linux/fs/xfs/xfs_btree.h
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   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
  21struct xfs_buf;
  22struct xfs_bmap_free;
  23struct xfs_inode;
  24struct xfs_mount;
  25struct xfs_trans;
  26
  27extern kmem_zone_t      *xfs_btree_cur_zone;
  28
  29/*
  30 * This nonsense is to make -wlint happy.
  31 */
  32#define XFS_LOOKUP_EQ   ((xfs_lookup_t)XFS_LOOKUP_EQi)
  33#define XFS_LOOKUP_LE   ((xfs_lookup_t)XFS_LOOKUP_LEi)
  34#define XFS_LOOKUP_GE   ((xfs_lookup_t)XFS_LOOKUP_GEi)
  35
  36#define XFS_BTNUM_BNO   ((xfs_btnum_t)XFS_BTNUM_BNOi)
  37#define XFS_BTNUM_CNT   ((xfs_btnum_t)XFS_BTNUM_CNTi)
  38#define XFS_BTNUM_BMAP  ((xfs_btnum_t)XFS_BTNUM_BMAPi)
  39#define XFS_BTNUM_INO   ((xfs_btnum_t)XFS_BTNUM_INOi)
  40
  41/*
  42 * Generic btree header.
  43 *
  44 * This is a combination of the actual format used on disk for short and long
  45 * format btrees.  The first three fields are shared by both format, but
  46 * the pointers are different and should be used with care.
  47 *
  48 * To get the size of the actual short or long form headers please use
  49 * the size macros below.  Never use sizeof(xfs_btree_block).
  50 */
  51struct xfs_btree_block {
  52        __be32          bb_magic;       /* magic number for block type */
  53        __be16          bb_level;       /* 0 is a leaf */
  54        __be16          bb_numrecs;     /* current # of data records */
  55        union {
  56                struct {
  57                        __be32          bb_leftsib;
  58                        __be32          bb_rightsib;
  59                } s;                    /* short form pointers */
  60                struct  {
  61                        __be64          bb_leftsib;
  62                        __be64          bb_rightsib;
  63                } l;                    /* long form pointers */
  64        } bb_u;                         /* rest */
  65};
  66
  67#define XFS_BTREE_SBLOCK_LEN    16      /* size of a short form block */
  68#define XFS_BTREE_LBLOCK_LEN    24      /* size of a long form block */
  69
  70
  71/*
  72 * Generic key, ptr and record wrapper structures.
  73 *
  74 * These are disk format structures, and are converted where necessary
  75 * by the btree specific code that needs to interpret them.
  76 */
  77union xfs_btree_ptr {
  78        __be32                  s;      /* short form ptr */
  79        __be64                  l;      /* long form ptr */
  80};
  81
  82union xfs_btree_key {
  83        xfs_bmbt_key_t          bmbt;
  84        xfs_bmdr_key_t          bmbr;   /* bmbt root block */
  85        xfs_alloc_key_t         alloc;
  86        xfs_inobt_key_t         inobt;
  87};
  88
  89union xfs_btree_rec {
  90        xfs_bmbt_rec_t          bmbt;
  91        xfs_bmdr_rec_t          bmbr;   /* bmbt root block */
  92        xfs_alloc_rec_t         alloc;
  93        xfs_inobt_rec_t         inobt;
  94};
  95
  96/*
  97 * For logging record fields.
  98 */
  99#define XFS_BB_MAGIC            0x01
 100#define XFS_BB_LEVEL            0x02
 101#define XFS_BB_NUMRECS          0x04
 102#define XFS_BB_LEFTSIB          0x08
 103#define XFS_BB_RIGHTSIB         0x10
 104#define XFS_BB_NUM_BITS         5
 105#define XFS_BB_ALL_BITS         ((1 << XFS_BB_NUM_BITS) - 1)
 106
 107/*
 108 * Magic numbers for btree blocks.
