libxfs/xfs_btree.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
   4  * All Rights Reserved.
   5  */
   6 #include "xfs.h"
   7 #include "xfs_fs.h"
   8 #include "xfs_shared.h"
   9 #include "xfs_format.h"
  10 #include "xfs_log_format.h"
  11 #include "xfs_trans_resv.h"
  12 #include "xfs_bit.h"
  13 #include "xfs_mount.h"
  14 #include "xfs_inode.h"
  15 #include "xfs_trans.h"
  16 #include "xfs_buf_item.h"
  17 #include "xfs_btree.h"
  18 #include "xfs_errortag.h"
  19 #include "xfs_error.h"
  20 #include "xfs_trace.h"
  21 #include "xfs_alloc.h"
  22 #include "xfs_log.h"
  23 #include "xfs_btree_staging.h"
  24 #include "xfs_ag.h"
  25 #include "xfs_alloc_btree.h"
  26 #include "xfs_ialloc_btree.h"
  27 #include "xfs_bmap_btree.h"
  28 #include "xfs_rmap_btree.h"
  29 #include "xfs_refcount_btree.h"
  30
  31 /*
  32  * Btree magic numbers.
  33  */
  34 static const uint32_t xfs_magics[2][XFS_BTNUM_MAX] = {
  35         { XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, 0, XFS_BMAP_MAGIC, XFS_IBT_MAGIC,
  36           XFS_FIBT_MAGIC, 0 },
  37         { XFS_ABTB_CRC_MAGIC, XFS_ABTC_CRC_MAGIC, XFS_RMAP_CRC_MAGIC,
  38           XFS_BMAP_CRC_MAGIC, XFS_IBT_CRC_MAGIC, XFS_FIBT_CRC_MAGIC,
  39           XFS_REFC_CRC_MAGIC }
  40 };
  41
  42 uint32_t
  43 xfs_btree_magic(
  44         int                     crc,
  45         xfs_btnum_t             btnum)
  46 {
  47         uint32_t                magic = xfs_magics[crc][btnum];
  48
  49         /* Ensure we asked for crc for crc-only magics. */
  50         ASSERT(magic != 0);
  51         return magic;
  52 }
  53
  54 /*
  55  * These sibling pointer checks are optimised for null sibling pointers. This
  56  * happens a lot, and we don't need to byte swap at runtime if the sibling
  57  * pointer is NULL.
  58  *
  59  * These are explicitly marked at inline because the cost of calling them as
  60  * functions instead of inlining them is about 36 bytes extra code per call site
  61  * on x86-64. Yes, gcc-11 fails to inline them, and explicit inlining of these
  62  * two sibling check functions reduces the compiled code size by over 300
  63  * bytes.
  64  */
  65 static inline xfs_failaddr_t
  66 xfs_btree_check_lblock_siblings(
  67         struct xfs_mount        *mp,
  68         struct xfs_btree_cur    *cur,
  69         int                     level,
  70         xfs_fsblock_t           fsb,
  71         __be64                  dsibling)
  72 {
  73         xfs_fsblock_t           sibling;
  74
  75         if (dsibling == cpu_to_be64(NULLFSBLOCK))
  76                 return NULL;
  77
  78         sibling = be64_to_cpu(dsibling);
  79         if (sibling == fsb)
  80                 return __this_address;
  81         if (level >= 0) {
  82                 if (!xfs_btree_check_lptr(cur, sibling, level + 1))
  83                         return __this_address;
  84         } else {
  85                 if (!xfs_verify_fsbno(mp, sibling))
  86                         return __this_address;
  87         }
  88
  89         return NULL;
  90 }
  91
  92 static inline xfs_failaddr_t
  93 xfs_btree_check_sblock_siblings(
  94         struct xfs_perag        *pag,
  95         struct xfs_btree_cur    *cur,
  96         int                     level,
  97         xfs_agblock_t           agbno,
  98         __be32                  dsibling)
  99 {
 100         xfs_agblock_t           sibling;
 101
 102         if (dsibling == cpu_to_be32(NULLAGBLOCK))
 103                 return NULL;
 104
 105         sibling = be32_to_cpu(dsibling);
 106         if (sibling == agbno)
 107                 return __this_address;
 108         if (level >= 0) {
 109                 if (!xfs_btree_check_sptr(cur, sibling, level + 1))
 110                         return __this_address;
 111         } else {
 112                 if (!xfs_verify_agbno(pag, sibling))
 113                         return __this_address;
 114         }
 115         return NULL;
 116 }
 117
 118 /*
 119  * Check a long btree block header.  Return the address of the failing check,
 120  * or NULL if everything is ok.
 121  */
 122 xfs_failaddr_t
 123 __xfs_btree_check_lblock(
 124         struct xfs_btree_cur    *cur,
 125         struct xfs_btree_block  *block,
 126         int                     level,
 127         struct xfs_buf          *bp)
 128 {
 129         struct xfs_mount        *mp = cur->bc_mp;
 130         xfs_btnum_t             btnum = cur->bc_btnum;
 131         int                     crc = xfs_has_crc(mp);
 132         xfs_failaddr_t          fa;
 133         xfs_fsblock_t           fsb = NULLFSBLOCK;
 134
 135         if (crc) {
 136                 if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
 137                         return __this_address;
 138                 if (block->bb_u.l.bb_blkno !=
 139                     cpu_to_be64(bp ? xfs_buf_daddr(bp) : XFS_BUF_DADDR_NULL))
 140                         return __this_address;
 141                 if (block->bb_u.l.bb_pad != cpu_to_be32(0))
 142                         return __this_address;
 143         }
 144
 145         if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(crc, btnum))
 146                 return __this_address;
 147         if (be16_to_cpu(block->bb_level) != level)
 148                 return __this_address;
 149         if (be16_to_cpu(block->bb_numrecs) >
 150             cur->bc_ops->get_maxrecs(cur, level))
 151                 return __this_address;
 152
 153         if (bp)
 154                 fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
 155
 156         fa = xfs_btree_check_lblock_siblings(mp, cur, level, fsb,
 157                         block->bb_u.l.bb_leftsib);
 158         if (!fa)
 159                 fa = xfs_btree_check_lblock_siblings(mp, cur, level, fsb,
 160                                 block->bb_u.l.bb_rightsib);
 161         return fa;
 162 }
 163
 164 /* Check a long btree block header. */
 165 static int
 166 xfs_btree_check_lblock(
 167         struct xfs_btree_cur    *cur,
 168         struct xfs_btree_block  *block,
 169         int                     level,
 170         struct xfs_buf          *bp)
 171 {
 172         struct xfs_mount        *mp = cur->bc_mp;
 173         xfs_failaddr_t          fa;
 174
 175         fa = __xfs_btree_check_lblock(cur, block, level, bp);
 176         if (XFS_IS_CORRUPT(mp, fa != NULL) ||
 177             XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BTREE_CHECK_LBLOCK)) {
 178                 if (bp)
 179                         trace_xfs_btree_corrupt(bp, _RET_IP_);
 180                 return -EFSCORRUPTED;
 181         }
 182         return 0;
 183 }
 184
 185 /*
 186  * Check a short btree block header.  Return the address of the failing check,
 187  * or NULL if everything is ok.
 188  */
 189 xfs_failaddr_t
 190 __xfs_btree_check_sblock(
 191         struct xfs_btree_cur    *cur,
 192         struct xfs_btree_block  *block,
 193         int                     level,
 194         struct xfs_buf          *bp)
 195 {
 196         struct xfs_mount        *mp = cur->bc_mp;
 197         struct xfs_perag        *pag = cur->bc_ag.pag;
 198         xfs_btnum_t             btnum = cur->bc_btnum;
 199         int                     crc = xfs_has_crc(mp);
 200         xfs_failaddr_t          fa;
 201         xfs_agblock_t           agbno = NULLAGBLOCK;
 202
 203         if (crc) {
 204                 if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
 205                         return __this_address;
 206                 if (block->bb_u.s.bb_blkno !=
 207                     cpu_to_be64(bp ? xfs_buf_daddr(bp) : XFS_BUF_DADDR_NULL))
 208                         return __this_address;
 209         }
 210
 211         if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(crc, btnum))
 212                 return __this_address;
 213         if (be16_to_cpu(block->bb_level) != level)
 214                 return __this_address;
 215         if (be16_to_cpu(block->bb_numrecs) >
 216             cur->bc_ops->get_maxrecs(cur, level))
 217                 return __this_address;
 218
 219         if (bp)
 220                 agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
 221
 222         fa = xfs_btree_check_sblock_siblings(pag, cur, level, agbno,
 223                         block->bb_u.s.bb_leftsib);
 224         if (!fa)
 225                 fa = xfs_btree_check_sblock_siblings(pag, cur, level, agbno,
 226                                 block->bb_u.s.bb_rightsib);
 227         return fa;
 228 }
 229
 230 /* Check a short btree block header. */
 231 STATIC int
 232 xfs_btree_check_sblock(
 233         struct xfs_btree_cur    *cur,
 234         struct xfs_btree_block  *block,
 235         int                     level,
 236         struct xfs_buf          *bp)
 237 {
 238         struct xfs_mount        *mp = cur->bc_mp;
 239         xfs_failaddr_t          fa;
 240
 241         fa = __xfs_btree_check_sblock(cur, block, level, bp);
 242         if (XFS_IS_CORRUPT(mp, fa != NULL) ||
 243             XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BTREE_CHECK_SBLOCK)) {
 244                 if (bp)
 245                         trace_xfs_btree_corrupt(bp, _RET_IP_);
 246                 return -EFSCORRUPTED;
 247         }
 248         return 0;
 249 }
 250
 251 /*
 252  * Debug routine: check that block header is ok.
 253  */
 254 int
 255 xfs_btree_check_block(
 256         struct xfs_btree_cur    *cur,   /* btree cursor */
 257         struct xfs_btree_block  *block, /* generic btree block pointer */
 258         int                     level,  /* level of the btree block */
 259         struct xfs_buf          *bp)    /* buffer containing block, if any */
 260 {
 261         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 262                 return xfs_btree_check_lblock(cur, block, level, bp);
 263         else
 264                 return xfs_btree_check_sblock(cur, block, level, bp);
 265 }
 266
 267 /* Check that this long pointer is valid and points within the fs. */
 268 bool
 269 xfs_btree_check_lptr(
 270         struct xfs_btree_cur    *cur,
 271         xfs_fsblock_t           fsbno,
 272         int                     level)
 273 {
 274         if (level <= 0)
 275                 return false;
 276         return xfs_verify_fsbno(cur->bc_mp, fsbno);
 277 }
 278
 279 /* Check that this short pointer is valid and points within the AG. */
 280 bool
 281 xfs_btree_check_sptr(
 282         struct xfs_btree_cur    *cur,
 283         xfs_agblock_t           agbno,
 284         int                     level)
 285 {
 286         if (level <= 0)
 287                 return false;
 288         return xfs_verify_agbno(cur->bc_ag.pag, agbno);
 289 }
 290
 291 /*
 292  * Check that a given (indexed) btree pointer at a certain level of a
 293  * btree is valid and doesn't point past where it should.
 294  */
 295 static int
 296 xfs_btree_check_ptr(
 297         struct xfs_btree_cur            *cur,
 298         const union xfs_btree_ptr       *ptr,
 299         int                             index,
 300         int                             level)
 301 {
 302         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 303                 if (xfs_btree_check_lptr(cur, be64_to_cpu((&ptr->l)[index]),
 304                                 level))
 305                         return 0;
 306                 xfs_err(cur->bc_mp,
 307 "Inode %llu fork %d: Corrupt btree %d pointer at level %d index %d.",
 308                                 cur->bc_ino.ip->i_ino,
 309                                 cur->bc_ino.whichfork, cur->bc_btnum,
 310                                 level, index);
 311         } else {
 312                 if (xfs_btree_check_sptr(cur, be32_to_cpu((&ptr->s)[index]),
 313                                 level))
 314                         return 0;
 315                 xfs_err(cur->bc_mp,
 316 "AG %u: Corrupt btree %d pointer at level %d index %d.",
 317                                 cur->bc_ag.pag->pag_agno, cur->bc_btnum,
 318                                 level, index);
 319         }
 320
 321         return -EFSCORRUPTED;
 322 }
 323
 324 #ifdef DEBUG
 325 # define xfs_btree_debug_check_ptr      xfs_btree_check_ptr
 326 #else
 327 # define xfs_btree_debug_check_ptr(...) (0)
 328 #endif
 329
 330 /*
 331  * Calculate CRC on the whole btree block and stuff it into the
 332  * long-form btree header.
 333  *
 334  * Prior to calculting the CRC, pull the LSN out of the buffer log item and put
 335  * it into the buffer so recovery knows what the last modification was that made
 336  * it to disk.
 337  */
 338 void
 339 xfs_btree_lblock_calc_crc(
 340         struct xfs_buf          *bp)
 341 {
 342         struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
 343         struct xfs_buf_log_item *bip = bp->b_log_item;
 344
 345         if (!xfs_has_crc(bp->b_mount))
 346                 return;
 347         if (bip)
 348                 block->bb_u.l.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
 349         xfs_buf_update_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
 350 }
 351
 352 bool
 353 xfs_btree_lblock_verify_crc(
 354         struct xfs_buf          *bp)
 355 {
 356         struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
 357         struct xfs_mount        *mp = bp->b_mount;
 358
 359         if (xfs_has_crc(mp)) {
 360                 if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.l.bb_lsn)))
 361                         return false;
 362                 return xfs_buf_verify_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
 363         }
 364
 365         return true;
 366 }
 367
 368 /*
 369  * Calculate CRC on the whole btree block and stuff it into the
 370  * short-form btree header.
 371  *
 372  * Prior to calculting the CRC, pull the LSN out of the buffer log item and put
 373  * it into the buffer so recovery knows what the last modification was that made
 374  * it to disk.
 375  */
 376 void
 377 xfs_btree_sblock_calc_crc(
 378         struct xfs_buf          *bp)
 379 {
 380         struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
 381         struct xfs_buf_log_item *bip = bp->b_log_item;
 382
 383         if (!xfs_has_crc(bp->b_mount))
 384                 return;
 385         if (bip)
 386                 block->bb_u.s.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
 387         xfs_buf_update_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
 388 }
 389
 390 bool
 391 xfs_btree_sblock_verify_crc(
 392         struct xfs_buf          *bp)
 393 {
 394         struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
 395         struct xfs_mount        *mp = bp->b_mount;
 396
 397         if (xfs_has_crc(mp)) {
 398                 if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.s.bb_lsn)))
 399                         return false;
 400                 return xfs_buf_verify_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
 401         }
 402
 403         return true;
 404 }
 405
 406 static int
 407 xfs_btree_free_block(
 408         struct xfs_btree_cur    *cur,
 409         struct xfs_buf          *bp)
 410 {
 411         int                     error;
 412
 413         error = cur->bc_ops->free_block(cur, bp);
 414         if (!error) {
 415                 xfs_trans_binval(cur->bc_tp, bp);
 416                 XFS_BTREE_STATS_INC(cur, free);
 417         }
 418         return error;
 419 }
 420
 421 /*
 422  * Delete the btree cursor.
 423  */
 424 void
 425 xfs_btree_del_cursor(
 426         struct xfs_btree_cur    *cur,           /* btree cursor */
 427         int                     error)          /* del because of error */
 428 {
 429         int                     i;              /* btree level */
 430
 431         /*
 432          * Clear the buffer pointers and release the buffers. If we're doing
 433          * this because of an error, inspect all of the entries in the bc_bufs
 434          * array for buffers to be unlocked. This is because some of the btree
 435          * code works from level n down to 0, and if we get an error along the
 436          * way we won't have initialized all the entries down to 0.
 437          */
 438         for (i = 0; i < cur->bc_nlevels; i++) {
 439                 if (cur->bc_levels[i].bp)
 440                         xfs_trans_brelse(cur->bc_tp, cur->bc_levels[i].bp);
 441                 else if (!error)
 442                         break;
 443         }
 444
 445         /*
 446          * If we are doing a BMBT update, the number of unaccounted blocks
 447          * allocated during this cursor life time should be zero. If it's not
 448          * zero, then we should be shut down or on our way to shutdown due to
 449          * cancelling a dirty transaction on error.
 450          */
 451         ASSERT(cur->bc_btnum != XFS_BTNUM_BMAP || cur->bc_ino.allocated == 0 ||
 452                xfs_is_shutdown(cur->bc_mp) || error != 0);
 453         if (unlikely(cur->bc_flags & XFS_BTREE_STAGING))
 454                 kmem_free(cur->bc_ops);
 455         if (!(cur->bc_flags & XFS_BTREE_LONG_PTRS) && cur->bc_ag.pag)
 456                 xfs_perag_put(cur->bc_ag.pag);
 457         kmem_cache_free(cur->bc_cache, cur);
 458 }
 459
 460 /*
 461  * Duplicate the btree cursor.
 462  * Allocate a new one, copy the record, re-get the buffers.
 463  */
 464 int                                     /* error */
 465 xfs_btree_dup_cursor(
 466         struct xfs_btree_cur *cur,              /* input cursor */
 467         struct xfs_btree_cur **ncur)            /* output cursor */
 468 {
 469         struct xfs_buf  *bp;            /* btree block's buffer pointer */
 470         int             error;          /* error return value */
 471         int             i;              /* level number of btree block */
 472         xfs_mount_t     *mp;            /* mount structure for filesystem */
 473         struct xfs_btree_cur *new;              /* new cursor value */
 474         xfs_trans_t     *tp;            /* transaction pointer, can be NULL */
 475
 476         tp = cur->bc_tp;
 477         mp = cur->bc_mp;
 478
 479         /*
 480          * Allocate a new cursor like the old one.
 481          */
 482         new = cur->bc_ops->dup_cursor(cur);
 483
 484         /*
 485          * Copy the record currently in the cursor.
 486          */
 487         new->bc_rec = cur->bc_rec;
 488
 489         /*
 490          * For each level current, re-get the buffer and copy the ptr value.
 491          */
 492         for (i = 0; i < new->bc_nlevels; i++) {
 493                 new->bc_levels[i].ptr = cur->bc_levels[i].ptr;
 494                 new->bc_levels[i].ra = cur->bc_levels[i].ra;
 495                 bp = cur->bc_levels[i].bp;
 496                 if (bp) {
 497                         error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
 498                                                    xfs_buf_daddr(bp), mp->m_bsize,
 499                                                    0, &bp,
 500                                                    cur->bc_ops->buf_ops);
 501                         if (error) {
 502                                 xfs_btree_del_cursor(new, error);
 503                                 *ncur = NULL;
 504                                 return error;
 505                         }
 506                 }
 507                 new->bc_levels[i].bp = bp;
 508         }
 509         *ncur = new;
 510         return 0;
 511 }
 512
 513 /*
 514  * XFS btree block layout and addressing:
 515  *
 516  * There are two types of blocks in the btree: leaf and non-leaf blocks.
 517  *
 518  * The leaf record start with a header then followed by records containing
 519  * the values.  A non-leaf block also starts with the same header, and
 520  * then first contains lookup keys followed by an equal number of pointers
 521  * to the btree blocks at the previous level.
 522  *
 523  *              +--------+-------+-------+-------+-------+-------+-------+
 524  * Leaf:        | header | rec 1 | rec 2 | rec 3 | rec 4 | rec 5 | rec N |
 525  *              +--------+-------+-------+-------+-------+-------+-------+
 526  *
 527  *              +--------+-------+-------+-------+-------+-------+-------+
 528  * Non-Leaf:    | header | key 1 | key 2 | key N | ptr 1 | ptr 2 | ptr N |
 529  *              +--------+-------+-------+-------+-------+-------+-------+
 530  *
 531  * The header is called struct xfs_btree_block for reasons better left unknown
 532  * and comes in different versions for short (32bit) and long (64bit) block
 533  * pointers.  The record and key structures are defined by the btree instances
 534  * and opaque to the btree core.  The block pointers are simple disk endian
 535  * integers, available in a short (32bit) and long (64bit) variant.
 536  *
 537  * The helpers below calculate the offset of a given record, key or pointer
 538  * into a btree block (xfs_btree_*_offset) or return a pointer to the given
 539  * record, key or pointer (xfs_btree_*_addr).  Note that all addressing
 540  * inside the btree block is done using indices starting at one, not zero!
 541  *
 542  * If XFS_BTREE_OVERLAPPING is set, then this btree supports keys containing
 543  * overlapping intervals.  In such a tree, records are still sorted lowest to
 544  * highest and indexed by the smallest key value that refers to the record.
 545  * However, nodes are different: each pointer has two associated keys -- one
 546  * indexing the lowest key available in the block(s) below (the same behavior
 547  * as the key in a regular btree) and another indexing the highest key
 548  * available in the block(s) below.  Because records are /not/ sorted by the
 549  * highest key, all leaf block updates require us to compute the highest key
 550  * that matches any record in the leaf and to recursively update the high keys
 551  * in the nodes going further up in the tree, if necessary.  Nodes look like
 552  * this:
 553  *
 554  *              +--------+-----+-----+-----+-----+-----+-------+-------+-----+
 555  * Non-Leaf:    | header | lo1 | hi1 | lo2 | hi2 | ... | ptr 1 | ptr 2 | ... |
 556  *              +--------+-----+-----+-----+-----+-----+-------+-------+-----+
 557  *
 558  * To perform an interval query on an overlapped tree, perform the usual
 559  * depth-first search and use the low and high keys to decide if we can skip
 560  * that particular node.  If a leaf node is reached, return the records that
 561  * intersect the interval.  Note that an interval query may return numerous
 562  * entries.  For a non-overlapped tree, simply search for the record associated
 563  * with the lowest key and iterate forward until a non-matching record is
 564  * found.  Section 14.3 ("Interval Trees") of _Introduction to Algorithms_ by
 565  * Cormen, Leiserson, Rivest, and Stein (2nd or 3rd ed. only) discuss this in
 566  * more detail.
 567  *
 568  * Why do we care about overlapping intervals?  Let's say you have a bunch of
 569  * reverse mapping records on a reflink filesystem:
 570  *
 571  * 1: +- file A startblock B offset C length D -----------+
 572  * 2:      +- file E startblock F offset G length H --------------+
 573  * 3:      +- file I startblock F offset J length K --+
 574  * 4:                                                        +- file L... --+
 575  *
 576  * Now say we want to map block (B+D) into file A at offset (C+D).  Ideally,
 577  * we'd simply increment the length of record 1.  But how do we find the record
 578  * that ends at (B+D-1) (i.e. record 1)?  A LE lookup of (B+D-1) would return
 579  * record 3 because the keys are ordered first by startblock.  An interval
 580  * query would return records 1 and 2 because they both overlap (B+D-1), and
 581  * from that we can pick out record 1 as the appropriate left neighbor.
 582  *
 583  * In the non-overlapped case you can do a LE lookup and decrement the cursor
 584  * because a record's interval must end before the next record.
 585  */
 586
 587 /*
 588  * Return size of the btree block header for this btree instance.
 589  */
 590 static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur)
 591 {
 592         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 593                 if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS)
 594                         return XFS_BTREE_LBLOCK_CRC_LEN;
 595                 return XFS_BTREE_LBLOCK_LEN;
 596         }
 597         if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS)
 598                 return XFS_BTREE_SBLOCK_CRC_LEN;
 599         return XFS_BTREE_SBLOCK_LEN;
 600 }
 601
 602 /*
 603  * Return size of btree block pointers for this btree instance.
