linux/fs/xfs/xfs_btree.c
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   1/*
   2 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
   3 * All Rights Reserved.
   4 *
   5 * This program is free software; you can redistribute it and/or
   6 * modify it under the terms of the GNU General Public License as
   7 * published by the Free Software Foundation.
   8 *
   9 * This program is distributed in the hope that it would be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write the Free Software Foundation,
  16 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17 */
  18#include "xfs.h"
  19#include "xfs_fs.h"
  20#include "xfs_types.h"
  21#include "xfs_bit.h"
  22#include "xfs_log.h"
  23#include "xfs_trans.h"
  24#include "xfs_sb.h"
  25#include "xfs_ag.h"
  26#include "xfs_mount.h"
  27#include "xfs_bmap_btree.h"
  28#include "xfs_alloc_btree.h"
  29#include "xfs_ialloc_btree.h"
  30#include "xfs_dinode.h"
  31#include "xfs_inode.h"
  32#include "xfs_inode_item.h"
  33#include "xfs_btree.h"
  34#include "xfs_error.h"
  35#include "xfs_trace.h"
  36
  37/*
  38 * Cursor allocation zone.
  39 */
  40kmem_zone_t     *xfs_btree_cur_zone;
  41
  42/*
  43 * Btree magic numbers.
  44 */
  45const __uint32_t xfs_magics[XFS_BTNUM_MAX] = {
  46        XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, XFS_BMAP_MAGIC, XFS_IBT_MAGIC
  47};
  48
  49
  50STATIC int                              /* error (0 or EFSCORRUPTED) */
  51xfs_btree_check_lblock(
  52        struct xfs_btree_cur    *cur,   /* btree cursor */
  53        struct xfs_btree_block  *block, /* btree long form block pointer */
  54        int                     level,  /* level of the btree block */
  55        struct xfs_buf          *bp)    /* buffer for block, if any */
  56{
  57        int                     lblock_ok; /* block passes checks */
  58        struct xfs_mount        *mp;    /* file system mount point */
  59
  60        mp = cur->bc_mp;
  61        lblock_ok =
  62                be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
  63                be16_to_cpu(block->bb_level) == level &&
  64                be16_to_cpu(block->bb_numrecs) <=
  65                        cur->bc_ops->get_maxrecs(cur, level) &&
  66                block->bb_u.l.bb_leftsib &&
  67                (block->bb_u.l.bb_leftsib == cpu_to_be64(NULLDFSBNO) ||
  68                 XFS_FSB_SANITY_CHECK(mp,
  69                        be64_to_cpu(block->bb_u.l.bb_leftsib))) &&
  70                block->bb_u.l.bb_rightsib &&
  71                (block->bb_u.l.bb_rightsib == cpu_to_be64(NULLDFSBNO) ||
  72                 XFS_FSB_SANITY_CHECK(mp,
  73                        be64_to_cpu(block->bb_u.l.bb_rightsib)));
  74        if (unlikely(XFS_TEST_ERROR(!lblock_ok, mp,
  75                        XFS_ERRTAG_BTREE_CHECK_LBLOCK,
  76                        XFS_RANDOM_BTREE_CHECK_LBLOCK))) {
  77                if (bp)
  78                        trace_xfs_btree_corrupt(bp, _RET_IP_);
  79                XFS_ERROR_REPORT("xfs_btree_check_lblock", XFS_ERRLEVEL_LOW,
  80                                 mp);
  81                return XFS_ERROR(EFSCORRUPTED);
  82        }
  83        return 0;
  84}
  85
  86STATIC int                              /* error (0 or EFSCORRUPTED) */
  87xfs_btree_check_sblock(
  88        struct xfs_btree_cur    *cur,   /* btree cursor */
  89        struct xfs_btree_block  *block, /* btree short form block pointer */
  90        int                     level,  /* level of the btree block */
  91        struct xfs_buf          *bp)    /* buffer containing block */
  92{
  93        struct xfs_buf          *agbp;  /* buffer for ag. freespace struct */
  94        struct xfs_agf          *agf;   /* ag. freespace structure */
  95        xfs_agblock_t           agflen; /* native ag. freespace length */
  96        int                     sblock_ok; /* block passes checks */
  97
  98        agbp = cur->bc_private.a.agbp;
  99        agf = XFS_BUF_TO_AGF(agbp);
 100        agflen = be32_to_cpu(agf->agf_length);
 101        sblock_ok =
 102                be32_to_cpu(block->bb_magic) == xfs_magics[cur->bc_btnum] &&
 103                be16_to_cpu(block->bb_level) == level &&
 104                be16_to_cpu(block->bb_numrecs) <=
 105                        cur->bc_ops->get_maxrecs(cur, level) &&
 106                (block->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK) ||
 107                 be32_to_cpu(block->bb_u.s.bb_leftsib) < agflen) &&
 108                block->bb_u.s.bb_leftsib &&
 109                (block->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK) ||
 110                 be32_to_cpu(block->bb_u.s.bb_rightsib) < agflen) &&
 111                block->bb_u.s.bb_rightsib;
 112        if (unlikely(XFS_TEST_ERROR(!sblock_ok, cur->bc_mp,
 113                        XFS_ERRTAG_BTREE_CHECK_SBLOCK,
 114                        XFS_RANDOM_BTREE_CHECK_SBLOCK))) {
 115                if (bp)
 116                        trace_xfs_btree_corrupt(bp, _RET_IP_);
 117                XFS_CORRUPTION_ERROR("xfs_btree_check_sblock",
 118                        XFS_ERRLEVEL_LOW, cur->bc_mp, block);
 119                return XFS_ERROR(EFSCORRUPTED);
 120        }
 121        return 0;
 122}
 123
 124/*
 125 * Debug routine: check that block header is ok.
 126 */
 127int
 128xfs_btree_check_block(
 129        struct xfs_btree_cur    *cur,   /* btree cursor */
 130        struct xfs_btree_block  *block, /* generic btree block pointer */
 131        int                     level,  /* level of the btree block */
 132        struct xfs_buf          *bp)    /* buffer containing block, if any */
 133{
 134        if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 135                return xfs_btree_check_lblock(cur, block, level, bp);
 136        else
 137                return xfs_btree_check_sblock(cur, block, level, bp);
 138}
 139
 140/*
 141 * Check that (long) pointer is ok.
 142 */
 143int                                     /* error (0 or EFSCORRUPTED) */
 144xfs_btree_check_lptr(
 145        struct xfs_btree_cur    *cur,   /* btree cursor */
 146        xfs_dfsbno_t            bno,    /* btree block disk address */
 147        int                     level)  /* btree block level */
 148{
 149        XFS_WANT_CORRUPTED_RETURN(
 150                level > 0 &&
 151                bno != NULLDFSBNO &&
 152                XFS_FSB_SANITY_CHECK(cur->bc_mp, bno));
 153        return 0;
 154}
 155
 156#ifdef DEBUG
 157/*
 158 * Check that (short) pointer is ok.
 159 */
 160STATIC int                              /* error (0 or EFSCORRUPTED) */
 161xfs_btree_check_sptr(
 162        struct xfs_btree_cur    *cur,   /* btree cursor */
 163        xfs_agblock_t           bno,    /* btree block disk address */
 164        int                     level)  /* btree block level */
 165{
 166        xfs_agblock_t           agblocks = cur->bc_mp->m_sb.sb_agblocks;
 167
 168        XFS_WANT_CORRUPTED_RETURN(
 169                level > 0 &&
 170                bno != NULLAGBLOCK &&
 171                bno != 0 &&
 172                bno < agblocks);
 173        return 0;
 174}
 175
 176/*
 177 * Check that block ptr is ok.
 178 */
 179STATIC int                              /* error (0 or EFSCORRUPTED) */
 180xfs_btree_check_ptr(
 181        struct xfs_btree_cur    *cur,   /* btree cursor */
 182        union xfs_btree_ptr     *ptr,   /* btree block disk address */
 183        int                     index,  /* offset from ptr to check */
 184        int                     level)  /* btree block level */
 185{
 186        if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 187                return xfs_btree_check_lptr(cur,
 188                                be64_to_cpu((&ptr->l)[index]), level);
 189        } else {
 190                return xfs_btree_check_sptr(cur,
 191                                be32_to_cpu((&ptr->s)[index]), level);
 192        }
 193}
 194#endif
 195
 196/*
 197 * Delete the btree cursor.
 198 */
 199void
 200xfs_btree_del_cursor(
 201        xfs_btree_cur_t *cur,           /* btree cursor */
 202        int             error)          /* del because of error */
 203{
 204        int             i;              /* btree level */
 205
 206        /*
 207         * Clear the buffer pointers, and release the buffers.
 208         * If we're doing this in the face of an error, we
 209         * need to make sure to inspect all of the entries
 210         * in the bc_bufs array for buffers to be unlocked.
 211         * This is because some of the btree code works from
 212         * level n down to 0, and if we get an error along
 213         * the way we won't have initialized all the entries
 214         * down to 0.
 215         */
 216        for (i = 0; i < cur->bc_nlevels; i++) {
 217                if (cur->bc_bufs[i])
 218                        xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[i]);
 219                else if (!error)
 220                        break;
 221        }
 222        /*
 223         * Can't free a bmap cursor without having dealt with the
 224         * allocated indirect blocks' accounting.
 225         */
 226        ASSERT(cur->bc_btnum != XFS_BTNUM_BMAP ||
 227               cur->bc_private.b.allocated == 0);
 228        /*
 229         * Free the cursor.
 230         */
 231        kmem_zone_free(xfs_btree_cur_zone, cur);
 232}
 233
 234/*
 235 * Duplicate the btree cursor.
 236 * Allocate a new one, copy the record, re-get the buffers.
 237 */
 238int                                     /* error */
 239xfs_btree_dup_cursor(
 240        xfs_btree_cur_t *cur,           /* input cursor */
 241        xfs_btree_cur_t **ncur)         /* output cursor */
 242{
 243        xfs_buf_t       *bp;            /* btree block's buffer pointer */
 244        int             error;          /* error return value */
 245        int             i;              /* level number of btree block */
 246        xfs_mount_t     *mp;            /* mount structure for filesystem */
 247        xfs_btree_cur_t *new;           /* new cursor value */
 248        xfs_trans_t     *tp;            /* transaction pointer, can be NULL */
 249
 250        tp = cur->bc_tp;
 251        mp = cur->bc_mp;
 252
 253        /*
 254         * Allocate a new cursor like the old one.
 255         */
 256        new = cur->bc_ops->dup_cursor(cur);
 257
 258        /*
 259         * Copy the record currently in the cursor.
 260         */
 261        new->bc_rec = cur->bc_rec;
 262
 263        /*
 264         * For each level current, re-get the buffer and copy the ptr value.
 265         */
 266        for (i = 0; i < new->bc_nlevels; i++) {
 267                new->bc_ptrs[i] = cur->bc_ptrs[i];
 268                new->bc_ra[i] = cur->bc_ra[i];
 269                if ((bp = cur->bc_bufs[i])) {
 270                        if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
 271                                XFS_BUF_ADDR(bp), mp->m_bsize, 0, &bp))) {
 272                                xfs_btree_del_cursor(new, error);
 273                                *ncur = NULL;
 274                                return error;
 275                        }
 276                        new->bc_bufs[i] = bp;
 277                        ASSERT(!xfs_buf_geterror(bp));
 278                } else
 279                        new->bc_bufs[i] = NULL;
 280        }
 281        *ncur = new;
 282        return 0;
 283}
 284
 285/*
 286 * XFS btree block layout and addressing:
 287 *
 288 * There are two types of blocks in the btree: leaf and non-leaf blocks.
 289 *
 290 * The leaf record start with a header then followed by records containing
 291 * the values.  A non-leaf block also starts with the same header, and
 292 * then first contains lookup keys followed by an equal number of pointers
 293 * to the btree blocks at the previous level.
 294 *
 295 *              +--------+-------+-------+-------+-------+-------+-------+
 296 * Leaf:        | header | rec 1 | rec 2 | rec 3 | rec 4 | rec 5 | rec N |
 297 *              +--------+-------+-------+-------+-------+-------+-------+
 298 *
 299 *              +--------+-------+-------+-------+-------+-------+-------+
 300 * Non-Leaf:    | header | key 1 | key 2 | key N | ptr 1 | ptr 2 | ptr N |
 301 *              +--------+-------+-------+-------+-------+-------+-------+
 302 *
 303 * The header is called struct xfs_btree_block for reasons better left unknown
 304 * and comes in different versions for short (32bit) and long (64bit) block
 305 * pointers.  The record and key structures are defined by the btree instances
 306 * and opaque to the btree core.  The block pointers are simple disk endian
 307 * integers, available in a short (32bit) and long (64bit) variant.
 308 *
 309 * The helpers below calculate the offset of a given record, key or pointer
 310 * into a btree block (xfs_btree_*_offset) or return a pointer to the given
 311 * record, key or pointer (xfs_btree_*_addr).  Note that all addressing
 312 * inside the btree block is done using indices starting at one, not zero!
 313 */
 314
 315/*
 316 * Return size of the btree block header for this btree instance.
 317 */
 318static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur)
 319{
 320        return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
 321                XFS_BTREE_LBLOCK_LEN :
 322                XFS_BTREE_SBLOCK_LEN;
 323}
 324
 325/*
 326 * Return size of btree block pointers for this btree instance.
 327 */
 328static inline size_t xfs_btree_ptr_len(struct xfs_btree_cur *cur)
 329{
 330        return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
 331                sizeof(__be64) : sizeof(__be32);
 332}
 333
 334/*
 335 * Calculate offset of the n-th record in a btree block.
 336 */
 337STATIC size_t
 338xfs_btree_rec_offset(
 339        struct xfs_btree_cur    *cur,
 340        int                     n)
 341{
 342        return xfs_btree_block_len(cur) +
 343                (n - 1) * cur->bc_ops->rec_len;
 344}
 345
 346/*
 347 * Calculate offset of the n-th key in a btree block.
 348 */
 349STATIC size_t
 350xfs_btree_key_offset(
 351        struct xfs_btree_cur    *cur,
 352        int                     n)
 353{
 354        return xfs_btree_block_len(cur) +
 355                (n - 1) * cur->bc_ops->key_len;
 356}
 357
 358/*
 359 * Calculate offset of the n-th block pointer in a btree block.
 360 */
 361STATIC size_t
 362xfs_btree_ptr_offset(
 363        struct xfs_btree_cur    *cur,
 364        int                     n,
 365        int                     level)
 366{
 367        return xfs_btree_block_len(cur) +
 368                cur->bc_ops->get_maxrecs(cur, level) * cur->bc_ops->key_len +
 369                (n - 1) * xfs_btree_ptr_len(cur);
 370}
 371
 372/*
 373 * Return a pointer to the n-th record in the btree block.
 374 */
 375STATIC union xfs_btree_rec *
 376xfs_btree_rec_addr(
 377        struct xfs_btree_cur    *cur,
 378        int                     n,
 379        struct xfs_btree_block  *block)
 380{
 381        return (union xfs_btree_rec *)
 382                ((char *)block + xfs_btree_rec_offset(cur, n));
 383}
 384
 385/*
 386 * Return a pointer to the n-th key in the btree block.
 387 */
 388STATIC union xfs_btree_key *
 389xfs_btree_key_addr(
 390        struct xfs_btree_cur    *cur,
 391        int                     n,
 392        struct xfs_btree_block  *block)
 393{
 394        return (union xfs_btree_key *)
 395                ((char *)block + xfs_btree_key_offset(cur, n));
 396}
 397
 398/*
 399 * Return a pointer to the n-th block pointer in the btree block.
 400 */
 401STATIC union xfs_btree_ptr *
 402xfs_btree_ptr_addr(
 403        struct xfs_btree_cur    *cur,
 404        int                     n,
 405        struct xfs_btree_block  *block)
 406{
 407        int                     level = xfs_btree_get_level(block);
 408
 409        ASSERT(block->bb_level != 0);
 410
 411        return (union xfs_btree_ptr *)
 412                ((char *)block + xfs_btree_ptr_offset(cur, n, level));
 413}
 414
 415/*
 416 * Get a the root block which is stored in the inode.
 417 *
 418 * For now this btree implementation assumes the btree root is always
 419 * stored in the if_broot field of an inode fork.
