fs/xfs/xfs_btree.c

   1 /*
   2  * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #include "xfs.h"
  19 #include "xfs_fs.h"
  20 #include "xfs_types.h"
  21 #include "xfs_bit.h"
  22 #include "xfs_log.h"
  23 #include "xfs_inum.h"
  24 #include "xfs_trans.h"
  25 #include "xfs_sb.h"
  26 #include "xfs_ag.h"
  27 #include "xfs_mount.h"
  28 #include "xfs_bmap_btree.h"
  29 #include "xfs_alloc_btree.h"
  30 #include "xfs_ialloc_btree.h"
  31 #include "xfs_dinode.h"
  32 #include "xfs_inode.h"
  33 #include "xfs_inode_item.h"
  34 #include "xfs_btree.h"
  35 #include "xfs_btree_trace.h"
  36 #include "xfs_error.h"
  37 #include "xfs_trace.h"
  38
  39 /*
  40  * Cursor allocation zone.
  41  */
  42 kmem_zone_t     *xfs_btree_cur_zone;
  43
  44 /*
  45  * Btree magic numbers.
  46  */
  47 const __uint32_t xfs_magics[XFS_BTNUM_MAX] = {
  48         XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, XFS_BMAP_MAGIC, XFS_IBT_MAGIC
  49 };
  50
  51
  52 STATIC int                              /* error (0 or EFSCORRUPTED) */
  53 xfs_btree_check_lblock(
  54         struct xfs_btree_cur    *cur,   /* btree cursor */
  55         struct xfs_btree_block  *block, /* btree long form block pointer */
  56         int                     level,  /* level of the btree block */
  57         struct xfs_buf          *bp)    /* buffer for block, if any */
  58 {
  59         int                     lblock_ok; /* block passes checks */
  60         struct xfs_mount        *mp;    /* file system mount point */
  61
  62         mp = cur->bc_mp;
  63         lblock_ok =
  64                 be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
  65                 be16_to_cpu(block->bb_level) == level &&
  66                 be16_to_cpu(block->bb_numrecs) <=
  67                         cur->bc_ops->get_maxrecs(cur, level) &&
  68                 block->bb_u.l.bb_leftsib &&
  69                 (be64_to_cpu(block->bb_u.l.bb_leftsib) == NULLDFSBNO ||
  70                  XFS_FSB_SANITY_CHECK(mp,
  71                         be64_to_cpu(block->bb_u.l.bb_leftsib))) &&
  72                 block->bb_u.l.bb_rightsib &&
  73                 (be64_to_cpu(block->bb_u.l.bb_rightsib) == NULLDFSBNO ||
  74                  XFS_FSB_SANITY_CHECK(mp,
  75                         be64_to_cpu(block->bb_u.l.bb_rightsib)));
  76         if (unlikely(XFS_TEST_ERROR(!lblock_ok, mp,
  77                         XFS_ERRTAG_BTREE_CHECK_LBLOCK,
  78                         XFS_RANDOM_BTREE_CHECK_LBLOCK))) {
  79                 if (bp)
  80                         trace_xfs_btree_corrupt(bp, _RET_IP_);
  81                 XFS_ERROR_REPORT("xfs_btree_check_lblock", XFS_ERRLEVEL_LOW,
  82                                  mp);
  83                 return XFS_ERROR(EFSCORRUPTED);
  84         }
  85         return 0;
  86 }
  87
  88 STATIC int                              /* error (0 or EFSCORRUPTED) */
  89 xfs_btree_check_sblock(
  90         struct xfs_btree_cur    *cur,   /* btree cursor */
  91         struct xfs_btree_block  *block, /* btree short form block pointer */
  92         int                     level,  /* level of the btree block */
  93         struct xfs_buf          *bp)    /* buffer containing block */
  94 {
  95         struct xfs_buf          *agbp;  /* buffer for ag. freespace struct */
  96         struct xfs_agf          *agf;   /* ag. freespace structure */
  97         xfs_agblock_t           agflen; /* native ag. freespace length */
  98         int                     sblock_ok; /* block passes checks */
  99
 100         agbp = cur->bc_private.a.agbp;
 101         agf = XFS_BUF_TO_AGF(agbp);
 102         agflen = be32_to_cpu(agf->agf_length);
 103         sblock_ok =
 104                 be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
 105                 be16_to_cpu(block->bb_level) == level &&
 106                 be16_to_cpu(block->bb_numrecs) <=
 107                         cur->bc_ops->get_maxrecs(cur, level) &&
 108                 (be32_to_cpu(block->bb_u.s.bb_leftsib) == NULLAGBLOCK ||
 109                  be32_to_cpu(block->bb_u.s.bb_leftsib) < agflen) &&
 110                 block->bb_u.s.bb_leftsib &&
 111                 (be32_to_cpu(block->bb_u.s.bb_rightsib) == NULLAGBLOCK ||
 112                  be32_to_cpu(block->bb_u.s.bb_rightsib) < agflen) &&
 113                 block->bb_u.s.bb_rightsib;
 114         if (unlikely(XFS_TEST_ERROR(!sblock_ok, cur->bc_mp,
 115                         XFS_ERRTAG_BTREE_CHECK_SBLOCK,
 116                         XFS_RANDOM_BTREE_CHECK_SBLOCK))) {
 117                 if (bp)
 118                         trace_xfs_btree_corrupt(bp, _RET_IP_);
 119                 XFS_CORRUPTION_ERROR("xfs_btree_check_sblock",
 120                         XFS_ERRLEVEL_LOW, cur->bc_mp, block);
 121                 return XFS_ERROR(EFSCORRUPTED);
 122         }
 123         return 0;
 124 }
 125
 126 /*
 127  * Debug routine: check that block header is ok.
 128  */
 129 int
 130 xfs_btree_check_block(
 131         struct xfs_btree_cur    *cur,   /* btree cursor */
 132         struct xfs_btree_block  *block, /* generic btree block pointer */
 133         int                     level,  /* level of the btree block */
 134         struct xfs_buf          *bp)    /* buffer containing block, if any */
 135 {
 136         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 137                 return xfs_btree_check_lblock(cur, block, level, bp);
 138         else
 139                 return xfs_btree_check_sblock(cur, block, level, bp);
 140 }
 141
 142 /*
 143  * Check that (long) pointer is ok.
 144  */
 145 int                                     /* error (0 or EFSCORRUPTED) */
 146 xfs_btree_check_lptr(
 147         struct xfs_btree_cur    *cur,   /* btree cursor */
 148         xfs_dfsbno_t            bno,    /* btree block disk address */
 149         int                     level)  /* btree block level */
 150 {
 151         XFS_WANT_CORRUPTED_RETURN(
 152                 level > 0 &&
 153                 bno != NULLDFSBNO &&
 154                 XFS_FSB_SANITY_CHECK(cur->bc_mp, bno));
 155         return 0;
 156 }
 157
 158 #ifdef DEBUG
 159 /*
 160  * Check that (short) pointer is ok.
 161  */
 162 STATIC int                              /* error (0 or EFSCORRUPTED) */
 163 xfs_btree_check_sptr(
 164         struct xfs_btree_cur    *cur,   /* btree cursor */
 165         xfs_agblock_t           bno,    /* btree block disk address */
 166         int                     level)  /* btree block level */
 167 {
 168         xfs_agblock_t           agblocks = cur->bc_mp->m_sb.sb_agblocks;
 169
 170         XFS_WANT_CORRUPTED_RETURN(
 171                 level > 0 &&
 172                 bno != NULLAGBLOCK &&
 173                 bno != 0 &&
 174                 bno < agblocks);
 175         return 0;
 176 }
 177
 178 /*
 179  * Check that block ptr is ok.
 180  */
 181 STATIC int                              /* error (0 or EFSCORRUPTED) */
 182 xfs_btree_check_ptr(
 183         struct xfs_btree_cur    *cur,   /* btree cursor */
 184         union xfs_btree_ptr     *ptr,   /* btree block disk address */
 185         int                     index,  /* offset from ptr to check */
 186         int                     level)  /* btree block level */
 187 {
 188         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 189                 return xfs_btree_check_lptr(cur,
 190                                 be64_to_cpu((&ptr->l)[index]), level);
 191         } else {
 192                 return xfs_btree_check_sptr(cur,
 193                                 be32_to_cpu((&ptr->s)[index]), level);
 194         }
 195 }
 196 #endif
 197
 198 /*
 199  * Delete the btree cursor.
 200  */
 201 void
 202 xfs_btree_del_cursor(
 203         xfs_btree_cur_t *cur,           /* btree cursor */
 204         int             error)          /* del because of error */
 205 {
 206         int             i;              /* btree level */
 207
 208         /*
 209          * Clear the buffer pointers, and release the buffers.
 210          * If we're doing this in the face of an error, we
 211          * need to make sure to inspect all of the entries
 212          * in the bc_bufs array for buffers to be unlocked.
 213          * This is because some of the btree code works from
 214          * level n down to 0, and if we get an error along
 215          * the way we won't have initialized all the entries
 216          * down to 0.
 217          */
 218         for (i = 0; i < cur->bc_nlevels; i++) {
 219                 if (cur->bc_bufs[i])
 220                         xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[i]);
 221                 else if (!error)
 222                         break;
 223         }
 224         /*
 225          * Can't free a bmap cursor without having dealt with the
 226          * allocated indirect blocks' accounting.
 227          */
 228         ASSERT(cur->bc_btnum != XFS_BTNUM_BMAP ||
 229                cur->bc_private.b.allocated == 0);
 230         /*
 231          * Free the cursor.
 232          */
 233         kmem_zone_free(xfs_btree_cur_zone, cur);
 234 }
 235
 236 /*
 237  * Duplicate the btree cursor.
 238  * Allocate a new one, copy the record, re-get the buffers.
 239  */
 240 int                                     /* error */
 241 xfs_btree_dup_cursor(
 242         xfs_btree_cur_t *cur,           /* input cursor */
 243         xfs_btree_cur_t **ncur)         /* output cursor */
 244 {
 245         xfs_buf_t       *bp;            /* btree block's buffer pointer */
 246         int             error;          /* error return value */
 247         int             i;              /* level number of btree block */
 248         xfs_mount_t     *mp;            /* mount structure for filesystem */
 249         xfs_btree_cur_t *new;           /* new cursor value */
 250         xfs_trans_t     *tp;            /* transaction pointer, can be NULL */
 251
 252         tp = cur->bc_tp;
 253         mp = cur->bc_mp;
 254
 255         /*
 256          * Allocate a new cursor like the old one.
 257          */
 258         new = cur->bc_ops->dup_cursor(cur);
 259
 260         /*
 261          * Copy the record currently in the cursor.
 262          */
 263         new->bc_rec = cur->bc_rec;
 264
 265         /*
 266          * For each level current, re-get the buffer and copy the ptr value.
 267          */
 268         for (i = 0; i < new->bc_nlevels; i++) {
 269                 new->bc_ptrs[i] = cur->bc_ptrs[i];
 270                 new->bc_ra[i] = cur->bc_ra[i];
 271                 if ((bp = cur->bc_bufs[i])) {
 272                         if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
 273                                 XFS_BUF_ADDR(bp), mp->m_bsize, 0, &bp))) {
 274                                 xfs_btree_del_cursor(new, error);
 275                                 *ncur = NULL;
 276                                 return error;
 277                         }
 278                         new->bc_bufs[i] = bp;
 279                         ASSERT(bp);
 280                         ASSERT(!XFS_BUF_GETERROR(bp));
 281                 } else
 282                         new->bc_bufs[i] = NULL;
 283         }
 284         *ncur = new;
 285         return 0;
 286 }
 287
 288 /*
 289  * XFS btree block layout and addressing:
 290  *
 291  * There are two types of blocks in the btree: leaf and non-leaf blocks.
 292  *
 293  * The leaf record start with a header then followed by records containing
 294  * the values.  A non-leaf block also starts with the same header, and
 295  * then first contains lookup keys followed by an equal number of pointers
 296  * to the btree blocks at the previous level.
 297  *
 298  *              +--------+-------+-------+-------+-------+-------+-------+
 299  * Leaf:        | header | rec 1 | rec 2 | rec 3 | rec 4 | rec 5 | rec N |
 300  *              +--------+-------+-------+-------+-------+-------+-------+
 301  *
 302  *              +--------+-------+-------+-------+-------+-------+-------+
 303  * Non-Leaf:    | header | key 1 | key 2 | key N | ptr 1 | ptr 2 | ptr N |
 304  *              +--------+-------+-------+-------+-------+-------+-------+
 305  *
 306  * The header is called struct xfs_btree_block for reasons better left unknown
 307  * and comes in different versions for short (32bit) and long (64bit) block
 308  * pointers.  The record and key structures are defined by the btree instances
 309  * and opaque to the btree core.  The block pointers are simple disk endian
 310  * integers, available in a short (32bit) and long (64bit) variant.
 311  *
 312  * The helpers below calculate the offset of a given record, key or pointer
 313  * into a btree block (xfs_btree_*_offset) or return a pointer to the given
 314  * record, key or pointer (xfs_btree_*_addr).  Note that all addressing
 315  * inside the btree block is done using indices starting at one, not zero!
 316  */
 317
 318 /*
 319  * Return size of the btree block header for this btree instance.
 320  */
 321 static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur)
 322 {
 323         return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
 324                 XFS_BTREE_LBLOCK_LEN :
 325                 XFS_BTREE_SBLOCK_LEN;
 326 }
 327
 328 /*
 329  * Return size of btree block pointers for this btree instance.
 330  */
 331 static inline size_t xfs_btree_ptr_len(struct xfs_btree_cur *cur)
 332 {
 333         return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
 334                 sizeof(__be64) : sizeof(__be32);
 335 }
 336
 337 /*
 338  * Calculate offset of the n-th record in a btree block.
 339  */
 340 STATIC size_t
 341 xfs_btree_rec_offset(
 342         struct xfs_btree_cur    *cur,
 343         int                     n)
 344 {
 345         return xfs_btree_block_len(cur) +
 346                 (n - 1) * cur->bc_ops->rec_len;
 347 }
 348
 349 /*
 350  * Calculate offset of the n-th key in a btree block.
 351  */
 352 STATIC size_t
 353 xfs_btree_key_offset(
 354         struct xfs_btree_cur    *cur,
 355         int                     n)
 356 {
 357         return xfs_btree_block_len(cur) +
 358                 (n - 1) * cur->bc_ops->key_len;
 359 }
 360
 361 /*
 362  * Calculate offset of the n-th block pointer in a btree block.
 363  */
 364 STATIC size_t
 365 xfs_btree_ptr_offset(
 366         struct xfs_btree_cur    *cur,
 367         int                     n,
 368         int                     level)
 369 {
 370         return xfs_btree_block_len(cur) +
 371                 cur->bc_ops->get_maxrecs(cur, level) * cur->bc_ops->key_len +
 372                 (n - 1) * xfs_btree_ptr_len(cur);
 373 }
 374
 375 /*
 376  * Return a pointer to the n-th record in the btree block.
 377  */
 378 STATIC union xfs_btree_rec *
 379 xfs_btree_rec_addr(
 380         struct xfs_btree_cur    *cur,
 381         int                     n,
 382         struct xfs_btree_block  *block)
 383 {
 384         return (union xfs_btree_rec *)
 385                 ((char *)block + xfs_btree_rec_offset(cur, n));
 386 }
 387
 388 /*
 389  * Return a pointer to the n-th key in the btree block.
 390  */
 391 STATIC union xfs_btree_key *
 392 xfs_btree_key_addr(
 393         struct xfs_btree_cur    *cur,
 394         int                     n,
 395         struct xfs_btree_block  *block)
 396 {
 397         return (union xfs_btree_key *)
 398                 ((char *)block + xfs_btree_key_offset(cur, n));
 399 }
 400
 401 /*
 402  * Return a pointer to the n-th block pointer in the btree block.
 403  */
 404 STATIC union xfs_btree_ptr *
 405 xfs_btree_ptr_addr(
 406         struct xfs_btree_cur    *cur,
 407         int                     n,
 408         struct xfs_btree_block  *block)
 409 {
 410         int                     level = xfs_btree_get_level(block);
 411
 412         ASSERT(block->bb_level != 0);
 413
 414         return (union xfs_btree_ptr *)
 415                 ((char *)block + xfs_btree_ptr_offset(cur, n, level));
 416 }
 417
 418 /*
 419  * Get a the root block which is stored in the inode.
 420  *
 421  * For now this btree implementation assumes the btree root is always
 422  * stored in the if_broot field of an inode fork.
