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1/*
2 * linux/fs/fat/inode.c
3 *
4 * Written 1992,1993 by Werner Almesberger
5 * VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
6 * Rewritten for the constant inumbers support by Al Viro
7 *
8 * Fixes:
9 *
10 * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
11 */
12
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/time.h>
16#include <linux/slab.h>
17#include <linux/seq_file.h>
18#include <linux/pagemap.h>
19#include <linux/mpage.h>
20#include <linux/buffer_head.h>
21#include <linux/exportfs.h>
22#include <linux/mount.h>
23#include <linux/vfs.h>
24#include <linux/parser.h>
25#include <linux/uio.h>
26#include <linux/writeback.h>
27#include <linux/log2.h>
28#include <linux/hash.h>
29#include <asm/unaligned.h>
30#include "fat.h"
31
32#ifndef CONFIG_FAT_DEFAULT_IOCHARSET
33/* if user don't select VFAT, this is undefined. */
34#define CONFIG_FAT_DEFAULT_IOCHARSET ""
35#endif
36
37static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
38static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
39
40
41static int fat_add_cluster(struct inode *inode)
42{
43 int err, cluster;
44
45 err = fat_alloc_clusters(inode, &cluster, 1);
46 if (err)
47 return err;
48 /* FIXME: this cluster should be added after data of this
49 * cluster is writed */
50 err = fat_chain_add(inode, cluster, 1);
51 if (err)
52 fat_free_clusters(inode, cluster);
53 return err;
54}
55
56static inline int __fat_get_block(struct inode *inode, sector_t iblock,
57 unsigned long *max_blocks,
58 struct buffer_head *bh_result, int create)
59{
60 struct super_block *sb = inode->i_sb;
61 struct msdos_sb_info *sbi = MSDOS_SB(sb);
62 unsigned long mapped_blocks;
63 sector_t phys;
64 int err, offset;
65
66 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
67 if (err)
68 return err;
69 if (phys) {
70 map_bh(bh_result, sb, phys);
71 *max_blocks = min(mapped_blocks, *max_blocks);
72 return 0;
73 }
74 if (!create)
75 return 0;
76
77 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
78 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
79 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
80 return -EIO;
81 }
82
83 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
84 if (!offset) {
85 /* TODO: multiple cluster allocation would be desirable. */
86 err = fat_add_cluster(inode);
87 if (err)
88 return err;
89 }
90 /* available blocks on this cluster */
91 mapped_blocks = sbi->sec_per_clus - offset;
92
93 *max_blocks = min(mapped_blocks, *max_blocks);
94 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
95
96 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
97 if (err)
98 return err;
99
100 BUG_ON(!phys);
101 BUG_ON(*max_blocks != mapped_blocks);
102 set_buffer_new(bh_result);
103 map_bh(bh_result, sb, phys);
104
105 return 0;
106}
107
108static int fat_get_block(struct inode *inode, sector_t iblock,
109 struct buffer_head *bh_result, int create)
110{
111 struct super_block *sb = inode->i_sb;
112 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
113 int err;
114
115 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
116 if (err)
117 return err;
118 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
119 return 0;
120}
121
122static int fat_writepage(struct page *page, struct writeback_control *wbc)
123{
124 return block_write_full_page(page, fat_get_block, wbc);
125}
126
127static int fat_writepages(struct address_space *mapping,
128 struct writeback_control *wbc)
129{
130 return mpage_writepages(mapping, wbc, fat_get_block);
131}
132
133static int fat_readpage(struct file *file, struct page *page)
134{
135 return mpage_readpage(page, fat_get_block);
136}
137
138static int fat_readpages(struct file *file, struct address_space *mapping,
139 struct list_head *pages, unsigned nr_pages)
140{
141 return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
142}
143
144static void fat_write_failed(struct address_space *mapping, loff_t to)
145{
146 struct inode *inode = mapping->host;
147
148 if (to > inode->i_size) {
149 truncate_pagecache(inode, to, inode->i_size);
150 fat_truncate_blocks(inode, inode->i_size);
151 }
152}
153
154static int fat_write_begin(struct file *file, struct address_space *mapping,
155 loff_t pos, unsigned len, unsigned flags,
156 struct page **pagep, void **fsdata)
157{
158 int err;
159
160 *pagep = NULL;
161 err = cont_write_begin(file, mapping, pos, len, flags,
162 pagep, fsdata, fat_get_block,
163 &MSDOS_I(mapping->host)->mmu_private);
164 if (err < 0)
165 fat_write_failed(mapping, pos + len);
166 return err;
167}
168
169static int fat_write_end(struct file *file, struct address_space *mapping,
170 loff_t pos, unsigned len, unsigned copied,
171 struct page *pagep, void *fsdata)
172{
173 struct inode *inode = mapping->host;
174 int err;
175 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
176 if (err < len)
177 fat_write_failed(mapping, pos + len);
178 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
179 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
180 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
181 mark_inode_dirty(inode);
182 }
183 return err;
184}
185
186static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
187 const struct iovec *iov,
188 loff_t offset, unsigned long nr_segs)
189{
190 struct file *file = iocb->ki_filp;
191 struct address_space *mapping = file->f_mapping;
192 struct inode *inode = mapping->host;
193 ssize_t ret;
194
195 if (rw == WRITE) {
196 /*
197 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
198 * so we need to update the ->mmu_private to block boundary.
199 *
200 * But we must fill the remaining area or hole by nul for
201 * updating ->mmu_private.
202 *
203 * Return 0, and fallback to normal buffered write.
204 */
205 loff_t size = offset + iov_length(iov, nr_segs);
206 if (MSDOS_I(inode)->mmu_private < size)
207 return 0;
208 }
209
210 /*
211 * FAT need to use the DIO_LOCKING for avoiding the race
212 * condition of fat_get_block() and ->truncate().
213 */
214 ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
215 fat_get_block);
216 if (ret < 0 && (rw & WRITE))
217 fat_write_failed(mapping, offset + iov_length(iov, nr_segs));
218
219 return ret;
220}
221
222static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
223{
224 sector_t blocknr;
225
226 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
227 down_read(&MSDOS_I(mapping->host)->truncate_lock);
228 blocknr = generic_block_bmap(mapping, block, fat_get_block);
229 up_read(&MSDOS_I(mapping->host)->truncate_lock);
230
231 return blocknr;
232}
233
234static const struct address_space_operations fat_aops = {
235 .readpage = fat_readpage,
236 .readpages = fat_readpages,
237 .writepage = fat_writepage,
238 .writepages = fat_writepages,
239 .write_begin = fat_write_begin,
240 .write_end = fat_write_end,
241 .direct_IO = fat_direct_IO,
242 .bmap = _fat_bmap
243};
244
245/*
246 * New FAT inode stuff. We do the following:
247 * a) i_ino is constant and has nothing with on-disk location.
248 * b) FAT manages its own cache of directory entries.
249 * c) *This* cache is indexed by on-disk location.
250 * d) inode has an associated directory entry, all right, but
251 * it may be unhashed.
252 * e) currently entries are stored within struct inode. That should
253 * change.
254 * f) we deal with races in the following way:
255 * 1. readdir() and lookup() do FAT-dir-cache lookup.
256 * 2. rename() unhashes the F-d-c entry and rehashes it in
257 * a new place.
258 * 3. unlink() and rmdir() unhash F-d-c entry.
259 * 4. fat_write_inode() checks whether the thing is unhashed.
260 * If it is we silently return. If it isn't we do bread(),
261 * check if the location is still valid and retry if it
262 * isn't. Otherwise we do changes.
263 * 5. Spinlock is used to protect hash/unhash/location check/lookup
264 * 6. fat_evict_inode() unhashes the F-d-c entry.
265 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
266 * and consider negative result as cache miss.
267 */
268
269static void fat_hash_init(struct super_block *sb)
270{
271 struct msdos_sb_info *sbi = MSDOS_SB(sb);
272 int i;
273
274 spin_lock_init(&sbi->inode_hash_lock);
275 for (i = 0; i < FAT_HASH_SIZE; i++)
276 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
277}
278
279static inline unsigned long fat_hash(loff_t i_pos)
280{
281 return hash_32(i_pos, FAT_HASH_BITS);
282}
283
284void fat_attach(struct inode *inode, loff_t i_pos)
285{
286 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
287 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
288
289 spin_lock(&sbi->inode_hash_lock);
290 MSDOS_I(inode)->i_pos = i_pos;
291 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
292 spin_unlock(&sbi->inode_hash_lock);
293}
294EXPORT_SYMBOL_GPL(fat_attach);
295
296void fat_detach(struct inode *inode)
297{
298 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
299 spin_lock(&sbi->inode_hash_lock);
300 MSDOS_I(inode)->i_pos = 0;
301 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
302 spin_unlock(&sbi->inode_hash_lock);
303}
304EXPORT_SYMBOL_GPL(fat_detach);
305
306struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
307{
308 struct msdos_sb_info *sbi = MSDOS_SB(sb);
309 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
310 struct hlist_node *_p;
311 struct msdos_inode_info *i;
312 struct inode *inode = NULL;
313
314 spin_lock(&sbi->inode_hash_lock);
315 hlist_for_each_entry(i, _p, head, i_fat_hash) {
316 BUG_ON(i->vfs_inode.i_sb != sb);
317 if (i->i_pos != i_pos)
318 continue;
319 inode = igrab(&i->vfs_inode);
320 if (inode)
321 break;
322 }
323 spin_unlock(&sbi->inode_hash_lock);
324 return inode;
325}
326
327static int is_exec(unsigned char *extension)
328{
329 unsigned char *exe_extensions = "EXECOMBAT", *walk;
330
331 for (walk = exe_extensions; *walk; walk += 3)
332 if (!strncmp(extension, walk, 3))
333 return 1;
334 return 0;
335}
336
337static int fat_calc_dir_size(struct inode *inode)
338{
339 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
340 int ret, fclus, dclus;
341
342 inode->i_size = 0;
343 if (MSDOS_I(inode)->i_start == 0)
344 return 0;
345
346 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
347 if (ret < 0)
348 return ret;
349 inode->i_size = (fclus + 1) << sbi->cluster_bits;
350
351 return 0;
352}
353
354/* doesn't deal with root inode */
355static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
356{
357 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
358 int error;
359
360 MSDOS_I(inode)->i_pos = 0;
361 inode->i_uid = sbi->options.fs_uid;
362 inode->i_gid = sbi->options.fs_gid;
363 inode->i_version++;
364 inode->i_generation = get_seconds();
365
366 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
367 inode->i_generation &= ~1;
368 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
369 inode->i_op = sbi->dir_ops;
370 inode->i_fop = &fat_dir_operations;
371
372 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
373 if (sbi->fat_bits == 32)
374 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
375
376 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
377 error = fat_calc_dir_size(inode);
378 if (error < 0)
379 return error;
380 MSDOS_I(inode)->mmu_private = inode->i_size;
381
382 inode->i_nlink = fat_subdirs(inode);
383 } else { /* not a directory */
384 inode->i_generation |= 1;
385 inode->i_mode = fat_make_mode(sbi, de->attr,
386 ((sbi->options.showexec && !is_exec(de->name + 8))
387 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
388 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
389 if (sbi->fat_bits == 32)
390 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
391
392 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
393 inode->i_size = le32_to_cpu(de->size);
394 inode->i_op = &fat_file_inode_operations;
395 inode->i_fop = &fat_file_operations;
396 inode->i_mapping->a_ops = &fat_aops;
397 MSDOS_I(inode)->mmu_private = inode->i_size;
398 }
399 if (de->attr & ATTR_SYS) {
400 if (sbi->options.sys_immutable)
401 inode->i_flags |= S_IMMUTABLE;
402 }
403 fat_save_attrs(inode, de->attr);
404
405 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
406 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
407
408 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
409 if (sbi->options.isvfat) {
410 fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
411 de->cdate, de->ctime_cs);
412 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