 109 */
 110extern const __uint32_t xfs_magics[];
 111
 112/*
 113 * Generic stats interface
 114 */
 115#define __XFS_BTREE_STATS_INC(type, stat) \
 116        XFS_STATS_INC(xs_ ## type ## _2_ ## stat)
 117#define XFS_BTREE_STATS_INC(cur, stat)  \
 118do {    \
 119        switch (cur->bc_btnum) {  \
 120        case XFS_BTNUM_BNO: __XFS_BTREE_STATS_INC(abtb, stat); break;   \
 121        case XFS_BTNUM_CNT: __XFS_BTREE_STATS_INC(abtc, stat); break;   \
 122        case XFS_BTNUM_BMAP: __XFS_BTREE_STATS_INC(bmbt, stat); break;  \
 123        case XFS_BTNUM_INO: __XFS_BTREE_STATS_INC(ibt, stat); break;    \
 124        case XFS_BTNUM_MAX: ASSERT(0); /* fucking gcc */ ; break;       \
 125        }       \
 126} while (0)
 127
 128#define __XFS_BTREE_STATS_ADD(type, stat, val) \
 129        XFS_STATS_ADD(xs_ ## type ## _2_ ## stat, val)
 130#define XFS_BTREE_STATS_ADD(cur, stat, val)  \
 131do {    \
 132        switch (cur->bc_btnum) {  \
 133        case XFS_BTNUM_BNO: __XFS_BTREE_STATS_ADD(abtb, stat, val); break; \
 134        case XFS_BTNUM_CNT: __XFS_BTREE_STATS_ADD(abtc, stat, val); break; \
 135        case XFS_BTNUM_BMAP: __XFS_BTREE_STATS_ADD(bmbt, stat, val); break; \
 136        case XFS_BTNUM_INO: __XFS_BTREE_STATS_ADD(ibt, stat, val); break; \
 137        case XFS_BTNUM_MAX: ASSERT(0); /* fucking gcc */ ; break;       \
 138        }       \
 139} while (0)
 140
 141#define XFS_BTREE_MAXLEVELS     8       /* max of all btrees */
 142
 143struct xfs_btree_ops {
 144        /* size of the key and record structures */
 145        size_t  key_len;
 146        size_t  rec_len;
 147
 148        /* cursor operations */
 149        struct xfs_btree_cur *(*dup_cursor)(struct xfs_btree_cur *);
 150        void    (*update_cursor)(struct xfs_btree_cur *src,
 151                                 struct xfs_btree_cur *dst);
 152
 153        /* update btree root pointer */
 154        void    (*set_root)(struct xfs_btree_cur *cur,
 155                            union xfs_btree_ptr *nptr, int level_change);
 156
 157        /* block allocation / freeing */
 158        int     (*alloc_block)(struct xfs_btree_cur *cur,
 159                               union xfs_btree_ptr *start_bno,
 160                               union xfs_btree_ptr *new_bno,
 161                               int length, int *stat);
 162        int     (*free_block)(struct xfs_btree_cur *cur, struct xfs_buf *bp);
 163
 164        /* update last record information */
 165        void    (*update_lastrec)(struct xfs_btree_cur *cur,
 166                                  struct xfs_btree_block *block,
 167                                  union xfs_btree_rec *rec,
 168                                  int ptr, int reason);
 169
 170        /* records in block/level */
 171        int     (*get_minrecs)(struct xfs_btree_cur *cur, int level);
 172        int     (*get_maxrecs)(struct xfs_btree_cur *cur, int level);
 173
 174        /* records on disk.  Matter for the root in inode case. */
 175        int     (*get_dmaxrecs)(struct xfs_btree_cur *cur, int level);
 176
 177        /* init values of btree structures */
 178        void    (*init_key_from_rec)(union xfs_btree_key *key,
 179                                     union xfs_btree_rec *rec);
 180        void    (*init_rec_from_key)(union xfs_btree_key *key,
 181                                     union xfs_btree_rec *rec);
 182        void    (*init_rec_from_cur)(struct xfs_btree_cur *cur,
 183                                     union xfs_btree_rec *rec);
 184        void    (*init_ptr_from_cur)(struct xfs_btree_cur *cur,
 185                                     union xfs_btree_ptr *ptr);
 186
 187        /* difference between key value and cursor value */
 188        __int64_t (*key_diff)(struct xfs_btree_cur *cur,
 189                              union xfs_btree_key *key);
 190
 191#ifdef DEBUG
 192        /* check that k1 is lower than k2 */
 193        int     (*keys_inorder)(struct xfs_btree_cur *cur,
 194                                union xfs_btree_key *k1,
 195                                union xfs_btree_key *k2);
 196
 197        /* check that r1 is lower than r2 */
 198        int     (*recs_inorder)(struct xfs_btree_cur *cur,
 199                                union xfs_btree_rec *r1,
 200                                union xfs_btree_rec *r2);
 201#endif
 202};
 203
 204/*
 205 * Reasons for the update_lastrec method to be called.
