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*/
1 /*
2 * linux/fs/hpfs/hpfs_fs.c
3 * read-only HPFS
4 * version 1.0
5 *
6 * Chris Smith 1993
7 *
8 * Sources & references:
9 * Duncan, _Design ... of HPFS_, MSSJ 4(5) (C) 1989 Microsoft Corp
10 * linux/fs/minix Copyright (C) 1991, 1992, 1993 Linus Torvalds
11 * linux/fs/msdos Written 1992, 1993 by Werner Almesberger
12 * linux/fs/isofs Copyright (C) 1991 Eric Youngdale
13 */
14
15 #include <linux/fs.h>
16 #include <linux/hpfs_fs.h>
17 #include <linux/errno.h>
18 #include <linux/malloc.h>
19 #include <linux/sched.h>
20 #include <linux/locks.h>
21 #include <linux/stat.h>
22 #include <linux/string.h>
23 #include <asm/bitops.h>
24 #include <asm/segment.h>
25
26 #include "hpfs.h"
27
28 /*
29 * HPFS is a mixture of 512-byte blocks and 2048-byte blocks. The 2k blocks
30 * are used for directories and bitmaps. For bmap to work, we must run the
31 * file system with 512-byte blocks. The 2k blocks are assembled in buffers
32 * obtained from kmalloc.
33 *
34 * For a file's i-number we use the sector number of its fnode, coded.
35 * (Directory ino's are even, file ino's are odd, and ino >> 1 is the
36 * sector address of the fnode. This is a hack to allow lookup() to
37 * tell read_inode() whether it is necessary to read the fnode.)
38 *
39 * The map_xxx routines all read something into a buffer and return a
40 * pointer somewhere in the buffer. The caller must do the brelse.
41 * The other routines are balanced.
42 *
43 * For details on the data structures see hpfs.h and the Duncan paper.
44 *
45 * Overview
46 *
47 * [ The names of these data structures, except fnode, are not Microsoft's
48 * or IBM's. I don't know what names they use. The semantics described
49 * here are those of this implementation, and any coincidence between it
50 * and real HPFS is to be hoped for but not guaranteed by me, and
51 * certainly not guaranteed by MS or IBM. Who know nothing about this. ]
52 *
53 * [ Also, the following will make little sense if you haven't read the
54 * Duncan paper, which is excellent. ]
55 *
56 * HPFS is a tree. There are 3 kinds of nodes. A directory is a tree
57 * of dnodes, and a file's allocation info is a tree of sector runs
58 * stored in fnodes and anodes.
59 *
60 * The top pointer is in the super block, it points to the fnode of the
61 * root directory.
62 *
63 * The root directory -- all directories -- gives file names, dates &c,
64 * and fnode addresses. If the directory fits in one dnode, that's it,
65 * otherwise the top dnode points to other dnodes, forming a tree. A
66 * dnode tree (one directory) might look like
67 *
68 * ((a b c) d (e f g) h (i j) k l (m n o p))
69 *
70 * The subtrees appear between the files. Each dir entry contains, along
71 * with the name and fnode, a dnode pointer to the subtree that precedes it
72 * (if there is one; a flag tells that). The first entry in every directory
73 * is ^A^A, the "." entry for the directory itself. The last entry in every
74 * dnode is \377, a fake entry whose only valid fields are the bit marking
75 * it last and the down pointer to the subtree preceding it, if any.
76 *
77 * The "value" field of directory entries is an fnode address. The fnode
78 * tells where the sectors of the file are. The fnode for a subdirectory
79 * contains one pointer, to the root dnode of the subdirectory. The fnode
80 * for a data file contains, in effect, a tiny anode. (Most of the space
81 * in fnodes is for extended attributes.)
82 *
83 * anodes and the anode part of fnodes are trees of extents. An extent
84 * is a (length, disk address) pair, labeled with the file address being
85 * mapped. E.g.,
86 *
87 * (0: 3@1000 3: 1@2000 4: 2@10)
88 *
89 * means the file:disk sector map (0:1000 1:1001 2:1002 3:2000 4:10 5:11).
90 *
91 * There is space for 8 file:len@disk triples in an fnode, or for 40 in an
92 * anode. If this is insufficient, subtrees are used, as in
93 *
94 * (6: (0: 3@1000 3: 1@2000 4: 2@10) 12: (6: 3@8000 9: 1@9000 10: 2@20))
95 *
96 * The label on a subtree is the first address *after* that tree. The
97 * subtrees are always anodes. The label:subtree pairs require only
98 * two words each, so non-leaf subtrees have a different format; there
99 * is room for 12 label:subtree pairs in an fnode, or 60 in an anode.
100 *
101 * Within a directory, each dnode contains a pointer up to its parent
102 * dnode. The root dnode points up to the directory's fnode.
103 *
104 * Each fnode contains a pointer to the directory that contains it
105 * (to the fnode of the directory). So this pointer in a directory
106 * fnode is "..".
107 *
108 * On the disk, dnodes are all together in the center of the partition,
109 * and HPFS even manages to put all the dnodes for a single directory
110 * together, generally. fnodes are out with the data. anodes are seldom
111 * seen -- in fact noncontiguous files are seldom seen. I think this is
112 * partly the open() call that lets programs specify the length of an
113 * output file when they know it, and partly because HPFS.IFS really is
114 * very good at resisting fragmentation.
