bsd/ufs/ffs/fs.h

   1 /*
   2  * Copyright (c) 2000-2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License.  The rights granted to you under the
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  31 /*
  32  * Copyright (c) 1982, 1986, 1993
  33  *      The Regents of the University of California.  All rights reserved.
  34  *
  35  * Redistribution and use in source and binary forms, with or without
  36  * modification, are permitted provided that the following conditions
  37  * are met:
  38  * 1. Redistributions of source code must retain the above copyright
  39  *    notice, this list of conditions and the following disclaimer.
  40  * 2. Redistributions in binary form must reproduce the above copyright
  41  *    notice, this list of conditions and the following disclaimer in the
  42  *    documentation and/or other materials provided with the distribution.
  43  * 3. All advertising materials mentioning features or use of this software
  44  *    must display the following acknowledgement:
  45  *      This product includes software developed by the University of
  46  *      California, Berkeley and its contributors.
  47  * 4. Neither the name of the University nor the names of its contributors
  48  *    may be used to endorse or promote products derived from this software
  49  *    without specific prior written permission.
  50  *
  51  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  52  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  53  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  54  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  55  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  56  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  57  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  58  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  59  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  60  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  61  * SUCH DAMAGE.
  62  *
  63  *      @(#)fs.h        8.13 (Berkeley) 3/21/95
  64  */
  65 #ifndef _FFS_FS_H_
  66 #define _FFS_FS_H_
  67
  68 #include <sys/appleapiopts.h>
  69
  70 #ifdef __APPLE_API_UNSTABLE
  71 /*
  72  * Each disk drive contains some number of file systems.
  73  * A file system consists of a number of cylinder groups.
  74  * Each cylinder group has inodes and data.
  75  *
  76  * A file system is described by its super-block, which in turn
  77  * describes the cylinder groups.  The super-block is critical
  78  * data and is replicated in each cylinder group to protect against
  79  * catastrophic loss.  This is done at `newfs' time and the critical
  80  * super-block data does not change, so the copies need not be
  81  * referenced further unless disaster strikes.
  82  *
  83  * For file system fs, the offsets of the various blocks of interest
  84  * are given in the super block as:
  85  *      [fs->fs_sblkno]         Super-block
  86  *      [fs->fs_cblkno]         Cylinder group block
  87  *      [fs->fs_iblkno]         Inode blocks
  88  *      [fs->fs_dblkno]         Data blocks
  89  * The beginning of cylinder group cg in fs, is given by
  90  * the ``cgbase(fs, cg)'' macro.
  91  *
  92  * The first boot and super blocks are given in absolute disk addresses.
  93  * The byte-offset forms are preferred, as they don't imply a sector size.
  94  */
  95 #define BBSIZE          8192
  96 #define SBSIZE          8192
  97 #define BBOFF           ((off_t)(0))
  98 #define SBOFF           ((off_t)(BBOFF + BBSIZE))
  99 #define BBLOCK          ((ufs_daddr_t)(0))
 100 #define SBLOCK          ((ufs_daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE))
 101
 102 /*
 103  * Addresses stored in inodes are capable of addressing fragments
 104  * of `blocks'. File system blocks of at most size MAXBSIZE can
 105  * be optionally broken into 2, 4, or 8 pieces, each of which is
 106  * addressible; these pieces may be DEV_BSIZE, or some multiple of
 107  * a DEV_BSIZE unit.
 108  *
 109  * Large files consist of exclusively large data blocks.  To avoid
 110  * undue wasted disk space, the last data block of a small file may be
 111  * allocated as only as many fragments of a large block as are
 112  * necessary.  The file system format retains only a single pointer
 113  * to such a fragment, which is a piece of a single large block that
 114  * has been divided.  The size of such a fragment is determinable from
 115  * information in the inode, using the ``blksize(fs, ip, lbn)'' macro.
 116  *
 117  * The file system records space availability at the fragment level;
 118  * to determine block availability, aligned fragments are examined.
