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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_, MSJ 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/kernel.h>
20 #include <linux/sched.h>
21 #include <linux/locks.h>
22 #include <linux/stat.h>
23 #include <linux/string.h>
24 #include <asm/bitops.h>
25 #include <asm/segment.h>
26
27 #include "hpfs.h"
28 #include "hpfs_caps.h"
29
30 /*
31 * HPFS is a mixture of 512-byte blocks and 2048-byte blocks. The 2k blocks
32 * are used for directories and bitmaps. For bmap to work, we must run the
33 * file system with 512-byte blocks. The 2k blocks are assembled in buffers
34 * obtained from kmalloc.
35 *
36 * For a file's i-number we use the sector number of its fnode, coded.
37 * (Directory ino's are even, file ino's are odd, and ino >> 1 is the
38 * sector address of the fnode. This is a hack to allow lookup() to
39 * tell read_inode() whether it is necessary to read the fnode.)
40 *
41 * The map_xxx routines all read something into a buffer and return a
42 * pointer somewhere in the buffer. The caller must do the brelse.
43 * The other routines are balanced.
44 *
45 * For details on the data structures see hpfs.h and the Duncan paper.
46 *
47 * Overview
48 *
49 * [ The names of these data structures, except fnode, are not Microsoft's
50 * or IBM's. I don't know what names they use. The semantics described
51 * here are those of this implementation, and any coincidence between it
52 * and real HPFS is to be hoped for but not guaranteed by me, and
53 * certainly not guaranteed by MS or IBM. Who know nothing about this. ]
54 *
55 * [ Also, the following will make little sense if you haven't read the
56 * Duncan paper, which is excellent. ]
57 *
58 * HPFS is a tree. There are 3 kinds of nodes. A directory is a tree
59 * of dnodes, and a file's allocation info is a tree of sector runs
60 * stored in fnodes and anodes.
61 *
62 * The top pointer is in the super block, it points to the fnode of the
63 * root directory.
64 *
65 * The root directory -- all directories -- gives file names, dates &c,
66 * and fnode addresses. If the directory fits in one dnode, that's it,
67 * otherwise the top dnode points to other dnodes, forming a tree. A
68 * dnode tree (one directory) might look like
69 *
70 * ((a b c) d (e f g) h (i j) k l (m n o p))
71 *
72 * The subtrees appear between the files. Each dir entry contains, along
73 * with the name and fnode, a dnode pointer to the subtree that precedes it
74 * (if there is one; a flag tells that). The first entry in every directory
75 * is ^A^A, the "." entry for the directory itself. The last entry in every
76 * dnode is \377, a fake entry whose only valid fields are the bit marking
77 * it last and the down pointer to the subtree preceding it, if any.
78 *
79 * The "value" field of directory entries is an fnode address. The fnode
80 * tells where the sectors of the file are. The fnode for a subdirectory
81 * contains one pointer, to the root dnode of the subdirectory. The fnode
82 * for a data file contains, in effect, a tiny anode. (Most of the space
83 * in fnodes is for extended attributes.)
84 *
85 * anodes and the anode part of fnodes are trees of extents. An extent
86 * is a (length, disk address) pair, labeled with the file address being
87 * mapped. E.g.,
88 *
89 * (0: 3@1000 3: 1@2000 4: 2@10)
90 *
91 * means the file:disk sector map (0:1000 1:1001 2:1002 3:2000 4:10 5:11).
92 *
93 * There is space for 8 file:len@disk triples in an fnode, or for 40 in an
94 * anode. If this is insufficient, subtrees are used, as in
95 *
96 * (6: (0: 3@1000 3: 1@2000 4: 2@10) 12: (6: 3@8000 9: 1@9000 10: 2@20))
97 *
98 * The label on a subtree is the first address *after* that tree. The
99 * subtrees are always anodes. The label:subtree pairs require only
100 * two words each, so non-leaf subtrees have a different format; there
101 * is room for 12 label:subtree pairs in an fnode, or 60 in an anode.
102 *
103 * Within a directory, each dnode contains a pointer up to its parent
104 * dnode. The root dnode points up to the directory's fnode.
105 *
106 * Each fnode contains a pointer to the directory that contains it
107 * (to the fnode of the directory). So this pointer in a directory
108 * fnode is "..".
109 *
110 * On the disk, dnodes are all together in the center of the partition,
111 * and HPFS even manages to put all the dnodes for a single directory
112 * together, generally. fnodes are out with the data. anodes are seldom
113 * seen -- in fact noncontiguous files are seldom seen. I think this is
114 * partly the open() call that lets programs specify the length of an
115 * output file when they know it, and partly because HPFS.IFS really is
116 * very good at resisting fragmentation.