 604  */
 605 static inline size_t xfs_btree_ptr_len(struct xfs_btree_cur *cur)
 606 {
 607         return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
 608                 sizeof(__be64) : sizeof(__be32);
 609 }
 610
 611 /*
 612  * Calculate offset of the n-th record in a btree block.
 613  */
 614 STATIC size_t
 615 xfs_btree_rec_offset(
 616         struct xfs_btree_cur    *cur,
 617         int                     n)
 618 {
 619         return xfs_btree_block_len(cur) +
 620                 (n - 1) * cur->bc_ops->rec_len;
 621 }
 622
 623 /*
 624  * Calculate offset of the n-th key in a btree block.
 625  */
 626 STATIC size_t
 627 xfs_btree_key_offset(
 628         struct xfs_btree_cur    *cur,
 629         int                     n)
 630 {
 631         return xfs_btree_block_len(cur) +
 632                 (n - 1) * cur->bc_ops->key_len;
 633 }
 634
 635 /*
 636  * Calculate offset of the n-th high key in a btree block.
 637  */
 638 STATIC size_t
 639 xfs_btree_high_key_offset(
 640         struct xfs_btree_cur    *cur,
 641         int                     n)
 642 {
 643         return xfs_btree_block_len(cur) +
 644                 (n - 1) * cur->bc_ops->key_len + (cur->bc_ops->key_len / 2);
 645 }
 646
 647 /*
 648  * Calculate offset of the n-th block pointer in a btree block.
 649  */
 650 STATIC size_t
 651 xfs_btree_ptr_offset(
 652         struct xfs_btree_cur    *cur,
 653         int                     n,
 654         int                     level)
 655 {
 656         return xfs_btree_block_len(cur) +
 657                 cur->bc_ops->get_maxrecs(cur, level) * cur->bc_ops->key_len +
 658                 (n - 1) * xfs_btree_ptr_len(cur);
 659 }
 660
 661 /*
 662  * Return a pointer to the n-th record in the btree block.
 663  */
 664 union xfs_btree_rec *
 665 xfs_btree_rec_addr(
 666         struct xfs_btree_cur    *cur,
 667         int                     n,
 668         struct xfs_btree_block  *block)
 669 {
 670         return (union xfs_btree_rec *)
 671                 ((char *)block + xfs_btree_rec_offset(cur, n));
 672 }
 673
 674 /*
 675  * Return a pointer to the n-th key in the btree block.
 676  */
 677 union xfs_btree_key *
 678 xfs_btree_key_addr(
 679         struct xfs_btree_cur    *cur,
 680         int                     n,
 681         struct xfs_btree_block  *block)
 682 {
 683         return (union xfs_btree_key *)
 684                 ((char *)block + xfs_btree_key_offset(cur, n));
 685 }
 686
 687 /*
 688  * Return a pointer to the n-th high key in the btree block.
 689  */
 690 union xfs_btree_key *
 691 xfs_btree_high_key_addr(
 692         struct xfs_btree_cur    *cur,
 693         int                     n,
 694         struct xfs_btree_block  *block)
 695 {
 696         return (union xfs_btree_key *)
 697                 ((char *)block + xfs_btree_high_key_offset(cur, n));
 698 }
 699
 700 /*
 701  * Return a pointer to the n-th block pointer in the btree block.
 702  */
 703 union xfs_btree_ptr *
 704 xfs_btree_ptr_addr(
 705         struct xfs_btree_cur    *cur,
 706         int                     n,
 707         struct xfs_btree_block  *block)
 708 {
 709         int                     level = xfs_btree_get_level(block);
 710
 711         ASSERT(block->bb_level != 0);
 712
 713         return (union xfs_btree_ptr *)
 714                 ((char *)block + xfs_btree_ptr_offset(cur, n, level));
 715 }
 716
 717 struct xfs_ifork *
 718 xfs_btree_ifork_ptr(
 719         struct xfs_btree_cur    *cur)
 720 {
 721         ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
 722
 723         if (cur->bc_flags & XFS_BTREE_STAGING)
 724                 return cur->bc_ino.ifake->if_fork;
 725         return xfs_ifork_ptr(cur->bc_ino.ip, cur->bc_ino.whichfork);
 726 }
 727
 728 /*
 729  * Get the root block which is stored in the inode.
 730  *
 731  * For now this btree implementation assumes the btree root is always
 732  * stored in the if_broot field of an inode fork.
 733  */
 734 STATIC struct xfs_btree_block *
 735 xfs_btree_get_iroot(
 736         struct xfs_btree_cur    *cur)
 737 {
 738         struct xfs_ifork        *ifp = xfs_btree_ifork_ptr(cur);
 739
 740         return (struct xfs_btree_block *)ifp->if_broot;
 741 }
 742
 743 /*
 744  * Retrieve the block pointer from the cursor at the given level.
 745  * This may be an inode btree root or from a buffer.
 746  */
 747 struct xfs_btree_block *                /* generic btree block pointer */
 748 xfs_btree_get_block(
 749         struct xfs_btree_cur    *cur,   /* btree cursor */
 750         int                     level,  /* level in btree */
 751         struct xfs_buf          **bpp)  /* buffer containing the block */
 752 {
 753         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
 754             (level == cur->bc_nlevels - 1)) {
 755                 *bpp = NULL;
 756                 return xfs_btree_get_iroot(cur);
 757         }
 758
 759         *bpp = cur->bc_levels[level].bp;
 760         return XFS_BUF_TO_BLOCK(*bpp);
 761 }
 762
 763 /*
 764  * Change the cursor to point to the first record at the given level.
 765  * Other levels are unaffected.
 766  */
 767 STATIC int                              /* success=1, failure=0 */
 768 xfs_btree_firstrec(
 769         struct xfs_btree_cur    *cur,   /* btree cursor */
 770         int                     level)  /* level to change */
 771 {
 772         struct xfs_btree_block  *block; /* generic btree block pointer */
 773         struct xfs_buf          *bp;    /* buffer containing block */
 774
 775         /*
 776          * Get the block pointer for this level.
 777          */
 778         block = xfs_btree_get_block(cur, level, &bp);
 779         if (xfs_btree_check_block(cur, block, level, bp))
 780                 return 0;
 781         /*
 782          * It's empty, there is no such record.
 783          */
 784         if (!block->bb_numrecs)
 785                 return 0;
 786         /*
 787          * Set the ptr value to 1, that's the first record/key.
 788          */
 789         cur->bc_levels[level].ptr = 1;
 790         return 1;
 791 }
 792
 793 /*
 794  * Change the cursor to point to the last record in the current block
 795  * at the given level.  Other levels are unaffected.
 796  */
 797 STATIC int                              /* success=1, failure=0 */
 798 xfs_btree_lastrec(
 799         struct xfs_btree_cur    *cur,   /* btree cursor */
 800         int                     level)  /* level to change */
 801 {
 802         struct xfs_btree_block  *block; /* generic btree block pointer */
 803         struct xfs_buf          *bp;    /* buffer containing block */
 804
 805         /*
 806          * Get the block pointer for this level.
 807          */
 808         block = xfs_btree_get_block(cur, level, &bp);
 809         if (xfs_btree_check_block(cur, block, level, bp))
 810                 return 0;
 811         /*
 812          * It's empty, there is no such record.
 813          */
 814         if (!block->bb_numrecs)
 815                 return 0;
 816         /*
 817          * Set the ptr value to numrecs, that's the last record/key.
 818          */
 819         cur->bc_levels[level].ptr = be16_to_cpu(block->bb_numrecs);
 820         return 1;
 821 }
 822
 823 /*
 824  * Compute first and last byte offsets for the fields given.
 825  * Interprets the offsets table, which contains struct field offsets.
 826  */
 827 void
 828 xfs_btree_offsets(
 829         uint32_t        fields,         /* bitmask of fields */
 830         const short     *offsets,       /* table of field offsets */
 831         int             nbits,          /* number of bits to inspect */
 832         int             *first,         /* output: first byte offset */
 833         int             *last)          /* output: last byte offset */
 834 {
 835         int             i;              /* current bit number */
 836         uint32_t        imask;          /* mask for current bit number */
 837
 838         ASSERT(fields != 0);
 839         /*
 840          * Find the lowest bit, so the first byte offset.
 841          */
 842         for (i = 0, imask = 1u; ; i++, imask <<= 1) {
 843                 if (imask & fields) {
 844                         *first = offsets[i];
 845                         break;
 846                 }
 847         }
 848         /*
 849          * Find the highest bit, so the last byte offset.
 850          */
 851         for (i = nbits - 1, imask = 1u << i; ; i--, imask >>= 1) {
 852                 if (imask & fields) {
 853                         *last = offsets[i + 1] - 1;
 854                         break;
 855                 }
 856         }
 857 }
 858
 859 /*
 860  * Get a buffer for the block, return it read in.
 861  * Long-form addressing.
 862  */
 863 int
 864 xfs_btree_read_bufl(
 865         struct xfs_mount        *mp,            /* file system mount point */
 866         struct xfs_trans        *tp,            /* transaction pointer */
 867         xfs_fsblock_t           fsbno,          /* file system block number */
 868         struct xfs_buf          **bpp,          /* buffer for fsbno */
 869         int                     refval,         /* ref count value for buffer */
 870         const struct xfs_buf_ops *ops)
 871 {
 872         struct xfs_buf          *bp;            /* return value */
 873         xfs_daddr_t             d;              /* real disk block address */
 874         int                     error;
 875
 876         if (!xfs_verify_fsbno(mp, fsbno))
 877                 return -EFSCORRUPTED;
 878         d = XFS_FSB_TO_DADDR(mp, fsbno);
 879         error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
 880                                    mp->m_bsize, 0, &bp, ops);
 881         if (error)
 882                 return error;
 883         if (bp)
 884                 xfs_buf_set_ref(bp, refval);
 885         *bpp = bp;
 886         return 0;
 887 }
 888
 889 /*
 890  * Read-ahead the block, don't wait for it, don't return a buffer.
 891  * Long-form addressing.
 892  */
 893 /* ARGSUSED */
 894 void
 895 xfs_btree_reada_bufl(
 896         struct xfs_mount        *mp,            /* file system mount point */
 897         xfs_fsblock_t           fsbno,          /* file system block number */
 898         xfs_extlen_t            count,          /* count of filesystem blocks */
 899         const struct xfs_buf_ops *ops)
 900 {
 901         xfs_daddr_t             d;
 902
 903         ASSERT(fsbno != NULLFSBLOCK);
 904         d = XFS_FSB_TO_DADDR(mp, fsbno);
 905         xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count, ops);
 906 }
 907
 908 /*
 909  * Read-ahead the block, don't wait for it, don't return a buffer.
 910  * Short-form addressing.
 911  */
 912 /* ARGSUSED */
 913 void
 914 xfs_btree_reada_bufs(
 915         struct xfs_mount        *mp,            /* file system mount point */
 916         xfs_agnumber_t          agno,           /* allocation group number */
 917         xfs_agblock_t           agbno,          /* allocation group block number */
 918         xfs_extlen_t            count,          /* count of filesystem blocks */
 919         const struct xfs_buf_ops *ops)
 920 {
 921         xfs_daddr_t             d;
 922
 923         ASSERT(agno != NULLAGNUMBER);
 924         ASSERT(agbno != NULLAGBLOCK);
 925         d = XFS_AGB_TO_DADDR(mp, agno, agbno);
 926         xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count, ops);
 927 }
 928
 929 STATIC int
 930 xfs_btree_readahead_lblock(
 931         struct xfs_btree_cur    *cur,
 932         int                     lr,
 933         struct xfs_btree_block  *block)
 934 {
 935         int                     rval = 0;
 936         xfs_fsblock_t           left = be64_to_cpu(block->bb_u.l.bb_leftsib);
 937         xfs_fsblock_t           right = be64_to_cpu(block->bb_u.l.bb_rightsib);
 938
 939         if ((lr & XFS_BTCUR_LEFTRA) && left != NULLFSBLOCK) {
 940                 xfs_btree_reada_bufl(cur->bc_mp, left, 1,
 941                                      cur->bc_ops->buf_ops);
 942                 rval++;
 943         }
 944
 945         if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLFSBLOCK) {
 946                 xfs_btree_reada_bufl(cur->bc_mp, right, 1,
 947                                      cur->bc_ops->buf_ops);
 948                 rval++;
 949         }
 950
 951         return rval;
 952 }
 953
 954 STATIC int
 955 xfs_btree_readahead_sblock(
 956         struct xfs_btree_cur    *cur,
 957         int                     lr,
 958         struct xfs_btree_block *block)
 959 {
 960         int                     rval = 0;
 961         xfs_agblock_t           left = be32_to_cpu(block->bb_u.s.bb_leftsib);
 962         xfs_agblock_t           right = be32_to_cpu(block->bb_u.s.bb_rightsib);
 963
 964
 965         if ((lr & XFS_BTCUR_LEFTRA) && left != NULLAGBLOCK) {
 966                 xfs_btree_reada_bufs(cur->bc_mp, cur->bc_ag.pag->pag_agno,
 967                                      left, 1, cur->bc_ops->buf_ops);
 968                 rval++;
 969         }
 970
 971         if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {
 972                 xfs_btree_reada_bufs(cur->bc_mp, cur->bc_ag.pag->pag_agno,
 973                                      right, 1, cur->bc_ops->buf_ops);
 974                 rval++;
 975         }
 976
 977         return rval;
 978 }
 979
 980 /*
 981  * Read-ahead btree blocks, at the given level.
 982  * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
 983  */
 984 STATIC int
 985 xfs_btree_readahead(
 986         struct xfs_btree_cur    *cur,           /* btree cursor */
 987         int                     lev,            /* level in btree */
 988         int                     lr)             /* left/right bits */
 989 {
 990         struct xfs_btree_block  *block;
 991
 992         /*
 993          * No readahead needed if we are at the root level and the
 994          * btree root is stored in the inode.
 995          */
 996         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
 997             (lev == cur->bc_nlevels - 1))
 998                 return 0;
 999
1000         if ((cur->bc_levels[lev].ra | lr) == cur->bc_levels[lev].ra)
1001                 return 0;
1002
1003         cur->bc_levels[lev].ra |= lr;
1004         block = XFS_BUF_TO_BLOCK(cur->bc_levels[lev].bp);
1005
1006         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1007                 return xfs_btree_readahead_lblock(cur, lr, block);
1008         return xfs_btree_readahead_sblock(cur, lr, block);
1009 }
1010
1011 STATIC int
1012 xfs_btree_ptr_to_daddr(
1013         struct xfs_btree_cur            *cur,
1014         const union xfs_btree_ptr       *ptr,
1015         xfs_daddr_t                     *daddr)
1016 {
1017         xfs_fsblock_t           fsbno;
1018         xfs_agblock_t           agbno;
1019         int                     error;
1020
1021         error = xfs_btree_check_ptr(cur, ptr, 0, 1);
1022         if (error)
1023                 return error;
1024
1025         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1026                 fsbno = be64_to_cpu(ptr->l);
1027                 *daddr = XFS_FSB_TO_DADDR(cur->bc_mp, fsbno);
1028         } else {
1029                 agbno = be32_to_cpu(ptr->s);
1030                 *daddr = XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_ag.pag->pag_agno,
1031                                 agbno);
1032         }
1033
1034         return 0;
1035 }
1036
1037 /*
1038  * Readahead @count btree blocks at the given @ptr location.
1039  *
1040  * We don't need to care about long or short form btrees here as we have a
1041  * method of converting the ptr directly to a daddr available to us.
1042  */
1043 STATIC void
1044 xfs_btree_readahead_ptr(
1045         struct xfs_btree_cur    *cur,
1046         union xfs_btree_ptr     *ptr,
1047         xfs_extlen_t            count)
1048 {
1049         xfs_daddr_t             daddr;
1050
1051         if (xfs_btree_ptr_to_daddr(cur, ptr, &daddr))
1052                 return;
1053         xfs_buf_readahead(cur->bc_mp->m_ddev_targp, daddr,
1054                           cur->bc_mp->m_bsize * count, cur->bc_ops->buf_ops);
1055 }
1056
1057 /*
1058  * Set the buffer for level "lev" in the cursor to bp, releasing
1059  * any previous buffer.
1060  */
1061 STATIC void
1062 xfs_btree_setbuf(
1063         struct xfs_btree_cur    *cur,   /* btree cursor */
1064         int                     lev,    /* level in btree */
1065         struct xfs_buf          *bp)    /* new buffer to set */
1066 {
1067         struct xfs_btree_block  *b;     /* btree block */
1068
1069         if (cur->bc_levels[lev].bp)
1070                 xfs_trans_brelse(cur->bc_tp, cur->bc_levels[lev].bp);
1071         cur->bc_levels[lev].bp = bp;
1072         cur->bc_levels[lev].ra = 0;
1073
1074         b = XFS_BUF_TO_BLOCK(bp);
1075         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1076                 if (b->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK))
1077                         cur->bc_levels[lev].ra |= XFS_BTCUR_LEFTRA;
1078                 if (b->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK))
1079                         cur->bc_levels[lev].ra |= XFS_BTCUR_RIGHTRA;
1080         } else {
1081                 if (b->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK))
1082                         cur->bc_levels[lev].ra |= XFS_BTCUR_LEFTRA;
1083                 if (b->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK))
1084                         cur->bc_levels[lev].ra |= XFS_BTCUR_RIGHTRA;
1085         }
1086 }
1087
1088 bool
1089 xfs_btree_ptr_is_null(
1090         struct xfs_btree_cur            *cur,
1091         const union xfs_btree_ptr       *ptr)
1092 {
1093         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1094                 return ptr->l == cpu_to_be64(NULLFSBLOCK);
1095         else
1096                 return ptr->s == cpu_to_be32(NULLAGBLOCK);
1097 }
1098
1099 void
1100 xfs_btree_set_ptr_null(
1101         struct xfs_btree_cur    *cur,
1102         union xfs_btree_ptr     *ptr)
1103 {
1104         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1105                 ptr->l = cpu_to_be64(NULLFSBLOCK);
1106         else
1107                 ptr->s = cpu_to_be32(NULLAGBLOCK);
1108 }
1109
1110 /*
1111  * Get/set/init sibling pointers
1112  */
1113 void
1114 xfs_btree_get_sibling(
1115         struct xfs_btree_cur    *cur,
1116         struct xfs_btree_block  *block,
1117         union xfs_btree_ptr     *ptr,
1118         int                     lr)
1119 {
1120         ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1121
1122         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1123                 if (lr == XFS_BB_RIGHTSIB)
1124                         ptr->l = block->bb_u.l.bb_rightsib;
1125                 else
1126                         ptr->l = block->bb_u.l.bb_leftsib;
1127         } else {
1128                 if (lr == XFS_BB_RIGHTSIB)
1129                         ptr->s = block->bb_u.s.bb_rightsib;
1130                 else
1131                         ptr->s = block->bb_u.s.bb_leftsib;
1132         }
1133 }
1134
1135 void
1136 xfs_btree_set_sibling(
1137         struct xfs_btree_cur            *cur,
1138         struct xfs_btree_block          *block,
1139         const union xfs_btree_ptr       *ptr,
1140         int                             lr)
1141 {
1142         ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1143
1144         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1145                 if (lr == XFS_BB_RIGHTSIB)
1146                         block->bb_u.l.bb_rightsib = ptr->l;
1147                 else
1148                         block->bb_u.l.bb_leftsib = ptr->l;
1149         } else {
1150                 if (lr == XFS_BB_RIGHTSIB)
1151                         block->bb_u.s.bb_rightsib = ptr->s;
1152                 else
1153                         block->bb_u.s.bb_leftsib = ptr->s;
1154         }
1155 }
1156
1157 void
1158 xfs_btree_init_block_int(
1159         struct xfs_mount        *mp,
1160         struct xfs_btree_block  *buf,
1161         xfs_daddr_t             blkno,
1162         xfs_btnum_t             btnum,
1163         __u16                   level,
1164         __u16                   numrecs,
1165         __u64                   owner,
1166         unsigned int            flags)
1167 {
1168         int                     crc = xfs_has_crc(mp);
1169         __u32                   magic = xfs_btree_magic(crc, btnum);
1170
1171         buf->bb_magic = cpu_to_be32(magic);
1172         buf->bb_level = cpu_to_be16(level);
1173         buf->bb_numrecs = cpu_to_be16(numrecs);
1174
1175         if (flags & XFS_BTREE_LONG_PTRS) {
1176                 buf->bb_u.l.bb_leftsib = cpu_to_be64(NULLFSBLOCK);
1177                 buf->bb_u.l.bb_rightsib = cpu_to_be64(NULLFSBLOCK);
1178                 if (crc) {
1179                         buf->bb_u.l.bb_blkno = cpu_to_be64(blkno);
1180                         buf->bb_u.l.bb_owner = cpu_to_be64(owner);
1181                         uuid_copy(&buf->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid);
1182                         buf->bb_u.l.bb_pad = 0;
1183                         buf->bb_u.l.bb_lsn = 0;
1184                 }
1185         } else {
1186                 /* owner is a 32 bit value on short blocks */
1187                 __u32 __owner = (__u32)owner;
1188
1189                 buf->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
1190                 buf->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
1191                 if (crc) {
1192                         buf->bb_u.s.bb_blkno = cpu_to_be64(blkno);
1193                         buf->bb_u.s.bb_owner = cpu_to_be32(__owner);
1194                         uuid_copy(&buf->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid);
1195                         buf->bb_u.s.bb_lsn = 0;
1196                 }
1197         }
1198 }
1199
1200 void
1201 xfs_btree_init_block(
1202         struct xfs_mount *mp,
1203         struct xfs_buf  *bp,
1204         xfs_btnum_t     btnum,
1205         __u16           level,
1206         __u16           numrecs,
1207         __u64           owner)
1208 {
1209         xfs_btree_init_block_int(mp, XFS_BUF_TO_BLOCK(bp), xfs_buf_daddr(bp),
1210                                  btnum, level, numrecs, owner, 0);
1211 }
1212
1213 void
1214 xfs_btree_init_block_cur(
1215         struct xfs_btree_cur    *cur,
1216         struct xfs_buf          *bp,
1217         int                     level,
1218         int                     numrecs)
1219 {
1220         __u64                   owner;
1221
1222         /*
1223          * we can pull the owner from the cursor right now as the different
1224          * owners align directly with the pointer size of the btree. This may
1225          * change in future, but is safe for current users of the generic btree
1226          * code.
1227          */
1228         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1229                 owner = cur->bc_ino.ip->i_ino;
1230         else
1231                 owner = cur->bc_ag.pag->pag_agno;
1232
1233         xfs_btree_init_block_int(cur->bc_mp, XFS_BUF_TO_BLOCK(bp),
1234                                 xfs_buf_daddr(bp), cur->bc_btnum, level,
1235                                 numrecs, owner, cur->bc_flags);
1236 }
1237
1238 /*
1239  * Return true if ptr is the last record in the btree and
1240  * we need to track updates to this record.  The decision
1241  * will be further refined in the update_lastrec method.
