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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/parser.h>
20#include <linux/uio.h>
21#include <linux/blkdev.h>
22#include <linux/backing-dev.h>
23#include <asm/unaligned.h>
24#include <linux/random.h>
25#include <linux/iversion.h>
26#include "fat.h"
27
28#ifndef CONFIG_FAT_DEFAULT_IOCHARSET
29/* if user don't select VFAT, this is undefined. */
30#define CONFIG_FAT_DEFAULT_IOCHARSET ""
31#endif
32
33#define KB_IN_SECTORS 2
34
35/* DOS dates from 1980/1/1 through 2107/12/31 */
36#define FAT_DATE_MIN (0<<9 | 1<<5 | 1)
37#define FAT_DATE_MAX (127<<9 | 12<<5 | 31)
38#define FAT_TIME_MAX (23<<11 | 59<<5 | 29)
39
40/*
41 * A deserialized copy of the on-disk structure laid out in struct
42 * fat_boot_sector.
43 */
44struct fat_bios_param_block {
45 u16 fat_sector_size;
46 u8 fat_sec_per_clus;
47 u16 fat_reserved;
48 u8 fat_fats;
49 u16 fat_dir_entries;
50 u16 fat_sectors;
51 u16 fat_fat_length;
52 u32 fat_total_sect;
53
54 u8 fat16_state;
55 u32 fat16_vol_id;
56
57 u32 fat32_length;
58 u32 fat32_root_cluster;
59 u16 fat32_info_sector;
60 u8 fat32_state;
61 u32 fat32_vol_id;
62};
63
64static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
65static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
66
67static struct fat_floppy_defaults {
68 unsigned nr_sectors;
69 unsigned sec_per_clus;
70 unsigned dir_entries;
71 unsigned media;
72 unsigned fat_length;
73} floppy_defaults[] = {
74{
75 .nr_sectors = 160 * KB_IN_SECTORS,
76 .sec_per_clus = 1,
77 .dir_entries = 64,
78 .media = 0xFE,
79 .fat_length = 1,
80},
81{
82 .nr_sectors = 180 * KB_IN_SECTORS,
83 .sec_per_clus = 1,
84 .dir_entries = 64,
85 .media = 0xFC,
86 .fat_length = 2,
87},
88{
89 .nr_sectors = 320 * KB_IN_SECTORS,
90 .sec_per_clus = 2,
91 .dir_entries = 112,
92 .media = 0xFF,
93 .fat_length = 1,
94},
95{
96 .nr_sectors = 360 * KB_IN_SECTORS,
97 .sec_per_clus = 2,
98 .dir_entries = 112,
99 .media = 0xFD,
100 .fat_length = 2,
101},
102};
103
104int fat_add_cluster(struct inode *inode)
105{
106 int err, cluster;
107
108 err = fat_alloc_clusters(inode, &cluster, 1);
109 if (err)
110 return err;
111 /* FIXME: this cluster should be added after data of this
112 * cluster is writed */
113 err = fat_chain_add(inode, cluster, 1);
114 if (err)
115 fat_free_clusters(inode, cluster);
116 return err;
117}
118
119static inline int __fat_get_block(struct inode *inode, sector_t iblock,
120 unsigned long *max_blocks,
121 struct buffer_head *bh_result, int create)
122{
123 struct super_block *sb = inode->i_sb;
124 struct msdos_sb_info *sbi = MSDOS_SB(sb);
125 unsigned long mapped_blocks;
126 sector_t phys, last_block;
127 int err, offset;
128
129 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
130 if (err)
131 return err;
132 if (phys) {
133 map_bh(bh_result, sb, phys);
134 *max_blocks = min(mapped_blocks, *max_blocks);
135 return 0;
136 }
137 if (!create)
138 return 0;
139
140 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
141 fat_fs_error(sb, "corrupted file size (i_pos %lld, %lld)",
142 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
143 return -EIO;
144 }
145
146 last_block = inode->i_blocks >> (sb->s_blocksize_bits - 9);
147 offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
148 /*
149 * allocate a cluster according to the following.
150 * 1) no more available blocks
151 * 2) not part of fallocate region
152 */
153 if (!offset && !(iblock < last_block)) {
154 /* TODO: multiple cluster allocation would be desirable. */
155 err = fat_add_cluster(inode);
156 if (err)
157 return err;
158 }
159 /* available blocks on this cluster */
160 mapped_blocks = sbi->sec_per_clus - offset;
161
162 *max_blocks = min(mapped_blocks, *max_blocks);
163 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
164
165 err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
166 if (err)
167 return err;
168 if (!phys) {
169 fat_fs_error(sb,
170 "invalid FAT chain (i_pos %lld, last_block %llu)",
171 MSDOS_I(inode)->i_pos,
172 (unsigned long long)last_block);
173 return -EIO;
174 }
175
176 BUG_ON(*max_blocks != mapped_blocks);
177 set_buffer_new(bh_result);
178 map_bh(bh_result, sb, phys);
179
180 return 0;
181}
182
183static int fat_get_block(struct inode *inode, sector_t iblock,
184 struct buffer_head *bh_result, int create)
185{
186 struct super_block *sb = inode->i_sb;
187 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
188 int err;
189
190 err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
191 if (err)
192 return err;
193 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
194 return 0;
195}
196
197static int fat_writepages(struct address_space *mapping,
198 struct writeback_control *wbc)
199{
200 return mpage_writepages(mapping, wbc, fat_get_block);
201}
202
203static int fat_read_folio(struct file *file, struct folio *folio)
204{
205 return mpage_read_folio(folio, fat_get_block);
206}
207
208static void fat_readahead(struct readahead_control *rac)
209{
210 mpage_readahead(rac, fat_get_block);
211}
212
213static void fat_write_failed(struct address_space *mapping, loff_t to)
214{
215 struct inode *inode = mapping->host;
216
217 if (to > inode->i_size) {
218 truncate_pagecache(inode, inode->i_size);
219 fat_truncate_blocks(inode, inode->i_size);
220 }
221}
222
223static int fat_write_begin(struct file *file, struct address_space *mapping,
224 loff_t pos, unsigned len,
225 struct page **pagep, void **fsdata)
226{
227 int err;
228
229 *pagep = NULL;
230 err = cont_write_begin(file, mapping, pos, len,
231 pagep, fsdata, fat_get_block,
232 &MSDOS_I(mapping->host)->mmu_private);
233 if (err < 0)
234 fat_write_failed(mapping, pos + len);
235 return err;
236}
237
238static int fat_write_end(struct file *file, struct address_space *mapping,
239 loff_t pos, unsigned len, unsigned copied,
240 struct page *pagep, void *fsdata)
241{
242 struct inode *inode = mapping->host;
243 int err;
244 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
245 if (err < len)
246 fat_write_failed(mapping, pos + len);
247 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
248 fat_truncate_time(inode, NULL, S_CTIME|S_MTIME);
249 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
250 mark_inode_dirty(inode);
251 }
252 return err;
253}
254
255static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
256{
257 struct file *file = iocb->ki_filp;
258 struct address_space *mapping = file->f_mapping;
259 struct inode *inode = mapping->host;
260 size_t count = iov_iter_count(iter);
261 loff_t offset = iocb->ki_pos;
262 ssize_t ret;
263
264 if (iov_iter_rw(iter) == WRITE) {
265 /*
266 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
267 * so we need to update the ->mmu_private to block boundary.
268 *
269 * But we must fill the remaining area or hole by nul for
270 * updating ->mmu_private.
271 *
272 * Return 0, and fallback to normal buffered write.
273 */
274 loff_t size = offset + count;
275 if (MSDOS_I(inode)->mmu_private < size)
276 return 0;
277 }
278
279 /*
280 * FAT need to use the DIO_LOCKING for avoiding the race
281 * condition of fat_get_block() and ->truncate().
