--- /dev/null
+/*
+ * Mach Operating System
+ * Copyright (c) 1991,1990 Carnegie Mellon University
+ * All Rights Reserved.
+ *
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ *
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
+ * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * Carnegie Mellon requests users of this software to return to
+ *
+ * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
+ * School of Computer Science
+ * Carnegie Mellon University
+ * Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie Mellon
+ * the rights to redistribute these changes.
+ */
+/*
+ * Copyright (c) 1982, 1986 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the University of California, Berkeley. The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * @(#)fs.h 7.7 (Berkeley) 5/9/89
+ */
+
+/*
+ * Each disk drive contains some number of file systems.
+ * A file system consists of a number of cylinder groups.
+ * Each cylinder group has inodes and data.
+ *
+ * A file system is described by its super-block, which in turn
+ * describes the cylinder groups. The super-block is critical
+ * data and is replicated in each cylinder group to protect against
+ * catastrophic loss. This is done at `newfs' time and the critical
+ * super-block data does not change, so the copies need not be
+ * referenced further unless disaster strikes.
+ *
+ * For file system fs, the offsets of the various blocks of interest
+ * are given in the super block as:
+ * [fs->fs_sblkno] Super-block
+ * [fs->fs_cblkno] Cylinder group block
+ * [fs->fs_iblkno] Inode blocks
+ * [fs->fs_dblkno] Data blocks
+ * The beginning of cylinder group cg in fs, is given by
+ * the ``cgbase(fs, cg)'' macro.
+ *
+ * The first boot and super blocks are given in absolute disk addresses.
+ * The byte-offset forms are preferred, as they don't imply a sector size.
+ */
+#define BBSIZE 8192
+#define SBSIZE 8192
+#define BBOFF ((mach_off_t)(0))
+#define SBOFF ((mach_off_t)(BBOFF + BBSIZE))
+#define BBLOCK ((mach_daddr_t)(0))
+#define SBLOCK ((mach_daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE))
+
+/*
+ * Addresses stored in inodes are capable of addressing fragments
+ * of `blocks'. File system blocks of at most size MAXBSIZE can
+ * be optionally broken into 2, 4, or 8 pieces, each of which is
+ * addressible; these pieces may be DEV_BSIZE, or some multiple of
+ * a DEV_BSIZE unit.
+ *
+ * Large files consist of exclusively large data blocks. To avoid
+ * undue wasted disk space, the last data block of a small file may be
+ * allocated as only as many fragments of a large block as are
+ * necessary. The file system format retains only a single pointer
+ * to such a fragment, which is a piece of a single large block that
+ * has been divided. The size of such a fragment is determinable from
+ * information in the inode, using the ``blksize(fs, ip, lbn)'' macro.
+ *
+ * The file system records space availability at the fragment level;
+ * to determine block availability, aligned fragments are examined.
+ *
+ * The root inode is the root of the file system.
+ * Inode 0 can't be used for normal purposes and
+ * historically bad blocks were linked to inode 1,
+ * thus the root inode is 2. (inode 1 is no longer used for
+ * this purpose, however numerous dump tapes make this
+ * assumption, so we are stuck with it)
+ */
+#define ROOTINO ((mach_ino_t)2) /* i number of all roots */
+
+/*
+ * MINBSIZE is the smallest allowable block size.
+ * In order to insure that it is possible to create files of size
+ * 2^32 with only two levels of indirection, MINBSIZE is set to 4096.
+ * MINBSIZE must be big enough to hold a cylinder group block,
+ * thus changes to (struct cg) must keep its size within MINBSIZE.
+ * Note that super blocks are always of size SBSIZE,
+ * and that both SBSIZE and MAXBSIZE must be >= MINBSIZE.
+ */
+#define MINBSIZE 4096
+
+/*
+ * The path name on which the file system is mounted is maintained
+ * in fs_fsmnt. MAXMNTLEN defines the amount of space allocated in
+ * the super block for this name.
+ * The limit on the amount of summary information per file system
+ * is defined by MAXCSBUFS. It is currently parameterized for a
+ * maximum of two million cylinders.
+ */
+#define MAXMNTLEN 512
+#define MAXCSBUFS 32
+
+/*
+ * Per cylinder group information; summarized in blocks allocated
+ * from first cylinder group data blocks. These blocks have to be
+ * read in from fs_csaddr (size fs_cssize) in addition to the
+ * super block.
