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(t,bb,i)      \
 126         ((t ## _rec_t *)((char *)(bb) + sizeof(t ## _block_t) + \
 127          ((i) - 1) * sizeof(t ## _rec_t)))
 128 #define XFS_BTREE_KEY_ADDR(t,bb,i)      \
 129         ((t ## _key_t *)((char *)(bb) + sizeof(t ## _block_t) + \
 130          ((i) - 1) * sizeof(t ## _key_t)))
 131 #define XFS_BTREE_PTR_ADDR(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_incore_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 #define xfs_btree_check_lptr_disk(cur, ptr, level) \
 247         xfs_btree_check_lptr(cur, be64_to_cpu(ptr), level)
 248
 249 /*
 250  * Checking routine: check that short form block header is ok.
 251  */
 252 int                                     /* error (0 or EFSCORRUPTED) */
 253 xfs_btree_check_sblock(
 254         xfs_btree_cur_t         *cur,   /* btree cursor */
 255         xfs_btree_sblock_t      *block, /* btree short form block pointer */
 256         int                     level,  /* level of the btree block */
 257         struct xfs_buf          *bp);   /* buffer containing block */
 258
 259 /*
 260  * Checking routine: check that (short) pointer is ok.
 261  */
 262 int                                     /* error (0 or EFSCORRUPTED) */
 263 xfs_btree_check_sptr(
 264         xfs_btree_cur_t         *cur,   /* btree cursor */
 265         xfs_agblock_t           ptr,    /* btree block disk address */
 266         int                     level); /* btree block level */
 267
 268 /*
 269  * Delete the btree cursor.
 270  */
 271 void
 272 xfs_btree_del_cursor(
 273         xfs_btree_cur_t         *cur,   /* btree cursor */
 274         int                     error); /* del because of error */
 275
 276 /*
 277  * Duplicate the btree cursor.
 278  * Allocate a new one, copy the record, re-get the buffers.
 279  */
 280 int                                     /* error */
 281 xfs_btree_dup_cursor(
 282         xfs_btree_cur_t         *cur,   /* input cursor */
 283         xfs_btree_cur_t         **ncur);/* output cursor */
 284
 285 /*
 286  * Change the cursor to point to the first record in the current block
 287  * at the given level.  Other levels are unaffected.
 288  */
 289 int                                     /* success=1, failure=0 */
 290 xfs_btree_firstrec(
 291         xfs_btree_cur_t         *cur,   /* btree cursor */
 292         int                     level); /* level to change */
 293
 294 /*
 295  * Get a buffer for the block, return it with no data read.
 296  * Long-form addressing.
 297  */
 298 struct xfs_buf *                                /* buffer for fsbno */
 299 xfs_btree_get_bufl(
 300         struct xfs_mount        *mp,    /* file system mount point */
 301         struct xfs_trans        *tp,    /* transaction pointer */
 302         xfs_fsblock_t           fsbno,  /* file system block number */
 303         uint                    lock);  /* lock flags for get_buf */
 304
 305 /*
 306  * Get a buffer for the block, return it with no data read.
 307  * Short-form addressing.
 308  */
 309 struct xfs_buf *                                /* buffer for agno/agbno */
 310 xfs_btree_get_bufs(
 311         struct xfs_mount        *mp,    /* file system mount point */
 312         struct xfs_trans        *tp,    /* transaction pointer */
 313         xfs_agnumber_t          agno,   /* allocation group number */
 314         xfs_agblock_t           agbno,  /* allocation group block number */
 315         uint                    lock);  /* lock flags for get_buf */
 316
 317 /*
 318  * Allocate a new btree cursor.
 319  * The cursor is either for allocation (A) or bmap (B).
 320  */
 321 xfs_btree_cur_t *                       /* new btree cursor */
 322 xfs_btree_init_cursor(
 323         struct xfs_mount        *mp,    /* file system mount point */
 324         struct xfs_trans        *tp,    /* transaction pointer */
 325         struct xfs_buf          *agbp,  /* (A only) buffer for agf structure */
 326         xfs_agnumber_t          agno,   /* (A only) allocation group number */
 327         xfs_btnum_t             btnum,  /* btree identifier */
 328         struct xfs_inode        *ip,    /* (B only) inode owning the btree */
 329         int                     whichfork); /* (B only) data/attr fork */
 330
 331 /*
 332  * Check for the cursor referring to the last block at the given level.
 333  */
 334 int                                     /* 1=is last block, 0=not last block */
 335 xfs_btree_islastblock(
 336         xfs_btree_cur_t         *cur,   /* btree cursor */
 337         int                     level); /* level to check */
 338
 339 /*
 340  * Change the cursor to point to the last record in the current block
 341  * at the given level.  Other levels are unaffected.
 342  */
 343 int                                     /* success=1, failure=0 */
 344 xfs_btree_lastrec(
 345         xfs_btree_cur_t         *cur,   /* btree cursor */
 346         int                     level); /* level to change */
 347
 348 /*
 349  * Compute first and last byte offsets for the fields given.
 350  * Interprets the offsets table, which contains struct field offsets.