282 */
283 ret = blockdev_direct_IO(iocb, inode, iter, fat_get_block);
284 if (ret < 0 && iov_iter_rw(iter) == WRITE)
285 fat_write_failed(mapping, offset + count);
286
287 return ret;
288}
289
290static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
291 struct buffer_head *bh_result, int create)
292{
293 struct super_block *sb = inode->i_sb;
294 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
295 int err;
296 sector_t bmap;
297 unsigned long mapped_blocks;
298
299 BUG_ON(create != 0);
300
301 err = fat_bmap(inode, iblock, &bmap, &mapped_blocks, create, true);
302 if (err)
303 return err;
304
305 if (bmap) {
306 map_bh(bh_result, sb, bmap);
307 max_blocks = min(mapped_blocks, max_blocks);
308 }
309
310 bh_result->b_size = max_blocks << sb->s_blocksize_bits;
311
312 return 0;
313}
314
315static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
316{
317 sector_t blocknr;
318
319 /* fat_get_cluster() assumes the requested blocknr isn't truncated. */
320 down_read(&MSDOS_I(mapping->host)->truncate_lock);
321 blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
322 up_read(&MSDOS_I(mapping->host)->truncate_lock);
323
324 return blocknr;
325}
326
327/*
328 * fat_block_truncate_page() zeroes out a mapping from file offset `from'
329 * up to the end of the block which corresponds to `from'.
330 * This is required during truncate to physically zeroout the tail end
331 * of that block so it doesn't yield old data if the file is later grown.
332 * Also, avoid causing failure from fsx for cases of "data past EOF"
333 */
334int fat_block_truncate_page(struct inode *inode, loff_t from)
335{
336 return block_truncate_page(inode->i_mapping, from, fat_get_block);
337}
338
339static const struct address_space_operations fat_aops = {
340 .dirty_folio = block_dirty_folio,
341 .invalidate_folio = block_invalidate_folio,
342 .read_folio = fat_read_folio,
343 .readahead = fat_readahead,
344 .writepages = fat_writepages,
345 .write_begin = fat_write_begin,
346 .write_end = fat_write_end,
347 .direct_IO = fat_direct_IO,
348 .bmap = _fat_bmap,
349 .migrate_folio = buffer_migrate_folio,
350};
351
352/*
353 * New FAT inode stuff. We do the following:
354 * a) i_ino is constant and has nothing with on-disk location.
355 * b) FAT manages its own cache of directory entries.
356 * c) *This* cache is indexed by on-disk location.
357 * d) inode has an associated directory entry, all right, but
358 * it may be unhashed.
359 * e) currently entries are stored within struct inode. That should
360 * change.
361 * f) we deal with races in the following way:
362 * 1. readdir() and lookup() do FAT-dir-cache lookup.
363 * 2. rename() unhashes the F-d-c entry and rehashes it in
364 * a new place.
365 * 3. unlink() and rmdir() unhash F-d-c entry.
366 * 4. fat_write_inode() checks whether the thing is unhashed.
367 * If it is we silently return. If it isn't we do bread(),
368 * check if the location is still valid and retry if it
369 * isn't. Otherwise we do changes.
370 * 5. Spinlock is used to protect hash/unhash/location check/lookup
371 * 6. fat_evict_inode() unhashes the F-d-c entry.
372 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
373 * and consider negative result as cache miss.
374 */
375
376static void fat_hash_init(struct super_block *sb)
377{
378 struct msdos_sb_info *sbi = MSDOS_SB(sb);
379 int i;
380
381 spin_lock_init(&sbi->inode_hash_lock);
382 for (i = 0; i < FAT_HASH_SIZE; i++)
383 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
384}
385
386static inline unsigned long fat_hash(loff_t i_pos)
387{
388 return hash_32(i_pos, FAT_HASH_BITS);
389}
390
391static void dir_hash_init(struct super_block *sb)
392{
393 struct msdos_sb_info *sbi = MSDOS_SB(sb);
394 int i;
395
396 spin_lock_init(&sbi->dir_hash_lock);
397 for (i = 0; i < FAT_HASH_SIZE; i++)
398 INIT_HLIST_HEAD(&sbi->dir_hashtable[i]);
399}
400
401void fat_attach(struct inode *inode, loff_t i_pos)
402{
403 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
404
405 if (inode->i_ino != MSDOS_ROOT_INO) {
406 struct hlist_head *head = sbi->inode_hashtable
407 + fat_hash(i_pos);
408
409 spin_lock(&sbi->inode_hash_lock);
410 MSDOS_I(inode)->i_pos = i_pos;
411 hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
412 spin_unlock(&sbi->inode_hash_lock);
413 }
414
415 /* If NFS support is enabled, cache the mapping of start cluster
416 * to directory inode. This is used during reconnection of
417 * dentries to the filesystem root.
418 */
419 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
420 struct hlist_head *d_head = sbi->dir_hashtable;
421 d_head += fat_dir_hash(MSDOS_I(inode)->i_logstart);
422
423 spin_lock(&sbi->dir_hash_lock);
424 hlist_add_head(&MSDOS_I(inode)->i_dir_hash, d_head);
425 spin_unlock(&sbi->dir_hash_lock);
426 }
427}
428EXPORT_SYMBOL_GPL(fat_attach);
429
430void fat_detach(struct inode *inode)
431{
432 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
433 spin_lock(&sbi->inode_hash_lock);
434 MSDOS_I(inode)->i_pos = 0;
435 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
436 spin_unlock(&sbi->inode_hash_lock);
437
438 if (S_ISDIR(inode->i_mode) && sbi->options.nfs) {
439 spin_lock(&sbi->dir_hash_lock);
440 hlist_del_init(&MSDOS_I(inode)->i_dir_hash);
441 spin_unlock(&sbi->dir_hash_lock);
442 }
443}
444EXPORT_SYMBOL_GPL(fat_detach);
445
446struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
447{
448 struct msdos_sb_info *sbi = MSDOS_SB(sb);
449 struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
450 struct msdos_inode_info *i;
451 struct inode *inode = NULL;
452
453 spin_lock(&sbi->inode_hash_lock);
454 hlist_for_each_entry(i, head, i_fat_hash) {
455 BUG_ON(i->vfs_inode.i_sb != sb);
456 if (i->i_pos != i_pos)
457 continue;
458 inode = igrab(&i->vfs_inode);
459 if (inode)
460 break;
461 }
462 spin_unlock(&sbi->inode_hash_lock);
463 return inode;
464}
465
466static int is_exec(unsigned char *extension)
467{
468 unsigned char exe_extensions[] = "EXECOMBAT", *walk;
469
470 for (walk = exe_extensions; *walk; walk += 3)
471 if (!strncmp(extension, walk, 3))
472 return 1;
473 return 0;
474}
475
476static int fat_calc_dir_size(struct inode *inode)
477{
478 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
479 int ret, fclus, dclus;
480
481 inode->i_size = 0;
482 if (MSDOS_I(inode)->i_start == 0)
483 return 0;
484
485 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
486 if (ret < 0)
487 return ret;
488 inode->i_size = (fclus + 1) << sbi->cluster_bits;
489
490 return 0;
491}
492
493static int fat_validate_dir(struct inode *dir)
494{
495 struct super_block *sb = dir->i_sb;
496
497 if (dir->i_nlink < 2) {
498 /* Directory should have "."/".." entries at least. */
499 fat_fs_error(sb, "corrupted directory (invalid entries)");
500 return -EIO;
501 }
502 if (MSDOS_I(dir)->i_start == 0 ||
503 MSDOS_I(dir)->i_start == MSDOS_SB(sb)->root_cluster) {
504 /* Directory should point valid cluster. */
505 fat_fs_error(sb, "corrupted directory (invalid i_start)");
506 return -EIO;
507 }
508 return 0;
509}
510
511/* doesn't deal with root inode */
512int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
513{
514 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
515 int error;
516
517 MSDOS_I(inode)->i_pos = 0;
518 inode->i_uid = sbi->options.fs_uid;
519 inode->i_gid = sbi->options.fs_gid;
520 inode_inc_iversion(inode);
521 inode->i_generation = get_random_u32();
522
523 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
524 inode->i_generation &= ~1;
