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 the
  46 * 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 the size
  49 * macros below.  Never use sizeof(xfs_btree_block).
  50 *
  51 * The blkno, crc, lsn, owner and uuid fields are only available in filesystems
  52 * with the crc feature bit, and all accesses to them must be conditional on
  53 * that flag.
  54 */
  55struct xfs_btree_block {
  56        __be32          bb_magic;       /* magic number for block type */
  57        __be16          bb_level;       /* 0 is a leaf */
  58        __be16          bb_numrecs;     /* current # of data records */
  59        union {
  60                struct {
  61                        __be32          bb_leftsib;
  62                        __be32          bb_rightsib;
  63
  64                        __be64          bb_blkno;
  65                        __be64          bb_lsn;
  66                        uuid_t          bb_uuid;
  67                        __be32          bb_owner;
  68                        __le32          bb_crc;
  69                } s;                    /* short form pointers */
  70                struct  {
  71                        __be64          bb_leftsib;
  72                        __be64          bb_rightsib;
  73
  74                        __be64          bb_blkno;
  75                        __be64          bb_lsn;
  76                        uuid_t          bb_uuid;
  77                        __be64          bb_owner;
  78                        __le32          bb_crc;
  79                        __be32          bb_pad; /* padding for alignment */
  80                } l;                    /* long form pointers */
  81        } bb_u;                         /* rest */
  82};
  83
  84#define XFS_BTREE_SBLOCK_LEN    16      /* size of a short form block */
  85#define XFS_BTREE_LBLOCK_LEN    24      /* size of a long form block */
  86
  87/* sizes of CRC enabled btree blocks */
  88#define XFS_BTREE_SBLOCK_CRC_LEN        (XFS_BTREE_SBLOCK_LEN + 40)
  89#define XFS_BTREE_LBLOCK_CRC_LEN        (XFS_BTREE_LBLOCK_LEN + 48)
  90
  91
  92#define XFS_BTREE_SBLOCK_CRC_OFF \
  93        offsetof(struct xfs_btree_block, bb_u.s.bb_crc)
  94#define XFS_BTREE_LBLOCK_CRC_OFF \
  95        offsetof(struct xfs_btree_block, bb_u.l.bb_crc)
  96
  97
  98/*
  99 * Generic key, ptr and record wrapper structures.
 100 *
 101 * These are disk format structures, and are converted where necessary
 102 * by the btree specific code that needs to interpret them.
 103 */
 104union xfs_btree_ptr {
 105        __be32                  s;      /* short form ptr */
 106        __be64                  l;      /* long form ptr */
 107};
 108
 109union xfs_btree_key {
 110        xfs_bmbt_key_t          bmbt;
 111        xfs_bmdr_key_t          bmbr;   /* bmbt root block */
 112        xfs_alloc_key_t         alloc;
 113        xfs_inobt_key_t         inobt;
 114};
 115
 116union xfs_btree_rec {
 117        xfs_bmbt_rec_t          bmbt;
 118        xfs_bmdr_rec_t          bmbr;   /* bmbt root block */
 119        xfs_alloc_rec_t         alloc;
 120        xfs_inobt_rec_t         inobt;
 121};
 122
 123/*
 124 * For logging record fields.
