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  * Short form header: space allocation btrees.
  43  */
  44 typedef struct xfs_btree_sblock {
  45         __be32          bb_magic;       /* magic number for block type */
  46         __be16          bb_level;       /* 0 is a leaf */
  47         __be16          bb_numrecs;     /* current # of data records */
  48         __be32          bb_leftsib;     /* left sibling block or NULLAGBLOCK */
  49         __be32          bb_rightsib;    /* right sibling block or NULLAGBLOCK */
  50 } xfs_btree_sblock_t;
  51
  52 /*
  53  * Long form header: bmap btrees.
  54  */
  55 typedef struct xfs_btree_lblock {
  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         __be64          bb_leftsib;     /* left sibling block or NULLDFSBNO */
  60         __be64          bb_rightsib;    /* right sibling block or NULLDFSBNO */
  61 } xfs_btree_lblock_t;
  62
  63 /*
  64  * Combined header and structure, used by common code.
  65  */
  66 typedef struct xfs_btree_hdr
  67 {
  68         __be32          bb_magic;       /* magic number for block type */
  69         __be16          bb_level;       /* 0 is a leaf */
  70         __be16          bb_numrecs;     /* current # of data records */
  71 } xfs_btree_hdr_t;
  72
  73 typedef struct xfs_btree_block {
  74         xfs_btree_hdr_t bb_h;           /* header */
  75         union {
  76                 struct {
  77                         __be32          bb_leftsib;
  78                         __be32          bb_rightsib;
  79                 } s;                    /* short form pointers */
  80                 struct  {
  81                         __be64          bb_leftsib;
  82                         __be64          bb_rightsib;
  83                 } l;                    /* long form pointers */
  84         } bb_u;                         /* rest */
  85 } xfs_btree_block_t;
  86
  87 /*
  88  * For logging record fields.
  89  */
  90 #define XFS_BB_MAGIC            0x01
  91 #define XFS_BB_LEVEL            0x02
  92 #define XFS_BB_NUMRECS          0x04
  93 #define XFS_BB_LEFTSIB          0x08
  94 #define XFS_BB_RIGHTSIB         0x10
  95 #define XFS_BB_NUM_BITS         5
  96 #define XFS_BB_ALL_BITS         ((1 << XFS_BB_NUM_BITS) - 1)
  97
  98 /*
  99  * Boolean to select which form of xfs_btree_block_t.bb_u to use.
 100  */
 101 #define XFS_BTREE_LONG_PTRS(btnum)      ((btnum) == XFS_BTNUM_BMAP)
 102
 103 /*
 104  * Magic numbers for btree blocks.
 105  */
 106 extern const __uint32_t xfs_magics[];
 107
 108 /*
 109  * Maximum and minimum records in a btree block.
 110  * Given block size, type prefix, and leaf flag (0 or 1).
 111  * The divisor below is equivalent to lf ? (e1) : (e2) but that produces
 112  * compiler warnings.
 113  */
 114 #define XFS_BTREE_BLOCK_MAXRECS(bsz,t,lf)       \
 115         ((int)(((bsz) - (uint)sizeof(t ## _block_t)) / \
 116          (((lf) * (uint)sizeof(t ## _rec_t)) + \
 117           ((1 - (lf)) * \
 118            ((uint)sizeof(t ## _key_t) + (uint)sizeof(t ## _ptr_t))))))
 119 #define XFS_BTREE_BLOCK_MINRECS(bsz,t,lf)       \
 120         (XFS_BTREE_BLOCK_MAXRECS(bsz,t,lf) / 2)
 121
 122 /*
 123  * Record, key, and pointer address calculation macros.
 124  * Given block size, type prefix, block pointer, and index of requested entry
 125  * (first entry numbered 1).
