fs/hpfs/hpfs.h

   1 /*
   2  *  linux/fs/hpfs/hpfs.h
   3  *
   4  *  HPFS structures by Chris Smith, 1993
   5  *
   6  *  a little bit modified by Mikulas Patocka, 1998-1999
   7  */
   8
   9 /* The paper
  10
  11      Duncan, Roy
  12      Design goals and implementation of the new High Performance File System
  13      Microsoft Systems Journal  Sept 1989  v4 n5 p1(13)
  14
  15    describes what HPFS looked like when it was new, and it is the source
  16    of most of the information given here.  The rest is conjecture.
  17
  18    For definitive information on the Duncan paper, see it, not this file.
  19    For definitive information on HPFS, ask somebody else -- this is guesswork.
  20    There are certain to be many mistakes. */
  21
  22 /* Notation */
  23
  24 typedef unsigned secno;                 /* sector number, partition relative */
  25
  26 typedef secno dnode_secno;              /* sector number of a dnode */
  27 typedef secno fnode_secno;              /* sector number of an fnode */
  28 typedef secno anode_secno;              /* sector number of an anode */
  29
  30 typedef u32 time32_t;           /* 32-bit time_t type */
  31
  32 /* sector 0 */
  33
  34 /* The boot block is very like a FAT boot block, except that the
  35    29h signature byte is 28h instead, and the ID string is "HPFS". */
  36
  37 #define BB_MAGIC 0xaa55
  38
  39 struct hpfs_boot_block
  40 {
  41   unsigned char jmp[3];
  42   unsigned char oem_id[8];
  43   unsigned char bytes_per_sector[2];    /* 512 */
  44   unsigned char sectors_per_cluster;
  45   unsigned char n_reserved_sectors[2];
  46   unsigned char n_fats;
  47   unsigned char n_rootdir_entries[2];
  48   unsigned char n_sectors_s[2];
  49   unsigned char media_byte;
  50   unsigned short sectors_per_fat;
  51   unsigned short sectors_per_track;
  52   unsigned short heads_per_cyl;
  53   unsigned int n_hidden_sectors;
  54   unsigned int n_sectors_l;             /* size of partition */
  55   unsigned char drive_number;
  56   unsigned char mbz;
  57   unsigned char sig_28h;                /* 28h */
  58   unsigned char vol_serno[4];
  59   unsigned char vol_label[11];
  60   unsigned char sig_hpfs[8];            /* "HPFS    " */
  61   unsigned char pad[448];
  62   unsigned short magic;                 /* aa55 */
  63 };
  64
  65
  66 /* sector 16 */
  67
  68 /* The super block has the pointer to the root directory. */
  69
  70 #define SB_MAGIC 0xf995e849
  71
  72 struct hpfs_super_block
  73 {
  74   unsigned magic;                       /* f995 e849 */
  75   unsigned magic1;                      /* fa53 e9c5, more magic? */
  76   /*unsigned huh202;*/                  /* ?? 202 = N. of B. in 1.00390625 S.*/
  77   char version;                         /* version of a filesystem  usually 2 */
  78   char funcversion;                     /* functional version - oldest version
  79                                            of filesystem that can understand
  80                                            this disk */
  81   unsigned short int zero;              /* 0 */
  82   fnode_secno root;                     /* fnode of root directory */
  83   secno n_sectors;                      /* size of filesystem */
  84   unsigned n_badblocks;                 /* number of bad blocks */
  85   secno bitmaps;                        /* pointers to free space bit maps */
  86   unsigned zero1;                       /* 0 */
  87   secno badblocks;                      /* bad block list */
  88   unsigned zero3;                       /* 0 */
  89   time32_t last_chkdsk;                 /* date last checked, 0 if never */
  90   /*unsigned zero4;*/                   /* 0 */
  91   time32_t last_optimize;                       /* date last optimized, 0 if never */
  92   secno n_dir_band;                     /* number of sectors in dir band */
  93   secno dir_band_start;                 /* first sector in dir band */
  94   secno dir_band_end;                   /* last sector in dir band */
  95   secno dir_band_bitmap;                /* free space map, 1 dnode per bit */
  96   char volume_name[32];                 /* not used */
  97   secno user_id_table;                  /* 8 preallocated sectors - user id */
  98   unsigned zero6[103];                  /* 0 */
  99 };
 100
 101
 102 /* sector 17 */
 103
 104 /* The spare block has pointers to spare sectors.  */
 105
 106 #define SP_MAGIC 0xf9911849
 107
 108 struct hpfs_spare_block
 109 {
 110   unsigned magic;                       /* f991 1849 */
 111   unsigned magic1;                      /* fa52 29c5, more magic? */
 112
 113   unsigned dirty: 1;                    /* 0 clean, 1 "improperly stopped" */
 114   /*unsigned flag1234: 4;*/             /* unknown flags */
 115   unsigned sparedir_used: 1;            /* spare dirblks used */
 116   unsigned hotfixes_used: 1;            /* hotfixes used */
 117   unsigned bad_sector: 1;               /* bad sector, corrupted disk (???) */
 118   unsigned bad_bitmap: 1;               /* bad bitmap */
