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Merge branch 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata
[deliverable/linux.git] / 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/module.h>
14 #include <linux/init.h>
15 #include <linux/time.h>
16 #include <linux/slab.h>
17 #include <linux/seq_file.h>
18 #include <linux/pagemap.h>
19 #include <linux/mpage.h>
20 #include <linux/buffer_head.h>
21 #include <linux/mount.h>
22 #include <linux/aio.h>
23 #include <linux/vfs.h>
24 #include <linux/parser.h>
25 #include <linux/uio.h>
26 #include <linux/writeback.h>
27 #include <linux/log2.h>
28 #include <linux/hash.h>
29 #include <linux/blkdev.h>
30 #include <asm/unaligned.h>
31 #include "fat.h"
32
33 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
34 /* if user don't select VFAT, this is undefined. */
35 #define CONFIG_FAT_DEFAULT_IOCHARSET ""
36 #endif
37
38 #define KB_IN_SECTORS 2
39
40 /*
41 * A deserialized copy of the on-disk structure laid out in struct
42 * fat_boot_sector.
43 */
44 struct fat_bios_param_block {
45 u16 fat_sector_size;
46 u8 fat_sec_per_clus;
47 u16 fat_reserved;
48 u8 fat_fats;
49 u16 fat_dir_entries;
50 u16 fat_sectors;
51 u16 fat_fat_length;
52 u32 fat_total_sect;
53
54 u8 fat16_state;
55 u32 fat16_vol_id;
56
57 u32 fat32_length;
58 u32 fat32_root_cluster;
59 u16 fat32_info_sector;
60 u8 fat32_state;
61 u32 fat32_vol_id;
62 };
63
64 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
65 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
66
67 static struct fat_floppy_defaults {
68 unsigned nr_sectors;
69 unsigned sec_per_clus;
70 unsigned dir_entries;
71 unsigned media;
72 unsigned fat_length;
73 } floppy_defaults[] = {
74 {
75 .nr_sectors = 160 * KB_IN_SECTORS,
76 .sec_per_clus = 1,
77 .dir_entries = 64,
78 .media = 0xFE,
79 .fat_length = 1,
80 },
81 {
82 .nr_sectors = 180 * KB_IN_SECTORS,
83 .sec_per_clus = 1,
84 .dir_entries = 64,
85 .media = 0xFC,
86 .fat_length = 2,
87 },
88 {
89 .nr_sectors = 320 * KB_IN_SECTORS,
90 .sec_per_clus = 2,
91 .dir_entries = 112,
92 .media = 0xFF,
93 .fat_length = 1,
94 },
95 {
96 .nr_sectors = 360 * KB_IN_SECTORS,
97 .sec_per_clus = 2,
98 .dir_entries = 112,
99 .media = 0xFD,
100 .fat_length = 2,
101 },
102 };
103
104 static int fat_add_cluster(struct inode *inode)
105 {
106 int err, cluster;
107
108 err = fat_alloc_clusters(inode, &cluster, 1);
109 if (err)
110 return err;
111 /* FIXME: this cluster should be added after data of this
112 * cluster is writed */
113 err = fat_chain_add(inode, cluster, 1);
114 if (err)
115 fat_free_clusters(inode, cluster);
116 return err;
117 }
118
119 static inline int __fat_get_block(struct inode *inode, sector_t iblock,
120 unsigned long *max_blocks,
121 struct buffer_head *bh_result, int create)
122 {
123 struct super_block *sb = inode->i_sb;
124 struct msdos_sb_info *sbi = MSDOS_SB(sb);
125 unsigned long mapped_blocks;
126 sector_t phys;
127 int err, offset;
128
129 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
130 if (err)
131 return err;
132 if (phys) {
133 map_bh(bh_result, sb, phys);
134 *max_blocks = min(mapped_blocks, *max_blocks);
135 return 0;
136 }
137 if (!create)
138 return 0;
139
140 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
141 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
142 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
143 return -EIO;
144 }
145
146 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
147 if (!offset) {
148 /* TODO: multiple cluster allocation would be desirable. */
149 err = fat_add_cluster(inode);
150 if (err)
151 return err;
152 }
153 /* available blocks on this cluster */
154 mapped_blocks = sbi->sec_per_clus - offset;
155
156 *max_blocks = min(mapped_blocks, *max_blocks);
157 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
158
159 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
160 if (err)
161 return err;
162
163 BUG_ON(!phys);
164 BUG_ON(*max_blocks != mapped_blocks);
165 set_buffer_new(bh_result);
166 map_bh(bh_result, sb, phys);
167
168 return 0;
169 }
170
171 static int fat_get_block(struct inode *inode, sector_t iblock,
172 struct buffer_head *bh_result, int create)
173 {
174 struct super_block *sb = inode->i_sb;
175 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
176 int err;
177
178 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
179 if (err)
180 return err;
181 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
182 return 0;
183 }
184
185 static int fat_writepage(struct page *page, struct writeback_control *wbc)
186 {
187 return block_write_full_page(page, fat_get_block, wbc);
188 }
189
190 static int fat_writepages(struct address_space *mapping,
191 struct writeback_control *wbc)
192 {
193 return mpage_writepages(mapping, wbc, fat_get_block);
194 }
195
196 static int fat_readpage(struct file *file, struct page *page)
197 {
198 return mpage_readpage(page, fat_get_block);
199 }
200
201 static int fat_readpages(struct file *file, struct address_space *mapping,
202 struct list_head *pages, unsigned nr_pages)
203 {
204 return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
205 }
206
207 static void fat_write_failed(struct address_space *mapping, loff_t to)
208 {
209 struct inode *inode = mapping->host;
210
211 if (to > inode->i_size) {
212 truncate_pagecache(inode, inode->i_size);
213 fat_truncate_blocks(inode, inode->i_size);
214 }
215 }
216
217 static int fat_write_begin(struct file *file, struct address_space *mapping,
218 loff_t pos, unsigned len, unsigned flags,
219 struct page **pagep, void **fsdata)
220 {
221 int err;
222
223 *pagep = NULL;
224 err = cont_write_begin(file, mapping, pos, len, flags,
225 pagep, fsdata, fat_get_block,
226 &MSDOS_I(mapping->host)->mmu_private);
227 if (err < 0)
228 fat_write_failed(mapping, pos + len);
229 return err;
230 }
231
232 static int fat_write_end(struct file *file, struct address_space *mapping,
233 loff_t pos, unsigned len, unsigned copied,
234 struct page *pagep, void *fsdata)
235 {
236 struct inode *inode = mapping->host;
237 int err;
238 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
239 if (err < len)
240 fat_write_failed(mapping, pos + len);
241 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
242 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
243 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
244 mark_inode_dirty(inode);
245 }
246 return err;
247 }
248
249 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
250 struct iov_iter *iter,
251 loff_t offset)
252 {
253 struct file *file = iocb->ki_filp;
254 struct address_space *mapping = file->f_mapping;
255 struct inode *inode = mapping->host;
256 size_t count = iov_iter_count(iter);
257 ssize_t ret;
258
259 if (rw == WRITE) {
260 /*
261 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
262 * so we need to update the ->mmu_private to block boundary.
263 *
264 * But we must fill the remaining area or hole by nul for
265 * updating ->mmu_private.
