4f818f7fa155e6407d788bf7f18b45d300a96231
[muen/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/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 <linux/iversion.h>
24 #include "fat.h"
25
26 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
27 /* if user don't select VFAT, this is undefined. */
28 #define CONFIG_FAT_DEFAULT_IOCHARSET    ""
29 #endif
30
31 #define KB_IN_SECTORS 2
32
33 /*
34  * A deserialized copy of the on-disk structure laid out in struct
35  * fat_boot_sector.
36  */
37 struct fat_bios_param_block {
38         u16     fat_sector_size;
39         u8      fat_sec_per_clus;
40         u16     fat_reserved;
41         u8      fat_fats;
42         u16     fat_dir_entries;
43         u16     fat_sectors;
44         u16     fat_fat_length;
45         u32     fat_total_sect;
46
47         u8      fat16_state;
48         u32     fat16_vol_id;
49
50         u32     fat32_length;
51         u32     fat32_root_cluster;
52         u16     fat32_info_sector;
53         u8      fat32_state;
54         u32     fat32_vol_id;
55 };
56
57 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
58 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
59
60 static struct fat_floppy_defaults {
61         unsigned nr_sectors;
62         unsigned sec_per_clus;
63         unsigned dir_entries;
64         unsigned media;
65         unsigned fat_length;
66 } floppy_defaults[] = {
67 {
68         .nr_sectors = 160 * KB_IN_SECTORS,
69         .sec_per_clus = 1,
70         .dir_entries = 64,
71         .media = 0xFE,
72         .fat_length = 1,
73 },
74 {
75         .nr_sectors = 180 * KB_IN_SECTORS,
76         .sec_per_clus = 1,
77         .dir_entries = 64,
78         .media = 0xFC,
79         .fat_length = 2,
80 },
81 {
82         .nr_sectors = 320 * KB_IN_SECTORS,
83         .sec_per_clus = 2,
84         .dir_entries = 112,
85         .media = 0xFF,
86         .fat_length = 1,
87 },
88 {
89         .nr_sectors = 360 * KB_IN_SECTORS,
90         .sec_per_clus = 2,
91         .dir_entries = 112,
92         .media = 0xFD,
93         .fat_length = 2,
94 },
95 };
96
97 int fat_add_cluster(struct inode *inode)
98 {
99         int err, cluster;
100
101         err = fat_alloc_clusters(inode, &cluster, 1);
102         if (err)
103                 return err;
104         /* FIXME: this cluster should be added after data of this
105          * cluster is writed */
106         err = fat_chain_add(inode, cluster, 1);
107         if (err)
108                 fat_free_clusters(inode, cluster);
109         return err;
110 }
111
112 static inline int __fat_get_block(struct inode *inode, sector_t iblock,
113                                   unsigned long *max_blocks,
114                                   struct buffer_head *bh_result, int create)
115 {
116         struct super_block *sb = inode->i_sb;
117         struct msdos_sb_info *sbi = MSDOS_SB(sb);
118         unsigned long mapped_blocks;
119         sector_t phys, last_block;
120         int err, offset;
121
122         err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
123         if (err)
124                 return err;
125         if (phys) {
126                 map_bh(bh_result, sb, phys);
127                 *max_blocks = min(mapped_blocks, *max_blocks);
128                 return 0;
129         }
130         if (!create)
131                 return 0;
132
133         if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
134                 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
135                         MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
136                 return -EIO;
137         }
138
139         last_block = inode->i_blocks >> (sb->s_blocksize_bits - 9);
140         offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
141         /*
142          * allocate a cluster according to the following.
143          * 1) no more available blocks
144          * 2) not part of fallocate region
145          */
146         if (!offset && !(iblock < last_block)) {
147                 /* TODO: multiple cluster allocation would be desirable. */
148                 err = fat_add_cluster(inode);
149                 if (err)
150                         return err;
151         }
152         /* available blocks on this cluster */
153         mapped_blocks = sbi->sec_per_clus - offset;
154
155         *max_blocks = min(mapped_blocks, *max_blocks);
156         MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
157
158         err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
159         if (err)
160                 return err;
161         if (!phys) {
162                 fat_fs_error(sb,
163                              "invalid FAT chain (i_pos %lld, last_block %llu)",
164                              MSDOS_I(inode)->i_pos,
165                              (unsigned long long)last_block);
166                 return -EIO;
167         }
168
169         BUG_ON(*max_blocks != mapped_blocks);
170         set_buffer_new(bh_result);
171         map_bh(bh_result, sb, phys);
172
173         return 0;
174 }
175
176 static int fat_get_block(struct inode *inode, sector_t iblock,
177                          struct buffer_head *bh_result, int create)
178 {
179         struct super_block *sb = inode->i_sb;
180         unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
181         int err;
182
183         err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
184         if (err)
185                 return err;
186         bh_result->b_size = max_blocks << sb->s_blocksize_bits;
187         return 0;
188 }
189
190 static int fat_writepage(struct page *page, struct writeback_control *wbc)
191 {
192         return block_write_full_page(page, fat_get_block, wbc);
193 }
194
195 static int fat_writepages(struct address_space *mapping,
196                           struct writeback_control *wbc)
197 {
198         return mpage_writepages(mapping, wbc, fat_get_block);
199 }
200
201 static int fat_readpage(struct file *file, struct page *page)
202 {
203         return mpage_readpage(page, fat_get_block);
204 }
205
206 static int fat_readpages(struct file *file, struct address_space *mapping,
207                          struct list_head *pages, unsigned nr_pages)
208 {
209         return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
210 }
211
212 static void fat_write_failed(struct address_space *mapping, loff_t to)
213 {
214         struct inode *inode = mapping->host;
215
216         if (to > inode->i_size) {
217                 truncate_pagecache(inode, inode->i_size);
218                 fat_truncate_blocks(inode, inode->i_size);
219         }
220 }
221
222 static int fat_write_begin(struct file *file, struct address_space *mapping,
223                         loff_t pos, unsigned len, unsigned flags,
224                         struct page **pagep, void **fsdata)
225 {
226         int err;
227
228         *pagep = NULL;
229         err = cont_write_begin(file, mapping, pos, len, flags,
230                                 pagep, fsdata, fat_get_block,
231                                 &MSDOS_I(mapping->host)->mmu_private);
232         if (err < 0)
233                 fat_write_failed(mapping, pos + len);
234         return err;
235 }
236
237 static int fat_write_end(struct file *file, struct address_space *mapping,
238                         loff_t pos, unsigned len, unsigned copied,
239                         struct page *pagep, void *fsdata)
240 {
241         struct inode *inode = mapping->host;
242         int err;
243         err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
244         if (err < len)
245                 fat_write_failed(mapping, pos + len);
246         if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
247                 inode->i_mtime = inode->i_ctime = current_time(inode);
248                 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
249                 mark_inode_dirty(inode);
250         }
251         return err;
252 }
253
254 static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
255 {
256         struct file *file = iocb->ki_filp;
257         struct address_space *mapping = file->f_mapping;
258         struct inode *inode = mapping->host;
259         size_t count = iov_iter_count(iter);
260         loff_t offset = iocb->ki_pos;
261         ssize_t ret;
262
263         if (iov_iter_rw(iter) == WRITE) {
264                 /*
265                  * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
266                  * so we need to update the ->mmu_private to block boundary.
267                  *
268                  * But we must fill the remaining area or hole by nul for
269                  * updating ->mmu_private.
270                  *
271                  * Return 0, and fallback to normal buffered write.
272                  */
273                 loff_t size = offset + count;
274                 if (MSDOS_I(inode)->mmu_private < size)
275                         return 0;
276         }
277
278         /*
279          * FAT need to use the DIO_LOCKING for avoiding the race
280          * condition of fat_get_block() and ->truncate().
