Pileus Git - ~andy/linux/blob - fs/xfs/xfs_btree.c

   1 /*
   2  * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include "xfs.h"
  19 #include "xfs_fs.h"
  20 #include "xfs_types.h"
  21 #include "xfs_bit.h"
  22 #include "xfs_log.h"
  23 #include "xfs_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                 bp = cur->bc_bufs[i];
 270                 if (bp) {
 271                         error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
 272                                                    XFS_BUF_ADDR(bp), mp->m_bsize,
 273                                                    0, &bp,
 274                                                    cur->bc_ops->buf_ops);
 275                         if (error) {
 276                                 xfs_btree_del_cursor(new, error);
 277                                 *ncur = NULL;
 278                                 return error;
 279                         }
 280                         new->bc_bufs[i] = bp;
 281                         ASSERT(!xfs_buf_geterror(bp));
 282                 } else
 283                         new->bc_bufs[i] = NULL;
 284         }
 285         *ncur = new;
 286         return 0;
 287 }
 288
 289 /*
 290  * XFS btree block layout and addressing:
 291  *
 292  * There are two types of blocks in the btree: leaf and non-leaf blocks.
 293  *
 294  * The leaf record start with a header then followed by records containing
 295  * the values.  A non-leaf block also starts with the same header, and
 296  * then first contains lookup keys followed by an equal number of pointers
 297  * to the btree blocks at the previous level.
 298  *
 299  *              +--------+-------+-------+-------+-------+-------+-------+
 300  * Leaf:        | header | rec 1 | rec 2 | rec 3 | rec 4 | rec 5 | rec N |
 301  *              +--------+-------+-------+-------+-------+-------+-------+
 302  *
 303  *              +--------+-------+-------+-------+-------+-------+-------+
 304  * Non-Leaf:    | header | key 1 | key 2 | key N | ptr 1 | ptr 2 | ptr N |
 305  *              +--------+-------+-------+-------+-------+-------+-------+
 306  *
 307  * The header is called struct xfs_btree_block for reasons better left unknown
 308  * and comes in different versions for short (32bit) and long (64bit) block
 309  * pointers.  The record and key structures are defined by the btree instances
 310  * and opaque to the btree core.  The block pointers are simple disk endian
 311  * integers, available in a short (32bit) and long (64bit) variant.
 312  *
 313  * The helpers below calculate the offset of a given record, key or pointer
 314  * into a btree block (xfs_btree_*_offset) or return a pointer to the given
 315  * record, key or pointer (xfs_btree_*_addr).  Note that all addressing
 316  * inside the btree block is done using indices starting at one, not zero!
 317  */
 318
 319 /*
 320  * Return size of the btree block header for this btree instance.
 321  */
 322 static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur)
 323 {
 324         return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
 325                 XFS_BTREE_LBLOCK_LEN :
 326                 XFS_BTREE_SBLOCK_LEN;
 327 }
 328
 329 /*
 330  * Return size of btree block pointers for this btree instance.
 331  */
 332 static inline size_t xfs_btree_ptr_len(struct xfs_btree_cur *cur)
 333 {
 334         return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
 335                 sizeof(__be64) : sizeof(__be32);
 336 }
 337
 338 /*
 339  * Calculate offset of the n-th record in a btree block.
 340  */
 341 STATIC size_t
 342 xfs_btree_rec_offset(
 343         struct xfs_btree_cur    *cur,
 344         int                     n)
 345 {
 346         return xfs_btree_block_len(cur) +
 347                 (n - 1) * cur->bc_ops->rec_len;
 348 }
 349
 350 /*
 351  * Calculate offset of the n-th key in a btree block.
 352  */
 353 STATIC size_t
 354 xfs_btree_key_offset(
 355         struct xfs_btree_cur    *cur,
 356         int                     n)
 357 {
 358         return xfs_btree_block_len(cur) +
 359                 (n - 1) * cur->bc_ops->key_len;
 360 }
 361
 362 /*
 363  * Calculate offset of the n-th block pointer in a btree block.
 364  */
 365 STATIC size_t
 366 xfs_btree_ptr_offset(
 367         struct xfs_btree_cur    *cur,
 368         int                     n,
 369         int                     level)
 370 {
 371         return xfs_btree_block_len(cur) +
 372                 cur->bc_ops->get_maxrecs(cur, level) * cur->bc_ops->key_len +
 373                 (n - 1) * xfs_btree_ptr_len(cur);
 374 }
 375
 376 /*
 377  * Return a pointer to the n-th record in the btree block.
 378  */
 379 STATIC union xfs_btree_rec *
 380 xfs_btree_rec_addr(
 381         struct xfs_btree_cur    *cur,
 382         int                     n,
 383         struct xfs_btree_block  *block)
 384 {
 385         return (union xfs_btree_rec *)
 386                 ((char *)block + xfs_btree_rec_offset(cur, n));
 387 }
 388
 389 /*
 390  * Return a pointer to the n-th key in the btree block.
 391  */
 392 STATIC union xfs_btree_key *
 393 xfs_btree_key_addr(
 394         struct xfs_btree_cur    *cur,
 395         int                     n,
 396         struct xfs_btree_block  *block)
 397 {
 398         return (union xfs_btree_key *)
 399                 ((char *)block + xfs_btree_key_offset(cur, n));
 400 }
 401
 402 /*
 403  * Return a pointer to the n-th block pointer in the btree block.
 404  */
 405 STATIC union xfs_btree_ptr *
 406 xfs_btree_ptr_addr(
 407         struct xfs_btree_cur    *cur,
 408         int                     n,
 409         struct xfs_btree_block  *block)
 410 {
 411         int                     level = xfs_btree_get_level(block);
 412
 413         ASSERT(block->bb_level != 0);
 414
 415         return (union xfs_btree_ptr *)
 416                 ((char *)block + xfs_btree_ptr_offset(cur, n, level));
 417 }
 418
 419 /*
 420  * Get a the root block which is stored in the inode.
 421  *
 422  * For now this btree implementation assumes the btree root is always
 423  * stored in the if_broot field of an inode fork.
 424  */
 425 STATIC struct xfs_btree_block *
 426 xfs_btree_get_iroot(
 427        struct xfs_btree_cur    *cur)
 428 {
 429        struct xfs_ifork        *ifp;
 430
 431        ifp = XFS_IFORK_PTR(cur->bc_private.b.ip, cur->bc_private.b.whichfork);
 432        return (struct xfs_btree_block *)ifp->if_broot;
 433 }
 434
 435 /*
 436  * Retrieve the block pointer from the cursor at the given level.
 437  * This may be an inode btree root or from a buffer.
 438  */
 439 STATIC struct xfs_btree_block *         /* generic btree block pointer */
 440 xfs_btree_get_block(
 441         struct xfs_btree_cur    *cur,   /* btree cursor */
 442         int                     level,  /* level in btree */
 443         struct xfs_buf          **bpp)  /* buffer containing the block */
 444 {
 445         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
 446             (level == cur->bc_nlevels - 1)) {
 447                 *bpp = NULL;
 448                 return xfs_btree_get_iroot(cur);
 449         }
 450
 451         *bpp = cur->bc_bufs[level];
 452         return XFS_BUF_TO_BLOCK(*bpp);
 453 }
 454
 455 /*
 456  * Get a buffer for the block, return it with no data read.
 457  * Long-form addressing.
 458  */
 459 xfs_buf_t *                             /* buffer for fsbno */
 460 xfs_btree_get_bufl(
 461         xfs_mount_t     *mp,            /* file system mount point */
 462         xfs_trans_t     *tp,            /* transaction pointer */
 463         xfs_fsblock_t   fsbno,          /* file system block number */
 464         uint            lock)           /* lock flags for get_buf */
 465 {
 466         xfs_buf_t       *bp;            /* buffer pointer (return value) */
 467         xfs_daddr_t             d;              /* real disk block address */
 468
 469         ASSERT(fsbno != NULLFSBLOCK);
 470         d = XFS_FSB_TO_DADDR(mp, fsbno);
 471         bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, lock);
 472         ASSERT(!xfs_buf_geterror(bp));
 473         return bp;
 474 }
 475
 476 /*
 477  * Get a buffer for the block, return it with no data read.
 478  * Short-form addressing.
 479  */
 480 xfs_buf_t *                             /* buffer for agno/agbno */
 481 xfs_btree_get_bufs(
 482         xfs_mount_t     *mp,            /* file system mount point */
 483         xfs_trans_t     *tp,            /* transaction pointer */
 484         xfs_agnumber_t  agno,           /* allocation group number */
 485         xfs_agblock_t   agbno,          /* allocation group block number */
 486         uint            lock)           /* lock flags for get_buf */
 487 {
 488         xfs_buf_t       *bp;            /* buffer pointer (return value) */
 489         xfs_daddr_t             d;              /* real disk block address */
 490
 491         ASSERT(agno != NULLAGNUMBER);
 492         ASSERT(agbno != NULLAGBLOCK);
 493         d = XFS_AGB_TO_DADDR(mp, agno, agbno);
 494         bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, lock);
 495         ASSERT(!xfs_buf_geterror(bp));
 496         return bp;
 497 }
 498
 499 /*
 500  * Check for the cursor referring to the last block at the given level.
 501  */
 502 int                                     /* 1=is last block, 0=not last block */
 503 xfs_btree_islastblock(
 504         xfs_btree_cur_t         *cur,   /* btree cursor */
 505         int                     level)  /* level to check */
 506 {
 507         struct xfs_btree_block  *block; /* generic btree block pointer */
 508         xfs_buf_t               *bp;    /* buffer containing block */
 509
 510         block = xfs_btree_get_block(cur, level, &bp);
 511         xfs_btree_check_block(cur, block, level, bp);
 512         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 513                 return block->bb_u.l.bb_rightsib == cpu_to_be64(NULLDFSBNO);
 514         else
 515                 return block->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK);
 516 }
 517
 518 /*
 519  * Change the cursor to point to the first record at the given level.
 520  * Other levels are unaffected.
 521  */
 522 STATIC int                              /* success=1, failure=0 */
 523 xfs_btree_firstrec(
 524         xfs_btree_cur_t         *cur,   /* btree cursor */
 525         int                     level)  /* level to change */
 526 {
 527         struct xfs_btree_block  *block; /* generic btree block pointer */
 528         xfs_buf_t               *bp;    /* buffer containing block */
 529
 530         /*
 531          * Get the block pointer for this level.
 532          */
 533         block = xfs_btree_get_block(cur, level, &bp);
 534         xfs_btree_check_block(cur, block, level, bp);
 535         /*
 536          * It's empty, there is no such record.
 537          */
 538         if (!block->bb_numrecs)
 539                 return 0;
 540         /*
 541          * Set the ptr value to 1, that's the first record/key.
 542          */
 543         cur->bc_ptrs[level] = 1;
 544         return 1;
 545 }
 546
 547 /*
 548  * Change the cursor to point to the last record in the current block
 549  * at the given level.  Other levels are unaffected.
 550  */
 551 STATIC int                              /* success=1, failure=0 */
 552 xfs_btree_lastrec(
 553         xfs_btree_cur_t         *cur,   /* btree cursor */
 554         int                     level)  /* level to change */
 555 {
 556         struct xfs_btree_block  *block; /* generic btree block pointer */
 557         xfs_buf_t               *bp;    /* buffer containing block */
 558
 559         /*
 560          * Get the block pointer for this level.
 561          */
 562         block = xfs_btree_get_block(cur, level, &bp);
 563         xfs_btree_check_block(cur, block, level, bp);
 564         /*
 565          * It's empty, there is no such record.
 566          */
 567         if (!block->bb_numrecs)
 568                 return 0;
 569         /*
 570          * Set the ptr value to numrecs, that's the last record/key.
 571          */
 572         cur->bc_ptrs[level] = be16_to_cpu(block->bb_numrecs);
 573         return 1;
 574 }
 575
 576 /*
 577  * Compute first and last byte offsets for the fields given.
 578  * Interprets the offsets table, which contains struct field offsets.
 579  */
 580 void
 581 xfs_btree_offsets(
 582         __int64_t       fields,         /* bitmask of fields */
 583         const short     *offsets,       /* table of field offsets */
 584         int             nbits,          /* number of bits to inspect */
 585         int             *first,         /* output: first byte offset */
 586         int             *last)          /* output: last byte offset */
 587 {
 588         int             i;              /* current bit number */
 589         __int64_t       imask;          /* mask for current bit number */
 590
 591         ASSERT(fields != 0);
 592         /*
 593          * Find the lowest bit, so the first byte offset.
 594          */
 595         for (i = 0, imask = 1LL; ; i++, imask <<= 1) {
 596                 if (imask & fields) {
 597                         *first = offsets[i];
 598                         break;
 599                 }
 600         }
 601         /*
 602          * Find the highest bit, so the last byte offset.
 603          */
 604         for (i = nbits - 1, imask = 1LL << i; ; i--, imask >>= 1) {
 605                 if (imask & fields) {
 606                         *last = offsets[i + 1] - 1;
 607                         break;
 608                 }
 609         }
 610 }
 611
 612 /*
 613  * Get a buffer for the block, return it read in.
 614  * Long-form addressing.
 615  */
 616 int
 617 xfs_btree_read_bufl(
 618         struct xfs_mount        *mp,            /* file system mount point */
 619         struct xfs_trans        *tp,            /* transaction pointer */
 620         xfs_fsblock_t           fsbno,          /* file system block number */
 621         uint                    lock,           /* lock flags for read_buf */
 622         struct xfs_buf          **bpp,          /* buffer for fsbno */
 623         int                     refval,         /* ref count value for buffer */
 624         const struct xfs_buf_ops *ops)
 625 {
 626         struct xfs_buf          *bp;            /* return value */
 627         xfs_daddr_t             d;              /* real disk block address */
 628         int                     error;
 629
 630         ASSERT(fsbno != NULLFSBLOCK);
 631         d = XFS_FSB_TO_DADDR(mp, fsbno);
 632         error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
 633                                    mp->m_bsize, lock, &bp, ops);
 634         if (error)
 635                 return error;
 636         ASSERT(!xfs_buf_geterror(bp));
 637         if (bp)
 638                 xfs_buf_set_ref(bp, refval);
 639         *bpp = bp;
 640         return 0;
 641 }
 642
 643 /*
 644  * Read-ahead the block, don't wait for it, don't return a buffer.
 645  * Long-form addressing.
 646  */
 647 /* ARGSUSED */
 648 void
 649 xfs_btree_reada_bufl(
 650         struct xfs_mount        *mp,            /* file system mount point */
 651         xfs_fsblock_t           fsbno,          /* file system block number */
 652         xfs_extlen_t            count,          /* count of filesystem blocks */
 653         const struct xfs_buf_ops *ops)
 654 {
 655         xfs_daddr_t             d;
 656
 657         ASSERT(fsbno != NULLFSBLOCK);
 658         d = XFS_FSB_TO_DADDR(mp, fsbno);
 659         xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count, ops);
 660 }
 661
 662 /*
 663  * Read-ahead the block, don't wait for it, don't return a buffer.
 664  * Short-form addressing.
