blob: 932c8d6d1f5477a504c496810b6427b37ce0777f [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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/module.h>
14#include <linux/init.h>
15#include <linux/time.h>
16#include <linux/slab.h>
17#include <linux/smp_lock.h>
18#include <linux/seq_file.h>
19#include <linux/msdos_fs.h>
20#include <linux/pagemap.h>
OGAWA Hirofumia5425d22006-01-08 01:02:10 -080021#include <linux/mpage.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/buffer_head.h>
23#include <linux/mount.h>
24#include <linux/vfs.h>
25#include <linux/parser.h>
26#include <asm/unaligned.h>
27
28#ifndef CONFIG_FAT_DEFAULT_IOCHARSET
29/* if user don't select VFAT, this is undefined. */
30#define CONFIG_FAT_DEFAULT_IOCHARSET ""
31#endif
32
33static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
34static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
35
36
37static int fat_add_cluster(struct inode *inode)
38{
39 int err, cluster;
40
41 err = fat_alloc_clusters(inode, &cluster, 1);
42 if (err)
43 return err;
44 /* FIXME: this cluster should be added after data of this
45 * cluster is writed */
46 err = fat_chain_add(inode, cluster, 1);
47 if (err)
48 fat_free_clusters(inode, cluster);
49 return err;
50}
51
52static int fat_get_block(struct inode *inode, sector_t iblock,
53 struct buffer_head *bh_result, int create)
54{
55 struct super_block *sb = inode->i_sb;
56 sector_t phys;
57 int err;
58
59 err = fat_bmap(inode, iblock, &phys);
60 if (err)
61 return err;
62 if (phys) {
63 map_bh(bh_result, sb, phys);
64 return 0;
65 }
66 if (!create)
67 return 0;
68 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
69 fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)",
70 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
71 return -EIO;
72 }
73 if (!((unsigned long)iblock & (MSDOS_SB(sb)->sec_per_clus - 1))) {
74 err = fat_add_cluster(inode);
75 if (err)
76 return err;
77 }
78 MSDOS_I(inode)->mmu_private += sb->s_blocksize;
79 err = fat_bmap(inode, iblock, &phys);
80 if (err)
81 return err;
82 if (!phys)
83 BUG();
84 set_buffer_new(bh_result);
85 map_bh(bh_result, sb, phys);
86 return 0;
87}
88
89static int fat_writepage(struct page *page, struct writeback_control *wbc)
90{
91 return block_write_full_page(page, fat_get_block, wbc);
92}
93
OGAWA Hirofumia5425d22006-01-08 01:02:10 -080094static int fat_writepages(struct address_space *mapping,
95 struct writeback_control *wbc)
96{
97 return mpage_writepages(mapping, wbc, fat_get_block);
98}
99
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100static int fat_readpage(struct file *file, struct page *page)
101{
OGAWA Hirofumia5425d22006-01-08 01:02:10 -0800102 return mpage_readpage(page, fat_get_block);
103}
104
105static int fat_readpages(struct file *file, struct address_space *mapping,
106 struct list_head *pages, unsigned nr_pages)
107{
108 return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109}
110
111static int fat_prepare_write(struct file *file, struct page *page,
112 unsigned from, unsigned to)
113{
114 return cont_prepare_write(page, from, to, fat_get_block,
115 &MSDOS_I(page->mapping->host)->mmu_private);
116}
117
OGAWA Hirofumief402262005-09-16 19:28:13 -0700118static int fat_commit_write(struct file *file, struct page *page,
119 unsigned from, unsigned to)
120{
121 struct inode *inode = page->mapping->host;
122 int err = generic_commit_write(file, page, from, to);
123 if (!err && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
124 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
125 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
126 mark_inode_dirty(inode);
127 }
128 return err;
129}
130
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
132{
133 return generic_block_bmap(mapping, block, fat_get_block);
134}
135
136static struct address_space_operations fat_aops = {
137 .readpage = fat_readpage,
OGAWA Hirofumia5425d22006-01-08 01:02:10 -0800138 .readpages = fat_readpages,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 .writepage = fat_writepage,
OGAWA Hirofumia5425d22006-01-08 01:02:10 -0800140 .writepages = fat_writepages,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 .sync_page = block_sync_page,
142 .prepare_write = fat_prepare_write,
OGAWA Hirofumief402262005-09-16 19:28:13 -0700143 .commit_write = fat_commit_write,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 .bmap = _fat_bmap
145};
146
147/*
148 * New FAT inode stuff. We do the following:
149 * a) i_ino is constant and has nothing with on-disk location.
150 * b) FAT manages its own cache of directory entries.
151 * c) *This* cache is indexed by on-disk location.
152 * d) inode has an associated directory entry, all right, but
153 * it may be unhashed.
154 * e) currently entries are stored within struct inode. That should
155 * change.
156 * f) we deal with races in the following way:
157 * 1. readdir() and lookup() do FAT-dir-cache lookup.
158 * 2. rename() unhashes the F-d-c entry and rehashes it in
159 * a new place.
160 * 3. unlink() and rmdir() unhash F-d-c entry.
161 * 4. fat_write_inode() checks whether the thing is unhashed.
162 * If it is we silently return. If it isn't we do bread(),
163 * check if the location is still valid and retry if it
164 * isn't. Otherwise we do changes.
165 * 5. Spinlock is used to protect hash/unhash/location check/lookup
166 * 6. fat_clear_inode() unhashes the F-d-c entry.
167 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
168 * and consider negative result as cache miss.