1242  */
1243 STATIC int
1244 xfs_btree_is_lastrec(
1245         struct xfs_btree_cur    *cur,
1246         struct xfs_btree_block  *block,
1247         int                     level)
1248 {
1249         union xfs_btree_ptr     ptr;
1250
1251         if (level > 0)
1252                 return 0;
1253         if (!(cur->bc_flags & XFS_BTREE_LASTREC_UPDATE))
1254                 return 0;
1255
1256         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1257         if (!xfs_btree_ptr_is_null(cur, &ptr))
1258                 return 0;
1259         return 1;
1260 }
1261
1262 STATIC void
1263 xfs_btree_buf_to_ptr(
1264         struct xfs_btree_cur    *cur,
1265         struct xfs_buf          *bp,
1266         union xfs_btree_ptr     *ptr)
1267 {
1268         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1269                 ptr->l = cpu_to_be64(XFS_DADDR_TO_FSB(cur->bc_mp,
1270                                         xfs_buf_daddr(bp)));
1271         else {
1272                 ptr->s = cpu_to_be32(xfs_daddr_to_agbno(cur->bc_mp,
1273                                         xfs_buf_daddr(bp)));
1274         }
1275 }
1276
1277 STATIC void
1278 xfs_btree_set_refs(
1279         struct xfs_btree_cur    *cur,
1280         struct xfs_buf          *bp)
1281 {
1282         switch (cur->bc_btnum) {
1283         case XFS_BTNUM_BNO:
1284         case XFS_BTNUM_CNT:
1285                 xfs_buf_set_ref(bp, XFS_ALLOC_BTREE_REF);
1286                 break;
1287         case XFS_BTNUM_INO:
1288         case XFS_BTNUM_FINO:
1289                 xfs_buf_set_ref(bp, XFS_INO_BTREE_REF);
1290                 break;
1291         case XFS_BTNUM_BMAP:
1292                 xfs_buf_set_ref(bp, XFS_BMAP_BTREE_REF);
1293                 break;
1294         case XFS_BTNUM_RMAP:
1295                 xfs_buf_set_ref(bp, XFS_RMAP_BTREE_REF);
1296                 break;
1297         case XFS_BTNUM_REFC:
1298                 xfs_buf_set_ref(bp, XFS_REFC_BTREE_REF);
1299                 break;
1300         default:
1301                 ASSERT(0);
1302         }
1303 }
1304
1305 int
1306 xfs_btree_get_buf_block(
1307         struct xfs_btree_cur            *cur,
1308         const union xfs_btree_ptr       *ptr,
1309         struct xfs_btree_block          **block,
1310         struct xfs_buf                  **bpp)
1311 {
1312         struct xfs_mount        *mp = cur->bc_mp;
1313         xfs_daddr_t             d;
1314         int                     error;
1315
1316         error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
1317         if (error)
1318                 return error;
1319         error = xfs_trans_get_buf(cur->bc_tp, mp->m_ddev_targp, d, mp->m_bsize,
1320                         0, bpp);
1321         if (error)
1322                 return error;
1323
1324         (*bpp)->b_ops = cur->bc_ops->buf_ops;
1325         *block = XFS_BUF_TO_BLOCK(*bpp);
1326         return 0;
1327 }
1328
1329 /*
1330  * Read in the buffer at the given ptr and return the buffer and
1331  * the block pointer within the buffer.
1332  */
1333 STATIC int
1334 xfs_btree_read_buf_block(
1335         struct xfs_btree_cur            *cur,
1336         const union xfs_btree_ptr       *ptr,
1337         int                             flags,
1338         struct xfs_btree_block          **block,
1339         struct xfs_buf                  **bpp)
1340 {
1341         struct xfs_mount        *mp = cur->bc_mp;
1342         xfs_daddr_t             d;
1343         int                     error;
1344
1345         /* need to sort out how callers deal with failures first */
1346         ASSERT(!(flags & XBF_TRYLOCK));
1347
1348         error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
1349         if (error)
1350                 return error;
1351         error = xfs_trans_read_buf(mp, cur->bc_tp, mp->m_ddev_targp, d,
1352                                    mp->m_bsize, flags, bpp,
1353                                    cur->bc_ops->buf_ops);
1354         if (error)
1355                 return error;
1356
1357         xfs_btree_set_refs(cur, *bpp);
1358         *block = XFS_BUF_TO_BLOCK(*bpp);
1359         return 0;
1360 }
1361
1362 /*
1363  * Copy keys from one btree block to another.
1364  */
1365 void
1366 xfs_btree_copy_keys(
1367         struct xfs_btree_cur            *cur,
1368         union xfs_btree_key             *dst_key,
1369         const union xfs_btree_key       *src_key,
1370         int                             numkeys)
1371 {
1372         ASSERT(numkeys >= 0);
1373         memcpy(dst_key, src_key, numkeys * cur->bc_ops->key_len);
1374 }
1375
1376 /*
1377  * Copy records from one btree block to another.
1378  */
1379 STATIC void
1380 xfs_btree_copy_recs(
1381         struct xfs_btree_cur    *cur,
1382         union xfs_btree_rec     *dst_rec,
1383         union xfs_btree_rec     *src_rec,
1384         int                     numrecs)
1385 {
1386         ASSERT(numrecs >= 0);
1387         memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
1388 }
1389
1390 /*
1391  * Copy block pointers from one btree block to another.
1392  */
1393 void
1394 xfs_btree_copy_ptrs(
1395         struct xfs_btree_cur    *cur,
1396         union xfs_btree_ptr     *dst_ptr,
1397         const union xfs_btree_ptr *src_ptr,
1398         int                     numptrs)
1399 {
1400         ASSERT(numptrs >= 0);
1401         memcpy(dst_ptr, src_ptr, numptrs * xfs_btree_ptr_len(cur));
1402 }
1403
1404 /*
1405  * Shift keys one index left/right inside a single btree block.
1406  */
1407 STATIC void
1408 xfs_btree_shift_keys(
1409         struct xfs_btree_cur    *cur,
1410         union xfs_btree_key     *key,
1411         int                     dir,
1412         int                     numkeys)
1413 {
1414         char                    *dst_key;
1415
1416         ASSERT(numkeys >= 0);
1417         ASSERT(dir == 1 || dir == -1);
1418
1419         dst_key = (char *)key + (dir * cur->bc_ops->key_len);
1420         memmove(dst_key, key, numkeys * cur->bc_ops->key_len);
1421 }
1422
1423 /*
1424  * Shift records one index left/right inside a single btree block.
1425  */
1426 STATIC void
1427 xfs_btree_shift_recs(
1428         struct xfs_btree_cur    *cur,
1429         union xfs_btree_rec     *rec,
1430         int                     dir,
1431         int                     numrecs)
1432 {
1433         char                    *dst_rec;
1434
1435         ASSERT(numrecs >= 0);
1436         ASSERT(dir == 1 || dir == -1);
1437
1438         dst_rec = (char *)rec + (dir * cur->bc_ops->rec_len);
1439         memmove(dst_rec, rec, numrecs * cur->bc_ops->rec_len);
1440 }
1441
1442 /*
1443  * Shift block pointers one index left/right inside a single btree block.
1444  */
1445 STATIC void
1446 xfs_btree_shift_ptrs(
1447         struct xfs_btree_cur    *cur,
1448         union xfs_btree_ptr     *ptr,
1449         int                     dir,
1450         int                     numptrs)
1451 {
1452         char                    *dst_ptr;
1453
1454         ASSERT(numptrs >= 0);
1455         ASSERT(dir == 1 || dir == -1);
1456
1457         dst_ptr = (char *)ptr + (dir * xfs_btree_ptr_len(cur));
1458         memmove(dst_ptr, ptr, numptrs * xfs_btree_ptr_len(cur));
1459 }
1460
1461 /*
1462  * Log key values from the btree block.
1463  */
1464 STATIC void
1465 xfs_btree_log_keys(
1466         struct xfs_btree_cur    *cur,
1467         struct xfs_buf          *bp,
1468         int                     first,
1469         int                     last)
1470 {
1471
1472         if (bp) {
1473                 xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1474                 xfs_trans_log_buf(cur->bc_tp, bp,
1475                                   xfs_btree_key_offset(cur, first),
1476                                   xfs_btree_key_offset(cur, last + 1) - 1);
1477         } else {
1478                 xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1479                                 xfs_ilog_fbroot(cur->bc_ino.whichfork));
1480         }
1481 }
1482
1483 /*
1484  * Log record values from the btree block.
1485  */
1486 void
1487 xfs_btree_log_recs(
1488         struct xfs_btree_cur    *cur,
1489         struct xfs_buf          *bp,
1490         int                     first,
1491         int                     last)
1492 {
1493
1494         xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1495         xfs_trans_log_buf(cur->bc_tp, bp,
1496                           xfs_btree_rec_offset(cur, first),
1497                           xfs_btree_rec_offset(cur, last + 1) - 1);
1498
1499 }
1500
1501 /*
1502  * Log block pointer fields from a btree block (nonleaf).
1503  */
1504 STATIC void
1505 xfs_btree_log_ptrs(
1506         struct xfs_btree_cur    *cur,   /* btree cursor */
1507         struct xfs_buf          *bp,    /* buffer containing btree block */
1508         int                     first,  /* index of first pointer to log */
1509         int                     last)   /* index of last pointer to log */
1510 {
1511
1512         if (bp) {
1513                 struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
1514                 int                     level = xfs_btree_get_level(block);
1515
1516                 xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1517                 xfs_trans_log_buf(cur->bc_tp, bp,
1518                                 xfs_btree_ptr_offset(cur, first, level),
1519                                 xfs_btree_ptr_offset(cur, last + 1, level) - 1);
1520         } else {
1521                 xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1522                         xfs_ilog_fbroot(cur->bc_ino.whichfork));
1523         }
1524
1525 }
1526
1527 /*
1528  * Log fields from a btree block header.
1529  */
1530 void
1531 xfs_btree_log_block(
1532         struct xfs_btree_cur    *cur,   /* btree cursor */
1533         struct xfs_buf          *bp,    /* buffer containing btree block */
1534         uint32_t                fields) /* mask of fields: XFS_BB_... */
1535 {
1536         int                     first;  /* first byte offset logged */
1537         int                     last;   /* last byte offset logged */
1538         static const short      soffsets[] = {  /* table of offsets (short) */
1539                 offsetof(struct xfs_btree_block, bb_magic),
1540                 offsetof(struct xfs_btree_block, bb_level),
1541                 offsetof(struct xfs_btree_block, bb_numrecs),
1542                 offsetof(struct xfs_btree_block, bb_u.s.bb_leftsib),
1543                 offsetof(struct xfs_btree_block, bb_u.s.bb_rightsib),
1544                 offsetof(struct xfs_btree_block, bb_u.s.bb_blkno),
1545                 offsetof(struct xfs_btree_block, bb_u.s.bb_lsn),
1546                 offsetof(struct xfs_btree_block, bb_u.s.bb_uuid),
1547                 offsetof(struct xfs_btree_block, bb_u.s.bb_owner),
1548                 offsetof(struct xfs_btree_block, bb_u.s.bb_crc),
1549                 XFS_BTREE_SBLOCK_CRC_LEN
1550         };
1551         static const short      loffsets[] = {  /* table of offsets (long) */
1552                 offsetof(struct xfs_btree_block, bb_magic),
1553                 offsetof(struct xfs_btree_block, bb_level),
1554                 offsetof(struct xfs_btree_block, bb_numrecs),
1555                 offsetof(struct xfs_btree_block, bb_u.l.bb_leftsib),
1556                 offsetof(struct xfs_btree_block, bb_u.l.bb_rightsib),
1557                 offsetof(struct xfs_btree_block, bb_u.l.bb_blkno),
1558                 offsetof(struct xfs_btree_block, bb_u.l.bb_lsn),
1559                 offsetof(struct xfs_btree_block, bb_u.l.bb_uuid),
1560                 offsetof(struct xfs_btree_block, bb_u.l.bb_owner),
1561                 offsetof(struct xfs_btree_block, bb_u.l.bb_crc),
1562                 offsetof(struct xfs_btree_block, bb_u.l.bb_pad),
1563                 XFS_BTREE_LBLOCK_CRC_LEN
1564         };
1565
1566         if (bp) {
1567                 int nbits;
1568
1569                 if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS) {
1570                         /*
1571                          * We don't log the CRC when updating a btree
1572                          * block but instead recreate it during log
1573                          * recovery.  As the log buffers have checksums
1574                          * of their own this is safe and avoids logging a crc
1575                          * update in a lot of places.
1576                          */
1577                         if (fields == XFS_BB_ALL_BITS)
1578                                 fields = XFS_BB_ALL_BITS_CRC;
1579                         nbits = XFS_BB_NUM_BITS_CRC;
1580                 } else {
1581                         nbits = XFS_BB_NUM_BITS;
1582                 }
1583                 xfs_btree_offsets(fields,
1584                                   (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
1585                                         loffsets : soffsets,
1586                                   nbits, &first, &last);
1587                 xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1588                 xfs_trans_log_buf(cur->bc_tp, bp, first, last);
1589         } else {
1590                 xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1591                         xfs_ilog_fbroot(cur->bc_ino.whichfork));
1592         }
1593 }
1594
1595 /*
1596  * Increment cursor by one record at the level.
1597  * For nonzero levels the leaf-ward information is untouched.
1598  */
1599 int                                             /* error */
1600 xfs_btree_increment(
1601         struct xfs_btree_cur    *cur,
1602         int                     level,
1603         int                     *stat)          /* success/failure */
1604 {
1605         struct xfs_btree_block  *block;
1606         union xfs_btree_ptr     ptr;
1607         struct xfs_buf          *bp;
1608         int                     error;          /* error return value */
1609         int                     lev;
1610
1611         ASSERT(level < cur->bc_nlevels);
1612
1613         /* Read-ahead to the right at this level. */
1614         xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
1615
1616         /* Get a pointer to the btree block. */
1617         block = xfs_btree_get_block(cur, level, &bp);
1618
1619 #ifdef DEBUG
1620         error = xfs_btree_check_block(cur, block, level, bp);
1621         if (error)
1622                 goto error0;
1623 #endif
1624
1625         /* We're done if we remain in the block after the increment. */
1626         if (++cur->bc_levels[level].ptr <= xfs_btree_get_numrecs(block))
1627                 goto out1;
1628
1629         /* Fail if we just went off the right edge of the tree. */
1630         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1631         if (xfs_btree_ptr_is_null(cur, &ptr))
1632                 goto out0;
1633
1634         XFS_BTREE_STATS_INC(cur, increment);
1635
1636         /*
1637          * March up the tree incrementing pointers.
1638          * Stop when we don't go off the right edge of a block.
1639          */
1640         for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1641                 block = xfs_btree_get_block(cur, lev, &bp);
1642
1643 #ifdef DEBUG
1644                 error = xfs_btree_check_block(cur, block, lev, bp);
1645                 if (error)
1646                         goto error0;
1647 #endif
1648
1649                 if (++cur->bc_levels[lev].ptr <= xfs_btree_get_numrecs(block))
1650                         break;
1651
1652                 /* Read-ahead the right block for the next loop. */
1653                 xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);
1654         }
1655
1656         /*
1657          * If we went off the root then we are either seriously
1658          * confused or have the tree root in an inode.
1659          */
1660         if (lev == cur->bc_nlevels) {
1661                 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1662                         goto out0;
1663                 ASSERT(0);
1664                 error = -EFSCORRUPTED;
1665                 goto error0;
1666         }
1667         ASSERT(lev < cur->bc_nlevels);
1668
1669         /*
1670          * Now walk back down the tree, fixing up the cursor's buffer
1671          * pointers and key numbers.
1672          */
1673         for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1674                 union xfs_btree_ptr     *ptrp;
1675
1676                 ptrp = xfs_btree_ptr_addr(cur, cur->bc_levels[lev].ptr, block);
1677                 --lev;
1678                 error = xfs_btree_read_buf_block(cur, ptrp, 0, &block, &bp);
1679                 if (error)
1680                         goto error0;
1681
1682                 xfs_btree_setbuf(cur, lev, bp);
1683                 cur->bc_levels[lev].ptr = 1;
1684         }
1685 out1:
1686         *stat = 1;
1687         return 0;
1688
1689 out0:
1690         *stat = 0;
1691         return 0;
1692
1693 error0:
1694         return error;
1695 }
1696
1697 /*
1698  * Decrement cursor by one record at the level.
1699  * For nonzero levels the leaf-ward information is untouched.
1700  */
1701 int                                             /* error */
1702 xfs_btree_decrement(
1703         struct xfs_btree_cur    *cur,
1704         int                     level,
1705         int                     *stat)          /* success/failure */
1706 {
1707         struct xfs_btree_block  *block;
1708         struct xfs_buf          *bp;
1709         int                     error;          /* error return value */
1710         int                     lev;
1711         union xfs_btree_ptr     ptr;
1712
1713         ASSERT(level < cur->bc_nlevels);
1714
1715         /* Read-ahead to the left at this level. */
1716         xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);
1717
1718         /* We're done if we remain in the block after the decrement. */
1719         if (--cur->bc_levels[level].ptr > 0)
1720                 goto out1;
1721
1722         /* Get a pointer to the btree block. */
1723         block = xfs_btree_get_block(cur, level, &bp);
1724
1725 #ifdef DEBUG
1726         error = xfs_btree_check_block(cur, block, level, bp);
1727         if (error)
1728                 goto error0;
1729 #endif
1730
1731         /* Fail if we just went off the left edge of the tree. */
1732         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
1733         if (xfs_btree_ptr_is_null(cur, &ptr))
1734                 goto out0;
1735
1736         XFS_BTREE_STATS_INC(cur, decrement);
1737
1738         /*
1739          * March up the tree decrementing pointers.
1740          * Stop when we don't go off the left edge of a block.
1741          */
1742         for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1743                 if (--cur->bc_levels[lev].ptr > 0)
1744                         break;
1745                 /* Read-ahead the left block for the next loop. */
1746                 xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);
1747         }
1748
1749         /*
1750          * If we went off the root then we are seriously confused.
1751          * or the root of the tree is in an inode.
1752          */
1753         if (lev == cur->bc_nlevels) {
1754                 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1755                         goto out0;
1756                 ASSERT(0);
1757                 error = -EFSCORRUPTED;
1758                 goto error0;
1759         }
1760         ASSERT(lev < cur->bc_nlevels);
1761
1762         /*
1763          * Now walk back down the tree, fixing up the cursor's buffer
1764          * pointers and key numbers.
1765          */
1766         for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1767                 union xfs_btree_ptr     *ptrp;
1768
1769                 ptrp = xfs_btree_ptr_addr(cur, cur->bc_levels[lev].ptr, block);
1770                 --lev;
1771                 error = xfs_btree_read_buf_block(cur, ptrp, 0, &block, &bp);
1772                 if (error)
1773                         goto error0;
1774                 xfs_btree_setbuf(cur, lev, bp);
1775                 cur->bc_levels[lev].ptr = xfs_btree_get_numrecs(block);
1776         }
1777 out1:
1778         *stat = 1;
1779         return 0;
1780
1781 out0:
1782         *stat = 0;
1783         return 0;
1784
1785 error0:
1786         return error;
1787 }
1788
1789 int
1790 xfs_btree_lookup_get_block(
1791         struct xfs_btree_cur            *cur,   /* btree cursor */
1792         int                             level,  /* level in the btree */
1793         const union xfs_btree_ptr       *pp,    /* ptr to btree block */
1794         struct xfs_btree_block          **blkp) /* return btree block */
1795 {
1796         struct xfs_buf          *bp;    /* buffer pointer for btree block */
1797         xfs_daddr_t             daddr;
1798         int                     error = 0;
1799
1800         /* special case the root block if in an inode */
1801         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1802             (level == cur->bc_nlevels - 1)) {
1803                 *blkp = xfs_btree_get_iroot(cur);
1804                 return 0;
1805         }
1806
1807         /*
1808          * If the old buffer at this level for the disk address we are
1809          * looking for re-use it.
1810          *
1811          * Otherwise throw it away and get a new one.
1812          */
1813         bp = cur->bc_levels[level].bp;
1814         error = xfs_btree_ptr_to_daddr(cur, pp, &daddr);
1815         if (error)
1816                 return error;
1817         if (bp && xfs_buf_daddr(bp) == daddr) {
1818                 *blkp = XFS_BUF_TO_BLOCK(bp);
1819                 return 0;
1820         }
1821
1822         error = xfs_btree_read_buf_block(cur, pp, 0, blkp, &bp);
1823         if (error)
1824                 return error;
1825
1826         /* Check the inode owner since the verifiers don't. */
1827         if (xfs_has_crc(cur->bc_mp) &&
1828             !(cur->bc_ino.flags & XFS_BTCUR_BMBT_INVALID_OWNER) &&
1829             (cur->bc_flags & XFS_BTREE_LONG_PTRS) &&
1830             be64_to_cpu((*blkp)->bb_u.l.bb_owner) !=
1831                         cur->bc_ino.ip->i_ino)
1832                 goto out_bad;
1833
1834         /* Did we get the level we were looking for? */
1835         if (be16_to_cpu((*blkp)->bb_level) != level)
1836                 goto out_bad;
1837
1838         /* Check that internal nodes have at least one record. */
1839         if (level != 0 && be16_to_cpu((*blkp)->bb_numrecs) == 0)
1840                 goto out_bad;
1841
1842         xfs_btree_setbuf(cur, level, bp);
1843         return 0;
1844
1845 out_bad:
1846         *blkp = NULL;
1847         xfs_buf_mark_corrupt(bp);
1848         xfs_trans_brelse(cur->bc_tp, bp);
1849         return -EFSCORRUPTED;
1850 }
1851
1852 /*
1853  * Get current search key.  For level 0 we don't actually have a key
1854  * structure so we make one up from the record.  For all other levels
1855  * we just return the right key.
1856  */
1857 STATIC union xfs_btree_key *
1858 xfs_lookup_get_search_key(
1859         struct xfs_btree_cur    *cur,
1860         int                     level,
1861         int                     keyno,
1862         struct xfs_btree_block  *block,
1863         union xfs_btree_key     *kp)
1864 {
1865         if (level == 0) {
1866                 cur->bc_ops->init_key_from_rec(kp,
1867                                 xfs_btree_rec_addr(cur, keyno, block));
1868                 return kp;
1869         }
1870
1871         return xfs_btree_key_addr(cur, keyno, block);
1872 }
1873
1874 /*
1875  * Lookup the record.  The cursor is made to point to it, based on dir.
1876  * stat is set to 0 if can't find any such record, 1 for success.
1877  */
1878 int                                     /* error */
1879 xfs_btree_lookup(
1880         struct xfs_btree_cur    *cur,   /* btree cursor */
1881         xfs_lookup_t            dir,    /* <=, ==, or >= */
1882         int                     *stat)  /* success/failure */
1883 {
1884         struct xfs_btree_block  *block; /* current btree block */
1885         int64_t                 diff;   /* difference for the current key */
1886         int                     error;  /* error return value */
1887         int                     keyno;  /* current key number */
1888         int                     level;  /* level in the btree */
1889         union xfs_btree_ptr     *pp;    /* ptr to btree block */
1890         union xfs_btree_ptr     ptr;    /* ptr to btree block */
1891
1892         XFS_BTREE_STATS_INC(cur, lookup);
1893
1894         /* No such thing as a zero-level tree. */
1895         if (XFS_IS_CORRUPT(cur->bc_mp, cur->bc_nlevels == 0))
1896                 return -EFSCORRUPTED;
1897
1898         block = NULL;
1899         keyno = 0;
1900
1901         /* initialise start pointer from cursor */
1902         cur->bc_ops->init_ptr_from_cur(cur, &ptr);
1903         pp = &ptr;
1904
1905         /*
1906          * Iterate over each level in the btree, starting at the root.
1907          * For each level above the leaves, find the key we need, based
1908          * on the lookup record, then follow the corresponding block
1909          * pointer down to the next level.
