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TOMOYO Linux Cross Reference
Linux/fs/fat/inode.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  *  linux/fs/fat/inode.c
  4  *
  5  *  Written 1992,1993 by Werner Almesberger
  6  *  VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
  7  *  Rewritten for the constant inumbers support by Al Viro
  8  *
  9  *  Fixes:
 10  *
 11  *      Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
 12  */
 13 
 14 #include <linux/module.h>
 15 #include <linux/pagemap.h>
 16 #include <linux/mpage.h>
 17 #include <linux/vfs.h>
 18 #include <linux/seq_file.h>
 19 #include <linux/parser.h>
 20 #include <linux/uio.h>
 21 #include <linux/blkdev.h>
 22 #include <linux/backing-dev.h>
 23 #include <asm/unaligned.h>
 24 #include <linux/iversion.h>
 25 #include "fat.h"
 26 
 27 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
 28 /* if user don't select VFAT, this is undefined. */
 29 #define CONFIG_FAT_DEFAULT_IOCHARSET    ""
 30 #endif
 31 
 32 #define KB_IN_SECTORS 2
 33 
 34 /* DOS dates from 1980/1/1 through 2107/12/31 */
 35 #define FAT_DATE_MIN (0<<9 | 1<<5 | 1)
 36 #define FAT_DATE_MAX (127<<9 | 12<<5 | 31)
 37 #define FAT_TIME_MAX (23<<11 | 59<<5 | 29)
 38 
 39 /*
 40  * A deserialized copy of the on-disk structure laid out in struct
 41  * fat_boot_sector.
 42  */
 43 struct fat_bios_param_block {
 44         u16     fat_sector_size;
 45         u8      fat_sec_per_clus;
 46         u16     fat_reserved;
 47         u8      fat_fats;
 48         u16     fat_dir_entries;
 49         u16     fat_sectors;
 50         u16     fat_fat_length;
 51         u32     fat_total_sect;
 52 
 53         u8      fat16_state;
 54         u32     fat16_vol_id;
 55 
 56         u32     fat32_length;
 57         u32     fat32_root_cluster;
 58         u16     fat32_info_sector;
 59         u8      fat32_state;
 60         u32     fat32_vol_id;
 61 };
 62 
 63 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
 64 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
 65 
 66 static struct fat_floppy_defaults {
 67         unsigned nr_sectors;
 68         unsigned sec_per_clus;
 69         unsigned dir_entries;
 70         unsigned media;
 71         unsigned fat_length;
 72 } floppy_defaults[] = {
 73 {
 74         .nr_sectors = 160 * KB_IN_SECTORS,
 75         .sec_per_clus = 1,
 76         .dir_entries = 64,
 77         .media = 0xFE,
 78         .fat_length = 1,
 79 },
 80 {
 81         .nr_sectors = 180 * KB_IN_SECTORS,
 82         .sec_per_clus = 1,
 83         .dir_entries = 64,
 84         .media = 0xFC,
 85         .fat_length = 2,
 86 },
 87 {
 88         .nr_sectors = 320 * KB_IN_SECTORS,
 89         .sec_per_clus = 2,
 90         .dir_entries = 112,
 91         .media = 0xFF,
 92         .fat_length = 1,
 93 },
 94 {
 95         .nr_sectors = 360 * KB_IN_SECTORS,
 96         .sec_per_clus = 2,
 97         .dir_entries = 112,
 98         .media = 0xFD,
 99         .fat_length = 2,
100 },
101 };
102 
103 int fat_add_cluster(struct inode *inode)
104 {
105         int err, cluster;
106 
107         err = fat_alloc_clusters(inode, &cluster, 1);
108         if (err)
109                 return err;
110         /* FIXME: this cluster should be added after data of this
111          * cluster is writed */
112         err = fat_chain_add(inode, cluster, 1);
113         if (err)
114                 fat_free_clusters(inode, cluster);
115         return err;
116 }
117 
118 static inline int __fat_get_block(struct inode *inode, sector_t iblock,
119                                   unsigned long *max_blocks,
120                                   struct buffer_head *bh_result, int create)
121 {
122         struct super_block *sb = inode->i_sb;
123         struct msdos_sb_info *sbi = MSDOS_SB(sb);
124         unsigned long mapped_blocks;
125         sector_t phys, last_block;
126         int err, offset;
127 
128         err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
129         if (err)
130                 return err;
131         if (phys) {
132                 map_bh(bh_result, sb, phys);
133                 *max_blocks = min(mapped_blocks, *max_blocks);
134                 return 0;
135         }
136         if (!create)
137                 return 0;
138 
139         if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
140                 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
141                         MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
142                 return -EIO;
143         }
144 
145         last_block = inode->i_blocks >> (sb->s_blocksize_bits - 9);
146         offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
147         /*
148          * allocate a cluster according to the following.
149          * 1) no more available blocks
150          * 2) not part of fallocate region
151          */
152         if (!offset && !(iblock < last_block)) {
153                 /* TODO: multiple cluster allocation would be desirable. */
154                 err = fat_add_cluster(inode);
155                 if (err)
156                         return err;
157         }
158         /* available blocks on this cluster */
159         mapped_blocks = sbi->sec_per_clus - offset;
160 
161         *max_blocks = min(mapped_blocks, *max_blocks);
162         MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
163 
164         err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
165         if (err)
166                 return err;
167         if (!phys) {
168                 fat_fs_error(sb,
169                              "invalid FAT chain (i_pos %lld, last_block %llu)",
170                              MSDOS_I(inode)->i_pos,
171                              (unsigned long long)last_block);
172                 return -EIO;
173         }
174 
175         BUG_ON(*max_blocks != mapped_blocks);
176         set_buffer_new(bh_result);
177         map_bh(bh_result, sb, phys);
178 
179         return 0;
180 }
181 
182 static int fat_get_block(struct inode *inode, sector_t iblock,
183                          struct buffer_head *bh_result, int create)
184 {
185         struct super_block *sb = inode->i_sb;
186         unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
187         int err;
188 
189         err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
190         if (err)
191                 return err;
192         bh_result->b_size = max_blocks << sb->s_blocksize_bits;
193         return 0;
194 }
195 
196 static int fat_writepage(struct page *page, struct writeback_control *wbc)
197 {
198         return block_write_full_page(page, fat_get_block, wbc);
199 }
200 
201 static int fat_writepages(struct address_space *mapping,
202                           struct writeback_control *wbc)
203 {
204         return mpage_writepages(mapping, wbc, fat_get_block);
205 }
206 
207 static int fat_readpage(struct file *file, struct page *page)
208 {
209         return mpage_readpage(page, fat_get_block);
210 }
211 
212 static int fat_readpages(struct file *file, struct address_space *mapping,
213                          struct list_head *pages, unsigned nr_pages)
214 {
215         return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
216 }
217 
218 static void fat_write_failed(struct address_space *mapping, loff_t to)
219 {
220         struct inode *inode = mapping->host;
221 
222         if (to > inode->i_size) {
223                 truncate_pagecache(inode, inode->i_size);
224                 fat_truncate_blocks(inode, inode->i_size);
225         }
226 }
227 
228 static int fat_write_begin(struct file *file, struct address_space *mapping,
229                         loff_t pos, unsigned len, unsigned flags,
230                         struct page **pagep, void **fsdata)
231 {
232         int err;
233 
234         *pagep = NULL;
235         err = cont_write_begin(file, mapping, pos, len, flags,
236                                 pagep, fsdata, fat_get_block,
237                                 &MSDOS_I(mapping->host)->mmu_private);
238         if (err < 0)
239                 fat_write_failed(mapping, pos + len);
240         return err;
241 }
242 
243 static int fat_write_end(struct file *file, struct address_space *mapping,
244                         loff_t pos, unsigned len, unsigned copied,
245                         struct page *pagep, void *fsdata)
246 {
247         struct inode *inode = mapping->host;
248         int err;
249         err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
250         if (err < len)
251                 fat_write_failed(mapping, pos + len);
252         if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
253                 fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
254                 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
255                 mark_inode_dirty(inode);
256         }
257         return err;
258 }
259 
260 static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
261 {
262         struct file *file = iocb->ki_filp;
263         struct address_space *mapping = file->f_mapping;
264         struct inode *inode = mapping->host;
265         size_t count = iov_iter_count(iter);
266         loff_t offset = iocb->ki_pos;
267         ssize_t ret;
268 
269         if (iov_iter_rw(iter) == WRITE) {
270                 /*
271                  * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
272                  * so we need to update the ->mmu_private to block boundary.