281          */
282         ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
283         if (ret < 0 && iov_iter_rw(iter) == WRITE)
284                 fat_write_failed(mapping, offset + count);
285
286         return ret;
287 }
288
289 static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
290                 struct buffer_head *bh_result, int create)
291 {
292         struct super_block *sb = inode->i_sb;
293         unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
294         int err;
295         sector_t bmap;
296         unsigned long mapped_blocks;
297
298         BUG_ON(create != 0);
299
300         err = fat_bmap(inode, iblock, &bmap, &mapped_blocks, create, true);
301         if (err)
302                 return err;
303
304         if (bmap) {
305                 map_bh(bh_result, sb, bmap);
306                 max_blocks = min(mapped_blocks, max_blocks);
307         }
308
309         bh_result->b_size = max_blocks << sb->s_blocksize_bits;
310
311         return 0;
312 }
313
314 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
315 {
316         sector_t blocknr;
317
318         /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
319         down_read(&MSDOS_I(mapping->host)->truncate_lock);
320         blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
321         up_read(&MSDOS_I(mapping->host)->truncate_lock);
322
323         return blocknr;
324 }
325
326 /*
327  * fat_block_truncate_page() zeroes out a mapping from file offset `from'
328  * up to the end of the block which corresponds to `from'.
329  * This is required during truncate to physically zeroout the tail end
330  * of that block so it doesn't yield old data if the file is later grown.
331  * Also, avoid causing failure from fsx for cases of "data past EOF"
332  */
333 int fat_block_truncate_page(struct inode *inode, loff_t from)
334 {
335         return block_truncate_page(inode->i_mapping, from, fat_get_block);
336 }
337
338 static const struct address_space_operations fat_aops = {
339         .readpage       = fat_readpage,
340         .readpages      = fat_readpages,
341         .writepage      = fat_writepage,
342         .writepages     = fat_writepages,
343         .write_begin    = fat_write_begin,
344         .write_end      = fat_write_end,
345         .direct_IO      = fat_direct_IO,
346         .bmap           = _fat_bmap
347 };
348
349 /*
350  * New FAT inode stuff. We do the following:
351  *      a) i_ino is constant and has nothing with on-disk location.
352  *      b) FAT manages its own cache of directory entries.
353  *      c) *This* cache is indexed by on-disk location.
354  *      d) inode has an associated directory entry, all right, but
355  *              it may be unhashed.
356  *      e) currently entries are stored within struct inode. That should
357  *              change.
358  *      f) we deal with races in the following way:
359  *              1. readdir() and lookup() do FAT-dir-cache lookup.
360  *              2. rename() unhashes the F-d-c entry and rehashes it in
361  *                      a new place.
362  *              3. unlink() and rmdir() unhash F-d-c entry.
363  *              4. fat_write_inode() checks whether the thing is unhashed.
364  *                      If it is we silently return. If it isn't we do bread(),
365  *                      check if the location is still valid and retry if it
366  *                      isn't. Otherwise we do changes.
367  *              5. Spinlock is used to protect hash/unhash/location check/lookup
368  *              6. fat_evict_inode() unhashes the F-d-c entry.
369  *              7. lookup() and readdir() do igrab() if they find a F-d-c entry
370  *                      and consider negative result as cache miss.
371  */
372
373 static void fat_hash_init(struct super_block *sb)
374 {
375         struct msdos_sb_info *sbi = MSDOS_SB(sb);
376         int i;
377
378         spin_lock_init(&sbi->inode_hash_lock);
379         for (i = 0; i < FAT_HASH_SIZE; i++)
380                 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
381 }
382
383 static inline unsigned long fat_hash(loff_t i_pos)
384 {
385         return hash_32(i_pos, FAT_HASH_BITS);
386 }
387
388 static void dir_hash_init(struct super_block *sb)
389 {
390         struct msdos_sb_info *sbi = MSDOS_SB(sb);
391         int i;
392
393         spin_lock_init(&sbi->dir_hash_lock);
394         for (i = 0; i < FAT_HASH_SIZE; i++)
395                 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
396 }
397
398 void fat_attach(struct inode *inode, loff_t i_pos)
399 {
400         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
401
402         if (inode->i_ino != MSDOS_ROOT_INO) {
403                 struct hlist_head *head =   sbi->inode_hashtable
404                                           + fat_hash(i_pos);
405
406                 spin_lock(&sbi->inode_hash_lock);
407                 MSDOS_I(inode)->i_pos = i_pos;
408                 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
409                 spin_unlock(&sbi->inode_hash_lock);
410         }
411
412         /* If NFS support is enabled, cache the mapping of start cluster
413          * to directory inode. This is used during reconnection of
414          * dentries to the filesystem root.
415          */
416         if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
417                 struct hlist_head *d_head = sbi->dir_hashtable;
418                 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
419
420                 spin_lock(&sbi->dir_hash_lock);
421                 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
422                 spin_unlock(&sbi->dir_hash_lock);
423         }
424 }
425 EXPORT_SYMBOL_GPL(fat_attach);
426
427 void fat_detach(struct inode *inode)
428 {
429         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
430         spin_lock(&sbi->inode_hash_lock);
431         MSDOS_I(inode)->i_pos = 0;
432         hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
433         spin_unlock(&sbi->inode_hash_lock);
434
435         if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
436                 spin_lock(&sbi->dir_hash_lock);
437                 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
438                 spin_unlock(&sbi->dir_hash_lock);
439         }
440 }
441 EXPORT_SYMBOL_GPL(fat_detach);
442
443 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
444 {
445         struct msdos_sb_info *sbi = MSDOS_SB(sb);
446         struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
447         struct msdos_inode_info *i;
448         struct inode *inode = NULL;
449
450         spin_lock(&sbi->inode_hash_lock);
451         hlist_for_each_entry(i, head, i_fat_hash) {
452                 BUG_ON(i->vfs_inode.i_sb != sb);
453                 if (i->i_pos != i_pos)
454                         continue;
455                 inode = igrab(&i->vfs_inode);
456                 if (inode)
457                         break;
458         }
459         spin_unlock(&sbi->inode_hash_lock);
460         return inode;
461 }
462
463 static int is_exec(unsigned char *extension)
464 {
465         unsigned char exe_extensions[] = "EXECOMBAT", *walk;
466
467         for (walk = exe_extensions; *walk; walk += 3)
468                 if (!strncmp(extension, walk, 3))
469                         return 1;
470         return 0;
471 }
472
473 static int fat_calc_dir_size(struct inode *inode)
474 {
475         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
476         int ret, fclus, dclus;
477
478         inode->i_size = 0;
479         if (MSDOS_I(inode)->i_start == 0)
480                 return 0;
481
482         ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
483         if (ret < 0)
484                 return ret;
485         inode->i_size = (fclus + 1) << sbi->cluster_bits;
486
487         return 0;
488 }
489
490 static int fat_validate_dir(struct inode *dir)
491 {
492         struct super_block *sb = dir->i_sb;
493
494         if (dir->i_nlink < 2) {
495                 /* Directory should have "."/".." entries at least. */
496                 fat_fs_error(sb, "corrupted directory (invalid entries)");
497                 return -EIO;
498         }
499         if (MSDOS_I(dir)->i_start == 0 ||
500             MSDOS_I(dir)->i_start == MSDOS_SB(sb)->root_cluster) {
501                 /* Directory should point valid cluster. */
502                 fat_fs_error(sb, "corrupted directory (invalid i_start)");
503                 return -EIO;
504         }
505         return 0;
506 }
507
508 /* doesn't deal with root inode */
509 int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
510 {
511         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
512         int error;
513
514         MSDOS_I(inode)->i_pos = 0;
515         inode->i_uid = sbi->options.fs_uid;
516         inode->i_gid = sbi->options.fs_gid;
517         inode_inc_iversion(inode);
518         inode->i_generation = get_seconds();
519
520         if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
521                 inode->i_generation &= ~1;
522                 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
523                 inode->i_op = sbi->dir_ops;
524                 inode->i_fop = &fat_dir_operations;
525
526                 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
