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Linux 4.3-rc5
[linux/fpc-iii.git] / fs / fat / inode.c
blob509411dd3698959c0b8c387dcf0f487b5da12abe
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/pagemap.h>
15 #include <linux/mpage.h>
16 #include <linux/vfs.h>
17 #include <linux/seq_file.h>
18 #include <linux/parser.h>
19 #include <linux/uio.h>
20 #include <linux/blkdev.h>
21 #include <linux/backing-dev.h>
22 #include <asm/unaligned.h>
23 #include "fat.h"
24
25 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
26 /* if user don't select VFAT, this is undefined. */
27 #define CONFIG_FAT_DEFAULT_IOCHARSET ""
28 #endif
29
30 #define KB_IN_SECTORS 2
31
32 /*
33 * A deserialized copy of the on-disk structure laid out in struct
34 * fat_boot_sector.
35 */
36 struct fat_bios_param_block {
37 u16 fat_sector_size;
38 u8 fat_sec_per_clus;
39 u16 fat_reserved;
40 u8 fat_fats;
41 u16 fat_dir_entries;
42 u16 fat_sectors;
43 u16 fat_fat_length;
44 u32 fat_total_sect;
45
46 u8 fat16_state;
47 u32 fat16_vol_id;
48
49 u32 fat32_length;
50 u32 fat32_root_cluster;
51 u16 fat32_info_sector;
52 u8 fat32_state;
53 u32 fat32_vol_id;
54 };
55
56 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
57 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
58
59 static struct fat_floppy_defaults {
60 unsigned nr_sectors;
61 unsigned sec_per_clus;
62 unsigned dir_entries;
63 unsigned media;
64 unsigned fat_length;
65 } floppy_defaults[] = {
66 {
67 .nr_sectors = 160 * KB_IN_SECTORS,
68 .sec_per_clus = 1,
69 .dir_entries = 64,
70 .media = 0xFE,
71 .fat_length = 1,
72 },
73 {
74 .nr_sectors = 180 * KB_IN_SECTORS,
75 .sec_per_clus = 1,
76 .dir_entries = 64,
77 .media = 0xFC,
78 .fat_length = 2,
79 },
80 {
81 .nr_sectors = 320 * KB_IN_SECTORS,
82 .sec_per_clus = 2,
83 .dir_entries = 112,
84 .media = 0xFF,
85 .fat_length = 1,
86 },
87 {
88 .nr_sectors = 360 * KB_IN_SECTORS,
89 .sec_per_clus = 2,
90 .dir_entries = 112,
91 .media = 0xFD,
92 .fat_length = 2,
93 },
94 };
95
96 static int fat_add_cluster(struct inode *inode)
97 {
98 int err, cluster;
99
100 err = fat_alloc_clusters(inode, &cluster, 1);
101 if (err)
102 return err;
103 /* FIXME: this cluster should be added after data of this
104 * cluster is writed */
105 err = fat_chain_add(inode, cluster, 1);
106 if (err)
107 fat_free_clusters(inode, cluster);
108 return err;
109 }
110
111 static inline int __fat_get_block(struct inode *inode, sector_t iblock,
112 unsigned long *max_blocks,
113 struct buffer_head *bh_result, int create)
114 {
115 struct super_block *sb = inode->i_sb;
116 struct msdos_sb_info *sbi = MSDOS_SB(sb);
117 unsigned long mapped_blocks;
118 sector_t phys;
119 int err, offset;
120
121 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
122 if (err)
123 return err;
124 if (phys) {
125 map_bh(bh_result, sb, phys);
126 *max_blocks = min(mapped_blocks, *max_blocks);
127 return 0;
128 }
129 if (!create)
130 return 0;
131
132 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
133 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
134 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
135 return -EIO;
136 }
137
138 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
139 if (!offset) {
140 /* TODO: multiple cluster allocation would be desirable. */
141 err = fat_add_cluster(inode);
142 if (err)
143 return err;
144 }
145 /* available blocks on this cluster */
146 mapped_blocks = sbi->sec_per_clus - offset;
147
148 *max_blocks = min(mapped_blocks, *max_blocks);
149 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
150
151 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
152 if (err)
153 return err;
154
155 BUG_ON(!phys);
156 BUG_ON(*max_blocks != mapped_blocks);
157 set_buffer_new(bh_result);
158 map_bh(bh_result, sb, phys);
159
160 return 0;
161 }
162
163 static int fat_get_block(struct inode *inode, sector_t iblock,
164 struct buffer_head *bh_result, int create)
165 {
166 struct super_block *sb = inode->i_sb;
167 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
168 int err;
169
170 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
171 if (err)
172 return err;
173 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
174 return 0;
175 }
176
177 static int fat_writepage(struct page *page, struct writeback_control *wbc)
178 {
179 return block_write_full_page(page, fat_get_block, wbc);
180 }
181
182 static int fat_writepages(struct address_space *mapping,
183 struct writeback_control *wbc)
184 {
185 return mpage_writepages(mapping, wbc, fat_get_block);
186 }
187
188 static int fat_readpage(struct file *file, struct page *page)
189 {
190 return mpage_readpage(page, fat_get_block);
191 }
192
193 static int fat_readpages(struct file *file, struct address_space *mapping,
194 struct list_head *pages, unsigned nr_pages)
195 {
196 return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
197 }
198
199 static void fat_write_failed(struct address_space *mapping, loff_t to)
200 {
201 struct inode *inode = mapping->host;
202
203 if (to > inode->i_size) {
204 truncate_pagecache(inode, inode->i_size);
205 fat_truncate_blocks(inode, inode->i_size);
206 }
207 }
208
209 static int fat_write_begin(struct file *file, struct address_space *mapping,
210 loff_t pos, unsigned len, unsigned flags,
211 struct page **pagep, void **fsdata)
212 {
213 int err;
214
215 *pagep = NULL;
216 err = cont_write_begin(file, mapping, pos, len, flags,
217 pagep, fsdata, fat_get_block,
218 &MSDOS_I(mapping->host)->mmu_private);
219 if (err < 0)
220 fat_write_failed(mapping, pos + len);
221 return err;
222 }
223
224 static int fat_write_end(struct file *file, struct address_space *mapping,
225 loff_t pos, unsigned len, unsigned copied,
226 struct page *pagep, void *fsdata)
227 {
228 struct inode *inode = mapping->host;
229 int err;
230 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
231 if (err < len)
232 fat_write_failed(mapping, pos + len);
233 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
234 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
235 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
236 mark_inode_dirty(inode);
237 }
238 return err;
239 }
240
241 static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
242 loff_t offset)
243 {
244 struct file *file = iocb->ki_filp;
245 struct address_space *mapping = file->f_mapping;
246 struct inode *inode = mapping->host;
247 size_t count = iov_iter_count(iter);
248 ssize_t ret;
249
250 if (iov_iter_rw(iter) == WRITE) {
251 /*
252 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
253 * so we need to update the ->mmu_private to block boundary.
254 *
255 * But we must fill the remaining area or hole by nul for
256 * updating ->mmu_private.
257 *
258 * Return 0, and fallback to normal buffered write.
259 */
260 loff_t size = offset + count;
261 if (MSDOS_I(inode)->mmu_private < size)
262 return 0;
263 }
264
265 /*
266 * FAT need to use the DIO_LOCKING for avoiding the race
267 * condition of fat_get_block() and ->truncate().