 420 */
 421STATIC struct xfs_btree_block *
 422xfs_btree_get_iroot(
 423       struct xfs_btree_cur    *cur)
 424{
 425       struct xfs_ifork        *ifp;
 426
 427       ifp = XFS_IFORK_PTR(cur->bc_private.b.ip, cur->bc_private.b.whichfork);
 428       return (struct xfs_btree_block *)ifp->if_broot;
 429}
 430
 431/*
 432 * Retrieve the block pointer from the cursor at the given level.
 433 * This may be an inode btree root or from a buffer.
 434 */
 435STATIC struct xfs_btree_block *         /* generic btree block pointer */
 436xfs_btree_get_block(
 437        struct xfs_btree_cur    *cur,   /* btree cursor */
 438        int                     level,  /* level in btree */
 439        struct xfs_buf          **bpp)  /* buffer containing the block */
 440{
 441        if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
 442            (level == cur->bc_nlevels - 1)) {
 443                *bpp = NULL;
 444                return xfs_btree_get_iroot(cur);
 445        }
 446
 447        *bpp = cur->bc_bufs[level];
 448        return XFS_BUF_TO_BLOCK(*bpp);
 449}
 450
 451/*
 452 * Get a buffer for the block, return it with no data read.
 453 * Long-form addressing.
 454 */
 455xfs_buf_t *                             /* buffer for fsbno */
 456xfs_btree_get_bufl(
 457        xfs_mount_t     *mp,            /* file system mount point */
 458        xfs_trans_t     *tp,            /* transaction pointer */
 459        xfs_fsblock_t   fsbno,          /* file system block number */
 460        uint            lock)           /* lock flags for get_buf */
 461{
 462        xfs_buf_t       *bp;            /* buffer pointer (return value) */
 463        xfs_daddr_t             d;              /* real disk block address */
 464
 465        ASSERT(fsbno != NULLFSBLOCK);
 466        d = XFS_FSB_TO_DADDR(mp, fsbno);
 467        bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, lock);
 468        ASSERT(!xfs_buf_geterror(bp));
 469        return bp;
 470}
 471
 472/*
 473 * Get a buffer for the block, return it with no data read.
 474 * Short-form addressing.
 475 */
 476xfs_buf_t *                             /* buffer for agno/agbno */
 477xfs_btree_get_bufs(
 478        xfs_mount_t     *mp,            /* file system mount point */
 479        xfs_trans_t     *tp,            /* transaction pointer */
 480        xfs_agnumber_t  agno,           /* allocation group number */
 481        xfs_agblock_t   agbno,          /* allocation group block number */
 482        uint            lock)           /* lock flags for get_buf */
 483{
 484        xfs_buf_t       *bp;            /* buffer pointer (return value) */
 485        xfs_daddr_t             d;              /* real disk block address */
 486
 487        ASSERT(agno != NULLAGNUMBER);
 488        ASSERT(agbno != NULLAGBLOCK);
 489        d = XFS_AGB_TO_DADDR(mp, agno, agbno);
 490        bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d, mp->m_bsize, lock);
 491        ASSERT(!xfs_buf_geterror(bp));
 492        return bp;
 493}
 494
 495/*
 496 * Check for the cursor referring to the last block at the given level.
 497 */
 498int                                     /* 1=is last block, 0=not last block */
 499xfs_btree_islastblock(
 500        xfs_btree_cur_t         *cur,   /* btree cursor */
 501        int                     level)  /* level to check */
 502{
 503        struct xfs_btree_block  *block; /* generic btree block pointer */
 504        xfs_buf_t               *bp;    /* buffer containing block */
 505
 506        block = xfs_btree_get_block(cur, level, &bp);
 507        xfs_btree_check_block(cur, block, level, bp);
 508        if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 509                return block->bb_u.l.bb_rightsib == cpu_to_be64(NULLDFSBNO);
 510        else
 511                return block->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK);
 512}
 513
 514/*
 515 * Change the cursor to point to the first record at the given level.
 516 * Other levels are unaffected.
 517 */
 518STATIC int                              /* success=1, failure=0 */
 519xfs_btree_firstrec(
 520        xfs_btree_cur_t         *cur,   /* btree cursor */
 521        int                     level)  /* level to change */
 522{
 523        struct xfs_btree_block  *block; /* generic btree block pointer */
 524        xfs_buf_t               *bp;    /* buffer containing block */
 525
 526        /*
 527         * Get the block pointer for this level.
 528         */
 529        block = xfs_btree_get_block(cur, level, &bp);
 530        xfs_btree_check_block(cur, block, level, bp);
 531        /*
 532         * It's empty, there is no such record.
 533         */
 534        if (!block->bb_numrecs)
 535                return 0;
 536        /*
 537         * Set the ptr value to 1, that's the first record/key.
 538         */
 539        cur->bc_ptrs[level] = 1;
 540        return 1;
 541}
 542
 543/*
 544 * Change the cursor to point to the last record in the current block
 545 * at the given level.  Other levels are unaffected.
 546 */
 547STATIC int                              /* success=1, failure=0 */
 548xfs_btree_lastrec(
 549        xfs_btree_cur_t         *cur,   /* btree cursor */
 550        int                     level)  /* level to change */
 551{
 552        struct xfs_btree_block  *block; /* generic btree block pointer */
 553        xfs_buf_t               *bp;    /* buffer containing block */
 554
 555        /*
 556         * Get the block pointer for this level.
 557         */
 558        block = xfs_btree_get_block(cur, level, &bp);
 559        xfs_btree_check_block(cur, block, level, bp);
 560        /*
 561         * It's empty, there is no such record.
 562         */
 563        if (!block->bb_numrecs)
 564                return 0;
 565        /*
 566         * Set the ptr value to numrecs, that's the last record/key.
 567         */
 568        cur->bc_ptrs[level] = be16_to_cpu(block->bb_numrecs);
 569        return 1;
 570}
 571
 572/*
 573 * Compute first and last byte offsets for the fields given.
 574 * Interprets the offsets table, which contains struct field offsets.
 575 */
 576void
 577xfs_btree_offsets(
 578        __int64_t       fields,         /* bitmask of fields */
 579        const short     *offsets,       /* table of field offsets */
 580        int             nbits,          /* number of bits to inspect */
 581        int             *first,         /* output: first byte offset */
 582        int             *last)          /* output: last byte offset */
 583{
 584        int             i;              /* current bit number */
 585        __int64_t       imask;          /* mask for current bit number */
 586
 587        ASSERT(fields != 0);
 588        /*
 589         * Find the lowest bit, so the first byte offset.
 590         */
 591        for (i = 0, imask = 1LL; ; i++, imask <<= 1) {
 592                if (imask & fields) {
 593                        *first = offsets[i];
 594                        break;
 595                }
 596        }
 597        /*
 598         * Find the highest bit, so the last byte offset.
 599         */
 600        for (i = nbits - 1, imask = 1LL << i; ; i--, imask >>= 1) {
 601                if (imask & fields) {
 602                        *last = offsets[i + 1] - 1;
 603                        break;
 604                }
 605        }
 606}
 607
 608/*
 609 * Get a buffer for the block, return it read in.
 610 * Long-form addressing.
 611 */
 612int                                     /* error */
 613xfs_btree_read_bufl(
 614        xfs_mount_t     *mp,            /* file system mount point */
 615        xfs_trans_t     *tp,            /* transaction pointer */
 616        xfs_fsblock_t   fsbno,          /* file system block number */
 617        uint            lock,           /* lock flags for read_buf */
 618        xfs_buf_t       **bpp,          /* buffer for fsbno */
 619        int             refval)         /* ref count value for buffer */
 620{
 621        xfs_buf_t       *bp;            /* return value */
 622        xfs_daddr_t             d;              /* real disk block address */
 623        int             error;
 624
 625        ASSERT(fsbno != NULLFSBLOCK);
 626        d = XFS_FSB_TO_DADDR(mp, fsbno);
 627        if ((error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
 628                        mp->m_bsize, lock, &bp))) {
 629                return error;
 630        }
 631        ASSERT(!xfs_buf_geterror(bp));
 632        if (bp)
 633                xfs_buf_set_ref(bp, refval);
 634        *bpp = bp;
 635        return 0;
 636}
 637
 638/*
 639 * Read-ahead the block, don't wait for it, don't return a buffer.
 640 * Long-form addressing.
 641 */
 642/* ARGSUSED */
 643void
 644xfs_btree_reada_bufl(
 645        xfs_mount_t     *mp,            /* file system mount point */
 646        xfs_fsblock_t   fsbno,          /* file system block number */
 647        xfs_extlen_t    count)          /* count of filesystem blocks */
 648{
 649        xfs_daddr_t             d;
 650
 651        ASSERT(fsbno != NULLFSBLOCK);
 652        d = XFS_FSB_TO_DADDR(mp, fsbno);
 653        xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count);
 654}
 655
 656/*
 657 * Read-ahead the block, don't wait for it, don't return a buffer.
 658 * Short-form addressing.
 659 */
 660/* ARGSUSED */
 661void
 662xfs_btree_reada_bufs(
 663        xfs_mount_t     *mp,            /* file system mount point */
 664        xfs_agnumber_t  agno,           /* allocation group number */
 665        xfs_agblock_t   agbno,          /* allocation group block number */
 666        xfs_extlen_t    count)          /* count of filesystem blocks */
 667{
 668        xfs_daddr_t             d;
 669
 670        ASSERT(agno != NULLAGNUMBER);
 671        ASSERT(agbno != NULLAGBLOCK);
 672        d = XFS_AGB_TO_DADDR(mp, agno, agbno);
 673        xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count);
 674}
 675
 676STATIC int
 677xfs_btree_readahead_lblock(
 678        struct xfs_btree_cur    *cur,
 679        int                     lr,
 680        struct xfs_btree_block  *block)
 681{
 682        int                     rval = 0;
 683        xfs_dfsbno_t            left = be64_to_cpu(block->bb_u.l.bb_leftsib);
 684        xfs_dfsbno_t            right = be64_to_cpu(block->bb_u.l.bb_rightsib);
 685
 686        if ((lr & XFS_BTCUR_LEFTRA) && left != NULLDFSBNO) {
 687                xfs_btree_reada_bufl(cur->bc_mp, left, 1);
 688                rval++;
 689        }
 690
 691        if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLDFSBNO) {
 692                xfs_btree_reada_bufl(cur->bc_mp, right, 1);
 693                rval++;
 694        }
 695
 696        return rval;
 697}
 698
 699STATIC int
 700xfs_btree_readahead_sblock(
 701        struct xfs_btree_cur    *cur,
 702        int                     lr,
 703        struct xfs_btree_block *block)
 704{
 705        int                     rval = 0;
 706        xfs_agblock_t           left = be32_to_cpu(block->bb_u.s.bb_leftsib);
 707        xfs_agblock_t           right = be32_to_cpu(block->bb_u.s.bb_rightsib);
 708
 709
 710        if ((lr & XFS_BTCUR_LEFTRA) && left != NULLAGBLOCK) {
 711                xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
 712                                     left, 1);
 713                rval++;
 714        }
 715
 716        if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {
 717                xfs_btree_reada_bufs(cur->bc_mp, cur->bc_private.a.agno,
 718                                     right, 1);
 719                rval++;
 720        }
 721
 722        return rval;
 723}
 724
 725/*
 726 * Read-ahead btree blocks, at the given level.
 727 * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
 728 */
 729STATIC int
 730xfs_btree_readahead(
 731        struct xfs_btree_cur    *cur,           /* btree cursor */
 732        int                     lev,            /* level in btree */
 733        int                     lr)             /* left/right bits */
 734{
 735        struct xfs_btree_block  *block;
 736
 737        /*
 738         * No readahead needed if we are at the root level and the
 739         * btree root is stored in the inode.
 740         */
 741        if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
 742            (lev == cur->bc_nlevels - 1))
 743                return 0;
 744
 745        if ((cur->bc_ra[lev] | lr) == cur->bc_ra[lev])
 746                return 0;
 747
 748        cur->bc_ra[lev] |= lr;
 749        block = XFS_BUF_TO_BLOCK(cur->bc_bufs[lev]);
 750
 751        if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 752                return xfs_btree_readahead_lblock(cur, lr, block);
 753        return xfs_btree_readahead_sblock(cur, lr, block);
 754}
 755
 756/*
 757 * Set the buffer for level "lev" in the cursor to bp, releasing
 758 * any previous buffer.
 759 */
 760STATIC void
 761xfs_btree_setbuf(
 762        xfs_btree_cur_t         *cur,   /* btree cursor */
 763        int                     lev,    /* level in btree */
 764        xfs_buf_t               *bp)    /* new buffer to set */
 765{
 766        struct xfs_btree_block  *b;     /* btree block */
 767
 768        if (cur->bc_bufs[lev])
 769                xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[lev]);
 770        cur->bc_bufs[lev] = bp;
 771        cur->bc_ra[lev] = 0;
 772
 773        b = XFS_BUF_TO_BLOCK(bp);
 774        if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 775                if (b->bb_u.l.bb_leftsib == cpu_to_be64(NULLDFSBNO))
 776                        cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
 777                if (b->bb_u.l.bb_rightsib == cpu_to_be64(NULLDFSBNO))
 778                        cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
 779        } else {
 780                if (b->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK))
 781                        cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
 782                if (b->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK))
 783                        cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
 784        }
 785}
 786
 787STATIC int
 788xfs_btree_ptr_is_null(
 789        struct xfs_btree_cur    *cur,
 790        union xfs_btree_ptr     *ptr)
 791{
 792        if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 793                return ptr->l == cpu_to_be64(NULLDFSBNO);
 794        else
 795                return ptr->s == cpu_to_be32(NULLAGBLOCK);
 796}
 797
 798STATIC void
 799xfs_btree_set_ptr_null(
 800        struct xfs_btree_cur    *cur,
 801        union xfs_btree_ptr     *ptr)
 802{
 803        if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 804                ptr->l = cpu_to_be64(NULLDFSBNO);
 805        else
 806                ptr->s = cpu_to_be32(NULLAGBLOCK);
 807}
 808
 809/*
 810 * Get/set/init sibling pointers
 811 */
 812STATIC void
 813xfs_btree_get_sibling(
 814        struct xfs_btree_cur    *cur,
 815        struct xfs_btree_block  *block,
 816        union xfs_btree_ptr     *ptr,
 817        int                     lr)
 818{
 819        ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
 820
 821        if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 822                if (lr == XFS_BB_RIGHTSIB)
 823                        ptr->l = block->bb_u.l.bb_rightsib;
 824                else
 825                        ptr->l = block->bb_u.l.bb_leftsib;
 826        } else {
 827                if (lr == XFS_BB_RIGHTSIB)
 828                        ptr->s = block->bb_u.s.bb_rightsib;
 829                else
 830                        ptr->s = block->bb_u.s.bb_leftsib;
 831        }
 832}
 833
 834STATIC void
 835xfs_btree_set_sibling(
 836        struct xfs_btree_cur    *cur,
 837        struct xfs_btree_block  *block,
 838        union xfs_btree_ptr     *ptr,
 839        int                     lr)
 840{
 841        ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
 842
 843        if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 844                if (lr == XFS_BB_RIGHTSIB)
 845                        block->bb_u.l.bb_rightsib = ptr->l;
 846                else
 847                        block->bb_u.l.bb_leftsib = ptr->l;
 848        } else {
 849                if (lr == XFS_BB_RIGHTSIB)
 850                        block->bb_u.s.bb_rightsib = ptr->s;
 851                else
 852                        block->bb_u.s.bb_leftsib = ptr->s;
 853        }
 854}
 855
 856STATIC void
 857xfs_btree_init_block(
 858        struct xfs_btree_cur    *cur,
 859        int                     level,
 860        int                     numrecs,
 861        struct xfs_btree_block  *new)   /* new block */
 862{
 863        new->bb_magic = cpu_to_be32(xfs_magics[cur->bc_btnum]);
 864        new->bb_level = cpu_to_be16(level);
 865        new->bb_numrecs = cpu_to_be16(numrecs);
 866
 867        if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 868                new->bb_u.l.bb_leftsib = cpu_to_be64(NULLDFSBNO);
 869                new->bb_u.l.bb_rightsib = cpu_to_be64(NULLDFSBNO);
 870        } else {
 871                new->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
 872                new->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
 873        }
 874}
 875
 876/*
 877 * Return true if ptr is the last record in the btree and
 878 * we need to track updateѕ to this record.  The decision
 879 * will be further refined in the update_lastrec method.