 126  */
 127 #define XFS_BTREE_REC_ADDR(t,bb,i)      \
 128         ((t ## _rec_t *)((char *)(bb) + sizeof(t ## _block_t) + \
 129          ((i) - 1) * sizeof(t ## _rec_t)))
 130 #define XFS_BTREE_KEY_ADDR(t,bb,i)      \
 131         ((t ## _key_t *)((char *)(bb) + sizeof(t ## _block_t) + \
 132          ((i) - 1) * sizeof(t ## _key_t)))
 133 #define XFS_BTREE_PTR_ADDR(t,bb,i,mxr)  \
 134         ((t ## _ptr_t *)((char *)(bb) + sizeof(t ## _block_t) + \
 135          (mxr) * sizeof(t ## _key_t) + ((i) - 1) * sizeof(t ## _ptr_t)))
 136
 137 #define XFS_BTREE_MAXLEVELS     8       /* max of all btrees */
 138
 139 /*
 140  * Btree cursor structure.
 141  * This collects all information needed by the btree code in one place.
 142  */
 143 typedef struct xfs_btree_cur
 144 {
 145         struct xfs_trans        *bc_tp; /* transaction we're in, if any */
 146         struct xfs_mount        *bc_mp; /* file system mount struct */
 147         union {
 148                 xfs_alloc_rec_incore_t  a;
 149                 xfs_bmbt_irec_t         b;
 150                 xfs_inobt_rec_incore_t  i;
 151         }               bc_rec;         /* current insert/search record value */
 152         struct xfs_buf  *bc_bufs[XFS_BTREE_MAXLEVELS];  /* buf ptr per level */
 153         int             bc_ptrs[XFS_BTREE_MAXLEVELS];   /* key/record # */
 154         __uint8_t       bc_ra[XFS_BTREE_MAXLEVELS];     /* readahead bits */
 155 #define XFS_BTCUR_LEFTRA        1       /* left sibling has been read-ahead */
 156 #define XFS_BTCUR_RIGHTRA       2       /* right sibling has been read-ahead */
 157         __uint8_t       bc_nlevels;     /* number of levels in the tree */
 158         __uint8_t       bc_blocklog;    /* log2(blocksize) of btree blocks */
 159         xfs_btnum_t     bc_btnum;       /* identifies which btree type */
 160         union {
 161                 struct {                        /* needed for BNO, CNT, INO */
 162                         struct xfs_buf  *agbp;  /* agf/agi buffer pointer */
 163                         xfs_agnumber_t  agno;   /* ag number */
 164                 } a;
 165                 struct {                        /* needed for BMAP */
 166                         struct xfs_inode *ip;   /* pointer to our inode */
 167                         struct xfs_bmap_free *flist;    /* list to free after */
 168                         xfs_fsblock_t   firstblock;     /* 1st blk allocated */
 169                         int             allocated;      /* count of alloced */
 170                         short           forksize;       /* fork's inode space */
 171                         char            whichfork;      /* data or attr fork */
 172                         char            flags;          /* flags */
 173 #define XFS_BTCUR_BPRV_WASDEL   1                       /* was delayed */
 174                 } b;
 175         }               bc_private;     /* per-btree type data */
 176 } xfs_btree_cur_t;
 177
 178 #define XFS_BTREE_NOERROR       0
 179 #define XFS_BTREE_ERROR         1
 180
 181 /*
 182  * Convert from buffer to btree block header.
 183  */
 184 #define XFS_BUF_TO_BLOCK(bp)    ((xfs_btree_block_t *)XFS_BUF_PTR(bp))
 185 #define XFS_BUF_TO_LBLOCK(bp)   ((xfs_btree_lblock_t *)XFS_BUF_PTR(bp))
 186 #define XFS_BUF_TO_SBLOCK(bp)   ((xfs_btree_sblock_t *)XFS_BUF_PTR(bp))
 187
 188
 189 #ifdef __KERNEL__
 190
 191 #ifdef DEBUG
 192 /*
 193  * Debug routine: check that block header is ok.
