-/* Copyright (c) 1981 Regents of the University of California */
-
-/* fs.h 1.6 %G% */
+/*
+ * Copyright (c) 1982, 1986, 1993
+ * The 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 8.7 (Berkeley) 4/19/94
+ */
/*
* Each disk drive contains some number of file systems.
* 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 mkfs time and the critical
+ * 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 and a cylinder group number cg:
- * [BBLOCK] Boot sector and bad block information
- * [SBLOCK] Super-block
- * [CBLOCK] Cylinder group block
- * [IBLOCK..IBLOCK+fs.fs_ipg/INOPB)
- * Inode blocks
- * [IBLOCK+fs.fs_ipg/INOPB..fs.fs_fpg/FRAG)
- * Data blocks
- * The beginning of data blocks for cg in fs is also given by cgdmin(cg,fs).
- */
-#define BBLOCK ((daddr_t)(0*FRAG))
-#define SBLOCK ((daddr_t)(1*FRAG))
-#define CBLOCK ((daddr_t)(2*FRAG))
-#define IBLOCK ((daddr_t)(3*FRAG))
-
-/*
- * Addresses stored in inodes are capable of addressing fragments of `blocks.'
- * File system blocks of size BSIZE can be broken into FRAG pieces,
- * each of which is addressible; these pieces may be sectors, or some
- * multiple of a sector size (e.g. 1k byte units).
+ * 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.
*
- * Large files consist of exclusively large (BSIZE) data blocks. To avoid
- * undue fragmentation, the last data block of a small file may be
- * allocated as only as many pieces
- * 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
- * BSIZE block which has been divided. The size of such a fragment is
- * determinable from information in the inode.
+ * 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.
- *
- * For each cylinder we keep track of the availability of blocks at different
- * rotational positions, so that we can lay out the data to be picked
- * up with minimum rotational latency. NRPOS is the number of rotational
- * positions which we distinguish. With NRPOS 8 the resolution of our
- * summary information is 2ms for a typical 3600 rpm drive.
*/
-#define NRPOS 8 /* number distinct rotational positions */
/*
- * Information per cylinder group summarized in blocks allocated
+ * 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
+
+/*
+ * A summary of contiguous blocks of various sizes is maintained
+ * in each cylinder group. Normally this is set by the initial
+ * value of fs_maxcontig. To conserve space, a maximum summary size
+ * is set by FS_MAXCONTIG.
+ */
+#define FS_MAXCONTIG 16
+
+/*
+ * MINFREE gives the minimum acceptable percentage of file system
+ * blocks which may be free. If the freelist drops below this level
+ * only the superuser may continue to allocate blocks. This may
+ * be set to 0 if no reserve of free blocks is deemed necessary,
+ * however throughput drops by fifty percent if the file system
+ * is run at between 95% and 100% full; thus the minimum default
+ * value of fs_minfree is 5%. However, to get good clustering
+ * performance, 10% is a better choice. hence we use 10% as our
+ * default value. With 10% free space, fragmentation is not a
+ * problem, so we choose to optimize for time.
+ */
+#define MINFREE 5
+#define DEFAULTOPT FS_OPTTIME
+
+/*
+ * Per cylinder group information; summarized in blocks allocated
* from first cylinder group data blocks. These blocks have to be
- * specially noticed in mkfs, icheck and fsck.
+ * 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_nifree; /* number of free inodes */
long cs_nffree; /* number of free frags */
};
-#define cssize(fs) ((fs)->fs_ncg*sizeof(struct csum))
-#define csaddr(fs) (cgdmin(0, fs))
-/*
- * Each file system has a number of inodes statically allocated.
- * We allocate one inode slot per NBPI data bytes, expecting this
- * to be far more than we will ever need. Actually, the directory
- * structure has inode numbers kept in 16 bits, so no more than
- * 65K inodes are possible, and this usually cuts off well above
- * the number suggested by NBPI.
- *
- * THE DIRECTORY STRUCTURE SHOULD BE CHANGED SOON TO ALLOW
- * LARGER INODE NUMBERS (SEE DIR.H).
