File: /usr/src/linux/fs/fat/inode.c
1 /*
2 * linux/fs/fat/inode.c
3 *
4 * Written 1992,1993 by Werner Almesberger
5 * VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
6 * Rewritten for the constant inumbers support by Al Viro
7 *
8 * Fixes:
9 *
10 * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
11 */
12
13 #include <linux/config.h>
14 #include <linux/version.h>
15 #define __NO_VERSION__
16 #include <linux/module.h>
17
18 #include <linux/msdos_fs.h>
19 #include <linux/nls.h>
20 #include <linux/kernel.h>
21 #include <linux/sched.h>
22 #include <linux/errno.h>
23 #include <linux/string.h>
24 #include <linux/major.h>
25 #include <linux/blkdev.h>
26 #include <linux/fs.h>
27 #include <linux/stat.h>
28 #include <linux/locks.h>
29 #include <linux/fat_cvf.h>
30 #include <linux/slab.h>
31 #include <linux/bitops.h>
32 #include <linux/smp_lock.h>
33
34 #include "msbuffer.h"
35
36 #include <asm/uaccess.h>
37 #include <asm/unaligned.h>
38
39 extern struct cvf_format default_cvf;
40
41 /* #define FAT_PARANOIA 1 */
42 #define DEBUG_LEVEL 0
43 #ifdef FAT_DEBUG
44 # define PRINTK(x) printk x
45 #else
46 # define PRINTK(x)
47 #endif
48 #if (DEBUG_LEVEL >= 1)
49 # define PRINTK1(x) printk x
50 #else
51 # define PRINTK1(x)
52 #endif
53
54 /*
55 * New FAT inode stuff. We do the following:
56 * a) i_ino is constant and has nothing with on-disk location.
57 * b) FAT manages its own cache of directory entries.
58 * c) *This* cache is indexed by on-disk location.
59 * d) inode has an associated directory entry, all right, but
60 * it may be unhashed.
61 * e) currently entries are stored within struct inode. That should
62 * change.
63 * f) we deal with races in the following way:
64 * 1. readdir() and lookup() do FAT-dir-cache lookup.
65 * 2. rename() unhashes the F-d-c entry and rehashes it in
66 * a new place.
67 * 3. unlink() and rmdir() unhash F-d-c entry.
68 * 4. fat_write_inode() checks whether the thing is unhashed.
69 * If it is we silently return. If it isn't we do bread(),
70 * check if the location is still valid and retry if it
71 * isn't. Otherwise we do changes.
72 * 5. Spinlock is used to protect hash/unhash/location check/lookup
73 * 6. fat_clear_inode() unhashes the F-d-c entry.
74 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
75 * and consider negative result as cache miss.
76 */
77
78 #define FAT_HASH_BITS 8
79 #define FAT_HASH_SIZE (1UL << FAT_HASH_BITS)
80 #define FAT_HASH_MASK (FAT_HASH_SIZE-1)
81 static struct list_head fat_inode_hashtable[FAT_HASH_SIZE];
82 spinlock_t fat_inode_lock = SPIN_LOCK_UNLOCKED;
83
84 void fat_hash_init(void) {
85 int i;
86 for(i=0;i<FAT_HASH_SIZE;i++) {
87 INIT_LIST_HEAD(&fat_inode_hashtable[i]);
88 }
89 }
90
91 static inline unsigned long fat_hash(struct super_block *sb, int i_pos)
92 {
93 unsigned long tmp = (unsigned long)i_pos | (unsigned long) sb;
94 tmp = tmp + (tmp >> FAT_HASH_BITS) + (tmp >> FAT_HASH_BITS*2);
95 return tmp & FAT_HASH_MASK;
96 }
97
98 void fat_attach(struct inode *inode, int i_pos) {
99 spin_lock(&fat_inode_lock);
100 MSDOS_I(inode)->i_location = i_pos;
101 list_add(&MSDOS_I(inode)->i_fat_hash,
102 fat_inode_hashtable+fat_hash(inode->i_sb, i_pos));
103 spin_unlock(&fat_inode_lock);
104 }
105
106 void fat_detach(struct inode *inode) {
107 spin_lock(&fat_inode_lock);
108 MSDOS_I(inode)->i_location = 0;
109 list_del(&MSDOS_I(inode)->i_fat_hash);
110 INIT_LIST_HEAD(&MSDOS_I(inode)->i_fat_hash);
111 spin_unlock(&fat_inode_lock);
112 }
113
114 struct inode *fat_iget(struct super_block *sb, int i_pos) {
115 struct list_head *p = fat_inode_hashtable + fat_hash(sb, i_pos);
116 struct list_head *walk;
117 struct msdos_inode_info *i;
118 struct inode *inode = NULL;
119 spin_lock(&fat_inode_lock);
120 for(walk=p->next;walk!=p;walk=walk->next) {
121 i = list_entry(walk, struct msdos_inode_info, i_fat_hash);
122 if (i->i_fat_inode->i_sb != sb)
123 continue;
124 if (i->i_location != i_pos)
125 continue;
126 inode = igrab(i->i_fat_inode);
127 }
128 spin_unlock(&fat_inode_lock);
129 return inode;
130 }
131
132 static void fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de);
133
134 struct inode *fat_build_inode(struct super_block *sb,
135 struct msdos_dir_entry *de, int ino, int *res)
136 {
137 struct inode *inode;
138 *res = 0;
139 inode = fat_iget(sb, ino);
140 if (inode)
141 goto out;
142 inode = new_inode(sb);