+ *
+ * N.B. sizeof(struct csum) must be a power of two in order for
+ * the ``fs_cs'' macro to work (see below).
+ */
+struct csum
+ {
+ int cs_ndir; /* number of directories */
+ int cs_nbfree; /* number of free blocks */
+ int cs_nifree; /* number of free inodes */
+ int cs_nffree; /* number of free frags */
+ };
+
+/*
+ * Super block for a file system.
+ */
+#define FS_MAGIC 0x011954
+struct fs
+ {
+ int xxx1; /* struct fs *fs_link; */
+ int xxx2; /* struct fs *fs_rlink; */
+ mach_daddr_t fs_sblkno; /* addr of super-block in filesys */
+ mach_daddr_t fs_cblkno; /* offset of cyl-block in filesys */
+ mach_daddr_t fs_iblkno; /* offset of inode-blocks in filesys */
+ mach_daddr_t fs_dblkno; /* offset of first data after cg */
+ int fs_cgoffset; /* cylinder group offset in cylinder */
+ int fs_cgmask; /* used to calc mod fs_ntrak */
+ mach_time_t fs_time; /* last time written */
+ int fs_size; /* number of blocks in fs */
+ int fs_dsize; /* number of data blocks in fs */
+ int fs_ncg; /* number of cylinder groups */
+ int fs_bsize; /* size of basic blocks in fs */
+ int fs_fsize; /* size of frag blocks in fs */
+ int fs_frag; /* number of frags in a block in fs */
+/* these are configuration parameters */
+ int fs_minfree; /* minimum percentage of free blocks */
+ int fs_rotdelay; /* num of ms for optimal next block */
+ int fs_rps; /* disk revolutions per second */
+/* these fields can be computed from the others */
+ int fs_bmask; /* ``blkoff'' calc of blk offsets */
+ int fs_fmask; /* ``fragoff'' calc of frag offsets */
+ int fs_bshift; /* ``lblkno'' calc of logical blkno */
+ int fs_fshift; /* ``numfrags'' calc number of frags */
+/* these are configuration parameters */
+ int fs_maxcontig; /* max number of contiguous blks */
+ int fs_maxbpg; /* max number of blks per cyl group */
+/* these fields can be computed from the others */
+ int fs_fragshift; /* block to frag shift */
+ int fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */
+ int fs_sbsize; /* actual size of super block */
+ int fs_csmask; /* csum block offset */
+ int fs_csshift; /* csum block number */
+ int fs_nindir; /* value of NINDIR */
+ int fs_inopb; /* value of INOPB */
+ int fs_nspf; /* value of NSPF */
+/* yet another configuration parameter */
+ int fs_optim; /* optimization preference, see below */
+/* these fields are derived from the hardware */
+ int fs_npsect; /* # sectors/track including spares */
+ int fs_interleave; /* hardware sector interleave */
+ int fs_trackskew; /* sector 0 skew, per track */
+ int fs_headswitch; /* head switch time, usec */
+ int fs_trkseek; /* track-to-track seek, usec */
+/* sizes determined by number of cylinder groups and their sizes */
+ mach_daddr_t fs_csaddr; /* blk addr of cyl grp summary area */
+ int fs_cssize; /* size of cyl grp summary area */
+ int fs_cgsize; /* cylinder group size */
+/* these fields are derived from the hardware */
+ int fs_ntrak; /* tracks per cylinder */
+ int fs_nsect; /* sectors per track */
+ int fs_spc; /* sectors per cylinder */
+/* this comes from the disk driver partitioning */
+ int fs_ncyl; /* cylinders in file system */
+/* these fields can be computed from the others */
+ int fs_cpg; /* cylinders per group */
+ int fs_ipg; /* inodes per group */
+ int fs_fpg; /* blocks per group * fs_frag */
+/* this data must be re-computed after crashes */
+ struct csum fs_cstotal; /* cylinder summary information */
+/* these fields are cleared at mount time */
+ char fs_fmod; /* super block modified flag */
+ char fs_clean; /* file system is clean flag */
+ char fs_ronly; /* mounted read-only flag */
+ char fs_flags; /* currently unused flag */
+ char fs_fsmnt[MAXMNTLEN]; /* name mounted on */
+/* these fields retain the current block allocation info */
+ int fs_cgrotor; /* last cg searched */
+#if 1
+ int was_fs_csp[MAXCSBUFS];
+#else
+ struct csum *fs_csp[MAXCSBUFS]; /* list of fs_cs info buffers */
+#endif