 665  */
 666 /* ARGSUSED */
 667 void
 668 xfs_btree_reada_bufs(
 669         struct xfs_mount        *mp,            /* file system mount point */
 670         xfs_agnumber_t          agno,           /* allocation group number */
 671         xfs_agblock_t           agbno,          /* allocation group block number */
 672         xfs_extlen_t            count,          /* count of filesystem blocks */
 673         const struct xfs_buf_ops *ops)
 674 {
 675         xfs_daddr_t             d;
 676
 677         ASSERT(agno != NULLAGNUMBER);
 678         ASSERT(agbno != NULLAGBLOCK);
 679         d = XFS_AGB_TO_DADDR(mp, agno, agbno);
 680         xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count, ops);
 681 }
 682
 683 STATIC int
 684 xfs_btree_readahead_lblock(
 685         struct xfs_btree_cur    *cur,
 686         int                     lr,
 687         struct xfs_btree_block  *block)
 688 {
 689         int                     rval = 0;
 690         xfs_dfsbno_t            left = be64_to_cpu(block->bb_u.l.bb_leftsib);
 691         xfs_dfsbno_t            right = be64_to_cpu(block->bb_u.l.bb_rightsib);
 692
 693         if ((lr & XFS_BTCUR_LEFTRA) && left != NULLDFSBNO) {
 694                 xfs_btree_reada_bufl(cur->bc_mp, left, 1,
 695                                      cur->bc_ops->buf_ops);
 696                 rval++;
 697         }
 698
 699         if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLDFSBNO) {
 700                 xfs_btree_reada_bufl(cur->bc_mp, right, 1,
 701                                      cur->bc_ops->buf_ops);
 702                 rval++;
 703         }
 704
 705         return rval;
 706 }
 707
 708 STATIC int
 709 xfs_btree_readahead_sblock(
 710         struct xfs_btree_cur    *cur,
 711         int                     lr,
 712         struct xfs_btree_block *block)
 713 {
 714         int                     rval = 0;
 715         xfs_agblock_t           left = be32_to_cpu(block->bb_u.s.bb_leftsib);
 716         xfs_agblock_t           right = be32_to_cpu(block->bb_u.s.bb_rightsib);
 717
 718
 719         if ((lr & XFS_BTCUR_LEFTRA) && left != NULLAGBLOCK) {
 720                 xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
 721                                      left, 1, cur->bc_ops->buf_ops);
 722                 rval++;
 723         }
 724
 725         if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {
 726                 xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
 727                                      right, 1, cur->bc_ops->buf_ops);
 728                 rval++;
 729         }
 730
 731         return rval;
 732 }
 733
 734 /*
 735  * Read-ahead btree blocks, at the given level.
 736  * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
 737  */
 738 STATIC int
 739 xfs_btree_readahead(
 740         struct xfs_btree_cur    *cur,           /* btree cursor */
 741         int                     lev,            /* level in btree */
 742         int                     lr)             /* left/right bits */
 743 {
 744         struct xfs_btree_block  *block;
 745
 746         /*
 747          * No readahead needed if we are at the root level and the
 748          * btree root is stored in the inode.
 749          */
 750         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
 751             (lev == cur->bc_nlevels - 1))
 752                 return 0;
 753
 754         if ((cur->bc_ra[lev] | lr) == cur->bc_ra[lev])
 755                 return 0;
 756
 757         cur->bc_ra[lev] |= lr;
 758         block = XFS_BUF_TO_BLOCK(cur->bc_bufs[lev]);
 759
 760         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 761                 return xfs_btree_readahead_lblock(cur, lr, block);
 762         return xfs_btree_readahead_sblock(cur, lr, block);
 763 }
 764
 765 /*
 766  * Set the buffer for level "lev" in the cursor to bp, releasing
 767  * any previous buffer.
 768  */
 769 STATIC void
 770 xfs_btree_setbuf(
 771         xfs_btree_cur_t         *cur,   /* btree cursor */
 772         int                     lev,    /* level in btree */
 773         xfs_buf_t               *bp)    /* new buffer to set */
 774 {
 775         struct xfs_btree_block  *b;     /* btree block */
 776
 777         if (cur->bc_bufs[lev])
 778                 xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[lev]);
 779         cur->bc_bufs[lev] = bp;
 780         cur->bc_ra[lev] = 0;
 781
 782         b = XFS_BUF_TO_BLOCK(bp);
 783         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 784                 if (b->bb_u.l.bb_leftsib == cpu_to_be64(NULLDFSBNO))
 785                         cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
 786                 if (b->bb_u.l.bb_rightsib == cpu_to_be64(NULLDFSBNO))
 787                         cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
 788         } else {
 789                 if (b->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK))
 790                         cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
 791                 if (b->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK))
 792                         cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
 793         }
 794 }
 795
 796 STATIC int
 797 xfs_btree_ptr_is_null(
 798         struct xfs_btree_cur    *cur,
 799         union xfs_btree_ptr     *ptr)
 800 {
 801         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 802                 return ptr->l == cpu_to_be64(NULLDFSBNO);
 803         else
 804                 return ptr->s == cpu_to_be32(NULLAGBLOCK);
 805 }
 806
 807 STATIC void
 808 xfs_btree_set_ptr_null(
 809         struct xfs_btree_cur    *cur,
 810         union xfs_btree_ptr     *ptr)
 811 {
 812         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 813                 ptr->l = cpu_to_be64(NULLDFSBNO);
 814         else
 815                 ptr->s = cpu_to_be32(NULLAGBLOCK);
 816 }
 817
 818 /*
 819  * Get/set/init sibling pointers
 820  */
 821 STATIC void
 822 xfs_btree_get_sibling(
 823         struct xfs_btree_cur    *cur,
 824         struct xfs_btree_block  *block,
 825         union xfs_btree_ptr     *ptr,
 826         int                     lr)
 827 {
 828         ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
 829
 830         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 831                 if (lr == XFS_BB_RIGHTSIB)
 832                         ptr->l = block->bb_u.l.bb_rightsib;
 833                 else
 834                         ptr->l = block->bb_u.l.bb_leftsib;
 835         } else {
 836                 if (lr == XFS_BB_RIGHTSIB)
 837                         ptr->s = block->bb_u.s.bb_rightsib;
 838                 else
 839                         ptr->s = block->bb_u.s.bb_leftsib;
 840         }
 841 }
 842
 843 STATIC void
 844 xfs_btree_set_sibling(
 845         struct xfs_btree_cur    *cur,
 846         struct xfs_btree_block  *block,
 847         union xfs_btree_ptr     *ptr,
 848         int                     lr)
 849 {
 850         ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
 851
 852         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 853                 if (lr == XFS_BB_RIGHTSIB)
 854                         block->bb_u.l.bb_rightsib = ptr->l;
 855                 else
 856                         block->bb_u.l.bb_leftsib = ptr->l;
 857         } else {
 858                 if (lr == XFS_BB_RIGHTSIB)
 859                         block->bb_u.s.bb_rightsib = ptr->s;
 860                 else
 861                         block->bb_u.s.bb_leftsib = ptr->s;
 862         }
 863 }
 864
 865 void
 866 xfs_btree_init_block(
 867         struct xfs_mount *mp,
 868         struct xfs_buf  *bp,
 869         __u32           magic,
 870         __u16           level,
 871         __u16           numrecs,
 872         unsigned int    flags)
 873 {
 874         struct xfs_btree_block  *new = XFS_BUF_TO_BLOCK(bp);
 875
 876         new->bb_magic = cpu_to_be32(magic);
 877         new->bb_level = cpu_to_be16(level);
 878         new->bb_numrecs = cpu_to_be16(numrecs);
 879
 880         if (flags & XFS_BTREE_LONG_PTRS) {
 881                 new->bb_u.l.bb_leftsib = cpu_to_be64(NULLDFSBNO);
 882                 new->bb_u.l.bb_rightsib = cpu_to_be64(NULLDFSBNO);
 883         } else {
 884                 new->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
 885                 new->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
 886         }
 887 }
 888
 889 STATIC void
 890 xfs_btree_init_block_cur(
 891         struct xfs_btree_cur    *cur,
 892         int                     level,
 893         int                     numrecs,
 894         struct xfs_buf          *bp)
 895 {
 896         xfs_btree_init_block(cur->bc_mp, bp, xfs_magics[cur->bc_btnum],
 897                                level, numrecs, cur->bc_flags);
 898 }
 899
 900 /*
 901  * Return true if ptr is the last record in the btree and
 902  * we need to track updateѕ to this record.  The decision
 903  * will be further refined in the update_lastrec method.
 904  */
 905 STATIC int
 906 xfs_btree_is_lastrec(
 907         struct xfs_btree_cur    *cur,
 908         struct xfs_btree_block  *block,
 909         int                     level)
 910 {
 911         union xfs_btree_ptr     ptr;
 912
 913         if (level > 0)
 914                 return 0;
 915         if (!(cur->bc_flags & XFS_BTREE_LASTREC_UPDATE))
 916                 return 0;
 917
 918         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
 919         if (!xfs_btree_ptr_is_null(cur, &ptr))
 920                 return 0;
 921         return 1;
 922 }
 923
 924 STATIC void
 925 xfs_btree_buf_to_ptr(
 926         struct xfs_btree_cur    *cur,
 927         struct xfs_buf          *bp,
 928         union xfs_btree_ptr     *ptr)
 929 {
 930         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 931                 ptr->l = cpu_to_be64(XFS_DADDR_TO_FSB(cur->bc_mp,
 932                                         XFS_BUF_ADDR(bp)));
 933         else {
 934                 ptr->s = cpu_to_be32(xfs_daddr_to_agbno(cur->bc_mp,
 935                                         XFS_BUF_ADDR(bp)));
 936         }
 937 }
 938
 939 STATIC xfs_daddr_t
 940 xfs_btree_ptr_to_daddr(
 941         struct xfs_btree_cur    *cur,
 942         union xfs_btree_ptr     *ptr)
 943 {
 944         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 945                 ASSERT(ptr->l != cpu_to_be64(NULLDFSBNO));
 946
 947                 return XFS_FSB_TO_DADDR(cur->bc_mp, be64_to_cpu(ptr->l));
 948         } else {
 949                 ASSERT(cur->bc_private.a.agno != NULLAGNUMBER);
 950                 ASSERT(ptr->s != cpu_to_be32(NULLAGBLOCK));
 951
 952                 return XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_private.a.agno,
 953                                         be32_to_cpu(ptr->s));
 954         }
 955 }
 956
 957 STATIC void
 958 xfs_btree_set_refs(
 959         struct xfs_btree_cur    *cur,
 960         struct xfs_buf          *bp)
 961 {
 962         switch (cur->bc_btnum) {
 963         case XFS_BTNUM_BNO:
 964         case XFS_BTNUM_CNT:
 965                 xfs_buf_set_ref(bp, XFS_ALLOC_BTREE_REF);
 966                 break;
 967         case XFS_BTNUM_INO:
 968                 xfs_buf_set_ref(bp, XFS_INO_BTREE_REF);
 969                 break;
 970         case XFS_BTNUM_BMAP:
 971                 xfs_buf_set_ref(bp, XFS_BMAP_BTREE_REF);
 972                 break;
 973         default:
 974                 ASSERT(0);
 975         }
 976 }
 977
 978 STATIC int
 979 xfs_btree_get_buf_block(
 980         struct xfs_btree_cur    *cur,
 981         union xfs_btree_ptr     *ptr,
 982         int                     flags,
 983         struct xfs_btree_block  **block,
 984         struct xfs_buf          **bpp)
 985 {
 986         struct xfs_mount        *mp = cur->bc_mp;
 987         xfs_daddr_t             d;
 988
 989         /* need to sort out how callers deal with failures first */
 990         ASSERT(!(flags & XBF_TRYLOCK));
 991
 992         d = xfs_btree_ptr_to_daddr(cur, ptr);
 993         *bpp = xfs_trans_get_buf(cur->bc_tp, mp->m_ddev_targp, d,
 994                                  mp->m_bsize, flags);
 995
 996         if (!*bpp)
 997                 return ENOMEM;
 998
 999         (*bpp)->b_ops = cur->bc_ops->buf_ops;
1000         *block = XFS_BUF_TO_BLOCK(*bpp);
1001         return 0;
1002 }
1003
1004 /*
1005  * Read in the buffer at the given ptr and return the buffer and
1006  * the block pointer within the buffer.
1007  */
1008 STATIC int
1009 xfs_btree_read_buf_block(
1010         struct xfs_btree_cur    *cur,
1011         union xfs_btree_ptr     *ptr,
1012         int                     level,
1013         int                     flags,
1014         struct xfs_btree_block  **block,
1015         struct xfs_buf          **bpp)
1016 {
1017         struct xfs_mount        *mp = cur->bc_mp;
1018         xfs_daddr_t             d;
1019         int                     error;
1020
1021         /* need to sort out how callers deal with failures first */
1022         ASSERT(!(flags & XBF_TRYLOCK));
1023
1024         d = xfs_btree_ptr_to_daddr(cur, ptr);
1025         error = xfs_trans_read_buf(mp, cur->bc_tp, mp->m_ddev_targp, d,
1026                                    mp->m_bsize, flags, bpp,
1027                                    cur->bc_ops->buf_ops);
1028         if (error)
1029                 return error;
1030
1031         ASSERT(!xfs_buf_geterror(*bpp));
1032         xfs_btree_set_refs(cur, *bpp);
1033         *block = XFS_BUF_TO_BLOCK(*bpp);
1034         return 0;
1035 }
1036
1037 /*
1038  * Copy keys from one btree block to another.
1039  */
1040 STATIC void
1041 xfs_btree_copy_keys(
1042         struct xfs_btree_cur    *cur,
1043         union xfs_btree_key     *dst_key,
1044         union xfs_btree_key     *src_key,
1045         int                     numkeys)
1046 {
1047         ASSERT(numkeys >= 0);
1048         memcpy(dst_key, src_key, numkeys * cur->bc_ops->key_len);
1049 }
1050
1051 /*
1052  * Copy records from one btree block to another.
1053  */
1054 STATIC void
1055 xfs_btree_copy_recs(
1056         struct xfs_btree_cur    *cur,
1057         union xfs_btree_rec     *dst_rec,
1058         union xfs_btree_rec     *src_rec,
1059         int                     numrecs)
1060 {
1061         ASSERT(numrecs >= 0);
1062         memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
1063 }
1064
1065 /*
1066  * Copy block pointers from one btree block to another.
1067  */
1068 STATIC void
1069 xfs_btree_copy_ptrs(
1070         struct xfs_btree_cur    *cur,
1071         union xfs_btree_ptr     *dst_ptr,
1072         union xfs_btree_ptr     *src_ptr,
1073         int                     numptrs)
1074 {
1075         ASSERT(numptrs >= 0);
1076         memcpy(dst_ptr, src_ptr, numptrs * xfs_btree_ptr_len(cur));
1077 }
1078
1079 /*
1080  * Shift keys one index left/right inside a single btree block.
1081  */
1082 STATIC void
1083 xfs_btree_shift_keys(
1084         struct xfs_btree_cur    *cur,
1085         union xfs_btree_key     *key,
1086         int                     dir,
1087         int                     numkeys)
1088 {
1089         char                    *dst_key;
1090
1091         ASSERT(numkeys >= 0);
1092         ASSERT(dir == 1 || dir == -1);
1093
1094         dst_key = (char *)key + (dir * cur->bc_ops->key_len);
1095         memmove(dst_key, key, numkeys * cur->bc_ops->key_len);
1096 }
1097
1098 /*
1099  * Shift records one index left/right inside a single btree block.