1910          */
1911         for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {
1912                 /* Get the block we need to do the lookup on. */
1913                 error = xfs_btree_lookup_get_block(cur, level, pp, &block);
1914                 if (error)
1915                         goto error0;
1916
1917                 if (diff == 0) {
1918                         /*
1919                          * If we already had a key match at a higher level, we
1920                          * know we need to use the first entry in this block.
1921                          */
1922                         keyno = 1;
1923                 } else {
1924                         /* Otherwise search this block. Do a binary search. */
1925
1926                         int     high;   /* high entry number */
1927                         int     low;    /* low entry number */
1928
1929                         /* Set low and high entry numbers, 1-based. */
1930                         low = 1;
1931                         high = xfs_btree_get_numrecs(block);
1932                         if (!high) {
1933                                 /* Block is empty, must be an empty leaf. */
1934                                 if (level != 0 || cur->bc_nlevels != 1) {
1935                                         XFS_CORRUPTION_ERROR(__func__,
1936                                                         XFS_ERRLEVEL_LOW,
1937                                                         cur->bc_mp, block,
1938                                                         sizeof(*block));
1939                                         return -EFSCORRUPTED;
1940                                 }
1941
1942                                 cur->bc_levels[0].ptr = dir != XFS_LOOKUP_LE;
1943                                 *stat = 0;
1944                                 return 0;
1945                         }
1946
1947                         /* Binary search the block. */
1948                         while (low <= high) {
1949                                 union xfs_btree_key     key;
1950                                 union xfs_btree_key     *kp;
1951
1952                                 XFS_BTREE_STATS_INC(cur, compare);
1953
1954                                 /* keyno is average of low and high. */
1955                                 keyno = (low + high) >> 1;
1956
1957                                 /* Get current search key */
1958                                 kp = xfs_lookup_get_search_key(cur, level,
1959                                                 keyno, block, &key);
1960
1961                                 /*
1962                                  * Compute difference to get next direction:
1963                                  *  - less than, move right
1964                                  *  - greater than, move left
1965                                  *  - equal, we're done
1966                                  */
1967                                 diff = cur->bc_ops->key_diff(cur, kp);
1968                                 if (diff < 0)
1969                                         low = keyno + 1;
1970                                 else if (diff > 0)
1971                                         high = keyno - 1;
1972                                 else
1973                                         break;
1974                         }
1975                 }
1976
1977                 /*
1978                  * If there are more levels, set up for the next level
1979                  * by getting the block number and filling in the cursor.
1980                  */
1981                 if (level > 0) {
1982                         /*
1983                          * If we moved left, need the previous key number,
1984                          * unless there isn't one.
1985                          */
1986                         if (diff > 0 && --keyno < 1)
1987                                 keyno = 1;
1988                         pp = xfs_btree_ptr_addr(cur, keyno, block);
1989
1990                         error = xfs_btree_debug_check_ptr(cur, pp, 0, level);
1991                         if (error)
1992                                 goto error0;
1993
1994                         cur->bc_levels[level].ptr = keyno;
1995                 }
1996         }
1997
1998         /* Done with the search. See if we need to adjust the results. */
1999         if (dir != XFS_LOOKUP_LE && diff < 0) {
2000                 keyno++;
2001                 /*
2002                  * If ge search and we went off the end of the block, but it's
2003                  * not the last block, we're in the wrong block.
2004                  */
2005                 xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
2006                 if (dir == XFS_LOOKUP_GE &&
2007                     keyno > xfs_btree_get_numrecs(block) &&
2008                     !xfs_btree_ptr_is_null(cur, &ptr)) {
2009                         int     i;
2010
2011                         cur->bc_levels[0].ptr = keyno;
2012                         error = xfs_btree_increment(cur, 0, &i);
2013                         if (error)
2014                                 goto error0;
2015                         if (XFS_IS_CORRUPT(cur->bc_mp, i != 1))
2016                                 return -EFSCORRUPTED;
2017                         *stat = 1;
2018                         return 0;
2019                 }
2020         } else if (dir == XFS_LOOKUP_LE && diff > 0)
2021                 keyno--;
2022         cur->bc_levels[0].ptr = keyno;
2023
2024         /* Return if we succeeded or not. */
2025         if (keyno == 0 || keyno > xfs_btree_get_numrecs(block))
2026                 *stat = 0;
2027         else if (dir != XFS_LOOKUP_EQ || diff == 0)
2028                 *stat = 1;
2029         else
2030                 *stat = 0;
2031         return 0;
2032
2033 error0:
2034         return error;
2035 }
2036
2037 /* Find the high key storage area from a regular key. */
2038 union xfs_btree_key *
2039 xfs_btree_high_key_from_key(
2040         struct xfs_btree_cur    *cur,
2041         union xfs_btree_key     *key)
2042 {
2043         ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
2044         return (union xfs_btree_key *)((char *)key +
2045                         (cur->bc_ops->key_len / 2));
2046 }
2047
2048 /* Determine the low (and high if overlapped) keys of a leaf block */
2049 STATIC void
2050 xfs_btree_get_leaf_keys(
2051         struct xfs_btree_cur    *cur,
2052         struct xfs_btree_block  *block,
2053         union xfs_btree_key     *key)
2054 {
2055         union xfs_btree_key     max_hkey;
2056         union xfs_btree_key     hkey;
2057         union xfs_btree_rec     *rec;
2058         union xfs_btree_key     *high;
2059         int                     n;
2060
2061         rec = xfs_btree_rec_addr(cur, 1, block);
2062         cur->bc_ops->init_key_from_rec(key, rec);
2063
2064         if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2065
2066                 cur->bc_ops->init_high_key_from_rec(&max_hkey, rec);
2067                 for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
2068                         rec = xfs_btree_rec_addr(cur, n, block);
2069                         cur->bc_ops->init_high_key_from_rec(&hkey, rec);
2070                         if (cur->bc_ops->diff_two_keys(cur, &hkey, &max_hkey)
2071                                         > 0)
2072                                 max_hkey = hkey;
2073                 }
2074
2075                 high = xfs_btree_high_key_from_key(cur, key);
2076                 memcpy(high, &max_hkey, cur->bc_ops->key_len / 2);
2077         }
2078 }
2079
2080 /* Determine the low (and high if overlapped) keys of a node block */
2081 STATIC void
2082 xfs_btree_get_node_keys(
2083         struct xfs_btree_cur    *cur,
2084         struct xfs_btree_block  *block,
2085         union xfs_btree_key     *key)
2086 {
2087         union xfs_btree_key     *hkey;
2088         union xfs_btree_key     *max_hkey;
2089         union xfs_btree_key     *high;
2090         int                     n;
2091
2092         if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2093                 memcpy(key, xfs_btree_key_addr(cur, 1, block),
2094                                 cur->bc_ops->key_len / 2);
2095
2096                 max_hkey = xfs_btree_high_key_addr(cur, 1, block);
2097                 for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
2098                         hkey = xfs_btree_high_key_addr(cur, n, block);
2099                         if (cur->bc_ops->diff_two_keys(cur, hkey, max_hkey) > 0)
2100                                 max_hkey = hkey;
2101                 }
2102
2103                 high = xfs_btree_high_key_from_key(cur, key);
2104                 memcpy(high, max_hkey, cur->bc_ops->key_len / 2);
2105         } else {
2106                 memcpy(key, xfs_btree_key_addr(cur, 1, block),
2107                                 cur->bc_ops->key_len);
2108         }
2109 }
2110
2111 /* Derive the keys for any btree block. */
2112 void
2113 xfs_btree_get_keys(
2114         struct xfs_btree_cur    *cur,
2115         struct xfs_btree_block  *block,
2116         union xfs_btree_key     *key)
2117 {
2118         if (be16_to_cpu(block->bb_level) == 0)
2119                 xfs_btree_get_leaf_keys(cur, block, key);
2120         else
2121                 xfs_btree_get_node_keys(cur, block, key);
2122 }
2123
2124 /*
2125  * Decide if we need to update the parent keys of a btree block.  For
2126  * a standard btree this is only necessary if we're updating the first
2127  * record/key.  For an overlapping btree, we must always update the
2128  * keys because the highest key can be in any of the records or keys
2129  * in the block.
2130  */
2131 static inline bool
2132 xfs_btree_needs_key_update(
2133         struct xfs_btree_cur    *cur,
2134         int                     ptr)
2135 {
2136         return (cur->bc_flags & XFS_BTREE_OVERLAPPING) || ptr == 1;
2137 }
2138
2139 /*
2140  * Update the low and high parent keys of the given level, progressing
2141  * towards the root.  If force_all is false, stop if the keys for a given
2142  * level do not need updating.
2143  */
2144 STATIC int
2145 __xfs_btree_updkeys(
2146         struct xfs_btree_cur    *cur,
2147         int                     level,
2148         struct xfs_btree_block  *block,
2149         struct xfs_buf          *bp0,
2150         bool                    force_all)
2151 {
2152         union xfs_btree_key     key;    /* keys from current level */
2153         union xfs_btree_key     *lkey;  /* keys from the next level up */
2154         union xfs_btree_key     *hkey;
2155         union xfs_btree_key     *nlkey; /* keys from the next level up */
2156         union xfs_btree_key     *nhkey;
2157         struct xfs_buf          *bp;
2158         int                     ptr;
2159
2160         ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
2161
2162         /* Exit if there aren't any parent levels to update. */
2163         if (level + 1 >= cur->bc_nlevels)
2164                 return 0;
2165
2166         trace_xfs_btree_updkeys(cur, level, bp0);
2167
2168         lkey = &key;
2169         hkey = xfs_btree_high_key_from_key(cur, lkey);
2170         xfs_btree_get_keys(cur, block, lkey);
2171         for (level++; level < cur->bc_nlevels; level++) {
2172 #ifdef DEBUG
2173                 int             error;
2174 #endif
2175                 block = xfs_btree_get_block(cur, level, &bp);
2176                 trace_xfs_btree_updkeys(cur, level, bp);
2177 #ifdef DEBUG
2178                 error = xfs_btree_check_block(cur, block, level, bp);
2179                 if (error)
2180                         return error;
2181 #endif
2182                 ptr = cur->bc_levels[level].ptr;
2183                 nlkey = xfs_btree_key_addr(cur, ptr, block);
2184                 nhkey = xfs_btree_high_key_addr(cur, ptr, block);
2185                 if (!force_all &&
2186                     !(cur->bc_ops->diff_two_keys(cur, nlkey, lkey) != 0 ||
2187                       cur->bc_ops->diff_two_keys(cur, nhkey, hkey) != 0))
2188                         break;
2189                 xfs_btree_copy_keys(cur, nlkey, lkey, 1);
2190                 xfs_btree_log_keys(cur, bp, ptr, ptr);
2191                 if (level + 1 >= cur->bc_nlevels)
2192                         break;
2193                 xfs_btree_get_node_keys(cur, block, lkey);
2194         }
2195
2196         return 0;
2197 }
2198
2199 /* Update all the keys from some level in cursor back to the root. */
2200 STATIC int
2201 xfs_btree_updkeys_force(
2202         struct xfs_btree_cur    *cur,
2203         int                     level)
2204 {
2205         struct xfs_buf          *bp;
2206         struct xfs_btree_block  *block;
2207
2208         block = xfs_btree_get_block(cur, level, &bp);
2209         return __xfs_btree_updkeys(cur, level, block, bp, true);
2210 }
2211
2212 /*
2213  * Update the parent keys of the given level, progressing towards the root.
2214  */
2215 STATIC int
2216 xfs_btree_update_keys(
2217         struct xfs_btree_cur    *cur,
2218         int                     level)
2219 {
2220         struct xfs_btree_block  *block;
2221         struct xfs_buf          *bp;
2222         union xfs_btree_key     *kp;
2223         union xfs_btree_key     key;
2224         int                     ptr;
2225
2226         ASSERT(level >= 0);
2227
2228         block = xfs_btree_get_block(cur, level, &bp);
2229         if (cur->bc_flags & XFS_BTREE_OVERLAPPING)
2230                 return __xfs_btree_updkeys(cur, level, block, bp, false);
2231
2232         /*
2233          * Go up the tree from this level toward the root.
2234          * At each level, update the key value to the value input.
2235          * Stop when we reach a level where the cursor isn't pointing
2236          * at the first entry in the block.
2237          */
2238         xfs_btree_get_keys(cur, block, &key);
2239         for (level++, ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
2240 #ifdef DEBUG
2241                 int             error;
2242 #endif
2243                 block = xfs_btree_get_block(cur, level, &bp);
2244 #ifdef DEBUG
2245                 error = xfs_btree_check_block(cur, block, level, bp);
2246                 if (error)
2247                         return error;
2248 #endif
2249                 ptr = cur->bc_levels[level].ptr;
2250                 kp = xfs_btree_key_addr(cur, ptr, block);
2251                 xfs_btree_copy_keys(cur, kp, &key, 1);
2252                 xfs_btree_log_keys(cur, bp, ptr, ptr);
2253         }
2254
2255         return 0;
2256 }
2257
2258 /*
2259  * Update the record referred to by cur to the value in the
2260  * given record. This either works (return 0) or gets an
2261  * EFSCORRUPTED error.
2262  */
2263 int
2264 xfs_btree_update(
2265         struct xfs_btree_cur    *cur,
2266         union xfs_btree_rec     *rec)
2267 {
2268         struct xfs_btree_block  *block;
2269         struct xfs_buf          *bp;
2270         int                     error;
2271         int                     ptr;
2272         union xfs_btree_rec     *rp;
2273
2274         /* Pick up the current block. */
2275         block = xfs_btree_get_block(cur, 0, &bp);
2276
2277 #ifdef DEBUG
2278         error = xfs_btree_check_block(cur, block, 0, bp);
2279         if (error)
2280                 goto error0;
2281 #endif
2282         /* Get the address of the rec to be updated. */
2283         ptr = cur->bc_levels[0].ptr;
2284         rp = xfs_btree_rec_addr(cur, ptr, block);
2285
2286         /* Fill in the new contents and log them. */
2287         xfs_btree_copy_recs(cur, rp, rec, 1);
2288         xfs_btree_log_recs(cur, bp, ptr, ptr);
2289
2290         /*
2291          * If we are tracking the last record in the tree and
2292          * we are at the far right edge of the tree, update it.
2293          */
2294         if (xfs_btree_is_lastrec(cur, block, 0)) {
2295                 cur->bc_ops->update_lastrec(cur, block, rec,
2296                                             ptr, LASTREC_UPDATE);
2297         }
2298
2299         /* Pass new key value up to our parent. */
2300         if (xfs_btree_needs_key_update(cur, ptr)) {
2301                 error = xfs_btree_update_keys(cur, 0);
2302                 if (error)
2303                         goto error0;
2304         }
2305
2306         return 0;
2307
2308 error0:
2309         return error;
2310 }
2311
2312 /*
2313  * Move 1 record left from cur/level if possible.
2314  * Update cur to reflect the new path.
2315  */
2316 STATIC int                                      /* error */
2317 xfs_btree_lshift(
2318         struct xfs_btree_cur    *cur,
2319         int                     level,
2320         int                     *stat)          /* success/failure */
2321 {
2322         struct xfs_buf          *lbp;           /* left buffer pointer */
2323         struct xfs_btree_block  *left;          /* left btree block */
2324         int                     lrecs;          /* left record count */
2325         struct xfs_buf          *rbp;           /* right buffer pointer */
2326         struct xfs_btree_block  *right;         /* right btree block */
2327         struct xfs_btree_cur    *tcur;          /* temporary btree cursor */
2328         int                     rrecs;          /* right record count */
2329         union xfs_btree_ptr     lptr;           /* left btree pointer */
2330         union xfs_btree_key     *rkp = NULL;    /* right btree key */
2331         union xfs_btree_ptr     *rpp = NULL;    /* right address pointer */
2332         union xfs_btree_rec     *rrp = NULL;    /* right record pointer */
2333         int                     error;          /* error return value */
2334         int                     i;
2335
2336         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2337             level == cur->bc_nlevels - 1)
2338                 goto out0;
2339
2340         /* Set up variables for this block as "right". */
2341         right = xfs_btree_get_block(cur, level, &rbp);
2342
2343 #ifdef DEBUG
2344         error = xfs_btree_check_block(cur, right, level, rbp);
2345         if (error)
2346                 goto error0;
2347 #endif
2348
2349         /* If we've got no left sibling then we can't shift an entry left. */
2350         xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2351         if (xfs_btree_ptr_is_null(cur, &lptr))
2352                 goto out0;
2353
2354         /*
2355          * If the cursor entry is the one that would be moved, don't
2356          * do it... it's too complicated.
2357          */
2358         if (cur->bc_levels[level].ptr <= 1)
2359                 goto out0;
2360
2361         /* Set up the left neighbor as "left". */
2362         error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
2363         if (error)
2364                 goto error0;
2365
2366         /* If it's full, it can't take another entry. */
2367         lrecs = xfs_btree_get_numrecs(left);
2368         if (lrecs == cur->bc_ops->get_maxrecs(cur, level))
2369                 goto out0;
2370
2371         rrecs = xfs_btree_get_numrecs(right);
2372
2373         /*
2374          * We add one entry to the left side and remove one for the right side.
2375          * Account for it here, the changes will be updated on disk and logged
2376          * later.
2377          */
2378         lrecs++;
2379         rrecs--;
2380
2381         XFS_BTREE_STATS_INC(cur, lshift);
2382         XFS_BTREE_STATS_ADD(cur, moves, 1);
2383
2384         /*
2385          * If non-leaf, copy a key and a ptr to the left block.
2386          * Log the changes to the left block.
2387          */
2388         if (level > 0) {
2389                 /* It's a non-leaf.  Move keys and pointers. */
2390                 union xfs_btree_key     *lkp;   /* left btree key */
2391                 union xfs_btree_ptr     *lpp;   /* left address pointer */
2392
2393                 lkp = xfs_btree_key_addr(cur, lrecs, left);
2394                 rkp = xfs_btree_key_addr(cur, 1, right);
2395
2396                 lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2397                 rpp = xfs_btree_ptr_addr(cur, 1, right);
2398
2399                 error = xfs_btree_debug_check_ptr(cur, rpp, 0, level);
2400                 if (error)
2401                         goto error0;
2402
2403                 xfs_btree_copy_keys(cur, lkp, rkp, 1);
2404                 xfs_btree_copy_ptrs(cur, lpp, rpp, 1);
2405
2406                 xfs_btree_log_keys(cur, lbp, lrecs, lrecs);
2407                 xfs_btree_log_ptrs(cur, lbp, lrecs, lrecs);
2408
2409                 ASSERT(cur->bc_ops->keys_inorder(cur,
2410                         xfs_btree_key_addr(cur, lrecs - 1, left), lkp));
2411         } else {
2412                 /* It's a leaf.  Move records.  */
2413                 union xfs_btree_rec     *lrp;   /* left record pointer */
2414
2415                 lrp = xfs_btree_rec_addr(cur, lrecs, left);
2416                 rrp = xfs_btree_rec_addr(cur, 1, right);
2417
2418                 xfs_btree_copy_recs(cur, lrp, rrp, 1);
2419                 xfs_btree_log_recs(cur, lbp, lrecs, lrecs);
2420
2421                 ASSERT(cur->bc_ops->recs_inorder(cur,
2422                         xfs_btree_rec_addr(cur, lrecs - 1, left), lrp));
2423         }
2424
2425         xfs_btree_set_numrecs(left, lrecs);
2426         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2427
2428         xfs_btree_set_numrecs(right, rrecs);
2429         xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2430
2431         /*
2432          * Slide the contents of right down one entry.
2433          */
2434         XFS_BTREE_STATS_ADD(cur, moves, rrecs - 1);
2435         if (level > 0) {
2436                 /* It's a nonleaf. operate on keys and ptrs */
2437                 for (i = 0; i < rrecs; i++) {
2438                         error = xfs_btree_debug_check_ptr(cur, rpp, i + 1, level);
2439                         if (error)
2440                                 goto error0;
2441                 }
2442
2443                 xfs_btree_shift_keys(cur,
2444                                 xfs_btree_key_addr(cur, 2, right),
2445                                 -1, rrecs);
2446                 xfs_btree_shift_ptrs(cur,
2447                                 xfs_btree_ptr_addr(cur, 2, right),
2448                                 -1, rrecs);
2449
2450                 xfs_btree_log_keys(cur, rbp, 1, rrecs);
2451                 xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2452         } else {
2453                 /* It's a leaf. operate on records */
2454                 xfs_btree_shift_recs(cur,
2455                         xfs_btree_rec_addr(cur, 2, right),
2456                         -1, rrecs);
2457                 xfs_btree_log_recs(cur, rbp, 1, rrecs);
2458         }
2459
2460         /*
2461          * Using a temporary cursor, update the parent key values of the
2462          * block on the left.
2463          */
2464         if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2465                 error = xfs_btree_dup_cursor(cur, &tcur);
2466                 if (error)
2467                         goto error0;
2468                 i = xfs_btree_firstrec(tcur, level);
2469                 if (XFS_IS_CORRUPT(tcur->bc_mp, i != 1)) {
2470                         error = -EFSCORRUPTED;
2471                         goto error0;
2472                 }
2473
2474                 error = xfs_btree_decrement(tcur, level, &i);
2475                 if (error)
2476                         goto error1;
2477
2478                 /* Update the parent high keys of the left block, if needed. */
2479                 error = xfs_btree_update_keys(tcur, level);
2480                 if (error)
2481                         goto error1;
2482
2483                 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2484         }
2485
2486         /* Update the parent keys of the right block. */
2487         error = xfs_btree_update_keys(cur, level);
2488         if (error)
2489                 goto error0;
2490
2491         /* Slide the cursor value left one. */
2492         cur->bc_levels[level].ptr--;
2493
2494         *stat = 1;
2495         return 0;
2496
2497 out0:
2498         *stat = 0;
2499         return 0;
2500
2501 error0:
2502         return error;
2503
2504 error1:
2505         xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2506         return error;
2507 }
2508
2509 /*
2510  * Move 1 record right from cur/level if possible.
2511  * Update cur to reflect the new path.
2512  */
2513 STATIC int                                      /* error */
2514 xfs_btree_rshift(
2515         struct xfs_btree_cur    *cur,
2516         int                     level,
2517         int                     *stat)          /* success/failure */
2518 {
2519         struct xfs_buf          *lbp;           /* left buffer pointer */
2520         struct xfs_btree_block  *left;          /* left btree block */
2521         struct xfs_buf          *rbp;           /* right buffer pointer */
2522         struct xfs_btree_block  *right;         /* right btree block */
2523         struct xfs_btree_cur    *tcur;          /* temporary btree cursor */
2524         union xfs_btree_ptr     rptr;           /* right block pointer */
2525         union xfs_btree_key     *rkp;           /* right btree key */
2526         int                     rrecs;          /* right record count */
2527         int                     lrecs;          /* left record count */
2528         int                     error;          /* error return value */
2529         int                     i;              /* loop counter */
2530
2531         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2532             (level == cur->bc_nlevels - 1))
2533                 goto out0;
2534
2535         /* Set up variables for this block as "left". */
2536         left = xfs_btree_get_block(cur, level, &lbp);
2537
2538 #ifdef DEBUG
2539         error = xfs_btree_check_block(cur, left, level, lbp);
2540         if (error)
2541                 goto error0;
2542 #endif
2543
2544         /* If we've got no right sibling then we can't shift an entry right. */
2545         xfs_btree_get_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2546         if (xfs_btree_ptr_is_null(cur, &rptr))
2547                 goto out0;
2548
2549         /*
2550          * If the cursor entry is the one that would be moved, don't
2551          * do it... it's too complicated.
