fix rotational layout code to work with disks with nsect % bsize != 0

[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 1d4dfa9..00107aa 100644 (file)
--- a/usr/src/sys/ufs/ffs/fs.h
+++ b/usr/src/sys/ufs/ffs/fs.h
@@ -1,6 +1,6 @@
 /* Copyright (c) 1981 Regents of the University of California */
 
 /* Copyright (c) 1981 Regents of the University of California */
 

-/*     fs.h    1.9     %G%     */
+/*     fs.h    1.11    %G%     */

 
 /*
  * Each disk drive contains some number of file systems.
 
 /*
  * Each disk drive contains some number of file systems.


@@ -14,28 +14,22 @@
  * 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(fs)]    Cylinder group block
- *     [IBLOCK(fs)..IBLOCK(fs)+fs.fs_ipg/INOPB(fs))
- *                     Inode blocks
- *     [IBLOCK(fs)+fs.fs_ipg/INOPB(fs)..fs.fs_fpg/fs.fs_frag)
- *                     Data blocks
- * The beginning of data blocks for cg in fs is also given by
- * the ``cgdmin(cg,fs)'' macro.
+ * For file system fs, the offsets of the various blocks of interest
+ * are given in the super block as:
+ *     [fs->fs_bblkno]         Boot sector
+ *     [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(cg, fs)'' macro.

  *
  *

- * The boot and super blocks are given in absolute disk addresses.
+ * The first boot and super blocks are given in absolute disk addresses.

  */
  */

-#define        BBLOCK          ((daddr_t)(0 * (MAXBSIZE / DEV_BSIZE)))
-#define        SBLOCK          ((daddr_t)(1 * (MAXBSIZE / DEV_BSIZE)))
-/*
- * The cylinder group and inode blocks are given in file system
- * addresses, and hence must be converted to disk addresses by
- * the ``fsbtodb(fs, bno)'' macro.
- */
-#define        CBLOCK(fs)      ((daddr_t)(dbtofsb(fs, 2 * (MAXBSIZE / DEV_BSIZE))))
-#define        IBLOCK(fs)      ((daddr_t)(CBLOCK(fs) + (fs)->fs_frag))
+#define BBSIZE         1024
+#define SBSIZE         8192
+#define        BBLOCK          ((daddr_t)(0))
+#define        SBLOCK          ((daddr_t)(BBLOCK + BBSIZE / DEV_BSIZE))

 
 /*
  * Addresses stored in inodes are capable of addressing fragments
 
 /*
  * Addresses stored in inodes are capable of addressing fragments


@@ -55,35 +49,73 @@
  * 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.
  *

+ * 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)
+ * The lost+found directory is given the next available
+ * inode when it is created by ``mkfs''.
+ */
+#define        ROOTINO         ((ino_t)2)      /* i number of all roots */
+#define LOSTFOUNDINO   (ROOTINO + 1)
+
+/*
+ * 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 severe performance degredations will be observed if the
+ * file system is run at greater than 90% full; thus the default
+ * value of fs_minfree is 10%.
+ *
+ * Empirically the best trade-off between block fragmentation and
+ * overall disk utilization at a loading of 90% comes with a
+ * fragmentation of 4, thus the default fragment size is a fourth
+ * of the block size.
+ */
+#define MINFREE                10
+#define DESFRAG                4
+
+/*
+ * Under current technology, most 300MB disks have 32 sectors and
+ * 19 tracks, thus these are the defaults used for fs_nsect and 
+ * fs_ntrak respectively.
+ */
+#define DFLNSECT       32
+#define DFLNTRAK       19
+
+/*
+ * Cylinder group related limits.
+ *

  * 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.
  * 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.

+ *
+ * ROTDELAY gives the minimum number of milliseconds to initiate
+ * another disk transfer on the same cylinder. It is used in
+ * determining the rotationally optimal layout for disk blocks
+ * within a file; the default of fs_rotdelay is 2ms.

  */
  */

-#define        NRPOS   8               /* number distinct rotational positions */
-
-/*
- * Information per cylinder group 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 */
-};
+#define        NRPOS           8       /* number distinct rotational positions */
+#define ROTDELAY       2

 
 /*
  * Each file system has a number of inodes statically allocated.
 
 /*
  * Each file system has a number of inodes statically allocated.

- * We allocate one inode slot per NBPI data bytes, expecting this
+ * We allocate one inode slot per NBPI bytes, expecting this

  * to be far more than we will ever need.
  * to be far more than we will ever need.

+ *
+ * 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).
+ *
+ * N.B.: MAXIPG must be a multiple of INOPB(fs).

  */
  */

-#define        NBPI    2048
+#define        NBPI            2048
+#define        MAXIPG          2048    /* max number inodes/cyl group */

 
 /*
  * MINBSIZE is the smallest allowable block size.
 