525 inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
526 inode->i_op = sbi->dir_ops;
527 inode->i_fop = &fat_dir_operations;
528
529 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
530 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
531 error = fat_calc_dir_size(inode);
532 if (error < 0)
533 return error;
534 MSDOS_I(inode)->mmu_private = inode->i_size;
535
536 set_nlink(inode, fat_subdirs(inode));
537
538 error = fat_validate_dir(inode);
539 if (error < 0)
540 return error;
541 } else { /* not a directory */
542 inode->i_generation |= 1;
543 inode->i_mode = fat_make_mode(sbi, de->attr,
544 ((sbi->options.showexec && !is_exec(de->name + 8))
545 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
546 MSDOS_I(inode)->i_start = fat_get_start(sbi, de);
547
548 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
549 inode->i_size = le32_to_cpu(de->size);
550 inode->i_op = &fat_file_inode_operations;
551 inode->i_fop = &fat_file_operations;
552 inode->i_mapping->a_ops = &fat_aops;
553 MSDOS_I(inode)->mmu_private = inode->i_size;
554 }
555 if (de->attr & ATTR_SYS) {
556 if (sbi->options.sys_immutable)
557 inode->i_flags |= S_IMMUTABLE;
558 }
559 fat_save_attrs(inode, de->attr);
560
561 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
562 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
563
564 fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
565 inode->i_ctime = inode->i_mtime;
566 if (sbi->options.isvfat) {
567 fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
568 fat_time_fat2unix(sbi, &MSDOS_I(inode)->i_crtime, de->ctime,
569 de->cdate, de->ctime_cs);
570 } else
571 inode->i_atime = fat_truncate_atime(sbi, &inode->i_mtime);
572
573 return 0;
574}
575
576static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
577{
578 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
579 mutex_lock(&sbi->nfs_build_inode_lock);
580}
581
582static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
583{
584 if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
585 mutex_unlock(&sbi->nfs_build_inode_lock);
586}
587
588struct inode *fat_build_inode(struct super_block *sb,
589 struct msdos_dir_entry *de, loff_t i_pos)
590{
591 struct inode *inode;
592 int err;
593
594 fat_lock_build_inode(MSDOS_SB(sb));
595 inode = fat_iget(sb, i_pos);
596 if (inode)
597 goto out;
598 inode = new_inode(sb);
599 if (!inode) {
600 inode = ERR_PTR(-ENOMEM);
601 goto out;
602 }
603 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
604 inode_set_iversion(inode, 1);
605 err = fat_fill_inode(inode, de);
606 if (err) {
607 iput(inode);
608 inode = ERR_PTR(err);
609 goto out;
610 }
611 fat_attach(inode, i_pos);
612 insert_inode_hash(inode);
613out:
614 fat_unlock_build_inode(MSDOS_SB(sb));
615 return inode;
616}
617
618EXPORT_SYMBOL_GPL(fat_build_inode);
619
620static int __fat_write_inode(struct inode *inode, int wait);
621
622static void fat_free_eofblocks(struct inode *inode)
623{
624 /* Release unwritten fallocated blocks on inode eviction. */
625 if ((inode->i_blocks << 9) >
626 round_up(MSDOS_I(inode)->mmu_private,
627 MSDOS_SB(inode->i_sb)->cluster_size)) {
628 int err;
629
630 fat_truncate_blocks(inode, MSDOS_I(inode)->mmu_private);
631 /* Fallocate results in updating the i_start/iogstart
632 * for the zero byte file. So, make it return to
633 * original state during evict and commit it to avoid
634 * any corruption on the next access to the cluster
635 * chain for the file.
636 */
637 err = __fat_write_inode(inode, inode_needs_sync(inode));
638 if (err) {
639 fat_msg(inode->i_sb, KERN_WARNING, "Failed to "
640 "update on disk inode for unused "
641 "fallocated blocks, inode could be "
642 "corrupted. Please run fsck");
643 }
644
645 }
646}
647
648static void fat_evict_inode(struct inode *inode)
649{
650 truncate_inode_pages_final(&inode->i_data);
651 if (!inode->i_nlink) {
652 inode->i_size = 0;
653 fat_truncate_blocks(inode, 0);
654 } else
655 fat_free_eofblocks(inode);
656
657 invalidate_inode_buffers(inode);
658 clear_inode(inode);
659 fat_cache_inval_inode(inode);
660 fat_detach(inode);
661}
662
663static void fat_set_state(struct super_block *sb,
664 unsigned int set, unsigned int force)
665{
666 struct buffer_head *bh;
667 struct fat_boot_sector *b;
668 struct msdos_sb_info *sbi = MSDOS_SB(sb);
669
670 /* do not change any thing if mounted read only */
671 if (sb_rdonly(sb) && !force)
672 return;
673
674 /* do not change state if fs was dirty */
675 if (sbi->dirty) {
676 /* warn only on set (mount). */
677 if (set)
678 fat_msg(sb, KERN_WARNING, "Volume was not properly "
679 "unmounted. Some data may be corrupt. "
680 "Please run fsck.");
681 return;
682 }
683
684 bh = sb_bread(sb, 0);
685 if (bh == NULL) {
686 fat_msg(sb, KERN_ERR, "unable to read boot sector "
687 "to mark fs as dirty");
688 return;
689 }
690
691 b = (struct fat_boot_sector *) bh->b_data;
692
693 if (is_fat32(sbi)) {
694 if (set)
695 b->fat32.state |= FAT_STATE_DIRTY;
696 else
697 b->fat32.state &= ~FAT_STATE_DIRTY;
698 } else /* fat 16 and 12 */ {
699 if (set)
700 b->fat16.state |= FAT_STATE_DIRTY;
701 else
702 b->fat16.state &= ~FAT_STATE_DIRTY;
703 }
704
705 mark_buffer_dirty(bh);
706 sync_dirty_buffer(bh);
707 brelse(bh);
708}
709
710static void fat_reset_iocharset(struct fat_mount_options *opts)
711{
712 if (opts->iocharset != fat_default_iocharset) {
713 /* Note: opts->iocharset can be NULL here */
714 kfree(opts->iocharset);
715 opts->iocharset = fat_default_iocharset;
716 }
717}
718
719static void delayed_free(struct rcu_head *p)
720{
721 struct msdos_sb_info *sbi = container_of(p, struct msdos_sb_info, rcu);
722 unload_nls(sbi->nls_disk);
723 unload_nls(sbi->nls_io);
724 fat_reset_iocharset(&sbi->options);
725 kfree(sbi);
726}
727
728static void fat_put_super(struct super_block *sb)
729{
730 struct msdos_sb_info *sbi = MSDOS_SB(sb);
731
732 fat_set_state(sb, 0, 0);
733
734 iput(sbi->fsinfo_inode);
735 iput(sbi->fat_inode);
736
737 call_rcu(&sbi->rcu, delayed_free);
738}
739
740static struct kmem_cache *fat_inode_cachep;
741
742static struct inode *fat_alloc_inode(struct super_block *sb)
743{
744 struct msdos_inode_info *ei;
745 ei = alloc_inode_sb(sb, fat_inode_cachep, GFP_NOFS);
746 if (!ei)
747 return NULL;
748
749 init_rwsem(&ei->truncate_lock);
750 /* Zeroing to allow iput() even if partial initialized inode. */
751 ei->mmu_private = 0;
752 ei->i_start = 0;
753 ei->i_logstart = 0;
754 ei->i_attrs = 0;
755 ei->i_pos = 0;
756 ei->i_crtime.tv_sec = 0;
757 ei->i_crtime.tv_nsec = 0;
758
759 return &ei->vfs_inode;
760}
761
762static void fat_free_inode(struct inode *inode)
763{
764 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
765}
766
767static void init_once(void *foo)
768{
769 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
770
771 spin_lock_init(&ei->cache_lru_lock);
772 ei->nr_caches = 0;
773 ei->cache_valid_id = FAT_CACHE_VALID + 1;
774 INIT_LIST_HEAD(&ei->cache_lru);
775 INIT_HLIST_NODE(&ei->i_fat_hash);
776 INIT_HLIST_NODE(&ei->i_dir_hash);
777 inode_init_once(&ei->vfs_inode);
778}
779
780static int __init fat_init_inodecache(void)
781{
782 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
783 sizeof(struct msdos_inode_info),
784 0, (SLAB_RECLAIM_ACCOUNT|
785 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
786 init_once);
787 if (fat_inode_cachep == NULL)
788 return -ENOMEM;
789 return 0;
790}
791
792static void __exit fat_destroy_inodecache(void)
793{
794 /*
795 * Make sure all delayed rcu free inodes are flushed before we
796 * destroy cache.