2552          */
2553         lrecs = xfs_btree_get_numrecs(left);
2554         if (cur->bc_levels[level].ptr >= lrecs)
2555                 goto out0;
2556
2557         /* Set up the right neighbor as "right". */
2558         error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
2559         if (error)
2560                 goto error0;
2561
2562         /* If it's full, it can't take another entry. */
2563         rrecs = xfs_btree_get_numrecs(right);
2564         if (rrecs == cur->bc_ops->get_maxrecs(cur, level))
2565                 goto out0;
2566
2567         XFS_BTREE_STATS_INC(cur, rshift);
2568         XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2569
2570         /*
2571          * Make a hole at the start of the right neighbor block, then
2572          * copy the last left block entry to the hole.
2573          */
2574         if (level > 0) {
2575                 /* It's a nonleaf. make a hole in the keys and ptrs */
2576                 union xfs_btree_key     *lkp;
2577                 union xfs_btree_ptr     *lpp;
2578                 union xfs_btree_ptr     *rpp;
2579
2580                 lkp = xfs_btree_key_addr(cur, lrecs, left);
2581                 lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2582                 rkp = xfs_btree_key_addr(cur, 1, right);
2583                 rpp = xfs_btree_ptr_addr(cur, 1, right);
2584
2585                 for (i = rrecs - 1; i >= 0; i--) {
2586                         error = xfs_btree_debug_check_ptr(cur, rpp, i, level);
2587                         if (error)
2588                                 goto error0;
2589                 }
2590
2591                 xfs_btree_shift_keys(cur, rkp, 1, rrecs);
2592                 xfs_btree_shift_ptrs(cur, rpp, 1, rrecs);
2593
2594                 error = xfs_btree_debug_check_ptr(cur, lpp, 0, level);
2595                 if (error)
2596                         goto error0;
2597
2598                 /* Now put the new data in, and log it. */
2599                 xfs_btree_copy_keys(cur, rkp, lkp, 1);
2600                 xfs_btree_copy_ptrs(cur, rpp, lpp, 1);
2601
2602                 xfs_btree_log_keys(cur, rbp, 1, rrecs + 1);
2603                 xfs_btree_log_ptrs(cur, rbp, 1, rrecs + 1);
2604
2605                 ASSERT(cur->bc_ops->keys_inorder(cur, rkp,
2606                         xfs_btree_key_addr(cur, 2, right)));
2607         } else {
2608                 /* It's a leaf. make a hole in the records */
2609                 union xfs_btree_rec     *lrp;
2610                 union xfs_btree_rec     *rrp;
2611
2612                 lrp = xfs_btree_rec_addr(cur, lrecs, left);
2613                 rrp = xfs_btree_rec_addr(cur, 1, right);
2614
2615                 xfs_btree_shift_recs(cur, rrp, 1, rrecs);
2616
2617                 /* Now put the new data in, and log it. */
2618                 xfs_btree_copy_recs(cur, rrp, lrp, 1);
2619                 xfs_btree_log_recs(cur, rbp, 1, rrecs + 1);
2620         }
2621
2622         /*
2623          * Decrement and log left's numrecs, bump and log right's numrecs.
2624          */
2625         xfs_btree_set_numrecs(left, --lrecs);
2626         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2627
2628         xfs_btree_set_numrecs(right, ++rrecs);
2629         xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2630
2631         /*
2632          * Using a temporary cursor, update the parent key values of the
2633          * block on the right.
2634          */
2635         error = xfs_btree_dup_cursor(cur, &tcur);
2636         if (error)
2637                 goto error0;
2638         i = xfs_btree_lastrec(tcur, level);
2639         if (XFS_IS_CORRUPT(tcur->bc_mp, i != 1)) {
2640                 error = -EFSCORRUPTED;
2641                 goto error0;
2642         }
2643
2644         error = xfs_btree_increment(tcur, level, &i);
2645         if (error)
2646                 goto error1;
2647
2648         /* Update the parent high keys of the left block, if needed. */
2649         if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2650                 error = xfs_btree_update_keys(cur, level);
2651                 if (error)
2652                         goto error1;
2653         }
2654
2655         /* Update the parent keys of the right block. */
2656         error = xfs_btree_update_keys(tcur, level);
2657         if (error)
2658                 goto error1;
2659
2660         xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2661
2662         *stat = 1;
2663         return 0;
2664
2665 out0:
2666         *stat = 0;
2667         return 0;
2668
2669 error0:
2670         return error;
2671
2672 error1:
2673         xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2674         return error;
2675 }
2676
2677 /*
2678  * Split cur/level block in half.
2679  * Return new block number and the key to its first
2680  * record (to be inserted into parent).
2681  */
2682 STATIC int                                      /* error */
2683 __xfs_btree_split(
2684         struct xfs_btree_cur    *cur,
2685         int                     level,
2686         union xfs_btree_ptr     *ptrp,
2687         union xfs_btree_key     *key,
2688         struct xfs_btree_cur    **curp,
2689         int                     *stat)          /* success/failure */
2690 {
2691         union xfs_btree_ptr     lptr;           /* left sibling block ptr */
2692         struct xfs_buf          *lbp;           /* left buffer pointer */
2693         struct xfs_btree_block  *left;          /* left btree block */
2694         union xfs_btree_ptr     rptr;           /* right sibling block ptr */
2695         struct xfs_buf          *rbp;           /* right buffer pointer */
2696         struct xfs_btree_block  *right;         /* right btree block */
2697         union xfs_btree_ptr     rrptr;          /* right-right sibling ptr */
2698         struct xfs_buf          *rrbp;          /* right-right buffer pointer */
2699         struct xfs_btree_block  *rrblock;       /* right-right btree block */
2700         int                     lrecs;
2701         int                     rrecs;
2702         int                     src_index;
2703         int                     error;          /* error return value */
2704         int                     i;
2705
2706         XFS_BTREE_STATS_INC(cur, split);
2707
2708         /* Set up left block (current one). */
2709         left = xfs_btree_get_block(cur, level, &lbp);
2710
2711 #ifdef DEBUG
2712         error = xfs_btree_check_block(cur, left, level, lbp);
2713         if (error)
2714                 goto error0;
2715 #endif
2716
2717         xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2718
2719         /* Allocate the new block. If we can't do it, we're toast. Give up. */
2720         error = cur->bc_ops->alloc_block(cur, &lptr, &rptr, stat);
2721         if (error)
2722                 goto error0;
2723         if (*stat == 0)
2724                 goto out0;
2725         XFS_BTREE_STATS_INC(cur, alloc);
2726
2727         /* Set up the new block as "right". */
2728         error = xfs_btree_get_buf_block(cur, &rptr, &right, &rbp);
2729         if (error)
2730                 goto error0;
2731
2732         /* Fill in the btree header for the new right block. */
2733         xfs_btree_init_block_cur(cur, rbp, xfs_btree_get_level(left), 0);
2734
2735         /*
2736          * Split the entries between the old and the new block evenly.
2737          * Make sure that if there's an odd number of entries now, that
2738          * each new block will have the same number of entries.
2739          */
2740         lrecs = xfs_btree_get_numrecs(left);
2741         rrecs = lrecs / 2;
2742         if ((lrecs & 1) && cur->bc_levels[level].ptr <= rrecs + 1)
2743                 rrecs++;
2744         src_index = (lrecs - rrecs + 1);
2745
2746         XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2747
2748         /* Adjust numrecs for the later get_*_keys() calls. */
2749         lrecs -= rrecs;
2750         xfs_btree_set_numrecs(left, lrecs);
2751         xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
2752
2753         /*
2754          * Copy btree block entries from the left block over to the
2755          * new block, the right. Update the right block and log the
2756          * changes.
2757          */
2758         if (level > 0) {
2759                 /* It's a non-leaf.  Move keys and pointers. */
2760                 union xfs_btree_key     *lkp;   /* left btree key */
2761                 union xfs_btree_ptr     *lpp;   /* left address pointer */
2762                 union xfs_btree_key     *rkp;   /* right btree key */
2763                 union xfs_btree_ptr     *rpp;   /* right address pointer */
2764
2765                 lkp = xfs_btree_key_addr(cur, src_index, left);
2766                 lpp = xfs_btree_ptr_addr(cur, src_index, left);
2767                 rkp = xfs_btree_key_addr(cur, 1, right);
2768                 rpp = xfs_btree_ptr_addr(cur, 1, right);
2769
2770                 for (i = src_index; i < rrecs; i++) {
2771                         error = xfs_btree_debug_check_ptr(cur, lpp, i, level);
2772                         if (error)
2773                                 goto error0;
2774                 }
2775
2776                 /* Copy the keys & pointers to the new block. */
2777                 xfs_btree_copy_keys(cur, rkp, lkp, rrecs);
2778                 xfs_btree_copy_ptrs(cur, rpp, lpp, rrecs);
2779
2780                 xfs_btree_log_keys(cur, rbp, 1, rrecs);
2781                 xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2782
2783                 /* Stash the keys of the new block for later insertion. */
2784                 xfs_btree_get_node_keys(cur, right, key);
2785         } else {
2786                 /* It's a leaf.  Move records.  */
2787                 union xfs_btree_rec     *lrp;   /* left record pointer */
2788                 union xfs_btree_rec     *rrp;   /* right record pointer */
2789
2790                 lrp = xfs_btree_rec_addr(cur, src_index, left);
2791                 rrp = xfs_btree_rec_addr(cur, 1, right);
2792
2793                 /* Copy records to the new block. */
2794                 xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
2795                 xfs_btree_log_recs(cur, rbp, 1, rrecs);
2796
2797                 /* Stash the keys of the new block for later insertion. */
2798                 xfs_btree_get_leaf_keys(cur, right, key);
2799         }
2800
2801         /*
2802          * Find the left block number by looking in the buffer.
2803          * Adjust sibling pointers.
2804          */
2805         xfs_btree_get_sibling(cur, left, &rrptr, XFS_BB_RIGHTSIB);
2806         xfs_btree_set_sibling(cur, right, &rrptr, XFS_BB_RIGHTSIB);
2807         xfs_btree_set_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2808         xfs_btree_set_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2809
2810         xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
2811         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
2812
2813         /*
2814          * If there's a block to the new block's right, make that block
2815          * point back to right instead of to left.
2816          */
2817         if (!xfs_btree_ptr_is_null(cur, &rrptr)) {
2818                 error = xfs_btree_read_buf_block(cur, &rrptr,
2819                                                         0, &rrblock, &rrbp);
2820                 if (error)
2821                         goto error0;
2822                 xfs_btree_set_sibling(cur, rrblock, &rptr, XFS_BB_LEFTSIB);
2823                 xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
2824         }
2825
2826         /* Update the parent high keys of the left block, if needed. */
2827         if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2828                 error = xfs_btree_update_keys(cur, level);
2829                 if (error)
2830                         goto error0;
2831         }
2832
2833         /*
2834          * If the cursor is really in the right block, move it there.
2835          * If it's just pointing past the last entry in left, then we'll
2836          * insert there, so don't change anything in that case.
2837          */
2838         if (cur->bc_levels[level].ptr > lrecs + 1) {
2839                 xfs_btree_setbuf(cur, level, rbp);
2840                 cur->bc_levels[level].ptr -= lrecs;
2841         }
2842         /*
2843          * If there are more levels, we'll need another cursor which refers
2844          * the right block, no matter where this cursor was.
2845          */
2846         if (level + 1 < cur->bc_nlevels) {
2847                 error = xfs_btree_dup_cursor(cur, curp);
2848                 if (error)
2849                         goto error0;
2850                 (*curp)->bc_levels[level + 1].ptr++;
2851         }
2852         *ptrp = rptr;
2853         *stat = 1;
2854         return 0;
2855 out0:
2856         *stat = 0;
2857         return 0;
2858
2859 error0:
2860         return error;
2861 }
2862
2863 #ifdef __KERNEL__
2864 struct xfs_btree_split_args {
2865         struct xfs_btree_cur    *cur;
2866         int                     level;
2867         union xfs_btree_ptr     *ptrp;
2868         union xfs_btree_key     *key;
2869         struct xfs_btree_cur    **curp;
2870         int                     *stat;          /* success/failure */
2871         int                     result;
2872         bool                    kswapd; /* allocation in kswapd context */
2873         struct completion       *done;
2874         struct work_struct      work;
2875 };
2876
2877 /*
2878  * Stack switching interfaces for allocation
2879  */
2880 static void
2881 xfs_btree_split_worker(
2882         struct work_struct      *work)
2883 {
2884         struct xfs_btree_split_args     *args = container_of(work,
2885                                                 struct xfs_btree_split_args, work);
2886         unsigned long           pflags;
2887         unsigned long           new_pflags = 0;
2888
2889         /*
2890          * we are in a transaction context here, but may also be doing work
2891          * in kswapd context, and hence we may need to inherit that state
2892          * temporarily to ensure that we don't block waiting for memory reclaim
2893          * in any way.
2894          */
2895         if (args->kswapd)
2896                 new_pflags |= PF_MEMALLOC | PF_KSWAPD;
2897
2898         current_set_flags_nested(&pflags, new_pflags);
2899         xfs_trans_set_context(args->cur->bc_tp);
2900
2901         args->result = __xfs_btree_split(args->cur, args->level, args->ptrp,
2902                                          args->key, args->curp, args->stat);
2903
2904         xfs_trans_clear_context(args->cur->bc_tp);
2905         current_restore_flags_nested(&pflags, new_pflags);
2906
2907         /*
2908          * Do not access args after complete() has run here. We don't own args
2909          * and the owner may run and free args before we return here.
2910          */
2911         complete(args->done);
2912
2913 }
2914
2915 /*
2916  * BMBT split requests often come in with little stack to work on. Push
2917  * them off to a worker thread so there is lots of stack to use. For the other
2918  * btree types, just call directly to avoid the context switch overhead here.
2919  */
2920 STATIC int                                      /* error */
2921 xfs_btree_split(
2922         struct xfs_btree_cur    *cur,
2923         int                     level,
2924         union xfs_btree_ptr     *ptrp,
2925         union xfs_btree_key     *key,
2926         struct xfs_btree_cur    **curp,
2927         int                     *stat)          /* success/failure */
2928 {
2929         struct xfs_btree_split_args     args;
2930         DECLARE_COMPLETION_ONSTACK(done);
2931
2932         if (cur->bc_btnum != XFS_BTNUM_BMAP)
2933                 return __xfs_btree_split(cur, level, ptrp, key, curp, stat);
2934
2935         args.cur = cur;
2936         args.level = level;
2937         args.ptrp = ptrp;
2938         args.key = key;
2939         args.curp = curp;
2940         args.stat = stat;
2941         args.done = &done;
2942         args.kswapd = current_is_kswapd();
2943         INIT_WORK_ONSTACK(&args.work, xfs_btree_split_worker);
2944         queue_work(xfs_alloc_wq, &args.work);
2945         wait_for_completion(&done);
2946         destroy_work_on_stack(&args.work);
2947         return args.result;
2948 }
2949 #else
2950 #define xfs_btree_split __xfs_btree_split
2951 #endif /* __KERNEL__ */
2952
2953
2954 /*
2955  * Copy the old inode root contents into a real block and make the
2956  * broot point to it.
2957  */
2958 int                                             /* error */
2959 xfs_btree_new_iroot(
2960         struct xfs_btree_cur    *cur,           /* btree cursor */
2961         int                     *logflags,      /* logging flags for inode */
2962         int                     *stat)          /* return status - 0 fail */
2963 {
2964         struct xfs_buf          *cbp;           /* buffer for cblock */
2965         struct xfs_btree_block  *block;         /* btree block */
2966         struct xfs_btree_block  *cblock;        /* child btree block */
2967         union xfs_btree_key     *ckp;           /* child key pointer */
2968         union xfs_btree_ptr     *cpp;           /* child ptr pointer */
2969         union xfs_btree_key     *kp;            /* pointer to btree key */
2970         union xfs_btree_ptr     *pp;            /* pointer to block addr */
2971         union xfs_btree_ptr     nptr;           /* new block addr */
2972         int                     level;          /* btree level */
2973         int                     error;          /* error return code */
2974         int                     i;              /* loop counter */
2975
2976         XFS_BTREE_STATS_INC(cur, newroot);
2977
2978         ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
2979
2980         level = cur->bc_nlevels - 1;
2981
2982         block = xfs_btree_get_iroot(cur);
2983         pp = xfs_btree_ptr_addr(cur, 1, block);
2984
2985         /* Allocate the new block. If we can't do it, we're toast. Give up. */
2986         error = cur->bc_ops->alloc_block(cur, pp, &nptr, stat);
2987         if (error)
2988                 goto error0;
2989         if (*stat == 0)
2990                 return 0;
2991
2992         XFS_BTREE_STATS_INC(cur, alloc);
2993
2994         /* Copy the root into a real block. */
2995         error = xfs_btree_get_buf_block(cur, &nptr, &cblock, &cbp);
2996         if (error)
2997                 goto error0;
2998
2999         /*
3000          * we can't just memcpy() the root in for CRC enabled btree blocks.
3001          * In that case have to also ensure the blkno remains correct
3002          */
3003         memcpy(cblock, block, xfs_btree_block_len(cur));
3004         if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS) {
3005                 __be64 bno = cpu_to_be64(xfs_buf_daddr(cbp));
3006                 if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
3007                         cblock->bb_u.l.bb_blkno = bno;
3008                 else
3009                         cblock->bb_u.s.bb_blkno = bno;
3010         }
3011
3012         be16_add_cpu(&block->bb_level, 1);
3013         xfs_btree_set_numrecs(block, 1);
3014         cur->bc_nlevels++;
3015         ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
3016         cur->bc_levels[level + 1].ptr = 1;
3017
3018         kp = xfs_btree_key_addr(cur, 1, block);
3019         ckp = xfs_btree_key_addr(cur, 1, cblock);
3020         xfs_btree_copy_keys(cur, ckp, kp, xfs_btree_get_numrecs(cblock));
3021
3022         cpp = xfs_btree_ptr_addr(cur, 1, cblock);
3023         for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
3024                 error = xfs_btree_debug_check_ptr(cur, pp, i, level);
3025                 if (error)
3026                         goto error0;
3027         }
3028
3029         xfs_btree_copy_ptrs(cur, cpp, pp, xfs_btree_get_numrecs(cblock));
3030
3031         error = xfs_btree_debug_check_ptr(cur, &nptr, 0, level);
3032         if (error)
3033                 goto error0;
3034
3035         xfs_btree_copy_ptrs(cur, pp, &nptr, 1);
3036
3037         xfs_iroot_realloc(cur->bc_ino.ip,
3038                           1 - xfs_btree_get_numrecs(cblock),
3039                           cur->bc_ino.whichfork);
3040
3041         xfs_btree_setbuf(cur, level, cbp);
3042
3043         /*
3044          * Do all this logging at the end so that
3045          * the root is at the right level.
3046          */
3047         xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
3048         xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
3049         xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
3050
3051         *logflags |=
3052                 XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_ino.whichfork);
3053         *stat = 1;
3054         return 0;
3055 error0:
3056         return error;
3057 }
3058
3059 /*
3060  * Allocate a new root block, fill it in.
3061  */
3062 STATIC int                              /* error */
3063 xfs_btree_new_root(
3064         struct xfs_btree_cur    *cur,   /* btree cursor */
3065         int                     *stat)  /* success/failure */
3066 {
3067         struct xfs_btree_block  *block; /* one half of the old root block */
3068         struct xfs_buf          *bp;    /* buffer containing block */
3069         int                     error;  /* error return value */
3070         struct xfs_buf          *lbp;   /* left buffer pointer */
3071         struct xfs_btree_block  *left;  /* left btree block */
3072         struct xfs_buf          *nbp;   /* new (root) buffer */
3073         struct xfs_btree_block  *new;   /* new (root) btree block */
3074         int                     nptr;   /* new value for key index, 1 or 2 */
3075         struct xfs_buf          *rbp;   /* right buffer pointer */
3076         struct xfs_btree_block  *right; /* right btree block */
3077         union xfs_btree_ptr     rptr;
3078         union xfs_btree_ptr     lptr;
3079
3080         XFS_BTREE_STATS_INC(cur, newroot);
3081
3082         /* initialise our start point from the cursor */
3083         cur->bc_ops->init_ptr_from_cur(cur, &rptr);
3084
3085         /* Allocate the new block. If we can't do it, we're toast. Give up. */
3086         error = cur->bc_ops->alloc_block(cur, &rptr, &lptr, stat);
3087         if (error)
3088                 goto error0;
3089         if (*stat == 0)
3090                 goto out0;
3091         XFS_BTREE_STATS_INC(cur, alloc);
3092
3093         /* Set up the new block. */
3094         error = xfs_btree_get_buf_block(cur, &lptr, &new, &nbp);
3095         if (error)
3096                 goto error0;
3097
3098         /* Set the root in the holding structure  increasing the level by 1. */
3099         cur->bc_ops->set_root(cur, &lptr, 1);
3100
3101         /*
3102          * At the previous root level there are now two blocks: the old root,
3103          * and the new block generated when it was split.  We don't know which
3104          * one the cursor is pointing at, so we set up variables "left" and
3105          * "right" for each case.
3106          */
3107         block = xfs_btree_get_block(cur, cur->bc_nlevels - 1, &bp);
3108
3109 #ifdef DEBUG
3110         error = xfs_btree_check_block(cur, block, cur->bc_nlevels - 1, bp);
3111         if (error)
3112                 goto error0;
3113 #endif
3114
3115         xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3116         if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3117                 /* Our block is left, pick up the right block. */
3118                 lbp = bp;
3119                 xfs_btree_buf_to_ptr(cur, lbp, &lptr);
3120                 left = block;
3121                 error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
3122                 if (error)
3123                         goto error0;
3124                 bp = rbp;
3125                 nptr = 1;
3126         } else {
3127                 /* Our block is right, pick up the left block. */
3128                 rbp = bp;
3129                 xfs_btree_buf_to_ptr(cur, rbp, &rptr);
3130                 right = block;
3131                 xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
3132                 error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
3133                 if (error)
3134                         goto error0;
3135                 bp = lbp;
3136                 nptr = 2;
3137         }
3138
3139         /* Fill in the new block's btree header and log it. */
3140         xfs_btree_init_block_cur(cur, nbp, cur->bc_nlevels, 2);
3141         xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
3142         ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
3143                         !xfs_btree_ptr_is_null(cur, &rptr));
3144
3145         /* Fill in the key data in the new root. */
3146         if (xfs_btree_get_level(left) > 0) {
3147                 /*
3148                  * Get the keys for the left block's keys and put them directly
3149                  * in the parent block.  Do the same for the right block.
3150                  */
3151                 xfs_btree_get_node_keys(cur, left,
3152                                 xfs_btree_key_addr(cur, 1, new));
3153                 xfs_btree_get_node_keys(cur, right,
3154                                 xfs_btree_key_addr(cur, 2, new));
3155         } else {
3156                 /*
3157                  * Get the keys for the left block's records and put them
3158                  * directly in the parent block.  Do the same for the right
3159                  * block.