527                 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
528                 error = fat_calc_dir_size(inode);
529                 if (error < 0)
530                         return error;
531                 MSDOS_I(inode)->mmu_private = inode->i_size;
532
533                 set_nlink(inode, fat_subdirs(inode));
534
535                 error = fat_validate_dir(inode);
536                 if (error < 0)
537                         return error;
538         } else { /* not a directory */
539                 inode->i_generation |= 1;
540                 inode->i_mode = fat_make_mode(sbi, de->attr,
541                         ((sbi->options.showexec && !is_exec(de->name + 8))
542                          ? S_IRUGO|S_IWUGO : S_IRWXUGO));
543                 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
544
545                 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
546                 inode->i_size = le32_to_cpu(de->size);
547                 inode->i_op = &fat_file_inode_operations;
548                 inode->i_fop = &fat_file_operations;
549                 inode->i_mapping->a_ops = &fat_aops;
550                 MSDOS_I(inode)->mmu_private = inode->i_size;
551         }
552         if (de->attr & ATTR_SYS) {
553                 if (sbi->options.sys_immutable)
554                         inode->i_flags |= S_IMMUTABLE;
555         }
556         fat_save_attrs(inode, de->attr);
557
558         inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
559                            & ~((loff_t)sbi->cluster_size - 1)) >> 9;
560
561         fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
562         if (sbi->options.isvfat) {
563                 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
564                                   de->cdate, de->ctime_cs);
565                 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
566         } else
567                 inode->i_ctime = inode->i_atime = inode->i_mtime;
568
569         return 0;
570 }
571
572 static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
573 {
574         if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
575                 mutex_lock(&sbi->nfs_build_inode_lock);
576 }
577
578 static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
579 {
580         if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
581                 mutex_unlock(&sbi->nfs_build_inode_lock);
582 }
583
584 struct inode *fat_build_inode(struct super_block *sb,
585                         struct msdos_dir_entry *de, loff_t i_pos)
586 {
587         struct inode *inode;
588         int err;
589
590         fat_lock_build_inode(MSDOS_SB(sb));
591         inode = fat_iget(sb, i_pos);
592         if (inode)
593                 goto out;
594         inode = new_inode(sb);
595         if (!inode) {
596                 inode = ERR_PTR(-ENOMEM);
597                 goto out;
598         }
599         inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
600         inode_set_iversion(inode, 1);
601         err = fat_fill_inode(inode, de);
602         if (err) {
603                 iput(inode);
604                 inode = ERR_PTR(err);
605                 goto out;
606         }
607         fat_attach(inode, i_pos);
608         insert_inode_hash(inode);
609 out:
610         fat_unlock_build_inode(MSDOS_SB(sb));
611         return inode;
612 }
613
614 EXPORT_SYMBOL_GPL(fat_build_inode);
615
616 static int __fat_write_inode(struct inode *inode, int wait);
617
618 static void fat_free_eofblocks(struct inode *inode)
619 {
620         /* Release unwritten fallocated blocks on inode eviction. */
621         if ((inode->i_blocks << 9) >
622                         round_up(MSDOS_I(inode)->mmu_private,
623                                 MSDOS_SB(inode->i_sb)->cluster_size)) {
624                 int err;
625
626                 fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
627                 /* Fallocate results in updating the i_start/iogstart
628                  * for the zero byte file. So, make it return to
629                  * original state during evict and commit it to avoid
630                  * any corruption on the next access to the cluster
631                  * chain for the file.
632                  */
633                 err = __fat_write_inode(inode, inode_needs_sync(inode));
634                 if (err) {
635                         fat_msg(inode->i_sb, KERN_WARNING, "Failed to "
636                                         "update on disk inode for unused "
637                                         "fallocated blocks, inode could be "
638                                         "corrupted. Please run fsck");
639                 }
640
641         }
642 }
643
644 static void fat_evict_inode(struct inode *inode)
645 {
646         truncate_inode_pages_final(&inode->i_data);
647         if (!inode->i_nlink) {
648                 inode->i_size = 0;
649                 fat_truncate_blocks(inode, 0);
650         } else
651                 fat_free_eofblocks(inode);
652
653         invalidate_inode_buffers(inode);
654         clear_inode(inode);
655         fat_cache_inval_inode(inode);
656         fat_detach(inode);
657 }
658
659 static void fat_set_state(struct super_block *sb,
660                         unsigned int set, unsigned int force)
661 {
662         struct buffer_head *bh;
663         struct fat_boot_sector *b;
664         struct msdos_sb_info *sbi = MSDOS_SB(sb);
665
666         /* do not change any thing if mounted read only */
667         if (sb_rdonly(sb) && !force)
668                 return;
669
670         /* do not change state if fs was dirty */
671         if (sbi->dirty) {
672                 /* warn only on set (mount). */
673                 if (set)
674                         fat_msg(sb, KERN_WARNING, "Volume was not properly "
675                                 "unmounted. Some data may be corrupt. "
676                                 "Please run fsck.");
677                 return;
678         }
679
680         bh = sb_bread(sb, 0);
681         if (bh == NULL) {
682                 fat_msg(sb, KERN_ERR, "unable to read boot sector "
683                         "to mark fs as dirty");
684                 return;
685         }
686
687         b = (struct fat_boot_sector *) bh->b_data;
688
689         if (sbi->fat_bits == 32) {
690                 if (set)
691                         b->fat32.state |= FAT_STATE_DIRTY;
692                 else
693                         b->fat32.state &= ~FAT_STATE_DIRTY;
694         } else /* fat 16 and 12 */ {
695                 if (set)
696                         b->fat16.state |= FAT_STATE_DIRTY;
697                 else
698                         b->fat16.state &= ~FAT_STATE_DIRTY;
699         }
700
701         mark_buffer_dirty(bh);
702         sync_dirty_buffer(bh);
703         brelse(bh);
704 }
705
706 static void delayed_free(struct rcu_head *p)
707 {
708         struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
709         unload_nls(sbi->nls_disk);
710         unload_nls(sbi->nls_io);
711         if (sbi->options.iocharset != fat_default_iocharset)
712                 kfree(sbi->options.iocharset);
713         kfree(sbi);
714 }
715
716 static void fat_put_super(struct super_block *sb)
717 {
718         struct msdos_sb_info *sbi = MSDOS_SB(sb);
719
720         fat_set_state(sb, 0, 0);
721
722         iput(sbi->fsinfo_inode);
723         iput(sbi->fat_inode);
724
725         call_rcu(&sbi->rcu, delayed_free);
726 }
727
728 static struct kmem_cache *fat_inode_cachep;
729
730 static struct inode *fat_alloc_inode(struct super_block *sb)
731 {
732         struct msdos_inode_info *ei;
733         ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
734         if (!ei)
735                 return NULL;
736
737         init_rwsem(&ei->truncate_lock);
738         return &ei->vfs_inode;
739 }
740
741 static void fat_i_callback(struct rcu_head *head)
742 {
743         struct inode *inode = container_of(head, struct inode, i_rcu);
744         kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
745 }
746
747 static void fat_destroy_inode(struct inode *inode)
748 {
749         call_rcu(&inode->i_rcu, fat_i_callback);
750 }
751
752 static void init_once(void *foo)
753 {
754         struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
755
756         spin_lock_init(&ei->cache_lru_lock);
757         ei->nr_caches = 0;
758         ei->cache_valid_id = FAT_CACHE_VALID + 1;
759         INIT_LIST_HEAD(&ei->cache_lru);
760         INIT_HLIST_NODE(&ei->i_fat_hash);
761         INIT_HLIST_NODE(&ei->i_dir_hash);
762         inode_init_once(&ei->vfs_inode);
763 }
764
765 static int __init fat_init_inodecache(void)
766 {
767         fat_inode_cachep = kmem_cache_create("fat_inode_cache",
768                                              sizeof(struct msdos_inode_info),
769                                              0, (SLAB_RECLAIM_ACCOUNT|
770                                                 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
771                                              init_once);
772         if (fat_inode_cachep == NULL)
773                 return -ENOMEM;
774         return 0;
775 }
776
777 static void __exit fat_destroy_inodecache(void)
778 {
779         /*
780          * Make sure all delayed rcu free inodes are flushed before we
781          * destroy cache.