115 */
116
117 /* notation */
118
119 #define little_ushort(x) (*(unsigned short *) &(x))
120 typedef void nonconst;
121
122 /* super block ops */
123
124 static void hpfs_read_inode(struct inode *);
125 static void hpfs_put_super(struct super_block *);
126 static void hpfs_statfs(struct super_block *, struct statfs *);
127 static int hpfs_remount_fs(struct super_block *, int *);
128
129 static const struct super_operations hpfs_sops =
130 {
131 hpfs_read_inode, /* read_inode */
132 NULL, /* notify_change */
133 NULL, /* write_inode */
134 NULL, /* put_inode */
135 hpfs_put_super, /* put_super */
136 NULL, /* write_super */
137 hpfs_statfs, /* statfs */
138 hpfs_remount_fs, /* remount_fs */
139 };
140
141 /* file ops */
142
143 static int hpfs_file_read(struct inode *, struct file *, char *, int);
144 static secno hpfs_bmap(struct inode *, unsigned);
145
146 static const struct file_operations hpfs_file_ops =
147 {
148 NULL, /* lseek - default */
149 hpfs_file_read, /* read */
150 NULL, /* write */
151 NULL, /* readdir - bad */
152 NULL, /* select - default */
153 NULL, /* ioctl - default */
154 generic_mmap, /* mmap */
155 NULL, /* no special open is needed */
156 NULL, /* release */
157 file_fsync, /* fsync */
158 };
159
160 static const struct inode_operations hpfs_file_iops =
161 {
162 (nonconst *) & hpfs_file_ops, /* default file operations */
163 NULL, /* create */
164 NULL, /* lookup */
165 NULL, /* link */
166 NULL, /* unlink */
167 NULL, /* symlink */
168 NULL, /* mkdir */
169 NULL, /* rmdir */
170 NULL, /* mknod */
171 NULL, /* rename */
172 NULL, /* readlink */
173 NULL, /* follow_link */
174 (int (*)(struct inode *, int))
175 &hpfs_bmap, /* bmap */
176 NULL, /* truncate */
177 NULL, /* permission */
178 };
179
180 /* directory ops */
181
182 static int hpfs_dir_read(struct inode *inode, struct file *filp,
183 char *buf, int count);
184 static int hpfs_readdir(struct inode *inode, struct file *filp,
185 struct dirent *dirent, int count);
186 static int hpfs_lookup(struct inode *, const char *, int, struct inode **);
187
188 static const struct file_operations hpfs_dir_ops =
189 {
190 NULL, /* lseek - default */
191 hpfs_dir_read, /* read */
192 NULL, /* write - bad */
193 hpfs_readdir, /* readdir */
194 NULL, /* select - default */
195 NULL, /* ioctl - default */
196 NULL, /* mmap */
197 NULL, /* no special open code */
198 NULL, /* no special release code */
199 file_fsync, /* fsync */
200 };
201
202 static const struct inode_operations hpfs_dir_iops =
203 {
204 (nonconst *) & hpfs_dir_ops, /* default directory file ops */
205 NULL, /* create */
206 hpfs_lookup, /* lookup */
207 NULL, /* link */
208 NULL, /* unlink */
209 NULL, /* symlink */
210 NULL, /* mkdir */
211 NULL, /* rmdir */
212 NULL, /* mknod */
213 NULL, /* rename */
214 NULL, /* readlink */
215 NULL, /* follow_link */
216 NULL, /* bmap */
217 NULL, /* truncate */
218 NULL, /* permission */
219 };
220
221 /* Four 512-byte buffers and the 2k block obtained by concatenating them */
222
223 struct quad_buffer_head {
224 struct buffer_head *bh[4];
225 void *data;
226 };
227
228 /* forwards */
229
230 static int parse_opts(char *opts, uid_t *uid, gid_t *gid, umode_t *umask,
231 int *lowercase, int *conv);
232 static int check_warn(int not_ok,
233 const char *p1, const char *p2, const char *p3);
234 static int zerop(void *addr, unsigned len);
235 static void count_dnodes(struct inode *inode, dnode_secno dno,
236 unsigned *n_dnodes, unsigned *n_subdirs);
237 static unsigned count_bitmap(struct super_block *s);
238 static unsigned count_one_bitmap(dev_t dev, secno secno);
239 static secno bplus_lookup(struct inode *inode, struct bplus_header *b,
240 secno file_secno, struct buffer_head **bhp);
241 static struct hpfs_dirent *map_dirent(struct inode *inode, dnode_secno dno,
242 const unsigned char *name, unsigned len,
243 struct quad_buffer_head *qbh);
244 static struct hpfs_dirent *map_pos_dirent(struct inode *inode, off_t *posp,
245 struct quad_buffer_head *qbh);
246 static void write_one_dirent(struct dirent *dirent, const unsigned char *name,
247 unsigned namelen, ino_t ino, int lowercase);
248 static dnode_secno dir_subdno(struct inode *inode, unsigned pos);
249 static struct hpfs_dirent *map_nth_dirent(dev_t dev, dnode_secno dno,
250 int n,
251 struct quad_buffer_head *qbh);
252 static unsigned choose_conv(unsigned char *p, unsigned len);
253 static unsigned convcpy_tofs(unsigned char *out, unsigned char *in,
254 unsigned len);
255 static dnode_secno fnode_dno(dev_t dev, ino_t ino);
256 static struct fnode *map_fnode(dev_t dev, ino_t ino,
257 struct buffer_head **bhp);
258 static struct anode *map_anode(dev_t dev, unsigned secno,
259 struct buffer_head **bhp);
260 static struct dnode *map_dnode(dev_t dev, unsigned secno,
261 struct quad_buffer_head *qbh);
262 static void *map_sector(dev_t dev, unsigned secno, struct buffer_head **bhp);
263 static void *map_4sectors(dev_t dev, unsigned secno,
264 struct quad_buffer_head *qbh);
265 static void brelse4(struct quad_buffer_head *qbh);
266
267 /*
268 * make inode number for a file
269 */
270
271 static inline ino_t file_ino(fnode_secno secno)
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*/
272 {
273 return secno << 1 | 1;
274 }
275
276 /*
277 * make inode number for a directory
278 */
279
280 static inline ino_t dir_ino(fnode_secno secno)
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*/
281 {
282 return secno << 1;
283 }
284
285 /*
286 * get fnode address from an inode number
287 */
288
289 static inline fnode_secno ino_secno(ino_t ino)
/* */
290 {
291 return ino >> 1;
292 }
293
294 /*
295 * test for directory's inode number
296 */
297
298 static inline int ino_is_dir(ino_t ino)
/* */
299 {
300 return (ino & 1) == 0;
301 }
302
303 /*
304 * conv= options
305 */
306
307 #define CONV_BINARY 0 /* no conversion */
308 #define CONV_TEXT 1 /* crlf->newline */
309 #define CONV_AUTO 2 /* decide based on file contents */
310
311 /*
312 * local time (HPFS) to GMT (Unix)
313 */
314
315 static inline time_t local_to_gmt(time_t t)
/* */
316 {
317 extern struct timezone sys_tz;
318 return t + sys_tz.tz_minuteswest * 60;
319 }
320
321 /* super block ops */
322
323 /*
324 * mount. This gets one thing, the root directory inode. It does a
325 * bunch of guessed-at consistency checks.
326 */
327
328 struct super_block *hpfs_read_super(struct super_block *s,
/* */
329 void *options, int silent)
330 {
331 struct hpfs_boot_block *bootblock;
332 struct hpfs_super_block *superblock;
333 struct hpfs_spare_block *spareblock;
334 struct hpfs_dirent *de;
335 struct buffer_head *bh0, *bh1, *bh2;
336 struct quad_buffer_head qbh;
337 dnode_secno root_dno;
338 dev_t dev;
339 uid_t uid;
340 gid_t gid;
341 umode_t umask;
342 int lowercase;
343 int conv;
344 int dubious;
345
346 /*
347 * Get the mount options
348 */
349
350 if (!parse_opts(options, &uid, &gid, &umask, &lowercase, &conv)) {
351 printk("HPFS: syntax error in mount options. Not mounted.\n");
352 s->s_dev = 0;
353 return 0;
354 }
355
356 /*
357 * Fill in the super block struct
358 */
359
360 lock_super(s);
361 dev = s->s_dev;
362 set_blocksize(dev, 512);
363
364 /*
365 * fetch sectors 0, 16, 17
366 */
367
368 bootblock = map_sector(dev, 0, &bh0);
369 if (!bootblock)
370 goto bail;
371
372 superblock = map_sector(dev, 16, &bh1);
373 if (!superblock)
374 goto bail0;
375
376 spareblock = map_sector(dev, 17, &bh2);
377 if (!spareblock)
378 goto bail1;
379
380 /*
381 * Check that this fs looks enough like a known one that we can find
382 * and read the root directory.