 119   unsigned fast: 1;                     /* partition was fast formatted */
 120   unsigned old_wrote: 1;                /* old version wrote to partion */
 121   unsigned old_wrote_1: 1;              /* old version wrote to partion (?) */
 122   unsigned install_dasd_limits: 1;      /* HPFS386 flags */
 123   unsigned resynch_dasd_limits: 1;
 124   unsigned dasd_limits_operational: 1;
 125   unsigned multimedia_active: 1;
 126   unsigned dce_acls_active: 1;
 127   unsigned dasd_limits_dirty: 1;
 128   unsigned flag67: 2;
 129   unsigned char mm_contlgulty;
 130   unsigned char unused;
 131
 132   secno hotfix_map;                     /* info about remapped bad sectors */
 133   unsigned n_spares_used;               /* number of hotfixes */
 134   unsigned n_spares;                    /* number of spares in hotfix map */
 135   unsigned n_dnode_spares_free;         /* spare dnodes unused */
 136   unsigned n_dnode_spares;              /* length of spare_dnodes[] list,
 137                                            follows in this block*/
 138   secno code_page_dir;                  /* code page directory block */
 139   unsigned n_code_pages;                /* number of code pages */
 140   /*unsigned large_numbers[2];*/        /* ?? */
 141   unsigned super_crc;                   /* on HPFS386 and LAN Server this is
 142                                            checksum of superblock, on normal
 143                                            OS/2 unused */
 144   unsigned spare_crc;                   /* on HPFS386 checksum of spareblock */
 145   unsigned zero1[15];                   /* unused */
 146   dnode_secno spare_dnodes[100];        /* emergency free dnode list */
 147   unsigned zero2[1];                    /* room for more? */
 148 };
 149
 150 /* The bad block list is 4 sectors long.  The first word must be zero,
 151    the remaining words give n_badblocks bad block numbers.
 152    I bet you can see it coming... */
 153
 154 #define BAD_MAGIC 0
 155
 156 /* The hotfix map is 4 sectors long.  It looks like
 157
 158        secno from[n_spares];
 159        secno to[n_spares];
 160
 161    The to[] list is initialized to point to n_spares preallocated empty
 162    sectors.  The from[] list contains the sector numbers of bad blocks
 163    which have been remapped to corresponding sectors in the to[] list.
 164    n_spares_used gives the length of the from[] list. */
 165
 166
 167 /* Sectors 18 and 19 are preallocated and unused.
 168    Maybe they're spares for 16 and 17, but simple substitution fails. */
 169
 170
 171 /* The code page info pointed to by the spare block consists of an index
 172    block and blocks containing uppercasing tables.  I don't know what
 173    these are for (CHKDSK, maybe?) -- OS/2 does not seem to use them
 174    itself.  Linux doesn't use them either. */
 175
 176 /* block pointed to by spareblock->code_page_dir */
 177
 178 #define CP_DIR_MAGIC 0x494521f7
 179
 180 struct code_page_directory
 181 {
 182   unsigned magic;                       /* 4945 21f7 */
 183   unsigned n_code_pages;                /* number of pointers following */
 184   unsigned zero1[2];
 185   struct {
 186     unsigned short ix;                  /* index */
 187     unsigned short code_page_number;    /* code page number */
 188     unsigned bounds;                    /* matches corresponding word
 189                                            in data block */
 190     secno code_page_data;               /* sector number of a code_page_data
 191                                            containing c.p. array */
 192     unsigned short index;               /* index in c.p. array in that sector*/
 193     unsigned short unknown;             /* some unknown value; usually 0;
 194                                            2 in Japanese version */
 195   } array[31];                          /* unknown length */
 196 };
 197
 198 /* blocks pointed to by code_page_directory */
 199
 200 #define CP_DATA_MAGIC 0x894521f7
 201
 202 struct code_page_data
 203 {
 204   unsigned magic;                       /* 8945 21f7 */
 205   unsigned n_used;                      /* # elements used in c_p_data[] */
 206   unsigned bounds[3];                   /* looks a bit like
 207                                              (beg1,end1), (beg2,end2)
 208                                            one byte each */
 209   unsigned short offs[3];               /* offsets from start of sector
 210                                            to start of c_p_data[ix] */
 211   struct {
 212     unsigned short ix;                  /* index */
 213     unsigned short code_page_number;    /* code page number */
 214     unsigned short unknown;             /* the same as in cp directory */
 215     unsigned char map[128];             /* upcase table for chars 80..ff */
 216     unsigned short zero2;
 217   } code_page[3];
 218   unsigned char incognita[78];
 219 };
 220
 221
 222 /* Free space bitmaps are 4 sectors long, which is 16384 bits.