273                  *
274                  * But we must fill the remaining area or hole by nul for
275                  * updating ->mmu_private.
276                  *
277                  * Return 0, and fallback to normal buffered write.
278                  */
279                 loff_t size = offset + count;
280                 if (MSDOS_I(inode)->mmu_private < size)
281                         return 0;
282         }
283 
284         /*
285          * FAT need to use the DIO_LOCKING for avoiding the race
286          * condition of fat_get_block() and ->truncate().
287          */
288         ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
289         if (ret < 0 && iov_iter_rw(iter) == WRITE)
290                 fat_write_failed(mapping, offset + count);
291 
292         return ret;
293 }
294 
295 static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
296                 struct buffer_head *bh_result, int create)
297 {
298         struct super_block *sb = inode->i_sb;
299         unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
300         int err;
301         sector_t bmap;
302         unsigned long mapped_blocks;
303 
304         BUG_ON(create != 0);
305 
306         err = fat_bmap(inode, iblock, &bmap, &mapped_blocks, create, true);
307         if (err)
308                 return err;
309 
310         if (bmap) {
311                 map_bh(bh_result, sb, bmap);
312                 max_blocks = min(mapped_blocks, max_blocks);
313         }
314 
315         bh_result->b_size = max_blocks << sb->s_blocksize_bits;
316 
317         return 0;
318 }
319 
320 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
321 {
322         sector_t blocknr;
323 
324         /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
325         down_read(&MSDOS_I(mapping->host)->truncate_lock);
326         blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
327         up_read(&MSDOS_I(mapping->host)->truncate_lock);
328 
329         return blocknr;
330 }
331 
332 /*
333  * fat_block_truncate_page() zeroes out a mapping from file offset `from'
334  * up to the end of the block which corresponds to `from'.
335  * This is required during truncate to physically zeroout the tail end
336  * of that block so it doesn't yield old data if the file is later grown.
337  * Also, avoid causing failure from fsx for cases of "data past EOF"
338  */
339 int fat_block_truncate_page(struct inode *inode, loff_t from)
340 {
341         return block_truncate_page(inode->i_mapping, from, fat_get_block);
342 }
343 
344 static const struct address_space_operations fat_aops = {
345         .readpage       = fat_readpage,
346         .readpages      = fat_readpages,
347         .writepage      = fat_writepage,
348         .writepages     = fat_writepages,
349         .write_begin    = fat_write_begin,
350         .write_end      = fat_write_end,
351         .direct_IO      = fat_direct_IO,
352         .bmap           = _fat_bmap
353 };
354 
355 /*
356  * New FAT inode stuff. We do the following:
357  *      a) i_ino is constant and has nothing with on-disk location.
358  *      b) FAT manages its own cache of directory entries.
359  *      c) *This* cache is indexed by on-disk location.
360  *      d) inode has an associated directory entry, all right, but
361  *              it may be unhashed.
362  *      e) currently entries are stored within struct inode. That should
363  *              change.
364  *      f) we deal with races in the following way:
365  *              1. readdir() and lookup() do FAT-dir-cache lookup.
366  *              2. rename() unhashes the F-d-c entry and rehashes it in
367  *                      a new place.
368  *              3. unlink() and rmdir() unhash F-d-c entry.
369  *              4. fat_write_inode() checks whether the thing is unhashed.
370  *                      If it is we silently return. If it isn't we do bread(),
371  *                      check if the location is still valid and retry if it
372  *                      isn't. Otherwise we do changes.
373  *              5. Spinlock is used to protect hash/unhash/location check/lookup
374  *              6. fat_evict_inode() unhashes the F-d-c entry.
375  *              7. lookup() and readdir() do igrab() if they find a F-d-c entry
376  *                      and consider negative result as cache miss.
377  */
378 
379 static void fat_hash_init(struct super_block *sb)
380 {
381         struct msdos_sb_info *sbi = MSDOS_SB(sb);
382         int i;
383 
384         spin_lock_init(&sbi->inode_hash_lock);
385         for (i = 0; i < FAT_HASH_SIZE; i++)
386                 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
387 }
388 
389 static inline unsigned long fat_hash(loff_t i_pos)
390 {
391         return hash_32(i_pos, FAT_HASH_BITS);
392 }
393 
394 static void dir_hash_init(struct super_block *sb)
395 {
396         struct msdos_sb_info *sbi = MSDOS_SB(sb);
397         int i;
398 
399         spin_lock_init(&sbi->dir_hash_lock);
400         for (i = 0; i < FAT_HASH_SIZE; i++)
401                 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
402 }
403 
404 void fat_attach(struct inode *inode, loff_t i_pos)
405 {
406         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
407 
408         if (inode->i_ino != MSDOS_ROOT_INO) {
409                 struct hlist_head *head =   sbi->inode_hashtable
410                                           + fat_hash(i_pos);
411 
412                 spin_lock(&sbi->inode_hash_lock);
413                 MSDOS_I(inode)->i_pos = i_pos;
414                 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
415                 spin_unlock(&sbi->inode_hash_lock);
416         }
417 
418         /* If NFS support is enabled, cache the mapping of start cluster
419          * to directory inode. This is used during reconnection of
420          * dentries to the filesystem root.
421          */
422         if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
423                 struct hlist_head *d_head = sbi->dir_hashtable;
424                 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
425 
426                 spin_lock(&sbi->dir_hash_lock);
427                 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
428                 spin_unlock(&sbi->dir_hash_lock);
429         }
430 }
431 EXPORT_SYMBOL_GPL(fat_attach);
432 
433 void fat_detach(struct inode *inode)
434 {
435         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
436         spin_lock(&sbi->inode_hash_lock);
437         MSDOS_I(inode)->i_pos = 0;
438         hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
439         spin_unlock(&sbi->inode_hash_lock);
440 
441         if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
442                 spin_lock(&sbi->dir_hash_lock);
443                 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
444                 spin_unlock(&sbi->dir_hash_lock);
445         }
446 }
447 EXPORT_SYMBOL_GPL(fat_detach);
448 
449 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
450 {
451         struct msdos_sb_info *sbi = MSDOS_SB(sb);
452         struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
453         struct msdos_inode_info *i;
454         struct inode *inode = NULL;
455 
456         spin_lock(&sbi->inode_hash_lock);
457         hlist_for_each_entry(i, head, i_fat_hash) {
458                 BUG_ON(i->vfs_inode.i_sb != sb);
459                 if (i->i_pos != i_pos)
460                         continue;
461                 inode = igrab(&i->vfs_inode);
462                 if (inode)
463                         break;
464         }
465         spin_unlock(&sbi->inode_hash_lock);
466         return inode;
467 }
468 
469 static int is_exec(unsigned char *extension)
470 {
471         unsigned char exe_extensions[] = "EXECOMBAT", *walk;
472 
473         for (walk = exe_extensions; *walk; walk += 3)
474                 if (!strncmp(extension, walk, 3))
475                         return 1;
476         return 0;
477 }
478 
479 static int fat_calc_dir_size(struct inode *inode)
480 {
481         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
482         int ret, fclus, dclus;
483 
484         inode->i_size = 0;
485         if (MSDOS_I(inode)->i_start == 0)
486                 return 0;
487 
488         ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
489         if (ret < 0)
490                 return ret;
491         inode->i_size = (fclus + 1) << sbi->cluster_bits;
492 
493         return 0;
494 }
495 
496 static int fat_validate_dir(struct inode *dir)
497 {
498         struct super_block *sb = dir->i_sb;
499 
500         if (dir->i_nlink < 2) {
501                 /* Directory should have "."/".." entries at least. */
502                 fat_fs_error(sb, "corrupted directory (invalid entries)");
503                 return -EIO;
504         }
505         if (MSDOS_I(dir)->i_start == 0 ||
506             MSDOS_I(dir)->i_start == MSDOS_SB(sb)->root_cluster) {
507                 /* Directory should point valid cluster. */
508                 fat_fs_error(sb, "corrupted directory (invalid i_start)");
509                 return -EIO;
510         }
511         return 0;
512 }
513 
514 /* doesn't deal with root inode */
515 int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
516 {
517         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
518         int error;
519 
520         MSDOS_I(inode)->i_pos = 0;
521         inode->i_uid = sbi->options.fs_uid;
522         inode->i_gid = sbi->options.fs_gid;
523         inode_inc_iversion(inode);
524         inode->i_generation = get_seconds();
525 
526         if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
527                 inode->i_generation &= ~1;
528                 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
529                 inode->i_op = sbi->dir_ops;
