rom/filesys/SFS/FS/blockstructure.h

   1 #ifndef _BLOCKSTRUCTURE_H
   2 #define _BLOCKSTRUCTURE_H
   3
   4 #include <exec/types.h>
   5
   6 /* a BLCK is a block number.  Blocksize in bytes = SectorSize * SectorsPerBlock.
   7
   8    BLCK pointers are used throughout the filesystem.  All structures which
   9    require to associate themselves with another structure do so using BLCK
  10    pointers.  Byte pointers are not used. */
  11
  12 typedef ULONG BLCK;
  13 typedef BLCK BLCKn;
  14
  15
  16 /* Below is the standard block header.  This header is found before EVERY
  17    type of block used in the filesystem, except data blocks.
  18
  19    The id field is used to check if the block is of the correct type when
  20    it is being referred to using a BLCK pointer.
  21
  22    The checksum field is the SUM of all LONGs in a block plus one, and then
  23    negated.  When applying a checksum the checksum field itself should be
  24    set to zero.  To check to see if the checksum is okay, the sum of all
  25    longs in a block should be zero.
  26
  27    The ownblock BLCK pointer points to the block itself.  This field is an
  28    extra safety check to ensure we are using a valid block. */
  29
  30 struct fsBlockHeader {
  31   ULONG id;         /* 4 character id string of this block */
  32   ULONG be_checksum;   /* The checksum */
  33   BLCK  be_ownblock;   /* The blocknumber of the block this block is stored at */
  34 };
  35
  36
  37
  38 /* Now follows the structure of the Boot block.  The Boot block is always
  39    located at block offset 0.  It contains only a version number at the
  40    moment to identify the block structure of the disk. */
  41
  42 /*
  43 struct fsBootBlock {
  44   struct fsBlockHeader bheader;
  45
  46   UWORD version;                   // Version number of the filesystem block structure
  47 };
  48 */
  49
  50 #define STRUCTURE_VERSION (3)
  51
  52
  53
  54 /* The fsRootInfo structure has all kinds of information about the format
  55    of the disk. */
  56
  57 struct fsRootInfo {
  58   ULONG be_deletedblocks;             /* Amount in blocks which deleted files consume. */
  59   ULONG be_deletedfiles;              /* Number of deleted files in recycled. */
  60   ULONG be_freeblocks;                /* Cached number of free blocks on disk. */
  61
  62   ULONG be_datecreated;
  63
  64   BLCK  be_lastallocatedblock;        /* Block which was most recently allocated */
  65   BLCK  be_lastallocatedadminspace;   /* AdminSpaceContainer which most recently was used to allocate a block */
  66   ULONG be_lastallocatedextentnode;   /* ExtentNode which was most recently created */
  67   ULONG be_lastallocatedobjectnode;   /* ObjectNode which was most recently created */
  68
  69   BLCK  be_rovingpointer;
  70 };
  71
  72
  73
  74 /* An SFS disk has two Root blocks, one located at the start of
  75    the partition and one at the end.  On startup the fs will check
  76    both Roots to see if it is a valid SFS disk.  If either one is
  77    missing SFS can still continue.
  78
  79    A Root block could be missing on purpose.  For example, if you
  80    extend the partition at the end (adding a few MB's) then SFS
  81    can detect this with the information stored in the Root block
  82    located at the beginning (since only the end-offset has changed).
  83    Same goes for the other way around, as long as you don't change
  84    start and end point at the same time.
  85
  86    When a Root block is missing because the partition has been
  87    made a bit larger, then SFS will in the future be able to
  88    'resize' itself without re-formatting the disk.
  89
  90    Note: ownblock pointers won't be correct anymore when start of
  91          partition has changed... */
  92
  93 struct fsRootBlock {
  94   struct fsBlockHeader bheader;
  95
  96   UWORD be_version;              /* Version number of the filesystem block structure */
  97   UWORD be_sequencenumber;       /* The Root with the highest sequencenumber is valid */
  98
  99   ULONG be_datecreated;          /* Creation date (when first formatted).  Cannot be changed. */
 100   UBYTE bits;                 /* various settings, see defines below. */
 101   UBYTE pad1;
 102   UWORD be_pad2;
 103
 104   ULONG be_reserved1[2];
 105
 106   ULONG be_firstbyteh;           /* The first byte of our partition from the start of the */
 107   ULONG be_firstbyte;            /* disk.  firstbyteh = upper 32 bits, firstbyte = lower 32 bits. */
 108
 109   ULONG be_lastbyteh;            /* The last byte of our partition, excluding this one. */
 110   ULONG be_lastbyte;
 111
 112   BLCK  be_totalblocks;          /* size of this partition in blocks */
 113   ULONG be_blocksize;            /* blocksize used */
 114
 115   ULONG be_reserved2[2];
 116   ULONG be_reserved3[8];
 117
 118   BLCK  be_bitmapbase;           /* location of the bitmap */
 119   BLCK  be_adminspacecontainer;  /* location of first adminspace container */
 120   BLCK  be_rootobjectcontainer;  /* location of the root objectcontainer */
 121   BLCK  be_extentbnoderoot;      /* location of the root of the extentbnode B-tree */
 122   BLCK  be_objectnoderoot;       /* location of the root of the objectnode tree */
 123
 124   ULONG be_reserved4[3];
 125 };
 126
 127 #define ROOTBITS_CASESENSITIVE (128)   /* When set, filesystem names are treated case
 128                                           insensitive. */
 129 #define ROOTBITS_RECYCLED      (64)    /* When set, files being deleted will first be
 130                                           moved to the Recycled directory. */
 131
 132 struct fsExtentBNode {
 133   ULONG be_key;     /* data! */
 134   ULONG be_next;
 135   ULONG be_prev;
 136   UWORD be_blocks;  /* The size in blocks of the region this Extent controls */
 137 } __attribute__((packed));
 138
 139 #endif // _BLOCKSTRUCTURE_H