413 } else
414 inode->i_ctime = inode->i_atime = inode->i_mtime;
415
416 return 0;
417}
418
419struct inode *fat_build_inode(struct super_block *sb,
420 struct msdos_dir_entry *de, loff_t i_pos)
421{
422 struct inode *inode;
423 int err;
424
425 inode = fat_iget(sb, i_pos);
426 if (inode)
427 goto out;
428 inode = new_inode(sb);
429 if (!inode) {
430 inode = ERR_PTR(-ENOMEM);
431 goto out;
432 }
433 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
434 inode->i_version = 1;
435 err = fat_fill_inode(inode, de);
436 if (err) {
437 iput(inode);
438 inode = ERR_PTR(err);
439 goto out;
440 }
441 fat_attach(inode, i_pos);
442 insert_inode_hash(inode);
443out:
444 return inode;
445}
446
447EXPORT_SYMBOL_GPL(fat_build_inode);
448
449static void fat_evict_inode(struct inode *inode)
450{
451 truncate_inode_pages(&inode->i_data, 0);
452 if (!inode->i_nlink) {
453 inode->i_size = 0;
454 fat_truncate_blocks(inode, 0);
455 }
456 invalidate_inode_buffers(inode);
457 end_writeback(inode);
458 fat_cache_inval_inode(inode);
459 fat_detach(inode);
460}
461
462static void fat_write_super(struct super_block *sb)
463{
464 lock_super(sb);
465 sb->s_dirt = 0;
466
467 if (!(sb->s_flags & MS_RDONLY))
468 fat_clusters_flush(sb);
469 unlock_super(sb);
470}
471
472static int fat_sync_fs(struct super_block *sb, int wait)
473{
474 int err = 0;
475
476 if (sb->s_dirt) {
477 lock_super(sb);
478 sb->s_dirt = 0;
479 err = fat_clusters_flush(sb);
480 unlock_super(sb);
481 }
482
483 return err;
484}
485
486static void fat_put_super(struct super_block *sb)
487{
488 struct msdos_sb_info *sbi = MSDOS_SB(sb);
489
490 if (sb->s_dirt)
491 fat_write_super(sb);
492
493 iput(sbi->fat_inode);
494
495 unload_nls(sbi->nls_disk);
496 unload_nls(sbi->nls_io);
497
498 if (sbi->options.iocharset != fat_default_iocharset)
499 kfree(sbi->options.iocharset);
500
501 sb->s_fs_info = NULL;
502 kfree(sbi);
503}
504
505static struct kmem_cache *fat_inode_cachep;
506
507static struct inode *fat_alloc_inode(struct super_block *sb)
508{
509 struct msdos_inode_info *ei;
510 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
511 if (!ei)
512 return NULL;
513
514 init_rwsem(&ei->truncate_lock);
515 return &ei->vfs_inode;
516}
517
518static void fat_i_callback(struct rcu_head *head)
519{
520 struct inode *inode = container_of(head, struct inode, i_rcu);
521 INIT_LIST_HEAD(&inode->i_dentry);
522 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
523}
524
525static void fat_destroy_inode(struct inode *inode)
526{
527 call_rcu(&inode->i_rcu, fat_i_callback);
528}
529
530static void init_once(void *foo)
531{
532 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
533
534 spin_lock_init(&ei->cache_lru_lock);
535 ei->nr_caches = 0;
536 ei->cache_valid_id = FAT_CACHE_VALID + 1;
537 INIT_LIST_HEAD(&ei->cache_lru);
538 INIT_HLIST_NODE(&ei->i_fat_hash);
539 inode_init_once(&ei->vfs_inode);
540}
541
542static int __init fat_init_inodecache(void)
543{
544 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
545 sizeof(struct msdos_inode_info),
546 0, (SLAB_RECLAIM_ACCOUNT|
547 SLAB_MEM_SPREAD),
548 init_once);
549 if (fat_inode_cachep == NULL)
550 return -ENOMEM;
551 return 0;
552}
553
554static void __exit fat_destroy_inodecache(void)
555{
556 kmem_cache_destroy(fat_inode_cachep);
557}
558
559static int fat_remount(struct super_block *sb, int *flags, char *data)
560{
561 struct msdos_sb_info *sbi = MSDOS_SB(sb);
562 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
563 return 0;
564}
565
566static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
567{
568 struct super_block *sb = dentry->d_sb;
569 struct msdos_sb_info *sbi = MSDOS_SB(sb);
570 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
571
572 /* If the count of free cluster is still unknown, counts it here. */
573 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
574 int err = fat_count_free_clusters(dentry->d_sb);
575 if (err)
576 return err;
577 }
578
579 buf->f_type = dentry->d_sb->s_magic;
580 buf->f_bsize = sbi->cluster_size;
581 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
582 buf->f_bfree = sbi->free_clusters;
583 buf->f_bavail = sbi->free_clusters;
584 buf->f_fsid.val[0] = (u32)id;
585 buf->f_fsid.val[1] = (u32)(id >> 32);
586 buf->f_namelen =
587 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
588
589 return 0;
590}
591
592static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
593 struct inode *inode)
594{
595 loff_t i_pos;
596#if BITS_PER_LONG == 32
597 spin_lock(&sbi->inode_hash_lock);
598#endif
599 i_pos = MSDOS_I(inode)->i_pos;
600#if BITS_PER_LONG == 32
601 spin_unlock(&sbi->inode_hash_lock);
602#endif
603 return i_pos;
604}
605
606static int __fat_write_inode(struct inode *inode, int wait)
607{
608 struct super_block *sb = inode->i_sb;
609 struct msdos_sb_info *sbi = MSDOS_SB(sb);
610 struct buffer_head *bh;
611 struct msdos_dir_entry *raw_entry;
612 loff_t i_pos;
613 int err;
614
615 if (inode->i_ino == MSDOS_ROOT_INO)
616 return 0;
617
618retry:
619 i_pos = fat_i_pos_read(sbi, inode);
620 if (!i_pos)
621 return 0;
622
623 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
624 if (!bh) {
625 fat_msg(sb, KERN_ERR, "unable to read inode block "
626 "for updating (i_pos %lld)", i_pos);
627 return -EIO;
628 }
629 spin_lock(&sbi->inode_hash_lock);
630 if (i_pos != MSDOS_I(inode)->i_pos) {
631 spin_unlock(&sbi->inode_hash_lock);
632 brelse(bh);
633 goto retry;
634 }
635
636 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
637 [i_pos & (sbi->dir_per_block - 1)];
638 if (S_ISDIR(inode->i_mode))
639 raw_entry->size = 0;
640 else
641 raw_entry->size = cpu_to_le32(inode->i_size);
642 raw_entry->attr = fat_make_attrs(inode);
643 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
644 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
645 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
646 &raw_entry->date, NULL);
647 if (sbi->options.isvfat) {
648 __le16 atime;
649 fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
650 &raw_entry->cdate, &raw_entry->ctime_cs);
651 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
652 &raw_entry->adate, NULL);
653 }
654 spin_unlock(&sbi->inode_hash_lock);
655 mark_buffer_dirty(bh);
656 err = 0;
657 if (wait)
658 err = sync_dirty_buffer(bh);
659 brelse(bh);
660 return err;
661}
662
663static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
664{
665 return __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
666}
667
668int fat_sync_inode(struct inode *inode)
669{
670 return __fat_write_inode(inode, 1);
671}
672
673EXPORT_SYMBOL_GPL(fat_sync_inode);
674
675static int fat_show_options(struct seq_file *m, struct vfsmount *mnt);
676static const struct super_operations fat_sops = {
677 .alloc_inode = fat_alloc_inode,
678 .destroy_inode = fat_destroy_inode,
679 .write_inode = fat_write_inode,
680 .evict_inode = fat_evict_inode,
681 .put_super = fat_put_super,
682 .write_super = fat_write_super,
683 .sync_fs = fat_sync_fs,
684 .statfs = fat_statfs,
685 .remount_fs = fat_remount,
686
687 .show_options = fat_show_options,
688};
689
690/*
691 * a FAT file handle with fhtype 3 is
692 * 0/ i_ino - for fast, reliable lookup if still in the cache
693 * 1/ i_generation - to see if i_ino is still valid
694 * bit 0 == 0 iff directory
695 * 2/ i_pos(8-39) - if ino has changed, but still in cache
696 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
697 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
698 *
699 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
700 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
701 * of i_logstart is used to store the directory entry offset.
702 */
703
704static struct dentry *fat_fh_to_dentry(struct super_block *sb,
705 struct fid *fid, int fh_len, int fh_type)
706{
707 struct inode *inode = NULL;
708 u32 *fh = fid->raw;
709
710 if (fh_len < 5 || fh_type != 3)
711 return NULL;
712
713 inode = ilookup(sb, fh[0]);
714 if (!inode || inode->i_generation != fh[1]) {
715 if (inode)
716 iput(inode);
717 inode = NULL;
718 }
719 if (!inode) {
720 loff_t i_pos;
721 int i_logstart = fh[3] & 0x0fffffff;
722
723 i_pos = (loff_t)fh[2] << 8;
724 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);
725
726 /* try 2 - see if i_pos is in F-d-c
727 * require i_logstart to be the same
728 * Will fail if you truncate and then re-write
729 */
730
731 inode = fat_iget(sb, i_pos);
732 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
733 iput(inode);
734 inode = NULL;
735 }
736 }
737
738 /*
739 * For now, do nothing if the inode is not found.
740 *
741 * What we could do is:
742 *
743 * - follow the file starting at fh[4], and record the ".." entry,
744 * and the name of the fh[2] entry.
745 * - then follow the ".." file finding the next step up.
746 *
747 * This way we build a path to the root of the tree. If this works, we
748 * lookup the path and so get this inode into the cache. Finally try
749 * the fat_iget lookup again. If that fails, then we are totally out
750 * of luck. But all that is for another day
751 */
752 return d_obtain_alias(inode);
753}
754
755static int
756fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
757{
758 int len = *lenp;
759 struct inode *inode = de->d_inode;
760 u32 ipos_h, ipos_m, ipos_l;
761
762 if (len < 5) {
763 *lenp = 5;
764 return 255; /* no room */
765 }
766
767 ipos_h = MSDOS_I(inode)->i_pos >> 8;
768 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
769 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28;
770 *lenp = 5;
771 fh[0] = inode->i_ino;
772 fh[1] = inode->i_generation;
773 fh[2] = ipos_h;
774 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart;
775 spin_lock(&de->d_lock);
776 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart;
777 spin_unlock(&de->d_lock);
778 return 3;
779}
780
781static struct dentry *fat_get_parent(struct dentry *child)
782{
783 struct super_block *sb = child->d_sb;
784 struct buffer_head *bh;
785 struct msdos_dir_entry *de;
786 loff_t i_pos;
787 struct dentry *parent;
788 struct inode *inode;
789 int err;
790
791 lock_super(sb);
792
793 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos);
794 if (err) {
795 parent = ERR_PTR(err);
796 goto out;
797 }
798 inode = fat_build_inode(sb, de, i_pos);
799 brelse(bh);
800
801 parent = d_obtain_alias(inode);
802out:
803 unlock_super(sb);
804
805 return parent;
806}
807
808static const struct export_operations fat_export_ops = {
809 .encode_fh = fat_encode_fh,
810 .fh_to_dentry = fat_fh_to_dentry,
811 .get_parent = fat_get_parent,
812};
813
814static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
815{
816 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb);
817 struct fat_mount_options *opts = &sbi->options;
818 int isvfat = opts->isvfat;
819
820 if (opts->fs_uid != 0)
821 seq_printf(m, ",uid=%u", opts->fs_uid);
822 if (opts->fs_gid != 0)
823 seq_printf(m, ",gid=%u", opts->fs_gid);
824 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
825 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
826 if (opts->allow_utime)
827 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
828 if (sbi->nls_disk)
829 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset);
830 if (isvfat) {
831 if (sbi->nls_io)
832 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
833
834 switch (opts->shortname) {
835 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
836 seq_puts(m, ",shortname=win95");
837 break;
838 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
839 seq_puts(m, ",shortname=winnt");
840 break;
841 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
842 seq_puts(m, ",shortname=mixed");
843 break;
844 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
845 seq_puts(m, ",shortname=lower");
846 break;
847 default:
848 seq_puts(m, ",shortname=unknown");
849 break;
850 }
851 }
852 if (opts->name_check != 'n')
853 seq_printf(m, ",check=%c", opts->name_check);
854 if (opts->usefree)
855 seq_puts(m, ",usefree");
856 if (opts->quiet)
857 seq_puts(m, ",quiet");
858 if (opts->showexec)
859 seq_puts(m, ",showexec");
860 if (opts->sys_immutable)
861 seq_puts(m, ",sys_immutable");
862 if (!isvfat) {
863 if (opts->dotsOK)
864 seq_puts(m, ",dotsOK=yes");
865 if (opts->nocase)
866 seq_puts(m, ",nocase");
867 } else {
868 if (opts->utf8)
869 seq_puts(m, ",utf8");
870 if (opts->unicode_xlate)
871 seq_puts(m, ",uni_xlate");
872 if (!opts->numtail)
873 seq_puts(m, ",nonumtail");
874 if (opts->rodir)
875 seq_puts(m, ",rodir");
