fs.h revision 1.20
1 /* $NetBSD: fs.h,v 1.20 2001/09/06 02:16:02 lukem Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)fs.h 8.13 (Berkeley) 3/21/95 36 */ 37 38 #ifndef _UFS_FFS_FS_H_ 39 #define _UFS_FFS_FS_H_ 40 41 #include <ufs/ufs/dinode.h> 42 43 /* 44 * Each disk drive contains some number of file systems. 45 * A file system consists of a number of cylinder groups. 46 * Each cylinder group has inodes and data. 47 * 48 * A file system is described by its super-block, which in turn 49 * describes the cylinder groups. The super-block is critical 50 * data and is replicated in each cylinder group to protect against 51 * catastrophic loss. This is done at `newfs' time and the critical 52 * super-block data does not change, so the copies need not be 53 * referenced further unless disaster strikes. 54 * 55 * For file system fs, the offsets of the various blocks of interest 56 * are given in the super block as: 57 * [fs->fs_sblkno] Super-block 58 * [fs->fs_cblkno] Cylinder group block 59 * [fs->fs_iblkno] Inode blocks 60 * [fs->fs_dblkno] Data blocks 61 * The beginning of cylinder group cg in fs, is given by 62 * the ``cgbase(fs, cg)'' macro. 63 * 64 * The first boot and super blocks are given in absolute disk addresses. 65 * The byte-offset forms are preferred, as they don't imply a sector size. 66 */ 67 #define BBSIZE 8192 68 #define SBSIZE 8192 69 #define BBOFF ((off_t)(0)) 70 #define SBOFF ((off_t)(BBOFF + BBSIZE)) 71 #define BBLOCK ((ufs_daddr_t)(0)) 72 #define SBLOCK ((ufs_daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE)) 73 74 /* 75 * Addresses stored in inodes are capable of addressing fragments 76 * of `blocks'. File system blocks of at most size MAXBSIZE can 77 * be optionally broken into 2, 4, or 8 pieces, each of which is 78 * addressable; these pieces may be DEV_BSIZE, or some multiple of 79 * a DEV_BSIZE unit. 80 * 81 * Large files consist of exclusively large data blocks. To avoid 82 * undue wasted disk space, the last data block of a small file may be 83 * allocated as only as many fragments of a large block as are 84 * necessary. The file system format retains only a single pointer 85 * to such a fragment, which is a piece of a single large block that 86 * has been divided. The size of such a fragment is determinable from 87 * information in the inode, using the ``blksize(fs, ip, lbn)'' macro. 88 * 89 * The file system records space availability at the fragment level; 90 * to determine block availability, aligned fragments are examined. 91 */ 92 93 /* 94 * MINBSIZE is the smallest allowable block size. 95 * In order to insure that it is possible to create files of size 96 * 2^32 with only two levels of indirection, MINBSIZE is set to 4096. 97 * MINBSIZE must be big enough to hold a cylinder group block, 98 * thus changes to (struct cg) must keep its size within MINBSIZE. 99 * Note that super blocks are always of size SBSIZE, 100 * and that both SBSIZE and MAXBSIZE must be >= MINBSIZE. 101 */ 102 #define MINBSIZE 4096 103 104 /* 105 * The path name on which the file system is mounted is maintained 106 * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in 107 * the super block for this name. 108 */ 109 #define MAXMNTLEN 512 110 111 /* 112 * There is a 128-byte region in the superblock reserved for in-core 113 * pointers to summary information. Originally this included an array 114 * of pointers to blocks of struct csum; now there are just three 115 * pointers and the remaining space is padded with fs_ocsp[]. 