 119  */
 120
 121 /*
 122  * MINBSIZE is the smallest allowable block size.
 123  * In order to insure that it is possible to create files of size
 124  * 2^32 with only two levels of indirection, MINBSIZE is set to 4096.
 125  * MINBSIZE must be big enough to hold a cylinder group block,
 126  * thus changes to (struct cg) must keep its size within MINBSIZE.
 127  * Note that super blocks are always of size SBSIZE,
 128  * and that both SBSIZE and MAXBSIZE must be >= MINBSIZE.
 129  */
 130 #define MINBSIZE        4096
 131
 132 /*
 133  * The path name on which the file system is mounted is maintained
 134  * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
 135  * the super block for this name.
 136  */
 137 #define MAXMNTLEN       512
 138
 139 /*
 140  * The limit on the amount of summary information per file system
 141  * is defined by MAXCSBUFS. It is currently parameterized for a
 142  * size of 128 bytes (2 million cylinder groups on machines with
 143  * 32-bit pointers, and 1 million on 64-bit machines). One pointer
 144  * is taken away to point to an array of cluster sizes that is
 145  * computed as cylinder groups are inspected.
 146  * There is a 128-byte region in the superblock reserved for in-core
 147  * pointers to summary information. Originally this included an array
 148  * of pointers to blocks of struct csum; now there are just three
 149  * pointers and the remaining space is padded with fs_ocsp[].
 150  *
 151  * NOCSPTRS determines the size of this padding. One pointer (fs_csp)
 152  * is taken away to point to a contiguous array of struct csum for
 153  * all cylinder groups; a second (fs_maxcluster) points to an array
 154  * of cluster sizes that is computed as cylinder groups are inspected,
 155  * and the third points to an array that tracks the creation of new
 156  * directories.
 157  */
 158 #define NOCSPTRS ((128 / sizeof(void *)) - 3)
 159
 160 /*
 161  * A summary of contiguous blocks of various sizes is maintained
 162  * in each cylinder group. Normally this is set by the initial
 163  * value of fs_maxcontig. To conserve space, a maximum summary size
 164  * is set by FS_MAXCONTIG.
 165  */
 166 #define FS_MAXCONTIG    16
 167
 168 /*
 169  * MINFREE gives the minimum acceptable percentage of file system
 170  * blocks which may be free. If the freelist drops below this level
 171  * only the superuser may continue to allocate blocks. This may
 172  * be set to 0 if no reserve of free blocks is deemed necessary,
 173  * however throughput drops by fifty percent if the file system
 174  * is run at between 95% and 100% full; thus the minimum default
 175  * value of fs_minfree is 5%. However, to get good clustering
 176  * performance, 10% is a better choice. hence we use 10% as our
 177  * default value. With 10% free space, fragmentation is not a
 178  * problem, so we choose to optimize for time.
 179  */
 180 #define MINFREE         5
 181 #define DEFAULTOPT      FS_OPTTIME
 182
 183 /* Grigoriy Orlov <gluk@ptci.ru> has done some extensive work to fine
 184  * tune the layout preferences for directories within a filesystem.
 185  * His algorithm can be tuned by adjusting the following parameters
 186  * which tell the system the average file size and the average number
 187  * of files per directory. These defaults are well selected for typical
 188  * filesystems, but may need to be tuned for odd cases like filesystems
 189  * being used for squid caches or news spools.
 190  */
 191 #define AVFILESIZ       16384
 192 #define AFPDIR          64
 193
 194 /*
 195  * Per cylinder group information; summarized in blocks allocated
 196  * from first cylinder group data blocks.  These blocks have to be
 197  * read in from fs_csaddr (size fs_cssize) in addition to the
 198  * super block.
 199  */
 200 struct csum {
 201         int32_t cs_ndir;                /* number of directories */
 202         int32_t cs_nbfree;              /* number of free blocks */
 203         int32_t cs_nifree;              /* number of free inodes */
 204         int32_t cs_nffree;              /* number of free frags */
 205 };
 206
 207 /*
 208  * Super block for an FFS file system.