 423  */
 424 STATIC struct xfs_btree_block *
 425 xfs_btree_get_iroot(
 426        struct xfs_btree_cur    *cur)
 427 {
 428        struct xfs_ifork        *ifp;
 429
 430        ifp = XFS_IFORK_PTR(cur->bc_private.b.ip, cur->bc_private.b.whichfork);
 431        return (struct xfs_btree_block *)ifp->if_broot;
 432 }
 433
 434 /*
 435  * Retrieve the block pointer from the cursor at the given level.
 436  * This may be an inode btree root or from a buffer.
 437  */
 438 STATIC struct xfs_btree_block *         /* generic btree block pointer */
 439 xfs_btree_get_block(
 440         struct xfs_btree_cur    *cur,   /* btree cursor */
 441         int                     level,  /* level in btree */
 442         struct xfs_buf          **bpp)  /* buffer containing the block */
 443 {
 444         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
 445             (level == cur->bc_nlevels - 1)) {
 446                 *bpp = NULL;
 447                 return xfs_btree_get_iroot(cur);
 448         }
 449
 450         *bpp = cur->bc_bufs[level];
 451         return XFS_BUF_TO_BLOCK(*bpp);
 452 }
 453
 454 /*
 455  * Get a buffer for the block, return it with no data read.
 456  * Long-form addressing.
 457  */
 458 xfs_buf_t *                             /* buffer for fsbno */
 459 xfs_btree_get_bufl(
 460         xfs_mount_t     *mp,            /* file system mount point */
 461         xfs_trans_t     *tp,            /* transaction pointer */
 462         xfs_fsblock_t   fsbno,          /* file system block number */
 463         uint            lock)           /* lock flags for get_buf */
 464 {
 465         xfs_buf_t       *bp;            /* buffer pointer (return value) */
 466         xfs_daddr_t             d;              /* real disk block address */
 467
 468         ASSERT(fsbno != NULLFSBLOCK);
 469         d = XFS_FSB_TO_DADDR(mp, fsbno);
 470         bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, lock);
 471         ASSERT(bp);
 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(bp);
 496         ASSERT(!XFS_BUF_GETERROR(bp));
 497         return bp;
 498 }
 499
 500 /*
 501  * Check for the cursor referring to the last block at the given level.
 502  */
 503 int                                     /* 1=is last block, 0=not last block */
 504 xfs_btree_islastblock(
 505         xfs_btree_cur_t         *cur,   /* btree cursor */
 506         int                     level)  /* level to check */
 507 {
 508         struct xfs_btree_block  *block; /* generic btree block pointer */
 509         xfs_buf_t               *bp;    /* buffer containing block */
 510
 511         block = xfs_btree_get_block(cur, level, &bp);
 512         xfs_btree_check_block(cur, block, level, bp);
 513         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 514                 return be64_to_cpu(block->bb_u.l.bb_rightsib) == NULLDFSBNO;
 515         else
 516                 return be32_to_cpu(block->bb_u.s.bb_rightsib) == NULLAGBLOCK;
 517 }
 518
 519 /*
 520  * Change the cursor to point to the first record at the given level.
 521  * Other levels are unaffected.
 522  */
 523 STATIC int                              /* success=1, failure=0 */
 524 xfs_btree_firstrec(
 525         xfs_btree_cur_t         *cur,   /* btree cursor */
 526         int                     level)  /* level to change */
 527 {
 528         struct xfs_btree_block  *block; /* generic btree block pointer */
 529         xfs_buf_t               *bp;    /* buffer containing block */
 530
 531         /*
 532          * Get the block pointer for this level.
 533          */
 534         block = xfs_btree_get_block(cur, level, &bp);
 535         xfs_btree_check_block(cur, block, level, bp);
 536         /*
 537          * It's empty, there is no such record.
 538          */
 539         if (!block->bb_numrecs)
 540                 return 0;
 541         /*
 542          * Set the ptr value to 1, that's the first record/key.
 543          */
 544         cur->bc_ptrs[level] = 1;
 545         return 1;
 546 }
 547
 548 /*
 549  * Change the cursor to point to the last record in the current block
 550  * at the given level.  Other levels are unaffected.
 551  */
 552 STATIC int                              /* success=1, failure=0 */
 553 xfs_btree_lastrec(
 554         xfs_btree_cur_t         *cur,   /* btree cursor */
 555         int                     level)  /* level to change */
 556 {
 557         struct xfs_btree_block  *block; /* generic btree block pointer */
 558         xfs_buf_t               *bp;    /* buffer containing block */
 559
 560         /*
 561          * Get the block pointer for this level.
 562          */
 563         block = xfs_btree_get_block(cur, level, &bp);
 564         xfs_btree_check_block(cur, block, level, bp);
 565         /*
 566          * It's empty, there is no such record.
 567          */
 568         if (!block->bb_numrecs)
 569                 return 0;
 570         /*
 571          * Set the ptr value to numrecs, that's the last record/key.
 572          */
 573         cur->bc_ptrs[level] = be16_to_cpu(block->bb_numrecs);
 574         return 1;
 575 }
 576
 577 /*
 578  * Compute first and last byte offsets for the fields given.
 579  * Interprets the offsets table, which contains struct field offsets.
 580  */
 581 void
 582 xfs_btree_offsets(
 583         __int64_t       fields,         /* bitmask of fields */
 584         const short     *offsets,       /* table of field offsets */
 585         int             nbits,          /* number of bits to inspect */
 586         int             *first,         /* output: first byte offset */
 587         int             *last)          /* output: last byte offset */
 588 {
 589         int             i;              /* current bit number */
 590         __int64_t       imask;          /* mask for current bit number */
 591
 592         ASSERT(fields != 0);
 593         /*
 594          * Find the lowest bit, so the first byte offset.
 595          */
 596         for (i = 0, imask = 1LL; ; i++, imask <<= 1) {
 597                 if (imask & fields) {
 598                         *first = offsets[i];
 599                         break;
 600                 }
 601         }
 602         /*
 603          * Find the highest bit, so the last byte offset.
 604          */
 605         for (i = nbits - 1, imask = 1LL << i; ; i--, imask >>= 1) {
 606                 if (imask & fields) {
 607                         *last = offsets[i + 1] - 1;
 608                         break;
 609                 }
 610         }
 611 }
 612
 613 /*
 614  * Get a buffer for the block, return it read in.
 615  * Long-form addressing.
 616  */
 617 int                                     /* error */
 618 xfs_btree_read_bufl(
 619         xfs_mount_t     *mp,            /* file system mount point */
 620         xfs_trans_t     *tp,            /* transaction pointer */
 621         xfs_fsblock_t   fsbno,          /* file system block number */
 622         uint            lock,           /* lock flags for read_buf */
 623         xfs_buf_t       **bpp,          /* buffer for fsbno */
 624         int             refval)         /* ref count value for buffer */
 625 {
 626         xfs_buf_t       *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         if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
 633                         mp->m_bsize, lock, &bp))) {
 634                 return error;
 635         }
 636         ASSERT(!bp || !XFS_BUF_GETERROR(bp));
 637         if (bp != NULL) {
 638                 XFS_BUF_SET_VTYPE_REF(bp, B_FS_MAP, refval);
 639         }
 640         *bpp = bp;
 641         return 0;
 642 }
 643
 644 /*
 645  * Read-ahead the block, don't wait for it, don't return a buffer.
 646  * Long-form addressing.
 647  */
 648 /* ARGSUSED */
 649 void
 650 xfs_btree_reada_bufl(
 651         xfs_mount_t     *mp,            /* file system mount point */
 652         xfs_fsblock_t   fsbno,          /* file system block number */
 653         xfs_extlen_t    count)          /* count of filesystem blocks */
 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);
 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         xfs_mount_t     *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 {
 674         xfs_daddr_t             d;
 675
 676         ASSERT(agno != NULLAGNUMBER);
 677         ASSERT(agbno != NULLAGBLOCK);
 678         d = XFS_AGB_TO_DADDR(mp, agno, agbno);
 679         xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count);
 680 }
 681
 682 STATIC int
 683 xfs_btree_readahead_lblock(
 684         struct xfs_btree_cur    *cur,
 685         int                     lr,
 686         struct xfs_btree_block  *block)
 687 {
 688         int                     rval = 0;
 689         xfs_dfsbno_t            left = be64_to_cpu(block->bb_u.l.bb_leftsib);
 690         xfs_dfsbno_t            right = be64_to_cpu(block->bb_u.l.bb_rightsib);
 691
 692         if ((lr & XFS_BTCUR_LEFTRA) && left != NULLDFSBNO) {
 693                 xfs_btree_reada_bufl(cur->bc_mp, left, 1);
 694                 rval++;
 695         }
 696
 697         if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLDFSBNO) {
 698                 xfs_btree_reada_bufl(cur->bc_mp, right, 1);
 699                 rval++;
 700         }
 701
 702         return rval;
 703 }
 704
 705 STATIC int
 706 xfs_btree_readahead_sblock(
 707         struct xfs_btree_cur    *cur,
 708         int                     lr,
 709         struct xfs_btree_block *block)
 710 {
 711         int                     rval = 0;
 712         xfs_agblock_t           left = be32_to_cpu(block->bb_u.s.bb_leftsib);
 713         xfs_agblock_t           right = be32_to_cpu(block->bb_u.s.bb_rightsib);
 714
 715
 716         if ((lr & XFS_BTCUR_LEFTRA) && left != NULLAGBLOCK) {
 717                 xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
 718                                      left, 1);
 719                 rval++;
 720         }
 721
 722         if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {
 723                 xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
 724                                      right, 1);
 725                 rval++;
 726         }
 727
 728         return rval;
 729 }
 730
 731 /*
 732  * Read-ahead btree blocks, at the given level.
 733  * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
 734  */
 735 STATIC int
 736 xfs_btree_readahead(
 737         struct xfs_btree_cur    *cur,           /* btree cursor */
 738         int                     lev,            /* level in btree */
 739         int                     lr)             /* left/right bits */
 740 {
 741         struct xfs_btree_block  *block;
 742
 743         /*
 744          * No readahead needed if we are at the root level and the
 745          * btree root is stored in the inode.
 746          */
 747         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
 748             (lev == cur->bc_nlevels - 1))
 749                 return 0;
 750
 751         if ((cur->bc_ra[lev] | lr) == cur->bc_ra[lev])
 752                 return 0;
 753
 754         cur->bc_ra[lev] |= lr;
 755         block = XFS_BUF_TO_BLOCK(cur->bc_bufs[lev]);
 756
 757         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 758                 return xfs_btree_readahead_lblock(cur, lr, block);
 759         return xfs_btree_readahead_sblock(cur, lr, block);
 760 }
 761
 762 /*
 763  * Set the buffer for level "lev" in the cursor to bp, releasing
 764  * any previous buffer.
 765  */
 766 STATIC void
 767 xfs_btree_setbuf(
 768         xfs_btree_cur_t         *cur,   /* btree cursor */
 769         int                     lev,    /* level in btree */
 770         xfs_buf_t               *bp)    /* new buffer to set */
 771 {
 772         struct xfs_btree_block  *b;     /* btree block */
 773
 774         if (cur->bc_bufs[lev])
 775                 xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[lev]);
 776         cur->bc_bufs[lev] = bp;
 777         cur->bc_ra[lev] = 0;
 778
 779         b = XFS_BUF_TO_BLOCK(bp);
 780         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 781                 if (be64_to_cpu(b->bb_u.l.bb_leftsib) == NULLDFSBNO)
 782                         cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
 783                 if (be64_to_cpu(b->bb_u.l.bb_rightsib) == NULLDFSBNO)
 784                         cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
 785         } else {
 786                 if (be32_to_cpu(b->bb_u.s.bb_leftsib) == NULLAGBLOCK)
 787                         cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
 788                 if (be32_to_cpu(b->bb_u.s.bb_rightsib) == NULLAGBLOCK)
 789                         cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
 790         }
 791 }
 792
 793 STATIC int
 794 xfs_btree_ptr_is_null(
 795         struct xfs_btree_cur    *cur,
 796         union xfs_btree_ptr     *ptr)
 797 {
 798         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 799                 return be64_to_cpu(ptr->l) == NULLDFSBNO;
 800         else
 801                 return be32_to_cpu(ptr->s) == NULLAGBLOCK;
 802 }
 803
 804 STATIC void
 805 xfs_btree_set_ptr_null(
 806         struct xfs_btree_cur    *cur,
 807         union xfs_btree_ptr     *ptr)
 808 {
 809         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 810                 ptr->l = cpu_to_be64(NULLDFSBNO);
 811         else
 812                 ptr->s = cpu_to_be32(NULLAGBLOCK);
 813 }
 814
 815 /*
 816  * Get/set/init sibling pointers
 817  */
 818 STATIC void
 819 xfs_btree_get_sibling(
 820         struct xfs_btree_cur    *cur,
 821         struct xfs_btree_block  *block,
 822         union xfs_btree_ptr     *ptr,
 823         int                     lr)
 824 {
 825         ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
 826
 827         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 828                 if (lr == XFS_BB_RIGHTSIB)
 829                         ptr->l = block->bb_u.l.bb_rightsib;
 830                 else
 831                         ptr->l = block->bb_u.l.bb_leftsib;
 832         } else {
 833                 if (lr == XFS_BB_RIGHTSIB)
 834                         ptr->s = block->bb_u.s.bb_rightsib;
 835                 else
 836                         ptr->s = block->bb_u.s.bb_leftsib;
 837         }
 838 }
 839
 840 STATIC void
 841 xfs_btree_set_sibling(
 842         struct xfs_btree_cur    *cur,
 843         struct xfs_btree_block  *block,
 844         union xfs_btree_ptr     *ptr,
 845         int                     lr)
 846 {
 847         ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
 848
 849         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 850                 if (lr == XFS_BB_RIGHTSIB)
 851                         block->bb_u.l.bb_rightsib = ptr->l;
 852                 else
 853                         block->bb_u.l.bb_leftsib = ptr->l;
 854         } else {
 855                 if (lr == XFS_BB_RIGHTSIB)
 856                         block->bb_u.s.bb_rightsib = ptr->s;
 857                 else
 858                         block->bb_u.s.bb_leftsib = ptr->s;
 859         }
 860 }
 861
 862 STATIC void
 863 xfs_btree_init_block(
 864         struct xfs_btree_cur    *cur,
 865         int                     level,
 866         int                     numrecs,
 867         struct xfs_btree_block  *new)   /* new block */
 868 {
 869         new->bb_magic = cpu_to_be32(xfs_magics[cur->bc_btnum]);
 870         new->bb_level = cpu_to_be16(level);
 871         new->bb_numrecs = cpu_to_be16(numrecs);
 872
 873         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 874                 new->bb_u.l.bb_leftsib = cpu_to_be64(NULLDFSBNO);
 875                 new->bb_u.l.bb_rightsib = cpu_to_be64(NULLDFSBNO);
 876         } else {
 877                 new->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
 878                 new->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
 879         }
 880 }
 881
 882 /*
 883  * Return true if ptr is the last record in the btree and
 884  * we need to track updateѕ to this record.  The decision
 885  * will be further refined in the update_lastrec method.
