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1.1 ! root 1: /* ! 2: * Copyright (c) 1982, 1986 Regents of the University of California. ! 3: * All rights reserved. ! 4: * ! 5: * Redistribution is only permitted until one year after the first shipment ! 6: * of 4.4BSD by the Regents. Otherwise, redistribution and use in source and ! 7: * binary forms are permitted provided that: (1) source distributions retain ! 8: * this entire copyright notice and comment, and (2) distributions including ! 9: * binaries display the following acknowledgement: This product includes ! 10: * software developed by the University of California, Berkeley and its ! 11: * contributors'' in the documentation or other materials provided with the ! 12: * distribution and in all advertising materials mentioning features or use ! 13: * of this software. Neither the name of the University nor the names of ! 14: * its contributors may be used to endorse or promote products derived from ! 15: * this software without specific prior written permission. ! 16: * THIS SOFTWARE IS PROVIDED AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED ! 17: * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF ! 18: * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. ! 19: * ! 20: * @(#)fs.h 7.10 (Berkeley) 6/28/90 ! 21: */ ! 22: ! 23: /* ! 24: * Each disk drive contains some number of file systems. ! 25: * A file system consists of a number of cylinder groups. ! 26: * Each cylinder group has inodes and data. ! 27: * ! 28: * A file system is described by its super-block, which in turn ! 29: * describes the cylinder groups. The super-block is critical ! 30: * data and is replicated in each cylinder group to protect against ! 31: * catastrophic loss. This is done at `newfs' time and the critical ! 32: * super-block data does not change, so the copies need not be ! 33: * referenced further unless disaster strikes. ! 34: * ! 35: * For file system fs, the offsets of the various blocks of interest ! 36: * are given in the super block as: ! 37: * [fs->fs_sblkno] Super-block ! 38: * [fs->fs_cblkno] Cylinder group block ! 39: * [fs->fs_iblkno] Inode blocks ! 40: * [fs->fs_dblkno] Data blocks ! 41: * The beginning of cylinder group cg in fs, is given by ! 42: * the ``cgbase(fs, cg)'' macro. ! 43: * ! 44: * The first boot and super blocks are given in absolute disk addresses. ! 45: * The byte-offset forms are preferred, as they don't imply a sector size. ! 46: */ ! 47: #define BBSIZE 8192 ! 48: #define SBSIZE 8192 ! 49: #define BBOFF ((off_t)(0)) ! 50: #define SBOFF ((off_t)(BBOFF + BBSIZE)) ! 51: #define BBLOCK ((daddr_t)(0)) ! 52: #define SBLOCK ((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE)) ! 53: ! 54: /* ! 55: * Addresses stored in inodes are capable of addressing fragments ! 56: * of `blocks'. File system blocks of at most size MAXBSIZE can ! 57: * be optionally broken into 2, 4, or 8 pieces, each of which is ! 58: * addressible; these pieces may be DEV_BSIZE, or some multiple of ! 59: * a DEV_BSIZE unit. ! 60: * ! 61: * Large files consist of exclusively large data blocks. To avoid ! 62: * undue wasted disk space, the last data block of a small file may be ! 63: * allocated as only as many fragments of a large block as are ! 64: * necessary. The file system format retains only a single pointer ! 