 880 */
 881STATIC int
 882xfs_btree_is_lastrec(
 883        struct xfs_btree_cur    *cur,
 884        struct xfs_btree_block  *block,
 885        int                     level)
 886{
 887        union xfs_btree_ptr     ptr;
 888
 889        if (level > 0)
 890                return 0;
 891        if (!(cur->bc_flags & XFS_BTREE_LASTREC_UPDATE))
 892                return 0;
 893
 894        xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
 895        if (!xfs_btree_ptr_is_null(cur, &ptr))
 896                return 0;
 897        return 1;
 898}
 899
 900STATIC void
 901xfs_btree_buf_to_ptr(
 902        struct xfs_btree_cur    *cur,
 903        struct xfs_buf          *bp,
 904        union xfs_btree_ptr     *ptr)
 905{
 906        if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 907                ptr->l = cpu_to_be64(XFS_DADDR_TO_FSB(cur->bc_mp,
 908                                        XFS_BUF_ADDR(bp)));
 909        else {
 910                ptr->s = cpu_to_be32(xfs_daddr_to_agbno(cur->bc_mp,
 911                                        XFS_BUF_ADDR(bp)));
 912        }
 913}
 914
 915STATIC xfs_daddr_t
 916xfs_btree_ptr_to_daddr(
 917        struct xfs_btree_cur    *cur,
 918        union xfs_btree_ptr     *ptr)
 919{
 920        if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 921                ASSERT(ptr->l != cpu_to_be64(NULLDFSBNO));
 922
 923                return XFS_FSB_TO_DADDR(cur->bc_mp, be64_to_cpu(ptr->l));
 924        } else {
 925                ASSERT(cur->bc_private.a.agno != NULLAGNUMBER);
 926                ASSERT(ptr->s != cpu_to_be32(NULLAGBLOCK));
 927
 928                return XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_private.a.agno,
 929                                        be32_to_cpu(ptr->s));
 930        }
 931}
 932
 933STATIC void
 934xfs_btree_set_refs(
 935        struct xfs_btree_cur    *cur,
 936        struct xfs_buf          *bp)
 937{
 938        switch (cur->bc_btnum) {
 939        case XFS_BTNUM_BNO:
 940        case XFS_BTNUM_CNT:
 941                xfs_buf_set_ref(bp, XFS_ALLOC_BTREE_REF);
 942                break;
 943        case XFS_BTNUM_INO:
 944                xfs_buf_set_ref(bp, XFS_INO_BTREE_REF);
 945                break;
 946        case XFS_BTNUM_BMAP:
 947                xfs_buf_set_ref(bp, XFS_BMAP_BTREE_REF);
 948                break;
 949        default:
 950                ASSERT(0);
 951        }
 952}
 953
 954STATIC int
 955xfs_btree_get_buf_block(
 956        struct xfs_btree_cur    *cur,
 957        union xfs_btree_ptr     *ptr,
 958        int                     flags,
 959        struct xfs_btree_block  **block,
 960        struct xfs_buf          **bpp)
 961{
 962        struct xfs_mount        *mp = cur->bc_mp;
 963        xfs_daddr_t             d;
 964
 965        /* need to sort out how callers deal with failures first */
 966        ASSERT(!(flags & XBF_TRYLOCK));
 967
 968        d = xfs_btree_ptr_to_daddr(cur, ptr);
 969        *bpp = xfs_trans_get_buf(cur->bc_tp, mp->m_ddev_targp, d,
 970                                 mp->m_bsize, flags);
 971
 972        if (!*bpp)
 973                return ENOMEM;
 974
 975        *block = XFS_BUF_TO_BLOCK(*bpp);
 976        return 0;
 977}
 978
 979/*
 980 * Read in the buffer at the given ptr and return the buffer and
 981 * the block pointer within the buffer.
 982 */
 983STATIC int
 984xfs_btree_read_buf_block(
 985        struct xfs_btree_cur    *cur,
 986        union xfs_btree_ptr     *ptr,
 987        int                     level,
 988        int                     flags,
 989        struct xfs_btree_block  **block,
 990        struct xfs_buf          **bpp)
 991{
 992        struct xfs_mount        *mp = cur->bc_mp;
 993        xfs_daddr_t             d;
 994        int                     error;
 995
 996        /* need to sort out how callers deal with failures first */
 997        ASSERT(!(flags & XBF_TRYLOCK));
 998
 999        d = xfs_btree_ptr_to_daddr(cur, ptr);
1000        error = xfs_trans_read_buf(mp, cur->bc_tp, mp->m_ddev_targp, d,
1001                                   mp->m_bsize, flags, bpp);
1002        if (error)
1003                return error;
1004
1005        ASSERT(!xfs_buf_geterror(*bpp));
1006
1007        xfs_btree_set_refs(cur, *bpp);
1008        *block = XFS_BUF_TO_BLOCK(*bpp);
1009
1010        error = xfs_btree_check_block(cur, *block, level, *bpp);
1011        if (error)
1012                xfs_trans_brelse(cur->bc_tp, *bpp);
1013        return error;
1014}
1015
1016/*
1017 * Copy keys from one btree block to another.
1018 */
1019STATIC void
1020xfs_btree_copy_keys(
1021        struct xfs_btree_cur    *cur,
1022        union xfs_btree_key     *dst_key,
1023        union xfs_btree_key     *src_key,
1024        int                     numkeys)
1025{
1026        ASSERT(numkeys >= 0);
1027        memcpy(dst_key, src_key, numkeys * cur->bc_ops->key_len);
1028}
1029
1030/*
1031 * Copy records from one btree block to another.
1032 */
1033STATIC void
1034xfs_btree_copy_recs(
1035        struct xfs_btree_cur    *cur,
1036        union xfs_btree_rec     *dst_rec,
1037        union xfs_btree_rec     *src_rec,
1038        int                     numrecs)
1039{
1040        ASSERT(numrecs >= 0);
1041        memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
1042}
1043
1044/*
1045 * Copy block pointers from one btree block to another.
1046 */
1047STATIC void
1048xfs_btree_copy_ptrs(
1049        struct xfs_btree_cur    *cur,
1050        union xfs_btree_ptr     *dst_ptr,
1051        union xfs_btree_ptr     *src_ptr,
1052        int                     numptrs)
1053{
1054        ASSERT(numptrs >= 0);
1055        memcpy(dst_ptr, src_ptr, numptrs * xfs_btree_ptr_len(cur));
1056}
1057
1058/*
1059 * Shift keys one index left/right inside a single btree block.
1060 */
1061STATIC void
1062xfs_btree_shift_keys(
1063        struct xfs_btree_cur    *cur,
1064        union xfs_btree_key     *key,
1065        int                     dir,
1066        int                     numkeys)
1067{
1068        char                    *dst_key;
1069
1070        ASSERT(numkeys >= 0);
1071        ASSERT(dir == 1 || dir == -1);
1072
1073        dst_key = (char *)key + (dir * cur->bc_ops->key_len);
1074        memmove(dst_key, key, numkeys * cur->bc_ops->key_len);
1075}
1076
1077/*
1078 * Shift records one index left/right inside a single btree block.
1079 */
1080STATIC void
1081xfs_btree_shift_recs(
1082        struct xfs_btree_cur    *cur,
1083        union xfs_btree_rec     *rec,
1084        int                     dir,
1085        int                     numrecs)
1086{
1087        char                    *dst_rec;
1088
1089        ASSERT(numrecs >= 0);
1090        ASSERT(dir == 1 || dir == -1);
1091
1092        dst_rec = (char *)rec + (dir * cur->bc_ops->rec_len);
1093        memmove(dst_rec, rec, numrecs * cur->bc_ops->rec_len);
1094}
1095
1096/*
1097 * Shift block pointers one index left/right inside a single btree block.
1098 */
1099STATIC void
1100xfs_btree_shift_ptrs(
1101        struct xfs_btree_cur    *cur,
1102        union xfs_btree_ptr     *ptr,
1103        int                     dir,
1104        int                     numptrs)
1105{
1106        char                    *dst_ptr;
1107
1108        ASSERT(numptrs >= 0);
1109        ASSERT(dir == 1 || dir == -1);
1110
1111        dst_ptr = (char *)ptr + (dir * xfs_btree_ptr_len(cur));
1112        memmove(dst_ptr, ptr, numptrs * xfs_btree_ptr_len(cur));
1113}
1114
1115/*
1116 * Log key values from the btree block.
1117 */
1118STATIC void
1119xfs_btree_log_keys(
1120        struct xfs_btree_cur    *cur,
1121        struct xfs_buf          *bp,
1122        int                     first,
1123        int                     last)
1124{
1125        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1126        XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
1127
1128        if (bp) {
1129                xfs_trans_log_buf(cur->bc_tp, bp,
1130                                  xfs_btree_key_offset(cur, first),
1131                                  xfs_btree_key_offset(cur, last + 1) - 1);
1132        } else {
1133                xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1134                                xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1135        }
1136
1137        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1138}
1139
1140/*
1141 * Log record values from the btree block.
1142 */
1143void
1144xfs_btree_log_recs(
1145        struct xfs_btree_cur    *cur,
1146        struct xfs_buf          *bp,
1147        int                     first,
1148        int                     last)
1149{
1150        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1151        XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
1152
1153        xfs_trans_log_buf(cur->bc_tp, bp,
1154                          xfs_btree_rec_offset(cur, first),
1155                          xfs_btree_rec_offset(cur, last + 1) - 1);
1156
1157        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1158}
1159
1160/*
1161 * Log block pointer fields from a btree block (nonleaf).
1162 */
1163STATIC void
1164xfs_btree_log_ptrs(
1165        struct xfs_btree_cur    *cur,   /* btree cursor */
1166        struct xfs_buf          *bp,    /* buffer containing btree block */
1167        int                     first,  /* index of first pointer to log */
1168        int                     last)   /* index of last pointer to log */
1169{
1170        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1171        XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
1172
1173        if (bp) {
1174                struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
1175                int                     level = xfs_btree_get_level(block);
1176
1177                xfs_trans_log_buf(cur->bc_tp, bp,
1178                                xfs_btree_ptr_offset(cur, first, level),
1179                                xfs_btree_ptr_offset(cur, last + 1, level) - 1);
1180        } else {
1181                xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1182                        xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1183        }
1184
1185        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1186}
1187
1188/*
1189 * Log fields from a btree block header.
1190 */
1191void
1192xfs_btree_log_block(
1193        struct xfs_btree_cur    *cur,   /* btree cursor */
1194        struct xfs_buf          *bp,    /* buffer containing btree block */
1195        int                     fields) /* mask of fields: XFS_BB_... */
1196{
1197        int                     first;  /* first byte offset logged */
1198        int                     last;   /* last byte offset logged */
1199        static const short      soffsets[] = {  /* table of offsets (short) */
1200                offsetof(struct xfs_btree_block, bb_magic),
1201                offsetof(struct xfs_btree_block, bb_level),
1202                offsetof(struct xfs_btree_block, bb_numrecs),
1203                offsetof(struct xfs_btree_block, bb_u.s.bb_leftsib),
1204                offsetof(struct xfs_btree_block, bb_u.s.bb_rightsib),
1205                XFS_BTREE_SBLOCK_LEN
1206        };
1207        static const short      loffsets[] = {  /* table of offsets (long) */
1208                offsetof(struct xfs_btree_block, bb_magic),
1209                offsetof(struct xfs_btree_block, bb_level),
1210                offsetof(struct xfs_btree_block, bb_numrecs),
1211                offsetof(struct xfs_btree_block, bb_u.l.bb_leftsib),
1212                offsetof(struct xfs_btree_block, bb_u.l.bb_rightsib),
1213                XFS_BTREE_LBLOCK_LEN
1214        };
1215
1216        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1217        XFS_BTREE_TRACE_ARGBI(cur, bp, fields);
1218
1219        if (bp) {
1220                xfs_btree_offsets(fields,
1221                                  (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
1222                                        loffsets : soffsets,
1223                                  XFS_BB_NUM_BITS, &first, &last);
1224                xfs_trans_log_buf(cur->bc_tp, bp, first, last);
1225        } else {
1226                xfs_trans_log_inode(cur->bc_tp, cur->bc_private.b.ip,
1227                        xfs_ilog_fbroot(cur->bc_private.b.whichfork));
1228        }
1229
1230        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1231}
1232
1233/*
1234 * Increment cursor by one record at the level.
1235 * For nonzero levels the leaf-ward information is untouched.
1236 */
1237int                                             /* error */
1238xfs_btree_increment(
1239        struct xfs_btree_cur    *cur,
1240        int                     level,
1241        int                     *stat)          /* success/failure */
1242{
1243        struct xfs_btree_block  *block;
1244        union xfs_btree_ptr     ptr;
1245        struct xfs_buf          *bp;
1246        int                     error;          /* error return value */
1247        int                     lev;
1248
1249        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1250        XFS_BTREE_TRACE_ARGI(cur, level);
1251
1252        ASSERT(level < cur->bc_nlevels);
1253
1254        /* Read-ahead to the right at this level. */
1255        xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
1256
1257        /* Get a pointer to the btree block. */
1258        block = xfs_btree_get_block(cur, level, &bp);
1259
1260#ifdef DEBUG
1261        error = xfs_btree_check_block(cur, block, level, bp);
1262        if (error)
1263                goto error0;
1264#endif
1265
1266        /* We're done if we remain in the block after the increment. */
1267        if (++cur->bc_ptrs[level] <= xfs_btree_get_numrecs(block))
1268                goto out1;
1269
1270        /* Fail if we just went off the right edge of the tree. */
1271        xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1272        if (xfs_btree_ptr_is_null(cur, &ptr))
1273                goto out0;
1274
1275        XFS_BTREE_STATS_INC(cur, increment);
1276
1277        /*
1278         * March up the tree incrementing pointers.
1279         * Stop when we don't go off the right edge of a block.
1280         */
1281        for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1282                block = xfs_btree_get_block(cur, lev, &bp);
1283
1284#ifdef DEBUG
1285                error = xfs_btree_check_block(cur, block, lev, bp);
1286                if (error)
1287                        goto error0;
1288#endif
1289
1290                if (++cur->bc_ptrs[lev] <= xfs_btree_get_numrecs(block))
1291                        break;
1292
1293                /* Read-ahead the right block for the next loop. */
1294                xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);
1295        }
1296
1297        /*
1298         * If we went off the root then we are either seriously
1299         * confused or have the tree root in an inode.
1300         */
1301        if (lev == cur->bc_nlevels) {
1302                if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1303                        goto out0;
1304                ASSERT(0);
1305                error = EFSCORRUPTED;
1306                goto error0;
1307        }
1308        ASSERT(lev < cur->bc_nlevels);
1309
1310        /*
1311         * Now walk back down the tree, fixing up the cursor's buffer
1312         * pointers and key numbers.
1313         */
1314        for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1315                union xfs_btree_ptr     *ptrp;
1316
1317                ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
1318                error = xfs_btree_read_buf_block(cur, ptrp, --lev,
1319                                                        0, &block, &bp);
1320                if (error)
1321                        goto error0;
1322
1323                xfs_btree_setbuf(cur, lev, bp);
1324                cur->bc_ptrs[lev] = 1;
1325        }
1326out1:
1327        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1328        *stat = 1;
1329        return 0;
1330
1331out0:
1332        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1333        *stat = 0;
1334        return 0;
1335
1336error0:
1337        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1338        return error;
1339}
1340
1341/*
1342 * Decrement cursor by one record at the level.
1343 * For nonzero levels the leaf-ward information is untouched.
1344 */
1345int                                             /* error */
1346xfs_btree_decrement(
1347        struct xfs_btree_cur    *cur,
1348        int                     level,
1349        int                     *stat)          /* success/failure */
1350{
1351        struct xfs_btree_block  *block;
1352        xfs_buf_t               *bp;
1353        int                     error;          /* error return value */
1354        int                     lev;
1355        union xfs_btree_ptr     ptr;
1356
1357        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1358        XFS_BTREE_TRACE_ARGI(cur, level);
1359
1360        ASSERT(level < cur->bc_nlevels);
1361
1362        /* Read-ahead to the left at this level. */
1363        xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);
1364
1365        /* We're done if we remain in the block after the decrement. */
1366        if (--cur->bc_ptrs[level] > 0)
1367                goto out1;
1368
1369        /* Get a pointer to the btree block. */
1370        block = xfs_btree_get_block(cur, level, &bp);
1371
1372#ifdef DEBUG
1373        error = xfs_btree_check_block(cur, block, level, bp);
1374        if (error)
1375                goto error0;
1376#endif
1377
1378        /* Fail if we just went off the left edge of the tree. */
1379        xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
1380        if (xfs_btree_ptr_is_null(cur, &ptr))
1381                goto out0;
1382
1383        XFS_BTREE_STATS_INC(cur, decrement);
1384
1385        /*
1386         * March up the tree decrementing pointers.