268 */
269 ret = blockdev_direct_IO(iocb, inode, iter, offset, fat_get_block);
270 if (ret < 0 && iov_iter_rw(iter) == WRITE)
271 fat_write_failed(mapping, offset + count);
272
273 return ret;
274 }
275
276 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
277 {
278 sector_t blocknr;
279
280 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
281 down_read(&MSDOS_I(mapping->host)->truncate_lock);
282 blocknr = generic_block_bmap(mapping, block, fat_get_block);
283 up_read(&MSDOS_I(mapping->host)->truncate_lock);
284
285 return blocknr;
286 }
287
288 /*
289 * fat_block_truncate_page() zeroes out a mapping from file offset `from'
290 * up to the end of the block which corresponds to `from'.
291 * This is required during truncate to physically zeroout the tail end
292 * of that block so it doesn't yield old data if the file is later grown.
293 * Also, avoid causing failure from fsx for cases of "data past EOF"
294 */
295 int fat_block_truncate_page(struct inode *inode, loff_t from)
296 {
297 return block_truncate_page(inode->i_mapping, from, fat_get_block);
298 }
299
300 static const struct address_space_operations fat_aops = {
301 .readpage = fat_readpage,
302 .readpages = fat_readpages,
303 .writepage = fat_writepage,
304 .writepages = fat_writepages,
305 .write_begin = fat_write_begin,
306 .write_end = fat_write_end,
307 .direct_IO = fat_direct_IO,
308 .bmap = _fat_bmap
309 };
310
311 /*
312 * New FAT inode stuff. We do the following:
313 * a) i_ino is constant and has nothing with on-disk location.
314 * b) FAT manages its own cache of directory entries.
315 * c) *This* cache is indexed by on-disk location.
316 * d) inode has an associated directory entry, all right, but
317 * it may be unhashed.
318 * e) currently entries are stored within struct inode. That should
319 * change.
320 * f) we deal with races in the following way:
321 * 1. readdir() and lookup() do FAT-dir-cache lookup.
322 * 2. rename() unhashes the F-d-c entry and rehashes it in
323 * a new place.
324 * 3. unlink() and rmdir() unhash F-d-c entry.
325 * 4. fat_write_inode() checks whether the thing is unhashed.
326 * If it is we silently return. If it isn't we do bread(),
327 * check if the location is still valid and retry if it
328 * isn't. Otherwise we do changes.
329 * 5. Spinlock is used to protect hash/unhash/location check/lookup
330 * 6. fat_evict_inode() unhashes the F-d-c entry.
331 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
332 * and consider negative result as cache miss.
333 */
334
335 static void fat_hash_init(struct super_block *sb)
336 {
337 struct msdos_sb_info *sbi = MSDOS_SB(sb);
338 int i;
339
340 spin_lock_init(&sbi->inode_hash_lock);
341 for (i = 0; i < FAT_HASH_SIZE; i++)
342 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
343 }
344
345 static inline unsigned long fat_hash(loff_t i_pos)
346 {
347 return hash_32(i_pos, FAT_HASH_BITS);
348 }
349
350 static void dir_hash_init(struct super_block *sb)
351 {
352 struct msdos_sb_info *sbi = MSDOS_SB(sb);
353 int i;
354
355 spin_lock_init(&sbi->dir_hash_lock);
356 for (i = 0; i < FAT_HASH_SIZE; i++)
357 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
358 }
359
360 void fat_attach(struct inode *inode, loff_t i_pos)
361 {
362 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
363
364 if (inode->i_ino != MSDOS_ROOT_INO) {
365 struct hlist_head *head = sbi->inode_hashtable
366 + fat_hash(i_pos);
367
368 spin_lock(&sbi->inode_hash_lock);
369 MSDOS_I(inode)->i_pos = i_pos;
370 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
371 spin_unlock(&sbi->inode_hash_lock);
372 }
373
374 /* If NFS support is enabled, cache the mapping of start cluster
375 * to directory inode. This is used during reconnection of
376 * dentries to the filesystem root.
377 */
378 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
379 struct hlist_head *d_head = sbi->dir_hashtable;
380 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
381
382 spin_lock(&sbi->dir_hash_lock);
383 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
384 spin_unlock(&sbi->dir_hash_lock);
385 }
386 }
387 EXPORT_SYMBOL_GPL(fat_attach);
388
389 void fat_detach(struct inode *inode)
390 {
391 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
392 spin_lock(&sbi->inode_hash_lock);
393 MSDOS_I(inode)->i_pos = 0;
394 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
395 spin_unlock(&sbi->inode_hash_lock);
396
397 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
398 spin_lock(&sbi->dir_hash_lock);
399 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
400 spin_unlock(&sbi->dir_hash_lock);
401 }
402 }
403 EXPORT_SYMBOL_GPL(fat_detach);
404
405 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
406 {
407 struct msdos_sb_info *sbi = MSDOS_SB(sb);
408 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
409 struct msdos_inode_info *i;
410 struct inode *inode = NULL;
411
412 spin_lock(&sbi->inode_hash_lock);
413 hlist_for_each_entry(i, head, i_fat_hash) {
414 BUG_ON(i->vfs_inode.i_sb != sb);
415 if (i->i_pos != i_pos)
416 continue;
417 inode = igrab(&i->vfs_inode);
418 if (inode)
419 break;
420 }
421 spin_unlock(&sbi->inode_hash_lock);
422 return inode;
423 }
424
425 static int is_exec(unsigned char *extension)
426 {
427 unsigned char exe_extensions[] = "EXECOMBAT", *walk;
428
429 for (walk = exe_extensions; *walk; walk += 3)
430 if (!strncmp(extension, walk, 3))
431 return 1;
432 return 0;
433 }
434
435 static int fat_calc_dir_size(struct inode *inode)
436 {
437 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
438 int ret, fclus, dclus;
439
440 inode->i_size = 0;
441 if (MSDOS_I(inode)->i_start == 0)
442 return 0;
443
444 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
445 if (ret < 0)
446 return ret;
447 inode->i_size = (fclus + 1) << sbi->cluster_bits;
448
449 return 0;
450 }
451
452 /* doesn't deal with root inode */
453 int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
454 {
455 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
456 int error;
457
458 MSDOS_I(inode)->i_pos = 0;
459 inode->i_uid = sbi->options.fs_uid;
460 inode->i_gid = sbi->options.fs_gid;
461 inode->i_version++;
462 inode->i_generation = get_seconds();
463
464 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