143 *res = -ENOMEM;
144 if (!inode)
145 goto out;
146 *res = 0;
147 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
148 fat_fill_inode(inode, de);
149 fat_attach(inode, ino);
150 insert_inode_hash(inode);
151 out:
152 return inode;
153 }
154
155 void fat_delete_inode(struct inode *inode)
156 {
157 if (!is_bad_inode(inode)) {
158 lock_kernel();
159 inode->i_size = 0;
160 fat_truncate(inode);
161 unlock_kernel();
162 }
163 clear_inode(inode);
164 }
165
166 void fat_clear_inode(struct inode *inode)
167 {
168 if (is_bad_inode(inode))
169 return;
170 lock_kernel();
171 spin_lock(&fat_inode_lock);
172 fat_cache_inval_inode(inode);
173 list_del(&MSDOS_I(inode)->i_fat_hash);
174 spin_unlock(&fat_inode_lock);
175 unlock_kernel();
176 }
177
178 void fat_put_super(struct super_block *sb)
179 {
180 if (MSDOS_SB(sb)->cvf_format->cvf_version) {
181 dec_cvf_format_use_count_by_version(MSDOS_SB(sb)->cvf_format->cvf_version);
182 MSDOS_SB(sb)->cvf_format->unmount_cvf(sb);
183 }
184 if (MSDOS_SB(sb)->fat_bits == 32) {
185 fat_clusters_flush(sb);
186 }
187 fat_cache_inval_dev(sb->s_dev);
188 set_blocksize (sb->s_dev,BLOCK_SIZE);
189 if (MSDOS_SB(sb)->nls_disk) {
190 unload_nls(MSDOS_SB(sb)->nls_disk);
191 MSDOS_SB(sb)->nls_disk = NULL;
192 MSDOS_SB(sb)->options.codepage = 0;
193 }
194 if (MSDOS_SB(sb)->nls_io) {
195 unload_nls(MSDOS_SB(sb)->nls_io);
196 MSDOS_SB(sb)->nls_io = NULL;
197 }
198 /*
199 * Note: the iocharset option might have been specified
200 * without enabling nls_io, so check for it here.
201 */
202 if (MSDOS_SB(sb)->options.iocharset) {
203 kfree(MSDOS_SB(sb)->options.iocharset);
204 MSDOS_SB(sb)->options.iocharset = NULL;
205 }
206 }
207
208
209 static int parse_options(char *options,int *fat, int *debug,
210 struct fat_mount_options *opts,
211 char *cvf_format, char *cvf_options)
212 {
213 char *this_char,*value,save,*savep;
214 char *p;
215 int ret = 1, len;
216
217 opts->name_check = 'n';
218 opts->conversion = 'b';
219 opts->fs_uid = current->uid;
220 opts->fs_gid = current->gid;
221 opts->fs_umask = current->fs->umask;
222 opts->quiet = opts->sys_immutable = opts->dotsOK = opts->showexec = 0;
223 opts->codepage = 0;
224 opts->nocase = 0;
225 opts->utf8 = 0;
226 opts->iocharset = NULL;
227 *debug = *fat = 0;
228
229 if (!options)
230 goto out;
231 save = 0;
232 savep = NULL;
233 for (this_char = strtok(options,","); this_char;
234 this_char = strtok(NULL,",")) {
235 if ((value = strchr(this_char,'=')) != NULL) {
236 save = *value;
237 savep = value;
238 *value++ = 0;
239 }
240 if (!strcmp(this_char,"check") && value) {
241 if (value[0] && !value[1] && strchr("rns",*value))
242 opts->name_check = *value;
243 else if (!strcmp(value,"relaxed"))
244 opts->name_check = 'r';
245 else if (!strcmp(value,"normal"))
246 opts->name_check = 'n';
247 else if (!strcmp(value,"strict"))
248 opts->name_check = 's';
249 else ret = 0;
250 }
251 else if (!strcmp(this_char,"conv") && value) {
252 if (value[0] && !value[1] && strchr("bta",*value))
253 opts->conversion = *value;
254 else if (!strcmp(value,"binary"))
255 opts->conversion = 'b';
256 else if (!strcmp(value,"text"))
257 opts->conversion = 't';
258 else if (!strcmp(value,"auto"))
259 opts->conversion = 'a';
260 else ret = 0;
261 }
262 else if (!strcmp(this_char,"dots")) {
263 opts->dotsOK = 1;
264 }
265 else if (!strcmp(this_char,"nocase")) {
266 opts->nocase = 1;
267 }
268 else if (!strcmp(this_char,"nodots")) {
269 opts->dotsOK = 0;
270 }
271 else if (!strcmp(this_char,"showexec")) {
272 opts->showexec = 1;
273 }
274 else if (!strcmp(this_char,"dotsOK") && value) {
275 if (!strcmp(value,"yes")) opts->dotsOK = 1;
276 else if (!strcmp(value,"no")) opts->dotsOK = 0;
277 else ret = 0;
278 }
279 else if (!strcmp(this_char,"uid")) {
280 if (!value || !*value) ret = 0;
281 else {
282 opts->fs_uid = simple_strtoul(value,&value,0);
283 if (*value) ret = 0;
284 }
285 }
286 else if (!strcmp(this_char,"gid")) {
287 if (!value || !*value) ret= 0;
288 else {
289 opts->fs_gid = simple_strtoul(value,&value,0);
290 if (*value) ret = 0;
291 }
292 }
293 else if (!strcmp(this_char,"umask")) {
294 if (!value || !*value) ret = 0;
295 else {
296 opts->fs_umask = simple_strtoul(value,&value,8);
297 if (*value) ret = 0;
298 }
299 }
300 else if (!strcmp(this_char,"debug")) {
301 if (value) ret = 0;
302 else *debug = 1;
303 }
304 else if (!strcmp(this_char,"fat")) {