- */
-#define NBPI 2048
-
-#define DESCPG 16 /* desired fs_cpg */
-#define MAXCPG 32 /* maximum fs_cpg */
-/* MAXCPG is limited only to dimension an array in (struct cg); */
-/* it can be made larger as long as that structures size remains sane. */
-
/*
* Super block for a file system.
- *
- * The super block is nominally located at disk block 1 although
- * this is naive due to bad blocks. Inode 0 can't be used for normal
- * purposes, 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) /* i number of all roots */
-
-#define FS_MAGIC 0x110854
-struct fs
-{
- long fs_magic; /* magic number */
- daddr_t fs_sblkno; /* offset of super-block in filesys */
+ */
+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 should be derived from the hardware */
- short fs_ntrak; /* tracks per cylinder */
- short fs_nsect; /* sectors per track */
+/* 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 */
- short fs_cpg; /* cylinders per group */
- short fs_ipg; /* inodes per group */
- long fs_fpg; /* blocks per group*FRAG */
+ 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_fsmnt[34]; /* name mounted on */
+ 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[NBUF]; /* list of fs_cs info buffers */
- short fs_postbl[NRPOS]; /* head of blocks for each rotation */
- short fs_rotbl[1]; /* list of blocks for each rotation */
+ 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[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 */
+ u_quad_t fs_maxfilesize; /* maximum representable file size */
+ quad_t fs_qbmask; /* ~fs_bmask - for use with quad size */
+ quad_t fs_qfmask; /* ~fs_fmask - for use with quad size */
+ long fs_state; /* validate fs_clean field */
+ long fs_postblformat; /* format of positional layout tables */
+ long fs_nrpos; /* number of rotational 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 */
};
-#define fs_cs(indx) fs_csp[(indx) / (BSIZE / sizeof(struct csum))] \
- [(indx) % (BSIZE / sizeof(struct csum))]
-
/*
- * Cylinder group macros to locate things in cylinder groups.
+ * Filesystem idetification
*/
+#define FS_MAGIC 0x011954 /* the fast filesystem magic number */
+#define FS_OKAY 0x7c269d38 /* superblock checksum */
+#define FS_42INODEFMT -1 /* 4.2BSD inode format */
+#define FS_44INODEFMT 2 /* 4.4BSD inode format */
+/*
+ * Preference for optimization.
+ */
+#define FS_OPTTIME 0 /* minimize allocation time */
+#define FS_OPTSPACE 1 /* minimize disk fragmentation */
-/* cylinder group to disk block at very beginning */
-#define cgbase(c,fs) ((daddr_t)((fs)->fs_fpg*(c)))
-
-/* cylinder group to spare super block address */
-#define cgsblock(c,fs) \
- (cgbase(c,fs) + SBLOCK)
-
-/* convert cylinder group to index of its cg block */
-#define cgtod(c,fs) \
- (cgbase(c,fs) + CBLOCK)
-
-/* give address of first inode block in cylinder group */
-#define cgimin(c,fs) \
- (cgbase(c,fs) + IBLOCK)
-
-/* give address of first data block in cylinder group */
-#define cgdmin(c,fs) (cgimin(c,fs) + (fs)->fs_ipg / INOPF)
-
-/* turn inode number into cylinder group number */
-#define itog(x,fs) ((x)/(fs)->fs_ipg)
-
-/* turn inode number into disk block address */
-#define itod(x,fs) (cgimin(itog(x,fs),fs)+FRAG*((x)%(fs)->fs_ipg/INOPB))
-
-/* turn inode number into disk block offset */
-#define itoo(x) ((x)%INOPB)
-
-/* give cylinder group number for a disk block */
-#define dtog(d,fs) ((d)/(fs)->fs_fpg)
-
-/* give cylinder group block number for a disk block */
-#define dtogd(d,fs) ((d)%(fs)->fs_fpg)
+/*
+ * 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)))
/*
- * Cylinder group related limits.
+ * The size of a cylinder group is calculated by CGSIZE. The maximum size
+ * is limited by the fact that cylinder groups are at most one block.
+ * Its size is derived from the size of the maps maintained in the
+ * cylinder group and the (struct cg) size.