1387         * Stop when we don't go off the left edge of a block.
1388         */
1389        for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1390                if (--cur->bc_ptrs[lev] > 0)
1391                        break;
1392                /* Read-ahead the left block for the next loop. */
1393                xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);
1394        }
1395
1396        /*
1397         * If we went off the root then we are seriously confused.
1398         * or the root of the tree is in an inode.
1399         */
1400        if (lev == cur->bc_nlevels) {
1401                if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1402                        goto out0;
1403                ASSERT(0);
1404                error = EFSCORRUPTED;
1405                goto error0;
1406        }
1407        ASSERT(lev < cur->bc_nlevels);
1408
1409        /*
1410         * Now walk back down the tree, fixing up the cursor's buffer
1411         * pointers and key numbers.
1412         */
1413        for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1414                union xfs_btree_ptr     *ptrp;
1415
1416                ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
1417                error = xfs_btree_read_buf_block(cur, ptrp, --lev,
1418                                                        0, &block, &bp);
1419                if (error)
1420                        goto error0;
1421                xfs_btree_setbuf(cur, lev, bp);
1422                cur->bc_ptrs[lev] = xfs_btree_get_numrecs(block);
1423        }
1424out1:
1425        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1426        *stat = 1;
1427        return 0;
1428
1429out0:
1430        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1431        *stat = 0;
1432        return 0;
1433
1434error0:
1435        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1436        return error;
1437}
1438
1439STATIC int
1440xfs_btree_lookup_get_block(
1441        struct xfs_btree_cur    *cur,   /* btree cursor */
1442        int                     level,  /* level in the btree */
1443        union xfs_btree_ptr     *pp,    /* ptr to btree block */
1444        struct xfs_btree_block  **blkp) /* return btree block */
1445{
1446        struct xfs_buf          *bp;    /* buffer pointer for btree block */
1447        int                     error = 0;
1448
1449        /* special case the root block if in an inode */
1450        if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1451            (level == cur->bc_nlevels - 1)) {
1452                *blkp = xfs_btree_get_iroot(cur);
1453                return 0;
1454        }
1455
1456        /*
1457         * If the old buffer at this level for the disk address we are
1458         * looking for re-use it.
1459         *
1460         * Otherwise throw it away and get a new one.
1461         */
1462        bp = cur->bc_bufs[level];
1463        if (bp && XFS_BUF_ADDR(bp) == xfs_btree_ptr_to_daddr(cur, pp)) {
1464                *blkp = XFS_BUF_TO_BLOCK(bp);
1465                return 0;
1466        }
1467
1468        error = xfs_btree_read_buf_block(cur, pp, level, 0, blkp, &bp);
1469        if (error)
1470                return error;
1471
1472        xfs_btree_setbuf(cur, level, bp);
1473        return 0;
1474}
1475
1476/*
1477 * Get current search key.  For level 0 we don't actually have a key
1478 * structure so we make one up from the record.  For all other levels
1479 * we just return the right key.
1480 */
1481STATIC union xfs_btree_key *
1482xfs_lookup_get_search_key(
1483        struct xfs_btree_cur    *cur,
1484        int                     level,
1485        int                     keyno,
1486        struct xfs_btree_block  *block,
1487        union xfs_btree_key     *kp)
1488{
1489        if (level == 0) {
1490                cur->bc_ops->init_key_from_rec(kp,
1491                                xfs_btree_rec_addr(cur, keyno, block));
1492                return kp;
1493        }
1494
1495        return xfs_btree_key_addr(cur, keyno, block);
1496}
1497
1498/*
1499 * Lookup the record.  The cursor is made to point to it, based on dir.
1500 * Return 0 if can't find any such record, 1 for success.
1501 */
1502int                                     /* error */
1503xfs_btree_lookup(
1504        struct xfs_btree_cur    *cur,   /* btree cursor */
1505        xfs_lookup_t            dir,    /* <=, ==, or >= */
1506        int                     *stat)  /* success/failure */
1507{
1508        struct xfs_btree_block  *block; /* current btree block */
1509        __int64_t               diff;   /* difference for the current key */
1510        int                     error;  /* error return value */
1511        int                     keyno;  /* current key number */
1512        int                     level;  /* level in the btree */
1513        union xfs_btree_ptr     *pp;    /* ptr to btree block */
1514        union xfs_btree_ptr     ptr;    /* ptr to btree block */
1515
1516        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1517        XFS_BTREE_TRACE_ARGI(cur, dir);
1518
1519        XFS_BTREE_STATS_INC(cur, lookup);
1520
1521        block = NULL;
1522        keyno = 0;
1523
1524        /* initialise start pointer from cursor */
1525        cur->bc_ops->init_ptr_from_cur(cur, &ptr);
1526        pp = &ptr;
1527
1528        /*
1529         * Iterate over each level in the btree, starting at the root.
1530         * For each level above the leaves, find the key we need, based
1531         * on the lookup record, then follow the corresponding block
1532         * pointer down to the next level.
1533         */
1534        for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {
1535                /* Get the block we need to do the lookup on. */
1536                error = xfs_btree_lookup_get_block(cur, level, pp, &block);
1537                if (error)
1538                        goto error0;
1539
1540                if (diff == 0) {
1541                        /*
1542                         * If we already had a key match at a higher level, we
1543                         * know we need to use the first entry in this block.
1544                         */
1545                        keyno = 1;
1546                } else {
1547                        /* Otherwise search this block. Do a binary search. */
1548
1549                        int     high;   /* high entry number */
1550                        int     low;    /* low entry number */
1551
1552                        /* Set low and high entry numbers, 1-based. */
1553                        low = 1;
1554                        high = xfs_btree_get_numrecs(block);
1555                        if (!high) {
1556                                /* Block is empty, must be an empty leaf. */
1557                                ASSERT(level == 0 && cur->bc_nlevels == 1);
1558
1559                                cur->bc_ptrs[0] = dir != XFS_LOOKUP_LE;
1560                                XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1561                                *stat = 0;
1562                                return 0;
1563                        }
1564
1565                        /* Binary search the block. */
1566                        while (low <= high) {
1567                                union xfs_btree_key     key;
1568                                union xfs_btree_key     *kp;
1569
1570                                XFS_BTREE_STATS_INC(cur, compare);
1571
1572                                /* keyno is average of low and high. */
1573                                keyno = (low + high) >> 1;
1574
1575                                /* Get current search key */
1576                                kp = xfs_lookup_get_search_key(cur, level,
1577                                                keyno, block, &key);
1578
1579                                /*
1580                                 * Compute difference to get next direction:
1581                                 *  - less than, move right
1582                                 *  - greater than, move left
1583                                 *  - equal, we're done
1584                                 */
1585                                diff = cur->bc_ops->key_diff(cur, kp);
1586                                if (diff < 0)
1587                                        low = keyno + 1;
1588                                else if (diff > 0)
1589                                        high = keyno - 1;
1590                                else
1591                                        break;
1592                        }
1593                }
1594
1595                /*
1596                 * If there are more levels, set up for the next level
1597                 * by getting the block number and filling in the cursor.
1598                 */
1599                if (level > 0) {
1600                        /*
1601                         * If we moved left, need the previous key number,
1602                         * unless there isn't one.
1603                         */
1604                        if (diff > 0 && --keyno < 1)
1605                                keyno = 1;
1606                        pp = xfs_btree_ptr_addr(cur, keyno, block);
1607
1608#ifdef DEBUG
1609                        error = xfs_btree_check_ptr(cur, pp, 0, level);
1610                        if (error)
1611                                goto error0;
1612#endif
1613                        cur->bc_ptrs[level] = keyno;
1614                }
1615        }
1616
1617        /* Done with the search. See if we need to adjust the results. */
1618        if (dir != XFS_LOOKUP_LE && diff < 0) {
1619                keyno++;
1620                /*
1621                 * If ge search and we went off the end of the block, but it's
1622                 * not the last block, we're in the wrong block.
1623                 */
1624                xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1625                if (dir == XFS_LOOKUP_GE &&
1626                    keyno > xfs_btree_get_numrecs(block) &&
1627                    !xfs_btree_ptr_is_null(cur, &ptr)) {
1628                        int     i;
1629
1630                        cur->bc_ptrs[0] = keyno;
1631                        error = xfs_btree_increment(cur, 0, &i);
1632                        if (error)
1633                                goto error0;
1634                        XFS_WANT_CORRUPTED_RETURN(i == 1);
1635                        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1636                        *stat = 1;
1637                        return 0;
1638                }
1639        } else if (dir == XFS_LOOKUP_LE && diff > 0)
1640                keyno--;
1641        cur->bc_ptrs[0] = keyno;
1642
1643        /* Return if we succeeded or not. */
1644        if (keyno == 0 || keyno > xfs_btree_get_numrecs(block))
1645                *stat = 0;
1646        else if (dir != XFS_LOOKUP_EQ || diff == 0)
1647                *stat = 1;
1648        else
1649                *stat = 0;
1650        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1651        return 0;
1652
1653error0:
1654        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1655        return error;
1656}
1657
1658/*
1659 * Update keys at all levels from here to the root along the cursor's path.
1660 */
1661STATIC int
1662xfs_btree_updkey(
1663        struct xfs_btree_cur    *cur,
1664        union xfs_btree_key     *keyp,
1665        int                     level)
1666{
1667        struct xfs_btree_block  *block;
1668        struct xfs_buf          *bp;
1669        union xfs_btree_key     *kp;
1670        int                     ptr;
1671
1672        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1673        XFS_BTREE_TRACE_ARGIK(cur, level, keyp);
1674
1675        ASSERT(!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) || level >= 1);
1676
1677        /*
1678         * Go up the tree from this level toward the root.
1679         * At each level, update the key value to the value input.
1680         * Stop when we reach a level where the cursor isn't pointing
1681         * at the first entry in the block.
1682         */
1683        for (ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
1684#ifdef DEBUG
1685                int             error;
1686#endif
1687                block = xfs_btree_get_block(cur, level, &bp);
1688#ifdef DEBUG
1689                error = xfs_btree_check_block(cur, block, level, bp);
1690                if (error) {
1691                        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1692                        return error;
1693                }
1694#endif
1695                ptr = cur->bc_ptrs[level];
1696                kp = xfs_btree_key_addr(cur, ptr, block);
1697                xfs_btree_copy_keys(cur, kp, keyp, 1);
1698                xfs_btree_log_keys(cur, bp, ptr, ptr);
1699        }
1700
1701        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1702        return 0;
1703}
1704
1705/*
1706 * Update the record referred to by cur to the value in the
1707 * given record. This either works (return 0) or gets an
1708 * EFSCORRUPTED error.
1709 */
1710int
1711xfs_btree_update(
1712        struct xfs_btree_cur    *cur,
1713        union xfs_btree_rec     *rec)
1714{
1715        struct xfs_btree_block  *block;
1716        struct xfs_buf          *bp;
1717        int                     error;
1718        int                     ptr;
1719        union xfs_btree_rec     *rp;
1720
1721        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1722        XFS_BTREE_TRACE_ARGR(cur, rec);
1723
1724        /* Pick up the current block. */
1725        block = xfs_btree_get_block(cur, 0, &bp);
1726
1727#ifdef DEBUG
1728        error = xfs_btree_check_block(cur, block, 0, bp);
1729        if (error)
1730                goto error0;
1731#endif
1732        /* Get the address of the rec to be updated. */
1733        ptr = cur->bc_ptrs[0];
1734        rp = xfs_btree_rec_addr(cur, ptr, block);
1735
1736        /* Fill in the new contents and log them. */
1737        xfs_btree_copy_recs(cur, rp, rec, 1);
1738        xfs_btree_log_recs(cur, bp, ptr, ptr);
1739
1740        /*
1741         * If we are tracking the last record in the tree and
1742         * we are at the far right edge of the tree, update it.
1743         */
1744        if (xfs_btree_is_lastrec(cur, block, 0)) {
1745                cur->bc_ops->update_lastrec(cur, block, rec,
1746                                            ptr, LASTREC_UPDATE);
1747        }
1748
1749        /* Updating first rec in leaf. Pass new key value up to our parent. */
1750        if (ptr == 1) {
1751                union xfs_btree_key     key;
1752
1753                cur->bc_ops->init_key_from_rec(&key, rec);
1754                error = xfs_btree_updkey(cur, &key, 1);
1755                if (error)
1756                        goto error0;
1757        }
1758
1759        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1760        return 0;
1761
1762error0:
1763        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1764        return error;
1765}
1766
1767/*
1768 * Move 1 record left from cur/level if possible.
1769 * Update cur to reflect the new path.
1770 */
1771STATIC int                                      /* error */
1772xfs_btree_lshift(
1773        struct xfs_btree_cur    *cur,
1774        int                     level,
1775        int                     *stat)          /* success/failure */
1776{
1777        union xfs_btree_key     key;            /* btree key */
1778        struct xfs_buf          *lbp;           /* left buffer pointer */
1779        struct xfs_btree_block  *left;          /* left btree block */
1780        int                     lrecs;          /* left record count */
1781        struct xfs_buf          *rbp;           /* right buffer pointer */
1782        struct xfs_btree_block  *right;         /* right btree block */
1783        int                     rrecs;          /* right record count */
1784        union xfs_btree_ptr     lptr;           /* left btree pointer */
1785        union xfs_btree_key     *rkp = NULL;    /* right btree key */
1786        union xfs_btree_ptr     *rpp = NULL;    /* right address pointer */
1787        union xfs_btree_rec     *rrp = NULL;    /* right record pointer */
1788        int                     error;          /* error return value */
1789
1790        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1791        XFS_BTREE_TRACE_ARGI(cur, level);
1792
1793        if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1794            level == cur->bc_nlevels - 1)
1795                goto out0;
1796
1797        /* Set up variables for this block as "right". */
1798        right = xfs_btree_get_block(cur, level, &rbp);
1799
1800#ifdef DEBUG
1801        error = xfs_btree_check_block(cur, right, level, rbp);
1802        if (error)
1803                goto error0;
1804#endif
1805
1806        /* If we've got no left sibling then we can't shift an entry left. */
1807        xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
1808        if (xfs_btree_ptr_is_null(cur, &lptr))
1809                goto out0;
1810
1811        /*
1812         * If the cursor entry is the one that would be moved, don't
1813         * do it... it's too complicated.
1814         */
1815        if (cur->bc_ptrs[level] <= 1)
1816                goto out0;
1817
1818        /* Set up the left neighbor as "left". */
1819        error = xfs_btree_read_buf_block(cur, &lptr, level, 0, &left, &lbp);
1820        if (error)
1821                goto error0;
1822
1823        /* If it's full, it can't take another entry. */
1824        lrecs = xfs_btree_get_numrecs(left);
1825        if (lrecs == cur->bc_ops->get_maxrecs(cur, level))
1826                goto out0;
1827
1828        rrecs = xfs_btree_get_numrecs(right);
1829
1830        /*
1831         * We add one entry to the left side and remove one for the right side.
1832         * Account for it here, the changes will be updated on disk and logged
1833         * later.
1834         */
1835        lrecs++;
1836        rrecs--;
1837
1838        XFS_BTREE_STATS_INC(cur, lshift);
1839        XFS_BTREE_STATS_ADD(cur, moves, 1);
1840
1841        /*
1842         * If non-leaf, copy a key and a ptr to the left block.
1843         * Log the changes to the left block.