 194  */
 195 void
 196 xfs_btree_check_block(
 197         xfs_btree_cur_t         *cur,   /* btree cursor */
 198         xfs_btree_block_t       *block, /* generic btree block pointer */
 199         int                     level,  /* level of the btree block */
 200         struct xfs_buf          *bp);   /* buffer containing block, if any */
 201
 202 /*
 203  * Debug routine: check that keys are in the right order.
 204  */
 205 void
 206 xfs_btree_check_key(
 207         xfs_btnum_t             btnum,  /* btree identifier */
 208         void                    *ak1,   /* pointer to left (lower) key */
 209         void                    *ak2);  /* pointer to right (higher) key */
 210
 211 /*
 212  * Debug routine: check that records are in the right order.
 213  */
 214 void
 215 xfs_btree_check_rec(
 216         xfs_btnum_t             btnum,  /* btree identifier */
 217         void                    *ar1,   /* pointer to left (lower) record */
 218         void                    *ar2);  /* pointer to right (higher) record */
 219 #else
 220 #define xfs_btree_check_block(a,b,c,d)
 221 #define xfs_btree_check_key(a,b,c)
 222 #define xfs_btree_check_rec(a,b,c)
 223 #endif  /* DEBUG */
 224
 225 /*
 226  * Checking routine: check that long form block header is ok.
 227  */
 228 int                                     /* error (0 or EFSCORRUPTED) */
 229 xfs_btree_check_lblock(
 230         xfs_btree_cur_t         *cur,   /* btree cursor */
 231         xfs_btree_lblock_t      *block, /* btree long form block pointer */
 232         int                     level,  /* level of the btree block */
 233         struct xfs_buf          *bp);   /* buffer containing block, if any */
 234
 235 /*
 236  * Checking routine: check that (long) pointer is ok.
 237  */
 238 int                                     /* error (0 or EFSCORRUPTED) */
 239 xfs_btree_check_lptr(
 240         xfs_btree_cur_t         *cur,   /* btree cursor */
 241         xfs_dfsbno_t            ptr,    /* btree block disk address */
 242         int                     level); /* btree block level */
 243
 244 #define xfs_btree_check_lptr_disk(cur, ptr, level) \
 245         xfs_btree_check_lptr(cur, be64_to_cpu(ptr), level)
 246
 247 /*
 248  * Checking routine: check that short form block header is ok.
 249  */
 250 int                                     /* error (0 or EFSCORRUPTED) */
 251 xfs_btree_check_sblock(
 252         xfs_btree_cur_t         *cur,   /* btree cursor */
 253         xfs_btree_sblock_t      *block, /* btree short form block pointer */
 254         int                     level,  /* level of the btree block */
 255         struct xfs_buf          *bp);   /* buffer containing block */
 256
 257 /*
 258  * Checking routine: check that (short) pointer is ok.
 259  */
 260 int                                     /* error (0 or EFSCORRUPTED) */
 261 xfs_btree_check_sptr(
 262         xfs_btree_cur_t         *cur,   /* btree cursor */
 263         xfs_agblock_t           ptr,    /* btree block disk address */
 264         int                     level); /* btree block level */
 265
 266 /*
 267  * Delete the btree cursor.
 268  */
 269 void
 270 xfs_btree_del_cursor(
 271         xfs_btree_cur_t         *cur,   /* btree cursor */
 272         int                     error); /* del because of error */
 273
 274 /*
 275  * Duplicate the btree cursor.
 276  * Allocate a new one, copy the record, re-get the buffers.
 277  */
 278 int                                     /* error */
 279 xfs_btree_dup_cursor(
 280         xfs_btree_cur_t         *cur,   /* input cursor */
 281         xfs_btree_cur_t         **ncur);/* output cursor */
 282
 283 /*
 284  * Change the cursor to point to the first record in the current block
 285  * at the given level.  Other levels are unaffected.
 286  */
 287 int                                     /* success=1, failure=0 */
 288 xfs_btree_firstrec(
 289         xfs_btree_cur_t         *cur,   /* btree cursor */
 290         int                     level); /* level to change */
 291
 292 /*
 293  * Get a buffer for the block, return it with no data read.