797 */
798 rcu_barrier();
799 kmem_cache_destroy(fat_inode_cachep);
800}
801
802static int fat_remount(struct super_block *sb, int *flags, char *data)
803{
804 bool new_rdonly;
805 struct msdos_sb_info *sbi = MSDOS_SB(sb);
806 *flags |= SB_NODIRATIME | (sbi->options.isvfat ? 0 : SB_NOATIME);
807
808 sync_filesystem(sb);
809
810 /* make sure we update state on remount. */
811 new_rdonly = *flags & SB_RDONLY;
812 if (new_rdonly != sb_rdonly(sb)) {
813 if (new_rdonly)
814 fat_set_state(sb, 0, 0);
815 else
816 fat_set_state(sb, 1, 1);
817 }
818 return 0;
819}
820
821static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
822{
823 struct super_block *sb = dentry->d_sb;
824 struct msdos_sb_info *sbi = MSDOS_SB(sb);
825 u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
826
827 /* If the count of free cluster is still unknown, counts it here. */
828 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
829 int err = fat_count_free_clusters(dentry->d_sb);
830 if (err)
831 return err;
832 }
833
834 buf->f_type = dentry->d_sb->s_magic;
835 buf->f_bsize = sbi->cluster_size;
836 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
837 buf->f_bfree = sbi->free_clusters;
838 buf->f_bavail = sbi->free_clusters;
839 buf->f_fsid = u64_to_fsid(id);
840 buf->f_namelen =
841 (sbi->options.isvfat ? FAT_LFN_LEN : 12) * NLS_MAX_CHARSET_SIZE;
842
843 return 0;
844}
845
846static int __fat_write_inode(struct inode *inode, int wait)
847{
848 struct super_block *sb = inode->i_sb;
849 struct msdos_sb_info *sbi = MSDOS_SB(sb);
850 struct buffer_head *bh;
851 struct msdos_dir_entry *raw_entry;
852 loff_t i_pos;
853 sector_t blocknr;
854 int err, offset;
855
856 if (inode->i_ino == MSDOS_ROOT_INO)
857 return 0;
858
859retry:
860 i_pos = fat_i_pos_read(sbi, inode);
861 if (!i_pos)
862 return 0;
863
864 fat_get_blknr_offset(sbi, i_pos, &blocknr, &offset);
865 bh = sb_bread(sb, blocknr);
866 if (!bh) {
867 fat_msg(sb, KERN_ERR, "unable to read inode block "
868 "for updating (i_pos %lld)", i_pos);
869 return -EIO;
870 }
871 spin_lock(&sbi->inode_hash_lock);
872 if (i_pos != MSDOS_I(inode)->i_pos) {
873 spin_unlock(&sbi->inode_hash_lock);
874 brelse(bh);
875 goto retry;
876 }
877
878 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))[offset];
879 if (S_ISDIR(inode->i_mode))
880 raw_entry->size = 0;
881 else
882 raw_entry->size = cpu_to_le32(inode->i_size);
883 raw_entry->attr = fat_make_attrs(inode);
884 fat_set_start(raw_entry, MSDOS_I(inode)->i_logstart);
885 fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
886 &raw_entry->date, NULL);
887 if (sbi->options.isvfat) {
888 __le16 atime;
889 fat_time_unix2fat(sbi, &inode->i_atime, &atime,
890 &raw_entry->adate, NULL);
891 fat_time_unix2fat(sbi, &MSDOS_I(inode)->i_crtime, &raw_entry->ctime,
892 &raw_entry->cdate, &raw_entry->ctime_cs);
893 }
894 spin_unlock(&sbi->inode_hash_lock);
895 mark_buffer_dirty(bh);
896 err = 0;
897 if (wait)
898 err = sync_dirty_buffer(bh);
899 brelse(bh);
900 return err;
901}
902
903static int fat_write_inode(struct inode *inode, struct writeback_control *wbc)
904{
905 int err;
906
907 if (inode->i_ino == MSDOS_FSINFO_INO) {
908 struct super_block *sb = inode->i_sb;
909
910 mutex_lock(&MSDOS_SB(sb)->s_lock);
911 err = fat_clusters_flush(sb);
912 mutex_unlock(&MSDOS_SB(sb)->s_lock);
913 } else
914 err = __fat_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
915
916 return err;
917}
918
919int fat_sync_inode(struct inode *inode)
920{
921 return __fat_write_inode(inode, 1);
922}
923
924EXPORT_SYMBOL_GPL(fat_sync_inode);
925
926static int fat_show_options(struct seq_file *m, struct dentry *root);
927static const struct super_operations fat_sops = {
928 .alloc_inode = fat_alloc_inode,
929 .free_inode = fat_free_inode,
930 .write_inode = fat_write_inode,
931 .evict_inode = fat_evict_inode,
932 .put_super = fat_put_super,
933 .statfs = fat_statfs,
934 .remount_fs = fat_remount,
935
936 .show_options = fat_show_options,
937};
938
939static int fat_show_options(struct seq_file *m, struct dentry *root)
940{
941 struct msdos_sb_info *sbi = MSDOS_SB(root->d_sb);
942 struct fat_mount_options *opts = &sbi->options;
943 int isvfat = opts->isvfat;
944
945 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
946 seq_printf(m, ",uid=%u",
947 from_kuid_munged(&init_user_ns, opts->fs_uid));
948 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
949 seq_printf(m, ",gid=%u",
950 from_kgid_munged(&init_user_ns, opts->fs_gid));
951 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
952 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
953 if (opts->allow_utime)
954 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
955 if (sbi->nls_disk)
956 /* strip "cp" prefix from displayed option */
957 seq_printf(m, ",codepage=%s", &sbi->nls_disk->charset[2]);
958 if (isvfat) {
959 if (sbi->nls_io)
960 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
961
962 switch (opts->shortname) {
963 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
964 seq_puts(m, ",shortname=win95");
965 break;
966 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
967 seq_puts(m, ",shortname=winnt");
968 break;
969 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
970 seq_puts(m, ",shortname=mixed");
971 break;
972 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
973 seq_puts(m, ",shortname=lower");
974 break;
975 default:
976 seq_puts(m, ",shortname=unknown");
977 break;
978 }
979 }
980 if (opts->name_check != 'n')
981 seq_printf(m, ",check=%c", opts->name_check);
982 if (opts->usefree)
983 seq_puts(m, ",usefree");
984 if (opts->quiet)
985 seq_puts(m, ",quiet");
986 if (opts->showexec)
987 seq_puts(m, ",showexec");
988 if (opts->sys_immutable)
989 seq_puts(m, ",sys_immutable");
990 if (!isvfat) {
991 if (opts->dotsOK)
992 seq_puts(m, ",dotsOK=yes");
993 if (opts->nocase)
994 seq_puts(m, ",nocase");
995 } else {
996 if (opts->utf8)
997 seq_puts(m, ",utf8");
998 if (opts->unicode_xlate)
999 seq_puts(m, ",uni_xlate");
1000 if (!opts->numtail)
1001 seq_puts(m, ",nonumtail");
1002 if (opts->rodir)
1003 seq_puts(m, ",rodir");
1004 }
1005 if (opts->flush)
1006 seq_puts(m, ",flush");
1007 if (opts->tz_set) {
1008 if (opts->time_offset)
1009 seq_printf(m, ",time_offset=%d", opts->time_offset);
1010 else
1011 seq_puts(m, ",tz=UTC");
1012 }
1013 if (opts->errors == FAT_ERRORS_CONT)
1014 seq_puts(m, ",errors=continue");
1015 else if (opts->errors == FAT_ERRORS_PANIC)
1016 seq_puts(m, ",errors=panic");
1017 else
1018 seq_puts(m, ",errors=remount-ro");
1019 if (opts->nfs == FAT_NFS_NOSTALE_RO)
1020 seq_puts(m, ",nfs=nostale_ro");
1021 else if (opts->nfs)
1022 seq_puts(m, ",nfs=stale_rw");
1023 if (opts->discard)
1024 seq_puts(m, ",discard");
1025 if (opts->dos1xfloppy)
1026 seq_puts(m, ",dos1xfloppy");
1027
1028 return 0;
1029}
1030
1031enum {
1032 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
1033 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