 886  */
 887 STATIC int
 888 xfs_btree_is_lastrec(
 889         struct xfs_btree_cur    *cur,
 890         struct xfs_btree_block  *block,
 891         int                     level)
 892 {
 893         union xfs_btree_ptr     ptr;
 894
 895         if (level > 0)
 896                 return 0;
 897         if (!(cur->bc_flags & XFS_BTREE_LASTREC_UPDATE))
 898                 return 0;
 899
 900         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
 901         if (!xfs_btree_ptr_is_null(cur, &ptr))
 902                 return 0;
 903         return 1;
 904 }
 905
 906 STATIC void
 907 xfs_btree_buf_to_ptr(
 908         struct xfs_btree_cur    *cur,
 909         struct xfs_buf          *bp,
 910         union xfs_btree_ptr     *ptr)
 911 {
 912         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 913                 ptr->l = cpu_to_be64(XFS_DADDR_TO_FSB(cur->bc_mp,
 914                                         XFS_BUF_ADDR(bp)));
 915         else {
 916                 ptr->s = cpu_to_be32(xfs_daddr_to_agbno(cur->bc_mp,
 917                                         XFS_BUF_ADDR(bp)));
 918         }
 919 }
 920
 921 STATIC xfs_daddr_t
 922 xfs_btree_ptr_to_daddr(
 923         struct xfs_btree_cur    *cur,
 924         union xfs_btree_ptr     *ptr)
 925 {
 926         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 927                 ASSERT(be64_to_cpu(ptr->l) != NULLDFSBNO);
 928
 929                 return XFS_FSB_TO_DADDR(cur->bc_mp, be64_to_cpu(ptr->l));
 930         } else {
 931                 ASSERT(cur->bc_private.a.agno != NULLAGNUMBER);
 932                 ASSERT(be32_to_cpu(ptr->s) != NULLAGBLOCK);
 933
 934                 return XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_private.a.agno,
 935                                         be32_to_cpu(ptr->s));
 936         }
 937 }
 938
 939 STATIC void
 940 xfs_btree_set_refs(
 941         struct xfs_btree_cur    *cur,
 942         struct xfs_buf          *bp)
 943 {
 944         switch (cur->bc_btnum) {
 945         case XFS_BTNUM_BNO:
 946         case XFS_BTNUM_CNT:
 947                 XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_MAP, XFS_ALLOC_BTREE_REF);
 948                 break;
 949         case XFS_BTNUM_INO:
 950                 XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_INOMAP, XFS_INO_BTREE_REF);
 951                 break;
 952         case XFS_BTNUM_BMAP:
 953                 XFS_BUF_SET_VTYPE_REF(*bpp, B_FS_MAP, XFS_BMAP_BTREE_REF);
 954                 break;
 955         default:
 956                 ASSERT(0);
 957         }
 958 }
 959
 960 STATIC int
 961 xfs_btree_get_buf_block(
 962         struct xfs_btree_cur    *cur,
 963         union xfs_btree_ptr     *ptr,
 964         int                     flags,
 965         struct xfs_btree_block  **block,
 966         struct xfs_buf          **bpp)
 967 {
 968         struct xfs_mount        *mp = cur->bc_mp;
 969         xfs_daddr_t             d;
 970
 971         /* need to sort out how callers deal with failures first */
 972         ASSERT(!(flags & XBF_TRYLOCK));
 973
 974         d = xfs_btree_ptr_to_daddr(cur, ptr);
 975         *bpp = xfs_trans_get_buf(cur->bc_tp, mp->m_ddev_targp, d,
 976                                  mp->m_bsize, flags);
 977
 978         ASSERT(*bpp);
 979         ASSERT(!XFS_BUF_GETERROR(*bpp));
 980
 981         *block = XFS_BUF_TO_BLOCK(*bpp);
 982         return 0;
 983 }
 984
 985 /*
 986  * Read in the buffer at the given ptr and return the buffer and
 987  * the block pointer within the buffer.
 988  */
 989 STATIC int
 990 xfs_btree_read_buf_block(
 991         struct xfs_btree_cur    *cur,
 992         union xfs_btree_ptr     *ptr,
 993         int                     level,
 994         int                     flags,
 995         struct xfs_btree_block  **block,
 996         struct xfs_buf          **bpp)
 997 {
 998         struct xfs_mount        *mp = cur->bc_mp;
 999         xfs_daddr_t             d;
1000         int                     error;
1001
1002         /* need to sort out how callers deal with failures first */
1003         ASSERT(!(flags & XBF_TRYLOCK));
1004
1005         d = xfs_btree_ptr_to_daddr(cur, ptr);
1006         error = xfs_trans_read_buf(mp, cur->bc_tp, mp->m_ddev_targp, d,
1007                                    mp->m_bsize, flags, bpp);
1008         if (error)
1009                 return error;
1010
1011         ASSERT(*bpp != NULL);
1012         ASSERT(!XFS_BUF_GETERROR(*bpp));
1013
1014         xfs_btree_set_refs(cur, *bpp);
1015         *block = XFS_BUF_TO_BLOCK(*bpp);
1016
1017         error = xfs_btree_check_block(cur, *block, level, *bpp);
1018         if (error)
1019                 xfs_trans_brelse(cur->bc_tp, *bpp);
1020         return error;
1021 }
1022
1023 /*
1024  * Copy keys from one btree block to another.
1025  */
1026 STATIC void
1027 xfs_btree_copy_keys(
1028         struct xfs_btree_cur    *cur,
1029         union xfs_btree_key     *dst_key,
1030         union xfs_btree_key     *src_key,
1031         int                     numkeys)
1032 {
1033         ASSERT(numkeys >= 0);
1034         memcpy(dst_key, src_key, numkeys * cur->bc_ops->key_len);
1035 }
1036
1037 /*
1038  * Copy records from one btree block to another.
1039  */
1040 STATIC void
1041 xfs_btree_copy_recs(
1042         struct xfs_btree_cur    *cur,
1043         union xfs_btree_rec     *dst_rec,
1044         union xfs_btree_rec     *src_rec,
1045         int                     numrecs)
1046 {
1047         ASSERT(numrecs >= 0);
1048         memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
1049 }
1050
1051 /*
1052  * Copy block pointers from one btree block to another.
1053  */
1054 STATIC void
1055 xfs_btree_copy_ptrs(
1056         struct xfs_btree_cur    *cur,
1057         union xfs_btree_ptr     *dst_ptr,
1058         union xfs_btree_ptr     *src_ptr,
1059         int                     numptrs)
1060 {
1061         ASSERT(numptrs >= 0);
1062         memcpy(dst_ptr, src_ptr, numptrs * xfs_btree_ptr_len(cur));
1063 }
1064
1065 /*
1066  * Shift keys one index left/right inside a single btree block.
1067  */
1068 STATIC void
1069 xfs_btree_shift_keys(
1070         struct xfs_btree_cur    *cur,
1071         union xfs_btree_key     *key,
1072         int                     dir,
1073         int                     numkeys)
1074 {
1075         char                    *dst_key;
1076
1077         ASSERT(numkeys >= 0);
1078         ASSERT(dir == 1 || dir == -1);
1079
1080         dst_key = (char *)key + (dir * cur->bc_ops->key_len);
1081         memmove(dst_key, key, numkeys * cur->bc_ops->key_len);
1082 }
1083
1084 /*
1085  * Shift records one index left/right inside a single btree block.
1086  */
1087 STATIC void
1088 xfs_btree_shift_recs(
1089         struct xfs_btree_cur    *cur,
1090         union xfs_btree_rec     *rec,
1091         int                     dir,
1092         int                     numrecs)
1093 {
1094         char                    *dst_rec;
1095
1096         ASSERT(numrecs >= 0);
1097         ASSERT(dir == 1 || dir == -1);
1098
1099         dst_rec = (char *)rec + (dir * cur->bc_ops->rec_len);
1100         memmove(dst_rec, rec, numrecs * cur->bc_ops->rec_len);
1101 }
1102
1103 /*
1104  * Shift block pointers one index left/right inside a single btree block.
1105  */
1106 STATIC void
1107 xfs_btree_shift_ptrs(
1108         struct xfs_btree_cur    *cur,
1109         union xfs_btree_ptr     *ptr,
1110         int                     dir,
1111         int                     numptrs)
1112 {
1113         char                    *dst_ptr;
1114
1115         ASSERT(numptrs >= 0);
1116         ASSERT(dir == 1 || dir == -1);
1117
1118         dst_ptr = (char *)ptr + (dir * xfs_btree_ptr_len(cur));
1119         memmove(dst_ptr, ptr, numptrs * xfs_btree_ptr_len(cur));
1120 }
1121
1122 /*
1123  * Log key values from the btree block.
1124  */
1125 STATIC void
1126 xfs_btree_log_keys(
1127         struct xfs_btree_cur    *cur,
1128         struct xfs_buf          *bp,
1129         int                     first,
1130         int                     last)
1131 {
1132         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1133         XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
1134
1135         if (bp) {
1136                 xfs_trans_log_buf(cur->bc_tp, bp,
1137                                   xfs_btree_key_offset(cur, first),
1138                                   xfs_btree_key_offset(cur, last + 1) - 1);
1139         } else {
1140                 xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1141                                 xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1142         }
1143
1144         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1145 }
1146
1147 /*
1148  * Log record values from the btree block.
1149  */
1150 void
1151 xfs_btree_log_recs(
1152         struct xfs_btree_cur    *cur,
1153         struct xfs_buf          *bp,
1154         int                     first,
1155         int                     last)
1156 {
1157         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1158         XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
1159
1160         xfs_trans_log_buf(cur->bc_tp, bp,
1161                           xfs_btree_rec_offset(cur, first),
1162                           xfs_btree_rec_offset(cur, last + 1) - 1);
1163
1164         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1165 }
1166
1167 /*
1168  * Log block pointer fields from a btree block (nonleaf).
1169  */
1170 STATIC void
1171 xfs_btree_log_ptrs(
1172         struct xfs_btree_cur    *cur,   /* btree cursor */
1173         struct xfs_buf          *bp,    /* buffer containing btree block */
1174         int                     first,  /* index of first pointer to log */
1175         int                     last)   /* index of last pointer to log */
1176 {
1177         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1178         XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
1179
1180         if (bp) {
1181                 struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
1182                 int                     level = xfs_btree_get_level(block);
1183
1184                 xfs_trans_log_buf(cur->bc_tp, bp,
1185                                 xfs_btree_ptr_offset(cur, first, level),
1186                                 xfs_btree_ptr_offset(cur, last + 1, level) - 1);
1187         } else {
1188                 xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1189                         xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1190         }
1191
1192         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1193 }
1194
1195 /*
1196  * Log fields from a btree block header.
1197  */
1198 void
1199 xfs_btree_log_block(
1200         struct xfs_btree_cur    *cur,   /* btree cursor */
1201         struct xfs_buf          *bp,    /* buffer containing btree block */
1202         int                     fields) /* mask of fields: XFS_BB_... */
1203 {
1204         int                     first;  /* first byte offset logged */
1205         int                     last;   /* last byte offset logged */
1206         static const short      soffsets[] = {  /* table of offsets (short) */
1207                 offsetof(struct xfs_btree_block, bb_magic),
1208                 offsetof(struct xfs_btree_block, bb_level),
1209                 offsetof(struct xfs_btree_block, bb_numrecs),
1210                 offsetof(struct xfs_btree_block, bb_u.s.bb_leftsib),
1211                 offsetof(struct xfs_btree_block, bb_u.s.bb_rightsib),
1212                 XFS_BTREE_SBLOCK_LEN
1213         };
1214         static const short      loffsets[] = {  /* table of offsets (long) */
1215                 offsetof(struct xfs_btree_block, bb_magic),
1216                 offsetof(struct xfs_btree_block, bb_level),
1217                 offsetof(struct xfs_btree_block, bb_numrecs),
1218                 offsetof(struct xfs_btree_block, bb_u.l.bb_leftsib),
1219                 offsetof(struct xfs_btree_block, bb_u.l.bb_rightsib),
1220                 XFS_BTREE_LBLOCK_LEN
1221         };
1222
1223         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1224         XFS_BTREE_TRACE_ARGBI(cur, bp, fields);
1225
1226         if (bp) {
1227                 xfs_btree_offsets(fields,
1228                                   (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
1229                                         loffsets : soffsets,
1230                                   XFS_BB_NUM_BITS, &first, &last);
1231                 xfs_trans_log_buf(cur->bc_tp, bp, first, last);
1232         } else {
1233                 xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1234                         xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1235         }
1236
1237         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1238 }
1239
1240 /*
1241  * Increment cursor by one record at the level.
1242  * For nonzero levels the leaf-ward information is untouched.
1243  */
1244 int                                             /* error */
1245 xfs_btree_increment(
1246         struct xfs_btree_cur    *cur,
1247         int                     level,
1248         int                     *stat)          /* success/failure */
1249 {
1250         struct xfs_btree_block  *block;
1251         union xfs_btree_ptr     ptr;
1252         struct xfs_buf          *bp;
1253         int                     error;          /* error return value */
1254         int                     lev;
1255
1256         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1257         XFS_BTREE_TRACE_ARGI(cur, level);
1258
1259         ASSERT(level < cur->bc_nlevels);
1260
1261         /* Read-ahead to the right at this level. */
1262         xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
1263
1264         /* Get a pointer to the btree block. */
1265         block = xfs_btree_get_block(cur, level, &bp);
1266
1267 #ifdef DEBUG
1268         error = xfs_btree_check_block(cur, block, level, bp);
1269         if (error)
1270                 goto error0;
1271 #endif
1272
1273         /* We're done if we remain in the block after the increment. */
1274         if (++cur->bc_ptrs[level] <= xfs_btree_get_numrecs(block))
1275                 goto out1;
1276
1277         /* Fail if we just went off the right edge of the tree. */
1278         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1279         if (xfs_btree_ptr_is_null(cur, &ptr))
1280                 goto out0;
1281
1282         XFS_BTREE_STATS_INC(cur, increment);
1283
1284         /*
1285          * March up the tree incrementing pointers.
1286          * Stop when we don't go off the right edge of a block.
1287          */
1288         for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1289                 block = xfs_btree_get_block(cur, lev, &bp);
1290
1291 #ifdef DEBUG
1292                 error = xfs_btree_check_block(cur, block, lev, bp);
1293                 if (error)
1294                         goto error0;
1295 #endif
1296
1297                 if (++cur->bc_ptrs[lev] <= xfs_btree_get_numrecs(block))
1298                         break;
1299
1300                 /* Read-ahead the right block for the next loop. */
1301                 xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);
1302         }
1303
1304         /*
1305          * If we went off the root then we are either seriously
1306          * confused or have the tree root in an inode.
1307          */
1308         if (lev == cur->bc_nlevels) {
1309                 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1310                         goto out0;
1311                 ASSERT(0);
1312                 error = EFSCORRUPTED;
1313                 goto error0;
1314         }
1315         ASSERT(lev < cur->bc_nlevels);
1316
1317         /*
1318          * Now walk back down the tree, fixing up the cursor's buffer
1319          * pointers and key numbers.
1320          */
1321         for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1322                 union xfs_btree_ptr     *ptrp;
1323
1324                 ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
1325                 error = xfs_btree_read_buf_block(cur, ptrp, --lev,
1326                                                         0, &block, &bp);
1327                 if (error)
1328                         goto error0;
1329
1330                 xfs_btree_setbuf(cur, lev, bp);
1331                 cur->bc_ptrs[lev] = 1;
1332         }
1333 out1:
1334         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1335         *stat = 1;
1336         return 0;
1337
1338 out0:
1339         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1340         *stat = 0;
1341         return 0;
1342
1343 error0:
1344         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1345         return error;
1346 }
1347
1348 /*
1349  * Decrement cursor by one record at the level.
1350  * For nonzero levels the leaf-ward information is untouched.
1351  */
1352 int                                             /* error */
1353 xfs_btree_decrement(
1354         struct xfs_btree_cur    *cur,
1355         int                     level,
1356         int                     *stat)          /* success/failure */
1357 {
1358         struct xfs_btree_block  *block;
1359         xfs_buf_t               *bp;
1360         int                     error;          /* error return value */
1361         int                     lev;
1362         union xfs_btree_ptr     ptr;
1363
1364         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1365         XFS_BTREE_TRACE_ARGI(cur, level);
1366
1367         ASSERT(level < cur->bc_nlevels);
1368
1369         /* Read-ahead to the left at this level. */
1370         xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);
1371
1372         /* We're done if we remain in the block after the decrement. */
1373         if (--cur->bc_ptrs[level] > 0)
1374                 goto out1;
1375
1376         /* Get a pointer to the btree block. */
1377         block = xfs_btree_get_block(cur, level, &bp);
1378
1379 #ifdef DEBUG
1380         error = xfs_btree_check_block(cur, block, level, bp);
1381         if (error)
1382                 goto error0;
1383 #endif
1384
1385         /* Fail if we just went off the left edge of the tree. */
1386         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
1387         if (xfs_btree_ptr_is_null(cur, &ptr))
1388                 goto out0;
1389
1390         XFS_BTREE_STATS_INC(cur, decrement);
1391
1392         /*
1393          * March up the tree decrementing pointers.
1394          * Stop when we don't go off the left edge of a block.
1395          */
1396         for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1397                 if (--cur->bc_ptrs[lev] > 0)
1398                         break;
1399                 /* Read-ahead the left block for the next loop. */
1400                 xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);
1401         }
1402
1403         /*
1404          * If we went off the root then we are seriously confused.
1405          * or the root of the tree is in an inode.
1406          */
1407         if (lev == cur->bc_nlevels) {
1408                 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1409                         goto out0;
1410                 ASSERT(0);
1411                 error = EFSCORRUPTED;
1412                 goto error0;
1413         }
1414         ASSERT(lev < cur->bc_nlevels);
1415
1416         /*
1417          * Now walk back down the tree, fixing up the cursor's buffer
1418          * pointers and key numbers.
