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   __le16 sectors_per_fat;
  55   __le16 sectors_per_track;
  56   __le16 heads_per_cyl;
  57   __le32 n_hidden_sectors;
  58   __le32 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   __le16 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   __le32 magic;                         /* f995 e849 */
  79   __le32 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   __le16 zero;                          /* 0 */
  85   __le32 root;                          /* fnode of root directory */
  86   __le32 n_sectors;                     /* size of filesystem */
  87   __le32 n_badblocks;                   /* number of bad blocks */
  88   __le32 bitmaps;                       /* pointers to free space bit maps */
  89   __le32 zero1;                         /* 0 */
  90   __le32 badblocks;                     /* bad block list */
  91   __le32 zero3;                         /* 0 */
  92   __le32 last_chkdsk;                   /* date last checked, 0 if never */
  93   __le32 last_optimize;                 /* date last optimized, 0 if never */
  94   __le32 n_dir_band;                    /* number of sectors in dir band */
  95   __le32 dir_band_start;                        /* first sector in dir band */
  96   __le32 dir_band_end;                  /* last sector in dir band */
  97   __le32 dir_band_bitmap;               /* free space map, 1 dnode per bit */
  98   u8 volume_name[32];                   /* not used */
  99   __le32 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   __le32 magic;                         /* f991 1849 */
 113   __le32 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   __le32 hotfix_map;                    /* info about remapped bad sectors */
 157   __le32 n_spares_used;                 /* number of hotfixes */
 158   __le32 n_spares;                      /* number of spares in hotfix map */
 159   __le32 n_dnode_spares_free;           /* spare dnodes unused */
 160   __le32 n_dnode_spares;                /* length of spare_dnodes[] list,
 161                                            follows in this block*/
 162   __le32 code_page_dir;                 /* code page directory block */
 163   __le32 n_code_pages;                  /* number of code pages */
 164   __le32 super_crc;                     /* on HPFS386 and LAN Server this is
 165                                            checksum of superblock, on normal
 166                                            OS/2 unused */
 167   __le32 spare_crc;                     /* on HPFS386 checksum of spareblock */
 168   __le32 zero1[15];                     /* unused */
 169   __le32 spare_dnodes[100];             /* emergency free dnode list */
 170   __le32 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   __le32 magic;                         /* 4945 21f7 */
 206   __le32 n_code_pages;                  /* number of pointers following */
 207   __le32 zero1[2];
 208   struct {
 209     __le16 ix;                          /* index */
 210     __le16 code_page_number;            /* code page number */
 211     __le32 bounds;                      /* matches corresponding word
 212                                            in data block */
 213     __le32 code_page_data;              /* sector number of a code_page_data
 214                                            containing c.p. array */
 215     __le16 index;                       /* index in c.p. array in that sector*/
 216     __le16 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   __le32 magic;                         /* 8945 21f7 */
 228   __le32 n_used;                        /* # elements used in c_p_data[] */
 229   __le32 bounds[3];                     /* looks a bit like
 230                                              (beg1,end1), (beg2,end2)
 231                                            one byte each */
 232   __le16 offs[3];                       /* offsets from start of sector
 233                                            to start of c_p_data[ix] */
 234   struct {
 235     __le16 ix;                          /* index */
 236     __le16 code_page_number;            /* code page number */
 237     __le16 unknown;                     /* the same as in cp directory */
 238     u8 map[128];                        /* upcase table for chars 80..ff */
 239     __le16 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   __le32 magic;                         /* 77e4 0aae */
 282   __le32 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   __le32 up;                            /* (root dnode) directory's fnode
 297                                            (nonroot) parent dnode */
 298   __le32 self;                  /* pointer to this dnode */
 299   u8 dirent[2028];                      /* one or more dirents */
 300 };
 301
 302 struct hpfs_dirent {
 303   __le16 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   __le32 fnode;                         /* fnode giving allocation info */
 350   __le32 write_date;                    /* mtime */
 351   __le32 file_size;                     /* file length, bytes */
 352   __le32 read_date;                     /* atime */
 353   __le32 creation_date;                 /* ctime */
 354   __le32 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   __le32 file_secno;                    /* first file sector in extent */
 379   __le32 length;                        /* length, sectors */
 380   __le32 disk_secno;                    /* first corresponding disk sector */
 381 };
 382
 383 struct bplus_internal_node
 384 {
 385   __le32 file_secno;                    /* subtree maps sectors < this  */
 386   __le32 down;                          /* pointer to subtree */
 387 };
 388
 389 enum {
 390         BP_hbff = 1,
 391         BP_fnode_parent = 0x20,
 392         BP_binary_search = 0x40,
 393         BP_internal = 0x80
 394 };
 395 struct bplus_header
 396 {
 397   u8 flags;                             /* bit 0 - high bit of first free entry offset
 398                                            bit 5 - we're pointed to by an fnode,
 399                                            the data btree or some ea or the
 400                                            main ea bootage pointer ea_secno
 401                                            bit 6 - suggest binary search (unused)
 402                                            bit 7 - 1 -> (internal) tree of anodes
 403                                                    0 -> (leaf) list of extents */
 404   u8 fill[3];