 206 */
 207#define LASTREC_UPDATE  0
 208#define LASTREC_INSREC  1
 209#define LASTREC_DELREC  2
 210
 211
 212/*
 213 * Btree cursor structure.
 214 * This collects all information needed by the btree code in one place.
 215 */
 216typedef struct xfs_btree_cur
 217{
 218        struct xfs_trans        *bc_tp; /* transaction we're in, if any */
 219        struct xfs_mount        *bc_mp; /* file system mount struct */
 220        const struct xfs_btree_ops *bc_ops;
 221        uint                    bc_flags; /* btree features - below */
 222        union {
 223                xfs_alloc_rec_incore_t  a;
 224                xfs_bmbt_irec_t         b;
 225                xfs_inobt_rec_incore_t  i;
 226        }               bc_rec;         /* current insert/search record value */
 227        struct xfs_buf  *bc_bufs[XFS_BTREE_MAXLEVELS];  /* buf ptr per level */
 228        int             bc_ptrs[XFS_BTREE_MAXLEVELS];   /* key/record # */
 229        __uint8_t       bc_ra[XFS_BTREE_MAXLEVELS];     /* readahead bits */
 230#define XFS_BTCUR_LEFTRA        1       /* left sibling has been read-ahead */
 231#define XFS_BTCUR_RIGHTRA       2       /* right sibling has been read-ahead */
 232        __uint8_t       bc_nlevels;     /* number of levels in the tree */
 233        __uint8_t       bc_blocklog;    /* log2(blocksize) of btree blocks */
 234        xfs_btnum_t     bc_btnum;       /* identifies which btree type */
 235        union {
 236                struct {                        /* needed for BNO, CNT, INO */
 237                        struct xfs_buf  *agbp;  /* agf/agi buffer pointer */
 238                        xfs_agnumber_t  agno;   /* ag number */
 239                } a;
 240                struct {                        /* needed for BMAP */
 241                        struct xfs_inode *ip;   /* pointer to our inode */
 242                        struct xfs_bmap_free *flist;    /* list to free after */
 243                        xfs_fsblock_t   firstblock;     /* 1st blk allocated */
 244                        int             allocated;      /* count of alloced */
 245                        short           forksize;       /* fork's inode space */
 246                        char            whichfork;      /* data or attr fork */
 247                        char            flags;          /* flags */
 248#define XFS_BTCUR_BPRV_WASDEL   1                       /* was delayed */
 249                } b;
 250        }               bc_private;     /* per-btree type data */
 251} xfs_btree_cur_t;
 252
 253/* cursor flags */
 254#define XFS_BTREE_LONG_PTRS             (1<<0)  /* pointers are 64bits long */
 255#define XFS_BTREE_ROOT_IN_INODE         (1<<1)  /* root may be variable size */
 256#define XFS_BTREE_LASTREC_UPDATE        (1<<2)  /* track last rec externally */
 257
 258
 259#define XFS_BTREE_NOERROR       0
 260#define XFS_BTREE_ERROR         1
 261
 262/*
 263 * Convert from buffer to btree block header.
 264 */
 265#define XFS_BUF_TO_BLOCK(bp)    ((struct xfs_btree_block *)((bp)->b_addr))
 266
 267
 268/*
 269 * Check that block header is ok.
 270 */
 271int
 272xfs_btree_check_block(
 273        struct xfs_btree_cur    *cur,   /* btree cursor */
 274        struct xfs_btree_block  *block, /* generic btree block pointer */
 275        int                     level,  /* level of the btree block */
 276        struct xfs_buf          *bp);   /* buffer containing block, if any */
 277
 278/*
 279 * Check that (long) pointer is ok.