1100  */
1101 STATIC void
1102 xfs_btree_shift_recs(
1103         struct xfs_btree_cur    *cur,
1104         union xfs_btree_rec     *rec,
1105         int                     dir,
1106         int                     numrecs)
1107 {
1108         char                    *dst_rec;
1109
1110         ASSERT(numrecs >= 0);
1111         ASSERT(dir == 1 || dir == -1);
1112
1113         dst_rec = (char *)rec + (dir * cur->bc_ops->rec_len);
1114         memmove(dst_rec, rec, numrecs * cur->bc_ops->rec_len);
1115 }
1116
1117 /*
1118  * Shift block pointers one index left/right inside a single btree block.
1119  */
1120 STATIC void
1121 xfs_btree_shift_ptrs(
1122         struct xfs_btree_cur    *cur,
1123         union xfs_btree_ptr     *ptr,
1124         int                     dir,
1125         int                     numptrs)
1126 {
1127         char                    *dst_ptr;
1128
1129         ASSERT(numptrs >= 0);
1130         ASSERT(dir == 1 || dir == -1);
1131
1132         dst_ptr = (char *)ptr + (dir * xfs_btree_ptr_len(cur));
1133         memmove(dst_ptr, ptr, numptrs * xfs_btree_ptr_len(cur));
1134 }
1135
1136 /*
1137  * Log key values from the btree block.
1138  */
1139 STATIC void
1140 xfs_btree_log_keys(
1141         struct xfs_btree_cur    *cur,
1142         struct xfs_buf          *bp,
1143         int                     first,
1144         int                     last)
1145 {
1146         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1147         XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
1148
1149         if (bp) {
1150                 xfs_trans_log_buf(cur->bc_tp, bp,
1151                                   xfs_btree_key_offset(cur, first),
1152                                   xfs_btree_key_offset(cur, last + 1) - 1);
1153         } else {
1154                 xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1155                                 xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1156         }
1157
1158         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1159 }
1160
1161 /*
1162  * Log record values from the btree block.
1163  */
1164 void
1165 xfs_btree_log_recs(
1166         struct xfs_btree_cur    *cur,
1167         struct xfs_buf          *bp,
1168         int                     first,
1169         int                     last)
1170 {
1171         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1172         XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
1173
1174         xfs_trans_log_buf(cur->bc_tp, bp,
1175                           xfs_btree_rec_offset(cur, first),
1176                           xfs_btree_rec_offset(cur, last + 1) - 1);
1177
1178         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1179 }
1180
1181 /*
1182  * Log block pointer fields from a btree block (nonleaf).
1183  */
1184 STATIC void
1185 xfs_btree_log_ptrs(
1186         struct xfs_btree_cur    *cur,   /* btree cursor */
1187         struct xfs_buf          *bp,    /* buffer containing btree block */
1188         int                     first,  /* index of first pointer to log */
1189         int                     last)   /* index of last pointer to log */
1190 {
1191         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1192         XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
1193
1194         if (bp) {
1195                 struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
1196                 int                     level = xfs_btree_get_level(block);
1197
1198                 xfs_trans_log_buf(cur->bc_tp, bp,
1199                                 xfs_btree_ptr_offset(cur, first, level),
1200                                 xfs_btree_ptr_offset(cur, last + 1, level) - 1);
1201         } else {
1202                 xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1203                         xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1204         }
1205
1206         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1207 }
1208
1209 /*
1210  * Log fields from a btree block header.
1211  */
1212 void
1213 xfs_btree_log_block(
1214         struct xfs_btree_cur    *cur,   /* btree cursor */
1215         struct xfs_buf          *bp,    /* buffer containing btree block */
1216         int                     fields) /* mask of fields: XFS_BB_... */
1217 {
1218         int                     first;  /* first byte offset logged */
1219         int                     last;   /* last byte offset logged */
1220         static const short      soffsets[] = {  /* table of offsets (short) */
1221                 offsetof(struct xfs_btree_block, bb_magic),
1222                 offsetof(struct xfs_btree_block, bb_level),
1223                 offsetof(struct xfs_btree_block, bb_numrecs),
1224                 offsetof(struct xfs_btree_block, bb_u.s.bb_leftsib),
1225                 offsetof(struct xfs_btree_block, bb_u.s.bb_rightsib),
1226                 XFS_BTREE_SBLOCK_LEN
1227         };
1228         static const short      loffsets[] = {  /* table of offsets (long) */
1229                 offsetof(struct xfs_btree_block, bb_magic),
1230                 offsetof(struct xfs_btree_block, bb_level),
1231                 offsetof(struct xfs_btree_block, bb_numrecs),
1232                 offsetof(struct xfs_btree_block, bb_u.l.bb_leftsib),
1233                 offsetof(struct xfs_btree_block, bb_u.l.bb_rightsib),
1234                 XFS_BTREE_LBLOCK_LEN
1235         };
1236
1237         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1238         XFS_BTREE_TRACE_ARGBI(cur, bp, fields);
1239
1240         if (bp) {
1241                 xfs_btree_offsets(fields,
1242                                   (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
1243                                         loffsets : soffsets,
1244                                   XFS_BB_NUM_BITS, &first, &last);
1245                 xfs_trans_log_buf(cur->bc_tp, bp, first, last);
1246         } else {
1247                 xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1248                         xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1249         }
1250
1251         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1252 }
1253
1254 /*
1255  * Increment cursor by one record at the level.
1256  * For nonzero levels the leaf-ward information is untouched.
1257  */
1258 int                                             /* error */
1259 xfs_btree_increment(
1260         struct xfs_btree_cur    *cur,
1261         int                     level,
1262         int                     *stat)          /* success/failure */
1263 {
1264         struct xfs_btree_block  *block;
1265         union xfs_btree_ptr     ptr;
1266         struct xfs_buf          *bp;
1267         int                     error;          /* error return value */
1268         int                     lev;
1269
1270         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1271         XFS_BTREE_TRACE_ARGI(cur, level);
1272
1273         ASSERT(level < cur->bc_nlevels);
1274
1275         /* Read-ahead to the right at this level. */
1276         xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
1277
1278         /* Get a pointer to the btree block. */
1279         block = xfs_btree_get_block(cur, level, &bp);
1280
1281 #ifdef DEBUG
1282         error = xfs_btree_check_block(cur, block, level, bp);
1283         if (error)
1284                 goto error0;
1285 #endif
1286
1287         /* We're done if we remain in the block after the increment. */
1288         if (++cur->bc_ptrs[level] <= xfs_btree_get_numrecs(block))
1289                 goto out1;
1290
1291         /* Fail if we just went off the right edge of the tree. */
1292         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1293         if (xfs_btree_ptr_is_null(cur, &ptr))
1294                 goto out0;
1295
1296         XFS_BTREE_STATS_INC(cur, increment);
1297
1298         /*
1299          * March up the tree incrementing pointers.
1300          * Stop when we don't go off the right edge of a block.
1301          */
1302         for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1303                 block = xfs_btree_get_block(cur, lev, &bp);
1304
1305 #ifdef DEBUG
1306                 error = xfs_btree_check_block(cur, block, lev, bp);
1307                 if (error)
1308                         goto error0;
1309 #endif
1310
1311                 if (++cur->bc_ptrs[lev] <= xfs_btree_get_numrecs(block))
1312                         break;
1313
1314                 /* Read-ahead the right block for the next loop. */
1315                 xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);
1316         }
1317
1318         /*
1319          * If we went off the root then we are either seriously
1320          * confused or have the tree root in an inode.
1321          */
1322         if (lev == cur->bc_nlevels) {
1323                 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1324                         goto out0;
1325                 ASSERT(0);
1326                 error = EFSCORRUPTED;
1327                 goto error0;
1328         }
1329         ASSERT(lev < cur->bc_nlevels);
1330
1331         /*
1332          * Now walk back down the tree, fixing up the cursor's buffer
1333          * pointers and key numbers.
1334          */
1335         for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1336                 union xfs_btree_ptr     *ptrp;
1337
1338                 ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
1339                 error = xfs_btree_read_buf_block(cur, ptrp, --lev,
1340                                                         0, &block, &bp);
1341                 if (error)
1342                         goto error0;
1343
1344                 xfs_btree_setbuf(cur, lev, bp);
1345                 cur->bc_ptrs[lev] = 1;
1346         }
1347 out1:
1348         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1349         *stat = 1;
1350         return 0;
1351
1352 out0:
1353         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1354         *stat = 0;
1355         return 0;
1356
1357 error0:
1358         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1359         return error;
1360 }
1361
1362 /*
1363  * Decrement cursor by one record at the level.
1364  * For nonzero levels the leaf-ward information is untouched.
1365  */
1366 int                                             /* error */
1367 xfs_btree_decrement(
1368         struct xfs_btree_cur    *cur,
1369         int                     level,
1370         int                     *stat)          /* success/failure */
1371 {
1372         struct xfs_btree_block  *block;
1373         xfs_buf_t               *bp;
1374         int                     error;          /* error return value */
1375         int                     lev;
1376         union xfs_btree_ptr     ptr;
1377
1378         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1379         XFS_BTREE_TRACE_ARGI(cur, level);
1380
1381         ASSERT(level < cur->bc_nlevels);
1382
1383         /* Read-ahead to the left at this level. */
1384         xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);
1385
1386         /* We're done if we remain in the block after the decrement. */
1387         if (--cur->bc_ptrs[level] > 0)
1388                 goto out1;
1389
1390         /* Get a pointer to the btree block. */
1391         block = xfs_btree_get_block(cur, level, &bp);
1392
1393 #ifdef DEBUG
1394         error = xfs_btree_check_block(cur, block, level, bp);
1395         if (error)
1396                 goto error0;
1397 #endif
1398
1399         /* Fail if we just went off the left edge of the tree. */
1400         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
1401         if (xfs_btree_ptr_is_null(cur, &ptr))
1402                 goto out0;
1403
1404         XFS_BTREE_STATS_INC(cur, decrement);
1405
1406         /*
1407          * March up the tree decrementing pointers.
1408          * Stop when we don't go off the left edge of a block.
1409          */
1410         for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1411                 if (--cur->bc_ptrs[lev] > 0)
1412                         break;
1413                 /* Read-ahead the left block for the next loop. */
1414                 xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);
1415         }
1416
1417         /*
1418          * If we went off the root then we are seriously confused.
1419          * or the root of the tree is in an inode.
1420          */
1421         if (lev == cur->bc_nlevels) {
1422                 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1423                         goto out0;
1424                 ASSERT(0);
1425                 error = EFSCORRUPTED;
1426                 goto error0;
1427         }
1428         ASSERT(lev < cur->bc_nlevels);
1429
1430         /*
1431          * Now walk back down the tree, fixing up the cursor's buffer
1432          * pointers and key numbers.
1433          */
1434         for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1435                 union xfs_btree_ptr     *ptrp;
1436
1437                 ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
1438                 error = xfs_btree_read_buf_block(cur, ptrp, --lev,
1439                                                         0, &block, &bp);
1440                 if (error)
1441                         goto error0;
1442                 xfs_btree_setbuf(cur, lev, bp);
1443                 cur->bc_ptrs[lev] = xfs_btree_get_numrecs(block);
1444         }
1445 out1:
1446         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1447         *stat = 1;
1448         return 0;
1449
1450 out0:
1451         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1452         *stat = 0;
1453         return 0;
1454
1455 error0:
1456         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1457         return error;
1458 }
1459
1460 STATIC int
1461 xfs_btree_lookup_get_block(
1462         struct xfs_btree_cur    *cur,   /* btree cursor */
1463         int                     level,  /* level in the btree */
1464         union xfs_btree_ptr     *pp,    /* ptr to btree block */
1465         struct xfs_btree_block  **blkp) /* return btree block */
1466 {
1467         struct xfs_buf          *bp;    /* buffer pointer for btree block */
1468         int                     error = 0;
1469
1470         /* special case the root block if in an inode */
1471         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1472             (level == cur->bc_nlevels - 1)) {
1473                 *blkp = xfs_btree_get_iroot(cur);
1474                 return 0;
1475         }
1476
1477         /*
1478          * If the old buffer at this level for the disk address we are
1479          * looking for re-use it.
1480          *
1481          * Otherwise throw it away and get a new one.
1482          */
1483         bp = cur->bc_bufs[level];
1484         if (bp && XFS_BUF_ADDR(bp) == xfs_btree_ptr_to_daddr(cur, pp)) {
1485                 *blkp = XFS_BUF_TO_BLOCK(bp);
1486                 return 0;
1487         }
1488
1489         error = xfs_btree_read_buf_block(cur, pp, level, 0, blkp, &bp);
1490         if (error)
1491                 return error;
1492
1493         xfs_btree_setbuf(cur, level, bp);
1494         return 0;
1495 }
1496
1497 /*
1498  * Get current search key.  For level 0 we don't actually have a key
1499  * structure so we make one up from the record.  For all other levels
1500  * we just return the right key.
1501  */
1502 STATIC union xfs_btree_key *
1503 xfs_lookup_get_search_key(
1504         struct xfs_btree_cur    *cur,
1505         int                     level,
1506         int                     keyno,
1507         struct xfs_btree_block  *block,
1508         union xfs_btree_key     *kp)
1509 {
1510         if (level == 0) {
1511                 cur->bc_ops->init_key_from_rec(kp,
1512                                 xfs_btree_rec_addr(cur, keyno, block));
1513                 return kp;
1514         }
1515
1516         return xfs_btree_key_addr(cur, keyno, block);
1517 }
1518
1519 /*
1520  * Lookup the record.  The cursor is made to point to it, based on dir.
1521  * Return 0 if can't find any such record, 1 for success.
1522  */
1523 int                                     /* error */
1524 xfs_btree_lookup(
1525         struct xfs_btree_cur    *cur,   /* btree cursor */
1526         xfs_lookup_t            dir,    /* <=, ==, or >= */
1527         int                     *stat)  /* success/failure */
1528 {
1529         struct xfs_btree_block  *block; /* current btree block */
1530         __int64_t               diff;   /* difference for the current key */
1531         int                     error;  /* error return value */
1532         int                     keyno;  /* current key number */
1533         int                     level;  /* level in the btree */
1534         union xfs_btree_ptr     *pp;    /* ptr to btree block */
1535         union xfs_btree_ptr     ptr;    /* ptr to btree block */
1536
1537         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1538         XFS_BTREE_TRACE_ARGI(cur, dir);
1539
1540         XFS_BTREE_STATS_INC(cur, lookup);
1541
1542         block = NULL;
1543         keyno = 0;
1544
1545         /* initialise start pointer from cursor */
1546         cur->bc_ops->init_ptr_from_cur(cur, &ptr);
1547         pp = &ptr;
1548
1549         /*
1550          * Iterate over each level in the btree, starting at the root.
1551          * For each level above the leaves, find the key we need, based
1552          * on the lookup record, then follow the corresponding block
1553          * pointer down to the next level.
1554          */
1555         for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {
1556                 /* Get the block we need to do the lookup on. */
1557                 error = xfs_btree_lookup_get_block(cur, level, pp, &block);
1558                 if (error)
1559                         goto error0;
1560
1561                 if (diff == 0) {
1562                         /*
1563                          * If we already had a key match at a higher level, we
1564                          * know we need to use the first entry in this block.