1419          */
1420         for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1421                 union xfs_btree_ptr     *ptrp;
1422
1423                 ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
1424                 error = xfs_btree_read_buf_block(cur, ptrp, --lev,
1425                                                         0, &block, &bp);
1426                 if (error)
1427                         goto error0;
1428                 xfs_btree_setbuf(cur, lev, bp);
1429                 cur->bc_ptrs[lev] = xfs_btree_get_numrecs(block);
1430         }
1431 out1:
1432         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1433         *stat = 1;
1434         return 0;
1435
1436 out0:
1437         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1438         *stat = 0;
1439         return 0;
1440
1441 error0:
1442         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1443         return error;
1444 }
1445
1446 STATIC int
1447 xfs_btree_lookup_get_block(
1448         struct xfs_btree_cur    *cur,   /* btree cursor */
1449         int                     level,  /* level in the btree */
1450         union xfs_btree_ptr     *pp,    /* ptr to btree block */
1451         struct xfs_btree_block  **blkp) /* return btree block */
1452 {
1453         struct xfs_buf          *bp;    /* buffer pointer for btree block */
1454         int                     error = 0;
1455
1456         /* special case the root block if in an inode */
1457         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1458             (level == cur->bc_nlevels - 1)) {
1459                 *blkp = xfs_btree_get_iroot(cur);
1460                 return 0;
1461         }
1462
1463         /*
1464          * If the old buffer at this level for the disk address we are
1465          * looking for re-use it.
1466          *
1467          * Otherwise throw it away and get a new one.
1468          */
1469         bp = cur->bc_bufs[level];
1470         if (bp && XFS_BUF_ADDR(bp) == xfs_btree_ptr_to_daddr(cur, pp)) {
1471                 *blkp = XFS_BUF_TO_BLOCK(bp);
1472                 return 0;
1473         }
1474
1475         error = xfs_btree_read_buf_block(cur, pp, level, 0, blkp, &bp);
1476         if (error)
1477                 return error;
1478
1479         xfs_btree_setbuf(cur, level, bp);
1480         return 0;
1481 }
1482
1483 /*
1484  * Get current search key.  For level 0 we don't actually have a key
1485  * structure so we make one up from the record.  For all other levels
1486  * we just return the right key.
1487  */
1488 STATIC union xfs_btree_key *
1489 xfs_lookup_get_search_key(
1490         struct xfs_btree_cur    *cur,
1491         int                     level,
1492         int                     keyno,
1493         struct xfs_btree_block  *block,
1494         union xfs_btree_key     *kp)
1495 {
1496         if (level == 0) {
1497                 cur->bc_ops->init_key_from_rec(kp,
1498                                 xfs_btree_rec_addr(cur, keyno, block));
1499                 return kp;
1500         }
1501
1502         return xfs_btree_key_addr(cur, keyno, block);
1503 }
1504
1505 /*
1506  * Lookup the record.  The cursor is made to point to it, based on dir.
1507  * Return 0 if can't find any such record, 1 for success.
1508  */
1509 int                                     /* error */
1510 xfs_btree_lookup(
1511         struct xfs_btree_cur    *cur,   /* btree cursor */
1512         xfs_lookup_t            dir,    /* <=, ==, or >= */
1513         int                     *stat)  /* success/failure */
1514 {
1515         struct xfs_btree_block  *block; /* current btree block */
1516         __int64_t               diff;   /* difference for the current key */
1517         int                     error;  /* error return value */
1518         int                     keyno;  /* current key number */
1519         int                     level;  /* level in the btree */
1520         union xfs_btree_ptr     *pp;    /* ptr to btree block */
1521         union xfs_btree_ptr     ptr;    /* ptr to btree block */
1522
1523         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1524         XFS_BTREE_TRACE_ARGI(cur, dir);
1525
1526         XFS_BTREE_STATS_INC(cur, lookup);
1527
1528         block = NULL;
1529         keyno = 0;
1530
1531         /* initialise start pointer from cursor */
1532         cur->bc_ops->init_ptr_from_cur(cur, &ptr);
1533         pp = &ptr;
1534
1535         /*
1536          * Iterate over each level in the btree, starting at the root.
1537          * For each level above the leaves, find the key we need, based
1538          * on the lookup record, then follow the corresponding block
1539          * pointer down to the next level.
1540          */
1541         for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {
1542                 /* Get the block we need to do the lookup on. */
1543                 error = xfs_btree_lookup_get_block(cur, level, pp, &block);
1544                 if (error)
1545                         goto error0;
1546
1547                 if (diff == 0) {
1548                         /*
1549                          * If we already had a key match at a higher level, we
1550                          * know we need to use the first entry in this block.
1551                          */
1552                         keyno = 1;
1553                 } else {
1554                         /* Otherwise search this block. Do a binary search. */
1555
1556                         int     high;   /* high entry number */
1557                         int     low;    /* low entry number */
1558
1559                         /* Set low and high entry numbers, 1-based. */
1560                         low = 1;
1561                         high = xfs_btree_get_numrecs(block);
1562                         if (!high) {
1563                                 /* Block is empty, must be an empty leaf. */
1564                                 ASSERT(level == 0 && cur->bc_nlevels == 1);
1565
1566                                 cur->bc_ptrs[0] = dir != XFS_LOOKUP_LE;
1567                                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1568                                 *stat = 0;
1569                                 return 0;
1570                         }
1571
1572                         /* Binary search the block. */
1573                         while (low <= high) {
1574                                 union xfs_btree_key     key;
1575                                 union xfs_btree_key     *kp;
1576
1577                                 XFS_BTREE_STATS_INC(cur, compare);
1578
1579                                 /* keyno is average of low and high. */
1580                                 keyno = (low + high) >> 1;
1581
1582                                 /* Get current search key */
1583                                 kp = xfs_lookup_get_search_key(cur, level,
1584                                                 keyno, block, &key);
1585
1586                                 /*
1587                                  * Compute difference to get next direction:
1588                                  *  - less than, move right
1589                                  *  - greater than, move left
1590                                  *  - equal, we're done
1591                                  */
1592                                 diff = cur->bc_ops->key_diff(cur, kp);
1593                                 if (diff < 0)
1594                                         low = keyno + 1;
1595                                 else if (diff > 0)
1596                                         high = keyno - 1;
1597                                 else
1598                                         break;
1599                         }
1600                 }
1601
1602                 /*
1603                  * If there are more levels, set up for the next level
1604                  * by getting the block number and filling in the cursor.
1605                  */
1606                 if (level > 0) {
1607                         /*
1608                          * If we moved left, need the previous key number,
1609                          * unless there isn't one.
1610                          */
1611                         if (diff > 0 && --keyno < 1)
1612                                 keyno = 1;
1613                         pp = xfs_btree_ptr_addr(cur, keyno, block);
1614
1615 #ifdef DEBUG
1616                         error = xfs_btree_check_ptr(cur, pp, 0, level);
1617                         if (error)
1618                                 goto error0;
1619 #endif
1620                         cur->bc_ptrs[level] = keyno;
1621                 }
1622         }
1623
1624         /* Done with the search. See if we need to adjust the results. */
1625         if (dir != XFS_LOOKUP_LE && diff < 0) {
1626                 keyno++;
1627                 /*
1628                  * If ge search and we went off the end of the block, but it's
1629                  * not the last block, we're in the wrong block.
1630                  */
1631                 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1632                 if (dir == XFS_LOOKUP_GE &&
1633                     keyno > xfs_btree_get_numrecs(block) &&
1634                     !xfs_btree_ptr_is_null(cur, &ptr)) {
1635                         int     i;
1636
1637                         cur->bc_ptrs[0] = keyno;
1638                         error = xfs_btree_increment(cur, 0, &i);
1639                         if (error)
1640                                 goto error0;
1641                         XFS_WANT_CORRUPTED_RETURN(i == 1);
1642                         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1643                         *stat = 1;
1644                         return 0;
1645                 }
1646         } else if (dir == XFS_LOOKUP_LE && diff > 0)
1647                 keyno--;
1648         cur->bc_ptrs[0] = keyno;
1649
1650         /* Return if we succeeded or not. */
1651         if (keyno == 0 || keyno > xfs_btree_get_numrecs(block))
1652                 *stat = 0;
1653         else if (dir != XFS_LOOKUP_EQ || diff == 0)
1654                 *stat = 1;
1655         else
1656                 *stat = 0;
1657         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1658         return 0;
1659
1660 error0:
1661         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1662         return error;
1663 }
1664
1665 /*
1666  * Update keys at all levels from here to the root along the cursor's path.
1667  */
1668 STATIC int
1669 xfs_btree_updkey(
1670         struct xfs_btree_cur    *cur,
1671         union xfs_btree_key     *keyp,
1672         int                     level)
1673 {
1674         struct xfs_btree_block  *block;
1675         struct xfs_buf          *bp;
1676         union xfs_btree_key     *kp;
1677         int                     ptr;
1678
1679         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1680         XFS_BTREE_TRACE_ARGIK(cur, level, keyp);
1681
1682         ASSERT(!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) || level >= 1);
1683
1684         /*
1685          * Go up the tree from this level toward the root.
1686          * At each level, update the key value to the value input.
1687          * Stop when we reach a level where the cursor isn't pointing
1688          * at the first entry in the block.
1689          */
1690         for (ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
1691 #ifdef DEBUG
1692                 int             error;
1693 #endif
1694                 block = xfs_btree_get_block(cur, level, &bp);
1695 #ifdef DEBUG
1696                 error = xfs_btree_check_block(cur, block, level, bp);
1697                 if (error) {
1698                         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1699                         return error;
1700                 }
1701 #endif
1702                 ptr = cur->bc_ptrs[level];
1703                 kp = xfs_btree_key_addr(cur, ptr, block);
1704                 xfs_btree_copy_keys(cur, kp, keyp, 1);
1705                 xfs_btree_log_keys(cur, bp, ptr, ptr);
1706         }
1707
1708         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1709         return 0;
1710 }
1711
1712 /*
1713  * Update the record referred to by cur to the value in the
1714  * given record. This either works (return 0) or gets an
1715  * EFSCORRUPTED error.
1716  */
1717 int
1718 xfs_btree_update(
1719         struct xfs_btree_cur    *cur,
1720         union xfs_btree_rec     *rec)
1721 {
1722         struct xfs_btree_block  *block;
1723         struct xfs_buf          *bp;
1724         int                     error;
1725         int                     ptr;
1726         union xfs_btree_rec     *rp;
1727
1728         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1729         XFS_BTREE_TRACE_ARGR(cur, rec);
1730
1731         /* Pick up the current block. */
1732         block = xfs_btree_get_block(cur, 0, &bp);
1733
1734 #ifdef DEBUG
1735         error = xfs_btree_check_block(cur, block, 0, bp);
1736         if (error)
1737                 goto error0;
1738 #endif
1739         /* Get the address of the rec to be updated. */
1740         ptr = cur->bc_ptrs[0];
1741         rp = xfs_btree_rec_addr(cur, ptr, block);
1742
1743         /* Fill in the new contents and log them. */
1744         xfs_btree_copy_recs(cur, rp, rec, 1);
1745         xfs_btree_log_recs(cur, bp, ptr, ptr);
1746
1747         /*
1748          * If we are tracking the last record in the tree and
1749          * we are at the far right edge of the tree, update it.
1750          */
1751         if (xfs_btree_is_lastrec(cur, block, 0)) {
1752                 cur->bc_ops->update_lastrec(cur, block, rec,
1753                                             ptr, LASTREC_UPDATE);
1754         }
1755
1756         /* Updating first rec in leaf. Pass new key value up to our parent. */
1757         if (ptr == 1) {
1758                 union xfs_btree_key     key;
1759
1760                 cur->bc_ops->init_key_from_rec(&key, rec);
1761                 error = xfs_btree_updkey(cur, &key, 1);
1762                 if (error)
1763                         goto error0;
1764         }
1765
1766         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1767         return 0;
1768
1769 error0:
1770         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1771         return error;
1772 }
1773
1774 /*
1775  * Move 1 record left from cur/level if possible.
1776  * Update cur to reflect the new path.
1777  */
1778 STATIC int                                      /* error */
1779 xfs_btree_lshift(
1780         struct xfs_btree_cur    *cur,
1781         int                     level,
1782         int                     *stat)          /* success/failure */
1783 {
1784         union xfs_btree_key     key;            /* btree key */
1785         struct xfs_buf          *lbp;           /* left buffer pointer */
1786         struct xfs_btree_block  *left;          /* left btree block */
1787         int                     lrecs;          /* left record count */
1788         struct xfs_buf          *rbp;           /* right buffer pointer */
1789         struct xfs_btree_block  *right;         /* right btree block */
1790         int                     rrecs;          /* right record count */
1791         union xfs_btree_ptr     lptr;           /* left btree pointer */
1792         union xfs_btree_key     *rkp = NULL;    /* right btree key */
1793         union xfs_btree_ptr     *rpp = NULL;    /* right address pointer */
1794         union xfs_btree_rec     *rrp = NULL;    /* right record pointer */
1795         int                     error;          /* error return value */
1796
1797         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1798         XFS_BTREE_TRACE_ARGI(cur, level);
1799
1800         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1801             level == cur->bc_nlevels - 1)
1802                 goto out0;
1803
1804         /* Set up variables for this block as "right". */
1805         right = xfs_btree_get_block(cur, level, &rbp);
1806
1807 #ifdef DEBUG
1808         error = xfs_btree_check_block(cur, right, level, rbp);
1809         if (error)
1810                 goto error0;
1811 #endif
1812
1813         /* If we've got no left sibling then we can't shift an entry left. */
1814         xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
1815         if (xfs_btree_ptr_is_null(cur, &lptr))
1816                 goto out0;
1817
1818         /*
1819          * If the cursor entry is the one that would be moved, don't
1820          * do it... it's too complicated.
1821          */
1822         if (cur->bc_ptrs[level] <= 1)
1823                 goto out0;
1824
1825         /* Set up the left neighbor as "left". */
1826         error = xfs_btree_read_buf_block(cur, &lptr, level, 0, &left, &lbp);
1827         if (error)
1828                 goto error0;
1829
1830         /* If it's full, it can't take another entry. */
1831         lrecs = xfs_btree_get_numrecs(left);
1832         if (lrecs == cur->bc_ops->get_maxrecs(cur, level))
1833                 goto out0;
1834
1835         rrecs = xfs_btree_get_numrecs(right);
1836
1837         /*
1838          * We add one entry to the left side and remove one for the right side.
1839          * Account for it here, the changes will be updated on disk and logged
1840          * later.
1841          */
1842         lrecs++;
1843         rrecs--;
1844
1845         XFS_BTREE_STATS_INC(cur, lshift);
1846         XFS_BTREE_STATS_ADD(cur, moves, 1);
1847
1848         /*
1849          * If non-leaf, copy a key and a ptr to the left block.
1850          * Log the changes to the left block.
1851          */
1852         if (level > 0) {
1853                 /* It's a non-leaf.  Move keys and pointers. */
1854                 union xfs_btree_key     *lkp;   /* left btree key */
1855                 union xfs_btree_ptr     *lpp;   /* left address pointer */
1856
1857                 lkp = xfs_btree_key_addr(cur, lrecs, left);
1858                 rkp = xfs_btree_key_addr(cur, 1, right);
1859
1860                 lpp = xfs_btree_ptr_addr(cur, lrecs, left);
1861                 rpp = xfs_btree_ptr_addr(cur, 1, right);
1862 #ifdef DEBUG
1863                 error = xfs_btree_check_ptr(cur, rpp, 0, level);
1864                 if (error)
1865                         goto error0;
1866 #endif
1867                 xfs_btree_copy_keys(cur, lkp, rkp, 1);
1868                 xfs_btree_copy_ptrs(cur, lpp, rpp, 1);
1869
1870                 xfs_btree_log_keys(cur, lbp, lrecs, lrecs);
1871                 xfs_btree_log_ptrs(cur, lbp, lrecs, lrecs);
1872
1873                 ASSERT(cur->bc_ops->keys_inorder(cur,
1874                         xfs_btree_key_addr(cur, lrecs - 1, left), lkp));
1875         } else {
1876                 /* It's a leaf.  Move records.  */
1877                 union xfs_btree_rec     *lrp;   /* left record pointer */
1878
1879                 lrp = xfs_btree_rec_addr(cur, lrecs, left);
1880                 rrp = xfs_btree_rec_addr(cur, 1, right);
1881
1882                 xfs_btree_copy_recs(cur, lrp, rrp, 1);
1883                 xfs_btree_log_recs(cur, lbp, lrecs, lrecs);
1884
1885                 ASSERT(cur->bc_ops->recs_inorder(cur,
1886                         xfs_btree_rec_addr(cur, lrecs - 1, left), lrp));
1887         }
1888
1889         xfs_btree_set_numrecs(left, lrecs);
1890         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
1891
1892         xfs_btree_set_numrecs(right, rrecs);
1893         xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
1894
1895         /*
1896          * Slide the contents of right down one entry.