 209  */
 210 struct fs {
 211         int32_t  fs_firstfield;         /* historic file system linked list, */
 212         int32_t  fs_unused_1;           /*     used for incore super blocks */
 213         ufs_daddr_t fs_sblkno;          /* addr of super-block in filesys */
 214         ufs_daddr_t fs_cblkno;          /* offset of cyl-block in filesys */
 215         ufs_daddr_t fs_iblkno;          /* offset of inode-blocks in filesys */
 216         ufs_daddr_t fs_dblkno;          /* offset of first data after cg */
 217         int32_t  fs_cgoffset;           /* cylinder group offset in cylinder */
 218         int32_t  fs_cgmask;             /* used to calc mod fs_ntrak */
 219         time_t   fs_time;               /* last time written */
 220         int32_t  fs_size;               /* number of blocks in fs */
 221         int32_t  fs_dsize;              /* number of data blocks in fs */
 222         int32_t  fs_ncg;                /* number of cylinder groups */
 223         int32_t  fs_bsize;              /* size of basic blocks in fs */
 224         int32_t  fs_fsize;              /* size of frag blocks in fs */
 225         int32_t  fs_frag;               /* number of frags in a block in fs */
 226 /* these are configuration parameters */
 227         int32_t  fs_minfree;            /* minimum percentage of free blocks */
 228         int32_t  fs_rotdelay;           /* num of ms for optimal next block */
 229         int32_t  fs_rps;                /* disk revolutions per second */
 230 /* these fields can be computed from the others */
 231         int32_t  fs_bmask;              /* ``blkoff'' calc of blk offsets */
 232         int32_t  fs_fmask;              /* ``fragoff'' calc of frag offsets */
 233         int32_t  fs_bshift;             /* ``lblkno'' calc of logical blkno */
 234         int32_t  fs_fshift;             /* ``numfrags'' calc number of frags */
 235 /* these are configuration parameters */
 236         int32_t  fs_maxcontig;          /* max number of contiguous blks */
 237         int32_t  fs_maxbpg;             /* max number of blks per cyl group */
 238 /* these fields can be computed from the others */
 239         int32_t  fs_fragshift;          /* block to frag shift */
 240         int32_t  fs_fsbtodb;            /* fsbtodb and dbtofsb shift constant */
 241         int32_t  fs_sbsize;             /* actual size of super block */
 242         int32_t  fs_csmask;             /* csum block offset (now unused) */
 243         int32_t  fs_csshift;            /* csum block number (now unused) */
 244         int32_t  fs_nindir;             /* value of NINDIR */
 245         int32_t  fs_inopb;              /* value of INOPB */
 246         int32_t  fs_nspf;               /* value of NSPF */
 247 /* yet another configuration parameter */
 248         int32_t  fs_optim;              /* optimization preference, see below */
 249 /* these fields are derived from the hardware */
 250         int32_t  fs_npsect;             /* # sectors/track including spares */
 251         int32_t  fs_interleave;         /* hardware sector interleave */
 252         int32_t  fs_trackskew;          /* sector 0 skew, per track */
 253         int32_t  fs_headswitch;         /* head switch time, usec */
 254         int32_t  fs_trkseek;            /* track-to-track seek, usec */
 255 /* sizes determined by number of cylinder groups and their sizes */
 256         ufs_daddr_t fs_csaddr;          /* blk addr of cyl grp summary area */
 257         int32_t  fs_cssize;             /* size of cyl grp summary area */
 258         int32_t  fs_cgsize;             /* cylinder group size */
 259 /* these fields are derived from the hardware */
 260         int32_t  fs_ntrak;              /* tracks per cylinder */
 261         int32_t  fs_nsect;              /* sectors per track */
 262         int32_t  fs_spc;                        /* sectors per cylinder */
 263 /* this comes from the disk driver partitioning */
 264         int32_t  fs_ncyl;               /* cylinders in file system */
 265 /* these fields can be computed from the others */