530                 inode->i_fop = &fat_dir_operations;
531 
532                 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
533                 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
534                 error = fat_calc_dir_size(inode);
535                 if (error < 0)
536                         return error;
537                 MSDOS_I(inode)->mmu_private = inode->i_size;
538 
539                 set_nlink(inode, fat_subdirs(inode));
540 
541                 error = fat_validate_dir(inode);
542                 if (error < 0)
543                         return error;
544         } else { /* not a directory */
545                 inode->i_generation |= 1;
546                 inode->i_mode = fat_make_mode(sbi, de->attr,
547                         ((sbi->options.showexec && !is_exec(de->name + 8))
548                          ? S_IRUGO|S_IWUGO : S_IRWXUGO));
549                 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
550 
551                 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
552                 inode->i_size = le32_to_cpu(de->size);
553                 inode->i_op = &fat_file_inode_operations;
554                 inode->i_fop = &fat_file_operations;
555                 inode->i_mapping->a_ops = &fat_aops;
556                 MSDOS_I(inode)->mmu_private = inode->i_size;
557         }
558         if (de->attr & ATTR_SYS) {
559                 if (sbi->options.sys_immutable)
560                         inode->i_flags |= S_IMMUTABLE;
561         }
562         fat_save_attrs(inode, de->attr);
563 
564         inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
565                            & ~((loff_t)sbi->cluster_size - 1)) >> 9;
566 
567         fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
568         if (sbi->options.isvfat) {
569                 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
570                                   de->cdate, de->ctime_cs);
571                 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
572         } else
573                 fat_truncate_time(inode, &inode->i_mtime, S_ATIME|S_CTIME);
574 
575         return 0;
576 }
577 
578 static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
579 {
580         if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
581                 mutex_lock(&sbi->nfs_build_inode_lock);
582 }
583 
584 static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
585 {
586         if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
587                 mutex_unlock(&sbi->nfs_build_inode_lock);
588 }
589 
590 struct inode *fat_build_inode(struct super_block *sb,
591                         struct msdos_dir_entry *de, loff_t i_pos)
592 {
593         struct inode *inode;
594         int err;
595 
596         fat_lock_build_inode(MSDOS_SB(sb));
597         inode = fat_iget(sb, i_pos);
598         if (inode)
599                 goto out;
600         inode = new_inode(sb);
601         if (!inode) {
602                 inode = ERR_PTR(-ENOMEM);
603                 goto out;
604         }
605         inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
606         inode_set_iversion(inode, 1);
607         err = fat_fill_inode(inode, de);
608         if (err) {
609                 iput(inode);
610                 inode = ERR_PTR(err);
611                 goto out;
612         }
613         fat_attach(inode, i_pos);
614         insert_inode_hash(inode);
615 out:
616         fat_unlock_build_inode(MSDOS_SB(sb));
617         return inode;
618 }
619 
620 EXPORT_SYMBOL_GPL(fat_build_inode);
621 
622 static int __fat_write_inode(struct inode *inode, int wait);
623 
624 static void fat_free_eofblocks(struct inode *inode)
625 {
626         /* Release unwritten fallocated blocks on inode eviction. */
627         if ((inode->i_blocks << 9) >
628                         round_up(MSDOS_I(inode)->mmu_private,
629                                 MSDOS_SB(inode->i_sb)->cluster_size)) {
630                 int err;
631 
632                 fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
633                 /* Fallocate results in updating the i_start/iogstart
634                  * for the zero byte file. So, make it return to
635                  * original state during evict and commit it to avoid
636                  * any corruption on the next access to the cluster
637                  * chain for the file.
638                  */
639                 err = __fat_write_inode(inode, inode_needs_sync(inode));
640                 if (err) {
641                         fat_msg(inode->i_sb, KERN_WARNING, "Failed to "
642                                         "update on disk inode for unused "
643                                         "fallocated blocks, inode could be "
644                                         "corrupted. Please run fsck");
645                 }
646 
647         }
648 }
649 
650 static void fat_evict_inode(struct inode *inode)
651 {
652         truncate_inode_pages_final(&inode->i_data);
653         if (!inode->i_nlink) {
654                 inode->i_size = 0;
655                 fat_truncate_blocks(inode, 0);
656         } else
657                 fat_free_eofblocks(inode);
658 
659         invalidate_inode_buffers(inode);
660         clear_inode(inode);
661         fat_cache_inval_inode(inode);
662         fat_detach(inode);
663 }
664 
665 static void fat_set_state(struct super_block *sb,
666                         unsigned int set, unsigned int force)
667 {
668         struct buffer_head *bh;
669         struct fat_boot_sector *b;
670         struct msdos_sb_info *sbi = MSDOS_SB(sb);
671 
672         /* do not change any thing if mounted read only */
673         if (sb_rdonly(sb) && !force)
674                 return;
675 
676         /* do not change state if fs was dirty */
677         if (sbi->dirty) {
678                 /* warn only on set (mount). */
679                 if (set)
680                         fat_msg(sb, KERN_WARNING, "Volume was not properly "
681                                 "unmounted. Some data may be corrupt. "
682                                 "Please run fsck.");
683                 return;
684         }
685 
686         bh = sb_bread(sb, 0);
687         if (bh == NULL) {
688                 fat_msg(sb, KERN_ERR, "unable to read boot sector "
689                         "to mark fs as dirty");
690                 return;
691         }
692 
693         b = (struct fat_boot_sector *) bh->b_data;
694 
695         if (is_fat32(sbi)) {
696                 if (set)
697                         b->fat32.state |= FAT_STATE_DIRTY;
698                 else
699                         b->fat32.state &= ~FAT_STATE_DIRTY;
700         } else /* fat 16 and 12 */ {
701                 if (set)
702                         b->fat16.state |= FAT_STATE_DIRTY;
703                 else
704                         b->fat16.state &= ~FAT_STATE_DIRTY;
705         }
706 
707         mark_buffer_dirty(bh);
708         sync_dirty_buffer(bh);
709         brelse(bh);
710 }
711 
712 static void fat_reset_iocharset(struct fat_mount_options *opts)
713 {
714         if (opts->iocharset != fat_default_iocharset) {
715                 /* Note: opts->iocharset can be NULL here */
716                 kfree(opts->iocharset);
717                 opts->iocharset = fat_default_iocharset;
718         }
719 }
720 
721 static void delayed_free(struct rcu_head *p)
722 {
723         struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
724         unload_nls(sbi->nls_disk);
725         unload_nls(sbi->nls_io);
726         fat_reset_iocharset(&sbi->options);
727         kfree(sbi);
728 }
729 
730 static void fat_put_super(struct super_block *sb)
731 {
732         struct msdos_sb_info *sbi = MSDOS_SB(sb);
733 
734         fat_set_state(sb, 0, 0);
735 
736         iput(sbi->fsinfo_inode);
737         iput(sbi->fat_inode);
738 
739         call_rcu(&sbi->rcu, delayed_free);
740 }
741 
742 static struct kmem_cache *fat_inode_cachep;
743 
744 static struct inode *fat_alloc_inode(struct super_block *sb)
745 {
746         struct msdos_inode_info *ei;
747         ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
748         if (!ei)
749                 return NULL;
750 
751         init_rwsem(&ei->truncate_lock);
752         /* Zeroing to allow iput() even if partial initialized inode. */
753         ei->mmu_private = 0;
754         ei->i_start = 0;
755         ei->i_logstart = 0;
756         ei->i_attrs = 0;
757         ei->i_pos = 0;
758 
759         return &ei->vfs_inode;
760 }
761 
762 static void fat_free_inode(struct inode *inode)
763 {
764         kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
765 }
766 
767 static void init_once(void *foo)
768 {
769         struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
770 
771         spin_lock_init(&ei->cache_lru_lock);
772         ei->nr_caches = 0;
773         ei->cache_valid_id = FAT_CACHE_VALID + 1;
774         INIT_LIST_HEAD(&ei->cache_lru);
775         INIT_HLIST_NODE(&ei->i_fat_hash);
776         INIT_HLIST_NODE(&ei->i_dir_hash);
777         inode_init_once(&ei->vfs_inode);
778 }
779 
780 static int __init fat_init_inodecache(void)
781 {
782         fat_inode_cachep = kmem_cache_create("fat_inode_cache",
783                                              sizeof(struct msdos_inode_info),
784                                              0, (SLAB_RECLAIM_ACCOUNT|
785                                                 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
786                                              init_once);
787         if (fat_inode_cachep == NULL)
788                 return -ENOMEM;
789         return 0;
790 }
791 
792 static void __exit fat_destroy_inodecache(void)
793 {
794         /*
795          * Make sure all delayed rcu free inodes are flushed before we
796          * destroy cache.