117 */
118
119 /* notation */
120
121 #define little_ushort(x) (*(unsigned short *) &(x))
122 typedef void nonconst;
123
124 /* super block ops */
125
126 static void hpfs_read_inode(struct inode *);
127 static void hpfs_put_super(struct super_block *);
128 static void hpfs_statfs(struct super_block *, struct statfs *, int);
129 static int hpfs_remount_fs(struct super_block *, int *, char *);
130
131 static const struct super_operations hpfs_sops =
132 {
133 hpfs_read_inode, /* read_inode */
134 NULL, /* notify_change */
135 NULL, /* write_inode */
136 NULL, /* put_inode */
137 hpfs_put_super, /* put_super */
138 NULL, /* write_super */
139 hpfs_statfs, /* statfs */
140 hpfs_remount_fs, /* remount_fs */
141 };
142
143 /* file ops */
144
145 static int hpfs_file_read(struct inode *, struct file *, char *, int);
146 static secno hpfs_bmap(struct inode *, unsigned);
147
148 static const struct file_operations hpfs_file_ops =
149 {
150 NULL, /* lseek - default */
151 hpfs_file_read, /* read */
152 NULL, /* write */
153 NULL, /* readdir - bad */
154 NULL, /* select - default */
155 NULL, /* ioctl - default */
156 generic_mmap, /* mmap */
157 NULL, /* no special open is needed */
158 NULL, /* release */
159 file_fsync, /* fsync */
160 };
161
162 static const struct inode_operations hpfs_file_iops =
163 {
164 (nonconst *) & hpfs_file_ops, /* default file operations */
165 NULL, /* create */
166 NULL, /* lookup */
167 NULL, /* link */
168 NULL, /* unlink */
169 NULL, /* symlink */
170 NULL, /* mkdir */
171 NULL, /* rmdir */
172 NULL, /* mknod */
173 NULL, /* rename */
174 NULL, /* readlink */
175 NULL, /* follow_link */
176 (int (*)(struct inode *, int))
177 &hpfs_bmap, /* bmap */
178 NULL, /* truncate */
179 NULL, /* permission */
180 };
181
182 /* directory ops */
183
184 static int hpfs_dir_read(struct inode *inode, struct file *filp,
185 char *buf, int count);
186 static int hpfs_readdir(struct inode *inode, struct file *filp,
187 void *dirent, filldir_t filldir);
188 static int hpfs_lookup(struct inode *, const char *, int, struct inode **);
189
190 static const struct file_operations hpfs_dir_ops =
191 {
192 NULL, /* lseek - default */
193 hpfs_dir_read, /* read */
194 NULL, /* write - bad */
195 hpfs_readdir, /* readdir */
196 NULL, /* select - default */
197 NULL, /* ioctl - default */
198 NULL, /* mmap */
199 NULL, /* no special open code */
200 NULL, /* no special release code */
201 file_fsync, /* fsync */
202 };
203
204 static const struct inode_operations hpfs_dir_iops =
205 {
206 (nonconst *) & hpfs_dir_ops, /* default directory file ops */
207 NULL, /* create */
208 hpfs_lookup, /* lookup */
209 NULL, /* link */
210 NULL, /* unlink */
211 NULL, /* symlink */
212 NULL, /* mkdir */
213 NULL, /* rmdir */
214 NULL, /* mknod */
215 NULL, /* rename */
216 NULL, /* readlink */
217 NULL, /* follow_link */
218 NULL, /* bmap */
219 NULL, /* truncate */
220 NULL, /* permission */
221 };
222
223 /* Four 512-byte buffers and the 2k block obtained by concatenating them */
224
225 struct quad_buffer_head {
226 struct buffer_head *bh[4];
227 void *data;
228 };
229
230 /* forwards */
231
232 static int parse_opts(char *opts, uid_t *uid, gid_t *gid, umode_t *umask,
233 int *lowercase, int *conv);
234 static int check_warn(int not_ok,
235 const char *p1, const char *p2, const char *p3);
236 static int zerop(void *addr, unsigned len);
237 static void count_dnodes(struct inode *inode, dnode_secno dno,
238 unsigned *n_dnodes, unsigned *n_subdirs);
239 static unsigned count_bitmap(struct super_block *s);
240 static unsigned count_one_bitmap(dev_t dev, secno secno);
241 static secno bplus_lookup(struct inode *inode, struct bplus_header *b,
242 secno file_secno, struct buffer_head **bhp);
243 static struct hpfs_dirent *map_dirent(struct inode *inode, dnode_secno dno,
244 const unsigned char *name, unsigned len,
245 struct quad_buffer_head *qbh);
246 static struct hpfs_dirent *map_pos_dirent(struct inode *inode, loff_t *posp,
247 struct quad_buffer_head *qbh);
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->fs->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 analogous.
723 */
724
725 static void hpfs_statfs(struct super_block *s, struct statfs *buf, int bufsiz)
/* */
726 {
727 struct statfs tmp;
728
729 /*
730 * count the bits in the bitmaps, unless we already have
731 */
732 if (s->s_hpfs_n_free == -1) {
733 s->s_hpfs_n_free = count_bitmap(s);
734 s->s_hpfs_n_free_dnodes =
735 count_one_bitmap(s->s_dev, s->s_hpfs_dmap);
736 }
737
738 /*
739 * fill in the user statfs struct
740 */
741 tmp.f_type = s->s_magic;
742 tmp.f_bsize = 512;
743 tmp.f_blocks = s->s_hpfs_fs_size;
744 tmp.f_bfree = s->s_hpfs_n_free;
745 tmp.f_bavail = s->s_hpfs_n_free;
746 tmp.f_files = s->s_hpfs_dirband_size;
747 tmp.f_ffree = s->s_hpfs_n_free_dnodes;
748 tmp.f_namelen = 254;
749 memcpy_tofs(buf, &tmp, bufsiz);
750 }
751
752 /*
753 * remount. Don't let read only be turned off.