1844         */
1845        if (level > 0) {
1846                /* It's a non-leaf.  Move keys and pointers. */
1847                union xfs_btree_key     *lkp;   /* left btree key */
1848                union xfs_btree_ptr     *lpp;   /* left address pointer */
1849
1850                lkp = xfs_btree_key_addr(cur, lrecs, left);
1851                rkp = xfs_btree_key_addr(cur, 1, right);
1852
1853                lpp = xfs_btree_ptr_addr(cur, lrecs, left);
1854                rpp = xfs_btree_ptr_addr(cur, 1, right);
1855#ifdef DEBUG
1856                error = xfs_btree_check_ptr(cur, rpp, 0, level);
1857                if (error)
1858                        goto error0;
1859#endif
1860                xfs_btree_copy_keys(cur, lkp, rkp, 1);
1861                xfs_btree_copy_ptrs(cur, lpp, rpp, 1);
1862
1863                xfs_btree_log_keys(cur, lbp, lrecs, lrecs);
1864                xfs_btree_log_ptrs(cur, lbp, lrecs, lrecs);
1865
1866                ASSERT(cur->bc_ops->keys_inorder(cur,
1867                        xfs_btree_key_addr(cur, lrecs - 1, left), lkp));
1868        } else {
1869                /* It's a leaf.  Move records.  */
1870                union xfs_btree_rec     *lrp;   /* left record pointer */
1871
1872                lrp = xfs_btree_rec_addr(cur, lrecs, left);
1873                rrp = xfs_btree_rec_addr(cur, 1, right);
1874
1875                xfs_btree_copy_recs(cur, lrp, rrp, 1);
1876                xfs_btree_log_recs(cur, lbp, lrecs, lrecs);
1877
1878                ASSERT(cur->bc_ops->recs_inorder(cur,
1879                        xfs_btree_rec_addr(cur, lrecs - 1, left), lrp));
1880        }
1881
1882        xfs_btree_set_numrecs(left, lrecs);
1883        xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
1884
1885        xfs_btree_set_numrecs(right, rrecs);
1886        xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
1887
1888        /*
1889         * Slide the contents of right down one entry.
1890         */
1891        XFS_BTREE_STATS_ADD(cur, moves, rrecs - 1);
1892        if (level > 0) {
1893                /* It's a nonleaf. operate on keys and ptrs */
1894#ifdef DEBUG
1895                int                     i;              /* loop index */
1896
1897                for (i = 0; i < rrecs; i++) {
1898                        error = xfs_btree_check_ptr(cur, rpp, i + 1, level);
1899                        if (error)
1900                                goto error0;
1901                }
1902#endif
1903                xfs_btree_shift_keys(cur,
1904                                xfs_btree_key_addr(cur, 2, right),
1905                                -1, rrecs);
1906                xfs_btree_shift_ptrs(cur,
1907                                xfs_btree_ptr_addr(cur, 2, right),
1908                                -1, rrecs);
1909
1910                xfs_btree_log_keys(cur, rbp, 1, rrecs);
1911                xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
1912        } else {
1913                /* It's a leaf. operate on records */
1914                xfs_btree_shift_recs(cur,
1915                        xfs_btree_rec_addr(cur, 2, right),
1916                        -1, rrecs);
1917                xfs_btree_log_recs(cur, rbp, 1, rrecs);
1918
1919                /*
1920                 * If it's the first record in the block, we'll need a key
1921                 * structure to pass up to the next level (updkey).
1922                 */
1923                cur->bc_ops->init_key_from_rec(&key,
1924                        xfs_btree_rec_addr(cur, 1, right));
1925                rkp = &key;
1926        }
1927
1928        /* Update the parent key values of right. */
1929        error = xfs_btree_updkey(cur, rkp, level + 1);
1930        if (error)
1931                goto error0;
1932
1933        /* Slide the cursor value left one. */
1934        cur->bc_ptrs[level]--;
1935
1936        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1937        *stat = 1;
1938        return 0;
1939
1940out0:
1941        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
1942        *stat = 0;
1943        return 0;
1944
1945error0:
1946        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
1947        return error;
1948}
1949
1950/*
1951 * Move 1 record right from cur/level if possible.
1952 * Update cur to reflect the new path.
1953 */
1954STATIC int                                      /* error */
1955xfs_btree_rshift(
1956        struct xfs_btree_cur    *cur,
1957        int                     level,
1958        int                     *stat)          /* success/failure */
1959{
1960        union xfs_btree_key     key;            /* btree key */
1961        struct xfs_buf          *lbp;           /* left buffer pointer */
1962        struct xfs_btree_block  *left;          /* left btree block */
1963        struct xfs_buf          *rbp;           /* right buffer pointer */
1964        struct xfs_btree_block  *right;         /* right btree block */
1965        struct xfs_btree_cur    *tcur;          /* temporary btree cursor */
1966        union xfs_btree_ptr     rptr;           /* right block pointer */
1967        union xfs_btree_key     *rkp;           /* right btree key */
1968        int                     rrecs;          /* right record count */
1969        int                     lrecs;          /* left record count */
1970        int                     error;          /* error return value */
1971        int                     i;              /* loop counter */
1972
1973        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
1974        XFS_BTREE_TRACE_ARGI(cur, level);
1975
1976        if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1977            (level == cur->bc_nlevels - 1))
1978                goto out0;
1979
1980        /* Set up variables for this block as "left". */
1981        left = xfs_btree_get_block(cur, level, &lbp);
1982
1983#ifdef DEBUG
1984        error = xfs_btree_check_block(cur, left, level, lbp);
1985        if (error)
1986                goto error0;
1987#endif
1988
1989        /* If we've got no right sibling then we can't shift an entry right. */
1990        xfs_btree_get_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
1991        if (xfs_btree_ptr_is_null(cur, &rptr))
1992                goto out0;
1993
1994        /*
1995         * If the cursor entry is the one that would be moved, don't
1996         * do it... it's too complicated.
1997         */
1998        lrecs = xfs_btree_get_numrecs(left);
1999        if (cur->bc_ptrs[level] >= lrecs)
2000                goto out0;
2001
2002        /* Set up the right neighbor as "right". */
2003        error = xfs_btree_read_buf_block(cur, &rptr, level, 0, &right, &rbp);
2004        if (error)
2005                goto error0;
2006
2007        /* If it's full, it can't take another entry. */
2008        rrecs = xfs_btree_get_numrecs(right);
2009        if (rrecs == cur->bc_ops->get_maxrecs(cur, level))
2010                goto out0;
2011
2012        XFS_BTREE_STATS_INC(cur, rshift);
2013        XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2014
2015        /*
2016         * Make a hole at the start of the right neighbor block, then
2017         * copy the last left block entry to the hole.
2018         */
2019        if (level > 0) {
2020                /* It's a nonleaf. make a hole in the keys and ptrs */
2021                union xfs_btree_key     *lkp;
2022                union xfs_btree_ptr     *lpp;
2023                union xfs_btree_ptr     *rpp;
2024
2025                lkp = xfs_btree_key_addr(cur, lrecs, left);
2026                lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2027                rkp = xfs_btree_key_addr(cur, 1, right);
2028                rpp = xfs_btree_ptr_addr(cur, 1, right);
2029
2030#ifdef DEBUG
2031                for (i = rrecs - 1; i >= 0; i--) {
2032                        error = xfs_btree_check_ptr(cur, rpp, i, level);
2033                        if (error)
2034                                goto error0;
2035                }
2036#endif
2037
2038                xfs_btree_shift_keys(cur, rkp, 1, rrecs);
2039                xfs_btree_shift_ptrs(cur, rpp, 1, rrecs);
2040
2041#ifdef DEBUG
2042                error = xfs_btree_check_ptr(cur, lpp, 0, level);
2043                if (error)
2044                        goto error0;
2045#endif
2046
2047                /* Now put the new data in, and log it. */
2048                xfs_btree_copy_keys(cur, rkp, lkp, 1);
2049                xfs_btree_copy_ptrs(cur, rpp, lpp, 1);
2050
2051                xfs_btree_log_keys(cur, rbp, 1, rrecs + 1);
2052                xfs_btree_log_ptrs(cur, rbp, 1, rrecs + 1);
2053
2054                ASSERT(cur->bc_ops->keys_inorder(cur, rkp,
2055                        xfs_btree_key_addr(cur, 2, right)));
2056        } else {
2057                /* It's a leaf. make a hole in the records */
2058                union xfs_btree_rec     *lrp;
2059                union xfs_btree_rec     *rrp;
2060
2061                lrp = xfs_btree_rec_addr(cur, lrecs, left);
2062                rrp = xfs_btree_rec_addr(cur, 1, right);
2063
2064                xfs_btree_shift_recs(cur, rrp, 1, rrecs);
2065
2066                /* Now put the new data in, and log it. */
2067                xfs_btree_copy_recs(cur, rrp, lrp, 1);
2068                xfs_btree_log_recs(cur, rbp, 1, rrecs + 1);
2069
2070                cur->bc_ops->init_key_from_rec(&key, rrp);
2071                rkp = &key;
2072
2073                ASSERT(cur->bc_ops->recs_inorder(cur, rrp,
2074                        xfs_btree_rec_addr(cur, 2, right)));
2075        }
2076
2077        /*
2078         * Decrement and log left's numrecs, bump and log right's numrecs.
2079         */
2080        xfs_btree_set_numrecs(left, --lrecs);
2081        xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2082
2083        xfs_btree_set_numrecs(right, ++rrecs);
2084        xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2085
2086        /*
2087         * Using a temporary cursor, update the parent key values of the
2088         * block on the right.
2089         */
2090        error = xfs_btree_dup_cursor(cur, &tcur);
2091        if (error)
2092                goto error0;
2093        i = xfs_btree_lastrec(tcur, level);
2094        XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
2095
2096        error = xfs_btree_increment(tcur, level, &i);
2097        if (error)
2098                goto error1;
2099
2100        error = xfs_btree_updkey(tcur, rkp, level + 1);
2101        if (error)
2102                goto error1;
2103
2104        xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2105
2106        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2107        *stat = 1;
2108        return 0;
2109
2110out0:
2111        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2112        *stat = 0;
2113        return 0;
2114
2115error0:
2116        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2117        return error;
2118
2119error1:
2120        XFS_BTREE_TRACE_CURSOR(tcur, XBT_ERROR);
2121        xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2122        return error;
2123}
2124
2125/*
2126 * Split cur/level block in half.
2127 * Return new block number and the key to its first
2128 * record (to be inserted into parent).
2129 */
2130STATIC int                                      /* error */
2131xfs_btree_split(
2132        struct xfs_btree_cur    *cur,
2133        int                     level,
2134        union xfs_btree_ptr     *ptrp,
2135        union xfs_btree_key     *key,
2136        struct xfs_btree_cur    **curp,
2137        int                     *stat)          /* success/failure */
2138{
2139        union xfs_btree_ptr     lptr;           /* left sibling block ptr */
2140        struct xfs_buf          *lbp;           /* left buffer pointer */
2141        struct xfs_btree_block  *left;          /* left btree block */
2142        union xfs_btree_ptr     rptr;           /* right sibling block ptr */
2143        struct xfs_buf          *rbp;           /* right buffer pointer */
2144        struct xfs_btree_block  *right;         /* right btree block */
2145        union xfs_btree_ptr     rrptr;          /* right-right sibling ptr */
2146        struct xfs_buf          *rrbp;          /* right-right buffer pointer */
2147        struct xfs_btree_block  *rrblock;       /* right-right btree block */
2148        int                     lrecs;
2149        int                     rrecs;
2150        int                     src_index;
2151        int                     error;          /* error return value */
2152#ifdef DEBUG
2153        int                     i;
2154#endif
2155
2156        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2157        XFS_BTREE_TRACE_ARGIPK(cur, level, *ptrp, key);
2158
2159        XFS_BTREE_STATS_INC(cur, split);
2160
2161        /* Set up left block (current one). */
2162        left = xfs_btree_get_block(cur, level, &lbp);
2163
2164#ifdef DEBUG
2165        error = xfs_btree_check_block(cur, left, level, lbp);
2166        if (error)
2167                goto error0;
2168#endif
2169
2170        xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2171
2172        /* Allocate the new block. If we can't do it, we're toast. Give up. */
2173        error = cur->bc_ops->alloc_block(cur, &lptr, &rptr, 1, stat);
2174        if (error)
2175                goto error0;
2176        if (*stat == 0)
2177                goto out0;
2178        XFS_BTREE_STATS_INC(cur, alloc);
2179
2180        /* Set up the new block as "right". */
2181        error = xfs_btree_get_buf_block(cur, &rptr, 0, &right, &rbp);
2182        if (error)
2183                goto error0;
2184
2185        /* Fill in the btree header for the new right block. */
2186        xfs_btree_init_block(cur, xfs_btree_get_level(left), 0, right);
2187
2188        /*
2189         * Split the entries between the old and the new block evenly.
2190         * Make sure that if there's an odd number of entries now, that
2191         * each new block will have the same number of entries.
2192         */
2193        lrecs = xfs_btree_get_numrecs(left);
2194        rrecs = lrecs / 2;
2195        if ((lrecs & 1) && cur->bc_ptrs[level] <= rrecs + 1)
2196                rrecs++;
2197        src_index = (lrecs - rrecs + 1);
2198
2199        XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2200
2201        /*
2202         * Copy btree block entries from the left block over to the
2203         * new block, the right. Update the right block and log the
2204         * changes.
2205         */
2206        if (level > 0) {
2207                /* It's a non-leaf.  Move keys and pointers. */
2208                union xfs_btree_key     *lkp;   /* left btree key */
2209                union xfs_btree_ptr     *lpp;   /* left address pointer */
2210                union xfs_btree_key     *rkp;   /* right btree key */
2211                union xfs_btree_ptr     *rpp;   /* right address pointer */
2212
2213                lkp = xfs_btree_key_addr(cur, src_index, left);
2214                lpp = xfs_btree_ptr_addr(cur, src_index, left);
2215                rkp = xfs_btree_key_addr(cur, 1, right);
2216                rpp = xfs_btree_ptr_addr(cur, 1, right);
2217
2218#ifdef DEBUG
2219                for (i = src_index; i < rrecs; i++) {
2220                        error = xfs_btree_check_ptr(cur, lpp, i, level);
2221                        if (error)
2222                                goto error0;
2223                }
2224#endif
2225
2226                xfs_btree_copy_keys(cur, rkp, lkp, rrecs);
2227                xfs_btree_copy_ptrs(cur, rpp, lpp, rrecs);
2228
2229                xfs_btree_log_keys(cur, rbp, 1, rrecs);
2230                xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2231
2232                /* Grab the keys to the entries moved to the right block */
2233                xfs_btree_copy_keys(cur, key, rkp, 1);
2234        } else {
2235                /* It's a leaf.  Move records.  */
2236                union xfs_btree_rec     *lrp;   /* left record pointer */
2237                union xfs_btree_rec     *rrp;   /* right record pointer */
2238
2239                lrp = xfs_btree_rec_addr(cur, src_index, left);
2240                rrp = xfs_btree_rec_addr(cur, 1, right);
2241
2242                xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
2243                xfs_btree_log_recs(cur, rbp, 1, rrecs);
2244
2245                cur->bc_ops->init_key_from_rec(key,
2246                        xfs_btree_rec_addr(cur, 1, right));
2247        }
2248
2249
2250        /*
2251         * Find the left block number by looking in the buffer.
2252         * Adjust numrecs, sibling pointers.
2253         */
2254        xfs_btree_get_sibling(cur, left, &rrptr, XFS_BB_RIGHTSIB);
2255        xfs_btree_set_sibling(cur, right, &rrptr, XFS_BB_RIGHTSIB);
2256        xfs_btree_set_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2257        xfs_btree_set_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2258
2259        lrecs -= rrecs;
2260        xfs_btree_set_numrecs(left, lrecs);
2261        xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
2262
2263        xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
2264        xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
2265
2266        /*
2267         * If there's a block to the new block's right, make that block
2268         * point back to right instead of to left.
2269         */
2270        if (!xfs_btree_ptr_is_null(cur, &rrptr)) {
2271                error = xfs_btree_read_buf_block(cur, &rrptr, level,
2272                                                        0, &rrblock, &rrbp);
2273                if (error)
2274                        goto error0;
2275                xfs_btree_set_sibling(cur, rrblock, &rptr, XFS_BB_LEFTSIB);
2276                xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
2277        }
2278        /*
2279         * If the cursor is really in the right block, move it there.
2280         * If it's just pointing past the last entry in left, then we'll
2281         * insert there, so don't change anything in that case.
2282         */
2283        if (cur->bc_ptrs[level] > lrecs + 1) {
2284                xfs_btree_setbuf(cur, level, rbp);
2285                cur->bc_ptrs[level] -= lrecs;
2286        }
2287        /*
2288         * If there are more levels, we'll need another cursor which refers
2289         * the right block, no matter where this cursor was.