797          */
798         rcu_barrier();
799         kmem_cache_destroy(fat_inode_cachep);
800 }
801 
802 static int fat_remount(struct super_block *sb, int *flags, char *data)
803 {
804         bool new_rdonly;
805         struct msdos_sb_info *sbi = MSDOS_SB(sb);
806         *flags |= SB_NODIRATIME | (sbi->options.isvfat ? 0 : SB_NOATIME);
807 
808         sync_filesystem(sb);
809 
810         /* make sure we update state on remount. */
811         new_rdonly = *flags & SB_RDONLY;
812         if (new_rdonly != sb_rdonly(sb)) {
813                 if (new_rdonly)
814                         fat_set_state(sb, 0, 0);
815                 else
816                         fat_set_state(sb, 1, 1);
817         }
818         return 0;
819 }
820 
821 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
822 {
823         struct super_block *sb = dentry->d_sb;
824         struct msdos_sb_info *sbi = MSDOS_SB(sb);
825         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
826 
827         /* If the count of free cluster is still unknown, counts it here. */
828         if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
829                 int err = fat_count_free_clusters(dentry->d_sb);
830                 if (err)
831                         return err;
832         }
833 
834         buf->f_type = dentry->d_sb->s_magic;
835         buf->f_bsize = sbi->cluster_size;
836         buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
837         buf->f_bfree = sbi->free_clusters;
838         buf->f_bavail = sbi->free_clusters;
839         buf->f_fsid.val[0] = (u32)id;
840         buf->f_fsid.val[1] = (u32)(id >> 32);
841         buf->f_namelen =
842                 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
843 
844         return 0;
845 }
846 
847 static int __fat_write_inode(struct inode *inode, int wait)
848 {
849         struct super_block *sb = inode->i_sb;
850         struct msdos_sb_info *sbi = MSDOS_SB(sb);
851         struct buffer_head *bh;
852         struct msdos_dir_entry *raw_entry;
853         loff_t i_pos;
854         sector_t blocknr;
855         int err, offset;
856 
857         if (inode->i_ino == MSDOS_ROOT_INO)
858                 return 0;
859 
860 retry:
861         i_pos = fat_i_pos_read(sbi, inode);
862         if (!i_pos)
863                 return 0;
864 
865         fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
866         bh = sb_bread(sb, blocknr);
867         if (!bh) {
868                 fat_msg(sb, KERN_ERR, "unable to read inode block "
869                        "for updating (i_pos %lld)", i_pos);
870                 return -EIO;
871         }
872         spin_lock(&sbi->inode_hash_lock);
873         if (i_pos != MSDOS_I(inode)->i_pos) {
874                 spin_unlock(&sbi->inode_hash_lock);
875                 brelse(bh);
876                 goto retry;
877         }
878 
879         raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
880         if (S_ISDIR(inode->i_mode))
881                 raw_entry->size = 0;
882         else
883                 raw_entry->size = cpu_to_le32(inode->i_size);
884         raw_entry->attr = fat_make_attrs(inode);
885         fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
886         fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
887                           &raw_entry->date, NULL);
888         if (sbi->options.isvfat) {
889                 __le16 atime;
890                 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
891                                   &raw_entry->cdate, &raw_entry->ctime_cs);
892                 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
893                                   &raw_entry->adate, NULL);
894         }
895         spin_unlock(&sbi->inode_hash_lock);
896         mark_buffer_dirty(bh);
897         err = 0;
898         if (wait)
899                 err = sync_dirty_buffer(bh);
900         brelse(bh);
901         return err;
902 }
903 
904 static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
905 {
906         int err;
907 
908         if (inode->i_ino == MSDOS_FSINFO_INO) {
909                 struct super_block *sb = inode->i_sb;
910 
911                 mutex_lock(&MSDOS_SB(sb)->s_lock);
912                 err = fat_clusters_flush(sb);
913                 mutex_unlock(&MSDOS_SB(sb)->s_lock);
914         } else
915                 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
916 
917         return err;
918 }
919 
920 int fat_sync_inode(struct inode *inode)
921 {
922         return __fat_write_inode(inode, 1);
923 }
924 
925 EXPORT_SYMBOL_GPL(fat_sync_inode);
926 
927 static int fat_show_options(struct seq_file *m, struct dentry *root);
928 static const struct super_operations fat_sops = {
929         .alloc_inode    = fat_alloc_inode,
930         .free_inode     = fat_free_inode,
931         .write_inode    = fat_write_inode,
932         .evict_inode    = fat_evict_inode,
933         .put_super      = fat_put_super,
934         .statfs         = fat_statfs,
935         .remount_fs     = fat_remount,
936 
937         .show_options   = fat_show_options,
938 };
939 
940 static int fat_show_options(struct seq_file *m, struct dentry *root)
941 {
942         struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
943         struct fat_mount_options *opts = &sbi->options;
944         int isvfat = opts->isvfat;
945 
946         if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
947                 seq_printf(m, ",uid=%u",
948                                 from_kuid_munged(&init_user_ns, opts->fs_uid));
949         if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
950                 seq_printf(m, ",gid=%u",
951                                 from_kgid_munged(&init_user_ns, opts->fs_gid));
952         seq_printf(m, ",fmask=%04o", opts->fs_fmask);
953         seq_printf(m, ",dmask=%04o", opts->fs_dmask);
954         if (opts->allow_utime)
955                 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
956         if (sbi->nls_disk)
957                 /* strip "cp" prefix from displayed option */
958                 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
959         if (isvfat) {
960                 if (sbi->nls_io)
961                         seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
962 
963                 switch (opts->shortname) {
964                 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
965                         seq_puts(m, ",shortname=win95");
966                         break;
967                 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
968                         seq_puts(m, ",shortname=winnt");
969                         break;
970                 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
971                         seq_puts(m, ",shortname=mixed");
972                         break;
973                 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
974                         seq_puts(m, ",shortname=lower");
975                         break;
976                 default:
977                         seq_puts(m, ",shortname=unknown");
978                         break;
979                 }
980         }
981         if (opts->name_check != 'n')
982                 seq_printf(m, ",check=%c", opts->name_check);
983         if (opts->usefree)
984                 seq_puts(m, ",usefree");
985         if (opts->quiet)
986                 seq_puts(m, ",quiet");
987         if (opts->showexec)
988                 seq_puts(m, ",showexec");
989         if (opts->sys_immutable)
990                 seq_puts(m, ",sys_immutable");
991         if (!isvfat) {
992                 if (opts->dotsOK)
993                         seq_puts(m, ",dotsOK=yes");
994                 if (opts->nocase)
995                         seq_puts(m, ",nocase");
996         } else {
997                 if (opts->utf8)
998                         seq_puts(m, ",utf8");
999                 if (opts->unicode_xlate)
1000                         seq_puts(m, ",uni_xlate");
1001                 if (!opts->numtail)
1002                         seq_puts(m, ",nonumtail");
1003                 if (opts->rodir)
1004                         seq_puts(m, ",rodir");
1005         }
1006         if (opts->flush)
1007                 seq_puts(m, ",flush");
1008         if (opts->tz_set) {
1009                 if (opts->time_offset)
1010                         seq_printf(m, ",time_offset=%d", opts->time_offset);
1011                 else
1012                         seq_puts(m, ",tz=UTC");
1013         }
1014         if (opts->errors == FAT_ERRORS_CONT)
1015                 seq_puts(m, ",errors=continue");
1016         else if (opts->errors == FAT_ERRORS_PANIC)
1017                 seq_puts(m, ",errors=panic");
1018         else
1019                 seq_puts(m, ",errors=remount-ro");
1020         if (opts->nfs == FAT_NFS_NOSTALE_RO)
1021                 seq_puts(m, ",nfs=nostale_ro");
1022         else if (opts->nfs)
1023                 seq_puts(m, ",nfs=stale_rw");
1024         if (opts->discard)
1025                 seq_puts(m, ",discard");
1026         if (opts->dos1xfloppy)
1027                 seq_puts(m, ",dos1xfloppy");
1028 
1029         return 0;
1030 }
1031 
1032 enum {
1033         Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
1034         Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
1035         Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
1036         Opt_immutable, Opt_dots, Opt_nodots,
1037         Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
1038         Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
1039         Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
1040         Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