754 */
755
756 static int hpfs_remount_fs(struct super_block *s, int *flags, char *data)
/* */
757 {
758 if (!(*flags & MS_RDONLY))
759 return -EINVAL;
760 return 0;
761 }
762
763 /*
764 * count the dnodes in a directory, and the subdirs.
765 */
766
767 static void count_dnodes(struct inode *inode, dnode_secno dno,
/* */
768 unsigned *n_dnodes, unsigned *n_subdirs)
769 {
770 struct quad_buffer_head qbh;
771 struct dnode *dnode;
772 struct hpfs_dirent *de;
773 struct hpfs_dirent *de_end;
774
775 dnode = map_dnode(inode->i_dev, dno, &qbh);
776 if (!dnode)
777 return;
778 de = dnode_first_de(dnode);
779 de_end = dnode_end_de(dnode);
780
781 (*n_dnodes)++;
782
783 for (; de < de_end; de = de_next_de(de)) {
784 if (de->down)
785 count_dnodes(inode, de_down_pointer(de),
786 n_dnodes, n_subdirs);
787 if (de->directory && !de->first)
788 (*n_subdirs)++;
789 if (de->last || de->length == 0)
790 break;
791 }
792
793 brelse4(&qbh);
794 }
795
796 /*
797 * count the bits in the free space bit maps
798 */
799
800 static unsigned count_bitmap(struct super_block *s)
/* */
801 {
802 unsigned n, count, n_bands;
803 secno *bitmaps;
804 struct quad_buffer_head qbh;
805
806 /*
807 * there is one bit map for each 16384 sectors
808 */
809 n_bands = (s->s_hpfs_fs_size + 0x3fff) >> 14;
810
811 /*
812 * their locations are given in an array pointed to by the super
813 * block
814 */
815 bitmaps = map_4sectors(s->s_dev, s->s_hpfs_bitmaps, &qbh);
816 if (!bitmaps)
817 return 0;
818
819 count = 0;
820
821 /*
822 * map each one and count the free sectors
823 */
824 for (n = 0; n < n_bands; n++)
825 if (bitmaps[n] == 0)
826 printk("HPFS: bit map pointer missing\n");
827 else
828 count += count_one_bitmap(s->s_dev, bitmaps[n]);
829
830 brelse4(&qbh);
831 return count;
832 }
833
834 /*
835 * Read in one bit map, count the bits, return the count.
836 */
837
838 static unsigned count_one_bitmap(dev_t dev, secno secno)
/* */
839 {
840 struct quad_buffer_head qbh;
841 char *bits;
842 unsigned i, count;
843
844 bits = map_4sectors(dev, secno, &qbh);
845 if (!bits)
846 return 0;
847
848 count = 0;
849
850 for (i = 0; i < 8 * 2048; i++)
851 count += (test_bit(i, bits) != 0);
852 brelse4(&qbh);
853
854 return count;
855 }
856
857 /* file ops */
858
859 /*
860 * read. Read the bytes, put them in buf, return the count.
861 */
862
863 static int hpfs_file_read(struct inode *inode, struct file *filp,
/* */
864 char *buf, int count)
865 {
866 unsigned q, r, n, n0;
867 struct buffer_head *bh;
868 char *block;
869 char *start;
870
871 if (inode == 0 || !S_ISREG(inode->i_mode))
872 return -EINVAL;
873
874 /*
875 * truncate count at EOF
876 */
877 if (count > inode->i_size - (off_t) filp->f_pos)
878 count = inode->i_size - filp->f_pos;
879
880 start = buf;
881 while (count > 0) {
882 /*
883 * get file sector number, offset in sector, length to end of
884 * sector
885 */
886 q = filp->f_pos >> 9;
887 r = filp->f_pos & 511;
888 n = 512 - r;
889
890 /*
891 * get length to copy to user buffer
892 */
893 if (n > count)
894 n = count;
895
896 /*
897 * read the sector, copy to user
898 */
899 block = map_sector(inode->i_dev, hpfs_bmap(inode, q), &bh);
900 if (!block)
901 return -EIO;
902
903 /*
904 * but first decide if it has \r\n, if the mount option said
905 * to do that
906 */
907 if (inode->i_hpfs_conv == CONV_AUTO)
908 inode->i_hpfs_conv = choose_conv(block + r, n);
909
910 if (inode->i_hpfs_conv == CONV_BINARY) {
911 /*
912 * regular copy, output length is same as input
913 * length
914 */
915 memcpy_tofs(buf, block + r, n);
916 n0 = n;
917 }
918 else {
919 /*
920 * squeeze out \r, output length varies
921 */
922 n0 = convcpy_tofs(buf, block + r, n);
923 if (count > inode->i_size - (off_t) filp->f_pos - n + n0)
924 count = inode->i_size - filp->f_pos - n + n0;
925 }
926
927 brelse(bh);
928
929 /*
930 * advance input n bytes, output n0 bytes
931 */
932 filp->f_pos += n;
933 buf += n0;
934 count -= n0;
935 }
936
937 return buf - start;
938 }
939
940 /*
941 * This routine implements conv=auto. Return CONV_BINARY or CONV_TEXT.