383 */
384
385 if (bootblock->magic != 0xaa55
386 || superblock->magic != SB_MAGIC
387 || spareblock->magic != SP_MAGIC
388 || bootblock->sig_28h != 0x28
389 || memcmp(&bootblock->sig_hpfs, "HPFS ", 8)
390 || little_ushort(bootblock->bytes_per_sector) != 512) {
391 printk("HPFS: hpfs_read_super: Not HPFS\n");
392 goto bail2;
393 }
394
395 /*
396 * Check for inconsistencies -- possibly wrong guesses here, possibly
397 * filesystem problems.
398 */
399
400 dubious = 0;
401
402 dubious |= check_warn(spareblock->dirty != 0,
403 "`Improperly stopped'", "flag is set", "run CHKDSK");
404 dubious |= check_warn(spareblock->n_spares_used != 0,
405 "Spare blocks", "may be in use", "run CHKDSK");
406
407 /*
408 * Above errors mean we could get wrong answers if we proceed,
409 * so don't
410 */
411
412 if (dubious)
413 goto bail2;
414
415 dubious |= check_warn((spareblock->n_dnode_spares !=
416 spareblock->n_dnode_spares_free),
417 "Spare dnodes", "may be in use", "run CHKDSK");
418 dubious |= check_warn(superblock->zero1 != 0,
419 "#1", "unknown word nonzero", "investigate");
420 dubious |= check_warn(superblock->zero3 != 0,
421 "#3", "unknown word nonzero", "investigate");
422 dubious |= check_warn(superblock->zero4 != 0,
423 "#4", "unknown word nonzero", "investigate");
424 dubious |= check_warn(!zerop(superblock->zero5,
425 sizeof superblock->zero5),
426 "#5", "unknown word nonzero", "investigate");
427 dubious |= check_warn(!zerop(superblock->zero6,
428 sizeof superblock->zero6),
429 "#6", "unknown word nonzero", "investigate");
430
431 if (dubious)
432 printk("HPFS: Proceeding, but operation may be unreliable\n");
433
434 /*
435 * set fs read only
436 */
437
438 s->s_flags |= MS_RDONLY;
439
440 /*
441 * fill in standard stuff
442 */
443
444 s->s_magic = HPFS_SUPER_MAGIC;
445 s->s_blocksize = 512;
446 s->s_blocksize_bits = 9;
447 s->s_op = (struct super_operations *) &hpfs_sops;
448
449 /*
450 * fill in hpfs stuff
451 */
452
453 s->s_hpfs_root = dir_ino(superblock->root);
454 s->s_hpfs_fs_size = superblock->n_sectors;
455 s->s_hpfs_dirband_size = superblock->n_dir_band / 4;
456 s->s_hpfs_dmap = superblock->dir_band_bitmap;
457 s->s_hpfs_bitmaps = superblock->bitmaps;
458 s->s_hpfs_uid = uid;
459 s->s_hpfs_gid = gid;
460 s->s_hpfs_mode = 0777 & ~umask;
461 s->s_hpfs_n_free = -1;
462 s->s_hpfs_n_free_dnodes = -1;
463 s->s_hpfs_lowercase = lowercase;
464 s->s_hpfs_conv = conv;
465
466 /*
467 * done with the low blocks
468 */
469
470 brelse(bh2);
471 brelse(bh1);
472 brelse(bh0);
473
474 /*
475 * all set. try it out.
476 */
477
478 s->s_mounted = iget(s, s->s_hpfs_root);
479 unlock_super(s);
480
481 if (!s->s_mounted) {
482 printk("HPFS: hpfs_read_super: inode get failed\n");
483 s->s_dev = 0;
484 return 0;
485 }
486
487 /*
488 * find the root directory's . pointer & finish filling in the inode
489 */
490
491 root_dno = fnode_dno(dev, s->s_hpfs_root);
492 if (root_dno)
493 de = map_dirent(s->s_mounted, root_dno, "\001\001", 2, &qbh);
494 if (!root_dno || !de) {
495 printk("HPFS: "
496 "hpfs_read_super: root dir isn't in the root dir\n");
497 s->s_dev = 0;
498 return 0;
499 }
500
501 s->s_mounted->i_atime = local_to_gmt(de->read_date);
502 s->s_mounted->i_mtime = local_to_gmt(de->write_date);
503 s->s_mounted->i_ctime = local_to_gmt(de->creation_date);
504
505 brelse4(&qbh);
506 return s;
507
508 bail2:
509 brelse(bh2);
510 bail1:
511 brelse(bh1);
512 bail0:
513 brelse(bh0);
514 bail:
515 s->s_dev = 0;
516 unlock_super(s);
517 return 0;
518 }
519
520 static int check_warn(int not_ok,
/* */
521 const char *p1, const char *p2, const char *p3)
522 {
523 if (not_ok)
524 printk("HPFS: %s %s. Please %s\n", p1, p2, p3);
525 return not_ok;
526 }
527
528 static int zerop(void *addr, unsigned len)
/* */
529 {
530 unsigned char *p = addr;
531 return p[0] == 0 && memcmp(p, p + 1, len - 1) == 0;
532 }
533
534 /*
535 * A tiny parser for option strings, stolen from dosfs.
536 */
537
538 static int parse_opts(char *opts, uid_t *uid, gid_t *gid, umode_t *umask,
/* */
539 int *lowercase, int *conv)
540 {
541 char *p, *rhs;
542
543 *uid = current->uid;
544 *gid = current->gid;
545 *umask = current->umask;
546 *lowercase = 1;
547 *conv = CONV_BINARY;
548
549 if (!opts)
550 return 1;
551
552 for (p = strtok(opts, ","); p != 0; p = strtok(0, ",")) {
553 if ((rhs = strchr(p, '=')) != 0)
554 *rhs++ = '\0';
555 if (!strcmp(p, "uid")) {
556 if (!rhs || !*rhs)
557 return 0;
558 *uid = simple_strtoul(rhs, &rhs, 0);
559 if (*rhs)
560 return 0;
561 }
562 else if (!strcmp(p, "gid")) {
563 if (!rhs || !*rhs)
564 return 0;
565 *gid = simple_strtoul(rhs, &rhs, 0);
566 if (*rhs)
567 return 0;
568 }
569 else if (!strcmp(p, "umask")) {
570 if (!rhs || !*rhs)
571 return 0;
572 *umask = simple_strtoul(rhs, &rhs, 8);
573 if (*rhs)
574 return 0;
575 }
576 else if (!strcmp(p, "case")) {
577 if (!strcmp(rhs, "lower"))
578 *lowercase = 1;
579 else if (!strcmp(rhs, "asis"))
580 *lowercase = 0;
581 else
582 return 0;
583 }
584 else if (!strcmp(p, "conv")) {
585 if (!strcmp(rhs, "binary"))
586 *conv = CONV_BINARY;
587 else if (!strcmp(rhs, "text"))
588 *conv = CONV_TEXT;
589 else if (!strcmp(rhs, "auto"))
590 *conv = CONV_AUTO;
591 else
592 return 0;
593 }
594 else
595 return 0;
596 }
597
598 return 1;
599 }
600
601 /*
602 * read_inode. This is called with exclusive access to a new inode that
603 * has only (i_dev,i_ino) set. It is responsible for filling in the rest.
