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 /*
  28  * This nonsense is to make -wlint happy.
  29  */
  30 #define XFS_LOOKUP_EQ   ((xfs_lookup_t)XFS_LOOKUP_EQi)
  31 #define XFS_LOOKUP_LE   ((xfs_lookup_t)XFS_LOOKUP_LEi)
  32 #define XFS_LOOKUP_GE   ((xfs_lookup_t)XFS_LOOKUP_GEi)
  33
  34 #define XFS_BTNUM_BNO   ((xfs_btnum_t)XFS_BTNUM_BNOi)
  35 #define XFS_BTNUM_CNT   ((xfs_btnum_t)XFS_BTNUM_CNTi)
  36 #define XFS_BTNUM_BMAP  ((xfs_btnum_t)XFS_BTNUM_BMAPi)
  37 #define XFS_BTNUM_INO   ((xfs_btnum_t)XFS_BTNUM_INOi)
  38
  39 /*
  40  * Short form header: space allocation btrees.
  41  */
  42 typedef struct xfs_btree_sblock {
  43         __be32          bb_magic;       /* magic number for block type */
  44         __be16          bb_level;       /* 0 is a leaf */
  45         __be16          bb_numrecs;     /* current # of data records */
  46         __be32          bb_leftsib;     /* left sibling block or NULLAGBLOCK */
  47         __be32          bb_rightsib;    /* right sibling block or NULLAGBLOCK */
  48 } xfs_btree_sblock_t;
  49
  50 /*
  51  * Long form header: bmap btrees.
  52  */
  53 typedef struct xfs_btree_lblock {
  54         __be32          bb_magic;       /* magic number for block type */
  55         __be16          bb_level;       /* 0 is a leaf */
  56         __be16          bb_numrecs;     /* current # of data records */
  57         __be64          bb_leftsib;     /* left sibling block or NULLDFSBNO */
  58         __be64          bb_rightsib;    /* right sibling block or NULLDFSBNO */
  59 } xfs_btree_lblock_t;
  60
  61 /*
  62  * Combined header and structure, used by common code.
  63  */
  64 typedef struct xfs_btree_hdr
  65 {
  66         __be32          bb_magic;       /* magic number for block type */
  67         __be16          bb_level;       /* 0 is a leaf */
  68         __be16          bb_numrecs;     /* current # of data records */
  69 } xfs_btree_hdr_t;
  70
  71 typedef struct xfs_btree_block {
  72         xfs_btree_hdr_t bb_h;           /* header */
  73         union {
  74                 struct {
  75                         __be32          bb_leftsib;
  76                         __be32          bb_rightsib;
  77                 } s;                    /* short form pointers */
  78                 struct  {
  79                         __be64          bb_leftsib;
  80                         __be64          bb_rightsib;
  81                 } l;                    /* long form pointers */
  82         } bb_u;                         /* rest */
  83 } xfs_btree_block_t;
  84
  85 /*
  86  * For logging record fields.
  87  */
  88 #define XFS_BB_MAGIC            0x01
  89 #define XFS_BB_LEVEL            0x02
  90 #define XFS_BB_NUMRECS          0x04
  91 #define XFS_BB_LEFTSIB          0x08
  92 #define XFS_BB_RIGHTSIB         0x10
  93 #define XFS_BB_NUM_BITS         5
  94 #define XFS_BB_ALL_BITS         ((1 << XFS_BB_NUM_BITS) - 1)
  95
  96 /*
  97  * Boolean to select which form of xfs_btree_block_t.bb_u to use.
  98  */
  99 #define XFS_BTREE_LONG_PTRS(btnum)      ((btnum) == XFS_BTNUM_BMAP)
 100
 101 /*
 102  * Magic numbers for btree blocks.
 103  */
 104 extern const __uint32_t xfs_magics[];
 105
 106 /*
 107  * Maximum and minimum records in a btree block.
 108  * Given block size, type prefix, and leaf flag (0 or 1).
 109  * The divisor below is equivalent to lf ? (e1) : (e2) but that produces
 110  * compiler warnings.
