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 #if !defined(__LITTLE_ENDIAN) && !defined(__BIG_ENDIAN)
  23 #error unknown endian
  24 #endif
  25
  26 /* Notation */
  27
  28 typedef u32 secno;                      /* sector number, partition relative */
  29
  30 typedef secno dnode_secno;              /* sector number of a dnode */
  31 typedef secno fnode_secno;              /* sector number of an fnode */
  32 typedef secno anode_secno;              /* sector number of an anode */
  33
  34 typedef u32 time32_t;           /* 32-bit time_t type */
  35
  36 /* sector 0 */
  37
  38 /* The boot block is very like a FAT boot block, except that the
  39    29h signature byte is 28h instead, and the ID string is "HPFS". */
  40
  41 #define BB_MAGIC 0xaa55
  42
  43 struct hpfs_boot_block
  44 {
  45   u8 jmp[3];
  46   u8 oem_id[8];
  47   u8 bytes_per_sector[2];       /* 512 */
  48   u8 sectors_per_cluster;
  49   u8 n_reserved_sectors[2];
  50   u8 n_fats;
  51   u8 n_rootdir_entries[2];
  52   u8 n_sectors_s[2];
  53   u8 media_byte;
  54   u16 sectors_per_fat;
  55   u16 sectors_per_track;
  56   u16 heads_per_cyl;
  57   u32 n_hidden_sectors;
  58   u32 n_sectors_l;              /* size of partition */
  59   u8 drive_number;
  60   u8 mbz;
  61   u8 sig_28h;                   /* 28h */
  62   u8 vol_serno[4];
  63   u8 vol_label[11];
  64   u8 sig_hpfs[8];               /* "HPFS    " */
  65   u8 pad[448];
  66   u16 magic;                    /* aa55 */
  67 };
  68
  69
  70 /* sector 16 */
  71
  72 /* The super block has the pointer to the root directory. */
  73
  74 #define SB_MAGIC 0xf995e849
  75
  76 struct hpfs_super_block
  77 {
  78   u32 magic;                            /* f995 e849 */
  79   u32 magic1;                           /* fa53 e9c5, more magic? */
  80   u8 version;                           /* version of a filesystem  usually 2 */
  81   u8 funcversion;                       /* functional version - oldest version
  82                                            of filesystem that can understand
  83                                            this disk */
  84   u16 zero;                             /* 0 */
  85   fnode_secno root;                     /* fnode of root directory */
  86   secno n_sectors;                      /* size of filesystem */
  87   u32 n_badblocks;                      /* number of bad blocks */
  88   secno bitmaps;                        /* pointers to free space bit maps */
  89   u32 zero1;                            /* 0 */
  90   secno badblocks;                      /* bad block list */
  91   u32 zero3;                            /* 0 */
  92   time32_t last_chkdsk;                 /* date last checked, 0 if never */
  93   time32_t last_optimize;               /* date last optimized, 0 if never */
  94   secno n_dir_band;                     /* number of sectors in dir band */
  95   secno dir_band_start;                 /* first sector in dir band */
  96   secno dir_band_end;                   /* last sector in dir band */
  97   secno dir_band_bitmap;                /* free space map, 1 dnode per bit */
  98   u8 volume_name[32];                   /* not used */
  99   secno user_id_table;                  /* 8 preallocated sectors - user id */
 100   u32 zero6[103];                       /* 0 */
 101 };
 102
 103
 104 /* sector 17 */
 105
 106 /* The spare block has pointers to spare sectors.  */
 107
 108 #define SP_MAGIC 0xf9911849
 109
 110 struct hpfs_spare_block
 111 {
 112   u32 magic;                            /* f991 1849 */
 113   u32 magic1;                           /* fa52 29c5, more magic? */
 114
 115 #ifdef __LITTLE_ENDIAN
