error = xfs_btree_rshift(tcur, level, &i);
3402                         if (error)
3403                                 goto error0;
3404                         if (i) {
3405                                 ASSERT(xfs_btree_get_numrecs(block) >=
3406                                        cur->bc_ops->get_minrecs(tcur, level));
3407                                 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3408                                 tcur = NULL;
3409                                 if (level == 0)
3410                                         cur->bc_ptrs[0]++;
3411                                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3412                                 *stat = 1;
3413                                 return 0;
3414                         }
3415                 }
3416
3417                 /*
3418                  * Otherwise, grab the number of records in right for
3419                  * future reference.
3420                  */
3421                 lrecs = xfs_btree_get_numrecs(left);
3422         }
3423
3424         /* Delete the temp cursor, we're done with it. */
3425         xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3426         tcur = NULL;
3427
3428         /* If here, we need to do a join to keep the tree balanced. */
3429         ASSERT(!xfs_btree_ptr_is_null(cur, &cptr));
3430
3431         if (!xfs_btree_ptr_is_null(cur, &lptr) &&
3432             lrecs + xfs_btree_get_numrecs(block) <=
3433                         cur->bc_ops->get_maxrecs(cur, level)) {
3434                 /*
3435                  * Set "right" to be the starting block,
3436                  * "left" to be the left neighbor.
3437                  */
3438                 rptr = cptr;
3439                 right = block;
3440                 rbp = bp;
3441                 error = xfs_btree_read_buf_block(cur, &lptr, level,
3442                                                         0, &left, &lbp);
3443                 if (error)
3444                         goto error0;
3445
3446         /*
3447          * If that won't work, see if we can join with the right neighbor block.
3448          */
3449         } else if (!xfs_btree_ptr_is_null(cur, &rptr) &&
3450                    rrecs + xfs_btree_get_numrecs(block) <=
3451                         cur->bc_ops->get_maxrecs(cur, level)) {
3452                 /*
3453                  * Set "left" to be the starting block,
3454                  * "right" to be the right neighbor.
3455                  */
3456                 lptr = cptr;
3457                 left = block;
3458                 lbp = bp;
3459                 error = xfs_btree_read_buf_block(cur, &rptr, level,
3460                                                         0, &right, &rbp);
3461                 if (error)
3462                         goto error0;
3463
3464         /*
3465          * Otherwise, we can't fix the imbalance.
3466          * Just return.  This is probably a logic error, but it's not fatal.
3467          */
3468         } else {
3469                 error = xfs_btree_dec_cursor(cur, level, stat);
3470                 if (error)
3471                         goto error0;
3472                 return 0;
3473         }
3474
3475         rrecs = xfs_btree_get_numrecs(right);
3476         lrecs = xfs_btree_get_numrecs(left);
3477
3478         /*
3479          * We're now going to join "left" and "right" by moving all the stuff
3480          * in "right" to "left" and deleting "right".
3481          */
3482         XFS_BTREE_STATS_ADD(cur, moves, rrecs);
3483         if (level > 0) {
3484                 /* It's a non-leaf.  Move keys and pointers. */
3485                 union xfs_btree_key     *lkp;   /* left btree key */
3486                 union xfs_btree_ptr     *lpp;   /* left address pointer */
3487                 union xfs_btree_key     *rkp;   /* right btree key */
3488                 union xfs_btree_ptr     *rpp;   /* right address pointer */
3489
3490                 lkp = xfs_btree_key_addr(cur, lrecs + 1, left);
3491                 lpp = xfs_btree_ptr_addr(cur, lrecs + 1, left);
3492                 rkp = xfs_btree_key_addr(cur, 1, right);
3493                 rpp = xfs_btree_ptr_addr(cur, 1, right);
3494 #ifdef DEBUG
3495                 for (i = 1; i < rrecs; i++) {
3496                         error = xfs_btree_check_ptr(cur, rpp, i, level);
3497                         if (error)
3498                                 goto error0;
3499                 }
3500 #endif
3501                 xfs_btree_copy_keys(cur, lkp, rkp, rrecs);
3502                 xfs_btree_copy_ptrs(cur, lpp, rpp, rrecs);
3503
3504                 xfs_btree_log_keys(cur, lbp, lrecs + 1, lrecs + rrecs);
3505                 xfs_btree_log_ptrs(cur, lbp, lrecs + 1, lrecs + rrecs);
3506         } else {
3507                 /* It's a leaf.  Move records.  */
3508                 union xfs_btree_rec     *lrp;   /* left record pointer */
3509                 union xfs_btree_rec     *rrp;   /* right record pointer */
3510
3511                 lrp = xfs_btree_rec_addr(cur, lrecs + 1, left);
3512                 rrp = xfs_btree_rec_addr(cur, 1, right);
3513
3514                 xfs_btree_copy_recs(cur, lrp, rrp, rrecs);
3515                 xfs_btree_log_recs(cur, lbp, lrecs + 1, lrecs + rrecs);
3516         }
3517
3518         XFS_BTREE_STATS_INC(cur, join);
3519
3520         /*
3521          * Fix up the number of records and right block pointer in the
3522          * surviving block, and log it.