 294  * Long-form addressing.
 295  */
 296 struct xfs_buf *                                /* buffer for fsbno */
 297 xfs_btree_get_bufl(
 298         struct xfs_mount        *mp,    /* file system mount point */
 299         struct xfs_trans        *tp,    /* transaction pointer */
 300         xfs_fsblock_t           fsbno,  /* file system block number */
 301         uint                    lock);  /* lock flags for get_buf */
 302
 303 /*
 304  * Get a buffer for the block, return it with no data read.
 305  * Short-form addressing.
 306  */
 307 struct xfs_buf *                                /* buffer for agno/agbno */
 308 xfs_btree_get_bufs(
 309         struct xfs_mount        *mp,    /* file system mount point */
 310         struct xfs_trans        *tp,    /* transaction pointer */
 311         xfs_agnumber_t          agno,   /* allocation group number */
 312         xfs_agblock_t           agbno,  /* allocation group block number */
 313         uint                    lock);  /* lock flags for get_buf */
 314
 315 /*
 316  * Allocate a new btree cursor.
 317  * The cursor is either for allocation (A) or bmap (B).
 318  */
 319 xfs_btree_cur_t *                       /* new btree cursor */
 320 xfs_btree_init_cursor(
 321         struct xfs_mount        *mp,    /* file system mount point */
 322         struct xfs_trans        *tp,    /* transaction pointer */
 323         struct xfs_buf          *agbp,  /* (A only) buffer for agf structure */
 324         xfs_agnumber_t          agno,   /* (A only) allocation group number */
 325         xfs_btnum_t             btnum,  /* btree identifier */
 326         struct xfs_inode        *ip,    /* (B only) inode owning the btree */
 327         int                     whichfork); /* (B only) data/attr fork */
 328
 329 /*
 330  * Check for the cursor referring to the last block at the given level.
 331  */
 332 int                                     /* 1=is last block, 0=not last block */
 333 xfs_btree_islastblock(
 334         xfs_btree_cur_t         *cur,   /* btree cursor */
 335         int                     level); /* level to check */
 336
 337 /*
 338  * Change the cursor to point to the last record in the current block
 339  * at the given level.  Other levels are unaffected.
 340  */
 341 int                                     /* success=1, failure=0 */
 342 xfs_btree_lastrec(
 343         xfs_btree_cur_t         *cur,   /* btree cursor */
 344         int                     level); /* level to change */
 345
 346 /*
 347  * Compute first and last byte offsets for the fields given.
 348  * Interprets the offsets table, which contains struct field offsets.
 349  */
 350 void
 351 xfs_btree_offsets(
 352         __int64_t               fields, /* bitmask of fields */
 353         const short             *offsets,/* table of field offsets */
 354         int                     nbits,  /* number of bits to inspect */
 355         int                     *first, /* output: first byte offset */
 356         int                     *last); /* output: last byte offset */
 357
 358 /*
 359  * Get a buffer for the block, return it read in.
 360  * Long-form addressing.
 361  */
 362 int                                     /* error */
 363 xfs_btree_read_bufl(
 364         struct xfs_mount        *mp,    /* file system mount point */
 365         struct xfs_trans        *tp,    /* transaction pointer */
 366         xfs_fsblock_t           fsbno,  /* file system block number */
 367         uint                    lock,   /* lock flags for read_buf */
 368         struct xfs_buf          **bpp,  /* buffer for fsbno */
 369         int                     refval);/* ref count value for buffer */
 370
 371 /*
 372  * Get a buffer for the block, return it read in.
 373  * Short-form addressing.
