fs/hpfs/hpfs.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  *  linux/fs/hpfs/hpfs.h
   4  *
   5  *  HPFS structures by Chris Smith, 1993
   6  *
   7  *  a little bit modified by Mikulas Patocka, 1998-1999
   8  */
   9
  10 /* The paper
  11
  12      Duncan, Roy
  13      Design goals and implementation of the new High Performance File System
  14      Microsoft Systems Journal  Sept 1989  v4 n5 p1(13)
  15
  16    describes what HPFS looked like when it was new, and it is the source
  17    of most of the information given here.  The rest is conjecture.
  18
  19    For definitive information on the Duncan paper, see it, not this file.
  20    For definitive information on HPFS, ask somebody else -- this is guesswork.
  21    There are certain to be many mistakes. */
  22
  23 #if !defined(__LITTLE_ENDIAN) && !defined(__BIG_ENDIAN)
  24 #error unknown endian
  25 #endif
  26
  27 /* Notation */
  28
  29 typedef u32 secno;                      /* sector number, partition relative */
  30
  31 typedef secno dnode_secno;              /* sector number of a dnode */
  32 typedef secno fnode_secno;              /* sector number of an fnode */
  33 typedef secno anode_secno;              /* sector number of an anode */
  34
  35 typedef u32 time32_t;           /* 32-bit time_t type */
  36
  37 /* sector 0 */
  38
  39 /* The boot block is very like a FAT boot block, except that the
  40    29h signature byte is 28h instead, and the ID string is "HPFS". */
  41
  42 #define BB_MAGIC 0xaa55
  43
  44 struct hpfs_boot_block
  45 {
  46   u8 jmp[3];
  47   u8 oem_id[8];
  48   u8 bytes_per_sector[2];       /* 512 */
  49   u8 sectors_per_cluster;
  50   u8 n_reserved_sectors[2];
  51   u8 n_fats;
  52   u8 n_rootdir_entries[2];
  53   u8 n_sectors_s[2];
  54   u8 media_byte;
  55   __le16 sectors_per_fat;
  56   __le16 sectors_per_track;
  57   __le16 heads_per_cyl;
  58   __le32 n_hidden_sectors;
  59   __le32 n_sectors_l;           /* size of partition */
  60   u8 drive_number;
  61   u8 mbz;
  62   u8 sig_28h;                   /* 28h */
  63   u8 vol_serno[4];
  64   u8 vol_label[11];
  65   u8 sig_hpfs[8];               /* "HPFS    " */
  66   u8 pad[448];
  67   __le16 magic;                 /* aa55 */
  68 };
  69
  70
  71 /* sector 16 */
  72
  73 /* The super block has the pointer to the root directory. */
  74
  75 #define SB_MAGIC 0xf995e849
  76
  77 struct hpfs_super_block
  78 {
  79   __le32 magic;                         /* f995 e849 */
  80   __le32 magic1;                        /* fa53 e9c5, more magic? */
  81   u8 version;                           /* version of a filesystem  usually 2 */
  82   u8 funcversion;                       /* functional version - oldest version
  83                                            of filesystem that can understand
  84                                            this disk */
  85   __le16 zero;                          /* 0 */
  86   __le32 root;                          /* fnode of root directory */
  87   __le32 n_sectors;                     /* size of filesystem */
  88   __le32 n_badblocks;                   /* number of bad blocks */
  89   __le32 bitmaps;                       /* pointers to free space bit maps */
  90   __le32 zero1;                         /* 0 */
  91   __le32 badblocks;                     /* bad block list */
  92   __le32 zero3;                         /* 0 */
  93   __le32 last_chkdsk;                   /* date last checked, 0 if never */
  94   __le32 last_optimize;                 /* date last optimized, 0 if never */
  95   __le32 n_dir_band;                    /* number of sectors in dir band */
  96   __le32 dir_band_start;                        /* first sector in dir band */
  97   __le32 dir_band_end;                  /* last sector in dir band */
  98   __le32 dir_band_bitmap;               /* free space map, 1 dnode per bit */
  99   u8 volume_name[32];                   /* not used */
 100   __le32 user_id_table;                 /* 8 preallocated sectors - user id */