876 }
877 if (opts->flush)
878 seq_puts(m, ",flush");
879 if (opts->tz_utc)
880 seq_puts(m, ",tz=UTC");
881 if (opts->errors == FAT_ERRORS_CONT)
882 seq_puts(m, ",errors=continue");
883 else if (opts->errors == FAT_ERRORS_PANIC)
884 seq_puts(m, ",errors=panic");
885 else
886 seq_puts(m, ",errors=remount-ro");
887 if (opts->discard)
888 seq_puts(m, ",discard");
889
890 return 0;
891}
892
893enum {
894 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
895 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
896 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
897 Opt_immutable, Opt_dots, Opt_nodots,
898 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
899 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
900 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
901 Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
902 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_err,
903};
904
905static const match_table_t fat_tokens = {
906 {Opt_check_r, "check=relaxed"},
907 {Opt_check_s, "check=strict"},
908 {Opt_check_n, "check=normal"},
909 {Opt_check_r, "check=r"},
910 {Opt_check_s, "check=s"},
911 {Opt_check_n, "check=n"},
912 {Opt_uid, "uid=%u"},
913 {Opt_gid, "gid=%u"},
914 {Opt_umask, "umask=%o"},
915 {Opt_dmask, "dmask=%o"},
916 {Opt_fmask, "fmask=%o"},
917 {Opt_allow_utime, "allow_utime=%o"},
918 {Opt_codepage, "codepage=%u"},
919 {Opt_usefree, "usefree"},
920 {Opt_nocase, "nocase"},
921 {Opt_quiet, "quiet"},
922 {Opt_showexec, "showexec"},
923 {Opt_debug, "debug"},
924 {Opt_immutable, "sys_immutable"},
925 {Opt_flush, "flush"},
926 {Opt_tz_utc, "tz=UTC"},
927 {Opt_err_cont, "errors=continue"},
928 {Opt_err_panic, "errors=panic"},
929 {Opt_err_ro, "errors=remount-ro"},
930 {Opt_discard, "discard"},
931 {Opt_obsolate, "conv=binary"},
932 {Opt_obsolate, "conv=text"},
933 {Opt_obsolate, "conv=auto"},
934 {Opt_obsolate, "conv=b"},
935 {Opt_obsolate, "conv=t"},
936 {Opt_obsolate, "conv=a"},
937 {Opt_obsolate, "fat=%u"},
938 {Opt_obsolate, "blocksize=%u"},
939 {Opt_obsolate, "cvf_format=%20s"},
940 {Opt_obsolate, "cvf_options=%100s"},
941 {Opt_obsolate, "posix"},
942 {Opt_err, NULL},
943};
944static const match_table_t msdos_tokens = {
945 {Opt_nodots, "nodots"},
946 {Opt_nodots, "dotsOK=no"},
947 {Opt_dots, "dots"},
948 {Opt_dots, "dotsOK=yes"},
949 {Opt_err, NULL}
950};
951static const match_table_t vfat_tokens = {
952 {Opt_charset, "iocharset=%s"},
953 {Opt_shortname_lower, "shortname=lower"},
954 {Opt_shortname_win95, "shortname=win95"},
955 {Opt_shortname_winnt, "shortname=winnt"},
956 {Opt_shortname_mixed, "shortname=mixed"},
957 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
958 {Opt_utf8_no, "utf8=no"},
959 {Opt_utf8_no, "utf8=false"},
960 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
961 {Opt_utf8_yes, "utf8=yes"},
962 {Opt_utf8_yes, "utf8=true"},
963 {Opt_utf8_yes, "utf8"},
964 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
965 {Opt_uni_xl_no, "uni_xlate=no"},
966 {Opt_uni_xl_no, "uni_xlate=false"},
967 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
968 {Opt_uni_xl_yes, "uni_xlate=yes"},
969 {Opt_uni_xl_yes, "uni_xlate=true"},
970 {Opt_uni_xl_yes, "uni_xlate"},
971 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
972 {Opt_nonumtail_no, "nonumtail=no"},
973 {Opt_nonumtail_no, "nonumtail=false"},
974 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
975 {Opt_nonumtail_yes, "nonumtail=yes"},
976 {Opt_nonumtail_yes, "nonumtail=true"},
977 {Opt_nonumtail_yes, "nonumtail"},
978 {Opt_rodir, "rodir"},
979 {Opt_err, NULL}
980};
981
982static int parse_options(struct super_block *sb, char *options, int is_vfat,
983 int silent, int *debug, struct fat_mount_options *opts)
984{
985 char *p;
986 substring_t args[MAX_OPT_ARGS];
987 int option;
988 char *iocharset;
989
990 opts->isvfat = is_vfat;
991
992 opts->fs_uid = current_uid();
993 opts->fs_gid = current_gid();
994 opts->fs_fmask = opts->fs_dmask = current_umask();
995 opts->allow_utime = -1;
996 opts->codepage = fat_default_codepage;
997 opts->iocharset = fat_default_iocharset;
998 if (is_vfat) {
999 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1000 opts->rodir = 0;
1001 } else {
1002 opts->shortname = 0;
1003 opts->rodir = 1;
1004 }
1005 opts->name_check = 'n';
1006 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
1007 opts->utf8 = opts->unicode_xlate = 0;
1008 opts->numtail = 1;
1009 opts->usefree = opts->nocase = 0;
1010 opts->tz_utc = 0;
1011 opts->errors = FAT_ERRORS_RO;
1012 *debug = 0;
1013
1014 if (!options)
1015 goto out;
1016
1017 while ((p = strsep(&options, ",")) != NULL) {
1018 int token;
1019 if (!*p)
1020 continue;
1021
1022 token = match_token(p, fat_tokens, args);
1023 if (token == Opt_err) {
1024 if (is_vfat)
1025 token = match_token(p, vfat_tokens, args);
1026 else
1027 token = match_token(p, msdos_tokens, args);
1028 }
1029 switch (token) {
1030 case Opt_check_s:
1031 opts->name_check = 's';
1032 break;
1033 case Opt_check_r:
1034 opts->name_check = 'r';
1035 break;
1036 case Opt_check_n:
1037 opts->name_check = 'n';
1038 break;
1039 case Opt_usefree:
1040 opts->usefree = 1;
1041 break;
1042 case Opt_nocase:
1043 if (!is_vfat)
1044 opts->nocase = 1;
1045 else {
1046 /* for backward compatibility */
1047 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1048 | VFAT_SFN_CREATE_WIN95;
1049 }
1050 break;
1051 case Opt_quiet:
1052 opts->quiet = 1;
1053 break;
1054 case Opt_showexec:
1055 opts->showexec = 1;
1056 break;
1057 case Opt_debug:
1058 *debug = 1;
1059 break;
1060 case Opt_immutable:
1061 opts->sys_immutable = 1;
1062 break;
1063 case Opt_uid:
1064 if (match_int(&args[0], &option))
1065 return 0;
1066 opts->fs_uid = option;
1067 break;
1068 case Opt_gid:
1069 if (match_int(&args[0], &option))
1070 return 0;
1071 opts->fs_gid = option;
1072 break;
1073 case Opt_umask:
1074 if (match_octal(&args[0], &option))
1075 return 0;
1076 opts->fs_fmask = opts->fs_dmask = option;
1077 break;
1078 case Opt_dmask:
1079 if (match_octal(&args[0], &option))
1080 return 0;
1081 opts->fs_dmask = option;
1082 break;
1083 case Opt_fmask:
1084 if (match_octal(&args[0], &option))
1085 return 0;
1086 opts->fs_fmask = option;
1087 break;
1088 case Opt_allow_utime:
1089 if (match_octal(&args[0], &option))
1090 return 0;
1091 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1092 break;
1093 case Opt_codepage:
1094 if (match_int(&args[0], &option))
1095 return 0;
1096 opts->codepage = option;
1097 break;
1098 case Opt_flush:
1099 opts->flush = 1;
1100 break;
1101 case Opt_tz_utc:
1102 opts->tz_utc = 1;
1103 break;
1104 case Opt_err_cont:
1105 opts->errors = FAT_ERRORS_CONT;
1106 break;
1107 case Opt_err_panic:
1108 opts->errors = FAT_ERRORS_PANIC;
1109 break;
1110 case Opt_err_ro:
1111 opts->errors = FAT_ERRORS_RO;
1112 break;
1113
1114 /* msdos specific */
1115 case Opt_dots:
1116 opts->dotsOK = 1;
1117 break;
1118 case Opt_nodots:
1119 opts->dotsOK = 0;
1120 break;
1121
1122 /* vfat specific */
1123 case Opt_charset:
1124 if (opts->iocharset != fat_default_iocharset)
1125 kfree(opts->iocharset);
1126 iocharset = match_strdup(&args[0]);
1127 if (!iocharset)
1128 return -ENOMEM;
1129 opts->iocharset = iocharset;
1130 break;
1131 case Opt_shortname_lower:
1132 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1133 | VFAT_SFN_CREATE_WIN95;
1134 break;
1135 case Opt_shortname_win95:
1136 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1137 | VFAT_SFN_CREATE_WIN95;
1138 break;
1139 case Opt_shortname_winnt:
1140 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1141 | VFAT_SFN_CREATE_WINNT;
1142 break;
1143 case Opt_shortname_mixed:
1144 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1145 | VFAT_SFN_CREATE_WIN95;
1146 break;
1147 case Opt_utf8_no: /* 0 or no or false */
1148 opts->utf8 = 0;
1149 break;
1150 case Opt_utf8_yes: /* empty or 1 or yes or true */
1151 opts->utf8 = 1;
1152 break;
1153 case Opt_uni_xl_no: /* 0 or no or false */
1154 opts->unicode_xlate = 0;
1155 break;
1156 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1157 opts->unicode_xlate = 1;
1158 break;
1159 case Opt_nonumtail_no: /* 0 or no or false */
1160 opts->numtail = 1; /* negated option */
1161 break;
1162 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1163 opts->numtail = 0; /* negated option */
1164 break;
1165 case Opt_rodir:
1166 opts->rodir = 1;
1167 break;
1168 case Opt_discard:
1169 opts->discard = 1;
1170 break;
1171
1172 /* obsolete mount options */
1173 case Opt_obsolate:
1174 fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1175 "not supported now", p);
1176 break;
1177 /* unknown option */
1178 default:
1179 if (!silent) {
1180 fat_msg(sb, KERN_ERR,
1181 "Unrecognized mount option \"%s\" "
1182 "or missing value", p);
1183 }
1184 return -EINVAL;
1185 }
1186 }
1187
1188out:
1189 /* UTF-8 doesn't provide FAT semantics */
1190 if (!strcmp(opts->iocharset, "utf8")) {
1191 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1192 " for FAT filesystems, filesystem will be "
1193 "case sensitive!");
1194 }
1195
1196 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1197 if (opts->allow_utime == (unsigned short)-1)
1198 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1199 if (opts->unicode_xlate)
1200 opts->utf8 = 0;
1201
1202 return 0;
1203}
1204
1205static int fat_read_root(struct inode *inode)
1206{
1207 struct super_block *sb = inode->i_sb;
1208 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1209 int error;
1210
1211 MSDOS_I(inode)->i_pos = 0;
1212 inode->i_uid = sbi->options.fs_uid;
1213 inode->i_gid = sbi->options.fs_gid;
1214 inode->i_version++;
1215 inode->i_generation = 0;
1216 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1217 inode->i_op = sbi->dir_ops;
1218 inode->i_fop = &fat_dir_operations;
1219 if (sbi->fat_bits == 32) {
1220 MSDOS_I(inode)->i_start = sbi->root_cluster;
1221 error = fat_calc_dir_size(inode);
1222 if (error < 0)
1223 return error;
1224 } else {
1225 MSDOS_I(inode)->i_start = 0;
1226 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1227 }
1228 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1229 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1230 MSDOS_I(inode)->i_logstart = 0;
1231 MSDOS_I(inode)->mmu_private = inode->i_size;
1232
1233 fat_save_attrs(inode, ATTR_DIR);
1234 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1235 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1236 inode->i_nlink = fat_subdirs(inode)+2;
1237
1238 return 0;
1239}
1240
1241/*
1242 * Read the super block of an MS-DOS FS.
1243 */
1244int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1245 void (*setup)(struct super_block *))
1246{
1247 struct inode *root_inode = NULL, *fat_inode = NULL;
1248 struct buffer_head *bh;
1249 struct fat_boot_sector *b;
1250 struct msdos_sb_info *sbi;
1251 u16 logical_sector_size;
1252 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1253 int debug;
1254 unsigned int media;
1255 long error;
1256 char buf[50];
1257
1258 /*
1259 * GFP_KERNEL is ok here, because while we do hold the
1260 * supeblock lock, memory pressure can't call back into
1261 * the filesystem, since we're only just about to mount
1262 * it and have no inodes etc active!
1263 */
1264 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1265 if (!sbi)
1266 return -ENOMEM;
1267 sb->s_fs_info = sbi;
1268
1269 sb->s_flags |= MS_NODIRATIME;
1270 sb->s_magic = MSDOS_SUPER_MAGIC;
1271 sb->s_op = &fat_sops;
1272 sb->s_export_op = &fat_export_ops;
1273 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1274 DEFAULT_RATELIMIT_BURST);
1275
1276 error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1277 if (error)
1278 goto out_fail;
1279
1280 setup(sb); /* flavour-specific stuff that needs options */
1281
1282 error = -EIO;
1283 sb_min_blocksize(sb, 512);
1284 bh = sb_bread(sb, 0);
1285 if (bh == NULL) {
1286 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1287 goto out_fail;
1288 }
1289
1290 b = (struct fat_boot_sector *) bh->b_data;
1291 if (!b->reserved) {
1292 if (!silent)
1293 fat_msg(sb, KERN_ERR, "bogus number of reserved sectors");
1294 brelse(bh);
1295 goto out_invalid;
1296 }
1297 if (!b->fats) {
1298 if (!silent)
1299 fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1300 brelse(bh);
1301 goto out_invalid;
1302 }
1303
1304 /*
1305 * Earlier we checked here that b->secs_track and b->head are nonzero,
1306 * but it turns out valid FAT filesystems can have zero there.