305 if (!value || !*value) ret = 0;
306 else {
307 *fat = simple_strtoul(value,&value,0);
308 if (*value || (*fat != 12 && *fat != 16 &&
309 *fat != 32))
310 ret = 0;
311 }
312 }
313 else if (!strcmp(this_char,"quiet")) {
314 if (value) ret = 0;
315 else opts->quiet = 1;
316 }
317 else if (!strcmp(this_char,"blocksize")) {
318 printk("FAT: blocksize option is obsolete, "
319 "not supported now\n");
320 }
321 else if (!strcmp(this_char,"sys_immutable")) {
322 if (value) ret = 0;
323 else opts->sys_immutable = 1;
324 }
325 else if (!strcmp(this_char,"codepage") && value) {
326 opts->codepage = simple_strtoul(value,&value,0);
327 if (*value) ret = 0;
328 else printk ("MSDOS FS: Using codepage %d\n",
329 opts->codepage);
330 }
331 else if (!strcmp(this_char,"iocharset") && value) {
332 p = value;
333 while (*value && *value != ',') value++;
334 len = value - p;
335 if (len) {
336 char * buffer = kmalloc(len+1, GFP_KERNEL);
337 if (buffer) {
338 opts->iocharset = buffer;
339 memcpy(buffer, p, len);
340 buffer[len] = 0;
341 printk("MSDOS FS: IO charset %s\n",
342 buffer);
343 } else
344 ret = 0;
345 }
346 }
347 else if (!strcmp(this_char,"cvf_format")) {
348 if (!value)
349 return 0;
350 strncpy(cvf_format,value,20);
351 }
352 else if (!strcmp(this_char,"cvf_options")) {
353 if (!value)
354 return 0;
355 strncpy(cvf_options,value,100);
356 }
357
358 if (this_char != options) *(this_char-1) = ',';
359 if (value) *savep = save;
360 if (ret == 0)
361 break;
362 }
363 out:
364 return ret;
365 }
366
367 static void fat_read_root(struct inode *inode)
368 {
369 struct super_block *sb = inode->i_sb;
370 struct msdos_sb_info *sbi = MSDOS_SB(sb);
371 int nr;
372
373 INIT_LIST_HEAD(&MSDOS_I(inode)->i_fat_hash);
374 MSDOS_I(inode)->i_location = 0;
375 MSDOS_I(inode)->i_fat_inode = inode;
376 inode->i_uid = sbi->options.fs_uid;
377 inode->i_gid = sbi->options.fs_gid;
378 inode->i_version = ++event;
379 inode->i_generation = 0;
380 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_umask) | S_IFDIR;
381 inode->i_op = sbi->dir_ops;
382 inode->i_fop = &fat_dir_operations;
383 if (sbi->fat_bits == 32) {
384 MSDOS_I(inode)->i_start = sbi->root_cluster;
385 if ((nr = MSDOS_I(inode)->i_start) != 0) {
386 while (nr != -1) {
387 inode->i_size += 1 << sbi->cluster_bits;
388 if (!(nr = fat_access(sb, nr, -1))) {
389 printk("Directory %ld: bad FAT\n",
390 inode->i_ino);
391 break;
392 }
393 }
394 }
395 } else {
396 MSDOS_I(inode)->i_start = 0;
397 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
398 }
399 inode->i_blksize = 1 << sbi->cluster_bits;
400 inode->i_blocks = ((inode->i_size + inode->i_blksize - 1)
401 & ~(inode->i_blksize - 1)) / 512;
402 MSDOS_I(inode)->i_logstart = 0;
403 MSDOS_I(inode)->mmu_private = inode->i_size;
404
405 MSDOS_I(inode)->i_attrs = 0;
406 inode->i_mtime = inode->i_atime = inode->i_ctime = 0;
407 MSDOS_I(inode)->i_ctime_ms = 0;
408 inode->i_nlink = fat_subdirs(inode)+2;
409 }
410
411 /*
412 * a FAT file handle with fhtype 3 is
413 * 0/ i_ino - for fast, reliable lookup if still in the cache
414 * 1/ i_generation - to see if i_ino is still valid
415 * bit 0 == 0 iff directory
416 * 2/ i_location - if ino has changed, but still in cache
417 * 3/ i_logstart - to semi-verify inode found at i_location
418 * 4/ parent->i_logstart - maybe used to hunt for the file on disc
419 *
420 */
421 struct dentry *fat_fh_to_dentry(struct super_block *sb, __u32 *fh,
422 int len, int fhtype, int parent)
423 {
424 struct inode *inode = NULL;
425 struct list_head *lp;
426 struct dentry *result;
427
428 if (fhtype != 3)
429 return NULL;
430 if (len < 5)
431 return NULL;
432 if (parent)
433 return NULL; /* We cannot find the parent,
434 It better just *be* there */
435
436 inode = iget(sb, fh[0]);
437 if (!inode || is_bad_inode(inode) ||
438 inode->i_generation != fh[1]) {
439 if (inode) iput(inode);
440 inode = NULL;
441 }
442 if (!inode) {
443 /* try 2 - see if i_location is in F-d-c
444 * require i_logstart to be the same
445 * Will fail if you truncate and then re-write
446 */
447
448 inode = fat_iget(sb, fh[2]);
449 if (inode && MSDOS_I(inode)->i_logstart != fh[3]) {
450 iput(inode);
451 inode = NULL;
452 }
453 }
454 if (!inode) {
455 /* For now, do nothing
456 * What we could do is:
457 * follow the file starting at fh[4], and record
458 * the ".." entry, and the name of the fh[2] entry.