1034 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
1035 Opt_immutable, Opt_dots, Opt_nodots,
1036 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
1037 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
1038 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
1039 Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
1040 Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
1041 Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err, Opt_dos1xfloppy,
1042};
1043
1044static const match_table_t fat_tokens = {
1045 {Opt_check_r, "check=relaxed"},
1046 {Opt_check_s, "check=strict"},
1047 {Opt_check_n, "check=normal"},
1048 {Opt_check_r, "check=r"},
1049 {Opt_check_s, "check=s"},
1050 {Opt_check_n, "check=n"},
1051 {Opt_uid, "uid=%u"},
1052 {Opt_gid, "gid=%u"},
1053 {Opt_umask, "umask=%o"},
1054 {Opt_dmask, "dmask=%o"},
1055 {Opt_fmask, "fmask=%o"},
1056 {Opt_allow_utime, "allow_utime=%o"},
1057 {Opt_codepage, "codepage=%u"},
1058 {Opt_usefree, "usefree"},
1059 {Opt_nocase, "nocase"},
1060 {Opt_quiet, "quiet"},
1061 {Opt_showexec, "showexec"},
1062 {Opt_debug, "debug"},
1063 {Opt_immutable, "sys_immutable"},
1064 {Opt_flush, "flush"},
1065 {Opt_tz_utc, "tz=UTC"},
1066 {Opt_time_offset, "time_offset=%d"},
1067 {Opt_err_cont, "errors=continue"},
1068 {Opt_err_panic, "errors=panic"},
1069 {Opt_err_ro, "errors=remount-ro"},
1070 {Opt_discard, "discard"},
1071 {Opt_nfs_stale_rw, "nfs"},
1072 {Opt_nfs_stale_rw, "nfs=stale_rw"},
1073 {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
1074 {Opt_dos1xfloppy, "dos1xfloppy"},
1075 {Opt_obsolete, "conv=binary"},
1076 {Opt_obsolete, "conv=text"},
1077 {Opt_obsolete, "conv=auto"},
1078 {Opt_obsolete, "conv=b"},
1079 {Opt_obsolete, "conv=t"},
1080 {Opt_obsolete, "conv=a"},
1081 {Opt_obsolete, "fat=%u"},
1082 {Opt_obsolete, "blocksize=%u"},
1083 {Opt_obsolete, "cvf_format=%20s"},
1084 {Opt_obsolete, "cvf_options=%100s"},
1085 {Opt_obsolete, "posix"},
1086 {Opt_err, NULL},
1087};
1088static const match_table_t msdos_tokens = {
1089 {Opt_nodots, "nodots"},
1090 {Opt_nodots, "dotsOK=no"},
1091 {Opt_dots, "dots"},
1092 {Opt_dots, "dotsOK=yes"},
1093 {Opt_err, NULL}
1094};
1095static const match_table_t vfat_tokens = {
1096 {Opt_charset, "iocharset=%s"},
1097 {Opt_shortname_lower, "shortname=lower"},
1098 {Opt_shortname_win95, "shortname=win95"},
1099 {Opt_shortname_winnt, "shortname=winnt"},
1100 {Opt_shortname_mixed, "shortname=mixed"},
1101 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
1102 {Opt_utf8_no, "utf8=no"},
1103 {Opt_utf8_no, "utf8=false"},
1104 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
1105 {Opt_utf8_yes, "utf8=yes"},
1106 {Opt_utf8_yes, "utf8=true"},
1107 {Opt_utf8_yes, "utf8"},
1108 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
1109 {Opt_uni_xl_no, "uni_xlate=no"},
1110 {Opt_uni_xl_no, "uni_xlate=false"},
1111 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
1112 {Opt_uni_xl_yes, "uni_xlate=yes"},
1113 {Opt_uni_xl_yes, "uni_xlate=true"},
1114 {Opt_uni_xl_yes, "uni_xlate"},
1115 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
1116 {Opt_nonumtail_no, "nonumtail=no"},
1117 {Opt_nonumtail_no, "nonumtail=false"},
1118 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
1119 {Opt_nonumtail_yes, "nonumtail=yes"},
1120 {Opt_nonumtail_yes, "nonumtail=true"},
1121 {Opt_nonumtail_yes, "nonumtail"},
1122 {Opt_rodir, "rodir"},
1123 {Opt_err, NULL}
1124};
1125
1126static int parse_options(struct super_block *sb, char *options, int is_vfat,
1127 int silent, int *debug, struct fat_mount_options *opts)
1128{
1129 char *p;
1130 substring_t args[MAX_OPT_ARGS];
1131 int option;
1132 char *iocharset;
1133
1134 opts->isvfat = is_vfat;
1135
1136 opts->fs_uid = current_uid();
1137 opts->fs_gid = current_gid();
1138 opts->fs_fmask = opts->fs_dmask = current_umask();
1139 opts->allow_utime = -1;
1140 opts->codepage = fat_default_codepage;
1141 fat_reset_iocharset(opts);
1142 if (is_vfat) {
1143 opts->shortname = VFAT_SFN_DISPLAY_WINNT|VFAT_SFN_CREATE_WIN95;
1144 opts->rodir = 0;
1145 } else {
1146 opts->shortname = 0;
1147 opts->rodir = 1;
1148 }
1149 opts->name_check = 'n';
1150 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
1151 opts->unicode_xlate = 0;
1152 opts->numtail = 1;
1153 opts->usefree = opts->nocase = 0;
1154 opts->tz_set = 0;
1155 opts->nfs = 0;
1156 opts->errors = FAT_ERRORS_RO;
1157 *debug = 0;
1158
1159 opts->utf8 = IS_ENABLED(CONFIG_FAT_DEFAULT_UTF8) && is_vfat;
1160
1161 if (!options)
1162 goto out;
1163
1164 while ((p = strsep(&options, ",")) != NULL) {
1165 int token;
1166 if (!*p)
1167 continue;
1168
1169 token = match_token(p, fat_tokens, args);
1170 if (token == Opt_err) {
1171 if (is_vfat)
1172 token = match_token(p, vfat_tokens, args);
1173 else
1174 token = match_token(p, msdos_tokens, args);
1175 }
1176 switch (token) {
1177 case Opt_check_s:
1178 opts->name_check = 's';
1179 break;
1180 case Opt_check_r:
1181 opts->name_check = 'r';
1182 break;
1183 case Opt_check_n:
1184 opts->name_check = 'n';
1185 break;
1186 case Opt_usefree:
1187 opts->usefree = 1;
1188 break;
1189 case Opt_nocase:
1190 if (!is_vfat)
1191 opts->nocase = 1;
1192 else {
1193 /* for backward compatibility */
1194 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1195 | VFAT_SFN_CREATE_WIN95;
1196 }
1197 break;
1198 case Opt_quiet:
1199 opts->quiet = 1;
1200 break;
1201 case Opt_showexec:
1202 opts->showexec = 1;
1203 break;
1204 case Opt_debug:
1205 *debug = 1;
1206 break;
1207 case Opt_immutable:
1208 opts->sys_immutable = 1;
1209 break;
1210 case Opt_uid:
1211 if (match_int(&args[0], &option))
1212 return -EINVAL;
1213 opts->fs_uid = make_kuid(current_user_ns(), option);
1214 if (!uid_valid(opts->fs_uid))
1215 return -EINVAL;
1216 break;
1217 case Opt_gid:
1218 if (match_int(&args[0], &option))
1219 return -EINVAL;
1220 opts->fs_gid = make_kgid(current_user_ns(), option);
1221 if (!gid_valid(opts->fs_gid))
1222 return -EINVAL;
1223 break;
1224 case Opt_umask:
1225 if (match_octal(&args[0], &option))
1226 return -EINVAL;
1227 opts->fs_fmask = opts->fs_dmask = option;
1228 break;
1229 case Opt_dmask:
1230 if (match_octal(&args[0], &option))
1231 return -EINVAL;
1232 opts->fs_dmask = option;
1233 break;
1234 case Opt_fmask:
1235 if (match_octal(&args[0], &option))
1236 return -EINVAL;
1237 opts->fs_fmask = option;
1238 break;
1239 case Opt_allow_utime:
1240 if (match_octal(&args[0], &option))
1241 return -EINVAL;
1242 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1243 break;
1244 case Opt_codepage:
1245 if (match_int(&args[0], &option))
1246 return -EINVAL;
1247 opts->codepage = option;
1248 break;
1249 case Opt_flush:
1250 opts->flush = 1;
1251 break;
1252 case Opt_time_offset:
1253 if (match_int(&args[0], &option))
1254 return -EINVAL;
1255 /*
1256 * GMT+-12 zones may have DST corrections so at least
1257 * 13 hours difference is needed. Make the limit 24
1258 * just in case someone invents something unusual.