1565                          */
1566                         keyno = 1;
1567                 } else {
1568                         /* Otherwise search this block. Do a binary search. */
1569
1570                         int     high;   /* high entry number */
1571                         int     low;    /* low entry number */
1572
1573                         /* Set low and high entry numbers, 1-based. */
1574                         low = 1;
1575                         high = xfs_btree_get_numrecs(block);
1576                         if (!high) {
1577                                 /* Block is empty, must be an empty leaf. */
1578                                 ASSERT(level == 0 && cur->bc_nlevels == 1);
1579
1580                                 cur->bc_ptrs[0] = dir != XFS_LOOKUP_LE;
1581                                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1582                                 *stat = 0;
1583                                 return 0;
1584                         }
1585
1586                         /* Binary search the block. */
1587                         while (low <= high) {
1588                                 union xfs_btree_key     key;
1589                                 union xfs_btree_key     *kp;
1590
1591                                 XFS_BTREE_STATS_INC(cur, compare);
1592
1593                                 /* keyno is average of low and high. */
1594                                 keyno = (low + high) >> 1;
1595
1596                                 /* Get current search key */
1597                                 kp = xfs_lookup_get_search_key(cur, level,
1598                                                 keyno, block, &key);
1599
1600                                 /*
1601                                  * Compute difference to get next direction:
1602                                  *  - less than, move right
1603                                  *  - greater than, move left
1604                                  *  - equal, we're done
1605                                  */
1606                                 diff = cur->bc_ops->key_diff(cur, kp);
1607                                 if (diff < 0)
1608                                         low = keyno + 1;
1609                                 else if (diff > 0)
1610                                         high = keyno - 1;
1611                                 else
1612                                         break;
1613                         }
1614                 }
1615
1616                 /*
1617                  * If there are more levels, set up for the next level
1618                  * by getting the block number and filling in the cursor.
1619                  */
1620                 if (level > 0) {
1621                         /*
1622                          * If we moved left, need the previous key number,
1623                          * unless there isn't one.
1624                          */
1625                         if (diff > 0 && --keyno < 1)
1626                                 keyno = 1;
1627                         pp = xfs_btree_ptr_addr(cur, keyno, block);
1628
1629 #ifdef DEBUG
1630                         error = xfs_btree_check_ptr(cur, pp, 0, level);
1631                         if (error)
1632                                 goto error0;
1633 #endif
1634                         cur->bc_ptrs[level] = keyno;
1635                 }
1636         }
1637
1638         /* Done with the search. See if we need to adjust the results. */
1639         if (dir != XFS_LOOKUP_LE && diff < 0) {
1640                 keyno++;
1641                 /*
1642                  * If ge search and we went off the end of the block, but it's
1643                  * not the last block, we're in the wrong block.
1644                  */
1645                 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1646                 if (dir == XFS_LOOKUP_GE &&
1647                     keyno > xfs_btree_get_numrecs(block) &&
1648                     !xfs_btree_ptr_is_null(cur, &ptr)) {
1649                         int     i;
1650
1651                         cur->bc_ptrs[0] = keyno;
1652                         error = xfs_btree_increment(cur, 0, &i);
1653                         if (error)
1654                                 goto error0;
1655                         XFS_WANT_CORRUPTED_RETURN(i == 1);
1656                         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1657                         *stat = 1;
1658                         return 0;
1659                 }
1660         } else if (dir == XFS_LOOKUP_LE && diff > 0)
1661                 keyno--;
1662         cur->bc_ptrs[0] = keyno;
1663
1664         /* Return if we succeeded or not. */
1665         if (keyno == 0 || keyno > xfs_btree_get_numrecs(block))
1666                 *stat = 0;
1667         else if (dir != XFS_LOOKUP_EQ || diff == 0)
1668                 *stat = 1;
1669         else
1670                 *stat = 0;
1671         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1672         return 0;
1673
1674 error0:
1675         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1676         return error;
1677 }
1678
1679 /*
1680  * Update keys at all levels from here to the root along the cursor's path.
1681  */
1682 STATIC int
1683 xfs_btree_updkey(
1684         struct xfs_btree_cur    *cur,
1685         union xfs_btree_key     *keyp,
1686         int                     level)
1687 {
1688         struct xfs_btree_block  *block;
1689         struct xfs_buf          *bp;
1690         union xfs_btree_key     *kp;
1691         int                     ptr;
1692
1693         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1694         XFS_BTREE_TRACE_ARGIK(cur, level, keyp);
1695
1696         ASSERT(!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) || level >= 1);
1697
1698         /*
1699          * Go up the tree from this level toward the root.
1700          * At each level, update the key value to the value input.
1701          * Stop when we reach a level where the cursor isn't pointing
1702          * at the first entry in the block.
1703          */
1704         for (ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
1705 #ifdef DEBUG
1706                 int             error;
1707 #endif
1708                 block = xfs_btree_get_block(cur, level, &bp);
1709 #ifdef DEBUG
1710                 error = xfs_btree_check_block(cur, block, level, bp);
1711                 if (error) {
1712                         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1713                         return error;
1714                 }
1715 #endif
1716                 ptr = cur->bc_ptrs[level];
1717                 kp = xfs_btree_key_addr(cur, ptr, block);
1718                 xfs_btree_copy_keys(cur, kp, keyp, 1);
1719                 xfs_btree_log_keys(cur, bp, ptr, ptr);
1720         }
1721
1722         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1723         return 0;
1724 }
1725
1726 /*
1727  * Update the record referred to by cur to the value in the
1728  * given record. This either works (return 0) or gets an
1729  * EFSCORRUPTED error.
1730  */
1731 int
1732 xfs_btree_update(
1733         struct xfs_btree_cur    *cur,
1734         union xfs_btree_rec     *rec)
1735 {
1736         struct xfs_btree_block  *block;
1737         struct xfs_buf          *bp;
1738         int                     error;
1739         int                     ptr;
1740         union xfs_btree_rec     *rp;
1741
1742         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1743         XFS_BTREE_TRACE_ARGR(cur, rec);
1744
1745         /* Pick up the current block. */
1746         block = xfs_btree_get_block(cur, 0, &bp);
1747
1748 #ifdef DEBUG
1749         error = xfs_btree_check_block(cur, block, 0, bp);
1750         if (error)
1751                 goto error0;
1752 #endif
1753         /* Get the address of the rec to be updated. */
1754         ptr = cur->bc_ptrs[0];
1755         rp = xfs_btree_rec_addr(cur, ptr, block);
1756
1757         /* Fill in the new contents and log them. */
1758         xfs_btree_copy_recs(cur, rp, rec, 1);
1759         xfs_btree_log_recs(cur, bp, ptr, ptr);
1760
1761         /*
1762          * If we are tracking the last record in the tree and
1763          * we are at the far right edge of the tree, update it.
1764          */
1765         if (xfs_btree_is_lastrec(cur, block, 0)) {
1766                 cur->bc_ops->update_lastrec(cur, block, rec,
1767                                             ptr, LASTREC_UPDATE);
1768         }
1769
1770         /* Updating first rec in leaf. Pass new key value up to our parent. */
1771         if (ptr == 1) {
1772                 union xfs_btree_key     key;
1773
1774                 cur->bc_ops->init_key_from_rec(&key, rec);
1775                 error = xfs_btree_updkey(cur, &key, 1);
1776                 if (error)
1777                         goto error0;
1778         }
1779
1780         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1781         return 0;
1782
1783 error0:
1784         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1785         return error;
1786 }
1787
1788 /*
1789  * Move 1 record left from cur/level if possible.
1790  * Update cur to reflect the new path.
1791  */
1792 STATIC int                                      /* error */
1793 xfs_btree_lshift(
1794         struct xfs_btree_cur    *cur,
1795         int                     level,
1796         int                     *stat)          /* success/failure */
1797 {
1798         union xfs_btree_key     key;            /* btree key */
1799         struct xfs_buf          *lbp;           /* left buffer pointer */
1800         struct xfs_btree_block  *left;          /* left btree block */
1801         int                     lrecs;          /* left record count */
1802         struct xfs_buf          *rbp;           /* right buffer pointer */
1803         struct xfs_btree_block  *right;         /* right btree block */
1804         int                     rrecs;          /* right record count */
1805         union xfs_btree_ptr     lptr;           /* left btree pointer */
1806         union xfs_btree_key     *rkp = NULL;    /* right btree key */
1807         union xfs_btree_ptr     *rpp = NULL;    /* right address pointer */
1808         union xfs_btree_rec     *rrp = NULL;    /* right record pointer */
1809         int                     error;          /* error return value */
1810
1811         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1812         XFS_BTREE_TRACE_ARGI(cur, level);
1813
1814         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1815             level == cur->bc_nlevels - 1)
1816                 goto out0;
1817
1818         /* Set up variables for this block as "right". */
1819         right = xfs_btree_get_block(cur, level, &rbp);
1820
1821 #ifdef DEBUG
1822         error = xfs_btree_check_block(cur, right, level, rbp);
1823         if (error)
1824                 goto error0;
1825 #endif
1826
1827         /* If we've got no left sibling then we can't shift an entry left. */
1828         xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
1829         if (xfs_btree_ptr_is_null(cur, &lptr))
1830                 goto out0;
1831
1832         /*
1833          * If the cursor entry is the one that would be moved, don't
1834          * do it... it's too complicated.
1835          */
1836         if (cur->bc_ptrs[level] <= 1)
1837                 goto out0;
1838
1839         /* Set up the left neighbor as "left". */
1840         error = xfs_btree_read_buf_block(cur, &lptr, level, 0, &left, &lbp);
1841         if (error)
1842                 goto error0;
1843
1844         /* If it's full, it can't take another entry. */
1845         lrecs = xfs_btree_get_numrecs(left);
1846         if (lrecs == cur->bc_ops->get_maxrecs(cur, level))
1847                 goto out0;
1848
1849         rrecs = xfs_btree_get_numrecs(right);
1850
1851         /*
1852          * We add one entry to the left side and remove one for the right side.
1853          * Account for it here, the changes will be updated on disk and logged
1854          * later.
1855          */
1856         lrecs++;
1857         rrecs--;
1858
1859         XFS_BTREE_STATS_INC(cur, lshift);
1860         XFS_BTREE_STATS_ADD(cur, moves, 1);
1861
1862         /*
1863          * If non-leaf, copy a key and a ptr to the left block.
1864          * Log the changes to the left block.
1865          */
1866         if (level > 0) {
1867                 /* It's a non-leaf.  Move keys and pointers. */
1868                 union xfs_btree_key     *lkp;   /* left btree key */
1869                 union xfs_btree_ptr     *lpp;   /* left address pointer */
1870
1871                 lkp = xfs_btree_key_addr(cur, lrecs, left);
1872                 rkp = xfs_btree_key_addr(cur, 1, right);
1873
1874                 lpp = xfs_btree_ptr_addr(cur, lrecs, left);
1875                 rpp = xfs_btree_ptr_addr(cur, 1, right);
1876 #ifdef DEBUG
1877                 error = xfs_btree_check_ptr(cur, rpp, 0, level);
1878                 if (error)
1879                         goto error0;
1880 #endif
1881                 xfs_btree_copy_keys(cur, lkp, rkp, 1);
1882                 xfs_btree_copy_ptrs(cur, lpp, rpp, 1);
1883
1884                 xfs_btree_log_keys(cur, lbp, lrecs, lrecs);
1885                 xfs_btree_log_ptrs(cur, lbp, lrecs, lrecs);
1886
1887                 ASSERT(cur->bc_ops->keys_inorder(cur,
1888                         xfs_btree_key_addr(cur, lrecs - 1, left), lkp));
1889         } else {
1890                 /* It's a leaf.  Move records.  */
1891                 union xfs_btree_rec     *lrp;   /* left record pointer */
1892
1893                 lrp = xfs_btree_rec_addr(cur, lrecs, left);
1894                 rrp = xfs_btree_rec_addr(cur, 1, right);
1895
1896                 xfs_btree_copy_recs(cur, lrp, rrp, 1);
1897                 xfs_btree_log_recs(cur, lbp, lrecs, lrecs);
1898
1899                 ASSERT(cur->bc_ops->recs_inorder(cur,
1900                         xfs_btree_rec_addr(cur, lrecs - 1, left), lrp));
1901         }
1902
1903         xfs_btree_set_numrecs(left, lrecs);
1904         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
1905
1906         xfs_btree_set_numrecs(right, rrecs);
1907         xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
1908
1909         /*
1910          * Slide the contents of right down one entry.
1911          */
1912         XFS_BTREE_STATS_ADD(cur, moves, rrecs - 1);
1913         if (level > 0) {
1914                 /* It's a nonleaf. operate on keys and ptrs */
1915 #ifdef DEBUG
1916                 int                     i;              /* loop index */
1917
1918                 for (i = 0; i < rrecs; i++) {
1919                         error = xfs_btree_check_ptr(cur, rpp, i + 1, level);
1920                         if (error)
1921                                 goto error0;
1922                 }
1923 #endif
1924                 xfs_btree_shift_keys(cur,
1925                                 xfs_btree_key_addr(cur, 2, right),
1926                                 -1, rrecs);
1927                 xfs_btree_shift_ptrs(cur,
1928                                 xfs_btree_ptr_addr(cur, 2, right),
1929                                 -1, rrecs);
1930
1931                 xfs_btree_log_keys(cur, rbp, 1, rrecs);
1932                 xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
1933         } else {
1934                 /* It's a leaf. operate on records */
1935                 xfs_btree_shift_recs(cur,
1936                         xfs_btree_rec_addr(cur, 2, right),
1937                         -1, rrecs);
1938                 xfs_btree_log_recs(cur, rbp, 1, rrecs);
1939
1940                 /*
1941                  * If it's the first record in the block, we'll need a key
1942                  * structure to pass up to the next level (updkey).
1943                  */
1944                 cur->bc_ops->init_key_from_rec(&key,
1945                         xfs_btree_rec_addr(cur, 1, right));
1946                 rkp = &key;
1947         }
1948
1949         /* Update the parent key values of right. */
1950         error = xfs_btree_updkey(cur, rkp, level + 1);
1951         if (error)
1952                 goto error0;
1953
1954         /* Slide the cursor value left one. */
1955         cur->bc_ptrs[level]--;
1956
1957         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1958         *stat = 1;
1959         return 0;
1960
1961 out0:
1962         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1963         *stat = 0;
1964         return 0;
1965
1966 error0:
1967         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1968         return error;
1969 }
1970
1971 /*
1972  * Move 1 record right from cur/level if possible.
1973  * Update cur to reflect the new path.
1974  */
1975 STATIC int                                      /* error */
1976 xfs_btree_rshift(
1977         struct xfs_btree_cur    *cur,
1978         int                     level,
1979         int                     *stat)          /* success/failure */
1980 {
1981         union xfs_btree_key     key;            /* btree key */
1982         struct xfs_buf          *lbp;           /* left buffer pointer */
1983         struct xfs_btree_block  *left;          /* left btree block */
1984         struct xfs_buf          *rbp;           /* right buffer pointer */
1985         struct xfs_btree_block  *right;         /* right btree block */
1986         struct xfs_btree_cur    *tcur;          /* temporary btree cursor */
1987         union xfs_btree_ptr     rptr;           /* right block pointer */
1988         union xfs_btree_key     *rkp;           /* right btree key */
1989         int                     rrecs;          /* right record count */
1990         int                     lrecs;          /* left record count */
1991         int                     error;          /* error return value */
1992         int                     i;              /* loop counter */
1993
1994         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1995         XFS_BTREE_TRACE_ARGI(cur, level);
1996
1997         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1998             (level == cur->bc_nlevels - 1))
1999                 goto out0;
2000
2001         /* Set up variables for this block as "left". */
2002         left = xfs_btree_get_block(cur, level, &lbp);
2003
2004 #ifdef DEBUG
2005         error = xfs_btree_check_block(cur, left, level, lbp);
2006         if (error)
2007                 goto error0;
2008 #endif
2009
2010         /* If we've got no right sibling then we can't shift an entry right. */
2011         xfs_btree_get_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2012         if (xfs_btree_ptr_is_null(cur, &rptr))
2013                 goto out0;
2014
2015         /*
2016          * If the cursor entry is the one that would be moved, don't
2017          * do it... it's too complicated.