604 * We leave the dates blank, to be filled in from the dir entry.
605 *
606 * NOTE that there must be no sleeping from the return in this routine
607 * until lookup() finishes filling in the inode, otherwise the partly
608 * completed inode would be visible during the sleep.
609 *
610 * It is done in this strange and sinful way because the alternative
611 * is to read the fnode, find the dir pointer in it, read that fnode
612 * to get the dnode pointer, search through that whole directory for
613 * the ino we're reading, and get the dates. It works that way, but
614 * ls sounds like fsck.
615 */
616
617 static void hpfs_read_inode(struct inode *inode)
/* */
618 {
619 struct super_block *s = inode->i_sb;
620
621 /* be ready to bail out */
622
623 inode->i_op = 0;
624 inode->i_mode = 0;
625
626 if (inode->i_ino == 0
627 || ino_secno(inode->i_ino) >= inode->i_sb->s_hpfs_fs_size) {
628 printk("HPFS: read_inode: bad ino\n");
629 return;
630 }
631
632 /*
633 * canned stuff
634 */
635
636 inode->i_uid = s->s_hpfs_uid;
637 inode->i_gid = s->s_hpfs_gid;
638 inode->i_mode = s->s_hpfs_mode;
639 inode->i_hpfs_conv = s->s_hpfs_conv;
640
641 inode->i_hpfs_dno = 0;
642 inode->i_hpfs_n_secs = 0;
643 inode->i_hpfs_file_sec = 0;
644 inode->i_hpfs_disk_sec = 0;
645 inode->i_hpfs_dpos = 0;
646 inode->i_hpfs_dsubdno = 0;
647
648 /*
649 * figure out whether we are looking at a directory or a file
650 */
651
652 if (ino_is_dir(inode->i_ino))
653 inode->i_mode |= S_IFDIR;
654 else {
655 inode->i_mode |= S_IFREG;
656 inode->i_mode &= ~0111;
657 }
658
659 /*
660 * these fields must be filled in from the dir entry, which we don't
661 * have but lookup does. It will fill them in before letting the
662 * inode out of its grasp.
663 */
664
665 inode->i_atime = 0;
666 inode->i_mtime = 0;
667 inode->i_ctime = 0;
668 inode->i_size = 0;
669
670 /*
671 * fill in the rest
672 */
673
674 if (S_ISREG(inode->i_mode)) {
675
676 inode->i_op = (struct inode_operations *) &hpfs_file_iops;
677 inode->i_nlink = 1;
678 inode->i_blksize = 512;
679
680 }
681 else {
682 unsigned n_dnodes, n_subdirs;
683 struct buffer_head *bh0;
684 struct fnode *fnode = map_fnode(inode->i_dev,
685 inode->i_ino, &bh0);
686
687 if (!fnode) {
688 printk("HPFS: read_inode: no fnode\n");
689 inode->i_mode = 0;
690 return;
691 }
692
693 inode->i_hpfs_parent_dir = dir_ino(fnode->up);
694 inode->i_hpfs_dno = fnode->u.external[0].disk_secno;
695
696 brelse(bh0);
697
698 n_dnodes = n_subdirs = 0;
699 count_dnodes(inode, inode->i_hpfs_dno, &n_dnodes, &n_subdirs);
700
701 inode->i_op = (struct inode_operations *) &hpfs_dir_iops;
702 inode->i_blksize = 512; /* 2048 here confuses ls & du & ... */
703 inode->i_blocks = 4 * n_dnodes;
704 inode->i_size = 512 * inode->i_blocks;
705 inode->i_nlink = 2 + n_subdirs;
706 }
707 }
708
709 /*
710 * unmount.
711 */
712
713 static void hpfs_put_super(struct super_block *s)
/* */
714 {
715 lock_super(s);
716 s->s_dev = 0;
717 unlock_super(s);
718 }
719
720 /*
721 * statfs. For free inode counts we report the count of dnodes in the
722 * directory band -- not exactly right but pretty analagous.
723 */
724
725 static void hpfs_statfs(struct super_block *s, struct statfs *buf)
/* */
726 {
727 /*
728 * count the bits in the bitmaps, unless we already have
729 */
730
731 if (s->s_hpfs_n_free == -1) {
732 s->s_hpfs_n_free = count_bitmap(s);
733 s->s_hpfs_n_free_dnodes =
734 count_one_bitmap(s->s_dev, s->s_hpfs_dmap);
735 }
736
737 /*
738 * fill in the user statfs struct
739 */
740
741 put_fs_long(s->s_magic, &buf->f_type);
742 put_fs_long(512, &buf->f_bsize);
743 put_fs_long(s->s_hpfs_fs_size, &buf->f_blocks);
744 put_fs_long(s->s_hpfs_n_free, &buf->f_bfree);
745 put_fs_long(s->s_hpfs_n_free, &buf->f_bavail);
746 put_fs_long(s->s_hpfs_dirband_size, &buf->f_files);
747 put_fs_long(s->s_hpfs_n_free_dnodes, &buf->f_ffree);
748 put_fs_long(254, &buf->f_namelen);
749 }
750
751 /*
752 * remount. Don't let read only be turned off.
753 */
754
755 static int hpfs_remount_fs(struct super_block *s, int *flags)
/* */
756 {
757 if (!(*flags & MS_RDONLY))
758 return -EINVAL;
759 return 0;
760 }
761
762 /*
763 * count the dnodes in a directory, and the subdirs.
764 */
765
766 static void count_dnodes(struct inode *inode, dnode_secno dno,
/* */
767 unsigned *n_dnodes, unsigned *n_subdirs)
768 {
769 struct quad_buffer_head qbh;
770 struct dnode *dnode;
771 struct hpfs_dirent *de;
772 struct hpfs_dirent *de_end;
773
774 dnode = map_dnode(inode->i_dev, dno, &qbh);
775 if (!dnode)
776 return;
777 de = dnode_first_de(dnode);
778 de_end = dnode_end_de(dnode);
779
780 (*n_dnodes)++;
781
782 for (; de < de_end; de = de_next_de(de)) {
783 if (de->down)
784 count_dnodes(inode, de_down_pointer(de),
785 n_dnodes, n_subdirs);
786 if (de->directory && !de->first)
787 (*n_subdirs)++;
788 if (de->last || de->length == 0)
789 break;
790 }
791
792 brelse4(&qbh);
793 }
794
795 /*
796 * count the bits in the free space bit maps
797 */
798
799 static unsigned count_bitmap(struct super_block *s)
/* */
800 {
801 unsigned n, count, n_bands;
802 secno *bitmaps;
803 struct quad_buffer_head qbh;
804
805 /*
806 * there is one bit map for each 16384 sectors
807 */
808 n_bands = (s->s_hpfs_fs_size + 0x3fff) >> 14;
809
810 /*
811 * their locations are given in an array pointed to by the super
812 * block
813 */
814 bitmaps = map_4sectors(s->s_dev, s->s_hpfs_bitmaps, &qbh);
815 if (!bitmaps)
816 return 0;
817
818 count = 0;
819
820 /*
821 * map each one and count the free sectors
822 */
823 for (n = 0; n < n_bands; n++)
824 if (bitmaps[n] == 0)
825 printk("HPFS: bit map pointer missing\n");
826 else
827 count += count_one_bitmap(s->s_dev, bitmaps[n]);
828
829 brelse4(&qbh);
830 return count;
831 }
832
833 /*
834 * Read in one bit map, count the bits, return the count.
