workqueues: add comments to __create_workqueue_key()
[linux-2.6/mini2440.git] / fs / fat / inode.c
blob6d266d793e2caba12ef6b65501ab1db116c50574
1 /*
2 * linux/fs/fat/inode.c
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
8 * Fixes:
10 * Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/time.h>
16 #include <linux/slab.h>
17 #include <linux/smp_lock.h>
18 #include <linux/seq_file.h>
19 #include <linux/msdos_fs.h>
20 #include <linux/pagemap.h>
21 #include <linux/mpage.h>
22 #include <linux/buffer_head.h>
23 #include <linux/exportfs.h>
24 #include <linux/mount.h>
25 #include <linux/vfs.h>
26 #include <linux/parser.h>
27 #include <linux/uio.h>
28 #include <linux/writeback.h>
29 #include <linux/log2.h>
30 #include <asm/unaligned.h>
32 #ifndef CONFIG_FAT_DEFAULT_IOCHARSET
33 /* if user don't select VFAT, this is undefined. */
34 #define CONFIG_FAT_DEFAULT_IOCHARSET ""
35 #endif
37 static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
38 static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
41 static int fat_add_cluster(struct inode *inode)
43 int err, cluster;
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;
56 static inline int __fat_get_block(struct inode *inode, sector_t iblock,
57 unsigned long *max_blocks,
58 struct buffer_head *bh_result, int create)
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;
66 err = fat_bmap(inode, iblock, &phys, &mapped_blocks);
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;
74 if (!create)
75 return 0;
77 if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
78 fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)",
79 MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
80 return -EIO;
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;
90 /* available blocks on this cluster */
91 mapped_blocks = sbi->sec_per_clus - offset;
93 *max_blocks = min(mapped_blocks, *max_blocks);
94 MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
96 err = fat_bmap(inode, iblock, &phys, &mapped_blocks);
97 if (err)
98 return err;
100 BUG_ON(!phys);
101 BUG_ON(*max_blocks != mapped_blocks);
102 set_buffer_new(bh_result);
103 map_bh(bh_result, sb, phys);
105 return 0;
108 static int fat_get_block(struct inode *inode, sector_t iblock,
109 struct buffer_head *bh_result, int create)
111 struct super_block *sb = inode->i_sb;
112 unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
113 int err;
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;
122 static int fat_writepage(struct page *page, struct writeback_control *wbc)
124 return block_write_full_page(page, fat_get_block, wbc);
127 static int fat_writepages(struct address_space *mapping,
128 struct writeback_control *wbc)
130 return mpage_writepages(mapping, wbc, fat_get_block);
133 static int fat_readpage(struct file *file, struct page *page)
135 return mpage_readpage(page, fat_get_block);
138 static int fat_readpages(struct file *file, struct address_space *mapping,
139 struct list_head *pages, unsigned nr_pages)
141 return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
144 static int fat_write_begin(struct file *file, struct address_space *mapping,
145 loff_t pos, unsigned len, unsigned flags,
146 struct page **pagep, void **fsdata)
148 *pagep = NULL;
149 return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
150 fat_get_block,
151 &MSDOS_I(mapping->host)->mmu_private);
154 static int fat_write_end(struct file *file, struct address_space *mapping,
155 loff_t pos, unsigned len, unsigned copied,
156 struct page *pagep, void *fsdata)
158 struct inode *inode = mapping->host;
159 int err;
160 err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
161 if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
162 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
163 MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
164 mark_inode_dirty(inode);
166 return err;
169 static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
170 const struct iovec *iov,
171 loff_t offset, unsigned long nr_segs)
173 struct file *file = iocb->ki_filp;
174 struct inode *inode = file->f_mapping->host;
176 if (rw == WRITE) {
178 * FIXME: blockdev_direct_IO() doesn't use ->prepare_write(),
179 * so we need to update the ->mmu_private to block boundary.
181 * But we must fill the remaining area or hole by nul for
182 * updating ->mmu_private.
184 * Return 0, and fallback to normal buffered write.
186 loff_t size = offset + iov_length(iov, nr_segs);
187 if (MSDOS_I(inode)->mmu_private < size)
188 return 0;
192 * FAT need to use the DIO_LOCKING for avoiding the race
193 * condition of fat_get_block() and ->truncate().
195 return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
196 offset, nr_segs, fat_get_block, NULL);
199 static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
201 return generic_block_bmap(mapping, block, fat_get_block);
204 static const struct address_space_operations fat_aops = {
205 .readpage = fat_readpage,
206 .readpages = fat_readpages,
207 .writepage = fat_writepage,
208 .writepages = fat_writepages,
209 .sync_page = block_sync_page,
210 .write_begin = fat_write_begin,
211 .write_end = fat_write_end,
212 .direct_IO = fat_direct_IO,
213 .bmap = _fat_bmap
217 * New FAT inode stuff. We do the following:
218 * a) i_ino is constant and has nothing with on-disk location.
219 * b) FAT manages its own cache of directory entries.
220 * c) *This* cache is indexed by on-disk location.
221 * d) inode has an associated directory entry, all right, but
222 * it may be unhashed.
223 * e) currently entries are stored within struct inode. That should
224 * change.
225 * f) we deal with races in the following way:
226 * 1. readdir() and lookup() do FAT-dir-cache lookup.
227 * 2. rename() unhashes the F-d-c entry and rehashes it in
228 * a new place.
229 * 3. unlink() and rmdir() unhash F-d-c entry.
230 * 4. fat_write_inode() checks whether the thing is unhashed.
231 * If it is we silently return. If it isn't we do bread(),
232 * check if the location is still valid and retry if it
233 * isn't. Otherwise we do changes.
234 * 5. Spinlock is used to protect hash/unhash/location check/lookup
235 * 6. fat_clear_inode() unhashes the F-d-c entry.