459 * The follow the ".." file finding the next step up.
460 * This way we build a path to the root of
461 * the tree. If this works, we lookup the path and so
462 * get this inode into the cache.
463 * Finally try the fat_iget lookup again
464 * If that fails, then weare totally out of luck
465 * But all that is for another day
466 */
467 }
468 if (!inode)
469 return ERR_PTR(-ESTALE);
470
471
472 /* now to find a dentry.
473 * If possible, get a well-connected one
474 *
475 * Given the way that we found the inode, it *MUST* be
476 * well-connected, but it is easiest to just copy the
477 * code.
478 */
479 spin_lock(&dcache_lock);
480 for (lp = inode->i_dentry.next; lp != &inode->i_dentry ; lp=lp->next) {
481 result = list_entry(lp,struct dentry, d_alias);
482 if (! (result->d_flags & DCACHE_NFSD_DISCONNECTED)) {
483 dget_locked(result);
484 result->d_vfs_flags |= DCACHE_REFERENCED;
485 spin_unlock(&dcache_lock);
486 iput(inode);
487 return result;
488 }
489 }
490 spin_unlock(&dcache_lock);
491 result = d_alloc_root(inode);
492 if (result == NULL) {
493 iput(inode);
494 return ERR_PTR(-ENOMEM);
495 }
496 result->d_flags |= DCACHE_NFSD_DISCONNECTED;
497 return result;
498
499
500 }
501
502 int fat_dentry_to_fh(struct dentry *de, __u32 *fh, int *lenp, int needparent)
503 {
504 int len = *lenp;
505 struct inode *inode = de->d_inode;
506
507 if (len < 5)
508 return 255; /* no room */
509 *lenp = 5;
510 fh[0] = inode->i_ino;
511 fh[1] = inode->i_generation;
512 fh[2] = MSDOS_I(inode)->i_location;
513 fh[3] = MSDOS_I(inode)->i_logstart;
514 fh[4] = MSDOS_I(de->d_parent->d_inode)->i_logstart;
515 return 3;
516 }
517
518 static struct super_operations fat_sops = {
519 write_inode: fat_write_inode,
520 delete_inode: fat_delete_inode,
521 put_super: fat_put_super,
522 statfs: fat_statfs,
523 clear_inode: fat_clear_inode,
524
525 read_inode: make_bad_inode,
526 fh_to_dentry: fat_fh_to_dentry,
527 dentry_to_fh: fat_dentry_to_fh,
528 };
529
530 /*
531 * Read the super block of an MS-DOS FS.
532 *
533 * Note that this may be called from vfat_read_super
534 * with some fields already initialized.
535 */
536 struct super_block *
537 fat_read_super(struct super_block *sb, void *data, int silent,
538 struct inode_operations *fs_dir_inode_ops)
539 {
540 struct inode *root_inode;
541 struct buffer_head *bh;
542 struct fat_boot_sector *b;
543 struct msdos_sb_info *sbi = MSDOS_SB(sb);
544 char *p;
545 int logical_sector_size, hard_blksize, fat_clusters = 0;
546 unsigned int total_sectors, rootdir_sectors;
547 int fat32, debug, error, fat, cp;
548 struct fat_mount_options opts;
549 char buf[50];
550 int i;
551 char cvf_format[21];
552 char cvf_options[101];
553
554 cvf_format[0] = '\0';
555 cvf_options[0] = '\0';
556 sbi->cvf_format = NULL;
557 sbi->private_data = NULL;
558
559 sbi->dir_ops = fs_dir_inode_ops;
560
561 sb->s_maxbytes = MAX_NON_LFS;
562 sb->s_op = &fat_sops;
563
564 hard_blksize = get_hardsect_size(sb->s_dev);
565 if (!hard_blksize)
566 hard_blksize = 512;
567
568 opts.isvfat = sbi->options.isvfat;
569 if (!parse_options((char *) data, &fat, &debug, &opts,
570 cvf_format, cvf_options))
571 goto out_fail;
572 /* N.B. we should parse directly into the sb structure */
573 memcpy(&(sbi->options), &opts, sizeof(struct fat_mount_options));
574
575 fat_cache_init();
576
577 sb->s_blocksize = hard_blksize;
578 set_blocksize(sb->s_dev, hard_blksize);
579 bh = bread(sb->s_dev, 0, sb->s_blocksize);
580 if (bh == NULL) {
581 printk("FAT: unable to read boot sector\n");
582 goto out_fail;
583 }
584
585 /*
586 * The DOS3 partition size limit is *not* 32M as many people think.