3523          */
3524         xfs_btree_set_numrecs(left, lrecs + rrecs);
3525         xfs_btree_get_sibling(cur, right, &cptr, XFS_BB_RIGHTSIB),
3526         xfs_btree_set_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
3527         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
3528
3529         /* If there is a right sibling, point it to the remaining block. */
3530         xfs_btree_get_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
3531         if (!xfs_btree_ptr_is_null(cur, &cptr)) {
3532                 error = xfs_btree_read_buf_block(cur, &cptr, level,
3533                                                         0, &rrblock, &rrbp);
3534                 if (error)
3535                         goto error0;
3536                 xfs_btree_set_sibling(cur, rrblock, &lptr, XFS_BB_LEFTSIB);
3537                 xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
3538         }
3539
3540         /* Free the deleted block. */
3541         error = cur->bc_ops->free_block(cur, rbp);
3542         if (error)
3543                 goto error0;
3544         XFS_BTREE_STATS_INC(cur, free);
3545
3546         /*
3547          * If we joined with the left neighbor, set the buffer in the
3548          * cursor to the left block, and fix up the index.
3549          */
3550         if (bp != lbp) {
3551                 cur->bc_bufs[level] = lbp;
3552                 cur->bc_ptrs[level] += lrecs;
3553                 cur->bc_ra[level] = 0;
3554         }
3555         /*
3556          * If we joined with the right neighbor and there's a level above
3557          * us, increment the cursor at that level.
3558          */
3559         else if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) ||
3560                    (level + 1 < cur->bc_nlevels)) {
3561                 error = xfs_btree_increment(cur, level + 1, &i);
3562                 if (error)
3563                         goto error0;
3564         }
3565
3566         /*
3567          * Readjust the ptr at this level if it's not a leaf, since it's
3568          * still pointing at the deletion point, which makes the cursor
3569          * inconsistent.  If this makes the ptr 0, the caller fixes it up.
3570          * We can't use decrement because it would change the next level up.
3571          */
3572         if (level > 0)
3573                 cur->bc_ptrs[level]--;
3574
3575         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3576         /* Return value means the next level up has something to do. */
3577         *stat = 2;
3578         return 0;
3579
3580 error0:
3581         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
3582         if (tcur)
3583                 xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
3584         return error;
3585 }
3586
3587 /*
3588  * Delete the record pointed to by cur.
3589  * The cursor refers to the place where the record was (could be inserted)
3590  * when the operation returns.
3591  */
3592 int                                     /* error */
3593 xfs_btree_delete(
3594         struct xfs_btree_cur    *cur,
3595         int                     *stat)  /* success/failure */
3596 {
3597         int                     error;  /* error return value */
3598         int                     level;
3599         int                     i;
3600
3601         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
3602
3603         /*
3604          * Go up the tree, starting at leaf level.
3605          *
3606          * If 2 is returned then a join was done; go to the next level.
3607          * Otherwise we are done.
3608          */
3609         for (level = 0, i = 2; i == 2; level++) {
3610                 error = xfs_btree_delrec(cur, level, &i);
3611                 if (error)
3612                         goto error0;
3613         }
3614
3615         if (i == 0) {
3616                 for (level = 1; level < cur->bc_nlevels; level++) {
3617                         if (cur->bc_ptrs[level] == 0) {
3618                                 error = xfs_btree_decrement(cur, level, &i);
3619                                 if (error)
3620                                         goto error0;
3621                                 break;
3622                         }
3623                 }
3624         }
3625
3626         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3627         *stat = i;
3628         return 0;
3629 error0:
3630         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
3631         return error;
3632 }
3633
3634 /*
3635  * Get the data from the pointed-to record.
3636  */
3637 int                                     /* error */
3638 xfs_btree_get_rec(
3639         struct xfs_btree_cur    *cur,   /* btree cursor */
3640         union xfs_btree_rec     **recp, /* output: btree record */
3641         int                     *stat)  /* output: success/failure */
3642 {
3643         struct xfs_btree_block  *block; /* btree block */
3644         struct xfs_buf          *bp;    /* buffer pointer */
3645         int                     ptr;    /* record number */
3646 #ifdef DEBUG
3647         int                     error;  /* error return value */
3648 #endif
3649
3650         ptr = cur->bc_ptrs[0];
3651         block = xfs_btree_get_block(cur, 0, &bp);
3652
3653 #ifdef DEBUG
3654         error = xfs_btree_check_block(cur, block, 0, bp);
3655         if (error)
3656                 return error;
3657 #endif
3658
3659         /*
3660          * Off the right end or left end, return failure.
3661          */
3662         if (ptr > xfs_btree_get_numrecs(block) || ptr <= 0) {
3663                 *stat = 0;
3664                 return 0;
3665         }
3666
3667         /*
3668          * Point to the record and extract its data.
3669          */
3670         *recp = xfs_btree_rec_addr(cur, ptr, block);
3671         *stat = 1;
3672         return 0;
3673 }