494 lines
17 KiB
C
494 lines
17 KiB
C
/*
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* linux/fs/hpfs/hpfs.h
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*
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* HPFS structures by Chris Smith, 1993
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*
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* a little bit modified by Mikulas Patocka, 1998-1999
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*/
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/* The paper
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Duncan, Roy
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Design goals and implementation of the new High Performance File System
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Microsoft Systems Journal Sept 1989 v4 n5 p1(13)
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describes what HPFS looked like when it was new, and it is the source
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of most of the information given here. The rest is conjecture.
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For definitive information on the Duncan paper, see it, not this file.
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For definitive information on HPFS, ask somebody else -- this is guesswork.
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There are certain to be many mistakes. */
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/* Notation */
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typedef unsigned secno; /* sector number, partition relative */
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typedef secno dnode_secno; /* sector number of a dnode */
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typedef secno fnode_secno; /* sector number of an fnode */
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typedef secno anode_secno; /* sector number of an anode */
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typedef u32 time32_t; /* 32-bit time_t type */
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/* sector 0 */
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/* The boot block is very like a FAT boot block, except that the
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29h signature byte is 28h instead, and the ID string is "HPFS". */
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#define BB_MAGIC 0xaa55
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struct hpfs_boot_block
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{
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unsigned char jmp[3];
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unsigned char oem_id[8];
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unsigned char bytes_per_sector[2]; /* 512 */
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unsigned char sectors_per_cluster;
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unsigned char n_reserved_sectors[2];
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unsigned char n_fats;
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unsigned char n_rootdir_entries[2];
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unsigned char n_sectors_s[2];
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unsigned char media_byte;
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unsigned short sectors_per_fat;
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unsigned short sectors_per_track;
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unsigned short heads_per_cyl;
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unsigned int n_hidden_sectors;
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unsigned int n_sectors_l; /* size of partition */
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unsigned char drive_number;
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unsigned char mbz;
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unsigned char sig_28h; /* 28h */
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unsigned char vol_serno[4];
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unsigned char vol_label[11];
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unsigned char sig_hpfs[8]; /* "HPFS " */
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unsigned char pad[448];
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unsigned short magic; /* aa55 */
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};
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/* sector 16 */
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/* The super block has the pointer to the root directory. */
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#define SB_MAGIC 0xf995e849
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struct hpfs_super_block
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{
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unsigned magic; /* f995 e849 */
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unsigned magic1; /* fa53 e9c5, more magic? */
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/*unsigned huh202;*/ /* ?? 202 = N. of B. in 1.00390625 S.*/
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char version; /* version of a filesystem usually 2 */
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char funcversion; /* functional version - oldest version
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of filesystem that can understand
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this disk */
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unsigned short int zero; /* 0 */
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fnode_secno root; /* fnode of root directory */
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secno n_sectors; /* size of filesystem */
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unsigned n_badblocks; /* number of bad blocks */
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secno bitmaps; /* pointers to free space bit maps */
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unsigned zero1; /* 0 */
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secno badblocks; /* bad block list */
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unsigned zero3; /* 0 */
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time32_t last_chkdsk; /* date last checked, 0 if never */
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/*unsigned zero4;*/ /* 0 */
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time32_t last_optimize; /* date last optimized, 0 if never */
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secno n_dir_band; /* number of sectors in dir band */
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secno dir_band_start; /* first sector in dir band */
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secno dir_band_end; /* last sector in dir band */
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secno dir_band_bitmap; /* free space map, 1 dnode per bit */
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char volume_name[32]; /* not used */
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secno user_id_table; /* 8 preallocated sectors - user id */
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unsigned zero6[103]; /* 0 */
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};
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/* sector 17 */
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/* The spare block has pointers to spare sectors. */
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#define SP_MAGIC 0xf9911849
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struct hpfs_spare_block
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{
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unsigned magic; /* f991 1849 */
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unsigned magic1; /* fa52 29c5, more magic? */
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unsigned dirty: 1; /* 0 clean, 1 "improperly stopped" */
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/*unsigned flag1234: 4;*/ /* unknown flags */
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unsigned sparedir_used: 1; /* spare dirblks used */
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unsigned hotfixes_used: 1; /* hotfixes used */
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unsigned bad_sector: 1; /* bad sector, corrupted disk (???) */
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unsigned bad_bitmap: 1; /* bad bitmap */
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unsigned fast: 1; /* partition was fast formatted */
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unsigned old_wrote: 1; /* old version wrote to partion */
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unsigned old_wrote_1: 1; /* old version wrote to partion (?) */
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unsigned install_dasd_limits: 1; /* HPFS386 flags */
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unsigned resynch_dasd_limits: 1;
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unsigned dasd_limits_operational: 1;
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unsigned multimedia_active: 1;
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unsigned dce_acls_active: 1;
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unsigned dasd_limits_dirty: 1;
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unsigned flag67: 2;
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unsigned char mm_contlgulty;
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unsigned char unused;
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secno hotfix_map; /* info about remapped bad sectors */
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unsigned n_spares_used; /* number of hotfixes */
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unsigned n_spares; /* number of spares in hotfix map */
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unsigned n_dnode_spares_free; /* spare dnodes unused */
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unsigned n_dnode_spares; /* length of spare_dnodes[] list,
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follows in this block*/
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secno code_page_dir; /* code page directory block */
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unsigned n_code_pages; /* number of code pages */
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/*unsigned large_numbers[2];*/ /* ?? */
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unsigned super_crc; /* on HPFS386 and LAN Server this is
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checksum of superblock, on normal
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OS/2 unused */
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unsigned spare_crc; /* on HPFS386 checksum of spareblock */
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unsigned zero1[15]; /* unused */
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dnode_secno spare_dnodes[100]; /* emergency free dnode list */
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unsigned zero2[1]; /* room for more? */
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};
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/* The bad block list is 4 sectors long. The first word must be zero,
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the remaining words give n_badblocks bad block numbers.