782          */
783         rcu_barrier();
784         kmem_cache_destroy(fat_inode_cachep);
785 }
786
787 static int fat_remount(struct super_block *sb, int *flags, char *data)
788 {
789         bool new_rdonly;
790         struct msdos_sb_info *sbi = MSDOS_SB(sb);
791         *flags |= SB_NODIRATIME | (sbi->options.isvfat ? 0 : SB_NOATIME);
792
793         sync_filesystem(sb);
794
795         /* make sure we update state on remount. */
796         new_rdonly = *flags & SB_RDONLY;
797         if (new_rdonly != sb_rdonly(sb)) {
798                 if (new_rdonly)
799                         fat_set_state(sb, 0, 0);
800                 else
801                         fat_set_state(sb, 1, 1);
802         }
803         return 0;
804 }
805
806 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
807 {
808         struct super_block *sb = dentry->d_sb;
809         struct msdos_sb_info *sbi = MSDOS_SB(sb);
810         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
811
812         /* If the count of free cluster is still unknown, counts it here. */
813         if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
814                 int err = fat_count_free_clusters(dentry->d_sb);
815                 if (err)
816                         return err;
817         }
818
819         buf->f_type = dentry->d_sb->s_magic;
820         buf->f_bsize = sbi->cluster_size;
821         buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
822         buf->f_bfree = sbi->free_clusters;
823         buf->f_bavail = sbi->free_clusters;
824         buf->f_fsid.val[0] = (u32)id;
825         buf->f_fsid.val[1] = (u32)(id >> 32);
826         buf->f_namelen =
827                 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
828
829         return 0;
830 }
831
832 static int __fat_write_inode(struct inode *inode, int wait)
833 {
834         struct super_block *sb = inode->i_sb;
835         struct msdos_sb_info *sbi = MSDOS_SB(sb);
836         struct buffer_head *bh;
837         struct msdos_dir_entry *raw_entry;
838         loff_t i_pos;
839         sector_t blocknr;
840         int err, offset;
841
842         if (inode->i_ino == MSDOS_ROOT_INO)
843                 return 0;
844
845 retry:
846         i_pos = fat_i_pos_read(sbi, inode);
847         if (!i_pos)
848                 return 0;
849
850         fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
851         bh = sb_bread(sb, blocknr);
852         if (!bh) {
853                 fat_msg(sb, KERN_ERR, "unable to read inode block "
854                        "for updating (i_pos %lld)", i_pos);
855                 return -EIO;
856         }
857         spin_lock(&sbi->inode_hash_lock);
858         if (i_pos != MSDOS_I(inode)->i_pos) {
859                 spin_unlock(&sbi->inode_hash_lock);
860                 brelse(bh);
861                 goto retry;
862         }
863
864         raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
865         if (S_ISDIR(inode->i_mode))
866                 raw_entry->size = 0;
867         else
868                 raw_entry->size = cpu_to_le32(inode->i_size);
869         raw_entry->attr = fat_make_attrs(inode);
870         fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
871         fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
872                           &raw_entry->date, NULL);
873         if (sbi->options.isvfat) {
874                 __le16 atime;
875                 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
876                                   &raw_entry->cdate, &raw_entry->ctime_cs);
877                 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
878                                   &raw_entry->adate, NULL);
879         }
880         spin_unlock(&sbi->inode_hash_lock);
881         mark_buffer_dirty(bh);
882         err = 0;
883         if (wait)
884                 err = sync_dirty_buffer(bh);
885         brelse(bh);
886         return err;
887 }
888
889 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
890 {
891         int err;
892
893         if (inode->i_ino == MSDOS_FSINFO_INO) {
894                 struct super_block *sb = inode->i_sb;
895
896                 mutex_lock(&MSDOS_SB(sb)->s_lock);
897                 err = fat_clusters_flush(sb);
898                 mutex_unlock(&MSDOS_SB(sb)->s_lock);
899         } else
900                 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
901
902         return err;
903 }
904
905 int fat_sync_inode(struct inode *inode)
906 {
907         return __fat_write_inode(inode, 1);
908 }
909
910 EXPORT_SYMBOL_GPL(fat_sync_inode);
911
912 static int fat_show_options(struct seq_file *m, struct dentry *root);
913 static const struct super_operations fat_sops = {
914         .alloc_inode    = fat_alloc_inode,
915         .destroy_inode  = fat_destroy_inode,
916         .write_inode    = fat_write_inode,
917         .evict_inode    = fat_evict_inode,
918         .put_super      = fat_put_super,
919         .statfs         = fat_statfs,
920         .remount_fs     = fat_remount,
921
922         .show_options   = fat_show_options,
923 };
924
925 static int fat_show_options(struct seq_file *m, struct dentry *root)
926 {
927         struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
928         struct fat_mount_options *opts = &sbi->options;
929         int isvfat = opts->isvfat;
930
931         if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
932                 seq_printf(m, ",uid=%u",
933                                 from_kuid_munged(&init_user_ns, opts->fs_uid));
934         if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
935                 seq_printf(m, ",gid=%u",
936                                 from_kgid_munged(&init_user_ns, opts->fs_gid));
937         seq_printf(m, ",fmask=%04o", opts->fs_fmask);
938         seq_printf(m, ",dmask=%04o", opts->fs_dmask);
939         if (opts->allow_utime)
940                 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
941         if (sbi->nls_disk)
942                 /* strip "cp" prefix from displayed option */
943                 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
944         if (isvfat) {
945                 if (sbi->nls_io)
946                         seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
947
948                 switch (opts->shortname) {
949                 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
950                         seq_puts(m, ",shortname=win95");
951                         break;
952                 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
953                         seq_puts(m, ",shortname=winnt");
954                         break;
955                 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
956                         seq_puts(m, ",shortname=mixed");
957                         break;
958                 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
959                         seq_puts(m, ",shortname=lower");
960                         break;
961                 default:
962                         seq_puts(m, ",shortname=unknown");
963                         break;
964                 }
965         }
966         if (opts->name_check != 'n')
967                 seq_printf(m, ",check=%c", opts->name_check);
968         if (opts->usefree)
969                 seq_puts(m, ",usefree");
970         if (opts->quiet)
971                 seq_puts(m, ",quiet");
972         if (opts->showexec)
973                 seq_puts(m, ",showexec");
974         if (opts->sys_immutable)
975                 seq_puts(m, ",sys_immutable");
976         if (!isvfat) {
977                 if (opts->dotsOK)
978                         seq_puts(m, ",dotsOK=yes");
979                 if (opts->nocase)
980                         seq_puts(m, ",nocase");
981         } else {
982                 if (opts->utf8)
983                         seq_puts(m, ",utf8");
984                 if (opts->unicode_xlate)
985                         seq_puts(m, ",uni_xlate");
986                 if (!opts->numtail)
987                         seq_puts(m, ",nonumtail");
988                 if (opts->rodir)
989                         seq_puts(m, ",rodir");
990         }
991         if (opts->flush)
992                 seq_puts(m, ",flush");
993         if (opts->tz_set) {
994                 if (opts->time_offset)
995                         seq_printf(m, ",time_offset=%d", opts->time_offset);
996                 else
997                         seq_puts(m, ",tz=UTC");
998         }
999         if (opts->errors == FAT_ERRORS_CONT)
1000                 seq_puts(m, ",errors=continue");
1001         else if (opts->errors == FAT_ERRORS_PANIC)
1002                 seq_puts(m, ",errors=panic");
1003         else
1004                 seq_puts(m, ",errors=remount-ro");
1005         if (opts->nfs == FAT_NFS_NOSTALE_RO)
1006                 seq_puts(m, ",nfs=nostale_ro");
1007         else if (opts->nfs)
1008                 seq_puts(m, ",nfs=stale_rw");
1009         if (opts->discard)
1010                 seq_puts(m, ",discard");
1011         if (opts->dos1xfloppy)
1012                 seq_puts(m, ",dos1xfloppy");
1013
1014         return 0;
1015 }
1016
1017 enum {
1018         Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
1019         Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
1020         Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
1021         Opt_immutable, Opt_dots, Opt_nodots,
1022         Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
1023         Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
1024         Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
1025         Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