266 *
267 * Return 0, and fallback to normal buffered write.
268 */
269 loff_t size = offset + count;
270 if (MSDOS_I(inode)->mmu_private < size)
271 return 0;
272 }
273
274 /*
275 * FAT need to use the DIO_LOCKING for avoiding the race
276 * condition of fat_get_block() and ->truncate().
277 */
278 ret = blockdev_direct_IO(rw, iocb, inode, iter, offset, fat_get_block);
279 if (ret < 0 && (rw & WRITE))
280 fat_write_failed(mapping, offset + count);
281
282 return ret;
283 }
284
285 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
286 {
287 sector_t blocknr;
288
289 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
290 down_read(&MSDOS_I(mapping->host)->truncate_lock);
291 blocknr = generic_block_bmap(mapping, block, fat_get_block);
292 up_read(&MSDOS_I(mapping->host)->truncate_lock);
293
294 return blocknr;
295 }
296
297 static const struct address_space_operations fat_aops = {
298 .readpage = fat_readpage,
299 .readpages = fat_readpages,
300 .writepage = fat_writepage,
301 .writepages = fat_writepages,
302 .write_begin = fat_write_begin,
303 .write_end = fat_write_end,
304 .direct_IO = fat_direct_IO,
305 .bmap = _fat_bmap
306 };
307
308 /*
309 * New FAT inode stuff. We do the following:
310 * a) i_ino is constant and has nothing with on-disk location.
311 * b) FAT manages its own cache of directory entries.
312 * c) *This* cache is indexed by on-disk location.
313 * d) inode has an associated directory entry, all right, but
314 * it may be unhashed.
315 * e) currently entries are stored within struct inode. That should
316 * change.
317 * f) we deal with races in the following way:
318 * 1. readdir() and lookup() do FAT-dir-cache lookup.
319 * 2. rename() unhashes the F-d-c entry and rehashes it in
320 * a new place.
321 * 3. unlink() and rmdir() unhash F-d-c entry.
322 * 4. fat_write_inode() checks whether the thing is unhashed.
323 * If it is we silently return. If it isn't we do bread(),
324 * check if the location is still valid and retry if it
325 * isn't. Otherwise we do changes.
326 * 5. Spinlock is used to protect hash/unhash/location check/lookup
327 * 6. fat_evict_inode() unhashes the F-d-c entry.
328 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
329 * and consider negative result as cache miss.
330 */
331
332 static void fat_hash_init(struct super_block *sb)
333 {
334 struct msdos_sb_info *sbi = MSDOS_SB(sb);
335 int i;
336
337 spin_lock_init(&sbi->inode_hash_lock);
338 for (i = 0; i < FAT_HASH_SIZE; i++)
339 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
340 }
341
342 static inline unsigned long fat_hash(loff_t i_pos)
343 {
344 return hash_32(i_pos, FAT_HASH_BITS);
345 }
346
347 static void dir_hash_init(struct super_block *sb)
348 {
349 struct msdos_sb_info *sbi = MSDOS_SB(sb);
350 int i;
351
352 spin_lock_init(&sbi->dir_hash_lock);
353 for (i = 0; i < FAT_HASH_SIZE; i++)
354 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
355 }
356
357 void fat_attach(struct inode *inode, loff_t i_pos)
358 {
359 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
360
361 if (inode->i_ino != MSDOS_ROOT_INO) {
362 struct hlist_head *head = sbi->inode_hashtable
363 + fat_hash(i_pos);
364
365 spin_lock(&sbi->inode_hash_lock);
366 MSDOS_I(inode)->i_pos = i_pos;
367 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
368 spin_unlock(&sbi->inode_hash_lock);
369 }
370
371 /* If NFS support is enabled, cache the mapping of start cluster
372 * to directory inode. This is used during reconnection of
373 * dentries to the filesystem root.
374 */
375 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
376 struct hlist_head *d_head = sbi->dir_hashtable;
377 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
378
379 spin_lock(&sbi->dir_hash_lock);
380 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
381 spin_unlock(&sbi->dir_hash_lock);
382 }
383 }
384 EXPORT_SYMBOL_GPL(fat_attach);
385
386 void fat_detach(struct inode *inode)
387 {
388 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
389 spin_lock(&sbi->inode_hash_lock);
390 MSDOS_I(inode)->i_pos = 0;
391 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
392 spin_unlock(&sbi->inode_hash_lock);
393
394 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
395 spin_lock(&sbi->dir_hash_lock);
396 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
397 spin_unlock(&sbi->dir_hash_lock);
398 }
399 }
400 EXPORT_SYMBOL_GPL(fat_detach);
401
402 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
403 {
404 struct msdos_sb_info *sbi = MSDOS_SB(sb);
405 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
406 struct msdos_inode_info *i;
407 struct inode *inode = NULL;
408
409 spin_lock(&sbi->inode_hash_lock);
410 hlist_for_each_entry(i, head, i_fat_hash) {
411 BUG_ON(i->vfs_inode.i_sb != sb);
412 if (i->i_pos != i_pos)
413 continue;
414 inode = igrab(&i->vfs_inode);
415 if (inode)
416 break;
417 }
418 spin_unlock(&sbi->inode_hash_lock);
419 return inode;
420 }
421
422 static int is_exec(unsigned char *extension)
423 {
424 unsigned char exe_extensions[] = "EXECOMBAT", *walk;
425
426 for (walk = exe_extensions; *walk; walk += 3)
427 if (!strncmp(extension, walk, 3))
428 return 1;
429 return 0;
430 }
431
432 static int fat_calc_dir_size(struct inode *inode)
433 {
434 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
435 int ret, fclus, dclus;
436
437 inode->i_size = 0;
438 if (MSDOS_I(inode)->i_start == 0)
439 return 0;
440
441 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
442 if (ret < 0)
443 return ret;
444 inode->i_size = (fclus + 1) << sbi->cluster_bits;
445
446 return 0;
447 }
448
449 /* doesn't deal with root inode */
450 int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
451 {
452 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
453 int error;
454
455 MSDOS_I(inode)->i_pos = 0;
456 inode->i_uid = sbi->options.fs_uid;
457 inode->i_gid = sbi->options.fs_gid;
458 inode->i_version++;
459 inode->i_generation = get_seconds();
460
461 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
462 inode->i_generation &= ~1;
463 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