 125 */
 126#define XFS_BB_MAGIC            0x01
 127#define XFS_BB_LEVEL            0x02
 128#define XFS_BB_NUMRECS          0x04
 129#define XFS_BB_LEFTSIB          0x08
 130#define XFS_BB_RIGHTSIB         0x10
 131#define XFS_BB_BLKNO            0x20
 132#define XFS_BB_NUM_BITS         5
 133#define XFS_BB_ALL_BITS         ((1 << XFS_BB_NUM_BITS) - 1)
 134#define XFS_BB_NUM_BITS_CRC     8
 135#define XFS_BB_ALL_BITS_CRC     ((1 << XFS_BB_NUM_BITS_CRC) - 1)
 136
 137/*
 138 * Generic stats interface
 139 */
 140#define __XFS_BTREE_STATS_INC(type, stat) \
 141        XFS_STATS_INC(xs_ ## type ## _2_ ## stat)
 142#define XFS_BTREE_STATS_INC(cur, stat)  \
 143do {    \
 144        switch (cur->bc_btnum) {  \
 145        case XFS_BTNUM_BNO: __XFS_BTREE_STATS_INC(abtb, stat); break;   \
 146        case XFS_BTNUM_CNT: __XFS_BTREE_STATS_INC(abtc, stat); break;   \
 147        case XFS_BTNUM_BMAP: __XFS_BTREE_STATS_INC(bmbt, stat); break;  \
 148        case XFS_BTNUM_INO: __XFS_BTREE_STATS_INC(ibt, stat); break;    \
 149        case XFS_BTNUM_MAX: ASSERT(0); /* fucking gcc */ ; break;       \
 150        }       \
 151} while (0)
 152
 153#define __XFS_BTREE_STATS_ADD(type, stat, val) \
 154        XFS_STATS_ADD(xs_ ## type ## _2_ ## stat, val)
 155#define XFS_BTREE_STATS_ADD(cur, stat, val)  \
 156do {    \
 157        switch (cur->bc_btnum) {  \
 158        case XFS_BTNUM_BNO: __XFS_BTREE_STATS_ADD(abtb, stat, val); break; \
 159        case XFS_BTNUM_CNT: __XFS_BTREE_STATS_ADD(abtc, stat, val); break; \
 160        case XFS_BTNUM_BMAP: __XFS_BTREE_STATS_ADD(bmbt, stat, val); break; \
 161        case XFS_BTNUM_INO: __XFS_BTREE_STATS_ADD(ibt, stat, val); break; \
 162        case XFS_BTNUM_MAX: ASSERT(0); /* fucking gcc */ ; break;       \
 163        }       \
 164} while (0)
 165
 166#define XFS_BTREE_MAXLEVELS     8       /* max of all btrees */
 167
 168struct xfs_btree_ops {
 169        /* size of the key and record structures */
 170        size_t  key_len;
 171        size_t  rec_len;
 172
 173        /* cursor operations */
 174        struct xfs_btree_cur *(*dup_cursor)(struct xfs_btree_cur *);
 175        void    (*update_cursor)(struct xfs_btree_cur *src,
 176                                 struct xfs_btree_cur *dst);
 177
 178        /* update btree root pointer */
 179        void    (*set_root)(struct xfs_btree_cur *cur,
 180                            union xfs_btree_ptr *nptr, int level_change);
 181
 182        /* block allocation / freeing */
 183        int     (*alloc_block)(struct xfs_btree_cur *cur,
 184                               union xfs_btree_ptr *start_bno,
 185                               union xfs_btree_ptr *new_bno,
 186                               int length, int *stat);
 187        int     (*free_block)(struct xfs_btree_cur *cur, struct xfs_buf *bp);
 188
 189        /* update last record information */
 190        void    (*update_lastrec)(struct xfs_btree_cur *cur,
 191                                  struct xfs_btree_block *block,
 192                                  union xfs_btree_rec *rec,
 193                                  int ptr, int reason);
 194
 195        /* records in block/level */
 196        int     (*get_minrecs)(struct xfs_btree_cur *cur, int level);
 197        int     (*get_maxrecs)(struct xfs_btree_cur *cur, int level);
 198
 199        /* records on disk.  Matter for the root in inode case. */
 200        int     (*get_dmaxrecs)(struct xfs_btree_cur *cur, int level);
 201
 202        /* init values of btree structures */
 203        void    (*init_key_from_rec)(union xfs_btree_key *key,
 204                                     union xfs_btree_rec *rec);
 205        void    (*init_rec_from_key)(union xfs_btree_key *key,
 206                                     union xfs_btree_rec *rec);
 207        void    (*init_rec_from_cur)(struct xfs_btree_cur *cur,
 208                                     union xfs_btree_rec *rec);
 209        void    (*init_ptr_from_cur)(struct xfs_btree_cur *cur,
 210                                     union xfs_btree_ptr *ptr);
 211
 212        /* difference between key value and cursor value */
 213        __int64_t (*key_diff)(struct xfs_btree_cur *cur,
 214                              union xfs_btree_key *key);
 215
 216        const struct xfs_buf_ops        *buf_ops;
 217
 218#if defined(DEBUG) || defined(XFS_WARN)
 219        /* check that k1 is lower than k2 */
 220        int     (*keys_inorder)(struct xfs_btree_cur *cur,
 221                                union xfs_btree_key *k1,
 222                                union xfs_btree_key *k2);
 223
 224        /* check that r1 is lower than r2 */
 225        int     (*recs_inorder)(struct xfs_btree_cur *cur,
 226                                union xfs_btree_rec *r1,
 227                                union xfs_btree_rec *r2);
 228#endif
 229};
 230
 231/*
 232 * Reasons for the update_lastrec method to be called.