1026         Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
1027         Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
1028 };
1029
1030 static const match_table_t fat_tokens = {
1031         {Opt_check_r, "check=relaxed"},
1032         {Opt_check_s, "check=strict"},
1033         {Opt_check_n, "check=normal"},
1034         {Opt_check_r, "check=r"},
1035         {Opt_check_s, "check=s"},
1036         {Opt_check_n, "check=n"},
1037         {Opt_uid, "uid=%u"},
1038         {Opt_gid, "gid=%u"},
1039         {Opt_umask, "umask=%o"},
1040         {Opt_dmask, "dmask=%o"},
1041         {Opt_fmask, "fmask=%o"},
1042         {Opt_allow_utime, "allow_utime=%o"},
1043         {Opt_codepage, "codepage=%u"},
1044         {Opt_usefree, "usefree"},
1045         {Opt_nocase, "nocase"},
1046         {Opt_quiet, "quiet"},
1047         {Opt_showexec, "showexec"},
1048         {Opt_debug, "debug"},
1049         {Opt_immutable, "sys_immutable"},
1050         {Opt_flush, "flush"},
1051         {Opt_tz_utc, "tz=UTC"},
1052         {Opt_time_offset, "time_offset=%d"},
1053         {Opt_err_cont, "errors=continue"},
1054         {Opt_err_panic, "errors=panic"},
1055         {Opt_err_ro, "errors=remount-ro"},
1056         {Opt_discard, "discard"},
1057         {Opt_nfs_stale_rw, "nfs"},
1058         {Opt_nfs_stale_rw, "nfs=stale_rw"},
1059         {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
1060         {Opt_dos1xfloppy, "dos1xfloppy"},
1061         {Opt_obsolete, "conv=binary"},
1062         {Opt_obsolete, "conv=text"},
1063         {Opt_obsolete, "conv=auto"},
1064         {Opt_obsolete, "conv=b"},
1065         {Opt_obsolete, "conv=t"},
1066         {Opt_obsolete, "conv=a"},
1067         {Opt_obsolete, "fat=%u"},
1068         {Opt_obsolete, "blocksize=%u"},
1069         {Opt_obsolete, "cvf_format=%20s"},
1070         {Opt_obsolete, "cvf_options=%100s"},
1071         {Opt_obsolete, "posix"},
1072         {Opt_err, NULL},
1073 };
1074 static const match_table_t msdos_tokens = {
1075         {Opt_nodots, "nodots"},
1076         {Opt_nodots, "dotsOK=no"},
1077         {Opt_dots, "dots"},
1078         {Opt_dots, "dotsOK=yes"},
1079         {Opt_err, NULL}
1080 };
1081 static const match_table_t vfat_tokens = {
1082         {Opt_charset, "iocharset=%s"},
1083         {Opt_shortname_lower, "shortname=lower"},
1084         {Opt_shortname_win95, "shortname=win95"},
1085         {Opt_shortname_winnt, "shortname=winnt"},
1086         {Opt_shortname_mixed, "shortname=mixed"},
1087         {Opt_utf8_no, "utf8=0"},                /* 0 or no or false */
1088         {Opt_utf8_no, "utf8=no"},
1089         {Opt_utf8_no, "utf8=false"},
1090         {Opt_utf8_yes, "utf8=1"},               /* empty or 1 or yes or true */
1091         {Opt_utf8_yes, "utf8=yes"},
1092         {Opt_utf8_yes, "utf8=true"},
1093         {Opt_utf8_yes, "utf8"},
1094         {Opt_uni_xl_no, "uni_xlate=0"},         /* 0 or no or false */
1095         {Opt_uni_xl_no, "uni_xlate=no"},
1096         {Opt_uni_xl_no, "uni_xlate=false"},
1097         {Opt_uni_xl_yes, "uni_xlate=1"},        /* empty or 1 or yes or true */
1098         {Opt_uni_xl_yes, "uni_xlate=yes"},
1099         {Opt_uni_xl_yes, "uni_xlate=true"},
1100         {Opt_uni_xl_yes, "uni_xlate"},
1101         {Opt_nonumtail_no, "nonumtail=0"},      /* 0 or no or false */
1102         {Opt_nonumtail_no, "nonumtail=no"},
1103         {Opt_nonumtail_no, "nonumtail=false"},
1104         {Opt_nonumtail_yes, "nonumtail=1"},     /* empty or 1 or yes or true */
1105         {Opt_nonumtail_yes, "nonumtail=yes"},
1106         {Opt_nonumtail_yes, "nonumtail=true"},
1107         {Opt_nonumtail_yes, "nonumtail"},
1108         {Opt_rodir, "rodir"},
1109         {Opt_err, NULL}
1110 };
1111
1112 static int parse_options(struct super_block *sb, char *options, int is_vfat,
1113                          int silent, int *debug, struct fat_mount_options *opts)
1114 {
1115         char *p;
1116         substring_t args[MAX_OPT_ARGS];
1117         int option;
1118         char *iocharset;
1119
1120         opts->isvfat = is_vfat;
1121
1122         opts->fs_uid = current_uid();
1123         opts->fs_gid = current_gid();
1124         opts->fs_fmask = opts->fs_dmask = current_umask();
1125         opts->allow_utime = -1;
1126         opts->codepage = fat_default_codepage;
1127         opts->iocharset = fat_default_iocharset;
1128         if (is_vfat) {
1129                 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1130                 opts->rodir = 0;
1131         } else {
1132                 opts->shortname = 0;
1133                 opts->rodir = 1;
1134         }
1135         opts->name_check = 'n';
1136         opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK =  0;
1137         opts->unicode_xlate = 0;
1138         opts->numtail = 1;
1139         opts->usefree = opts->nocase = 0;
1140         opts->tz_set = 0;
1141         opts->nfs = 0;
1142         opts->errors = FAT_ERRORS_RO;
1143         *debug = 0;
1144
1145         opts->utf8 = IS_ENABLED(CONFIG_FAT_DEFAULT_UTF8) && is_vfat;
1146
1147         if (!options)
1148                 goto out;
1149
1150         while ((p = strsep(&options, ",")) != NULL) {
1151                 int token;
1152                 if (!*p)
1153                         continue;
1154
1155                 token = match_token(p, fat_tokens, args);
1156                 if (token == Opt_err) {
1157                         if (is_vfat)
1158                                 token = match_token(p, vfat_tokens, args);
1159                         else
1160                                 token = match_token(p, msdos_tokens, args);
1161                 }
1162                 switch (token) {
1163                 case Opt_check_s:
1164                         opts->name_check = 's';
1165                         break;
1166                 case Opt_check_r:
1167                         opts->name_check = 'r';
1168                         break;
1169                 case Opt_check_n:
1170                         opts->name_check = 'n';
1171                         break;
1172                 case Opt_usefree:
1173                         opts->usefree = 1;
1174                         break;
1175                 case Opt_nocase:
1176                         if (!is_vfat)
1177                                 opts->nocase = 1;
1178                         else {
1179                                 /* for backward compatibility */
1180                                 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1181                                         | VFAT_SFN_CREATE_WIN95;
1182                         }
1183                         break;
1184                 case Opt_quiet:
1185                         opts->quiet = 1;
1186                         break;
1187                 case Opt_showexec:
1188                         opts->showexec = 1;
1189                         break;
1190                 case Opt_debug:
1191                         *debug = 1;
1192                         break;
1193                 case Opt_immutable:
1194                         opts->sys_immutable = 1;
1195                         break;
1196                 case Opt_uid:
1197                         if (match_int(&args[0], &option))
1198                                 return -EINVAL;
1199                         opts->fs_uid = make_kuid(current_user_ns(), option);
1200                         if (!uid_valid(opts->fs_uid))
1201                                 return -EINVAL;
1202                         break;
1203                 case Opt_gid:
1204                         if (match_int(&args[0], &option))
1205                                 return -EINVAL;
1206                         opts->fs_gid = make_kgid(current_user_ns(), option);
1207                         if (!gid_valid(opts->fs_gid))
1208                                 return -EINVAL;
1209                         break;
1210                 case Opt_umask:
1211                         if (match_octal(&args[0], &option))
1212                                 return -EINVAL;
1213                         opts->fs_fmask = opts->fs_dmask = option;
1214                         break;
1215                 case Opt_dmask:
1216                         if (match_octal(&args[0], &option))
1217                                 return -EINVAL;
1218                         opts->fs_dmask = option;
1219                         break;
1220                 case Opt_fmask:
1221                         if (match_octal(&args[0], &option))
1222                                 return -EINVAL;
1223                         opts->fs_fmask = option;
1224                         break;
1225                 case Opt_allow_utime:
1226                         if (match_octal(&args[0], &option))
1227                                 return -EINVAL;
1228                         opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1229                         break;
1230                 case Opt_codepage:
1231                         if (match_int(&args[0], &option))
1232                                 return -EINVAL;
1233                         opts->codepage = option;
1234                         break;
1235                 case Opt_flush:
1236                         opts->flush = 1;
1237                         break;
1238                 case Opt_time_offset:
1239                         if (match_int(&args[0], &option))
1240                                 return -EINVAL;
1241                         /*
1242                          * GMT+-12 zones may have DST corrections so at least
1243                          * 13 hours difference is needed. Make the limit 24
1244                          * just in case someone invents something unusual.