 101   u32 zero6[103];                       /* 0 */
 102 };
 103
 104
 105 /* sector 17 */
 106
 107 /* The spare block has pointers to spare sectors.  */
 108
 109 #define SP_MAGIC 0xf9911849
 110
 111 struct hpfs_spare_block
 112 {
 113   __le32 magic;                         /* f991 1849 */
 114   __le32 magic1;                                /* fa52 29c5, more magic? */
 115
 116 #ifdef __LITTLE_ENDIAN
 117   u8 dirty: 1;                          /* 0 clean, 1 "improperly stopped" */
 118   u8 sparedir_used: 1;                  /* spare dirblks used */
 119   u8 hotfixes_used: 1;                  /* hotfixes used */
 120   u8 bad_sector: 1;                     /* bad sector, corrupted disk (???) */
 121   u8 bad_bitmap: 1;                     /* bad bitmap */
 122   u8 fast: 1;                           /* partition was fast formatted */
 123   u8 old_wrote: 1;                      /* old version wrote to partition */
 124   u8 old_wrote_1: 1;                    /* old version wrote to partition (?) */
 125 #else
 126   u8 old_wrote_1: 1;                    /* old version wrote to partition (?) */
 127   u8 old_wrote: 1;                      /* old version wrote to partition */
 128   u8 fast: 1;                           /* partition was fast formatted */
 129   u8 bad_bitmap: 1;                     /* bad bitmap */
 130   u8 bad_sector: 1;                     /* bad sector, corrupted disk (???) */
 131   u8 hotfixes_used: 1;                  /* hotfixes used */
 132   u8 sparedir_used: 1;                  /* spare dirblks used */
 133   u8 dirty: 1;                          /* 0 clean, 1 "improperly stopped" */
 134 #endif
 135
 136 #ifdef __LITTLE_ENDIAN
 137   u8 install_dasd_limits: 1;            /* HPFS386 flags */
 138   u8 resynch_dasd_limits: 1;
 139   u8 dasd_limits_operational: 1;
 140   u8 multimedia_active: 1;
 141   u8 dce_acls_active: 1;
 142   u8 dasd_limits_dirty: 1;
 143   u8 flag67: 2;
 144 #else
 145   u8 flag67: 2;
 146   u8 dasd_limits_dirty: 1;
 147   u8 dce_acls_active: 1;
 148   u8 multimedia_active: 1;
 149   u8 dasd_limits_operational: 1;
 150   u8 resynch_dasd_limits: 1;
 151   u8 install_dasd_limits: 1;            /* HPFS386 flags */
 152 #endif
 153
 154   u8 mm_contlgulty;
 155   u8 unused;
 156
 157   __le32 hotfix_map;                    /* info about remapped bad sectors */
 158   __le32 n_spares_used;                 /* number of hotfixes */
 159   __le32 n_spares;                      /* number of spares in hotfix map */
 160   __le32 n_dnode_spares_free;           /* spare dnodes unused */
 161   __le32 n_dnode_spares;                /* length of spare_dnodes[] list,
 162                                            follows in this block*/
 163   __le32 code_page_dir;                 /* code page directory block */
 164   __le32 n_code_pages;                  /* number of code pages */
 165   __le32 super_crc;                     /* on HPFS386 and LAN Server this is
 166                                            checksum of superblock, on normal
 167                                            OS/2 unused */
 168   __le32 spare_crc;                     /* on HPFS386 checksum of spareblock */
 169   __le32 zero1[15];                     /* unused */
 170   __le32 spare_dnodes[100];             /* emergency free dnode list */
 171   __le32 zero2[1];                      /* room for more? */
 172 };
 173
 174 /* The bad block list is 4 sectors long.  The first word must be zero,
 175    the remaining words give n_badblocks bad block numbers.
 176    I bet you can see it coming... */
 177
 178 #define BAD_MAGIC 0
 179
 180 /* The hotfix map is 4 sectors long.  It looks like
 181
 182        secno from[n_spares];
 183        secno to[n_spares];
 184
 185    The to[] list is initialized to point to n_spares preallocated empty
 186    sectors.  The from[] list contains the sector numbers of bad blocks
 187    which have been remapped to corresponding sectors in the to[] list.
