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        const struct xfs_buf_ops        *buf_ops;
 192
 193#ifdef DEBUG
 194        /* check that k1 is lower than k2 */
 195        int     (*keys_inorder)(struct xfs_btree_cur *cur,
 196                                union xfs_btree_key *k1,
 197                                union xfs_btree_key *k2);
 198
 199        /* check that r1 is lower than r2 */
 200        int     (*recs_inorder)(struct xfs_btree_cur *cur,
 201                                union xfs_btree_rec *r1,
 202                                union xfs_btree_rec *r2);
 203#endif
 204};
 205
 206/*
 207 * Reasons for the update_lastrec method to be called.
 208 */
 209#define LASTREC_UPDATE  0
 210#define LASTREC_INSREC  1
 211#define LASTREC_DELREC  2
 212
 213
 214/*
 215 * Btree cursor structure.
 216 * This collects all information needed by the btree code in one place.
 217 */
 218typedef struct xfs_btree_cur
 219{
 220        struct xfs_trans        *bc_tp; /* transaction we're in, if any */
 221        struct xfs_mount        *bc_mp; /* file system mount struct */
 222        const struct xfs_btree_ops *bc_ops;
 223        uint                    bc_flags; /* btree features - below */
 224        union {
 225                xfs_alloc_rec_incore_t  a;
 226                xfs_bmbt_irec_t         b;
 227                xfs_inobt_rec_incore_t  i;
 228        }               bc_rec;         /* current insert/search record value */
 229        struct xfs_buf  *bc_bufs[XFS_BTREE_MAXLEVELS];  /* buf ptr per level */
 230        int             bc_ptrs[XFS_BTREE_MAXLEVELS];   /* key/record # */
 231        __uint8_t       bc_ra[XFS_BTREE_MAXLEVELS];     /* readahead bits */
 232#define XFS_BTCUR_LEFTRA        1       /* left sibling has been read-ahead */
 233#define XFS_BTCUR_RIGHTRA       2       /* right sibling has been read-ahead */
 234        __uint8_t       bc_nlevels;     /* number of levels in the tree */
 235        __uint8_t       bc_blocklog;    /* log2(blocksize) of btree blocks */
 236        xfs_btnum_t     bc_btnum;       /* identifies which btree type */
 237        union {
 238                struct {                        /* needed for BNO, CNT, INO */
 239                        struct xfs_buf  *agbp;  /* agf/agi buffer pointer */
 240                        xfs_agnumber_t  agno;   /* ag number */
 241                } a;
 242                struct {                        /* needed for BMAP */
 243                        struct xfs_inode *ip;   /* pointer to our inode */
 244                        struct xfs_bmap_free *flist;    /* list to free after */
 245                        xfs_fsblock_t   firstblock;     /* 1st blk allocated */
 246                        int             allocated;      /* count of alloced */
 247                        short           forksize;       /* fork's inode space */
 248                        char            whichfork;      /* data or attr fork */
 249                        char            flags;          /* flags */
 250#define XFS_BTCUR_BPRV_WASDEL   1                       /* was delayed */
 251                } b;
 252        }               bc_private;     /* per-btree type data */
 253} xfs_btree_cur_t;
 254
 255/* cursor flags */
 256#define XFS_BTREE_LONG_PTRS             (1<<0)  /* pointers are 64bits long */
 257#define XFS_BTREE_ROOT_IN_INODE         (1<<1)  /* root may be variable size */
 258#define XFS_BTREE_LASTREC_UPDATE        (1<<2)  /* track last rec externally */
 259
 260
 261#define XFS_BTREE_NOERROR       0
 262#define XFS_BTREE_ERROR         1
 263
 264/*
 265 * Convert from buffer to btree block header.
 266 */
 267#define XFS_BUF_TO_BLOCK(bp)    ((struct xfs_btree_block *)((bp)->b_addr))
 268
 269
 270/*
 271 * Check that block header is ok.
 272 */
 273int
 274xfs_btree_check_block(
 275        struct xfs_btree_cur    *cur,   /* btree cursor */
 276        struct xfs_btree_block  *block, /* generic btree block pointer */
 277        int                     level,  /* level of the btree block */
 278        struct xfs_buf          *bp);   /* buffer containing block, if any */
 279
 280/*
 281 * Check that (long) pointer is ok.