1259 */
1260 if (option < -24 * 60 || option > 24 * 60)
1261 return -EINVAL;
1262 opts->tz_set = 1;
1263 opts->time_offset = option;
1264 break;
1265 case Opt_tz_utc:
1266 opts->tz_set = 1;
1267 opts->time_offset = 0;
1268 break;
1269 case Opt_err_cont:
1270 opts->errors = FAT_ERRORS_CONT;
1271 break;
1272 case Opt_err_panic:
1273 opts->errors = FAT_ERRORS_PANIC;
1274 break;
1275 case Opt_err_ro:
1276 opts->errors = FAT_ERRORS_RO;
1277 break;
1278 case Opt_nfs_stale_rw:
1279 opts->nfs = FAT_NFS_STALE_RW;
1280 break;
1281 case Opt_nfs_nostale_ro:
1282 opts->nfs = FAT_NFS_NOSTALE_RO;
1283 break;
1284 case Opt_dos1xfloppy:
1285 opts->dos1xfloppy = 1;
1286 break;
1287
1288 /* msdos specific */
1289 case Opt_dots:
1290 opts->dotsOK = 1;
1291 break;
1292 case Opt_nodots:
1293 opts->dotsOK = 0;
1294 break;
1295
1296 /* vfat specific */
1297 case Opt_charset:
1298 fat_reset_iocharset(opts);
1299 iocharset = match_strdup(&args[0]);
1300 if (!iocharset)
1301 return -ENOMEM;
1302 opts->iocharset = iocharset;
1303 break;
1304 case Opt_shortname_lower:
1305 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1306 | VFAT_SFN_CREATE_WIN95;
1307 break;
1308 case Opt_shortname_win95:
1309 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1310 | VFAT_SFN_CREATE_WIN95;
1311 break;
1312 case Opt_shortname_winnt:
1313 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1314 | VFAT_SFN_CREATE_WINNT;
1315 break;
1316 case Opt_shortname_mixed:
1317 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1318 | VFAT_SFN_CREATE_WIN95;
1319 break;
1320 case Opt_utf8_no: /* 0 or no or false */
1321 opts->utf8 = 0;
1322 break;
1323 case Opt_utf8_yes: /* empty or 1 or yes or true */
1324 opts->utf8 = 1;
1325 break;
1326 case Opt_uni_xl_no: /* 0 or no or false */
1327 opts->unicode_xlate = 0;
1328 break;
1329 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1330 opts->unicode_xlate = 1;
1331 break;
1332 case Opt_nonumtail_no: /* 0 or no or false */
1333 opts->numtail = 1; /* negated option */
1334 break;
1335 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1336 opts->numtail = 0; /* negated option */
1337 break;
1338 case Opt_rodir:
1339 opts->rodir = 1;
1340 break;
1341 case Opt_discard:
1342 opts->discard = 1;
1343 break;
1344
1345 /* obsolete mount options */
1346 case Opt_obsolete:
1347 fat_msg(sb, KERN_INFO, "\"%s\" option is obsolete, "
1348 "not supported now", p);
1349 break;
1350 /* unknown option */
1351 default:
1352 if (!silent) {
1353 fat_msg(sb, KERN_ERR,
1354 "Unrecognized mount option \"%s\" "
1355 "or missing value", p);
1356 }
1357 return -EINVAL;
1358 }
1359 }
1360
1361out:
1362 /* UTF-8 doesn't provide FAT semantics */
1363 if (!strcmp(opts->iocharset, "utf8")) {
1364 fat_msg(sb, KERN_WARNING, "utf8 is not a recommended IO charset"
1365 " for FAT filesystems, filesystem will be "
1366 "case sensitive!");
1367 }
1368
1369 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1370 if (opts->allow_utime == (unsigned short)-1)
1371 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1372 if (opts->unicode_xlate)
1373 opts->utf8 = 0;
1374 if (opts->nfs == FAT_NFS_NOSTALE_RO) {
1375 sb->s_flags |= SB_RDONLY;
1376 sb->s_export_op = &fat_export_ops_nostale;
1377 }
1378
1379 return 0;
1380}
1381
1382static int fat_read_root(struct inode *inode)
1383{
1384 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
1385 int error;
1386
1387 MSDOS_I(inode)->i_pos = MSDOS_ROOT_INO;
1388 inode->i_uid = sbi->options.fs_uid;
1389 inode->i_gid = sbi->options.fs_gid;
1390 inode_inc_iversion(inode);
1391 inode->i_generation = 0;
1392 inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
1393 inode->i_op = sbi->dir_ops;
1394 inode->i_fop = &fat_dir_operations;
1395 if (is_fat32(sbi)) {
1396 MSDOS_I(inode)->i_start = sbi->root_cluster;
1397 error = fat_calc_dir_size(inode);
1398 if (error < 0)
1399 return error;
1400 } else {
1401 MSDOS_I(inode)->i_start = 0;
1402 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1403 }
1404 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1405 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1406 MSDOS_I(inode)->i_logstart = 0;
1407 MSDOS_I(inode)->mmu_private = inode->i_size;
1408
1409 fat_save_attrs(inode, ATTR_DIR);
1410 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1411 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1412 set_nlink(inode, fat_subdirs(inode)+2);
1413
1414 return 0;
1415}
1416
1417static unsigned long calc_fat_clusters(struct super_block *sb)
1418{
1419 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1420
1421 /* Divide first to avoid overflow */
1422 if (!is_fat12(sbi)) {
1423 unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
1424 return ent_per_sec * sbi->fat_length;
1425 }
1426
1427 return sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1428}
1429
1430static bool fat_bpb_is_zero(struct fat_boot_sector *b)
1431{
1432 if (get_unaligned_le16(&b->sector_size))
1433 return false;
1434 if (b->sec_per_clus)
1435 return false;
1436 if (b->reserved)
1437 return false;
1438 if (b->fats)
1439 return false;
1440 if (get_unaligned_le16(&b->dir_entries))
1441 return false;
1442 if (get_unaligned_le16(&b->sectors))
1443 return false;
1444 if (b->media)
1445 return false;
1446 if (b->fat_length)
1447 return false;
1448 if (b->secs_track)
1449 return false;
1450 if (b->heads)
1451 return false;
1452 return true;
1453}
1454
1455static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b,
1456 int silent, struct fat_bios_param_block *bpb)
1457{
1458 int error = -EINVAL;
1459
1460 /* Read in BPB ... */
1461 memset(bpb, 0, sizeof(*bpb));
1462 bpb->fat_sector_size = get_unaligned_le16(&b->sector_size);
1463 bpb->fat_sec_per_clus = b->sec_per_clus;
1464 bpb->fat_reserved = le16_to_cpu(b->reserved);
1465 bpb->fat_fats = b->fats;
1466 bpb->fat_dir_entries = get_unaligned_le16(&b->dir_entries);
1467 bpb->fat_sectors = get_unaligned_le16(&b->sectors);
1468 bpb->fat_fat_length = le16_to_cpu(b->fat_length);
1469 bpb->fat_total_sect = le32_to_cpu(b->total_sect);
1470
1471 bpb->fat16_state = b->fat16.state;
1472 bpb->fat16_vol_id = get_unaligned_le32(b->fat16.vol_id);
1473
1474 bpb->fat32_length = le32_to_cpu(b->fat32.length);
1475 bpb->fat32_root_cluster = le32_to_cpu(b->fat32.root_cluster);
1476 bpb->fat32_info_sector = le16_to_cpu(b->fat32.info_sector);
1477 bpb->fat32_state = b->fat32.state;
1478 bpb->fat32_vol_id = get_unaligned_le32(b->fat32.vol_id);
1479
1480 /* Validate this looks like a FAT filesystem BPB */
1481 if (!bpb->fat_reserved) {
1482 if (!silent)
1483 fat_msg(sb, KERN_ERR,
1484 "bogus number of reserved sectors");
1485 goto out;
1486 }
1487 if (!bpb->fat_fats) {
1488 if (!silent)
1489 fat_msg(sb, KERN_ERR, "bogus number of FAT structure");
1490 goto out;
1491 }
1492
1493 /*
1494 * Earlier we checked here that b->secs_track and b->head are nonzero,
1495 * but it turns out valid FAT filesystems can have zero there.
