libxfs/xfs_btree.h

   1 /*
   2  * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #ifndef __XFS_BTREE_H__
  19 #define __XFS_BTREE_H__
  20
  21 struct xfs_buf;
  22 struct xfs_defer_ops;
  23 struct xfs_inode;
  24 struct xfs_mount;
  25 struct xfs_trans;
  26
  27 extern kmem_zone_t      *xfs_btree_cur_zone;
  28
  29 /*
  30  * Generic key, ptr and record wrapper structures.
  31  *
  32  * These are disk format structures, and are converted where necessary
  33  * by the btree specific code that needs to interpret them.
  34  */
  35 union xfs_btree_ptr {
  36         __be32                  s;      /* short form ptr */
  37         __be64                  l;      /* long form ptr */
  38 };
  39
  40 union xfs_btree_key {
  41         struct xfs_bmbt_key             bmbt;
  42         xfs_bmdr_key_t                  bmbr;   /* bmbt root block */
  43         xfs_alloc_key_t                 alloc;
  44         struct xfs_inobt_key            inobt;
  45         struct xfs_rmap_key             rmap;
  46 };
  47
  48 /*
  49  * In-core key that holds both low and high keys for overlapped btrees.
  50  * The two keys are packed next to each other on disk, so do the same
  51  * in memory.  Preserve the existing xfs_btree_key as a single key to
  52  * avoid the mental model breakage that would happen if we passed a
  53  * bigkey into a function that operates on a single key.
  54  */
  55 union xfs_btree_bigkey {
  56         struct xfs_bmbt_key             bmbt;
  57         xfs_bmdr_key_t                  bmbr;   /* bmbt root block */
  58         xfs_alloc_key_t                 alloc;
  59         struct xfs_inobt_key            inobt;
  60         struct {
  61                 struct xfs_rmap_key     rmap;
  62                 struct xfs_rmap_key     rmap_hi;
  63         };
  64 };
  65
  66 union xfs_btree_rec {
  67         struct xfs_bmbt_rec             bmbt;
  68         xfs_bmdr_rec_t                  bmbr;   /* bmbt root block */
  69         struct xfs_alloc_rec            alloc;
  70         struct xfs_inobt_rec            inobt;
  71         struct xfs_rmap_rec             rmap;
  72 };
  73
  74 /*
  75  * This nonsense is to make -wlint happy.
  76  */
  77 #define XFS_LOOKUP_EQ   ((xfs_lookup_t)XFS_LOOKUP_EQi)
  78 #define XFS_LOOKUP_LE   ((xfs_lookup_t)XFS_LOOKUP_LEi)
  79 #define XFS_LOOKUP_GE   ((xfs_lookup_t)XFS_LOOKUP_GEi)
  80
  81 #define XFS_BTNUM_BNO   ((xfs_btnum_t)XFS_BTNUM_BNOi)
  82 #define XFS_BTNUM_CNT   ((xfs_btnum_t)XFS_BTNUM_CNTi)
  83 #define XFS_BTNUM_BMAP  ((xfs_btnum_t)XFS_BTNUM_BMAPi)
  84 #define XFS_BTNUM_INO   ((xfs_btnum_t)XFS_BTNUM_INOi)
  85 #define XFS_BTNUM_FINO  ((xfs_btnum_t)XFS_BTNUM_FINOi)
  86 #define XFS_BTNUM_RMAP  ((xfs_btnum_t)XFS_BTNUM_RMAPi)
  87
  88 /*
  89  * For logging record fields.