116 * NOCSPTRS determines the size of this padding. One pointer (fs_csp) 117 * is taken away to point to a contiguous array of struct csum for 118 * all cylinder groups; a second (fs_maxcluster) points to an array 119 * of cluster sizes that is computed as cylinder groups are inspected; 120 * and the third points to an array that tracks the creation of new 121 * directories. 122 */ 123 #define NOCSPTRS ((128 / sizeof(void *)) - 3) 124 125 /* 126 * A summary of contiguous blocks of various sizes is maintained 127 * in each cylinder group. Normally this is set by the initial 128 * value of fs_maxcontig. To conserve space, a maximum summary size 129 * is set by FS_MAXCONTIG. 130 */ 131 #define FS_MAXCONTIG 16 132 133 /* 134 * MINFREE gives the minimum acceptable percentage of file system 135 * blocks which may be free. If the freelist drops below this level 136 * only the superuser may continue to allocate blocks. This may 137 * be set to 0 if no reserve of free blocks is deemed necessary, 138 * however throughput drops by fifty percent if the file system 139 * is run at between 95% and 100% full; thus the minimum default 140 * value of fs_minfree is 5%. However, to get good clustering 141 * performance, 10% is a better choice. hence we use 10% as our 142 * default value. With 10% free space, fragmentation is not a 143 * problem, so we choose to optimize for time. 144 */ 145 #define MINFREE 5 146 #define DEFAULTOPT FS_OPTTIME 147 148 /* 149 * Grigoriy Orlov <gluk (at) ptci.ru> has done some extensive work to fine 150 * tune the layout preferences for directories within a filesystem. 151 * His algorithm can be tuned by adjusting the following parameters 152 * which tell the system the average file size and the average number 153 * of files per directory. These defaults are well selected for typical 154 * filesystems, but may need to be tuned for odd cases like filesystems 155 * being used for sqiud caches or news spools. 156 */ 157 #define AVFILESIZ 16384 /* expected average file size */ 158 #define AFPDIR 64 /* expected number of files per directory */ 159 160 /* 161 * Per cylinder group information; summarized in blocks allocated 162 * from first cylinder group data blocks. These blocks have to be 163 * read in from fs_csaddr (size fs_cssize) in addition to the 164 * super block. 165 */ 166 struct csum { 167 int32_t cs_ndir; /* number of directories */ 168 int32_t cs_nbfree; /* number of free blocks */ 169 int32_t cs_nifree; /* number of free inodes */ 170 int32_t cs_nffree; /* number of free frags */ 171 }; 172 173 /* 174 * Super block for an FFS file system in memory. 