 223    16384 sectors is 8 meg, and each 8 meg band has a 4-sector bitmap.
 224    Bit order in the maps is little-endian.  0 means taken, 1 means free.
 225
 226    Bit map sectors are marked allocated in the bit maps, and so are sectors
 227    off the end of the partition.
 228
 229    Band 0 is sectors 0-3fff, its map is in sectors 18-1b.
 230    Band 1 is 4000-7fff, its map is in 7ffc-7fff.
 231    Band 2 is 8000-ffff, its map is in 8000-8003.
 232    The remaining bands have maps in their first (even) or last (odd) 4 sectors
 233      -- if the last, partial, band is odd its map is in its last 4 sectors.
 234
 235    The bitmap locations are given in a table pointed to by the super block.
 236    No doubt they aren't constrained to be at 18, 7ffc, 8000, ...; that is
 237    just where they usually are.
 238
 239    The "directory band" is a bunch of sectors preallocated for dnodes.
 240    It has a 4-sector free space bitmap of its own.  Each bit in the map
 241    corresponds to one 4-sector dnode, bit 0 of the map corresponding to
 242    the first 4 sectors of the directory band.  The entire band is marked
 243    allocated in the main bitmap.   The super block gives the locations
 244    of the directory band and its bitmap.  ("band" doesn't mean it is
 245    8 meg long; it isn't.)  */
 246
 247
 248 /* dnode: directory.  4 sectors long */
 249
 250 /* A directory is a tree of dnodes.  The fnode for a directory
 251    contains one pointer, to the root dnode of the tree.  The fnode
 252    never moves, the dnodes do the B-tree thing, splitting and merging
 253    as files are added and removed.  */
 254
 255 #define DNODE_MAGIC   0x77e40aae
 256
 257 struct dnode {
 258   unsigned magic;                       /* 77e4 0aae */
 259   unsigned first_free;                  /* offset from start of dnode to
 260                                            first free dir entry */
 261   unsigned root_dnode:1;                /* Is it root dnode? */
 262   unsigned increment_me:31;             /* some kind of activity counter?
 263                                            Neither HPFS.IFS nor CHKDSK cares
 264                                            if you change this word */
 265   secno up;                             /* (root dnode) directory's fnode
 266                                            (nonroot) parent dnode */
 267   dnode_secno self;                     /* pointer to this dnode */
 268   unsigned char dirent[2028];           /* one or more dirents */
 269 };
 270
 271 struct hpfs_dirent {
 272   unsigned short length;                /* offset to next dirent */
 273   unsigned first: 1;                    /* set on phony ^A^A (".") entry */
 274   unsigned has_acl: 1;
 275   unsigned down: 1;                     /* down pointer present (after name) */
 276   unsigned last: 1;                     /* set on phony \377 entry */
 277   unsigned has_ea: 1;                   /* entry has EA */
 278   unsigned has_xtd_perm: 1;             /* has extended perm list (???) */
 279   unsigned has_explicit_acl: 1;
 280   unsigned has_needea: 1;               /* ?? some EA has NEEDEA set
 281                                            I have no idea why this is
 282                                            interesting in a dir entry */
 283   unsigned read_only: 1;                /* dos attrib */
 284   unsigned hidden: 1;                   /* dos attrib */
 285   unsigned system: 1;                   /* dos attrib */
 286   unsigned flag11: 1;                   /* would be volume label dos attrib */
 287   unsigned directory: 1;                /* dos attrib */
 288   unsigned archive: 1;                  /* dos attrib */
 289   unsigned not_8x3: 1;                  /* name is not 8.3 */
 290   unsigned flag15: 1;
 291   fnode_secno fnode;                    /* fnode giving allocation info */
 292   time32_t write_date;                  /* mtime */
 293   unsigned file_size;                   /* file length, bytes */
 294   time32_t read_date;                   /* atime */
 295   time32_t creation_date;                       /* ctime */
 296   unsigned ea_size;                     /* total EA length, bytes */
 297   unsigned char no_of_acls : 3;         /* number of ACL's */
 298   unsigned char reserver : 5;
 299   unsigned char ix;                     /* code page index (of filename), see