 111  */
 112 #define XFS_BTREE_BLOCK_MAXRECS(bsz,t,lf)       \
 113         ((int)(((bsz) - (uint)sizeof(t ## _block_t)) / \
 114          (((lf) * (uint)sizeof(t ## _rec_t)) + \
 115           ((1 - (lf)) * \
 116            ((uint)sizeof(t ## _key_t) + (uint)sizeof(t ## _ptr_t))))))
 117 #define XFS_BTREE_BLOCK_MINRECS(bsz,t,lf)       \
 118         (XFS_BTREE_BLOCK_MAXRECS(bsz,t,lf) / 2)
 119
 120 /*
 121  * Record, key, and pointer address calculation macros.
 122  * Given block size, type prefix, block pointer, and index of requested entry
 123  * (first entry numbered 1).
 124  */
 125 #define XFS_BTREE_REC_ADDR(bsz,t,bb,i,mxr)      \
 126         ((t ## _rec_t *)((char *)(bb) + sizeof(t ## _block_t) + \
 127          ((i) - 1) * sizeof(t ## _rec_t)))
 128 #define XFS_BTREE_KEY_ADDR(bsz,t,bb,i,mxr)      \
 129         ((t ## _key_t *)((char *)(bb) + sizeof(t ## _block_t) + \
 130          ((i) - 1) * sizeof(t ## _key_t)))
 131 #define XFS_BTREE_PTR_ADDR(bsz,t,bb,i,mxr)      \
 132         ((t ## _ptr_t *)((char *)(bb) + sizeof(t ## _block_t) + \
 133          (mxr) * sizeof(t ## _key_t) + ((i) - 1) * sizeof(t ## _ptr_t)))
 134
 135 #define XFS_BTREE_MAXLEVELS     8       /* max of all btrees */
 136
 137 /*
 138  * Btree cursor structure.
 139  * This collects all information needed by the btree code in one place.
 140  */
 141 typedef struct xfs_btree_cur
 142 {
 143         struct xfs_trans        *bc_tp; /* transaction we're in, if any */
 144         struct xfs_mount        *bc_mp; /* file system mount struct */
 145         union {
 146                 xfs_alloc_rec_incore_t  a;
 147                 xfs_bmbt_irec_t         b;
 148                 xfs_inobt_rec_t         i;
 149         }               bc_rec;         /* current insert/search record value */
 150         struct xfs_buf  *bc_bufs[XFS_BTREE_MAXLEVELS];  /* buf ptr per level */
 151         int             bc_ptrs[XFS_BTREE_MAXLEVELS];   /* key/record # */
 152         __uint8_t       bc_ra[XFS_BTREE_MAXLEVELS];     /* readahead bits */
 153 #define XFS_BTCUR_LEFTRA        1       /* left sibling has been read-ahead */
 154 #define XFS_BTCUR_RIGHTRA       2       /* right sibling has been read-ahead */
 155         __uint8_t       bc_nlevels;     /* number of levels in the tree */
 156         __uint8_t       bc_blocklog;    /* log2(blocksize) of btree blocks */
 157         xfs_btnum_t     bc_btnum;       /* identifies which btree type */
 158         union {
 159                 struct {                        /* needed for BNO, CNT */
 160                         struct xfs_buf  *agbp;  /* agf buffer pointer */
 161                         xfs_agnumber_t  agno;   /* ag number */
 162                 } a;
 163                 struct {                        /* needed for BMAP */
 164                         struct xfs_inode *ip;   /* pointer to our inode */
 165                         struct xfs_bmap_free *flist;    /* list to free after */
 166                         xfs_fsblock_t   firstblock;     /* 1st blk allocated */
 167                         int             allocated;      /* count of alloced */
 168                         short           forksize;       /* fork's inode space */
 169                         char            whichfork;      /* data or attr fork */
 170                         char            flags;          /* flags */
 171 #define XFS_BTCUR_BPRV_WASDEL   1                       /* was delayed */
 172                 } b;
 173                 struct {                        /* needed for INO */
 174                         struct xfs_buf  *agbp;  /* agi buffer pointer */
 175                         xfs_agnumber_t  agno;   /* ag number */
 176                 } i;
 177         }               bc_private;     /* per-btree type data */
 178 } xfs_btree_cur_t;
 179
 180 #define XFS_BTREE_NOERROR       0
 181 #define XFS_BTREE_ERROR         1
 182
 183 /*
 184  * Convert from buffer to btree block header.
