home *** CD-ROM | disk | FTP | other *** search
- /*
- * Copyright (c) 1982, 1986 Regents of the University of California.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by the University of
- * California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * @(#)fs.h 7.12 (Berkeley) 5/8/91
- */
-
- /*
- * 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 ((off_t)(0))
- #define SBOFF ((off_t)(BBOFF + BBSIZE))
- #define BBLOCK ((daddr_t)(0))
- #define SBLOCK ((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 ((ino_t)2)
-
- /*
- * 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 {
- long cs_ndir; /* number of directories */
- long cs_nbfree; /* number of free blocks */
- long cs_nifree; /* number of free inodes */
- long cs_nffree; /* number of free frags */
- };
-
- /*
- * Super block for a file system.
- */
- #define FS_MAGIC 0x011954
- #define FSOKAY 0x7c269d38
- struct fs
- {
- struct fs *fs_link; /* linked list of file systems */
- struct fs *fs_rlink; /* used for incore super blocks */
- daddr_t fs_sblkno; /* addr of super-block in filesys */
- daddr_t fs_cblkno; /* offset of cyl-block in filesys */
- daddr_t fs_iblkno; /* offset of inode-blocks in filesys */
- daddr_t fs_dblkno; /* offset of first data after cg */
- long fs_cgoffset; /* cylinder group offset in cylinder */
- long fs_cgmask; /* used to calc mod fs_ntrak */
- time_t fs_time; /* last time written */
- long fs_size; /* number of blocks in fs */
- long fs_dsize; /* number of data blocks in fs */
- long fs_ncg; /* number of cylinder groups */
- long fs_bsize; /* size of basic blocks in fs */
- long fs_fsize; /* size of frag blocks in fs */
- long fs_frag; /* number of frags in a block in fs */
- /* these are configuration parameters */
- long fs_minfree; /* minimum percentage of free blocks */
- long fs_rotdelay; /* num of ms for optimal next block */
- long fs_rps; /* disk revolutions per second */
- /* these fields can be computed from the others */
- long fs_bmask; /* ``blkoff'' calc of blk offsets */
- long fs_fmask; /* ``fragoff'' calc of frag offsets */
- long fs_bshift; /* ``lblkno'' calc of logical blkno */
- long fs_fshift; /* ``numfrags'' calc number of frags */
- /* these are configuration parameters */
- long fs_maxcontig; /* max number of contiguous blks */
- long fs_maxbpg; /* max number of blks per cyl group */
- /* these fields can be computed from the others */
- long fs_fragshift; /* block to frag shift */
- long fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */
- long fs_sbsize; /* actual size of super block */
- long fs_csmask; /* csum block offset */
- long fs_csshift; /* csum block number */
- long fs_nindir; /* value of NINDIR */
- long fs_inopb; /* value of INOPB */
- long fs_nspf; /* value of NSPF */
- /* yet another configuration parameter */
- long fs_optim; /* optimization preference, see below */
- /* these fields are derived from the hardware */
- long fs_npsect; /* # sectors/track including spares */
- long fs_interleave; /* hardware sector interleave */
- long fs_trackskew; /* sector 0 skew, per track */
- long fs_headswitch; /* head switch time, usec */
- long fs_trkseek; /* track-to-track seek, usec */
- /* sizes determined by number of cylinder groups and their sizes */
- daddr_t fs_csaddr; /* blk addr of cyl grp summary area */
- long fs_cssize; /* size of cyl grp summary area */
- long fs_cgsize; /* cylinder group size */
- /* these fields are derived from the hardware */
- long fs_ntrak; /* tracks per cylinder */
- long fs_nsect; /* sectors per track */
- long fs_spc; /* sectors per cylinder */
- /* this comes from the disk driver partitioning */
- long fs_ncyl; /* cylinders in file system */
- /* these fields can be computed from the others */
- long fs_cpg; /* cylinders per group */
- long fs_ipg; /* inodes per group */
- long 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 */
- long fs_cgrotor; /* last cg searched */
- struct csum *fs_csp[MAXCSBUFS];/* list of fs_cs info buffers */
- long fs_cpc; /* cyl per cycle in postbl */
- short fs_opostbl[16][8]; /* old rotation block list head */
- long fs_sparecon[55]; /* reserved for future constants */
- long fs_state; /* validate fs_clean field */
- quad fs_qbmask; /* ~fs_bmask - for use with quad size */
- quad fs_qfmask; /* ~fs_fmask - for use with quad size */
- long fs_postblformat; /* format of positional layout tables */
- long fs_nrpos; /* number of rotaional positions */
- long fs_postbloff; /* (short) rotation block list head */
- long fs_rotbloff; /* (u_char) blocks for each rotation */
- long fs_magic; /* magic number */
- u_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) \
- : ((u_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 {
- struct cg *cg_link; /* linked list of cyl groups */
- long cg_magic; /* magic number */
- time_t cg_time; /* time last written */
- long 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 */
- long cg_ndblk; /* number of data blocks this cg */
- struct csum cg_cs; /* cylinder summary information */
- long cg_rotor; /* position of last used block */
- long cg_frotor; /* position of last used frag */
- long cg_irotor; /* position of last used inode */
- long cg_frsum[MAXFRAG]; /* counts of available frags */
- long cg_btotoff; /* (long) block totals per cylinder */
- long cg_boff; /* (short) free block positions */
- long cg_iusedoff; /* (char) used inode map */
- long cg_freeoff; /* (u_char) free block map */
- long cg_nextfreeoff; /* (u_char) next available space */
- long cg_sparecon[16]; /* reserved for future use */
- u_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) \
- : ((long *)((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) \
- : ((u_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 {
- struct ocg *cg_link; /* linked list of cyl groups */
- struct ocg *cg_rlink; /* used for incore cyl groups */
- time_t cg_time; /* time last written */
- long 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 */
- long cg_ndblk; /* number of data blocks this cg */
- struct csum cg_cs; /* cylinder summary information */
- long cg_rotor; /* position of last used block */
- long cg_frotor; /* position of last used frag */
- long cg_irotor; /* position of last used inode */
- long cg_frsum[8]; /* counts of available frags */
- long cg_btot[32]; /* block totals per cylinder */
- short cg_b[32][8]; /* positions of free blocks */
- char cg_iused[256]; /* used inode map */
- long cg_magic; /* magic number */
- u_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) ((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) \
- ((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 lblktosize(fs, blk) /* calculates (blk * fs->fs_bsize) */ \
- ((blk) << (fs)->fs_bshift)
- #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)
-