3160                  */
3161                 xfs_btree_get_leaf_keys(cur, left,
3162                         xfs_btree_key_addr(cur, 1, new));
3163                 xfs_btree_get_leaf_keys(cur, right,
3164                         xfs_btree_key_addr(cur, 2, new));
3165         }
3166         xfs_btree_log_keys(cur, nbp, 1, 2);
3167
3168         /* Fill in the pointer data in the new root. */
3169         xfs_btree_copy_ptrs(cur,
3170                 xfs_btree_ptr_addr(cur, 1, new), &lptr, 1);
3171         xfs_btree_copy_ptrs(cur,
3172                 xfs_btree_ptr_addr(cur, 2, new), &rptr, 1);
3173         xfs_btree_log_ptrs(cur, nbp, 1, 2);
3174
3175         /* Fix up the cursor. */
3176         xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
3177         cur->bc_levels[cur->bc_nlevels].ptr = nptr;
3178         cur->bc_nlevels++;
3179         ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
3180         *stat = 1;
3181         return 0;
3182 error0:
3183         return error;
3184 out0:
3185         *stat = 0;
3186         return 0;
3187 }
3188
3189 STATIC int
3190 xfs_btree_make_block_unfull(
3191         struct xfs_btree_cur    *cur,   /* btree cursor */
3192         int                     level,  /* btree level */
3193         int                     numrecs,/* # of recs in block */
3194         int                     *oindex,/* old tree index */
3195         int                     *index, /* new tree index */
3196         union xfs_btree_ptr     *nptr,  /* new btree ptr */
3197         struct xfs_btree_cur    **ncur, /* new btree cursor */
3198         union xfs_btree_key     *key,   /* key of new block */
3199         int                     *stat)
3200 {
3201         int                     error = 0;
3202
3203         if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
3204             level == cur->bc_nlevels - 1) {
3205                 struct xfs_inode *ip = cur->bc_ino.ip;
3206
3207                 if (numrecs < cur->bc_ops->get_dmaxrecs(cur, level)) {
3208                         /* A root block that can be made bigger. */
3209                         xfs_iroot_realloc(ip, 1, cur->bc_ino.whichfork);
3210                         *stat = 1;
3211                 } else {
3212                         /* A root block that needs replacing */
3213                         int     logflags = 0;
3214
3215                         error = xfs_btree_new_iroot(cur, &logflags, stat);
3216                         if (error || *stat == 0)
3217                                 return error;
3218
3219                         xfs_trans_log_inode(cur->bc_tp, ip, logflags);
3220                 }
3221
3222                 return 0;
3223         }
3224
3225         /* First, try shifting an entry to the right neighbor. */
3226         error = xfs_btree_rshift(cur, level, stat);
3227         if (error || *stat)
3228                 return error;
3229
3230         /* Next, try shifting an entry to the left neighbor. */
3231         error = xfs_btree_lshift(cur, level, stat);
3232         if (error)
3233                 return error;
3234
3235         if (*stat) {
3236                 *oindex = *index = cur->bc_levels[level].ptr;
3237                 return 0;
3238         }
3239
3240         /*
3241          * Next, try splitting the current block in half.
3242          *
3243          * If this works we have to re-set our variables because we
3244          * could be in a different block now.
3245          */
3246         error = xfs_btree_split(cur, level, nptr, key, ncur, stat);
3247         if (error || *stat == 0)
3248                 return error;
3249
3250
3251         *index = cur->bc_levels[level].ptr;
3252         return 0;
3253 }
3254
3255 /*
3256  * Insert one record/level.  Return information to the caller
3257  * allowing the next level up to proceed if necessary.
3258  */
3259 STATIC int
3260 xfs_btree_insrec(
3261         struct xfs_btree_cur    *cur,   /* btree cursor */
3262         int                     level,  /* level to insert record at */
3263         union xfs_btree_ptr     *ptrp,  /* i/o: block number inserted */
3264         union xfs_btree_rec     *rec,   /* record to insert */
3265         union xfs_btree_key     *key,   /* i/o: block key for ptrp */
3266         struct xfs_btree_cur    **curp, /* output: new cursor replacing cur */
3267         int                     *stat)  /* success/failure */
3268 {
3269         struct xfs_btree_block  *block; /* btree block */
3270         struct xfs_buf          *bp;    /* buffer for block */
3271         union xfs_btree_ptr     nptr;   /* new block ptr */
3272         struct xfs_btree_cur    *ncur = NULL;   /* new btree cursor */
3273         union xfs_btree_key     nkey;   /* new block key */
3274         union xfs_btree_key     *lkey;
3275         int                     optr;   /* old key/record index */
3276         int                     ptr;    /* key/record index */
3277         int                     numrecs;/* number of records */
3278         int                     error;  /* error return value */
3279         int                     i;
3280         xfs_daddr_t             old_bn;
3281
3282         ncur = NULL;
3283         lkey = &nkey;
3284
3285         /*
3286          * If we have an external root pointer, and we've made it to the
3287          * root level, allocate a new root block and we're done.
3288          */
3289         if (!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
3290             (level >= cur->bc_nlevels)) {
3291                 error = xfs_btree_new_root(cur, stat);
3292                 xfs_btree_set_ptr_null(cur, ptrp);
3293
3294                 return error;
3295         }
3296
3297         /* If we're off the left edge, return failure. */
3298         ptr = cur->bc_levels[level].ptr;
3299         if (ptr == 0) {
3300                 *stat = 0;
3301                 return 0;
3302         }
3303
3304         optr = ptr;
3305
3306         XFS_BTREE_STATS_INC(cur, insrec);
3307
3308         /* Get pointers to the btree buffer and block. */
3309         block = xfs_btree_get_block(cur, level, &bp);
3310         old_bn = bp ? xfs_buf_daddr(bp) : XFS_BUF_DADDR_NULL;
3311         numrecs = xfs_btree_get_numrecs(block);
3312
3313 #ifdef DEBUG
3314         error = xfs_btree_check_block(cur, block, level, bp);
3315         if (error)
3316                 goto error0;
3317
3318         /* Check that the new entry is being inserted in the right place. */
3319         if (ptr <= numrecs) {
3320                 if (level == 0) {
3321                         ASSERT(cur->bc_ops->recs_inorder(cur, rec,
3322                                 xfs_btree_rec_addr(cur, ptr, block)));
3323                 } else {
3324                         ASSERT(cur->bc_ops->keys_inorder(cur, key,
3325                                 xfs_btree_key_addr(cur, ptr, block)));
3326                 }
3327         }
3328 #endif
3329
3330         /*
3331          * If the block is full, we can't insert the new entry until we
3332          * make the block un-full.
3333          */
3334         xfs_btree_set_ptr_null(cur, &nptr);
3335         if (numrecs == cur->bc_ops->get_maxrecs(cur, level)) {
3336                 error = xfs_btree_make_block_unfull(cur, level, numrecs,
3337                                         &optr, &ptr, &nptr, &ncur, lkey, stat);
3338                 if (error || *stat == 0)
3339                         goto error0;
3340         }
3341
3342         /*
3343          * The current block may have changed if the block was
3344          * previously full and we have just made space in it.
3345          */
3346         block = xfs_btree_get_block(cur, level, &bp);
3347         numrecs = xfs_btree_get_numrecs(block);
3348
3349 #ifdef DEBUG
3350         error = xfs_btree_check_block(cur, block, level, bp);
3351         if (error)
3352                 goto error0;
3353 #endif
3354
3355         /*
3356          * At this point we know there's room for our new entry in the block
3357          * we're pointing at.
3358          */
3359         XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr + 1);
3360
3361         if (level > 0) {
3362                 /* It's a nonleaf. make a hole in the keys and ptrs */
3363                 union xfs_btree_key     *kp;
3364                 union xfs_btree_ptr     *pp;
3365
3366                 kp = xfs_btree_key_addr(cur, ptr, block);
3367                 pp = xfs_btree_ptr_addr(cur, ptr, block);
3368
3369                 for (i = numrecs - ptr; i >= 0; i--) {
3370                         error = xfs_btree_debug_check_ptr(cur, pp, i, level);
3371                         if (error)
3372                                 goto error0;
3373                 }
3374
3375                 xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1);
3376                 xfs_btree_shift_ptrs(cur, pp, 1, numrecs - ptr + 1);
3377
3378                 error = xfs_btree_debug_check_ptr(cur, ptrp, 0, level);
3379                 if (error)
3380                         goto error0;
3381
3382                 /* Now put the new data in, bump numrecs and log it. */
3383                 xfs_btree_copy_keys(cur, kp, key, 1);
3384                 xfs_btree_copy_ptrs(cur, pp, ptrp, 1);
3385                 numrecs++;
3386                 xfs_btree_set_numrecs(block, numrecs);
3387                 xfs_btree_log_ptrs(cur, bp, ptr, numrecs);
3388                 xfs_btree_log_keys(cur, bp, ptr, numrecs);
3389 #ifdef DEBUG
3390                 if (ptr < numrecs) {
3391                         ASSERT(cur->bc_ops->keys_inorder(cur, kp,
3392                                 xfs_btree_key_addr(cur, ptr + 1, block)));
3393                 }
3394 #endif
3395         } else {
3396                 /* It's a leaf. make a hole in the records */
3397                 union xfs_btree_rec             *rp;
3398
3399                 rp = xfs_btree_rec_addr(cur, ptr, block);
3400
3401                 xfs_btree_shift_recs(cur, rp, 1, numrecs - ptr + 1);
3402
3403                 /* Now put the new data in, bump numrecs and log it. */
3404                 xfs_btree_copy_recs(cur, rp, rec, 1);
3405                 xfs_btree_set_numrecs(block, ++numrecs);
3406                 xfs_btree_log_recs(cur, bp, ptr, numrecs);
3407 #ifdef DEBUG
3408                 if (ptr < numrecs) {
3409                         ASSERT(cur->bc_ops->recs_inorder(cur, rp,
3410                                 xfs_btree_rec_addr(cur, ptr + 1, block)));
3411                 }
3412 #endif
3413         }
3414
3415         /* Log the new number of records in the btree header. */
3416         xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3417
3418         /*
3419          * If we just inserted into a new tree block, we have to
3420          * recalculate nkey here because nkey is out of date.
3421          *
3422          * Otherwise we're just updating an existing block (having shoved
3423          * some records into the new tree block), so use the regular key
3424          * update mechanism.
3425          */
3426         if (bp && xfs_buf_daddr(bp) != old_bn) {
3427                 xfs_btree_get_keys(cur, block, lkey);
3428         } else if (xfs_btree_needs_key_update(cur, optr)) {
3429                 error = xfs_btree_update_keys(cur, level);
3430                 if (error)
3431                         goto error0;
3432         }
3433
3434         /*
3435          * If we are tracking the last record in the tree and
3436          * we are at the far right edge of the tree, update it.
3437          */
3438         if (xfs_btree_is_lastrec(cur, block, level)) {
3439                 cur->bc_ops->update_lastrec(cur, block, rec,
3440                                             ptr, LASTREC_INSREC);
3441         }
3442
3443         /*
3444          * Return the new block number, if any.
3445          * If there is one, give back a record value and a cursor too.
3446          */
3447         *ptrp = nptr;
3448         if (!xfs_btree_ptr_is_null(cur, &nptr)) {
3449                 xfs_btree_copy_keys(cur, key, lkey, 1);
3450                 *curp = ncur;
3451         }
3452
3453         *stat = 1;
3454         return 0;
3455
3456 error0:
3457         if (ncur)
3458                 xfs_btree_del_cursor(ncur, error);
3459         return error;
3460 }
3461
3462 /*
3463  * Insert the record at the point referenced by cur.
3464  *
3465  * A multi-level split of the tree on insert will invalidate the original
3466  * cursor.  All callers of this function should assume that the cursor is
3467  * no longer valid and revalidate it.
3468  */
3469 int
3470 xfs_btree_insert(
3471         struct xfs_btree_cur    *cur,
3472         int                     *stat)
3473 {
3474         int                     error;  /* error return value */
3475         int                     i;      /* result value, 0 for failure */
3476         int                     level;  /* current level number in btree */
3477         union xfs_btree_ptr     nptr;   /* new block number (split result) */
3478         struct xfs_btree_cur    *ncur;  /* new cursor (split result) */
3479         struct xfs_btree_cur    *pcur;  /* previous level's cursor */
3480         union xfs_btree_key     bkey;   /* key of block to insert */
3481         union xfs_btree_key     *key;
3482         union xfs_btree_rec     rec;    /* record to insert */
3483
3484         level = 0;
3485         ncur = NULL;
3486         pcur = cur;
3487         key = &bkey;
3488
3489         xfs_btree_set_ptr_null(cur, &nptr);
3490
3491         /* Make a key out of the record data to be inserted, and save it. */
3492         cur->bc_ops->init_rec_from_cur(cur, &rec);
3493         cur->bc_ops->init_key_from_rec(key, &rec);
3494
3495         /*
3496          * Loop going up the tree, starting at the leaf level.
3497          * Stop when we don't get a split block, that must mean that
3498          * the insert is finished with this level.
3499          */
3500         do {
3501                 /*
3502                  * Insert nrec/nptr into this level of the tree.
3503                  * Note if we fail, nptr will be null.
3504                  */
3505                 error = xfs_btree_insrec(pcur, level, &nptr, &rec, key,
3506                                 &ncur, &i);
3507                 if (error) {
3508                         if (pcur != cur)
3509                                 xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
3510                         goto error0;
3511                 }
3512
3513                 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3514                         error = -EFSCORRUPTED;
3515                         goto error0;
3516                 }
3517                 level++;
3518
3519                 /*
3520                  * See if the cursor we just used is trash.
3521                  * Can't trash the caller's cursor, but otherwise we should
3522                  * if ncur is a new cursor or we're about to be done.
3523                  */
3524                 if (pcur != cur &&
3525                     (ncur || xfs_btree_ptr_is_null(cur, &nptr))) {
3526                         /* Save the state from the cursor before we trash it */
3527                         if (cur->bc_ops->update_cursor)
3528                                 cur->bc_ops->update_cursor(pcur, cur);
3529                         cur->bc_nlevels = pcur->bc_nlevels;
3530                         xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
3531                 }
3532                 /* If we got a new cursor, switch to it. */
3533                 if (ncur) {
3534                         pcur = ncur;
3535                         ncur = NULL;
3536                 }
3537         } while (!xfs_btree_ptr_is_null(cur, &nptr));
3538
3539         *stat = i;
3540         return 0;
3541 error0:
3542         return error;
3543 }
3544
3545 /*
3546  * Try to merge a non-leaf block back into the inode root.
3547  *
3548  * Note: the killroot names comes from the fact that we're effectively
3549  * killing the old root block.  But because we can't just delete the
3550  * inode we have to copy the single block it was pointing to into the
3551  * inode.
3552  */
3553 STATIC int
3554 xfs_btree_kill_iroot(
3555         struct xfs_btree_cur    *cur)
3556 {
3557         int                     whichfork = cur->bc_ino.whichfork;
3558         struct xfs_inode        *ip = cur->bc_ino.ip;
3559         struct xfs_ifork        *ifp = xfs_ifork_ptr(ip, whichfork);
3560         struct xfs_btree_block  *block;
3561         struct xfs_btree_block  *cblock;
3562         union xfs_btree_key     *kp;
3563         union xfs_btree_key     *ckp;
3564         union xfs_btree_ptr     *pp;
3565         union xfs_btree_ptr     *cpp;
3566         struct xfs_buf          *cbp;
3567         int                     level;
3568         int                     index;
3569         int                     numrecs;
3570         int                     error;
3571 #ifdef DEBUG
3572         union xfs_btree_ptr     ptr;
3573 #endif
3574         int                     i;
3575
3576         ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
3577         ASSERT(cur->bc_nlevels > 1);
3578
3579         /*
3580          * Don't deal with the root block needs to be a leaf case.
3581          * We're just going to turn the thing back into extents anyway.
3582          */
3583         level = cur->bc_nlevels - 1;
3584         if (level == 1)
3585                 goto out0;
3586
3587         /*
3588          * Give up if the root has multiple children.
3589          */
3590         block = xfs_btree_get_iroot(cur);
3591         if (xfs_btree_get_numrecs(block) != 1)
3592                 goto out0;
3593
3594         cblock = xfs_btree_get_block(cur, level - 1, &cbp);
3595         numrecs = xfs_btree_get_numrecs(cblock);
3596
3597         /*
3598          * Only do this if the next level will fit.
3599          * Then the data must be copied up to the inode,
3600          * instead of freeing the root you free the next level.
3601          */
3602         if (numrecs > cur->bc_ops->get_dmaxrecs(cur, level))
3603                 goto out0;
3604
3605         XFS_BTREE_STATS_INC(cur, killroot);
3606
3607 #ifdef DEBUG
3608         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
3609         ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3610         xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
3611         ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3612 #endif
3613
3614         index = numrecs - cur->bc_ops->get_maxrecs(cur, level);
3615         if (index) {
3616                 xfs_iroot_realloc(cur->bc_ino.ip, index,
3617                                   cur->bc_ino.whichfork);
3618                 block = ifp->if_broot;
3619         }
3620
3621         be16_add_cpu(&block->bb_numrecs, index);
3622         ASSERT(block->bb_numrecs == cblock->bb_numrecs);
3623
3624         kp = xfs_btree_key_addr(cur, 1, block);
3625         ckp = xfs_btree_key_addr(cur, 1, cblock);
3626         xfs_btree_copy_keys(cur, kp, ckp, numrecs);
3627
3628         pp = xfs_btree_ptr_addr(cur, 1, block);
3629         cpp = xfs_btree_ptr_addr(cur, 1, cblock);
3630
3631         for (i = 0; i < numrecs; i++) {
3632                 error = xfs_btree_debug_check_ptr(cur, cpp, i, level - 1);
3633                 if (error)
3634                         return error;
3635         }
3636
3637         xfs_btree_copy_ptrs(cur, pp, cpp, numrecs);
3638
3639         error = xfs_btree_free_block(cur, cbp);
3640         if (error)
3641                 return error;
3642
3643         cur->bc_levels[level - 1].bp = NULL;
3644         be16_add_cpu(&block->bb_level, -1);
3645         xfs_trans_log_inode(cur->bc_tp, ip,
3646                 XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_ino.whichfork));
3647         cur->bc_nlevels--;
3648 out0:
3649         return 0;
3650 }
3651
3652 /*
3653  * Kill the current root node, and replace it with it's only child node.
3654  */
3655 STATIC int
3656 xfs_btree_kill_root(
3657         struct xfs_btree_cur    *cur,
3658         struct xfs_buf          *bp,
3659         int                     level,
3660         union xfs_btree_ptr     *newroot)
3661 {
3662         int                     error;
3663
3664         XFS_BTREE_STATS_INC(cur, killroot);
3665
3666         /*
3667          * Update the root pointer, decreasing the level by 1 and then
3668          * free the old root.
3669          */
3670         cur->bc_ops->set_root(cur, newroot, -1);
3671
3672         error = xfs_btree_free_block(cur, bp);
3673         if (error)
3674                 return error;
3675
3676         cur->bc_levels[level].bp = NULL;
3677         cur->bc_levels[level].ra = 0;
3678         cur->bc_nlevels--;
3679
3680         return 0;
3681 }
3682
3683 STATIC int
3684 xfs_btree_dec_cursor(
3685         struct xfs_btree_cur    *cur,
3686         int                     level,
3687         int                     *stat)
3688 {
3689         int                     error;
3690         int                     i;
3691
3692         if (level > 0) {
3693                 error = xfs_btree_decrement(cur, level, &i);
3694                 if (error)
3695                         return error;
3696         }
3697
3698         *stat = 1;
3699         return 0;
3700 }
3701
3702 /*
3703  * Single level of the btree record deletion routine.
3704  * Delete record pointed to by cur/level.
3705  * Remove the record from its block then rebalance the tree.
3706  * Return 0 for error, 1 for done, 2 to go on to the next level.
3707  */
3708 STATIC int                                      /* error */
3709 xfs_btree_delrec(
3710         struct xfs_btree_cur    *cur,           /* btree cursor */
3711         int                     level,          /* level removing record from */
3712         int                     *stat)          /* fail/done/go-on */
3713 {
3714         struct xfs_btree_block  *block;         /* btree block */
3715         union xfs_btree_ptr     cptr;           /* current block ptr */
3716         struct xfs_buf          *bp;            /* buffer for block */
3717         int                     error;          /* error return value */
3718         int                     i;              /* loop counter */
3719         union xfs_btree_ptr     lptr;           /* left sibling block ptr */
3720         struct xfs_buf          *lbp;           /* left buffer pointer */
3721         struct xfs_btree_block  *left;          /* left btree block */
3722         int                     lrecs = 0;      /* left record count */
3723         int                     ptr;            /* key/record index */
3724         union xfs_btree_ptr     rptr;           /* right sibling block ptr */
3725         struct xfs_buf          *rbp;           /* right buffer pointer */
3726         struct xfs_btree_block  *right;         /* right btree block */
3727         struct xfs_btree_block  *rrblock;       /* right-right btree block */
3728         struct xfs_buf          *rrbp;          /* right-right buffer pointer */
3729         int                     rrecs = 0;      /* right record count */
3730         struct xfs_btree_cur    *tcur;          /* temporary btree cursor */
3731         int                     numrecs;        /* temporary numrec count */
3732
3733         tcur = NULL;
3734
3735         /* Get the index of the entry being deleted, check for nothing there. */
3736         ptr = cur->bc_levels[level].ptr;
3737         if (ptr == 0) {
3738                 *stat = 0;
3739                 return 0;
3740         }
3741
3742         /* Get the buffer & block containing the record or key/ptr. */
3743         block = xfs_btree_get_block(cur, level, &bp);
3744         numrecs = xfs_btree_get_numrecs(block);
3745
3746 #ifdef DEBUG
3747         error = xfs_btree_check_block(cur, block, level, bp);
3748         if (error)
3749                 goto error0;
3750 #endif
3751
3752         /* Fail if we're off the end of the block. */
3753         if (ptr > numrecs) {
3754                 *stat = 0;
3755                 return 0;
3756         }
3757
3758         XFS_BTREE_STATS_INC(cur, delrec);
3759         XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr);
3760
3761         /* Excise the entries being deleted. */
3762         if (level > 0) {
3763                 /* It's a nonleaf. operate on keys and ptrs */
3764                 union xfs_btree_key     *lkp;
3765                 union xfs_btree_ptr     *lpp;
3766
3767                 lkp = xfs_btree_key_addr(cur, ptr + 1, block);
3768                 lpp = xfs_btree_ptr_addr(cur, ptr + 1, block);
3769
3770                 for (i = 0; i < numrecs - ptr; i++) {
3771                         error = xfs_btree_debug_check_ptr(cur, lpp, i, level);
3772                         if (error)
3773                                 goto error0;
3774                 }
3775
3776                 if (ptr < numrecs) {
3777                         xfs_btree_shift_keys(cur, lkp, -1, numrecs - ptr);
3778                         xfs_btree_shift_ptrs(cur, lpp, -1, numrecs - ptr);
3779                         xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
3780                         xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
3781                 }
3782         } else {
3783                 /* It's a leaf. operate on records */
3784                 if (ptr < numrecs) {
3785                         xfs_btree_shift_recs(cur,
3786                                 xfs_btree_rec_addr(cur, ptr + 1, block),
3787                                 -1, numrecs - ptr);
3788                         xfs_btree_log_recs(cur, bp, ptr, numrecs - 1);
3789                 }
3790         }
3791
3792         /*
3793          * Decrement and log the number of entries in the block.
3794          */
3795         xfs_btree_set_numrecs(block, --numrecs);
3796         xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3797
3798         /*
3799          * If we are tracking the last record in the tree and
3800          * we are at the far right edge of the tree, update it.
