xref: /openbmc/linux/fs/hpfs/hpfs.h (revision e23feb16)
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 */
560