587 * Instead, it is 64K sectors (with the usual sector size being
588 * 512 bytes, leading to a 32M limit).
589 *
590 * DOS 3 partition managers got around this problem by faking a
591 * larger sector size, ie treating multiple physical sectors as
592 * a single logical sector.
593 *
594 * We can accommodate this scheme by adjusting our cluster size,
595 * fat_start, and data_start by an appropriate value.
596 *
597 * (by Drew Eckhardt)
598 */
599
600
601 b = (struct fat_boot_sector *) bh->b_data;
602 logical_sector_size =
603 CF_LE_W(get_unaligned((unsigned short *) &b->sector_size));
604 if (!logical_sector_size
605 || (logical_sector_size & (logical_sector_size - 1))) {
606 printk("FAT: bogus logical sector size %d\n",
607 logical_sector_size);
608 brelse(bh);
609 goto out_invalid;
610 }
611
612 sbi->cluster_size = b->cluster_size;
613 if (!sbi->cluster_size
614 || (sbi->cluster_size & (sbi->cluster_size - 1))) {
615 printk("FAT: bogus cluster size %d\n", sbi->cluster_size);
616 brelse(bh);
617 goto out_invalid;
618 }
619
620 if (logical_sector_size < hard_blksize) {
621 printk("FAT: logical sector size too small for device"
622 " (logical sector size = %d)\n", logical_sector_size);
623 brelse(bh);
624 goto out_invalid;
625 }
626
627 sbi->cluster_bits = ffs(logical_sector_size * sbi->cluster_size) - 1;
628 sbi->fats = b->fats;
629 sbi->fat_start = CF_LE_W(b->reserved);
630 if (!b->fat_length && b->fat32_length) {
631 struct fat_boot_fsinfo *fsinfo;
632 struct buffer_head *fsinfo_bh;
633 int fsinfo_block, fsinfo_offset;
634
635 /* Must be FAT32 */
636 fat32 = 1;
637 sbi->fat_length = CF_LE_L(b->fat32_length);
638 sbi->root_cluster = CF_LE_L(b->root_cluster);
639
640 sbi->fsinfo_sector = CF_LE_W(b->info_sector);
641 /* MC - if info_sector is 0, don't multiply by 0 */
642 if (sbi->fsinfo_sector == 0)
643 sbi->fsinfo_sector = 1;
644
645 fsinfo_block =
646 (sbi->fsinfo_sector * logical_sector_size) / hard_blksize;
647 fsinfo_offset =
648 (sbi->fsinfo_sector * logical_sector_size) % hard_blksize;
649 fsinfo_bh = bh;
650 if (bh->b_blocknr != fsinfo_block) {
651 fsinfo_bh = bread(sb->s_dev, fsinfo_block, hard_blksize);
652 if (fsinfo_bh == NULL) {
653 printk("FAT: bread failed, FSINFO block"
654 " (blocknr = %d)\n", fsinfo_block);
655 brelse(bh);
656 goto out_invalid;
657 }
658 }
659 fsinfo = (struct fat_boot_fsinfo *)&fsinfo_bh->b_data[fsinfo_offset];
660 if (!IS_FSINFO(fsinfo)) {
661 printk("FAT: Did not find valid FSINFO signature.\n"
662 "Found signature1 0x%x signature2 0x%x sector=%ld.\n",
663 CF_LE_L(fsinfo->signature1),
664 CF_LE_L(fsinfo->signature2),
665 sbi->fsinfo_sector);
666 } else {
667 sbi->free_clusters = CF_LE_L(fsinfo->free_clusters);
668 }
669
670 if (bh->b_blocknr != fsinfo_block)
671 brelse(fsinfo_bh);
672 } else {
673 fat32 = 0;
674 sbi->fat_length = CF_LE_W(b->fat_length);
675 sbi->root_cluster = 0;
676 sbi->free_clusters = -1; /* Don't know yet */
677 }
678
679 sbi->dir_per_block = logical_sector_size / sizeof(struct msdos_dir_entry);
680 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
681
682 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
683 sbi->dir_entries =
684 CF_LE_W(get_unaligned((unsigned short *)&b->dir_entries));
685 rootdir_sectors = sbi->dir_entries
686 * sizeof(struct msdos_dir_entry) / logical_sector_size;
687 sbi->data_start = sbi->dir_start + rootdir_sectors;
688 total_sectors = CF_LE_W(get_unaligned((unsigned short *)&b->sectors));
689 if (total_sectors == 0)
690 total_sectors = CF_LE_L(b->total_sect);
691 sbi->clusters = (total_sectors - sbi->data_start) / sbi->cluster_size;
692
693 error = 0;
694 if (!error) {
695 sbi->fat_bits = fat32 ? 32 :
696 (fat ? fat :
697 (sbi->clusters > MSDOS_FAT12 ? 16 : 12));