236 * 7. lookup() and readdir() do igrab() if they find a F-d-c entry
237 * and consider negative result as cache miss.
240 static void fat_hash_init(struct super_block *sb)
242 struct msdos_sb_info *sbi = MSDOS_SB(sb);
243 int i;
245 spin_lock_init(&sbi->inode_hash_lock);
246 for (i = 0; i < FAT_HASH_SIZE; i++)
247 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
250 static inline unsigned long fat_hash(struct super_block *sb, loff_t i_pos)
252 unsigned long tmp = (unsigned long)i_pos | (unsigned long) sb;
253 tmp = tmp + (tmp >> FAT_HASH_BITS) + (tmp >> FAT_HASH_BITS * 2);
254 return tmp & FAT_HASH_MASK;
257 void fat_attach(struct inode *inode, loff_t i_pos)
259 struct super_block *sb = inode->i_sb;
260 struct msdos_sb_info *sbi = MSDOS_SB(sb);
262 spin_lock(&sbi->inode_hash_lock);
263 MSDOS_I(inode)->i_pos = i_pos;
264 hlist_add_head(&MSDOS_I(inode)->i_fat_hash,
265 sbi->inode_hashtable + fat_hash(sb, i_pos));
266 spin_unlock(&sbi->inode_hash_lock);
269 EXPORT_SYMBOL_GPL(fat_attach);
271 void fat_detach(struct inode *inode)
273 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
274 spin_lock(&sbi->inode_hash_lock);
275 MSDOS_I(inode)->i_pos = 0;
276 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
277 spin_unlock(&sbi->inode_hash_lock);
280 EXPORT_SYMBOL_GPL(fat_detach);
282 struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
284 struct msdos_sb_info *sbi = MSDOS_SB(sb);
285 struct hlist_head *head = sbi->inode_hashtable + fat_hash(sb, i_pos);
286 struct hlist_node *_p;
287 struct msdos_inode_info *i;
288 struct inode *inode = NULL;
290 spin_lock(&sbi->inode_hash_lock);
291 hlist_for_each_entry(i, _p, head, i_fat_hash) {
292 BUG_ON(i->vfs_inode.i_sb != sb);
293 if (i->i_pos != i_pos)
294 continue;
295 inode = igrab(&i->vfs_inode);
296 if (inode)
297 break;
299 spin_unlock(&sbi->inode_hash_lock);
300 return inode;
303 static int is_exec(unsigned char *extension)
305 unsigned char *exe_extensions = "EXECOMBAT", *walk;
307 for (walk = exe_extensions; *walk; walk += 3)
308 if (!strncmp(extension, walk, 3))
309 return 1;
310 return 0;
313 static int fat_calc_dir_size(struct inode *inode)
315 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
316 int ret, fclus, dclus;
318 inode->i_size = 0;
319 if (MSDOS_I(inode)->i_start == 0)
320 return 0;
322 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
323 if (ret < 0)
324 return ret;
325 inode->i_size = (fclus + 1) << sbi->cluster_bits;
327 return 0;
330 /* doesn't deal with root inode */
331 static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
333 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
334 int error;
336 MSDOS_I(inode)->i_pos = 0;
337 inode->i_uid = sbi->options.fs_uid;
338 inode->i_gid = sbi->options.fs_gid;
339 inode->i_version++;
340 inode->i_generation = get_seconds();
342 if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
343 inode->i_generation &= ~1;
344 inode->i_mode = MSDOS_MKMODE(de->attr,
345 S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR;
346 inode->i_op = sbi->dir_ops;
347 inode->i_fop = &fat_dir_operations;
349 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
350 if (sbi->fat_bits == 32)
351 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
353 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
354 error = fat_calc_dir_size(inode);
355 if (error < 0)
356 return error;
357 MSDOS_I(inode)->mmu_private = inode->i_size;
359 inode->i_nlink = fat_subdirs(inode);
360 } else { /* not a directory */
361 inode->i_generation |= 1;
362 inode->i_mode = MSDOS_MKMODE(de->attr,
363 ((sbi->options.showexec && !is_exec(de->name + 8))
364 ? S_IRUGO|S_IWUGO : S_IRWXUGO)
365 & ~sbi->options.fs_fmask) | S_IFREG;
366 MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
367 if (sbi->fat_bits == 32)
368 MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
370 MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
371 inode->i_size = le32_to_cpu(de->size);
372 inode->i_op = &fat_file_inode_operations;
373 inode->i_fop = &fat_file_operations;
374 inode->i_mapping->a_ops = &fat_aops;
375 MSDOS_I(inode)->mmu_private = inode->i_size;
377 if (de->attr & ATTR_SYS) {
378 if (sbi->options.sys_immutable)
379 inode->i_flags |= S_IMMUTABLE;
381 MSDOS_I(inode)->i_attrs = de->attr & ATTR_UNUSED;
382 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
383 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
384 inode->i_mtime.tv_sec =
385 date_dos2unix(le16_to_cpu(de->time), le16_to_cpu(de->date),
386 sbi->options.tz_utc);
387 inode->i_mtime.tv_nsec = 0;
388 if (sbi->options.isvfat) {
389 int secs = de->ctime_cs / 100;
390 int csecs = de->ctime_cs % 100;
391 inode->i_ctime.tv_sec =
392 date_dos2unix(le16_to_cpu(de->ctime),
393 le16_to_cpu(de->cdate),
394 sbi->options.tz_utc) + secs;
395 inode->i_ctime.tv_nsec = csecs * 10000000;
396 inode->i_atime.tv_sec =
397 date_dos2unix(0, le16_to_cpu(de->adate),
398 sbi->options.tz_utc);
399 inode->i_atime.tv_nsec = 0;
400 } else
401 inode->i_ctime = inode->i_atime = inode->i_mtime;
403 return 0;
406 struct inode *fat_build_inode(struct super_block *sb,
407 struct msdos_dir_entry *de, loff_t i_pos)
409 struct inode *inode;
410 int err;
412 inode = fat_iget(sb, i_pos);
413 if (inode)
414 goto out;
415 inode = new_inode(sb);
416 if (!inode) {
417 inode = ERR_PTR(-ENOMEM);
418 goto out;
420 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
421 inode->i_version = 1;
422 err = fat_fill_inode(inode, de);
423 if (err) {
424 iput(inode);
425 inode = ERR_PTR(err);
426 goto out;
428 fat_attach(inode, i_pos);
429 insert_inode_hash(inode);
430 out:
431 return inode;
434 EXPORT_SYMBOL_GPL(fat_build_inode);
436 static void fat_delete_inode(struct inode *inode)
438 truncate_inode_pages(&inode->i_data, 0);
439 inode->i_size = 0;