464 inode->i_op = sbi->dir_ops;
465 inode->i_fop = &fat_dir_operations;
466
467 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
468 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
469 error = fat_calc_dir_size(inode);
470 if (error < 0)
471 return error;
472 MSDOS_I(inode)->mmu_private = inode->i_size;
473
474 set_nlink(inode, fat_subdirs(inode));
475 } else { /* not a directory */
476 inode->i_generation |= 1;
477 inode->i_mode = fat_make_mode(sbi, de->attr,
478 ((sbi->options.showexec && !is_exec(de->name + 8))
479 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
480 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
481
482 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
483 inode->i_size = le32_to_cpu(de->size);
484 inode->i_op = &fat_file_inode_operations;
485 inode->i_fop = &fat_file_operations;
486 inode->i_mapping->a_ops = &fat_aops;
487 MSDOS_I(inode)->mmu_private = inode->i_size;
488 }
489 if (de->attr & ATTR_SYS) {
490 if (sbi->options.sys_immutable)
491 inode->i_flags |= S_IMMUTABLE;
492 }
493 fat_save_attrs(inode, de->attr);
494
495 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
496 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
497
498 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
499 if (sbi->options.isvfat) {
500 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
501 de->cdate, de->ctime_cs);
502 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
503 } else
504 inode->i_ctime = inode->i_atime = inode->i_mtime;
505
506 return 0;
507 }
508
509 static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
510 {
511 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
512 mutex_lock(&sbi->nfs_build_inode_lock);
513 }
514
515 static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
516 {
517 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
518 mutex_unlock(&sbi->nfs_build_inode_lock);
519 }
520
521 struct inode *fat_build_inode(struct super_block *sb,
522 struct msdos_dir_entry *de, loff_t i_pos)
523 {
524 struct inode *inode;
525 int err;
526
527 fat_lock_build_inode(MSDOS_SB(sb));
528 inode = fat_iget(sb, i_pos);
529 if (inode)
530 goto out;
531 inode = new_inode(sb);
532 if (!inode) {
533 inode = ERR_PTR(-ENOMEM);
534 goto out;
535 }
536 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
537 inode->i_version = 1;
538 err = fat_fill_inode(inode, de);
539 if (err) {
540 iput(inode);
541 inode = ERR_PTR(err);
542 goto out;
543 }
544 fat_attach(inode, i_pos);
545 insert_inode_hash(inode);
546 out:
547 fat_unlock_build_inode(MSDOS_SB(sb));
548 return inode;
549 }
550
551 EXPORT_SYMBOL_GPL(fat_build_inode);
552
553 static void fat_evict_inode(struct inode *inode)
554 {
555 truncate_inode_pages_final(&inode->i_data);
556 if (!inode->i_nlink) {
557 inode->i_size = 0;
558 fat_truncate_blocks(inode, 0);
559 }
560 invalidate_inode_buffers(inode);
561 clear_inode(inode);
562 fat_cache_inval_inode(inode);
563 fat_detach(inode);
564 }
565
566 static void fat_set_state(struct super_block *sb,
567 unsigned int set, unsigned int force)
568 {
569 struct buffer_head *bh;
570 struct fat_boot_sector *b;
571 struct msdos_sb_info *sbi = sb->s_fs_info;
572
573 /* do not change any thing if mounted read only */
574 if ((sb->s_flags & MS_RDONLY) && !force)
575 return;
576
577 /* do not change state if fs was dirty */
578 if (sbi->dirty) {
579 /* warn only on set (mount). */
580 if (set)
581 fat_msg(sb, KERN_WARNING, "Volume was not properly "
582 "unmounted. Some data may be corrupt. "
583 "Please run fsck.");
584 return;
585 }
586
587 bh = sb_bread(sb, 0);
588 if (bh == NULL) {
589 fat_msg(sb, KERN_ERR, "unable to read boot sector "
590 "to mark fs as dirty");
591 return;
592 }
593
594 b = (struct fat_boot_sector *) bh->b_data;
595
596 if (sbi->fat_bits == 32) {
597 if (set)
598 b->fat32.state |= FAT_STATE_DIRTY;
599 else
600 b->fat32.state &= ~FAT_STATE_DIRTY;
601 } else /* fat 16 and 12 */ {
602 if (set)
603 b->fat16.state |= FAT_STATE_DIRTY;
604 else
605 b->fat16.state &= ~FAT_STATE_DIRTY;
606 }
607
608 mark_buffer_dirty(bh);
609 sync_dirty_buffer(bh);
610 brelse(bh);
611 }
612
613 static void delayed_free(struct rcu_head *p)
614 {
615 struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
616 unload_nls(sbi->nls_disk);
617 unload_nls(sbi->nls_io);
618 if (sbi->options.iocharset != fat_default_iocharset)
619 kfree(sbi->options.iocharset);
620 kfree(sbi);
621 }
622
623 static void fat_put_super(struct super_block *sb)
624 {
625 struct msdos_sb_info *sbi = MSDOS_SB(sb);
626
627 fat_set_state(sb, 0, 0);
628
629 iput(sbi->fsinfo_inode);
630 iput(sbi->fat_inode);
631
632 call_rcu(&sbi->rcu, delayed_free);
633 }
634
635 static struct kmem_cache *fat_inode_cachep;
636
637 static struct inode *fat_alloc_inode(struct super_block *sb)
638 {
639 struct msdos_inode_info *ei;
640 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
641 if (!ei)
642 return NULL;
643
644 init_rwsem(&ei->truncate_lock);
645 return &ei->vfs_inode;
646 }
647
648 static void fat_i_callback(struct rcu_head *head)
649 {
650 struct inode *inode = container_of(head, struct inode, i_rcu);
651 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
652 }
653
654 static void fat_destroy_inode(struct inode *inode)
655 {
656 call_rcu(&inode->i_rcu, fat_i_callback);
657 }
658
659 static void init_once(void *foo)
660 {
661 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
662
663 spin_lock_init(&ei->cache_lru_lock);
664 ei->nr_caches = 0;
665 ei->cache_valid_id = FAT_CACHE_VALID + 1;
666 INIT_LIST_HEAD(&ei->cache_lru);
667 INIT_HLIST_NODE(&ei->i_fat_hash);
668 INIT_HLIST_NODE(&ei->i_dir_hash);
669 inode_init_once(&ei->vfs_inode);
670 }
671
672 static int __init fat_init_inodecache(void)
673 {
674 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
675 sizeof(struct msdos_inode_info),
676 0, (SLAB_RECLAIM_ACCOUNT|
677 SLAB_MEM_SPREAD),
678 init_once);
679 if (fat_inode_cachep == NULL)
680 return -ENOMEM;
681 return 0;
682 }
683
684 static void __exit fat_destroy_inodecache(void)
685 {
686 /*
687 * Make sure all delayed rcu free inodes are flushed before we
688 * destroy cache.