1307 */
1308
1309 media = b->media;
1310 if (!fat_valid_media(media)) {
1311 if (!silent)
1312 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1313 media);
1314 brelse(bh);
1315 goto out_invalid;
1316 }
1317 logical_sector_size = get_unaligned_le16(&b->sector_size);
1318 if (!is_power_of_2(logical_sector_size)
1319 || (logical_sector_size < 512)
1320 || (logical_sector_size > 4096)) {
1321 if (!silent)
1322 fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1323 logical_sector_size);
1324 brelse(bh);
1325 goto out_invalid;
1326 }
1327 sbi->sec_per_clus = b->sec_per_clus;
1328 if (!is_power_of_2(sbi->sec_per_clus)) {
1329 if (!silent)
1330 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1331 sbi->sec_per_clus);
1332 brelse(bh);
1333 goto out_invalid;
1334 }
1335
1336 if (logical_sector_size < sb->s_blocksize) {
1337 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1338 " (logical sector size = %u)", logical_sector_size);
1339 brelse(bh);
1340 goto out_fail;
1341 }
1342 if (logical_sector_size > sb->s_blocksize) {
1343 brelse(bh);
1344
1345 if (!sb_set_blocksize(sb, logical_sector_size)) {
1346 fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1347 logical_sector_size);
1348 goto out_fail;
1349 }
1350 bh = sb_bread(sb, 0);
1351 if (bh == NULL) {
1352 fat_msg(sb, KERN_ERR, "unable to read boot sector"
1353 " (logical sector size = %lu)",
1354 sb->s_blocksize);
1355 goto out_fail;
1356 }
1357 b = (struct fat_boot_sector *) bh->b_data;
1358 }
1359
1360 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1361 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1362 sbi->fats = b->fats;
1363 sbi->fat_bits = 0; /* Don't know yet */
1364 sbi->fat_start = le16_to_cpu(b->reserved);
1365 sbi->fat_length = le16_to_cpu(b->fat_length);
1366 sbi->root_cluster = 0;
1367 sbi->free_clusters = -1; /* Don't know yet */
1368 sbi->free_clus_valid = 0;
1369 sbi->prev_free = FAT_START_ENT;
1370 sb->s_maxbytes = 0xffffffff;
1371
1372 if (!sbi->fat_length && b->fat32_length) {
1373 struct fat_boot_fsinfo *fsinfo;
1374 struct buffer_head *fsinfo_bh;
1375
1376 /* Must be FAT32 */
1377 sbi->fat_bits = 32;
1378 sbi->fat_length = le32_to_cpu(b->fat32_length);
1379 sbi->root_cluster = le32_to_cpu(b->root_cluster);
1380
1381 /* MC - if info_sector is 0, don't multiply by 0 */
1382 sbi->fsinfo_sector = le16_to_cpu(b->info_sector);
1383 if (sbi->fsinfo_sector == 0)
1384 sbi->fsinfo_sector = 1;
1385
1386 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1387 if (fsinfo_bh == NULL) {
1388 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1389 " (sector = %lu)", sbi->fsinfo_sector);
1390 brelse(bh);
1391 goto out_fail;
1392 }
1393
1394 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1395 if (!IS_FSINFO(fsinfo)) {
1396 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1397 "0x%08x, 0x%08x (sector = %lu)",
1398 le32_to_cpu(fsinfo->signature1),
1399 le32_to_cpu(fsinfo->signature2),
1400 sbi->fsinfo_sector);
1401 } else {
1402 if (sbi->options.usefree)
1403 sbi->free_clus_valid = 1;
1404 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1405 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1406 }
1407
1408 brelse(fsinfo_bh);
1409 }
1410
1411 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1412 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1413
1414 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1415 sbi->dir_entries = get_unaligned_le16(&b->dir_entries);
1416 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1417 if (!silent)
1418 fat_msg(sb, KERN_ERR, "bogus directroy-entries per block"
1419 " (%u)", sbi->dir_entries);
1420 brelse(bh);
1421 goto out_invalid;
1422 }
1423
1424 rootdir_sectors = sbi->dir_entries
1425 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1426 sbi->data_start = sbi->dir_start + rootdir_sectors;
1427 total_sectors = get_unaligned_le16(&b->sectors);
1428 if (total_sectors == 0)
1429 total_sectors = le32_to_cpu(b->total_sect);
1430
1431 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1432
1433 if (sbi->fat_bits != 32)
1434 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1435
1436 /* check that FAT table does not overflow */
1437 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1438 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1439 if (total_clusters > MAX_FAT(sb)) {
1440 if (!silent)
1441 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1442 total_clusters);
1443 brelse(bh);
1444 goto out_invalid;
1445 }
1446
1447 sbi->max_cluster = total_clusters + FAT_START_ENT;
1448 /* check the free_clusters, it's not necessarily correct */
1449 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1450 sbi->free_clusters = -1;
1451 /* check the prev_free, it's not necessarily correct */
1452 sbi->prev_free %= sbi->max_cluster;
1453 if (sbi->prev_free < FAT_START_ENT)
1454 sbi->prev_free = FAT_START_ENT;
1455
1456 brelse(bh);
1457
1458 /* set up enough so that it can read an inode */
1459 fat_hash_init(sb);
1460 fat_ent_access_init(sb);
1461
1462 /*
1463 * The low byte of FAT's first entry must have same value with
1464 * media-field. But in real world, too many devices is
1465 * writing wrong value. So, removed that validity check.
1466 *
1467 * if (FAT_FIRST_ENT(sb, media) != first)
1468 */
1469
1470 error = -EINVAL;
1471 sprintf(buf, "cp%d", sbi->options.codepage);
1472 sbi->nls_disk = load_nls(buf);
1473 if (!sbi->nls_disk) {
1474 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1475 goto out_fail;
1476 }
1477
1478 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1479 if (sbi->options.isvfat) {
1480 sbi->nls_io = load_nls(sbi->options.iocharset);
1481 if (!sbi->nls_io) {
1482 fat_msg(sb, KERN_ERR, "IO charset %s not found",
1483 sbi->options.iocharset);
1484 goto out_fail;
1485 }
1486 }
1487
1488 error = -ENOMEM;
1489 fat_inode = new_inode(sb);
1490 if (!fat_inode)
1491 goto out_fail;
1492 MSDOS_I(fat_inode)->i_pos = 0;
1493 sbi->fat_inode = fat_inode;
1494 root_inode = new_inode(sb);
1495 if (!root_inode)
1496 goto out_fail;
1497 root_inode->i_ino = MSDOS_ROOT_INO;
1498 root_inode->i_version = 1;
1499 error = fat_read_root(root_inode);
1500 if (error < 0)
1501 goto out_fail;
1502 error = -ENOMEM;
1503 insert_inode_hash(root_inode);
1504 sb->s_root = d_alloc_root(root_inode);
1505 if (!sb->s_root) {
1506 fat_msg(sb, KERN_ERR, "get root inode failed");
1507 goto out_fail;
1508 }
1509
1510 return 0;
1511
1512out_invalid:
1513 error = -EINVAL;
1514 if (!silent)
1515 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1516
1517out_fail:
1518 if (fat_inode)
1519 iput(fat_inode);
1520 if (root_inode)
1521 iput(root_inode);
1522 unload_nls(sbi->nls_io);
1523 unload_nls(sbi->nls_disk);
1524 if (sbi->options.iocharset != fat_default_iocharset)
1525 kfree(sbi->options.iocharset);
1526 sb->s_fs_info = NULL;
1527 kfree(sbi);
1528 return error;
1529}
1530
1531EXPORT_SYMBOL_GPL(fat_fill_super);
1532
1533/*
1534 * helper function for fat_flush_inodes. This writes both the inode
1535 * and the file data blocks, waiting for in flight data blocks before
1536 * the start of the call. It does not wait for any io started
1537 * during the call
1538 */
1539static int writeback_inode(struct inode *inode)
1540{
1541
1542 int ret;
1543 struct address_space *mapping = inode->i_mapping;
1544 struct writeback_control wbc = {
1545 .sync_mode = WB_SYNC_NONE,
1546 .nr_to_write = 0,
1547 };
1548 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the
1549 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode
1550 * and filemap_fdatawrite is used for the data blocks
1551 */
1552 ret = sync_inode(inode, &wbc);
1553 if (!ret)
1554 ret = filemap_fdatawrite(mapping);
1555 return ret;
1556}
1557
1558/*
1559 * write data and metadata corresponding to i1 and i2. The io is
1560 * started but we do not wait for any of it to finish.
1561 *
1562 * filemap_flush is used for the block device, so if there is a dirty
1563 * page for a block already in flight, we will not wait and start the
1564 * io over again
1565 */
1566int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1567{
1568 int ret = 0;
1569 if (!MSDOS_SB(sb)->options.flush)
1570 return 0;
1571 if (i1)
1572 ret = writeback_inode(i1);
1573 if (!ret && i2)
1574 ret = writeback_inode(i2);
1575 if (!ret) {
1576 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1577 ret = filemap_flush(mapping);
1578 }
1579 return ret;
1580}
1581EXPORT_SYMBOL_GPL(fat_flush_inodes);
1582
1583static int __init init_fat_fs(void)
1584{
1585 int err;
1586
1587 err = fat_cache_init();
1588 if (err)
1589 return err;
1590
1591 err = fat_init_inodecache();
1592 if (err)
1593 goto failed;
1594
1595 return 0;
1596
1597failed:
1598 fat_cache_destroy();
1599 return err;
1600}
1601
1602static void __exit exit_fat_fs(void)
1603{
1604 fat_cache_destroy();
1605 fat_destroy_inodecache();
1606}
1607
1608module_init(init_fat_fs)
1609module_exit(exit_fat_fs)
1610
1611MODULE_LICENSE("GPL");
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/uio.h>
20#include <linux/blkdev.h>
21#include <linux/backing-dev.h>
22#include <linux/unaligned.h>
23#include <linux/random.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 */
43struct 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
63static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
64static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
65
66static 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
103int 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
118static 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
182static 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
196static int fat_writepages(struct address_space *mapping,
197 struct writeback_control *wbc)
198{
199 return mpage_writepages(mapping, wbc, fat_get_block);
200}
201
202static int fat_read_folio(struct file *file, struct folio *folio)
203{
204 return mpage_read_folio(folio, fat_get_block);
205}
206
207static void fat_readahead(struct readahead_control *rac)
208{
209 mpage_readahead(rac, fat_get_block);
210}
211
212static 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
222static int fat_write_begin(struct file *file, struct address_space *mapping,
223 loff_t pos, unsigned len,
224 struct folio **foliop, void **fsdata)
225{
226 int err;
227
228 err = cont_write_begin(file, mapping, pos, len,
229 foliop, fsdata, fat_get_block,
230 &MSDOS_I(mapping->host)->mmu_private);
231 if (err < 0)
232 fat_write_failed(mapping, pos + len);
233 return err;
234}
235
236static int fat_write_end(struct file *file, struct address_space *mapping,
237 loff_t pos, unsigned len, unsigned copied,
238 struct folio *folio, void *fsdata)
239{
240 struct inode *inode = mapping->host;
241 int err;
242 err = generic_write_end(file, mapping, pos, len, copied, folio, fsdata);
243 if (err < len)
244 fat_write_failed(mapping, pos + len);
245 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
246 fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
247 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
248 mark_inode_dirty(inode);
249 }
250 return err;
251}
252
253static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
254{
255 struct file *file = iocb->ki_filp;
256 struct address_space *mapping = file->f_mapping;
257 struct inode *inode = mapping->host;
258 size_t count = iov_iter_count(iter);
259 loff_t offset = iocb->ki_pos;
260 ssize_t ret;
261
262 if (iov_iter_rw(iter) == WRITE) {
263 /*
264 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
265 * so we need to update the ->mmu_private to block boundary.
266 *
267 * But we must fill the remaining area or hole by nul for
268 * updating ->mmu_private.
269 *
270 * Return 0, and fallback to normal buffered write.
271 */
272 loff_t size = offset + count;
273 if (MSDOS_I(inode)->mmu_private < size)
274 return 0;
275 }
276
277 /*
278 * FAT need to use the DIO_LOCKING for avoiding the race
279 * condition of fat_get_block() and ->truncate().
280 */
281 ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
282 if (ret < 0 && iov_iter_rw(iter) == WRITE)
283 fat_write_failed(mapping, offset + count);
284
285 return ret;
286}
287
288static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
289 struct buffer_head *bh_result, int create)
290{
291 struct super_block *sb = inode->i_sb;
292 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
293 int err;
294 sector_t bmap;
295 unsigned long mapped_blocks;
296
297 BUG_ON(create != 0);
298
299 err = fat_bmap(inode, iblock, &bmap, &mapped_blocks, create, true);
300 if (err)
301 return err;
302
303 if (bmap) {
304 map_bh(bh_result, sb, bmap);
305 max_blocks = min(mapped_blocks, max_blocks);
306 }
307
308 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
309
310 return 0;
311}
312
313static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
314{
315 sector_t blocknr;
316
317 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
318 down_read(&MSDOS_I(mapping->host)->truncate_lock);
319 blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
320 up_read(&MSDOS_I(mapping->host)->truncate_lock);
321
322 return blocknr;
323}
324
325/*
326 * fat_block_truncate_page() zeroes out a mapping from file offset `from'
327 * up to the end of the block which corresponds to `from'.
328 * This is required during truncate to physically zeroout the tail end
329 * of that block so it doesn't yield old data if the file is later grown.
330 * Also, avoid causing failure from fsx for cases of "data past EOF"
331 */
332int fat_block_truncate_page(struct inode *inode, loff_t from)
333{
334 return block_truncate_page(inode->i_mapping, from, fat_get_block);
335}
336
337static const struct address_space_operations fat_aops = {
338 .dirty_folio = block_dirty_folio,
339 .invalidate_folio = block_invalidate_folio,
340 .read_folio = fat_read_folio,
341 .readahead = fat_readahead,
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 .migrate_folio = buffer_migrate_folio,
348};
349
350/*
351 * New FAT inode stuff. We do the following:
352 * a) i_ino is constant and has nothing with on-disk location.
353 * b) FAT manages its own cache of directory entries.
354 * c) *This* cache is indexed by on-disk location.
355 * d) inode has an associated directory entry, all right, but
356 * it may be unhashed.
357 * e) currently entries are stored within struct inode. That should
358 * change.
359 * f) we deal with races in the following way:
360 * 1. readdir() and lookup() do FAT-dir-cache lookup.
361 * 2. rename() unhashes the F-d-c entry and rehashes it in
362 * a new place.