440 fat_truncate(inode);
441 clear_inode(inode);
444 static void fat_clear_inode(struct inode *inode)
446 struct super_block *sb = inode->i_sb;
447 struct msdos_sb_info *sbi = MSDOS_SB(sb);
449 spin_lock(&sbi->inode_hash_lock);
450 fat_cache_inval_inode(inode);
451 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
452 spin_unlock(&sbi->inode_hash_lock);
455 static void fat_write_super(struct super_block *sb)
457 sb->s_dirt = 0;
459 if (!(sb->s_flags & MS_RDONLY))
460 fat_clusters_flush(sb);
463 static void fat_put_super(struct super_block *sb)
465 struct msdos_sb_info *sbi = MSDOS_SB(sb);
467 if (sbi->nls_disk) {
468 unload_nls(sbi->nls_disk);
469 sbi->nls_disk = NULL;
470 sbi->options.codepage = fat_default_codepage;
472 if (sbi->nls_io) {
473 unload_nls(sbi->nls_io);
474 sbi->nls_io = NULL;
476 if (sbi->options.iocharset != fat_default_iocharset) {
477 kfree(sbi->options.iocharset);
478 sbi->options.iocharset = fat_default_iocharset;
481 sb->s_fs_info = NULL;
482 kfree(sbi);
485 static struct kmem_cache *fat_inode_cachep;
487 static struct inode *fat_alloc_inode(struct super_block *sb)
489 struct msdos_inode_info *ei;
490 ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
491 if (!ei)
492 return NULL;
493 return &ei->vfs_inode;
496 static void fat_destroy_inode(struct inode *inode)
498 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
501 static void init_once(void *foo)
503 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
505 spin_lock_init(&ei->cache_lru_lock);
506 ei->nr_caches = 0;
507 ei->cache_valid_id = FAT_CACHE_VALID + 1;
508 INIT_LIST_HEAD(&ei->cache_lru);
509 INIT_HLIST_NODE(&ei->i_fat_hash);
510 inode_init_once(&ei->vfs_inode);
513 static int __init fat_init_inodecache(void)
515 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
516 sizeof(struct msdos_inode_info),
517 0, (SLAB_RECLAIM_ACCOUNT|
518 SLAB_MEM_SPREAD),
519 init_once);
520 if (fat_inode_cachep == NULL)
521 return -ENOMEM;
522 return 0;
525 static void __exit fat_destroy_inodecache(void)
527 kmem_cache_destroy(fat_inode_cachep);
530 static int fat_remount(struct super_block *sb, int *flags, char *data)
532 struct msdos_sb_info *sbi = MSDOS_SB(sb);
533 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
534 return 0;
537 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
539 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
541 /* If the count of free cluster is still unknown, counts it here. */
542 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
543 int err = fat_count_free_clusters(dentry->d_sb);
544 if (err)
545 return err;
548 buf->f_type = dentry->d_sb->s_magic;
549 buf->f_bsize = sbi->cluster_size;
550 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
551 buf->f_bfree = sbi->free_clusters;
552 buf->f_bavail = sbi->free_clusters;
553 buf->f_namelen = sbi->options.isvfat ? 260 : 12;
555 return 0;
558 static int fat_write_inode(struct inode *inode, int wait)
560 struct super_block *sb = inode->i_sb;
561 struct msdos_sb_info *sbi = MSDOS_SB(sb);
562 struct buffer_head *bh;
563 struct msdos_dir_entry *raw_entry;
564 loff_t i_pos;
565 int err = 0;
567 retry:
568 i_pos = MSDOS_I(inode)->i_pos;
569 if (inode->i_ino == MSDOS_ROOT_INO || !i_pos)
570 return 0;
572 lock_super(sb);
573 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
574 if (!bh) {
575 printk(KERN_ERR "FAT: unable to read inode block "
576 "for updating (i_pos %lld)\n", i_pos);
577 err = -EIO;
578 goto out;
580 spin_lock(&sbi->inode_hash_lock);
581 if (i_pos != MSDOS_I(inode)->i_pos) {
582 spin_unlock(&sbi->inode_hash_lock);
583 brelse(bh);
584 unlock_super(sb);
585 goto retry;
588 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
589 [i_pos & (sbi->dir_per_block - 1)];
590 if (S_ISDIR(inode->i_mode))
591 raw_entry->size = 0;
592 else
593 raw_entry->size = cpu_to_le32(inode->i_size);
594 raw_entry->attr = fat_attr(inode);
595 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
596 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
597 fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time,
598 &raw_entry->date, sbi->options.tz_utc);
599 if (sbi->options.isvfat) {
600 __le16 atime;
601 fat_date_unix2dos(inode->i_ctime.tv_sec, &raw_entry->ctime,
602 &raw_entry->cdate, sbi->options.tz_utc);
603 fat_date_unix2dos(inode->i_atime.tv_sec, &atime,
604 &raw_entry->adate, sbi->options.tz_utc);
605 raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 +
606 inode->i_ctime.tv_nsec / 10000000;
608 spin_unlock(&sbi->inode_hash_lock);
609 mark_buffer_dirty(bh);
610 if (wait)
611 err = sync_dirty_buffer(bh);
612 brelse(bh);
613 out:
614 unlock_super(sb);
615 return err;
618 int fat_sync_inode(struct inode *inode)
620 return fat_write_inode(inode, 1);
623 EXPORT_SYMBOL_GPL(fat_sync_inode);
625 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt);
626 static const struct super_operations fat_sops = {
627 .alloc_inode = fat_alloc_inode,
628 .destroy_inode = fat_destroy_inode,
629 .write_inode = fat_write_inode,
630 .delete_inode = fat_delete_inode,
631 .put_super = fat_put_super,
632 .write_super = fat_write_super,
633 .statfs = fat_statfs,
634 .clear_inode = fat_clear_inode,
635 .remount_fs = fat_remount,
637 .show_options = fat_show_options,
641 * a FAT file handle with fhtype 3 is
642 * 0/ i_ino - for fast, reliable lookup if still in the cache
643 * 1/ i_generation - to see if i_ino is still valid
644 * bit 0 == 0 iff directory
645 * 2/ i_pos(8-39) - if ino has changed, but still in cache
646 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
647 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
649 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
650 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
651 * of i_logstart is used to store the directory entry offset.