 351  */
 352 void
 353 xfs_btree_offsets(
 354         __int64_t               fields, /* bitmask of fields */
 355         const short             *offsets,/* table of field offsets */
 356         int                     nbits,  /* number of bits to inspect */
 357         int                     *first, /* output: first byte offset */
 358         int                     *last); /* output: last byte offset */
 359
 360 /*
 361  * Get a buffer for the block, return it read in.
 362  * Long-form addressing.
 363  */
 364 int                                     /* error */
 365 xfs_btree_read_bufl(
 366         struct xfs_mount        *mp,    /* file system mount point */
 367         struct xfs_trans        *tp,    /* transaction pointer */
 368         xfs_fsblock_t           fsbno,  /* file system block number */
 369         uint                    lock,   /* lock flags for read_buf */
 370         struct xfs_buf          **bpp,  /* buffer for fsbno */
 371         int                     refval);/* ref count value for buffer */
 372
 373 /*
 374  * Get a buffer for the block, return it read in.
 375  * Short-form addressing.
 376  */
 377 int                                     /* error */
 378 xfs_btree_read_bufs(
 379         struct xfs_mount        *mp,    /* file system mount point */
 380         struct xfs_trans        *tp,    /* transaction pointer */
 381         xfs_agnumber_t          agno,   /* allocation group number */
 382         xfs_agblock_t           agbno,  /* allocation group block number */
 383         uint                    lock,   /* lock flags for read_buf */
 384         struct xfs_buf          **bpp,  /* buffer for agno/agbno */
 385         int                     refval);/* ref count value for buffer */
 386
 387 /*
 388  * Read-ahead the block, don't wait for it, don't return a buffer.
 389  * Long-form addressing.
 390  */
 391 void                                    /* error */
 392 xfs_btree_reada_bufl(
 393         struct xfs_mount        *mp,    /* file system mount point */
 394         xfs_fsblock_t           fsbno,  /* file system block number */
 395         xfs_extlen_t            count); /* count of filesystem blocks */
 396
 397 /*
 398  * Read-ahead the block, don't wait for it, don't return a buffer.
 399  * Short-form addressing.
 400  */
 401 void                                    /* error */
 402 xfs_btree_reada_bufs(
 403         struct xfs_mount        *mp,    /* file system mount point */
 404         xfs_agnumber_t          agno,   /* allocation group number */
 405         xfs_agblock_t           agbno,  /* allocation group block number */
 406         xfs_extlen_t            count); /* count of filesystem blocks */
 407
 408 /*
 409  * Read-ahead btree blocks, at the given level.
 410  * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
 411  */
 412 int                                     /* readahead block count */
 413 xfs_btree_readahead_core(
 414         xfs_btree_cur_t         *cur,   /* btree cursor */
 415         int                     lev,    /* level in btree */
 416         int                     lr);    /* left/right bits */
 417
 418 static inline int                       /* readahead block count */
 419 xfs_btree_readahead(
 420         xfs_btree_cur_t         *cur,   /* btree cursor */
 421         int                     lev,    /* level in btree */
 422         int                     lr)     /* left/right bits */
 423 {
 424         if ((cur->bc_ra[lev] | lr) == cur->bc_ra[lev])
 425                 return 0;
 426
 427         return xfs_btree_readahead_core(cur, lev, lr);
 428 }
 429
 430
 431 /*
 432  * Set the buffer for level "lev" in the cursor to bp, releasing
 433  * any previous buffer.
 434  */
 435 void
 436 xfs_btree_setbuf(
 437         xfs_btree_cur_t         *cur,   /* btree cursor */
 438         int                     lev,    /* level in btree */
 439         struct xfs_buf          *bp);   /* new buffer to set */
 440
 441 #endif  /* __KERNEL__ */
 442
 443
 444 /*
 445  * Min and max functions for extlen, agblock, fileoff, and filblks types.
 446  */
 447 #define XFS_EXTLEN_MIN(a,b)     min_t(xfs_extlen_t, (a), (b))
 448 #define XFS_EXTLEN_MAX(a,b)     max_t(xfs_extlen_t, (a), (b))
 449 #define XFS_AGBLOCK_MIN(a,b)    min_t(xfs_agblock_t, (a), (b))
 450 #define XFS_AGBLOCK_MAX(a,b)    max_t(xfs_agblock_t, (a), (b))
 451 #define XFS_FILEOFF_MIN(a,b)    min_t(xfs_fileoff_t, (a), (b))
 452 #define XFS_FILEOFF_MAX(a,b)    max_t(xfs_fileoff_t, (a), (b))
 453 #define XFS_FILBLKS_MIN(a,b)    min_t(xfs_filblks_t, (a), (b))
 454 #define XFS_FILBLKS_MAX(a,b)    max_t(xfs_filblks_t, (a), (b))
 455
 456 #define XFS_FSB_SANITY_CHECK(mp,fsb)    \
 457         (XFS_FSB_TO_AGNO(mp, fsb) < mp->m_sb.sb_agcount && \
 458                 XFS_FSB_TO_AGBNO(mp, fsb) < mp->m_sb.sb_agblocks)
 459
 460 #endif  /* __XFS_BTREE_H__ */