BSD 4_4_Lite1 release

[unix-history] / usr / src / sys / ufs / ffs / fs.h

diff --git a/usr/src/sys/ufs/ffs/fs.h b/usr/src/sys/ufs/ffs/fs.h
index 99adbe1..bef052f 100644 (file)
--- a/usr/src/sys/ufs/ffs/fs.h
+++ b/usr/src/sys/ufs/ffs/fs.h
@@ -1,6 +1,37 @@
-/* Copyright (c) 1981 Regents of the University of California */
-
-/*     fs.h    1.8     %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.
 
 /*
  * Each disk drive contains some number of file systems.


@@ -10,54 +41,101 @@
  * 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
  * 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.
  *
  * 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.
  *
  * 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
  * 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 */
  */
 struct csum {
        long    cs_ndir;        /* number of directories */


@@ -65,131 +143,158 @@ struct csum {
        long    cs_nifree;      /* number of free inodes */
        long    cs_nffree;      /* number of free frags */
 };
        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.
- */
-#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.
 /*
  * 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 */
        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 */
 /* 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 */
        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 */
        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 */
 /* 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_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 */
 /* 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 */
 };
 /* 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)      ((daddr_t)(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 {

+       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_magic;               /* magic number */
        time_t  cg_time;                /* time last written */
        long    cg_cgx;                 /* we are the cgx'th cylinder group */


@@ -200,14 +305,185 @@ struct   cg {
        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_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 */
 };
 /* 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[];