169 */
170
171static void fat_hash_init(struct super_block *sb)
172{
173 struct msdos_sb_info *sbi = MSDOS_SB(sb);
174 int i;
175
176 spin_lock_init(&sbi->inode_hash_lock);
177 for (i = 0; i < FAT_HASH_SIZE; i++)
178 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
179}
180
181static inline unsigned long fat_hash(struct super_block *sb, loff_t i_pos)
182{
183 unsigned long tmp = (unsigned long)i_pos | (unsigned long) sb;
184 tmp = tmp + (tmp >> FAT_HASH_BITS) + (tmp >> FAT_HASH_BITS * 2);
185 return tmp & FAT_HASH_MASK;
186}
187
188void fat_attach(struct inode *inode, loff_t i_pos)
189{
190 struct super_block *sb = inode->i_sb;
191 struct msdos_sb_info *sbi = MSDOS_SB(sb);
192
193 spin_lock(&sbi->inode_hash_lock);
194 MSDOS_I(inode)->i_pos = i_pos;
195 hlist_add_head(&MSDOS_I(inode)->i_fat_hash,
196 sbi->inode_hashtable + fat_hash(sb, i_pos));
197 spin_unlock(&sbi->inode_hash_lock);
198}
199
OGAWA Hirofumi7c709d02006-01-08 01:02:10 -0800200EXPORT_SYMBOL_GPL(fat_attach);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201
202void fat_detach(struct inode *inode)
203{
204 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
205 spin_lock(&sbi->inode_hash_lock);
206 MSDOS_I(inode)->i_pos = 0;
207 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
208 spin_unlock(&sbi->inode_hash_lock);
209}
210
OGAWA Hirofumi7c709d02006-01-08 01:02:10 -0800211EXPORT_SYMBOL_GPL(fat_detach);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212
213struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
214{
215 struct msdos_sb_info *sbi = MSDOS_SB(sb);
216 struct hlist_head *head = sbi->inode_hashtable + fat_hash(sb, i_pos);
217 struct hlist_node *_p;
218 struct msdos_inode_info *i;
219 struct inode *inode = NULL;
220
221 spin_lock(&sbi->inode_hash_lock);
222 hlist_for_each_entry(i, _p, head, i_fat_hash) {
223 BUG_ON(i->vfs_inode.i_sb != sb);
224 if (i->i_pos != i_pos)
225 continue;
226 inode = igrab(&i->vfs_inode);
227 if (inode)
228 break;
229 }
230 spin_unlock(&sbi->inode_hash_lock);
231 return inode;
232}
233
234static int is_exec(unsigned char *extension)
235{
236 unsigned char *exe_extensions = "EXECOMBAT", *walk;
237
238 for (walk = exe_extensions; *walk; walk += 3)
239 if (!strncmp(extension, walk, 3))
240 return 1;
241 return 0;
242}
243
244static int fat_calc_dir_size(struct inode *inode)
245{
246 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
247 int ret, fclus, dclus;
248
249 inode->i_size = 0;
250 if (MSDOS_I(inode)->i_start == 0)
251 return 0;
252
253 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
254 if (ret < 0)
255 return ret;
256 inode->i_size = (fclus + 1) << sbi->cluster_bits;
257
258 return 0;
259}
260
261/* doesn't deal with root inode */
262static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
263{
264 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
265 int error;
266
267 MSDOS_I(inode)->i_pos = 0;
268 inode->i_uid = sbi->options.fs_uid;
269 inode->i_gid = sbi->options.fs_gid;
270 inode->i_version++;
271 inode->i_generation = get_seconds();
272
273 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
274 inode->i_generation &= ~1;
275 inode->i_mode = MSDOS_MKMODE(de->attr,
276 S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR;
277 inode->i_op = sbi->dir_ops;
278 inode->i_fop = &fat_dir_operations;
279
280 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
281 if (sbi->fat_bits == 32)
282 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
283
284 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
285 error = fat_calc_dir_size(inode);
286 if (error < 0)
287 return error;
288 MSDOS_I(inode)->mmu_private = inode->i_size;
289
290 inode->i_nlink = fat_subdirs(inode);
291 } else { /* not a directory */
292 inode->i_generation |= 1;
293 inode->i_mode = MSDOS_MKMODE(de->attr,
294 ((sbi->options.showexec &&
295 !is_exec(de->ext))
296 ? S_IRUGO|S_IWUGO : S_IRWXUGO)
297 & ~sbi->options.fs_fmask) | S_IFREG;
298 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
299 if (sbi->fat_bits == 32)
300 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
301
302 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
303 inode->i_size = le32_to_cpu(de->size);
304 inode->i_op = &fat_file_inode_operations;
305 inode->i_fop = &fat_file_operations;
306 inode->i_mapping->a_ops = &fat_aops;
307 MSDOS_I(inode)->mmu_private = inode->i_size;
308 }
309 if (de->attr & ATTR_SYS) {
310 if (sbi->options.sys_immutable)
311 inode->i_flags |= S_IMMUTABLE;
312 }
313 MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED;
314 /* this is as close to the truth as we can get ... */
315 inode->i_blksize = sbi->cluster_size;
316 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
317 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
Stephane Kardas62a36c42005-09-21 09:55:45 -0700318 inode->i_mtime.tv_sec =
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319 date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date));
Stephane Kardas62a36c42005-09-21 09:55:45 -0700320 inode->i_mtime.tv_nsec = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 if (sbi->options.isvfat) {
