/********************************************************************/
/** Microsoft LAN Manager **/
/** Copyright(c) Microsoft Corp., 1987-1990 **/
/********************************************************************/
#define SEC_SUPERB 16 /* superblock is after 8K boot block */
#define SEC_SPAREB 17 /* spareblock is after superblock */
#define SEC_BOOT 0 /* boot sector */
#define SUPERB_PWLEN 15
/** SUPERB.INC - Super Block Definition
*
* The Superblock is the first block of the file system.
* It starts at sector #4, leaving 2K for boot sectors.
*
* Pointer to the root directory
* Pointer to the bit map
* Clean pointer
* Pointer to the bad list
*/
struct RSP {
unsigned long P; /* main psector pointer */
unsigned long P2; /* spare pointer */
}; /* RSP */
struct SuperB {
unsigned long SB_SIG1; /* signature value 1 */
unsigned long SB_SIG2; /* signature value 2 */
unsigned char SB_VER; /* version # of filesystem structures */
unsigned char SB_FVER; /* functional version number - the smallest/
* oldest version of the filesystem that can
* understand this disk - some version
* enhancements may define fields which can be
* ignored by earlier versions */
short SB_DUMY; /* free */
unsigned long SB_ROOT; /* Psector # of root fnode */
unsigned long SB_SEC; /* # of sectors on volume */
unsigned long SB_BSEC; /* # of bad sectors on volume */
struct RSP SB_BII; /* Bitmap Indirect Block */
struct RSP SB_BBL; /* badblock list chain #1 */
unsigned long SB_CDDAT; /* date of last CHKDSK */
unsigned long SB_DODAT; /* date of last Disk Optimize */
unsigned long SB_DBSIZE; /* # of sectors in dirblk band */
unsigned long SB_DBLOW; /* first Psector in DIRBLK band */
unsigned long SB_DBHIGH; /* last Psector in DIRBLK band */
unsigned long SB_DBMAP; /* first Psector of DIRBLK band bit map. Starts
* on a 2K boundary, 2K bytes maximum */
unsigned char SB_VOLNAME[32]; /* Volume name */
unsigned long SB_SIDSEC; /* sector # of first sector in SIDTAB */
/* ID map is 4K - 8 contiguous sectors */
unsigned char BlankSpace[512-100];
/* MUST BE ZERO */
}; /* SuperB */
/** SpareB - Spare Block Definitions
*
* SpareB contains various emergency supplies and fixup information.
* This stuff isn't in the superblock in order for the superblock
* to be read only and decrease the liklihood that a flakey write
* will cause the superblock to become unreadable.
*
* This sector is located directly after the superblock - sector 5.
*
* Note that the number of spare DIRBLKs is a format option, given
* that they all have to fit into the SpareB, giving us a max of
* 101 of them.
*
* Access to the SpareB is complicated by the fact that we can't
* access it via the cache, since the cache may be unavailable.
* If every cache buffer is dirty, we could get a HotFix error when
* writing the first one, which would deadlock us if we needed to
* read this stuff via the cache. Instead, we read it directly into
* a private buffer via RdHF.
*
* This means that the disk layout must be such that each cache cluster
* that contains the SpareB or the hotfix list must not contain any
* other writable sector, to prevent us from having a modified
* direct-written sector overwritten by an earlier unmodified copy
* which was in a cache block. It's ok for the SuperB to be in the
* same cache group as the SpareB since the SuperB is RO to the filesys.
*
* Checksums. Done on both Super Block and the Spare Block.
* Both checksums are stored in the Spare Block. The checksum
* field for the Super Block (SPB_SUPERBSUM) must be set when
* calculating the checksum for the Spare Block. The checksum
* field for the Spare Block (SPB_SPAREBSUM) must be zero when
* calculating the checksum for the Spare Block.
* If both checksum fields are zero, the checksums have not been
* calculated for the volume.