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I bet you can see it coming... */
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#define BAD_MAGIC 0
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/* The hotfix map is 4 sectors long. It looks like
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secno from[n_spares];
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secno to[n_spares];
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The to[] list is initialized to point to n_spares preallocated empty
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sectors. The from[] list contains the sector numbers of bad blocks
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which have been remapped to corresponding sectors in the to[] list.
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n_spares_used gives the length of the from[] list. */
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/* Sectors 18 and 19 are preallocated and unused.
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Maybe they're spares for 16 and 17, but simple substitution fails. */
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/* The code page info pointed to by the spare block consists of an index
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block and blocks containing uppercasing tables. I don't know what
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these are for (CHKDSK, maybe?) -- OS/2 does not seem to use them
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itself. Linux doesn't use them either. */
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/* block pointed to by spareblock->code_page_dir */
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#define CP_DIR_MAGIC 0x494521f7
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struct code_page_directory
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{
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unsigned magic; /* 4945 21f7 */
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unsigned n_code_pages; /* number of pointers following */
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unsigned zero1[2];
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struct {
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unsigned short ix; /* index */
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unsigned short code_page_number; /* code page number */
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unsigned bounds; /* matches corresponding word
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in data block */
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secno code_page_data; /* sector number of a code_page_data
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containing c.p. array */
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unsigned short index; /* index in c.p. array in that sector*/
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unsigned short unknown; /* some unknown value; usually 0;
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2 in Japanese version */
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} array[31]; /* unknown length */
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};
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/* blocks pointed to by code_page_directory */
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#define CP_DATA_MAGIC 0x894521f7
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struct code_page_data
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{
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unsigned magic; /* 8945 21f7 */
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unsigned n_used; /* # elements used in c_p_data[] */
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unsigned bounds[3]; /* looks a bit like
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(beg1,end1), (beg2,end2)
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one byte each */
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unsigned short offs[3]; /* offsets from start of sector
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to start of c_p_data[ix] */
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struct {
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unsigned short ix; /* index */
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unsigned short code_page_number; /* code page number */
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unsigned short unknown; /* the same as in cp directory */
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unsigned char map[128]; /* upcase table for chars 80..ff */
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unsigned short zero2;
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} code_page[3];
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unsigned char incognita[78];
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};
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/* Free space bitmaps are 4 sectors long, which is 16384 bits.
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16384 sectors is 8 meg, and each 8 meg band has a 4-sector bitmap.
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Bit order in the maps is little-endian. 0 means taken, 1 means free.
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Bit map sectors are marked allocated in the bit maps, and so are sectors
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off the end of the partition.
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Band 0 is sectors 0-3fff, its map is in sectors 18-1b.
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Band 1 is 4000-7fff, its map is in 7ffc-7fff.
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Band 2 is 8000-ffff, its map is in 8000-8003.
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The remaining bands have maps in their first (even) or last (odd) 4 sectors
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-- if the last, partial, band is odd its map is in its last 4 sectors.
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The bitmap locations are given in a table pointed to by the super block.
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No doubt they aren't constrained to be at 18, 7ffc, 8000, ...; that is
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just where they usually are.
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The "directory band" is a bunch of sectors preallocated for dnodes.
