ipv4: Do cleanup for ip_mr_init
[linux-2.6/mini2440.git] / fs / fat / inode.c
blob4e0a3dd9d6779a1d9101704d470b1263b194d7d5
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 inode->i_mtime.tv_nsec = 0;
387 if (sbi->options.isvfat) {
388 int secs = de->ctime_cs / 100;
389 int csecs = de->ctime_cs % 100;
390 inode->i_ctime.tv_sec =
391 date_dos2unix(le16_to_cpu(de->ctime),
392 le16_to_cpu(de->cdate)) + secs;
393 inode->i_ctime.tv_nsec = csecs * 10000000;
394 inode->i_atime.tv_sec =
395 date_dos2unix(0, le16_to_cpu(de->adate));
396 inode->i_atime.tv_nsec = 0;
397 } else
398 inode->i_ctime = inode->i_atime = inode->i_mtime;
400 return 0;
403 struct inode *fat_build_inode(struct super_block *sb,
404 struct msdos_dir_entry *de, loff_t i_pos)
406 struct inode *inode;
407 int err;
409 inode = fat_iget(sb, i_pos);
410 if (inode)
411 goto out;
412 inode = new_inode(sb);
413 if (!inode) {
414 inode = ERR_PTR(-ENOMEM);
415 goto out;
417 inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
418 inode->i_version = 1;
419 err = fat_fill_inode(inode, de);
420 if (err) {
421 iput(inode);
422 inode = ERR_PTR(err);
423 goto out;
425 fat_attach(inode, i_pos);
426 insert_inode_hash(inode);
427 out:
428 return inode;
431 EXPORT_SYMBOL_GPL(fat_build_inode);
433 static void fat_delete_inode(struct inode *inode)
435 truncate_inode_pages(&inode->i_data, 0);
436 inode->i_size = 0;
437 fat_truncate(inode);
438 clear_inode(inode);
441 static void fat_clear_inode(struct inode *inode)
443 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
445 lock_kernel();
446 spin_lock(&sbi->inode_hash_lock);
447 fat_cache_inval_inode(inode);
448 hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
449 spin_unlock(&sbi->inode_hash_lock);
450 unlock_kernel();
453 static void fat_write_super(struct super_block *sb)
455 sb->s_dirt = 0;
457 if (!(sb->s_flags & MS_RDONLY))
458 fat_clusters_flush(sb);
461 static void fat_put_super(struct super_block *sb)
463 struct msdos_sb_info *sbi = MSDOS_SB(sb);
465 if (sbi->nls_disk) {
466 unload_nls(sbi->nls_disk);
467 sbi->nls_disk = NULL;
468 sbi->options.codepage = fat_default_codepage;
470 if (sbi->nls_io) {
471 unload_nls(sbi->nls_io);
472 sbi->nls_io = NULL;
474 if (sbi->options.iocharset != fat_default_iocharset) {
475 kfree(sbi->options.iocharset);
476 sbi->options.iocharset = fat_default_iocharset;
479 sb->s_fs_info = NULL;
480 kfree(sbi);
483 static struct kmem_cache *fat_inode_cachep;
485 static struct inode *fat_alloc_inode(struct super_block *sb)
487 struct msdos_inode_info *ei;
488 ei = kmem_cache_alloc(fat_inode_cachep, GFP_KERNEL);
489 if (!ei)
490 return NULL;
491 return &ei->vfs_inode;
494 static void fat_destroy_inode(struct inode *inode)
496 kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
499 static void init_once(struct kmem_cache *cachep, void *foo)
501 struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
503 spin_lock_init(&ei->cache_lru_lock);
504 ei->nr_caches = 0;
505 ei->cache_valid_id = FAT_CACHE_VALID + 1;
506 INIT_LIST_HEAD(&ei->cache_lru);
507 INIT_HLIST_NODE(&ei->i_fat_hash);
508 inode_init_once(&ei->vfs_inode);
511 static int __init fat_init_inodecache(void)
513 fat_inode_cachep = kmem_cache_create("fat_inode_cache",
514 sizeof(struct msdos_inode_info),
515 0, (SLAB_RECLAIM_ACCOUNT|
516 SLAB_MEM_SPREAD),
517 init_once);
518 if (fat_inode_cachep == NULL)
519 return -ENOMEM;
520 return 0;
523 static void __exit fat_destroy_inodecache(void)
525 kmem_cache_destroy(fat_inode_cachep);
528 static int fat_remount(struct super_block *sb, int *flags, char *data)
530 struct msdos_sb_info *sbi = MSDOS_SB(sb);
531 *flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
532 return 0;
535 static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
537 struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
539 /* If the count of free cluster is still unknown, counts it here. */
540 if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
541 int err = fat_count_free_clusters(dentry->d_sb);
542 if (err)
543 return err;
546 buf->f_type = dentry->d_sb->s_magic;