*
*/
#define SPAREDB 20 /* 20 spare DIRBLKs */
struct SpareB {
unsigned long SPB_SIG1; /* signature value 1 */
unsigned long SPB_SIG2; /* signature value 2 */
unsigned char SPB_FLAG; /* cleanliness flag */
unsigned char SPB_ALIGN[3]; /* alignment */
unsigned long SPB_HFSEC; /* first hotfix list P sector */
unsigned long SPB_HFUSE; /* # of hot fixes in effect */
unsigned long SPB_HFMAX; /* max size of hot fix list */
unsigned long SPB_SDBCNT; /* # of spare dirblks */
unsigned long SPB_SDBMAX; /* maximum number of spare DB values. */
unsigned long SPB_CPSEC; /* code page sector */
unsigned long SPB_CPCNT; /* count of code pages on volume */
unsigned long SPB_SUPERBSUM; /* Checksum of Super Block */
unsigned long SPB_SPAREBSUM; /* Checksum of Spare Block */
unsigned long SPB_DUMY[15]; /* some extra space for future use */
unsigned long SPB_SPARDB[101]; /* Psector #s of spare dirblks */
}; /* SpareB */
/* Super Block and Spare Block Signatures */
#define SBSIG1 0xf995e849 /* two signatures cause we got lotsa */
#define SBSIG2 0xFA53E9C5 /* space */
#define SPSIG1 0xf9911849 /* two signatures cause we got lotsa */
#define SPSIG2 0xFA5229C5 /* space */
/* Superblock Versions */
#define SBBASEV 2 /* base version */
#define SBBASEFV 2 /* base functional version */
/* Superblock flags */
#define SBF_LOCALSEC 1
/* Spare Block Flags */
#define SPF_DIRT 0x0001 /* file system is dirty */
#define SPF_SPARE 0x0002 /* spare DIRBLKs have been used */
#define SPF_HFUSED 0x0004 /* hot fix sectors have been used */
#define SPF_BADSEC 0x0008 /* bad sector, corrupt disk */
#define SPF_BADBM 0x0010 /* bad bitmap block */
#define SPF_VER 0x0080 /* file system was written by a version
* < SB_VER, so some of the new fields
* may have not been updated */
/** Bit maps
*
* PFS keeps track of free space in a series of bit maps.
* Currently, each bit map is 2048 bytes, which covers about
* 8 megabytes of disk space. We could rearrange these to be
* more cylinder sensitive...
*
* The superblock has the address of a section of contiguous sectors
* that contains a double word sector # for each bit map block. This
* will be a maximum of 2048 bytes (4 sectors)
*
* Max # of size RAM (K) size 2nd lvl
* bitmaps (meg) to reside bitmap
* bitmap (bytes)
*
* 1 8.39 2 256
* 2 16.78 4 512
* 3 25.17 6 768
* 4 33.55 8 1024
* 5 41.94 10 1280
* 6 50.33 12 1536
* 7 58.72 14 1792
* 8 67.11 16 2048
* 9 75.50 18 2304
* 10 83.89 20 2560
* 15 125.83 30 3840
* 20 167.77 40 5120
* 30 251.66 60 7680
* 40 335.54 80 10240
* 50 419.43 100 12800
* 100 838.86 200 25600
* 200 1677.72 400 51200
* 300 2516.58 600 76800
* 400 3355.44 800 102400
* 500 4194.30 1000 128000
*/
/** Hot Fixing
*
* Each file system maintains a structure listing N "hot fix"
* disk clusters of HOTFIXSIZ sectors each, each starting on
* a multiple of HOTFIXSIZ. Whenever the file system discovers
* that it's trying to write to a bad spot on the disk it will
* instead select a free hot fix cluster and write there, instead.
* The substitution will be recorded in the hot fix list, and the
* SBF_SPARE bit will be set. The file system sill describes the
* data as being in the bad old sectors; the disk interface will
* do a mapping between the `believed' location and the true location.
*
* CHKDSK will be run as soon as possible; it will move the
* hot fixed data from the hot fix cluster to somewhere else,
* freeing that hot fix cluster, and adjusting the disk structure
* to point to the new location of the data. As a result, entrys
* on the hot fix list should be transient and few.
*
* The superblock contains the # of the first sector of the hot fix list.
* The list takes the following format, spread across as many sectors
* as necessary:
*
* long oldsec[SB_HFMAX]; sector # of start of bad clusters
* long newsec[SB_HFMAX]; sector # of start of subst. cluster
* long fnode [SB_HFMAX]; fnode sector of file/directory
* involved with bad cluster. May be
* 0 (don't know) or invalid. The
* repair program must verify that it
* *is* an FNODE and must see if other
* structures might also involve this
* bad cluster.
*
* the SB_HFUSE field describes the number of these records which is
* in use - unused ones should have oldsec[i] = 0. The list will
* be 'dense' - no oldsec[i] will be 0 where i < SB_HFUSE.
*
* The sector(s) which contain the hot fix list must be contiguous
* and may not themselves be defective.
*/