465 inode->i_generation &= ~1;
466 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
467 inode->i_op = sbi->dir_ops;
468 inode->i_fop = &fat_dir_operations;
469
470 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
471 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
472 error = fat_calc_dir_size(inode);
473 if (error < 0)
474 return error;
475 MSDOS_I(inode)->mmu_private = inode->i_size;
476
477 set_nlink(inode, fat_subdirs(inode));
478 } else { /* not a directory */
479 inode->i_generation |= 1;
480 inode->i_mode = fat_make_mode(sbi, de->attr,
481 ((sbi->options.showexec && !is_exec(de->name + 8))
482 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
483 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
484
485 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
486 inode->i_size = le32_to_cpu(de->size);
487 inode->i_op = &fat_file_inode_operations;
488 inode->i_fop = &fat_file_operations;
489 inode->i_mapping->a_ops = &fat_aops;
490 MSDOS_I(inode)->mmu_private = inode->i_size;
491 }
492 if (de->attr & ATTR_SYS) {
493 if (sbi->options.sys_immutable)
494 inode->i_flags |= S_IMMUTABLE;
495 }
496 fat_save_attrs(inode, de->attr);
497
498 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
499 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
500
501 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
502 if (sbi->options.isvfat) {
503 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
504 de->cdate, de->ctime_cs);
505 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
506 } else
507 inode->i_ctime = inode->i_atime = inode->i_mtime;
508
509 return 0;
510 }
511
512 static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
513 {
514 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
515 mutex_lock(&sbi->nfs_build_inode_lock);
516 }
517
518 static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
519 {
520 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
521 mutex_unlock(&sbi->nfs_build_inode_lock);
522 }
523
524 struct inode *fat_build_inode(struct super_block *sb,
525 struct msdos_dir_entry *de, loff_t i_pos)
526 {
527 struct inode *inode;
528 int err;
529
530 fat_lock_build_inode(MSDOS_SB(sb));
531 inode = fat_iget(sb, i_pos);
532 if (inode)
533 goto out;
534 inode = new_inode(sb);
535 if (!inode) {
536 inode = ERR_PTR(-ENOMEM);
537 goto out;
538 }
539 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
540 inode->i_version = 1;
541 err = fat_fill_inode(inode, de);
542 if (err) {
543 iput(inode);
544 inode = ERR_PTR(err);
545 goto out;
546 }
547 fat_attach(inode, i_pos);
548 insert_inode_hash(inode);
549 out:
550 fat_unlock_build_inode(MSDOS_SB(sb));
551 return inode;
552 }
553
554 EXPORT_SYMBOL_GPL(fat_build_inode);
555
556 static void fat_evict_inode(struct inode *inode)
557 {
558 truncate_inode_pages_final(&inode->i_data);
559 if (!inode->i_nlink) {
560 inode->i_size = 0;
561 fat_truncate_blocks(inode, 0);
562 }
563 invalidate_inode_buffers(inode);
564 clear_inode(inode);
565 fat_cache_inval_inode(inode);
566 fat_detach(inode);
567 }
568
569 static void fat_set_state(struct super_block *sb,
570 unsigned int set, unsigned int force)
571 {
572 struct buffer_head *bh;
573 struct fat_boot_sector *b;
574 struct msdos_sb_info *sbi = MSDOS_SB(sb);
575
576 /* do not change any thing if mounted read only */
577 if ((sb->s_flags & MS_RDONLY) && !force)
578 return;
579
580 /* do not change state if fs was dirty */
581 if (sbi->dirty) {
582 /* warn only on set (mount). */
583 if (set)
584 fat_msg(sb, KERN_WARNING, "Volume was not properly "
585 "unmounted. Some data may be corrupt. "
586 "Please run fsck.");
587 return;
588 }
589
590 bh = sb_bread(sb, 0);
591 if (bh == NULL) {
592 fat_msg(sb, KERN_ERR, "unable to read boot sector "
593 "to mark fs as dirty");
594 return;
595 }
596
597 b = (struct fat_boot_sector *) bh->b_data;
598
599 if (sbi->fat_bits == 32) {
600 if (set)
601 b->fat32.state |= FAT_STATE_DIRTY;
602 else
603 b->fat32.state &= ~FAT_STATE_DIRTY;
604 } else /* fat 16 and 12 */ {
605 if (set)
606 b->fat16.state |= FAT_STATE_DIRTY;
607 else
608 b->fat16.state &= ~FAT_STATE_DIRTY;
609 }
610
611 mark_buffer_dirty(bh);
612 sync_dirty_buffer(bh);
613 brelse(bh);
614 }
615
616 static void delayed_free(struct rcu_head *p)
617 {
618 struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
619 unload_nls(sbi->nls_disk);
620 unload_nls(sbi->nls_io);
621 if (sbi->options.iocharset != fat_default_iocharset)
622 kfree(sbi->options.iocharset);
623 kfree(sbi);
624 }
625
626 static void fat_put_super(struct super_block *sb)
627 {
628 struct msdos_sb_info *sbi = MSDOS_SB(sb);
629
630 fat_set_state(sb, 0, 0);
631
632 iput(sbi->fsinfo_inode);
633 iput(sbi->fat_inode);
634
635 call_rcu(&sbi->rcu, delayed_free);
636 }
637
638 static struct kmem_cache *fat_inode_cachep;
639
640 static struct inode *fat_alloc_inode(struct super_block *sb)
641 {
642 struct msdos_inode_info *ei;
643 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
644 if (!ei)
645 return NULL;
646
647 init_rwsem(&ei->truncate_lock);
648 return &ei->vfs_inode;
649 }
650
651 static void fat_i_callback(struct rcu_head *head)
652 {
653 struct inode *inode = container_of(head, struct inode, i_rcu);
654 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
655 }
656
657 static void fat_destroy_inode(struct inode *inode)
658 {
659 call_rcu(&inode->i_rcu, fat_i_callback);
660 }
661
662 static void init_once(void *foo)
663 {
664 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
665
666 spin_lock_init(&ei->cache_lru_lock);
667 ei->nr_caches = 0;
668 ei->cache_valid_id = FAT_CACHE_VALID + 1;
669 INIT_LIST_HEAD(&ei->cache_lru);
670 INIT_HLIST_NODE(&ei->i_fat_hash);
671 INIT_HLIST_NODE(&ei->i_dir_hash);
672 inode_init_once(&ei->vfs_inode);
673 }
674
675 static int __init fat_init_inodecache(void)
676 {
677 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
678 sizeof(struct msdos_inode_info),
679 0, (SLAB_RECLAIM_ACCOUNT|
680 SLAB_MEM_SPREAD),
681 init_once);
682 if (fat_inode_cachep == NULL)
683 return -ENOMEM;
684 return 0;
685 }
686
687 static void __exit fat_destroy_inodecache(void)
688 {
689 /*
690 * Make sure all delayed rcu free inodes are flushed before we
691 * destroy cache.