 116   u8 dirty: 1;                          /* 0 clean, 1 "improperly stopped" */
 117   u8 sparedir_used: 1;                  /* spare dirblks used */
 118   u8 hotfixes_used: 1;                  /* hotfixes used */
 119   u8 bad_sector: 1;                     /* bad sector, corrupted disk (???) */
 120   u8 bad_bitmap: 1;                     /* bad bitmap */
 121   u8 fast: 1;                           /* partition was fast formatted */
 122   u8 old_wrote: 1;                      /* old version wrote to partion */
 123   u8 old_wrote_1: 1;                    /* old version wrote to partion (?) */
 124 #else
 125   u8 old_wrote_1: 1;                    /* old version wrote to partion (?) */
 126   u8 old_wrote: 1;                      /* old version wrote to partion */
 127   u8 fast: 1;                           /* partition was fast formatted */
 128   u8 bad_bitmap: 1;                     /* bad bitmap */
 129   u8 bad_sector: 1;                     /* bad sector, corrupted disk (???) */
 130   u8 hotfixes_used: 1;                  /* hotfixes used */
 131   u8 sparedir_used: 1;                  /* spare dirblks used */
 132   u8 dirty: 1;                          /* 0 clean, 1 "improperly stopped" */
 133 #endif
 134
 135 #ifdef __LITTLE_ENDIAN
 136   u8 install_dasd_limits: 1;            /* HPFS386 flags */
 137   u8 resynch_dasd_limits: 1;
 138   u8 dasd_limits_operational: 1;
 139   u8 multimedia_active: 1;
 140   u8 dce_acls_active: 1;
 141   u8 dasd_limits_dirty: 1;
 142   u8 flag67: 2;
 143 #else
 144   u8 flag67: 2;
 145   u8 dasd_limits_dirty: 1;
 146   u8 dce_acls_active: 1;
 147   u8 multimedia_active: 1;
 148   u8 dasd_limits_operational: 1;
 149   u8 resynch_dasd_limits: 1;
 150   u8 install_dasd_limits: 1;            /* HPFS386 flags */
 151 #endif
 152
 153   u8 mm_contlgulty;
 154   u8 unused;
 155
 156   secno hotfix_map;                     /* info about remapped bad sectors */
 157   u32 n_spares_used;                    /* number of hotfixes */
 158   u32 n_spares;                         /* number of spares in hotfix map */
 159   u32 n_dnode_spares_free;              /* spare dnodes unused */
 160   u32 n_dnode_spares;                   /* length of spare_dnodes[] list,
 161                                            follows in this block*/
 162   secno code_page_dir;                  /* code page directory block */
 163   u32 n_code_pages;                     /* number of code pages */
 164   u32 super_crc;                        /* on HPFS386 and LAN Server this is
 165                                            checksum of superblock, on normal
 166                                            OS/2 unused */
 167   u32 spare_crc;                        /* on HPFS386 checksum of spareblock */
 168   u32 zero1[15];                        /* unused */
 169   dnode_secno spare_dnodes[100];        /* emergency free dnode list */
 170   u32 zero2[1];                         /* room for more? */
 171 };
 172
 173 /* The bad block list is 4 sectors long.  The first word must be zero,
 174    the remaining words give n_badblocks bad block numbers.
 175    I bet you can see it coming... */
 176
 177 #define BAD_MAGIC 0
 178
 179 /* The hotfix map is 4 sectors long.  It looks like
 180
 181        secno from[n_spares];
 182        secno to[n_spares];
 183
 184    The to[] list is initialized to point to n_spares preallocated empty
 185    sectors.  The from[] list contains the sector numbers of bad blocks
 186    which have been remapped to corresponding sectors in the to[] list.
 187    n_spares_used gives the length of the from[] list. */
 188
 189
 190 /* Sectors 18 and 19 are preallocated and unused.