835 */
836
837 static unsigned count_one_bitmap(dev_t dev, secno secno)
/* */
838 {
839 struct quad_buffer_head qbh;
840 char *bits;
841 unsigned i, count;
842
843 bits = map_4sectors(dev, secno, &qbh);
844 if (!bits)
845 return 0;
846
847 count = 0;
848
849 for (i = 0; i < 8 * 2048; i++)
850 count += (test_bit(i, bits) != 0);
851 brelse4(&qbh);
852
853 return count;
854 }
855
856 /* file ops */
857
858 /*
859 * read. Read the bytes, put them in buf, return the count.
860 */
861
862 static int hpfs_file_read(struct inode *inode, struct file *filp,
/* */
863 char *buf, int count)
864 {
865 unsigned q, r, n, n0;
866 struct buffer_head *bh;
867 char *block;
868 char *start;
869
870 if (inode == 0 || !S_ISREG(inode->i_mode))
871 return -EINVAL;
872
873 /*
874 * truncate count at EOF
875 */
876 if (count > inode->i_size - filp->f_pos)
877 count = inode->i_size - filp->f_pos;
878
879 start = buf;
880 while (count > 0) {
881 /*
882 * get file sector number, offset in sector, length to end of
883 * sector
884 */
885 q = filp->f_pos >> 9;
886 r = filp->f_pos & 511;
887 n = 512 - r;
888
889 /*
890 * get length to copy to user buffer
891 */
892 if (n > count)
893 n = count;
894
895 /*
896 * read the sector, copy to user
897 */
898 block = map_sector(inode->i_dev, hpfs_bmap(inode, q), &bh);
899 if (!block)
900 return -EIO;
901
902 /*
903 * but first decide if it has \r\n, if the mount option said
904 * to do that
905 */
906 if (inode->i_hpfs_conv == CONV_AUTO)
907 inode->i_hpfs_conv = choose_conv(block + r, n);
908
909 if (inode->i_hpfs_conv == CONV_BINARY) {
910 /*
911 * regular copy, output length is same as input
912 * length
913 */
914 memcpy_tofs(buf, block + r, n);
915 n0 = n;
916 }
917 else {
918 /*
919 * squeeze out \r, output length varies
920 */
921 n0 = convcpy_tofs(buf, block + r, n);
922 if (count > inode->i_size - filp->f_pos - n + n0)
923 count = inode->i_size - filp->f_pos - n + n0;
924 }
925
926 brelse(bh);
927
928 /*
929 * advance input n bytes, output n0 bytes
930 */
931 filp->f_pos += n;
932 buf += n0;
933 count -= n0;
934 }
935
936 return buf - start;
937 }
938
939 /*
940 * This routine implements conv=auto. Return CONV_BINARY or CONV_TEXT.
941 */
942
943 static unsigned choose_conv(unsigned char *p, unsigned len)
/* */
944 {
945 unsigned tvote, bvote;
946 unsigned c;
947
948 tvote = bvote = 0;
949
950 while (len--) {
951 c = *p++;
952 if (c < ' ')
953 if (c == '\r' && len && *p == '\n')
954 tvote += 10;
955 else if (c == '\t' || c == '\n');
956 else
957 bvote += 5;
958 else if (c < '\177')
959 tvote++;
960 else
961 bvote += 5;
962 }
963
964 if (tvote > bvote)
965 return CONV_TEXT;
966 else
967 return CONV_BINARY;
968 }
969
970 /*
971 * This routine implements conv=text. :s/crlf/nl/
972 */
973
974 static unsigned convcpy_tofs(unsigned char *out, unsigned char *in,
/* */
975 unsigned len)
976 {
977 unsigned char *start = out;
978
979 while (len--) {
980 unsigned c = *in++;
981 if (c == '\r' && (len == 0 || *in == '\n'));
982 else
983 put_fs_byte(c, out++);
984 }
985
986 return out - start;
987 }
988
989 /*
990 * Return the disk sector number containing a file sector.
991 */
992
993 static secno hpfs_bmap(struct inode *inode, unsigned file_secno)
/* */
994 {
995 unsigned n, disk_secno;
996 struct fnode *fnode;
997 struct buffer_head *bh;
998
999 /*
1000 * There is one sector run cached in the inode. See if the sector is
1001 * in it.
1002 */
1003
1004 n = file_secno - inode->i_hpfs_file_sec;
1005 if (n < inode->i_hpfs_n_secs)
1006 return inode->i_hpfs_disk_sec + n;
1007
1008 /*
1009 * No, read the fnode and go find the sector.
1010 */
1011
1012 else {
1013 fnode = map_fnode(inode->i_dev, inode->i_ino, &bh);
1014 if (!fnode)
1015 return 0;
1016 disk_secno = bplus_lookup(inode, &fnode->btree,
1017 file_secno, &bh);
1018 brelse(bh);
1019 return disk_secno;
1020 }
1021 }
1022
1023 /*
1024 * Search allocation tree *b for the given file sector number and return
1025 * the disk sector number. Buffer *bhp has the tree in it, and can be
1026 * reused for subtrees when access to *b is no longer needed.
1027 * *bhp is busy on entry and exit.
1028 */
1029
1030 static secno bplus_lookup(struct inode *inode, struct bplus_header *b,
/* */
1031 secno file_secno, struct buffer_head **bhp)
1032 {
1033 int i;
1034
1035 /*
1036 * A leaf-level tree gives a list of sector runs. Find the one
1037 * containing the file sector we want, cache the map info in the
1038 * inode for later, and return the corresponding disk sector.
1039 */
1040
1041 if (!b->internal) {
1042 struct bplus_leaf_node *n = b->u.external;
1043 for (i = 0; i < b->n_used_nodes; i++) {
1044 unsigned t = file_secno - n[i].file_secno;
1045 if (t < n[i].length) {
1046 inode->i_hpfs_file_sec = n[i].file_secno;
1047 inode->i_hpfs_disk_sec = n[i].disk_secno;
1048 inode->i_hpfs_n_secs = n[i].length;
1049 return n[i].disk_secno + t;
1050 }
1051 }
1052 }
1053
1054 /*
1055 * A non-leaf tree gives a list of subtrees. Find the one containing
1056 * the file sector we want, read it in, and recurse to search it.