322 int secs = de->ctime_cs / 100;
323 int csecs = de->ctime_cs % 100;
324 inode->i_ctime.tv_sec =
325 date_dos2unix(le16_to_cpu(de->ctime),
326 le16_to_cpu(de->cdate)) + secs;
327 inode->i_ctime.tv_nsec = csecs * 10000000;
Stephane Kardas62a36c42005-09-21 09:55:45 -0700328 inode->i_atime.tv_sec =
329 date_dos2unix(le16_to_cpu(0), le16_to_cpu(de->adate));
330 inode->i_atime.tv_nsec = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 } else
Stephane Kardas62a36c42005-09-21 09:55:45 -0700332 inode->i_ctime = inode->i_atime = inode->i_mtime;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333
334 return 0;
335}
336
337struct inode *fat_build_inode(struct super_block *sb,
338 struct msdos_dir_entry *de, loff_t i_pos)
339{
340 struct inode *inode;
341 int err;
342
343 inode = fat_iget(sb, i_pos);
344 if (inode)
345 goto out;
346 inode = new_inode(sb);
347 if (!inode) {
348 inode = ERR_PTR(-ENOMEM);
349 goto out;
350 }
351 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
352 inode->i_version = 1;
353 err = fat_fill_inode(inode, de);
354 if (err) {
355 iput(inode);
356 inode = ERR_PTR(err);
357 goto out;
358 }
359 fat_attach(inode, i_pos);
360 insert_inode_hash(inode);
361out:
362 return inode;
363}
364
OGAWA Hirofumi7c709d02006-01-08 01:02:10 -0800365EXPORT_SYMBOL_GPL(fat_build_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366
367static void fat_delete_inode(struct inode *inode)
368{
Mark Fashehfef26652005-09-09 13:01:31 -0700369 truncate_inode_pages(&inode->i_data, 0);
370
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 if (!is_bad_inode(inode)) {
372 inode->i_size = 0;
373 fat_truncate(inode);
374 }
375 clear_inode(inode);
376}
377
378static void fat_clear_inode(struct inode *inode)
379{
380 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
381
382 if (is_bad_inode(inode))
383 return;
384 lock_kernel();
385 spin_lock(&sbi->inode_hash_lock);
386 fat_cache_inval_inode(inode);
387 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
388 spin_unlock(&sbi->inode_hash_lock);
389 unlock_kernel();
390}
391
OGAWA Hirofumia6bf6b22006-01-08 01:02:08 -0800392static void fat_write_super(struct super_block *sb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393{
OGAWA Hirofumia6bf6b22006-01-08 01:02:08 -0800394 sb->s_dirt = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395
396 if (!(sb->s_flags & MS_RDONLY))
397 fat_clusters_flush(sb);
OGAWA Hirofumia6bf6b22006-01-08 01:02:08 -0800398}
399
400static void fat_put_super(struct super_block *sb)
401{
402 struct msdos_sb_info *sbi = MSDOS_SB(sb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403
404 if (sbi->nls_disk) {
405 unload_nls(sbi->nls_disk);
406 sbi->nls_disk = NULL;
407 sbi->options.codepage = fat_default_codepage;
408 }
409 if (sbi->nls_io) {
410 unload_nls(sbi->nls_io);
411 sbi->nls_io = NULL;
412 }
413 if (sbi->options.iocharset != fat_default_iocharset) {
414 kfree(sbi->options.iocharset);
415 sbi->options.iocharset = fat_default_iocharset;
416 }
417
418 sb->s_fs_info = NULL;
419 kfree(sbi);
420}
421
422static kmem_cache_t *fat_inode_cachep;
423
424static struct inode *fat_alloc_inode(struct super_block *sb)
425{
426 struct msdos_inode_info *ei;
427 ei = kmem_cache_alloc(fat_inode_cachep, SLAB_KERNEL);
428 if (!ei)
429 return NULL;
430 return &ei->vfs_inode;
431}
432
433static void fat_destroy_inode(struct inode *inode)
434{
435 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
436}
437
438static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
439{
440 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
441
442 if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
443 SLAB_CTOR_CONSTRUCTOR) {
444 spin_lock_init(&ei->cache_lru_lock);
445 ei->nr_caches = 0;
446 ei->cache_valid_id = FAT_CACHE_VALID + 1;
447 INIT_LIST_HEAD(&ei->cache_lru);
448 INIT_HLIST_NODE(&ei->i_fat_hash);
449 inode_init_once(&ei->vfs_inode);
450 }
451}
452
453static int __init fat_init_inodecache(void)
454{
455 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
456 sizeof(struct msdos_inode_info),
457 0, SLAB_RECLAIM_ACCOUNT,
458 init_once, NULL);
459 if (fat_inode_cachep == NULL)
460 return -ENOMEM;
461 return 0;
462}
463
464static void __exit fat_destroy_inodecache(void)
465{
466 if (kmem_cache_destroy(fat_inode_cachep))
467 printk(KERN_INFO "fat_inode_cache: not all structures were freed\n");
468}
469
470static int fat_remount(struct super_block *sb, int *flags, char *data)
471{
472 struct msdos_sb_info *sbi = MSDOS_SB(sb);
473 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
474 return 0;
475}
476
477static int fat_statfs(struct super_block *sb, struct kstatfs *buf)
478{
479 struct msdos_sb_info *sbi = MSDOS_SB(sb);
480
481 /* If the count of free cluster is still unknown, counts it here. */
482 if (sbi->free_clusters == -1) {
483 int err = fat_count_free_clusters(sb);
484 if (err)
485 return err;
486 }
487
488 buf->f_type = sb->s_magic;
489 buf->f_bsize = sbi->cluster_size;
490 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
491 buf->f_bfree = sbi->free_clusters;