692 */
693 rcu_barrier();
694 kmem_cache_destroy(fat_inode_cachep);
695 }
696
697 static int fat_remount(struct super_block *sb, int *flags, char *data)
698 {
699 int new_rdonly;
700 struct msdos_sb_info *sbi = MSDOS_SB(sb);
701 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
702
703 sync_filesystem(sb);
704
705 /* make sure we update state on remount. */
706 new_rdonly = *flags & MS_RDONLY;
707 if (new_rdonly != (sb->s_flags & MS_RDONLY)) {
708 if (new_rdonly)
709 fat_set_state(sb, 0, 0);
710 else
711 fat_set_state(sb, 1, 1);
712 }
713 return 0;
714 }
715
716 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
717 {
718 struct super_block *sb = dentry->d_sb;
719 struct msdos_sb_info *sbi = MSDOS_SB(sb);
720 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
721
722 /* If the count of free cluster is still unknown, counts it here. */
723 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
724 int err = fat_count_free_clusters(dentry->d_sb);
725 if (err)
726 return err;
727 }
728
729 buf->f_type = dentry->d_sb->s_magic;
730 buf->f_bsize = sbi->cluster_size;
731 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
732 buf->f_bfree = sbi->free_clusters;
733 buf->f_bavail = sbi->free_clusters;
734 buf->f_fsid.val[0] = (u32)id;
735 buf->f_fsid.val[1] = (u32)(id >> 32);
736 buf->f_namelen =
737 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
738
739 return 0;
740 }
741
742 static int __fat_write_inode(struct inode *inode, int wait)
743 {
744 struct super_block *sb = inode->i_sb;
745 struct msdos_sb_info *sbi = MSDOS_SB(sb);
746 struct buffer_head *bh;
747 struct msdos_dir_entry *raw_entry;
748 loff_t i_pos;
749 sector_t blocknr;
750 int err, offset;
751
752 if (inode->i_ino == MSDOS_ROOT_INO)
753 return 0;
754
755 retry:
756 i_pos = fat_i_pos_read(sbi, inode);
757 if (!i_pos)
758 return 0;
759
760 fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
761 bh = sb_bread(sb, blocknr);
762 if (!bh) {
763 fat_msg(sb, KERN_ERR, "unable to read inode block "
764 "for updating (i_pos %lld)", i_pos);
765 return -EIO;
766 }
767 spin_lock(&sbi->inode_hash_lock);
768 if (i_pos != MSDOS_I(inode)->i_pos) {
769 spin_unlock(&sbi->inode_hash_lock);
770 brelse(bh);
771 goto retry;
772 }
773
774 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
775 if (S_ISDIR(inode->i_mode))
776 raw_entry->size = 0;
777 else
778 raw_entry->size = cpu_to_le32(inode->i_size);
779 raw_entry->attr = fat_make_attrs(inode);
780 fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
781 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
782 &raw_entry->date, NULL);
783 if (sbi->options.isvfat) {
784 __le16 atime;
785 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
786 &raw_entry->cdate, &raw_entry->ctime_cs);
787 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
788 &raw_entry->adate, NULL);
789 }
790 spin_unlock(&sbi->inode_hash_lock);
791 mark_buffer_dirty(bh);
792 err = 0;
793 if (wait)
794 err = sync_dirty_buffer(bh);
795 brelse(bh);
796 return err;
797 }
798
799 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
800 {
801 int err;
802
803 if (inode->i_ino == MSDOS_FSINFO_INO) {
804 struct super_block *sb = inode->i_sb;
805
806 mutex_lock(&MSDOS_SB(sb)->s_lock);
807 err = fat_clusters_flush(sb);
808 mutex_unlock(&MSDOS_SB(sb)->s_lock);
809 } else
810 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
811
812 return err;
813 }
814
815 int fat_sync_inode(struct inode *inode)
816 {
817 return __fat_write_inode(inode, 1);
818 }
819
820 EXPORT_SYMBOL_GPL(fat_sync_inode);
821
822 static int fat_show_options(struct seq_file *m, struct dentry *root);
823 static const struct super_operations fat_sops = {
824 .alloc_inode = fat_alloc_inode,
825 .destroy_inode = fat_destroy_inode,
826 .write_inode = fat_write_inode,
827 .evict_inode = fat_evict_inode,
828 .put_super = fat_put_super,
829 .statfs = fat_statfs,
830 .remount_fs = fat_remount,
831
832 .show_options = fat_show_options,
833 };
834
835 static int fat_show_options(struct seq_file *m, struct dentry *root)
836 {
837 struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
838 struct fat_mount_options *opts = &sbi->options;
839 int isvfat = opts->isvfat;
840
841 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
842 seq_printf(m, ",uid=%u",
843 from_kuid_munged(&init_user_ns, opts->fs_uid));
844 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
845 seq_printf(m, ",gid=%u",
846 from_kgid_munged(&init_user_ns, opts->fs_gid));
847 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
848 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
849 if (opts->allow_utime)
850 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
851 if (sbi->nls_disk)
852 /* strip "cp" prefix from displayed option */
853 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
854 if (isvfat) {
855 if (sbi->nls_io)
856 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
857
858 switch (opts->shortname) {
859 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
860 seq_puts(m, ",shortname=win95");
861 break;
862 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
863 seq_puts(m, ",shortname=winnt");
864 break;
865 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
866 seq_puts(m, ",shortname=mixed");
867 break;
868 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
869 seq_puts(m, ",shortname=lower");
870 break;
871 default:
872 seq_puts(m, ",shortname=unknown");
873 break;
874 }
875 }
876 if (opts->name_check != 'n')
877 seq_printf(m, ",check=%c", opts->name_check);
878 if (opts->usefree)
879 seq_puts(m, ",usefree");
880 if (opts->quiet)
881 seq_puts(m, ",quiet");
882 if (opts->showexec)
883 seq_puts(m, ",showexec");
884 if (opts->sys_immutable)
885 seq_puts(m, ",sys_immutable");
886 if (!isvfat) {
887 if (opts->dotsOK)
888 seq_puts(m, ",dotsOK=yes");
889 if (opts->nocase)
890 seq_puts(m, ",nocase");
891 } else {
892 if (opts->utf8)
893 seq_puts(m, ",utf8");
894 if (opts->unicode_xlate)
895 seq_puts(m, ",uni_xlate");
896 if (!opts->numtail)
897 seq_puts(m, ",nonumtail");
898 if (opts->rodir)
899 seq_puts(m, ",rodir");
900 }
901 if (opts->flush)
902 seq_puts(m, ",flush");
903 if (opts->tz_set) {
904 if (opts->time_offset)
905 seq_printf(m, ",time_offset=%d", opts->time_offset);
906 else
907 seq_puts(m, ",tz=UTC");
908 }
909 if (opts->errors == FAT_ERRORS_CONT)
910 seq_puts(m, ",errors=continue");
911 else if (opts->errors == FAT_ERRORS_PANIC)
912 seq_puts(m, ",errors=panic");
913 else
914 seq_puts(m, ",errors=remount-ro");
915 if (opts->nfs == FAT_NFS_NOSTALE_RO)
916 seq_puts(m, ",nfs=nostale_ro");
917 else if (opts->nfs)
918 seq_puts(m, ",nfs=stale_rw");
919 if (opts->discard)
920 seq_puts(m, ",discard");
921 if (opts->dos1xfloppy)
922 seq_puts(m, ",dos1xfloppy");
923
924 return 0;
925 }
926
927 enum {
928 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