 191    Maybe they're spares for 16 and 17, but simple substitution fails. */
 192
 193
 194 /* The code page info pointed to by the spare block consists of an index
 195    block and blocks containing uppercasing tables.  I don't know what
 196    these are for (CHKDSK, maybe?) -- OS/2 does not seem to use them
 197    itself.  Linux doesn't use them either. */
 198
 199 /* block pointed to by spareblock->code_page_dir */
 200
 201 #define CP_DIR_MAGIC 0x494521f7
 202
 203 struct code_page_directory
 204 {
 205   u32 magic;                            /* 4945 21f7 */
 206   u32 n_code_pages;                     /* number of pointers following */
 207   u32 zero1[2];
 208   struct {
 209     u16 ix;                             /* index */
 210     u16 code_page_number;               /* code page number */
 211     u32 bounds;                         /* matches corresponding word
 212                                            in data block */
 213     secno code_page_data;               /* sector number of a code_page_data
 214                                            containing c.p. array */
 215     u16 index;                          /* index in c.p. array in that sector*/
 216     u16 unknown;                        /* some unknown value; usually 0;
 217                                            2 in Japanese version */
 218   } array[31];                          /* unknown length */
 219 };
 220
 221 /* blocks pointed to by code_page_directory */
 222
 223 #define CP_DATA_MAGIC 0x894521f7
 224
 225 struct code_page_data
 226 {
 227   u32 magic;                            /* 8945 21f7 */
 228   u32 n_used;                           /* # elements used in c_p_data[] */
 229   u32 bounds[3];                        /* looks a bit like
 230                                              (beg1,end1), (beg2,end2)
 231                                            one byte each */
 232   u16 offs[3];                          /* offsets from start of sector
 233                                            to start of c_p_data[ix] */
 234   struct {
 235     u16 ix;                             /* index */
 236     u16 code_page_number;               /* code page number */
 237     u16 unknown;                        /* the same as in cp directory */
 238     u8 map[128];                        /* upcase table for chars 80..ff */
 239     u16 zero2;
 240   } code_page[3];
 241   u8 incognita[78];
 242 };
 243
 244
 245 /* Free space bitmaps are 4 sectors long, which is 16384 bits.
 246    16384 sectors is 8 meg, and each 8 meg band has a 4-sector bitmap.
 247    Bit order in the maps is little-endian.  0 means taken, 1 means free.
 248
 249    Bit map sectors are marked allocated in the bit maps, and so are sectors
 250    off the end of the partition.
 251
 252    Band 0 is sectors 0-3fff, its map is in sectors 18-1b.
 253    Band 1 is 4000-7fff, its map is in 7ffc-7fff.
 254    Band 2 is 8000-ffff, its map is in 8000-8003.
 255    The remaining bands have maps in their first (even) or last (odd) 4 sectors
 256      -- if the last, partial, band is odd its map is in its last 4 sectors.
 257
 258    The bitmap locations are given in a table pointed to by the super block.
 259    No doubt they aren't constrained to be at 18, 7ffc, 8000, ...; that is
 260    just where they usually are.
 261
 262    The "directory band" is a bunch of sectors preallocated for dnodes.
 263    It has a 4-sector free space bitmap of its own.  Each bit in the map
 264    corresponds to one 4-sector dnode, bit 0 of the map corresponding to
 265    the first 4 sectors of the directory band.  The entire band is marked
 266    allocated in the main bitmap.   The super block gives the locations
 267    of the directory band and its bitmap.  ("band" doesn't mean it is
 268    8 meg long; it isn't.)  */
 269
 270
 271 /* dnode: directory.  4 sectors long */
 272
 273 /* A directory is a tree of dnodes.  The fnode for a directory
 274    contains one pointer, to the root dnode of the tree.  The fnode
 275    never moves, the dnodes do the B-tree thing, splitting and merging
 276    as files are added and removed.  */
 277
 278 #define DNODE_MAGIC   0x77e40aae
 279
 280 struct dnode {
 281   u32 magic;                            /* 77e4 0aae */
 282   u32 first_free;                       /* offset from start of dnode to
 283                                            first free dir entry */
 284 #ifdef __LITTLE_ENDIAN
 285   u8 root_dnode: 1;                     /* Is it root dnode? */
 286   u8 increment_me: 7;                   /* some kind of activity counter? */