689 */
690 rcu_barrier();
691 kmem_cache_destroy(fat_inode_cachep);
692 }
693
694 static int fat_remount(struct super_block *sb, int *flags, char *data)
695 {
696 int new_rdonly;
697 struct msdos_sb_info *sbi = MSDOS_SB(sb);
698 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
699
700 sync_filesystem(sb);
701
702 /* make sure we update state on remount. */
703 new_rdonly = *flags & MS_RDONLY;
704 if (new_rdonly != (sb->s_flags & MS_RDONLY)) {
705 if (new_rdonly)
706 fat_set_state(sb, 0, 0);
707 else
708 fat_set_state(sb, 1, 1);
709 }
710 return 0;
711 }
712
713 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
714 {
715 struct super_block *sb = dentry->d_sb;
716 struct msdos_sb_info *sbi = MSDOS_SB(sb);
717 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
718
719 /* If the count of free cluster is still unknown, counts it here. */
720 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
721 int err = fat_count_free_clusters(dentry->d_sb);
722 if (err)
723 return err;
724 }
725
726 buf->f_type = dentry->d_sb->s_magic;
727 buf->f_bsize = sbi->cluster_size;
728 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
729 buf->f_bfree = sbi->free_clusters;
730 buf->f_bavail = sbi->free_clusters;
731 buf->f_fsid.val[0] = (u32)id;
732 buf->f_fsid.val[1] = (u32)(id >> 32);
733 buf->f_namelen =
734 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
735
736 return 0;
737 }
738
739 static int __fat_write_inode(struct inode *inode, int wait)
740 {
741 struct super_block *sb = inode->i_sb;
742 struct msdos_sb_info *sbi = MSDOS_SB(sb);
743 struct buffer_head *bh;
744 struct msdos_dir_entry *raw_entry;
745 loff_t i_pos;
746 sector_t blocknr;
747 int err, offset;
748
749 if (inode->i_ino == MSDOS_ROOT_INO)
750 return 0;
751
752 retry:
753 i_pos = fat_i_pos_read(sbi, inode);
754 if (!i_pos)
755 return 0;
756
757 fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
758 bh = sb_bread(sb, blocknr);
759 if (!bh) {
760 fat_msg(sb, KERN_ERR, "unable to read inode block "
761 "for updating (i_pos %lld)", i_pos);
762 return -EIO;
763 }
764 spin_lock(&sbi->inode_hash_lock);
765 if (i_pos != MSDOS_I(inode)->i_pos) {
766 spin_unlock(&sbi->inode_hash_lock);
767 brelse(bh);
768 goto retry;
769 }
770
771 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
772 if (S_ISDIR(inode->i_mode))
773 raw_entry->size = 0;
774 else
775 raw_entry->size = cpu_to_le32(inode->i_size);
776 raw_entry->attr = fat_make_attrs(inode);
777 fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
778 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
779 &raw_entry->date, NULL);
780 if (sbi->options.isvfat) {
781 __le16 atime;
782 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
783 &raw_entry->cdate, &raw_entry->ctime_cs);
784 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
785 &raw_entry->adate, NULL);
786 }
787 spin_unlock(&sbi->inode_hash_lock);
788 mark_buffer_dirty(bh);
789 err = 0;
790 if (wait)
791 err = sync_dirty_buffer(bh);
792 brelse(bh);
793 return err;
794 }
795
796 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
797 {
798 int err;
799
800 if (inode->i_ino == MSDOS_FSINFO_INO) {
801 struct super_block *sb = inode->i_sb;
802
803 mutex_lock(&MSDOS_SB(sb)->s_lock);
804 err = fat_clusters_flush(sb);
805 mutex_unlock(&MSDOS_SB(sb)->s_lock);
806 } else
807 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
808
809 return err;
810 }
811
812 int fat_sync_inode(struct inode *inode)
813 {
814 return __fat_write_inode(inode, 1);
815 }
816
817 EXPORT_SYMBOL_GPL(fat_sync_inode);
818
819 static int fat_show_options(struct seq_file *m, struct dentry *root);
820 static const struct super_operations fat_sops = {
821 .alloc_inode = fat_alloc_inode,
822 .destroy_inode = fat_destroy_inode,
823 .write_inode = fat_write_inode,
824 .evict_inode = fat_evict_inode,
825 .put_super = fat_put_super,
826 .statfs = fat_statfs,
827 .remount_fs = fat_remount,
828
829 .show_options = fat_show_options,
830 };
831
832 static int fat_show_options(struct seq_file *m, struct dentry *root)
833 {
834 struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
835 struct fat_mount_options *opts = &sbi->options;
836 int isvfat = opts->isvfat;
837
838 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
839 seq_printf(m, ",uid=%u",
840 from_kuid_munged(&init_user_ns, opts->fs_uid));
841 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
842 seq_printf(m, ",gid=%u",
843 from_kgid_munged(&init_user_ns, opts->fs_gid));
844 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
845 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
846 if (opts->allow_utime)
847 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
848 if (sbi->nls_disk)
849 /* strip "cp" prefix from displayed option */
850 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
851 if (isvfat) {
852 if (sbi->nls_io)
853 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
854
855 switch (opts->shortname) {
856 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
857 seq_puts(m, ",shortname=win95");
858 break;
859 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
860 seq_puts(m, ",shortname=winnt");
861 break;
862 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
863 seq_puts(m, ",shortname=mixed");
864 break;
865 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
866 seq_puts(m, ",shortname=lower");
867 break;
868 default:
869 seq_puts(m, ",shortname=unknown");
870 break;
871 }
872 }
873 if (opts->name_check != 'n')
874 seq_printf(m, ",check=%c", opts->name_check);
875 if (opts->usefree)
876 seq_puts(m, ",usefree");
877 if (opts->quiet)
878 seq_puts(m, ",quiet");
879 if (opts->showexec)
880 seq_puts(m, ",showexec");
881 if (opts->sys_immutable)
882 seq_puts(m, ",sys_immutable");
883 if (!isvfat) {
884 if (opts->dotsOK)
885 seq_puts(m, ",dotsOK=yes");
886 if (opts->nocase)
887 seq_puts(m, ",nocase");
888 } else {
889 if (opts->utf8)
890 seq_puts(m, ",utf8");
891 if (opts->unicode_xlate)
892 seq_puts(m, ",uni_xlate");
893 if (!opts->numtail)
894 seq_puts(m, ",nonumtail");
895 if (opts->rodir)
896 seq_puts(m, ",rodir");
897 }
898 if (opts->flush)
899 seq_puts(m, ",flush");
900 if (opts->tz_set) {
901 if (opts->time_offset)
902 seq_printf(m, ",time_offset=%d", opts->time_offset);
903 else
904 seq_puts(m, ",tz=UTC");
905 }
906 if (opts->errors == FAT_ERRORS_CONT)
907 seq_puts(m, ",errors=continue");
908 else if (opts->errors == FAT_ERRORS_PANIC)
909 seq_puts(m, ",errors=panic");
910 else
911 seq_puts(m, ",errors=remount-ro");
912 if (opts->nfs == FAT_NFS_NOSTALE_RO)
913 seq_puts(m, ",nfs=nostale_ro");
914 else if (opts->nfs)
915 seq_puts(m, ",nfs=stale_rw");
916 if (opts->discard)
917 seq_puts(m, ",discard");
918 if (opts->dos1xfloppy)
919 seq_puts(m, ",dos1xfloppy");
920
921 return 0;
922 }
923
924 enum {
925 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