65: * to such a fragment, which is a piece of a single large block that ! 66: * has been divided. The size of such a fragment is determinable from ! 67: * information in the inode, using the ``blksize(fs, ip, lbn)'' macro. ! 68: * ! 69: * The file system records space availability at the fragment level; ! 70: * to determine block availability, aligned fragments are examined. ! 71: * ! 72: * The root inode is the root of the file system. ! 73: * Inode 0 can't be used for normal purposes and ! 74: * historically bad blocks were linked to inode 1, ! 75: * thus the root inode is 2. (inode 1 is no longer used for ! 76: * this purpose, however numerous dump tapes make this ! 77: * assumption, so we are stuck with it) ! 78: */ ! 79: #define ROOTINO ((ino_t)2) /* i number of all roots */ ! 80: ! 81: /* ! 82: * MINBSIZE is the smallest allowable block size. ! 83: * In order to insure that it is possible to create files of size ! 84: * 2^32 with only two levels of indirection, MINBSIZE is set to 4096. ! 85: * MINBSIZE must be big enough to hold a cylinder group block, ! 86: * thus changes to (struct cg) must keep its size within MINBSIZE. ! 87: * Note that super blocks are always of size SBSIZE, ! 88: * and that both SBSIZE and MAXBSIZE must be >= MINBSIZE. ! 89: */ ! 90: #define MINBSIZE 4096 ! 91: ! 92: /* ! 93: * The path name on which the file system is mounted is maintained ! 94: * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in ! 95: * the super block for this name. ! 96: * The limit on the amount of summary information per file system ! 97: * is defined by MAXCSBUFS. It is currently parameterized for a ! 98: * maximum of two million cylinders. ! 99: */ ! 100: #define MAXMNTLEN 512 ! 101: #define MAXCSBUFS 32 ! 102: ! 103: /* ! 104: * Per cylinder group information; summarized in blocks allocated ! 105: * from first cylinder group data blocks. These blocks have to be ! 106: * read in from fs_csaddr (size fs_cssize) in addition to the ! 107: * super block. ! 108: * ! 109: * N.B. sizeof(struct csum) must be a power of two in order for ! 110: * the ``fs_cs'' macro to work (see below). ! 111: */ ! 112: struct csum { ! 113: long cs_ndir; /* number of directories */ ! 114: long cs_nbfree; /* number of free blocks */ ! 115: long cs_nifree; /* number of free inodes */ ! 116: long cs_nffree; /* number of free frags */ ! 117: }; ! 118: ! 119: /* ! 120: * Super block for a file system. ! 121: */ ! 122: #define FS_MAGIC 0x011954 ! 123: #define FSOKAY 0x7c269d38 ! 124: struct fs ! 125: { ! 126: struct fs *fs_link; /* linked list of file systems */ ! 127: struct fs *fs_rlink; /* used for incore super blocks */ ! 128: daddr_t fs_sblkno; /* addr of super-block in filesys */ ! 129: daddr_t fs_cblkno; /* offset of cyl-block in filesys */ ! 130: daddr_t fs_iblkno; /* offset of inode-blocks in filesys */ ! 131: daddr_t fs_dblkno; /* offset of first data after cg */ ! 132: long fs_cgoffset; /* cylinder group offset in cylinder */ ! 133: long fs_cgmask; /* used to calc mod fs_ntrak */ ! 134: time_t fs_time; /* last time written */ ! 135: long fs_size; /* number of blocks in fs */ ! 136: long fs_dsize; /* number of data blocks in fs */ ! 137: long fs_ncg; /* number of cylinder groups */ ! 138: long fs_bsize; /* size of basic blocks in fs */ ! 139: long fs_fsize; /* size of frag blocks in fs */ ! 