547 buf->f_bsize = sbi->cluster_size;
548 buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
549 buf->f_bfree = sbi->free_clusters;
550 buf->f_bavail = sbi->free_clusters;
551 buf->f_namelen = sbi->options.isvfat ? 260 : 12;
553 return 0;
556 static int fat_write_inode(struct inode *inode, int wait)
558 struct super_block *sb = inode->i_sb;
559 struct msdos_sb_info *sbi = MSDOS_SB(sb);
560 struct buffer_head *bh;
561 struct msdos_dir_entry *raw_entry;
562 loff_t i_pos;
563 int err = 0;
565 retry:
566 i_pos = MSDOS_I(inode)->i_pos;
567 if (inode->i_ino == MSDOS_ROOT_INO || !i_pos)
568 return 0;
570 lock_kernel();
571 bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
572 if (!bh) {
573 printk(KERN_ERR "FAT: unable to read inode block "
574 "for updating (i_pos %lld)\n", i_pos);
575 err = -EIO;
576 goto out;
578 spin_lock(&sbi->inode_hash_lock);
579 if (i_pos != MSDOS_I(inode)->i_pos) {
580 spin_unlock(&sbi->inode_hash_lock);
581 brelse(bh);
582 unlock_kernel();
583 goto retry;
586 raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
587 [i_pos & (sbi->dir_per_block - 1)];
588 if (S_ISDIR(inode->i_mode))
589 raw_entry->size = 0;
590 else
591 raw_entry->size = cpu_to_le32(inode->i_size);
592 raw_entry->attr = fat_attr(inode);
593 raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
594 raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
595 fat_date_unix2dos(inode->i_mtime.tv_sec, &raw_entry->time, &raw_entry->date);
596 if (sbi->options.isvfat) {
597 __le16 atime;
598 fat_date_unix2dos(inode->i_ctime.tv_sec,&raw_entry->ctime,&raw_entry->cdate);
599 fat_date_unix2dos(inode->i_atime.tv_sec,&atime,&raw_entry->adate);
600 raw_entry->ctime_cs = (inode->i_ctime.tv_sec & 1) * 100 +
601 inode->i_ctime.tv_nsec / 10000000;
603 spin_unlock(&sbi->inode_hash_lock);
604 mark_buffer_dirty(bh);
605 if (wait)
606 err = sync_dirty_buffer(bh);
607 brelse(bh);
608 out:
609 unlock_kernel();
610 return err;
613 int fat_sync_inode(struct inode *inode)
615 return fat_write_inode(inode, 1);
618 EXPORT_SYMBOL_GPL(fat_sync_inode);
620 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt);
621 static const struct super_operations fat_sops = {
622 .alloc_inode = fat_alloc_inode,
623 .destroy_inode = fat_destroy_inode,
624 .write_inode = fat_write_inode,
625 .delete_inode = fat_delete_inode,
626 .put_super = fat_put_super,
627 .write_super = fat_write_super,
628 .statfs = fat_statfs,
629 .clear_inode = fat_clear_inode,
630 .remount_fs = fat_remount,
632 .show_options = fat_show_options,
636 * a FAT file handle with fhtype 3 is
637 * 0/ i_ino - for fast, reliable lookup if still in the cache
638 * 1/ i_generation - to see if i_ino is still valid
639 * bit 0 == 0 iff directory
640 * 2/ i_pos(8-39) - if ino has changed, but still in cache
641 * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
642 * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
644 * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
645 * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
646 * of i_logstart is used to store the directory entry offset.
649 static struct dentry *fat_fh_to_dentry(struct super_block *sb,
650 struct fid *fid, int fh_len, int fh_type)
652 struct inode *inode = NULL;
653 struct dentry *result;
654 u32 *fh = fid->raw;
656 if (fh_len < 5 || fh_type != 3)
657 return NULL;
659 inode = ilookup(sb, fh[0]);
660 if (!inode || inode->i_generation != fh[1]) {
661 if (inode)
662 iput(inode);
663 inode = NULL;
665 if (!inode) {
666 loff_t i_pos;
667 int i_logstart = fh[3] & 0x0fffffff;
669 i_pos = (loff_t)fh[2] << 8;
670 i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);
672 /* try 2 - see if i_pos is in F-d-c
673 * require i_logstart to be the same
674 * Will fail if you truncate and then re-write
677 inode = fat_iget(sb, i_pos);
678 if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
679 iput(inode);
680 inode = NULL;
683 if (!inode) {
684 /* For now, do nothing
685 * What we could do is:
686 * follow the file starting at fh[4], and record
687 * the ".." entry, and the name of the fh[2] entry.