654 static struct dentry *fat_fh_to_dentry(struct super_block *sb,
655 struct fid *fid, int fh_len, int fh_type)
657 struct inode *inode = NULL;
658 struct dentry *result;
659 u32 *fh = fid->raw;
661 if (fh_len < 5 || fh_type != 3)
662 return NULL;
664 inode = ilookup(sb, fh[0]);
665 if (!inode || inode->i_generation != fh[1]) {
666 if (inode)
667 iput(inode);
668 inode = NULL;
670 if (!inode) {
671 loff_t i_pos;
672 int i_logstart = fh[3] & 0x0fffffff;
674 i_pos = (loff_t)fh[2] << 8;
675 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);
677 /* try 2 - see if i_pos is in F-d-c
678 * require i_logstart to be the same
679 * Will fail if you truncate and then re-write
682 inode = fat_iget(sb, i_pos);
683 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
684 iput(inode);
685 inode = NULL;
688 if (!inode) {
689 /* For now, do nothing
690 * What we could do is:
691 * follow the file starting at fh[4], and record
692 * the ".." entry, and the name of the fh[2] entry.
693 * The follow the ".." file finding the next step up.
694 * This way we build a path to the root of
695 * the tree. If this works, we lookup the path and so
696 * get this inode into the cache.
697 * Finally try the fat_iget lookup again
698 * If that fails, then weare totally out of luck
699 * But all that is for another day
702 if (!inode)
703 return ERR_PTR(-ESTALE);
706 /* now to find a dentry.
707 * If possible, get a well-connected one
709 result = d_alloc_anon(inode);
710 if (result == NULL) {
711 iput(inode);
712 return ERR_PTR(-ENOMEM);
714 result->d_op = sb->s_root->d_op;
715 return result;
718 static int
719 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
721 int len = *lenp;
722 struct inode *inode = de->d_inode;
723 u32 ipos_h, ipos_m, ipos_l;
725 if (len < 5)
726 return 255; /* no room */
728 ipos_h = MSDOS_I(inode)->i_pos >> 8;
729 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
730 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28;
731 *lenp = 5;
732 fh[0] = inode->i_ino;
733 fh[1] = inode->i_generation;
734 fh[2] = ipos_h;
735 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart;
736 spin_lock(&de->d_lock);
737 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart;
738 spin_unlock(&de->d_lock);
739 return 3;
742 static struct dentry *fat_get_parent(struct dentry *child)
744 struct super_block *sb = child->d_sb;
745 struct buffer_head *bh;
746 struct msdos_dir_entry *de;
747 loff_t i_pos;
748 struct dentry *parent;
749 struct inode *inode;
750 int err;
752 lock_super(sb);
754 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos);
755 if (err) {
756 parent = ERR_PTR(err);
757 goto out;
759 inode = fat_build_inode(sb, de, i_pos);
760 brelse(bh);
761 if (IS_ERR(inode)) {
762 parent = ERR_CAST(inode);
763 goto out;
765 parent = d_alloc_anon(inode);
766 if (!parent) {
767 iput(inode);
768 parent = ERR_PTR(-ENOMEM);
770 out:
771 unlock_super(sb);
773 return parent;
776 static const struct export_operations fat_export_ops = {
777 .encode_fh = fat_encode_fh,
778 .fh_to_dentry = fat_fh_to_dentry,
779 .get_parent = fat_get_parent,
782 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
784 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb);
785 struct fat_mount_options *opts = &sbi->options;
786 int isvfat = opts->isvfat;
788 if (opts->fs_uid != 0)
789 seq_printf(m, ",uid=%u", opts->fs_uid);
790 if (opts->fs_gid != 0)
791 seq_printf(m, ",gid=%u", opts->fs_gid);
792 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
793 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
794 if (opts->allow_utime)
795 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
796 if (sbi->nls_disk)
797 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset);
798 if (isvfat) {
799 if (sbi->nls_io)
800 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
802 switch (opts->shortname) {
803 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
804 seq_puts(m, ",shortname=win95");
805 break;
806 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
807 seq_puts(m, ",shortname=winnt");
808 break;
809 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
810 seq_puts(m, ",shortname=mixed");
811 break;
812 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
813 /* seq_puts(m, ",shortname=lower"); */
814 break;
815 default:
816 seq_puts(m, ",shortname=unknown");
817 break;
820 if (opts->name_check != 'n')
821 seq_printf(m, ",check=%c", opts->name_check);
822 if (opts->usefree)
823 seq_puts(m, ",usefree");
824 if (opts->quiet)
825 seq_puts(m, ",quiet");
826 if (opts->showexec)
827 seq_puts(m, ",showexec");
828 if (opts->sys_immutable)
829 seq_puts(m, ",sys_immutable");
830 if (!isvfat) {
831 if (opts->dotsOK)
832 seq_puts(m, ",dotsOK=yes");
833 if (opts->nocase)
834 seq_puts(m, ",nocase");