926 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
927 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
928 Opt_immutable, Opt_dots, Opt_nodots,
929 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
930 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
931 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
932 Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
933 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
934 Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
935 };
936
937 static const match_table_t fat_tokens = {
938 {Opt_check_r, "check=relaxed"},
939 {Opt_check_s, "check=strict"},
940 {Opt_check_n, "check=normal"},
941 {Opt_check_r, "check=r"},
942 {Opt_check_s, "check=s"},
943 {Opt_check_n, "check=n"},
944 {Opt_uid, "uid=%u"},
945 {Opt_gid, "gid=%u"},
946 {Opt_umask, "umask=%o"},
947 {Opt_dmask, "dmask=%o"},
948 {Opt_fmask, "fmask=%o"},
949 {Opt_allow_utime, "allow_utime=%o"},
950 {Opt_codepage, "codepage=%u"},
951 {Opt_usefree, "usefree"},
952 {Opt_nocase, "nocase"},
953 {Opt_quiet, "quiet"},
954 {Opt_showexec, "showexec"},
955 {Opt_debug, "debug"},
956 {Opt_immutable, "sys_immutable"},
957 {Opt_flush, "flush"},
958 {Opt_tz_utc, "tz=UTC"},
959 {Opt_time_offset, "time_offset=%d"},
960 {Opt_err_cont, "errors=continue"},
961 {Opt_err_panic, "errors=panic"},
962 {Opt_err_ro, "errors=remount-ro"},
963 {Opt_discard, "discard"},
964 {Opt_nfs_stale_rw, "nfs"},
965 {Opt_nfs_stale_rw, "nfs=stale_rw"},
966 {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
967 {Opt_dos1xfloppy, "dos1xfloppy"},
968 {Opt_obsolete, "conv=binary"},
969 {Opt_obsolete, "conv=text"},
970 {Opt_obsolete, "conv=auto"},
971 {Opt_obsolete, "conv=b"},
972 {Opt_obsolete, "conv=t"},
973 {Opt_obsolete, "conv=a"},
974 {Opt_obsolete, "fat=%u"},
975 {Opt_obsolete, "blocksize=%u"},
976 {Opt_obsolete, "cvf_format=%20s"},
977 {Opt_obsolete, "cvf_options=%100s"},
978 {Opt_obsolete, "posix"},
979 {Opt_err, NULL},
980 };
981 static const match_table_t msdos_tokens = {
982 {Opt_nodots, "nodots"},
983 {Opt_nodots, "dotsOK=no"},
984 {Opt_dots, "dots"},
985 {Opt_dots, "dotsOK=yes"},
986 {Opt_err, NULL}
987 };
988 static const match_table_t vfat_tokens = {
989 {Opt_charset, "iocharset=%s"},
990 {Opt_shortname_lower, "shortname=lower"},
991 {Opt_shortname_win95, "shortname=win95"},
992 {Opt_shortname_winnt, "shortname=winnt"},
993 {Opt_shortname_mixed, "shortname=mixed"},
994 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
995 {Opt_utf8_no, "utf8=no"},
996 {Opt_utf8_no, "utf8=false"},
997 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
998 {Opt_utf8_yes, "utf8=yes"},
999 {Opt_utf8_yes, "utf8=true"},
1000 {Opt_utf8_yes, "utf8"},
1001 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
1002 {Opt_uni_xl_no, "uni_xlate=no"},
1003 {Opt_uni_xl_no, "uni_xlate=false"},
1004 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
1005 {Opt_uni_xl_yes, "uni_xlate=yes"},
1006 {Opt_uni_xl_yes, "uni_xlate=true"},
1007 {Opt_uni_xl_yes, "uni_xlate"},
1008 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
1009 {Opt_nonumtail_no, "nonumtail=no"},
1010 {Opt_nonumtail_no, "nonumtail=false"},
1011 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
1012 {Opt_nonumtail_yes, "nonumtail=yes"},
1013 {Opt_nonumtail_yes, "nonumtail=true"},
1014 {Opt_nonumtail_yes, "nonumtail"},
1015 {Opt_rodir, "rodir"},
1016 {Opt_err, NULL}
1017 };
1018
1019 static int parse_options(struct super_block *sb, char *options, int is_vfat,
1020 int silent, int *debug, struct fat_mount_options *opts)
1021 {
1022 char *p;
1023 substring_t args[MAX_OPT_ARGS];
1024 int option;
1025 char *iocharset;
1026
1027 opts->isvfat = is_vfat;
1028
1029 opts->fs_uid = current_uid();
1030 opts->fs_gid = current_gid();
1031 opts->fs_fmask = opts->fs_dmask = current_umask();
1032 opts->allow_utime = -1;
1033 opts->codepage = fat_default_codepage;
1034 opts->iocharset = fat_default_iocharset;
1035 if (is_vfat) {
1036 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1037 opts->rodir = 0;
1038 } else {
1039 opts->shortname = 0;
1040 opts->rodir = 1;
1041 }
1042 opts->name_check = 'n';
1043 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
1044 opts->utf8 = opts->unicode_xlate = 0;
1045 opts->numtail = 1;
1046 opts->usefree = opts->nocase = 0;
1047 opts->tz_set = 0;
1048 opts->nfs = 0;
1049 opts->errors = FAT_ERRORS_RO;
1050 *debug = 0;
1051
1052 if (!options)
1053 goto out;
1054
1055 while ((p = strsep(&options, ",")) != NULL) {
1056 int token;
1057 if (!*p)
1058 continue;
1059
1060 token = match_token(p, fat_tokens, args);
1061 if (token == Opt_err) {
1062 if (is_vfat)
1063 token = match_token(p, vfat_tokens, args);
1064 else
1065 token = match_token(p, msdos_tokens, args);
1066 }
1067 switch (token) {
1068 case Opt_check_s:
1069 opts->name_check = 's';
1070 break;
1071 case Opt_check_r:
1072 opts->name_check = 'r';
1073 break;
1074 case Opt_check_n:
1075 opts->name_check = 'n';
1076 break;
1077 case Opt_usefree:
1078 opts->usefree = 1;
1079 break;
1080 case Opt_nocase:
1081 if (!is_vfat)
1082 opts->nocase = 1;
1083 else {
1084 /* for backward compatibility */
1085 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1086 | VFAT_SFN_CREATE_WIN95;
1087 }
1088 break;
1089 case Opt_quiet:
1090 opts->quiet = 1;
1091 break;
1092 case Opt_showexec:
1093 opts->showexec = 1;
1094 break;
1095 case Opt_debug:
1096 *debug = 1;
1097 break;
1098 case Opt_immutable:
1099 opts->sys_immutable = 1;
1100 break;
1101 case Opt_uid:
1102 if (match_int(&args[0], &option))
1103 return -EINVAL;
1104 opts->fs_uid = make_kuid(current_user_ns(), option);
1105 if (!uid_valid(opts->fs_uid))
1106 return -EINVAL;
1107 break;
1108 case Opt_gid:
1109 if (match_int(&args[0], &option))
1110 return -EINVAL;
1111 opts->fs_gid = make_kgid(current_user_ns(), option);
1112 if (!gid_valid(opts->fs_gid))
1113 return -EINVAL;
1114 break;
1115 case Opt_umask:
1116 if (match_octal(&args[0], &option))
1117 return -EINVAL;
1118 opts->fs_fmask = opts->fs_dmask = option;
1119 break;
1120 case Opt_dmask:
1121 if (match_octal(&args[0], &option))
1122 return -EINVAL;
1123 opts->fs_dmask = option;
1124 break;
1125 case Opt_fmask:
1126 if (match_octal(&args[0], &option))
1127 return -EINVAL;
1128 opts->fs_fmask = option;
1129 break;
1130 case Opt_allow_utime:
1131 if (match_octal(&args[0], &option))
1132 return -EINVAL;
1133 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1134 break;
1135 case Opt_codepage:
1136 if (match_int(&args[0], &option))
1137 return -EINVAL;
1138 opts->codepage = option;
1139 break;
1140 case Opt_flush:
1141 opts->flush = 1;
1142 break;
1143 case Opt_time_offset:
1144 if (match_int(&args[0], &option))
1145 return -EINVAL;
1146 if (option < -12 * 60 || option > 12 * 60)
1147 return -EINVAL;
1148 opts->tz_set = 1;
1149 opts->time_offset = option;
1150 break;
1151 case Opt_tz_utc:
1152 opts->tz_set = 1;
1153 opts->time_offset = 0;
1154 break;
1155 case Opt_err_cont:
1156 opts->errors = FAT_ERRORS_CONT;
1157 break;
1158 case Opt_err_panic:
1159 opts->errors = FAT_ERRORS_PANIC;
1160 break;
1161 case Opt_err_ro:
1162 opts->errors = FAT_ERRORS_RO;
1163 break;
1164 case Opt_nfs_stale_rw:
1165 opts->nfs = FAT_NFS_STALE_RW;
1166 break;
1167 case Opt_nfs_nostale_ro:
1168 opts->nfs = FAT_NFS_NOSTALE_RO;
1169 break;
1170 case Opt_dos1xfloppy:
1171 opts->dos1xfloppy = 1;
1172 break;
1173
1174 /* msdos specific */
1175 case Opt_dots:
1176 opts->dotsOK = 1;
1177 break;
1178 case Opt_nodots:
1179 opts->dotsOK = 0;
1180 break;
1181
1182 /* vfat specific */
1183 case Opt_charset:
1184 if (opts->iocharset != fat_default_iocharset)
1185 kfree(opts->iocharset);
1186 iocharset = match_strdup(&args[0]);
1187 if (!iocharset)
1188 return -ENOMEM;
1189 opts->iocharset = iocharset;
1190 break;
1191 case Opt_shortname_lower:
1192 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1193 | VFAT_SFN_CREATE_WIN95;
1194 break;
1195 case Opt_shortname_win95:
1196 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1197 | VFAT_SFN_CREATE_WIN95;
1198 break;
1199 case Opt_shortname_winnt:
1200 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1201 | VFAT_SFN_CREATE_WINNT;
1202 break;
1203 case Opt_shortname_mixed:
1204 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1205 | VFAT_SFN_CREATE_WIN95;
1206 break;
1207 case Opt_utf8_no: /* 0 or no or false */
1208 opts->utf8 = 0;
1209 break;
1210 case Opt_utf8_yes: /* empty or 1 or yes or true */
1211 opts->utf8 = 1;
1212 break;
1213 case Opt_uni_xl_no: /* 0 or no or false */
1214 opts->unicode_xlate = 0;
1215 break;
1216 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1217 opts->unicode_xlate = 1;
1218 break;
1219 case Opt_nonumtail_no: /* 0 or no or false */
1220 opts->numtail = 1; /* negated option */
1221 break;
1222 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1223 opts->numtail = 0; /* negated option */
1224 break;
1225 case Opt_rodir:
1226 opts->rodir = 1;
1227 break;
1228 case Opt_discard:
1229 opts->discard = 1;
1230 break;
1231
1232 /* obsolete mount options */
1233 case Opt_obsolete:
1234 fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1235 "not supported now", p);
1236 break;
1237 /* unknown option */
1238 default:
1239 if (!silent) {
1240 fat_msg(sb, KERN_ERR,
1241 "Unrecognized mount option \"%s\" "
1242 "or missing value", p);
1243 }
1244 return -EINVAL;
1245 }
1246 }
1247
1248 out:
1249 /* UTF-8 doesn't provide FAT semantics */
1250 if (!strcmp(opts->iocharset, "utf8")) {
1251 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1252 " for FAT filesystems, filesystem will be "
1253 "case sensitive!");
1254 }
1255
1256 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1257 if (opts->allow_utime == (unsigned short)-1)
1258 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1259 if (opts->unicode_xlate)
1260 opts->utf8 = 0;
1261 if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1262 sb->s_flags |= MS_RDONLY;
1263 sb->s_export_op = &fat_export_ops_nostale;
1264 }
1265
1266 return 0;
1267 }
1268
1269 static int fat_read_root(struct inode *inode)
1270 {
1271 struct super_block *sb = inode->i_sb;
1272 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1273 int error;
1274
1275 MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1276 inode->i_uid = sbi->options.fs_uid;
1277 inode->i_gid = sbi->options.fs_gid;
1278 inode->i_version++;
1279 inode->i_generation = 0;
1280 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1281 inode->i_op = sbi->dir_ops;
1282 inode->i_fop = &fat_dir_operations;
1283 if (sbi->fat_bits == 32) {
1284 MSDOS_I(inode)->i_start = sbi->root_cluster;
1285 error = fat_calc_dir_size(inode);
1286 if (error < 0)
1287 return error;
1288 } else {
1289 MSDOS_I(inode)->i_start = 0;
1290 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1291 }
1292 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1293 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1294 MSDOS_I(inode)->i_logstart = 0;
1295 MSDOS_I(inode)->mmu_private = inode->i_size;
1296
1297 fat_save_attrs(inode, ATTR_DIR);
1298 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1299 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1300 set_nlink(inode, fat_subdirs(inode)+2);
1301
1302 return 0;
1303 }
1304
1305 static unsigned long calc_fat_clusters(struct super_block *sb)
1306 {
1307 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1308
1309 /* Divide first to avoid overflow */
1310 if (sbi->fat_bits != 12) {
1311 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1312 return ent_per_sec * sbi->fat_length;
1313 }
1314
1315 return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1316 }
1317
1318 static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1319 {
1320 if (get_unaligned_le16(&b->sector_size))
1321 return false;
1322 if (b->sec_per_clus)
1323 return false;
1324 if (b->reserved)
1325 return false;
1326 if (b->fats)
1327 return false;
1328 if (get_unaligned_le16(&b->dir_entries))
1329 return false;
1330 if (get_unaligned_le16(&b->sectors))
1331 return false;
1332 if (b->media)
1333 return false;
1334 if (b->fat_length)
1335 return false;
1336 if (b->secs_track)
1337 return false;
1338 if (b->heads)
1339 return false;
1340 return true;
1341 }
1342
1343 static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1344 int silent, struct fat_bios_param_block *bpb)
1345 {
1346 int error = -EINVAL;
1347
1348 /* Read in BPB ... */
1349 memset(bpb, 0, sizeof(*bpb));
1350 bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1351 bpb->fat_sec_per_clus = b->sec_per_clus;
1352 bpb->fat_reserved = le16_to_cpu(b->reserved);
1353 bpb->fat_fats = b->fats;
1354 bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1355 bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1356 bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1357 bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1358
1359 bpb->fat16_state = b->fat16.state;
1360 bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1361
1362 bpb->fat32_length = le32_to_cpu(b->fat32.length);
1363 bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1364 bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1365 bpb->fat32_state = b->fat32.state;
1366 bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1367
1368 /* Validate this looks like a FAT filesystem BPB */
1369 if (!bpb->fat_reserved) {
1370 if (!silent)
1371 fat_msg(sb, KERN_ERR,
1372 "bogus number of reserved sectors");
1373 goto out;
1374 }
1375 if (!bpb->fat_fats) {
1376 if (!silent)
1377 fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1378 goto out;
1379 }
1380
1381 /*
1382 * Earlier we checked here that b->secs_track and b->head are nonzero,
1383 * but it turns out valid FAT filesystems can have zero there.