140: long fs_frag; /* number of frags in a block in fs */ ! 141: /* these are configuration parameters */ ! 142: long fs_minfree; /* minimum percentage of free blocks */ ! 143: long fs_rotdelay; /* num of ms for optimal next block */ ! 144: long fs_rps; /* disk revolutions per second */ ! 145: /* these fields can be computed from the others */ ! 146: long fs_bmask; /* ``blkoff'' calc of blk offsets */ ! 147: long fs_fmask; /* ``fragoff'' calc of frag offsets */ ! 148: long fs_bshift; /* ``lblkno'' calc of logical blkno */ ! 149: long fs_fshift; /* ``numfrags'' calc number of frags */ ! 150: /* these are configuration parameters */ ! 151: long fs_maxcontig; /* max number of contiguous blks */ ! 152: long fs_maxbpg; /* max number of blks per cyl group */ ! 153: /* these fields can be computed from the others */ ! 154: long fs_fragshift; /* block to frag shift */ ! 155: long fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */ ! 156: long fs_sbsize; /* actual size of super block */ ! 157: long fs_csmask; /* csum block offset */ ! 158: long fs_csshift; /* csum block number */ ! 159: long fs_nindir; /* value of NINDIR */ ! 160: long fs_inopb; /* value of INOPB */ ! 161: long fs_nspf; /* value of NSPF */ ! 162: /* yet another configuration parameter */ ! 163: long fs_optim; /* optimization preference, see below */ ! 164: /* these fields are derived from the hardware */ ! 165: long fs_npsect; /* # sectors/track including spares */ ! 166: long fs_interleave; /* hardware sector interleave */ ! 167: long fs_trackskew; /* sector 0 skew, per track */ ! 168: long fs_headswitch; /* head switch time, usec */ ! 169: long fs_trkseek; /* track-to-track seek, usec */ ! 170: /* sizes determined by number of cylinder groups and their sizes */ ! 171: daddr_t fs_csaddr; /* blk addr of cyl grp summary area */ ! 172: long fs_cssize; /* size of cyl grp summary area */ ! 173: long fs_cgsize; /* cylinder group size */ ! 174: /* these fields are derived from the hardware */ ! 175: long fs_ntrak; /* tracks per cylinder */ ! 176: long fs_nsect; /* sectors per track */ ! 177: long fs_spc; /* sectors per cylinder */ ! 178: /* this comes from the disk driver partitioning */ ! 179: long fs_ncyl; /* cylinders in file system */ ! 180: /* these fields can be computed from the others */ ! 181: long fs_cpg; /* cylinders per group */ ! 182: long fs_ipg; /* inodes per group */ ! 183: long fs_fpg; /* blocks per group * fs_frag */ ! 184: /* this data must be re-computed after crashes */ ! 185: struct csum fs_cstotal; /* cylinder summary information */ ! 186: /* these fields are cleared at mount time */ ! 187: char fs_fmod; /* super block modified flag */ ! 188: char fs_clean; /* file system is clean flag */ ! 189: char fs_ronly; /* mounted read-only flag */ ! 190: char fs_flags; /* currently unused flag */ ! 191: char fs_fsmnt[MAXMNTLEN]; /* name mounted on */ ! 192: /* these fields retain the current block allocation info */ ! 193: long fs_cgrotor; /* last cg searched */ ! 194: struct csum *fs_csp[MAXCSBUFS];/* list of fs_cs info buffers */ ! 195: long fs_cpc; /* cyl per cycle in postbl */ ! 196: short fs_opostbl[16][8]; /* old rotation block list head */ ! 197: long fs_sparecon[55]; /* reserved for future constants */ ! 198: long fs_state; /* validate fs_clean field */ ! 199: quad fs_qbmask; /* ~fs_bmask - for use with quad size */ ! 