  90  */
  91 #define XFS_BB_MAGIC            (1 << 0)
  92 #define XFS_BB_LEVEL            (1 << 1)
  93 #define XFS_BB_NUMRECS          (1 << 2)
  94 #define XFS_BB_LEFTSIB          (1 << 3)
  95 #define XFS_BB_RIGHTSIB         (1 << 4)
  96 #define XFS_BB_BLKNO            (1 << 5)
  97 #define XFS_BB_LSN              (1 << 6)
  98 #define XFS_BB_UUID             (1 << 7)
  99 #define XFS_BB_OWNER            (1 << 8)
 100 #define XFS_BB_NUM_BITS         5
 101 #define XFS_BB_ALL_BITS         ((1 << XFS_BB_NUM_BITS) - 1)
 102 #define XFS_BB_NUM_BITS_CRC     9
 103 #define XFS_BB_ALL_BITS_CRC     ((1 << XFS_BB_NUM_BITS_CRC) - 1)
 104
 105 /*
 106  * Generic stats interface
 107  */
 108 #define __XFS_BTREE_STATS_INC(mp, type, stat) \
 109         XFS_STATS_INC(mp, xs_ ## type ## _2_ ## stat)
 110 #define XFS_BTREE_STATS_INC(cur, stat)  \
 111 do {    \
 112         struct xfs_mount *__mp = cur->bc_mp; \
 113         switch (cur->bc_btnum) {  \
 114         case XFS_BTNUM_BNO: __XFS_BTREE_STATS_INC(__mp, abtb, stat); break; \
 115         case XFS_BTNUM_CNT: __XFS_BTREE_STATS_INC(__mp, abtc, stat); break; \
 116         case XFS_BTNUM_BMAP: __XFS_BTREE_STATS_INC(__mp, bmbt, stat); break; \
 117         case XFS_BTNUM_INO: __XFS_BTREE_STATS_INC(__mp, ibt, stat); break; \
 118         case XFS_BTNUM_FINO: __XFS_BTREE_STATS_INC(__mp, fibt, stat); break; \
 119         case XFS_BTNUM_RMAP: __XFS_BTREE_STATS_INC(__mp, rmap, stat); break; \
 120         case XFS_BTNUM_MAX: ASSERT(0); __mp = __mp /* fucking gcc */ ; break; \
 121         }       \
 122 } while (0)
 123
 124 #define __XFS_BTREE_STATS_ADD(mp, type, stat, val) \
 125         XFS_STATS_ADD(mp, xs_ ## type ## _2_ ## stat, val)
 126 #define XFS_BTREE_STATS_ADD(cur, stat, val)  \
 127 do {    \
 128         struct xfs_mount *__mp = cur->bc_mp; \
 129         switch (cur->bc_btnum) {  \
 130         case XFS_BTNUM_BNO:     \
 131                 __XFS_BTREE_STATS_ADD(__mp, abtb, stat, val); break; \
 132         case XFS_BTNUM_CNT:     \
 133                 __XFS_BTREE_STATS_ADD(__mp, abtc, stat, val); break; \
 134         case XFS_BTNUM_BMAP:    \
 135                 __XFS_BTREE_STATS_ADD(__mp, bmbt, stat, val); break; \
 136         case XFS_BTNUM_INO:     \
 137                 __XFS_BTREE_STATS_ADD(__mp, ibt, stat, val); break; \
 138         case XFS_BTNUM_FINO:    \
 139                 __XFS_BTREE_STATS_ADD(__mp, fibt, stat, val); break; \
 140         case XFS_BTNUM_RMAP:    \
 141                 __XFS_BTREE_STATS_ADD(__mp, rmap, stat, val); break; \
 142         case XFS_BTNUM_MAX: ASSERT(0); __mp = __mp /* fucking gcc */ ; break; \
 143         }       \
 144 } while (0)
 145
 146 #define XFS_BTREE_MAXLEVELS     9       /* max of all btrees */
 147
 148 struct xfs_btree_ops {
 149         /* size of the key and record structures */
 150         size_t  key_len;
 151         size_t  rec_len;
 152
 153         /* cursor operations */
 154         struct xfs_btree_cur *(*dup_cursor)(struct xfs_btree_cur *);
 155         void    (*update_cursor)(struct xfs_btree_cur *src,
 156                                  struct xfs_btree_cur *dst);
 157
 158         /* update btree root pointer */
 159         void    (*set_root)(struct xfs_btree_cur *cur,
 160                             union xfs_btree_ptr *nptr, int level_change);
 161
 162         /* block allocation / freeing */
 163         int     (*alloc_block)(struct xfs_btree_cur *cur,
 164                                union xfs_btree_ptr *start_bno,
 165                                union xfs_btree_ptr *new_bno,
 166                                int *stat);
 167         int     (*free_block)(struct xfs_btree_cur *cur, struct xfs_buf *bp);
 168
 169         /* update last record information */
 170         void    (*update_lastrec)(struct xfs_btree_cur *cur,
 171                                   struct xfs_btree_block *block,
 172                                   union xfs_btree_rec *rec,
 173                                   int ptr, int reason);
 174
 175         /* records in block/level */
 176         int     (*get_minrecs)(struct xfs_btree_cur *cur, int level);
 177         int     (*get_maxrecs)(struct xfs_btree_cur *cur, int level);
 178
 179         /* records on disk.  Matter for the root in inode case. */
 180         int     (*get_dmaxrecs)(struct xfs_btree_cur *cur, int level);
 181
 182         /* init values of btree structures */
 183         void    (*init_key_from_rec)(union xfs_btree_key *key,
 184                                      union xfs_btree_rec *rec);
 185         void    (*init_rec_from_cur)(struct xfs_btree_cur *cur,
 186                                      union xfs_btree_rec *rec);
 187         void    (*init_ptr_from_cur)(struct xfs_btree_cur *cur,
 188                                      union xfs_btree_ptr *ptr);
 189         void    (*init_high_key_from_rec)(union xfs_btree_key *key,
 190                                           union xfs_btree_rec *rec);
 191
 192         /* difference between key value and cursor value */
 193         __int64_t (*key_diff)(struct xfs_btree_cur *cur,
 194                               union xfs_btree_key *key);
 195
 196         /*
 197          * Difference between key2 and key1 -- positive if key1 > key2,
 198          * negative if key1 < key2, and zero if equal.