2018          */
2019         lrecs = xfs_btree_get_numrecs(left);
2020         if (cur->bc_ptrs[level] >= lrecs)
2021                 goto out0;
2022
2023         /* Set up the right neighbor as "right". */
2024         error = xfs_btree_read_buf_block(cur, &rptr, level, 0, &right, &rbp);
2025         if (error)
2026                 goto error0;
2027
2028         /* If it's full, it can't take another entry. */
2029         rrecs = xfs_btree_get_numrecs(right);
2030         if (rrecs == cur->bc_ops->get_maxrecs(cur, level))
2031                 goto out0;
2032
2033         XFS_BTREE_STATS_INC(cur, rshift);
2034         XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2035
2036         /*
2037          * Make a hole at the start of the right neighbor block, then
2038          * copy the last left block entry to the hole.
2039          */
2040         if (level > 0) {
2041                 /* It's a nonleaf. make a hole in the keys and ptrs */
2042                 union xfs_btree_key     *lkp;
2043                 union xfs_btree_ptr     *lpp;
2044                 union xfs_btree_ptr     *rpp;
2045
2046                 lkp = xfs_btree_key_addr(cur, lrecs, left);
2047                 lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2048                 rkp = xfs_btree_key_addr(cur, 1, right);
2049                 rpp = xfs_btree_ptr_addr(cur, 1, right);
2050
2051 #ifdef DEBUG
2052                 for (i = rrecs - 1; i >= 0; i--) {
2053                         error = xfs_btree_check_ptr(cur, rpp, i, level);
2054                         if (error)
2055                                 goto error0;
2056                 }
2057 #endif
2058
2059                 xfs_btree_shift_keys(cur, rkp, 1, rrecs);
2060                 xfs_btree_shift_ptrs(cur, rpp, 1, rrecs);
2061
2062 #ifdef DEBUG
2063                 error = xfs_btree_check_ptr(cur, lpp, 0, level);
2064                 if (error)
2065                         goto error0;
2066 #endif
2067
2068                 /* Now put the new data in, and log it. */
2069                 xfs_btree_copy_keys(cur, rkp, lkp, 1);
2070                 xfs_btree_copy_ptrs(cur, rpp, lpp, 1);
2071
2072                 xfs_btree_log_keys(cur, rbp, 1, rrecs + 1);
2073                 xfs_btree_log_ptrs(cur, rbp, 1, rrecs + 1);
2074
2075                 ASSERT(cur->bc_ops->keys_inorder(cur, rkp,
2076                         xfs_btree_key_addr(cur, 2, right)));
2077         } else {
2078                 /* It's a leaf. make a hole in the records */
2079                 union xfs_btree_rec     *lrp;
2080                 union xfs_btree_rec     *rrp;
2081
2082                 lrp = xfs_btree_rec_addr(cur, lrecs, left);
2083                 rrp = xfs_btree_rec_addr(cur, 1, right);
2084
2085                 xfs_btree_shift_recs(cur, rrp, 1, rrecs);
2086
2087                 /* Now put the new data in, and log it. */
2088                 xfs_btree_copy_recs(cur, rrp, lrp, 1);
2089                 xfs_btree_log_recs(cur, rbp, 1, rrecs + 1);
2090
2091                 cur->bc_ops->init_key_from_rec(&key, rrp);
2092                 rkp = &key;
2093
2094                 ASSERT(cur->bc_ops->recs_inorder(cur, rrp,
2095                         xfs_btree_rec_addr(cur, 2, right)));
2096         }
2097
2098         /*
2099          * Decrement and log left's numrecs, bump and log right's numrecs.
2100          */
2101         xfs_btree_set_numrecs(left, --lrecs);
2102         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2103
2104         xfs_btree_set_numrecs(right, ++rrecs);
2105         xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2106
2107         /*
2108          * Using a temporary cursor, update the parent key values of the
2109          * block on the right.
2110          */
2111         error = xfs_btree_dup_cursor(cur, &tcur);
2112         if (error)
2113                 goto error0;
2114         i = xfs_btree_lastrec(tcur, level);
2115         XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
2116
2117         error = xfs_btree_increment(tcur, level, &i);
2118         if (error)
2119                 goto error1;
2120
2121         error = xfs_btree_updkey(tcur, rkp, level + 1);
2122         if (error)
2123                 goto error1;
2124
2125         xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2126
2127         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2128         *stat = 1;
2129         return 0;
2130
2131 out0:
2132         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2133         *stat = 0;
2134         return 0;
2135
2136 error0:
2137         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2138         return error;
2139
2140 error1:
2141         XFS_BTREE_TRACE_CURSOR(tcur, XBT_ERROR);
2142         xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2143         return error;
2144 }
2145
2146 /*
2147  * Split cur/level block in half.
2148  * Return new block number and the key to its first
2149  * record (to be inserted into parent).
2150  */
2151 STATIC int                                      /* error */
2152 xfs_btree_split(
2153         struct xfs_btree_cur    *cur,
2154         int                     level,
2155         union xfs_btree_ptr     *ptrp,
2156         union xfs_btree_key     *key,
2157         struct xfs_btree_cur    **curp,
2158         int                     *stat)          /* success/failure */
2159 {
2160         union xfs_btree_ptr     lptr;           /* left sibling block ptr */
2161         struct xfs_buf          *lbp;           /* left buffer pointer */
2162         struct xfs_btree_block  *left;          /* left btree block */
2163         union xfs_btree_ptr     rptr;           /* right sibling block ptr */
2164         struct xfs_buf          *rbp;           /* right buffer pointer */
2165         struct xfs_btree_block  *right;         /* right btree block */
2166         union xfs_btree_ptr     rrptr;          /* right-right sibling ptr */
2167         struct xfs_buf          *rrbp;          /* right-right buffer pointer */
2168         struct xfs_btree_block  *rrblock;       /* right-right btree block */
2169         int                     lrecs;
2170         int                     rrecs;
2171         int                     src_index;
2172         int                     error;          /* error return value */
2173 #ifdef DEBUG
2174         int                     i;
2175 #endif
2176
2177         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2178         XFS_BTREE_TRACE_ARGIPK(cur, level, *ptrp, key);
2179
2180         XFS_BTREE_STATS_INC(cur, split);
2181
2182         /* Set up left block (current one). */
2183         left = xfs_btree_get_block(cur, level, &lbp);
2184
2185 #ifdef DEBUG
2186         error = xfs_btree_check_block(cur, left, level, lbp);
2187         if (error)
2188                 goto error0;
2189 #endif
2190
2191         xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2192
2193         /* Allocate the new block. If we can't do it, we're toast. Give up. */
2194         error = cur->bc_ops->alloc_block(cur, &lptr, &rptr, 1, stat);
2195         if (error)
2196                 goto error0;
2197         if (*stat == 0)
2198                 goto out0;
2199         XFS_BTREE_STATS_INC(cur, alloc);
2200
2201         /* Set up the new block as "right". */
2202         error = xfs_btree_get_buf_block(cur, &rptr, 0, &right, &rbp);
2203         if (error)
2204                 goto error0;
2205
2206         /* Fill in the btree header for the new right block. */
2207         xfs_btree_init_block_cur(cur, xfs_btree_get_level(left), 0, rbp);
2208
2209         /*
2210          * Split the entries between the old and the new block evenly.
2211          * Make sure that if there's an odd number of entries now, that
2212          * each new block will have the same number of entries.
2213          */
2214         lrecs = xfs_btree_get_numrecs(left);
2215         rrecs = lrecs / 2;
2216         if ((lrecs & 1) && cur->bc_ptrs[level] <= rrecs + 1)
2217                 rrecs++;
2218         src_index = (lrecs - rrecs + 1);
2219
2220         XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2221
2222         /*
2223          * Copy btree block entries from the left block over to the
2224          * new block, the right. Update the right block and log the
2225          * changes.
2226          */
2227         if (level > 0) {
2228                 /* It's a non-leaf.  Move keys and pointers. */
2229                 union xfs_btree_key     *lkp;   /* left btree key */
2230                 union xfs_btree_ptr     *lpp;   /* left address pointer */
2231                 union xfs_btree_key     *rkp;   /* right btree key */
2232                 union xfs_btree_ptr     *rpp;   /* right address pointer */
2233
2234                 lkp = xfs_btree_key_addr(cur, src_index, left);
2235                 lpp = xfs_btree_ptr_addr(cur, src_index, left);
2236                 rkp = xfs_btree_key_addr(cur, 1, right);
2237                 rpp = xfs_btree_ptr_addr(cur, 1, right);
2238
2239 #ifdef DEBUG
2240                 for (i = src_index; i < rrecs; i++) {
2241                         error = xfs_btree_check_ptr(cur, lpp, i, level);
2242                         if (error)
2243                                 goto error0;
2244                 }
2245 #endif
2246
2247                 xfs_btree_copy_keys(cur, rkp, lkp, rrecs);
2248                 xfs_btree_copy_ptrs(cur, rpp, lpp, rrecs);
2249
2250                 xfs_btree_log_keys(cur, rbp, 1, rrecs);
2251                 xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2252
2253                 /* Grab the keys to the entries moved to the right block */
2254                 xfs_btree_copy_keys(cur, key, rkp, 1);
2255         } else {
2256                 /* It's a leaf.  Move records.  */
2257                 union xfs_btree_rec     *lrp;   /* left record pointer */
2258                 union xfs_btree_rec     *rrp;   /* right record pointer */
2259
2260                 lrp = xfs_btree_rec_addr(cur, src_index, left);
2261                 rrp = xfs_btree_rec_addr(cur, 1, right);
2262
2263                 xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
2264                 xfs_btree_log_recs(cur, rbp, 1, rrecs);
2265
2266                 cur->bc_ops->init_key_from_rec(key,
2267                         xfs_btree_rec_addr(cur, 1, right));
2268         }
2269
2270
2271         /*
2272          * Find the left block number by looking in the buffer.
2273          * Adjust numrecs, sibling pointers.
2274          */
2275         xfs_btree_get_sibling(cur, left, &rrptr, XFS_BB_RIGHTSIB);
2276         xfs_btree_set_sibling(cur, right, &rrptr, XFS_BB_RIGHTSIB);
2277         xfs_btree_set_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2278         xfs_btree_set_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2279
2280         lrecs -= rrecs;
2281         xfs_btree_set_numrecs(left, lrecs);
2282         xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
2283
2284         xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
2285         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
2286
2287         /*
2288          * If there's a block to the new block's right, make that block
2289          * point back to right instead of to left.
2290          */
2291         if (!xfs_btree_ptr_is_null(cur, &rrptr)) {
2292                 error = xfs_btree_read_buf_block(cur, &rrptr, level,
2293                                                         0, &rrblock, &rrbp);
2294                 if (error)
2295                         goto error0;
2296                 xfs_btree_set_sibling(cur, rrblock, &rptr, XFS_BB_LEFTSIB);
2297                 xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
2298         }
2299         /*
2300          * If the cursor is really in the right block, move it there.
2301          * If it's just pointing past the last entry in left, then we'll
2302          * insert there, so don't change anything in that case.
2303          */
2304         if (cur->bc_ptrs[level] > lrecs + 1) {
2305                 xfs_btree_setbuf(cur, level, rbp);
2306                 cur->bc_ptrs[level] -= lrecs;
2307         }
2308         /*
2309          * If there are more levels, we'll need another cursor which refers
2310          * the right block, no matter where this cursor was.
2311          */
2312         if (level + 1 < cur->bc_nlevels) {
2313                 error = xfs_btree_dup_cursor(cur, curp);
2314                 if (error)
2315                         goto error0;
2316                 (*curp)->bc_ptrs[level + 1]++;
2317         }
2318         *ptrp = rptr;
2319         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2320         *stat = 1;
2321         return 0;
2322 out0:
2323         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2324         *stat = 0;
2325         return 0;
2326
2327 error0:
2328         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2329         return error;
2330 }
2331
2332 /*
2333  * Copy the old inode root contents into a real block and make the
2334  * broot point to it.
2335  */
2336 int                                             /* error */
2337 xfs_btree_new_iroot(
2338         struct xfs_btree_cur    *cur,           /* btree cursor */
2339         int                     *logflags,      /* logging flags for inode */
2340         int                     *stat)          /* return status - 0 fail */
2341 {
2342         struct xfs_buf          *cbp;           /* buffer for cblock */
2343         struct xfs_btree_block  *block;         /* btree block */
2344         struct xfs_btree_block  *cblock;        /* child btree block */
2345         union xfs_btree_key     *ckp;           /* child key pointer */
2346         union xfs_btree_ptr     *cpp;           /* child ptr pointer */
2347         union xfs_btree_key     *kp;            /* pointer to btree key */
2348         union xfs_btree_ptr     *pp;            /* pointer to block addr */
2349         union xfs_btree_ptr     nptr;           /* new block addr */
2350         int                     level;          /* btree level */
2351         int                     error;          /* error return code */
2352 #ifdef DEBUG
2353         int                     i;              /* loop counter */
2354 #endif
2355
2356         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2357         XFS_BTREE_STATS_INC(cur, newroot);
2358
2359         ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
2360
2361         level = cur->bc_nlevels - 1;
2362
2363         block = xfs_btree_get_iroot(cur);
2364         pp = xfs_btree_ptr_addr(cur, 1, block);
2365
2366         /* Allocate the new block. If we can't do it, we're toast. Give up. */
2367         error = cur->bc_ops->alloc_block(cur, pp, &nptr, 1, stat);
2368         if (error)
2369                 goto error0;
2370         if (*stat == 0) {
2371                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2372                 return 0;
2373         }
2374         XFS_BTREE_STATS_INC(cur, alloc);
2375
2376         /* Copy the root into a real block. */
2377         error = xfs_btree_get_buf_block(cur, &nptr, 0, &cblock, &cbp);
2378         if (error)
2379                 goto error0;
2380
2381         memcpy(cblock, block, xfs_btree_block_len(cur));
2382
2383         be16_add_cpu(&block->bb_level, 1);
2384         xfs_btree_set_numrecs(block, 1);
2385         cur->bc_nlevels++;
2386         cur->bc_ptrs[level + 1] = 1;
2387
2388         kp = xfs_btree_key_addr(cur, 1, block);
2389         ckp = xfs_btree_key_addr(cur, 1, cblock);
2390         xfs_btree_copy_keys(cur, ckp, kp, xfs_btree_get_numrecs(cblock));
2391
2392         cpp = xfs_btree_ptr_addr(cur, 1, cblock);
2393 #ifdef DEBUG
2394         for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
2395                 error = xfs_btree_check_ptr(cur, pp, i, level);
2396                 if (error)
2397                         goto error0;
2398         }
2399 #endif
2400         xfs_btree_copy_ptrs(cur, cpp, pp, xfs_btree_get_numrecs(cblock));
2401
2402 #ifdef DEBUG
2403         error = xfs_btree_check_ptr(cur, &nptr, 0, level);
2404         if (error)
2405                 goto error0;
2406 #endif
2407         xfs_btree_copy_ptrs(cur, pp, &nptr, 1);
2408
2409         xfs_iroot_realloc(cur->bc_private.b.ip,
2410                           1 - xfs_btree_get_numrecs(cblock),
2411                           cur->bc_private.b.whichfork);
2412
2413         xfs_btree_setbuf(cur, level, cbp);
2414
2415         /*
2416          * Do all this logging at the end so that
2417          * the root is at the right level.