929 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
930 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
931 Opt_immutable, Opt_dots, Opt_nodots,
932 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
933 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
934 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
935 Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
936 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
937 Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
938 };
939
940 static const match_table_t fat_tokens = {
941 {Opt_check_r, "check=relaxed"},
942 {Opt_check_s, "check=strict"},
943 {Opt_check_n, "check=normal"},
944 {Opt_check_r, "check=r"},
945 {Opt_check_s, "check=s"},
946 {Opt_check_n, "check=n"},
947 {Opt_uid, "uid=%u"},
948 {Opt_gid, "gid=%u"},
949 {Opt_umask, "umask=%o"},
950 {Opt_dmask, "dmask=%o"},
951 {Opt_fmask, "fmask=%o"},
952 {Opt_allow_utime, "allow_utime=%o"},
953 {Opt_codepage, "codepage=%u"},
954 {Opt_usefree, "usefree"},
955 {Opt_nocase, "nocase"},
956 {Opt_quiet, "quiet"},
957 {Opt_showexec, "showexec"},
958 {Opt_debug, "debug"},
959 {Opt_immutable, "sys_immutable"},
960 {Opt_flush, "flush"},
961 {Opt_tz_utc, "tz=UTC"},
962 {Opt_time_offset, "time_offset=%d"},
963 {Opt_err_cont, "errors=continue"},
964 {Opt_err_panic, "errors=panic"},
965 {Opt_err_ro, "errors=remount-ro"},
966 {Opt_discard, "discard"},
967 {Opt_nfs_stale_rw, "nfs"},
968 {Opt_nfs_stale_rw, "nfs=stale_rw"},
969 {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
970 {Opt_dos1xfloppy, "dos1xfloppy"},
971 {Opt_obsolete, "conv=binary"},
972 {Opt_obsolete, "conv=text"},
973 {Opt_obsolete, "conv=auto"},
974 {Opt_obsolete, "conv=b"},
975 {Opt_obsolete, "conv=t"},
976 {Opt_obsolete, "conv=a"},
977 {Opt_obsolete, "fat=%u"},
978 {Opt_obsolete, "blocksize=%u"},
979 {Opt_obsolete, "cvf_format=%20s"},
980 {Opt_obsolete, "cvf_options=%100s"},
981 {Opt_obsolete, "posix"},
982 {Opt_err, NULL},
983 };
984 static const match_table_t msdos_tokens = {
985 {Opt_nodots, "nodots"},
986 {Opt_nodots, "dotsOK=no"},
987 {Opt_dots, "dots"},
988 {Opt_dots, "dotsOK=yes"},
989 {Opt_err, NULL}
990 };
991 static const match_table_t vfat_tokens = {
992 {Opt_charset, "iocharset=%s"},
993 {Opt_shortname_lower, "shortname=lower"},
994 {Opt_shortname_win95, "shortname=win95"},
995 {Opt_shortname_winnt, "shortname=winnt"},
996 {Opt_shortname_mixed, "shortname=mixed"},
997 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
998 {Opt_utf8_no, "utf8=no"},
999 {Opt_utf8_no, "utf8=false"},
1000 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
1001 {Opt_utf8_yes, "utf8=yes"},
1002 {Opt_utf8_yes, "utf8=true"},
1003 {Opt_utf8_yes, "utf8"},
1004 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
1005 {Opt_uni_xl_no, "uni_xlate=no"},
1006 {Opt_uni_xl_no, "uni_xlate=false"},
1007 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
1008 {Opt_uni_xl_yes, "uni_xlate=yes"},
1009 {Opt_uni_xl_yes, "uni_xlate=true"},
1010 {Opt_uni_xl_yes, "uni_xlate"},
1011 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
1012 {Opt_nonumtail_no, "nonumtail=no"},
1013 {Opt_nonumtail_no, "nonumtail=false"},
1014 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
1015 {Opt_nonumtail_yes, "nonumtail=yes"},
1016 {Opt_nonumtail_yes, "nonumtail=true"},
1017 {Opt_nonumtail_yes, "nonumtail"},
1018 {Opt_rodir, "rodir"},
1019 {Opt_err, NULL}
1020 };
1021
1022 static int parse_options(struct super_block *sb, char *options, int is_vfat,
1023 int silent, int *debug, struct fat_mount_options *opts)
1024 {
1025 char *p;
1026 substring_t args[MAX_OPT_ARGS];
1027 int option;
1028 char *iocharset;
1029
1030 opts->isvfat = is_vfat;
1031
1032 opts->fs_uid = current_uid();
1033 opts->fs_gid = current_gid();
1034 opts->fs_fmask = opts->fs_dmask = current_umask();
1035 opts->allow_utime = -1;
1036 opts->codepage = fat_default_codepage;
1037 opts->iocharset = fat_default_iocharset;
1038 if (is_vfat) {
1039 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1040 opts->rodir = 0;
1041 } else {
1042 opts->shortname = 0;
1043 opts->rodir = 1;
1044 }
1045 opts->name_check = 'n';
1046 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
1047 opts->utf8 = opts->unicode_xlate = 0;
1048 opts->numtail = 1;
1049 opts->usefree = opts->nocase = 0;
1050 opts->tz_set = 0;
1051 opts->nfs = 0;
1052 opts->errors = FAT_ERRORS_RO;
1053 *debug = 0;
1054
1055 if (!options)
1056 goto out;
1057
1058 while ((p = strsep(&options, ",")) != NULL) {
1059 int token;
1060 if (!*p)
1061 continue;
1062
1063 token = match_token(p, fat_tokens, args);
1064 if (token == Opt_err) {
1065 if (is_vfat)
1066 token = match_token(p, vfat_tokens, args);
1067 else
1068 token = match_token(p, msdos_tokens, args);
1069 }
1070 switch (token) {
1071 case Opt_check_s:
1072 opts->name_check = 's';
1073 break;
1074 case Opt_check_r:
1075 opts->name_check = 'r';
1076 break;
1077 case Opt_check_n:
1078 opts->name_check = 'n';
1079 break;
1080 case Opt_usefree:
1081 opts->usefree = 1;
1082 break;
1083 case Opt_nocase:
1084 if (!is_vfat)
1085 opts->nocase = 1;
1086 else {
1087 /* for backward compatibility */
1088 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1089 | VFAT_SFN_CREATE_WIN95;
1090 }
1091 break;
1092 case Opt_quiet:
1093 opts->quiet = 1;
1094 break;
1095 case Opt_showexec:
1096 opts->showexec = 1;
1097 break;
1098 case Opt_debug:
1099 *debug = 1;
1100 break;
1101 case Opt_immutable:
1102 opts->sys_immutable = 1;
1103 break;
1104 case Opt_uid:
1105 if (match_int(&args[0], &option))
1106 return -EINVAL;
1107 opts->fs_uid = make_kuid(current_user_ns(), option);
1108 if (!uid_valid(opts->fs_uid))
1109 return -EINVAL;
1110 break;
1111 case Opt_gid:
1112 if (match_int(&args[0], &option))
1113 return -EINVAL;
1114 opts->fs_gid = make_kgid(current_user_ns(), option);
1115 if (!gid_valid(opts->fs_gid))
1116 return -EINVAL;
1117 break;
1118 case Opt_umask:
1119 if (match_octal(&args[0], &option))
1120 return -EINVAL;
1121 opts->fs_fmask = opts->fs_dmask = option;
1122 break;
1123 case Opt_dmask:
1124 if (match_octal(&args[0], &option))
1125 return -EINVAL;
1126 opts->fs_dmask = option;
1127 break;
1128 case Opt_fmask:
1129 if (match_octal(&args[0], &option))
1130 return -EINVAL;
1131 opts->fs_fmask = option;
1132 break;
1133 case Opt_allow_utime:
1134 if (match_octal(&args[0], &option))
1135 return -EINVAL;
1136 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1137 break;
1138 case Opt_codepage:
1139 if (match_int(&args[0], &option))
1140 return -EINVAL;
1141 opts->codepage = option;
1142 break;
1143 case Opt_flush:
1144 opts->flush = 1;
1145 break;
1146 case Opt_time_offset:
1147 if (match_int(&args[0], &option))
1148 return -EINVAL;
1149 if (option < -12 * 60 || option > 12 * 60)
1150 return -EINVAL;
1151 opts->tz_set = 1;
1152 opts->time_offset = option;
1153 break;