 199          */
 200         __int64_t (*diff_two_keys)(struct xfs_btree_cur *cur,
 201                                    union xfs_btree_key *key1,
 202                                    union xfs_btree_key *key2);
 203
 204         const struct xfs_buf_ops        *buf_ops;
 205
 206 #if defined(DEBUG) || defined(XFS_WARN)
 207         /* check that k1 is lower than k2 */
 208         int     (*keys_inorder)(struct xfs_btree_cur *cur,
 209                                 union xfs_btree_key *k1,
 210                                 union xfs_btree_key *k2);
 211
 212         /* check that r1 is lower than r2 */
 213         int     (*recs_inorder)(struct xfs_btree_cur *cur,
 214                                 union xfs_btree_rec *r1,
 215                                 union xfs_btree_rec *r2);
 216 #endif
 217 };
 218
 219 /*
 220  * Reasons for the update_lastrec method to be called.
 221  */
 222 #define LASTREC_UPDATE  0
 223 #define LASTREC_INSREC  1
 224 #define LASTREC_DELREC  2
 225
 226
 227 union xfs_btree_irec {
 228         struct xfs_alloc_rec_incore     a;
 229         struct xfs_bmbt_irec            b;
 230         struct xfs_inobt_rec_incore     i;
 231         struct xfs_rmap_irec            r;
 232 };
 233
 234 /*
 235  * Btree cursor structure.
 236  * This collects all information needed by the btree code in one place.
 237  */
 238 typedef struct xfs_btree_cur
 239 {
 240         struct xfs_trans        *bc_tp; /* transaction we're in, if any */
 241         struct xfs_mount        *bc_mp; /* file system mount struct */
 242         const struct xfs_btree_ops *bc_ops;
 243         uint                    bc_flags; /* btree features - below */
 244         union xfs_btree_irec    bc_rec; /* current insert/search record value */
 245         struct xfs_buf  *bc_bufs[XFS_BTREE_MAXLEVELS];  /* buf ptr per level */
 246         int             bc_ptrs[XFS_BTREE_MAXLEVELS];   /* key/record # */
 247         __uint8_t       bc_ra[XFS_BTREE_MAXLEVELS];     /* readahead bits */
 248 #define XFS_BTCUR_LEFTRA        1       /* left sibling has been read-ahead */
 249 #define XFS_BTCUR_RIGHTRA       2       /* right sibling has been read-ahead */
 250         __uint8_t       bc_nlevels;     /* number of levels in the tree */
 251         __uint8_t       bc_blocklog;    /* log2(blocksize) of btree blocks */
 252         xfs_btnum_t     bc_btnum;       /* identifies which btree type */
 253         union {
 254                 struct {                        /* needed for BNO, CNT, INO */
 255                         struct xfs_buf  *agbp;  /* agf/agi buffer pointer */
 256                         struct xfs_defer_ops *dfops;    /* deferred updates */
 257                         xfs_agnumber_t  agno;   /* ag number */
 258                 } a;
 259                 struct {                        /* needed for BMAP */
 260                         struct xfs_inode *ip;   /* pointer to our inode */
 261                         struct xfs_defer_ops *dfops;    /* deferred updates */
 262                         xfs_fsblock_t   firstblock;     /* 1st blk allocated */
 263                         int             allocated;      /* count of alloced */
 264                         short           forksize;       /* fork's inode space */
 265                         char            whichfork;      /* data or attr fork */
 266                         char            flags;          /* flags */
 267 #define XFS_BTCUR_BPRV_WASDEL   1                       /* was delayed */
 268                 } b;
 269         }               bc_private;     /* per-btree type data */
 270 } xfs_btree_cur_t;
 271
 272 /* cursor flags */
 273 #define XFS_BTREE_LONG_PTRS             (1<<0)  /* pointers are 64bits long */
 274 #define XFS_BTREE_ROOT_IN_INODE         (1<<1)  /* root may be variable size */
 275 #define XFS_BTREE_LASTREC_UPDATE        (1<<2)  /* track last rec externally */
 276 #define XFS_BTREE_CRC_BLOCKS            (1<<3)  /* uses extended btree blocks */
 277 #define XFS_BTREE_OVERLAPPING           (1<<4)  /* overlapping intervals */
 278
 279
 280 #define XFS_BTREE_NOERROR       0
 281 #define XFS_BTREE_ERROR         1
 282
 283 /*
 284  * Convert from buffer to btree block header.