1041         Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
1042         Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
1043 };
1044 
1045 static const match_table_t fat_tokens = {
1046         {Opt_check_r, "check=relaxed"},
1047         {Opt_check_s, "check=strict"},
1048         {Opt_check_n, "check=normal"},
1049         {Opt_check_r, "check=r"},
1050         {Opt_check_s, "check=s"},
1051         {Opt_check_n, "check=n"},
1052         {Opt_uid, "uid=%u"},
1053         {Opt_gid, "gid=%u"},
1054         {Opt_umask, "umask=%o"},
1055         {Opt_dmask, "dmask=%o"},
1056         {Opt_fmask, "fmask=%o"},
1057         {Opt_allow_utime, "allow_utime=%o"},
1058         {Opt_codepage, "codepage=%u"},
1059         {Opt_usefree, "usefree"},
1060         {Opt_nocase, "nocase"},
1061         {Opt_quiet, "quiet"},
1062         {Opt_showexec, "showexec"},
1063         {Opt_debug, "debug"},
1064         {Opt_immutable, "sys_immutable"},
1065         {Opt_flush, "flush"},
1066         {Opt_tz_utc, "tz=UTC"},
1067         {Opt_time_offset, "time_offset=%d"},
1068         {Opt_err_cont, "errors=continue"},
1069         {Opt_err_panic, "errors=panic"},
1070         {Opt_err_ro, "errors=remount-ro"},
1071         {Opt_discard, "discard"},
1072         {Opt_nfs_stale_rw, "nfs"},
1073         {Opt_nfs_stale_rw, "nfs=stale_rw"},
1074         {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
1075         {Opt_dos1xfloppy, "dos1xfloppy"},
1076         {Opt_obsolete, "conv=binary"},
1077         {Opt_obsolete, "conv=text"},
1078         {Opt_obsolete, "conv=auto"},
1079         {Opt_obsolete, "conv=b"},
1080         {Opt_obsolete, "conv=t"},
1081         {Opt_obsolete, "conv=a"},
1082         {Opt_obsolete, "fat=%u"},
1083         {Opt_obsolete, "blocksize=%u"},
1084         {Opt_obsolete, "cvf_format=%20s"},
1085         {Opt_obsolete, "cvf_options=%100s"},
1086         {Opt_obsolete, "posix"},
1087         {Opt_err, NULL},
1088 };
1089 static const match_table_t msdos_tokens = {
1090         {Opt_nodots, "nodots"},
1091         {Opt_nodots, "dotsOK=no"},
1092         {Opt_dots, "dots"},
1093         {Opt_dots, "dotsOK=yes"},
1094         {Opt_err, NULL}
1095 };
1096 static const match_table_t vfat_tokens = {
1097         {Opt_charset, "iocharset=%s"},
1098         {Opt_shortname_lower, "shortname=lower"},
1099         {Opt_shortname_win95, "shortname=win95"},
1100         {Opt_shortname_winnt, "shortname=winnt"},
1101         {Opt_shortname_mixed, "shortname=mixed"},
1102         {Opt_utf8_no, "utf8=0"},                /* 0 or no or false */
1103         {Opt_utf8_no, "utf8=no"},
1104         {Opt_utf8_no, "utf8=false"},
1105         {Opt_utf8_yes, "utf8=1"},               /* empty or 1 or yes or true */
1106         {Opt_utf8_yes, "utf8=yes"},
1107         {Opt_utf8_yes, "utf8=true"},
1108         {Opt_utf8_yes, "utf8"},
1109         {Opt_uni_xl_no, "uni_xlate=0"},         /* 0 or no or false */
1110         {Opt_uni_xl_no, "uni_xlate=no"},
1111         {Opt_uni_xl_no, "uni_xlate=false"},
1112         {Opt_uni_xl_yes, "uni_xlate=1"},        /* empty or 1 or yes or true */
1113         {Opt_uni_xl_yes, "uni_xlate=yes"},
1114         {Opt_uni_xl_yes, "uni_xlate=true"},
1115         {Opt_uni_xl_yes, "uni_xlate"},
1116         {Opt_nonumtail_no, "nonumtail=0"},      /* 0 or no or false */
1117         {Opt_nonumtail_no, "nonumtail=no"},
1118         {Opt_nonumtail_no, "nonumtail=false"},
1119         {Opt_nonumtail_yes, "nonumtail=1"},     /* empty or 1 or yes or true */
1120         {Opt_nonumtail_yes, "nonumtail=yes"},
1121         {Opt_nonumtail_yes, "nonumtail=true"},
1122         {Opt_nonumtail_yes, "nonumtail"},
1123         {Opt_rodir, "rodir"},
1124         {Opt_err, NULL}
1125 };
1126 
1127 static int parse_options(struct super_block *sb, char *options, int is_vfat,
1128                          int silent, int *debug, struct fat_mount_options *opts)
1129 {
1130         char *p;
1131         substring_t args[MAX_OPT_ARGS];
1132         int option;
1133         char *iocharset;
1134 
1135         opts->isvfat = is_vfat;
1136 
1137         opts->fs_uid = current_uid();
1138         opts->fs_gid = current_gid();
1139         opts->fs_fmask = opts->fs_dmask = current_umask();
1140         opts->allow_utime = -1;
1141         opts->codepage = fat_default_codepage;
1142         fat_reset_iocharset(opts);
1143         if (is_vfat) {
1144                 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1145                 opts->rodir = 0;
1146         } else {
1147                 opts->shortname = 0;
1148                 opts->rodir = 1;
1149         }
1150         opts->name_check = 'n';
1151         opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK =  0;
1152         opts->unicode_xlate = 0;
1153         opts->numtail = 1;
1154         opts->usefree = opts->nocase = 0;
1155         opts->tz_set = 0;
1156         opts->nfs = 0;
1157         opts->errors = FAT_ERRORS_RO;
1158         *debug = 0;
1159 
1160         opts->utf8 = IS_ENABLED(CONFIG_FAT_DEFAULT_UTF8) && is_vfat;
1161 
1162         if (!options)
1163                 goto out;
1164 
1165         while ((p = strsep(&options, ",")) != NULL) {
1166                 int token;
1167                 if (!*p)
1168                         continue;
1169 
1170                 token = match_token(p, fat_tokens, args);
1171                 if (token == Opt_err) {
1172                         if (is_vfat)
1173                                 token = match_token(p, vfat_tokens, args);
1174                         else
1175                                 token = match_token(p, msdos_tokens, args);
1176                 }
1177                 switch (token) {
1178                 case Opt_check_s:
1179                         opts->name_check = 's';
1180                         break;
1181                 case Opt_check_r:
1182                         opts->name_check = 'r';
1183                         break;
1184                 case Opt_check_n:
1185                         opts->name_check = 'n';
1186                         break;
1187                 case Opt_usefree:
1188                         opts->usefree = 1;
1189                         break;
1190                 case Opt_nocase:
1191                         if (!is_vfat)
1192                                 opts->nocase = 1;
1193                         else {
1194                                 /* for backward compatibility */
1195                                 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1196                                         | VFAT_SFN_CREATE_WIN95;
1197                         }
1198                         break;
1199                 case Opt_quiet:
1200                         opts->quiet = 1;
1201                         break;
1202                 case Opt_showexec:
1203                         opts->showexec = 1;
1204                         break;
1205                 case Opt_debug:
1206                         *debug = 1;
1207                         break;
1208                 case Opt_immutable:
1209                         opts->sys_immutable = 1;
1210                         break;
1211                 case Opt_uid:
1212                         if (match_int(&args[0], &option))
1213                                 return -EINVAL;
1214                         opts->fs_uid = make_kuid(current_user_ns(), option);
1215                         if (!uid_valid(opts->fs_uid))
1216                                 return -EINVAL;
1217                         break;
1218                 case Opt_gid:
1219                         if (match_int(&args[0], &option))
1220                                 return -EINVAL;
1221                         opts->fs_gid = make_kgid(current_user_ns(), option);
1222                         if (!gid_valid(opts->fs_gid))
1223                                 return -EINVAL;
1224                         break;
1225                 case Opt_umask:
1226                         if (match_octal(&args[0], &option))
1227                                 return -EINVAL;
1228                         opts->fs_fmask = opts->fs_dmask = option;
1229                         break;
1230                 case Opt_dmask:
1231                         if (match_octal(&args[0], &option))
1232                                 return -EINVAL;
1233                         opts->fs_dmask = option;
1234                         break;
1235                 case Opt_fmask:
1236                         if (match_octal(&args[0], &option))
1237                                 return -EINVAL;
1238                         opts->fs_fmask = option;
1239                         break;
1240                 case Opt_allow_utime:
1241                         if (match_octal(&args[0], &option))
1242                                 return -EINVAL;
1243                         opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1244                         break;
1245                 case Opt_codepage:
1246                         if (match_int(&args[0], &option))
1247                                 return -EINVAL;
1248                         opts->codepage = option;
1249                         break;
1250                 case Opt_flush:
1251                         opts->flush = 1;
1252                         break;
1253                 case Opt_time_offset:
1254                         if (match_int(&args[0], &option))
1255                                 return -EINVAL;
1256                         /*
1257                          * GMT+-12 zones may have DST corrections so at least
1258                          * 13 hours difference is needed. Make the limit 24
1259                          * just in case someone invents something unusual.