 233 */
 234#define LASTREC_UPDATE  0
 235#define LASTREC_INSREC  1
 236#define LASTREC_DELREC  2
 237
 238
 239/*
 240 * Btree cursor structure.
 241 * This collects all information needed by the btree code in one place.
 242 */
 243typedef struct xfs_btree_cur
 244{
 245        struct xfs_trans        *bc_tp; /* transaction we're in, if any */
 246        struct xfs_mount        *bc_mp; /* file system mount struct */
 247        const struct xfs_btree_ops *bc_ops;
 248        uint                    bc_flags; /* btree features - below */
 249        union {
 250                xfs_alloc_rec_incore_t  a;
 251                xfs_bmbt_irec_t         b;
 252                xfs_inobt_rec_incore_t  i;
 253        }               bc_rec;         /* current insert/search record value */
 254        struct xfs_buf  *bc_bufs[XFS_BTREE_MAXLEVELS];  /* buf ptr per level */
 255        int             bc_ptrs[XFS_BTREE_MAXLEVELS];   /* key/record # */
 256        __uint8_t       bc_ra[XFS_BTREE_MAXLEVELS];     /* readahead bits */
 257#define XFS_BTCUR_LEFTRA        1       /* left sibling has been read-ahead */
 258#define XFS_BTCUR_RIGHTRA       2       /* right sibling has been read-ahead */
 259        __uint8_t       bc_nlevels;     /* number of levels in the tree */
 260        __uint8_t       bc_blocklog;    /* log2(blocksize) of btree blocks */
 261        xfs_btnum_t     bc_btnum;       /* identifies which btree type */
 262        union {
 263                struct {                        /* needed for BNO, CNT, INO */
 264                        struct xfs_buf  *agbp;  /* agf/agi buffer pointer */
 265                        xfs_agnumber_t  agno;   /* ag number */
 266                } a;
 267                struct {                        /* needed for BMAP */
 268                        struct xfs_inode *ip;   /* pointer to our inode */
 269                        struct xfs_bmap_free *flist;    /* list to free after */
 270                        xfs_fsblock_t   firstblock;     /* 1st blk allocated */
 271                        int             allocated;      /* count of alloced */
 272                        short           forksize;       /* fork's inode space */
 273                        char            whichfork;      /* data or attr fork */
 274                        char            flags;          /* flags */
 275#define XFS_BTCUR_BPRV_WASDEL   1                       /* was delayed */
 276                } b;
 277        }               bc_private;     /* per-btree type data */
 278} xfs_btree_cur_t;
 279
 280/* cursor flags */
 281#define XFS_BTREE_LONG_PTRS             (1<<0)  /* pointers are 64bits long */
 282#define XFS_BTREE_ROOT_IN_INODE         (1<<1)  /* root may be variable size */
 283#define XFS_BTREE_LASTREC_UPDATE        (1<<2)  /* track last rec externally */
 284#define XFS_BTREE_CRC_BLOCKS            (1<<3)  /* uses extended btree blocks */
 285
 286
 287#define XFS_BTREE_NOERROR       0
 288#define XFS_BTREE_ERROR         1
 289
 290/*
 291 * Convert from buffer to btree block header.
 292 */
 293#define XFS_BUF_TO_BLOCK(bp)    ((struct xfs_btree_block *)((bp)->b_addr))
 294
 295
 296/*
 297 * Check that block header is ok.
 298 */
 299int
 300xfs_btree_check_block(
 301        struct xfs_btree_cur    *cur,   /* btree cursor */
 302        struct xfs_btree_block  *block, /* generic btree block pointer */
 303        int                     level,  /* level of the btree block */
 304        struct xfs_buf          *bp);   /* buffer containing block, if any */
 305
 306/*
 307 * Check that (long) pointer is ok.
 308 */
 309int                                     /* error (0 or EFSCORRUPTED) */
 310xfs_btree_check_lptr(
 311        struct xfs_btree_cur    *cur,   /* btree cursor */
 312        xfs_dfsbno_t            ptr,    /* btree block disk address */
 313        int                     level); /* btree block level */
 314
 315/*
 316 * Delete the btree cursor.
 317 */
 318void
 319xfs_btree_del_cursor(
 320        xfs_btree_cur_t         *cur,   /* btree cursor */
 321        int                     error); /* del because of error */
 322
 323/*
 324 * Duplicate the btree cursor.