1897          */
1898         XFS_BTREE_STATS_ADD(cur, moves, rrecs - 1);
1899         if (level > 0) {
1900                 /* It's a nonleaf. operate on keys and ptrs */
1901 #ifdef DEBUG
1902                 int                     i;              /* loop index */
1903
1904                 for (i = 0; i < rrecs; i++) {
1905                         error = xfs_btree_check_ptr(cur, rpp, i + 1, level);
1906                         if (error)
1907                                 goto error0;
1908                 }
1909 #endif
1910                 xfs_btree_shift_keys(cur,
1911                                 xfs_btree_key_addr(cur, 2, right),
1912                                 -1, rrecs);
1913                 xfs_btree_shift_ptrs(cur,
1914                                 xfs_btree_ptr_addr(cur, 2, right),
1915                                 -1, rrecs);
1916
1917                 xfs_btree_log_keys(cur, rbp, 1, rrecs);
1918                 xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
1919         } else {
1920                 /* It's a leaf. operate on records */
1921                 xfs_btree_shift_recs(cur,
1922                         xfs_btree_rec_addr(cur, 2, right),
1923                         -1, rrecs);
1924                 xfs_btree_log_recs(cur, rbp, 1, rrecs);
1925
1926                 /*
1927                  * If it's the first record in the block, we'll need a key
1928                  * structure to pass up to the next level (updkey).
1929                  */
1930                 cur->bc_ops->init_key_from_rec(&key,
1931                         xfs_btree_rec_addr(cur, 1, right));
1932                 rkp = &key;
1933         }
1934
1935         /* Update the parent key values of right. */
1936         error = xfs_btree_updkey(cur, rkp, level + 1);
1937         if (error)
1938                 goto error0;
1939
1940         /* Slide the cursor value left one. */
1941         cur->bc_ptrs[level]--;
1942
1943         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1944         *stat = 1;
1945         return 0;
1946
1947 out0:
1948         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1949         *stat = 0;
1950         return 0;
1951
1952 error0:
1953         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1954         return error;
1955 }
1956
1957 /*
1958  * Move 1 record right from cur/level if possible.
1959  * Update cur to reflect the new path.
1960  */
1961 STATIC int                                      /* error */
1962 xfs_btree_rshift(
1963         struct xfs_btree_cur    *cur,
1964         int                     level,
1965         int                     *stat)          /* success/failure */
1966 {
1967         union xfs_btree_key     key;            /* btree key */
1968         struct xfs_buf          *lbp;           /* left buffer pointer */
1969         struct xfs_btree_block  *left;          /* left btree block */
1970         struct xfs_buf          *rbp;           /* right buffer pointer */
1971         struct xfs_btree_block  *right;         /* right btree block */
1972         struct xfs_btree_cur    *tcur;          /* temporary btree cursor */
1973         union xfs_btree_ptr     rptr;           /* right block pointer */
1974         union xfs_btree_key     *rkp;           /* right btree key */
1975         int                     rrecs;          /* right record count */
1976         int                     lrecs;          /* left record count */
1977         int                     error;          /* error return value */
1978         int                     i;              /* loop counter */
1979
1980         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1981         XFS_BTREE_TRACE_ARGI(cur, level);
1982
1983         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1984             (level == cur->bc_nlevels - 1))
1985                 goto out0;
1986
1987         /* Set up variables for this block as "left". */
1988         left = xfs_btree_get_block(cur, level, &lbp);
1989
1990 #ifdef DEBUG
1991         error = xfs_btree_check_block(cur, left, level, lbp);
1992         if (error)
1993                 goto error0;
1994 #endif
1995
1996         /* If we've got no right sibling then we can't shift an entry right. */
1997         xfs_btree_get_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
1998         if (xfs_btree_ptr_is_null(cur, &rptr))
1999                 goto out0;
2000
2001         /*
2002          * If the cursor entry is the one that would be moved, don't
2003          * do it... it's too complicated.
2004          */
2005         lrecs = xfs_btree_get_numrecs(left);
2006         if (cur->bc_ptrs[level] >= lrecs)
2007                 goto out0;
2008
2009         /* Set up the right neighbor as "right". */
2010         error = xfs_btree_read_buf_block(cur, &rptr, level, 0, &right, &rbp);
2011         if (error)
2012                 goto error0;
2013
2014         /* If it's full, it can't take another entry. */
2015         rrecs = xfs_btree_get_numrecs(right);
2016         if (rrecs == cur->bc_ops->get_maxrecs(cur, level))
2017                 goto out0;
2018
2019         XFS_BTREE_STATS_INC(cur, rshift);
2020         XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2021
2022         /*
2023          * Make a hole at the start of the right neighbor block, then
2024          * copy the last left block entry to the hole.
2025          */
2026         if (level > 0) {
2027                 /* It's a nonleaf. make a hole in the keys and ptrs */
2028                 union xfs_btree_key     *lkp;
2029                 union xfs_btree_ptr     *lpp;
2030                 union xfs_btree_ptr     *rpp;
2031
2032                 lkp = xfs_btree_key_addr(cur, lrecs, left);
2033                 lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2034                 rkp = xfs_btree_key_addr(cur, 1, right);
2035                 rpp = xfs_btree_ptr_addr(cur, 1, right);
2036
2037 #ifdef DEBUG
2038                 for (i = rrecs - 1; i >= 0; i--) {
2039                         error = xfs_btree_check_ptr(cur, rpp, i, level);
2040                         if (error)
2041                                 goto error0;
2042                 }
2043 #endif
2044
2045                 xfs_btree_shift_keys(cur, rkp, 1, rrecs);
2046                 xfs_btree_shift_ptrs(cur, rpp, 1, rrecs);
2047
2048 #ifdef DEBUG
2049                 error = xfs_btree_check_ptr(cur, lpp, 0, level);
2050                 if (error)
2051                         goto error0;
2052 #endif
2053
2054                 /* Now put the new data in, and log it. */
2055                 xfs_btree_copy_keys(cur, rkp, lkp, 1);
2056                 xfs_btree_copy_ptrs(cur, rpp, lpp, 1);
2057
2058                 xfs_btree_log_keys(cur, rbp, 1, rrecs + 1);
2059                 xfs_btree_log_ptrs(cur, rbp, 1, rrecs + 1);
2060
2061                 ASSERT(cur->bc_ops->keys_inorder(cur, rkp,
2062                         xfs_btree_key_addr(cur, 2, right)));
2063         } else {
2064                 /* It's a leaf. make a hole in the records */
2065                 union xfs_btree_rec     *lrp;
2066                 union xfs_btree_rec     *rrp;
2067
2068                 lrp = xfs_btree_rec_addr(cur, lrecs, left);
2069                 rrp = xfs_btree_rec_addr(cur, 1, right);
2070
2071                 xfs_btree_shift_recs(cur, rrp, 1, rrecs);
2072
2073                 /* Now put the new data in, and log it. */
2074                 xfs_btree_copy_recs(cur, rrp, lrp, 1);
2075                 xfs_btree_log_recs(cur, rbp, 1, rrecs + 1);
2076
2077                 cur->bc_ops->init_key_from_rec(&key, rrp);
2078                 rkp = &key;
2079
2080                 ASSERT(cur->bc_ops->recs_inorder(cur, rrp,
2081                         xfs_btree_rec_addr(cur, 2, right)));
2082         }
2083
2084         /*
2085          * Decrement and log left's numrecs, bump and log right's numrecs.
2086          */
2087         xfs_btree_set_numrecs(left, --lrecs);
2088         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2089
2090         xfs_btree_set_numrecs(right, ++rrecs);
2091         xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2092
2093         /*
2094          * Using a temporary cursor, update the parent key values of the
2095          * block on the right.
2096          */
2097         error = xfs_btree_dup_cursor(cur, &tcur);
2098         if (error)
2099                 goto error0;
2100         i = xfs_btree_lastrec(tcur, level);
2101         XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
2102
2103         error = xfs_btree_increment(tcur, level, &i);
2104         if (error)
2105                 goto error1;
2106
2107         error = xfs_btree_updkey(tcur, rkp, level + 1);
2108         if (error)
2109                 goto error1;
2110
2111         xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2112
2113         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2114         *stat = 1;
2115         return 0;
2116
2117 out0:
2118         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2119         *stat = 0;
2120         return 0;
2121
2122 error0:
2123         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2124         return error;
2125
2126 error1:
2127         XFS_BTREE_TRACE_CURSOR(tcur, XBT_ERROR);
2128         xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2129         return error;
2130 }
2131
2132 /*
2133  * Split cur/level block in half.
2134  * Return new block number and the key to its first
2135  * record (to be inserted into parent).
2136  */
2137 STATIC int                                      /* error */
2138 xfs_btree_split(
2139         struct xfs_btree_cur    *cur,
2140         int                     level,
2141         union xfs_btree_ptr     *ptrp,
2142         union xfs_btree_key     *key,
2143         struct xfs_btree_cur    **curp,
2144         int                     *stat)          /* success/failure */
2145 {
2146         union xfs_btree_ptr     lptr;           /* left sibling block ptr */
2147         struct xfs_buf          *lbp;           /* left buffer pointer */
2148         struct xfs_btree_block  *left;          /* left btree block */
2149         union xfs_btree_ptr     rptr;           /* right sibling block ptr */
2150         struct xfs_buf          *rbp;           /* right buffer pointer */
2151         struct xfs_btree_block  *right;         /* right btree block */
2152         union xfs_btree_ptr     rrptr;          /* right-right sibling ptr */
2153         struct xfs_buf          *rrbp;          /* right-right buffer pointer */
2154         struct xfs_btree_block  *rrblock;       /* right-right btree block */
2155         int                     lrecs;
2156         int                     rrecs;
2157         int                     src_index;
2158         int                     error;          /* error return value */
2159 #ifdef DEBUG
2160         int                     i;
2161 #endif
2162
2163         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2164         XFS_BTREE_TRACE_ARGIPK(cur, level, *ptrp, key);
2165
2166         XFS_BTREE_STATS_INC(cur, split);
2167
2168         /* Set up left block (current one). */
2169         left = xfs_btree_get_block(cur, level, &lbp);
2170
2171 #ifdef DEBUG
2172         error = xfs_btree_check_block(cur, left, level, lbp);
2173         if (error)
2174                 goto error0;
2175 #endif
2176
2177         xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2178
2179         /* Allocate the new block. If we can't do it, we're toast. Give up. */
2180         error = cur->bc_ops->alloc_block(cur, &lptr, &rptr, 1, stat);
2181         if (error)
2182                 goto error0;
2183         if (*stat == 0)
2184                 goto out0;
2185         XFS_BTREE_STATS_INC(cur, alloc);
2186
2187         /* Set up the new block as "right". */
2188         error = xfs_btree_get_buf_block(cur, &rptr, 0, &right, &rbp);
2189         if (error)
2190                 goto error0;
2191
2192         /* Fill in the btree header for the new right block. */
2193         xfs_btree_init_block(cur, xfs_btree_get_level(left), 0, right);
2194
2195         /*
2196          * Split the entries between the old and the new block evenly.
2197          * Make sure that if there's an odd number of entries now, that
2198          * each new block will have the same number of entries.
2199          */
2200         lrecs = xfs_btree_get_numrecs(left);
2201         rrecs = lrecs / 2;
2202         if ((lrecs & 1) && cur->bc_ptrs[level] <= rrecs + 1)
2203                 rrecs++;
2204         src_index = (lrecs - rrecs + 1);
2205
2206         XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2207
2208         /*
2209          * Copy btree block entries from the left block over to the
2210          * new block, the right. Update the right block and log the
2211          * changes.
2212          */
2213         if (level > 0) {
2214                 /* It's a non-leaf.  Move keys and pointers. */
2215                 union xfs_btree_key     *lkp;   /* left btree key */
2216                 union xfs_btree_ptr     *lpp;   /* left address pointer */
2217                 union xfs_btree_key     *rkp;   /* right btree key */
2218                 union xfs_btree_ptr     *rpp;   /* right address pointer */
2219
2220                 lkp = xfs_btree_key_addr(cur, src_index, left);
2221                 lpp = xfs_btree_ptr_addr(cur, src_index, left);
2222                 rkp = xfs_btree_key_addr(cur, 1, right);
2223                 rpp = xfs_btree_ptr_addr(cur, 1, right);
2224
2225 #ifdef DEBUG
2226                 for (i = src_index; i < rrecs; i++) {
2227                         error = xfs_btree_check_ptr(cur, lpp, i, level);
2228                         if (error)
2229                                 goto error0;
2230                 }
2231 #endif
2232
2233                 xfs_btree_copy_keys(cur, rkp, lkp, rrecs);
2234                 xfs_btree_copy_ptrs(cur, rpp, lpp, rrecs);
2235
2236                 xfs_btree_log_keys(cur, rbp, 1, rrecs);
2237                 xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2238
2239                 /* Grab the keys to the entries moved to the right block */
2240                 xfs_btree_copy_keys(cur, key, rkp, 1);
2241         } else {
2242                 /* It's a leaf.  Move records.  */
2243                 union xfs_btree_rec     *lrp;   /* left record pointer */
2244                 union xfs_btree_rec     *rrp;   /* right record pointer */
2245
2246                 lrp = xfs_btree_rec_addr(cur, src_index, left);
2247                 rrp = xfs_btree_rec_addr(cur, 1, right);
2248
2249                 xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
2250                 xfs_btree_log_recs(cur, rbp, 1, rrecs);
2251
2252                 cur->bc_ops->init_key_from_rec(key,
2253                         xfs_btree_rec_addr(cur, 1, right));
2254         }
2255
2256
2257         /*
2258          * Find the left block number by looking in the buffer.
2259          * Adjust numrecs, sibling pointers.
2260          */
2261         xfs_btree_get_sibling(cur, left, &rrptr, XFS_BB_RIGHTSIB);
2262         xfs_btree_set_sibling(cur, right, &rrptr, XFS_BB_RIGHTSIB);
2263         xfs_btree_set_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2264         xfs_btree_set_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2265
2266         lrecs -= rrecs;
2267         xfs_btree_set_numrecs(left, lrecs);
2268         xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
2269
2270         xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
2271         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
2272
2273         /*
2274          * If there's a block to the new block's right, make that block
2275          * point back to right instead of to left.
2276          */
2277         if (!xfs_btree_ptr_is_null(cur, &rrptr)) {
2278                 error = xfs_btree_read_buf_block(cur, &rrptr, level,
2279                                                         0, &rrblock, &rrbp);
2280                 if (error)
2281                         goto error0;
2282                 xfs_btree_set_sibling(cur, rrblock, &rptr, XFS_BB_LEFTSIB);
2283                 xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
2284         }
2285         /*
2286          * If the cursor is really in the right block, move it there.
2287          * If it's just pointing past the last entry in left, then we'll
2288          * insert there, so don't change anything in that case.
2289          */
2290         if (cur->bc_ptrs[level] > lrecs + 1) {
2291                 xfs_btree_setbuf(cur, level, rbp);
2292                 cur->bc_ptrs[level] -= lrecs;
2293         }
2294         /*
2295          * If there are more levels, we'll need another cursor which refers
2296          * the right block, no matter where this cursor was.
2297          */
2298         if (level + 1 < cur->bc_nlevels) {
2299                 error = xfs_btree_dup_cursor(cur, curp);
2300                 if (error)
2301                         goto error0;
2302                 (*curp)->bc_ptrs[level + 1]++;
2303         }
2304         *ptrp = rptr;
2305         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2306         *stat = 1;
2307         return 0;
2308 out0:
2309         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2310         *stat = 0;
2311         return 0;
2312
2313 error0:
2314         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2315         return error;
2316 }
2317
2318 /*
2319  * Copy the old inode root contents into a real block and make the
2320  * broot point to it.