363 * 3. unlink() and rmdir() unhash F-d-c entry.
364 * 4. fat_write_inode() checks whether the thing is unhashed.
365 * If it is we silently return. If it isn't we do bread(),
366 * check if the location is still valid and retry if it
367 * isn't. Otherwise we do changes.
368 * 5. Spinlock is used to protect hash/unhash/location check/lookup
369 * 6. fat_evict_inode() unhashes the F-d-c entry.
370 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
371 * and consider negative result as cache miss.
372 */
373
374static void fat_hash_init(struct super_block *sb)
375{
376 struct msdos_sb_info *sbi = MSDOS_SB(sb);
377 int i;
378
379 spin_lock_init(&sbi->inode_hash_lock);
380 for (i = 0; i < FAT_HASH_SIZE; i++)
381 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
382}
383
384static inline unsigned long fat_hash(loff_t i_pos)
385{
386 return hash_32(i_pos, FAT_HASH_BITS);
387}
388
389static void dir_hash_init(struct super_block *sb)
390{
391 struct msdos_sb_info *sbi = MSDOS_SB(sb);
392 int i;
393
394 spin_lock_init(&sbi->dir_hash_lock);
395 for (i = 0; i < FAT_HASH_SIZE; i++)
396 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
397}
398
399void fat_attach(struct inode *inode, loff_t i_pos)
400{
401 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
402
403 if (inode->i_ino != MSDOS_ROOT_INO) {
404 struct hlist_head *head = sbi->inode_hashtable
405 + fat_hash(i_pos);
406
407 spin_lock(&sbi->inode_hash_lock);
408 MSDOS_I(inode)->i_pos = i_pos;
409 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
410 spin_unlock(&sbi->inode_hash_lock);
411 }
412
413 /* If NFS support is enabled, cache the mapping of start cluster
414 * to directory inode. This is used during reconnection of
415 * dentries to the filesystem root.
416 */
417 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
418 struct hlist_head *d_head = sbi->dir_hashtable;
419 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
420
421 spin_lock(&sbi->dir_hash_lock);
422 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
423 spin_unlock(&sbi->dir_hash_lock);
424 }
425}
426EXPORT_SYMBOL_GPL(fat_attach);
427
428void fat_detach(struct inode *inode)
429{
430 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
431 spin_lock(&sbi->inode_hash_lock);
432 MSDOS_I(inode)->i_pos = 0;
433 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
434 spin_unlock(&sbi->inode_hash_lock);
435
436 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
437 spin_lock(&sbi->dir_hash_lock);
438 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
439 spin_unlock(&sbi->dir_hash_lock);
440 }
441}
442EXPORT_SYMBOL_GPL(fat_detach);
443
444struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
445{
446 struct msdos_sb_info *sbi = MSDOS_SB(sb);
447 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
448 struct msdos_inode_info *i;
449 struct inode *inode = NULL;
450
451 spin_lock(&sbi->inode_hash_lock);
452 hlist_for_each_entry(i, head, i_fat_hash) {
453 BUG_ON(i->vfs_inode.i_sb != sb);
454 if (i->i_pos != i_pos)
455 continue;
456 inode = igrab(&i->vfs_inode);
457 if (inode)
458 break;
459 }
460 spin_unlock(&sbi->inode_hash_lock);
461 return inode;
462}
463
464static int is_exec(unsigned char *extension)
465{
466 unsigned char exe_extensions[] = "EXECOMBAT", *walk;
467
468 for (walk = exe_extensions; *walk; walk += 3)
469 if (!strncmp(extension, walk, 3))
470 return 1;
471 return 0;
472}
473
474static int fat_calc_dir_size(struct inode *inode)
475{
476 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
477 int ret, fclus, dclus;
478
479 inode->i_size = 0;
480 if (MSDOS_I(inode)->i_start == 0)
481 return 0;
482
483 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
484 if (ret < 0)
485 return ret;
486 inode->i_size = (fclus + 1) << sbi->cluster_bits;
487
488 return 0;
489}
490
491static int fat_validate_dir(struct inode *dir)
492{
493 struct super_block *sb = dir->i_sb;
494
495 if (dir->i_nlink < 2) {
496 /* Directory should have "."/".." entries at least. */
497 fat_fs_error(sb, "corrupted directory (invalid entries)");
498 return -EIO;
499 }
500 if (MSDOS_I(dir)->i_start == 0 ||
501 MSDOS_I(dir)->i_start == MSDOS_SB(sb)->root_cluster) {
502 /* Directory should point valid cluster. */
503 fat_fs_error(sb, "corrupted directory (invalid i_start)");
504 return -EIO;
505 }
506 return 0;
507}
508
509/* doesn't deal with root inode */
510int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
511{
512 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
513 struct timespec64 mtime;
514 int error;
515
516 MSDOS_I(inode)->i_pos = 0;
517 inode->i_uid = sbi->options.fs_uid;
518 inode->i_gid = sbi->options.fs_gid;
519 inode_inc_iversion(inode);
520 inode->i_generation = get_random_u32();
521
522 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
523 inode->i_generation &= ~1;
524 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
525 inode->i_op = sbi->dir_ops;
526 inode->i_fop = &fat_dir_operations;
527
528 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
529 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
530 error = fat_calc_dir_size(inode);
531 if (error < 0)
532 return error;
533 MSDOS_I(inode)->mmu_private = inode->i_size;
534
535 set_nlink(inode, fat_subdirs(inode));
536
537 error = fat_validate_dir(inode);
538 if (error < 0)
539 return error;
540 } else { /* not a directory */
541 inode->i_generation |= 1;
542 inode->i_mode = fat_make_mode(sbi, de->attr,
543 ((sbi->options.showexec && !is_exec(de->name + 8))
544 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
545 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
546
547 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
548 inode->i_size = le32_to_cpu(de->size);
549 inode->i_op = &fat_file_inode_operations;
550 inode->i_fop = &fat_file_operations;
551 inode->i_mapping->a_ops = &fat_aops;
552 MSDOS_I(inode)->mmu_private = inode->i_size;
553 }
554 if (de->attr & ATTR_SYS) {
555 if (sbi->options.sys_immutable)
556 inode->i_flags |= S_IMMUTABLE;
557 }
558 fat_save_attrs(inode, de->attr);
559
560 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
561 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
562
563 fat_time_fat2unix(sbi, &mtime, de->time, de->date, 0);
564 inode_set_mtime_to_ts(inode, mtime);
565 inode_set_ctime_to_ts(inode, mtime);
566 if (sbi->options.isvfat) {
567 struct timespec64 atime;
568
569 fat_time_fat2unix(sbi, &atime, 0, de->adate, 0);
570 inode_set_atime_to_ts(inode, atime);
571 fat_time_fat2unix(sbi, &MSDOS_I(inode)->i_crtime, de->ctime,
572 de->cdate, de->ctime_cs);
573 } else
574 inode_set_atime_to_ts(inode, fat_truncate_atime(sbi, &mtime));
575
576 return 0;
577}
578
579static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
580{
581 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
582 mutex_lock(&sbi->nfs_build_inode_lock);
583}
584
585static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
586{
587 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
588 mutex_unlock(&sbi->nfs_build_inode_lock);
589}
590
591struct inode *fat_build_inode(struct super_block *sb,
592 struct msdos_dir_entry *de, loff_t i_pos)
593{
594 struct inode *inode;
595 int err;
596
597 fat_lock_build_inode(MSDOS_SB(sb));
598 inode = fat_iget(sb, i_pos);
599 if (inode)
600 goto out;
601 inode = new_inode(sb);
602 if (!inode) {
603 inode = ERR_PTR(-ENOMEM);
604 goto out;
605 }
606 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
607 inode_set_iversion(inode, 1);
608 err = fat_fill_inode(inode, de);
609 if (err) {
610 iput(inode);
611 inode = ERR_PTR(err);
612 goto out;
613 }
614 fat_attach(inode, i_pos);
615 insert_inode_hash(inode);
616out:
617 fat_unlock_build_inode(MSDOS_SB(sb));
618 return inode;
619}
620
621EXPORT_SYMBOL_GPL(fat_build_inode);
622
623static int __fat_write_inode(struct inode *inode, int wait);
624
625static void fat_free_eofblocks(struct inode *inode)
626{
627 /* Release unwritten fallocated blocks on inode eviction. */
628 if ((inode->i_blocks << 9) >
629 round_up(MSDOS_I(inode)->mmu_private,
630 MSDOS_SB(inode->i_sb)->cluster_size)) {
631 int err;
632
633 fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
634 /* Fallocate results in updating the i_start/iogstart
635 * for the zero byte file. So, make it return to
636 * original state during evict and commit it to avoid
637 * any corruption on the next access to the cluster
638 * chain for the file.
639 */
640 err = __fat_write_inode(inode, inode_needs_sync(inode));
641 if (err) {
642 fat_msg(inode->i_sb, KERN_WARNING, "Failed to "
643 "update on disk inode for unused "
644 "fallocated blocks, inode could be "
645 "corrupted. Please run fsck");
646 }
647
648 }
649}
650
651static void fat_evict_inode(struct inode *inode)
652{
653 truncate_inode_pages_final(&inode->i_data);
654 if (!inode->i_nlink) {
655 inode->i_size = 0;
656 fat_truncate_blocks(inode, 0);
657 } else
658 fat_free_eofblocks(inode);
659
660 invalidate_inode_buffers(inode);
661 clear_inode(inode);
662 fat_cache_inval_inode(inode);
663 fat_detach(inode);
664}
665
666static void fat_set_state(struct super_block *sb,
667 unsigned int set, unsigned int force)
668{
669 struct buffer_head *bh;
670 struct fat_boot_sector *b;
671 struct msdos_sb_info *sbi = MSDOS_SB(sb);
672
673 /* do not change any thing if mounted read only */
674 if (sb_rdonly(sb) && !force)
675 return;
676
677 /* do not change state if fs was dirty */
678 if (sbi->dirty) {
679 /* warn only on set (mount). */
680 if (set)
681 fat_msg(sb, KERN_WARNING, "Volume was not properly "
682 "unmounted. Some data may be corrupt. "
683 "Please run fsck.");
684 return;
685 }
686
687 bh = sb_bread(sb, 0);
688 if (bh == NULL) {
689 fat_msg(sb, KERN_ERR, "unable to read boot sector "
690 "to mark fs as dirty");
691 return;
692 }
693
694 b = (struct fat_boot_sector *) bh->b_data;
695
696 if (is_fat32(sbi)) {
697 if (set)
698 b->fat32.state |= FAT_STATE_DIRTY;
699 else
700 b->fat32.state &= ~FAT_STATE_DIRTY;
701 } else /* fat 16 and 12 */ {
702 if (set)
703 b->fat16.state |= FAT_STATE_DIRTY;
704 else
705 b->fat16.state &= ~FAT_STATE_DIRTY;
706 }
707
708 mark_buffer_dirty(bh);
709 sync_dirty_buffer(bh);
710 brelse(bh);
711}
712
713static void fat_reset_iocharset(struct fat_mount_options *opts)
714{
715 if (opts->iocharset != fat_default_iocharset) {
716 /* Note: opts->iocharset can be NULL here */
717 kfree(opts->iocharset);
718 opts->iocharset = fat_default_iocharset;
719 }
720}
721
722static void delayed_free(struct rcu_head *p)
723{
724 struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
725 unload_nls(sbi->nls_disk);
726 unload_nls(sbi->nls_io);
727 fat_reset_iocharset(&sbi->options);
728 kfree(sbi);
729}
730
731static void fat_put_super(struct super_block *sb)
732{
733 struct msdos_sb_info *sbi = MSDOS_SB(sb);
734
735 fat_set_state(sb, 0, 0);
736
737 iput(sbi->fsinfo_inode);
738 iput(sbi->fat_inode);
739
740 call_rcu(&sbi->rcu, delayed_free);
741}
742
743static struct kmem_cache *fat_inode_cachep;
744
745static struct inode *fat_alloc_inode(struct super_block *sb)
746{
747 struct msdos_inode_info *ei;
748 ei = alloc_inode_sb(sb, fat_inode_cachep, GFP_NOFS);
749 if (!ei)
750 return NULL;
751
752 init_rwsem(&ei->truncate_lock);
753 /* Zeroing to allow iput() even if partial initialized inode. */
754 ei->mmu_private = 0;
755 ei->i_start = 0;
756 ei->i_logstart = 0;
757 ei->i_attrs = 0;
758 ei->i_pos = 0;
759 ei->i_crtime.tv_sec = 0;
760 ei->i_crtime.tv_nsec = 0;
761
762 return &ei->vfs_inode;
763}
764
765static void fat_free_inode(struct inode *inode)
766{
767 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
768}
769
770static void init_once(void *foo)
771{
772 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
773
774 spin_lock_init(&ei->cache_lru_lock);
775 ei->nr_caches = 0;
776 ei->cache_valid_id = FAT_CACHE_VALID + 1;
777 INIT_LIST_HEAD(&ei->cache_lru);
778 INIT_HLIST_NODE(&ei->i_fat_hash);
779 INIT_HLIST_NODE(&ei->i_dir_hash);
780 inode_init_once(&ei->vfs_inode);
781}
782
783static int __init fat_init_inodecache(void)
784{
785 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
786 sizeof(struct msdos_inode_info),
787 0, (SLAB_RECLAIM_ACCOUNT|
788 SLAB_ACCOUNT),
789 init_once);
790 if (fat_inode_cachep == NULL)
791 return -ENOMEM;
792 return 0;
793}
794
795static void __exit fat_destroy_inodecache(void)
796{
797 /*
798 * Make sure all delayed rcu free inodes are flushed before we
799 * destroy cache.