+ int fs_cpc; /* cyl per cycle in postbl */
+ short fs_opostbl[16][8]; /* old rotation block list head */
+ long fs_sparecon[50]; /* reserved for future constants */
+ long fs_contigsumsize; /* size of cluster summary array */
+ long fs_maxsymlinklen; /* max length of an internal symlink */
+ long fs_inodefmt; /* format of on-disk inodes */
+ quad fs_maxfilesize; /* maximum representable file size */
+ quad fs_qbmask; /* ~fs_bmask - for use with quad size */
+ quad fs_qfmask; /* ~fs_fmask - for use with quad size */
+ long fs_state; /* validate fs_clean field */
+ int fs_postblformat; /* format of positional layout tables */
+ int fs_nrpos; /* number of rotaional positions */
+ int fs_postbloff; /* (short) rotation block list head */
+ int fs_rotbloff; /* (char) blocks for each rotation */
+ int fs_magic; /* magic number */
+ unsigned char fs_space[1]; /* list of blocks for each rotation */
+/* actually longer */
+ };
+/*
+ * Preference for optimization.
+ */
+#define FS_OPTTIME 0 /* minimize allocation time */
+#define FS_OPTSPACE 1 /* minimize disk fragmentation */
+
+/*
+ * Rotational layout table format types
+ */
+#define FS_42POSTBLFMT -1 /* 4.2BSD rotational table format */
+#define FS_DYNAMICPOSTBLFMT 1 /* dynamic rotational table format */
+/*
+ * Macros for access to superblock array structures
+ */
+#define fs_postbl(fs, cylno) \
+ (((fs)->fs_postblformat == FS_42POSTBLFMT) \
+ ? ((fs)->fs_opostbl[cylno]) \
+ : ((short *)((char *)(fs) + (fs)->fs_postbloff) + (cylno) * (fs)->fs_nrpos))
+#define fs_rotbl(fs) \
+ (((fs)->fs_postblformat == FS_42POSTBLFMT) \
+ ? ((fs)->fs_space) \
+ : ((unsigned char *)((char *)(fs) + (fs)->fs_rotbloff)))
+
+/*
+ * Convert cylinder group to base address of its global summary info.
+ *
+ * N.B. This macro assumes that sizeof(struct csum) is a power of two.
+ */
+#define fs_cs(fs, indx) \
+ fs_csp[(indx) >> (fs)->fs_csshift][(indx) & ~(fs)->fs_csmask]
+
+/*
+ * Cylinder group block for a file system.
+ */
+#define CG_MAGIC 0x090255
+struct cg
+ {
+ int xxx1; /* struct cg *cg_link; */
+ int cg_magic; /* magic number */
+ mach_time_t cg_time; /* time last written */
+ int cg_cgx; /* we are the cgx'th cylinder group */
+ short cg_ncyl; /* number of cyl's this cg */
+ short cg_niblk; /* number of inode blocks this cg */
+ int cg_ndblk; /* number of data blocks this cg */
+ struct csum cg_cs; /* cylinder summary information */
+ int cg_rotor; /* position of last used block */
+ int cg_frotor; /* position of last used frag */
+ int cg_irotor; /* position of last used inode */
+ int cg_frsum[MAXFRAG]; /* counts of available frags */
+ int cg_btotoff; /* (long) block totals per cylinder */
+ int cg_boff; /* (short) free block positions */
+ int cg_iusedoff; /* (char) used inode map */
+ int cg_freeoff; /* (char) free block map */
+ int cg_nextfreeoff; /* (char) next available space */
+ int cg_sparecon[16]; /* reserved for future use */
+ unsigned char cg_space[1]; /* space for cylinder group maps */
+/* actually longer */
+ };
+/*
+ * Macros for access to cylinder group array structures
+ */
+#define cg_blktot(cgp) \
+ (((cgp)->cg_magic != CG_MAGIC) \
+ ? (((struct ocg *)(cgp))->cg_btot) \
+ : ((int *)((char *)(cgp) + (cgp)->cg_btotoff)))
+#define cg_blks(fs, cgp, cylno) \
+ (((cgp)->cg_magic != CG_MAGIC) \
+ ? (((struct ocg *)(cgp))->cg_b[cylno]) \
+ : ((short *)((char *)(cgp) + (cgp)->cg_boff) + (cylno) * (fs)->fs_nrpos))
+#define cg_inosused(cgp) \
+ (((cgp)->cg_magic != CG_MAGIC) \
+ ? (((struct ocg *)(cgp))->cg_iused) \
+ : ((char *)((char *)(cgp) + (cgp)->cg_iusedoff)))
+#define cg_blksfree(cgp) \
+ (((cgp)->cg_magic != CG_MAGIC) \
+ ? (((struct ocg *)(cgp))->cg_free) \
+ : ((unsigned char *)((char *)(cgp) + (cgp)->cg_freeoff)))
+#define cg_chkmagic(cgp) \
+ ((cgp)->cg_magic == CG_MAGIC || ((struct ocg *)(cgp))->cg_magic == CG_MAGIC)
+
+/*
+ * The following structure is defined
+ * for compatibility with old file systems.