1496 */
1497
1498 if (!fat_valid_media(b->media)) {
1499 if (!silent)
1500 fat_msg(sb, KERN_ERR, "invalid media value (0x%02x)",
1501 (unsigned)b->media);
1502 goto out;
1503 }
1504
1505 if (!is_power_of_2(bpb->fat_sector_size)
1506 || (bpb->fat_sector_size < 512)
1507 || (bpb->fat_sector_size > 4096)) {
1508 if (!silent)
1509 fat_msg(sb, KERN_ERR, "bogus logical sector size %u",
1510 (unsigned)bpb->fat_sector_size);
1511 goto out;
1512 }
1513
1514 if (!is_power_of_2(bpb->fat_sec_per_clus)) {
1515 if (!silent)
1516 fat_msg(sb, KERN_ERR, "bogus sectors per cluster %u",
1517 (unsigned)bpb->fat_sec_per_clus);
1518 goto out;
1519 }
1520
1521 if (bpb->fat_fat_length == 0 && bpb->fat32_length == 0) {
1522 if (!silent)
1523 fat_msg(sb, KERN_ERR, "bogus number of FAT sectors");
1524 goto out;
1525 }
1526
1527 error = 0;
1528
1529out:
1530 return error;
1531}
1532
1533static int fat_read_static_bpb(struct super_block *sb,
1534 struct fat_boot_sector *b, int silent,
1535 struct fat_bios_param_block *bpb)
1536{
1537 static const char *notdos1x = "This doesn't look like a DOS 1.x volume";
1538 sector_t bd_sects = bdev_nr_sectors(sb->s_bdev);
1539 struct fat_floppy_defaults *fdefaults = NULL;
1540 int error = -EINVAL;
1541 unsigned i;
1542
1543 /* 16-bit DOS 1.x reliably wrote bootstrap short-jmp code */
1544 if (b->ignored[0] != 0xeb || b->ignored[2] != 0x90) {
1545 if (!silent)
1546 fat_msg(sb, KERN_ERR,
1547 "%s; no bootstrapping code", notdos1x);
1548 goto out;
1549 }
1550
1551 /*
1552 * If any value in this region is non-zero, it isn't archaic
1553 * DOS.
1554 */
1555 if (!fat_bpb_is_zero(b)) {
1556 if (!silent)
1557 fat_msg(sb, KERN_ERR,
1558 "%s; DOS 2.x BPB is non-zero", notdos1x);
1559 goto out;
1560 }
1561
1562 for (i = 0; i < ARRAY_SIZE(floppy_defaults); i++) {
1563 if (floppy_defaults[i].nr_sectors == bd_sects) {
1564 fdefaults = &floppy_defaults[i];
1565 break;
1566 }
1567 }
1568
1569 if (fdefaults == NULL) {
1570 if (!silent)
1571 fat_msg(sb, KERN_WARNING,
1572 "This looks like a DOS 1.x volume, but isn't a recognized floppy size (%llu sectors)",
1573 (u64)bd_sects);
1574 goto out;
1575 }
1576
1577 if (!silent)
1578 fat_msg(sb, KERN_INFO,
1579 "This looks like a DOS 1.x volume; assuming default BPB values");
1580
1581 memset(bpb, 0, sizeof(*bpb));
1582 bpb->fat_sector_size = SECTOR_SIZE;
1583 bpb->fat_sec_per_clus = fdefaults->sec_per_clus;
1584 bpb->fat_reserved = 1;
1585 bpb->fat_fats = 2;
1586 bpb->fat_dir_entries = fdefaults->dir_entries;
1587 bpb->fat_sectors = fdefaults->nr_sectors;
1588 bpb->fat_fat_length = fdefaults->fat_length;
1589
1590 error = 0;
1591
1592out:
1593 return error;
1594}
1595
1596/*
1597 * Read the super block of an MS-DOS FS.
1598 */
1599int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
1600 void (*setup)(struct super_block *))
1601{
1602 struct inode *root_inode = NULL, *fat_inode = NULL;
1603 struct inode *fsinfo_inode = NULL;
1604 struct buffer_head *bh;
1605 struct fat_bios_param_block bpb;
1606 struct msdos_sb_info *sbi;
1607 u16 logical_sector_size;
1608 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1609 int debug;
1610 long error;
1611 char buf[50];
1612 struct timespec64 ts;
1613
1614 /*
1615 * GFP_KERNEL is ok here, because while we do hold the
1616 * superblock lock, memory pressure can't call back into
1617 * the filesystem, since we're only just about to mount
1618 * it and have no inodes etc active!
1619 */
1620 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1621 if (!sbi)
1622 return -ENOMEM;
1623 sb->s_fs_info = sbi;
1624
1625 sb->s_flags |= SB_NODIRATIME;
1626 sb->s_magic = MSDOS_SUPER_MAGIC;
1627 sb->s_op = &fat_sops;
1628 sb->s_export_op = &fat_export_ops;
1629 /*
1630 * fat timestamps are complex and truncated by fat itself, so
1631 * we set 1 here to be fast
1632 */
1633 sb->s_time_gran = 1;
1634 mutex_init(&sbi->nfs_build_inode_lock);
1635 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
1636 DEFAULT_RATELIMIT_BURST);
1637
1638 error = parse_options(sb, data, isvfat, silent, &debug, &sbi->options);
1639 if (error)
1640 goto out_fail;
1641
1642 setup(sb); /* flavour-specific stuff that needs options */
1643
1644 error = -EIO;
1645 sb_min_blocksize(sb, 512);
1646 bh = sb_bread(sb, 0);
1647 if (bh == NULL) {
1648 fat_msg(sb, KERN_ERR, "unable to read boot sector");
1649 goto out_fail;
1650 }
1651
1652 error = fat_read_bpb(sb, (struct fat_boot_sector *)bh->b_data, silent,
1653 &bpb);
1654 if (error == -EINVAL && sbi->options.dos1xfloppy)
1655 error = fat_read_static_bpb(sb,
1656 (struct fat_boot_sector *)bh->b_data, silent, &bpb);
1657 brelse(bh);
1658
1659 if (error == -EINVAL)
1660 goto out_invalid;
1661 else if (error)
1662 goto out_fail;
1663
1664 logical_sector_size = bpb.fat_sector_size;
1665 sbi->sec_per_clus = bpb.fat_sec_per_clus;
1666
1667 error = -EIO;
1668 if (logical_sector_size < sb->s_blocksize) {
1669 fat_msg(sb, KERN_ERR, "logical sector size too small for device"
1670 " (logical sector size = %u)", logical_sector_size);
1671 goto out_fail;
1672 }
1673
1674 if (logical_sector_size > sb->s_blocksize) {
1675 struct buffer_head *bh_resize;
1676
1677 if (!sb_set_blocksize(sb, logical_sector_size)) {
1678 fat_msg(sb, KERN_ERR, "unable to set blocksize %u",
1679 logical_sector_size);
1680 goto out_fail;
1681 }
1682
1683 /* Verify that the larger boot sector is fully readable */
1684 bh_resize = sb_bread(sb, 0);
1685 if (bh_resize == NULL) {
1686 fat_msg(sb, KERN_ERR, "unable to read boot sector"
1687 " (logical sector size = %lu)",
1688 sb->s_blocksize);
1689 goto out_fail;
1690 }
1691 brelse(bh_resize);
1692 }
1693
1694 mutex_init(&sbi->s_lock);
1695 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1696 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1697 sbi->fats = bpb.fat_fats;
1698 sbi->fat_bits = 0; /* Don't know yet */
1699 sbi->fat_start = bpb.fat_reserved;
1700 sbi->fat_length = bpb.fat_fat_length;
1701 sbi->root_cluster = 0;
1702 sbi->free_clusters = -1; /* Don't know yet */
1703 sbi->free_clus_valid = 0;
1704 sbi->prev_free = FAT_START_ENT;
1705 sb->s_maxbytes = 0xffffffff;
1706 fat_time_fat2unix(sbi, &ts, 0, cpu_to_le16(FAT_DATE_MIN), 0);
1707 sb->s_time_min = ts.tv_sec;
1708
1709 fat_time_fat2unix(sbi, &ts, cpu_to_le16(FAT_TIME_MAX),
1710 cpu_to_le16(FAT_DATE_MAX), 0);
1711 sb->s_time_max = ts.tv_sec;
1712
1713 if (!sbi->fat_length && bpb.fat32_length) {
1714 struct fat_boot_fsinfo *fsinfo;
1715 struct buffer_head *fsinfo_bh;
1716
1717 /* Must be FAT32 */
1718 sbi->fat_bits = 32;
1719 sbi->fat_length = bpb.fat32_length;
1720 sbi->root_cluster = bpb.fat32_root_cluster;
1721
1722 /* MC - if info_sector is 0, don't multiply by 0 */
1723 sbi->fsinfo_sector = bpb.fat32_info_sector;
1724 if (sbi->fsinfo_sector == 0)
1725 sbi->fsinfo_sector = 1;
1726
1727 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1728 if (fsinfo_bh == NULL) {
1729 fat_msg(sb, KERN_ERR, "bread failed, FSINFO block"
1730 " (sector = %lu)", sbi->fsinfo_sector);
1731 goto out_fail;
1732 }
1733