200: quad fs_qfmask; /* ~fs_fmask - for use with quad size */ ! 201: long fs_postblformat; /* format of positional layout tables */ ! 202: long fs_nrpos; /* number of rotaional positions */ ! 203: long fs_postbloff; /* (short) rotation block list head */ ! 204: long fs_rotbloff; /* (u_char) blocks for each rotation */ ! 205: long fs_magic; /* magic number */ ! 206: u_char fs_space[1]; /* list of blocks for each rotation */ ! 207: /* actually longer */ ! 208: }; ! 209: /* ! 210: * Preference for optimization. ! 211: */ ! 212: #define FS_OPTTIME 0 /* minimize allocation time */ ! 213: #define FS_OPTSPACE 1 /* minimize disk fragmentation */ ! 214: ! 215: /* ! 216: * Rotational layout table format types ! 217: */ ! 218: #define FS_42POSTBLFMT -1 /* 4.2BSD rotational table format */ ! 219: #define FS_DYNAMICPOSTBLFMT 1 /* dynamic rotational table format */ ! 220: /* ! 221: * Macros for access to superblock array structures ! 222: */ ! 223: #define fs_postbl(fs, cylno) \ ! 224: (((fs)->fs_postblformat == FS_42POSTBLFMT) \ ! 225: ? ((fs)->fs_opostbl[cylno]) \ ! 226: : ((short *)((char *)(fs) + (fs)->fs_postbloff) + (cylno) * (fs)->fs_nrpos)) ! 227: #define fs_rotbl(fs) \ ! 228: (((fs)->fs_postblformat == FS_42POSTBLFMT) \ ! 229: ? ((fs)->fs_space) \ ! 230: : ((u_char *)((char *)(fs) + (fs)->fs_rotbloff))) ! 231: ! 232: /* ! 233: * Convert cylinder group to base address of its global summary info. ! 234: * ! 235: * N.B. This macro assumes that sizeof(struct csum) is a power of two. ! 236: */ ! 237: #define fs_cs(fs, indx) \ ! 238: fs_csp[(indx) >> (fs)->fs_csshift][(indx) & ~(fs)->fs_csmask] ! 239: ! 240: /* ! 241: * Cylinder group block for a file system. ! 242: */ ! 243: #define CG_MAGIC 0x090255 ! 244: struct cg { ! 245: struct cg *cg_link; /* linked list of cyl groups */ ! 246: long cg_magic; /* magic number */ ! 247: time_t cg_time; /* time last written */ ! 248: long cg_cgx; /* we are the cgx'th cylinder group */ ! 249: short cg_ncyl; /* number of cyl's this cg */ ! 250: short cg_niblk; /* number of inode blocks this cg */ ! 251: long cg_ndblk; /* number of data blocks this cg */ ! 252: struct csum cg_cs; /* cylinder summary information */ ! 253: long cg_rotor; /* position of last used block */ ! 254: long cg_frotor; /* position of last used frag */ ! 255: long cg_irotor; /* position of last used inode */ ! 256: long cg_frsum[MAXFRAG]; /* counts of available frags */ ! 257: long cg_btotoff; /* (long) block totals per cylinder */ ! 258: long cg_boff; /* (short) free block positions */ ! 259: long cg_iusedoff; /* (char) used inode map */ ! 260: long cg_freeoff; /* (u_char) free block map */ ! 261: long cg_nextfreeoff; /* (u_char) next available space */ ! 262: long cg_sparecon[16]; /* reserved for future use */ ! 263: u_char cg_space[1]; /* space for cylinder group maps */ ! 264: /* actually longer */ ! 265: }; ! 266: /* ! 267: * Macros for access to cylinder group array structures ! 268: */ ! 269: #define cg_blktot(cgp) \ ! 270: (((cgp)->cg_magic != CG_MAGIC) \ ! 271: ? (((struct ocg *)(cgp))->cg_btot) \ ! 272: : ((long *)((char *)(cgp) + (cgp)->cg_btotoff))) ! 273: #define cg_blks(fs, cgp, cylno) \ ! 274: (((cgp)->cg_magic != CG_MAGIC) \ ! 275: ? (((struct ocg *)(cgp))->cg_b[cylno]) \ ! 276: : ((short *)((char *)(cgp) + (cgp)->cg_boff) + (cylno) * (fs)->fs_nrpos)) ! 277: #define cg_inosused(cgp) \ ! 