175 */ 176 struct fs { 177 int32_t fs_firstfield; /* historic file system linked list, */ 178 int32_t fs_unused_1; /* used for incore super blocks */ 179 ufs_daddr_t fs_sblkno; /* addr of super-block in filesys */ 180 ufs_daddr_t fs_cblkno; /* offset of cyl-block in filesys */ 181 ufs_daddr_t fs_iblkno; /* offset of inode-blocks in filesys */ 182 ufs_daddr_t fs_dblkno; /* offset of first data after cg */ 183 int32_t fs_cgoffset; /* cylinder group offset in cylinder */ 184 int32_t fs_cgmask; /* used to calc mod fs_ntrak */ 185 int32_t fs_time; /* last time written */ 186 int32_t fs_size; /* number of blocks in fs */ 187 int32_t fs_dsize; /* number of data blocks in fs */ 188 int32_t fs_ncg; /* number of cylinder groups */ 189 int32_t fs_bsize; /* size of basic blocks in fs */ 190 int32_t fs_fsize; /* size of frag blocks in fs */ 191 int32_t fs_frag; /* number of frags in a block in fs */ 192 /* these are configuration parameters */ 193 int32_t fs_minfree; /* minimum percentage of free blocks */ 194 int32_t fs_rotdelay; /* num of ms for optimal next block */ 195 int32_t fs_rps; /* disk revolutions per second */ 196 /* these fields can be computed from the others */ 197 int32_t fs_bmask; /* ``blkoff'' calc of blk offsets */ 198 int32_t fs_fmask; /* ``fragoff'' calc of frag offsets */ 199 int32_t fs_bshift; /* ``lblkno'' calc of logical blkno */ 200 int32_t fs_fshift; /* ``numfrags'' calc number of frags */ 201 /* these are configuration parameters */ 202 int32_t fs_maxcontig; /* max number of contiguous blks */ 203 int32_t fs_maxbpg; /* max number of blks per cyl group */ 204 /* these fields can be computed from the others */ 205 int32_t fs_fragshift; /* block to frag shift */ 206 int32_t fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */ 207 int32_t fs_sbsize; /* actual size of super block */ 208 int32_t fs_csmask; /* csum block offset (now unused) */ 209 int32_t fs_csshift; /* csum block number (now unused) */ 210 int32_t fs_nindir; /* value of NINDIR */ 211 int32_t fs_inopb; /* value of INOPB */ 212 int32_t fs_nspf; /* value of NSPF */ 213 /* yet another configuration parameter */ 214 int32_t fs_optim; /* optimization preference, see below */ 215 /* these fields are derived from the hardware */ 216 int32_t fs_npsect; /* # sectors/track including spares */ 217 int32_t fs_interleave; /* hardware sector interleave */ 218 int32_t fs_trackskew; /* sector 0 skew, per track */ 219 /* fs_id takes the space of the unused fs_headswitch and fs_trkseek fields */ 220 int32_t fs_id[2]; /* unique file system id */ 221 /* sizes determined by number of cylinder groups and their sizes */ 222 ufs_daddr_t fs_csaddr; /* blk addr of cyl grp summary area */ 223 int32_t fs_cssize; /* size of cyl grp summary area */ 224 int32_t fs_cgsize; /* cylinder group size */ 225 /* these fields are derived from the hardware */ 226 int32_t fs_ntrak; /* tracks per cylinder */ 227 int32_t fs_nsect; /* sectors per track */ 228 int32_t fs_spc; /* sectors per cylinder */ 229 /* this comes from the disk driver partitioning */ 230 int32_t fs_ncyl; /* cylinders in file system */ 231 /* these fields can be computed from the others */ 232 int32_t fs_cpg; /* cylinders per group */ 233 int32_t fs_ipg; /* inodes per group */ 234 int32_t fs_fpg; /* blocks per group * fs_frag */ 235 /* this data must be re-computed after crashes */ 236 struct csum fs_cstotal; /* cylinder summary information */ 237 /* these fields are cleared at mount time */ 238 int8_t fs_fmod; /* super block modified flag */ 239 int8_t fs_clean; /* file system is clean flag */ 240 int8_t fs_ronly; /* mounted read-only flag */ 241 int8_t