1734 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1735 if (!IS_FSINFO(fsinfo)) {
1736 fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: "
1737 "0x%08x, 0x%08x (sector = %lu)",
1738 le32_to_cpu(fsinfo->signature1),
1739 le32_to_cpu(fsinfo->signature2),
1740 sbi->fsinfo_sector);
1741 } else {
1742 if (sbi->options.usefree)
1743 sbi->free_clus_valid = 1;
1744 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1745 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1746 }
1747
1748 brelse(fsinfo_bh);
1749 }
1750
1751 /* interpret volume ID as a little endian 32 bit integer */
1752 if (is_fat32(sbi))
1753 sbi->vol_id = bpb.fat32_vol_id;
1754 else /* fat 16 or 12 */
1755 sbi->vol_id = bpb.fat16_vol_id;
1756
1757 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1758 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1759
1760 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1761 sbi->dir_entries = bpb.fat_dir_entries;
1762 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1763 if (!silent)
1764 fat_msg(sb, KERN_ERR, "bogus number of directory entries"
1765 " (%u)", sbi->dir_entries);
1766 goto out_invalid;
1767 }
1768
1769 rootdir_sectors = sbi->dir_entries
1770 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1771 sbi->data_start = sbi->dir_start + rootdir_sectors;
1772 total_sectors = bpb.fat_sectors;
1773 if (total_sectors == 0)
1774 total_sectors = bpb.fat_total_sect;
1775
1776 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1777
1778 if (!is_fat32(sbi))
1779 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1780
1781 /* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
1782 if (is_fat32(sbi))
1783 sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
1784 else /* fat 16 or 12 */
1785 sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
1786
1787 /* check that FAT table does not overflow */
1788 fat_clusters = calc_fat_clusters(sb);
1789 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1790 if (total_clusters > max_fat(sb)) {
1791 if (!silent)
1792 fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
1793 total_clusters);
1794 goto out_invalid;
1795 }
1796
1797 sbi->max_cluster = total_clusters + FAT_START_ENT;
1798 /* check the free_clusters, it's not necessarily correct */
1799 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1800 sbi->free_clusters = -1;
1801 /* check the prev_free, it's not necessarily correct */
1802 sbi->prev_free %= sbi->max_cluster;
1803 if (sbi->prev_free < FAT_START_ENT)
1804 sbi->prev_free = FAT_START_ENT;
1805
1806 /* set up enough so that it can read an inode */
1807 fat_hash_init(sb);
1808 dir_hash_init(sb);
1809 fat_ent_access_init(sb);
1810
1811 /*
1812 * The low byte of the first FAT entry must have the same value as
1813 * the media field of the boot sector. But in real world, too many
1814 * devices are writing wrong values. So, removed that validity check.
1815 *
1816 * The removed check compared the first FAT entry to a value dependent
1817 * on the media field like this:
1818 * == (0x0F00 | media), for FAT12
1819 * == (0XFF00 | media), for FAT16
1820 * == (0x0FFFFF | media), for FAT32
1821 */
1822
1823 error = -EINVAL;
1824 sprintf(buf, "cp%d", sbi->options.codepage);
1825 sbi->nls_disk = load_nls(buf);
1826 if (!sbi->nls_disk) {
1827 fat_msg(sb, KERN_ERR, "codepage %s not found", buf);
1828 goto out_fail;
1829 }
1830
1831 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1832 if (sbi->options.isvfat) {
1833 sbi->nls_io = load_nls(sbi->options.iocharset);
1834 if (!sbi->nls_io) {
1835 fat_msg(sb, KERN_ERR, "IO charset %s not found",
1836 sbi->options.iocharset);
1837 goto out_fail;
1838 }
1839 }
1840
1841 error = -ENOMEM;
1842 fat_inode = new_inode(sb);
1843 if (!fat_inode)
1844 goto out_fail;
1845 sbi->fat_inode = fat_inode;
1846
1847 fsinfo_inode = new_inode(sb);
1848 if (!fsinfo_inode)
1849 goto out_fail;
1850 fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
1851 sbi->fsinfo_inode = fsinfo_inode;
1852 insert_inode_hash(fsinfo_inode);
1853
1854 root_inode = new_inode(sb);
1855 if (!root_inode)
1856 goto out_fail;
1857 root_inode->i_ino = MSDOS_ROOT_INO;
1858 inode_set_iversion(root_inode, 1);
1859 error = fat_read_root(root_inode);
1860 if (error < 0) {
1861 iput(root_inode);
1862 goto out_fail;
1863 }
1864 error = -ENOMEM;
1865 insert_inode_hash(root_inode);
1866 fat_attach(root_inode, 0);
1867 sb->s_root = d_make_root(root_inode);
1868 if (!sb->s_root) {
1869 fat_msg(sb, KERN_ERR, "get root inode failed");
1870 goto out_fail;
1871 }
1872
1873 if (sbi->options.discard && !bdev_max_discard_sectors(sb->s_bdev))
1874 fat_msg(sb, KERN_WARNING,
1875 "mounting with \"discard\" option, but the device does not support discard");
1876
1877 fat_set_state(sb, 1, 0);
1878 return 0;
1879
1880out_invalid:
1881 error = -EINVAL;
1882 if (!silent)
1883 fat_msg(sb, KERN_INFO, "Can't find a valid FAT filesystem");
1884
1885out_fail:
1886 iput(fsinfo_inode);
1887 iput(fat_inode);
1888 unload_nls(sbi->nls_io);
1889 unload_nls(sbi->nls_disk);
1890 fat_reset_iocharset(&sbi->options);
1891 sb->s_fs_info = NULL;
1892 kfree(sbi);
1893 return error;
1894}
1895
1896EXPORT_SYMBOL_GPL(fat_fill_super);
1897
1898/*
1899 * helper function for fat_flush_inodes. This writes both the inode
1900 * and the file data blocks, waiting for in flight data blocks before
1901 * the start of the call. It does not wait for any io started
1902 * during the call
1903 */
1904static int writeback_inode(struct inode *inode)
1905{
1906
1907 int ret;
1908
1909 /* if we used wait=1, sync_inode_metadata waits for the io for the
1910 * inode to finish. So wait=0 is sent down to sync_inode_metadata
1911 * and filemap_fdatawrite is used for the data blocks
1912 */
1913 ret = sync_inode_metadata(inode, 0);
1914 if (!ret)
1915 ret = filemap_fdatawrite(inode->i_mapping);
1916 return ret;
1917}
1918
1919/*
1920 * write data and metadata corresponding to i1 and i2. The io is
1921 * started but we do not wait for any of it to finish.
1922 *
1923 * filemap_flush is used for the block device, so if there is a dirty
1924 * page for a block already in flight, we will not wait and start the
1925 * io over again
1926 */
1927int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1928{
1929 int ret = 0;
1930 if (!MSDOS_SB(sb)->options.flush)
1931 return 0;
1932 if (i1)
1933 ret = writeback_inode(i1);
1934 if (!ret && i2)
1935 ret = writeback_inode(i2);
1936 if (!ret)
1937 ret = sync_blockdev_nowait(sb->s_bdev);
1938 return ret;
1939}
1940EXPORT_SYMBOL_GPL(fat_flush_inodes);
1941
1942static int __init init_fat_fs(void)
1943{
1944 int err;
1945
1946 err = fat_cache_init();
1947 if (err)
1948 return err;
1949
1950 err = fat_init_inodecache();
1951 if (err)
1952 goto failed;
1953
1954 return 0;
1955
1956failed:
1957 fat_cache_destroy();
1958 return err;
1959}
1960
1961static void __exit exit_fat_fs(void)
1962{
1963 fat_cache_destroy();
1964 fat_destroy_inodecache();
1965}
1966
1967module_init(init_fat_fs)
1968module_exit(exit_fat_fs)
1969
1970MODULE_LICENSE("GPL");