835 } else {
836 if (opts->utf8)
837 seq_puts(m, ",utf8");
838 if (opts->unicode_xlate)
839 seq_puts(m, ",uni_xlate");
840 if (!opts->numtail)
841 seq_puts(m, ",nonumtail");
843 if (sbi->options.flush)
844 seq_puts(m, ",flush");
845 if (opts->tz_utc)
846 seq_puts(m, ",tz=UTC");
848 return 0;
851 enum {
852 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
853 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
854 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
855 Opt_immutable, Opt_dots, Opt_nodots,
856 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
857 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
858 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
859 Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_err,
862 static match_table_t fat_tokens = {
863 {Opt_check_r, "check=relaxed"},
864 {Opt_check_s, "check=strict"},
865 {Opt_check_n, "check=normal"},
866 {Opt_check_r, "check=r"},
867 {Opt_check_s, "check=s"},
868 {Opt_check_n, "check=n"},
869 {Opt_uid, "uid=%u"},
870 {Opt_gid, "gid=%u"},
871 {Opt_umask, "umask=%o"},
872 {Opt_dmask, "dmask=%o"},
873 {Opt_fmask, "fmask=%o"},
874 {Opt_allow_utime, "allow_utime=%o"},
875 {Opt_codepage, "codepage=%u"},
876 {Opt_usefree, "usefree"},
877 {Opt_nocase, "nocase"},
878 {Opt_quiet, "quiet"},
879 {Opt_showexec, "showexec"},
880 {Opt_debug, "debug"},
881 {Opt_immutable, "sys_immutable"},
882 {Opt_obsolate, "conv=binary"},
883 {Opt_obsolate, "conv=text"},
884 {Opt_obsolate, "conv=auto"},
885 {Opt_obsolate, "conv=b"},
886 {Opt_obsolate, "conv=t"},
887 {Opt_obsolate, "conv=a"},
888 {Opt_obsolate, "fat=%u"},
889 {Opt_obsolate, "blocksize=%u"},
890 {Opt_obsolate, "cvf_format=%20s"},
891 {Opt_obsolate, "cvf_options=%100s"},
892 {Opt_obsolate, "posix"},
893 {Opt_flush, "flush"},
894 {Opt_tz_utc, "tz=UTC"},
895 {Opt_err, NULL},
897 static match_table_t msdos_tokens = {
898 {Opt_nodots, "nodots"},
899 {Opt_nodots, "dotsOK=no"},
900 {Opt_dots, "dots"},
901 {Opt_dots, "dotsOK=yes"},
902 {Opt_err, NULL}
904 static match_table_t vfat_tokens = {
905 {Opt_charset, "iocharset=%s"},
906 {Opt_shortname_lower, "shortname=lower"},
907 {Opt_shortname_win95, "shortname=win95"},
908 {Opt_shortname_winnt, "shortname=winnt"},
909 {Opt_shortname_mixed, "shortname=mixed"},
910 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
911 {Opt_utf8_no, "utf8=no"},
912 {Opt_utf8_no, "utf8=false"},
913 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
914 {Opt_utf8_yes, "utf8=yes"},
915 {Opt_utf8_yes, "utf8=true"},
916 {Opt_utf8_yes, "utf8"},
917 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
918 {Opt_uni_xl_no, "uni_xlate=no"},
919 {Opt_uni_xl_no, "uni_xlate=false"},
920 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
921 {Opt_uni_xl_yes, "uni_xlate=yes"},
922 {Opt_uni_xl_yes, "uni_xlate=true"},
923 {Opt_uni_xl_yes, "uni_xlate"},
924 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
925 {Opt_nonumtail_no, "nonumtail=no"},
926 {Opt_nonumtail_no, "nonumtail=false"},
927 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
928 {Opt_nonumtail_yes, "nonumtail=yes"},
929 {Opt_nonumtail_yes, "nonumtail=true"},
930 {Opt_nonumtail_yes, "nonumtail"},
931 {Opt_err, NULL}
934 static int parse_options(char *options, int is_vfat, int silent, int *debug,
935 struct fat_mount_options *opts)
937 char *p;
938 substring_t args[MAX_OPT_ARGS];
939 int option;
940 char *iocharset;
942 opts->isvfat = is_vfat;
944 opts->fs_uid = current->uid;
945 opts->fs_gid = current->gid;
946 opts->fs_fmask = opts->fs_dmask = current->fs->umask;
947 opts->allow_utime = -1;
948 opts->codepage = fat_default_codepage;
949 opts->iocharset = fat_default_iocharset;
950 if (is_vfat)
951 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95;
952 else
953 opts->shortname = 0;
954 opts->name_check = 'n';
955 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
956 opts->utf8 = opts->unicode_xlate = 0;
957 opts->numtail = 1;
958 opts->usefree = opts->nocase = 0;
959 opts->tz_utc = 0;
960 *debug = 0;
962 if (!options)
963 goto out;
965 while ((p = strsep(&options, ",")) != NULL) {
966 int token;
967 if (!*p)
968 continue;
970 token = match_token(p, fat_tokens, args);
971 if (token == Opt_err) {
972 if (is_vfat)
973 token = match_token(p, vfat_tokens, args);
974 else
975 token = match_token(p, msdos_tokens, args);
977 switch (token) {
978 case Opt_check_s:
979 opts->name_check = 's';
980 break;
981 case Opt_check_r:
982 opts->name_check = 'r';
983 break;
984 case Opt_check_n:
985 opts->name_check = 'n';
986 break;
987 case Opt_usefree:
988 opts->usefree = 1;
989 break;
990 case Opt_nocase:
991 if (!is_vfat)
992 opts->nocase = 1;
993 else {
994 /* for backward compatibility */
995 opts->shortname = VFAT_SFN_DISPLAY_WIN95
996 | VFAT_SFN_CREATE_WIN95;