 266         int32_t  fs_cpg;                        /* cylinders per group */
 267         int32_t  fs_ipg;                        /* inodes per group */
 268         int32_t  fs_fpg;                        /* blocks per group * fs_frag */
 269 /* this data must be re-computed after crashes */
 270         struct  csum fs_cstotal;        /* cylinder summary information */
 271 /* these fields are cleared at mount time */
 272         int8_t   fs_fmod;               /* super block modified flag */
 273         int8_t   fs_clean;              /* file system is clean flag */
 274         int8_t   fs_ronly;              /* mounted read-only flag */
 275         int8_t   fs_flags;              /* currently unused flag */
 276         u_char   fs_fsmnt[MAXMNTLEN];   /* name mounted on */
 277 /* these fields retain the current block allocation info */
 278         int32_t  fs_cgrotor;            /* last cg searched */
 279         void    *fs_ocsp[NOCSPTRS];     /* list of fs_cs info buffers */
 280         u_int8_t *fs_contigdirs;        /* # of contiguously allocated dirs */
 281         struct  csum *fs_csp;           /* list of fs_cs info buffers */
 282         int32_t  *fs_maxcluster;        /* max cluster in each cyl group */
 283         int32_t  fs_cpc;                /* cyl per cycle in postbl */
 284         int16_t  fs_opostbl[16][8];     /* old rotation block list head */
 285         int32_t  fs_avgfilesize;        /* expected average file size */
 286         int32_t  fs_avgfpdir;           /* expected # of files per directory */
 287         int32_t  fs_sparecon[48];       /* reserved for future constants */
 288         int32_t  fs_contigsumsize;      /* size of cluster summary array */
 289         int32_t  fs_maxsymlinklen;      /* max length of an internal symlink */
 290         int32_t  fs_inodefmt;           /* format of on-disk inodes */
 291         u_int64_t fs_maxfilesize;       /* maximum representable file size */
 292         int64_t  fs_qbmask;             /* ~fs_bmask for use with 64-bit size */
 293         int64_t  fs_qfmask;             /* ~fs_fmask for use with 64-bit size */
 294         int32_t  fs_state;              /* validate fs_clean field */
 295         int32_t  fs_postblformat;       /* format of positional layout tables */
 296         int32_t  fs_nrpos;              /* number of rotational positions */
 297         int32_t  fs_postbloff;          /* (u_int16) rotation block list head */
 298         int32_t  fs_rotbloff;           /* (u_int8) blocks for each rotation */
 299         int32_t  fs_magic;              /* magic number */
 300         u_int8_t fs_space[1];           /* list of blocks for each rotation */
 301 /* actually longer */
 302 };
 303
 304 /*
 305  * Filesystem identification
 306  */
 307 #define FS_MAGIC        0x011954        /* the fast filesystem magic number */
 308 #define FS_OKAY         0x7c269d38      /* superblock checksum */
 309 #define FS_42INODEFMT   -1              /* 4.2BSD inode format */
 310 #define FS_44INODEFMT   2               /* 4.4BSD inode format */
 311 /*
 312  * Preference for optimization.
 313  */
 314 #define FS_OPTTIME      0       /* minimize allocation time */
 315 #define FS_OPTSPACE     1       /* minimize disk fragmentation */
 316
 317 /*
 318  * Rotational layout table format types
 319  */
 320 #define FS_42POSTBLFMT          -1      /* 4.2BSD rotational table format */
 321 #define FS_DYNAMICPOSTBLFMT     1       /* dynamic rotational table format */
 322 /*
 323  * Macros for access to superblock array structures
 324  */
 325 #define fs_postbl(fs, cylno) \
 326     (((fs)->fs_postblformat == FS_42POSTBLFMT) \
 327     ? ((fs)->fs_opostbl[cylno]) \
 328     : ((int16_t *)((u_int8_t *)(fs) + \
 329         (fs)->fs_postbloff) + (cylno) * (fs)->fs_nrpos))
 330 #define fs_rotbl(fs) \
 331     (((fs)->fs_postblformat == FS_42POSTBLFMT) \
 332     ? ((fs)->fs_space) \
 333     : ((u_int8_t *)((u_int8_t *)(fs) + (fs)->fs_rotbloff)))
 334
 335 /*
 336  * The size of a cylinder group is calculated by CGSIZE. The maximum size
 337  * is limited by the fact that cylinder groups are at most one block.