800 */
801 rcu_barrier();
802 kmem_cache_destroy(fat_inode_cachep);
803}
804
805int fat_reconfigure(struct fs_context *fc)
806{
807 bool new_rdonly;
808 struct super_block *sb = fc->root->d_sb;
809 struct msdos_sb_info *sbi = MSDOS_SB(sb);
810 fc->sb_flags |= SB_NODIRATIME | (sbi->options.isvfat ? 0 : SB_NOATIME);
811
812 sync_filesystem(sb);
813
814 /* make sure we update state on remount. */
815 new_rdonly = fc->sb_flags & SB_RDONLY;
816 if (new_rdonly != sb_rdonly(sb)) {
817 if (new_rdonly)
818 fat_set_state(sb, 0, 0);
819 else
820 fat_set_state(sb, 1, 1);
821 }
822 return 0;
823}
824EXPORT_SYMBOL_GPL(fat_reconfigure);
825
826static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
827{
828 struct super_block *sb = dentry->d_sb;
829 struct msdos_sb_info *sbi = MSDOS_SB(sb);
830 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
831
832 /* If the count of free cluster is still unknown, counts it here. */
833 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
834 int err = fat_count_free_clusters(dentry->d_sb);
835 if (err)
836 return err;
837 }
838
839 buf->f_type = dentry->d_sb->s_magic;
840 buf->f_bsize = sbi->cluster_size;
841 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
842 buf->f_bfree = sbi->free_clusters;
843 buf->f_bavail = sbi->free_clusters;
844 buf->f_fsid = u64_to_fsid(id);
845 buf->f_namelen =
846 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
847
848 return 0;
849}
850
851static int __fat_write_inode(struct inode *inode, int wait)
852{
853 struct super_block *sb = inode->i_sb;
854 struct msdos_sb_info *sbi = MSDOS_SB(sb);
855 struct buffer_head *bh;
856 struct msdos_dir_entry *raw_entry;
857 struct timespec64 mtime;
858 loff_t i_pos;
859 sector_t blocknr;
860 int err, offset;
861
862 if (inode->i_ino == MSDOS_ROOT_INO)
863 return 0;
864
865retry:
866 i_pos = fat_i_pos_read(sbi, inode);
867 if (!i_pos)
868 return 0;
869
870 fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
871 bh = sb_bread(sb, blocknr);
872 if (!bh) {
873 fat_msg(sb, KERN_ERR, "unable to read inode block "
874 "for updating (i_pos %lld)", i_pos);
875 return -EIO;
876 }
877 spin_lock(&sbi->inode_hash_lock);
878 if (i_pos != MSDOS_I(inode)->i_pos) {
879 spin_unlock(&sbi->inode_hash_lock);
880 brelse(bh);
881 goto retry;
882 }
883
884 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
885 if (S_ISDIR(inode->i_mode))
886 raw_entry->size = 0;
887 else
888 raw_entry->size = cpu_to_le32(inode->i_size);
889 raw_entry->attr = fat_make_attrs(inode);
890 fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
891 mtime = inode_get_mtime(inode);
892 fat_time_unix2fat(sbi, &mtime, &raw_entry->time,
893 &raw_entry->date, NULL);
894 if (sbi->options.isvfat) {
895 struct timespec64 ts = inode_get_atime(inode);
896 __le16 atime;
897
898 fat_time_unix2fat(sbi, &ts, &atime, &raw_entry->adate, NULL);
899 fat_time_unix2fat(sbi, &MSDOS_I(inode)->i_crtime, &raw_entry->ctime,
900 &raw_entry->cdate, &raw_entry->ctime_cs);
901 }
902 spin_unlock(&sbi->inode_hash_lock);
903 mark_buffer_dirty(bh);
904 err = 0;
905 if (wait)
906 err = sync_dirty_buffer(bh);
907 brelse(bh);
908 return err;
909}
910
911static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
912{
913 int err;
914
915 if (inode->i_ino == MSDOS_FSINFO_INO) {
916 struct super_block *sb = inode->i_sb;
917
918 mutex_lock(&MSDOS_SB(sb)->s_lock);
919 err = fat_clusters_flush(sb);
920 mutex_unlock(&MSDOS_SB(sb)->s_lock);
921 } else
922 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
923
924 return err;
925}
926
927int fat_sync_inode(struct inode *inode)
928{
929 return __fat_write_inode(inode, 1);
930}
931
932EXPORT_SYMBOL_GPL(fat_sync_inode);
933
934static int fat_show_options(struct seq_file *m, struct dentry *root);
935static const struct super_operations fat_sops = {
936 .alloc_inode = fat_alloc_inode,
937 .free_inode = fat_free_inode,
938 .write_inode = fat_write_inode,
939 .evict_inode = fat_evict_inode,
940 .put_super = fat_put_super,
941 .statfs = fat_statfs,
942 .show_options = fat_show_options,
943};
944
945static int fat_show_options(struct seq_file *m, struct dentry *root)
946{
947 struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
948 struct fat_mount_options *opts = &sbi->options;
949 int isvfat = opts->isvfat;
950
951 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
952 seq_printf(m, ",uid=%u",
953 from_kuid_munged(&init_user_ns, opts->fs_uid));
954 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
955 seq_printf(m, ",gid=%u",
956 from_kgid_munged(&init_user_ns, opts->fs_gid));
957 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
958 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
959 if (opts->allow_utime)
960 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
961 if (sbi->nls_disk)
962 /* strip "cp" prefix from displayed option */
963 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
964 if (isvfat) {
965 if (sbi->nls_io)
966 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
967
968 switch (opts->shortname) {
969 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
970 seq_puts(m, ",shortname=win95");
971 break;
972 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
973 seq_puts(m, ",shortname=winnt");
974 break;
975 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
976 seq_puts(m, ",shortname=mixed");
977 break;
978 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
979 seq_puts(m, ",shortname=lower");
980 break;
981 default:
982 seq_puts(m, ",shortname=unknown");
983 break;
984 }
985 }
986 if (opts->name_check != 'n')
987 seq_printf(m, ",check=%c", opts->name_check);
988 if (opts->usefree)
989 seq_puts(m, ",usefree");
990 if (opts->quiet)
991 seq_puts(m, ",quiet");
992 if (opts->showexec)
993 seq_puts(m, ",showexec");
994 if (opts->sys_immutable)
995 seq_puts(m, ",sys_immutable");
996 if (!isvfat) {
997 if (opts->dotsOK)
998 seq_puts(m, ",dotsOK=yes");
999 if (opts->nocase)
1000 seq_puts(m, ",nocase");
1001 } else {
1002 if (opts->utf8)
1003 seq_puts(m, ",utf8");
1004 if (opts->unicode_xlate)
1005 seq_puts(m, ",uni_xlate");
1006 if (!opts->numtail)
1007 seq_puts(m, ",nonumtail");
1008 if (opts->rodir)
1009 seq_puts(m, ",rodir");
1010 }
1011 if (opts->flush)
1012 seq_puts(m, ",flush");
1013 if (opts->tz_set) {
1014 if (opts->time_offset)
1015 seq_printf(m, ",time_offset=%d", opts->time_offset);
1016 else
1017 seq_puts(m, ",tz=UTC");
1018 }
1019 if (opts->errors == FAT_ERRORS_CONT)
1020 seq_puts(m, ",errors=continue");
1021 else if (opts->errors == FAT_ERRORS_PANIC)
1022 seq_puts(m, ",errors=panic");
1023 else
1024 seq_puts(m, ",errors=remount-ro");
1025 if (opts->nfs == FAT_NFS_NOSTALE_RO)
1026 seq_puts(m, ",nfs=nostale_ro");
1027 else if (opts->nfs)
1028 seq_puts(m, ",nfs=stale_rw");
1029 if (opts->discard)
1030 seq_puts(m, ",discard");
1031 if (opts->dos1xfloppy)
1032 seq_puts(m, ",dos1xfloppy");
1033
1034 return 0;
1035}
1036
1037enum {
1038 Opt_check, Opt_uid, Opt_gid, Opt_umask, Opt_dmask, Opt_fmask,
1039 Opt_allow_utime, Opt_codepage, Opt_usefree, Opt_nocase, Opt_quiet,
1040 Opt_showexec, Opt_debug, Opt_immutable, Opt_dots, Opt_dotsOK,
1041 Opt_charset, Opt_shortname, Opt_utf8, Opt_utf8_bool,
1042 Opt_uni_xl, Opt_uni_xl_bool, Opt_nonumtail, Opt_nonumtail_bool,
1043 Opt_obsolete, Opt_flush, Opt_tz, Opt_rodir, Opt_errors, Opt_discard,
1044 Opt_nfs, Opt_nfs_enum, Opt_time_offset, Opt_dos1xfloppy,
1045};
1046
1047static const struct constant_table fat_param_check[] = {
1048 {"relaxed", 'r'},
1049 {"r", 'r'},
1050 {"strict", 's'},
1051 {"s", 's'},
1052 {"normal", 'n'},
1053 {"n", 'n'},
1054 {}
1055};
1056
1057static const struct constant_table fat_param_tz[] = {
1058 {"UTC", 0},
1059 {}
1060};
1061
1062static const struct constant_table fat_param_errors[] = {
1063 {"continue", FAT_ERRORS_CONT},
1064 {"panic", FAT_ERRORS_PANIC},
1065 {"remount-ro", FAT_ERRORS_RO},
1066 {}
1067};
1068
1069
1070static const struct constant_table fat_param_nfs[] = {
1071 {"stale_rw", FAT_NFS_STALE_RW},
1072 {"nostale_ro", FAT_NFS_NOSTALE_RO},
1073 {}
1074};
1075
1076/*
1077 * These are all obsolete but we still reject invalid options.
1078 * The corresponding values are therefore meaningless.
1079 */
1080static const struct constant_table fat_param_conv[] = {
1081 {"binary", 0},
1082 {"text", 0},
1083 {"auto", 0},
1084 {"b", 0},
1085 {"t", 0},
1086 {"a", 0},
1087 {}
1088};
1089
1090/* Core options. See below for vfat and msdos extras */
1091const struct fs_parameter_spec fat_param_spec[] = {
1092 fsparam_enum ("check", Opt_check, fat_param_check),
1093 fsparam_uid ("uid", Opt_uid),
1094 fsparam_gid ("gid", Opt_gid),
1095 fsparam_u32oct ("umask", Opt_umask),
1096 fsparam_u32oct ("dmask", Opt_dmask),
1097 fsparam_u32oct ("fmask", Opt_fmask),
1098 fsparam_u32oct ("allow_utime", Opt_allow_utime),
1099 fsparam_u32 ("codepage", Opt_codepage),
1100 fsparam_flag ("usefree", Opt_usefree),
1101 fsparam_flag ("nocase", Opt_nocase),
1102 fsparam_flag ("quiet", Opt_quiet),
1103 fsparam_flag ("showexec", Opt_showexec),
1104 fsparam_flag ("debug", Opt_debug),
1105 fsparam_flag ("sys_immutable", Opt_immutable),
1106 fsparam_flag ("flush", Opt_flush),
1107 fsparam_enum ("tz", Opt_tz, fat_param_tz),
1108 fsparam_s32 ("time_offset", Opt_time_offset),
1109 fsparam_enum ("errors", Opt_errors, fat_param_errors),
1110 fsparam_flag ("discard", Opt_discard),
1111 fsparam_flag ("nfs", Opt_nfs),
1112 fsparam_enum ("nfs", Opt_nfs_enum, fat_param_nfs),
1113 fsparam_flag ("dos1xfloppy", Opt_dos1xfloppy),
1114 __fsparam(fs_param_is_enum, "conv",
1115 Opt_obsolete, fs_param_deprecated, fat_param_conv),
1116 __fsparam(fs_param_is_u32, "fat",
1117 Opt_obsolete, fs_param_deprecated, NULL),
1118 __fsparam(fs_param_is_u32, "blocksize",
1119 Opt_obsolete, fs_param_deprecated, NULL),
1120 __fsparam(fs_param_is_string, "cvf_format",
1121 Opt_obsolete, fs_param_deprecated, NULL),
1122 __fsparam(fs_param_is_string, "cvf_options",
1123 Opt_obsolete, fs_param_deprecated, NULL),
1124 __fsparam(NULL, "posix",
1125 Opt_obsolete, fs_param_deprecated, NULL),
1126 {}
1127};
1128EXPORT_SYMBOL_GPL(fat_param_spec);
1129
1130static const struct fs_parameter_spec msdos_param_spec[] = {
1131 fsparam_flag_no ("dots", Opt_dots),
1132 fsparam_bool ("dotsOK", Opt_dotsOK),
1133 {}
1134};
1135
1136static const struct constant_table fat_param_shortname[] = {
1137 {"lower", VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95},
1138 {"win95", VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95},
1139 {"winnt", VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT},
1140 {"mixed", VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95},
1141 {}
1142};
1143
1144static const struct fs_parameter_spec vfat_param_spec[] = {
1145 fsparam_string ("iocharset", Opt_charset),
1146 fsparam_enum ("shortname", Opt_shortname, fat_param_shortname),
1147 fsparam_flag ("utf8", Opt_utf8),
1148 fsparam_bool ("utf8", Opt_utf8_bool),
1149 fsparam_flag ("uni_xlate", Opt_uni_xl),
1150 fsparam_bool ("uni_xlate", Opt_uni_xl_bool),
1151 fsparam_flag ("nonumtail", Opt_nonumtail),
1152 fsparam_bool ("nonumtail", Opt_nonumtail_bool),
1153 fsparam_flag ("rodir", Opt_rodir),
1154 {}
1155};
1156
1157int fat_parse_param(struct fs_context *fc, struct fs_parameter *param,
1158 bool is_vfat)
1159{
1160 struct fat_mount_options *opts = fc->fs_private;
1161 struct fs_parse_result result;
1162 int opt;
1163
1164 /* remount options have traditionally been ignored */
1165 if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE)
1166 return 0;
1167
1168 opt = fs_parse(fc, fat_param_spec, param, &result);
1169 /* If option not found in fat_param_spec, try vfat/msdos options */
1170 if (opt == -ENOPARAM) {
1171 if (is_vfat)
1172 opt = fs_parse(fc, vfat_param_spec, param, &result);
1173 else
1174 opt = fs_parse(fc, msdos_param_spec, param, &result);
1175 }
1176
1177 if (opt < 0)
1178 return opt;
1179
1180 switch (opt) {
1181 case Opt_check:
1182 opts->name_check = result.uint_32;
1183 break;
1184 case Opt_usefree:
1185 opts->usefree = 1;
1186 break;
1187 case Opt_nocase:
1188 if (!is_vfat)
1189 opts->nocase = 1;
1190 else {
1191 /* for backward compatibility */
1192 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1193 | VFAT_SFN_CREATE_WIN95;
1194 }
1195 break;
1196 case Opt_quiet:
1197 opts->quiet = 1;
1198 break;
1199 case Opt_showexec:
1200 opts->showexec = 1;
1201 break;
1202 case Opt_debug:
1203 opts->debug = 1;
1204 break;
1205 case Opt_immutable:
1206 opts->sys_immutable = 1;
1207 break;
1208 case Opt_uid:
1209 opts->fs_uid = result.uid;
1210 break;
1211 case Opt_gid:
1212 opts->fs_gid = result.gid;
1213 break;
1214 case Opt_umask:
1215 opts->fs_fmask = opts->fs_dmask = result.uint_32;
1216 break;
1217 case Opt_dmask:
1218 opts->fs_dmask = result.uint_32;
1219 break;
1220 case Opt_fmask:
1221 opts->fs_fmask = result.uint_32;
1222 break;
1223 case Opt_allow_utime:
1224 opts->allow_utime = result.uint_32 & (S_IWGRP | S_IWOTH);
1225 break;
1226 case Opt_codepage:
1227 opts->codepage = result.uint_32;
1228 break;
1229 case Opt_flush:
1230 opts->flush = 1;
1231 break;
1232 case Opt_time_offset:
1233 /*
1234 * GMT+-12 zones may have DST corrections so at least
1235 * 13 hours difference is needed. Make the limit 24
1236 * just in case someone invents something unusual.