1260                          */
1261                         if (option < -24 * 60 || option > 24 * 60)
1262                                 return -EINVAL;
1263                         opts->tz_set = 1;
1264                         opts->time_offset = option;
1265                         break;
1266                 case Opt_tz_utc:
1267                         opts->tz_set = 1;
1268                         opts->time_offset = 0;
1269                         break;
1270                 case Opt_err_cont:
1271                         opts->errors = FAT_ERRORS_CONT;
1272                         break;
1273                 case Opt_err_panic:
1274                         opts->errors = FAT_ERRORS_PANIC;
1275                         break;
1276                 case Opt_err_ro:
1277                         opts->errors = FAT_ERRORS_RO;
1278                         break;
1279                 case Opt_nfs_stale_rw:
1280                         opts->nfs = FAT_NFS_STALE_RW;
1281                         break;
1282                 case Opt_nfs_nostale_ro:
1283                         opts->nfs = FAT_NFS_NOSTALE_RO;
1284                         break;
1285                 case Opt_dos1xfloppy:
1286                         opts->dos1xfloppy = 1;
1287                         break;
1288 
1289                 /* msdos specific */
1290                 case Opt_dots:
1291                         opts->dotsOK = 1;
1292                         break;
1293                 case Opt_nodots:
1294                         opts->dotsOK = 0;
1295                         break;
1296 
1297                 /* vfat specific */
1298                 case Opt_charset:
1299                         fat_reset_iocharset(opts);
1300                         iocharset = match_strdup(&args[0]);
1301                         if (!iocharset)
1302                                 return -ENOMEM;
1303                         opts->iocharset = iocharset;
1304                         break;
1305                 case Opt_shortname_lower:
1306                         opts->shortname = VFAT_SFN_DISPLAY_LOWER
1307                                         | VFAT_SFN_CREATE_WIN95;
1308                         break;
1309                 case Opt_shortname_win95:
1310                         opts->shortname = VFAT_SFN_DISPLAY_WIN95
1311                                         | VFAT_SFN_CREATE_WIN95;
1312                         break;
1313                 case Opt_shortname_winnt:
1314                         opts->shortname = VFAT_SFN_DISPLAY_WINNT
1315                                         | VFAT_SFN_CREATE_WINNT;
1316                         break;
1317                 case Opt_shortname_mixed:
1318                         opts->shortname = VFAT_SFN_DISPLAY_WINNT
1319                                         | VFAT_SFN_CREATE_WIN95;
1320                         break;
1321                 case Opt_utf8_no:               /* 0 or no or false */
1322                         opts->utf8 = 0;
1323                         break;
1324                 case Opt_utf8_yes:              /* empty or 1 or yes or true */
1325                         opts->utf8 = 1;
1326                         break;
1327                 case Opt_uni_xl_no:             /* 0 or no or false */
1328                         opts->unicode_xlate = 0;
1329                         break;
1330                 case Opt_uni_xl_yes:            /* empty or 1 or yes or true */
1331                         opts->unicode_xlate = 1;
1332                         break;
1333                 case Opt_nonumtail_no:          /* 0 or no or false */
1334                         opts->numtail = 1;      /* negated option */
1335                         break;
1336                 case Opt_nonumtail_yes:         /* empty or 1 or yes or true */
1337                         opts->numtail = 0;      /* negated option */
1338                         break;
1339                 case Opt_rodir:
1340                         opts->rodir = 1;
1341                         break;
1342                 case Opt_discard:
1343                         opts->discard = 1;
1344                         break;
1345 
1346                 /* obsolete mount options */
1347                 case Opt_obsolete:
1348                         fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1349                                "not supported now", p);
1350                         break;
1351                 /* unknown option */
1352                 default:
1353                         if (!silent) {
1354                                 fat_msg(sb, KERN_ERR,
1355                                        "Unrecognized mount option \"%s\" "
1356                                        "or missing value", p);
1357                         }
1358                         return -EINVAL;
1359                 }
1360         }
1361 
1362 out:
1363         /* UTF-8 doesn't provide FAT semantics */
1364         if (!strcmp(opts->iocharset, "utf8")) {
1365                 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1366                        " for FAT filesystems, filesystem will be "
1367                        "case sensitive!");
1368         }
1369 
1370         /* If user doesn't specify allow_utime, it's initialized from dmask. */
1371         if (opts->allow_utime == (unsigned short)-1)
1372                 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1373         if (opts->unicode_xlate)
1374                 opts->utf8 = 0;
1375         if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1376                 sb->s_flags |= SB_RDONLY;
1377                 sb->s_export_op = &fat_export_ops_nostale;
1378         }
1379 
1380         return 0;
1381 }
1382 
1383 static int fat_read_root(struct inode *inode)
1384 {
1385         struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1386         int error;
1387 
1388         MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1389         inode->i_uid = sbi->options.fs_uid;
1390         inode->i_gid = sbi->options.fs_gid;
1391         inode_inc_iversion(inode);
1392         inode->i_generation = 0;
1393         inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1394         inode->i_op = sbi->dir_ops;
1395         inode->i_fop = &fat_dir_operations;
1396         if (is_fat32(sbi)) {
1397                 MSDOS_I(inode)->i_start = sbi->root_cluster;
1398                 error = fat_calc_dir_size(inode);
1399                 if (error < 0)
1400                         return error;
1401         } else {
1402                 MSDOS_I(inode)->i_start = 0;
1403                 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1404         }
1405         inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1406                            & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1407         MSDOS_I(inode)->i_logstart = 0;
1408         MSDOS_I(inode)->mmu_private = inode->i_size;
1409 
1410         fat_save_attrs(inode, ATTR_DIR);
1411         inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1412         inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1413         set_nlink(inode, fat_subdirs(inode)+2);
1414 
1415         return 0;
1416 }
1417 
1418 static unsigned long calc_fat_clusters(struct super_block *sb)
1419 {
1420         struct msdos_sb_info *sbi = MSDOS_SB(sb);
1421 
1422         /* Divide first to avoid overflow */
1423         if (!is_fat12(sbi)) {
1424                 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1425                 return ent_per_sec * sbi->fat_length;
1426         }
1427 
1428         return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1429 }
1430 
1431 static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1432 {
1433         if (get_unaligned_le16(&b->sector_size))
1434                 return false;
1435         if (b->sec_per_clus)
1436                 return false;
1437         if (b->reserved)
1438                 return false;
1439         if (b->fats)
1440                 return false;
1441         if (get_unaligned_le16(&b->dir_entries))
1442                 return false;
1443         if (get_unaligned_le16(&b->sectors))
1444                 return false;
1445         if (b->media)
1446                 return false;
1447         if (b->fat_length)
1448                 return false;
1449         if (b->secs_track)
1450                 return false;
1451         if (b->heads)
1452                 return false;
1453         return true;
1454 }
1455 
1456 static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1457         int silent, struct fat_bios_param_block *bpb)
1458 {
1459         int error = -EINVAL;
1460 
1461         /* Read in BPB ... */
1462         memset(bpb, 0, sizeof(*bpb));
1463         bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1464         bpb->fat_sec_per_clus = b->sec_per_clus;
1465         bpb->fat_reserved = le16_to_cpu(b->reserved);
1466         bpb->fat_fats = b->fats;
1467         bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1468         bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1469         bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1470         bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1471 
1472         bpb->fat16_state = b->fat16.state;
1473         bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1474 
1475         bpb->fat32_length = le32_to_cpu(b->fat32.length);
1476         bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1477         bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1478         bpb->fat32_state = b->fat32.state;
1479         bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1480 
1481         /* Validate this looks like a FAT filesystem BPB */
1482         if (!bpb->fat_reserved) {
1483                 if (!silent)
1484                         fat_msg(sb, KERN_ERR,
1485                                 "bogus number of reserved sectors");
1486                 goto out;
1487         }
1488         if (!bpb->fat_fats) {
1489                 if (!silent)
1490                         fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1491                 goto out;
1492         }
1493 
1494         /*
1495          * Earlier we checked here that b->secs_track and b->head are nonzero,
1496          * but it turns out valid FAT filesystems can have zero there.