 /*
  * MINBSIZE is the smallest allowable block size.


@@ -100,33 +132,45 @@ struct csum {
 #define MINBSIZE       4096
 #define        DESCPG          16      /* desired fs_cpg */
 #define        MAXCPG          32      /* maximum fs_cpg */
 #define MINBSIZE       4096
 #define        DESCPG          16      /* desired fs_cpg */
 #define        MAXCPG          32      /* maximum fs_cpg */

- 
+

 /*
 /*

- * Super block for a file system.
+ * 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.

  *
  *

- * The super block is nominally located at disk block SBLOCK.
- * 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)
+ * N.B. sizeof(struct csum) must be a power of two in order for
+ * the ``fs_cs'' macro to work (see below).

  */
  */

-#define        ROOTINO ((ino_t)2)      /* i number of all roots */
+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        0x110854
 struct fs
 {
        long    fs_magic;               /* magic number */
 #define        FS_MAGIC        0x110854
 struct fs
 {
        long    fs_magic;               /* magic number */

-       daddr_t fs_sblkno;              /* offset of super-block in filesys */
+       daddr_t fs_bblkno;              /* abs addr of boot-block in filesys */
+       daddr_t fs_sblkno;              /* abs 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 data-blocks in filesys */

        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 */
        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 */
+       short   fs_frag;                /* number of frags in a block in fs */

        short   fs_minfree;             /* minimum percentage of free blocks */
        short   fs_rotdelay;            /* num of ms for optimal next block */
        short   fs_minfree;             /* minimum percentage of free blocks */
        short   fs_rotdelay;            /* num of ms for optimal next block */

+       short   fs_rps;                 /* disk revolutions per second */

 /* 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 */
 /* 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 */


@@ -150,13 +194,15 @@ struct    fs
 /* 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 */
 /* 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 */
+       short   fs_cpc;                 /* cyl per cycle in postbl */
+       short   fs_postbl[MAXCPG][NRPOS];/* head of blocks for each rotation */
+       u_char  fs_rotbl[1];            /* list of blocks for each rotation */

 /* actually longer */
 };
 
 /*
  * convert cylinder group to base address of its global summary info.
 /* actually longer */
 };
 
 /*
  * 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) \
  * N.B. This macro assumes that sizeof(struct csum) is a power of two.
  */
 #define fs_cs(fs, indx) \


@@ -164,64 +210,19 @@ struct    fs
        [(indx) % ((fs)->fs_bsize / sizeof(struct csum))]
 
 /*
        [(indx) % ((fs)->fs_bsize / sizeof(struct csum))]
 
 /*

- * Cylinder group macros to locate things in cylinder groups.
+ * MAXBPC bounds the size of the rotational layout tables and
+ * is limited by the fact that the super block is of size SBSIZE.
+ * The size of these tables is INVERSELY proportional to the block
+ * size of the file system. It is aggravated by sector sizes that
+ * are not powers of two, as this increases the number of cylinders
+ * included before the rotational pattern repeats (fs_cpc).
+ * Its size is derived from the number of bytes remaining in (struct fs)

  */
  */

-
-/* 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) + dbtofsb(fs, SBLOCK))
-
-/* convert cylinder group to index of its cg block */
-#define        cgtod(c,fs)     \
-       (cgbase(c,fs) + CBLOCK(fs))
-
-/* give address of first inode block in cylinder group */
-#define        cgimin(c,fs)    \
-       (cgbase(c,fs) + IBLOCK(fs))
-
-/* give address of first data block in cylinder group */
-#define        cgdmin(c,fs)    (cgimin(c,fs) + (fs)->fs_ipg / INOPF(fs))
-
-/* turn inode number into cylinder group number */
-#define        itog(x,fs)      ((x)/(fs)->fs_ipg)
-
-/* turn inode number into file system block address */
-#define        itod(x,fs)      ((daddr_t)(cgimin(itog(x,fs),fs)+(fs)->fs_frag*((x)%(fs)->fs_ipg/INOPB(fs))))
-
-/* turn inode number into file system block offset */
-#define        itoo(x,fs)      ((x)%INOPB(fs))
-
-/* give cylinder group number for a file system block */
-#define        dtog(d,fs)      ((d)/(fs)->fs_fpg)
-
-/* give cylinder group block number for a file system block */
-#define        dtogd(d,fs)     ((d)%(fs)->fs_fpg)
+#define        MAXBPC  (SBSIZE - sizeof (struct fs))

 
 /*
 
 /*

- * Cylinder group related limits.
+ * Cylinder group block for a file system.