278: (((cgp)->cg_magic != CG_MAGIC) \ ! 279: ? (((struct ocg *)(cgp))->cg_iused) \ ! 280: : ((char *)((char *)(cgp) + (cgp)->cg_iusedoff))) ! 281: #define cg_blksfree(cgp) \ ! 282: (((cgp)->cg_magic != CG_MAGIC) \ ! 283: ? (((struct ocg *)(cgp))->cg_free) \ ! 284: : ((u_char *)((char *)(cgp) + (cgp)->cg_freeoff))) ! 285: #define cg_chkmagic(cgp) \ ! 286: ((cgp)->cg_magic == CG_MAGIC || ((struct ocg *)(cgp))->cg_magic == CG_MAGIC) ! 287: ! 288: /* ! 289: * The following structure is defined ! 290: * for compatibility with old file systems. ! 291: */ ! 292: struct ocg { ! 293: struct ocg *cg_link; /* linked list of cyl groups */ ! 294: struct ocg *cg_rlink; /* used for incore cyl groups */ ! 295: time_t cg_time; /* time last written */ ! 296: long cg_cgx; /* we are the cgx'th cylinder group */ ! 297: short cg_ncyl; /* number of cyl's this cg */ ! 298: short cg_niblk; /* number of inode blocks this cg */ ! 299: long cg_ndblk; /* number of data blocks this cg */ ! 300: struct csum cg_cs; /* cylinder summary information */ ! 301: long cg_rotor; /* position of last used block */ ! 302: long cg_frotor; /* position of last used frag */ ! 303: long cg_irotor; /* position of last used inode */ ! 304: long cg_frsum[8]; /* counts of available frags */ ! 305: long cg_btot[32]; /* block totals per cylinder */ ! 306: short cg_b[32][8]; /* positions of free blocks */ ! 307: char cg_iused[256]; /* used inode map */ ! 308: long cg_magic; /* magic number */ ! 309: u_char cg_free[1]; /* free block map */ ! 310: /* actually longer */ ! 311: }; ! 312: ! 313: /* ! 314: * Turn file system block numbers into disk block addresses. ! 315: * This maps file system blocks to device size blocks. ! 316: */ ! 317: #define fsbtodb(fs, b) ((b) << (fs)->fs_fsbtodb) ! 318: #define dbtofsb(fs, b) ((b) >> (fs)->fs_fsbtodb) ! 319: ! 320: /* ! 321: * Cylinder group macros to locate things in cylinder groups. ! 322: * They calc file system addresses of cylinder group data structures. ! 323: */ ! 324: #define cgbase(fs, c) ((daddr_t)((fs)->fs_fpg * (c))) ! 325: #define cgstart(fs, c) \ ! 326: (cgbase(fs, c) + (fs)->fs_cgoffset * ((c) & ~((fs)->fs_cgmask))) ! 327: #define cgsblock(fs, c) (cgstart(fs, c) + (fs)->fs_sblkno) /* super blk */ ! 328: #define cgtod(fs, c) (cgstart(fs, c) + (fs)->fs_cblkno) /* cg block */ ! 329: #define cgimin(fs, c) (cgstart(fs, c) + (fs)->fs_iblkno) /* inode blk */ ! 330: #define cgdmin(fs, c) (cgstart(fs, c) + (fs)->fs_dblkno) /* 1st data */ ! 331: ! 332: /* ! 333: * Macros for handling inode numbers: ! 334: * inode number to file system block offset. ! 335: * inode number to cylinder group number. ! 336: * inode number to file system block address. ! 337: */ ! 338: #define itoo(fs, x) ((x) % INOPB(fs)) ! 339: #define itog(fs, x) ((x) / (fs)->fs_ipg) ! 340: #define itod(fs, x) \ ! 341: ((daddr_t)(cgimin(fs, itog(fs, x)) + \ ! 342: (blkstofrags((fs), (((x) % (fs)->fs_ipg) / INOPB(fs)))))) ! 343: ! 344: /* ! 345: * Give cylinder group number for a file system block. ! 346: * Give cylinder group block number for a file system block. ! 347: */ ! 348: #define dtog(fs, d) ((d) / (fs)->fs_fpg) ! 349: #define dtogd(fs, d) ((d) % (fs)->fs_fpg) ! 350: ! 351: /* ! 352: * Extract the bits for a block from a map. ! 353: * Compute the cylinder and rotational position of a cyl block addr. ! 354: */ ! 355: #define blkmap(fs, map, loc) \ ! 