698 fat_clusters =
699 sbi->fat_length * logical_sector_size * 8 / sbi->fat_bits;
700 error = !sbi->fats || (sbi->dir_entries & (sbi->dir_per_block - 1))
701 || sbi->clusters + 2 > fat_clusters + MSDOS_MAX_EXTRA
702 || logical_sector_size < 512
703 || PAGE_CACHE_SIZE < logical_sector_size
704 || !b->secs_track || !b->heads;
705 }
706 brelse(bh);
707
708 sb->s_blocksize = logical_sector_size;
709 sb->s_blocksize_bits = ffs(logical_sector_size) - 1;
710 set_blocksize(sb->s_dev, sb->s_blocksize);
711 sbi->cvf_format = &default_cvf;
712 if (!strcmp(cvf_format, "none"))
713 i = -1;
714 else
715 i = detect_cvf(sb,cvf_format);
716 if (i >= 0)
717 error = cvf_formats[i]->mount_cvf(sb, cvf_options);
718 if (error || debug) {
719 /* The MSDOS_CAN_BMAP is obsolete, but left just to remember */
720 printk("[MS-DOS FS Rel. 12,FAT %d,check=%c,conv=%c,"
721 "uid=%d,gid=%d,umask=%03o%s]\n",
722 sbi->fat_bits,opts.name_check,
723 opts.conversion,opts.fs_uid,opts.fs_gid,opts.fs_umask,
724 MSDOS_CAN_BMAP(sbi) ? ",bmap" : "");
725 printk("[me=0x%x,cs=%d,#f=%d,fs=%d,fl=%ld,ds=%ld,de=%d,data=%ld,"
726 "se=%u,ts=%u,ls=%d,rc=%ld,fc=%u]\n",
727 b->media, sbi->cluster_size, sbi->fats,
728 sbi->fat_start, sbi->fat_length, sbi->dir_start,
729 sbi->dir_entries, sbi->data_start,
730 CF_LE_W(get_unaligned((unsigned short *)&b->sectors)),
731 CF_LE_L(b->total_sect), logical_sector_size,
732 sbi->root_cluster, sbi->free_clusters);
733 printk ("hard sector size = %d\n", hard_blksize);
734 }
735 if (i < 0)
736 if (sbi->clusters + 2 > fat_clusters)
737 sbi->clusters = fat_clusters - 2;
738 if (error)
739 goto out_invalid;
740
741 sb->s_magic = MSDOS_SUPER_MAGIC;
742 /* set up enough so that it can read an inode */
743 init_waitqueue_head(&sbi->fat_wait);
744 init_MUTEX(&sbi->fat_lock);
745 sbi->prev_free = 0;
746
747 cp = opts.codepage ? opts.codepage : 437;
748 sprintf(buf, "cp%d", cp);
749 sbi->nls_disk = load_nls(buf);
750 if (! sbi->nls_disk) {
751 /* Fail only if explicit charset specified */
752 if (opts.codepage != 0)
753 goto out_fail;
754 sbi->options.codepage = 0; /* already 0?? */
755 sbi->nls_disk = load_nls_default();
756 }
757
758 sbi->nls_io = NULL;
759 if (sbi->options.isvfat && !opts.utf8) {
760 p = opts.iocharset ? opts.iocharset : CONFIG_NLS_DEFAULT;
761 sbi->nls_io = load_nls(p);
762 if (! sbi->nls_io)
763 /* Fail only if explicit charset specified */
764 if (opts.iocharset)
765 goto out_unload_nls;
766 }
767 if (! sbi->nls_io)
768 sbi->nls_io = load_nls_default();
769
770 root_inode = new_inode(sb);
771 if (!root_inode)
772 goto out_unload_nls;
773 root_inode->i_ino = MSDOS_ROOT_INO;
774 fat_read_root(root_inode);
775 insert_inode_hash(root_inode);
776 sb->s_root = d_alloc_root(root_inode);
777 if (!sb->s_root)
778 goto out_no_root;
779 if(i >= 0) {
780 sbi->cvf_format = cvf_formats[i];
781 ++cvf_format_use_count[i];
782 }
783 return sb;
784
785 out_no_root:
786 printk("FAT: get root inode failed\n");
787 iput(root_inode);
788 unload_nls(sbi->nls_io);
789 out_unload_nls:
790 unload_nls(sbi->nls_disk);
791 goto out_fail;
792 out_invalid:
793 if (!silent) {
794 printk("VFS: Can't find a valid FAT filesystem on dev %s.\n",
795 kdevname(sb->s_dev));
796 }
797 out_fail:
798 if (opts.iocharset) {
799 printk("FAT: freeing iocharset=%s\n", opts.iocharset);
800 kfree(opts.iocharset);
801 }
802 if(sbi->private_data)
803 kfree(sbi->private_data);
804 sbi->private_data = NULL;
805
806 return NULL;
807 }
808
809 int fat_statfs(struct super_block *sb,struct statfs *buf)
810 {
811 int free,nr;
812
813 if (MSDOS_SB(sb)->cvf_format &&
814 MSDOS_SB(sb)->cvf_format->cvf_statfs)
815 return MSDOS_SB(sb)->cvf_format->cvf_statfs(sb,buf,
816 sizeof(struct statfs));
817