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It has a 4-sector free space bitmap of its own. Each bit in the map
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corresponds to one 4-sector dnode, bit 0 of the map corresponding to
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the first 4 sectors of the directory band. The entire band is marked
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allocated in the main bitmap. The super block gives the locations
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of the directory band and its bitmap. ("band" doesn't mean it is
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8 meg long; it isn't.) */
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/* dnode: directory. 4 sectors long */
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/* A directory is a tree of dnodes. The fnode for a directory
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contains one pointer, to the root dnode of the tree. The fnode
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never moves, the dnodes do the B-tree thing, splitting and merging
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as files are added and removed. */
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#define DNODE_MAGIC 0x77e40aae
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struct dnode {
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unsigned magic; /* 77e4 0aae */
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unsigned first_free; /* offset from start of dnode to
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first free dir entry */
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unsigned root_dnode:1; /* Is it root dnode? */
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unsigned increment_me:31; /* some kind of activity counter?
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Neither HPFS.IFS nor CHKDSK cares
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if you change this word */
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secno up; /* (root dnode) directory's fnode
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(nonroot) parent dnode */
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dnode_secno self; /* pointer to this dnode */
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unsigned char dirent[2028]; /* one or more dirents */
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};
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struct hpfs_dirent {
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unsigned short length; /* offset to next dirent */
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unsigned first: 1; /* set on phony ^A^A (".") entry */
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unsigned has_acl: 1;
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unsigned down: 1; /* down pointer present (after name) */
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unsigned last: 1; /* set on phony \377 entry */
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unsigned has_ea: 1; /* entry has EA */
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unsigned has_xtd_perm: 1; /* has extended perm list (???) */
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unsigned has_explicit_acl: 1;
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unsigned has_needea: 1; /* ?? some EA has NEEDEA set
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I have no idea why this is
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interesting in a dir entry */
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unsigned read_only: 1; /* dos attrib */
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unsigned hidden: 1; /* dos attrib */
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unsigned system: 1; /* dos attrib */
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unsigned flag11: 1; /* would be volume label dos attrib */
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unsigned directory: 1; /* dos attrib */
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unsigned archive: 1; /* dos attrib */
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unsigned not_8x3: 1; /* name is not 8.3 */
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unsigned flag15: 1;
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fnode_secno fnode; /* fnode giving allocation info */
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time32_t write_date; /* mtime */
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unsigned file_size; /* file length, bytes */
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time32_t read_date; /* atime */
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time32_t creation_date; /* ctime */
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unsigned ea_size; /* total EA length, bytes */
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unsigned char no_of_acls : 3; /* number of ACL's */
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unsigned char reserver : 5;
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unsigned char ix; /* code page index (of filename), see
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struct code_page_data */
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unsigned char namelen, name[1]; /* file name */
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/* dnode_secno down; btree down pointer, if present,
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follows name on next word boundary, or maybe it
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precedes next dirent, which is on a word boundary. */
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};
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/* B+ tree: allocation info in fnodes and anodes */
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/* dnodes point to fnodes which are responsible for listing the sectors
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assigned to the file. This is done with trees of (length,address)
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pairs. (Actually triples, of (length, file-address, disk-address)
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which can represent holes. Find out if HPFS does that.)
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At any rate, fnodes contain a small tree; if subtrees are needed
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they occupy essentially a full block in anodes. A leaf-level tree node
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has 3-word entries giving sector runs, a non-leaf node has 2-word
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entries giving subtree pointers. A flag in the header says which. */
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struct bplus_leaf_node
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{
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unsigned file_secno; /* first file sector in extent */
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unsigned length; /* length, sectors */
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secno disk_secno; /* first corresponding disk sector */
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};
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struct bplus_internal_node
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{
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unsigned file_secno; /* subtree maps sectors < this */
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anode_secno down; /* pointer to subtree */
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};
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struct bplus_header
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{
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unsigned hbff: 1; /* high bit of first free entry offset */
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unsigned flag1: 1;
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unsigned flag2: 1;
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unsigned flag3: 1;
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unsigned flag4: 1;
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unsigned fnode_parent: 1; /* ? we're pointed to by an fnode,
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the data btree or some ea or the
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main ea bootage pointer ea_secno */
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/* also can get set in fnodes, which
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may be a chkdsk glitch or may mean
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this bit is irrelevant in fnodes,
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or this interpretation is all wet */
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unsigned binary_search: 1; /* suggest binary search (unused) */
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unsigned internal: 1; /* 1 -> (internal) tree of anodes
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0 -> (leaf) list of extents */
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unsigned char fill[3];
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unsigned char n_free_nodes; /* free nodes in following array */
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unsigned char n_used_nodes; /* used nodes in following array */
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unsigned short first_free; /* offset from start of header to
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first free node in array */
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union {
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struct bplus_internal_node internal[0]; /* (internal) 2-word entries giving
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subtree pointers */