1497          */
1498 
1499         if (!fat_valid_media(b->media)) {
1500                 if (!silent)
1501                         fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1502                                 (unsigned)b->media);
1503                 goto out;
1504         }
1505 
1506         if (!is_power_of_2(bpb->fat_sector_size)
1507             || (bpb->fat_sector_size < 512)
1508             || (bpb->fat_sector_size > 4096)) {
1509                 if (!silent)
1510                         fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1511                                (unsigned)bpb->fat_sector_size);
1512                 goto out;
1513         }
1514 
1515         if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1516                 if (!silent)
1517                         fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1518                                 (unsigned)bpb->fat_sec_per_clus);
1519                 goto out;
1520         }
1521 
1522         error = 0;
1523 
1524 out:
1525         return error;
1526 }
1527 
1528 static int fat_read_static_bpb(struct super_block *sb,
1529         struct fat_boot_sector *b, int silent,
1530         struct fat_bios_param_block *bpb)
1531 {
1532         static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1533 
1534         struct fat_floppy_defaults *fdefaults = NULL;
1535         int error = -EINVAL;
1536         sector_t bd_sects;
1537         unsigned i;
1538 
1539         bd_sects = i_size_read(sb->s_bdev->bd_inode) / SECTOR_SIZE;
1540 
1541         /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1542         if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1543                 if (!silent)
1544                         fat_msg(sb, KERN_ERR,
1545                                 "%s; no bootstrapping code", notdos1x);
1546                 goto out;
1547         }
1548 
1549         /*
1550          * If any value in this region is non-zero, it isn't archaic
1551          * DOS.
1552          */
1553         if (!fat_bpb_is_zero(b)) {
1554                 if (!silent)
1555                         fat_msg(sb, KERN_ERR,
1556                                 "%s; DOS 2.x BPB is non-zero", notdos1x);
1557                 goto out;
1558         }
1559 
1560         for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1561                 if (floppy_defaults[i].nr_sectors == bd_sects) {
1562                         fdefaults = &floppy_defaults[i];
1563                         break;
1564                 }
1565         }
1566 
1567         if (fdefaults == NULL) {
1568                 if (!silent)
1569                         fat_msg(sb, KERN_WARNING,
1570                                 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1571                                 (u64)bd_sects);
1572                 goto out;
1573         }
1574 
1575         if (!silent)
1576                 fat_msg(sb, KERN_INFO,
1577                         "This looks like a DOS 1.x volume; assuming default BPB values");
1578 
1579         memset(bpb, 0, sizeof(*bpb));
1580         bpb->fat_sector_size = SECTOR_SIZE;
1581         bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1582         bpb->fat_reserved = 1;
1583         bpb->fat_fats = 2;
1584         bpb->fat_dir_entries = fdefaults->dir_entries;
1585         bpb->fat_sectors = fdefaults->nr_sectors;
1586         bpb->fat_fat_length = fdefaults->fat_length;
1587 
1588         error = 0;
1589 
1590 out:
1591         return error;
1592 }
1593 
1594 /*
1595  * Read the super block of an MS-DOS FS.
1596  */
1597 int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1598                    void (*setup)(struct super_block *))
1599 {
1600         struct inode *root_inode = NULL, *fat_inode = NULL;
1601         struct inode *fsinfo_inode = NULL;
1602         struct buffer_head *bh;
1603         struct fat_bios_param_block bpb;
1604         struct msdos_sb_info *sbi;
1605         u16 logical_sector_size;
1606         u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1607         int debug;
1608         long error;
1609         char buf[50];
1610         struct timespec64 ts;
1611 
1612         /*
1613          * GFP_KERNEL is ok here, because while we do hold the
1614          * superblock lock, memory pressure can't call back into
1615          * the filesystem, since we're only just about to mount
1616          * it and have no inodes etc active!
1617          */
1618         sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1619         if (!sbi)
1620                 return -ENOMEM;
1621         sb->s_fs_info = sbi;
1622 
1623         sb->s_flags |= SB_NODIRATIME;
1624         sb->s_magic = MSDOS_SUPER_MAGIC;
1625         sb->s_op = &fat_sops;
1626         sb->s_export_op = &fat_export_ops;
1627         /*
1628          * fat timestamps are complex and truncated by fat itself, so
1629          * we set 1 here to be fast
1630          */
1631         sb->s_time_gran = 1;
1632         mutex_init(&sbi->nfs_build_inode_lock);
1633         ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1634                              DEFAULT_RATELIMIT_BURST);
1635 
1636         error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1637         if (error)
1638                 goto out_fail;
1639 
1640         setup(sb); /* flavour-specific stuff that needs options */
1641 
1642         error = -EIO;
1643         sb_min_blocksize(sb, 512);
1644         bh = sb_bread(sb, 0);
1645         if (bh == NULL) {
1646                 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1647                 goto out_fail;
1648         }
1649 
1650         error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1651                 &bpb);
1652         if (error == -EINVAL && sbi->options.dos1xfloppy)
1653                 error = fat_read_static_bpb(sb,
1654                         (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1655         brelse(bh);
1656 
1657         if (error == -EINVAL)
1658                 goto out_invalid;
1659         else if (error)
1660                 goto out_fail;
1661 
1662         logical_sector_size = bpb.fat_sector_size;
1663         sbi->sec_per_clus = bpb.fat_sec_per_clus;
1664 
1665         error = -EIO;
1666         if (logical_sector_size < sb->s_blocksize) {
1667                 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1668                        " (logical sector size = %u)", logical_sector_size);
1669                 goto out_fail;
1670         }
1671 
1672         if (logical_sector_size > sb->s_blocksize) {
1673                 struct buffer_head *bh_resize;
1674 
1675                 if (!sb_set_blocksize(sb, logical_sector_size)) {
1676                         fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1677                                logical_sector_size);
1678                         goto out_fail;
1679                 }
1680 
1681                 /* Verify that the larger boot sector is fully readable */
1682                 bh_resize = sb_bread(sb, 0);
1683                 if (bh_resize == NULL) {
1684                         fat_msg(sb, KERN_ERR, "unable to read boot sector"
1685                                " (logical sector size = %lu)",
1686                                sb->s_blocksize);
1687                         goto out_fail;
1688                 }
1689                 brelse(bh_resize);
1690         }
1691 
1692         mutex_init(&sbi->s_lock);
1693         sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1694         sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1695         sbi->fats = bpb.fat_fats;
1696         sbi->fat_bits = 0;              /* Don't know yet */
1697         sbi->fat_start = bpb.fat_reserved;
1698         sbi->fat_length = bpb.fat_fat_length;
1699         sbi->root_cluster = 0;
1700         sbi->free_clusters = -1;        /* Don't know yet */
1701         sbi->free_clus_valid = 0;
1702         sbi->prev_free = FAT_START_ENT;
1703         sb->s_maxbytes = 0xffffffff;
1704         fat_time_fat2unix(sbi, &ts, 0, cpu_to_le16(FAT_DATE_MIN), 0);
1705         sb->s_time_min = ts.tv_sec;
1706 
1707         fat_time_fat2unix(sbi, &ts, cpu_to_le16(FAT_TIME_MAX),
1708                           cpu_to_le16(FAT_DATE_MAX), 0);
1709         sb->s_time_max = ts.tv_sec;
1710 
1711         if (!sbi->fat_length && bpb.fat32_length) {
1712                 struct fat_boot_fsinfo *fsinfo;
1713                 struct buffer_head *fsinfo_bh;
1714 
1715                 /* Must be FAT32 */
1716                 sbi->fat_bits = 32;
1717                 sbi->fat_length = bpb.fat32_length;
1718                 sbi->root_cluster = bpb.fat32_root_cluster;
1719 
1720                 /* MC - if info_sector is 0, don't multiply by 0 */
1721                 sbi->fsinfo_sector = bpb.fat32_info_sector;
1722                 if (sbi->fsinfo_sector == 0)
1723                         sbi->fsinfo_sector = 1;
1724 
1725                 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1726                 if (fsinfo_bh == NULL) {
1727                         fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1728                                " (sector = %lu)", sbi->fsinfo_sector);
1729                         goto out_fail;
1730                 }
1731 
1732                 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1733                 if (!IS_FSINFO(fsinfo)) {