1245                          */
1246                         if (option < -24 * 60 || option > 24 * 60)
1247                                 return -EINVAL;
1248                         opts->tz_set = 1;
1249                         opts->time_offset = option;
1250                         break;
1251                 case Opt_tz_utc:
1252                         opts->tz_set = 1;
1253                         opts->time_offset = 0;
1254                         break;
1255                 case Opt_err_cont:
1256                         opts->errors = FAT_ERRORS_CONT;
1257                         break;
1258                 case Opt_err_panic:
1259                         opts->errors = FAT_ERRORS_PANIC;
1260                         break;
1261                 case Opt_err_ro:
1262                         opts->errors = FAT_ERRORS_RO;
1263                         break;
1264                 case Opt_nfs_stale_rw:
1265                         opts->nfs = FAT_NFS_STALE_RW;
1266                         break;
1267                 case Opt_nfs_nostale_ro:
1268                         opts->nfs = FAT_NFS_NOSTALE_RO;
1269                         break;
1270                 case Opt_dos1xfloppy:
1271                         opts->dos1xfloppy = 1;
1272                         break;
1273
1274                 /* msdos specific */
1275                 case Opt_dots:
1276                         opts->dotsOK = 1;
1277                         break;
1278                 case Opt_nodots:
1279                         opts->dotsOK = 0;
1280                         break;
1281
1282                 /* vfat specific */
1283                 case Opt_charset:
1284                         if (opts->iocharset != fat_default_iocharset)
1285                                 kfree(opts->iocharset);
1286                         iocharset = match_strdup(&args[0]);
1287                         if (!iocharset)
1288                                 return -ENOMEM;
1289                         opts->iocharset = iocharset;
1290                         break;
1291                 case Opt_shortname_lower:
1292                         opts->shortname = VFAT_SFN_DISPLAY_LOWER
1293                                         | VFAT_SFN_CREATE_WIN95;
1294                         break;
1295                 case Opt_shortname_win95:
1296                         opts->shortname = VFAT_SFN_DISPLAY_WIN95
1297                                         | VFAT_SFN_CREATE_WIN95;
1298                         break;
1299                 case Opt_shortname_winnt:
1300                         opts->shortname = VFAT_SFN_DISPLAY_WINNT
1301                                         | VFAT_SFN_CREATE_WINNT;
1302                         break;
1303                 case Opt_shortname_mixed:
1304                         opts->shortname = VFAT_SFN_DISPLAY_WINNT
1305                                         | VFAT_SFN_CREATE_WIN95;
1306                         break;
1307                 case Opt_utf8_no:               /* 0 or no or false */
1308                         opts->utf8 = 0;
1309                         break;
1310                 case Opt_utf8_yes:              /* empty or 1 or yes or true */
1311                         opts->utf8 = 1;
1312                         break;
1313                 case Opt_uni_xl_no:             /* 0 or no or false */
1314                         opts->unicode_xlate = 0;
1315                         break;
1316                 case Opt_uni_xl_yes:            /* empty or 1 or yes or true */
1317                         opts->unicode_xlate = 1;
1318                         break;
1319                 case Opt_nonumtail_no:          /* 0 or no or false */
1320                         opts->numtail = 1;      /* negated option */
1321                         break;
1322                 case Opt_nonumtail_yes:         /* empty or 1 or yes or true */
1323                         opts->numtail = 0;      /* negated option */
1324                         break;
1325                 case Opt_rodir:
1326                         opts->rodir = 1;
1327                         break;
1328                 case Opt_discard:
1329                         opts->discard = 1;
1330                         break;
1331
1332                 /* obsolete mount options */
1333                 case Opt_obsolete:
1334                         fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1335                                "not supported now", p);
1336                         break;
1337                 /* unknown option */
1338                 default:
1339                         if (!silent) {
1340                                 fat_msg(sb, KERN_ERR,
1341                                        "Unrecognized mount option \"%s\" "
1342                                        "or missing value", p);
1343                         }
1344                         return -EINVAL;
1345                 }
1346         }
1347
1348 out:
1349         /* UTF-8 doesn't provide FAT semantics */
1350         if (!strcmp(opts->iocharset, "utf8")) {
1351                 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1352                        " for FAT filesystems, filesystem will be "
1353                        "case sensitive!");
1354         }
1355
1356         /* If user doesn't specify allow_utime, it's initialized from dmask. */
1357         if (opts->allow_utime == (unsigned short)-1)
1358                 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1359         if (opts->unicode_xlate)
1360                 opts->utf8 = 0;
1361         if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1362                 sb->s_flags |= SB_RDONLY;
1363                 sb->s_export_op = &fat_export_ops_nostale;
1364         }
1365
1366         return 0;
1367 }
1368
1369 static void fat_dummy_inode_init(struct inode *inode)
1370 {
1371         /* Initialize this dummy inode to work as no-op. */
1372         MSDOS_I(inode)->mmu_private = 0;
1373         MSDOS_I(inode)->i_start = 0;
1374         MSDOS_I(inode)->i_logstart = 0;
1375         MSDOS_I(inode)->i_attrs = 0;
1376         MSDOS_I(inode)->i_pos = 0;
1377 }
1378
1379 static int fat_read_root(struct inode *inode)
1380 {
1381         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1382         int error;
1383
1384         MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1385         inode->i_uid = sbi->options.fs_uid;
1386         inode->i_gid = sbi->options.fs_gid;
1387         inode_inc_iversion(inode);
1388         inode->i_generation = 0;
1389         inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1390         inode->i_op = sbi->dir_ops;
1391         inode->i_fop = &fat_dir_operations;
1392         if (sbi->fat_bits == 32) {
1393                 MSDOS_I(inode)->i_start = sbi->root_cluster;
1394                 error = fat_calc_dir_size(inode);
1395                 if (error < 0)
1396                         return error;
1397         } else {
1398                 MSDOS_I(inode)->i_start = 0;
1399                 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1400         }
1401         inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1402                            & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1403         MSDOS_I(inode)->i_logstart = 0;
1404         MSDOS_I(inode)->mmu_private = inode->i_size;
1405
1406         fat_save_attrs(inode, ATTR_DIR);
1407         inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1408         inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1409         set_nlink(inode, fat_subdirs(inode)+2);
1410
1411         return 0;
1412 }
1413
1414 static unsigned long calc_fat_clusters(struct super_block *sb)
1415 {
1416         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1417
1418         /* Divide first to avoid overflow */
1419         if (sbi->fat_bits != 12) {
1420                 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1421                 return ent_per_sec * sbi->fat_length;
1422         }
1423
1424         return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1425 }
1426
1427 static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1428 {
1429         if (get_unaligned_le16(&b->sector_size))
1430                 return false;
1431         if (b->sec_per_clus)
1432                 return false;
1433         if (b->reserved)
1434                 return false;
1435         if (b->fats)
1436                 return false;
1437         if (get_unaligned_le16(&b->dir_entries))
1438                 return false;
1439         if (get_unaligned_le16(&b->sectors))
1440                 return false;
1441         if (b->media)
1442                 return false;
1443         if (b->fat_length)
1444                 return false;
1445         if (b->secs_track)
1446                 return false;
1447         if (b->heads)
1448                 return false;
1449         return true;
1450 }
1451
1452 static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1453         int silent, struct fat_bios_param_block *bpb)
1454 {
1455         int error = -EINVAL;
1456
1457         /* Read in BPB ... */
1458         memset(bpb, 0, sizeof(*bpb));
1459         bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1460         bpb->fat_sec_per_clus = b->sec_per_clus;
1461         bpb->fat_reserved = le16_to_cpu(b->reserved);
1462         bpb->fat_fats = b->fats;
1463         bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1464         bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1465         bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1466         bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1467
1468         bpb->fat16_state = b->fat16.state;
1469         bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1470
1471         bpb->fat32_length = le32_to_cpu(b->fat32.length);
1472         bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1473         bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1474         bpb->fat32_state = b->fat32.state;
1475         bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1476
1477         /* Validate this looks like a FAT filesystem BPB */
1478         if (!bpb->fat_reserved) {
1479                 if (!silent)
1480                         fat_msg(sb, KERN_ERR,
1481                                 "bogus number of reserved sectors");
1482                 goto out;
1483         }
1484         if (!bpb->fat_fats) {
1485                 if (!silent)
1486                         fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1487                 goto out;
1488         }
1489
1490         /*
1491          * Earlier we checked here that b->secs_track and b->head are nonzero,
1492          * but it turns out valid FAT filesystems can have zero there.