 185  */
 186 #define XFS_BUF_TO_BLOCK(bp)    ((xfs_btree_block_t *)XFS_BUF_PTR(bp))
 187 #define XFS_BUF_TO_LBLOCK(bp)   ((xfs_btree_lblock_t *)XFS_BUF_PTR(bp))
 188 #define XFS_BUF_TO_SBLOCK(bp)   ((xfs_btree_sblock_t *)XFS_BUF_PTR(bp))
 189
 190
 191 #ifdef __KERNEL__
 192
 193 #ifdef DEBUG
 194 /*
 195  * Debug routine: check that block header is ok.
 196  */
 197 void
 198 xfs_btree_check_block(
 199         xfs_btree_cur_t         *cur,   /* btree cursor */
 200         xfs_btree_block_t       *block, /* generic btree block pointer */
 201         int                     level,  /* level of the btree block */
 202         struct xfs_buf          *bp);   /* buffer containing block, if any */
 203
 204 /*
 205  * Debug routine: check that keys are in the right order.
 206  */
 207 void
 208 xfs_btree_check_key(
 209         xfs_btnum_t             btnum,  /* btree identifier */
 210         void                    *ak1,   /* pointer to left (lower) key */
 211         void                    *ak2);  /* pointer to right (higher) key */
 212
 213 /*
 214  * Debug routine: check that records are in the right order.
 215  */
 216 void
 217 xfs_btree_check_rec(
 218         xfs_btnum_t             btnum,  /* btree identifier */
 219         void                    *ar1,   /* pointer to left (lower) record */
 220         void                    *ar2);  /* pointer to right (higher) record */
 221 #else
 222 #define xfs_btree_check_block(a,b,c,d)
 223 #define xfs_btree_check_key(a,b,c)
 224 #define xfs_btree_check_rec(a,b,c)
 225 #endif  /* DEBUG */
 226
 227 /*
 228  * Checking routine: check that long form block header is ok.
 229  */
 230 int                                     /* error (0 or EFSCORRUPTED) */
 231 xfs_btree_check_lblock(
 232         xfs_btree_cur_t         *cur,   /* btree cursor */
 233         xfs_btree_lblock_t      *block, /* btree long form block pointer */
 234         int                     level,  /* level of the btree block */
 235         struct xfs_buf          *bp);   /* buffer containing block, if any */
 236
 237 /*
 238  * Checking routine: check that (long) pointer is ok.
 239  */
 240 int                                     /* error (0 or EFSCORRUPTED) */
 241 xfs_btree_check_lptr(
 242         xfs_btree_cur_t         *cur,   /* btree cursor */
 243         xfs_dfsbno_t            ptr,    /* btree block disk address */
 244         int                     level); /* btree block level */
 245
 246 /*
 247  * Checking routine: check that short form block header is ok.
 248  */
 249 int                                     /* error (0 or EFSCORRUPTED) */
 250 xfs_btree_check_sblock(
 251         xfs_btree_cur_t         *cur,   /* btree cursor */
 252         xfs_btree_sblock_t      *block, /* btree short form block pointer */
 253         int                     level,  /* level of the btree block */
 254         struct xfs_buf          *bp);   /* buffer containing block */
 255
 256 /*
 257  * Checking routine: check that (short) pointer is ok.
 258  */
 259 int                                     /* error (0 or EFSCORRUPTED) */
 260 xfs_btree_check_sptr(
 261         xfs_btree_cur_t         *cur,   /* btree cursor */
 262         xfs_agblock_t           ptr,    /* btree block disk address */
 263         int                     level); /* btree block level */
 264
 265 /*
 266  * Delete the btree cursor.
 267  */
 268 void
 269 xfs_btree_del_cursor(
 270         xfs_btree_cur_t         *cur,   /* btree cursor */
 271         int                     error); /* del because of error */
 272
 273 /*
 274  * Duplicate the btree cursor.
 275  * Allocate a new one, copy the record, re-get the buffers.
 276  */
 277 int                                     /* error */
 278 xfs_btree_dup_cursor(
 279         xfs_btree_cur_t         *cur,   /* input cursor */
 280         xfs_btree_cur_t         **ncur);/* output cursor */
 281
 282 /*
 283  * Change the cursor to point to the first record in the current block
 284  * at the given level.  Other levels are unaffected.
 285  */
 286 int                                     /* success=1, failure=0 */
 287 xfs_btree_firstrec(
 288         xfs_btree_cur_t         *cur,   /* btree cursor */
 289         int                     level); /* level to change */
 290
 291 /*
 292  * Get a buffer for the block, return it with no data read.
 293  * Long-form addressing.