2321  */
2322 int                                             /* error */
2323 xfs_btree_new_iroot(
2324         struct xfs_btree_cur    *cur,           /* btree cursor */
2325         int                     *logflags,      /* logging flags for inode */
2326         int                     *stat)          /* return status - 0 fail */
2327 {
2328         struct xfs_buf          *cbp;           /* buffer for cblock */
2329         struct xfs_btree_block  *block;         /* btree block */
2330         struct xfs_btree_block  *cblock;        /* child btree block */
2331         union xfs_btree_key     *ckp;           /* child key pointer */
2332         union xfs_btree_ptr     *cpp;           /* child ptr pointer */
2333         union xfs_btree_key     *kp;            /* pointer to btree key */
2334         union xfs_btree_ptr     *pp;            /* pointer to block addr */
2335         union xfs_btree_ptr     nptr;           /* new block addr */
2336         int                     level;          /* btree level */
2337         int                     error;          /* error return code */
2338 #ifdef DEBUG
2339         int                     i;              /* loop counter */
2340 #endif
2341
2342         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2343         XFS_BTREE_STATS_INC(cur, newroot);
2344
2345         ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
2346
2347         level = cur->bc_nlevels - 1;
2348
2349         block = xfs_btree_get_iroot(cur);
2350         pp = xfs_btree_ptr_addr(cur, 1, block);
2351
2352         /* Allocate the new block. If we can't do it, we're toast. Give up. */
2353         error = cur->bc_ops->alloc_block(cur, pp, &nptr, 1, stat);
2354         if (error)
2355                 goto error0;
2356         if (*stat == 0) {
2357                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2358                 return 0;
2359         }
2360         XFS_BTREE_STATS_INC(cur, alloc);
2361
2362         /* Copy the root into a real block. */
2363         error = xfs_btree_get_buf_block(cur, &nptr, 0, &cblock, &cbp);
2364         if (error)
2365                 goto error0;
2366
2367         memcpy(cblock, block, xfs_btree_block_len(cur));
2368
2369         be16_add_cpu(&block->bb_level, 1);
2370         xfs_btree_set_numrecs(block, 1);
2371         cur->bc_nlevels++;
2372         cur->bc_ptrs[level + 1] = 1;
2373
2374         kp = xfs_btree_key_addr(cur, 1, block);
2375         ckp = xfs_btree_key_addr(cur, 1, cblock);
2376         xfs_btree_copy_keys(cur, ckp, kp, xfs_btree_get_numrecs(cblock));
2377
2378         cpp = xfs_btree_ptr_addr(cur, 1, cblock);
2379 #ifdef DEBUG
2380         for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
2381                 error = xfs_btree_check_ptr(cur, pp, i, level);
2382                 if (error)
2383                         goto error0;
2384         }
2385 #endif
2386         xfs_btree_copy_ptrs(cur, cpp, pp, xfs_btree_get_numrecs(cblock));
2387
2388 #ifdef DEBUG
2389         error = xfs_btree_check_ptr(cur, &nptr, 0, level);
2390         if (error)
2391                 goto error0;
2392 #endif
2393         xfs_btree_copy_ptrs(cur, pp, &nptr, 1);
2394
2395         xfs_iroot_realloc(cur->bc_private.b.ip,
2396                           1 - xfs_btree_get_numrecs(cblock),
2397                           cur->bc_private.b.whichfork);
2398
2399         xfs_btree_setbuf(cur, level, cbp);
2400
2401         /*
2402          * Do all this logging at the end so that
2403          * the root is at the right level.
2404          */
2405         xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
2406         xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
2407         xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
2408
2409         *logflags |=
2410                 XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_private.b.whichfork);
2411         *stat = 1;
2412         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2413         return 0;
2414 error0:
2415         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2416         return error;
2417 }
2418
2419 /*
2420  * Allocate a new root block, fill it in.
2421  */
2422 STATIC int                              /* error */
2423 xfs_btree_new_root(
2424         struct xfs_btree_cur    *cur,   /* btree cursor */
2425         int                     *stat)  /* success/failure */
2426 {
2427         struct xfs_btree_block  *block; /* one half of the old root block */
2428         struct xfs_buf          *bp;    /* buffer containing block */
2429         int                     error;  /* error return value */
2430         struct xfs_buf          *lbp;   /* left buffer pointer */
2431         struct xfs_btree_block  *left;  /* left btree block */
2432         struct xfs_buf          *nbp;   /* new (root) buffer */
2433         struct xfs_btree_block  *new;   /* new (root) btree block */
2434         int                     nptr;   /* new value for key index, 1 or 2 */
2435         struct xfs_buf          *rbp;   /* right buffer pointer */
2436         struct xfs_btree_block  *right; /* right btree block */
2437         union xfs_btree_ptr     rptr;
2438         union xfs_btree_ptr     lptr;
2439
2440         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2441         XFS_BTREE_STATS_INC(cur, newroot);
2442
2443         /* initialise our start point from the cursor */
2444         cur->bc_ops->init_ptr_from_cur(cur, &rptr);
2445
2446         /* Allocate the new block. If we can't do it, we're toast. Give up. */
2447         error = cur->bc_ops->alloc_block(cur, &rptr, &lptr, 1, stat);
2448         if (error)
2449                 goto error0;
2450         if (*stat == 0)
2451                 goto out0;
2452         XFS_BTREE_STATS_INC(cur, alloc);
2453
2454         /* Set up the new block. */
2455         error = xfs_btree_get_buf_block(cur, &lptr, 0, &new, &nbp);
2456         if (error)
2457                 goto error0;
2458
2459         /* Set the root in the holding structure  increasing the level by 1. */
2460         cur->bc_ops->set_root(cur, &lptr, 1);
2461
2462         /*
2463          * At the previous root level there are now two blocks: the old root,
2464          * and the new block generated when it was split.  We don't know which
2465          * one the cursor is pointing at, so we set up variables "left" and
2466          * "right" for each case.
2467          */
2468         block = xfs_btree_get_block(cur, cur->bc_nlevels - 1, &bp);
2469
2470 #ifdef DEBUG
2471         error = xfs_btree_check_block(cur, block, cur->bc_nlevels - 1, bp);
2472         if (error)
2473                 goto error0;
2474 #endif
2475
2476         xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
2477         if (!xfs_btree_ptr_is_null(cur, &rptr)) {
2478                 /* Our block is left, pick up the right block. */
2479                 lbp = bp;
2480                 xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2481                 left = block;
2482                 error = xfs_btree_read_buf_block(cur, &rptr,
2483                                         cur->bc_nlevels - 1, 0, &right, &rbp);
2484                 if (error)
2485                         goto error0;
2486                 bp = rbp;
2487                 nptr = 1;
2488         } else {
2489                 /* Our block is right, pick up the left block. */
2490                 rbp = bp;
2491                 xfs_btree_buf_to_ptr(cur, rbp, &rptr);
2492                 right = block;
2493                 xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2494                 error = xfs_btree_read_buf_block(cur, &lptr,
2495                                         cur->bc_nlevels - 1, 0, &left, &lbp);
2496                 if (error)
2497                         goto error0;
2498                 bp = lbp;
2499                 nptr = 2;
2500         }
2501         /* Fill in the new block's btree header and log it. */
2502         xfs_btree_init_block(cur, cur->bc_nlevels, 2, new);
2503         xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
2504         ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
2505                         !xfs_btree_ptr_is_null(cur, &rptr));
2506
2507         /* Fill in the key data in the new root. */
2508         if (xfs_btree_get_level(left) > 0) {
2509                 xfs_btree_copy_keys(cur,
2510                                 xfs_btree_key_addr(cur, 1, new),
2511                                 xfs_btree_key_addr(cur, 1, left), 1);
2512                 xfs_btree_copy_keys(cur,
2513                                 xfs_btree_key_addr(cur, 2, new),
2514                                 xfs_btree_key_addr(cur, 1, right), 1);
2515         } else {
2516                 cur->bc_ops->init_key_from_rec(
2517                                 xfs_btree_key_addr(cur, 1, new),
2518                                 xfs_btree_rec_addr(cur, 1, left));
2519                 cur->bc_ops->init_key_from_rec(
2520                                 xfs_btree_key_addr(cur, 2, new),
2521                                 xfs_btree_rec_addr(cur, 1, right));
2522         }
2523         xfs_btree_log_keys(cur, nbp, 1, 2);
2524
2525         /* Fill in the pointer data in the new root. */
2526         xfs_btree_copy_ptrs(cur,
2527                 xfs_btree_ptr_addr(cur, 1, new), &lptr, 1);
2528         xfs_btree_copy_ptrs(cur,
2529                 xfs_btree_ptr_addr(cur, 2, new), &rptr, 1);
2530         xfs_btree_log_ptrs(cur, nbp, 1, 2);
2531
2532         /* Fix up the cursor. */
2533         xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
2534         cur->bc_ptrs[cur->bc_nlevels] = nptr;
2535         cur->bc_nlevels++;
2536         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2537         *stat = 1;
2538         return 0;
2539 error0:
2540         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2541         return error;
2542 out0:
2543         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2544         *stat = 0;
2545         return 0;
2546 }
2547
2548 STATIC int
2549 xfs_btree_make_block_unfull(
2550         struct xfs_btree_cur    *cur,   /* btree cursor */
2551         int                     level,  /* btree level */
2552         int                     numrecs,/* # of recs in block */
2553         int                     *oindex,/* old tree index */
2554         int                     *index, /* new tree index */
2555         union xfs_btree_ptr     *nptr,  /* new btree ptr */
2556         struct xfs_btree_cur    **ncur, /* new btree cursor */
2557         union xfs_btree_rec     *nrec,  /* new record */
2558         int                     *stat)
2559 {
2560         union xfs_btree_key     key;    /* new btree key value */
2561         int                     error = 0;
2562
2563         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2564             level == cur->bc_nlevels - 1) {
2565                 struct xfs_inode *ip = cur->bc_private.b.ip;
2566
2567                 if (numrecs < cur->bc_ops->get_dmaxrecs(cur, level)) {
2568                         /* A root block that can be made bigger. */
2569
2570                         xfs_iroot_realloc(ip, 1, cur->bc_private.b.whichfork);
2571                 } else {
2572                         /* A root block that needs replacing */
2573                         int     logflags = 0;
2574
2575                         error = xfs_btree_new_iroot(cur, &logflags, stat);
2576                         if (error || *stat == 0)
2577                                 return error;
2578
2579                         xfs_trans_log_inode(cur->bc_tp, ip, logflags);
2580                 }
2581
2582                 return 0;
2583         }
2584
2585         /* First, try shifting an entry to the right neighbor. */
2586         error = xfs_btree_rshift(cur, level, stat);
2587         if (error || *stat)
2588                 return error;
2589
2590         /* Next, try shifting an entry to the left neighbor. */
2591         error = xfs_btree_lshift(cur, level, stat);
2592         if (error)
2593                 return error;
2594
2595         if (*stat) {
2596                 *oindex = *index = cur->bc_ptrs[level];
2597                 return 0;
2598         }
2599
2600         /*
2601          * Next, try splitting the current block in half.
2602          *
2603          * If this works we have to re-set our variables because we
2604          * could be in a different block now.
2605          */
2606         error = xfs_btree_split(cur, level, nptr, &key, ncur, stat);
2607         if (error || *stat == 0)
2608                 return error;
2609
2610
2611         *index = cur->bc_ptrs[level];
2612         cur->bc_ops->init_rec_from_key(&key, nrec);
2613         return 0;
2614 }
2615
2616 /*
2617  * Insert one record/level.  Return information to the caller
2618  * allowing the next level up to proceed if necessary.
2619  */
2620 STATIC int
2621 xfs_btree_insrec(
2622         struct xfs_btree_cur    *cur,   /* btree cursor */
2623         int                     level,  /* level to insert record at */
2624         union xfs_btree_ptr     *ptrp,  /* i/o: block number inserted */
2625         union xfs_btree_rec     *recp,  /* i/o: record data inserted */
2626         struct xfs_btree_cur    **curp, /* output: new cursor replacing cur */
2627         int                     *stat)  /* success/failure */
2628 {
2629         struct xfs_btree_block  *block; /* btree block */
2630         struct xfs_buf          *bp;    /* buffer for block */
2631         union xfs_btree_key     key;    /* btree key */
2632         union xfs_btree_ptr     nptr;   /* new block ptr */
2633         struct xfs_btree_cur    *ncur;  /* new btree cursor */
2634         union xfs_btree_rec     nrec;   /* new record count */
2635         int                     optr;   /* old key/record index */
2636         int                     ptr;    /* key/record index */
2637         int                     numrecs;/* number of records */
2638         int                     error;  /* error return value */
2639 #ifdef DEBUG
2640         int                     i;
2641 #endif
2642
2643         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2644         XFS_BTREE_TRACE_ARGIPR(cur, level, *ptrp, recp);
2645
2646         ncur = NULL;
2647
2648         /*
2649          * If we have an external root pointer, and we've made it to the
2650          * root level, allocate a new root block and we're done.
2651          */
2652         if (!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2653             (level >= cur->bc_nlevels)) {
2654                 error = xfs_btree_new_root(cur, stat);
2655                 xfs_btree_set_ptr_null(cur, ptrp);
2656
2657                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2658                 return error;
2659         }
2660
2661         /* If we're off the left edge, return failure. */
2662         ptr = cur->bc_ptrs[level];
2663         if (ptr == 0) {
2664                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2665                 *stat = 0;
2666                 return 0;
2667         }
2668
2669         /* Make a key out of the record data to be inserted, and save it. */
2670         cur->bc_ops->init_key_from_rec(&key, recp);
2671
2672         optr = ptr;
2673
2674         XFS_BTREE_STATS_INC(cur, insrec);
2675
2676         /* Get pointers to the btree buffer and block. */
2677         block = xfs_btree_get_block(cur, level, &bp);
2678         numrecs = xfs_btree_get_numrecs(block);
2679
2680 #ifdef DEBUG
2681         error = xfs_btree_check_block(cur, block, level, bp);
2682         if (error)
2683                 goto error0;
2684
2685         /* Check that the new entry is being inserted in the right place. */
2686         if (ptr <= numrecs) {
2687                 if (level == 0) {
2688                         ASSERT(cur->bc_ops->recs_inorder(cur, recp,
2689                                 xfs_btree_rec_addr(cur, ptr, block)));
2690                 } else {
2691                         ASSERT(cur->bc_ops->keys_inorder(cur, &key,
2692                                 xfs_btree_key_addr(cur, ptr, block)));
2693                 }
2694         }
2695 #endif
2696
2697         /*
2698          * If the block is full, we can't insert the new entry until we
2699          * make the block un-full.
2700          */
2701         xfs_btree_set_ptr_null(cur, &nptr);
2702         if (numrecs == cur->bc_ops->get_maxrecs(cur, level)) {
2703                 error = xfs_btree_make_block_unfull(cur, level, numrecs,
2704                                         &optr, &ptr, &nptr, &ncur, &nrec, stat);
2705                 if (error || *stat == 0)
2706                         goto error0;
2707         }
2708
2709         /*
2710          * The current block may have changed if the block was
2711          * previously full and we have just made space in it.
2712          */
2713         block = xfs_btree_get_block(cur, level, &bp);
2714         numrecs = xfs_btree_get_numrecs(block);
2715
2716 #ifdef DEBUG
2717         error = xfs_btree_check_block(cur, block, level, bp);
2718         if (error)
2719                 return error;
2720 #endif
2721
2722         /*
2723          * At this point we know there's room for our new entry in the block
2724          * we're pointing at.