 325 * Allocate a new one, copy the record, re-get the buffers.
 326 */
 327int                                     /* error */
 328xfs_btree_dup_cursor(
 329        xfs_btree_cur_t         *cur,   /* input cursor */
 330        xfs_btree_cur_t         **ncur);/* output cursor */
 331
 332/*
 333 * Get a buffer for the block, return it with no data read.
 334 * Long-form addressing.
 335 */
 336struct xfs_buf *                                /* buffer for fsbno */
 337xfs_btree_get_bufl(
 338        struct xfs_mount        *mp,    /* file system mount point */
 339        struct xfs_trans        *tp,    /* transaction pointer */
 340        xfs_fsblock_t           fsbno,  /* file system block number */
 341        uint                    lock);  /* lock flags for get_buf */
 342
 343/*
 344 * Get a buffer for the block, return it with no data read.
 345 * Short-form addressing.
 346 */
 347struct xfs_buf *                                /* buffer for agno/agbno */
 348xfs_btree_get_bufs(
 349        struct xfs_mount        *mp,    /* file system mount point */
 350        struct xfs_trans        *tp,    /* transaction pointer */
 351        xfs_agnumber_t          agno,   /* allocation group number */
 352        xfs_agblock_t           agbno,  /* allocation group block number */
 353        uint                    lock);  /* lock flags for get_buf */
 354
 355/*
 356 * Check for the cursor referring to the last block at the given level.
 357 */
 358int                                     /* 1=is last block, 0=not last block */
 359xfs_btree_islastblock(
 360        xfs_btree_cur_t         *cur,   /* btree cursor */
 361        int                     level); /* level to check */
 362
 363/*
 364 * Compute first and last byte offsets for the fields given.
 365 * Interprets the offsets table, which contains struct field offsets.
 366 */
 367void
 368xfs_btree_offsets(
 369        __int64_t               fields, /* bitmask of fields */
 370        const short             *offsets,/* table of field offsets */
 371        int                     nbits,  /* number of bits to inspect */
 372        int                     *first, /* output: first byte offset */
 373        int                     *last); /* output: last byte offset */
 374
 375/*
 376 * Get a buffer for the block, return it read in.
 377 * Long-form addressing.
 378 */
 379int                                     /* error */
 380xfs_btree_read_bufl(
 381        struct xfs_mount        *mp,    /* file system mount point */
 382        struct xfs_trans        *tp,    /* transaction pointer */
 383        xfs_fsblock_t           fsbno,  /* file system block number */
 384        uint                    lock,   /* lock flags for read_buf */
 385        struct xfs_buf          **bpp,  /* buffer for fsbno */
 386        int                     refval, /* ref count value for buffer */
 387        const struct xfs_buf_ops *ops);
 388
 389/*
 390 * Read-ahead the block, don't wait for it, don't return a buffer.
 391 * Long-form addressing.
 392 */
 393void                                    /* error */
 394xfs_btree_reada_bufl(
 395        struct xfs_mount        *mp,    /* file system mount point */
 396        xfs_fsblock_t           fsbno,  /* file system block number */
 397        xfs_extlen_t            count,  /* count of filesystem blocks */
 398        const struct xfs_buf_ops *ops);
 399
 400/*
 401 * Read-ahead the block, don't wait for it, don't return a buffer.
 402 * Short-form addressing.
 403 */
 404void                                    /* error */
 405xfs_btree_reada_bufs(
 406        struct xfs_mount        *mp,    /* file system mount point */
 407        xfs_agnumber_t          agno,   /* allocation group number */
 408        xfs_agblock_t           agbno,  /* allocation group block number */
 409        xfs_extlen_t            count,  /* count of filesystem blocks */
 410        const struct xfs_buf_ops *ops);
 411
 412/*
 413 * Initialise a new btree block header
 414 */
 415void
 416xfs_btree_init_block(
 417        struct xfs_mount *mp,
 418        struct xfs_buf  *bp,
 419        __u32           magic,
 420        __u16           level,
 421        __u16           numrecs,
 422        __u64           owner,
 423        unsigned int    flags);
 424
 425void
 426xfs_btree_init_block_int(
 427        struct xfs_mount        *mp,
 428        struct xfs_btree_block  *buf,
 429        xfs_daddr_t             blkno,
 430        __u32                   magic,
 431        __u16                   level,
 432        __u16                   numrecs,
 433        __u64                   owner,
 434        unsigned int            flags);
 435
 436/*
 437 * Common btree core entry points.