 338  * Its size is derived from the size of the maps maintained in the
 339  * cylinder group and the (struct cg) size.
 340  */
 341 #define CGSIZE(fs) \
 342     /* base cg */       (sizeof(struct cg) + sizeof(int32_t) + \
 343     /* blktot size */   (fs)->fs_cpg * sizeof(int32_t) + \
 344     /* blks size */     (fs)->fs_cpg * (fs)->fs_nrpos * sizeof(int16_t) + \
 345     /* inode map */     howmany((fs)->fs_ipg, NBBY) + \
 346     /* block map */     howmany((fs)->fs_cpg * (fs)->fs_spc / NSPF(fs), NBBY) +\
 347     /* if present */    ((fs)->fs_contigsumsize <= 0 ? 0 : \
 348     /* cluster sum */   (fs)->fs_contigsumsize * sizeof(int32_t) + \
 349     /* cluster map */   howmany((fs)->fs_cpg * (fs)->fs_spc / NSPB(fs), NBBY)))
 350
 351 /*
 352  * Convert cylinder group to base address of its global summary info.
 353  *
 354  * N.B. This macro assumes that sizeof(struct csum) is a power of two.
 355  */
 356 #define fs_cs(fs, indx) fs_csp[indx]
 357
 358 /*
 359  * Cylinder group block for a file system.
 360  */
 361 #define CG_MAGIC        0x090255
 362 struct cg {
 363         int32_t  cg_firstfield;         /* historic cyl groups linked list */
 364         int32_t  cg_magic;              /* magic number */
 365         time_t   cg_time;               /* time last written */
 366         int32_t  cg_cgx;                /* we are the cgx'th cylinder group */
 367         int16_t  cg_ncyl;               /* number of cyl's this cg */
 368         int16_t  cg_niblk;              /* number of inode blocks this cg */
 369         int32_t  cg_ndblk;              /* number of data blocks this cg */
 370         struct  csum cg_cs;             /* cylinder summary information */
 371         int32_t  cg_rotor;              /* position of last used block */
 372         int32_t  cg_frotor;             /* position of last used frag */
 373         int32_t  cg_irotor;             /* position of last used inode */
 374         int32_t  cg_frsum[MAXFRAG];     /* counts of available frags */
 375         int32_t  cg_btotoff;            /* (int32) block totals per cylinder */
 376         int32_t  cg_boff;               /* (u_int16) free block positions */
 377         int32_t  cg_iusedoff;           /* (u_int8) used inode map */
 378         int32_t  cg_freeoff;            /* (u_int8) free block map */
 379         int32_t  cg_nextfreeoff;        /* (u_int8) next available space */
 380         int32_t  cg_clustersumoff;      /* (u_int32) counts of avail clusters */
 381         int32_t  cg_clusteroff;         /* (u_int8) free cluster map */
 382         int32_t  cg_nclusterblks;       /* number of clusters this cg */
 383         int32_t  cg_sparecon[13];       /* reserved for future use */
 384         u_int8_t cg_space[1];           /* space for cylinder group maps */
 385 /* actually longer */
 386 };
 387
 388 /*
 389  * Macros for access to cylinder group array structures
 390  */
 391 #define cg_blktot(cgp) \
 392     (((cgp)->cg_magic != CG_MAGIC) \
 393     ? (((struct ocg *)(cgp))->cg_btot) \
 394     : ((int32_t *)((u_int8_t *)(cgp) + (cgp)->cg_btotoff)))
 395 #define cg_blks(fs, cgp, cylno) \
 396     (((cgp)->cg_magic != CG_MAGIC) \
 397     ? (((struct ocg *)(cgp))->cg_b[cylno]) \
 398     : ((int16_t *)((u_int8_t *)(cgp) + \