+ */
+struct ocg
+ {
+ int xxx1; /* struct ocg *cg_link; */
+ int xxx2; /* struct ocg *cg_rlink; */
+ mach_time_t cg_time; /* time last written */
+ int cg_cgx; /* we are the cgx'th cylinder group */
+ short cg_ncyl; /* number of cyl's this cg */
+ short cg_niblk; /* number of inode blocks this cg */
+ int cg_ndblk; /* number of data blocks this cg */
+ struct csum cg_cs; /* cylinder summary information */
+ int cg_rotor; /* position of last used block */
+ int cg_frotor; /* position of last used frag */
+ int cg_irotor; /* position of last used inode */
+ int cg_frsum[8]; /* counts of available frags */
+ int cg_btot[32]; /* block totals per cylinder */
+ short cg_b[32][8]; /* positions of free blocks */
+ char cg_iused[256]; /* used inode map */
+ int cg_magic; /* magic number */
+ unsigned char cg_free[1]; /* free block map */
+/* actually longer */
+ };
+
+/*
+ * Turn file system block numbers into disk block addresses.
+ * This maps file system blocks to device size blocks.
+ */
+#define fsbtodb(fs, b) ((b) << (fs)->fs_fsbtodb)
+#define dbtofsb(fs, b) ((b) >> (fs)->fs_fsbtodb)
+
+/*
+ * Cylinder group macros to locate things in cylinder groups.
+ * They calc file system addresses of cylinder group data structures.
+ */
+#define cgbase(fs, c) ((mach_daddr_t)((fs)->fs_fpg * (c)))
+#define cgstart(fs, c) \
+ (cgbase(fs, c) + (fs)->fs_cgoffset * ((c) & ~((fs)->fs_cgmask)))
+#define cgsblock(fs, c) (cgstart(fs, c) + (fs)->fs_sblkno) /* super blk */
+#define cgtod(fs, c) (cgstart(fs, c) + (fs)->fs_cblkno) /* cg block */
+#define cgimin(fs, c) (cgstart(fs, c) + (fs)->fs_iblkno) /* inode blk */
+#define cgdmin(fs, c) (cgstart(fs, c) + (fs)->fs_dblkno) /* 1st data */
+
+/*
+ * Macros for handling inode numbers:
+ * inode number to file system block offset.
+ * inode number to cylinder group number.
+ * inode number to file system block address.
+ */
+#define itoo(fs, x) ((x) % INOPB(fs))
+#define itog(fs, x) ((x) / (fs)->fs_ipg)
+#define itod(fs, x) \
+ ((mach_daddr_t)(cgimin(fs, itog(fs, x)) + \
+ (blkstofrags((fs), (((x) % (fs)->fs_ipg) / INOPB(fs))))))
+
+/*
+ * Give cylinder group number for a file system block.
+ * Give cylinder group block number for a file system block.
+ */
+#define dtog(fs, d) ((d) / (fs)->fs_fpg)
+#define dtogd(fs, d) ((d) % (fs)->fs_fpg)
+
+/*
+ * Extract the bits for a block from a map.
