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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 
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 
44 {
45  u8 jmp[3];
46  u8 oem_id[8];
47  u8 bytes_per_sector[2]; /* 512 */
58  __le32 n_sectors_l; /* size of partition */
61  u8 sig_28h; /* 28h */
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 
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 
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 */
140  u8 dce_acls_active: 1;
142  u8 flag67: 2;
143 #else
144  u8 flag67: 2;
150  u8 install_dasd_limits: 1; /* HPFS386 flags */
151 #endif
152 
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 
204 {
205  __le32 magic; /* 4945 21f7 */
206  __le32 n_code_pages; /* number of pointers following */
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 
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 */
240  } code_page[3];
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
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 */
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) */
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 
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 
384 {
385  __le32 file_secno; /* subtree maps sectors < this */
386  __le32 down; /* pointer to subtree */
387 };
388 
389 enum {
390  BP_hbff = 1,
393  BP_internal = 0x80
394 };
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 
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 */
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 {
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 */
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 {
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 };
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 */