1154 case Opt_tz_utc:
1155 opts->tz_set = 1;
1156 opts->time_offset = 0;
1157 break;
1158 case Opt_err_cont:
1159 opts->errors = FAT_ERRORS_CONT;
1160 break;
1161 case Opt_err_panic:
1162 opts->errors = FAT_ERRORS_PANIC;
1163 break;
1164 case Opt_err_ro:
1165 opts->errors = FAT_ERRORS_RO;
1166 break;
1167 case Opt_nfs_stale_rw:
1168 opts->nfs = FAT_NFS_STALE_RW;
1169 break;
1170 case Opt_nfs_nostale_ro:
1171 opts->nfs = FAT_NFS_NOSTALE_RO;
1172 break;
1173 case Opt_dos1xfloppy:
1174 opts->dos1xfloppy = 1;
1175 break;
1176
1177 /* msdos specific */
1178 case Opt_dots:
1179 opts->dotsOK = 1;
1180 break;
1181 case Opt_nodots:
1182 opts->dotsOK = 0;
1183 break;
1184
1185 /* vfat specific */
1186 case Opt_charset:
1187 if (opts->iocharset != fat_default_iocharset)
1188 kfree(opts->iocharset);
1189 iocharset = match_strdup(&args[0]);
1190 if (!iocharset)
1191 return -ENOMEM;
1192 opts->iocharset = iocharset;
1193 break;
1194 case Opt_shortname_lower:
1195 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1196 | VFAT_SFN_CREATE_WIN95;
1197 break;
1198 case Opt_shortname_win95:
1199 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1200 | VFAT_SFN_CREATE_WIN95;
1201 break;
1202 case Opt_shortname_winnt:
1203 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1204 | VFAT_SFN_CREATE_WINNT;
1205 break;
1206 case Opt_shortname_mixed:
1207 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1208 | VFAT_SFN_CREATE_WIN95;
1209 break;
1210 case Opt_utf8_no: /* 0 or no or false */
1211 opts->utf8 = 0;
1212 break;
1213 case Opt_utf8_yes: /* empty or 1 or yes or true */
1214 opts->utf8 = 1;
1215 break;
1216 case Opt_uni_xl_no: /* 0 or no or false */
1217 opts->unicode_xlate = 0;
1218 break;
1219 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1220 opts->unicode_xlate = 1;
1221 break;
1222 case Opt_nonumtail_no: /* 0 or no or false */
1223 opts->numtail = 1; /* negated option */
1224 break;
1225 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1226 opts->numtail = 0; /* negated option */
1227 break;
1228 case Opt_rodir:
1229 opts->rodir = 1;
1230 break;
1231 case Opt_discard:
1232 opts->discard = 1;
1233 break;
1234
1235 /* obsolete mount options */
1236 case Opt_obsolete:
1237 fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1238 "not supported now", p);
1239 break;
1240 /* unknown option */
1241 default:
1242 if (!silent) {
1243 fat_msg(sb, KERN_ERR,
1244 "Unrecognized mount option \"%s\" "
1245 "or missing value", p);
1246 }
1247 return -EINVAL;
1248 }
1249 }
1250
1251 out:
1252 /* UTF-8 doesn't provide FAT semantics */
1253 if (!strcmp(opts->iocharset, "utf8")) {
1254 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1255 " for FAT filesystems, filesystem will be "
1256 "case sensitive!");
1257 }
1258
1259 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1260 if (opts->allow_utime == (unsigned short)-1)
1261 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1262 if (opts->unicode_xlate)
1263 opts->utf8 = 0;
1264 if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1265 sb->s_flags |= MS_RDONLY;
1266 sb->s_export_op = &fat_export_ops_nostale;
1267 }
1268
1269 return 0;
1270 }
1271
1272 static int fat_read_root(struct inode *inode)
1273 {
1274 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1275 int error;
1276
1277 MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1278 inode->i_uid = sbi->options.fs_uid;
1279 inode->i_gid = sbi->options.fs_gid;
1280 inode->i_version++;
1281 inode->i_generation = 0;
1282 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1283 inode->i_op = sbi->dir_ops;
1284 inode->i_fop = &fat_dir_operations;
1285 if (sbi->fat_bits == 32) {
1286 MSDOS_I(inode)->i_start = sbi->root_cluster;
1287 error = fat_calc_dir_size(inode);
1288 if (error < 0)
1289 return error;
1290 } else {
1291 MSDOS_I(inode)->i_start = 0;
1292 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1293 }
1294 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1295 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1296 MSDOS_I(inode)->i_logstart = 0;
1297 MSDOS_I(inode)->mmu_private = inode->i_size;
1298
1299 fat_save_attrs(inode, ATTR_DIR);
1300 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1301 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1302 set_nlink(inode, fat_subdirs(inode)+2);
1303
1304 return 0;
1305 }
1306
1307 static unsigned long calc_fat_clusters(struct super_block *sb)
1308 {
1309 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1310
1311 /* Divide first to avoid overflow */
1312 if (sbi->fat_bits != 12) {
1313 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1314 return ent_per_sec * sbi->fat_length;
1315 }
1316
1317 return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1318 }
1319
1320 static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1321 {
1322 if (get_unaligned_le16(&b->sector_size))
1323 return false;
1324 if (b->sec_per_clus)
1325 return false;
1326 if (b->reserved)
1327 return false;
1328 if (b->fats)
1329 return false;
1330 if (get_unaligned_le16(&b->dir_entries))
1331 return false;
1332 if (get_unaligned_le16(&b->sectors))
1333 return false;
1334 if (b->media)
1335 return false;
1336 if (b->fat_length)
1337 return false;
1338 if (b->secs_track)
1339 return false;
1340 if (b->heads)
1341 return false;
1342 return true;
1343 }
1344
1345 static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1346 int silent, struct fat_bios_param_block *bpb)
1347 {
1348 int error = -EINVAL;
1349
1350 /* Read in BPB ... */
1351 memset(bpb, 0, sizeof(*bpb));
1352 bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1353 bpb->fat_sec_per_clus = b->sec_per_clus;
1354 bpb->fat_reserved = le16_to_cpu(b->reserved);
1355 bpb->fat_fats = b->fats;
1356 bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1357 bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1358 bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1359 bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1360
1361 bpb->fat16_state = b->fat16.state;
1362 bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1363
1364 bpb->fat32_length = le32_to_cpu(b->fat32.length);
1365 bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1366 bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1367 bpb->fat32_state = b->fat32.state;
1368 bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1369
1370 /* Validate this looks like a FAT filesystem BPB */
1371 if (!bpb->fat_reserved) {
1372 if (!silent)
1373 fat_msg(sb, KERN_ERR,
1374 "bogus number of reserved sectors");
1375 goto out;
1376 }
1377 if (!bpb->fat_fats) {
1378 if (!silent)
1379 fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1380 goto out;
1381 }
1382
1383 /*
1384 * Earlier we checked here that b->secs_track and b->head are nonzero,
1385 * but it turns out valid FAT filesystems can have zero there.