942 */
943
944 static unsigned choose_conv(unsigned char *p, unsigned len)
/* */
945 {
946 unsigned tvote, bvote;
947 unsigned c;
948
949 tvote = bvote = 0;
950
951 while (len--) {
952 c = *p++;
953 if (c < ' ')
954 if (c == '\r' && len && *p == '\n')
955 tvote += 10;
956 else if (c == '\t' || c == '\n');
957 else
958 bvote += 5;
959 else if (c < '\177')
960 tvote++;
961 else
962 bvote += 5;
963 }
964
965 if (tvote > bvote)
966 return CONV_TEXT;
967 else
968 return CONV_BINARY;
969 }
970
971 /*
972 * This routine implements conv=text. :s/crlf/nl/
973 */
974
975 static unsigned convcpy_tofs(unsigned char *out, unsigned char *in,
/* */
976 unsigned len)
977 {
978 unsigned char *start = out;
979
980 while (len--) {
981 unsigned c = *in++;
982 if (c == '\r' && (len == 0 || *in == '\n'));
983 else
984 put_user(c, out++);
985 }
986
987 return out - start;
988 }
989
990 /*
991 * Return the disk sector number containing a file sector.
992 */
993
994 static secno hpfs_bmap(struct inode *inode, unsigned file_secno)
/* */
995 {
996 unsigned n, disk_secno;
997 struct fnode *fnode;
998 struct buffer_head *bh;
999
1000 /*
1001 * There is one sector run cached in the inode. See if the sector is
1002 * in it.
1003 */
1004
1005 n = file_secno - inode->i_hpfs_file_sec;
1006 if (n < inode->i_hpfs_n_secs)
1007 return inode->i_hpfs_disk_sec + n;
1008
1009 /*
1010 * No, read the fnode and go find the sector.
1011 */
1012
1013 else {
1014 fnode = map_fnode(inode->i_dev, inode->i_ino, &bh);
1015 if (!fnode)
1016 return 0;
1017 disk_secno = bplus_lookup(inode, &fnode->btree,
1018 file_secno, &bh);
1019 brelse(bh);
1020 return disk_secno;
1021 }
1022 }
1023
1024 /*
1025 * Search allocation tree *b for the given file sector number and return
1026 * the disk sector number. Buffer *bhp has the tree in it, and can be
1027 * reused for subtrees when access to *b is no longer needed.
1028 * *bhp is busy on entry and exit.
1029 */
1030
1031 static secno bplus_lookup(struct inode *inode, struct bplus_header *b,
/* */
1032 secno file_secno, struct buffer_head **bhp)
1033 {
1034 int i;
1035
1036 /*
1037 * A leaf-level tree gives a list of sector runs. Find the one
1038 * containing the file sector we want, cache the map info in the
1039 * inode for later, and return the corresponding disk sector.
1040 */
1041
1042 if (!b->internal) {
1043 struct bplus_leaf_node *n = b->u.external;
1044 for (i = 0; i < b->n_used_nodes; i++) {
1045 unsigned t = file_secno - n[i].file_secno;
1046 if (t < n[i].length) {
1047 inode->i_hpfs_file_sec = n[i].file_secno;
1048 inode->i_hpfs_disk_sec = n[i].disk_secno;
1049 inode->i_hpfs_n_secs = n[i].length;
1050 return n[i].disk_secno + t;
1051 }
1052 }
1053 }
1054
1055 /*
1056 * A non-leaf tree gives a list of subtrees. Find the one containing
1057 * the file sector we want, read it in, and recurse to search it.
1058 */
1059
1060 else {
1061 struct bplus_internal_node *n = b->u.internal;
1062 for (i = 0; i < b->n_used_nodes; i++) {
1063 if (file_secno < n[i].file_secno) {
1064 struct anode *anode;
1065 anode_secno ano = n[i].down;
1066 brelse(*bhp);
1067 anode = map_anode(inode->i_dev, ano, bhp);
1068 if (!anode)
1069 break;
1070 return bplus_lookup(inode, &anode->btree,
1071 file_secno, bhp);
1072 }
1073 }
1074 }
1075
1076 /*
1077 * If we get here there was a hole in the file. As far as I know we
1078 * never do get here, but falling off the end would be indelicate. So
1079 * return a pointer to a handy all-zero sector. This is not a
1080 * reasonable way to handle files with holes if they really do
1081 * happen.