fs_flags; /* see FS_ flags below */ 242 u_char fs_fsmnt[MAXMNTLEN]; /* name mounted on */ 243 /* these fields retain the current block allocation info */ 244 int32_t fs_cgrotor; /* last cg searched */ 245 void *fs_ocsp[NOCSPTRS]; /* padding; was list of fs_cs buffers */ 246 u_int16_t *fs_contigdirs; /* # of contiguously allocated dirs */ 247 struct csum *fs_csp; /* cg summary info buffer for fs_cs */ 248 int32_t *fs_maxcluster; /* max cluster in each cyl group */ 249 int32_t fs_cpc; /* cyl per cycle in postbl */ 250 int16_t fs_opostbl[16][8]; /* old rotation block list head */ 251 int32_t fs_snapinum[20]; /* RESERVED for snapshot inode nums */ 252 int32_t fs_avgfilesize; /* expected average file size */ 253 int32_t fs_avgfpdir; /* expected # of files per directory */ 254 int32_t fs_sparecon[28]; /* RESERVED for future constants */ 255 int32_t fs_contigsumsize; /* size of cluster summary array */ 256 int32_t fs_maxsymlinklen; /* max length of an internal symlink */ 257 int32_t fs_inodefmt; /* format of on-disk inodes */ 258 u_int64_t fs_maxfilesize; /* maximum representable file size */ 259 int64_t fs_qbmask; /* ~fs_bmask for use with 64-bit size */ 260 int64_t fs_qfmask; /* ~fs_fmask for use with 64-bit size */ 261 int32_t fs_state; /* validate fs_clean field (UNUSED) */ 262 int32_t fs_postblformat; /* format of positional layout tables */ 263 int32_t fs_nrpos; /* number of rotational positions */ 264 int32_t fs_postbloff; /* (u_int16) rotation block list head */ 265 int32_t fs_rotbloff; /* (u_int8) blocks for each rotation */ 266 int32_t fs_magic; /* magic number */ 267 u_int8_t fs_space[1]; /* list of blocks for each rotation */ 268 /* actually longer */ 269 }; 270 271 /* 272 * File system identification 273 */ 274 #define FS_MAGIC 0x011954 /* the fast file system magic number */ 275 #define FS_OKAY 0x7c269d38 /* superblock checksum */ 276 #define FS_42INODEFMT -1 /* 4.2BSD inode format */ 277 #define FS_44INODEFMT 2 /* 4.4BSD inode format */ 278 279 /* 280 * File system clean flags 281 */ 282 #define FS_ISCLEAN 0x01 283 #define FS_WASCLEAN 0x02 284 285 /* 286 * Preference for optimization. 287 */ 288 #define FS_OPTTIME 0 /* minimize allocation time */ 289 #define FS_OPTSPACE 1 /* minimize disk fragmentation */ 290 291 /* 292 * File system flags 293 */ 294 #define FS_UNCLEAN 0x01 /* file system not clean at mount (unused) */ 295 #define FS_DOSOFTDEP 0x02 /* file system using soft dependencies */ 296 297 /* 298 * File system internal flags, also in fs_flags. 299 * (Pick highest number to avoid conflicts with others) 300 */ 301 #define FS_SWAPPED 0x80 /* file system is endian swapped */ 302 #define FS_INTERNAL 0x80 /* mask for internal flags */ 303 304 /* 305 * Rotational layout table format types 306 */ 307 #define FS_42POSTBLFMT -1 /* 4.2BSD rotational table format */ 308 #define FS_DYNAMICPOSTBLFMT 1 /* dynamic rotational table format */ 309 /* 310 * Macros for access to superblock array structures 311 */ 312 #define fs_postbl(fs, cylno) \ 313 (((fs)->fs_postblformat == FS_42POSTBLFMT) \ 314 ? ((fs)->fs_opostbl[cylno]) \ 315 : ((int16_t *)((u_int8_t *)(fs) + \ 316 (fs)->fs_postbloff) + (cylno) * (fs)->fs_nrpos)) 317 #define fs_rotbl(fs) \ 318 (((fs)->fs_postblformat == FS_42POSTBLFMT) \ 319 ? ((fs)->fs_space) \ 320 : ((u_int8_t *)((u_int8_t *)(fs) + (fs)->fs_rotbloff))) 321 322 /* 323 * The size of a cylinder group is calculated by CGSIZE. The maximum size 324 * is limited by the fact that cylinder groups are at most one block. 