fs/xfs/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_bmap_free;
  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  * 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  */
  51 struct 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  */
  77 union xfs_btree_ptr {
  78         __be32                  s;      /* short form ptr */
  79         __be64                  l;      /* long form ptr */
  80 };
  81
  82 union 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
  89 union 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  */
 110 extern 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)  \
 118 do {    \
 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)  \
 131 do {    \
 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
 143 struct 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         int     (*kill_root)(struct xfs_btree_cur *cur, struct xfs_buf *bp,
 157                                 int level, union xfs_btree_ptr *newroot);
 158
 159         /* block allocation / freeing */
 160         int     (*alloc_block)(struct xfs_btree_cur *cur,
 161                                union xfs_btree_ptr *start_bno,
 162                                union xfs_btree_ptr *new_bno,
 163                                int length, int *stat);
 164         int     (*free_block)(struct xfs_btree_cur *cur, struct xfs_buf *bp);
 165
 166         /* update last record information */
 167         void    (*update_lastrec)(struct xfs_btree_cur *cur,
 168                                   struct xfs_btree_block *block,
 169                                   union xfs_btree_rec *rec,
 170                                   int ptr, int reason);
 171
 172         /* records in block/level */
 173         int     (*get_minrecs)(struct xfs_btree_cur *cur, int level);
 174         int     (*get_maxrecs)(struct xfs_btree_cur *cur, int level);
 175
 176         /* records on disk.  Matter for the root in inode case. */
 177         int     (*get_dmaxrecs)(struct xfs_btree_cur *cur, int level);
 178
 179         /* init values of btree structures */
 180         void    (*init_key_from_rec)(union xfs_btree_key *key,
 181                                      union xfs_btree_rec *rec);
 182         void    (*init_rec_from_key)(union xfs_btree_key *key,
 183                                      union xfs_btree_rec *rec);
 184         void    (*init_rec_from_cur)(struct xfs_btree_cur *cur,
 185                                      union xfs_btree_rec *rec);
 186         void    (*init_ptr_from_cur)(struct xfs_btree_cur *cur,
 187                                      union xfs_btree_ptr *ptr);
 188
 189         /* difference between key value and cursor value */
 190         __int64_t (*key_diff)(struct xfs_btree_cur *cur,
 191                               union xfs_btree_key *key);
 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         /* btree tracing */
 206 #ifdef XFS_BTREE_TRACE
 207         void            (*trace_enter)(struct xfs_btree_cur *, const char *,
 208                                        char *, int, int, __psunsigned_t,
 209                                        __psunsigned_t, __psunsigned_t,
 210                                        __psunsigned_t, __psunsigned_t,
 211                                        __psunsigned_t, __psunsigned_t,
 212                                        __psunsigned_t, __psunsigned_t,
 213                                        __psunsigned_t, __psunsigned_t);
 214         void            (*trace_cursor)(struct xfs_btree_cur *, __uint32_t *,
 215                                         __uint64_t *, __uint64_t *);
 216         void            (*trace_key)(struct xfs_btree_cur *,
 217                                      union xfs_btree_key *, __uint64_t *,
 218                                      __uint64_t *);
 219         void            (*trace_record)(struct xfs_btree_cur *,
 220                                         union xfs_btree_rec *, __uint64_t *,
 221                                         __uint64_t *, __uint64_t *);
 222 #endif
 223 };
 224
 225 /*
 226  * Reasons for the update_lastrec method to be called.
 227  */
 228 #define LASTREC_UPDATE  0
 229 #define LASTREC_INSREC  1
 230 #define LASTREC_DELREC  2
 231
 232
 233 /*
 234  * Btree cursor structure.
 235  * This collects all information needed by the btree code in one place.
 236  */
 237 typedef struct xfs_btree_cur
 238 {
 239         struct xfs_trans        *bc_tp; /* transaction we're in, if any */
 240         struct xfs_mount        *bc_mp; /* file system mount struct */
 241         const struct xfs_btree_ops *bc_ops;
 242         uint                    bc_flags; /* btree features - below */
 243         union {
 244                 xfs_alloc_rec_incore_t  a;
 245                 xfs_bmbt_irec_t         b;
 246                 xfs_inobt_rec_incore_t  i;
 247         }               bc_rec;         /* current insert/search record value */
 248         struct xfs_buf  *bc_bufs[XFS_BTREE_MAXLEVELS];  /* buf ptr per level */
 249         int             bc_ptrs[XFS_BTREE_MAXLEVELS];   /* key/record # */
 250         __uint8_t       bc_ra[XFS_BTREE_MAXLEVELS];     /* readahead bits */
 251 #define XFS_BTCUR_LEFTRA        1       /* left sibling has been read-ahead */
 252 #define XFS_BTCUR_RIGHTRA       2       /* right sibling has been read-ahead */
 253         __uint8_t       bc_nlevels;     /* number of levels in the tree */
 254         __uint8_t       bc_blocklog;    /* log2(blocksize) of btree blocks */
 255         xfs_btnum_t     bc_btnum;       /* identifies which btree type */
 256         union {
 257                 struct {                        /* needed for BNO, CNT, INO */
 258                         struct xfs_buf  *agbp;  /* agf/agi buffer pointer */
 259                         xfs_agnumber_t  agno;   /* ag number */
 260                 } a;
 261                 struct {                        /* needed for BMAP */
 262                         struct xfs_inode *ip;   /* pointer to our inode */
 263                         struct xfs_bmap_free *flist;    /* list to free after */
 264                         xfs_fsblock_t   firstblock;     /* 1st blk allocated */
 265                         int             allocated;      /* count of alloced */
 266                         short           forksize;       /* fork's inode space */
 267                         char            whichfork;      /* data or attr fork */
 268                         char            flags;          /* flags */
 269 #define XFS_BTCUR_BPRV_WASDEL   1                       /* was delayed */
 270                 } b;
 271         }               bc_private;     /* per-btree type data */
 272 } xfs_btree_cur_t;
 273
 274 /* cursor flags */
 275 #define XFS_BTREE_LONG_PTRS             (1<<0)  /* pointers are 64bits long */
 276 #define XFS_BTREE_ROOT_IN_INODE         (1<<1)  /* root may be variable size */
 277 #define XFS_BTREE_LASTREC_UPDATE        (1<<2)  /* track last rec externally */
 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 *)XFS_BUF_PTR(bp))
 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_dfsbno_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
 381 /*
 382  * Read-ahead the block, don't wait for it, don't return a buffer.