998 break;
999 case Opt_quiet:
1000 opts->quiet = 1;
1001 break;
1002 case Opt_showexec:
1003 opts->showexec = 1;
1004 break;
1005 case Opt_debug:
1006 *debug = 1;
1007 break;
1008 case Opt_immutable:
1009 opts->sys_immutable = 1;
1010 break;
1011 case Opt_uid:
1012 if (match_int(&args[0], &option))
1013 return 0;
1014 opts->fs_uid = option;
1015 break;
1016 case Opt_gid:
1017 if (match_int(&args[0], &option))
1018 return 0;
1019 opts->fs_gid = option;
1020 break;
1021 case Opt_umask:
1022 if (match_octal(&args[0], &option))
1023 return 0;
1024 opts->fs_fmask = opts->fs_dmask = option;
1025 break;
1026 case Opt_dmask:
1027 if (match_octal(&args[0], &option))
1028 return 0;
1029 opts->fs_dmask = option;
1030 break;
1031 case Opt_fmask:
1032 if (match_octal(&args[0], &option))
1033 return 0;
1034 opts->fs_fmask = option;
1035 break;
1036 case Opt_allow_utime:
1037 if (match_octal(&args[0], &option))
1038 return 0;
1039 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1040 break;
1041 case Opt_codepage:
1042 if (match_int(&args[0], &option))
1043 return 0;
1044 opts->codepage = option;
1045 break;
1046 case Opt_flush:
1047 opts->flush = 1;
1048 break;
1049 case Opt_tz_utc:
1050 opts->tz_utc = 1;
1051 break;
1053 /* msdos specific */
1054 case Opt_dots:
1055 opts->dotsOK = 1;
1056 break;
1057 case Opt_nodots:
1058 opts->dotsOK = 0;
1059 break;
1061 /* vfat specific */
1062 case Opt_charset:
1063 if (opts->iocharset != fat_default_iocharset)
1064 kfree(opts->iocharset);
1065 iocharset = match_strdup(&args[0]);
1066 if (!iocharset)
1067 return -ENOMEM;
1068 opts->iocharset = iocharset;
1069 break;
1070 case Opt_shortname_lower:
1071 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1072 | VFAT_SFN_CREATE_WIN95;
1073 break;
1074 case Opt_shortname_win95:
1075 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1076 | VFAT_SFN_CREATE_WIN95;
1077 break;
1078 case Opt_shortname_winnt:
1079 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1080 | VFAT_SFN_CREATE_WINNT;
1081 break;
1082 case Opt_shortname_mixed:
1083 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1084 | VFAT_SFN_CREATE_WIN95;
1085 break;
1086 case Opt_utf8_no: /* 0 or no or false */
1087 opts->utf8 = 0;
1088 break;
1089 case Opt_utf8_yes: /* empty or 1 or yes or true */
1090 opts->utf8 = 1;
1091 break;
1092 case Opt_uni_xl_no: /* 0 or no or false */
1093 opts->unicode_xlate = 0;
1094 break;
1095 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1096 opts->unicode_xlate = 1;
1097 break;
1098 case Opt_nonumtail_no: /* 0 or no or false */
1099 opts->numtail = 1; /* negated option */
1100 break;
1101 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1102 opts->numtail = 0; /* negated option */
1103 break;
1105 /* obsolete mount options */
1106 case Opt_obsolate:
1107 printk(KERN_INFO "FAT: \"%s\" option is obsolete, "
1108 "not supported now\n", p);
1109 break;
1110 /* unknown option */
1111 default:
1112 if (!silent) {
1113 printk(KERN_ERR
1114 "FAT: Unrecognized mount option \"%s\" "
1115 "or missing value\n", p);
1117 return -EINVAL;
1121 out:
1122 /* UTF-8 doesn't provide FAT semantics */
1123 if (!strcmp(opts->iocharset, "utf8")) {
1124 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset"
1125 " for FAT filesystems, filesystem will be "
1126 "case sensitive!\n");
1129 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1130 if (opts->allow_utime == (unsigned short)-1)
1131 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1132 if (opts->unicode_xlate)
1133 opts->utf8 = 0;
1135 return 0;
1138 static int fat_read_root(struct inode *inode)
1140 struct super_block *sb = inode->i_sb;
1141 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1142 int error;
1144 MSDOS_I(inode)->i_pos = 0;
1145 inode->i_uid = sbi->options.fs_uid;
1146 inode->i_gid = sbi->options.fs_gid;
1147 inode->i_version++;
1148 inode->i_generation = 0;
1149 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR;
1150 inode->i_op = sbi->dir_ops;
1151 inode->i_fop = &fat_dir_operations;
1152 if (sbi->fat_bits == 32) {
1153 MSDOS_I(inode)->i_start = sbi->root_cluster;
1154 error = fat_calc_dir_size(inode);
1155 if (error < 0)
1156 return error;
1157 } else {
1158 MSDOS_I(inode)->i_start = 0;
1159 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1161 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1162 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1163 MSDOS_I(inode)->i_logstart = 0;
1164 MSDOS_I(inode)->mmu_private = inode->i_size;
1166 MSDOS_I(inode)->i_attrs = ATTR_NONE;
1167 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1168 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1169 inode->i_nlink = fat_subdirs(inode)+2;
1171 return 0;
1175 * Read the super block of an MS-DOS FS.