1082 */
1083
1084 printk("HPFS: bplus_lookup: sector not found\n");
1085 return 15;
1086 }
1087
1088 /* directory ops */
1089
1090 /*
1091 * lookup. Search the specified directory for the specified name, set
1092 * *result to the corresponding inode.
1093 *
1094 * lookup uses the inode number to tell read_inode whether it is reading
1095 * the inode of a directory or a file -- file ino's are odd, directory
1096 * ino's are even. read_inode avoids i/o for file inodes; everything
1097 * needed is up here in the directory. (And file fnodes are out in
1098 * the boondocks.)
1099 */
1100
1101 static int hpfs_lookup(struct inode *dir, const char *name, int len,
/* */
1102 struct inode **result)
1103 {
1104 struct quad_buffer_head qbh;
1105 struct hpfs_dirent *de;
1106 struct inode *inode;
1107 ino_t ino;
1108
1109 /* In case of madness */
1110
1111 *result = 0;
1112 if (dir == 0)
1113 return -ENOENT;
1114 if (!S_ISDIR(dir->i_mode))
1115 goto bail;
1116
1117 /*
1118 * Read in the directory entry. "." is there under the name ^A^A .
1119 * Always read the dir even for . and .. in case we need the dates.
1120 */
1121
1122 if (name[0] == '.' && len == 1)
1123 de = map_dirent(dir, dir->i_hpfs_dno, "\001\001", 2, &qbh);
1124 else if (name[0] == '.' && name[1] == '.' && len == 2)
1125 de = map_dirent(dir,
1126 fnode_dno(dir->i_dev, dir->i_hpfs_parent_dir),
1127 "\001\001", 2, &qbh);
1128 else
1129 de = map_dirent(dir, dir->i_hpfs_dno, name, len, &qbh);
1130
1131 /*
1132 * This is not really a bailout, just means file not found.
1133 */
1134
1135 if (!de)
1136 goto bail;
1137
1138 /*
1139 * Get inode number, what we're after.
1140 */
1141
1142 if (de->directory)
1143 ino = dir_ino(de->fnode);
1144 else
1145 ino = file_ino(de->fnode);
1146
1147 /*
1148 * Go find or make an inode.
1149 */
1150
1151 if (!(inode = iget(dir->i_sb, ino)))
1152 goto bail1;
1153
1154 /*
1155 * Fill in the info from the directory if this is a newly created
1156 * inode.
1157 */
1158
1159 if (!inode->i_atime) {
1160 inode->i_atime = local_to_gmt(de->read_date);
1161 inode->i_mtime = local_to_gmt(de->write_date);
1162 inode->i_ctime = local_to_gmt(de->creation_date);
1163 if (de->read_only)
1164 inode->i_mode &= ~0222;
1165 if (!de->directory) {
1166 inode->i_size = de->file_size;
1167 /*
1168 * i_blocks should count the fnode and any anodes.
1169 * We count 1 for the fnode and don't bother about
1170 * anodes -- the disk heads are on the directory band
1171 * and we want them to stay there.
1172 */
1173 inode->i_blocks = 1 + ((inode->i_size + 511) >> 9);
1174 }
1175 }
1176
1177 brelse4(&qbh);
1178
1179 /*
1180 * Made it.
1181 */
1182
1183 *result = inode;
1184 iput(dir);
1185 return 0;
1186
1187 /*
1188 * Didn't.
1189 */
1190 bail1:
1191 brelse4(&qbh);
1192 bail:
1193 iput(dir);
1194 return -ENOENT;
1195 }
1196
1197 /*
1198 * Compare two counted strings ignoring case.
1199 * HPFS directory order sorts letters as if they're upper case.
1200 */
1201
1202 static inline int memcasecmp(const unsigned char *s1, const unsigned char *s2,
/* */
1203 unsigned n)
1204 {
1205 int t;
1206
1207 if (n != 0)
1208 do {
1209 unsigned c1 = linux_char_to_upper_linux (*s1++);
1210 unsigned c2 = hpfs_char_to_upper_linux (*s2++);
1211 if ((t = c1 - c2) != 0)
1212 return t;
1213 } while (--n != 0);
1214
1215 return 0;
1216 }
1217
1218 /*
1219 * Search a directory for the given name, return a pointer to its dir entry
1220 * and a pointer to the buffer containing it.
1221 */
1222
1223 static struct hpfs_dirent *map_dirent(struct inode *inode, dnode_secno dno,
/* */
1224 const unsigned char *name, unsigned len,
1225 struct quad_buffer_head *qbh)
1226 {
1227 struct dnode *dnode;
1228 struct hpfs_dirent *de;
1229 struct hpfs_dirent *de_end;
1230 int t, l;
1231
1232 /*
1233 * read the dnode at the root of our subtree
1234 */
1235 dnode = map_dnode(inode->i_dev, dno, qbh);
1236 if (!dnode)
1237 return 0;
1238
1239 /*
1240 * get pointers to start and end+1 of dir entries
1241 */
1242 de = dnode_first_de(dnode);
1243 de_end = dnode_end_de(dnode);
1244
1245 /*
1246 * look through the entries for the name we're after
1247 */
1248 for ( ; de < de_end; de = de_next_de(de)) {
1249
1250 /*
1251 * compare names
1252 */
1253 l = len < de->namelen ? len : de->namelen;
1254 t = memcasecmp(name, de->name, l);
1255
1256 /*
1257 * initial substring matches, compare lengths
1258 */
1259 if (t == 0) {
1260 t = len - de->namelen;
1261 /* bingo */
1262 if (t == 0)
1263 return de;
1264 }
1265
1266 /*
1267 * wanted name .lt. dir name => not present.