 383  * Long-form addressing.
 384  */
 385 void                                    /* error */
 386 xfs_btree_reada_bufl(
 387         struct xfs_mount        *mp,    /* file system mount point */
 388         xfs_fsblock_t           fsbno,  /* file system block number */
 389         xfs_extlen_t            count); /* count of filesystem blocks */
 390
 391 /*
 392  * Read-ahead the block, don't wait for it, don't return a buffer.
 393  * Short-form addressing.
 394  */
 395 void                                    /* error */
 396 xfs_btree_reada_bufs(
 397         struct xfs_mount        *mp,    /* file system mount point */
 398         xfs_agnumber_t          agno,   /* allocation group number */
 399         xfs_agblock_t           agbno,  /* allocation group block number */
 400         xfs_extlen_t            count); /* count of filesystem blocks */
 401
 402 /*
 403  * Set the buffer for level "lev" in the cursor to bp, releasing
 404  * any previous buffer.
 405  */
 406 void
 407 xfs_btree_setbuf(
 408         xfs_btree_cur_t         *cur,   /* btree cursor */
 409         int                     lev,    /* level in btree */
 410         struct xfs_buf          *bp);   /* new buffer to set */
 411
 412
 413 /*
 414  * Common btree core entry points.
 415  */
 416 int xfs_btree_increment(struct xfs_btree_cur *, int, int *);
 417 int xfs_btree_decrement(struct xfs_btree_cur *, int, int *);
 418 int xfs_btree_lookup(struct xfs_btree_cur *, xfs_lookup_t, int *);
 419 int xfs_btree_update(struct xfs_btree_cur *, union xfs_btree_rec *);
 420 int xfs_btree_new_iroot(struct xfs_btree_cur *, int *, int *);
 421 int xfs_btree_insert(struct xfs_btree_cur *, int *);
 422 int xfs_btree_delete(struct xfs_btree_cur *, int *);
 423 int xfs_btree_get_rec(struct xfs_btree_cur *, union xfs_btree_rec **, int *);
 424
 425 /*
 426  * Internal btree helpers also used by xfs_bmap.c.
 427  */
 428 void xfs_btree_log_block(struct xfs_btree_cur *, struct xfs_buf *, int);
 429 void xfs_btree_log_recs(struct xfs_btree_cur *, struct xfs_buf *, int, int);
 430
 431 /*
 432  * Helpers.
 433  */
 434 static inline int xfs_btree_get_numrecs(struct xfs_btree_block *block)
 435 {
 436         return be16_to_cpu(block->bb_numrecs);
 437 }
 438
 439 static inline void xfs_btree_set_numrecs(struct xfs_btree_block *block,
 440                 __uint16_t numrecs)
 441 {
 442         block->bb_numrecs = cpu_to_be16(numrecs);
 443 }
 444
 445 static inline int xfs_btree_get_level(struct xfs_btree_block *block)
 446 {
 447         return be16_to_cpu(block->bb_level);
 448 }
 449
 450
 451 /*
 452  * Min and max functions for extlen, agblock, fileoff, and filblks types.
 453  */
 454 #define XFS_EXTLEN_MIN(a,b)     min_t(xfs_extlen_t, (a), (b))
 455 #define XFS_EXTLEN_MAX(a,b)     max_t(xfs_extlen_t, (a), (b))
 456 #define XFS_AGBLOCK_MIN(a,b)    min_t(xfs_agblock_t, (a), (b))
 457 #define XFS_AGBLOCK_MAX(a,b)    max_t(xfs_agblock_t, (a), (b))
 458 #define XFS_FILEOFF_MIN(a,b)    min_t(xfs_fileoff_t, (a), (b))
 459 #define XFS_FILEOFF_MAX(a,b)    max_t(xfs_fileoff_t, (a), (b))
 460 #define XFS_FILBLKS_MIN(a,b)    min_t(xfs_filblks_t, (a), (b))
 461 #define XFS_FILBLKS_MAX(a,b)    max_t(xfs_filblks_t, (a), (b))
 462
 463 #define XFS_FSB_SANITY_CHECK(mp,fsb)    \
 464         (XFS_FSB_TO_AGNO(mp, fsb) < mp->m_sb.sb_agcount && \
 465                 XFS_FSB_TO_AGBNO(mp, fsb) < mp->m_sb.sb_agblocks)
 466
 467 #endif  /* __XFS_BTREE_H__ */