 285  */
 286 #define XFS_BUF_TO_BLOCK(bp)    ((struct xfs_btree_block *)((bp)->b_addr))
 287
 288
 289 /*
 290  * Check that block header is ok.
 291  */
 292 int
 293 xfs_btree_check_block(
 294         struct xfs_btree_cur    *cur,   /* btree cursor */
 295         struct xfs_btree_block  *block, /* generic btree block pointer */
 296         int                     level,  /* level of the btree block */
 297         struct xfs_buf          *bp);   /* buffer containing block, if any */
 298
 299 /*
 300  * Check that (long) pointer is ok.
 301  */
 302 int                                     /* error (0 or EFSCORRUPTED) */
 303 xfs_btree_check_lptr(
 304         struct xfs_btree_cur    *cur,   /* btree cursor */
 305         xfs_fsblock_t           ptr,    /* btree block disk address */
 306         int                     level); /* btree block level */
 307
 308 /*
 309  * Delete the btree cursor.
 310  */
 311 void
 312 xfs_btree_del_cursor(
 313         xfs_btree_cur_t         *cur,   /* btree cursor */
 314         int                     error); /* del because of error */
 315
 316 /*
 317  * Duplicate the btree cursor.
 318  * Allocate a new one, copy the record, re-get the buffers.
 319  */
 320 int                                     /* error */
 321 xfs_btree_dup_cursor(
 322         xfs_btree_cur_t         *cur,   /* input cursor */
 323         xfs_btree_cur_t         **ncur);/* output cursor */
 324
 325 /*
 326  * Get a buffer for the block, return it with no data read.
 327  * Long-form addressing.
 328  */
 329 struct xfs_buf *                                /* buffer for fsbno */
 330 xfs_btree_get_bufl(
 331         struct xfs_mount        *mp,    /* file system mount point */
 332         struct xfs_trans        *tp,    /* transaction pointer */
 333         xfs_fsblock_t           fsbno,  /* file system block number */
 334         uint                    lock);  /* lock flags for get_buf */
 335
 336 /*
 337  * Get a buffer for the block, return it with no data read.
 338  * Short-form addressing.
 339  */
 340 struct xfs_buf *                                /* buffer for agno/agbno */
 341 xfs_btree_get_bufs(
 342         struct xfs_mount        *mp,    /* file system mount point */
 343         struct xfs_trans        *tp,    /* transaction pointer */
 344         xfs_agnumber_t          agno,   /* allocation group number */
 345         xfs_agblock_t           agbno,  /* allocation group block number */
 346         uint                    lock);  /* lock flags for get_buf */
 347
 348 /*
 349  * Check for the cursor referring to the last block at the given level.
 350  */
 351 int                                     /* 1=is last block, 0=not last block */
 352 xfs_btree_islastblock(
 353         xfs_btree_cur_t         *cur,   /* btree cursor */
 354         int                     level); /* level to check */
 355
 356 /*
 357  * Compute first and last byte offsets for the fields given.
 358  * Interprets the offsets table, which contains struct field offsets.