  */
  */

-
-/*
- * 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).
- *
- * N.B.: MAXIPG must be a multiple of INOPB.
- */
-#define        MAXIPG  2048            /* max number inodes/cyl group */
-
-/*
- * 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.
- */
-#define        MAXBPG(fs) \
-       (NBBY*((fs)->fs_bsize-(sizeof (struct cg)))/(fs)->fs_frag)
-

 #define        CG_MAGIC        0x092752
 struct cg {
        long    cg_magic;               /* magic number */
 #define        CG_MAGIC        0x092752
 struct cg {
        long    cg_magic;               /* magic number */


@@ -240,7 +241,117 @@ struct    cg {
        char    cg_free[1];             /* free block map */
 /* actually longer */
 };
        char    cg_free[1];             /* free block map */
 /* actually longer */
 };

-#define        cgsize(fp)      (sizeof (struct cg) + ((fp)->fs_fpg+NBBY-1)/NBBY)
+
+/*
+ * 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.
+ */
+#define        MAXBPG(fs) \
+       (NBBY * ((fs)->fs_bsize - (sizeof (struct cg))) / (fs)->fs_frag)
+
+/*
+ * 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_fsize / DEV_BSIZE))
+#define        dbtofsb(fs, b)  ((b) / ((fs)->fs_fsize / DEV_BSIZE))
+
+/*
+ * Cylinder group macros to locate things in cylinder groups.
+ *
+ * cylinder group to disk block address of spare boot block
+ * and super block
+ * Note that these are in absolute addresses, and can NOT
+ * in general be expressable in terms of file system addresses.
+ */
+#define        cgbblock(c,fs)  (fsbtodb(fs, cgbase(c,fs)) + (fs)->fs_bblkno)
+#define        cgsblock(c,fs)  (fsbtodb(fs, cgbase(c,fs)) + (fs)->fs_sblkno)
+
+/*
+ * cylinder group to disk block at very beginning
+ */
+#define        cgbase(c,fs)    ((daddr_t)((fs)->fs_fpg * (c)))
+
+/*
+ * convert cylinder group to index of its cg block
+ */
+#define        cgtod(c,fs)     (cgbase(c,fs) + (fs)->fs_cblkno)
+
+/*
+ * give address of first inode block in cylinder group
+ */
+#define        cgimin(c,fs)    (cgbase(c,fs) + (fs)->fs_iblkno)
+
+/*
+ * give address of first data block in cylinder group
+ */
+#define        cgdmin(c,fs)    (cgbase(c,fs) + (fs)->fs_dblkno)
+
+/*
+ * turn inode number into cylinder group number
+ */
+#define        itog(x,fs)      ((x) / (fs)->fs_ipg)
+
+/*
+ * turn inode number into file system block address
+ */
+#define        itod(x,fs) \
+       ((daddr_t)(cgimin(itog(x,fs),fs) + \
+       (x) % (fs)->fs_ipg / INOPB(fs) * (fs)->fs_frag))
+
+/*
+ * turn inode number into file system block offset
+ */
+#define        itoo(x,fs)      ((x) % INOPB(fs))
+
+/*
+ * give cylinder group number for a file system block
+ */
+#define        dtog(d,fs)      ((d) / (fs)->fs_fpg)
+
+/*
+ * give cylinder group block number for a file system block
+ */
+#define        dtogd(d,fs)     ((d) % (fs)->fs_fpg)
+
+/*
+ * compute the cylinder and rotational position of a cyl block addr
+ */
+#define cbtocylno(fs, bno) \
+       ((bno) * NSPF(fs) / (fs)->fs_spc)
+#define cbtorpos(fs, bno) \
+       ((bno) * NSPF(fs) % (fs)->fs_nsect * NRPOS / (fs)->fs_nsect)
+
+/*
+ * 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_bsize) \
+               ? (fs)->fs_bsize \
+               : (roundup((ip)->i_size % (fs)->fs_bsize, (fs)->fs_fsize)))
+#define dblksize(fs, dip, lbn) \
+       (((lbn) >= NDADDR || (dip)->di_size >= ((lbn) + 1) * (fs)->fs_bsize) \
+               ? (fs)->fs_bsize \
+               : (roundup((dip)->di_size % (fs)->fs_bsize, (fs)->fs_fsize)))
+
+/*
+ * number of disk sectors per block; assumes DEV_BSIZE byte sector size
+ */
+#define        NSPB(fs)        ((fs)->fs_bsize / DEV_BSIZE)
+#define        NSPF(fs)        ((fs)->fs_fsize / DEV_BSIZE)
+
+/*
+ * INOPB is the number of inodes in a secondary storage block
+ */
+#define        INOPB(fs)       ((fs)->fs_bsize / sizeof (struct dinode))
+#define        INOPF(fs)       ((fs)->fs_fsize / sizeof (struct dinode))
+
+/*
+ * NINDIR is the number of indirects in a file system block
+ */
+#define        NINDIR(fs)      ((fs)->fs_bsize / sizeof (daddr_t))

 
 #ifdef KERNEL
 struct fs *getfs();
 
 #ifdef KERNEL
 struct fs *getfs();