2290         */
2291        if (level + 1 < cur->bc_nlevels) {
2292                error = xfs_btree_dup_cursor(cur, curp);
2293                if (error)
2294                        goto error0;
2295                (*curp)->bc_ptrs[level + 1]++;
2296        }
2297        *ptrp = rptr;
2298        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2299        *stat = 1;
2300        return 0;
2301out0:
2302        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2303        *stat = 0;
2304        return 0;
2305
2306error0:
2307        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2308        return error;
2309}
2310
2311/*
2312 * Copy the old inode root contents into a real block and make the
2313 * broot point to it.
2314 */
2315int                                             /* error */
2316xfs_btree_new_iroot(
2317        struct xfs_btree_cur    *cur,           /* btree cursor */
2318        int                     *logflags,      /* logging flags for inode */
2319        int                     *stat)          /* return status - 0 fail */
2320{
2321        struct xfs_buf          *cbp;           /* buffer for cblock */
2322        struct xfs_btree_block  *block;         /* btree block */
2323        struct xfs_btree_block  *cblock;        /* child btree block */
2324        union xfs_btree_key     *ckp;           /* child key pointer */
2325        union xfs_btree_ptr     *cpp;           /* child ptr pointer */
2326        union xfs_btree_key     *kp;            /* pointer to btree key */
2327        union xfs_btree_ptr     *pp;            /* pointer to block addr */
2328        union xfs_btree_ptr     nptr;           /* new block addr */
2329        int                     level;          /* btree level */
2330        int                     error;          /* error return code */
2331#ifdef DEBUG
2332        int                     i;              /* loop counter */
2333#endif
2334
2335        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2336        XFS_BTREE_STATS_INC(cur, newroot);
2337
2338        ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
2339
2340        level = cur->bc_nlevels - 1;
2341
2342        block = xfs_btree_get_iroot(cur);
2343        pp = xfs_btree_ptr_addr(cur, 1, block);
2344
2345        /* Allocate the new block. If we can't do it, we're toast. Give up. */
2346        error = cur->bc_ops->alloc_block(cur, pp, &nptr, 1, stat);
2347        if (error)
2348                goto error0;
2349        if (*stat == 0) {
2350                XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2351                return 0;
2352        }
2353        XFS_BTREE_STATS_INC(cur, alloc);
2354
2355        /* Copy the root into a real block. */
2356        error = xfs_btree_get_buf_block(cur, &nptr, 0, &cblock, &cbp);
2357        if (error)
2358                goto error0;
2359
2360        memcpy(cblock, block, xfs_btree_block_len(cur));
2361
2362        be16_add_cpu(&block->bb_level, 1);
2363        xfs_btree_set_numrecs(block, 1);
2364        cur->bc_nlevels++;
2365        cur->bc_ptrs[level + 1] = 1;
2366
2367        kp = xfs_btree_key_addr(cur, 1, block);
2368        ckp = xfs_btree_key_addr(cur, 1, cblock);
2369        xfs_btree_copy_keys(cur, ckp, kp, xfs_btree_get_numrecs(cblock));
2370
2371        cpp = xfs_btree_ptr_addr(cur, 1, cblock);
2372#ifdef DEBUG
2373        for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
2374                error = xfs_btree_check_ptr(cur, pp, i, level);
2375                if (error)
2376                        goto error0;
2377        }
2378#endif
2379        xfs_btree_copy_ptrs(cur, cpp, pp, xfs_btree_get_numrecs(cblock));
2380
2381#ifdef DEBUG
2382        error = xfs_btree_check_ptr(cur, &nptr, 0, level);
2383        if (error)
2384                goto error0;
2385#endif
2386        xfs_btree_copy_ptrs(cur, pp, &nptr, 1);
2387
2388        xfs_iroot_realloc(cur->bc_private.b.ip,
2389                          1 - xfs_btree_get_numrecs(cblock),
2390                          cur->bc_private.b.whichfork);
2391
2392        xfs_btree_setbuf(cur, level, cbp);
2393
2394        /*
2395         * Do all this logging at the end so that
2396         * the root is at the right level.
2397         */
2398        xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
2399        xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
2400        xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
2401
2402        *logflags |=
2403                XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_private.b.whichfork);
2404        *stat = 1;
2405        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2406        return 0;
2407error0:
2408        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2409        return error;
2410}
2411
2412/*
2413 * Allocate a new root block, fill it in.
2414 */
2415STATIC int                              /* error */
2416xfs_btree_new_root(
2417        struct xfs_btree_cur    *cur,   /* btree cursor */
2418        int                     *stat)  /* success/failure */
2419{
2420        struct xfs_btree_block  *block; /* one half of the old root block */
2421        struct xfs_buf          *bp;    /* buffer containing block */
2422        int                     error;  /* error return value */
2423        struct xfs_buf          *lbp;   /* left buffer pointer */
2424        struct xfs_btree_block  *left;  /* left btree block */
2425        struct xfs_buf          *nbp;   /* new (root) buffer */
2426        struct xfs_btree_block  *new;   /* new (root) btree block */
2427        int                     nptr;   /* new value for key index, 1 or 2 */
2428        struct xfs_buf          *rbp;   /* right buffer pointer */
2429        struct xfs_btree_block  *right; /* right btree block */
2430        union xfs_btree_ptr     rptr;
2431        union xfs_btree_ptr     lptr;
2432
2433        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2434        XFS_BTREE_STATS_INC(cur, newroot);
2435
2436        /* initialise our start point from the cursor */
2437        cur->bc_ops->init_ptr_from_cur(cur, &rptr);
2438
2439        /* Allocate the new block. If we can't do it, we're toast. Give up. */
2440        error = cur->bc_ops->alloc_block(cur, &rptr, &lptr, 1, stat);
2441        if (error)
2442                goto error0;
2443        if (*stat == 0)
2444                goto out0;
2445        XFS_BTREE_STATS_INC(cur, alloc);
2446
2447        /* Set up the new block. */
2448        error = xfs_btree_get_buf_block(cur, &lptr, 0, &new, &nbp);
2449        if (error)
2450                goto error0;
2451
2452        /* Set the root in the holding structure  increasing the level by 1. */
2453        cur->bc_ops->set_root(cur, &lptr, 1);
2454
2455        /*
2456         * At the previous root level there are now two blocks: the old root,
2457         * and the new block generated when it was split.  We don't know which
2458         * one the cursor is pointing at, so we set up variables "left" and
2459         * "right" for each case.
2460         */
2461        block = xfs_btree_get_block(cur, cur->bc_nlevels - 1, &bp);
2462
2463#ifdef DEBUG
2464        error = xfs_btree_check_block(cur, block, cur->bc_nlevels - 1, bp);
2465        if (error)
2466                goto error0;
2467#endif
2468
2469        xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
2470        if (!xfs_btree_ptr_is_null(cur, &rptr)) {
2471                /* Our block is left, pick up the right block. */
2472                lbp = bp;
2473                xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2474                left = block;
2475                error = xfs_btree_read_buf_block(cur, &rptr,
2476                                        cur->bc_nlevels - 1, 0, &right, &rbp);
2477                if (error)
2478                        goto error0;
2479                bp = rbp;
2480                nptr = 1;
2481        } else {
2482                /* Our block is right, pick up the left block. */
2483                rbp = bp;
2484                xfs_btree_buf_to_ptr(cur, rbp, &rptr);
2485                right = block;
2486                xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2487                error = xfs_btree_read_buf_block(cur, &lptr,
2488                                        cur->bc_nlevels - 1, 0, &left, &lbp);
2489                if (error)
2490                        goto error0;
2491                bp = lbp;
2492                nptr = 2;
2493        }
2494        /* Fill in the new block's btree header and log it. */
2495        xfs_btree_init_block(cur, cur->bc_nlevels, 2, new);
2496        xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
2497        ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
2498                        !xfs_btree_ptr_is_null(cur, &rptr));
2499
2500        /* Fill in the key data in the new root. */
2501        if (xfs_btree_get_level(left) > 0) {
2502                xfs_btree_copy_keys(cur,
2503                                xfs_btree_key_addr(cur, 1, new),
2504                                xfs_btree_key_addr(cur, 1, left), 1);
2505                xfs_btree_copy_keys(cur,
2506                                xfs_btree_key_addr(cur, 2, new),
2507                                xfs_btree_key_addr(cur, 1, right), 1);
2508        } else {
2509                cur->bc_ops->init_key_from_rec(
2510                                xfs_btree_key_addr(cur, 1, new),
2511                                xfs_btree_rec_addr(cur, 1, left));
2512                cur->bc_ops->init_key_from_rec(
2513                                xfs_btree_key_addr(cur, 2, new),
2514                                xfs_btree_rec_addr(cur, 1, right));
2515        }
2516        xfs_btree_log_keys(cur, nbp, 1, 2);
2517
2518        /* Fill in the pointer data in the new root. */
2519        xfs_btree_copy_ptrs(cur,
2520                xfs_btree_ptr_addr(cur, 1, new), &lptr, 1);
2521        xfs_btree_copy_ptrs(cur,
2522                xfs_btree_ptr_addr(cur, 2, new), &rptr, 1);
2523        xfs_btree_log_ptrs(cur, nbp, 1, 2);
2524
2525        /* Fix up the cursor. */
2526        xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
2527        cur->bc_ptrs[cur->bc_nlevels] = nptr;
2528        cur->bc_nlevels++;
2529        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2530        *stat = 1;
2531        return 0;
2532error0:
2533        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2534        return error;
2535out0:
2536        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2537        *stat = 0;
2538        return 0;
2539}
2540
2541STATIC int
2542xfs_btree_make_block_unfull(
2543        struct xfs_btree_cur    *cur,   /* btree cursor */
2544        int                     level,  /* btree level */
2545        int                     numrecs,/* # of recs in block */
2546        int                     *oindex,/* old tree index */
2547        int                     *index, /* new tree index */
2548        union xfs_btree_ptr     *nptr,  /* new btree ptr */
2549        struct xfs_btree_cur    **ncur, /* new btree cursor */
2550        union xfs_btree_rec     *nrec,  /* new record */
2551        int                     *stat)
2552{
2553        union xfs_btree_key     key;    /* new btree key value */
2554        int                     error = 0;
2555
2556        if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2557            level == cur->bc_nlevels - 1) {
2558                struct xfs_inode *ip = cur->bc_private.b.ip;
2559
2560                if (numrecs < cur->bc_ops->get_dmaxrecs(cur, level)) {
2561                        /* A root block that can be made bigger. */
2562
2563                        xfs_iroot_realloc(ip, 1, cur->bc_private.b.whichfork);
2564                } else {
2565                        /* A root block that needs replacing */
2566                        int     logflags = 0;
2567
2568                        error = xfs_btree_new_iroot(cur, &logflags, stat);
2569                        if (error || *stat == 0)
2570                                return error;
2571
2572                        xfs_trans_log_inode(cur->bc_tp, ip, logflags);
2573                }
2574
2575                return 0;
2576        }
2577
2578        /* First, try shifting an entry to the right neighbor. */
2579        error = xfs_btree_rshift(cur, level, stat);
2580        if (error || *stat)
2581                return error;
2582
2583        /* Next, try shifting an entry to the left neighbor. */
2584        error = xfs_btree_lshift(cur, level, stat);
2585        if (error)
2586                return error;
2587
2588        if (*stat) {
2589                *oindex = *index = cur->bc_ptrs[level];
2590                return 0;
2591        }
2592
2593        /*
2594         * Next, try splitting the current block in half.
2595         *
2596         * If this works we have to re-set our variables because we
2597         * could be in a different block now.
2598         */
2599        error = xfs_btree_split(cur, level, nptr, &key, ncur, stat);
2600        if (error || *stat == 0)
2601                return error;
2602
2603
2604        *index = cur->bc_ptrs[level];
2605        cur->bc_ops->init_rec_from_key(&key, nrec);
2606        return 0;
2607}
2608
2609/*
2610 * Insert one record/level.  Return information to the caller
2611 * allowing the next level up to proceed if necessary.
2612 */
2613STATIC int
2614xfs_btree_insrec(
2615        struct xfs_btree_cur    *cur,   /* btree cursor */
2616        int                     level,  /* level to insert record at */
2617        union xfs_btree_ptr     *ptrp,  /* i/o: block number inserted */
2618        union xfs_btree_rec     *recp,  /* i/o: record data inserted */
2619        struct xfs_btree_cur    **curp, /* output: new cursor replacing cur */
2620        int                     *stat)  /* success/failure */
2621{
2622        struct xfs_btree_block  *block; /* btree block */
2623        struct xfs_buf          *bp;    /* buffer for block */
2624        union xfs_btree_key     key;    /* btree key */
2625        union xfs_btree_ptr     nptr;   /* new block ptr */
2626        struct xfs_btree_cur    *ncur;  /* new btree cursor */
2627        union xfs_btree_rec     nrec;   /* new record count */
2628        int                     optr;   /* old key/record index */
2629        int                     ptr;    /* key/record index */
2630        int                     numrecs;/* number of records */
2631        int                     error;  /* error return value */
2632#ifdef DEBUG
2633        int                     i;
2634#endif
2635
2636        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2637        XFS_BTREE_TRACE_ARGIPR(cur, level, *ptrp, recp);
2638
2639        ncur = NULL;
2640
2641        /*
2642         * If we have an external root pointer, and we've made it to the
2643         * root level, allocate a new root block and we're done.
2644         */
2645        if (!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2646            (level >= cur->bc_nlevels)) {
2647                error = xfs_btree_new_root(cur, stat);
2648                xfs_btree_set_ptr_null(cur, ptrp);
2649
2650                XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2651                return error;
2652        }
2653
2654        /* If we're off the left edge, return failure. */
2655        ptr = cur->bc_ptrs[level];
2656        if (ptr == 0) {
2657                XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2658                *stat = 0;
2659                return 0;
2660        }
2661
2662        /* Make a key out of the record data to be inserted, and save it. */
2663        cur->bc_ops->init_key_from_rec(&key, recp);
2664
2665        optr = ptr;
2666
2667        XFS_BTREE_STATS_INC(cur, insrec);
2668
2669        /* Get pointers to the btree buffer and block. */
2670        block = xfs_btree_get_block(cur, level, &bp);
2671        numrecs = xfs_btree_get_numrecs(block);
2672
2673#ifdef DEBUG
2674        error = xfs_btree_check_block(cur, block, level, bp);
2675        if (error)
2676                goto error0;
2677
2678        /* Check that the new entry is being inserted in the right place. */
2679        if (ptr <= numrecs) {
2680                if (level == 0) {
2681                        ASSERT(cur->bc_ops->recs_inorder(cur, recp,
2682                                xfs_btree_rec_addr(cur, ptr, block)));
2683                } else {
2684                        ASSERT(cur->bc_ops->keys_inorder(cur, &key,
2685                                xfs_btree_key_addr(cur, ptr, block)));
2686                }
2687        }
2688#endif
2689
2690        /*
2691         * If the block is full, we can't insert the new entry until we
2692         * make the block un-full.
2693         */
2694        xfs_btree_set_ptr_null(cur, &nptr);
2695        if (numrecs == cur->bc_ops->get_maxrecs(cur, level)) {
2696                error = xfs_btree_make_block_unfull(cur, level, numrecs,
2697                                        &optr, &ptr, &nptr, &ncur, &nrec, stat);
2698                if (error || *stat == 0)
2699                        goto error0;
2700        }
2701
2702        /*
2703         * The current block may have changed if the block was
2704         * previously full and we have just made space in it.
2705         */
2706        block = xfs_btree_get_block(cur, level, &bp);
2707        numrecs = xfs_btree_get_numrecs(block);
2708
2709#ifdef DEBUG
2710        error = xfs_btree_check_block(cur, block, level, bp);
2711        if (error)
2712                return error;
2713#endif
2714
2715        /*
2716         * At this point we know there's room for our new entry in the block
2717         * we're pointing at.