1384 */
1385
1386 if (!fat_valid_media(b->media)) {
1387 if (!silent)
1388 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1389 (unsigned)b->media);
1390 goto out;
1391 }
1392
1393 if (!is_power_of_2(bpb->fat_sector_size)
1394 || (bpb->fat_sector_size < 512)
1395 || (bpb->fat_sector_size > 4096)) {
1396 if (!silent)
1397 fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1398 (unsigned)bpb->fat_sector_size);
1399 goto out;
1400 }
1401
1402 if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1403 if (!silent)
1404 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1405 (unsigned)bpb->fat_sec_per_clus);
1406 goto out;
1407 }
1408
1409 error = 0;
1410
1411 out:
1412 return error;
1413 }
1414
1415 static int fat_read_static_bpb(struct super_block *sb,
1416 struct fat_boot_sector *b, int silent,
1417 struct fat_bios_param_block *bpb)
1418 {
1419 static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1420
1421 struct fat_floppy_defaults *fdefaults = NULL;
1422 int error = -EINVAL;
1423 sector_t bd_sects;
1424 unsigned i;
1425
1426 bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE;
1427
1428 /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1429 if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1430 if (!silent)
1431 fat_msg(sb, KERN_ERR,
1432 "%s; no bootstrapping code", notdos1x);
1433 goto out;
1434 }
1435
1436 /*
1437 * If any value in this region is non-zero, it isn't archaic
1438 * DOS.
1439 */
1440 if (!fat_bpb_is_zero(b)) {
1441 if (!silent)
1442 fat_msg(sb, KERN_ERR,
1443 "%s; DOS 2.x BPB is non-zero", notdos1x);
1444 goto out;
1445 }
1446
1447 for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1448 if (floppy_defaults[i].nr_sectors == bd_sects) {
1449 fdefaults = &floppy_defaults[i];
1450 break;
1451 }
1452 }
1453
1454 if (fdefaults == NULL) {
1455 if (!silent)
1456 fat_msg(sb, KERN_WARNING,
1457 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1458 (u64)bd_sects);
1459 goto out;
1460 }
1461
1462 if (!silent)
1463 fat_msg(sb, KERN_INFO,
1464 "This looks like a DOS 1.x volume; assuming default BPB values");
1465
1466 memset(bpb, 0, sizeof(*bpb));
1467 bpb->fat_sector_size = SECTOR_SIZE;
1468 bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1469 bpb->fat_reserved = 1;
1470 bpb->fat_fats = 2;
1471 bpb->fat_dir_entries = fdefaults->dir_entries;
1472 bpb->fat_sectors = fdefaults->nr_sectors;
1473 bpb->fat_fat_length = fdefaults->fat_length;
1474
1475 error = 0;
1476
1477 out:
1478 return error;
1479 }
1480
1481 /*
1482 * Read the super block of an MS-DOS FS.
1483 */
1484 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1485 void (*setup)(struct super_block *))
1486 {
1487 struct inode *root_inode = NULL, *fat_inode = NULL;
1488 struct inode *fsinfo_inode = NULL;
1489 struct buffer_head *bh;
1490 struct fat_bios_param_block bpb;
1491 struct msdos_sb_info *sbi;
1492 u16 logical_sector_size;
1493 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1494 int debug;
1495 long error;
1496 char buf[50];
1497
1498 /*
1499 * GFP_KERNEL is ok here, because while we do hold the
1500 * supeblock lock, memory pressure can't call back into
1501 * the filesystem, since we're only just about to mount
1502 * it and have no inodes etc active!
1503 */
1504 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1505 if (!sbi)
1506 return -ENOMEM;
1507 sb->s_fs_info = sbi;
1508
1509 sb->s_flags |= MS_NODIRATIME;
1510 sb->s_magic = MSDOS_SUPER_MAGIC;
1511 sb->s_op = &fat_sops;
1512 sb->s_export_op = &fat_export_ops;
1513 mutex_init(&sbi->nfs_build_inode_lock);
1514 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1515 DEFAULT_RATELIMIT_BURST);
1516
1517 error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1518 if (error)
1519 goto out_fail;
1520
1521 setup(sb); /* flavour-specific stuff that needs options */
1522
1523 error = -EIO;
1524 sb_min_blocksize(sb, 512);
1525 bh = sb_bread(sb, 0);
1526 if (bh == NULL) {
1527 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1528 goto out_fail;
1529 }
1530
1531 error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1532 &bpb);
1533 if (error == -EINVAL && sbi->options.dos1xfloppy)
1534 error = fat_read_static_bpb(sb,
1535 (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1536 brelse(bh);
1537
1538 if (error == -EINVAL)
1539 goto out_invalid;
1540 else if (error)
1541 goto out_fail;
1542
1543 logical_sector_size = bpb.fat_sector_size;
1544 sbi->sec_per_clus = bpb.fat_sec_per_clus;
1545
1546 error = -EIO;
1547 if (logical_sector_size < sb->s_blocksize) {
1548 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1549 " (logical sector size = %u)", logical_sector_size);
1550 goto out_fail;
1551 }
1552
1553 if (logical_sector_size > sb->s_blocksize) {
1554 struct buffer_head *bh_resize;
1555
1556 if (!sb_set_blocksize(sb, logical_sector_size)) {
1557 fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1558 logical_sector_size);
1559 goto out_fail;
1560 }
1561
1562 /* Verify that the larger boot sector is fully readable */
1563 bh_resize = sb_bread(sb, 0);
1564 if (bh_resize == NULL) {
1565 fat_msg(sb, KERN_ERR, "unable to read boot sector"
1566 " (logical sector size = %lu)",
1567 sb->s_blocksize);
1568 goto out_fail;
1569 }
1570 brelse(bh_resize);
1571 }
1572
1573 mutex_init(&sbi->s_lock);
1574 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1575 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1576 sbi->fats = bpb.fat_fats;
1577 sbi->fat_bits = 0; /* Don't know yet */
1578 sbi->fat_start = bpb.fat_reserved;
1579 sbi->fat_length = bpb.fat_fat_length;
1580 sbi->root_cluster = 0;
1581 sbi->free_clusters = -1; /* Don't know yet */
1582 sbi->free_clus_valid = 0;
1583 sbi->prev_free = FAT_START_ENT;
1584 sb->s_maxbytes = 0xffffffff;
1585
1586 if (!sbi->fat_length && bpb.fat32_length) {
1587 struct fat_boot_fsinfo *fsinfo;
1588 struct buffer_head *fsinfo_bh;
1589
1590 /* Must be FAT32 */
1591 sbi->fat_bits = 32;
1592 sbi->fat_length = bpb.fat32_length;
1593 sbi->root_cluster = bpb.fat32_root_cluster;
1594
1595 /* MC - if info_sector is 0, don't multiply by 0 */
1596 sbi->fsinfo_sector = bpb.fat32_info_sector;
1597 if (sbi->fsinfo_sector == 0)
1598 sbi->fsinfo_sector = 1;
1599
1600 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1601 if (fsinfo_bh == NULL) {
1602 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1603 " (sector = %lu)", sbi->fsinfo_sector);
1604 goto out_fail;
1605 }
1606
1607 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1608 if (!IS_FSINFO(fsinfo)) {
1609 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1610 "0x%08x, 0x%08x (sector = %lu)",
1611 le32_to_cpu(fsinfo->signature1),
1612 le32_to_cpu(fsinfo->signature2),
1613 sbi->fsinfo_sector);
1614 } else {
1615 if (sbi->options.usefree)
1616 sbi->free_clus_valid = 1;