325 * Its size is derived from the size of the maps maintained in the 326 * cylinder group and the (struct cg) size. 327 */ 328 #define CGSIZE(fs) \ 329 /* base cg */ (sizeof(struct cg) + sizeof(int32_t) + \ 330 /* blktot size */ (fs)->fs_cpg * sizeof(int32_t) + \ 331 /* blks size */ (fs)->fs_cpg * (fs)->fs_nrpos * sizeof(int16_t) + \ 332 /* inode map */ howmany((fs)->fs_ipg, NBBY) + \ 333 /* block map */ howmany((fs)->fs_cpg * (fs)->fs_spc / NSPF(fs), NBBY) +\ 334 /* if present */ ((fs)->fs_contigsumsize <= 0 ? 0 : \ 335 /* cluster sum */ (fs)->fs_contigsumsize * sizeof(int32_t) + \ 336 /* cluster map */ howmany((fs)->fs_cpg * (fs)->fs_spc / NSPB(fs), NBBY))) 337 338 /* 339 * Convert cylinder group to base address of its global summary info. 340 */ 341 #define fs_cs(fs, indx) fs_csp[indx] 342 343 /* 344 * Cylinder group block for a file system. 345 */ 346 #define CG_MAGIC 0x090255 347 struct cg { 348 int32_t cg_firstfield; /* historic cyl groups linked list */ 349 int32_t cg_magic; /* magic number */ 350 int32_t cg_time; /* time last written */ 351 int32_t cg_cgx; /* we are the cgx'th cylinder group */ 352 int16_t cg_ncyl; /* number of cyl's this cg */ 353 int16_t cg_niblk; /* number of inode blocks this cg */ 354 int32_t cg_ndblk; /* number of data blocks this cg */ 355 struct csum cg_cs; /* cylinder summary information */ 356 int32_t cg_rotor; /* position of last used block */ 357 int32_t cg_frotor; /* position of last used frag */ 358 int32_t cg_irotor; /* position of last used inode */ 359 int32_t cg_frsum[MAXFRAG]; /* counts of available frags */ 360 int32_t cg_btotoff; /* (int32) block totals per cylinder */ 361 int32_t cg_boff; /* (u_int16) free block positions */ 362 int32_t cg_iusedoff; /* (u_int8) used inode map */ 363 int32_t cg_freeoff; /* (u_int8) free block map */ 364 int32_t cg_nextfreeoff; /* (u_int8) next available space */ 365 int32_t cg_clustersumoff; /* (u_int32) counts of avail clusters */ 366 int32_t cg_clusteroff; /* (u_int8) free cluster map */ 367 int32_t cg_nclusterblks; /* number of clusters this cg */ 368 int32_t cg_sparecon[13]; /* reserved for future use */ 369 u_int8_t cg_space[1]; /* space for cylinder group maps */ 370 /* actually longer */ 371 }; 372 373 /* 374 * Macros for access to cylinder group array structures 375 */ 376 #define cg_blktot(cgp, ns) \ 377 ((ufs_rw32((cgp)->cg_magic, (ns)) != CG_MAGIC) \ 378 ? (((struct ocg *)(cgp))->cg_btot) \ 379 : ((int32_t *)((u_int8_t *)(cgp) + \ 380 ufs_rw32((cgp)->cg_btotoff, (ns))))) 381 #define cg_blks(fs, cgp, cylno, ns) \ 382 ((ufs_rw32((cgp)->cg_magic, ns) != CG_MAGIC) \ 383 ? (((struct ocg *)(cgp))->cg_b[cylno]) \ 384 : ((int16_t *)((u_int8_t *)(cgp) + \ 385 ufs_rw32((cgp)->cg_boff, (ns))) + \ 386 (cylno) * (fs)->fs_nrpos)) 387 #define cg_inosused(cgp, ns) \ 388 ((ufs_rw32((cgp)->cg_magic, (ns)) != CG_MAGIC) \ 389 ? (((struct ocg *)(cgp))->cg_iused) \ 390 : ((u_int8_t *)((u_int8_t *)(cgp) + \ 391 ufs_rw32((cgp)->cg_iusedoff, (ns))))) 392 #define cg_blksfree(cgp, ns) \ 