 300                                            struct code_page_data */
 301   unsigned char namelen, name[1];       /* file name */
 302   /* dnode_secno down;    btree down pointer, if present,
 303                           follows name on next word boundary, or maybe it
 304                           precedes next dirent, which is on a word boundary. */
 305 };
 306
 307
 308 /* B+ tree: allocation info in fnodes and anodes */
 309
 310 /* dnodes point to fnodes which are responsible for listing the sectors
 311    assigned to the file.  This is done with trees of (length,address)
 312    pairs.  (Actually triples, of (length, file-address, disk-address)
 313    which can represent holes.  Find out if HPFS does that.)
 314    At any rate, fnodes contain a small tree; if subtrees are needed
 315    they occupy essentially a full block in anodes.  A leaf-level tree node
 316    has 3-word entries giving sector runs, a non-leaf node has 2-word
 317    entries giving subtree pointers.  A flag in the header says which. */
 318
 319 struct bplus_leaf_node
 320 {
 321   unsigned file_secno;                  /* first file sector in extent */
 322   unsigned length;                      /* length, sectors */
 323   secno disk_secno;                     /* first corresponding disk sector */
 324 };
 325
 326 struct bplus_internal_node
 327 {
 328   unsigned file_secno;                  /* subtree maps sectors < this  */
 329   anode_secno down;                     /* pointer to subtree */
 330 };
 331
 332 struct bplus_header
 333 {
 334   unsigned hbff: 1;     /* high bit of first free entry offset */
 335   unsigned flag1: 1;
 336   unsigned flag2: 1;
 337   unsigned flag3: 1;
 338   unsigned flag4: 1;
 339   unsigned fnode_parent: 1;             /* ? we're pointed to by an fnode,
 340                                            the data btree or some ea or the
 341                                            main ea bootage pointer ea_secno */
 342                                         /* also can get set in fnodes, which
 343                                            may be a chkdsk glitch or may mean
 344                                            this bit is irrelevant in fnodes,
 345                                            or this interpretation is all wet */
 346   unsigned binary_search: 1;            /* suggest binary search (unused) */
 347   unsigned internal: 1;                 /* 1 -> (internal) tree of anodes
 348                                            0 -> (leaf) list of extents */
 349   unsigned char fill[3];
 350   unsigned char n_free_nodes;           /* free nodes in following array */
 351   unsigned char n_used_nodes;           /* used nodes in following array */
 352   unsigned short first_free;            /* offset from start of header to
 353                                            first free node in array */
 354   union {
 355     struct bplus_internal_node internal[0]; /* (internal) 2-word entries giving
 356                                                subtree pointers */
 357     struct bplus_leaf_node external[0];     /* (external) 3-word entries giving
 358                                                sector runs */
 359   } u;
 360 };
 361
 362 /* fnode: root of allocation b+ tree, and EA's */
 363
 364 /* Every file and every directory has one fnode, pointed to by the directory
 365    entry and pointing to the file's sectors or directory's root dnode.  EA's
 366    are also stored here, and there are said to be ACL's somewhere here too. */
 367
 368 #define FNODE_MAGIC 0xf7e40aae
 369
 370 struct fnode
 371 {
 372   unsigned magic;                       /* f7e4 0aae */
 373   unsigned zero1[2];                    /* read history */
 374   unsigned char len, name[15];          /* true length, truncated name */
 375   fnode_secno up;                       /* pointer to file's directory fnode */
 376   /*unsigned zero2[3];*/
 377   secno acl_size_l;
 378   secno acl_secno;
 379   unsigned short acl_size_s;
 380   char acl_anode;
 381   char zero2;                           /* history bit count */
 382   unsigned ea_size_l;                   /* length of disk-resident ea's */
 383   secno ea_secno;                       /* first sector of disk-resident ea's*/
 384   unsigned short ea_size_s;             /* length of fnode-resident ea's */
 385
 386   unsigned flag0: 1;