 282 */
 283int                                     /* error (0 or EFSCORRUPTED) */
 284xfs_btree_check_lptr(
 285        struct xfs_btree_cur    *cur,   /* btree cursor */
 286        xfs_dfsbno_t            ptr,    /* btree block disk address */
 287        int                     level); /* btree block level */
 288
 289/*
 290 * Delete the btree cursor.
 291 */
 292void
 293xfs_btree_del_cursor(
 294        xfs_btree_cur_t         *cur,   /* btree cursor */
 295        int                     error); /* del because of error */
 296
 297/*
 298 * Duplicate the btree cursor.
 299 * Allocate a new one, copy the record, re-get the buffers.
 300 */
 301int                                     /* error */
 302xfs_btree_dup_cursor(
 303        xfs_btree_cur_t         *cur,   /* input cursor */
 304        xfs_btree_cur_t         **ncur);/* output cursor */
 305
 306/*
 307 * Get a buffer for the block, return it with no data read.
 308 * Long-form addressing.
 309 */
 310struct xfs_buf *                                /* buffer for fsbno */
 311xfs_btree_get_bufl(
 312        struct xfs_mount        *mp,    /* file system mount point */
 313        struct xfs_trans        *tp,    /* transaction pointer */
 314        xfs_fsblock_t           fsbno,  /* file system block number */
 315        uint                    lock);  /* lock flags for get_buf */
 316
 317/*
 318 * Get a buffer for the block, return it with no data read.
 319 * Short-form addressing.
 320 */
 321struct xfs_buf *                                /* buffer for agno/agbno */
 322xfs_btree_get_bufs(
 323        struct xfs_mount        *mp,    /* file system mount point */
 324        struct xfs_trans        *tp,    /* transaction pointer */
 325        xfs_agnumber_t          agno,   /* allocation group number */
 326        xfs_agblock_t           agbno,  /* allocation group block number */
 327        uint                    lock);  /* lock flags for get_buf */
 328
 329/*
 330 * Check for the cursor referring to the last block at the given level.
 331 */
 332int                                     /* 1=is last block, 0=not last block */
 333xfs_btree_islastblock(
 334        xfs_btree_cur_t         *cur,   /* btree cursor */
 335        int                     level); /* level to check */
 336
 337/*
 338 * Compute first and last byte offsets for the fields given.
 339 * Interprets the offsets table, which contains struct field offsets.
 340 */
 341void
 342xfs_btree_offsets(
 343        __int64_t               fields, /* bitmask of fields */
 344        const short             *offsets,/* table of field offsets */
 345        int                     nbits,  /* number of bits to inspect */
 346        int                     *first, /* output: first byte offset */
 347        int                     *last); /* output: last byte offset */
 348
 349/*
 350 * Get a buffer for the block, return it read in.
 351 * Long-form addressing.
 352 */
 353int                                     /* error */
 354xfs_btree_read_bufl(
 355        struct xfs_mount        *mp,    /* file system mount point */
 356        struct xfs_trans        *tp,    /* transaction pointer */
 357        xfs_fsblock_t           fsbno,  /* file system block number */
 358        uint                    lock,   /* lock flags for read_buf */
 359        struct xfs_buf          **bpp,  /* buffer for fsbno */
 360        int                     refval, /* ref count value for buffer */
 361        const struct xfs_buf_ops *ops);
 362
 363/*
 364 * Read-ahead the block, don't wait for it, don't return a buffer.
 365 * Long-form addressing.
 366 */
 367void                                    /* error */
 368xfs_btree_reada_bufl(
 369        struct xfs_mount        *mp,    /* file system mount point */
 370        xfs_fsblock_t           fsbno,  /* file system block number */
 371        xfs_extlen_t            count,  /* count of filesystem blocks */
 372        const struct xfs_buf_ops *ops);
 373
 374/*
 375 * Read-ahead the block, don't wait for it, don't return a buffer.
 376 * Short-form addressing.
 377 */
 378void                                    /* error */
 379xfs_btree_reada_bufs(
 380        struct xfs_mount        *mp,    /* file system mount point */
 381        xfs_agnumber_t          agno,   /* allocation group number */
 382        xfs_agblock_t           agbno,  /* allocation group block number */
 383        xfs_extlen_t            count,  /* count of filesystem blocks */
 384        const struct xfs_buf_ops *ops);
 385
 386/*
 387 * Initialise a new btree block header
 388 */
 389void
 390xfs_btree_init_block(
 391        struct xfs_mount *mp,
 392        struct xfs_buf  *bp,
 393        __u32           magic,
 394        __u16           level,
 395        __u16           numrecs,
 396        unsigned int    flags);
 397
 398/*
 399 * Common btree core entry points.