3801          */
3802         if (xfs_btree_is_lastrec(cur, block, level)) {
3803                 cur->bc_ops->update_lastrec(cur, block, NULL,
3804                                             ptr, LASTREC_DELREC);
3805         }
3806
3807         /*
3808          * We're at the root level.  First, shrink the root block in-memory.
3809          * Try to get rid of the next level down.  If we can't then there's
3810          * nothing left to do.
3811          */
3812         if (level == cur->bc_nlevels - 1) {
3813                 if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3814                         xfs_iroot_realloc(cur->bc_ino.ip, -1,
3815                                           cur->bc_ino.whichfork);
3816
3817                         error = xfs_btree_kill_iroot(cur);
3818                         if (error)
3819                                 goto error0;
3820
3821                         error = xfs_btree_dec_cursor(cur, level, stat);
3822                         if (error)
3823                                 goto error0;
3824                         *stat = 1;
3825                         return 0;
3826                 }
3827
3828                 /*
3829                  * If this is the root level, and there's only one entry left,
3830                  * and it's NOT the leaf level, then we can get rid of this
3831                  * level.
3832                  */
3833                 if (numrecs == 1 && level > 0) {
3834                         union xfs_btree_ptr     *pp;
3835                         /*
3836                          * pp is still set to the first pointer in the block.
3837                          * Make it the new root of the btree.
3838                          */
3839                         pp = xfs_btree_ptr_addr(cur, 1, block);
3840                         error = xfs_btree_kill_root(cur, bp, level, pp);
3841                         if (error)
3842                                 goto error0;
3843                 } else if (level > 0) {
3844                         error = xfs_btree_dec_cursor(cur, level, stat);
3845                         if (error)
3846                                 goto error0;
3847                 }
3848                 *stat = 1;
3849                 return 0;
3850         }
3851
3852         /*
3853          * If we deleted the leftmost entry in the block, update the
3854          * key values above us in the tree.
3855          */
3856         if (xfs_btree_needs_key_update(cur, ptr)) {
3857                 error = xfs_btree_update_keys(cur, level);
3858                 if (error)
3859                         goto error0;
3860         }
3861
3862         /*
3863          * If the number of records remaining in the block is at least
3864          * the minimum, we're done.
3865          */
3866         if (numrecs >= cur->bc_ops->get_minrecs(cur, level)) {
3867                 error = xfs_btree_dec_cursor(cur, level, stat);
3868                 if (error)
3869                         goto error0;
3870                 return 0;
3871         }
3872
3873         /*
3874          * Otherwise, we have to move some records around to keep the
3875          * tree balanced.  Look at the left and right sibling blocks to
3876          * see if we can re-balance by moving only one record.
3877          */
3878         xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3879         xfs_btree_get_sibling(cur, block, &lptr, XFS_BB_LEFTSIB);
3880
3881         if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3882                 /*
3883                  * One child of root, need to get a chance to copy its contents
3884                  * into the root and delete it. Can't go up to next level,
3885                  * there's nothing to delete there.
3886                  */
3887                 if (xfs_btree_ptr_is_null(cur, &rptr) &&
3888                     xfs_btree_ptr_is_null(cur, &lptr) &&
3889                     level == cur->bc_nlevels - 2) {
3890                         error = xfs_btree_kill_iroot(cur);
3891                         if (!error)
3892                                 error = xfs_btree_dec_cursor(cur, level, stat);
3893                         if (error)
3894                                 goto error0;
3895                         return 0;
3896                 }
3897         }
3898
3899         ASSERT(!xfs_btree_ptr_is_null(cur, &rptr) ||
3900                !xfs_btree_ptr_is_null(cur, &lptr));
3901
3902         /*
3903          * Duplicate the cursor so our btree manipulations here won't
3904          * disrupt the next level up.
3905          */
3906         error = xfs_btree_dup_cursor(cur, &tcur);
3907         if (error)
3908                 goto error0;
3909
3910         /*
3911          * If there's a right sibling, see if it's ok to shift an entry
3912          * out of it.
3913          */
3914         if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3915                 /*
3916                  * Move the temp cursor to the last entry in the next block.
3917                  * Actually any entry but the first would suffice.
3918                  */
3919                 i = xfs_btree_lastrec(tcur, level);
3920                 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3921                         error = -EFSCORRUPTED;
3922                         goto error0;
3923                 }
3924
3925                 error = xfs_btree_increment(tcur, level, &i);
3926                 if (error)
3927                         goto error0;
3928                 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3929                         error = -EFSCORRUPTED;
3930                         goto error0;
3931                 }
3932
3933                 i = xfs_btree_lastrec(tcur, level);
3934                 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3935                         error = -EFSCORRUPTED;
3936                         goto error0;
3937                 }
3938
3939                 /* Grab a pointer to the block. */
3940                 right = xfs_btree_get_block(tcur, level, &rbp);
3941 #ifdef DEBUG
3942                 error = xfs_btree_check_block(tcur, right, level, rbp);
3943                 if (error)
3944                         goto error0;
3945 #endif
3946                 /* Grab the current block number, for future use. */
3947                 xfs_btree_get_sibling(tcur, right, &cptr, XFS_BB_LEFTSIB);
3948
3949                 /*
3950                  * If right block is full enough so that removing one entry
3951                  * won't make it too empty, and left-shifting an entry out
3952                  * of right to us works, we're done.
3953                  */
3954                 if (xfs_btree_get_numrecs(right) - 1 >=
3955                     cur->bc_ops->get_minrecs(tcur, level)) {
3956                         error = xfs_btree_lshift(tcur, level, &i);
3957                         if (error)
3958                                 goto error0;
3959                         if (i) {
3960                                 ASSERT(xfs_btree_get_numrecs(block) >=
3961                                        cur->bc_ops->get_minrecs(tcur, level));
3962
3963                                 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3964                                 tcur = NULL;
3965
3966                                 error = xfs_btree_dec_cursor(cur, level, stat);
3967                                 if (error)
3968                                         goto error0;
3969                                 return 0;
3970                         }
3971                 }
3972
3973                 /*
3974                  * Otherwise, grab the number of records in right for
3975                  * future reference, and fix up the temp cursor to point
3976                  * to our block again (last record).
3977                  */
3978                 rrecs = xfs_btree_get_numrecs(right);
3979                 if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3980                         i = xfs_btree_firstrec(tcur, level);
3981                         if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3982                                 error = -EFSCORRUPTED;
3983                                 goto error0;
3984                         }
3985
3986                         error = xfs_btree_decrement(tcur, level, &i);
3987                         if (error)
3988                                 goto error0;
3989                         if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3990                                 error = -EFSCORRUPTED;
3991                                 goto error0;
3992                         }
3993                 }
3994         }
3995
3996         /*
3997          * If there's a left sibling, see if it's ok to shift an entry
3998          * out of it.
3999          */
4000         if (!xfs_btree_ptr_is_null(cur, &lptr)) {
4001                 /*
4002                  * Move the temp cursor to the first entry in the
4003                  * previous block.
4004                  */
4005                 i = xfs_btree_firstrec(tcur, level);
4006                 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4007                         error = -EFSCORRUPTED;
4008                         goto error0;
4009                 }
4010
4011                 error = xfs_btree_decrement(tcur, level, &i);
4012                 if (error)
4013                         goto error0;
4014                 i = xfs_btree_firstrec(tcur, level);
4015                 if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4016                         error = -EFSCORRUPTED;
4017                         goto error0;
4018                 }
4019
4020                 /* Grab a pointer to the block. */
4021                 left = xfs_btree_get_block(tcur, level, &lbp);
4022 #ifdef DEBUG
4023                 error = xfs_btree_check_block(cur, left, level, lbp);
4024                 if (error)
4025                         goto error0;
4026 #endif
4027                 /* Grab the current block number, for future use. */
4028                 xfs_btree_get_sibling(tcur, left, &cptr, XFS_BB_RIGHTSIB);
4029
4030                 /*
4031                  * If left block is full enough so that removing one entry
4032                  * won't make it too empty, and right-shifting an entry out
4033                  * of left to us works, we're done.
4034                  */
4035                 if (xfs_btree_get_numrecs(left) - 1 >=
4036                     cur->bc_ops->get_minrecs(tcur, level)) {
4037                         error = xfs_btree_rshift(tcur, level, &i);
4038                         if (error)
4039                                 goto error0;
4040                         if (i) {
4041                                 ASSERT(xfs_btree_get_numrecs(block) >=
4042                                        cur->bc_ops->get_minrecs(tcur, level));
4043                                 xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
4044                                 tcur = NULL;
4045                                 if (level == 0)
4046                                         cur->bc_levels[0].ptr++;
4047
4048                                 *stat = 1;
4049                                 return 0;
4050                         }
4051                 }
4052
4053                 /*
4054                  * Otherwise, grab the number of records in right for
4055                  * future reference.
4056                  */
4057                 lrecs = xfs_btree_get_numrecs(left);
4058         }
4059
4060         /* Delete the temp cursor, we're done with it. */
4061         xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
4062         tcur = NULL;
4063
4064         /* If here, we need to do a join to keep the tree balanced. */
4065         ASSERT(!xfs_btree_ptr_is_null(cur, &cptr));
4066
4067         if (!xfs_btree_ptr_is_null(cur, &lptr) &&
4068             lrecs + xfs_btree_get_numrecs(block) <=
4069                         cur->bc_ops->get_maxrecs(cur, level)) {
4070                 /*
4071                  * Set "right" to be the starting block,
4072                  * "left" to be the left neighbor.
4073                  */
4074                 rptr = cptr;
4075                 right = block;
4076                 rbp = bp;
4077                 error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
4078                 if (error)
4079                         goto error0;
4080
4081         /*
4082          * If that won't work, see if we can join with the right neighbor block.
4083          */
4084         } else if (!xfs_btree_ptr_is_null(cur, &rptr) &&
4085                    rrecs + xfs_btree_get_numrecs(block) <=
4086                         cur->bc_ops->get_maxrecs(cur, level)) {
4087                 /*
4088                  * Set "left" to be the starting block,
4089                  * "right" to be the right neighbor.
4090                  */
4091                 lptr = cptr;
4092                 left = block;
4093                 lbp = bp;
4094                 error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
4095                 if (error)
4096                         goto error0;
4097
4098         /*
4099          * Otherwise, we can't fix the imbalance.
4100          * Just return.  This is probably a logic error, but it's not fatal.
4101          */
4102         } else {
4103                 error = xfs_btree_dec_cursor(cur, level, stat);
4104                 if (error)
4105                         goto error0;
4106                 return 0;
4107         }
4108
4109         rrecs = xfs_btree_get_numrecs(right);
4110         lrecs = xfs_btree_get_numrecs(left);
4111
4112         /*
4113          * We're now going to join "left" and "right" by moving all the stuff
4114          * in "right" to "left" and deleting "right".
4115          */
4116         XFS_BTREE_STATS_ADD(cur, moves, rrecs);
4117         if (level > 0) {
4118                 /* It's a non-leaf.  Move keys and pointers. */
4119                 union xfs_btree_key     *lkp;   /* left btree key */
4120                 union xfs_btree_ptr     *lpp;   /* left address pointer */
4121                 union xfs_btree_key     *rkp;   /* right btree key */
4122                 union xfs_btree_ptr     *rpp;   /* right address pointer */
4123
4124                 lkp = xfs_btree_key_addr(cur, lrecs + 1, left);
4125                 lpp = xfs_btree_ptr_addr(cur, lrecs + 1, left);
4126                 rkp = xfs_btree_key_addr(cur, 1, right);
4127                 rpp = xfs_btree_ptr_addr(cur, 1, right);
4128
4129                 for (i = 1; i < rrecs; i++) {
4130                         error = xfs_btree_debug_check_ptr(cur, rpp, i, level);
4131                         if (error)
4132                                 goto error0;
4133                 }
4134
4135                 xfs_btree_copy_keys(cur, lkp, rkp, rrecs);
4136                 xfs_btree_copy_ptrs(cur, lpp, rpp, rrecs);
4137
4138                 xfs_btree_log_keys(cur, lbp, lrecs + 1, lrecs + rrecs);
4139                 xfs_btree_log_ptrs(cur, lbp, lrecs + 1, lrecs + rrecs);
4140         } else {
4141                 /* It's a leaf.  Move records.  */
4142                 union xfs_btree_rec     *lrp;   /* left record pointer */
4143                 union xfs_btree_rec     *rrp;   /* right record pointer */
4144
4145                 lrp = xfs_btree_rec_addr(cur, lrecs + 1, left);
4146                 rrp = xfs_btree_rec_addr(cur, 1, right);
4147
4148                 xfs_btree_copy_recs(cur, lrp, rrp, rrecs);
4149                 xfs_btree_log_recs(cur, lbp, lrecs + 1, lrecs + rrecs);
4150         }
4151
4152         XFS_BTREE_STATS_INC(cur, join);
4153
4154         /*
4155          * Fix up the number of records and right block pointer in the
4156          * surviving block, and log it.
4157          */
4158         xfs_btree_set_numrecs(left, lrecs + rrecs);
4159         xfs_btree_get_sibling(cur, right, &cptr, XFS_BB_RIGHTSIB);
4160         xfs_btree_set_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
4161         xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
4162
4163         /* If there is a right sibling, point it to the remaining block. */
4164         xfs_btree_get_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
4165         if (!xfs_btree_ptr_is_null(cur, &cptr)) {
4166                 error = xfs_btree_read_buf_block(cur, &cptr, 0, &rrblock, &rrbp);
4167                 if (error)
4168                         goto error0;
4169                 xfs_btree_set_sibling(cur, rrblock, &lptr, XFS_BB_LEFTSIB);
4170                 xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
4171         }
4172
4173         /* Free the deleted block. */
4174         error = xfs_btree_free_block(cur, rbp);
4175         if (error)
4176                 goto error0;
4177
4178         /*
4179          * If we joined with the left neighbor, set the buffer in the
4180          * cursor to the left block, and fix up the index.
4181          */
4182         if (bp != lbp) {
4183                 cur->bc_levels[level].bp = lbp;
4184                 cur->bc_levels[level].ptr += lrecs;
4185                 cur->bc_levels[level].ra = 0;
4186         }
4187         /*
4188          * If we joined with the right neighbor and there's a level above
4189          * us, increment the cursor at that level.
4190          */
4191         else if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) ||
4192                    (level + 1 < cur->bc_nlevels)) {
4193                 error = xfs_btree_increment(cur, level + 1, &i);
4194                 if (error)
4195                         goto error0;
4196         }
4197
4198         /*
4199          * Readjust the ptr at this level if it's not a leaf, since it's
4200          * still pointing at the deletion point, which makes the cursor
4201          * inconsistent.  If this makes the ptr 0, the caller fixes it up.
4202          * We can't use decrement because it would change the next level up.
4203          */
4204         if (level > 0)
4205                 cur->bc_levels[level].ptr--;
4206
4207         /*
4208          * We combined blocks, so we have to update the parent keys if the
4209          * btree supports overlapped intervals.  However,
4210          * bc_levels[level + 1].ptr points to the old block so that the caller
4211          * knows which record to delete.  Therefore, the caller must be savvy
4212          * enough to call updkeys for us if we return stat == 2.  The other
4213          * exit points from this function don't require deletions further up
4214          * the tree, so they can call updkeys directly.
4215          */
4216
4217         /* Return value means the next level up has something to do. */
4218         *stat = 2;
4219         return 0;
4220
4221 error0:
4222         if (tcur)
4223                 xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
4224         return error;
4225 }
4226
4227 /*
4228  * Delete the record pointed to by cur.
4229  * The cursor refers to the place where the record was (could be inserted)
4230  * when the operation returns.
4231  */
4232 int                                     /* error */
4233 xfs_btree_delete(
4234         struct xfs_btree_cur    *cur,
4235         int                     *stat)  /* success/failure */
4236 {
4237         int                     error;  /* error return value */
4238         int                     level;
4239         int                     i;
4240         bool                    joined = false;
4241
4242         /*
4243          * Go up the tree, starting at leaf level.
4244          *
4245          * If 2 is returned then a join was done; go to the next level.
4246          * Otherwise we are done.
4247          */
4248         for (level = 0, i = 2; i == 2; level++) {
4249                 error = xfs_btree_delrec(cur, level, &i);
4250                 if (error)
4251                         goto error0;
4252                 if (i == 2)
4253                         joined = true;
4254         }
4255
4256         /*
4257          * If we combined blocks as part of deleting the record, delrec won't
4258          * have updated the parent high keys so we have to do that here.
4259          */
4260         if (joined && (cur->bc_flags & XFS_BTREE_OVERLAPPING)) {
4261                 error = xfs_btree_updkeys_force(cur, 0);
4262                 if (error)
4263                         goto error0;
4264         }
4265
4266         if (i == 0) {
4267                 for (level = 1; level < cur->bc_nlevels; level++) {
4268                         if (cur->bc_levels[level].ptr == 0) {
4269                                 error = xfs_btree_decrement(cur, level, &i);
4270                                 if (error)
4271                                         goto error0;
4272                                 break;
4273                         }
4274                 }
4275         }
4276
4277         *stat = i;
4278         return 0;
4279 error0:
4280         return error;
4281 }
4282
4283 /*
4284  * Get the data from the pointed-to record.
4285  */
4286 int                                     /* error */
4287 xfs_btree_get_rec(
4288         struct xfs_btree_cur    *cur,   /* btree cursor */
4289         union xfs_btree_rec     **recp, /* output: btree record */
4290         int                     *stat)  /* output: success/failure */
4291 {
4292         struct xfs_btree_block  *block; /* btree block */
4293         struct xfs_buf          *bp;    /* buffer pointer */
4294         int                     ptr;    /* record number */
4295 #ifdef DEBUG
4296         int                     error;  /* error return value */
4297 #endif
4298
4299         ptr = cur->bc_levels[0].ptr;
4300         block = xfs_btree_get_block(cur, 0, &bp);
4301
4302 #ifdef DEBUG
4303         error = xfs_btree_check_block(cur, block, 0, bp);
4304         if (error)
4305                 return error;
4306 #endif
4307
4308         /*
4309          * Off the right end or left end, return failure.
4310          */
4311         if (ptr > xfs_btree_get_numrecs(block) || ptr <= 0) {
4312                 *stat = 0;
4313                 return 0;
4314         }
4315
4316         /*
4317          * Point to the record and extract its data.
4318          */
4319         *recp = xfs_btree_rec_addr(cur, ptr, block);
4320         *stat = 1;
4321         return 0;
4322 }
4323
4324 /* Visit a block in a btree. */
4325 STATIC int
4326 xfs_btree_visit_block(
4327         struct xfs_btree_cur            *cur,
4328         int                             level,
4329         xfs_btree_visit_blocks_fn       fn,
4330         void                            *data)
4331 {
4332         struct xfs_btree_block          *block;
4333         struct xfs_buf                  *bp;
4334         union xfs_btree_ptr             rptr;
4335         int                             error;
4336
4337         /* do right sibling readahead */
4338         xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
4339         block = xfs_btree_get_block(cur, level, &bp);
4340
4341         /* process the block */
4342         error = fn(cur, level, data);
4343         if (error)
4344                 return error;
4345
4346         /* now read rh sibling block for next iteration */
4347         xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
4348         if (xfs_btree_ptr_is_null(cur, &rptr))
4349                 return -ENOENT;
4350
4351         /*
4352          * We only visit blocks once in this walk, so we have to avoid the
4353          * internal xfs_btree_lookup_get_block() optimisation where it will
4354          * return the same block without checking if the right sibling points
4355          * back to us and creates a cyclic reference in the btree.
4356          */
4357         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
4358                 if (be64_to_cpu(rptr.l) == XFS_DADDR_TO_FSB(cur->bc_mp,
4359                                                         xfs_buf_daddr(bp)))
4360                         return -EFSCORRUPTED;
4361         } else {
4362                 if (be32_to_cpu(rptr.s) == xfs_daddr_to_agbno(cur->bc_mp,
4363                                                         xfs_buf_daddr(bp)))
4364                         return -EFSCORRUPTED;
4365         }
4366         return xfs_btree_lookup_get_block(cur, level, &rptr, &block);
4367 }
4368
4369
4370 /* Visit every block in a btree. */
4371 int
4372 xfs_btree_visit_blocks(
4373         struct xfs_btree_cur            *cur,
4374         xfs_btree_visit_blocks_fn       fn,
4375         unsigned int                    flags,
4376         void                            *data)
4377 {
4378         union xfs_btree_ptr             lptr;
4379         int                             level;
4380         struct xfs_btree_block          *block = NULL;
4381         int                             error = 0;
4382
4383         cur->bc_ops->init_ptr_from_cur(cur, &lptr);
4384
4385         /* for each level */
4386         for (level = cur->bc_nlevels - 1; level >= 0; level--) {
4387                 /* grab the left hand block */
4388                 error = xfs_btree_lookup_get_block(cur, level, &lptr, &block);
4389                 if (error)
4390                         return error;
4391
4392                 /* readahead the left most block for the next level down */
4393                 if (level > 0) {
4394                         union xfs_btree_ptr     *ptr;
4395
4396                         ptr = xfs_btree_ptr_addr(cur, 1, block);
4397                         xfs_btree_readahead_ptr(cur, ptr, 1);
4398
4399                         /* save for the next iteration of the loop */
4400                         xfs_btree_copy_ptrs(cur, &lptr, ptr, 1);
4401
4402                         if (!(flags & XFS_BTREE_VISIT_LEAVES))
4403                                 continue;
4404                 } else if (!(flags & XFS_BTREE_VISIT_RECORDS)) {
4405                         continue;
4406                 }
4407
4408                 /* for each buffer in the level */
4409                 do {
4410                         error = xfs_btree_visit_block(cur, level, fn, data);
4411                 } while (!error);
4412
4413                 if (error != -ENOENT)
4414                         return error;
4415         }
4416
4417         return 0;
4418 }
4419
4420 /*
4421  * Change the owner of a btree.
4422  *
4423  * The mechanism we use here is ordered buffer logging. Because we don't know
4424  * how many buffers were are going to need to modify, we don't really want to
4425  * have to make transaction reservations for the worst case of every buffer in a
4426  * full size btree as that may be more space that we can fit in the log....
4427  *
4428  * We do the btree walk in the most optimal manner possible - we have sibling
4429  * pointers so we can just walk all the blocks on each level from left to right
4430  * in a single pass, and then move to the next level and do the same. We can
4431  * also do readahead on the sibling pointers to get IO moving more quickly,
4432  * though for slow disks this is unlikely to make much difference to performance
4433  * as the amount of CPU work we have to do before moving to the next block is
4434  * relatively small.
4435  *
4436  * For each btree block that we load, modify the owner appropriately, set the
4437  * buffer as an ordered buffer and log it appropriately. We need to ensure that
4438  * we mark the region we change dirty so that if the buffer is relogged in
4439  * a subsequent transaction the changes we make here as an ordered buffer are
4440  * correctly relogged in that transaction.  If we are in recovery context, then
4441  * just queue the modified buffer as delayed write buffer so the transaction
4442  * recovery completion writes the changes to disk.