492 buf->f_bavail = sbi->free_clusters;
493 buf->f_namelen = sbi->options.isvfat ? 260 : 12;
494
495 return 0;
496}
497
498static int fat_write_inode(struct inode *inode, int wait)
499{
500 struct super_block *sb = inode->i_sb;
501 struct msdos_sb_info *sbi = MSDOS_SB(sb);
502 struct buffer_head *bh;
503 struct msdos_dir_entry *raw_entry;
504 loff_t i_pos;
505 int err = 0;
506
507retry:
508 i_pos = MSDOS_I(inode)->i_pos;
509 if (inode->i_ino == MSDOS_ROOT_INO || !i_pos)
510 return 0;
511
512 lock_kernel();
513 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
514 if (!bh) {
515 printk(KERN_ERR "FAT: unable to read inode block "
516 "for updating (i_pos %lld)\n", i_pos);
517 err = -EIO;
518 goto out;
519 }
520 spin_lock(&sbi->inode_hash_lock);
521 if (i_pos != MSDOS_I(inode)->i_pos) {
522 spin_unlock(&sbi->inode_hash_lock);
523 brelse(bh);
524 unlock_kernel();
525 goto retry;
526 }
527
528 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
529 [i_pos & (sbi->dir_per_block - 1)];
530 if (S_ISDIR(inode->i_mode))
531 raw_entry->size = 0;
532 else
533 raw_entry->size = cpu_to_le32(inode->i_size);
534 raw_entry->attr = fat_attr(inode);
535 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
536 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
537 fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date);
538 if (sbi->options.isvfat) {
Stephane Kardas62a36c42005-09-21 09:55:45 -0700539 __le16 atime;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate);
Stephane Kardas62a36c42005-09-21 09:55:45 -0700541 fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542 raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 +
543 inode->i_ctime.tv_nsec / 10000000;
544 }
545 spin_unlock(&sbi->inode_hash_lock);
546 mark_buffer_dirty(bh);
547 if (wait)
548 err = sync_dirty_buffer(bh);
549 brelse(bh);
550out:
551 unlock_kernel();
552 return err;
553}
554
555int fat_sync_inode(struct inode *inode)
556{
557 return fat_write_inode(inode, 1);
558}
559
OGAWA Hirofumi7c709d02006-01-08 01:02:10 -0800560EXPORT_SYMBOL_GPL(fat_sync_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561
562static int fat_show_options(struct seq_file *m, struct vfsmount *mnt);
563static struct super_operations fat_sops = {
564 .alloc_inode = fat_alloc_inode,
565 .destroy_inode = fat_destroy_inode,
566 .write_inode = fat_write_inode,
567 .delete_inode = fat_delete_inode,
568 .put_super = fat_put_super,
OGAWA Hirofumia6bf6b22006-01-08 01:02:08 -0800569 .write_super = fat_write_super,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 .statfs = fat_statfs,
571 .clear_inode = fat_clear_inode,
572 .remount_fs = fat_remount,
573
574 .read_inode = make_bad_inode,
575
576 .show_options = fat_show_options,
577};
578
579/*
580 * a FAT file handle with fhtype 3 is
581 * 0/ i_ino - for fast, reliable lookup if still in the cache
582 * 1/ i_generation - to see if i_ino is still valid
583 * bit 0 == 0 iff directory
584 * 2/ i_pos(8-39) - if ino has changed, but still in cache
585 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
586 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
587 *
588 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
589 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
590 * of i_logstart is used to store the directory entry offset.
591 */
592
593static struct dentry *
594fat_decode_fh(struct super_block *sb, __u32 *fh, int len, int fhtype,
595 int (*acceptable)(void *context, struct dentry *de),
596 void *context)
597{
598 if (fhtype != 3)
599 return ERR_PTR(-ESTALE);
600 if (len < 5)
601 return ERR_PTR(-ESTALE);
602
603 return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable, context);
604}
605
606static struct dentry *fat_get_dentry(struct super_block *sb, void *inump)
607{
608 struct inode *inode = NULL;
609 struct dentry *result;
610 __u32 *fh = inump;
611
612 inode = iget(sb, fh[0]);
613 if (!inode || is_bad_inode(inode) || inode->i_generation != fh[1]) {
614 if (inode)
615 iput(inode);
616 inode = NULL;
617 }
618 if (!inode) {
619 loff_t i_pos;
620 int i_logstart = fh[3] & 0x0fffffff;
621
622 i_pos = (loff_t)fh[2] << 8;
623 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);
624
625 /* try 2 - see if i_pos is in F-d-c
626 * require i_logstart to be the same
627 * Will fail if you truncate and then re-write
628 */
629
630 inode = fat_iget(sb, i_pos);
631 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
632 iput(inode);
633 inode = NULL;
634 }
635 }
636 if (!inode) {
637 /* For now, do nothing
638 * What we could do is:
639 * follow the file starting at fh[4], and record
640 * the ".." entry, and the name of the fh[2] entry.
641 * The follow the ".." file finding the next step up.
642 * This way we build a path to the root of
643 * the tree. If this works, we lookup the path and so
644 * get this inode into the cache.
645 * Finally try the fat_iget lookup again
646 * If that fails, then weare totally out of luck
647 * But all that is for another day
648 */
649 }
650 if (!inode)
651 return ERR_PTR(-ESTALE);
652
653
654 /* now to find a dentry.