*/
+#define CGSIZE(fs) \
+ /* base cg */ (sizeof(struct cg) + sizeof(long) + \
+ /* blktot size */ (fs)->fs_cpg * sizeof(long) + \
+ /* blks size */ (fs)->fs_cpg * (fs)->fs_nrpos * sizeof(short) + \
+ /* inode map */ howmany((fs)->fs_ipg, NBBY) + \
+ /* block map */ howmany((fs)->fs_cpg * (fs)->fs_spc / NSPF(fs), NBBY) +\
+ /* if present */ ((fs)->fs_contigsumsize <= 0 ? 0 : \
+ /* cluster sum */ (fs)->fs_contigsumsize * sizeof(long) + \
+ /* cluster map */ howmany((fs)->fs_cpg * (fs)->fs_spc / NSPB(fs), NBBY)))
/*
- * MAXIPG bounds the number of inodes per cylinder group, and
- * is needed only to keep the structure simpler by having the
- * only a single variable size element (the free bit map).
+ * Convert cylinder group to base address of its global summary info.
*
- * N.B.: MAXIPG must be a multiple of INOPB.
+ * N.B. This macro assumes that sizeof(struct csum) is a power of two.
*/
-#define MAXIPG 2048 /* max number inodes/cyl group */
+#define fs_cs(fs, indx) \
+ fs_csp[(indx) >> (fs)->fs_csshift][(indx) & ~(fs)->fs_csmask]
/*
- * MAXBPG bounds the number of blocks of data per cylinder group,
- * and is limited by the fact that cylinder groups are at most one block.
- * Its size is derived from the size of blocks and the (struct cg) size,
- * by the number of remaining bits.
+ * Cylinder group block for a file system.
*/
-#define MAXBPG (NBBY*(BSIZE-(sizeof (struct cg)))/FRAG)
-
-#define CG_MAGIC 0x092752
+#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 */
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[FRAG]; /* counts of available frags */
- short cg_b[MAXCPG][NRPOS]; /* positions of free blocks */
- char cg_iused[MAXIPG/NBBY]; /* used inode map */
- char cg_free[1]; /* free block map */
+ 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_clustersumoff; /* (long) counts of avail clusters */
+ long cg_clusteroff; /* (char) free cluster map */
+ long cg_nclusterblks; /* number of clusters this cg */
+ long cg_sparecon[13]; /* reserved for future use */
+ u_char cg_space[1]; /* space for cylinder group maps */
/* actually longer */
};
-#define cgsize(fp) (sizeof (struct cg) + ((fp)->fs_fpg+NBBY-1)/NBBY)
+/*
+ * 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)
+#define cg_clustersfree(cgp) \
+ ((u_char *)((char *)(cgp) + (cgp)->cg_clusteroff))
+#define cg_clustersum(cgp) \
+ ((long *)((char *)(cgp) + (cgp)->cg_clustersumoff))
+
+/*
+ * 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 cgdmin(fs, c) (cgstart(fs, c) + (fs)->fs_dblkno) /* 1st data */
+#define cgimin(fs, c) (cgstart(fs, c) + (fs)->fs_iblkno) /* inode blk */
+#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 cgstart(fs, c) \
+ (cgbase(fs, c) + (fs)->fs_cgoffset * ((c) & ~((fs)->fs_cgmask)))
+
+/*
+ * 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 ino_to_cg(fs, x) ((x) / (fs)->fs_ipg)
+#define ino_to_fsba(fs, x) \
+ ((daddr_t)(cgimin(fs, ino_to_cg(fs, x)) + \
+ (blkstofrags((fs), (((x) % (fs)->fs_ipg) / INOPB(fs))))))
+#define ino_to_fsbo(fs, x) ((x) % 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_qbmask)
+#define fragoff(fs, loc) /* calculates (loc % fs->fs_fsize) */ \
+ ((loc) & (fs)->fs_qfmask)
+#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_qbmask) & (fs)->fs_bmask)
+#define fragroundup(fs, size) /* calculates roundup(size, fs->fs_fsize) */ \
+ (((size) + (fs)->fs_qfmask) & (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)
-#ifdef KERNEL
-struct fs *getfs();
-#endif
+extern int inside[], around[];
+extern u_char *fragtbl[];