 438 */
 439int xfs_btree_increment(struct xfs_btree_cur *, int, int *);
 440int xfs_btree_decrement(struct xfs_btree_cur *, int, int *);
 441int xfs_btree_lookup(struct xfs_btree_cur *, xfs_lookup_t, int *);
 442int xfs_btree_update(struct xfs_btree_cur *, union xfs_btree_rec *);
 443int xfs_btree_new_iroot(struct xfs_btree_cur *, int *, int *);
 444int xfs_btree_insert(struct xfs_btree_cur *, int *);
 445int xfs_btree_delete(struct xfs_btree_cur *, int *);
 446int xfs_btree_get_rec(struct xfs_btree_cur *, union xfs_btree_rec **, int *);
 447
 448/*
 449 * btree block CRC helpers
 450 */
 451void xfs_btree_lblock_calc_crc(struct xfs_buf *);
 452bool xfs_btree_lblock_verify_crc(struct xfs_buf *);
 453void xfs_btree_sblock_calc_crc(struct xfs_buf *);
 454bool xfs_btree_sblock_verify_crc(struct xfs_buf *);
 455
 456/*
 457 * Internal btree helpers also used by xfs_bmap.c.
 458 */
 459void xfs_btree_log_block(struct xfs_btree_cur *, struct xfs_buf *, int);
 460void xfs_btree_log_recs(struct xfs_btree_cur *, struct xfs_buf *, int, int);
 461
 462/*
 463 * Helpers.
 464 */
 465static inline int xfs_btree_get_numrecs(struct xfs_btree_block *block)
 466{
 467        return be16_to_cpu(block->bb_numrecs);
 468}
 469
 470static inline void xfs_btree_set_numrecs(struct xfs_btree_block *block,
 471                __uint16_t numrecs)
 472{
 473        block->bb_numrecs = cpu_to_be16(numrecs);
 474}
 475
 476static inline int xfs_btree_get_level(struct xfs_btree_block *block)
 477{
 478        return be16_to_cpu(block->bb_level);
 479}
 480
 481
 482/*
 483 * Min and max functions for extlen, agblock, fileoff, and filblks types.
 484 */
 485#define XFS_EXTLEN_MIN(a,b)     min_t(xfs_extlen_t, (a), (b))
 486#define XFS_EXTLEN_MAX(a,b)     max_t(xfs_extlen_t, (a), (b))
 487#define XFS_AGBLOCK_MIN(a,b)    min_t(xfs_agblock_t, (a), (b))
 488#define XFS_AGBLOCK_MAX(a,b)    max_t(xfs_agblock_t, (a), (b))
 489#define XFS_FILEOFF_MIN(a,b)    min_t(xfs_fileoff_t, (a), (b))
 490#define XFS_FILEOFF_MAX(a,b)    max_t(xfs_fileoff_t, (a), (b))
 491#define XFS_FILBLKS_MIN(a,b)    min_t(xfs_filblks_t, (a), (b))
 492#define XFS_FILBLKS_MAX(a,b)    max_t(xfs_filblks_t, (a), (b))
 493
 494#define XFS_FSB_SANITY_CHECK(mp,fsb)    \
 495        (XFS_FSB_TO_AGNO(mp, fsb) < mp->m_sb.sb_agcount && \
 496                XFS_FSB_TO_AGBNO(mp, fsb) < mp->m_sb.sb_agblocks)
 497
 498/*
 499 * Trace hooks.  Currently not implemented as they need to be ported
 500 * over to the generic tracing functionality, which is some effort.
 501 *
 502 * i,j = integer (32 bit)
 503 * b = btree block buffer (xfs_buf_t)
 504 * p = btree ptr
 505 * r = btree record
 506 * k = btree key
 507 */
 508#define XFS_BTREE_TRACE_ARGBI(c, b, i)
 509#define XFS_BTREE_TRACE_ARGBII(c, b, i, j)
 510#define XFS_BTREE_TRACE_ARGI(c, i)
 511#define XFS_BTREE_TRACE_ARGIPK(c, i, p, s)
 512#define XFS_BTREE_TRACE_ARGIPR(c, i, p, r)
 513#define XFS_BTREE_TRACE_ARGIK(c, i, k)
 514#define XFS_BTREE_TRACE_ARGR(c, r)
 515#define XFS_BTREE_TRACE_CURSOR(c, t)
 516
 517#endif  /* __XFS_BTREE_H__ */
 518
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