1268 */
1269 if (t < 0) {
1270 /*
1271 * if there is a subtree, search it.
1272 */
1273 if (de->down) {
1274 dnode_secno sub_dno = de_down_pointer(de);
1275 brelse4(qbh);
1276 return map_dirent(inode, sub_dno,
1277 name, len, qbh);
1278 }
1279 else
1280 break;
1281 }
1282
1283 /*
1284 * de->last is set on the last name in the dnode (it's always
1285 * a "\377" pseudo entry). de->length == 0 means we're about
1286 * to infinite loop. This test does nothing in a well-formed
1287 * dnode.
1288 */
1289 if (de->last || de->length == 0)
1290 break;
1291 }
1292
1293 /*
1294 * name not found.
1295 */
1296 brelse4(qbh);
1297 return 0;
1298 }
1299
1300 /*
1301 * readdir. Return exactly 1 dirent. (I tried and tried, but currently
1302 * the interface with libc just does not permit more than 1. If it gets
1303 * fixed, throw this out and just walk the tree and write records into
1304 * the user buffer.)
1305 *
1306 * [ we now can handle multiple dirents, although the current libc doesn't
1307 * use that. The way hpfs does this is pretty strange, as we need to do
1308 * the name translation etc before calling "filldir()". This is untested,
1309 * as I don't have any hpfs partitions to test against. Linus ]
1310 *
1311 * We keep track of our position in the dnode tree with a sort of
1312 * dewey-decimal record of subtree locations. Like so:
1313 *
1314 * (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)
1315 *
1316 * Subtrees appear after their file, out of lexical order,
1317 * which would be before their file. It's easier.
1318 *
1319 * A directory can't hold more than 56 files, so 6 bits are used for
1320 * position numbers. If the tree is so deep that the position encoding
1321 * doesn't fit, I'm sure something absolutely fascinating happens.
1322 *
1323 * The actual sequence of f_pos values is
1324 * 0 => . -1 => .. 1 1.1 ... 8.9 9 => files -2 => eof
1325 *
1326 * The directory inode caches one position-to-dnode correspondence so
1327 * we won't have to repeatedly scan the top levels of the tree.
1328 */
1329
1330 /*
1331 * Translate the given name: Blam it to lowercase if the mount option said to.
1332 */
1333
1334 static void translate_hpfs_name(const unsigned char * from, int len, char * to, int lowercase)
/* */
1335 {
1336 while (len > 0) {
1337 unsigned t = *from;
1338 len--;
1339 if (lowercase)
1340 t = hpfs_char_to_lower_linux (t);
1341 else
1342 t = hpfs_char_to_linux (t);
1343 *to = t;
1344 from++;
1345 to++;
1346 }
1347 }
1348
1349 static int hpfs_readdir(struct inode *inode, struct file *filp, void * dirent,
/* */
1350 filldir_t filldir)
1351 {
1352 struct quad_buffer_head qbh;
1353 struct hpfs_dirent *de;
1354 int namelen, lc;
1355 ino_t ino;
1356 char * tempname;
1357 long old_pos;
1358
1359 if (inode == 0
1360 || inode->i_sb == 0
1361 || !S_ISDIR(inode->i_mode))
1362 return -EBADF;
1363
1364 tempname = (char *) __get_free_page(GFP_KERNEL);
1365 if (!tempname)
1366 return -ENOMEM;
1367
1368 lc = inode->i_sb->s_hpfs_lowercase;
1369 switch ((long) filp->f_pos) {
1370 case -2:
1371 break;
1372
1373 case 0:
1374 if (filldir(dirent, ".", 1, filp->f_pos, inode->i_ino) < 0)
1375 break;
1376 filp->f_pos = -1;
1377 /* fall through */
1378
1379 case -1:
1380 if (filldir(dirent, "..", 2, filp->f_pos, inode->i_hpfs_parent_dir) < 0)
1381 break;
1382 filp->f_pos = 1;
1383 /* fall through */
1384
1385 default:
1386 for (;;) {
1387 old_pos = filp->f_pos;
1388 de = map_pos_dirent(inode, &filp->f_pos, &qbh);
1389 if (!de) {
1390 filp->f_pos = -2;
1391 break;
1392 }
1393 namelen = de->namelen;
1394 translate_hpfs_name(de->name, namelen, tempname, lc);
1395 if (de->directory)
1396 ino = dir_ino(de->fnode);
1397 else
1398 ino = file_ino(de->fnode);
1399 brelse4(&qbh);
1400 if (filldir(dirent, tempname, namelen, old_pos, ino) < 0) {
1401 filp->f_pos = old_pos;
1402 break;
1403 }
1404 }
1405 }
1406 free_page((unsigned long) tempname);
1407 return 0;
1408 }
1409
1410 /*
1411 * Map the dir entry at subtree coordinates given by *posp, and
1412 * increment *posp to point to the following dir entry.