 400 */
 401int xfs_btree_increment(struct xfs_btree_cur *, int, int *);
 402int xfs_btree_decrement(struct xfs_btree_cur *, int, int *);
 403int xfs_btree_lookup(struct xfs_btree_cur *, xfs_lookup_t, int *);
 404int xfs_btree_update(struct xfs_btree_cur *, union xfs_btree_rec *);
 405int xfs_btree_new_iroot(struct xfs_btree_cur *, int *, int *);
 406int xfs_btree_insert(struct xfs_btree_cur *, int *);
 407int xfs_btree_delete(struct xfs_btree_cur *, int *);
 408int xfs_btree_get_rec(struct xfs_btree_cur *, union xfs_btree_rec **, int *);
 409
 410/*
 411 * Internal btree helpers also used by xfs_bmap.c.
 412 */
 413void xfs_btree_log_block(struct xfs_btree_cur *, struct xfs_buf *, int);
 414void xfs_btree_log_recs(struct xfs_btree_cur *, struct xfs_buf *, int, int);
 415
 416/*
 417 * Helpers.
 418 */
 419static inline int xfs_btree_get_numrecs(struct xfs_btree_block *block)
 420{
 421        return be16_to_cpu(block->bb_numrecs);
 422}
 423
 424static inline void xfs_btree_set_numrecs(struct xfs_btree_block *block,
 425                __uint16_t numrecs)
 426{
 427        block->bb_numrecs = cpu_to_be16(numrecs);
 428}
 429
 430static inline int xfs_btree_get_level(struct xfs_btree_block *block)
 431{
 432        return be16_to_cpu(block->bb_level);
 433}
 434
 435
 436/*
 437 * Min and max functions for extlen, agblock, fileoff, and filblks types.
 438 */
 439#define XFS_EXTLEN_MIN(a,b)     min_t(xfs_extlen_t, (a), (b))
 440#define XFS_EXTLEN_MAX(a,b)     max_t(xfs_extlen_t, (a), (b))
 441#define XFS_AGBLOCK_MIN(a,b)    min_t(xfs_agblock_t, (a), (b))
 442#define XFS_AGBLOCK_MAX(a,b)    max_t(xfs_agblock_t, (a), (b))
 443#define XFS_FILEOFF_MIN(a,b)    min_t(xfs_fileoff_t, (a), (b))
 444#define XFS_FILEOFF_MAX(a,b)    max_t(xfs_fileoff_t, (a), (b))
 445#define XFS_FILBLKS_MIN(a,b)    min_t(xfs_filblks_t, (a), (b))
 446#define XFS_FILBLKS_MAX(a,b)    max_t(xfs_filblks_t, (a), (b))
 447
 448#define XFS_FSB_SANITY_CHECK(mp,fsb)    \
 449        (XFS_FSB_TO_AGNO(mp, fsb) < mp->m_sb.sb_agcount && \
 450                XFS_FSB_TO_AGBNO(mp, fsb) < mp->m_sb.sb_agblocks)
 451
 452/*
 453 * Trace hooks.  Currently not implemented as they need to be ported
 454 * over to the generic tracing functionality, which is some effort.
 455 *
 456 * i,j = integer (32 bit)
 457 * b = btree block buffer (xfs_buf_t)
 458 * p = btree ptr
 459 * r = btree record
 460 * k = btree key
 461 */
 462#define XFS_BTREE_TRACE_ARGBI(c, b, i)
 463#define XFS_BTREE_TRACE_ARGBII(c, b, i, j)
 464#define XFS_BTREE_TRACE_ARGI(c, i)
 465#define XFS_BTREE_TRACE_ARGIPK(c, i, p, s)
 466#define XFS_BTREE_TRACE_ARGIPR(c, i, p, r)
 467#define XFS_BTREE_TRACE_ARGIK(c, i, k)
 468#define XFS_BTREE_TRACE_ARGR(c, r)
 469#define XFS_BTREE_TRACE_CURSOR(c, t)
 470
 471#endif  /* __XFS_BTREE_H__ */
 472
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