393 ((ufs_rw32((cgp)->cg_magic, (ns)) != CG_MAGIC) \ 394 ? (((struct ocg *)(cgp))->cg_free) \ 395 : ((u_int8_t *)((u_int8_t *)(cgp) + \ 396 ufs_rw32((cgp)->cg_freeoff, (ns))))) 397 #define cg_chkmagic(cgp, ns) \ 398 (ufs_rw32((cgp)->cg_magic, (ns)) == CG_MAGIC || \ 399 ufs_rw32(((struct ocg *)(cgp))->cg_magic, (ns)) == \ 400 CG_MAGIC) 401 #define cg_clustersfree(cgp, ns) \ 402 ((u_int8_t *)((u_int8_t *)(cgp) + \ 403 ufs_rw32((cgp)->cg_clusteroff, (ns)))) 404 #define cg_clustersum(cgp, ns) \ 405 ((int32_t *)((u_int8_t *)(cgp) + \ 406 ufs_rw32((cgp)->cg_clustersumoff, (ns)))) 407 408 /* 409 * The following structure is defined 410 * for compatibility with old file systems. 411 */ 412 struct ocg { 413 int32_t cg_firstfield; /* historic linked list of cyl groups */ 414 int32_t cg_unused_1; /* used for incore cyl groups */ 415 int32_t cg_time; /* time last written */ 416 int32_t cg_cgx; /* we are the cgx'th cylinder group */ 417 int16_t cg_ncyl; /* number of cyl's this cg */ 418 int16_t cg_niblk; /* number of inode blocks this cg */ 419 int32_t cg_ndblk; /* number of data blocks this cg */ 420 struct csum cg_cs; /* cylinder summary information */ 421 int32_t cg_rotor; /* position of last used block */ 422 int32_t cg_frotor; /* position of last used frag */ 423 int32_t cg_irotor; /* position of last used inode */ 424 int32_t cg_frsum[8]; /* counts of available frags */ 425 int32_t cg_btot[32]; /* block totals per cylinder */ 426 int16_t cg_b[32][8]; /* positions of free blocks */ 427 u_int8_t cg_iused[256]; /* used inode map */ 428 int32_t cg_magic; /* magic number */ 429 u_int8_t cg_free[1]; /* free block map */ 430 /* actually longer */ 431 }; 432 433 /* 434 * Turn file system block numbers into disk block addresses. 435 * This maps file system blocks to device size blocks. 436 */ 437 #define fsbtodb(fs, b) ((b) << (fs)->fs_fsbtodb) 438 #define dbtofsb(fs, b) ((b) >> (fs)->fs_fsbtodb) 439 440 /* 441 * Cylinder group macros to locate things in cylinder groups. 442 * They calc file system addresses of cylinder group data structures. 443 */ 444 #define cgbase(fs, c) ((ufs_daddr_t)((fs)->fs_fpg * (c))) 445 #define cgdmin(fs, c) (cgstart(fs, c) + (fs)->fs_dblkno) /* 1st data */ 446 #define cgimin(fs, c) (cgstart(fs, c) + (fs)->fs_iblkno) /* inode blk */ 447 #define cgsblock(fs, c) (cgstart(fs, c) + (fs)->fs_sblkno) /* super blk */ 448 #define cgtod(fs, c) (cgstart(fs, c) + (fs)->fs_cblkno) /* cg block */ 449 #define cgstart(fs, c) \ 450 (cgbase(fs, c) + (fs)->fs_cgoffset * ((c) & ~((fs)->fs_cgmask))) 451 452 /* 453 * Macros for handling inode numbers: 454 * inode number to file system block offset. 455 * inode number to cylinder group number. 456 * inode number to file system block address. 457 */ 458 #define ino_to_cg(fs, x) ((x) / (fs)->fs_ipg) 459 #define ino_to_fsba(fs, x) \ 460 ((ufs_daddr_t)(cgimin(fs, ino_to_cg(fs, x)) + \ 461 (blkstofrags((fs), (((x) % (fs)->fs_ipg) / INOPB(fs)))))) 462 #define ino_to_fsbo(fs, x) ((x) % INOPB(fs)) 463 464 /* 465 * Give cylinder group number for a file system block. 466 * Give cylinder group block number for a file system block. 