1057 */
1058
1059 else {
1060 struct bplus_internal_node *n = b->u.internal;
1061 for (i = 0; i < b->n_used_nodes; i++) {
1062 if (file_secno < n[i].file_secno) {
1063 struct anode *anode;
1064 anode_secno ano = n[i].down;
1065 brelse(*bhp);
1066 anode = map_anode(inode->i_dev, ano, bhp);
1067 if (!anode)
1068 break;
1069 return bplus_lookup(inode, &anode->btree,
1070 file_secno, bhp);
1071 }
1072 }
1073 }
1074
1075 /*
1076 * If we get here there was a hole in the file. As far as I know we
1077 * never do get here, but falling off the end would be indelicate. So
1078 * return a pointer to a handy all-zero sector. This is not a
1079 * reasonable way to handle files with holes if they really do
1080 * happen.
1081 */
1082
1083 printk("HPFS: bplus_lookup: sector not found\n");
1084 return 15;
1085 }
1086
1087 /* directory ops */
1088
1089 /*
1090 * lookup. Search the specified directory for the specified name, set
1091 * *result to the corresponding inode.
1092 *
1093 * lookup uses the inode number to tell read_inode whether it is reading
1094 * the inode of a directory or a file -- file ino's are odd, directory
1095 * ino's are even. read_inode avoids i/o for file inodes; everything
1096 * needed is up here in the directory. (And file fnodes are out in
1097 * the boondocks.)
1098 */
1099
1100 static int hpfs_lookup(struct inode *dir, const char *name, int len,
/* */
1101 struct inode **result)
1102 {
1103 struct quad_buffer_head qbh;
1104 struct hpfs_dirent *de;
1105 struct inode *inode;
1106 ino_t ino;
1107
1108 /* In case of madness */
1109
1110 *result = 0;
1111 if (dir == 0)
1112 return -ENOENT;
1113 if (!S_ISDIR(dir->i_mode))
1114 goto bail;
1115
1116 /*
1117 * Read in the directory entry. "." is there under the name ^A^A .
1118 * Always read the dir even for . and .. in case we need the dates.
1119 */
1120
1121 if (name[0] == '.' && len == 1)
1122 de = map_dirent(dir, dir->i_hpfs_dno, "\001\001", 2, &qbh);
1123 else if (name[0] == '.' && name[1] == '.' && len == 2)
1124 de = map_dirent(dir,
1125 fnode_dno(dir->i_dev, dir->i_hpfs_parent_dir),
1126 "\001\001", 2, &qbh);
1127 else
1128 de = map_dirent(dir, dir->i_hpfs_dno, name, len, &qbh);
1129
1130 /*
1131 * This is not really a bailout, just means file not found.
1132 */
1133
1134 if (!de)
1135 goto bail;
1136
1137 /*
1138 * Get inode number, what we're after.
1139 */
1140
1141 if (de->directory)
1142 ino = dir_ino(de->fnode);
1143 else
1144 ino = file_ino(de->fnode);
1145
1146 /*
1147 * Go find or make an inode.
1148 */
1149
1150 if (!(inode = iget(dir->i_sb, ino)))
1151 goto bail1;
1152
1153 /*
1154 * Fill in the info from the directory if this is a newly created
1155 * inode.
1156 */
1157
1158 if (!inode->i_atime) {
1159 inode->i_atime = local_to_gmt(de->read_date);
1160 inode->i_mtime = local_to_gmt(de->write_date);
1161 inode->i_ctime = local_to_gmt(de->creation_date);
1162 if (de->read_only)
1163 inode->i_mode &= ~0222;
1164 if (!de->directory) {
1165 inode->i_size = de->file_size;
1166 /*
1167 * i_blocks should count the fnode and any anodes.
1168 * We count 1 for the fnode and don't bother about
1169 * anodes -- the disk heads are on the directory band
1170 * and we want them to stay there.
1171 */
1172 inode->i_blocks = 1 + ((inode->i_size + 511) >> 9);
1173 }
1174 }
1175
1176 brelse4(&qbh);
1177
1178 /*
1179 * Made it.
1180 */
1181
1182 *result = inode;
1183 iput(dir);
1184 return 0;
1185
1186 /*
1187 * Didn't.
1188 */
1189 bail1:
1190 brelse4(&qbh);
1191 bail:
1192 iput(dir);
1193 return -ENOENT;
1194 }
1195
1196 /*
1197 * Compare two counted strings ignoring case.
1198 * HPFS directory order sorts letters as if they're upper case.
1199 */
1200
1201 static inline int memcasecmp(const unsigned char *s1, const unsigned char *s2,
/* */
1202 unsigned n)
1203 {
1204 int t;
1205
1206 if (n != 0)
1207 do {
1208 unsigned c1 = *s1++;
1209 unsigned c2 = *s2++;
1210 if (c1 - 'a' < 26)
1211 c1 -= 040;
1212 if (c2 - 'a' < 26)
1213 c2 -= 040;
1214 if ((t = c1 - c2) != 0)
1215 return t;
1216 } while (--n != 0);
1217
1218 return 0;
1219 }
1220
1221 /*
1222 * Search a directory for the given name, return a pointer to its dir entry
1223 * and a pointer to the buffer containing it.
1224 */
1225
1226 static struct hpfs_dirent *map_dirent(struct inode *inode, dnode_secno dno,
/* */
1227 const unsigned char *name, unsigned len,
1228 struct quad_buffer_head *qbh)
1229 {
1230 struct dnode *dnode;
1231 struct hpfs_dirent *de;
1232 struct hpfs_dirent *de_end;
1233 int t, l;
1234
1235 /*
1236 * read the dnode at the root of our subtree
1237 */
1238 dnode = map_dnode(inode->i_dev, dno, qbh);
1239 if (!dnode)
1240 return 0;
1241
1242 /*
1243 * get pointers to start and end+1 of dir entries
1244 */
1245 de = dnode_first_de(dnode);
1246 de_end = dnode_end_de(dnode);
1247
1248 /*
1249 * look through the entries for the name we're after
1250 */
1251 for ( ; de < de_end; de = de_next_de(de)) {
1252
1253 /*
1254 * compare names
1255 */
1256 l = len < de->namelen ? len : de->namelen;
1257 t = memcasecmp(name, de->name, l);
1258
1259 /*
1260 * initial substring matches, compare lengths
1261 */
1262 if (t == 0) {
1263 t = len - de->namelen;
1264 /* bingo */
1265 if (t == 0)
1266 return de;
1267 }
1268
1269 /*
1270 * wanted name .lt. dir name => not present.
1271 */
1272 if (t < 0) {
1273 /*
1274 * if there is a subtree, search it.