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struct bplus_leaf_node external[0]; /* (external) 3-word entries giving
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sector runs */
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} u;
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};
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/* fnode: root of allocation b+ tree, and EA's */
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/* Every file and every directory has one fnode, pointed to by the directory
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entry and pointing to the file's sectors or directory's root dnode. EA's
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are also stored here, and there are said to be ACL's somewhere here too. */
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#define FNODE_MAGIC 0xf7e40aae
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struct fnode
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{
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unsigned magic; /* f7e4 0aae */
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unsigned zero1[2]; /* read history */
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unsigned char len, name[15]; /* true length, truncated name */
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fnode_secno up; /* pointer to file's directory fnode */
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/*unsigned zero2[3];*/
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secno acl_size_l;
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secno acl_secno;
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unsigned short acl_size_s;
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char acl_anode;
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char zero2; /* history bit count */
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unsigned ea_size_l; /* length of disk-resident ea's */
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secno ea_secno; /* first sector of disk-resident ea's*/
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unsigned short ea_size_s; /* length of fnode-resident ea's */
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unsigned flag0: 1;
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unsigned ea_anode: 1; /* 1 -> ea_secno is an anode */
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unsigned flag2: 1;
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unsigned flag3: 1;
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unsigned flag4: 1;
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unsigned flag5: 1;
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unsigned flag6: 1;
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unsigned flag7: 1;
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unsigned dirflag: 1; /* 1 -> directory. first & only extent
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points to dnode. */
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unsigned flag9: 1;
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unsigned flag10: 1;
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unsigned flag11: 1;
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unsigned flag12: 1;
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unsigned flag13: 1;
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unsigned flag14: 1;
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unsigned flag15: 1;
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struct bplus_header btree; /* b+ tree, 8 extents or 12 subtrees */
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union {
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struct bplus_leaf_node external[8];
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struct bplus_internal_node internal[12];
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} u;
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unsigned file_size; /* file length, bytes */
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unsigned n_needea; /* number of EA's with NEEDEA set */
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char user_id[16]; /* unused */
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unsigned short ea_offs; /* offset from start of fnode
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to first fnode-resident ea */
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char dasd_limit_treshhold;
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char dasd_limit_delta;
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unsigned dasd_limit;
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unsigned dasd_usage;
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/*unsigned zero5[2];*/
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unsigned char ea[316]; /* zero or more EA's, packed together
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with no alignment padding.
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(Do not use this name, get here
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via fnode + ea_offs. I think.) */
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};
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/* anode: 99.44% pure allocation tree */
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#define ANODE_MAGIC 0x37e40aae
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struct anode
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{
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unsigned magic; /* 37e4 0aae */
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anode_secno self; /* pointer to this anode */
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secno up; /* parent anode or fnode */
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struct bplus_header btree; /* b+tree, 40 extents or 60 subtrees */
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union {
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struct bplus_leaf_node external[40];
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struct bplus_internal_node internal[60];
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} u;
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unsigned fill[3]; /* unused */
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};
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/* extended attributes.
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A file's EA info is stored as a list of (name,value) pairs. It is
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usually in the fnode, but (if it's large) it is moved to a single
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sector run outside the fnode, or to multiple runs with an anode tree
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that points to them.
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The value of a single EA is stored along with the name, or (if large)
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it is moved to a single sector run, or multiple runs pointed to by an
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anode tree, pointed to by the value field of the (name,value) pair.
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Flags in the EA tell whether the value is immediate, in a single sector
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run, or in multiple runs. Flags in the fnode tell whether the EA list
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is immediate, in a single run, or in multiple runs. */
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struct extended_attribute
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{
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unsigned indirect: 1; /* 1 -> value gives sector number
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where real value starts */
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unsigned anode: 1; /* 1 -> sector is an anode
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that points to fragmented value */
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unsigned flag2: 1;
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unsigned flag3: 1;
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unsigned flag4: 1;
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unsigned flag5: 1;
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unsigned flag6: 1;
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unsigned needea: 1; /* required ea */
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unsigned char namelen; /* length of name, bytes */
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unsigned short valuelen; /* length of value, bytes */
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unsigned char name[0];
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/*
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unsigned char name[namelen]; ascii attrib name
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unsigned char nul; terminating '\0', not counted
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unsigned char value[valuelen]; value, arbitrary
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if this.indirect, valuelen is 8 and the value is
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unsigned length; real length of value, bytes
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secno secno; sector address where it starts
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if this.anode, the above sector number is the root of an anode tree
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which points to the value.
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*/
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};
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/*
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Local Variables:
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comment-column: 40
|
|
End:
|
|
*/
|