 399         (cgp)->cg_boff) + (cylno) * (fs)->fs_nrpos))
 400 #define cg_inosused(cgp) \
 401     (((cgp)->cg_magic != CG_MAGIC) \
 402     ? (((struct ocg *)(cgp))->cg_iused) \
 403     : ((u_int8_t *)((u_int8_t *)(cgp) + (cgp)->cg_iusedoff)))
 404 #define cg_blksfree(cgp) \
 405     (((cgp)->cg_magic != CG_MAGIC) \
 406     ? (((struct ocg *)(cgp))->cg_free) \
 407     : ((u_int8_t *)((u_int8_t *)(cgp) + (cgp)->cg_freeoff)))
 408 #define cg_chkmagic(cgp) \
 409     ((cgp)->cg_magic == CG_MAGIC || ((struct ocg *)(cgp))->cg_magic == CG_MAGIC)
 410 #define cg_clustersfree(cgp) \
 411     ((u_int8_t *)((u_int8_t *)(cgp) + (cgp)->cg_clusteroff))
 412 #define cg_clustersum(cgp) \
 413     ((int32_t *)((u_int8_t *)(cgp) + (cgp)->cg_clustersumoff))
 414
 415 /*
 416  * The following structure is defined
 417  * for compatibility with old file systems.
 418  */
 419 struct ocg {
 420         int32_t  cg_firstfield;         /* historic linked list of cyl groups */
 421         int32_t  cg_unused_1;           /*     used for incore cyl groups */
 422         time_t   cg_time;               /* time last written */
 423         int32_t  cg_cgx;                /* we are the cgx'th cylinder group */
 424         int16_t  cg_ncyl;               /* number of cyl's this cg */
 425         int16_t  cg_niblk;              /* number of inode blocks this cg */
 426         int32_t  cg_ndblk;              /* number of data blocks this cg */
 427         struct  csum cg_cs;             /* cylinder summary information */
 428         int32_t  cg_rotor;              /* position of last used block */
 429         int32_t  cg_frotor;             /* position of last used frag */
 430         int32_t  cg_irotor;             /* position of last used inode */
 431         int32_t  cg_frsum[8];           /* counts of available frags */
 432         int32_t  cg_btot[32];           /* block totals per cylinder */
 433         int16_t  cg_b[32][8];           /* positions of free blocks */
 434         u_int8_t cg_iused[256];         /* used inode map */
 435         int32_t  cg_magic;              /* magic number */
 436         u_int8_t cg_free[1];            /* free block map */
 437 /* actually longer */
 438 };
 439
 440 /*
 441  * Turn file system block numbers into disk block addresses.
 442  * This maps file system blocks to device size blocks.
 443  */
 444 #define fsbtodb(fs, b)  ((b) << (fs)->fs_fsbtodb)
 445 #define dbtofsb(fs, b)  ((b) >> (fs)->fs_fsbtodb)
 446
 447 /*
 448  * Cylinder group macros to locate things in cylinder groups.
 449  * They calc file system addresses of cylinder group data structures.
 450  */
 451 #define cgbase(fs, c)   ((ufs_daddr_t)((fs)->fs_fpg * (c)))
 452 #define cgdmin(fs, c)   (cgstart(fs, c) + (fs)->fs_dblkno)      /* 1st data */
 453 #define cgimin(fs, c)   (cgstart(fs, c) + (fs)->fs_iblkno)      /* inode blk */
 454 #define cgsblock(fs, c) (cgstart(fs, c) + (fs)->fs_sblkno)      /* super blk */
 455 #define cgtod(fs, c)    (cgstart(fs, c) + (fs)->fs_cblkno)      /* cg block */
 456 #define cgstart(fs, c)                                                  \
 457         (cgbase(fs, c) + (fs)->fs_cgoffset * ((c) & ~((fs)->fs_cgmask)))
 458
 459 /*
 460  * Macros for handling inode numbers:
 461  *     inode number to file system block offset.