 188    n_spares_used gives the length of the from[] list. */
 189
 190
 191 /* Sectors 18 and 19 are preallocated and unused.
 192    Maybe they're spares for 16 and 17, but simple substitution fails. */
 193
 194
 195 /* The code page info pointed to by the spare block consists of an index
 196    block and blocks containing uppercasing tables.  I don't know what
 197    these are for (CHKDSK, maybe?) -- OS/2 does not seem to use them
 198    itself.  Linux doesn't use them either. */
 199
 200 /* block pointed to by spareblock->code_page_dir */
 201
 202 #define CP_DIR_MAGIC 0x494521f7
 203
 204 struct code_page_directory
 205 {
 206   __le32 magic;                         /* 4945 21f7 */
 207   __le32 n_code_pages;                  /* number of pointers following */
 208   __le32 zero1[2];
 209   struct {
 210     __le16 ix;                          /* index */
 211     __le16 code_page_number;            /* code page number */
 212     __le32 bounds;                      /* matches corresponding word
 213                                            in data block */
 214     __le32 code_page_data;              /* sector number of a code_page_data
 215                                            containing c.p. array */
 216     __le16 index;                       /* index in c.p. array in that sector*/
 217     __le16 unknown;                     /* some unknown value; usually 0;
 218                                            2 in Japanese version */
 219   } array[31];                          /* unknown length */
 220 };
 221
 222 /* blocks pointed to by code_page_directory */
 223
 224 #define CP_DATA_MAGIC 0x894521f7
 225
 226 struct code_page_data
 227 {
 228   __le32 magic;                         /* 8945 21f7 */
 229   __le32 n_used;                        /* # elements used in c_p_data[] */
 230   __le32 bounds[3];                     /* looks a bit like
 231                                              (beg1,end1), (beg2,end2)
 232                                            one byte each */
 233   __le16 offs[3];                       /* offsets from start of sector
 234                                            to start of c_p_data[ix] */
 235   struct {
 236     __le16 ix;                          /* index */
 237     __le16 code_page_number;            /* code page number */
 238     __le16 unknown;                     /* the same as in cp directory */
 239     u8 map[128];                        /* upcase table for chars 80..ff */
 240     __le16 zero2;
 241   } code_page[3];
 242   u8 incognita[78];
 243 };
 244
 245
 246 /* Free space bitmaps are 4 sectors long, which is 16384 bits.
 247    16384 sectors is 8 meg, and each 8 meg band has a 4-sector bitmap.
 248    Bit order in the maps is little-endian.  0 means taken, 1 means free.
 249
 250    Bit map sectors are marked allocated in the bit maps, and so are sectors
 251    off the end of the partition.
 252
 253    Band 0 is sectors 0-3fff, its map is in sectors 18-1b.
 254    Band 1 is 4000-7fff, its map is in 7ffc-7fff.
 255    Band 2 is 8000-ffff, its map is in 8000-8003.
 256    The remaining bands have maps in their first (even) or last (odd) 4 sectors
 257      -- if the last, partial, band is odd its map is in its last 4 sectors.
 258
 259    The bitmap locations are given in a table pointed to by the super block.
 260    No doubt they aren't constrained to be at 18, 7ffc, 8000, ...; that is
 261    just where they usually are.