 374  */
 375 int                                     /* error */
 376 xfs_btree_read_bufs(
 377         struct xfs_mount        *mp,    /* file system mount point */
 378         struct xfs_trans        *tp,    /* transaction pointer */
 379         xfs_agnumber_t          agno,   /* allocation group number */
 380         xfs_agblock_t           agbno,  /* allocation group block number */
 381         uint                    lock,   /* lock flags for read_buf */
 382         struct xfs_buf          **bpp,  /* buffer for agno/agbno */
 383         int                     refval);/* ref count value for buffer */
 384
 385 /*
 386  * Read-ahead the block, don't wait for it, don't return a buffer.
 387  * Long-form addressing.
 388  */
 389 void                                    /* error */
 390 xfs_btree_reada_bufl(
 391         struct xfs_mount        *mp,    /* file system mount point */
 392         xfs_fsblock_t           fsbno,  /* file system block number */
 393         xfs_extlen_t            count); /* count of filesystem blocks */
 394
 395 /*
 396  * Read-ahead the block, don't wait for it, don't return a buffer.
 397  * Short-form addressing.
 398  */
 399 void                                    /* error */
 400 xfs_btree_reada_bufs(
 401         struct xfs_mount        *mp,    /* file system mount point */
 402         xfs_agnumber_t          agno,   /* allocation group number */
 403         xfs_agblock_t           agbno,  /* allocation group block number */
 404         xfs_extlen_t            count); /* count of filesystem blocks */
 405
 406 /*
 407  * Read-ahead btree blocks, at the given level.
 408  * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
 409  */
 410 int                                     /* readahead block count */
 411 xfs_btree_readahead_core(
 412         xfs_btree_cur_t         *cur,   /* btree cursor */
 413         int                     lev,    /* level in btree */
 414         int                     lr);    /* left/right bits */
 415
 416 static inline int                       /* readahead block count */
 417 xfs_btree_readahead(
 418         xfs_btree_cur_t         *cur,   /* btree cursor */
 419         int                     lev,    /* level in btree */
 420         int                     lr)     /* left/right bits */
 421 {
 422         if ((cur->bc_ra[lev] | lr) == cur->bc_ra[lev])
 423                 return 0;
 424
 425         return xfs_btree_readahead_core(cur, lev, lr);
 426 }
 427
 428
 429 /*
 430  * Set the buffer for level "lev" in the cursor to bp, releasing
 431  * any previous buffer.
 432  */
 433 void
 434 xfs_btree_setbuf(
 435         xfs_btree_cur_t         *cur,   /* btree cursor */
 436         int                     lev,    /* level in btree */
 437         struct xfs_buf          *bp);   /* new buffer to set */
 438
 439 #endif  /* __KERNEL__ */
 440
 441
 442 /*
 443  * Min and max functions for extlen, agblock, fileoff, and filblks types.
 444  */
 445 #define XFS_EXTLEN_MIN(a,b)     min_t(xfs_extlen_t, (a), (b))
 446 #define XFS_EXTLEN_MAX(a,b)     max_t(xfs_extlen_t, (a), (b))
 447 #define XFS_AGBLOCK_MIN(a,b)    min_t(xfs_agblock_t, (a), (b))
 448 #define XFS_AGBLOCK_MAX(a,b)    max_t(xfs_agblock_t, (a), (b))
 449 #define XFS_FILEOFF_MIN(a,b)    min_t(xfs_fileoff_t, (a), (b))
 450 #define XFS_FILEOFF_MAX(a,b)    max_t(xfs_fileoff_t, (a), (b))
 451 #define XFS_FILBLKS_MIN(a,b)    min_t(xfs_filblks_t, (a), (b))
 452 #define XFS_FILBLKS_MAX(a,b)    max_t(xfs_filblks_t, (a), (b))
 453
 454 #define XFS_FSB_SANITY_CHECK(mp,fsb)    \
 455         (XFS_FSB_TO_AGNO(mp, fsb) < mp->m_sb.sb_agcount && \
 456                 XFS_FSB_TO_AGBNO(mp, fsb) < mp->m_sb.sb_agblocks)
 457
 458 #endif  /* __XFS_BTREE_H__ */