467 */ 468 #define dtog(fs, d) ((d) / (fs)->fs_fpg) 469 #define dtogd(fs, d) ((d) % (fs)->fs_fpg) 470 471 /* 472 * Extract the bits for a block from a map. 473 * Compute the cylinder and rotational position of a cyl block addr. 474 */ 475 #define blkmap(fs, map, loc) \ 476 (((map)[(loc) / NBBY] >> ((loc) % NBBY)) & (0xff >> (NBBY - (fs)->fs_frag))) 477 #define cbtocylno(fs, bno) \ 478 ((bno) * NSPF(fs) / (fs)->fs_spc) 479 #define cbtorpos(fs, bno) \ 480 (((bno) * NSPF(fs) % (fs)->fs_spc / (fs)->fs_nsect * (fs)->fs_trackskew + \ 481 (bno) * NSPF(fs) % (fs)->fs_spc % (fs)->fs_nsect * (fs)->fs_interleave) % \ 482 (fs)->fs_nsect * (fs)->fs_nrpos / (fs)->fs_npsect) 483 484 /* 485 * The following macros optimize certain frequently calculated 486 * quantities by using shifts and masks in place of divisions 487 * modulos and multiplications. 488 */ 489 #define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \ 490 ((loc) & (fs)->fs_qbmask) 491 #define fragoff(fs, loc) /* calculates (loc % fs->fs_fsize) */ \ 492 ((loc) & (fs)->fs_qfmask) 493 #define lblktosize(fs, blk) /* calculates ((off_t)blk * fs->fs_bsize) */ \ 494 ((off_t)(blk) << (fs)->fs_bshift) 495 #define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \ 496 ((loc) >> (fs)->fs_bshift) 497 #define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \ 498 ((loc) >> (fs)->fs_fshift) 499 #define blkroundup(fs, size) /* calculates roundup(size, fs->fs_bsize) */ \ 500 (((size) + (fs)->fs_qbmask) & (fs)->fs_bmask) 501 #define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \ 502 (((size) + (fs)->fs_qfmask) & (fs)->fs_fmask) 503 #define fragstoblks(fs, frags) /* calculates (frags / fs->fs_frag) */ \ 504 ((frags) >> (fs)->fs_fragshift) 505 #define blkstofrags(fs, blks) /* calculates (blks * fs->fs_frag) */ \ 506 ((blks) << (fs)->fs_fragshift) 507 #define fragnum(fs, fsb) /* calculates (fsb % fs->fs_frag) */ \ 508 ((fsb) & ((fs)->fs_frag - 1)) 509 #define blknum(fs, fsb) /* calculates rounddown(fsb, fs->fs_frag) */ \ 510 ((fsb) &~ ((fs)->fs_frag - 1)) 511 512 /* 513 * Determine the number of available frags given a 514 * percentage to hold in reserve. 515 */ 516 #define freespace(fs, percentreserved) \ 517 (blkstofrags((fs), (fs)->fs_cstotal.cs_nbfree) + \ 518 (fs)->fs_cstotal.cs_nffree - \ 519 ((off_t)((fs)->fs_dsize) * (percentreserved) / 100)) 520 521 /* 522 * Determining the size of a file block in the file system. 523 */ 524 #define blksize(fs, ip, lbn) \ 525 (((lbn) >= NDADDR || (ip)->i_ffs_size >= lblktosize(fs, (lbn) + 1)) \ 526 ? (fs)->fs_bsize \ 527 : (fragroundup(fs, blkoff(fs, (ip)->i_ffs_size)))) 528 #define dblksize(fs, dip, lbn) \ 529 (((lbn) >= NDADDR || (dip)->di_size >= lblktosize(fs, (lbn) + 1)) \ 530 ? (fs)->fs_bsize \ 531 : (fragroundup(fs, blkoff(fs, (dip)->di_size)))) 532 533 /* 534 * Number of disk sectors per block/fragment; assumes DEV_BSIZE byte 535 * sector size. 536 */ 537 #define NSPB(fs) ((fs)->fs_nspf << (fs)->fs_fragshift) 538 #define NSPF(fs) ((fs)->fs_nspf) 539 540 /* 541 * Number of inodes in a secondary storage block/fragment. 542 */ 543 #define INOPB(fs) ((fs)->fs_inopb) 544 #define INOPF(fs) ((fs)->fs_inopb >> (fs)->fs_fragshift) 545 546 /* 547 * Number of indirects in a file system block. 548 */ 549 #define NINDIR(fs) ((fs)->fs_nindir) 550 551 #endif /* !_UFS_FFS_FS_H_ */ 552
Indexes created Thu Oct 02 14:10:14 GMT 2025