 262
 263    The "directory band" is a bunch of sectors preallocated for dnodes.
 264    It has a 4-sector free space bitmap of its own.  Each bit in the map
 265    corresponds to one 4-sector dnode, bit 0 of the map corresponding to
 266    the first 4 sectors of the directory band.  The entire band is marked
 267    allocated in the main bitmap.   The super block gives the locations
 268    of the directory band and its bitmap.  ("band" doesn't mean it is
 269    8 meg long; it isn't.)  */
 270
 271
 272 /* dnode: directory.  4 sectors long */
 273
 274 /* A directory is a tree of dnodes.  The fnode for a directory
 275    contains one pointer, to the root dnode of the tree.  The fnode
 276    never moves, the dnodes do the B-tree thing, splitting and merging
 277    as files are added and removed.  */
 278
 279 #define DNODE_MAGIC   0x77e40aae
 280
 281 struct dnode {
 282   __le32 magic;                         /* 77e4 0aae */
 283   __le32 first_free;                    /* offset from start of dnode to
 284                                            first free dir entry */
 285 #ifdef __LITTLE_ENDIAN
 286   u8 root_dnode: 1;                     /* Is it root dnode? */
 287   u8 increment_me: 7;                   /* some kind of activity counter? */
 288                                         /* Neither HPFS.IFS nor CHKDSK cares
 289                                            if you change this word */
 290 #else
 291   u8 increment_me: 7;                   /* some kind of activity counter? */
 292                                         /* Neither HPFS.IFS nor CHKDSK cares
 293                                            if you change this word */
 294   u8 root_dnode: 1;                     /* Is it root dnode? */
 295 #endif
 296   u8 increment_me2[3];
 297   __le32 up;                            /* (root dnode) directory's fnode
 298                                            (nonroot) parent dnode */
 299   __le32 self;                  /* pointer to this dnode */
 300   u8 dirent[2028];                      /* one or more dirents */
 301 };
 302
 303 struct hpfs_dirent {
 304   __le16 length;                        /* offset to next dirent */
 305
 306 #ifdef __LITTLE_ENDIAN
 307   u8 first: 1;                          /* set on phony ^A^A (".") entry */
 308   u8 has_acl: 1;
 309   u8 down: 1;                           /* down pointer present (after name) */
 310   u8 last: 1;                           /* set on phony \377 entry */
 311   u8 has_ea: 1;                         /* entry has EA */
 312   u8 has_xtd_perm: 1;                   /* has extended perm list (???) */
 313   u8 has_explicit_acl: 1;
 314   u8 has_needea: 1;                     /* ?? some EA has NEEDEA set
 315                                            I have no idea why this is
 316                                            interesting in a dir entry */
 317 #else
 318   u8 has_needea: 1;                     /* ?? some EA has NEEDEA set
 319                                            I have no idea why this is
 320                                            interesting in a dir entry */
 321   u8 has_explicit_acl: 1;
 322   u8 has_xtd_perm: 1;                   /* has extended perm list (???) */
 323   u8 has_ea: 1;                         /* entry has EA */
 324   u8 last: 1;                           /* set on phony \377 entry */
 325   u8 down: 1;                           /* down pointer present (after name) */
 326   u8 has_acl: 1;
 327   u8 first: 1;                          /* set on phony ^A^A (".") entry */
 328 #endif
 329
 330 #ifdef __LITTLE_ENDIAN
 331   u8 read_only: 1;                      /* dos attrib */
 332   u8 hidden: 1;                         /* dos attrib */
 333   u8 system: 1;                         /* dos attrib */
 334   u8 flag11: 1;                         /* would be volume label dos attrib */
 335   u8 directory: 1;                      /* dos attrib */
 336   u8 archive: 1;                        /* dos attrib */
 337   u8 not_8x3: 1;                        /* name is not 8.3 */
 338   u8 flag15: 1;
 339 #else
 340   u8 flag15: 1;
 341   u8 not_8x3: 1;                        /* name is not 8.3 */
 342   u8 archive: 1;                        /* dos attrib */
 343   u8 directory: 1;                      /* dos attrib */
 344   u8 flag11: 1;                         /* would be volume label dos attrib */
 345   u8 system: 1;                         /* dos attrib */
 346   u8 hidden: 1;                         /* dos attrib */
 347   u8 read_only: 1;                      /* dos attrib */
 348 #endif
 349
 350   __le32 fnode;                         /* fnode giving allocation info */
 351   __le32 write_date;                    /* mtime */
 352   __le32 file_size;                     /* file length, bytes */
 353   __le32 read_date;                     /* atime */
 354   __le32 creation_date;                 /* ctime */
 355   __le32 ea_size;                       /* total EA length, bytes */
 356   u8 no_of_acls;                        /* number of ACL's (low 3 bits) */
 357   u8 ix;                                /* code page index (of filename), see
 358                                            struct code_page_data */
 359   u8 namelen, name[1];                  /* file name */
 360   /* dnode_secno down;    btree down pointer, if present,
 361                           follows name on next word boundary, or maybe it
 362                           precedes next dirent, which is on a word boundary. */
 363 };
 364
 365
 366 /* B+ tree: allocation info in fnodes and anodes */
 367
 368 /* dnodes point to fnodes which are responsible for listing the sectors
 369    assigned to the file.  This is done with trees of (length,address)
 370    pairs.  (Actually triples, of (length, file-address, disk-address)
 371    which can represent holes.  Find out if HPFS does that.)