1413 */
1414
1415 static struct hpfs_dirent *map_pos_dirent(struct inode *inode, loff_t *posp,
/* */
1416 struct quad_buffer_head *qbh)
1417 {
1418 unsigned pos, q, r;
1419 dnode_secno dno;
1420 struct hpfs_dirent *de;
1421
1422 /*
1423 * Get the position code and split off the rightmost index r
1424 */
1425
1426 pos = *posp;
1427 q = pos >> 6;
1428 r = pos & 077;
1429
1430 /*
1431 * Get the sector address of the dnode
1432 * pointed to by the leading part q
1433 */
1434
1435 dno = dir_subdno(inode, q);
1436 if (!dno)
1437 return 0;
1438
1439 /*
1440 * Get the entry at index r in dnode q
1441 */
1442
1443 de = map_nth_dirent(inode->i_dev, dno, r, qbh);
1444
1445 /*
1446 * If none, we're out of files in this dnode. Ascend.
1447 */
1448
1449 if (!de) {
1450 if (q == 0)
1451 return 0;
1452 *posp = q + 1;
1453 return map_pos_dirent(inode, posp, qbh);
1454 }
1455
1456 /*
1457 * If a subtree is here, descend.
1458 */
1459
1460 if (de->down)
1461 *posp = pos << 6 | 1;
1462 else
1463 *posp = pos + 1;
1464
1465 /*
1466 * Don't return the ^A^A and \377 entries.
1467 */
1468
1469 if (de->first || de->last) {
1470 brelse4(qbh);
1471 return map_pos_dirent(inode, posp, qbh);
1472 }
1473 else
1474 return de;
1475 }
1476
1477 /*
1478 * Return the address of the dnode with subtree coordinates given by pos.
1479 */
1480
1481 static dnode_secno dir_subdno(struct inode *inode, unsigned pos)
/* */
1482 {
1483 struct hpfs_dirent *de;
1484 struct quad_buffer_head qbh;
1485
1486 /*
1487 * 0 is the root dnode
1488 */
1489
1490 if (pos == 0)
1491 return inode->i_hpfs_dno;
1492
1493 /*
1494 * we have one pos->dnode translation cached in the inode
1495 */
1496
1497 else if (pos == inode->i_hpfs_dpos)
1498 return inode->i_hpfs_dsubdno;
1499
1500 /*
1501 * otherwise go look
1502 */
1503
1504 else {
1505 unsigned q = pos >> 6;
1506 unsigned r = pos & 077;
1507 dnode_secno dno;
1508
1509 /*
1510 * dnode at position q
1511 */
1512 dno = dir_subdno(inode, q);
1513 if (dno == 0)
1514 return 0;
1515
1516 /*
1517 * entry at index r
1518 */
1519 de = map_nth_dirent(inode->i_dev, dno, r, &qbh);
1520 if (!de || !de->down)
1521 return 0;
1522
1523 /*
1524 * get the dnode down pointer
1525 */
1526 dno = de_down_pointer(de);
1527 brelse4(&qbh);
1528
1529 /*
1530 * cache it for next time
1531 */
1532 inode->i_hpfs_dpos = pos;
1533 inode->i_hpfs_dsubdno = dno;
1534 return dno;
1535 }
1536 }
1537
1538 /*
1539 * Return the dir entry at index n in dnode dno, or 0 if there isn't one
1540 */
1541
1542 static struct hpfs_dirent *map_nth_dirent(dev_t dev, dnode_secno dno,
/* */
1543 int n,
1544 struct quad_buffer_head *qbh)
1545 {
1546 int i;
1547 struct hpfs_dirent *de, *de_end;
1548 struct dnode *dnode = map_dnode(dev, dno, qbh);
1549
1550 de = dnode_first_de(dnode);
1551 de_end = dnode_end_de(dnode);
1552
1553 for (i = 1; de < de_end; i++, de = de_next_de(de)) {
1554 if (i == n)
1555 return de;
1556 if (de->last || de->length == 0)
1557 break;
1558 }
1559
1560 brelse4(qbh);
1561 return 0;
1562 }
1563
1564 static int hpfs_dir_read(struct inode *inode, struct file *filp,
/* */
1565 char *buf, int count)
1566 {
1567 return -EISDIR;
1568 }
1569
1570 /* Return the dnode pointer in a directory fnode */
1571
1572 static dnode_secno fnode_dno(dev_t dev, ino_t ino)
/* */
1573 {
1574 struct buffer_head *bh;
1575 struct fnode *fnode;
1576 dnode_secno dno;
1577
1578 fnode = map_fnode(dev, ino, &bh);
1579 if (!fnode)
1580 return 0;
1581
1582 dno = fnode->u.external[0].disk_secno;
1583 brelse(bh);
1584 return dno;
1585 }
1586