655 * If possible, get a well-connected one
656 */
657 result = d_alloc_anon(inode);
658 if (result == NULL) {
659 iput(inode);
660 return ERR_PTR(-ENOMEM);
661 }
662 result->d_op = sb->s_root->d_op;
663 return result;
664}
665
666static int
667fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
668{
669 int len = *lenp;
670 struct inode *inode = de->d_inode;
671 u32 ipos_h, ipos_m, ipos_l;
672
673 if (len < 5)
674 return 255; /* no room */
675
676 ipos_h = MSDOS_I(inode)->i_pos >> 8;
677 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
678 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28;
679 *lenp = 5;
680 fh[0] = inode->i_ino;
681 fh[1] = inode->i_generation;
682 fh[2] = ipos_h;
683 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart;
684 spin_lock(&de->d_lock);
685 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart;
686 spin_unlock(&de->d_lock);
687 return 3;
688}
689
690static struct dentry *fat_get_parent(struct dentry *child)
691{
692 struct buffer_head *bh;
693 struct msdos_dir_entry *de;
694 loff_t i_pos;
695 struct dentry *parent;
696 struct inode *inode;
697 int err;
698
699 lock_kernel();
700
701 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos);
702 if (err) {
703 parent = ERR_PTR(err);
704 goto out;
705 }
706 inode = fat_build_inode(child->d_sb, de, i_pos);
707 brelse(bh);
708 if (IS_ERR(inode)) {
709 parent = ERR_PTR(PTR_ERR(inode));
710 goto out;
711 }
712 parent = d_alloc_anon(inode);
713 if (!parent) {
714 iput(inode);
715 parent = ERR_PTR(-ENOMEM);
716 }
717out:
718 unlock_kernel();
719
720 return parent;
721}
722
723static struct export_operations fat_export_ops = {
724 .decode_fh = fat_decode_fh,
725 .encode_fh = fat_encode_fh,
726 .get_dentry = fat_get_dentry,
727 .get_parent = fat_get_parent,
728};
729
730static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
731{
732 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb);
733 struct fat_mount_options *opts = &sbi->options;
734 int isvfat = opts->isvfat;
735
736 if (opts->fs_uid != 0)
737 seq_printf(m, ",uid=%u", opts->fs_uid);
738 if (opts->fs_gid != 0)
739 seq_printf(m, ",gid=%u", opts->fs_gid);
740 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
741 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
742 if (sbi->nls_disk)
743 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset);
744 if (isvfat) {
745 if (sbi->nls_io)
746 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
747
748 switch (opts->shortname) {
749 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
750 seq_puts(m, ",shortname=win95");
751 break;
752 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
753 seq_puts(m, ",shortname=winnt");
754 break;
755 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
756 seq_puts(m, ",shortname=mixed");
757 break;
758 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
759 /* seq_puts(m, ",shortname=lower"); */
760 break;
761 default:
762 seq_puts(m, ",shortname=unknown");
763 break;
764 }
765 }
766 if (opts->name_check != 'n')
767 seq_printf(m, ",check=%c", opts->name_check);
768 if (opts->quiet)
769 seq_puts(m, ",quiet");
770 if (opts->showexec)
771 seq_puts(m, ",showexec");
772 if (opts->sys_immutable)
773 seq_puts(m, ",sys_immutable");
774 if (!isvfat) {
775 if (opts->dotsOK)
776 seq_puts(m, ",dotsOK=yes");
777 if (opts->nocase)
778 seq_puts(m, ",nocase");
779 } else {
780 if (opts->utf8)
781 seq_puts(m, ",utf8");
782 if (opts->unicode_xlate)
783 seq_puts(m, ",uni_xlate");
784 if (!opts->numtail)
785 seq_puts(m, ",nonumtail");
786 }
787
788 return 0;
789}
790
791enum {
792 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
793 Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, Opt_nocase,
794 Opt_quiet, Opt_showexec, Opt_debug, Opt_immutable,
795 Opt_dots, Opt_nodots,
796 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
797 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
798 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
799 Opt_obsolate, Opt_err,
800};
801
802static match_table_t fat_tokens = {
803 {Opt_check_r, "check=relaxed"},
804 {Opt_check_s, "check=strict"},
805 {Opt_check_n, "check=normal"},
806 {Opt_check_r, "check=r"},
807 {Opt_check_s, "check=s"},
808 {Opt_check_n, "check=n"},
809 {Opt_uid, "uid=%u"},
810 {Opt_gid, "gid=%u"},
811 {Opt_umask, "umask=%o"},
812 {Opt_dmask, "dmask=%o"},
813 {Opt_fmask, "fmask=%o"},
814 {Opt_codepage, "codepage=%u"},
815 {Opt_nocase, "nocase"},
816 {Opt_quiet, "quiet"},
817 {Opt_showexec, "showexec"},
818 {Opt_debug, "debug"},
819 {Opt_immutable, "sys_immutable"},
820 {Opt_obsolate, "conv=binary"},
821 {Opt_obsolate, "conv=text"},
822 {Opt_obsolate, "conv=auto"},
823 {Opt_obsolate, "conv=b"},
824 {Opt_obsolate, "conv=t"},
825 {Opt_obsolate, "conv=a"},
826 {Opt_obsolate, "fat=%u"},
827 {Opt_obsolate, "blocksize=%u"},
828 {Opt_obsolate, "cvf_format=%20s"},
829 {Opt_obsolate, "cvf_options=%100s"},
830 {Opt_obsolate, "posix"},
831 {Opt_err, NULL}
832};
833static match_table_t msdos_tokens = {
834 {Opt_nodots, "nodots"},
835 {Opt_nodots, "dotsOK=no"},
836 {Opt_dots, "dots"},
837 {Opt_dots, "dotsOK=yes"},
838 {Opt_err, NULL}
839};
840static match_table_t vfat_tokens = {
841 {Opt_charset, "iocharset=%s"},
842 {Opt_shortname_lower, "shortname=lower"},
843 {Opt_shortname_win95, "shortname=win95"},
844 {Opt_shortname_winnt, "shortname=winnt"},
845 {Opt_shortname_mixed, "shortname=mixed"},
846 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
847 {Opt_utf8_no, "utf8=no"},
848 {Opt_utf8_no, "utf8=false"},
849 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
850 {Opt_utf8_yes, "utf8=yes"},
851 {Opt_utf8_yes, "utf8=true"},
852 {Opt_utf8_yes, "utf8"},
853 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
854 {Opt_uni_xl_no, "uni_xlate=no"},
855 {Opt_uni_xl_no, "uni_xlate=false"},
856 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
857 {Opt_uni_xl_yes, "uni_xlate=yes"},
858 {Opt_uni_xl_yes, "uni_xlate=true"},
859 {Opt_uni_xl_yes, "uni_xlate"},
860 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
861 {Opt_nonumtail_no, "nonumtail=no"},
862 {Opt_nonumtail_no, "nonumtail=false"},
863 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