 372    At any rate, fnodes contain a small tree; if subtrees are needed
 373    they occupy essentially a full block in anodes.  A leaf-level tree node
 374    has 3-word entries giving sector runs, a non-leaf node has 2-word
 375    entries giving subtree pointers.  A flag in the header says which. */
 376
 377 struct bplus_leaf_node
 378 {
 379   __le32 file_secno;                    /* first file sector in extent */
 380   __le32 length;                        /* length, sectors */
 381   __le32 disk_secno;                    /* first corresponding disk sector */
 382 };
 383
 384 struct bplus_internal_node
 385 {
 386   __le32 file_secno;                    /* subtree maps sectors < this  */
 387   __le32 down;                          /* pointer to subtree */
 388 };
 389
 390 enum {
 391         BP_hbff = 1,
 392         BP_fnode_parent = 0x20,
 393         BP_binary_search = 0x40,
 394         BP_internal = 0x80
 395 };
 396 struct bplus_header
 397 {
 398   u8 flags;                             /* bit 0 - high bit of first free entry offset
 399                                            bit 5 - we're pointed to by an fnode,
 400                                            the data btree or some ea or the
 401                                            main ea bootage pointer ea_secno
 402                                            bit 6 - suggest binary search (unused)
 403                                            bit 7 - 1 -> (internal) tree of anodes
 404                                                    0 -> (leaf) list of extents */
 405   u8 fill[3];
 406   u8 n_free_nodes;                      /* free nodes in following array */
 407   u8 n_used_nodes;                      /* used nodes in following array */
 408   __le16 first_free;                    /* offset from start of header to
 409                                            first free node in array */
 410   union {
 411     struct bplus_internal_node internal[0]; /* (internal) 2-word entries giving
 412                                                subtree pointers */
 413     struct bplus_leaf_node external[0];     /* (external) 3-word entries giving
 414                                                sector runs */
 415   } u;
 416 };
 417
 418 static inline bool bp_internal(struct bplus_header *bp)
 419 {
 420         return bp->flags & BP_internal;
 421 }
 422
 423 static inline bool bp_fnode_parent(struct bplus_header *bp)
 424 {
 425         return bp->flags & BP_fnode_parent;
 426 }
 427
 428 /* fnode: root of allocation b+ tree, and EA's */
 429
 430 /* Every file and every directory has one fnode, pointed to by the directory
 431    entry and pointing to the file's sectors or directory's root dnode.  EA's
 432    are also stored here, and there are said to be ACL's somewhere here too. */
 433
 434 #define FNODE_MAGIC 0xf7e40aae
 435
 436 enum {FNODE_anode = cpu_to_le16(2), FNODE_dir = cpu_to_le16(256)};
 437 struct fnode
 438 {
 439   __le32 magic;                         /* f7e4 0aae */
 440   __le32 zero1[2];                      /* read history */
 441   u8 len, name[15];                     /* true length, truncated name */
 442   __le32 up;                            /* pointer to file's directory fnode */
 443   __le32 acl_size_l;
 444   __le32 acl_secno;
 445   __le16 acl_size_s;
 446   u8 acl_anode;
 447   u8 zero2;                             /* history bit count */
 448   __le32 ea_size_l;                     /* length of disk-resident ea's */
 449   __le32 ea_secno;                      /* first sector of disk-resident ea's*/
 450   __le16 ea_size_s;                     /* length of fnode-resident ea's */
 451
 452   __le16 flags;                         /* bit 1 set -> ea_secno is an anode */
 453                                         /* bit 8 set -> directory.  first & only extent
 454                                            points to dnode. */
 455   struct bplus_header btree;            /* b+ tree, 8 extents or 12 subtrees */
 456   union {
 457     struct bplus_leaf_node external[8];
 458     struct bplus_internal_node internal[12];
 459   } u;
 460
 461   __le32 file_size;                     /* file length, bytes */
 462   __le32 n_needea;                      /* number of EA's with NEEDEA set */
 463   u8 user_id[16];                       /* unused */
 464   __le16 ea_offs;                       /* offset from start of fnode
 465                                            to first fnode-resident ea */
 466   u8 dasd_limit_treshhold;
 467   u8 dasd_limit_delta;
 468   __le32 dasd_limit;
 469   __le32 dasd_usage;
 470   u8 ea[316];                           /* zero or more EA's, packed together
 471                                            with no alignment padding.