 280 */
 281int                                     /* error (0 or EFSCORRUPTED) */
 282xfs_btree_check_lptr(
 283        struct xfs_btree_cur    *cur,   /* btree cursor */
 284        xfs_dfsbno_t            ptr,    /* btree block disk address */
 285        int                     level); /* btree block level */
 286
 287/*
 288 * Delete the btree cursor.
 289 */
 290void
 291xfs_btree_del_cursor(
 292        xfs_btree_cur_t         *cur,   /* btree cursor */
 293        int                     error); /* del because of error */
 294
 295/*
 296 * Duplicate the btree cursor.
 297 * Allocate a new one, copy the record, re-get the buffers.
 298 */
 299int                                     /* error */
 300xfs_btree_dup_cursor(
 301        xfs_btree_cur_t         *cur,   /* input cursor */
 302        xfs_btree_cur_t         **ncur);/* output cursor */
 303
 304/*
 305 * Get a buffer for the block, return it with no data read.
 306 * Long-form addressing.
 307 */
 308struct xfs_buf *                                /* buffer for fsbno */
 309xfs_btree_get_bufl(
 310        struct xfs_mount        *mp,    /* file system mount point */
 311        struct xfs_trans        *tp,    /* transaction pointer */
 312        xfs_fsblock_t           fsbno,  /* file system block number */
 313        uint                    lock);  /* lock flags for get_buf */
 314
 315/*
 316 * Get a buffer for the block, return it with no data read.
 317 * Short-form addressing.
 318 */
 319struct xfs_buf *                                /* buffer for agno/agbno */
 320xfs_btree_get_bufs(
 321        struct xfs_mount        *mp,    /* file system mount point */
 322        struct xfs_trans        *tp,    /* transaction pointer */
 323        xfs_agnumber_t          agno,   /* allocation group number */
 324        xfs_agblock_t           agbno,  /* allocation group block number */
 325        uint                    lock);  /* lock flags for get_buf */
 326
 327/*
 328 * Check for the cursor referring to the last block at the given level.
 329 */
 330int                                     /* 1=is last block, 0=not last block */
 331xfs_btree_islastblock(
 332        xfs_btree_cur_t         *cur,   /* btree cursor */
 333        int                     level); /* level to check */
 334
 335/*
 336 * Compute first and last byte offsets for the fields given.
 337 * Interprets the offsets table, which contains struct field offsets.
 338 */
 339void
 340xfs_btree_offsets(
 341        __int64_t               fields, /* bitmask of fields */
 342        const short             *offsets,/* table of field offsets */
 343        int                     nbits,  /* number of bits to inspect */
 344        int                     *first, /* output: first byte offset */
 345        int                     *last); /* output: last byte offset */
 346
 347/*
 348 * Get a buffer for the block, return it read in.
 349 * Long-form addressing.
 350 */
 351int                                     /* error */
 352xfs_btree_read_bufl(
 353        struct xfs_mount        *mp,    /* file system mount point */
 354        struct xfs_trans        *tp,    /* transaction pointer */
 355        xfs_fsblock_t           fsbno,  /* file system block number */
 356        uint                    lock,   /* lock flags for read_buf */
 357        struct xfs_buf          **bpp,  /* buffer for fsbno */
 358        int                     refval);/* ref count value for buffer */
 359
 360/*
 361 * Read-ahead the block, don't wait for it, don't return a buffer.
 362 * Long-form addressing.
 363 */
 364void                                    /* error */
 365xfs_btree_reada_bufl(
 366        struct xfs_mount        *mp,    /* file system mount point */
 367        xfs_fsblock_t           fsbno,  /* file system block number */
 368        xfs_extlen_t            count); /* count of filesystem blocks */
 369
 370/*
 371 * Read-ahead the block, don't wait for it, don't return a buffer.
 372 * Short-form addressing.
 373 */
 374void                                    /* error */
 375xfs_btree_reada_bufs(
 376        struct xfs_mount        *mp,    /* file system mount point */
 377        xfs_agnumber_t          agno,   /* allocation group number */
 378        xfs_agblock_t           agbno,  /* allocation group block number */
 379        xfs_extlen_t            count); /* count of filesystem blocks */
 380
 381
 382/*
 383 * Common btree core entry points.