864 {Opt_nonumtail_yes, "nonumtail=yes"},
865 {Opt_nonumtail_yes, "nonumtail=true"},
866 {Opt_nonumtail_yes, "nonumtail"},
867 {Opt_err, NULL}
868};
869
Christoph Hellwig41a34a42005-11-08 21:34:57 -0800870static int parse_options(char *options, int is_vfat, int silent, int *debug,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871 struct fat_mount_options *opts)
872{
873 char *p;
874 substring_t args[MAX_OPT_ARGS];
875 int option;
876 char *iocharset;
877
878 opts->isvfat = is_vfat;
879
880 opts->fs_uid = current->uid;
881 opts->fs_gid = current->gid;
882 opts->fs_fmask = opts->fs_dmask = current->fs->umask;
883 opts->codepage = fat_default_codepage;
884 opts->iocharset = fat_default_iocharset;
885 if (is_vfat)
886 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95;
887 else
888 opts->shortname = 0;
889 opts->name_check = 'n';
890 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
891 opts->utf8 = opts->unicode_xlate = 0;
892 opts->numtail = 1;
893 opts->nocase = 0;
894 *debug = 0;
895
896 if (!options)
897 return 0;
898
899 while ((p = strsep(&options, ",")) != NULL) {
900 int token;
901 if (!*p)
902 continue;
903
904 token = match_token(p, fat_tokens, args);
905 if (token == Opt_err) {
906 if (is_vfat)
907 token = match_token(p, vfat_tokens, args);
908 else
909 token = match_token(p, msdos_tokens, args);
910 }
911 switch (token) {
912 case Opt_check_s:
913 opts->name_check = 's';
914 break;
915 case Opt_check_r:
916 opts->name_check = 'r';
917 break;
918 case Opt_check_n:
919 opts->name_check = 'n';
920 break;
921 case Opt_nocase:
922 if (!is_vfat)
923 opts->nocase = 1;
924 else {
925 /* for backward compatibility */
926 opts->shortname = VFAT_SFN_DISPLAY_WIN95
927 | VFAT_SFN_CREATE_WIN95;
928 }
929 break;
930 case Opt_quiet:
931 opts->quiet = 1;
932 break;
933 case Opt_showexec:
934 opts->showexec = 1;
935 break;
936 case Opt_debug:
937 *debug = 1;
938 break;
939 case Opt_immutable:
940 opts->sys_immutable = 1;
941 break;
942 case Opt_uid:
943 if (match_int(&args[0], &option))
944 return 0;
945 opts->fs_uid = option;
946 break;
947 case Opt_gid:
948 if (match_int(&args[0], &option))
949 return 0;
950 opts->fs_gid = option;
951 break;
952 case Opt_umask:
953 if (match_octal(&args[0], &option))
954 return 0;
955 opts->fs_fmask = opts->fs_dmask = option;
956 break;
957 case Opt_dmask:
958 if (match_octal(&args[0], &option))
959 return 0;
960 opts->fs_dmask = option;
961 break;
962 case Opt_fmask:
963 if (match_octal(&args[0], &option))
964 return 0;
965 opts->fs_fmask = option;
966 break;
967 case Opt_codepage:
968 if (match_int(&args[0], &option))
969 return 0;
970 opts->codepage = option;
971 break;
972
973 /* msdos specific */
974 case Opt_dots:
975 opts->dotsOK = 1;
976 break;
977 case Opt_nodots:
978 opts->dotsOK = 0;
979 break;
980
981 /* vfat specific */
982 case Opt_charset:
983 if (opts->iocharset != fat_default_iocharset)
984 kfree(opts->iocharset);
985 iocharset = match_strdup(&args[0]);
986 if (!iocharset)
987 return -ENOMEM;
988 opts->iocharset = iocharset;
989 break;
990 case Opt_shortname_lower:
991 opts->shortname = VFAT_SFN_DISPLAY_LOWER
992 | VFAT_SFN_CREATE_WIN95;
993 break;
994 case Opt_shortname_win95:
995 opts->shortname = VFAT_SFN_DISPLAY_WIN95
996 | VFAT_SFN_CREATE_WIN95;
997 break;
998 case Opt_shortname_winnt:
999 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1000 | VFAT_SFN_CREATE_WINNT;
1001 break;
1002 case Opt_shortname_mixed:
1003 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1004 | VFAT_SFN_CREATE_WIN95;
1005 break;
1006 case Opt_utf8_no: /* 0 or no or false */
1007 opts->utf8 = 0;
1008 break;
1009 case Opt_utf8_yes: /* empty or 1 or yes or true */
1010 opts->utf8 = 1;
1011 break;
1012 case Opt_uni_xl_no: /* 0 or no or false */
1013 opts->unicode_xlate = 0;
1014 break;
1015 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1016 opts->unicode_xlate = 1;
1017 break;
1018 case Opt_nonumtail_no: /* 0 or no or false */
1019 opts->numtail = 1; /* negated option */
1020 break;
1021 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1022 opts->numtail = 0; /* negated option */
1023 break;
1024
1025 /* obsolete mount options */
1026 case Opt_obsolate:
1027 printk(KERN_INFO "FAT: \"%s\" option is obsolete, "
1028 "not supported now\n", p);
1029 break;
1030 /* unknown option */
1031 default:
Christoph Hellwig41a34a42005-11-08 21:34:57 -08001032 if (!silent) {
1033 printk(KERN_ERR
1034 "FAT: Unrecognized mount option \"%s\" "
1035 "or missing value\n", p);
1036 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001037 return -EINVAL;
1038 }
1039 }
1040 /* UTF8 doesn't provide FAT semantics */
1041 if (!strcmp(opts->iocharset, "utf8")) {
1042 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset"
1043 " for FAT filesystems, filesystem will be case sensitive!\n");
1044 }
1045
1046 if (opts->unicode_xlate)
1047 opts->utf8 = 0;
1048
1049 return 0;
1050}
1051
1052static int fat_read_root(struct inode *inode)
1053{
1054 struct super_block *sb = inode->i_sb;
1055 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1056 int error;
1057
1058 MSDOS_I(inode)->i_pos = 0;
1059 inode->i_uid = sbi->options.fs_uid;
1060 inode->i_gid = sbi->options.fs_gid;
1061 inode->i_version++;
1062 inode->i_generation = 0;
1063 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR;
1064 inode->i_op = sbi->dir_ops;
1065 inode->i_fop = &fat_dir_operations;
1066 if (sbi->fat_bits == 32) {
1067 MSDOS_I(inode)->i_start = sbi->root_cluster;
1068 error = fat_calc_dir_size(inode);
1069 if (error < 0)
1070 return error;
1071 } else {
1072 MSDOS_I(inode)->i_start = 0;
1073 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1074 }
1075 inode->i_blksize = sbi->cluster_size;
1076 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1077 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1078 MSDOS_I(inode)->i_logstart = 0;
1079 MSDOS_I(inode)->mmu_private = inode->i_size;
1080
1081 MSDOS_I(inode)->i_attrs = ATTR_NONE;
1082 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1083 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1084 inode->i_nlink = fat_subdirs(inode)+2;
1085
1086 return 0;
1087}
1088
1089/*
1090 * Read the super block of an MS-DOS FS.