1177 int fat_fill_super(struct super_block *sb, void *data, int silent,
1178 const struct inode_operations *fs_dir_inode_ops, int isvfat)
1180 struct inode *root_inode = NULL;
1181 struct buffer_head *bh;
1182 struct fat_boot_sector *b;
1183 struct msdos_sb_info *sbi;
1184 u16 logical_sector_size;
1185 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1186 int debug;
1187 unsigned int media;
1188 long error;
1189 char buf[50];
1192 * GFP_KERNEL is ok here, because while we do hold the
1193 * supeblock lock, memory pressure can't call back into
1194 * the filesystem, since we're only just about to mount
1195 * it and have no inodes etc active!
1197 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1198 if (!sbi)
1199 return -ENOMEM;
1200 sb->s_fs_info = sbi;
1202 sb->s_flags |= MS_NODIRATIME;
1203 sb->s_magic = MSDOS_SUPER_MAGIC;
1204 sb->s_op = &fat_sops;
1205 sb->s_export_op = &fat_export_ops;
1206 sbi->dir_ops = fs_dir_inode_ops;
1208 error = parse_options(data, isvfat, silent, &debug, &sbi->options);
1209 if (error)
1210 goto out_fail;
1212 error = -EIO;
1213 sb_min_blocksize(sb, 512);
1214 bh = sb_bread(sb, 0);
1215 if (bh == NULL) {
1216 printk(KERN_ERR "FAT: unable to read boot sector\n");
1217 goto out_fail;
1220 b = (struct fat_boot_sector *) bh->b_data;
1221 if (!b->reserved) {
1222 if (!silent)
1223 printk(KERN_ERR "FAT: bogus number of reserved sectors\n");
1224 brelse(bh);
1225 goto out_invalid;
1227 if (!b->fats) {
1228 if (!silent)
1229 printk(KERN_ERR "FAT: bogus number of FAT structure\n");
1230 brelse(bh);
1231 goto out_invalid;
1235 * Earlier we checked here that b->secs_track and b->head are nonzero,
1236 * but it turns out valid FAT filesystems can have zero there.
1239 media = b->media;
1240 if (!fat_valid_media(media)) {
1241 if (!silent)
1242 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n",
1243 media);
1244 brelse(bh);
1245 goto out_invalid;
1247 logical_sector_size = get_unaligned_le16(&b->sector_size);
1248 if (!is_power_of_2(logical_sector_size)
1249 || (logical_sector_size < 512)
1250 || (logical_sector_size > 4096)) {
1251 if (!silent)
1252 printk(KERN_ERR "FAT: bogus logical sector size %u\n",
1253 logical_sector_size);
1254 brelse(bh);
1255 goto out_invalid;
1257 sbi->sec_per_clus = b->sec_per_clus;
1258 if (!is_power_of_2(sbi->sec_per_clus)) {
1259 if (!silent)
1260 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
1261 sbi->sec_per_clus);
1262 brelse(bh);
1263 goto out_invalid;
1266 if (logical_sector_size < sb->s_blocksize) {
1267 printk(KERN_ERR "FAT: logical sector size too small for device"
1268 " (logical sector size = %u)\n", logical_sector_size);
1269 brelse(bh);
1270 goto out_fail;
1272 if (logical_sector_size > sb->s_blocksize) {
1273 brelse(bh);
1275 if (!sb_set_blocksize(sb, logical_sector_size)) {
1276 printk(KERN_ERR "FAT: unable to set blocksize %u\n",
1277 logical_sector_size);
1278 goto out_fail;
1280 bh = sb_bread(sb, 0);
1281 if (bh == NULL) {
1282 printk(KERN_ERR "FAT: unable to read boot sector"
1283 " (logical sector size = %lu)\n",
1284 sb->s_blocksize);
1285 goto out_fail;
1287 b = (struct fat_boot_sector *) bh->b_data;
1290 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1291 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1292 sbi->fats = b->fats;
1293 sbi->fat_bits = 0; /* Don't know yet */
1294 sbi->fat_start = le16_to_cpu(b->reserved);
1295 sbi->fat_length = le16_to_cpu(b->fat_length);
1296 sbi->root_cluster = 0;
1297 sbi->free_clusters = -1; /* Don't know yet */
1298 sbi->free_clus_valid = 0;
1299 sbi->prev_free = FAT_START_ENT;
1301 if (!sbi->fat_length && b->fat32_length) {
1302 struct fat_boot_fsinfo *fsinfo;
1303 struct buffer_head *fsinfo_bh;
1305 /* Must be FAT32 */
1306 sbi->fat_bits = 32;
1307 sbi->fat_length = le32_to_cpu(b->fat32_length);
1308 sbi->root_cluster = le32_to_cpu(b->root_cluster);
1310 sb->s_maxbytes = 0xffffffff;
1312 /* MC - if info_sector is 0, don't multiply by 0 */
1313 sbi->fsinfo_sector = le16_to_cpu(b->info_sector);
1314 if (sbi->fsinfo_sector == 0)
1315 sbi->fsinfo_sector = 1;
1317 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1318 if (fsinfo_bh == NULL) {
1319 printk(KERN_ERR "FAT: bread failed, FSINFO block"
1320 " (sector = %lu)\n", sbi->fsinfo_sector);
1321 brelse(bh);
1322 goto out_fail;
1325 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1326 if (!IS_FSINFO(fsinfo)) {
1327 printk(KERN_WARNING "FAT: Invalid FSINFO signature: "
1328 "0x%08x, 0x%08x (sector = %lu)\n",
1329 le32_to_cpu(fsinfo->signature1),
1330 le32_to_cpu(fsinfo->signature2),
1331 sbi->fsinfo_sector);
1332 } else {
1333 if (sbi->options.usefree)
1334 sbi->free_clus_valid = 1;
1335 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1336 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1339 brelse(fsinfo_bh);
1342 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1343 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1345 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1346 sbi->dir_entries = get_unaligned_le16(&b->dir_entries);