 294  */
 295 struct xfs_buf *                                /* buffer for fsbno */
 296 xfs_btree_get_bufl(
 297         struct xfs_mount        *mp,    /* file system mount point */
 298         struct xfs_trans        *tp,    /* transaction pointer */
 299         xfs_fsblock_t           fsbno,  /* file system block number */
 300         uint                    lock);  /* lock flags for get_buf */
 301
 302 /*
 303  * Get a buffer for the block, return it with no data read.
 304  * Short-form addressing.
 305  */
 306 struct xfs_buf *                                /* buffer for agno/agbno */
 307 xfs_btree_get_bufs(
 308         struct xfs_mount        *mp,    /* file system mount point */
 309         struct xfs_trans        *tp,    /* transaction pointer */
 310         xfs_agnumber_t          agno,   /* allocation group number */
 311         xfs_agblock_t           agbno,  /* allocation group block number */
 312         uint                    lock);  /* lock flags for get_buf */
 313
 314 /*
 315  * Allocate a new btree cursor.
 316  * The cursor is either for allocation (A) or bmap (B).
 317  */
 318 xfs_btree_cur_t *                       /* new btree cursor */
 319 xfs_btree_init_cursor(
 320         struct xfs_mount        *mp,    /* file system mount point */
 321         struct xfs_trans        *tp,    /* transaction pointer */
 322         struct xfs_buf          *agbp,  /* (A only) buffer for agf structure */
 323         xfs_agnumber_t          agno,   /* (A only) allocation group number */
 324         xfs_btnum_t             btnum,  /* btree identifier */
 325         struct xfs_inode        *ip,    /* (B only) inode owning the btree */
 326         int                     whichfork); /* (B only) data/attr fork */
 327
 328 /*
 329  * Check for the cursor referring to the last block at the given level.
 330  */
 331 int                                     /* 1=is last block, 0=not last block */
 332 xfs_btree_islastblock(
 333         xfs_btree_cur_t         *cur,   /* btree cursor */
 334         int                     level); /* level to check */
 335
 336 /*
 337  * Change the cursor to point to the last record in the current block
 338  * at the given level.  Other levels are unaffected.
 339  */
 340 int                                     /* success=1, failure=0 */
 341 xfs_btree_lastrec(
 342         xfs_btree_cur_t         *cur,   /* btree cursor */
 343         int                     level); /* level to change */
 344
 345 /*
 346  * Compute first and last byte offsets for the fields given.
 347  * Interprets the offsets table, which contains struct field offsets.
 348  */
 349 void
 350 xfs_btree_offsets(
 351         __int64_t               fields, /* bitmask of fields */
 352         const short             *offsets,/* table of field offsets */
 353         int                     nbits,  /* number of bits to inspect */
 354         int                     *first, /* output: first byte offset */
 355         int                     *last); /* output: last byte offset */
 356
 357 /*
 358  * Get a buffer for the block, return it read in.
 359  * Long-form addressing.
 360  */
 361 int                                     /* error */
 362 xfs_btree_read_bufl(
 363         struct xfs_mount        *mp,    /* file system mount point */
 364         struct xfs_trans        *tp,    /* transaction pointer */
 365         xfs_fsblock_t           fsbno,  /* file system block number */
 366         uint                    lock,   /* lock flags for read_buf */
 367         struct xfs_buf          **bpp,  /* buffer for fsbno */
 368         int                     refval);/* ref count value for buffer */
 369
 370 /*
 371  * Get a buffer for the block, return it read in.
 372  * Short-form addressing.
 373  */
 374 int                                     /* error */
 375 xfs_btree_read_bufs(
 376         struct xfs_mount        *mp,    /* file system mount point */
 377         struct xfs_trans        *tp,    /* transaction pointer */
 378         xfs_agnumber_t          agno,   /* allocation group number */
 379         xfs_agblock_t           agbno,  /* allocation group block number */
 380         uint                    lock,   /* lock flags for read_buf */
 381         struct xfs_buf          **bpp,  /* buffer for agno/agbno */
 382         int                     refval);/* ref count value for buffer */
 383
 384 /*
 385  * Read-ahead the block, don't wait for it, don't return a buffer.
 386  * Long-form addressing.