4443  */
4444 struct xfs_btree_block_change_owner_info {
4445         uint64_t                new_owner;
4446         struct list_head        *buffer_list;
4447 };
4448
4449 static int
4450 xfs_btree_block_change_owner(
4451         struct xfs_btree_cur    *cur,
4452         int                     level,
4453         void                    *data)
4454 {
4455         struct xfs_btree_block_change_owner_info        *bbcoi = data;
4456         struct xfs_btree_block  *block;
4457         struct xfs_buf          *bp;
4458
4459         /* modify the owner */
4460         block = xfs_btree_get_block(cur, level, &bp);
4461         if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
4462                 if (block->bb_u.l.bb_owner == cpu_to_be64(bbcoi->new_owner))
4463                         return 0;
4464                 block->bb_u.l.bb_owner = cpu_to_be64(bbcoi->new_owner);
4465         } else {
4466                 if (block->bb_u.s.bb_owner == cpu_to_be32(bbcoi->new_owner))
4467                         return 0;
4468                 block->bb_u.s.bb_owner = cpu_to_be32(bbcoi->new_owner);
4469         }
4470
4471         /*
4472          * If the block is a root block hosted in an inode, we might not have a
4473          * buffer pointer here and we shouldn't attempt to log the change as the
4474          * information is already held in the inode and discarded when the root
4475          * block is formatted into the on-disk inode fork. We still change it,
4476          * though, so everything is consistent in memory.
4477          */
4478         if (!bp) {
4479                 ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
4480                 ASSERT(level == cur->bc_nlevels - 1);
4481                 return 0;
4482         }
4483
4484         if (cur->bc_tp) {
4485                 if (!xfs_trans_ordered_buf(cur->bc_tp, bp)) {
4486                         xfs_btree_log_block(cur, bp, XFS_BB_OWNER);
4487                         return -EAGAIN;
4488                 }
4489         } else {
4490                 xfs_buf_delwri_queue(bp, bbcoi->buffer_list);
4491         }
4492
4493         return 0;
4494 }
4495
4496 int
4497 xfs_btree_change_owner(
4498         struct xfs_btree_cur    *cur,
4499         uint64_t                new_owner,
4500         struct list_head        *buffer_list)
4501 {
4502         struct xfs_btree_block_change_owner_info        bbcoi;
4503
4504         bbcoi.new_owner = new_owner;
4505         bbcoi.buffer_list = buffer_list;
4506
4507         return xfs_btree_visit_blocks(cur, xfs_btree_block_change_owner,
4508                         XFS_BTREE_VISIT_ALL, &bbcoi);
4509 }
4510
4511 /* Verify the v5 fields of a long-format btree block. */
4512 xfs_failaddr_t
4513 xfs_btree_lblock_v5hdr_verify(
4514         struct xfs_buf          *bp,
4515         uint64_t                owner)
4516 {
4517         struct xfs_mount        *mp = bp->b_mount;
4518         struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
4519
4520         if (!xfs_has_crc(mp))
4521                 return __this_address;
4522         if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
4523                 return __this_address;
4524         if (block->bb_u.l.bb_blkno != cpu_to_be64(xfs_buf_daddr(bp)))
4525                 return __this_address;
4526         if (owner != XFS_RMAP_OWN_UNKNOWN &&
4527             be64_to_cpu(block->bb_u.l.bb_owner) != owner)
4528                 return __this_address;
4529         return NULL;
4530 }
4531
4532 /* Verify a long-format btree block. */
4533 xfs_failaddr_t
4534 xfs_btree_lblock_verify(
4535         struct xfs_buf          *bp,
4536         unsigned int            max_recs)
4537 {
4538         struct xfs_mount        *mp = bp->b_mount;
4539         struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
4540         xfs_fsblock_t           fsb;
4541         xfs_failaddr_t          fa;
4542
4543         /* numrecs verification */
4544         if (be16_to_cpu(block->bb_numrecs) > max_recs)
4545                 return __this_address;
4546
4547         /* sibling pointer verification */
4548         fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
4549         fa = xfs_btree_check_lblock_siblings(mp, NULL, -1, fsb,
4550                         block->bb_u.l.bb_leftsib);
4551         if (!fa)
4552                 fa = xfs_btree_check_lblock_siblings(mp, NULL, -1, fsb,
4553                                 block->bb_u.l.bb_rightsib);
4554         return fa;
4555 }
4556
4557 /**
4558  * xfs_btree_sblock_v5hdr_verify() -- verify the v5 fields of a short-format
4559  *                                    btree block
4560  *
4561  * @bp: buffer containing the btree block
4562  */
4563 xfs_failaddr_t
4564 xfs_btree_sblock_v5hdr_verify(
4565         struct xfs_buf          *bp)
4566 {
4567         struct xfs_mount        *mp = bp->b_mount;
4568         struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
4569         struct xfs_perag        *pag = bp->b_pag;
4570
4571         if (!xfs_has_crc(mp))
4572                 return __this_address;
4573         if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
4574                 return __this_address;
4575         if (block->bb_u.s.bb_blkno != cpu_to_be64(xfs_buf_daddr(bp)))
4576                 return __this_address;
4577         if (pag && be32_to_cpu(block->bb_u.s.bb_owner) != pag->pag_agno)
4578                 return __this_address;
4579         return NULL;
4580 }
4581
4582 /**
4583  * xfs_btree_sblock_verify() -- verify a short-format btree block
4584  *
4585  * @bp: buffer containing the btree block
4586  * @max_recs: maximum records allowed in this btree node
4587  */
4588 xfs_failaddr_t
4589 xfs_btree_sblock_verify(
4590         struct xfs_buf          *bp,
4591         unsigned int            max_recs)
4592 {
4593         struct xfs_mount        *mp = bp->b_mount;
4594         struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
4595         xfs_agblock_t           agbno;
4596         xfs_failaddr_t          fa;
4597
4598         /* numrecs verification */
4599         if (be16_to_cpu(block->bb_numrecs) > max_recs)
4600                 return __this_address;
4601
4602         /* sibling pointer verification */
4603         agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
4604         fa = xfs_btree_check_sblock_siblings(bp->b_pag, NULL, -1, agbno,
4605                         block->bb_u.s.bb_leftsib);
4606         if (!fa)
4607                 fa = xfs_btree_check_sblock_siblings(bp->b_pag, NULL, -1, agbno,
4608                                 block->bb_u.s.bb_rightsib);
4609         return fa;
4610 }
4611
4612 /*
4613  * For the given limits on leaf and keyptr records per block, calculate the
4614  * height of the tree needed to index the number of leaf records.
4615  */
4616 unsigned int
4617 xfs_btree_compute_maxlevels(
4618         const unsigned int      *limits,
4619         unsigned long long      records)
4620 {
4621         unsigned long long      level_blocks = howmany_64(records, limits[0]);
4622         unsigned int            height = 1;
4623
4624         while (level_blocks > 1) {
4625                 level_blocks = howmany_64(level_blocks, limits[1]);
4626                 height++;
4627         }
4628
4629         return height;
4630 }
4631
4632 /*
4633  * For the given limits on leaf and keyptr records per block, calculate the
4634  * number of blocks needed to index the given number of leaf records.
4635  */
4636 unsigned long long
4637 xfs_btree_calc_size(
4638         const unsigned int      *limits,
4639         unsigned long long      records)
4640 {
4641         unsigned long long      level_blocks = howmany_64(records, limits[0]);
4642         unsigned long long      blocks = level_blocks;
4643
4644         while (level_blocks > 1) {
4645                 level_blocks = howmany_64(level_blocks, limits[1]);
4646                 blocks += level_blocks;
4647         }
4648
4649         return blocks;
4650 }
4651
4652 /*
4653  * Given a number of available blocks for the btree to consume with records and
4654  * pointers, calculate the height of the tree needed to index all the records
4655  * that space can hold based on the number of pointers each interior node
4656  * holds.
4657  *
4658  * We start by assuming a single level tree consumes a single block, then track
4659  * the number of blocks each node level consumes until we no longer have space
4660  * to store the next node level. At this point, we are indexing all the leaf
4661  * blocks in the space, and there's no more free space to split the tree any
4662  * further. That's our maximum btree height.
4663  */
4664 unsigned int
4665 xfs_btree_space_to_height(
4666         const unsigned int      *limits,
4667         unsigned long long      leaf_blocks)
4668 {
4669         unsigned long long      node_blocks = limits[1];
4670         unsigned long long      blocks_left = leaf_blocks - 1;
4671         unsigned int            height = 1;
4672
4673         if (leaf_blocks < 1)
4674                 return 0;
4675
4676         while (node_blocks < blocks_left) {
4677                 blocks_left -= node_blocks;
4678                 node_blocks *= limits[1];
4679                 height++;
4680         }
4681
4682         return height;
4683 }
4684
4685 /*
4686  * Query a regular btree for all records overlapping a given interval.
4687  * Start with a LE lookup of the key of low_rec and return all records
4688  * until we find a record with a key greater than the key of high_rec.
4689  */
4690 STATIC int
4691 xfs_btree_simple_query_range(
4692         struct xfs_btree_cur            *cur,
4693         const union xfs_btree_key       *low_key,
4694         const union xfs_btree_key       *high_key,
4695         xfs_btree_query_range_fn        fn,
4696         void                            *priv)
4697 {
4698         union xfs_btree_rec             *recp;
4699         union xfs_btree_key             rec_key;
4700         int64_t                         diff;
4701         int                             stat;
4702         bool                            firstrec = true;
4703         int                             error;
4704
4705         ASSERT(cur->bc_ops->init_high_key_from_rec);
4706         ASSERT(cur->bc_ops->diff_two_keys);
4707
4708         /*
4709          * Find the leftmost record.  The btree cursor must be set
4710          * to the low record used to generate low_key.
4711          */
4712         stat = 0;
4713         error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
4714         if (error)
4715                 goto out;
4716
4717         /* Nothing?  See if there's anything to the right. */
4718         if (!stat) {
4719                 error = xfs_btree_increment(cur, 0, &stat);
4720                 if (error)
4721                         goto out;
4722         }
4723
4724         while (stat) {
4725                 /* Find the record. */
4726                 error = xfs_btree_get_rec(cur, &recp, &stat);
4727                 if (error || !stat)
4728                         break;
4729
4730                 /* Skip if high_key(rec) < low_key. */
4731                 if (firstrec) {
4732                         cur->bc_ops->init_high_key_from_rec(&rec_key, recp);
4733                         firstrec = false;
4734                         diff = cur->bc_ops->diff_two_keys(cur, low_key,
4735                                         &rec_key);
4736                         if (diff > 0)
4737                                 goto advloop;
4738                 }
4739
4740                 /* Stop if high_key < low_key(rec). */
4741                 cur->bc_ops->init_key_from_rec(&rec_key, recp);
4742                 diff = cur->bc_ops->diff_two_keys(cur, &rec_key, high_key);
4743                 if (diff > 0)
4744                         break;
4745
4746                 /* Callback */
4747                 error = fn(cur, recp, priv);
4748                 if (error)
4749                         break;
4750
4751 advloop:
4752                 /* Move on to the next record. */
4753                 error = xfs_btree_increment(cur, 0, &stat);
4754                 if (error)
4755                         break;
4756         }
4757
4758 out:
4759         return error;
4760 }
4761
4762 /*
4763  * Query an overlapped interval btree for all records overlapping a given
4764  * interval.  This function roughly follows the algorithm given in
4765  * "Interval Trees" of _Introduction to Algorithms_, which is section
4766  * 14.3 in the 2nd and 3rd editions.
4767  *
4768  * First, generate keys for the low and high records passed in.
4769  *
4770  * For any leaf node, generate the high and low keys for the record.
4771  * If the record keys overlap with the query low/high keys, pass the
4772  * record to the function iterator.
4773  *
4774  * For any internal node, compare the low and high keys of each
4775  * pointer against the query low/high keys.  If there's an overlap,
4776  * follow the pointer.
4777  *
4778  * As an optimization, we stop scanning a block when we find a low key
4779  * that is greater than the query's high key.
4780  */
4781 STATIC int
4782 xfs_btree_overlapped_query_range(
4783         struct xfs_btree_cur            *cur,
4784         const union xfs_btree_key       *low_key,
4785         const union xfs_btree_key       *high_key,
4786         xfs_btree_query_range_fn        fn,
4787         void                            *priv)
4788 {
4789         union xfs_btree_ptr             ptr;
4790         union xfs_btree_ptr             *pp;
4791         union xfs_btree_key             rec_key;
4792         union xfs_btree_key             rec_hkey;
4793         union xfs_btree_key             *lkp;
4794         union xfs_btree_key             *hkp;
4795         union xfs_btree_rec             *recp;
4796         struct xfs_btree_block          *block;
4797         int64_t                         ldiff;
4798         int64_t                         hdiff;
4799         int                             level;
4800         struct xfs_buf                  *bp;
4801         int                             i;
4802         int                             error;
4803
4804         /* Load the root of the btree. */
4805         level = cur->bc_nlevels - 1;
4806         cur->bc_ops->init_ptr_from_cur(cur, &ptr);
4807         error = xfs_btree_lookup_get_block(cur, level, &ptr, &block);
4808         if (error)
4809                 return error;
4810         xfs_btree_get_block(cur, level, &bp);
4811         trace_xfs_btree_overlapped_query_range(cur, level, bp);
4812 #ifdef DEBUG
4813         error = xfs_btree_check_block(cur, block, level, bp);
4814         if (error)
4815                 goto out;
4816 #endif
4817         cur->bc_levels[level].ptr = 1;
4818
4819         while (level < cur->bc_nlevels) {
4820                 block = xfs_btree_get_block(cur, level, &bp);
4821
4822                 /* End of node, pop back towards the root. */
4823                 if (cur->bc_levels[level].ptr >
4824                                         be16_to_cpu(block->bb_numrecs)) {
4825 pop_up:
4826                         if (level < cur->bc_nlevels - 1)
4827                                 cur->bc_levels[level + 1].ptr++;
4828                         level++;
4829                         continue;
4830                 }
4831
4832                 if (level == 0) {
4833                         /* Handle a leaf node. */
4834                         recp = xfs_btree_rec_addr(cur, cur->bc_levels[0].ptr,
4835                                         block);
4836
4837                         cur->bc_ops->init_high_key_from_rec(&rec_hkey, recp);
4838                         ldiff = cur->bc_ops->diff_two_keys(cur, &rec_hkey,
4839                                         low_key);
4840
4841                         cur->bc_ops->init_key_from_rec(&rec_key, recp);
4842                         hdiff = cur->bc_ops->diff_two_keys(cur, high_key,
4843                                         &rec_key);
4844
4845                         /*
4846                          * If (record's high key >= query's low key) and
4847                          *    (query's high key >= record's low key), then
4848                          * this record overlaps the query range; callback.
4849                          */
4850                         if (ldiff >= 0 && hdiff >= 0) {
4851                                 error = fn(cur, recp, priv);
4852                                 if (error)
4853                                         break;
4854                         } else if (hdiff < 0) {
4855                                 /* Record is larger than high key; pop. */
4856                                 goto pop_up;
4857                         }
4858                         cur->bc_levels[level].ptr++;
4859                         continue;
4860                 }
4861
4862                 /* Handle an internal node. */
4863                 lkp = xfs_btree_key_addr(cur, cur->bc_levels[level].ptr, block);
4864                 hkp = xfs_btree_high_key_addr(cur, cur->bc_levels[level].ptr,
4865                                 block);
4866                 pp = xfs_btree_ptr_addr(cur, cur->bc_levels[level].ptr, block);
4867
4868                 ldiff = cur->bc_ops->diff_two_keys(cur, hkp, low_key);
4869                 hdiff = cur->bc_ops->diff_two_keys(cur, high_key, lkp);
4870
4871                 /*
4872                  * If (pointer's high key >= query's low key) and
4873                  *    (query's high key >= pointer's low key), then
4874                  * this record overlaps the query range; follow pointer.
4875                  */
4876                 if (ldiff >= 0 && hdiff >= 0) {
4877                         level--;
4878                         error = xfs_btree_lookup_get_block(cur, level, pp,
4879                                         &block);
4880                         if (error)
4881                                 goto out;
4882                         xfs_btree_get_block(cur, level, &bp);
4883                         trace_xfs_btree_overlapped_query_range(cur, level, bp);
4884 #ifdef DEBUG
4885                         error = xfs_btree_check_block(cur, block, level, bp);
4886                         if (error)
4887                                 goto out;
4888 #endif
4889                         cur->bc_levels[level].ptr = 1;
4890                         continue;
4891                 } else if (hdiff < 0) {
4892                         /* The low key is larger than the upper range; pop. */
4893                         goto pop_up;
4894                 }
4895                 cur->bc_levels[level].ptr++;
4896         }
4897
4898 out:
4899         /*
4900          * If we don't end this function with the cursor pointing at a record
4901          * block, a subsequent non-error cursor deletion will not release
4902          * node-level buffers, causing a buffer leak.  This is quite possible
4903          * with a zero-results range query, so release the buffers if we
4904          * failed to return any results.
4905          */
4906         if (cur->bc_levels[0].bp == NULL) {
4907                 for (i = 0; i < cur->bc_nlevels; i++) {
4908                         if (cur->bc_levels[i].bp) {
4909                                 xfs_trans_brelse(cur->bc_tp,
4910                                                 cur->bc_levels[i].bp);
4911                                 cur->bc_levels[i].bp = NULL;
4912                                 cur->bc_levels[i].ptr = 0;
4913                                 cur->bc_levels[i].ra = 0;
4914                         }
4915                 }
4916         }
4917
4918         return error;
4919 }
4920
4921 /*
4922  * Query a btree for all records overlapping a given interval of keys.  The
4923  * supplied function will be called with each record found; return one of the
4924  * XFS_BTREE_QUERY_RANGE_{CONTINUE,ABORT} values or the usual negative error
4925  * code.  This function returns -ECANCELED, zero, or a negative error code.
4926  */
4927 int
4928 xfs_btree_query_range(
4929         struct xfs_btree_cur            *cur,
4930         const union xfs_btree_irec      *low_rec,
4931         const union xfs_btree_irec      *high_rec,
4932         xfs_btree_query_range_fn        fn,
4933         void                            *priv)
4934 {
4935         union xfs_btree_rec             rec;
4936         union xfs_btree_key             low_key;
4937         union xfs_btree_key             high_key;
4938
4939         /* Find the keys of both ends of the interval. */
4940         cur->bc_rec = *high_rec;
4941         cur->bc_ops->init_rec_from_cur(cur, &rec);
4942         cur->bc_ops->init_key_from_rec(&high_key, &rec);
4943
4944         cur->bc_rec = *low_rec;
4945         cur->bc_ops->init_rec_from_cur(cur, &rec);
4946         cur->bc_ops->init_key_from_rec(&low_key, &rec);
4947
4948         /* Enforce low key < high key. */
4949         if (cur->bc_ops->diff_two_keys(cur, &low_key, &high_key) > 0)
4950                 return -EINVAL;
4951
4952         if (!(cur->bc_flags & XFS_BTREE_OVERLAPPING))
4953                 return xfs_btree_simple_query_range(cur, &low_key,
4954                                 &high_key, fn, priv);
4955         return xfs_btree_overlapped_query_range(cur, &low_key, &high_key,
4956                         fn, priv);
4957 }
4958
4959 /* Query a btree for all records. */
4960 int
4961 xfs_btree_query_all(
4962         struct xfs_btree_cur            *cur,
4963         xfs_btree_query_range_fn        fn,
4964         void                            *priv)
4965 {
4966         union xfs_btree_key             low_key;
4967         union xfs_btree_key             high_key;
4968
4969         memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
4970         memset(&low_key, 0, sizeof(low_key));
4971         memset(&high_key, 0xFF, sizeof(high_key));
4972
4973         return xfs_btree_simple_query_range(cur, &low_key, &high_key, fn, priv);
4974 }
4975
4976 static int
4977 xfs_btree_count_blocks_helper(
4978         struct xfs_btree_cur    *cur,
4979         int                     level,
4980         void                    *data)
4981 {
4982         xfs_extlen_t            *blocks = data;
4983         (*blocks)++;
4984
4985         return 0;
4986 }
4987
4988 /* Count the blocks in a btree and return the result in *blocks. */
4989 int
4990 xfs_btree_count_blocks(
4991         struct xfs_btree_cur    *cur,
4992         xfs_extlen_t            *blocks)
4993 {
4994         *blocks = 0;
4995         return xfs_btree_visit_blocks(cur, xfs_btree_count_blocks_helper,
4996                         XFS_BTREE_VISIT_ALL, blocks);
4997 }
4998
4999 /* Compare two btree pointers. */
5000 int64_t
5001 xfs_btree_diff_two_ptrs(
5002         struct xfs_btree_cur            *cur,
5003         const union xfs_btree_ptr       *a,
5004         const union xfs_btree_ptr       *b)
5005 {
5006         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
5007                 return (int64_t)be64_to_cpu(a->l) - be64_to_cpu(b->l);
5008         return (int64_t)be32_to_cpu(a->s) - be32_to_cpu(b->s);
5009 }
5010
5011 /* If there's an extent, we're done. */
5012 STATIC int
5013 xfs_btree_has_record_helper(
5014         struct xfs_btree_cur            *cur,
5015         const union xfs_btree_rec       *rec,
5016         void                            *priv)
5017 {
5018         return -ECANCELED;
5019 }
5020
5021 /* Is there a record covering a given range of keys? */
5022 int
5023 xfs_btree_has_record(
5024         struct xfs_btree_cur            *cur,
5025         const union xfs_btree_irec      *low,
5026         const union xfs_btree_irec      *high,
5027         bool                            *exists)
5028 {
5029         int                             error;
5030
5031         error = xfs_btree_query_range(cur, low, high,
5032                         &xfs_btree_has_record_helper, NULL);
5033         if (error == -ECANCELED) {
5034                 *exists = true;
5035                 return 0;
5036         }
5037         *exists = false;
5038         return error;
5039 }
5040
5041 /* Are there more records in this btree? */
5042 bool
5043 xfs_btree_has_more_records(
5044         struct xfs_btree_cur    *cur)
5045 {
5046         struct xfs_btree_block  *block;
5047         struct xfs_buf          *bp;
5048
5049         block = xfs_btree_get_block(cur, 0, &bp);
5050
5051         /* There are still records in this block. */
5052         if (cur->bc_levels[0].ptr < xfs_btree_get_numrecs(block))
5053                 return true;
5054
5055         /* There are more record blocks. */
5056         if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
5057                 return block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK);
5058         else
5059                 return block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK);
5060 }
5061
5062 /* Set up all the btree cursor caches. */
5063 int __init
5064 xfs_btree_init_cur_caches(void)
5065 {
5066         int             error;
5067
5068         error = xfs_allocbt_init_cur_cache();
5069         if (error)
5070                 return error;
5071         error = xfs_inobt_init_cur_cache();
5072         if (error)
5073                 goto err;
5074         error = xfs_bmbt_init_cur_cache();
5075         if (error)
5076                 goto err;
5077         error = xfs_rmapbt_init_cur_cache();
5078         if (error)
5079                 goto err;
5080         error = xfs_refcountbt_init_cur_cache();
5081         if (error)
5082                 goto err;
5083
5084         return 0;
5085 err:
5086         xfs_btree_destroy_cur_caches();
5087         return error;
5088 }
5089
5090 /* Destroy all the btree cursor caches, if they've been allocated. */
5091 void
5092 xfs_btree_destroy_cur_caches(void)
5093 {
5094         xfs_allocbt_destroy_cur_cache();
5095         xfs_inobt_destroy_cur_cache();
5096         xfs_bmbt_destroy_cur_cache();
5097         xfs_rmapbt_destroy_cur_cache();
5098         xfs_refcountbt_destroy_cur_cache();
5099 }