1386 */
1387
1388 if (!fat_valid_media(b->media)) {
1389 if (!silent)
1390 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1391 (unsigned)b->media);
1392 goto out;
1393 }
1394
1395 if (!is_power_of_2(bpb->fat_sector_size)
1396 || (bpb->fat_sector_size < 512)
1397 || (bpb->fat_sector_size > 4096)) {
1398 if (!silent)
1399 fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1400 (unsigned)bpb->fat_sector_size);
1401 goto out;
1402 }
1403
1404 if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1405 if (!silent)
1406 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1407 (unsigned)bpb->fat_sec_per_clus);
1408 goto out;
1409 }
1410
1411 error = 0;
1412
1413 out:
1414 return error;
1415 }
1416
1417 static int fat_read_static_bpb(struct super_block *sb,
1418 struct fat_boot_sector *b, int silent,
1419 struct fat_bios_param_block *bpb)
1420 {
1421 static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1422
1423 struct fat_floppy_defaults *fdefaults = NULL;
1424 int error = -EINVAL;
1425 sector_t bd_sects;
1426 unsigned i;
1427
1428 bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE;
1429
1430 /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1431 if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1432 if (!silent)
1433 fat_msg(sb, KERN_ERR,
1434 "%s; no bootstrapping code", notdos1x);
1435 goto out;
1436 }
1437
1438 /*
1439 * If any value in this region is non-zero, it isn't archaic
1440 * DOS.
1441 */
1442 if (!fat_bpb_is_zero(b)) {
1443 if (!silent)
1444 fat_msg(sb, KERN_ERR,
1445 "%s; DOS 2.x BPB is non-zero", notdos1x);
1446 goto out;
1447 }
1448
1449 for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1450 if (floppy_defaults[i].nr_sectors == bd_sects) {
1451 fdefaults = &floppy_defaults[i];
1452 break;
1453 }
1454 }
1455
1456 if (fdefaults == NULL) {
1457 if (!silent)
1458 fat_msg(sb, KERN_WARNING,
1459 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1460 (u64)bd_sects);
1461 goto out;
1462 }
1463
1464 if (!silent)
1465 fat_msg(sb, KERN_INFO,
1466 "This looks like a DOS 1.x volume; assuming default BPB values");
1467
1468 memset(bpb, 0, sizeof(*bpb));
1469 bpb->fat_sector_size = SECTOR_SIZE;
1470 bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1471 bpb->fat_reserved = 1;
1472 bpb->fat_fats = 2;
1473 bpb->fat_dir_entries = fdefaults->dir_entries;
1474 bpb->fat_sectors = fdefaults->nr_sectors;
1475 bpb->fat_fat_length = fdefaults->fat_length;
1476
1477 error = 0;
1478
1479 out:
1480 return error;
1481 }
1482
1483 /*
1484 * Read the super block of an MS-DOS FS.
1485 */
1486 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1487 void (*setup)(struct super_block *))
1488 {
1489 struct inode *root_inode = NULL, *fat_inode = NULL;
1490 struct inode *fsinfo_inode = NULL;
1491 struct buffer_head *bh;
1492 struct fat_bios_param_block bpb;
1493 struct msdos_sb_info *sbi;
1494 u16 logical_sector_size;
1495 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1496 int debug;
1497 long error;
1498 char buf[50];
1499
1500 /*
1501 * GFP_KERNEL is ok here, because while we do hold the
1502 * supeblock lock, memory pressure can't call back into
1503 * the filesystem, since we're only just about to mount
1504 * it and have no inodes etc active!
1505 */
1506 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1507 if (!sbi)
1508 return -ENOMEM;
1509 sb->s_fs_info = sbi;
1510
1511 sb->s_flags |= MS_NODIRATIME;
1512 sb->s_magic = MSDOS_SUPER_MAGIC;
1513 sb->s_op = &fat_sops;
1514 sb->s_export_op = &fat_export_ops;
1515 mutex_init(&sbi->nfs_build_inode_lock);
1516 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1517 DEFAULT_RATELIMIT_BURST);
1518
1519 error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1520 if (error)
1521 goto out_fail;
1522
1523 setup(sb); /* flavour-specific stuff that needs options */
1524
1525 error = -EIO;
1526 sb_min_blocksize(sb, 512);
1527 bh = sb_bread(sb, 0);
1528 if (bh == NULL) {
1529 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1530 goto out_fail;
1531 }
1532
1533 error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1534 &bpb);
1535 if (error == -EINVAL && sbi->options.dos1xfloppy)
1536 error = fat_read_static_bpb(sb,
1537 (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1538 brelse(bh);
1539
1540 if (error == -EINVAL)
1541 goto out_invalid;
1542 else if (error)
1543 goto out_fail;
1544
1545 logical_sector_size = bpb.fat_sector_size;
1546 sbi->sec_per_clus = bpb.fat_sec_per_clus;
1547
1548 error = -EIO;
1549 if (logical_sector_size < sb->s_blocksize) {
1550 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1551 " (logical sector size = %u)", logical_sector_size);
1552 goto out_fail;
1553 }
1554
1555 if (logical_sector_size > sb->s_blocksize) {
1556 struct buffer_head *bh_resize;
1557
1558 if (!sb_set_blocksize(sb, logical_sector_size)) {
1559 fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1560 logical_sector_size);
1561 goto out_fail;
1562 }
1563
1564 /* Verify that the larger boot sector is fully readable */
1565 bh_resize = sb_bread(sb, 0);
1566 if (bh_resize == NULL) {
1567 fat_msg(sb, KERN_ERR, "unable to read boot sector"
1568 " (logical sector size = %lu)",
1569 sb->s_blocksize);
1570 goto out_fail;
1571 }
1572 brelse(bh_resize);
1573 }
1574
1575 mutex_init(&sbi->s_lock);
1576 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1577 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1578 sbi->fats = bpb.fat_fats;
1579 sbi->fat_bits = 0; /* Don't know yet */
1580 sbi->fat_start = bpb.fat_reserved;
1581 sbi->fat_length = bpb.fat_fat_length;
1582 sbi->root_cluster = 0;
1583 sbi->free_clusters = -1; /* Don't know yet */
1584 sbi->free_clus_valid = 0;
1585 sbi->prev_free = FAT_START_ENT;
1586 sb->s_maxbytes = 0xffffffff;
1587
1588 if (!sbi->fat_length && bpb.fat32_length) {
1589 struct fat_boot_fsinfo *fsinfo;
1590 struct buffer_head *fsinfo_bh;
1591
1592 /* Must be FAT32 */
1593 sbi->fat_bits = 32;
1594 sbi->fat_length = bpb.fat32_length;
1595 sbi->root_cluster = bpb.fat32_root_cluster;
1596
1597 /* MC - if info_sector is 0, don't multiply by 0 */
1598 sbi->fsinfo_sector = bpb.fat32_info_sector;
1599 if (sbi->fsinfo_sector == 0)
1600 sbi->fsinfo_sector = 1;
1601
1602 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1603 if (fsinfo_bh == NULL) {
1604 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1605 " (sector = %lu)", sbi->fsinfo_sector);
1606 goto out_fail;
1607 }
1608
1609 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1610 if (!IS_FSINFO(fsinfo)) {
1611 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1612 "0x%08x, 0x%08x (sector = %lu)",
1613 le32_to_cpu(fsinfo->signature1),
1614 le32_to_cpu(fsinfo->signature2),
1615 sbi->fsinfo_sector);
1616 } else {
1617 if (sbi->options.usefree)
1618 sbi->free_clus_valid = 1;