2718         */
2719        XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr + 1);
2720
2721        if (level > 0) {
2722                /* It's a nonleaf. make a hole in the keys and ptrs */
2723                union xfs_btree_key     *kp;
2724                union xfs_btree_ptr     *pp;
2725
2726                kp = xfs_btree_key_addr(cur, ptr, block);
2727                pp = xfs_btree_ptr_addr(cur, ptr, block);
2728
2729#ifdef DEBUG
2730                for (i = numrecs - ptr; i >= 0; i--) {
2731                        error = xfs_btree_check_ptr(cur, pp, i, level);
2732                        if (error)
2733                                return error;
2734                }
2735#endif
2736
2737                xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1);
2738                xfs_btree_shift_ptrs(cur, pp, 1, numrecs - ptr + 1);
2739
2740#ifdef DEBUG
2741                error = xfs_btree_check_ptr(cur, ptrp, 0, level);
2742                if (error)
2743                        goto error0;
2744#endif
2745
2746                /* Now put the new data in, bump numrecs and log it. */
2747                xfs_btree_copy_keys(cur, kp, &key, 1);
2748                xfs_btree_copy_ptrs(cur, pp, ptrp, 1);
2749                numrecs++;
2750                xfs_btree_set_numrecs(block, numrecs);
2751                xfs_btree_log_ptrs(cur, bp, ptr, numrecs);
2752                xfs_btree_log_keys(cur, bp, ptr, numrecs);
2753#ifdef DEBUG
2754                if (ptr < numrecs) {
2755                        ASSERT(cur->bc_ops->keys_inorder(cur, kp,
2756                                xfs_btree_key_addr(cur, ptr + 1, block)));
2757                }
2758#endif
2759        } else {
2760                /* It's a leaf. make a hole in the records */
2761                union xfs_btree_rec             *rp;
2762
2763                rp = xfs_btree_rec_addr(cur, ptr, block);
2764
2765                xfs_btree_shift_recs(cur, rp, 1, numrecs - ptr + 1);
2766
2767                /* Now put the new data in, bump numrecs and log it. */
2768                xfs_btree_copy_recs(cur, rp, recp, 1);
2769                xfs_btree_set_numrecs(block, ++numrecs);
2770                xfs_btree_log_recs(cur, bp, ptr, numrecs);
2771#ifdef DEBUG
2772                if (ptr < numrecs) {
2773                        ASSERT(cur->bc_ops->recs_inorder(cur, rp,
2774                                xfs_btree_rec_addr(cur, ptr + 1, block)));
2775                }
2776#endif
2777        }
2778
2779        /* Log the new number of records in the btree header. */
2780        xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
2781
2782        /* If we inserted at the start of a block, update the parents' keys. */
2783        if (optr == 1) {
2784                error = xfs_btree_updkey(cur, &key, level + 1);
2785                if (error)
2786                        goto error0;
2787        }
2788
2789        /*
2790         * If we are tracking the last record in the tree and
2791         * we are at the far right edge of the tree, update it.
2792         */
2793        if (xfs_btree_is_lastrec(cur, block, level)) {
2794                cur->bc_ops->update_lastrec(cur, block, recp,
2795                                            ptr, LASTREC_INSREC);
2796        }
2797
2798        /*
2799         * Return the new block number, if any.
2800         * If there is one, give back a record value and a cursor too.
2801         */
2802        *ptrp = nptr;
2803        if (!xfs_btree_ptr_is_null(cur, &nptr)) {
2804                *recp = nrec;
2805                *curp = ncur;
2806        }
2807
2808        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2809        *stat = 1;
2810        return 0;
2811
2812error0:
2813        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2814        return error;
2815}
2816
2817/*
2818 * Insert the record at the point referenced by cur.
2819 *
2820 * A multi-level split of the tree on insert will invalidate the original
2821 * cursor.  All callers of this function should assume that the cursor is
2822 * no longer valid and revalidate it.
2823 */
2824int
2825xfs_btree_insert(
2826        struct xfs_btree_cur    *cur,
2827        int                     *stat)
2828{
2829        int                     error;  /* error return value */
2830        int                     i;      /* result value, 0 for failure */
2831        int                     level;  /* current level number in btree */
2832        union xfs_btree_ptr     nptr;   /* new block number (split result) */
2833        struct xfs_btree_cur    *ncur;  /* new cursor (split result) */
2834        struct xfs_btree_cur    *pcur;  /* previous level's cursor */
2835        union xfs_btree_rec     rec;    /* record to insert */
2836
2837        level = 0;
2838        ncur = NULL;
2839        pcur = cur;
2840
2841        xfs_btree_set_ptr_null(cur, &nptr);
2842        cur->bc_ops->init_rec_from_cur(cur, &rec);
2843
2844        /*
2845         * Loop going up the tree, starting at the leaf level.
2846         * Stop when we don't get a split block, that must mean that
2847         * the insert is finished with this level.
2848         */
2849        do {
2850                /*
2851                 * Insert nrec/nptr into this level of the tree.
2852                 * Note if we fail, nptr will be null.
2853                 */
2854                error = xfs_btree_insrec(pcur, level, &nptr, &rec, &ncur, &i);
2855                if (error) {
2856                        if (pcur != cur)
2857                                xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
2858                        goto error0;
2859                }
2860
2861                XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
2862                level++;
2863
2864                /*
2865                 * See if the cursor we just used is trash.
2866                 * Can't trash the caller's cursor, but otherwise we should
2867                 * if ncur is a new cursor or we're about to be done.
2868                 */
2869                if (pcur != cur &&
2870                    (ncur || xfs_btree_ptr_is_null(cur, &nptr))) {
2871                        /* Save the state from the cursor before we trash it */
2872                        if (cur->bc_ops->update_cursor)
2873                                cur->bc_ops->update_cursor(pcur, cur);
2874                        cur->bc_nlevels = pcur->bc_nlevels;
2875                        xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
2876                }
2877                /* If we got a new cursor, switch to it. */
2878                if (ncur) {
2879                        pcur = ncur;
2880                        ncur = NULL;
2881                }
2882        } while (!xfs_btree_ptr_is_null(cur, &nptr));
2883
2884        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
2885        *stat = i;
2886        return 0;
2887error0:
2888        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2889        return error;
2890}
2891
2892/*
2893 * Try to merge a non-leaf block back into the inode root.
2894 *
2895 * Note: the killroot names comes from the fact that we're effectively
2896 * killing the old root block.  But because we can't just delete the
2897 * inode we have to copy the single block it was pointing to into the
2898 * inode.
2899 */
2900STATIC int
2901xfs_btree_kill_iroot(
2902        struct xfs_btree_cur    *cur)
2903{
2904        int                     whichfork = cur->bc_private.b.whichfork;
2905        struct xfs_inode        *ip = cur->bc_private.b.ip;
2906        struct xfs_ifork        *ifp = XFS_IFORK_PTR(ip, whichfork);
2907        struct xfs_btree_block  *block;
2908        struct xfs_btree_block  *cblock;
2909        union xfs_btree_key     *kp;
2910        union xfs_btree_key     *ckp;
2911        union xfs_btree_ptr     *pp;
2912        union xfs_btree_ptr     *cpp;
2913        struct xfs_buf          *cbp;
2914        int                     level;
2915        int                     index;
2916        int                     numrecs;
2917#ifdef DEBUG
2918        union xfs_btree_ptr     ptr;
2919        int                     i;
2920#endif
2921
2922        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
2923
2924        ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
2925        ASSERT(cur->bc_nlevels > 1);
2926
2927        /*
2928         * Don't deal with the root block needs to be a leaf case.
2929         * We're just going to turn the thing back into extents anyway.
2930         */
2931        level = cur->bc_nlevels - 1;
2932        if (level == 1)
2933                goto out0;
2934
2935        /*
2936         * Give up if the root has multiple children.
2937         */
2938        block = xfs_btree_get_iroot(cur);
2939        if (xfs_btree_get_numrecs(block) != 1)
2940                goto out0;
2941
2942        cblock = xfs_btree_get_block(cur, level - 1, &cbp);
2943        numrecs = xfs_btree_get_numrecs(cblock);
2944
2945        /*
2946         * Only do this if the next level will fit.
2947         * Then the data must be copied up to the inode,
2948         * instead of freeing the root you free the next level.
2949         */
2950        if (numrecs > cur->bc_ops->get_dmaxrecs(cur, level))
2951                goto out0;
2952
2953        XFS_BTREE_STATS_INC(cur, killroot);
2954
2955#ifdef DEBUG
2956        xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
2957        ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
2958        xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
2959        ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
2960#endif
2961
2962        index = numrecs - cur->bc_ops->get_maxrecs(cur, level);
2963        if (index) {
2964                xfs_iroot_realloc(cur->bc_private.b.ip, index,
2965                                  cur->bc_private.b.whichfork);
2966                block = ifp->if_broot;
2967        }
2968
2969        be16_add_cpu(&block->bb_numrecs, index);
2970        ASSERT(block->bb_numrecs == cblock->bb_numrecs);
2971
2972        kp = xfs_btree_key_addr(cur, 1, block);
2973        ckp = xfs_btree_key_addr(cur, 1, cblock);
2974        xfs_btree_copy_keys(cur, kp, ckp, numrecs);
2975
2976        pp = xfs_btree_ptr_addr(cur, 1, block);
2977        cpp = xfs_btree_ptr_addr(cur, 1, cblock);
2978#ifdef DEBUG
2979        for (i = 0; i < numrecs; i++) {
2980                int             error;
2981
2982                error = xfs_btree_check_ptr(cur, cpp, i, level - 1);
2983                if (error) {
2984                        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
2985                        return error;
2986                }
2987        }
2988#endif
2989        xfs_btree_copy_ptrs(cur, pp, cpp, numrecs);
2990
2991        cur->bc_ops->free_block(cur, cbp);
2992        XFS_BTREE_STATS_INC(cur, free);
2993
2994        cur->bc_bufs[level - 1] = NULL;
2995        be16_add_cpu(&block->bb_level, -1);
2996        xfs_trans_log_inode(cur->bc_tp, ip,
2997                XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_private.b.whichfork));
2998        cur->bc_nlevels--;
2999out0:
3000        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3001        return 0;
3002}
3003
3004/*
3005 * Kill the current root node, and replace it with it's only child node.
3006 */
3007STATIC int
3008xfs_btree_kill_root(
3009        struct xfs_btree_cur    *cur,
3010        struct xfs_buf          *bp,
3011        int                     level,
3012        union xfs_btree_ptr     *newroot)
3013{
3014        int                     error;
3015
3016        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
3017        XFS_BTREE_STATS_INC(cur, killroot);
3018
3019        /*
3020         * Update the root pointer, decreasing the level by 1 and then
3021         * free the old root.
3022         */
3023        cur->bc_ops->set_root(cur, newroot, -1);
3024
3025        error = cur->bc_ops->free_block(cur, bp);
3026        if (error) {
3027                XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
3028                return error;
3029        }
3030
3031        XFS_BTREE_STATS_INC(cur, free);
3032
3033        cur->bc_bufs[level] = NULL;
3034        cur->bc_ra[level] = 0;
3035        cur->bc_nlevels--;
3036
3037        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3038        return 0;
3039}
3040
3041STATIC int
3042xfs_btree_dec_cursor(
3043        struct xfs_btree_cur    *cur,
3044        int                     level,
3045        int                     *stat)
3046{
3047        int                     error;
3048        int                     i;
3049
3050        if (level > 0) {
3051                error = xfs_btree_decrement(cur, level, &i);
3052                if (error)
3053                        return error;
3054        }
3055
3056        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3057        *stat = 1;
3058        return 0;
3059}
3060
3061/*
3062 * Single level of the btree record deletion routine.
3063 * Delete record pointed to by cur/level.
3064 * Remove the record from its block then rebalance the tree.
3065 * Return 0 for error, 1 for done, 2 to go on to the next level.
3066 */
3067STATIC int                                      /* error */
3068xfs_btree_delrec(
3069        struct xfs_btree_cur    *cur,           /* btree cursor */
3070        int                     level,          /* level removing record from */
3071        int                     *stat)          /* fail/done/go-on */
3072{
3073        struct xfs_btree_block  *block;         /* btree block */
3074        union xfs_btree_ptr     cptr;           /* current block ptr */
3075        struct xfs_buf          *bp;            /* buffer for block */
3076        int                     error;          /* error return value */
3077        int                     i;              /* loop counter */
3078        union xfs_btree_key     key;            /* storage for keyp */
3079        union xfs_btree_key     *keyp = &key;   /* passed to the next level */
3080        union xfs_btree_ptr     lptr;           /* left sibling block ptr */
3081        struct xfs_buf          *lbp;           /* left buffer pointer */
3082        struct xfs_btree_block  *left;          /* left btree block */
3083        int                     lrecs = 0;      /* left record count */
3084        int                     ptr;            /* key/record index */
3085        union xfs_btree_ptr     rptr;           /* right sibling block ptr */
3086        struct xfs_buf          *rbp;           /* right buffer pointer */
3087        struct xfs_btree_block  *right;         /* right btree block */
3088        struct xfs_btree_block  *rrblock;       /* right-right btree block */
3089        struct xfs_buf          *rrbp;          /* right-right buffer pointer */
3090        int                     rrecs = 0;      /* right record count */
3091        struct xfs_btree_cur    *tcur;          /* temporary btree cursor */
3092        int                     numrecs;        /* temporary numrec count */
3093
3094        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
3095        XFS_BTREE_TRACE_ARGI(cur, level);
3096
3097        tcur = NULL;
3098
3099        /* Get the index of the entry being deleted, check for nothing there. */
3100        ptr = cur->bc_ptrs[level];
3101        if (ptr == 0) {
3102                XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3103                *stat = 0;
3104                return 0;
3105        }
3106
3107        /* Get the buffer & block containing the record or key/ptr. */
3108        block = xfs_btree_get_block(cur, level, &bp);
3109        numrecs = xfs_btree_get_numrecs(block);
3110
3111#ifdef DEBUG
3112        error = xfs_btree_check_block(cur, block, level, bp);
3113        if (error)
3114                goto error0;
3115#endif
3116
3117        /* Fail if we're off the end of the block. */
3118        if (ptr > numrecs) {
3119                XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3120                *stat = 0;
3121                return 0;
3122        }
3123
3124        XFS_BTREE_STATS_INC(cur, delrec);
3125        XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr);
3126
3127        /* Excise the entries being deleted. */
3128        if (level > 0) {
3129                /* It's a nonleaf. operate on keys and ptrs */
3130                union xfs_btree_key     *lkp;
3131                union xfs_btree_ptr     *lpp;
3132
3133                lkp = xfs_btree_key_addr(cur, ptr + 1, block);
3134                lpp = xfs_btree_ptr_addr(cur, ptr + 1, block);
3135
3136#ifdef DEBUG
3137                for (i = 0; i < numrecs - ptr; i++) {
3138                        error = xfs_btree_check_ptr(cur, lpp, i, level);
3139                        if (error)
3140                                goto error0;
3141                }
3142#endif
3143
3144                if (ptr < numrecs) {
3145                        xfs_btree_shift_keys(cur, lkp, -1, numrecs - ptr);
3146                        xfs_btree_shift_ptrs(cur, lpp, -1, numrecs - ptr);
3147                        xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
3148                        xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
3149                }
3150
3151                /*
3152                 * If it's the first record in the block, we'll need to pass a
3153                 * key up to the next level (updkey).
3154                 */
3155                if (ptr == 1)
3156                        keyp = xfs_btree_key_addr(cur, 1, block);
3157        } else {
3158                /* It's a leaf. operate on records */
3159                if (ptr < numrecs) {
3160                        xfs_btree_shift_recs(cur,
3161                                xfs_btree_rec_addr(cur, ptr + 1, block),
3162                                -1, numrecs - ptr);
3163                        xfs_btree_log_recs(cur, bp, ptr, numrecs - 1);
3164                }
3165
3166                /*
3167                 * If it's the first record in the block, we'll need a key
3168                 * structure to pass up to the next level (updkey).
3169                 */
3170                if (ptr == 1) {
3171                        cur->bc_ops->init_key_from_rec(&key,
3172                                        xfs_btree_rec_addr(cur, 1, block));
3173                        keyp = &key;
3174                }
3175        }
3176
3177        /*
3178         * Decrement and log the number of entries in the block.
3179         */
3180        xfs_btree_set_numrecs(block, --numrecs);
3181        xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3182
3183        /*
3184         * If we are tracking the last record in the tree and
3185         * we are at the far right edge of the tree, update it.
3186         */
3187        if (xfs_btree_is_lastrec(cur, block, level)) {
3188                cur->bc_ops->update_lastrec(cur, block, NULL,
3189                                            ptr, LASTREC_DELREC);
3190        }
3191
3192        /*
3193         * We're at the root level.  First, shrink the root block in-memory.
3194         * Try to get rid of the next level down.  If we can't then there's
3195         * nothing left to do.