1617 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1618 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1619 }
1620
1621 brelse(fsinfo_bh);
1622 }
1623
1624 /* interpret volume ID as a little endian 32 bit integer */
1625 if (sbi->fat_bits == 32)
1626 sbi->vol_id = bpb.fat32_vol_id;
1627 else /* fat 16 or 12 */
1628 sbi->vol_id = bpb.fat16_vol_id;
1629
1630 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1631 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1632
1633 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1634 sbi->dir_entries = bpb.fat_dir_entries;
1635 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1636 if (!silent)
1637 fat_msg(sb, KERN_ERR, "bogus directory-entries per block"
1638 " (%u)", sbi->dir_entries);
1639 goto out_invalid;
1640 }
1641
1642 rootdir_sectors = sbi->dir_entries
1643 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1644 sbi->data_start = sbi->dir_start + rootdir_sectors;
1645 total_sectors = bpb.fat_sectors;
1646 if (total_sectors == 0)
1647 total_sectors = bpb.fat_total_sect;
1648
1649 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1650
1651 if (sbi->fat_bits != 32)
1652 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1653
1654 /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1655 if (sbi->fat_bits == 32)
1656 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1657 else /* fat 16 or 12 */
1658 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1659
1660 /* check that FAT table does not overflow */
1661 fat_clusters = calc_fat_clusters(sb);
1662 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1663 if (total_clusters > MAX_FAT(sb)) {
1664 if (!silent)
1665 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1666 total_clusters);
1667 goto out_invalid;
1668 }
1669
1670 sbi->max_cluster = total_clusters + FAT_START_ENT;
1671 /* check the free_clusters, it's not necessarily correct */
1672 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1673 sbi->free_clusters = -1;
1674 /* check the prev_free, it's not necessarily correct */
1675 sbi->prev_free %= sbi->max_cluster;
1676 if (sbi->prev_free < FAT_START_ENT)
1677 sbi->prev_free = FAT_START_ENT;
1678
1679 /* set up enough so that it can read an inode */
1680 fat_hash_init(sb);
1681 dir_hash_init(sb);
1682 fat_ent_access_init(sb);
1683
1684 /*
1685 * The low byte of FAT's first entry must have same value with
1686 * media-field. But in real world, too many devices is
1687 * writing wrong value. So, removed that validity check.
1688 *
1689 * if (FAT_FIRST_ENT(sb, media) != first)
1690 */
1691
1692 error = -EINVAL;
1693 sprintf(buf, "cp%d", sbi->options.codepage);
1694 sbi->nls_disk = load_nls(buf);
1695 if (!sbi->nls_disk) {
1696 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1697 goto out_fail;
1698 }
1699
1700 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1701 if (sbi->options.isvfat) {
1702 sbi->nls_io = load_nls(sbi->options.iocharset);
1703 if (!sbi->nls_io) {
1704 fat_msg(sb, KERN_ERR, "IO charset %s not found",
1705 sbi->options.iocharset);
1706 goto out_fail;
1707 }
1708 }
1709
1710 error = -ENOMEM;
1711 fat_inode = new_inode(sb);
1712 if (!fat_inode)
1713 goto out_fail;
1714 MSDOS_I(fat_inode)->i_pos = 0;
1715 sbi->fat_inode = fat_inode;
1716
1717 fsinfo_inode = new_inode(sb);
1718 if (!fsinfo_inode)
1719 goto out_fail;
1720 fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1721 sbi->fsinfo_inode = fsinfo_inode;
1722 insert_inode_hash(fsinfo_inode);
1723
1724 root_inode = new_inode(sb);
1725 if (!root_inode)
1726 goto out_fail;
1727 root_inode->i_ino = MSDOS_ROOT_INO;
1728 root_inode->i_version = 1;
1729 error = fat_read_root(root_inode);
1730 if (error < 0) {
1731 iput(root_inode);
1732 goto out_fail;
1733 }
1734 error = -ENOMEM;
1735 insert_inode_hash(root_inode);
1736 fat_attach(root_inode, 0);
1737 sb->s_root = d_make_root(root_inode);
1738 if (!sb->s_root) {
1739 fat_msg(sb, KERN_ERR, "get root inode failed");
1740 goto out_fail;
1741 }
1742
1743 if (sbi->options.discard) {
1744 struct request_queue *q = bdev_get_queue(sb->s_bdev);
1745 if (!blk_queue_discard(q))
1746 fat_msg(sb, KERN_WARNING,
1747 "mounting with \"discard\" option, but "
1748 "the device does not support discard");
1749 }
1750
1751 fat_set_state(sb, 1, 0);
1752 return 0;
1753
1754 out_invalid:
1755 error = -EINVAL;
1756 if (!silent)
1757 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1758
1759 out_fail:
1760 if (fsinfo_inode)
1761 iput(fsinfo_inode);
1762 if (fat_inode)
1763 iput(fat_inode);
1764 unload_nls(sbi->nls_io);
1765 unload_nls(sbi->nls_disk);
1766 if (sbi->options.iocharset != fat_default_iocharset)
1767 kfree(sbi->options.iocharset);
1768 sb->s_fs_info = NULL;
1769 kfree(sbi);
1770 return error;
1771 }
1772
1773 EXPORT_SYMBOL_GPL(fat_fill_super);
1774
1775 /*
1776 * helper function for fat_flush_inodes. This writes both the inode
1777 * and the file data blocks, waiting for in flight data blocks before
1778 * the start of the call. It does not wait for any io started
1779 * during the call
1780 */
1781 static int writeback_inode(struct inode *inode)
1782 {
1783
1784 int ret;
1785
1786 /* if we used wait=1, sync_inode_metadata waits for the io for the
1787 * inode to finish. So wait=0 is sent down to sync_inode_metadata
1788 * and filemap_fdatawrite is used for the data blocks
1789 */
1790 ret = sync_inode_metadata(inode, 0);
1791 if (!ret)
1792 ret = filemap_fdatawrite(inode->i_mapping);
1793 return ret;
1794 }
1795
1796 /*
1797 * write data and metadata corresponding to i1 and i2. The io is
1798 * started but we do not wait for any of it to finish.
1799 *
1800 * filemap_flush is used for the block device, so if there is a dirty
1801 * page for a block already in flight, we will not wait and start the
1802 * io over again
1803 */
1804 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1805 {
1806 int ret = 0;
1807 if (!MSDOS_SB(sb)->options.flush)
1808 return 0;
1809 if (i1)
1810 ret = writeback_inode(i1);
1811 if (!ret && i2)
1812 ret = writeback_inode(i2);
1813 if (!ret) {
1814 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1815 ret = filemap_flush(mapping);
1816 }
1817 return ret;
1818 }
1819 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1820
1821 static int __init init_fat_fs(void)
1822 {
1823 int err;
1824
1825 err = fat_cache_init();
1826 if (err)
1827 return err;
1828
1829 err = fat_init_inodecache();
1830 if (err)
1831 goto failed;
1832
1833 return 0;
1834
1835 failed:
1836 fat_cache_destroy();
1837 return err;
1838 }
1839
1840 static void __exit exit_fat_fs(void)
1841 {
1842 fat_cache_destroy();
1843 fat_destroy_inodecache();
1844 }
1845
1846 module_init(init_fat_fs)
1847 module_exit(exit_fat_fs)
1848
1849 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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