 287                                         /* Neither HPFS.IFS nor CHKDSK cares
 288                                            if you change this word */
 289 #else
 290   u8 increment_me: 7;                   /* some kind of activity counter? */
 291                                         /* Neither HPFS.IFS nor CHKDSK cares
 292                                            if you change this word */
 293   u8 root_dnode: 1;                     /* Is it root dnode? */
 294 #endif
 295   u8 increment_me2[3];
 296   secno up;                             /* (root dnode) directory's fnode
 297                                            (nonroot) parent dnode */
 298   dnode_secno self;                     /* pointer to this dnode */
 299   u8 dirent[2028];                      /* one or more dirents */
 300 };
 301
 302 struct hpfs_dirent {
 303   u16 length;                           /* offset to next dirent */
 304
 305 #ifdef __LITTLE_ENDIAN
 306   u8 first: 1;                          /* set on phony ^A^A (".") entry */
 307   u8 has_acl: 1;
 308   u8 down: 1;                           /* down pointer present (after name) */
 309   u8 last: 1;                           /* set on phony \377 entry */
 310   u8 has_ea: 1;                         /* entry has EA */
 311   u8 has_xtd_perm: 1;                   /* has extended perm list (???) */
 312   u8 has_explicit_acl: 1;
 313   u8 has_needea: 1;                     /* ?? some EA has NEEDEA set
 314                                            I have no idea why this is
 315                                            interesting in a dir entry */
 316 #else
 317   u8 has_needea: 1;                     /* ?? some EA has NEEDEA set
 318                                            I have no idea why this is
 319                                            interesting in a dir entry */
 320   u8 has_explicit_acl: 1;
 321   u8 has_xtd_perm: 1;                   /* has extended perm list (???) */
 322   u8 has_ea: 1;                         /* entry has EA */
 323   u8 last: 1;                           /* set on phony \377 entry */
 324   u8 down: 1;                           /* down pointer present (after name) */
 325   u8 has_acl: 1;
 326   u8 first: 1;                          /* set on phony ^A^A (".") entry */
 327 #endif
 328
 329 #ifdef __LITTLE_ENDIAN
 330   u8 read_only: 1;                      /* dos attrib */
 331   u8 hidden: 1;                         /* dos attrib */
 332   u8 system: 1;                         /* dos attrib */
 333   u8 flag11: 1;                         /* would be volume label dos attrib */
 334   u8 directory: 1;                      /* dos attrib */
 335   u8 archive: 1;                        /* dos attrib */
 336   u8 not_8x3: 1;                        /* name is not 8.3 */
 337   u8 flag15: 1;
 338 #else
 339   u8 flag15: 1;
 340   u8 not_8x3: 1;                        /* name is not 8.3 */
 341   u8 archive: 1;                        /* dos attrib */
 342   u8 directory: 1;                      /* dos attrib */
 343   u8 flag11: 1;                         /* would be volume label dos attrib */
 344   u8 system: 1;                         /* dos attrib */
 345   u8 hidden: 1;                         /* dos attrib */
 346   u8 read_only: 1;                      /* dos attrib */
 347 #endif
 348
 349   fnode_secno fnode;                    /* fnode giving allocation info */
 350   time32_t write_date;                  /* mtime */
 351   u32 file_size;                        /* file length, bytes */
 352   time32_t read_date;                   /* atime */
 353   time32_t creation_date;                       /* ctime */
 354   u32 ea_size;                          /* total EA length, bytes */
 355   u8 no_of_acls;                        /* number of ACL's (low 3 bits) */
 356   u8 ix;                                /* code page index (of filename), see
 357                                            struct code_page_data */
 358   u8 namelen, name[1];                  /* file name */
 359   /* dnode_secno down;    btree down pointer, if present,
 360                           follows name on next word boundary, or maybe it
 361                           precedes next dirent, which is on a word boundary. */
 362 };
 363
 364
 365 /* B+ tree: allocation info in fnodes and anodes */
 366
 367 /* dnodes point to fnodes which are responsible for listing the sectors
 368    assigned to the file.  This is done with trees of (length,address)
 369    pairs.  (Actually triples, of (length, file-address, disk-address)
 370    which can represent holes.  Find out if HPFS does that.)