 387   unsigned ea_anode: 1;                 /* 1 -> ea_secno is an anode */
 388   unsigned flag2: 1;
 389   unsigned flag3: 1;
 390   unsigned flag4: 1;
 391   unsigned flag5: 1;
 392   unsigned flag6: 1;
 393   unsigned flag7: 1;
 394   unsigned dirflag: 1;                  /* 1 -> directory.  first & only extent
 395                                            points to dnode. */
 396   unsigned flag9: 1;
 397   unsigned flag10: 1;
 398   unsigned flag11: 1;
 399   unsigned flag12: 1;
 400   unsigned flag13: 1;
 401   unsigned flag14: 1;
 402   unsigned flag15: 1;
 403
 404   struct bplus_header btree;            /* b+ tree, 8 extents or 12 subtrees */
 405   union {
 406     struct bplus_leaf_node external[8];
 407     struct bplus_internal_node internal[12];
 408   } u;
 409
 410   unsigned file_size;                   /* file length, bytes */
 411   unsigned n_needea;                    /* number of EA's with NEEDEA set */
 412   char user_id[16];                     /* unused */
 413   unsigned short ea_offs;               /* offset from start of fnode
 414                                            to first fnode-resident ea */
 415   char dasd_limit_treshhold;
 416   char dasd_limit_delta;
 417   unsigned dasd_limit;
 418   unsigned dasd_usage;
 419   /*unsigned zero5[2];*/
 420   unsigned char ea[316];                /* zero or more EA's, packed together
 421                                            with no alignment padding.
 422                                            (Do not use this name, get here
 423                                            via fnode + ea_offs. I think.) */
 424 };
 425
 426
 427 /* anode: 99.44% pure allocation tree */
 428
 429 #define ANODE_MAGIC 0x37e40aae
 430
 431 struct anode
 432 {
 433   unsigned magic;                       /* 37e4 0aae */
 434   anode_secno self;                     /* pointer to this anode */
 435   secno up;                             /* parent anode or fnode */
 436
 437   struct bplus_header btree;            /* b+tree, 40 extents or 60 subtrees */
 438   union {
 439     struct bplus_leaf_node external[40];
 440     struct bplus_internal_node internal[60];
 441   } u;
 442
 443   unsigned fill[3];                     /* unused */
 444 };
 445
 446
 447 /* extended attributes.
 448
 449    A file's EA info is stored as a list of (name,value) pairs.  It is
 450    usually in the fnode, but (if it's large) it is moved to a single
 451    sector run outside the fnode, or to multiple runs with an anode tree
 452    that points to them.
 453
 454    The value of a single EA is stored along with the name, or (if large)
 455    it is moved to a single sector run, or multiple runs pointed to by an
 456    anode tree, pointed to by the value field of the (name,value) pair.
 457
 458    Flags in the EA tell whether the value is immediate, in a single sector
 459    run, or in multiple runs.  Flags in the fnode tell whether the EA list
 460    is immediate, in a single run, or in multiple runs. */
 461
 462 struct extended_attribute
 463 {
 464   unsigned indirect: 1;                 /* 1 -> value gives sector number
 465                                            where real value starts */
 466   unsigned anode: 1;                    /* 1 -> sector is an anode
 467                                            that points to fragmented value */
 468   unsigned flag2: 1;
 469   unsigned flag3: 1;
 470   unsigned flag4: 1;
 471   unsigned flag5: 1;
 472   unsigned flag6: 1;
 473   unsigned needea: 1;                   /* required ea */
 474   unsigned char namelen;                /* length of name, bytes */
 475   unsigned short valuelen;              /* length of value, bytes */
 476   unsigned char name[0];
 477   /*
 478     unsigned char name[namelen];        ascii attrib name
 479     unsigned char nul;                  terminating '\0', not counted
 480     unsigned char value[valuelen];      value, arbitrary
 481       if this.indirect, valuelen is 8 and the value is
 482         unsigned length;                real length of value, bytes
 483         secno secno;                    sector address where it starts
 484       if this.anode, the above sector number is the root of an anode tree
 485         which points to the value.
 486   */
 487 };
 488
 489 /*
 490    Local Variables:
 491    comment-column: 40
 492    End:
 493 */