818 lock_fat(sb);
819 if (MSDOS_SB(sb)->free_clusters != -1)
820 free = MSDOS_SB(sb)->free_clusters;
821 else {
822 free = 0;
823 for (nr = 2; nr < MSDOS_SB(sb)->clusters+2; nr++)
824 if (!fat_access(sb,nr,-1)) free++;
825 MSDOS_SB(sb)->free_clusters = free;
826 }
827 unlock_fat(sb);
828 buf->f_type = sb->s_magic;
829 buf->f_bsize = 1 << MSDOS_SB(sb)->cluster_bits;
830 buf->f_blocks = MSDOS_SB(sb)->clusters;
831 buf->f_bfree = free;
832 buf->f_bavail = free;
833 buf->f_namelen = MSDOS_SB(sb)->options.isvfat ? 260 : 12;
834 return 0;
835 }
836
837 static int is_exec(char *extension)
838 {
839 char *exe_extensions = "EXECOMBAT", *walk;
840
841 for (walk = exe_extensions; *walk; walk += 3)
842 if (!strncmp(extension, walk, 3))
843 return 1;
844 return 0;
845 }
846
847 static int fat_writepage(struct page *page)
848 {
849 return block_write_full_page(page,fat_get_block);
850 }
851 static int fat_readpage(struct file *file, struct page *page)
852 {
853 return block_read_full_page(page,fat_get_block);
854 }
855 static int fat_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
856 {
857 return cont_prepare_write(page,from,to,fat_get_block,
858 &MSDOS_I(page->mapping->host)->mmu_private);
859 }
860 static int _fat_bmap(struct address_space *mapping, long block)
861 {
862 return generic_block_bmap(mapping,block,fat_get_block);
863 }
864 static struct address_space_operations fat_aops = {
865 readpage: fat_readpage,
866 writepage: fat_writepage,
867 sync_page: block_sync_page,
868 prepare_write: fat_prepare_write,
869 commit_write: generic_commit_write,
870 bmap: _fat_bmap
871 };
872
873 /* doesn't deal with root inode */
874 static void fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
875 {
876 struct super_block *sb = inode->i_sb;
877 struct msdos_sb_info *sbi = MSDOS_SB(sb);
878 int nr;
879
880 INIT_LIST_HEAD(&MSDOS_I(inode)->i_fat_hash);
881 MSDOS_I(inode)->i_location = 0;
882 MSDOS_I(inode)->i_fat_inode = inode;
883 inode->i_uid = sbi->options.fs_uid;
884 inode->i_gid = sbi->options.fs_gid;
885 inode->i_version = ++event;
886 inode->i_generation = CURRENT_TIME;
887
888 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
889 inode->i_generation &= ~1;
890 inode->i_mode = MSDOS_MKMODE(de->attr,S_IRWXUGO &
891 ~sbi->options.fs_umask) | S_IFDIR;
892 inode->i_op = sbi->dir_ops;
893 inode->i_fop = &fat_dir_operations;
894
895 MSDOS_I(inode)->i_start = CF_LE_W(de->start);
896 if (sbi->fat_bits == 32) {
897 MSDOS_I(inode)->i_start |=
898 (CF_LE_W(de->starthi) << 16);
899 }
900 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
901 inode->i_nlink = fat_subdirs(inode);
902 /* includes .., compensating for "self" */
903 #ifdef DEBUG
904 if (!inode->i_nlink) {
905 printk("directory %d: i_nlink == 0\n",inode->i_ino);
906 inode->i_nlink = 1;
907 }
908 #endif
909 if ((nr = MSDOS_I(inode)->i_start) != 0)
910 while (nr != -1) {
911 inode->i_size += 1 << sbi->cluster_bits;
912 if (!(nr = fat_access(sb, nr, -1))) {
913 printk("Directory %ld: bad FAT\n",
914 inode->i_ino);
915 break;
916 }
917 }
918 MSDOS_I(inode)->mmu_private = inode->i_size;
919 } else { /* not a directory */
920 inode->i_generation |= 1;
921 inode->i_mode = MSDOS_MKMODE(de->attr,
922 ((sbi->options.showexec &&
923 !is_exec(de->ext))
924 ? S_IRUGO|S_IWUGO : S_IRWXUGO)
925 & ~sbi->options.fs_umask) | S_IFREG;
926 MSDOS_I(inode)->i_start = CF_LE_W(de->start);
927 if (sbi->fat_bits == 32) {
928 MSDOS_I(inode)->i_start |=
929 (CF_LE_W(de->starthi) << 16);
930 }
931 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
932 inode->i_size = CF_LE_L(de->size);
933 inode->i_op = &fat_file_inode_operations;
934 inode->i_fop = &fat_file_operations;
935 inode->i_mapping->a_ops = &fat_aops;