1237 */
1238 if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
1239 return -EINVAL;
1240 opts->tz_set = 1;
1241 opts->time_offset = result.int_32;
1242 break;
1243 case Opt_tz:
1244 opts->tz_set = 1;
1245 opts->time_offset = result.uint_32;
1246 break;
1247 case Opt_errors:
1248 opts->errors = result.uint_32;
1249 break;
1250 case Opt_nfs:
1251 opts->nfs = FAT_NFS_STALE_RW;
1252 break;
1253 case Opt_nfs_enum:
1254 opts->nfs = result.uint_32;
1255 break;
1256 case Opt_dos1xfloppy:
1257 opts->dos1xfloppy = 1;
1258 break;
1259
1260 /* msdos specific */
1261 case Opt_dots: /* dots / nodots */
1262 opts->dotsOK = !result.negated;
1263 break;
1264 case Opt_dotsOK: /* dotsOK = yes/no */
1265 opts->dotsOK = result.boolean;
1266 break;
1267
1268 /* vfat specific */
1269 case Opt_charset:
1270 fat_reset_iocharset(opts);
1271 opts->iocharset = param->string;
1272 param->string = NULL; /* Steal string */
1273 break;
1274 case Opt_shortname:
1275 opts->shortname = result.uint_32;
1276 break;
1277 case Opt_utf8:
1278 opts->utf8 = 1;
1279 break;
1280 case Opt_utf8_bool:
1281 opts->utf8 = result.boolean;
1282 break;
1283 case Opt_uni_xl:
1284 opts->unicode_xlate = 1;
1285 break;
1286 case Opt_uni_xl_bool:
1287 opts->unicode_xlate = result.boolean;
1288 break;
1289 case Opt_nonumtail:
1290 opts->numtail = 0; /* negated option */
1291 break;
1292 case Opt_nonumtail_bool:
1293 opts->numtail = !result.boolean; /* negated option */
1294 break;
1295 case Opt_rodir:
1296 opts->rodir = 1;
1297 break;
1298 case Opt_discard:
1299 opts->discard = 1;
1300 break;
1301
1302 /* obsolete mount options */
1303 case Opt_obsolete:
1304 printk(KERN_INFO "FAT-fs: \"%s\" option is obsolete, "
1305 "not supported now", param->key);
1306 break;
1307 default:
1308 return -EINVAL;
1309 }
1310
1311 return 0;
1312}
1313EXPORT_SYMBOL_GPL(fat_parse_param);
1314
1315static int fat_read_root(struct inode *inode)
1316{
1317 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1318 int error;
1319
1320 MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1321 inode->i_uid = sbi->options.fs_uid;
1322 inode->i_gid = sbi->options.fs_gid;
1323 inode_inc_iversion(inode);
1324 inode->i_generation = 0;
1325 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1326 inode->i_op = sbi->dir_ops;
1327 inode->i_fop = &fat_dir_operations;
1328 if (is_fat32(sbi)) {
1329 MSDOS_I(inode)->i_start = sbi->root_cluster;
1330 error = fat_calc_dir_size(inode);
1331 if (error < 0)
1332 return error;
1333 } else {
1334 MSDOS_I(inode)->i_start = 0;
1335 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1336 }
1337 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1338 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1339 MSDOS_I(inode)->i_logstart = 0;
1340 MSDOS_I(inode)->mmu_private = inode->i_size;
1341
1342 fat_save_attrs(inode, ATTR_DIR);
1343 inode_set_mtime_to_ts(inode,
1344 inode_set_atime_to_ts(inode, inode_set_ctime(inode, 0, 0)));
1345 set_nlink(inode, fat_subdirs(inode)+2);
1346
1347 return 0;
1348}
1349
1350static unsigned long calc_fat_clusters(struct super_block *sb)
1351{
1352 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1353
1354 /* Divide first to avoid overflow */
1355 if (!is_fat12(sbi)) {
1356 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1357 return ent_per_sec * sbi->fat_length;
1358 }
1359
1360 return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1361}
1362
1363static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1364{
1365 if (get_unaligned_le16(&b->sector_size))
1366 return false;
1367 if (b->sec_per_clus)
1368 return false;
1369 if (b->reserved)
1370 return false;
1371 if (b->fats)
1372 return false;
1373 if (get_unaligned_le16(&b->dir_entries))
1374 return false;
1375 if (get_unaligned_le16(&b->sectors))
1376 return false;
1377 if (b->media)
1378 return false;
1379 if (b->fat_length)
1380 return false;
1381 if (b->secs_track)
1382 return false;
1383 if (b->heads)
1384 return false;
1385 return true;
1386}
1387
1388static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1389 int silent, struct fat_bios_param_block *bpb)
1390{
1391 int error = -EINVAL;
1392
1393 /* Read in BPB ... */
1394 memset(bpb, 0, sizeof(*bpb));
1395 bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1396 bpb->fat_sec_per_clus = b->sec_per_clus;
1397 bpb->fat_reserved = le16_to_cpu(b->reserved);
1398 bpb->fat_fats = b->fats;
1399 bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1400 bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1401 bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1402 bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1403
1404 bpb->fat16_state = b->fat16.state;
1405 bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1406
1407 bpb->fat32_length = le32_to_cpu(b->fat32.length);
1408 bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1409 bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1410 bpb->fat32_state = b->fat32.state;
1411 bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1412
1413 /* Validate this looks like a FAT filesystem BPB */
1414 if (!bpb->fat_reserved) {
1415 if (!silent)
1416 fat_msg(sb, KERN_ERR,
1417 "bogus number of reserved sectors");
1418 goto out;
1419 }
1420 if (!bpb->fat_fats) {
1421 if (!silent)
1422 fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1423 goto out;
1424 }
1425
1426 /*
1427 * Earlier we checked here that b->secs_track and b->head are nonzero,
1428 * but it turns out valid FAT filesystems can have zero there.
1429 */
1430
1431 if (!fat_valid_media(b->media)) {
1432 if (!silent)
1433 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1434 (unsigned)b->media);
1435 goto out;
1436 }
1437
1438 if (!is_power_of_2(bpb->fat_sector_size)
1439 || (bpb->fat_sector_size < 512)
1440 || (bpb->fat_sector_size > 4096)) {
1441 if (!silent)
1442 fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1443 (unsigned)bpb->fat_sector_size);
1444 goto out;
1445 }
1446
1447 if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1448 if (!silent)
1449 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1450 (unsigned)bpb->fat_sec_per_clus);
1451 goto out;
1452 }
1453
1454 if (bpb->fat_fat_length == 0 && bpb->fat32_length == 0) {
1455 if (!silent)
1456 fat_msg(sb, KERN_ERR, "bogus number of FAT sectors");
1457 goto out;
1458 }
1459
1460 error = 0;
1461
1462out:
1463 return error;
1464}
1465
1466static int fat_read_static_bpb(struct super_block *sb,
1467 struct fat_boot_sector *b, int silent,
1468 struct fat_bios_param_block *bpb)
1469{
1470 static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1471 sector_t bd_sects = bdev_nr_sectors(sb->s_bdev);
1472 struct fat_floppy_defaults *fdefaults = NULL;
1473 int error = -EINVAL;
1474 unsigned i;
1475
1476 /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1477 if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1478 if (!silent)
1479 fat_msg(sb, KERN_ERR,
1480 "%s; no bootstrapping code", notdos1x);
1481 goto out;
1482 }
1483
1484 /*
1485 * If any value in this region is non-zero, it isn't archaic
1486 * DOS.
1487 */
1488 if (!fat_bpb_is_zero(b)) {
1489 if (!silent)
1490 fat_msg(sb, KERN_ERR,
1491 "%s; DOS 2.x BPB is non-zero", notdos1x);
1492 goto out;
1493 }
1494
1495 for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1496 if (floppy_defaults[i].nr_sectors == bd_sects) {
1497 fdefaults = &floppy_defaults[i];
1498 break;
1499 }
1500 }
1501
1502 if (fdefaults == NULL) {
1503 if (!silent)
1504 fat_msg(sb, KERN_WARNING,
1505 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1506 (u64)bd_sects);
1507 goto out;
1508 }
1509
1510 if (!silent)
1511 fat_msg(sb, KERN_INFO,
1512 "This looks like a DOS 1.x volume; assuming default BPB values");
1513
1514 memset(bpb, 0, sizeof(*bpb));
1515 bpb->fat_sector_size = SECTOR_SIZE;
1516 bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1517 bpb->fat_reserved = 1;
1518 bpb->fat_fats = 2;
1519 bpb->fat_dir_entries = fdefaults->dir_entries;
1520 bpb->fat_sectors = fdefaults->nr_sectors;
1521 bpb->fat_fat_length = fdefaults->fat_length;
1522
1523 error = 0;
1524
1525out:
1526 return error;
1527}
1528
1529/*
1530 * Read the super block of an MS-DOS FS.
1531 */
1532int fat_fill_super(struct super_block *sb, struct fs_context *fc,
1533 void (*setup)(struct super_block *))
1534{
1535 struct fat_mount_options *opts = fc->fs_private;
1536 int silent = fc->sb_flags & SB_SILENT;
1537 struct inode *root_inode = NULL, *fat_inode = NULL;
1538 struct inode *fsinfo_inode = NULL;
1539 struct buffer_head *bh;
1540 struct fat_bios_param_block bpb;
1541 struct msdos_sb_info *sbi;
1542 u16 logical_sector_size;
1543 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1544 long error;
1545 char buf[50];
1546 struct timespec64 ts;
1547
1548 /*
1549 * GFP_KERNEL is ok here, because while we do hold the
1550 * superblock lock, memory pressure can't call back into
1551 * the filesystem, since we're only just about to mount
1552 * it and have no inodes etc active!