 472                                            (Do not use this name, get here
 473                                            via fnode + ea_offs. I think.) */
 474 };
 475
 476 static inline bool fnode_in_anode(struct fnode *p)
 477 {
 478         return (p->flags & FNODE_anode) != 0;
 479 }
 480
 481 static inline bool fnode_is_dir(struct fnode *p)
 482 {
 483         return (p->flags & FNODE_dir) != 0;
 484 }
 485
 486
 487 /* anode: 99.44% pure allocation tree */
 488
 489 #define ANODE_MAGIC 0x37e40aae
 490
 491 struct anode
 492 {
 493   __le32 magic;                         /* 37e4 0aae */
 494   __le32 self;                          /* pointer to this anode */
 495   __le32 up;                            /* parent anode or fnode */
 496
 497   struct bplus_header btree;            /* b+tree, 40 extents or 60 subtrees */
 498   union {
 499     struct bplus_leaf_node external[40];
 500     struct bplus_internal_node internal[60];
 501   } u;
 502
 503   __le32 fill[3];                       /* unused */
 504 };
 505
 506
 507 /* extended attributes.
 508
 509    A file's EA info is stored as a list of (name,value) pairs.  It is
 510    usually in the fnode, but (if it's large) it is moved to a single
 511    sector run outside the fnode, or to multiple runs with an anode tree
 512    that points to them.
 513
 514    The value of a single EA is stored along with the name, or (if large)
 515    it is moved to a single sector run, or multiple runs pointed to by an
 516    anode tree, pointed to by the value field of the (name,value) pair.
 517
 518    Flags in the EA tell whether the value is immediate, in a single sector
 519    run, or in multiple runs.  Flags in the fnode tell whether the EA list
 520    is immediate, in a single run, or in multiple runs. */
 521
 522 enum {EA_indirect = 1, EA_anode = 2, EA_needea = 128 };
 523 struct extended_attribute
 524 {
 525   u8 flags;                             /* bit 0 set -> value gives sector number
 526                                            where real value starts */
 527                                         /* bit 1 set -> sector is an anode
 528                                            that points to fragmented value */
 529                                         /* bit 7 set -> required ea */
 530   u8 namelen;                           /* length of name, bytes */
 531   u8 valuelen_lo;                       /* length of value, bytes */
 532   u8 valuelen_hi;                       /* length of value, bytes */
 533   u8 name[];
 534   /*
 535     u8 name[namelen];                   ascii attrib name
 536     u8 nul;                             terminating '\0', not counted
 537     u8 value[valuelen];                 value, arbitrary
 538       if this.flags & 1, valuelen is 8 and the value is
 539         u32 length;                     real length of value, bytes
 540         secno secno;                    sector address where it starts
 541       if this.anode, the above sector number is the root of an anode tree
 542         which points to the value.
 543   */
 544 };
 545
 546 static inline bool ea_indirect(struct extended_attribute *ea)
 547 {
 548         return ea->flags & EA_indirect;
 549 }
 550
 551 static inline bool ea_in_anode(struct extended_attribute *ea)
 552 {
 553         return ea->flags & EA_anode;
 554 }
 555
 556 /*
 557    Local Variables:
 558    comment-column: 40
 559    End:
 560 */