356: (((map)[(loc) / NBBY] >> ((loc) % NBBY)) & (0xff >> (NBBY - (fs)->fs_frag))) ! 357: #define cbtocylno(fs, bno) \ ! 358: ((bno) * NSPF(fs) / (fs)->fs_spc) ! 359: #define cbtorpos(fs, bno) \ ! 360: (((bno) * NSPF(fs) % (fs)->fs_spc / (fs)->fs_nsect * (fs)->fs_trackskew + \ ! 361: (bno) * NSPF(fs) % (fs)->fs_spc % (fs)->fs_nsect * (fs)->fs_interleave) % \ ! 362: (fs)->fs_nsect * (fs)->fs_nrpos / (fs)->fs_npsect) ! 363: ! 364: /* ! 365: * The following macros optimize certain frequently calculated ! 366: * quantities by using shifts and masks in place of divisions ! 367: * modulos and multiplications. ! 368: */ ! 369: #define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \ ! 370: ((loc) & ~(fs)->fs_bmask) ! 371: #define fragoff(fs, loc) /* calculates (loc % fs->fs_fsize) */ \ ! 372: ((loc) & ~(fs)->fs_fmask) ! 373: #define lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \ ! 374: ((blk) << (fs)->fs_bshift) ! 375: #define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \ ! 376: ((loc) >> (fs)->fs_bshift) ! 377: #define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \ ! 378: ((loc) >> (fs)->fs_fshift) ! 379: #define blkroundup(fs, size) /* calculates roundup(size, fs->fs_bsize) */ \ ! 380: (((size) + (fs)->fs_bsize - 1) & (fs)->fs_bmask) ! 381: #define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \ ! 382: (((size) + (fs)->fs_fsize - 1) & (fs)->fs_fmask) ! 383: #define fragstoblks(fs, frags) /* calculates (frags / fs->fs_frag) */ \ ! 384: ((frags) >> (fs)->fs_fragshift) ! 385: #define blkstofrags(fs, blks) /* calculates (blks * fs->fs_frag) */ \ ! 386: ((blks) << (fs)->fs_fragshift) ! 387: #define fragnum(fs, fsb) /* calculates (fsb % fs->fs_frag) */ \ ! 388: ((fsb) & ((fs)->fs_frag - 1)) ! 389: #define blknum(fs, fsb) /* calculates rounddown(fsb, fs->fs_frag) */ \ ! 390: ((fsb) &~ ((fs)->fs_frag - 1)) ! 391: ! 392: /* ! 393: * Determine the number of available frags given a ! 394: * percentage to hold in reserve ! 395: */ ! 396: #define freespace(fs, percentreserved) \ ! 397: (blkstofrags((fs), (fs)->fs_cstotal.cs_nbfree) + \ ! 398: (fs)->fs_cstotal.cs_nffree - ((fs)->fs_dsize * (percentreserved) / 100)) ! 399: ! 400: /* ! 401: * Determining the size of a file block in the file system. ! 402: */ ! 403: #define blksize(fs, ip, lbn) \ ! 404: (((lbn) >= NDADDR || (ip)->i_size >= ((lbn) + 1) << (fs)->fs_bshift) \ ! 405: ? (fs)->fs_bsize \ ! 406: : (fragroundup(fs, blkoff(fs, (ip)->i_size)))) ! 407: #define dblksize(fs, dip, lbn) \ ! 408: (((lbn) >= NDADDR || (dip)->di_size >= ((lbn) + 1) << (fs)->fs_bshift) \ ! 409: ? (fs)->fs_bsize \ ! 410: : (fragroundup(fs, blkoff(fs, (dip)->di_size)))) ! 411: ! 412: /* ! 413: * Number of disk sectors per block; assumes DEV_BSIZE byte sector size. ! 414: */ ! 415: #define NSPB(fs) ((fs)->fs_nspf << (fs)->fs_fragshift) ! 416: #define NSPF(fs) ((fs)->fs_nspf) ! 417: ! 418: /* ! 419: * INOPB is the number of inodes in a secondary storage block. ! 420: */ ! 421: #define INOPB(fs) ((fs)->fs_inopb) ! 422: #define INOPF(fs) ((fs)->fs_inopb >> (fs)->fs_fragshift) ! 423: ! 424: /* ! 425: * NINDIR is the number of indirects in a file system block. ! 426: */ ! 427: #define NINDIR(fs) ((fs)->fs_nindir) ! 428: ! 429: #ifdef KERNEL ! 430: struct fs *getfs(); ! 431: #endif
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