 462  *     inode number to cylinder group number.
 463  *     inode number to file system block address.
 464  */
 465 #define ino_to_cg(fs, x)        ((x) / (fs)->fs_ipg)
 466 #define ino_to_fsba(fs, x)                                              \
 467         ((ufs_daddr_t)(cgimin(fs, ino_to_cg(fs, x)) +                   \
 468             (blkstofrags((fs), (((x) % (fs)->fs_ipg) / INOPB(fs))))))
 469 #define ino_to_fsbo(fs, x)      ((x) % INOPB(fs))
 470
 471 /*
 472  * Give cylinder group number for a file system block.
 473  * Give cylinder group block number for a file system block.
 474  */
 475 #define dtog(fs, d)     ((d) / (fs)->fs_fpg)
 476 #define dtogd(fs, d)    ((d) % (fs)->fs_fpg)
 477
 478 /*
 479  * Extract the bits for a block from a map.
 480  * Compute the cylinder and rotational position of a cyl block addr.
 481  */
 482 #define blkmap(fs, map, loc) \
 483     (((map)[(loc) / NBBY] >> ((loc) % NBBY)) & (0xff >> (NBBY - (fs)->fs_frag)))
 484 #define cbtocylno(fs, bno) \
 485     ((bno) * NSPF(fs) / (fs)->fs_spc)
 486 #define cbtorpos(fs, bno) \
 487     (((bno) * NSPF(fs) % (fs)->fs_spc / (fs)->fs_nsect * (fs)->fs_trackskew + \
 488      (bno) * NSPF(fs) % (fs)->fs_spc % (fs)->fs_nsect * (fs)->fs_interleave) % \
 489      (fs)->fs_nsect * (fs)->fs_nrpos / (fs)->fs_npsect)
 490
 491 /*
 492  * The following macros optimize certain frequently calculated
 493  * quantities by using shifts and masks in place of divisions
 494  * modulos and multiplications.
 495  */
 496 #define blkoff(fs, loc)         /* calculates (loc % fs->fs_bsize) */ \
 497         ((loc) & (fs)->fs_qbmask)
 498 #define fragoff(fs, loc)        /* calculates (loc % fs->fs_fsize) */ \
 499         ((loc) & (fs)->fs_qfmask)
 500 #define lblktosize(fs, blk)     /* calculates (blk * fs->fs_bsize) */ \
 501         ((blk) << (fs)->fs_bshift)
 502 #define lblkno(fs, loc)         /* calculates (loc / fs->fs_bsize) */ \
 503         ((loc) >> (fs)->fs_bshift)
 504 #define numfrags(fs, loc)       /* calculates (loc / fs->fs_fsize) */ \
 505         ((loc) >> (fs)->fs_fshift)
 506 #define blkroundup(fs, size)    /* calculates roundup(size, fs->fs_bsize) */ \
 507         (((size) + (fs)->fs_qbmask) & (fs)->fs_bmask)
 508 #define fragroundup(fs, size)   /* calculates roundup(size, fs->fs_fsize) */ \
 509         (((size) + (fs)->fs_qfmask) & (fs)->fs_fmask)
 510 #define fragstoblks(fs, frags)  /* calculates (frags / fs->fs_frag) */ \
 511         ((frags) >> (fs)->fs_fragshift)
 512 #define blkstofrags(fs, blks)   /* calculates (blks * fs->fs_frag) */ \
 513         ((blks) << (fs)->fs_fragshift)
 514 #define fragnum(fs, fsb)        /* calculates (fsb % fs->fs_frag) */ \
 515         ((fsb) & ((fs)->fs_frag - 1))
 516 #define blknum(fs, fsb)         /* calculates rounddown(fsb, fs->fs_frag) */ \
 517         ((fsb) &~ ((fs)->fs_frag - 1))
 518
 519 /*
 520  * Determine the number of available frags given a
 521  * percentage to hold in reserve.