3196         */
3197        if (level == cur->bc_nlevels - 1) {
3198                if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3199                        xfs_iroot_realloc(cur->bc_private.b.ip, -1,
3200                                          cur->bc_private.b.whichfork);
3201
3202                        error = xfs_btree_kill_iroot(cur);
3203                        if (error)
3204                                goto error0;
3205
3206                        error = xfs_btree_dec_cursor(cur, level, stat);
3207                        if (error)
3208                                goto error0;
3209                        *stat = 1;
3210                        return 0;
3211                }
3212
3213                /*
3214                 * If this is the root level, and there's only one entry left,
3215                 * and it's NOT the leaf level, then we can get rid of this
3216                 * level.
3217                 */
3218                if (numrecs == 1 && level > 0) {
3219                        union xfs_btree_ptr     *pp;
3220                        /*
3221                         * pp is still set to the first pointer in the block.
3222                         * Make it the new root of the btree.
3223                         */
3224                        pp = xfs_btree_ptr_addr(cur, 1, block);
3225                        error = xfs_btree_kill_root(cur, bp, level, pp);
3226                        if (error)
3227                                goto error0;
3228                } else if (level > 0) {
3229                        error = xfs_btree_dec_cursor(cur, level, stat);
3230                        if (error)
3231                                goto error0;
3232                }
3233                *stat = 1;
3234                return 0;
3235        }
3236
3237        /*
3238         * If we deleted the leftmost entry in the block, update the
3239         * key values above us in the tree.
3240         */
3241        if (ptr == 1) {
3242                error = xfs_btree_updkey(cur, keyp, level + 1);
3243                if (error)
3244                        goto error0;
3245        }
3246
3247        /*
3248         * If the number of records remaining in the block is at least
3249         * the minimum, we're done.
3250         */
3251        if (numrecs >= cur->bc_ops->get_minrecs(cur, level)) {
3252                error = xfs_btree_dec_cursor(cur, level, stat);
3253                if (error)
3254                        goto error0;
3255                return 0;
3256        }
3257
3258        /*
3259         * Otherwise, we have to move some records around to keep the
3260         * tree balanced.  Look at the left and right sibling blocks to
3261         * see if we can re-balance by moving only one record.
3262         */
3263        xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3264        xfs_btree_get_sibling(cur, block, &lptr, XFS_BB_LEFTSIB);
3265
3266        if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3267                /*
3268                 * One child of root, need to get a chance to copy its contents
3269                 * into the root and delete it. Can't go up to next level,
3270                 * there's nothing to delete there.
3271                 */
3272                if (xfs_btree_ptr_is_null(cur, &rptr) &&
3273                    xfs_btree_ptr_is_null(cur, &lptr) &&
3274                    level == cur->bc_nlevels - 2) {
3275                        error = xfs_btree_kill_iroot(cur);
3276                        if (!error)
3277                                error = xfs_btree_dec_cursor(cur, level, stat);
3278                        if (error)
3279                                goto error0;
3280                        return 0;
3281                }
3282        }
3283
3284        ASSERT(!xfs_btree_ptr_is_null(cur, &rptr) ||
3285               !xfs_btree_ptr_is_null(cur, &lptr));
3286
3287        /*
3288         * Duplicate the cursor so our btree manipulations here won't
3289         * disrupt the next level up.
3290         */
3291        error = xfs_btree_dup_cursor(cur, &tcur);
3292        if (error)
3293                goto error0;
3294
3295        /*
3296         * If there's a right sibling, see if it's ok to shift an entry
3297         * out of it.
3298         */
3299        if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3300                /*
3301                 * Move the temp cursor to the last entry in the next block.
3302                 * Actually any entry but the first would suffice.
3303                 */
3304                i = xfs_btree_lastrec(tcur, level);
3305                XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3306
3307                error = xfs_btree_increment(tcur, level, &i);
3308                if (error)
3309                        goto error0;
3310                XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3311
3312                i = xfs_btree_lastrec(tcur, level);
3313                XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3314
3315                /* Grab a pointer to the block. */
3316                right = xfs_btree_get_block(tcur, level, &rbp);
3317#ifdef DEBUG
3318                error = xfs_btree_check_block(tcur, right, level, rbp);
3319                if (error)
3320                        goto error0;
3321#endif
3322                /* Grab the current block number, for future use. */
3323                xfs_btree_get_sibling(tcur, right, &cptr, XFS_BB_LEFTSIB);
3324
3325                /*
3326                 * If right block is full enough so that removing one entry
3327                 * won't make it too empty, and left-shifting an entry out
3328                 * of right to us works, we're done.
3329                 */
3330                if (xfs_btree_get_numrecs(right) - 1 >=
3331                    cur->bc_ops->get_minrecs(tcur, level)) {
3332                        error = xfs_btree_lshift(tcur, level, &i);
3333                        if (error)
3334                                goto error0;
3335                        if (i) {
3336                                ASSERT(xfs_btree_get_numrecs(block) >=
3337                                       cur->bc_ops->get_minrecs(tcur, level));
3338
3339                                xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3340                                tcur = NULL;
3341
3342                                error = xfs_btree_dec_cursor(cur, level, stat);
3343                                if (error)
3344                                        goto error0;
3345                                return 0;
3346                        }
3347                }
3348
3349                /*
3350                 * Otherwise, grab the number of records in right for
3351                 * future reference, and fix up the temp cursor to point
3352                 * to our block again (last record).
3353                 */
3354                rrecs = xfs_btree_get_numrecs(right);
3355                if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3356                        i = xfs_btree_firstrec(tcur, level);
3357                        XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3358
3359                        error = xfs_btree_decrement(tcur, level, &i);
3360                        if (error)
3361                                goto error0;
3362                        XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3363                }
3364        }
3365
3366        /*
3367         * If there's a left sibling, see if it's ok to shift an entry
3368         * out of it.
3369         */
3370        if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3371                /*
3372                 * Move the temp cursor to the first entry in the
3373                 * previous block.
3374                 */
3375                i = xfs_btree_firstrec(tcur, level);
3376                XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3377
3378                error = xfs_btree_decrement(tcur, level, &i);
3379                if (error)
3380                        goto error0;
3381                i = xfs_btree_firstrec(tcur, level);
3382                XFS_WANT_CORRUPTED_GOTO(i == 1, error0);
3383
3384                /* Grab a pointer to the block. */
3385                left = xfs_btree_get_block(tcur, level, &lbp);
3386#ifdef DEBUG
3387                error = xfs_btree_check_block(cur, left, level, lbp);
3388                if (error)
3389                        goto error0;
3390#endif
3391                /* Grab the current block number, for future use. */
3392                xfs_btree_get_sibling(tcur, left, &cptr, XFS_BB_RIGHTSIB);
3393
3394                /*
3395                 * If left block is full enough so that removing one entry
3396                 * won't make it too empty, and right-shifting an entry out
3397                 * of left to us works, we're done.
3398                 */
3399                if (xfs_btree_get_numrecs(left) - 1 >=
3400                    cur->bc_ops->get_minrecs(tcur, level)) {
3401                        error = xfs_btree_rshift(tcur, level, &i);
3402                        if (error)
3403                                goto error0;
3404                        if (i) {
3405                                ASSERT(xfs_btree_get_numrecs(block) >=
3406                                       cur->bc_ops->get_minrecs(tcur, level));
3407                                xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3408                                tcur = NULL;
3409                                if (level == 0)
3410                                        cur->bc_ptrs[0]++;
3411                                XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3412                                *stat = 1;
3413                                return 0;
3414                        }
3415                }
3416
3417                /*
3418                 * Otherwise, grab the number of records in right for
3419                 * future reference.
3420                 */
3421                lrecs = xfs_btree_get_numrecs(left);
3422        }
3423
3424        /* Delete the temp cursor, we're done with it. */
3425        xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3426        tcur = NULL;
3427
3428        /* If here, we need to do a join to keep the tree balanced. */
3429        ASSERT(!xfs_btree_ptr_is_null(cur, &cptr));
3430
3431        if (!xfs_btree_ptr_is_null(cur, &lptr) &&
3432            lrecs + xfs_btree_get_numrecs(block) <=
3433                        cur->bc_ops->get_maxrecs(cur, level)) {
3434                /*
3435                 * Set "right" to be the starting block,
3436                 * "left" to be the left neighbor.
3437                 */
3438                rptr = cptr;
3439                right = block;
3440                rbp = bp;
3441                error = xfs_btree_read_buf_block(cur, &lptr, level,
3442                                                        0, &left, &lbp);
3443                if (error)
3444                        goto error0;
3445
3446        /*
3447         * If that won't work, see if we can join with the right neighbor block.
3448         */
3449        } else if (!xfs_btree_ptr_is_null(cur, &rptr) &&
3450                   rrecs + xfs_btree_get_numrecs(block) <=
3451                        cur->bc_ops->get_maxrecs(cur, level)) {
3452                /*
3453                 * Set "left" to be the starting block,
3454                 * "right" to be the right neighbor.
3455                 */
3456                lptr = cptr;
3457                left = block;
3458                lbp = bp;
3459                error = xfs_btree_read_buf_block(cur, &rptr, level,
3460                                                        0, &right, &rbp);
3461                if (error)
3462                        goto error0;
3463
3464        /*
3465         * Otherwise, we can't fix the imbalance.
3466         * Just return.  This is probably a logic error, but it's not fatal.
3467         */
3468        } else {
3469                error = xfs_btree_dec_cursor(cur, level, stat);
3470                if (error)
3471                        goto error0;
3472                return 0;
3473        }
3474
3475        rrecs = xfs_btree_get_numrecs(right);
3476        lrecs = xfs_btree_get_numrecs(left);
3477
3478        /*
3479         * We're now going to join "left" and "right" by moving all the stuff
3480         * in "right" to "left" and deleting "right".
3481         */
3482        XFS_BTREE_STATS_ADD(cur, moves, rrecs);
3483        if (level > 0) {
3484                /* It's a non-leaf.  Move keys and pointers. */
3485                union xfs_btree_key     *lkp;   /* left btree key */
3486                union xfs_btree_ptr     *lpp;   /* left address pointer */
3487                union xfs_btree_key     *rkp;   /* right btree key */
3488                union xfs_btree_ptr     *rpp;   /* right address pointer */
3489
3490                lkp = xfs_btree_key_addr(cur, lrecs + 1, left);
3491                lpp = xfs_btree_ptr_addr(cur, lrecs + 1, left);
3492                rkp = xfs_btree_key_addr(cur, 1, right);
3493                rpp = xfs_btree_ptr_addr(cur, 1, right);
3494#ifdef DEBUG
3495                for (i = 1; i < rrecs; i++) {
3496                        error = xfs_btree_check_ptr(cur, rpp, i, level);
3497                        if (error)
3498                                goto error0;
3499                }
3500#endif
3501                xfs_btree_copy_keys(cur, lkp, rkp, rrecs);
3502                xfs_btree_copy_ptrs(cur, lpp, rpp, rrecs);
3503
3504                xfs_btree_log_keys(cur, lbp, lrecs + 1, lrecs + rrecs);
3505                xfs_btree_log_ptrs(cur, lbp, lrecs + 1, lrecs + rrecs);
3506        } else {
3507                /* It's a leaf.  Move records.  */
3508                union xfs_btree_rec     *lrp;   /* left record pointer */
3509                union xfs_btree_rec     *rrp;   /* right record pointer */
3510
3511                lrp = xfs_btree_rec_addr(cur, lrecs + 1, left);
3512                rrp = xfs_btree_rec_addr(cur, 1, right);
3513
3514                xfs_btree_copy_recs(cur, lrp, rrp, rrecs);
3515                xfs_btree_log_recs(cur, lbp, lrecs + 1, lrecs + rrecs);
3516        }
3517
3518        XFS_BTREE_STATS_INC(cur, join);
3519
3520        /*
3521         * Fix up the number of records and right block pointer in the
3522         * surviving block, and log it.
3523         */
3524        xfs_btree_set_numrecs(left, lrecs + rrecs);
3525        xfs_btree_get_sibling(cur, right, &cptr, XFS_BB_RIGHTSIB),
3526        xfs_btree_set_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
3527        xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
3528
3529        /* If there is a right sibling, point it to the remaining block. */
3530        xfs_btree_get_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
3531        if (!xfs_btree_ptr_is_null(cur, &cptr)) {
3532                error = xfs_btree_read_buf_block(cur, &cptr, level,
3533                                                        0, &rrblock, &rrbp);
3534                if (error)
3535                        goto error0;
3536                xfs_btree_set_sibling(cur, rrblock, &lptr, XFS_BB_LEFTSIB);
3537                xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
3538        }
3539
3540        /* Free the deleted block. */
3541        error = cur->bc_ops->free_block(cur, rbp);
3542        if (error)
3543                goto error0;
3544        XFS_BTREE_STATS_INC(cur, free);
3545
3546        /*
3547         * If we joined with the left neighbor, set the buffer in the
3548         * cursor to the left block, and fix up the index.
3549         */
3550        if (bp != lbp) {
3551                cur->bc_bufs[level] = lbp;
3552                cur->bc_ptrs[level] += lrecs;
3553                cur->bc_ra[level] = 0;
3554        }
3555        /*
3556         * If we joined with the right neighbor and there's a level above
3557         * us, increment the cursor at that level.
3558         */
3559        else if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) ||
3560                   (level + 1 < cur->bc_nlevels)) {
3561                error = xfs_btree_increment(cur, level + 1, &i);
3562                if (error)
3563                        goto error0;
3564        }
3565
3566        /*
3567         * Readjust the ptr at this level if it's not a leaf, since it's
3568         * still pointing at the deletion point, which makes the cursor
3569         * inconsistent.  If this makes the ptr 0, the caller fixes it up.
3570         * We can't use decrement because it would change the next level up.
3571         */
3572        if (level > 0)
3573                cur->bc_ptrs[level]--;
3574
3575        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3576        /* Return value means the next level up has something to do. */
3577        *stat = 2;
3578        return 0;
3579
3580error0:
3581        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
3582        if (tcur)
3583                xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
3584        return error;
3585}
3586
3587/*
3588 * Delete the record pointed to by cur.
3589 * The cursor refers to the place where the record was (could be inserted)
3590 * when the operation returns.
3591 */
3592int                                     /* error */
3593xfs_btree_delete(
3594        struct xfs_btree_cur    *cur,
3595        int                     *stat)  /* success/failure */
3596{
3597        int                     error;  /* error return value */
3598        int                     level;
3599        int                     i;
3600
3601        XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
3602
3603        /*
3604         * Go up the tree, starting at leaf level.
3605         *
3606         * If 2 is returned then a join was done; go to the next level.
3607         * Otherwise we are done.
3608         */
3609        for (level = 0, i = 2; i == 2; level++) {
3610                error = xfs_btree_delrec(cur, level, &i);
3611                if (error)
3612                        goto error0;
3613        }
3614
3615        if (i == 0) {
3616                for (level = 1; level < cur->bc_nlevels; level++) {
3617                        if (cur->bc_ptrs[level] == 0) {
3618                                error = xfs_btree_decrement(cur, level, &i);
3619                                if (error)
3620                                        goto error0;
3621                                break;
3622                        }
3623                }
3624        }
3625
3626        XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
3627        *stat = i;
3628        return 0;
3629error0:
3630        XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
3631        return error;
3632}
3633
3634/*
3635 * Get the data from the pointed-to record.
3636 */
3637int                                     /* error */
3638xfs_btree_get_rec(
3639        struct xfs_btree_cur    *cur,   /* btree cursor */
3640        union xfs_btree_rec     **recp, /* output: btree record */
3641        int                     *stat)  /* output: success/failure */
3642{
3643        struct xfs_btree_block  *block; /* btree block */
3644        struct xfs_buf          *bp;    /* buffer pointer */
3645        int                     ptr;    /* record number */
3646#ifdef DEBUG
3647        int                     error;  /* error return value */
3648#endif
3649
3650        ptr = cur->bc_ptrs[0];
3651        block = xfs_btree_get_block(cur, 0, &bp);
3652
3653#ifdef DEBUG
3654        error = xfs_btree_check_block(cur, block, 0, bp);
3655        if (error)
3656                return error;
3657#endif
3658
3659        /*
3660         * Off the right end or left end, return failure.
3661         */
3662        if (ptr > xfs_btree_get_numrecs(block) || ptr <= 0) {
3663                *stat = 0;
3664                return 0;
3665        }
3666
3667        /*
3668         * Point to the record and extract its data.
3669         */
3670        *recp = xfs_btree_rec_addr(cur, ptr, block);
3671        *stat = 1;
3672        return 0;
3673}
3674
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