2418          */
2419         xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
2420         xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
2421         xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
2422
2423         *logflags |=
2424                 XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_private.b.whichfork);
2425         *stat = 1;
2426         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2427         return 0;
2428 error0:
2429         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2430         return error;
2431 }
2432
2433 /*
2434  * Allocate a new root block, fill it in.
2435  */
2436 STATIC int                              /* error */
2437 xfs_btree_new_root(
2438         struct xfs_btree_cur    *cur,   /* btree cursor */
2439         int                     *stat)  /* success/failure */
2440 {
2441         struct xfs_btree_block  *block; /* one half of the old root block */
2442         struct xfs_buf          *bp;    /* buffer containing block */
2443         int                     error;  /* error return value */
2444         struct xfs_buf          *lbp;   /* left buffer pointer */
2445         struct xfs_btree_block  *left;  /* left btree block */
2446         struct xfs_buf          *nbp;   /* new (root) buffer */
2447         struct xfs_btree_block  *new;   /* new (root) btree block */
2448         int                     nptr;   /* new value for key index, 1 or 2 */
2449         struct xfs_buf          *rbp;   /* right buffer pointer */
2450         struct xfs_btree_block  *right; /* right btree block */
2451         union xfs_btree_ptr     rptr;
2452         union xfs_btree_ptr     lptr;
2453
2454         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2455         XFS_BTREE_STATS_INC(cur, newroot);
2456
2457         /* initialise our start point from the cursor */
2458         cur->bc_ops->init_ptr_from_cur(cur, &rptr);
2459
2460         /* Allocate the new block. If we can't do it, we're toast. Give up. */
2461         error = cur->bc_ops->alloc_block(cur, &rptr, &lptr, 1, stat);
2462         if (error)
2463                 goto error0;
2464         if (*stat == 0)
2465                 goto out0;
2466         XFS_BTREE_STATS_INC(cur, alloc);
2467
2468         /* Set up the new block. */
2469         error = xfs_btree_get_buf_block(cur, &lptr, 0, &new, &nbp);
2470         if (error)
2471                 goto error0;
2472
2473         /* Set the root in the holding structure  increasing the level by 1. */
2474         cur->bc_ops->set_root(cur, &lptr, 1);
2475
2476         /*
2477          * At the previous root level there are now two blocks: the old root,
2478          * and the new block generated when it was split.  We don't know which
2479          * one the cursor is pointing at, so we set up variables "left" and
2480          * "right" for each case.
2481          */
2482         block = xfs_btree_get_block(cur, cur->bc_nlevels - 1, &bp);
2483
2484 #ifdef DEBUG
2485         error = xfs_btree_check_block(cur, block, cur->bc_nlevels - 1, bp);
2486         if (error)
2487                 goto error0;
2488 #endif
2489
2490         xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
2491         if (!xfs_btree_ptr_is_null(cur, &rptr)) {
2492                 /* Our block is left, pick up the right block. */
2493                 lbp = bp;
2494                 xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2495                 left = block;
2496                 error = xfs_btree_read_buf_block(cur, &rptr,
2497                                         cur->bc_nlevels - 1, 0, &right, &rbp);
2498                 if (error)
2499                         goto error0;
2500                 bp = rbp;
2501                 nptr = 1;
2502         } else {
2503                 /* Our block is right, pick up the left block. */
2504                 rbp = bp;
2505                 xfs_btree_buf_to_ptr(cur, rbp, &rptr);
2506                 right = block;
2507                 xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2508                 error = xfs_btree_read_buf_block(cur, &lptr,
2509                                         cur->bc_nlevels - 1, 0, &left, &lbp);
2510                 if (error)
2511                         goto error0;
2512                 bp = lbp;
2513                 nptr = 2;
2514         }
2515         /* Fill in the new block's btree header and log it. */
2516         xfs_btree_init_block_cur(cur, cur->bc_nlevels, 2, nbp);
2517         xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
2518         ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
2519                         !xfs_btree_ptr_is_null(cur, &rptr));
2520
2521         /* Fill in the key data in the new root. */
2522         if (xfs_btree_get_level(left) > 0) {
2523                 xfs_btree_copy_keys(cur,
2524                                 xfs_btree_key_addr(cur, 1, new),
2525                                 xfs_btree_key_addr(cur, 1, left), 1);
2526                 xfs_btree_copy_keys(cur,
2527                                 xfs_btree_key_addr(cur, 2, new),
2528                                 xfs_btree_key_addr(cur, 1, right), 1);
2529         } else {
2530                 cur->bc_ops->init_key_from_rec(
2531                                 xfs_btree_key_addr(cur, 1, new),
2532                                 xfs_btree_rec_addr(cur, 1, left));
2533                 cur->bc_ops->init_key_from_rec(
2534                                 xfs_btree_key_addr(cur, 2, new),
2535                                 xfs_btree_rec_addr(cur, 1, right));
2536         }
2537         xfs_btree_log_keys(cur, nbp, 1, 2);
2538
2539         /* Fill in the pointer data in the new root. */
2540         xfs_btree_copy_ptrs(cur,
2541                 xfs_btree_ptr_addr(cur, 1, new), &lptr, 1);
2542         xfs_btree_copy_ptrs(cur,
2543                 xfs_btree_ptr_addr(cur, 2, new), &rptr, 1);
2544         xfs_btree_log_ptrs(cur, nbp, 1, 2);
2545
2546         /* Fix up the cursor. */
2547         xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
2548         cur->bc_ptrs[cur->bc_nlevels] = nptr;
2549         cur->bc_nlevels++;
2550         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2551         *stat = 1;
2552         return 0;
2553 error0:
2554         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2555         return error;
2556 out0:
2557         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2558         *stat = 0;
2559         return 0;
2560 }
2561
2562 STATIC int
2563 xfs_btree_make_block_unfull(
2564         struct xfs_btree_cur    *cur,   /* btree cursor */
2565         int                     level,  /* btree level */
2566         int                     numrecs,/* # of recs in block */
2567         int                     *oindex,/* old tree index */
2568         int                     *index, /* new tree index */
2569         union xfs_btree_ptr     *nptr,  /* new btree ptr */
2570         struct xfs_btree_cur    **ncur, /* new btree cursor */
2571         union xfs_btree_rec     *nrec,  /* new record */
2572         int                     *stat)
2573 {
2574         union xfs_btree_key     key;    /* new btree key value */
2575         int                     error = 0;
2576
2577         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2578             level == cur->bc_nlevels - 1) {
2579                 struct xfs_inode *ip = cur->bc_private.b.ip;
2580
2581                 if (numrecs < cur->bc_ops->get_dmaxrecs(cur, level)) {
2582                         /* A root block that can be made bigger. */
2583
2584                         xfs_iroot_realloc(ip, 1, cur->bc_private.b.whichfork);
2585                 } else {
2586                         /* A root block that needs replacing */
2587                         int     logflags = 0;
2588
2589                         error = xfs_btree_new_iroot(cur, &logflags, stat);
2590                         if (error || *stat == 0)
2591                                 return error;
2592
2593                         xfs_trans_log_inode(cur->bc_tp, ip, logflags);
2594                 }
2595
2596                 return 0;
2597         }
2598
2599         /* First, try shifting an entry to the right neighbor. */
2600         error = xfs_btree_rshift(cur, level, stat);
2601         if (error || *stat)
2602                 return error;
2603
2604         /* Next, try shifting an entry to the left neighbor. */
2605         error = xfs_btree_lshift(cur, level, stat);
2606         if (error)
2607                 return error;
2608
2609         if (*stat) {
2610                 *oindex = *index = cur->bc_ptrs[level];
2611                 return 0;
2612         }
2613
2614         /*
2615          * Next, try splitting the current block in half.
2616          *
2617          * If this works we have to re-set our variables because we
2618          * could be in a different block now.
2619          */
2620         error = xfs_btree_split(cur, level, nptr, &key, ncur, stat);
2621         if (error || *stat == 0)
2622                 return error;
2623
2624
2625         *index = cur->bc_ptrs[level];
2626         cur->bc_ops->init_rec_from_key(&key, nrec);
2627         return 0;
2628 }
2629
2630 /*
2631  * Insert one record/level.  Return information to the caller
2632  * allowing the next level up to proceed if necessary.
2633  */
2634 STATIC int
2635 xfs_btree_insrec(
2636         struct xfs_btree_cur    *cur,   /* btree cursor */
2637         int                     level,  /* level to insert record at */
2638         union xfs_btree_ptr     *ptrp,  /* i/o: block number inserted */
2639         union xfs_btree_rec     *recp,  /* i/o: record data inserted */
2640         struct xfs_btree_cur    **curp, /* output: new cursor replacing cur */
2641         int                     *stat)  /* success/failure */
2642 {
2643         struct xfs_btree_block  *block; /* btree block */
2644         struct xfs_buf          *bp;    /* buffer for block */
2645         union xfs_btree_key     key;    /* btree key */
2646         union xfs_btree_ptr     nptr;   /* new block ptr */
2647         struct xfs_btree_cur    *ncur;  /* new btree cursor */
2648         union xfs_btree_rec     nrec;   /* new record count */
2649         int                     optr;   /* old key/record index */
2650         int                     ptr;    /* key/record index */
2651         int                     numrecs;/* number of records */
2652         int                     error;  /* error return value */
2653 #ifdef DEBUG
2654         int                     i;
2655 #endif
2656
2657         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2658         XFS_BTREE_TRACE_ARGIPR(cur, level, *ptrp, recp);
2659
2660         ncur = NULL;
2661
2662         /*
2663          * If we have an external root pointer, and we've made it to the
2664          * root level, allocate a new root block and we're done.
2665          */
2666         if (!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2667             (level >= cur->bc_nlevels)) {
2668                 error = xfs_btree_new_root(cur, stat);
2669                 xfs_btree_set_ptr_null(cur, ptrp);
2670
2671                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2672                 return error;
2673         }
2674
2675         /* If we're off the left edge, return failure. */
2676         ptr = cur->bc_ptrs[level];
2677         if (ptr == 0) {
2678                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2679                 *stat = 0;
2680                 return 0;
2681         }
2682
2683         /* Make a key out of the record data to be inserted, and save it. */
2684         cur->bc_ops->init_key_from_rec(&key, recp);
2685
2686         optr = ptr;
2687
2688         XFS_BTREE_STATS_INC(cur, insrec);
2689
2690         /* Get pointers to the btree buffer and block. */
2691         block = xfs_btree_get_block(cur, level, &bp);
2692         numrecs = xfs_btree_get_numrecs(block);
2693
2694 #ifdef DEBUG
2695         error = xfs_btree_check_block(cur, block, level, bp);
2696         if (error)
2697                 goto error0;
2698
2699         /* Check that the new entry is being inserted in the right place. */
2700         if (ptr <= numrecs) {
2701                 if (level == 0) {
2702                         ASSERT(cur->bc_ops->recs_inorder(cur, recp,
2703                                 xfs_btree_rec_addr(cur, ptr, block)));
2704                 } else {
2705                         ASSERT(cur->bc_ops->keys_inorder(cur, &key,
2706                                 xfs_btree_key_addr(cur, ptr, block)));
2707                 }
2708         }
2709 #endif
2710
2711         /*
2712          * If the block is full, we can't insert the new entry until we
2713          * make the block un-full.
2714          */
2715         xfs_btree_set_ptr_null(cur, &nptr);
2716         if (numrecs == cur->bc_ops->get_maxrecs(cur, level)) {
2717                 error = xfs_btree_make_block_unfull(cur, level, numrecs,
2718                                         &optr, &ptr, &nptr, &ncur, &nrec, stat);
2719                 if (error || *stat == 0)
2720                         goto error0;
2721         }
2722
2723         /*
2724          * The current block may have changed if the block was
2725          * previously full and we have just made space in it.
2726          */
2727         block = xfs_btree_get_block(cur, level, &bp);
2728         numrecs = xfs_btree_get_numrecs(block);
2729
2730 #ifdef DEBUG
2731         error = xfs_btree_check_block(cur, block, level, bp);
2732         if (error)
2733                 return error;
2734 #endif
2735
2736         /*
2737          * At this point we know there's room for our new entry in the block
2738          * we're pointing at.
2739          */
2740         XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr + 1);
2741
2742         if (level > 0) {
2743                 /* It's a nonleaf. make a hole in the keys and ptrs */
2744                 union xfs_btree_key     *kp;
2745                 union xfs_btree_ptr     *pp;
2746
2747                 kp = xfs_btree_key_addr(cur, ptr, block);
2748                 pp = xfs_btree_ptr_addr(cur, ptr, block);
2749
2750 #ifdef DEBUG
2751                 for (i = numrecs - ptr; i >= 0; i--) {
2752                         error = xfs_btree_check_ptr(cur, pp, i, level);
2753                         if (error)
2754                                 return error;
2755                 }
2756 #endif
2757
2758                 xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1);
2759                 xfs_btree_shift_ptrs(cur, pp, 1, numrecs - ptr + 1);
2760
2761 #ifdef DEBUG
2762                 error = xfs_btree_check_ptr(cur, ptrp, 0, level);
2763                 if (error)
2764                         goto error0;
2765 #endif
2766
2767                 /* Now put the new data in, bump numrecs and log it. */
2768                 xfs_btree_copy_keys(cur, kp, &key, 1);
2769                 xfs_btree_copy_ptrs(cur, pp, ptrp, 1);
2770                 numrecs++;
2771                 xfs_btree_set_numrecs(block, numrecs);
2772                 xfs_btree_log_ptrs(cur, bp, ptr, numrecs);
2773                 xfs_btree_log_keys(cur, bp, ptr, numrecs);
2774 #ifdef DEBUG
2775                 if (ptr < numrecs) {
2776                         ASSERT(cur->bc_ops->keys_inorder(cur, kp,
2777                                 xfs_btree_key_addr(cur, ptr + 1, block)));
2778                 }
2779 #endif
2780         } else {
2781                 /* It's a leaf. make a hole in the records */
2782                 union xfs_btree_rec             *rp;
2783
2784                 rp = xfs_btree_rec_addr(cur, ptr, block);
2785
2786                 xfs_btree_shift_recs(cur, rp, 1, numrecs - ptr + 1);
2787
2788                 /* Now put the new data in, bump numrecs and log it. */
2789                 xfs_btree_copy_recs(cur, rp, recp, 1);
2790                 xfs_btree_set_numrecs(block, ++numrecs);
2791                 xfs_btree_log_recs(cur, bp, ptr, numrecs);
2792 #ifdef DEBUG
2793                 if (ptr < numrecs) {
2794                         ASSERT(cur->bc_ops->recs_inorder(cur, rp,
2795                                 xfs_btree_rec_addr(cur, ptr + 1, block)));
2796                 }
2797 #endif
2798         }
2799
2800         /* Log the new number of records in the btree header. */
2801         xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
2802
2803         /* If we inserted at the start of a block, update the parents' keys. */
2804         if (optr == 1) {
2805                 error = xfs_btree_updkey(cur, &key, level + 1);
2806                 if (error)
2807                         goto error0;
2808         }
2809
2810         /*
2811          * If we are tracking the last record in the tree and
2812          * we are at the far right edge of the tree, update it.