1347 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1348 if (!silent)
1349 printk(KERN_ERR "FAT: bogus directroy-entries per block"
1350 " (%u)\n", sbi->dir_entries);
1351 brelse(bh);
1352 goto out_invalid;
1355 rootdir_sectors = sbi->dir_entries
1356 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1357 sbi->data_start = sbi->dir_start + rootdir_sectors;
1358 total_sectors = get_unaligned_le16(&b->sectors);
1359 if (total_sectors == 0)
1360 total_sectors = le32_to_cpu(b->total_sect);
1362 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1364 if (sbi->fat_bits != 32)
1365 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1367 /* check that FAT table does not overflow */
1368 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1369 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1370 if (total_clusters > MAX_FAT(sb)) {
1371 if (!silent)
1372 printk(KERN_ERR "FAT: count of clusters too big (%u)\n",
1373 total_clusters);
1374 brelse(bh);
1375 goto out_invalid;
1378 sbi->max_cluster = total_clusters + FAT_START_ENT;
1379 /* check the free_clusters, it's not necessarily correct */
1380 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1381 sbi->free_clusters = -1;
1382 /* check the prev_free, it's not necessarily correct */
1383 sbi->prev_free %= sbi->max_cluster;
1384 if (sbi->prev_free < FAT_START_ENT)
1385 sbi->prev_free = FAT_START_ENT;
1387 brelse(bh);
1389 /* set up enough so that it can read an inode */
1390 fat_hash_init(sb);
1391 fat_ent_access_init(sb);
1394 * The low byte of FAT's first entry must have same value with
1395 * media-field. But in real world, too many devices is
1396 * writing wrong value. So, removed that validity check.
1398 * if (FAT_FIRST_ENT(sb, media) != first)
1401 error = -EINVAL;
1402 sprintf(buf, "cp%d", sbi->options.codepage);
1403 sbi->nls_disk = load_nls(buf);
1404 if (!sbi->nls_disk) {
1405 printk(KERN_ERR "FAT: codepage %s not found\n", buf);
1406 goto out_fail;
1409 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1410 if (sbi->options.isvfat) {
1411 sbi->nls_io = load_nls(sbi->options.iocharset);
1412 if (!sbi->nls_io) {
1413 printk(KERN_ERR "FAT: IO charset %s not found\n",
1414 sbi->options.iocharset);
1415 goto out_fail;
1419 error = -ENOMEM;
1420 root_inode = new_inode(sb);
1421 if (!root_inode)
1422 goto out_fail;
1423 root_inode->i_ino = MSDOS_ROOT_INO;
1424 root_inode->i_version = 1;
1425 error = fat_read_root(root_inode);
1426 if (error < 0)
1427 goto out_fail;
1428 error = -ENOMEM;
1429 insert_inode_hash(root_inode);
1430 sb->s_root = d_alloc_root(root_inode);
1431 if (!sb->s_root) {
1432 printk(KERN_ERR "FAT: get root inode failed\n");
1433 goto out_fail;
1436 return 0;
1438 out_invalid:
1439 error = -EINVAL;
1440 if (!silent)
1441 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem"
1442 " on dev %s.\n", sb->s_id);
1444 out_fail:
1445 if (root_inode)
1446 iput(root_inode);
1447 if (sbi->nls_io)
1448 unload_nls(sbi->nls_io);
1449 if (sbi->nls_disk)
1450 unload_nls(sbi->nls_disk);
1451 if (sbi->options.iocharset != fat_default_iocharset)
1452 kfree(sbi->options.iocharset);
1453 sb->s_fs_info = NULL;
1454 kfree(sbi);
1455 return error;
1458 EXPORT_SYMBOL_GPL(fat_fill_super);
1461 * helper function for fat_flush_inodes. This writes both the inode
1462 * and the file data blocks, waiting for in flight data blocks before
1463 * the start of the call. It does not wait for any io started
1464 * during the call
1466 static int writeback_inode(struct inode *inode)
1469 int ret;
1470 struct address_space *mapping = inode->i_mapping;
1471 struct writeback_control wbc = {
1472 .sync_mode = WB_SYNC_NONE,
1473 .nr_to_write = 0,
1475 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the
1476 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode
1477 * and filemap_fdatawrite is used for the data blocks
1479 ret = sync_inode(inode, &wbc);
1480 if (!ret)
1481 ret = filemap_fdatawrite(mapping);
1482 return ret;
1486 * write data and metadata corresponding to i1 and i2. The io is
1487 * started but we do not wait for any of it to finish.
1489 * filemap_flush is used for the block device, so if there is a dirty
1490 * page for a block already in flight, we will not wait and start the
1491 * io over again
1493 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1495 int ret = 0;
1496 if (!MSDOS_SB(sb)->options.flush)
1497 return 0;
1498 if (i1)
1499 ret = writeback_inode(i1);
1500 if (!ret && i2)
1501 ret = writeback_inode(i2);
1502 if (!ret) {
1503 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1504 ret = filemap_flush(mapping);
1506 return ret;
1508 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1510 static int __init init_fat_fs(void)
1512 int err;
1514 err = fat_cache_init();
1515 if (err)
1516 return err;
1518 err = fat_init_inodecache();
1519 if (err)
1520 goto failed;
1522 return 0;
1524 failed:
1525 fat_cache_destroy();
1526 return err;
1529 static void __exit exit_fat_fs(void)
1531 fat_cache_destroy();
1532 fat_destroy_inodecache();
1535 module_init(init_fat_fs)
1536 module_exit(exit_fat_fs)
1538 MODULE_LICENSE("GPL");