 371    At any rate, fnodes contain a small tree; if subtrees are needed
 372    they occupy essentially a full block in anodes.  A leaf-level tree node
 373    has 3-word entries giving sector runs, a non-leaf node has 2-word
 374    entries giving subtree pointers.  A flag in the header says which. */
 375
 376 struct bplus_leaf_node
 377 {
 378   u32 file_secno;                       /* first file sector in extent */
 379   u32 length;                           /* length, sectors */
 380   secno disk_secno;                     /* first corresponding disk sector */
 381 };
 382
 383 struct bplus_internal_node
 384 {
 385   u32 file_secno;                       /* subtree maps sectors < this  */
 386   anode_secno down;                     /* pointer to subtree */
 387 };
 388
 389 struct bplus_header
 390 {
 391 #ifdef __LITTLE_ENDIAN
 392   u8 hbff: 1;                   /* high bit of first free entry offset */
 393   u8 flag1234: 4;
 394   u8 fnode_parent: 1;                   /* ? we're pointed to by an fnode,
 395                                            the data btree or some ea or the
 396                                            main ea bootage pointer ea_secno */
 397                                         /* also can get set in fnodes, which
 398                                            may be a chkdsk glitch or may mean
 399                                            this bit is irrelevant in fnodes,
 400                                            or this interpretation is all wet */
 401   u8 binary_search: 1;                  /* suggest binary search (unused) */
 402   u8 internal: 1;                       /* 1 -> (internal) tree of anodes
 403                                            0 -> (leaf) list of extents */
 404 #else
 405   u8 internal: 1;                       /* 1 -> (internal) tree of anodes
 406                                            0 -> (leaf) list of extents */
 407   u8 binary_search: 1;                  /* suggest binary search (unused) */
 408   u8 fnode_parent: 1;                   /* ? we're pointed to by an fnode,
 409                                            the data btree or some ea or the
 410                                            main ea bootage pointer ea_secno */
 411                                         /* also can get set in fnodes, which
 412                                            may be a chkdsk glitch or may mean
 413                                            this bit is irrelevant in fnodes,
 414                                            or this interpretation is all wet */
 415   u8 flag1234: 4;
 416   u8 hbff: 1;                   /* high bit of first free entry offset */
 417 #endif
 418   u8 fill[3];
 419   u8 n_free_nodes;                      /* free nodes in following array */
 420   u8 n_used_nodes;                      /* used nodes in following array */
 421   u16 first_free;                       /* offset from start of header to
 422                                            first free node in array */
 423   union {
 424     struct bplus_internal_node internal[0]; /* (internal) 2-word entries giving
 425                                                subtree pointers */
 426     struct bplus_leaf_node external[0];     /* (external) 3-word entries giving
 427                                                sector runs */
 428   } u;
 429 };
 430
 431 /* fnode: root of allocation b+ tree, and EA's */
 432
 433 /* Every file and every directory has one fnode, pointed to by the directory
 434    entry and pointing to the file's sectors or directory's root dnode.  EA's
 435    are also stored here, and there are said to be ACL's somewhere here too. */
 436
 437 #define FNODE_MAGIC 0xf7e40aae
 438
 439 struct fnode
 440 {
 441   u32 magic;                            /* f7e4 0aae */
 442   u32 zero1[2];                         /* read history */
 443   u8 len, name[15];                     /* true length, truncated name */
 444   fnode_secno up;                       /* pointer to file's directory fnode */
 445   secno acl_size_l;
 446   secno acl_secno;
 447   u16 acl_size_s;
 448   u8 acl_anode;
 449   u8 zero2;                             /* history bit count */
 450   u32 ea_size_l;                        /* length of disk-resident ea's */
 451   secno ea_secno;                       /* first sector of disk-resident ea's*/
 452   u16 ea_size_s;                        /* length of fnode-resident ea's */
 453
 454 #ifdef __LITTLE_ENDIAN
 455   u8 flag0: 1;
 456   u8 ea_anode: 1;                       /* 1 -> ea_secno is an anode */
 457   u8 flag234567: 6;
 458 #else
 459   u8 flag234567: 6;
 460   u8 ea_anode: 1;                       /* 1 -> ea_secno is an anode */
 461   u8 flag0: 1;
 462 #endif
 463
 464 #ifdef __LITTLE_ENDIAN
 465   u8 dirflag: 1;                        /* 1 -> directory.  first & only extent
 466                                            points to dnode. */
 467   u8 flag9012345: 7;
 468 #else
 469   u8 flag9012345: 7;
 470   u8 dirflag: 1;                        /* 1 -> directory.  first & only extent
 471                                            points to dnode. */
 472 #endif
 473
 474   struct bplus_header btree;            /* b+ tree, 8 extents or 12 subtrees */
 475   union {
 476     struct bplus_leaf_node external[8];
 477     struct bplus_internal_node internal[12];
 478   } u;
 479
 480   u32 file_size;                        /* file length, bytes */
 481   u32 n_needea;                         /* number of EA's with NEEDEA set */
 482   u8 user_id[16];                       /* unused */
 483   u16 ea_offs;                          /* offset from start of fnode
 484                                            to first fnode-resident ea */
 485   u8 dasd_limit_treshhold;
 486   u8 dasd_limit_delta;
 487   u32 dasd_limit;
 488   u32 dasd_usage;
 489   u8 ea[316];                           /* zero or more EA's, packed together
 490                                            with no alignment padding.