1587 /* Map an fnode into a buffer and return pointers to it and to the buffer. */
1588
1589 static struct fnode *map_fnode(dev_t dev, ino_t ino, struct buffer_head **bhp)
/* */
1590 {
1591 struct fnode *fnode;
1592
1593 if (ino == 0) {
1594 printk("HPFS: missing fnode\n");
1595 return 0;
1596 }
1597
1598 fnode = map_sector(dev, ino_secno(ino), bhp);
1599 if (fnode)
1600 if (fnode->magic != FNODE_MAGIC) {
1601 printk("HPFS: map_fnode: bad fnode pointer\n");
1602 brelse(*bhp);
1603 return 0;
1604 }
1605 return fnode;
1606 }
1607
1608 /* Map an anode into a buffer and return pointers to it and to the buffer. */
1609
1610 static struct anode *map_anode(dev_t dev, unsigned secno,
/* */
1611 struct buffer_head **bhp)
1612 {
1613 struct anode *anode;
1614
1615 if (secno == 0) {
1616 printk("HPFS: missing anode\n");
1617 return 0;
1618 }
1619
1620 anode = map_sector(dev, secno, bhp);
1621 if (anode)
1622 if (anode->magic != ANODE_MAGIC || anode->self != secno) {
1623 printk("HPFS: map_anode: bad anode pointer\n");
1624 brelse(*bhp);
1625 return 0;
1626 }
1627 return anode;
1628 }
1629
1630 /* Map a dnode into a buffer and return pointers to it and to the buffer. */
1631
1632 static struct dnode *map_dnode(dev_t dev, unsigned secno,
/* */
1633 struct quad_buffer_head *qbh)
1634 {
1635 struct dnode *dnode;
1636
1637 if (secno == 0) {
1638 printk("HPFS: missing dnode\n");
1639 return 0;
1640 }
1641
1642 dnode = map_4sectors(dev, secno, qbh);
1643 if (dnode)
1644 if (dnode->magic != DNODE_MAGIC || dnode->self != secno) {
1645 printk("HPFS: map_dnode: bad dnode pointer\n");
1646 brelse4(qbh);
1647 return 0;
1648 }
1649 return dnode;
1650 }
1651
1652 /* Map a sector into a buffer and return pointers to it and to the buffer. */
1653
1654 static void *map_sector(dev_t dev, unsigned secno, struct buffer_head **bhp)
/* */
1655 {
1656 struct buffer_head *bh;
1657
1658 if ((*bhp = bh = bread(dev, secno, 512)) != 0)
1659 return bh->b_data;
1660 else {
1661 printk("HPFS: map_sector: read error\n");
1662 return 0;
1663 }
1664 }
1665
1666 /* Map 4 sectors into a 4buffer and return pointers to it and to the buffer. */
1667
1668 static void *map_4sectors(dev_t dev, unsigned secno,
/* */
1669 struct quad_buffer_head *qbh)
1670 {
1671 struct buffer_head *bh;
1672 char *data;
1673
1674 if (secno & 3) {
1675 printk("HPFS: map_4sectors: unaligned read\n");
1676 return 0;
1677 }
1678
1679 qbh->data = data = kmalloc(2048, GFP_KERNEL);
1680 if (!data)
1681 goto bail;
1682
1683 qbh->bh[0] = bh = breada(dev, secno, 512, 0, UINT_MAX);
1684 if (!bh)
1685 goto bail0;
1686 memcpy(data, bh->b_data, 512);
1687
1688 qbh->bh[1] = bh = bread(dev, secno + 1, 512);
1689 if (!bh)
1690 goto bail1;
1691 memcpy(data + 512, bh->b_data, 512);
1692
1693 qbh->bh[2] = bh = bread(dev, secno + 2, 512);
1694 if (!bh)
1695 goto bail2;
1696 memcpy(data + 2 * 512, bh->b_data, 512);
1697
1698 qbh->bh[3] = bh = bread(dev, secno + 3, 512);
1699 if (!bh)
1700 goto bail3;
1701 memcpy(data + 3 * 512, bh->b_data, 512);
1702
1703 return data;
1704
1705 bail3:
1706 brelse(qbh->bh[2]);
1707 bail2:
1708 brelse(qbh->bh[1]);
1709 bail1:
1710 brelse(qbh->bh[0]);
1711 bail0:
1712 kfree_s(data, 2048);
1713 bail:
1714 printk("HPFS: map_4sectors: read error\n");
1715 return 0;
1716 }
1717
1718 /* Deallocate a 4-buffer block */
1719
1720 static void brelse4(struct quad_buffer_head *qbh)
/* ![[last]](../icons/n_last.png)
*/
1721 {
1722 brelse(qbh->bh[3]);
1723 brelse(qbh->bh[2]);
1724 brelse(qbh->bh[1]);
1725 brelse(qbh->bh[0]);
1726 kfree_s(qbh->data, 2048);
1727 }
![[bottom]](../icons/n_bottom.png){kind=icon}
*/