 359  */
 360 void
 361 xfs_btree_offsets(
 362         __int64_t               fields, /* bitmask of fields */
 363         const short             *offsets,/* table of field offsets */
 364         int                     nbits,  /* number of bits to inspect */
 365         int                     *first, /* output: first byte offset */
 366         int                     *last); /* output: last byte offset */
 367
 368 /*
 369  * Get a buffer for the block, return it read in.
 370  * Long-form addressing.
 371  */
 372 int                                     /* error */
 373 xfs_btree_read_bufl(
 374         struct xfs_mount        *mp,    /* file system mount point */
 375         struct xfs_trans        *tp,    /* transaction pointer */
 376         xfs_fsblock_t           fsbno,  /* file system block number */
 377         uint                    lock,   /* lock flags for read_buf */
 378         struct xfs_buf          **bpp,  /* buffer for fsbno */
 379         int                     refval, /* ref count value for buffer */
 380         const struct xfs_buf_ops *ops);
 381
 382 /*
 383  * Read-ahead the block, don't wait for it, don't return a buffer.
 384  * Long-form addressing.
 385  */
 386 void                                    /* error */
 387 xfs_btree_reada_bufl(
 388         struct xfs_mount        *mp,    /* file system mount point */
 389         xfs_fsblock_t           fsbno,  /* file system block number */
 390         xfs_extlen_t            count,  /* count of filesystem blocks */
 391         const struct xfs_buf_ops *ops);
 392
 393 /*
 394  * Read-ahead the block, don't wait for it, don't return a buffer.
 395  * Short-form addressing.
 396  */
 397 void                                    /* error */
 398 xfs_btree_reada_bufs(
 399         struct xfs_mount        *mp,    /* file system mount point */
 400         xfs_agnumber_t          agno,   /* allocation group number */
 401         xfs_agblock_t           agbno,  /* allocation group block number */
 402         xfs_extlen_t            count,  /* count of filesystem blocks */
 403         const struct xfs_buf_ops *ops);
 404
 405 /*
 406  * Initialise a new btree block header
 407  */
 408 void
 409 xfs_btree_init_block(
 410         struct xfs_mount *mp,
 411         struct xfs_buf  *bp,
 412         __u32           magic,
 413         __u16           level,
 414         __u16           numrecs,
 415         __u64           owner,
 416         unsigned int    flags);
 417
 418 void
 419 xfs_btree_init_block_int(
 420         struct xfs_mount        *mp,
 421         struct xfs_btree_block  *buf,
 422         xfs_daddr_t             blkno,
 423         __u32                   magic,
 424         __u16                   level,
 425         __u16                   numrecs,
 426         __u64                   owner,
 427         unsigned int            flags);
 428
 429 /*
 430  * Common btree core entry points.
 431  */
 432 int xfs_btree_increment(struct xfs_btree_cur *, int, int *);
 433 int xfs_btree_decrement(struct xfs_btree_cur *, int, int *);
 434 int xfs_btree_lookup(struct xfs_btree_cur *, xfs_lookup_t, int *);
 435 int xfs_btree_update(struct xfs_btree_cur *, union xfs_btree_rec *);
 436 int xfs_btree_new_iroot(struct xfs_btree_cur *, int *, int *);
 437 int xfs_btree_insert(struct xfs_btree_cur *, int *);
 438 int xfs_btree_delete(struct xfs_btree_cur *, int *);
 439 int xfs_btree_get_rec(struct xfs_btree_cur *, union xfs_btree_rec **, int *);
 440 int xfs_btree_change_owner(struct xfs_btree_cur *cur, __uint64_t new_owner,
 441                            struct list_head *buffer_list);
 442
 443 /*
 444  * btree block CRC helpers
 445  */
 446 void xfs_btree_lblock_calc_crc(struct xfs_buf *);
 447 bool xfs_btree_lblock_verify_crc(struct xfs_buf *);
 448 void xfs_btree_sblock_calc_crc(struct xfs_buf *);
 449 bool xfs_btree_sblock_verify_crc(struct xfs_buf *);
 450
 451 /*
 452  * Internal btree helpers also used by xfs_bmap.c.
 453  */
 454 void xfs_btree_log_block(struct xfs_btree_cur *, struct xfs_buf *, int);
 455 void xfs_btree_log_recs(struct xfs_btree_cur *, struct xfs_buf *, int, int);
 456
 457 /*
 458  * Helpers.
