linux/fs/hpfs/hpfs.h
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   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
  28typedef u32 secno;                      /* sector number, partition relative */
  29
  30typedef secno dnode_secno;              /* sector number of a dnode */
  31typedef secno fnode_secno;              /* sector number of an fnode */
  32typedef secno anode_secno;              /* sector number of an anode */
  33
  34typedef 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
  43struct 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
  76struct 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
 110struct 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
 203struct 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
 225struct 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
 280struct 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
 302struct 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
 376struct 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
 383struct bplus_internal_node
 384{
 385  __le32 file_secno;                    /* subtree maps sectors < this  */
 386  __le32 down;                          /* pointer to subtree */
 387};
 388
 389enum {
 390        BP_hbff = 1,
 391        BP_fnode_parent = 0x20,
 392        BP_binary_search = 0x40,
 393        BP_internal = 0x80
 394};
 395struct 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
 417static inline bool bp_internal(struct bplus_header *bp)
 418{
 419        return bp->flags & BP_internal;
 420}
 421
 422static 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
 435enum {FNODE_anode = cpu_to_le16(2), FNODE_dir = cpu_to_le16(256)};
 436struct 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
 475static inline bool fnode_in_anode(struct fnode *p)
 476{
 477        return (p->flags & FNODE_anode) != 0;
 478}
 479
 480static 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
 490struct 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
 521enum {EA_indirect = 1, EA_anode = 2, EA_needea = 128 };
 522struct 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
 545static inline bool ea_indirect(struct extended_attribute *ea)
 546{
 547        return ea->flags & EA_indirect;
 548}
 549
 550static 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*/
 560
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