 522  */
 523 #define freespace(fs, percentreserved) \
 524         (blkstofrags((fs), (fs)->fs_cstotal.cs_nbfree) + \
 525         (fs)->fs_cstotal.cs_nffree - ((fs)->fs_dsize * (percentreserved) / 100))
 526
 527 /*
 528  * Determining the size of a file block in the file system.
 529  */
 530 #define blksize(fs, ip, lbn) \
 531         (((lbn) >= NDADDR || (ip)->i_size >= ((lbn) + 1) << (fs)->fs_bshift) \
 532             ? (fs)->fs_bsize \
 533             : (fragroundup(fs, blkoff(fs, (ip)->i_size))))
 534 #define dblksize(fs, dip, lbn) \
 535         (((lbn) >= NDADDR || (dip)->di_size >= ((lbn) + 1) << (fs)->fs_bshift) \
 536             ? (fs)->fs_bsize \
 537             : (fragroundup(fs, blkoff(fs, (dip)->di_size))))
 538
 539 /*
 540  * Number of disk sectors per block/fragment; assumes DEV_BSIZE byte
 541  * sector size.
 542  */
 543 #define NSPB(fs)        ((fs)->fs_nspf << (fs)->fs_fragshift)
 544 #define NSPF(fs)        ((fs)->fs_nspf)
 545
 546 /*
 547  * Number of inodes in a secondary storage block/fragment.
 548  */
 549 #define INOPB(fs)       ((fs)->fs_inopb)
 550 #define INOPF(fs)       ((fs)->fs_inopb >> (fs)->fs_fragshift)
 551
 552 /*
 553  * Number of indirects in a file system block.
 554  */
 555 #define NINDIR(fs)      ((fs)->fs_nindir)
 556
 557 /*
 558  * This macro controls whether the file system format is byte swapped or not.
 559  * At NeXT, all little endian machines read and write big endian file systems.
 560  */
 561 #define BIG_ENDIAN_FS   (__LITTLE_ENDIAN__)
 562
 563 #ifdef __APPLE_API_PRIVATE
 564 extern int inside[], around[];
 565 extern u_char *fragtbl[];
 566 #endif /* __APPLE_API_PRIVATE */
 567
 568
 569 /*
 570  * UFS Label:
 571  *   The purpose of this label is to name a UFS/FFS filesystem.  The label
 572  *   is located at offset 7K (BBSIZE=8K - UFS_LABEL_SIZE=1K = 7K) of the
 573  *   partition.  The first 7K is still available for boot blocks.
 574  */
 575
 576 #define UFS_LABEL_MAGIC         { 'L', 'A', 'B', 'L' }
 577 #define UFS_LABEL_SIZE          1024
 578 #define UFS_LABEL_OFFSET        (BBSIZE - UFS_LABEL_SIZE) /* top 1K */
 579 #define UFS_LABEL_VERSION       1
 580 #define UFS_MAX_LABEL_NAME      512
 581
 582 struct ufslabel {
 583     u_int32_t           ul_magic;
 584     u_int16_t           ul_checksum;    /* checksum over entire label*/
 585     u_int32_t           ul_version;     /* label version */
 586     u_int32_t           ul_time;        /* creation time */
 587     u_int16_t           ul_namelen;     /* filesystem name length */
 588     u_char              ul_name[UFS_MAX_LABEL_NAME]; /* filesystem name */
 589     u_int64_t           ul_uuid;        /* filesystem uuid */
 590     u_char              ul_reserved[24];/* reserved for future use */
 591     u_char              ul_unused[460]; /* pad out to 1K */
 592 };
 593
 594 #endif /* __APPLE_API_UNSTABLE */
 595 #endif /* ! _FFS_FS_H_ */