 384 */
 385int xfs_btree_increment(struct xfs_btree_cur *, int, int *);
 386int xfs_btree_decrement(struct xfs_btree_cur *, int, int *);
 387int xfs_btree_lookup(struct xfs_btree_cur *, xfs_lookup_t, int *);
 388int xfs_btree_update(struct xfs_btree_cur *, union xfs_btree_rec *);
 389int xfs_btree_new_iroot(struct xfs_btree_cur *, int *, int *);
 390int xfs_btree_insert(struct xfs_btree_cur *, int *);
 391int xfs_btree_delete(struct xfs_btree_cur *, int *);
 392int xfs_btree_get_rec(struct xfs_btree_cur *, union xfs_btree_rec **, int *);
 393
 394/*
 395 * Internal btree helpers also used by xfs_bmap.c.
 396 */
 397void xfs_btree_log_block(struct xfs_btree_cur *, struct xfs_buf *, int);
 398void xfs_btree_log_recs(struct xfs_btree_cur *, struct xfs_buf *, int, int);
 399
 400/*
 401 * Helpers.
 402 */
 403static inline int xfs_btree_get_numrecs(struct xfs_btree_block *block)
 404{
 405        return be16_to_cpu(block->bb_numrecs);
 406}
 407
 408static inline void xfs_btree_set_numrecs(struct xfs_btree_block *block,
 409                __uint16_t numrecs)
 410{
 411        block->bb_numrecs = cpu_to_be16(numrecs);
 412}
 413
 414static inline int xfs_btree_get_level(struct xfs_btree_block *block)
 415{
 416        return be16_to_cpu(block->bb_level);
 417}
 418
 419
 420/*
 421 * Min and max functions for extlen, agblock, fileoff, and filblks types.
 422 */
 423#define XFS_EXTLEN_MIN(a,b)     min_t(xfs_extlen_t, (a), (b))
 424#define XFS_EXTLEN_MAX(a,b)     max_t(xfs_extlen_t, (a), (b))
 425#define XFS_AGBLOCK_MIN(a,b)    min_t(xfs_agblock_t, (a), (b))
 426#define XFS_AGBLOCK_MAX(a,b)    max_t(xfs_agblock_t, (a), (b))
 427#define XFS_FILEOFF_MIN(a,b)    min_t(xfs_fileoff_t, (a), (b))
 428#define XFS_FILEOFF_MAX(a,b)    max_t(xfs_fileoff_t, (a), (b))
 429#define XFS_FILBLKS_MIN(a,b)    min_t(xfs_filblks_t, (a), (b))
 430#define XFS_FILBLKS_MAX(a,b)    max_t(xfs_filblks_t, (a), (b))
 431
 432#define XFS_FSB_SANITY_CHECK(mp,fsb)    \
 433        (XFS_FSB_TO_AGNO(mp, fsb) < mp->m_sb.sb_agcount && \
 434                XFS_FSB_TO_AGBNO(mp, fsb) < mp->m_sb.sb_agblocks)
 435
 436/*
 437 * Trace hooks.  Currently not implemented as they need to be ported
 438 * over to the generic tracing functionality, which is some effort.
 439 *
 440 * i,j = integer (32 bit)
 441 * b = btree block buffer (xfs_buf_t)
 442 * p = btree ptr
 443 * r = btree record
 444 * k = btree key
 445 */
 446#define XFS_BTREE_TRACE_ARGBI(c, b, i)
 447#define XFS_BTREE_TRACE_ARGBII(c, b, i, j)
 448#define XFS_BTREE_TRACE_ARGI(c, i)
 449#define XFS_BTREE_TRACE_ARGIPK(c, i, p, s)
 450#define XFS_BTREE_TRACE_ARGIPR(c, i, p, r)
 451#define XFS_BTREE_TRACE_ARGIK(c, i, k)
 452#define XFS_BTREE_TRACE_ARGR(c, r)
 453#define XFS_BTREE_TRACE_CURSOR(c, t)
 454
 455#endif  /* __XFS_BTREE_H__ */
 456
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