1493          */
1494
1495         if (!fat_valid_media(b->media)) {
1496                 if (!silent)
1497                         fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1498                                 (unsigned)b->media);
1499                 goto out;
1500         }
1501
1502         if (!is_power_of_2(bpb->fat_sector_size)
1503             || (bpb->fat_sector_size < 512)
1504             || (bpb->fat_sector_size > 4096)) {
1505                 if (!silent)
1506                         fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1507                                (unsigned)bpb->fat_sector_size);
1508                 goto out;
1509         }
1510
1511         if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1512                 if (!silent)
1513                         fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1514                                 (unsigned)bpb->fat_sec_per_clus);
1515                 goto out;
1516         }
1517
1518         error = 0;
1519
1520 out:
1521         return error;
1522 }
1523
1524 static int fat_read_static_bpb(struct super_block *sb,
1525         struct fat_boot_sector *b, int silent,
1526         struct fat_bios_param_block *bpb)
1527 {
1528         static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1529
1530         struct fat_floppy_defaults *fdefaults = NULL;
1531         int error = -EINVAL;
1532         sector_t bd_sects;
1533         unsigned i;
1534
1535         bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE;
1536
1537         /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1538         if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1539                 if (!silent)
1540                         fat_msg(sb, KERN_ERR,
1541                                 "%s; no bootstrapping code", notdos1x);
1542                 goto out;
1543         }
1544
1545         /*
1546          * If any value in this region is non-zero, it isn't archaic
1547          * DOS.
1548          */
1549         if (!fat_bpb_is_zero(b)) {
1550                 if (!silent)
1551                         fat_msg(sb, KERN_ERR,
1552                                 "%s; DOS 2.x BPB is non-zero", notdos1x);
1553                 goto out;
1554         }
1555
1556         for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1557                 if (floppy_defaults[i].nr_sectors == bd_sects) {
1558                         fdefaults = &floppy_defaults[i];
1559                         break;
1560                 }
1561         }
1562
1563         if (fdefaults == NULL) {
1564                 if (!silent)
1565                         fat_msg(sb, KERN_WARNING,
1566                                 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1567                                 (u64)bd_sects);
1568                 goto out;
1569         }
1570
1571         if (!silent)
1572                 fat_msg(sb, KERN_INFO,
1573                         "This looks like a DOS 1.x volume; assuming default BPB values");
1574
1575         memset(bpb, 0, sizeof(*bpb));
1576         bpb->fat_sector_size = SECTOR_SIZE;
1577         bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1578         bpb->fat_reserved = 1;
1579         bpb->fat_fats = 2;
1580         bpb->fat_dir_entries = fdefaults->dir_entries;
1581         bpb->fat_sectors = fdefaults->nr_sectors;
1582         bpb->fat_fat_length = fdefaults->fat_length;
1583
1584         error = 0;
1585
1586 out:
1587         return error;
1588 }
1589
1590 /*
1591  * Read the super block of an MS-DOS FS.
1592  */
1593 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1594                    void (*setup)(struct super_block *))
1595 {
1596         struct inode *root_inode = NULL, *fat_inode = NULL;
1597         struct inode *fsinfo_inode = NULL;
1598         struct buffer_head *bh;
1599         struct fat_bios_param_block bpb;
1600         struct msdos_sb_info *sbi;
1601         u16 logical_sector_size;
1602         u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1603         int debug;
1604         long error;
1605         char buf[50];
1606
1607         /*
1608          * GFP_KERNEL is ok here, because while we do hold the
1609          * superblock lock, memory pressure can't call back into
1610          * the filesystem, since we're only just about to mount
1611          * it and have no inodes etc active!
1612          */
1613         sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1614         if (!sbi)
1615                 return -ENOMEM;
1616         sb->s_fs_info = sbi;
1617
1618         sb->s_flags |= SB_NODIRATIME;
1619         sb->s_magic = MSDOS_SUPER_MAGIC;
1620         sb->s_op = &fat_sops;
1621         sb->s_export_op = &fat_export_ops;
1622         mutex_init(&sbi->nfs_build_inode_lock);
1623         ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1624                              DEFAULT_RATELIMIT_BURST);
1625
1626         error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1627         if (error)
1628                 goto out_fail;
1629
1630         setup(sb); /* flavour-specific stuff that needs options */
1631
1632         error = -EIO;
1633         sb_min_blocksize(sb, 512);
1634         bh = sb_bread(sb, 0);
1635         if (bh == NULL) {
1636                 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1637                 goto out_fail;
1638         }
1639
1640         error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1641                 &bpb);
1642         if (error == -EINVAL && sbi->options.dos1xfloppy)
1643                 error = fat_read_static_bpb(sb,
1644                         (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1645         brelse(bh);
1646
1647         if (error == -EINVAL)
1648                 goto out_invalid;
1649         else if (error)
1650                 goto out_fail;
1651
1652         logical_sector_size = bpb.fat_sector_size;
1653         sbi->sec_per_clus = bpb.fat_sec_per_clus;
1654
1655         error = -EIO;
1656         if (logical_sector_size < sb->s_blocksize) {
1657                 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1658                        " (logical sector size = %u)", logical_sector_size);
1659                 goto out_fail;
1660         }
1661
1662         if (logical_sector_size > sb->s_blocksize) {
1663                 struct buffer_head *bh_resize;
1664
1665                 if (!sb_set_blocksize(sb, logical_sector_size)) {
1666                         fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1667                                logical_sector_size);
1668                         goto out_fail;
1669                 }
1670
1671                 /* Verify that the larger boot sector is fully readable */
1672                 bh_resize = sb_bread(sb, 0);
1673                 if (bh_resize == NULL) {
1674                         fat_msg(sb, KERN_ERR, "unable to read boot sector"
1675                                " (logical sector size = %lu)",
1676                                sb->s_blocksize);
1677                         goto out_fail;
1678                 }
1679                 brelse(bh_resize);
1680         }
1681
1682         mutex_init(&sbi->s_lock);
1683         sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1684         sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1685         sbi->fats = bpb.fat_fats;
1686         sbi->fat_bits = 0;              /* Don't know yet */
1687         sbi->fat_start = bpb.fat_reserved;
1688         sbi->fat_length = bpb.fat_fat_length;
1689         sbi->root_cluster = 0;
1690         sbi->free_clusters = -1;        /* Don't know yet */
1691         sbi->free_clus_valid = 0;
1692         sbi->prev_free = FAT_START_ENT;
1693         sb->s_maxbytes = 0xffffffff;
1694
1695         if (!sbi->fat_length && bpb.fat32_length) {
1696                 struct fat_boot_fsinfo *fsinfo;
1697                 struct buffer_head *fsinfo_bh;
1698
1699                 /* Must be FAT32 */
1700                 sbi->fat_bits = 32;
1701                 sbi->fat_length = bpb.fat32_length;
1702                 sbi->root_cluster = bpb.fat32_root_cluster;
1703
1704                 /* MC - if info_sector is 0, don't multiply by 0 */
1705                 sbi->fsinfo_sector = bpb.fat32_info_sector;
1706                 if (sbi->fsinfo_sector == 0)
1707                         sbi->fsinfo_sector = 1;
1708
1709                 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1710                 if (fsinfo_bh == NULL) {
1711                         fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1712                                " (sector = %lu)", sbi->fsinfo_sector);
1713                         goto out_fail;
1714                 }
1715
1716                 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1717                 if (!IS_FSINFO(fsinfo)) {
1718                         fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1719                                "0x%08x, 0x%08x (sector = %lu)",