+ * Compute the cylinder and rotational position of a cyl block addr.
+ */
+#define blkmap(fs, map, loc) \
+ (((map)[(loc) / NBBY] >> ((loc) % NBBY)) & (0xff >> (NBBY - (fs)->fs_frag)))
+#define cbtocylno(fs, bno) \
+ ((bno) * NSPF(fs) / (fs)->fs_spc)
+#define cbtorpos(fs, bno) \
+ (((bno) * NSPF(fs) % (fs)->fs_spc / (fs)->fs_nsect * (fs)->fs_trackskew + \
+ (bno) * NSPF(fs) % (fs)->fs_spc % (fs)->fs_nsect * (fs)->fs_interleave) % \
+ (fs)->fs_nsect * (fs)->fs_nrpos / (fs)->fs_npsect)
+
+/*
+ * The following macros optimize certain frequently calculated
+ * quantities by using shifts and masks in place of divisions
+ * modulos and multiplications.
+ */
+#define blkoff(fs, loc) /* calculates (loc % fs->fs_bsize) */ \
+ ((loc) & ~(fs)->fs_bmask)
+#define fragoff(fs, loc) /* calculates (loc % fs->fs_fsize) */ \
+ ((loc) & ~(fs)->fs_fmask)
+#define lblkno(fs, loc) /* calculates (loc / fs->fs_bsize) */ \
+ ((loc) >> (fs)->fs_bshift)
+#define numfrags(fs, loc) /* calculates (loc / fs->fs_fsize) */ \
+ ((loc) >> (fs)->fs_fshift)
+#define blkroundup(fs, size) /* calculates roundup(size, fs->fs_bsize) */ \
+ (((size) + (fs)->fs_bsize - 1) & (fs)->fs_bmask)
+#define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \
+ (((size) + (fs)->fs_fsize - 1) & (fs)->fs_fmask)
+#define fragstoblks(fs, frags) /* calculates (frags / fs->fs_frag) */ \
+ ((frags) >> (fs)->fs_fragshift)
+#define blkstofrags(fs, blks) /* calculates (blks * fs->fs_frag) */ \
+ ((blks) << (fs)->fs_fragshift)
+#define fragnum(fs, fsb) /* calculates (fsb % fs->fs_frag) */ \
+ ((fsb) & ((fs)->fs_frag - 1))
+#define blknum(fs, fsb) /* calculates rounddown(fsb, fs->fs_frag) */ \
+ ((fsb) &~ ((fs)->fs_frag - 1))
+
+/*
+ * Determine the number of available frags given a
+ * percentage to hold in reserve
+ */
+#define freespace(fs, percentreserved) \
+ (blkstofrags((fs), (fs)->fs_cstotal.cs_nbfree) + \
+ (fs)->fs_cstotal.cs_nffree - ((fs)->fs_dsize * (percentreserved) / 100))
+
+/*
+ * Determining the size of a file block in the file system.
+ */
+#define blksize(fs, ip, lbn) \
+ (((lbn) >= NDADDR || (ip)->i_size >= ((lbn) + 1) << (fs)->fs_bshift) \
+ ? (fs)->fs_bsize \
+ : (fragroundup(fs, blkoff(fs, (ip)->i_size))))
+#define dblksize(fs, dip, lbn) \
+ (((lbn) >= NDADDR || (dip)->di_size >= ((lbn) + 1) << (fs)->fs_bshift) \
+ ? (fs)->fs_bsize \
+ : (fragroundup(fs, blkoff(fs, (dip)->di_size))))
+
+/*
+ * Number of disk sectors per block; assumes DEV_BSIZE byte sector size.
+ */
+#define NSPB(fs) ((fs)->fs_nspf << (fs)->fs_fragshift)
+#define NSPF(fs) ((fs)->fs_nspf)
+
+/*
+ * INOPB is the number of inodes in a secondary storage block.
+ */
+#define INOPB(fs) ((fs)->fs_inopb)
+#define INOPF(fs) ((fs)->fs_inopb >> (fs)->fs_fragshift)
+
+/*
+ * NINDIR is the number of indirects in a file system block.
+ */
+#define NINDIR(fs) ((fs)->fs_nindir)
Code Review / kvmfornfv.git / blobdiff