1619 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1620 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1621 }
1622
1623 brelse(fsinfo_bh);
1624 }
1625
1626 /* interpret volume ID as a little endian 32 bit integer */
1627 if (sbi->fat_bits == 32)
1628 sbi->vol_id = bpb.fat32_vol_id;
1629 else /* fat 16 or 12 */
1630 sbi->vol_id = bpb.fat16_vol_id;
1631
1632 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1633 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1634
1635 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1636 sbi->dir_entries = bpb.fat_dir_entries;
1637 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1638 if (!silent)
1639 fat_msg(sb, KERN_ERR, "bogus directory-entries per block"
1640 " (%u)", sbi->dir_entries);
1641 goto out_invalid;
1642 }
1643
1644 rootdir_sectors = sbi->dir_entries
1645 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1646 sbi->data_start = sbi->dir_start + rootdir_sectors;
1647 total_sectors = bpb.fat_sectors;
1648 if (total_sectors == 0)
1649 total_sectors = bpb.fat_total_sect;
1650
1651 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1652
1653 if (sbi->fat_bits != 32)
1654 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1655
1656 /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1657 if (sbi->fat_bits == 32)
1658 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1659 else /* fat 16 or 12 */
1660 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1661
1662 /* check that FAT table does not overflow */
1663 fat_clusters = calc_fat_clusters(sb);
1664 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1665 if (total_clusters > MAX_FAT(sb)) {
1666 if (!silent)
1667 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1668 total_clusters);
1669 goto out_invalid;
1670 }
1671
1672 sbi->max_cluster = total_clusters + FAT_START_ENT;
1673 /* check the free_clusters, it's not necessarily correct */
1674 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1675 sbi->free_clusters = -1;
1676 /* check the prev_free, it's not necessarily correct */
1677 sbi->prev_free %= sbi->max_cluster;
1678 if (sbi->prev_free < FAT_START_ENT)
1679 sbi->prev_free = FAT_START_ENT;
1680
1681 /* set up enough so that it can read an inode */
1682 fat_hash_init(sb);
1683 dir_hash_init(sb);
1684 fat_ent_access_init(sb);
1685
1686 /*
1687 * The low byte of FAT's first entry must have same value with
1688 * media-field. But in real world, too many devices is
1689 * writing wrong value. So, removed that validity check.
1690 *
1691 * if (FAT_FIRST_ENT(sb, media) != first)
1692 */
1693
1694 error = -EINVAL;
1695 sprintf(buf, "cp%d", sbi->options.codepage);
1696 sbi->nls_disk = load_nls(buf);
1697 if (!sbi->nls_disk) {
1698 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1699 goto out_fail;
1700 }
1701
1702 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1703 if (sbi->options.isvfat) {
1704 sbi->nls_io = load_nls(sbi->options.iocharset);
1705 if (!sbi->nls_io) {
1706 fat_msg(sb, KERN_ERR, "IO charset %s not found",
1707 sbi->options.iocharset);
1708 goto out_fail;
1709 }
1710 }
1711
1712 error = -ENOMEM;
1713 fat_inode = new_inode(sb);
1714 if (!fat_inode)
1715 goto out_fail;
1716 MSDOS_I(fat_inode)->i_pos = 0;
1717 sbi->fat_inode = fat_inode;
1718
1719 fsinfo_inode = new_inode(sb);
1720 if (!fsinfo_inode)
1721 goto out_fail;
1722 fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1723 sbi->fsinfo_inode = fsinfo_inode;
1724 insert_inode_hash(fsinfo_inode);
1725
1726 root_inode = new_inode(sb);
1727 if (!root_inode)
1728 goto out_fail;
1729 root_inode->i_ino = MSDOS_ROOT_INO;
1730 root_inode->i_version = 1;
1731 error = fat_read_root(root_inode);
1732 if (error < 0) {
1733 iput(root_inode);
1734 goto out_fail;
1735 }
1736 error = -ENOMEM;
1737 insert_inode_hash(root_inode);
1738 fat_attach(root_inode, 0);
1739 sb->s_root = d_make_root(root_inode);
1740 if (!sb->s_root) {
1741 fat_msg(sb, KERN_ERR, "get root inode failed");
1742 goto out_fail;
1743 }
1744
1745 if (sbi->options.discard) {
1746 struct request_queue *q = bdev_get_queue(sb->s_bdev);
1747 if (!blk_queue_discard(q))
1748 fat_msg(sb, KERN_WARNING,
1749 "mounting with \"discard\" option, but "
1750 "the device does not support discard");
1751 }
1752
1753 fat_set_state(sb, 1, 0);
1754 return 0;
1755
1756 out_invalid:
1757 error = -EINVAL;
1758 if (!silent)
1759 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1760
1761 out_fail:
1762 if (fsinfo_inode)
1763 iput(fsinfo_inode);
1764 if (fat_inode)
1765 iput(fat_inode);
1766 unload_nls(sbi->nls_io);
1767 unload_nls(sbi->nls_disk);
1768 if (sbi->options.iocharset != fat_default_iocharset)
1769 kfree(sbi->options.iocharset);
1770 sb->s_fs_info = NULL;
1771 kfree(sbi);
1772 return error;
1773 }
1774
1775 EXPORT_SYMBOL_GPL(fat_fill_super);
1776
1777 /*
1778 * helper function for fat_flush_inodes. This writes both the inode
1779 * and the file data blocks, waiting for in flight data blocks before
1780 * the start of the call. It does not wait for any io started
1781 * during the call
1782 */
1783 static int writeback_inode(struct inode *inode)
1784 {
1785
1786 int ret;
1787
1788 /* if we used wait=1, sync_inode_metadata waits for the io for the
1789 * inode to finish. So wait=0 is sent down to sync_inode_metadata
1790 * and filemap_fdatawrite is used for the data blocks
1791 */
1792 ret = sync_inode_metadata(inode, 0);
1793 if (!ret)
1794 ret = filemap_fdatawrite(inode->i_mapping);
1795 return ret;
1796 }
1797
1798 /*
1799 * write data and metadata corresponding to i1 and i2. The io is
1800 * started but we do not wait for any of it to finish.
1801 *
1802 * filemap_flush is used for the block device, so if there is a dirty
1803 * page for a block already in flight, we will not wait and start the
1804 * io over again
1805 */
1806 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1807 {
1808 int ret = 0;
1809 if (!MSDOS_SB(sb)->options.flush)
1810 return 0;
1811 if (i1)
1812 ret = writeback_inode(i1);
1813 if (!ret && i2)
1814 ret = writeback_inode(i2);
1815 if (!ret) {
1816 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1817 ret = filemap_flush(mapping);
1818 }
1819 return ret;
1820 }
1821 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1822
1823 static int __init init_fat_fs(void)
1824 {
1825 int err;
1826
1827 err = fat_cache_init();
1828 if (err)
1829 return err;
1830
1831 err = fat_init_inodecache();
1832 if (err)
1833 goto failed;
1834
1835 return 0;
1836
1837 failed:
1838 fat_cache_destroy();
1839 return err;
1840 }
1841
1842 static void __exit exit_fat_fs(void)
1843 {
1844 fat_cache_destroy();
1845 fat_destroy_inodecache();
1846 }
1847
1848 module_init(init_fat_fs)
1849 module_exit(exit_fat_fs)
1850
1851 MODULE_LICENSE("GPL");
Linux with added FPC-III support