2725          */
2726         XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr + 1);
2727
2728         if (level > 0) {
2729                 /* It's a nonleaf. make a hole in the keys and ptrs */
2730                 union xfs_btree_key     *kp;
2731                 union xfs_btree_ptr     *pp;
2732
2733                 kp = xfs_btree_key_addr(cur, ptr, block);
2734                 pp = xfs_btree_ptr_addr(cur, ptr, block);
2735
2736 #ifdef DEBUG
2737                 for (i = numrecs - ptr; i >= 0; i--) {
2738                         error = xfs_btree_check_ptr(cur, pp, i, level);
2739                         if (error)
2740                                 return error;
2741                 }
2742 #endif
2743
2744                 xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1);
2745                 xfs_btree_shift_ptrs(cur, pp, 1, numrecs - ptr + 1);
2746
2747 #ifdef DEBUG
2748                 error = xfs_btree_check_ptr(cur, ptrp, 0, level);
2749                 if (error)
2750                         goto error0;
2751 #endif
2752
2753                 /* Now put the new data in, bump numrecs and log it. */
2754                 xfs_btree_copy_keys(cur, kp, &key, 1);
2755                 xfs_btree_copy_ptrs(cur, pp, ptrp, 1);
2756                 numrecs++;
2757                 xfs_btree_set_numrecs(block, numrecs);
2758                 xfs_btree_log_ptrs(cur, bp, ptr, numrecs);
2759                 xfs_btree_log_keys(cur, bp, ptr, numrecs);
2760 #ifdef DEBUG
2761                 if (ptr < numrecs) {
2762                         ASSERT(cur->bc_ops->keys_inorder(cur, kp,
2763                                 xfs_btree_key_addr(cur, ptr + 1, block)));
2764                 }
2765 #endif
2766         } else {
2767                 /* It's a leaf. make a hole in the records */
2768                 union xfs_btree_rec             *rp;
2769
2770                 rp = xfs_btree_rec_addr(cur, ptr, block);
2771
2772                 xfs_btree_shift_recs(cur, rp, 1, numrecs - ptr + 1);
2773
2774                 /* Now put the new data in, bump numrecs and log it. */
2775                 xfs_btree_copy_recs(cur, rp, recp, 1);
2776                 xfs_btree_set_numrecs(block, ++numrecs);
2777                 xfs_btree_log_recs(cur, bp, ptr, numrecs);
2778 #ifdef DEBUG
2779                 if (ptr < numrecs) {
2780                         ASSERT(cur->bc_ops->recs_inorder(cur, rp,
2781                                 xfs_btree_rec_addr(cur, ptr + 1, block)));
2782                 }
2783 #endif
2784         }
2785
2786         /* Log the new number of records in the btree header. */
2787         xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
2788
2789         /* If we inserted at the start of a block, update the parents' keys. */
2790         if (optr == 1) {
2791                 error = xfs_btree_updkey(cur, &key, level + 1);
2792                 if (error)
2793                         goto error0;
2794         }
2795
2796         /*
2797          * If we are tracking the last record in the tree and
2798          * we are at the far right edge of the tree, update it.
2799          */
2800         if (xfs_btree_is_lastrec(cur, block, level)) {
2801                 cur->bc_ops->update_lastrec(cur, block, recp,
2802                                             ptr, LASTREC_INSREC);
2803         }
2804
2805         /*
2806          * Return the new block number, if any.
2807          * If there is one, give back a record value and a cursor too.
2808          */
2809         *ptrp = nptr;
2810         if (!xfs_btree_ptr_is_null(cur, &nptr)) {
2811                 *recp = nrec;
2812                 *curp = ncur;
2813         }
2814
2815         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2816         *stat = 1;
2817         return 0;
2818
2819 error0:
2820         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2821         return error;
2822 }
2823
2824 /*
2825  * Insert the record at the point referenced by cur.
2826  *
2827  * A multi-level split of the tree on insert will invalidate the original
2828  * cursor.  All callers of this function should assume that the cursor is
2829  * no longer valid and revalidate it.
2830  */
2831 int
2832 xfs_btree_insert(
2833         struct xfs_btree_cur    *cur,
2834         int                     *stat)
2835 {
2836         int                     error;  /* error return value */
2837         int                     i;      /* result value, 0 for failure */
2838         int                     level;  /* current level number in btree */
2839         union xfs_btree_ptr     nptr;   /* new block number (split result) */
2840         struct xfs_btree_cur    *ncur;  /* new cursor (split result) */
2841         struct xfs_btree_cur    *pcur;  /* previous level's cursor */
2842         union xfs_btree_rec     rec;    /* record to insert */
2843
2844         level = 0;
2845         ncur = NULL;
2846         pcur = cur;
2847
2848         xfs_btree_set_ptr_null(cur, &nptr);
2849         cur->bc_ops->init_rec_from_cur(cur, &rec);
2850
2851         /*
2852          * Loop going up the tree, starting at the leaf level.
2853          * Stop when we don't get a split block, that must mean that
2854          * the insert is finished with this level.
2855          */
2856         do {
2857                 /*
2858                  * Insert nrec/nptr into this level of the tree.
2859                  * Note if we fail, nptr will be null.
2860                  */
2861                 error = xfs_btree_insrec(pcur, level, &nptr, &rec, &ncur, &i);
2862                 if (error) {
2863                         if (pcur != cur)
2864                                 xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
2865                         goto error0;
2866                 }
2867
2868                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
2869                 level++;
2870
2871                 /*
2872                  * See if the cursor we just used is trash.
2873                  * Can't trash the caller's cursor, but otherwise we should
2874                  * if ncur is a new cursor or we're about to be done.
2875                  */
2876                 if (pcur != cur &&
2877                     (ncur || xfs_btree_ptr_is_null(cur, &nptr))) {
2878                         /* Save the state from the cursor before we trash it */
2879                         if (cur->bc_ops->update_cursor)
2880                                 cur->bc_ops->update_cursor(pcur, cur);
2881                         cur->bc_nlevels = pcur->bc_nlevels;
2882                         xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
2883                 }
2884                 /* If we got a new cursor, switch to it. */
2885                 if (ncur) {
2886                         pcur = ncur;
2887                         ncur = NULL;
2888                 }
2889         } while (!xfs_btree_ptr_is_null(cur, &nptr));
2890
2891         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2892         *stat = i;
2893         return 0;
2894 error0:
2895         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2896         return error;
2897 }
2898
2899 /*
2900  * Try to merge a non-leaf block back into the inode root.
2901  *
2902  * Note: the killroot names comes from the fact that we're effectively
2903  * killing the old root block.  But because we can't just delete the
2904  * inode we have to copy the single block it was pointing to into the
2905  * inode.
2906  */
2907 STATIC int
2908 xfs_btree_kill_iroot(
2909         struct xfs_btree_cur    *cur)
2910 {
2911         int                     whichfork = cur->bc_private.b.whichfork;
2912         struct xfs_inode        *ip = cur->bc_private.b.ip;
2913         struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, whichfork);
2914         struct xfs_btree_block  *block;
2915         struct xfs_btree_block  *cblock;
2916         union xfs_btree_key     *kp;
2917         union xfs_btree_key     *ckp;
2918         union xfs_btree_ptr     *pp;
2919         union xfs_btree_ptr     *cpp;
2920         struct xfs_buf          *cbp;
2921         int                     level;
2922         int                     index;
2923         int                     numrecs;
2924 #ifdef DEBUG
2925         union xfs_btree_ptr     ptr;
2926         int                     i;
2927 #endif
2928
2929         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2930
2931         ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
2932         ASSERT(cur->bc_nlevels > 1);
2933
2934         /*
2935          * Don't deal with the root block needs to be a leaf case.
2936          * We're just going to turn the thing back into extents anyway.
2937          */
2938         level = cur->bc_nlevels - 1;
2939         if (level == 1)
2940                 goto out0;
2941
2942         /*
2943          * Give up if the root has multiple children.
2944          */
2945         block = xfs_btree_get_iroot(cur);
2946         if (xfs_btree_get_numrecs(block) != 1)
2947                 goto out0;
2948
2949         cblock = xfs_btree_get_block(cur, level - 1, &cbp);
2950         numrecs = xfs_btree_get_numrecs(cblock);
2951
2952         /*
2953          * Only do this if the next level will fit.
2954          * Then the data must be copied up to the inode,
2955          * instead of freeing the root you free the next level.
2956          */
2957         if (numrecs > cur->bc_ops->get_dmaxrecs(cur, level))
2958                 goto out0;
2959
2960         XFS_BTREE_STATS_INC(cur, killroot);
2961
2962 #ifdef DEBUG
2963         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
2964         ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
2965         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
2966         ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
2967 #endif
2968
2969         index = numrecs - cur->bc_ops->get_maxrecs(cur, level);
2970         if (index) {
2971                 xfs_iroot_realloc(cur->bc_private.b.ip, index,
2972                                   cur->bc_private.b.whichfork);
2973                 block = ifp->if_broot;
2974         }
2975
2976         be16_add_cpu(&block->bb_numrecs, index);
2977         ASSERT(block->bb_numrecs == cblock->bb_numrecs);
2978
2979         kp = xfs_btree_key_addr(cur, 1, block);
2980         ckp = xfs_btree_key_addr(cur, 1, cblock);
2981         xfs_btree_copy_keys(cur, kp, ckp, numrecs);
2982
2983         pp = xfs_btree_ptr_addr(cur, 1, block);
2984         cpp = xfs_btree_ptr_addr(cur, 1, cblock);
2985 #ifdef DEBUG
2986         for (i = 0; i < numrecs; i++) {
2987                 int             error;
2988
2989                 error = xfs_btree_check_ptr(cur, cpp, i, level - 1);
2990                 if (error) {
2991                         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2992                         return error;
2993                 }
2994         }
2995 #endif
2996         xfs_btree_copy_ptrs(cur, pp, cpp, numrecs);
2997
2998         cur->bc_ops->free_block(cur, cbp);
2999         XFS_BTREE_STATS_INC(cur, free);
3000
3001         cur->bc_bufs[level - 1] = NULL;
3002         be16_add_cpu(&block->bb_level, -1);
3003         xfs_trans_log_inode(cur->bc_tp, ip,
3004                 XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_private.b.whichfork));
3005         cur->bc_nlevels--;
3006 out0:
3007         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3008         return 0;
3009 }
3010
3011 /*
3012  * Kill the current root node, and replace it with it's only child node.
3013  */
3014 STATIC int
3015 xfs_btree_kill_root(
3016         struct xfs_btree_cur    *cur,
3017         struct xfs_buf          *bp,
3018         int                     level,
3019         union xfs_btree_ptr     *newroot)
3020 {
3021         int                     error;
3022
3023         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
3024         XFS_BTREE_STATS_INC(cur, killroot);
3025
3026         /*
3027          * Update the root pointer, decreasing the level by 1 and then
3028          * free the old root.
3029          */
3030         cur->bc_ops->set_root(cur, newroot, -1);
3031
3032         error = cur->bc_ops->free_block(cur, bp);
3033         if (error) {
3034                 XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
3035                 return error;
3036         }
3037
3038         XFS_BTREE_STATS_INC(cur, free);
3039
3040         cur->bc_bufs[level] = NULL;
3041         cur->bc_ra[level] = 0;
3042         cur->bc_nlevels--;
3043
3044         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3045         return 0;
3046 }
3047
3048 STATIC int
3049 xfs_btree_dec_cursor(
3050         struct xfs_btree_cur    *cur,
3051         int                     level,
3052         int                     *stat)
3053 {
3054         int                     error;
3055         int                     i;
3056
3057         if (level > 0) {
3058                 error = xfs_btree_decrement(cur, level, &i);
3059                 if (error)
3060                         return error;
3061         }
3062
3063         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3064         *stat = 1;
3065         return 0;
3066 }
3067
3068 /*
3069  * Single level of the btree record deletion routine.
3070  * Delete record pointed to by cur/level.
3071  * Remove the record from its block then rebalance the tree.
3072  * Return 0 for error, 1 for done, 2 to go on to the next level.
3073  */
3074 STATIC int                                      /* error */
3075 xfs_btree_delrec(
3076         struct xfs_btree_cur    *cur,           /* btree cursor */
3077         int                     level,          /* level removing record from */
3078         int                     *stat)          /* fail/done/go-on */
3079 {
3080         struct xfs_btree_block  *block;         /* btree block */
3081         union xfs_btree_ptr     cptr;           /* current block ptr */
3082         struct xfs_buf          *bp;            /* buffer for block */
3083         int                     error;          /* error return value */
3084         int                     i;              /* loop counter */
3085         union xfs_btree_key     key;            /* storage for keyp */
3086         union xfs_btree_key     *keyp = &key;   /* passed to the next level */
3087         union xfs_btree_ptr     lptr;           /* left sibling block ptr */
3088         struct xfs_buf          *lbp;           /* left buffer pointer */
3089         struct xfs_btree_block  *left;          /* left btree block */
3090         int                     lrecs = 0;      /* left record count */
3091         int                     ptr;            /* key/record index */
3092         union xfs_btree_ptr     rptr;           /* right sibling block ptr */
3093         struct xfs_buf          *rbp;           /* right buffer pointer */
3094         struct xfs_btree_block  *right;         /* right btree block */
3095         struct xfs_btree_block  *rrblock;       /* right-right btree block */
3096         struct xfs_buf          *rrbp;          /* right-right buffer pointer */
3097         int                     rrecs = 0;      /* right record count */
3098         struct xfs_btree_cur    *tcur;          /* temporary btree cursor */
3099         int                     numrecs;        /* temporary numrec count */
3100
3101         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
3102         XFS_BTREE_TRACE_ARGI(cur, level);
3103
3104         tcur = NULL;
3105
3106         /* Get the index of the entry being deleted, check for nothing there. */
3107         ptr = cur->bc_ptrs[level];
3108         if (ptr == 0) {
3109                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3110                 *stat = 0;
3111                 return 0;
3112         }
3113
3114         /* Get the buffer & block containing the record or key/ptr. */
3115         block = xfs_btree_get_block(cur, level, &bp);
3116         numrecs = xfs_btree_get_numrecs(block);
3117
3118 #ifdef DEBUG
3119         error = xfs_btree_check_block(cur, block, level, bp);
3120         if (error)
3121                 goto error0;
3122 #endif
3123
3124         /* Fail if we're off the end of the block. */
3125         if (ptr > numrecs) {
3126                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3127                 *stat = 0;
3128                 return 0;
3129         }
3130
3131         XFS_BTREE_STATS_INC(cur, delrec);
3132         XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr);
3133
3134         /* Excise the entries being deleted. */
3135         if (level > 0) {
3136                 /* It's a nonleaf. operate on keys and ptrs */
3137                 union xfs_btree_key     *lkp;
3138                 union xfs_btree_ptr     *lpp;
3139
3140                 lkp = xfs_btree_key_addr(cur, ptr + 1, block);
3141                 lpp = xfs_btree_ptr_addr(cur, ptr + 1, block);
3142
3143 #ifdef DEBUG
3144                 for (i = 0; i < numrecs - ptr; i++) {
3145                         error = xfs_btree_check_ptr(cur, lpp, i, level);
3146                         if (error)
3147                                 goto error0;
3148                 }
3149 #endif
3150
3151                 if (ptr < numrecs) {
3152                         xfs_btree_shift_keys(cur, lkp, -1, numrecs - ptr);
3153                         xfs_btree_shift_ptrs(cur, lpp, -1, numrecs - ptr);
3154                         xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
3155                         xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
3156                 }
3157
3158                 /*
3159                  * If it's the first record in the block, we'll need to pass a
3160                  * key up to the next level (updkey).
3161                  */
3162                 if (ptr == 1)
3163                         keyp = xfs_btree_key_addr(cur, 1, block);
3164         } else {
3165                 /* It's a leaf. operate on records */
3166                 if (ptr < numrecs) {
3167                         xfs_btree_shift_recs(cur,
3168                                 xfs_btree_rec_addr(cur, ptr + 1, block),
3169                                 -1, numrecs - ptr);
3170                         xfs_btree_log_recs(cur, bp, ptr, numrecs - 1);
3171                 }
3172
3173                 /*
3174                  * If it's the first record in the block, we'll need a key
3175                  * structure to pass up to the next level (updkey).
3176                  */
3177                 if (ptr == 1) {
3178                         cur->bc_ops->init_key_from_rec(&key,
3179                                         xfs_btree_rec_addr(cur, 1, block));
3180                         keyp = &key;
3181                 }
3182         }
3183
3184         /*
3185          * Decrement and log the number of entries in the block.
3186          */
3187         xfs_btree_set_numrecs(block, --numrecs);
3188         xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3189
3190         /*
3191          * If we are tracking the last record in the tree and
3192          * we are at the far right edge of the tree, update it.
3193          */
3194         if (xfs_btree_is_lastrec(cur, block, level)) {
3195                 cur->bc_ops->update_lastrec(cur, block, NULL,
3196                                             ptr, LASTREC_DELREC);
3197         }
3198
3199         /*
3200          * We're at the root level.  First, shrink the root block in-memory.
3201          * Try to get rid of the next level down.  If we can't then there's
3202          * nothing left to do.
3203          */
3204         if (level == cur->bc_nlevels - 1) {
3205                 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3206                         xfs_iroot_realloc(cur->bc_private.b.ip, -1,
3207                                           cur->bc_private.b.whichfork);
3208
3209                         error = xfs_btree_kill_iroot(cur);
3210                         if (error)
3211                                 goto error0;
3212
3213                         error = xfs_btree_dec_cursor(cur, level, stat);
3214                         if (error)
3215                                 goto error0;
3216                         *stat = 1;
3217                         return 0;
3218                 }
3219
3220                 /*
3221                  * If this is the root level, and there's only one entry left,
3222                  * and it's NOT the leaf level, then we can get rid of this
3223                  * level.