 459  */
 460 static inline int xfs_btree_get_numrecs(struct xfs_btree_block *block)
 461 {
 462         return be16_to_cpu(block->bb_numrecs);
 463 }
 464
 465 static inline void xfs_btree_set_numrecs(struct xfs_btree_block *block,
 466                 __uint16_t numrecs)
 467 {
 468         block->bb_numrecs = cpu_to_be16(numrecs);
 469 }
 470
 471 static inline int xfs_btree_get_level(struct xfs_btree_block *block)
 472 {
 473         return be16_to_cpu(block->bb_level);
 474 }
 475
 476
 477 /*
 478  * Min and max functions for extlen, agblock, fileoff, and filblks types.
 479  */
 480 #define XFS_EXTLEN_MIN(a,b)     min_t(xfs_extlen_t, (a), (b))
 481 #define XFS_EXTLEN_MAX(a,b)     max_t(xfs_extlen_t, (a), (b))
 482 #define XFS_AGBLOCK_MIN(a,b)    min_t(xfs_agblock_t, (a), (b))
 483 #define XFS_AGBLOCK_MAX(a,b)    max_t(xfs_agblock_t, (a), (b))
 484 #define XFS_FILEOFF_MIN(a,b)    min_t(xfs_fileoff_t, (a), (b))
 485 #define XFS_FILEOFF_MAX(a,b)    max_t(xfs_fileoff_t, (a), (b))
 486 #define XFS_FILBLKS_MIN(a,b)    min_t(xfs_filblks_t, (a), (b))
 487 #define XFS_FILBLKS_MAX(a,b)    max_t(xfs_filblks_t, (a), (b))
 488
 489 #define XFS_FSB_SANITY_CHECK(mp,fsb)    \
 490         (XFS_FSB_TO_AGNO(mp, fsb) < mp->m_sb.sb_agcount && \
 491                 XFS_FSB_TO_AGBNO(mp, fsb) < mp->m_sb.sb_agblocks)
 492
 493 /*
 494  * Trace hooks.  Currently not implemented as they need to be ported
 495  * over to the generic tracing functionality, which is some effort.
 496  *
 497  * i,j = integer (32 bit)
 498  * b = btree block buffer (xfs_buf_t)
 499  * p = btree ptr
 500  * r = btree record
 501  * k = btree key
 502  */
 503 #define XFS_BTREE_TRACE_ARGBI(c, b, i)
 504 #define XFS_BTREE_TRACE_ARGBII(c, b, i, j)
 505 #define XFS_BTREE_TRACE_ARGI(c, i)
 506 #define XFS_BTREE_TRACE_ARGIPK(c, i, p, s)
 507 #define XFS_BTREE_TRACE_ARGIPR(c, i, p, r)
 508 #define XFS_BTREE_TRACE_ARGIK(c, i, k)
 509 #define XFS_BTREE_TRACE_ARGR(c, r)
 510 #define XFS_BTREE_TRACE_CURSOR(c, t)
 511
 512 bool xfs_btree_sblock_v5hdr_verify(struct xfs_buf *bp);
 513 bool xfs_btree_sblock_verify(struct xfs_buf *bp, unsigned int max_recs);
 514 uint xfs_btree_compute_maxlevels(struct xfs_mount *mp, uint *limits,
 515                                  unsigned long len);
 516
 517 /* return codes */
 518 #define XFS_BTREE_QUERY_RANGE_CONTINUE  0       /* keep iterating */
 519 #define XFS_BTREE_QUERY_RANGE_ABORT     1       /* stop iterating */
 520 typedef int (*xfs_btree_query_range_fn)(struct xfs_btree_cur *cur,
 521                 union xfs_btree_rec *rec, void *priv);
 522
 523 int xfs_btree_query_range(struct xfs_btree_cur *cur,
 524                 union xfs_btree_irec *low_rec, union xfs_btree_irec *high_rec,
 525                 xfs_btree_query_range_fn fn, void *priv);
 526
 527 typedef int (*xfs_btree_visit_blocks_fn)(struct xfs_btree_cur *cur, int level,
 528                 void *data);
 529 int xfs_btree_visit_blocks(struct xfs_btree_cur *cur,
 530                 xfs_btree_visit_blocks_fn fn, void *data);
 531
 532 #endif  /* __XFS_BTREE_H__ */