1275 */
1276 if (de->down) {
1277 dnode_secno sub_dno = de_down_pointer(de);
1278 brelse4(qbh);
1279 return map_dirent(inode, sub_dno,
1280 name, len, qbh);
1281 }
1282 else
1283 break;
1284 }
1285
1286 /*
1287 * de->last is set on the last name in the dnode (it's always
1288 * a "\377" pseudo entry). de->length == 0 means we're about
1289 * to infinite loop. This test does nothing in a well-formed
1290 * dnode.
1291 */
1292 if (de->last || de->length == 0)
1293 break;
1294 }
1295
1296 /*
1297 * name not found.
1298 */
1299
1300 return 0;
1301 }
1302
1303 /*
1304 * readdir. Return exactly 1 dirent. (I tried and tried, but currently
1305 * the interface with libc just does not permit more than 1. If it gets
1306 * fixed, throw this out and just walk the tree and write records into
1307 * the user buffer.)
1308 *
1309 * We keep track of our position in the dnode tree with a sort of
1310 * dewey-decimal record of subtree locations. Like so:
1311 *
1312 * (1 (1.1 1.2 1.3) 2 3 (3.1 (3.1.1 3.1.2) 3.2 3.3 (3.3.1)) 4)
1313 *
1314 * Subtrees appear after their file, out of lexical order,
1315 * which would be before their file. It's easier.
1316 *
1317 * A directory can't hold more than 56 files, so 6 bits are used for
1318 * position numbers. If the tree is so deep that the position encoding
1319 * doesn't fit, I'm sure something absolutely fascinating happens.
1320 *
1321 * The actual sequence of f_pos values is
1322 * 0 => . -1 => .. 1 1.1 ... 8.9 9 => files -2 => eof
1323 *
1324 * The directory inode caches one position-to-dnode correspondence so
1325 * we won't have to repeatedly scan the top levels of the tree.
1326 */
1327
1328 static int hpfs_readdir(struct inode *inode, struct file *filp,
/* */
1329 struct dirent *dirent, int likely_story)
1330 {
1331 struct quad_buffer_head qbh;
1332 struct hpfs_dirent *de;
1333 int namelen, lc;
1334 ino_t ino;
1335
1336 if (inode == 0
1337 || inode->i_sb == 0
1338 || !S_ISDIR(inode->i_mode))
1339 return -EBADF;
1340
1341 lc = inode->i_sb->s_hpfs_lowercase;
1342
1343 switch (filp->f_pos) {
1344 case 0:
1345 write_one_dirent(dirent, ".", 1, inode->i_ino, lc);
1346 filp->f_pos = -1;
1347 return 1;
1348
1349 case -1:
1350 write_one_dirent(dirent, "..", 2,
1351 inode->i_hpfs_parent_dir, lc);
1352 filp->f_pos = 1;
1353 return 2;
1354
1355 case -2:
1356 return 0;
1357
1358 default:
1359 de = map_pos_dirent(inode, &filp->f_pos, &qbh);
1360 if (!de) {
1361 filp->f_pos = -2;
1362 return 0;
1363 }
1364
1365 namelen = de->namelen;
1366 if (de->directory)
1367 ino = dir_ino(de->fnode);
1368 else
1369 ino = file_ino(de->fnode);
1370 write_one_dirent(dirent, de->name, namelen, ino, lc);
1371 brelse4(&qbh);
1372
1373 return namelen;
1374 }
1375 }
1376
1377 /*
1378 * Send the given name and ino off to the user dirent struct at *dirent.
1379 * Blam it to lowercase if the mount option said to.
1380 *
1381 * Note that Linux d_reclen is the length of the file name, and has nothing
1382 * to do with the length of the dirent record.
1383 */
1384
1385 static void write_one_dirent(struct dirent *dirent, const unsigned char *name,
/* */
1386 unsigned namelen, ino_t ino, int lowercase)
1387 {
1388 unsigned n;
1389
1390 put_fs_long(ino, &dirent->d_ino);
1391 put_fs_word(namelen, &dirent->d_reclen);
1392
1393 if (lowercase)
1394 for (n = namelen; n != 0;) {
1395 unsigned t = name[--n];
1396 if (t - 'A' < 26)
1397 t += 040;
1398 put_fs_byte(t, &dirent->d_name[n]);
1399 }
1400 else
1401 memcpy_tofs(dirent->d_name, name, namelen);
1402
1403 put_fs_byte(0, &dirent->d_name[namelen]);
1404 }
1405
1406 /*
1407 * Map the dir entry at subtree coordinates given by *posp, and
1408 * increment *posp to point to the following dir entry.
1409 */
1410
1411 static struct hpfs_dirent *map_pos_dirent(struct inode *inode, off_t *posp,
/* */
1412 struct quad_buffer_head *qbh)
1413 {
1414 unsigned pos, q, r;
1415 dnode_secno dno;
1416 struct hpfs_dirent *de;
1417
1418 /*
1419 * Get the position code and split off the rightmost index r
1420 */
1421
1422 pos = *posp;
1423 q = pos >> 6;
1424 r = pos & 077;
1425
1426 /*
1427 * Get the sector address of the dnode
1428 * pointed to by the leading part q
1429 */
1430
1431 dno = dir_subdno(inode, q);
1432 if (!dno)
1433 return 0;
1434
1435 /*
1436 * Get the entry at index r in dnode q
1437 */
1438
1439 de = map_nth_dirent(inode->i_dev, dno, r, qbh);
1440
1441 /*
1442 * If none, we're out of files in this dnode. Ascend.
1443 */
1444
1445 if (!de) {
1446 if (q == 0)
1447 return 0;
1448 *posp = q + 1;
1449 return map_pos_dirent(inode, posp, qbh);
1450 }
1451
1452 /*
1453 * If a subtree is here, descend.
1454 */
1455
1456 if (de->down)
1457 *posp = pos << 6 | 1;
1458 else
1459 *posp = pos + 1;
1460
1461 /*
1462 * Don't return the ^A^A and \377 entries.
1463 */
1464
1465 if (de->first || de->last) {
1466 brelse4(qbh);
1467 return map_pos_dirent(inode, posp, qbh);
1468 }
1469 else
1470 return de;
1471 }
1472
1473 /*
1474 * Return the address of the dnode with subtree coordinates given by pos.