1734                         fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1735                                "0x%08x, 0x%08x (sector = %lu)",
1736                                le32_to_cpu(fsinfo->signature1),
1737                                le32_to_cpu(fsinfo->signature2),
1738                                sbi->fsinfo_sector);
1739                 } else {
1740                         if (sbi->options.usefree)
1741                                 sbi->free_clus_valid = 1;
1742                         sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1743                         sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1744                 }
1745 
1746                 brelse(fsinfo_bh);
1747         }
1748 
1749         /* interpret volume ID as a little endian 32 bit integer */
1750         if (is_fat32(sbi))
1751                 sbi->vol_id = bpb.fat32_vol_id;
1752         else /* fat 16 or 12 */
1753                 sbi->vol_id = bpb.fat16_vol_id;
1754 
1755         sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1756         sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1757 
1758         sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1759         sbi->dir_entries = bpb.fat_dir_entries;
1760         if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1761                 if (!silent)
1762                         fat_msg(sb, KERN_ERR, "bogus number of directory entries"
1763                                " (%u)", sbi->dir_entries);
1764                 goto out_invalid;
1765         }
1766 
1767         rootdir_sectors = sbi->dir_entries
1768                 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1769         sbi->data_start = sbi->dir_start + rootdir_sectors;
1770         total_sectors = bpb.fat_sectors;
1771         if (total_sectors == 0)
1772                 total_sectors = bpb.fat_total_sect;
1773 
1774         total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1775 
1776         if (!is_fat32(sbi))
1777                 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1778 
1779         /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1780         if (is_fat32(sbi))
1781                 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1782         else /* fat 16 or 12 */
1783                 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1784 
1785         /* check that FAT table does not overflow */
1786         fat_clusters = calc_fat_clusters(sb);
1787         total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1788         if (total_clusters > max_fat(sb)) {
1789                 if (!silent)
1790                         fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1791                                total_clusters);
1792                 goto out_invalid;
1793         }
1794 
1795         sbi->max_cluster = total_clusters + FAT_START_ENT;
1796         /* check the free_clusters, it's not necessarily correct */
1797         if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1798                 sbi->free_clusters = -1;
1799         /* check the prev_free, it's not necessarily correct */
1800         sbi->prev_free %= sbi->max_cluster;
1801         if (sbi->prev_free < FAT_START_ENT)
1802                 sbi->prev_free = FAT_START_ENT;
1803 
1804         /* set up enough so that it can read an inode */
1805         fat_hash_init(sb);
1806         dir_hash_init(sb);
1807         fat_ent_access_init(sb);
1808 
1809         /*
1810          * The low byte of the first FAT entry must have the same value as
1811          * the media field of the boot sector. But in real world, too many
1812          * devices are writing wrong values. So, removed that validity check.
1813          *
1814          * The removed check compared the first FAT entry to a value dependent
1815          * on the media field like this:
1816          * == (0x0F00 | media), for FAT12
1817          * == (0XFF00 | media), for FAT16
1818          * == (0x0FFFFF | media), for FAT32
1819          */
1820 
1821         error = -EINVAL;
1822         sprintf(buf, "cp%d", sbi->options.codepage);
1823         sbi->nls_disk = load_nls(buf);
1824         if (!sbi->nls_disk) {
1825                 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1826                 goto out_fail;
1827         }
1828 
1829         /* FIXME: utf8 is using iocharset for upper/lower conversion */
1830         if (sbi->options.isvfat) {
1831                 sbi->nls_io = load_nls(sbi->options.iocharset);
1832                 if (!sbi->nls_io) {
1833                         fat_msg(sb, KERN_ERR, "IO charset %s not found",
1834                                sbi->options.iocharset);
1835                         goto out_fail;
1836                 }
1837         }
1838 
1839         error = -ENOMEM;
1840         fat_inode = new_inode(sb);
1841         if (!fat_inode)
1842                 goto out_fail;
1843         sbi->fat_inode = fat_inode;
1844 
1845         fsinfo_inode = new_inode(sb);
1846         if (!fsinfo_inode)
1847                 goto out_fail;
1848         fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1849         sbi->fsinfo_inode = fsinfo_inode;
1850         insert_inode_hash(fsinfo_inode);
1851 
1852         root_inode = new_inode(sb);
1853         if (!root_inode)
1854                 goto out_fail;
1855         root_inode->i_ino = MSDOS_ROOT_INO;
1856         inode_set_iversion(root_inode, 1);
1857         error = fat_read_root(root_inode);
1858         if (error < 0) {
1859                 iput(root_inode);
1860                 goto out_fail;
1861         }
1862         error = -ENOMEM;
1863         insert_inode_hash(root_inode);
1864         fat_attach(root_inode, 0);
1865         sb->s_root = d_make_root(root_inode);
1866         if (!sb->s_root) {
1867                 fat_msg(sb, KERN_ERR, "get root inode failed");
1868                 goto out_fail;
1869         }
1870 
1871         if (sbi->options.discard) {
1872                 struct request_queue *q = bdev_get_queue(sb->s_bdev);
1873                 if (!blk_queue_discard(q))
1874                         fat_msg(sb, KERN_WARNING,
1875                                         "mounting with \"discard\" option, but "
1876                                         "the device does not support discard");
1877         }
1878 
1879         fat_set_state(sb, 1, 0);
1880         return 0;
1881 
1882 out_invalid:
1883         error = -EINVAL;
1884         if (!silent)
1885                 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1886 
1887 out_fail:
1888         if (fsinfo_inode)
1889                 iput(fsinfo_inode);
1890         if (fat_inode)
1891                 iput(fat_inode);
1892         unload_nls(sbi->nls_io);
1893         unload_nls(sbi->nls_disk);
1894         fat_reset_iocharset(&sbi->options);
1895         sb->s_fs_info = NULL;
1896         kfree(sbi);
1897         return error;
1898 }
1899 
1900 EXPORT_SYMBOL_GPL(fat_fill_super);
1901 
1902 /*
1903  * helper function for fat_flush_inodes.  This writes both the inode
1904  * and the file data blocks, waiting for in flight data blocks before
1905  * the start of the call.  It does not wait for any io started
1906  * during the call
1907  */
1908 static int writeback_inode(struct inode *inode)
1909 {
1910 
1911         int ret;
1912 
1913         /* if we used wait=1, sync_inode_metadata waits for the io for the
1914         * inode to finish.  So wait=0 is sent down to sync_inode_metadata
1915         * and filemap_fdatawrite is used for the data blocks
1916         */
1917         ret = sync_inode_metadata(inode, 0);
1918         if (!ret)
1919                 ret = filemap_fdatawrite(inode->i_mapping);
1920         return ret;
1921 }
1922 
1923 /*
1924  * write data and metadata corresponding to i1 and i2.  The io is
1925  * started but we do not wait for any of it to finish.
1926  *
1927  * filemap_flush is used for the block device, so if there is a dirty
1928  * page for a block already in flight, we will not wait and start the
1929  * io over again
1930  */
1931 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1932 {
1933         int ret = 0;
1934         if (!MSDOS_SB(sb)->options.flush)
1935                 return 0;
1936         if (i1)
1937                 ret = writeback_inode(i1);
1938         if (!ret && i2)
1939                 ret = writeback_inode(i2);
1940         if (!ret) {
1941                 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1942                 ret = filemap_flush(mapping);
1943         }
1944         return ret;
1945 }
1946 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1947 
1948 static int __init init_fat_fs(void)
1949 {
1950         int err;
1951 
1952         err = fat_cache_init();
1953         if (err)
1954                 return err;
1955 
1956         err = fat_init_inodecache();
1957         if (err)
1958                 goto failed;
1959 
1960         return 0;
1961 
1962 failed:
1963         fat_cache_destroy();
1964         return err;
1965 }
1966 
1967 static void __exit exit_fat_fs(void)
1968 {
1969         fat_cache_destroy();
1970         fat_destroy_inodecache();
1971 }
1972 
1973 module_init(init_fat_fs)
1974 module_exit(exit_fat_fs)
1975 
1976 MODULE_LICENSE("GPL");
1977 

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