3224                  */
3225                 if (numrecs == 1 && level > 0) {
3226                         union xfs_btree_ptr     *pp;
3227                         /*
3228                          * pp is still set to the first pointer in the block.
3229                          * Make it the new root of the btree.
3230                          */
3231                         pp = xfs_btree_ptr_addr(cur, 1, block);
3232                         error = xfs_btree_kill_root(cur, bp, level, pp);
3233                         if (error)
3234                                 goto error0;
3235                 } else if (level > 0) {
3236                         error = xfs_btree_dec_cursor(cur, level, stat);
3237                         if (error)
3238                                 goto error0;
3239                 }
3240                 *stat = 1;
3241                 return 0;
3242         }
3243
3244         /*
3245          * If we deleted the leftmost entry in the block, update the
3246          * key values above us in the tree.
3247          */
3248         if (ptr == 1) {
3249                 error = xfs_btree_updkey(cur, keyp, level + 1);
3250                 if (error)
3251                         goto error0;
3252         }
3253
3254         /*
3255          * If the number of records remaining in the block is at least
3256          * the minimum, we're done.
3257          */
3258         if (numrecs >= cur->bc_ops->get_minrecs(cur, level)) {
3259                 error = xfs_btree_dec_cursor(cur, level, stat);
3260                 if (error)
3261                         goto error0;
3262                 return 0;
3263         }
3264
3265         /*
3266          * Otherwise, we have to move some records around to keep the
3267          * tree balanced.  Look at the left and right sibling blocks to
3268          * see if we can re-balance by moving only one record.
3269          */
3270         xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3271         xfs_btree_get_sibling(cur, block, &lptr, XFS_BB_LEFTSIB);
3272
3273         if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3274                 /*
3275                  * One child of root, need to get a chance to copy its contents
3276                  * into the root and delete it. Can't go up to next level,
3277                  * there's nothing to delete there.
3278                  */
3279                 if (xfs_btree_ptr_is_null(cur, &rptr) &&
3280                     xfs_btree_ptr_is_null(cur, &lptr) &&
3281                     level == cur->bc_nlevels - 2) {
3282                         error = xfs_btree_kill_iroot(cur);
3283                         if (!error)
3284                                 error = xfs_btree_dec_cursor(cur, level, stat);
3285                         if (error)
3286                                 goto error0;
3287                         return 0;
3288                 }
3289         }
3290
3291         ASSERT(!xfs_btree_ptr_is_null(cur, &rptr) ||
3292                !xfs_btree_ptr_is_null(cur, &lptr));
3293
3294         /*
3295          * Duplicate the cursor so our btree manipulations here won't
3296          * disrupt the next level up.
3297          */
3298         error = xfs_btree_dup_cursor(cur, &tcur);
3299         if (error)
3300                 goto error0;
3301
3302         /*
3303          * If there's a right sibling, see if it's ok to shift an entry
3304          * out of it.
3305          */
3306         if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3307                 /*
3308                  * Move the temp cursor to the last entry in the next block.
3309                  * Actually any entry but the first would suffice.
3310                  */
3311                 i = xfs_btree_lastrec(tcur, level);
3312                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3313
3314                 error = xfs_btree_increment(tcur, level, &i);
3315                 if (error)
3316                         goto error0;
3317                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3318
3319                 i = xfs_btree_lastrec(tcur, level);
3320                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3321
3322                 /* Grab a pointer to the block. */
3323                 right = xfs_btree_get_block(tcur, level, &rbp);
3324 #ifdef DEBUG
3325                 error = xfs_btree_check_block(tcur, right, level, rbp);
3326                 if (error)
3327                         goto error0;
3328 #endif
3329                 /* Grab the current block number, for future use. */
3330                 xfs_btree_get_sibling(tcur, right, &cptr, XFS_BB_LEFTSIB);
3331
3332                 /*
3333                  * If right block is full enough so that removing one entry
3334                  * won't make it too empty, and left-shifting an entry out
3335                  * of right to us works, we're done.
3336                  */
3337                 if (xfs_btree_get_numrecs(right) - 1 >=
3338                     cur->bc_ops->get_minrecs(tcur, level)) {
3339                         error = xfs_btree_lshift(tcur, level, &i);
3340                         if (error)
3341                                 goto error0;
3342                         if (i) {
3343                                 ASSERT(xfs_btree_get_numrecs(block) >=
3344                                        cur->bc_ops->get_minrecs(tcur, level));
3345
3346                                 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3347                                 tcur = NULL;
3348
3349                                 error = xfs_btree_dec_cursor(cur, level, stat);
3350                                 if (error)
3351                                         goto error0;
3352                                 return 0;
3353                         }
3354                 }
3355
3356                 /*
3357                  * Otherwise, grab the number of records in right for
3358                  * future reference, and fix up the temp cursor to point
3359                  * to our block again (last record).
3360                  */
3361                 rrecs = xfs_btree_get_numrecs(right);
3362                 if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3363                         i = xfs_btree_firstrec(tcur, level);
3364                         XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3365
3366                         error = xfs_btree_decrement(tcur, level, &i);
3367                         if (error)
3368                                 goto error0;
3369                         XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3370                 }
3371         }
3372
3373         /*
3374          * If there's a left sibling, see if it's ok to shift an entry
3375          * out of it.
3376          */
3377         if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3378                 /*
3379                  * Move the temp cursor to the first entry in the
3380                  * previous block.
3381                  */
3382                 i = xfs_btree_firstrec(tcur, level);
3383                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3384
3385                 error = xfs_btree_decrement(tcur, level, &i);
3386                 if (error)
3387                         goto error0;
3388                 i = xfs_btree_firstrec(tcur, level);
3389                 XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3390
3391                 /* Grab a pointer to the block. */
3392                 left = xfs_btree_get_block(tcur, level, &lbp);
3393 #ifdef DEBUG
3394                 error = xfs_btree_check_block(cur, left, level, lbp);
3395                 if (error)
3396                         goto error0;
3397 #endif
3398                 /* Grab the current block number, for future use. */
3399                 xfs_btree_get_sibling(tcur, left, &cptr, XFS_BB_RIGHTSIB);
3400
3401                 /*
3402                  * If left block is full enough so that removing one entry
3403                  * won't make it too empty, and right-shifting an entry out
3404                  * of left to us works, we're done.
3405                  */
3406                 if (xfs_btree_get_numrecs(left) - 1 >=
3407                     cur->bc_ops->get_minrecs(tcur, level)) {
3408                         error = xfs_btree_rshift(tcur, level, &i);
3409                         if (error)
3410                                 goto error0;
3411                         if (i) {
3412                                 ASSERT(xfs_btree_get_numrecs(block) >=
3413                                        cur->bc_ops->get_minrecs(tcur, level));
3414                                 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3415                                 tcur = NULL;
3416                                 if (level == 0)
3417                                         cur->bc_ptrs[0]++;
3418                                 XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3419                                 *stat = 1;
3420                                 return 0;
3421                         }
3422                 }
3423
3424                 /*
3425                  * Otherwise, grab the number of records in right for
3426                  * future reference.
3427                  */
3428                 lrecs = xfs_btree_get_numrecs(left);
3429         }
3430
3431         /* Delete the temp cursor, we're done with it. */
3432         xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3433         tcur = NULL;
3434
3435         /* If here, we need to do a join to keep the tree balanced. */
3436         ASSERT(!xfs_btree_ptr_is_null(cur, &cptr));
3437
3438         if (!xfs_btree_ptr_is_null(cur, &lptr) &&
3439             lrecs + xfs_btree_get_numrecs(block) <=
3440                         cur->bc_ops->get_maxrecs(cur, level)) {
3441                 /*
3442                  * Set "right" to be the starting block,
3443                  * "left" to be the left neighbor.
3444                  */
3445                 rptr = cptr;
3446                 right = block;
3447                 rbp = bp;
3448                 error = xfs_btree_read_buf_block(cur, &lptr, level,
3449                                                         0, &left, &lbp);
3450                 if (error)
3451                         goto error0;
3452
3453         /*
3454          * If that won't work, see if we can join with the right neighbor block.
3455          */
3456         } else if (!xfs_btree_ptr_is_null(cur, &rptr) &&
3457                    rrecs + xfs_btree_get_numrecs(block) <=
3458                         cur->bc_ops->get_maxrecs(cur, level)) {
3459                 /*
3460                  * Set "left" to be the starting block,
3461                  * "right" to be the right neighbor.
3462                  */
3463                 lptr = cptr;
3464                 left = block;
3465                 lbp = bp;
3466                 error = xfs_btree_read_buf_block(cur, &rptr, level,
3467                                                         0, &right, &rbp);
3468                 if (error)
3469                         goto error0;
3470
3471         /*
3472          * Otherwise, we can't fix the imbalance.
3473          * Just return.  This is probably a logic error, but it's not fatal.
3474          */
3475         } else {
3476                 error = xfs_btree_dec_cursor(cur, level, stat);
3477                 if (error)
3478                         goto error0;
3479                 return 0;
3480         }
3481
3482         rrecs = xfs_btree_get_numrecs(right);
3483         lrecs = xfs_btree_get_numrecs(left);
3484
3485         /*
3486          * We're now going to join "left" and "right" by moving all the stuff
3487          * in "right" to "left" and deleting "right".
3488          */
3489         XFS_BTREE_STATS_ADD(cur, moves, rrecs);
3490         if (level > 0) {
3491                 /* It's a non-leaf.  Move keys and pointers. */
3492                 union xfs_btree_key     *lkp;   /* left btree key */
3493                 union xfs_btree_ptr     *lpp;   /* left address pointer */
3494                 union xfs_btree_key     *rkp;   /* right btree key */
3495                 union xfs_btree_ptr     *rpp;   /* right address pointer */
3496
3497                 lkp = xfs_btree_key_addr(cur, lrecs + 1, left);
3498                 lpp = xfs_btree_ptr_addr(cur, lrecs + 1, left);
3499                 rkp = xfs_btree_key_addr(cur, 1, right);
3500                 rpp = xfs_btree_ptr_addr(cur, 1, right);
3501 #ifdef DEBUG
3502                 for (i = 1; i < rrecs; i++) {
3503                         error = xfs_btree_check_ptr(cur, rpp, i, level);
3504                         if (error)
3505                                 goto error0;
3506                 }
3507 #endif
3508                 xfs_btree_copy_keys(cur, lkp, rkp, rrecs);
3509                 xfs_btree_copy_ptrs(cur, lpp, rpp, rrecs);
3510
3511                 xfs_btree_log_keys(cur, lbp, lrecs + 1, lrecs + rrecs);
3512                 xfs_btree_log_ptrs(cur, lbp, lrecs + 1, lrecs + rrecs);
3513         } else {
3514                 /* It's a leaf.  Move records.  */
3515                 union xfs_btree_rec     *lrp;   /* left record pointer */
3516                 union xfs_btree_rec     *rrp;   /* right record pointer */
3517
3518                 lrp = xfs_btree_rec_addr(cur, lrecs + 1, left);
3519                 rrp = xfs_btree_rec_addr(cur, 1, right);
3520
3521                 xfs_btree_copy_recs(cur, lrp, rrp, rrecs);
3522                 xfs_btree_log_recs(cur, lbp, lrecs + 1, lrecs + rrecs);
3523         }
3524
3525         XFS_BTREE_STATS_INC(cur, join);
3526
3527         /*
3528          * Fix up the number of records and right block pointer in the
3529          * surviving block, and log it.
3530          */
3531         xfs_btree_set_numrecs(left, lrecs + rrecs);
3532         xfs_btree_get_sibling(cur, right, &cptr, XFS_BB_RIGHTSIB),
3533         xfs_btree_set_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
3534         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
3535
3536         /* If there is a right sibling, point it to the remaining block. */
3537         xfs_btree_get_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
3538         if (!xfs_btree_ptr_is_null(cur, &cptr)) {
3539                 error = xfs_btree_read_buf_block(cur, &cptr, level,
3540                                                         0, &rrblock, &rrbp);
3541                 if (error)
3542                         goto error0;
3543                 xfs_btree_set_sibling(cur, rrblock, &lptr, XFS_BB_LEFTSIB);
3544                 xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
3545         }
3546
3547         /* Free the deleted block. */
3548         error = cur->bc_ops->free_block(cur, rbp);
3549         if (error)
3550                 goto error0;
3551         XFS_BTREE_STATS_INC(cur, free);
3552
3553         /*
3554          * If we joined with the left neighbor, set the buffer in the
3555          * cursor to the left block, and fix up the index.
3556          */
3557         if (bp != lbp) {
3558                 cur->bc_bufs[level] = lbp;
3559                 cur->bc_ptrs[level] += lrecs;
3560                 cur->bc_ra[level] = 0;
3561         }
3562         /*
3563          * If we joined with the right neighbor and there's a level above
3564          * us, increment the cursor at that level.
3565          */
3566         else if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) ||
3567                    (level + 1 < cur->bc_nlevels)) {
3568                 error = xfs_btree_increment(cur, level + 1, &i);
3569                 if (error)
3570                         goto error0;
3571         }
3572
3573         /*
3574          * Readjust the ptr at this level if it's not a leaf, since it's
3575          * still pointing at the deletion point, which makes the cursor
3576          * inconsistent.  If this makes the ptr 0, the caller fixes it up.
3577          * We can't use decrement because it would change the next level up.
3578          */
3579         if (level > 0)
3580                 cur->bc_ptrs[level]--;
3581
3582         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3583         /* Return value means the next level up has something to do. */
3584         *stat = 2;
3585         return 0;
3586
3587 error0:
3588         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
3589         if (tcur)
3590                 xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
3591         return error;
3592 }
3593
3594 /*
3595  * Delete the record pointed to by cur.
3596  * The cursor refers to the place where the record was (could be inserted)
3597  * when the operation returns.
3598  */
3599 int                                     /* error */
3600 xfs_btree_delete(
3601         struct xfs_btree_cur    *cur,
3602         int                     *stat)  /* success/failure */
3603 {
3604         int                     error;  /* error return value */
3605         int                     level;
3606         int                     i;
3607
3608         XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
3609
3610         /*
3611          * Go up the tree, starting at leaf level.
3612          *
3613          * If 2 is returned then a join was done; go to the next level.
3614          * Otherwise we are done.
3615          */
3616         for (level = 0, i = 2; i == 2; level++) {
3617                 error = xfs_btree_delrec(cur, level, &i);
3618                 if (error)
3619                         goto error0;
3620         }
3621
3622         if (i == 0) {
3623                 for (level = 1; level < cur->bc_nlevels; level++) {
3624                         if (cur->bc_ptrs[level] == 0) {
3625                                 error = xfs_btree_decrement(cur, level, &i);
3626                                 if (error)
3627                                         goto error0;
3628                                 break;
3629                         }
3630                 }
3631         }
3632
3633         XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3634         *stat = i;
3635         return 0;
3636 error0:
3637         XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
3638         return error;
3639 }
3640
3641 /*
3642  * Get the data from the pointed-to record.
3643  */
3644 int                                     /* error */
3645 xfs_btree_get_rec(
3646         struct xfs_btree_cur    *cur,   /* btree cursor */
3647         union xfs_btree_rec     **recp, /* output: btree record */
3648         int                     *stat)  /* output: success/failure */
3649 {
3650         struct xfs_btree_block  *block; /* btree block */
3651         struct xfs_buf          *bp;    /* buffer pointer */
3652         int                     ptr;    /* record number */
3653 #ifdef DEBUG
3654         int                     error;  /* error return value */
3655 #endif
3656
3657         ptr = cur->bc_ptrs[0];
3658         block = xfs_btree_get_block(cur, 0, &bp);
3659
3660 #ifdef DEBUG
3661         error = xfs_btree_check_block(cur, block, 0, bp);
3662         if (error)
3663                 return error;
3664 #endif
3665
3666         /*
3667          * Off the right end or left end, return failure.
3668          */
3669         if (ptr > xfs_btree_get_numrecs(block) || ptr <= 0) {
3670                 *stat = 0;
3671                 return 0;
3672         }
3673
3674         /*
3675          * Point to the record and extract its data.
3676          */
3677         *recp = xfs_btree_rec_addr(cur, ptr, block);
3678         *stat = 1;
3679         return 0;
3680 }