1720                                le32_to_cpu(fsinfo->signature1),
1721                                le32_to_cpu(fsinfo->signature2),
1722                                sbi->fsinfo_sector);
1723                 } else {
1724                         if (sbi->options.usefree)
1725                                 sbi->free_clus_valid = 1;
1726                         sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1727                         sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1728                 }
1729
1730                 brelse(fsinfo_bh);
1731         }
1732
1733         /* interpret volume ID as a little endian 32 bit integer */
1734         if (sbi->fat_bits == 32)
1735                 sbi->vol_id = bpb.fat32_vol_id;
1736         else /* fat 16 or 12 */
1737                 sbi->vol_id = bpb.fat16_vol_id;
1738
1739         sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1740         sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1741
1742         sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1743         sbi->dir_entries = bpb.fat_dir_entries;
1744         if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1745                 if (!silent)
1746                         fat_msg(sb, KERN_ERR, "bogus number of directory entries"
1747                                " (%u)", sbi->dir_entries);
1748                 goto out_invalid;
1749         }
1750
1751         rootdir_sectors = sbi->dir_entries
1752                 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1753         sbi->data_start = sbi->dir_start + rootdir_sectors;
1754         total_sectors = bpb.fat_sectors;
1755         if (total_sectors == 0)
1756                 total_sectors = bpb.fat_total_sect;
1757
1758         total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1759
1760         if (sbi->fat_bits != 32)
1761                 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1762
1763         /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1764         if (sbi->fat_bits == 32)
1765                 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1766         else /* fat 16 or 12 */
1767                 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1768
1769         /* check that FAT table does not overflow */
1770         fat_clusters = calc_fat_clusters(sb);
1771         total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1772         if (total_clusters > MAX_FAT(sb)) {
1773                 if (!silent)
1774                         fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1775                                total_clusters);
1776                 goto out_invalid;
1777         }
1778
1779         sbi->max_cluster = total_clusters + FAT_START_ENT;
1780         /* check the free_clusters, it's not necessarily correct */
1781         if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1782                 sbi->free_clusters = -1;
1783         /* check the prev_free, it's not necessarily correct */
1784         sbi->prev_free %= sbi->max_cluster;
1785         if (sbi->prev_free < FAT_START_ENT)
1786                 sbi->prev_free = FAT_START_ENT;
1787
1788         /* set up enough so that it can read an inode */
1789         fat_hash_init(sb);
1790         dir_hash_init(sb);
1791         fat_ent_access_init(sb);
1792
1793         /*
1794          * The low byte of FAT's first entry must have same value with
1795          * media-field.  But in real world, too many devices is
1796          * writing wrong value.  So, removed that validity check.
1797          *
1798          * if (FAT_FIRST_ENT(sb, media) != first)
1799          */
1800
1801         error = -EINVAL;
1802         sprintf(buf, "cp%d", sbi->options.codepage);
1803         sbi->nls_disk = load_nls(buf);
1804         if (!sbi->nls_disk) {
1805                 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1806                 goto out_fail;
1807         }
1808
1809         /* FIXME: utf8 is using iocharset for upper/lower conversion */
1810         if (sbi->options.isvfat) {
1811                 sbi->nls_io = load_nls(sbi->options.iocharset);
1812                 if (!sbi->nls_io) {
1813                         fat_msg(sb, KERN_ERR, "IO charset %s not found",
1814                                sbi->options.iocharset);
1815                         goto out_fail;
1816                 }
1817         }
1818
1819         error = -ENOMEM;
1820         fat_inode = new_inode(sb);
1821         if (!fat_inode)
1822                 goto out_fail;
1823         fat_dummy_inode_init(fat_inode);
1824         sbi->fat_inode = fat_inode;
1825
1826         fsinfo_inode = new_inode(sb);
1827         if (!fsinfo_inode)
1828                 goto out_fail;
1829         fat_dummy_inode_init(fsinfo_inode);
1830         fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1831         sbi->fsinfo_inode = fsinfo_inode;
1832         insert_inode_hash(fsinfo_inode);
1833
1834         root_inode = new_inode(sb);
1835         if (!root_inode)
1836                 goto out_fail;
1837         root_inode->i_ino = MSDOS_ROOT_INO;
1838         inode_set_iversion(root_inode, 1);
1839         error = fat_read_root(root_inode);
1840         if (error < 0) {
1841                 iput(root_inode);
1842                 goto out_fail;
1843         }
1844         error = -ENOMEM;
1845         insert_inode_hash(root_inode);
1846         fat_attach(root_inode, 0);
1847         sb->s_root = d_make_root(root_inode);
1848         if (!sb->s_root) {
1849                 fat_msg(sb, KERN_ERR, "get root inode failed");
1850                 goto out_fail;
1851         }
1852
1853         if (sbi->options.discard) {
1854                 struct request_queue *q = bdev_get_queue(sb->s_bdev);
1855                 if (!blk_queue_discard(q))
1856                         fat_msg(sb, KERN_WARNING,
1857                                         "mounting with \"discard\" option, but "
1858                                         "the device does not support discard");
1859         }
1860
1861         fat_set_state(sb, 1, 0);
1862         return 0;
1863
1864 out_invalid:
1865         error = -EINVAL;
1866         if (!silent)
1867                 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1868
1869 out_fail:
1870         if (fsinfo_inode)
1871                 iput(fsinfo_inode);
1872         if (fat_inode)
1873                 iput(fat_inode);
1874         unload_nls(sbi->nls_io);
1875         unload_nls(sbi->nls_disk);
1876         if (sbi->options.iocharset != fat_default_iocharset)
1877                 kfree(sbi->options.iocharset);
1878         sb->s_fs_info = NULL;
1879         kfree(sbi);
1880         return error;
1881 }
1882
1883 EXPORT_SYMBOL_GPL(fat_fill_super);
1884
1885 /*
1886  * helper function for fat_flush_inodes.  This writes both the inode
1887  * and the file data blocks, waiting for in flight data blocks before
1888  * the start of the call.  It does not wait for any io started
1889  * during the call
1890  */
1891 static int writeback_inode(struct inode *inode)
1892 {
1893
1894         int ret;
1895
1896         /* if we used wait=1, sync_inode_metadata waits for the io for the
1897         * inode to finish.  So wait=0 is sent down to sync_inode_metadata
1898         * and filemap_fdatawrite is used for the data blocks
1899         */
1900         ret = sync_inode_metadata(inode, 0);
1901         if (!ret)
1902                 ret = filemap_fdatawrite(inode->i_mapping);
1903         return ret;
1904 }
1905
1906 /*
1907  * write data and metadata corresponding to i1 and i2.  The io is
1908  * started but we do not wait for any of it to finish.
1909  *
1910  * filemap_flush is used for the block device, so if there is a dirty
1911  * page for a block already in flight, we will not wait and start the
1912  * io over again
1913  */
1914 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1915 {
1916         int ret = 0;
1917         if (!MSDOS_SB(sb)->options.flush)
1918                 return 0;
1919         if (i1)
1920                 ret = writeback_inode(i1);
1921         if (!ret && i2)
1922                 ret = writeback_inode(i2);
1923         if (!ret) {
1924                 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1925                 ret = filemap_flush(mapping);
1926         }
1927         return ret;
1928 }
1929 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1930
1931 static int __init init_fat_fs(void)
1932 {
1933         int err;
1934
1935         err = fat_cache_init();
1936         if (err)
1937                 return err;
1938
1939         err = fat_init_inodecache();
1940         if (err)
1941                 goto failed;
1942
1943         return 0;
1944
1945 failed:
1946         fat_cache_destroy();
1947         return err;
1948 }
1949
1950 static void __exit exit_fat_fs(void)
1951 {
1952         fat_cache_destroy();
1953         fat_destroy_inodecache();
1954 }
1955
1956 module_init(init_fat_fs)
1957 module_exit(exit_fat_fs)
1958
1959 MODULE_LICENSE("GPL");