 405   u8 n_free_nodes;                      /* free nodes in following array */
 406   u8 n_used_nodes;                      /* used nodes in following array */
 407   __le16 first_free;                    /* offset from start of header to
 408                                            first free node in array */
 409   union {
 410     struct bplus_internal_node internal[0]; /* (internal) 2-word entries giving
 411                                                subtree pointers */
 412     struct bplus_leaf_node external[0];     /* (external) 3-word entries giving
 413                                                sector runs */
 414   } u;
 415 };
 416
 417 static inline bool bp_internal(struct bplus_header *bp)
 418 {
 419         return bp->flags & BP_internal;
 420 }
 421
 422 static inline bool bp_fnode_parent(struct bplus_header *bp)
 423 {
 424         return bp->flags & BP_fnode_parent;
 425 }
 426
 427 /* fnode: root of allocation b+ tree, and EA's */
 428
 429 /* Every file and every directory has one fnode, pointed to by the directory
 430    entry and pointing to the file's sectors or directory's root dnode.  EA's
 431    are also stored here, and there are said to be ACL's somewhere here too. */
 432
 433 #define FNODE_MAGIC 0xf7e40aae
 434
 435 enum {FNODE_anode = cpu_to_le16(2), FNODE_dir = cpu_to_le16(256)};
 436 struct fnode
 437 {
 438   __le32 magic;                         /* f7e4 0aae */
 439   __le32 zero1[2];                      /* read history */
 440   u8 len, name[15];                     /* true length, truncated name */
 441   __le32 up;                            /* pointer to file's directory fnode */
 442   __le32 acl_size_l;
 443   __le32 acl_secno;
 444   __le16 acl_size_s;
 445   u8 acl_anode;
 446   u8 zero2;                             /* history bit count */
 447   __le32 ea_size_l;                     /* length of disk-resident ea's */
 448   __le32 ea_secno;                      /* first sector of disk-resident ea's*/
 449   __le16 ea_size_s;                     /* length of fnode-resident ea's */
 450
 451   __le16 flags;                         /* bit 1 set -> ea_secno is an anode */
 452                                         /* bit 8 set -> directory.  first & only extent
 453                                            points to dnode. */
 454   struct bplus_header btree;            /* b+ tree, 8 extents or 12 subtrees */
 455   union {
 456     struct bplus_leaf_node external[8];
 457     struct bplus_internal_node internal[12];
 458   } u;
 459
 460   __le32 file_size;                     /* file length, bytes */
 461   __le32 n_needea;                      /* number of EA's with NEEDEA set */
 462   u8 user_id[16];                       /* unused */
 463   __le16 ea_offs;                       /* offset from start of fnode
 464                                            to first fnode-resident ea */
 465   u8 dasd_limit_treshhold;
 466   u8 dasd_limit_delta;
 467   __le32 dasd_limit;
 468   __le32 dasd_usage;
 469   u8 ea[316];                           /* zero or more EA's, packed together
 470                                            with no alignment padding.
 471                                            (Do not use this name, get here
 472                                            via fnode + ea_offs. I think.) */
 473 };
 474
 475 static inline bool fnode_in_anode(struct fnode *p)
 476 {
 477         return (p->flags & FNODE_anode) != 0;
 478 }
 479
 480 static inline bool fnode_is_dir(struct fnode *p)
 481 {
 482         return (p->flags & FNODE_dir) != 0;
 483 }
 484
 485
 486 /* anode: 99.44% pure allocation tree */
 487
 488 #define ANODE_MAGIC 0x37e40aae
 489
 490 struct anode
 491 {
 492   __le32 magic;                         /* 37e4 0aae */
 493   __le32 self;                          /* pointer to this anode */
 494   __le32 up;                            /* parent anode or fnode */
 495
 496   struct bplus_header btree;            /* b+tree, 40 extents or 60 subtrees */
 497   union {
 498     struct bplus_leaf_node external[40];
 499     struct bplus_internal_node internal[60];
 500   } u;
 501
 502   __le32 fill[3];                       /* unused */
 503 };
 504
 505
 506 /* extended attributes.
 507
 508    A file's EA info is stored as a list of (name,value) pairs.  It is
 509    usually in the fnode, but (if it's large) it is moved to a single
 510    sector run outside the fnode, or to multiple runs with an anode tree
 511    that points to them.
 512
 513    The value of a single EA is stored along with the name, or (if large)
 514    it is moved to a single sector run, or multiple runs pointed to by an
 515    anode tree, pointed to by the value field of the (name,value) pair.
 516
 517    Flags in the EA tell whether the value is immediate, in a single sector
 518    run, or in multiple runs.  Flags in the fnode tell whether the EA list
 519    is immediate, in a single run, or in multiple runs. */
 520
 521 enum {EA_indirect = 1, EA_anode = 2, EA_needea = 128 };
 522 struct extended_attribute
 523 {
 524   u8 flags;                             /* bit 0 set -> value gives sector number
 525                                            where real value starts */
 526                                         /* bit 1 set -> sector is an anode
 527                                            that points to fragmented value */
 528                                         /* bit 7 set -> required ea */
 529   u8 namelen;                           /* length of name, bytes */
 530   u8 valuelen_lo;                       /* length of value, bytes */
 531   u8 valuelen_hi;                       /* length of value, bytes */
 532   u8 name[];
 533   /*
 534     u8 name[namelen];                   ascii attrib name
 535     u8 nul;                             terminating '\0', not counted
 536     u8 value[valuelen];                 value, arbitrary
 537       if this.flags & 1, valuelen is 8 and the value is
 538         u32 length;                     real length of value, bytes
 539         secno secno;                    sector address where it starts
 540       if this.anode, the above sector number is the root of an anode tree
 541         which points to the value.
 542   */
 543 };
 544
 545 static inline bool ea_indirect(struct extended_attribute *ea)
 546 {
 547         return ea->flags & EA_indirect;
 548 }
 549
 550 static inline bool ea_in_anode(struct extended_attribute *ea)
 551 {
 552         return ea->flags & EA_anode;
 553 }
 554
 555 /*
 556    Local Variables:
 557    comment-column: 40
 558    End:
 559 */