2813          */
2814         if (xfs_btree_is_lastrec(cur, block, level)) {
2815                 cur->bc_ops->update_lastrec(cur, block, recp,
2816                                             ptr, LASTREC_INSREC);
2817         }
2818
2819         /*
2820          * Return the new block number, if any.
2821          * If there is one, give back a record value and a cursor too.
2822          */
2823         *ptrp = nptr;
2824         if (!xfs_btree_ptr_is_null(cur, &nptr)) {
2825                 *recp = nrec;
2826                 *curp = ncur;
2827         }
2828
2829         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2830         *stat = 1;
2831         return 0;
2832
2833 error0:
2834         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2835         return error;
2836 }
2837
2838 /*
2839  * Insert the record at the point referenced by cur.
2840  *
2841  * A multi-level split of the tree on insert will invalidate the original
2842  * cursor.  All callers of this function should assume that the cursor is
2843  * no longer valid and revalidate it.
2844  */
2845 int
2846 xfs_btree_insert(
2847         struct xfs_btree_cur    *cur,
2848         int                     *stat)
2849 {
2850         int                     error;  /* error return value */
2851         int                     i;      /* result value, 0 for failure */
2852         int                     level;  /* current level number in btree */
2853         union xfs_btree_ptr     nptr;   /* new block number (split result) */
2854         struct xfs_btree_cur    *ncur;  /* new cursor (split result) */
2855         struct xfs_btree_cur    *pcur;  /* previous level's cursor */
2856         union xfs_btree_rec     rec;    /* record to insert */
2857
2858         level = 0;
2859         ncur = NULL;
2860         pcur = cur;
2861
2862         xfs_btree_set_ptr_null(cur, &nptr);
2863         cur->bc_ops->init_rec_from_cur(cur, &rec);
2864
2865         /*
2866          * Loop going up the tree, starting at the leaf level.
2867          * Stop when we don't get a split block, that must mean that
2868          * the insert is finished with this level.
2869          */
2870         do {
2871                 /*
2872                  * Insert nrec/nptr into this level of the tree.
2873                  * Note if we fail, nptr will be null.
2874                  */
2875                 error = xfs_btree_insrec(pcur, level, &nptr, &rec, &ncur, &i);
2876                 if (error) {
2877                         if (pcur != cur)
2878                                 xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
2879                         goto error0;
2880                 }
2881
2882                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
2883                 level++;
2884
2885                 /*
2886                  * See if the cursor we just used is trash.
2887                  * Can't trash the caller's cursor, but otherwise we should
2888                  * if ncur is a new cursor or we're about to be done.
2889                  */
2890                 if (pcur != cur &&
2891                     (ncur || xfs_btree_ptr_is_null(cur, &nptr))) {
2892                         /* Save the state from the cursor before we trash it */
2893                         if (cur->bc_ops->update_cursor)
2894                                 cur->bc_ops->update_cursor(pcur, cur);
2895                         cur->bc_nlevels = pcur->bc_nlevels;
2896                         xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
2897                 }
2898                 /* If we got a new cursor, switch to it. */
2899                 if (ncur) {
2900                         pcur = ncur;
2901                         ncur = NULL;
2902                 }
2903         } while (!xfs_btree_ptr_is_null(cur, &nptr));
2904
2905         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2906         *stat = i;
2907         return 0;
2908 error0:
2909         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2910         return error;
2911 }
2912
2913 /*
2914  * Try to merge a non-leaf block back into the inode root.
2915  *
2916  * Note: the killroot names comes from the fact that we're effectively
2917  * killing the old root block.  But because we can't just delete the
2918  * inode we have to copy the single block it was pointing to into the
2919  * inode.
2920  */
2921 STATIC int
2922 xfs_btree_kill_iroot(
2923         struct xfs_btree_cur    *cur)
2924 {
2925         int                     whichfork = cur->bc_private.b.whichfork;
2926         struct xfs_inode        *ip = cur->bc_private.b.ip;
2927         struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, whichfork);
2928         struct xfs_btree_block  *block;
2929         struct xfs_btree_block  *cblock;
2930         union xfs_btree_key     *kp;
2931         union xfs_btree_key     *ckp;
2932         union xfs_btree_ptr     *pp;
2933         union xfs_btree_ptr     *cpp;
2934         struct xfs_buf          *cbp;
2935         int                     level;
2936         int                     index;
2937         int                     numrecs;
2938 #ifdef DEBUG
2939         union xfs_btree_ptr     ptr;
2940         int                     i;
2941 #endif
2942
2943         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2944
2945         ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
2946         ASSERT(cur->bc_nlevels > 1);
2947
2948         /*
2949          * Don't deal with the root block needs to be a leaf case.
2950          * We're just going to turn the thing back into extents anyway.
2951          */
2952         level = cur->bc_nlevels - 1;
2953         if (level == 1)
2954                 goto out0;
2955
2956         /*
2957          * Give up if the root has multiple children.
2958          */
2959         block = xfs_btree_get_iroot(cur);
2960         if (xfs_btree_get_numrecs(block) != 1)
2961                 goto out0;
2962
2963         cblock = xfs_btree_get_block(cur, level - 1, &cbp);
2964         numrecs = xfs_btree_get_numrecs(cblock);
2965
2966         /*
2967          * Only do this if the next level will fit.
2968          * Then the data must be copied up to the inode,
2969          * instead of freeing the root you free the next level.
2970          */
2971         if (numrecs > cur->bc_ops->get_dmaxrecs(cur, level))
2972                 goto out0;
2973
2974         XFS_BTREE_STATS_INC(cur, killroot);
2975
2976 #ifdef DEBUG
2977         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
2978         ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
2979         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
2980         ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
2981 #endif
2982
2983         index = numrecs - cur->bc_ops->get_maxrecs(cur, level);
2984         if (index) {
2985                 xfs_iroot_realloc(cur->bc_private.b.ip, index,
2986                                   cur->bc_private.b.whichfork);
2987                 block = ifp->if_broot;
2988         }
2989
2990         be16_add_cpu(&block->bb_numrecs, index);
2991         ASSERT(block->bb_numrecs == cblock->bb_numrecs);
2992
2993         kp = xfs_btree_key_addr(cur, 1, block);
2994         ckp = xfs_btree_key_addr(cur, 1, cblock);
2995         xfs_btree_copy_keys(cur, kp, ckp, numrecs);
2996
2997         pp = xfs_btree_ptr_addr(cur, 1, block);
2998         cpp = xfs_btree_ptr_addr(cur, 1, cblock);
2999 #ifdef DEBUG
3000         for (i = 0; i < numrecs; i++) {
3001                 int             error;
3002
3003                 error = xfs_btree_check_ptr(cur, cpp, i, level - 1);
3004                 if (error) {
3005                         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
3006                         return error;
3007                 }
3008         }
3009 #endif
3010         xfs_btree_copy_ptrs(cur, pp, cpp, numrecs);
3011
3012         cur->bc_ops->free_block(cur, cbp);
3013         XFS_BTREE_STATS_INC(cur, free);
3014
3015         cur->bc_bufs[level - 1] = NULL;
3016         be16_add_cpu(&block->bb_level, -1);
3017         xfs_trans_log_inode(cur->bc_tp, ip,
3018                 XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_private.b.whichfork));
3019         cur->bc_nlevels--;
3020 out0:
3021         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3022         return 0;
3023 }
3024
3025 /*
3026  * Kill the current root node, and replace it with it's only child node.
3027  */
3028 STATIC int
3029 xfs_btree_kill_root(
3030         struct xfs_btree_cur    *cur,
3031         struct xfs_buf          *bp,
3032         int                     level,
3033         union xfs_btree_ptr     *newroot)
3034 {
3035         int                     error;
3036
3037         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
3038         XFS_BTREE_STATS_INC(cur, killroot);
3039
3040         /*
3041          * Update the root pointer, decreasing the level by 1 and then
3042          * free the old root.
3043          */
3044         cur->bc_ops->set_root(cur, newroot, -1);
3045
3046         error = cur->bc_ops->free_block(cur, bp);
3047         if (error) {
3048                 XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
3049                 return error;
3050         }
3051
3052         XFS_BTREE_STATS_INC(cur, free);
3053
3054         cur->bc_bufs[level] = NULL;
3055         cur->bc_ra[level] = 0;
3056         cur->bc_nlevels--;
3057
3058         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3059         return 0;
3060 }
3061
3062 STATIC int
3063 xfs_btree_dec_cursor(
3064         struct xfs_btree_cur    *cur,
3065         int                     level,
3066         int                     *stat)
3067 {
3068         int                     error;
3069         int                     i;
3070
3071         if (level > 0) {
3072                 error = xfs_btree_decrement(cur, level, &i);
3073                 if (error)
3074                         return error;
3075         }
3076
3077         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3078         *stat = 1;
3079         return 0;
3080 }
3081
3082 /*
3083  * Single level of the btree record deletion routine.
3084  * Delete record pointed to by cur/level.
3085  * Remove the record from its block then rebalance the tree.
3086  * Return 0 for error, 1 for done, 2 to go on to the next level.
3087  */
3088 STATIC int                                      /* error */
3089 xfs_btree_delrec(
3090         struct xfs_btree_cur    *cur,           /* btree cursor */
3091         int                     level,          /* level removing record from */
3092         int                     *stat)          /* fail/done/go-on */
3093 {
3094         struct xfs_btree_block  *block;         /* btree block */
3095         union xfs_btree_ptr     cptr;           /* current block ptr */
3096         struct xfs_buf          *bp;            /* buffer for block */
3097         int                     error;          /* error return value */
3098         int                     i;              /* loop counter */
3099         union xfs_btree_key     key;            /* storage for keyp */
3100         union xfs_btree_key     *keyp = &key;   /* passed to the next level */
3101         union xfs_btree_ptr     lptr;           /* left sibling block ptr */
3102         struct xfs_buf          *lbp;           /* left buffer pointer */
3103         struct xfs_btree_block  *left;          /* left btree block */
3104         int                     lrecs = 0;      /* left record count */
3105         int                     ptr;            /* key/record index */
3106         union xfs_btree_ptr     rptr;           /* right sibling block ptr */
3107         struct xfs_buf          *rbp;           /* right buffer pointer */
3108         struct xfs_btree_block  *right;         /* right btree block */
3109         struct xfs_btree_block  *rrblock;       /* right-right btree block */
3110         struct xfs_buf          *rrbp;          /* right-right buffer pointer */
3111         int                     rrecs = 0;      /* right record count */
3112         struct xfs_btree_cur    *tcur;          /* temporary btree cursor */
3113         int                     numrecs;        /* temporary numrec count */
3114
3115         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
3116         XFS_BTREE_TRACE_ARGI(cur, level);
3117
3118         tcur = NULL;
3119
3120         /* Get the index of the entry being deleted, check for nothing there. */
3121         ptr = cur->bc_ptrs[level];
3122         if (ptr == 0) {
3123                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3124                 *stat = 0;
3125                 return 0;
3126         }
3127
3128         /* Get the buffer & block containing the record or key/ptr. */
3129         block = xfs_btree_get_block(cur, level, &bp);
3130         numrecs = xfs_btree_get_numrecs(block);
3131
3132 #ifdef DEBUG
3133         error = xfs_btree_check_block(cur, block, level, bp);
3134         if (error)
3135                 goto error0;
3136 #endif
3137
3138         /* Fail if we're off the end of the block. */
3139         if (ptr > numrecs) {
3140                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3141                 *stat = 0;
3142                 return 0;
3143         }
3144
3145         XFS_BTREE_STATS_INC(cur, delrec);
3146         XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr);
3147
3148         /* Excise the entries being deleted. */
3149         if (level > 0) {
3150                 /* It's a nonleaf. operate on keys and ptrs */
3151                 union xfs_btree_key     *lkp;
3152                 union xfs_btree_ptr     *lpp;
3153
3154                 lkp = xfs_btree_key_addr(cur, ptr + 1, block);
3155                 lpp = xfs_btree_ptr_addr(cur, ptr + 1, block);
3156
3157 #ifdef DEBUG
3158                 for (i = 0; i < numrecs - ptr; i++) {
3159                         error = xfs_btree_check_ptr(cur, lpp, i, level);
3160                         if (error)
3161                                 goto error0;
3162                 }
3163 #endif
3164
3165                 if (ptr < numrecs) {
3166                         xfs_btree_shift_keys(cur, lkp, -1, numrecs - ptr);
3167                         xfs_btree_shift_ptrs(cur, lpp, -1, numrecs - ptr);
3168                         xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
3169                         xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
3170                 }
3171
3172                 /*
3173                  * If it's the first record in the block, we'll need to pass a
3174                  * key up to the next level (updkey).
3175                  */
3176                 if (ptr == 1)
3177                         keyp = xfs_btree_key_addr(cur, 1, block);
3178         } else {
3179                 /* It's a leaf. operate on records */
3180                 if (ptr < numrecs) {
3181                         xfs_btree_shift_recs(cur,
3182                                 xfs_btree_rec_addr(cur, ptr + 1, block),
3183                                 -1, numrecs - ptr);
3184                         xfs_btree_log_recs(cur, bp, ptr, numrecs - 1);
3185                 }
3186
3187                 /*
3188                  * If it's the first record in the block, we'll need a key
3189                  * structure to pass up to the next level (updkey).
3190                  */
3191                 if (ptr == 1) {
3192                         cur->bc_ops->init_key_from_rec(&key,
3193                                         xfs_btree_rec_addr(cur, 1, block));
3194                         keyp = &key;
3195                 }
3196         }
3197
3198         /*
3199          * Decrement and log the number of entries in the block.
3200          */
3201         xfs_btree_set_numrecs(block, --numrecs);
3202         xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3203
3204         /*
3205          * If we are tracking the last record in the tree and
3206          * we are at the far right edge of the tree, update it.
3207          */
3208         if (xfs_btree_is_lastrec(cur, block, level)) {
3209                 cur->bc_ops->update_lastrec(cur, block, NULL,
3210                                             ptr, LASTREC_DELREC);
3211         }
3212
3213         /*
3214          * We're at the root level.  First, shrink the root block in-memory.
3215          * Try to get rid of the next level down.  If we can't then there's
3216          * nothing left to do.
3217          */
3218         if (level == cur->bc_nlevels - 1) {
3219                 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3220                         xfs_iroot_realloc(cur->bc_private.b.ip, -1,
3221                                           cur->bc_private.b.whichfork);
3222
3223                         error = xfs_btree_kill_iroot(cur);
3224                         if (error)
3225                                 goto error0;
3226
3227                         error = xfs_btree_dec_cursor(cur, level, stat);
3228                         if (error)
3229                                 goto error0;
3230                         *stat = 1;
3231                         return 0;
3232                 }
3233
3234                 /*
3235                  * If this is the root level, and there's only one entry left,
3236                  * and it's NOT the leaf level, then we can get rid of this
3237                  * level.
3238                  */
3239                 if (numrecs == 1 && level > 0) {
3240                         union xfs_btree_ptr     *pp;
3241                         /*
3242                          * pp is still set to the first pointer in the block.
3243                          * Make it the new root of the btree.
3244                          */
3245                         pp = xfs_btree_ptr_addr(cur, 1, block);
3246                         error = xfs_btree_kill_root(cur, bp, level, pp);
3247                         if (error)
3248                                 goto error0;
3249                 } else if (level > 0) {
3250                         error = xfs_btree_dec_cursor(cur, level, stat);
3251                         if (error)
3252                                 goto error0;
3253                 }
3254                 *stat = 1;
3255                 return 0;
3256         }
3257
3258         /*
3259          * If we deleted the leftmost entry in the block, update the
3260          * key values above us in the tree.