936 MSDOS_I(inode)->mmu_private = inode->i_size;
937 }
938 if(de->attr & ATTR_SYS)
939 if (sbi->options.sys_immutable)
940 inode->i_flags |= S_IMMUTABLE;
941 MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED;
942 /* this is as close to the truth as we can get ... */
943 inode->i_blksize = 1 << sbi->cluster_bits;
944 inode->i_blocks = ((inode->i_size + inode->i_blksize - 1)
945 & ~(inode->i_blksize - 1)) / 512;
946 inode->i_mtime = inode->i_atime =
947 date_dos2unix(CF_LE_W(de->time),CF_LE_W(de->date));
948 inode->i_ctime =
949 MSDOS_SB(sb)->options.isvfat
950 ? date_dos2unix(CF_LE_W(de->ctime),CF_LE_W(de->cdate))
951 : inode->i_mtime;
952 MSDOS_I(inode)->i_ctime_ms = de->ctime_ms;
953 }
954
955 void fat_write_inode(struct inode *inode, int wait)
956 {
957 struct super_block *sb = inode->i_sb;
958 struct buffer_head *bh;
959 struct msdos_dir_entry *raw_entry;
960 int i_pos;
961
962 retry:
963 i_pos = MSDOS_I(inode)->i_location;
964 if (inode->i_ino == MSDOS_ROOT_INO || !i_pos) {
965 return;
966 }
967 lock_kernel();
968 if (!(bh = fat_bread(sb, i_pos >> MSDOS_SB(sb)->dir_per_block_bits))) {
969 printk("dev = %s, ino = %d\n", kdevname(inode->i_dev), i_pos);
970 fat_fs_panic(sb, "msdos_write_inode: unable to read i-node block");
971 unlock_kernel();
972 return;
973 }
974 spin_lock(&fat_inode_lock);
975 if (i_pos != MSDOS_I(inode)->i_location) {
976 spin_unlock(&fat_inode_lock);
977 fat_brelse(sb, bh);
978 unlock_kernel();
979 goto retry;
980 }
981
982 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
983 [i_pos & (MSDOS_SB(sb)->dir_per_block - 1)];
984 if (S_ISDIR(inode->i_mode)) {
985 raw_entry->attr = ATTR_DIR;
986 raw_entry->size = 0;
987 }
988 else {
989 raw_entry->attr = ATTR_NONE;
990 raw_entry->size = CT_LE_L(inode->i_size);
991 }
992 raw_entry->attr |= MSDOS_MKATTR(inode->i_mode) |
993 MSDOS_I(inode)->i_attrs;
994 raw_entry->start = CT_LE_W(MSDOS_I(inode)->i_logstart);
995 raw_entry->starthi = CT_LE_W(MSDOS_I(inode)->i_logstart >> 16);
996 fat_date_unix2dos(inode->i_mtime,&raw_entry->time,&raw_entry->date);
997 raw_entry->time = CT_LE_W(raw_entry->time);
998 raw_entry->date = CT_LE_W(raw_entry->date);
999 if (MSDOS_SB(sb)->options.isvfat) {
1000 fat_date_unix2dos(inode->i_ctime,&raw_entry->ctime,&raw_entry->cdate);
1001 raw_entry->ctime_ms = MSDOS_I(inode)->i_ctime_ms;
1002 raw_entry->ctime = CT_LE_W(raw_entry->ctime);
1003 raw_entry->cdate = CT_LE_W(raw_entry->cdate);
1004 }
1005 spin_unlock(&fat_inode_lock);
1006 fat_mark_buffer_dirty(sb, bh);
1007 fat_brelse(sb, bh);
1008 unlock_kernel();
1009 }
1010
1011
1012 int fat_notify_change(struct dentry * dentry, struct iattr * attr)
1013 {
1014 struct super_block *sb = dentry->d_sb;
1015 struct inode *inode = dentry->d_inode;
1016 int error;
1017
1018 /* FAT cannot truncate to a longer file */
1019 if (attr->ia_valid & ATTR_SIZE) {
1020 if (attr->ia_size > inode->i_size)
1021 return -EPERM;
1022 }
1023
1024 error = inode_change_ok(inode, attr);
1025 if (error)
1026 return MSDOS_SB(sb)->options.quiet ? 0 : error;
1027
1028 if (((attr->ia_valid & ATTR_UID) &&
1029 (attr->ia_uid != MSDOS_SB(sb)->options.fs_uid)) ||
1030 ((attr->ia_valid & ATTR_GID) &&
1031 (attr->ia_gid != MSDOS_SB(sb)->options.fs_gid)) ||
1032 ((attr->ia_valid & ATTR_MODE) &&
1033 (attr->ia_mode & ~MSDOS_VALID_MODE)))
1034 error = -EPERM;
1035
1036 if (error)
1037 return MSDOS_SB(sb)->options.quiet ? 0 : error;
1038
1039 inode_setattr(inode, attr);
1040
1041 if (S_ISDIR(inode->i_mode))
1042 inode->i_mode |= S_IXUGO;
1043
1044 inode->i_mode = ((inode->i_mode & S_IFMT) | ((((inode->i_mode & S_IRWXU
1045 & ~MSDOS_SB(sb)->options.fs_umask) | S_IRUSR) >> 6)*S_IXUGO)) &
1046 ~MSDOS_SB(sb)->options.fs_umask;
1047 return 0;
1048 }
1049