1553 */
1554 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1555 if (!sbi)
1556 return -ENOMEM;
1557 sb->s_fs_info = sbi;
1558
1559 sb->s_flags |= SB_NODIRATIME;
1560 sb->s_magic = MSDOS_SUPER_MAGIC;
1561 sb->s_op = &fat_sops;
1562 sb->s_export_op = &fat_export_ops;
1563 /*
1564 * fat timestamps are complex and truncated by fat itself, so
1565 * we set 1 here to be fast
1566 */
1567 sb->s_time_gran = 1;
1568 mutex_init(&sbi->nfs_build_inode_lock);
1569 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1570 DEFAULT_RATELIMIT_BURST);
1571
1572 /* UTF-8 doesn't provide FAT semantics */
1573 if (!strcmp(opts->iocharset, "utf8")) {
1574 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1575 " for FAT filesystems, filesystem will be"
1576 " case sensitive!");
1577 }
1578
1579 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1580 if (opts->allow_utime == (unsigned short)-1)
1581 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1582 if (opts->unicode_xlate)
1583 opts->utf8 = 0;
1584 if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1585 sb->s_flags |= SB_RDONLY;
1586 sb->s_export_op = &fat_export_ops_nostale;
1587 }
1588
1589 /* Apply parsed options to sbi (structure copy) */
1590 sbi->options = *opts;
1591 /* Transfer ownership of iocharset to sbi->options */
1592 opts->iocharset = NULL;
1593
1594 setup(sb); /* flavour-specific stuff that needs options */
1595
1596 error = -EIO;
1597 sb_min_blocksize(sb, 512);
1598 bh = sb_bread(sb, 0);
1599 if (bh == NULL) {
1600 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1601 goto out_fail;
1602 }
1603
1604 error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1605 &bpb);
1606 if (error == -EINVAL && sbi->options.dos1xfloppy)
1607 error = fat_read_static_bpb(sb,
1608 (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1609 brelse(bh);
1610
1611 if (error == -EINVAL)
1612 goto out_invalid;
1613 else if (error)
1614 goto out_fail;
1615
1616 logical_sector_size = bpb.fat_sector_size;
1617 sbi->sec_per_clus = bpb.fat_sec_per_clus;
1618
1619 error = -EIO;
1620 if (logical_sector_size < sb->s_blocksize) {
1621 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1622 " (logical sector size = %u)", logical_sector_size);
1623 goto out_fail;
1624 }
1625
1626 if (logical_sector_size > sb->s_blocksize) {
1627 struct buffer_head *bh_resize;
1628
1629 if (!sb_set_blocksize(sb, logical_sector_size)) {
1630 fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1631 logical_sector_size);
1632 goto out_fail;
1633 }
1634
1635 /* Verify that the larger boot sector is fully readable */
1636 bh_resize = sb_bread(sb, 0);
1637 if (bh_resize == NULL) {
1638 fat_msg(sb, KERN_ERR, "unable to read boot sector"
1639 " (logical sector size = %lu)",
1640 sb->s_blocksize);
1641 goto out_fail;
1642 }
1643 brelse(bh_resize);
1644 }
1645
1646 mutex_init(&sbi->s_lock);
1647 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1648 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1649 sbi->fats = bpb.fat_fats;
1650 sbi->fat_bits = 0; /* Don't know yet */
1651 sbi->fat_start = bpb.fat_reserved;
1652 sbi->fat_length = bpb.fat_fat_length;
1653 sbi->root_cluster = 0;
1654 sbi->free_clusters = -1; /* Don't know yet */
1655 sbi->free_clus_valid = 0;
1656 sbi->prev_free = FAT_START_ENT;
1657 sb->s_maxbytes = 0xffffffff;
1658 fat_time_fat2unix(sbi, &ts, 0, cpu_to_le16(FAT_DATE_MIN), 0);
1659 sb->s_time_min = ts.tv_sec;
1660
1661 fat_time_fat2unix(sbi, &ts, cpu_to_le16(FAT_TIME_MAX),
1662 cpu_to_le16(FAT_DATE_MAX), 0);
1663 sb->s_time_max = ts.tv_sec;
1664
1665 if (!sbi->fat_length && bpb.fat32_length) {
1666 struct fat_boot_fsinfo *fsinfo;
1667 struct buffer_head *fsinfo_bh;
1668
1669 /* Must be FAT32 */
1670 sbi->fat_bits = 32;
1671 sbi->fat_length = bpb.fat32_length;
1672 sbi->root_cluster = bpb.fat32_root_cluster;
1673
1674 /* MC - if info_sector is 0, don't multiply by 0 */
1675 sbi->fsinfo_sector = bpb.fat32_info_sector;
1676 if (sbi->fsinfo_sector == 0)
1677 sbi->fsinfo_sector = 1;
1678
1679 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1680 if (fsinfo_bh == NULL) {
1681 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1682 " (sector = %lu)", sbi->fsinfo_sector);
1683 goto out_fail;
1684 }
1685
1686 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1687 if (!IS_FSINFO(fsinfo)) {
1688 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1689 "0x%08x, 0x%08x (sector = %lu)",
1690 le32_to_cpu(fsinfo->signature1),
1691 le32_to_cpu(fsinfo->signature2),
1692 sbi->fsinfo_sector);
1693 } else {
1694 if (sbi->options.usefree)
1695 sbi->free_clus_valid = 1;
1696 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1697 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1698 }
1699
1700 brelse(fsinfo_bh);
1701 }
1702
1703 /* interpret volume ID as a little endian 32 bit integer */
1704 if (is_fat32(sbi))
1705 sbi->vol_id = bpb.fat32_vol_id;
1706 else /* fat 16 or 12 */
1707 sbi->vol_id = bpb.fat16_vol_id;
1708
1709 __le32 vol_id_le = cpu_to_le32(sbi->vol_id);
1710 super_set_uuid(sb, (void *) &vol_id_le, sizeof(vol_id_le));
1711
1712 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1713 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1714
1715 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1716 sbi->dir_entries = bpb.fat_dir_entries;
1717 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1718 if (!silent)
1719 fat_msg(sb, KERN_ERR, "bogus number of directory entries"
1720 " (%u)", sbi->dir_entries);
1721 goto out_invalid;
1722 }
1723
1724 rootdir_sectors = sbi->dir_entries
1725 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1726 sbi->data_start = sbi->dir_start + rootdir_sectors;
1727 total_sectors = bpb.fat_sectors;
1728 if (total_sectors == 0)
1729 total_sectors = bpb.fat_total_sect;
1730
1731 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1732
1733 if (!is_fat32(sbi))
1734 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1735
1736 /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1737 if (is_fat32(sbi))
1738 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1739 else /* fat 16 or 12 */
1740 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1741
1742 /* check that FAT table does not overflow */
1743 fat_clusters = calc_fat_clusters(sb);
1744 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1745 if (total_clusters > max_fat(sb)) {
1746 if (!silent)
1747 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1748 total_clusters);
1749 goto out_invalid;
1750 }
1751
1752 sbi->max_cluster = total_clusters + FAT_START_ENT;
1753 /* check the free_clusters, it's not necessarily correct */
1754 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1755 sbi->free_clusters = -1;
1756 /* check the prev_free, it's not necessarily correct */
1757 sbi->prev_free %= sbi->max_cluster;
1758 if (sbi->prev_free < FAT_START_ENT)
1759 sbi->prev_free = FAT_START_ENT;
1760
1761 /* set up enough so that it can read an inode */
1762 fat_hash_init(sb);
1763 dir_hash_init(sb);
1764 fat_ent_access_init(sb);
1765
1766 /*
1767 * The low byte of the first FAT entry must have the same value as
1768 * the media field of the boot sector. But in real world, too many
1769 * devices are writing wrong values. So, removed that validity check.
1770 *
1771 * The removed check compared the first FAT entry to a value dependent
1772 * on the media field like this:
1773 * == (0x0F00 | media), for FAT12
1774 * == (0XFF00 | media), for FAT16
1775 * == (0x0FFFFF | media), for FAT32
1776 */
1777
1778 error = -EINVAL;
1779 sprintf(buf, "cp%d", sbi->options.codepage);
1780 sbi->nls_disk = load_nls(buf);
1781 if (!sbi->nls_disk) {
1782 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1783 goto out_fail;
1784 }
1785
1786 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1787 if (sbi->options.isvfat) {
1788 sbi->nls_io = load_nls(sbi->options.iocharset);
1789 if (!sbi->nls_io) {
1790 fat_msg(sb, KERN_ERR, "IO charset %s not found",
1791 sbi->options.iocharset);
1792 goto out_fail;
1793 }
1794 }
1795
1796 error = -ENOMEM;
1797 fat_inode = new_inode(sb);
1798 if (!fat_inode)
1799 goto out_fail;
1800 sbi->fat_inode = fat_inode;
1801
1802 fsinfo_inode = new_inode(sb);
1803 if (!fsinfo_inode)
1804 goto out_fail;
1805 fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1806 sbi->fsinfo_inode = fsinfo_inode;
1807 insert_inode_hash(fsinfo_inode);
1808
1809 root_inode = new_inode(sb);
1810 if (!root_inode)
1811 goto out_fail;
1812 root_inode->i_ino = MSDOS_ROOT_INO;
1813 inode_set_iversion(root_inode, 1);
1814 error = fat_read_root(root_inode);
1815 if (error < 0) {
1816 iput(root_inode);
1817 goto out_fail;
1818 }
1819 error = -ENOMEM;
1820 insert_inode_hash(root_inode);
1821 fat_attach(root_inode, 0);
1822 sb->s_root = d_make_root(root_inode);
1823 if (!sb->s_root) {
1824 fat_msg(sb, KERN_ERR, "get root inode failed");
1825 goto out_fail;
1826 }
1827
1828 if (sbi->options.discard && !bdev_max_discard_sectors(sb->s_bdev))
1829 fat_msg(sb, KERN_WARNING,
1830 "mounting with \"discard\" option, but the device does not support discard");
1831
1832 fat_set_state(sb, 1, 0);
1833 return 0;
1834
1835out_invalid:
1836 error = -EINVAL;
1837 if (!silent)
1838 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1839
1840out_fail:
1841 iput(fsinfo_inode);
1842 iput(fat_inode);
1843 unload_nls(sbi->nls_io);
1844 unload_nls(sbi->nls_disk);
1845 fat_reset_iocharset(&sbi->options);
1846 sb->s_fs_info = NULL;
1847 kfree(sbi);
1848 return error;
1849}
1850
1851EXPORT_SYMBOL_GPL(fat_fill_super);
1852
1853/*
1854 * helper function for fat_flush_inodes. This writes both the inode
1855 * and the file data blocks, waiting for in flight data blocks before
1856 * the start of the call. It does not wait for any io started
1857 * during the call
1858 */
1859static int writeback_inode(struct inode *inode)
1860{
1861
1862 int ret;
1863
1864 /* if we used wait=1, sync_inode_metadata waits for the io for the
1865 * inode to finish. So wait=0 is sent down to sync_inode_metadata
1866 * and filemap_fdatawrite is used for the data blocks
1867 */
1868 ret = sync_inode_metadata(inode, 0);
1869 if (!ret)
1870 ret = filemap_fdatawrite(inode->i_mapping);
1871 return ret;
1872}
1873
1874/*
1875 * write data and metadata corresponding to i1 and i2. The io is
1876 * started but we do not wait for any of it to finish.
1877 *
1878 * filemap_flush is used for the block device, so if there is a dirty
1879 * page for a block already in flight, we will not wait and start the
1880 * io over again
1881 */
1882int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1883{
1884 int ret = 0;
1885 if (!MSDOS_SB(sb)->options.flush)
1886 return 0;
1887 if (i1)
1888 ret = writeback_inode(i1);
1889 if (!ret && i2)
1890 ret = writeback_inode(i2);
1891 if (!ret)
1892 ret = sync_blockdev_nowait(sb->s_bdev);
1893 return ret;
1894}
1895EXPORT_SYMBOL_GPL(fat_flush_inodes);
1896
1897int fat_init_fs_context(struct fs_context *fc, bool is_vfat)
1898{
1899 struct fat_mount_options *opts;
1900
1901 opts = kzalloc(sizeof(*opts), GFP_KERNEL);
1902 if (!opts)
1903 return -ENOMEM;
1904
1905 opts->isvfat = is_vfat;
1906 opts->fs_uid = current_uid();
1907 opts->fs_gid = current_gid();
1908 opts->fs_fmask = opts->fs_dmask = current_umask();
1909 opts->allow_utime = -1;
1910 opts->codepage = fat_default_codepage;
1911 fat_reset_iocharset(opts);
1912 if (is_vfat) {
1913 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1914 opts->rodir = 0;
1915 } else {
1916 opts->shortname = 0;
1917 opts->rodir = 1;
1918 }
1919 opts->name_check = 'n';
1920 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
1921 opts->unicode_xlate = 0;
1922 opts->numtail = 1;
1923 opts->usefree = opts->nocase = 0;
1924 opts->tz_set = 0;
1925 opts->nfs = 0;
1926 opts->errors = FAT_ERRORS_RO;
1927 opts->debug = 0;
1928
1929 opts->utf8 = IS_ENABLED(CONFIG_FAT_DEFAULT_UTF8) && is_vfat;
1930
1931 fc->fs_private = opts;
1932 /* fc->ops assigned by caller */
1933
1934 return 0;
1935}
1936EXPORT_SYMBOL_GPL(fat_init_fs_context);
1937
1938void fat_free_fc(struct fs_context *fc)
1939{
1940 struct fat_mount_options *opts = fc->fs_private;
1941
1942 if (opts->iocharset != fat_default_iocharset)
1943 kfree(opts->iocharset);
1944 kfree(fc->fs_private);
1945}
1946EXPORT_SYMBOL_GPL(fat_free_fc);
1947
1948static 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
1962failed:
1963 fat_cache_destroy();
1964 return err;
1965}
1966
1967static void __exit exit_fat_fs(void)
1968{
1969 fat_cache_destroy();
1970 fat_destroy_inodecache();
1971}
1972
1973module_init(init_fat_fs)
1974module_exit(exit_fat_fs)
1975
1976MODULE_DESCRIPTION("Core FAT filesystem support");
1977MODULE_LICENSE("GPL");