 491                                            (Do not use this name, get here
 492                                            via fnode + ea_offs. I think.) */
 493 };
 494
 495
 496 /* anode: 99.44% pure allocation tree */
 497
 498 #define ANODE_MAGIC 0x37e40aae
 499
 500 struct anode
 501 {
 502   u32 magic;                            /* 37e4 0aae */
 503   anode_secno self;                     /* pointer to this anode */
 504   secno up;                             /* parent anode or fnode */
 505
 506   struct bplus_header btree;            /* b+tree, 40 extents or 60 subtrees */
 507   union {
 508     struct bplus_leaf_node external[40];
 509     struct bplus_internal_node internal[60];
 510   } u;
 511
 512   u32 fill[3];                          /* unused */
 513 };
 514
 515
 516 /* extended attributes.
 517
 518    A file's EA info is stored as a list of (name,value) pairs.  It is
 519    usually in the fnode, but (if it's large) it is moved to a single
 520    sector run outside the fnode, or to multiple runs with an anode tree
 521    that points to them.
 522
 523    The value of a single EA is stored along with the name, or (if large)
 524    it is moved to a single sector run, or multiple runs pointed to by an
 525    anode tree, pointed to by the value field of the (name,value) pair.
 526
 527    Flags in the EA tell whether the value is immediate, in a single sector
 528    run, or in multiple runs.  Flags in the fnode tell whether the EA list
 529    is immediate, in a single run, or in multiple runs. */
 530
 531 struct extended_attribute
 532 {
 533 #ifdef __LITTLE_ENDIAN
 534   u8 indirect: 1;                       /* 1 -> value gives sector number
 535                                            where real value starts */
 536   u8 anode: 1;                          /* 1 -> sector is an anode
 537                                            that points to fragmented value */
 538   u8 flag23456: 5;
 539   u8 needea: 1;                         /* required ea */
 540 #else
 541   u8 needea: 1;                         /* required ea */
 542   u8 flag23456: 5;
 543   u8 anode: 1;                          /* 1 -> sector is an anode
 544                                            that points to fragmented value */
 545   u8 indirect: 1;                       /* 1 -> value gives sector number
 546                                            where real value starts */
 547 #endif
 548   u8 namelen;                           /* length of name, bytes */
 549   u8 valuelen_lo;                       /* length of value, bytes */
 550   u8 valuelen_hi;                       /* length of value, bytes */
 551   u8 name[0];
 552   /*
 553     u8 name[namelen];                   ascii attrib name
 554     u8 nul;                             terminating '\0', not counted
 555     u8 value[valuelen];                 value, arbitrary
 556       if this.indirect, valuelen is 8 and the value is
 557         u32 length;                     real length of value, bytes
 558         secno secno;                    sector address where it starts
 559       if this.anode, the above sector number is the root of an anode tree
 560         which points to the value.
 561   */
 562 };
 563
 564 /*
 565    Local Variables:
 566    comment-column: 40
 567    End:
 568 */