1091 */
1092int fat_fill_super(struct super_block *sb, void *data, int silent,
1093 struct inode_operations *fs_dir_inode_ops, int isvfat)
1094{
1095 struct inode *root_inode = NULL;
1096 struct buffer_head *bh;
1097 struct fat_boot_sector *b;
1098 struct msdos_sb_info *sbi;
1099 u16 logical_sector_size;
1100 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1101 int debug;
1102 unsigned int media;
1103 long error;
1104 char buf[50];
1105
1106 sbi = kmalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1107 if (!sbi)
1108 return -ENOMEM;
1109 sb->s_fs_info = sbi;
1110 memset(sbi, 0, sizeof(struct msdos_sb_info));
1111
1112 sb->s_flags |= MS_NODIRATIME;
1113 sb->s_magic = MSDOS_SUPER_MAGIC;
1114 sb->s_op = &fat_sops;
1115 sb->s_export_op = &fat_export_ops;
1116 sbi->dir_ops = fs_dir_inode_ops;
1117
Christoph Hellwig41a34a42005-11-08 21:34:57 -08001118 error = parse_options(data, isvfat, silent, &debug, &sbi->options);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119 if (error)
1120 goto out_fail;
1121
1122 error = -EIO;
1123 sb_min_blocksize(sb, 512);
1124 bh = sb_bread(sb, 0);
1125 if (bh == NULL) {
1126 printk(KERN_ERR "FAT: unable to read boot sector\n");
1127 goto out_fail;
1128 }
1129
1130 b = (struct fat_boot_sector *) bh->b_data;
1131 if (!b->reserved) {
1132 if (!silent)
1133 printk(KERN_ERR "FAT: bogus number of reserved sectors\n");
1134 brelse(bh);
1135 goto out_invalid;
1136 }
1137 if (!b->fats) {
1138 if (!silent)
1139 printk(KERN_ERR "FAT: bogus number of FAT structure\n");
1140 brelse(bh);
1141 goto out_invalid;
1142 }
1143
1144 /*
1145 * Earlier we checked here that b->secs_track and b->head are nonzero,
1146 * but it turns out valid FAT filesystems can have zero there.
1147 */
1148
1149 media = b->media;
1150 if (!FAT_VALID_MEDIA(media)) {
1151 if (!silent)
1152 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n",
1153 media);
1154 brelse(bh);
1155 goto out_invalid;
1156 }
1157 logical_sector_size =
1158 le16_to_cpu(get_unaligned((__le16 *)&b->sector_size));
1159 if (!logical_sector_size
1160 || (logical_sector_size & (logical_sector_size - 1))
1161 || (logical_sector_size < 512)
1162 || (PAGE_CACHE_SIZE < logical_sector_size)) {
1163 if (!silent)
1164 printk(KERN_ERR "FAT: bogus logical sector size %u\n",
1165 logical_sector_size);
1166 brelse(bh);
1167 goto out_invalid;
1168 }
1169 sbi->sec_per_clus = b->sec_per_clus;
1170 if (!sbi->sec_per_clus
1171 || (sbi->sec_per_clus & (sbi->sec_per_clus - 1))) {
1172 if (!silent)
1173 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
1174 sbi->sec_per_clus);
1175 brelse(bh);
1176 goto out_invalid;
1177 }
1178
1179 if (logical_sector_size < sb->s_blocksize) {
1180 printk(KERN_ERR "FAT: logical sector size too small for device"
1181 " (logical sector size = %u)\n", logical_sector_size);
1182 brelse(bh);
1183 goto out_fail;
1184 }
1185 if (logical_sector_size > sb->s_blocksize) {
1186 brelse(bh);
1187
1188 if (!sb_set_blocksize(sb, logical_sector_size)) {
1189 printk(KERN_ERR "FAT: unable to set blocksize %u\n",
1190 logical_sector_size);
1191 goto out_fail;
1192 }
1193 bh = sb_bread(sb, 0);
1194 if (bh == NULL) {
1195 printk(KERN_ERR "FAT: unable to read boot sector"
1196 " (logical sector size = %lu)\n",
1197 sb->s_blocksize);
1198 goto out_fail;
1199 }
1200 b = (struct fat_boot_sector *) bh->b_data;
1201 }
1202
1203 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1204 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1205 sbi->fats = b->fats;
1206 sbi->fat_bits = 0; /* Don't know yet */
1207 sbi->fat_start = le16_to_cpu(b->reserved);
1208 sbi->fat_length = le16_to_cpu(b->fat_length);
1209 sbi->root_cluster = 0;
1210 sbi->free_clusters = -1; /* Don't know yet */
1211 sbi->prev_free = FAT_START_ENT;
1212
1213 if (!sbi->fat_length && b->fat32_length) {
1214 struct fat_boot_fsinfo *fsinfo;
1215 struct buffer_head *fsinfo_bh;
1216
1217 /* Must be FAT32 */
1218 sbi->fat_bits = 32;
1219 sbi->fat_length = le32_to_cpu(b->fat32_length);
1220 sbi->root_cluster = le32_to_cpu(b->root_cluster);
1221
1222 sb->s_maxbytes = 0xffffffff;
1223
1224 /* MC - if info_sector is 0, don't multiply by 0 */
1225 sbi->fsinfo_sector = le16_to_cpu(b->info_sector);
1226 if (sbi->fsinfo_sector == 0)
1227 sbi->fsinfo_sector = 1;
1228
1229 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1230 if (fsinfo_bh == NULL) {
1231 printk(KERN_ERR "FAT: bread failed, FSINFO block"
1232 " (sector = %lu)\n", sbi->fsinfo_sector);
1233 brelse(bh);
1234 goto out_fail;
1235 }
1236
1237 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1238 if (!IS_FSINFO(fsinfo)) {
1239 printk(KERN_WARNING
1240 "FAT: Did not find valid FSINFO signature.\n"
1241 " Found signature1 0x%08x signature2 0x%08x"
1242 " (sector = %lu)\n",
1243 le32_to_cpu(fsinfo->signature1),