3261          */
3262         if (ptr == 1) {
3263                 error = xfs_btree_updkey(cur, keyp, level + 1);
3264                 if (error)
3265                         goto error0;
3266         }
3267
3268         /*
3269          * If the number of records remaining in the block is at least
3270          * the minimum, we're done.
3271          */
3272         if (numrecs >= cur->bc_ops->get_minrecs(cur, level)) {
3273                 error = xfs_btree_dec_cursor(cur, level, stat);
3274                 if (error)
3275                         goto error0;
3276                 return 0;
3277         }
3278
3279         /*
3280          * Otherwise, we have to move some records around to keep the
3281          * tree balanced.  Look at the left and right sibling blocks to
3282          * see if we can re-balance by moving only one record.
3283          */
3284         xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3285         xfs_btree_get_sibling(cur, block, &lptr, XFS_BB_LEFTSIB);
3286
3287         if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3288                 /*
3289                  * One child of root, need to get a chance to copy its contents
3290                  * into the root and delete it. Can't go up to next level,
3291                  * there's nothing to delete there.
3292                  */
3293                 if (xfs_btree_ptr_is_null(cur, &rptr) &&
3294                     xfs_btree_ptr_is_null(cur, &lptr) &&
3295                     level == cur->bc_nlevels - 2) {
3296                         error = xfs_btree_kill_iroot(cur);
3297                         if (!error)
3298                                 error = xfs_btree_dec_cursor(cur, level, stat);
3299                         if (error)
3300                                 goto error0;
3301                         return 0;
3302                 }
3303         }
3304
3305         ASSERT(!xfs_btree_ptr_is_null(cur, &rptr) ||
3306                !xfs_btree_ptr_is_null(cur, &lptr));
3307
3308         /*
3309          * Duplicate the cursor so our btree manipulations here won't
3310          * disrupt the next level up.
3311          */
3312         error = xfs_btree_dup_cursor(cur, &tcur);
3313         if (error)
3314                 goto error0;
3315
3316         /*
3317          * If there's a right sibling, see if it's ok to shift an entry
3318          * out of it.
3319          */
3320         if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3321                 /*
3322                  * Move the temp cursor to the last entry in the next block.
3323                  * Actually any entry but the first would suffice.
3324                  */
3325                 i = xfs_btree_lastrec(tcur, level);
3326                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3327
3328                 error = xfs_btree_increment(tcur, level, &i);
3329                 if (error)
3330                         goto error0;
3331                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3332
3333                 i = xfs_btree_lastrec(tcur, level);
3334                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3335
3336                 /* Grab a pointer to the block. */
3337                 right = xfs_btree_get_block(tcur, level, &rbp);
3338 #ifdef DEBUG
3339                 error = xfs_btree_check_block(tcur, right, level, rbp);
3340                 if (error)
3341                         goto error0;
3342 #endif
3343                 /* Grab the current block number, for future use. */
3344                 xfs_btree_get_sibling(tcur, right, &cptr, XFS_BB_LEFTSIB);
3345
3346                 /*
3347                  * If right block is full enough so that removing one entry
3348                  * won't make it too empty, and left-shifting an entry out
3349                  * of right to us works, we're done.
3350                  */
3351                 if (xfs_btree_get_numrecs(right) - 1 >=
3352                     cur->bc_ops->get_minrecs(tcur, level)) {
3353                         error = xfs_btree_lshift(tcur, level, &i);
3354                         if (error)
3355                                 goto error0;
3356                         if (i) {
3357                                 ASSERT(xfs_btree_get_numrecs(block) >=
3358                                        cur->bc_ops->get_minrecs(tcur, level));
3359
3360                                 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3361                                 tcur = NULL;
3362
3363                                 error = xfs_btree_dec_cursor(cur, level, stat);
3364                                 if (error)
3365                                         goto error0;
3366                                 return 0;
3367                         }
3368                 }
3369
3370                 /*
3371                  * Otherwise, grab the number of records in right for
3372                  * future reference, and fix up the temp cursor to point
3373                  * to our block again (last record).
3374                  */
3375                 rrecs = xfs_btree_get_numrecs(right);
3376                 if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3377                         i = xfs_btree_firstrec(tcur, level);
3378                         XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3379
3380                         error = xfs_btree_decrement(tcur, level, &i);
3381                         if (error)
3382                                 goto error0;
3383                         XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3384                 }
3385         }
3386
3387         /*
3388          * If there's a left sibling, see if it's ok to shift an entry
3389          * out of it.
3390          */
3391         if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3392                 /*
3393                  * Move the temp cursor to the first entry in the
3394                  * previous block.
3395                  */
3396                 i = xfs_btree_firstrec(tcur, level);
3397                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3398
3399                 error = xfs_btree_decrement(tcur, level, &i);
3400                 if (error)
3401                         goto error0;
3402                 i = xfs_btree_firstrec(tcur, level);
3403                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3404
3405                 /* Grab a pointer to the block. */
3406                 left = xfs_btree_get_block(tcur, level, &lbp);
3407 #ifdef DEBUG
3408                 error = xfs_btree_check_block(cur, left, level, lbp);
3409                 if (error)
3410                         goto error0;
3411 #endif
3412                 /* Grab the current block number, for future use. */
3413                 xfs_btree_get_sibling(tcur, left, &cptr, XFS_BB_RIGHTSIB);
3414
3415                 /*
3416                  * If left block is full enough so that removing one entry
3417                  * won't make it too empty, and right-shifting an entry out
3418                  * of left to us works, we're done.
3419                  */
3420                 if (xfs_btree_get_numrecs(left) - 1 >=
3421                     cur->bc_ops->get_minrecs(tcur, level)) {
3422                         error = xfs_btree_rshift(tcur, level, &i);
3423                         if (error)
3424                                 goto error0;
3425                         if (i) {
3426                                 ASSERT(xfs_btree_get_numrecs(block) >=
3427                                        cur->bc_ops->get_minrecs(tcur, level));
3428                                 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3429                                 tcur = NULL;
3430                                 if (level == 0)
3431                                         cur->bc_ptrs[0]++;
3432                                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3433                                 *stat = 1;
3434                                 return 0;
3435                         }
3436                 }
3437
3438                 /*
3439                  * Otherwise, grab the number of records in right for
3440                  * future reference.
3441                  */
3442                 lrecs = xfs_btree_get_numrecs(left);
3443         }
3444
3445         /* Delete the temp cursor, we're done with it. */
3446         xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3447         tcur = NULL;
3448
3449         /* If here, we need to do a join to keep the tree balanced. */
3450         ASSERT(!xfs_btree_ptr_is_null(cur, &cptr));
3451
3452         if (!xfs_btree_ptr_is_null(cur, &lptr) &&
3453             lrecs + xfs_btree_get_numrecs(block) <=
3454                         cur->bc_ops->get_maxrecs(cur, level)) {
3455                 /*
3456                  * Set "right" to be the starting block,
3457                  * "left" to be the left neighbor.
3458                  */
3459                 rptr = cptr;
3460                 right = block;
3461                 rbp = bp;
3462                 error = xfs_btree_read_buf_block(cur, &lptr, level,
3463                                                         0, &left, &lbp);
3464                 if (error)
3465                         goto error0;
3466
3467         /*
3468          * If that won't work, see if we can join with the right neighbor block.
3469          */
3470         } else if (!xfs_btree_ptr_is_null(cur, &rptr) &&
3471                    rrecs + xfs_btree_get_numrecs(block) <=
3472                         cur->bc_ops->get_maxrecs(cur, level)) {
3473                 /*
3474                  * Set "left" to be the starting block,
3475                  * "right" to be the right neighbor.
3476                  */
3477                 lptr = cptr;
3478                 left = block;
3479                 lbp = bp;
3480                 error = xfs_btree_read_buf_block(cur, &rptr, level,
3481                                                         0, &right, &rbp);
3482                 if (error)
3483                         goto error0;
3484
3485         /*
3486          * Otherwise, we can't fix the imbalance.
3487          * Just return.  This is probably a logic error, but it's not fatal.
3488          */
3489         } else {
3490                 error = xfs_btree_dec_cursor(cur, level, stat);
3491                 if (error)
3492                         goto error0;
3493                 return 0;
3494         }
3495
3496         rrecs = xfs_btree_get_numrecs(right);
3497         lrecs = xfs_btree_get_numrecs(left);
3498
3499         /*
3500          * We're now going to join "left" and "right" by moving all the stuff
3501          * in "right" to "left" and deleting "right".
3502          */
3503         XFS_BTREE_STATS_ADD(cur, moves, rrecs);
3504         if (level > 0) {
3505                 /* It's a non-leaf.  Move keys and pointers. */
3506                 union xfs_btree_key     *lkp;   /* left btree key */
3507                 union xfs_btree_ptr     *lpp;   /* left address pointer */
3508                 union xfs_btree_key     *rkp;   /* right btree key */
3509                 union xfs_btree_ptr     *rpp;   /* right address pointer */
3510
3511                 lkp = xfs_btree_key_addr(cur, lrecs + 1, left);
3512                 lpp = xfs_btree_ptr_addr(cur, lrecs + 1, left);
3513                 rkp = xfs_btree_key_addr(cur, 1, right);
3514                 rpp = xfs_btree_ptr_addr(cur, 1, right);
3515 #ifdef DEBUG
3516                 for (i = 1; i < rrecs; i++) {
3517                         error = xfs_btree_check_ptr(cur, rpp, i, level);
3518                         if (error)
3519                                 goto error0;
3520                 }
3521 #endif
3522                 xfs_btree_copy_keys(cur, lkp, rkp, rrecs);
3523                 xfs_btree_copy_ptrs(cur, lpp, rpp, rrecs);
3524
3525                 xfs_btree_log_keys(cur, lbp, lrecs + 1, lrecs + rrecs);
3526                 xfs_btree_log_ptrs(cur, lbp, lrecs + 1, lrecs + rrecs);
3527         } else {
3528                 /* It's a leaf.  Move records.  */
3529                 union xfs_btree_rec     *lrp;   /* left record pointer */
3530                 union xfs_btree_rec     *rrp;   /* right record pointer */
3531
3532                 lrp = xfs_btree_rec_addr(cur, lrecs + 1, left);
3533                 rrp = xfs_btree_rec_addr(cur, 1, right);
3534
3535                 xfs_btree_copy_recs(cur, lrp, rrp, rrecs);
3536                 xfs_btree_log_recs(cur, lbp, lrecs + 1, lrecs + rrecs);
3537         }
3538
3539         XFS_BTREE_STATS_INC(cur, join);
3540
3541         /*
3542          * Fix up the number of records and right block pointer in the
3543          * surviving block, and log it.
3544          */
3545         xfs_btree_set_numrecs(left, lrecs + rrecs);
3546         xfs_btree_get_sibling(cur, right, &cptr, XFS_BB_RIGHTSIB),
3547         xfs_btree_set_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
3548         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
3549
3550         /* If there is a right sibling, point it to the remaining block. */
3551         xfs_btree_get_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
3552         if (!xfs_btree_ptr_is_null(cur, &cptr)) {
3553                 error = xfs_btree_read_buf_block(cur, &cptr, level,
3554                                                         0, &rrblock, &rrbp);
3555                 if (error)
3556                         goto error0;
3557                 xfs_btree_set_sibling(cur, rrblock, &lptr, XFS_BB_LEFTSIB);
3558                 xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
3559         }
3560
3561         /* Free the deleted block. */
3562         error = cur->bc_ops->free_block(cur, rbp);
3563         if (error)
3564                 goto error0;
3565         XFS_BTREE_STATS_INC(cur, free);
3566
3567         /*
3568          * If we joined with the left neighbor, set the buffer in the
3569          * cursor to the left block, and fix up the index.
3570          */
3571         if (bp != lbp) {
3572                 cur->bc_bufs[level] = lbp;
3573                 cur->bc_ptrs[level] += lrecs;
3574                 cur->bc_ra[level] = 0;
3575         }
3576         /*
3577          * If we joined with the right neighbor and there's a level above
3578          * us, increment the cursor at that level.
3579          */
3580         else if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) ||
3581                    (level + 1 < cur->bc_nlevels)) {
3582                 error = xfs_btree_increment(cur, level + 1, &i);
3583                 if (error)
3584                         goto error0;
3585         }
3586
3587         /*
3588          * Readjust the ptr at this level if it's not a leaf, since it's
3589          * still pointing at the deletion point, which makes the cursor
3590          * inconsistent.  If this makes the ptr 0, the caller fixes it up.
3591          * We can't use decrement because it would change the next level up.
3592          */
3593         if (level > 0)
3594                 cur->bc_ptrs[level]--;
3595
3596         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3597         /* Return value means the next level up has something to do. */
3598         *stat = 2;
3599         return 0;
3600
3601 error0:
3602         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
3603         if (tcur)
3604                 xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
3605         return error;
3606 }
3607
3608 /*
3609  * Delete the record pointed to by cur.
3610  * The cursor refers to the place where the record was (could be inserted)
3611  * when the operation returns.
3612  */
3613 int                                     /* error */
3614 xfs_btree_delete(
3615         struct xfs_btree_cur    *cur,
3616         int                     *stat)  /* success/failure */
3617 {
3618         int                     error;  /* error return value */
3619         int                     level;
3620         int                     i;
3621
3622         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
3623
3624         /*
3625          * Go up the tree, starting at leaf level.
3626          *
3627          * If 2 is returned then a join was done; go to the next level.
3628          * Otherwise we are done.
3629          */
3630         for (level = 0, i = 2; i == 2; level++) {
3631                 error = xfs_btree_delrec(cur, level, &i);
3632                 if (error)
3633                         goto error0;
3634         }
3635
3636         if (i == 0) {
3637                 for (level = 1; level < cur->bc_nlevels; level++) {
3638                         if (cur->bc_ptrs[level] == 0) {
3639                                 error = xfs_btree_decrement(cur, level, &i);
3640                                 if (error)
3641                                         goto error0;
3642                                 break;
3643                         }
3644                 }
3645         }
3646
3647         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3648         *stat = i;
3649         return 0;
3650 error0:
3651         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
3652         return error;
3653 }
3654
3655 /*
3656  * Get the data from the pointed-to record.
3657  */
3658 int                                     /* error */
3659 xfs_btree_get_rec(
3660         struct xfs_btree_cur    *cur,   /* btree cursor */
3661         union xfs_btree_rec     **recp, /* output: btree record */
3662         int                     *stat)  /* output: success/failure */
3663 {
3664         struct xfs_btree_block  *block; /* btree block */
3665         struct xfs_buf          *bp;    /* buffer pointer */
3666         int                     ptr;    /* record number */
3667 #ifdef DEBUG
3668         int                     error;  /* error return value */
3669 #endif
3670
3671         ptr = cur->bc_ptrs[0];
3672         block = xfs_btree_get_block(cur, 0, &bp);
3673
3674 #ifdef DEBUG
3675         error = xfs_btree_check_block(cur, block, 0, bp);
3676         if (error)
3677                 return error;
3678 #endif
3679
3680         /*
3681          * Off the right end or left end, return failure.
3682          */
3683         if (ptr > xfs_btree_get_numrecs(block) || ptr <= 0) {
3684                 *stat = 0;
3685                 return 0;
3686         }
3687
3688         /*
3689          * Point to the record and extract its data.
3690          */
3691         *recp = xfs_btree_rec_addr(cur, ptr, block);
3692         *stat = 1;
3693         return 0;
3694 }