 387  */
 388 void                                    /* error */
 389 xfs_btree_reada_bufl(
 390         struct xfs_mount        *mp,    /* file system mount point */
 391         xfs_fsblock_t           fsbno,  /* file system block number */
 392         xfs_extlen_t            count); /* count of filesystem blocks */
 393
 394 /*
 395  * Read-ahead the block, don't wait for it, don't return a buffer.
 396  * Short-form addressing.
 397  */
 398 void                                    /* error */
 399 xfs_btree_reada_bufs(
 400         struct xfs_mount        *mp,    /* file system mount point */
 401         xfs_agnumber_t          agno,   /* allocation group number */
 402         xfs_agblock_t           agbno,  /* allocation group block number */
 403         xfs_extlen_t            count); /* count of filesystem blocks */
 404
 405 /*
 406  * Read-ahead btree blocks, at the given level.
 407  * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
 408  */
 409 int                                     /* readahead block count */
 410 xfs_btree_readahead_core(
 411         xfs_btree_cur_t         *cur,   /* btree cursor */
 412         int                     lev,    /* level in btree */
 413         int                     lr);    /* left/right bits */
 414
 415 static inline int                       /* readahead block count */
 416 xfs_btree_readahead(
 417         xfs_btree_cur_t         *cur,   /* btree cursor */
 418         int                     lev,    /* level in btree */
 419         int                     lr)     /* left/right bits */
 420 {
 421         if ((cur->bc_ra[lev] | lr) == cur->bc_ra[lev])
 422                 return 0;
 423
 424         return xfs_btree_readahead_core(cur, lev, lr);
 425 }
 426
 427
 428 /*
 429  * Set the buffer for level "lev" in the cursor to bp, releasing
 430  * any previous buffer.
 431  */
 432 void
 433 xfs_btree_setbuf(
 434         xfs_btree_cur_t         *cur,   /* btree cursor */
 435         int                     lev,    /* level in btree */
 436         struct xfs_buf          *bp);   /* new buffer to set */
 437
 438 #endif  /* __KERNEL__ */
 439
 440
 441 /*
 442  * Min and max functions for extlen, agblock, fileoff, and filblks types.
 443  */
 444 #define XFS_EXTLEN_MIN(a,b)     \
 445         ((xfs_extlen_t)(a) < (xfs_extlen_t)(b) ? \
 446                 (xfs_extlen_t)(a) : (xfs_extlen_t)(b))
 447 #define XFS_EXTLEN_MAX(a,b)     \
 448         ((xfs_extlen_t)(a) > (xfs_extlen_t)(b) ? \
 449                 (xfs_extlen_t)(a) : (xfs_extlen_t)(b))
 450 #define XFS_AGBLOCK_MIN(a,b)    \
 451         ((xfs_agblock_t)(a) < (xfs_agblock_t)(b) ? \
 452                 (xfs_agblock_t)(a) : (xfs_agblock_t)(b))
 453 #define XFS_AGBLOCK_MAX(a,b)    \
 454         ((xfs_agblock_t)(a) > (xfs_agblock_t)(b) ? \
 455                 (xfs_agblock_t)(a) : (xfs_agblock_t)(b))
 456 #define XFS_FILEOFF_MIN(a,b)    \
 457         ((xfs_fileoff_t)(a) < (xfs_fileoff_t)(b) ? \
 458                 (xfs_fileoff_t)(a) : (xfs_fileoff_t)(b))
 459 #define XFS_FILEOFF_MAX(a,b)    \
 460         ((xfs_fileoff_t)(a) > (xfs_fileoff_t)(b) ? \
 461                 (xfs_fileoff_t)(a) : (xfs_fileoff_t)(b))
 462 #define XFS_FILBLKS_MIN(a,b)    \
 463         ((xfs_filblks_t)(a) < (xfs_filblks_t)(b) ? \
 464                 (xfs_filblks_t)(a) : (xfs_filblks_t)(b))
 465 #define XFS_FILBLKS_MAX(a,b)    \
 466         ((xfs_filblks_t)(a) > (xfs_filblks_t)(b) ? \
 467                 (xfs_filblks_t)(a) : (xfs_filblks_t)(b))
 468
 469 #define XFS_FSB_SANITY_CHECK(mp,fsb)    \
 470         (XFS_FSB_TO_AGNO(mp, fsb) < mp->m_sb.sb_agcount && \
 471                 XFS_FSB_TO_AGBNO(mp, fsb) < mp->m_sb.sb_agblocks)
 472
 473 #endif  /* __XFS_BTREE_H__ */