1244 le32_to_cpu(fsinfo->signature2),
1245 sbi->fsinfo_sector);
1246 } else {
1247 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1248 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1249 }
1250
1251 brelse(fsinfo_bh);
1252 }
1253
1254 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1255 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1256
1257 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1258 sbi->dir_entries =
1259 le16_to_cpu(get_unaligned((__le16 *)&b->dir_entries));
1260 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1261 if (!silent)
1262 printk(KERN_ERR "FAT: bogus directroy-entries per block"
1263 " (%u)\n", sbi->dir_entries);
1264 brelse(bh);
1265 goto out_invalid;
1266 }
1267
1268 rootdir_sectors = sbi->dir_entries
1269 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1270 sbi->data_start = sbi->dir_start + rootdir_sectors;
1271 total_sectors = le16_to_cpu(get_unaligned((__le16 *)&b->sectors));
1272 if (total_sectors == 0)
1273 total_sectors = le32_to_cpu(b->total_sect);
1274
1275 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1276
1277 if (sbi->fat_bits != 32)
1278 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1279
1280 /* check that FAT table does not overflow */
1281 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1282 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1283 if (total_clusters > MAX_FAT(sb)) {
1284 if (!silent)
1285 printk(KERN_ERR "FAT: count of clusters too big (%u)\n",
1286 total_clusters);
1287 brelse(bh);
1288 goto out_invalid;
1289 }
1290
1291 sbi->max_cluster = total_clusters + FAT_START_ENT;
1292 /* check the free_clusters, it's not necessarily correct */
1293 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1294 sbi->free_clusters = -1;
1295 /* check the prev_free, it's not necessarily correct */
1296 sbi->prev_free %= sbi->max_cluster;
1297 if (sbi->prev_free < FAT_START_ENT)
1298 sbi->prev_free = FAT_START_ENT;
1299
1300 brelse(bh);
1301
1302 /* set up enough so that it can read an inode */
1303 fat_hash_init(sb);
1304 fat_ent_access_init(sb);
1305
1306 /*
1307 * The low byte of FAT's first entry must have same value with
1308 * media-field. But in real world, too many devices is
1309 * writing wrong value. So, removed that validity check.
1310 *
1311 * if (FAT_FIRST_ENT(sb, media) != first)
1312 */
1313
1314 error = -EINVAL;
1315 sprintf(buf, "cp%d", sbi->options.codepage);
1316 sbi->nls_disk = load_nls(buf);
1317 if (!sbi->nls_disk) {
1318 printk(KERN_ERR "FAT: codepage %s not found\n", buf);
1319 goto out_fail;
1320 }
1321
1322 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1323 if (sbi->options.isvfat) {
1324 sbi->nls_io = load_nls(sbi->options.iocharset);
1325 if (!sbi->nls_io) {
1326 printk(KERN_ERR "FAT: IO charset %s not found\n",
1327 sbi->options.iocharset);
1328 goto out_fail;
1329 }
1330 }
1331
1332 error = -ENOMEM;
1333 root_inode = new_inode(sb);
1334 if (!root_inode)
1335 goto out_fail;
1336 root_inode->i_ino = MSDOS_ROOT_INO;
1337 root_inode->i_version = 1;
1338 error = fat_read_root(root_inode);
1339 if (error < 0)
1340 goto out_fail;
1341 error = -ENOMEM;
1342 insert_inode_hash(root_inode);
1343 sb->s_root = d_alloc_root(root_inode);
1344 if (!sb->s_root) {
1345 printk(KERN_ERR "FAT: get root inode failed\n");
1346 goto out_fail;
1347 }
1348
1349 return 0;
1350
1351out_invalid:
1352 error = -EINVAL;
1353 if (!silent)
1354 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem"
1355 " on dev %s.\n", sb->s_id);
1356
1357out_fail:
1358 if (root_inode)
1359 iput(root_inode);
1360 if (sbi->nls_io)
1361 unload_nls(sbi->nls_io);
1362 if (sbi->nls_disk)
1363 unload_nls(sbi->nls_disk);
1364 if (sbi->options.iocharset != fat_default_iocharset)
1365 kfree(sbi->options.iocharset);
1366 sb->s_fs_info = NULL;
1367 kfree(sbi);
1368 return error;
1369}
1370
OGAWA Hirofumi7c709d02006-01-08 01:02:10 -08001371EXPORT_SYMBOL_GPL(fat_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372
1373int __init fat_cache_init(void);
Andrew Mortonef6689e2005-06-30 22:13:14 -07001374void fat_cache_destroy(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001375
1376static int __init init_fat_fs(void)
1377{
Pekka J Enberg532a39a2005-06-30 02:59:01 -07001378 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001379
Pekka J Enberg532a39a2005-06-30 02:59:01 -07001380 err = fat_cache_init();
1381 if (err)
1382 return err;
1383
1384 err = fat_init_inodecache();
1385 if (err)
1386 goto failed;
1387
1388 return 0;
1389
1390failed:
1391 fat_cache_destroy();
1392 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001393}
1394
1395static void __exit exit_fat_fs(void)
1396{
1397 fat_cache_destroy();
1398 fat_destroy_inodecache();
1399}
1400
1401module_init(init_fat_fs)
1402module_exit(exit_fat_fs)
1403
1404MODULE_LICENSE("GPL");