1475 */
1476
1477 static dnode_secno dir_subdno(struct inode *inode, unsigned pos)
/* */
1478 {
1479 struct hpfs_dirent *de;
1480 struct quad_buffer_head qbh;
1481
1482 /*
1483 * 0 is the root dnode
1484 */
1485
1486 if (pos == 0)
1487 return inode->i_hpfs_dno;
1488
1489 /*
1490 * we have one pos->dnode translation cached in the inode
1491 */
1492
1493 else if (pos == inode->i_hpfs_dpos)
1494 return inode->i_hpfs_dsubdno;
1495
1496 /*
1497 * otherwise go look
1498 */
1499
1500 else {
1501 unsigned q = pos >> 6;
1502 unsigned r = pos & 077;
1503 dnode_secno dno;
1504
1505 /*
1506 * dnode at position q
1507 */
1508 dno = dir_subdno(inode, q);
1509 if (dno == 0)
1510 return 0;
1511
1512 /*
1513 * entry at index r
1514 */
1515 de = map_nth_dirent(inode->i_dev, dno, r, &qbh);
1516 if (!de || !de->down)
1517 return 0;
1518
1519 /*
1520 * get the dnode down pointer
1521 */
1522 dno = de_down_pointer(de);
1523 brelse4(&qbh);
1524
1525 /*
1526 * cache it for next time
1527 */
1528 inode->i_hpfs_dpos = pos;
1529 inode->i_hpfs_dsubdno = dno;
1530 return dno;
1531 }
1532 }
1533
1534 /*
1535 * Return the dir entry at index n in dnode dno, or 0 if there isn't one
1536 */
1537
1538 static struct hpfs_dirent *map_nth_dirent(dev_t dev, dnode_secno dno,
/* */
1539 int n,
1540 struct quad_buffer_head *qbh)
1541 {
1542 int i;
1543 struct hpfs_dirent *de, *de_end;
1544 struct dnode *dnode = map_dnode(dev, dno, qbh);
1545
1546 de = dnode_first_de(dnode);
1547 de_end = dnode_end_de(dnode);
1548
1549 for (i = 1; de < de_end; i++, de = de_next_de(de)) {
1550 if (i == n)
1551 return de;
1552 if (de->last || de->length == 0)
1553 break;
1554 }
1555
1556 brelse4(qbh);
1557 return 0;
1558 }
1559
1560 static int hpfs_dir_read(struct inode *inode, struct file *filp,
/* */
1561 char *buf, int count)
1562 {
1563 return -EISDIR;
1564 }
1565
1566 /* Return the dnode pointer in a directory fnode */
1567
1568 static dnode_secno fnode_dno(dev_t dev, ino_t ino)
/* */
1569 {
1570 struct buffer_head *bh;
1571 struct fnode *fnode;
1572 dnode_secno dno;
1573
1574 fnode = map_fnode(dev, ino, &bh);
1575 if (!fnode)
1576 return 0;
1577
1578 dno = fnode->u.external[0].disk_secno;
1579 brelse(bh);
1580 return dno;
1581 }
1582
1583 /* Map an fnode into a buffer and return pointers to it and to the buffer. */
1584
1585 static struct fnode *map_fnode(dev_t dev, ino_t ino, struct buffer_head **bhp)
/* */
1586 {
1587 struct fnode *fnode;
1588
1589 if (ino == 0) {
1590 printk("HPFS: missing fnode\n");
1591 return 0;
1592 }
1593
1594 fnode = map_sector(dev, ino_secno(ino), bhp);
1595 if (fnode)
1596 if (fnode->magic != FNODE_MAGIC) {
1597 printk("HPFS: map_fnode: bad fnode pointer\n");
1598 brelse(*bhp);
1599 return 0;
1600 }
1601 return fnode;
1602 }
1603
1604 /* Map an anode into a buffer and return pointers to it and to the buffer. */
1605
1606 static struct anode *map_anode(dev_t dev, unsigned secno,
/* */
1607 struct buffer_head **bhp)
1608 {
1609 struct anode *anode;
1610
1611 if (secno == 0) {
1612 printk("HPFS: missing anode\n");
1613 return 0;
1614 }
1615
1616 anode = map_sector(dev, secno, bhp);
1617 if (anode)
1618 if (anode->magic != ANODE_MAGIC || anode->self != secno) {
1619 printk("HPFS: map_anode: bad anode pointer\n");
1620 brelse(*bhp);
1621 return 0;
1622 }
1623 return anode;
1624 }
1625
1626 /* Map a dnode into a buffer and return pointers to it and to the buffer. */
1627
1628 static struct dnode *map_dnode(dev_t dev, unsigned secno,
/* */
1629 struct quad_buffer_head *qbh)
1630 {
1631 struct dnode *dnode;
1632
1633 if (secno == 0) {
1634 printk("HPFS: missing dnode\n");
1635 return 0;
1636 }
1637
1638 dnode = map_4sectors(dev, secno, qbh);
1639 if (dnode)
1640 if (dnode->magic != DNODE_MAGIC || dnode->self != secno) {
1641 printk("HPFS: map_dnode: bad dnode pointer\n");
1642 brelse4(qbh);
1643 return 0;
1644 }
1645 return dnode;
1646 }
1647
1648 /* Map a sector into a buffer and return pointers to it and to the buffer. */
1649
1650 static void *map_sector(dev_t dev, unsigned secno, struct buffer_head **bhp)
/* */
1651 {
1652 struct buffer_head *bh;
1653
1654 if ((*bhp = bh = bread(dev, secno, 512)) != 0)
1655 return bh->b_data;
1656 else {
1657 printk("HPFS: map_sector: read error\n");
1658 return 0;
1659 }
1660 }
1661
1662 /* Map 4 sectors into a 4buffer and return pointers to it and to the buffer. */
1663
1664 static void *map_4sectors(dev_t dev, unsigned secno,
/* */
1665 struct quad_buffer_head *qbh)
1666 {
1667 struct buffer_head *bh;
1668 char *data;
1669
1670 if (secno & 3) {
1671 printk("HPFS: map_4sectors: unaligned read\n");
1672 return 0;
1673 }
1674
1675 qbh->data = data = kmalloc(2048, GFP_KERNEL);
1676 if (!data)
1677 goto bail;
1678
1679 qbh->bh[0] = bh = breada(dev,
1680 secno, secno + 1, secno + 2, secno + 3, -1);
1681 if (!bh)
1682 goto bail0;
1683 memcpy(data, bh->b_data, 512);
1684
1685 qbh->bh[1] = bh = bread(dev, secno + 1, 512);
1686 if (!bh)
1687 goto bail1;
1688 memcpy(data + 512, bh->b_data, 512);
1689
1690 qbh->bh[2] = bh = bread(dev, secno + 2, 512);
1691 if (!bh)
1692 goto bail2;
1693 memcpy(data + 2 * 512, bh->b_data, 512);
1694
1695 qbh->bh[3] = bh = bread(dev, secno + 3, 512);
1696 if (!bh)
1697 goto bail3;
1698 memcpy(data + 3 * 512, bh->b_data, 512);
1699
1700 return data;
1701
1702 bail3:
1703 brelse(qbh->bh[2]);
1704 bail2:
1705 brelse(qbh->bh[1]);
1706 bail1:
1707 brelse(qbh->bh[0]);
1708 bail0:
1709 kfree_s(data, 2048);
1710 bail:
1711 printk("HPFS: map_4sectors: read error\n");
1712 return 0;
1713 }
1714
1715 /* Deallocate a 4-buffer block */
1716
1717 static void brelse4(struct quad_buffer_head *qbh)
/* ![[last]](../icons/n_last.png)
*/
1718 {
1719 brelse(qbh->bh[3]);
1720 brelse(qbh->bh[2]);
1721 brelse(qbh->bh[1]);
1722 brelse(qbh->bh[0]);
1723 kfree_s(qbh->data, 2048);
1724 }
![[bottom]](../icons/n_bottom.png){kind=icon}
*/