688 * The follow the ".." file finding the next step up.
689 * This way we build a path to the root of
690 * the tree. If this works, we lookup the path and so
691 * get this inode into the cache.
692 * Finally try the fat_iget lookup again
693 * If that fails, then weare totally out of luck
694 * But all that is for another day
697 if (!inode)
698 return ERR_PTR(-ESTALE);
701 /* now to find a dentry.
702 * If possible, get a well-connected one
704 result = d_alloc_anon(inode);
705 if (result == NULL) {
706 iput(inode);
707 return ERR_PTR(-ENOMEM);
709 result->d_op = sb->s_root->d_op;
710 return result;
713 static int
714 fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
716 int len = *lenp;
717 struct inode *inode = de->d_inode;
718 u32 ipos_h, ipos_m, ipos_l;
720 if (len < 5)
721 return 255; /* no room */
723 ipos_h = MSDOS_I(inode)->i_pos >> 8;
724 ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
725 ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28;
726 *lenp = 5;
727 fh[0] = inode->i_ino;
728 fh[1] = inode->i_generation;
729 fh[2] = ipos_h;
730 fh[3] = ipos_m | MSDOS_I(inode)->i_logstart;
731 spin_lock(&de->d_lock);
732 fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart;
733 spin_unlock(&de->d_lock);
734 return 3;
737 static struct dentry *fat_get_parent(struct dentry *child)
739 struct buffer_head *bh;
740 struct msdos_dir_entry *de;
741 loff_t i_pos;
742 struct dentry *parent;
743 struct inode *inode;
744 int err;
746 lock_kernel();
748 err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos);
749 if (err) {
750 parent = ERR_PTR(err);
751 goto out;
753 inode = fat_build_inode(child->d_sb, de, i_pos);
754 brelse(bh);
755 if (IS_ERR(inode)) {
756 parent = ERR_CAST(inode);
757 goto out;
759 parent = d_alloc_anon(inode);
760 if (!parent) {
761 iput(inode);
762 parent = ERR_PTR(-ENOMEM);
764 out:
765 unlock_kernel();
767 return parent;
770 static const struct export_operations fat_export_ops = {
771 .encode_fh = fat_encode_fh,
772 .fh_to_dentry = fat_fh_to_dentry,
773 .get_parent = fat_get_parent,
776 static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
778 struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb);
779 struct fat_mount_options *opts = &sbi->options;
780 int isvfat = opts->isvfat;
782 if (opts->fs_uid != 0)
783 seq_printf(m, ",uid=%u", opts->fs_uid);
784 if (opts->fs_gid != 0)
785 seq_printf(m, ",gid=%u", opts->fs_gid);
786 seq_printf(m, ",fmask=%04o", opts->fs_fmask);
787 seq_printf(m, ",dmask=%04o", opts->fs_dmask);
788 if (opts->allow_utime)
789 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
790 if (sbi->nls_disk)
791 seq_printf(m, ",codepage=%s", sbi->nls_disk->charset);
792 if (isvfat) {
793 if (sbi->nls_io)
794 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
796 switch (opts->shortname) {
797 case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
798 seq_puts(m, ",shortname=win95");
799 break;
800 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
801 seq_puts(m, ",shortname=winnt");
802 break;
803 case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
804 seq_puts(m, ",shortname=mixed");
805 break;
806 case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
807 /* seq_puts(m, ",shortname=lower"); */
808 break;
809 default:
810 seq_puts(m, ",shortname=unknown");
811 break;
814 if (opts->name_check != 'n')
815 seq_printf(m, ",check=%c", opts->name_check);
816 if (opts->usefree)
817 seq_puts(m, ",usefree");
818 if (opts->quiet)
819 seq_puts(m, ",quiet");
820 if (opts->showexec)
821 seq_puts(m, ",showexec");
822 if (opts->sys_immutable)
823 seq_puts(m, ",sys_immutable");
824 if (!isvfat) {
825 if (opts->dotsOK)
826 seq_puts(m, ",dotsOK=yes");
827 if (opts->nocase)
828 seq_puts(m, ",nocase");
829 } else {
830 if (opts->utf8)
831 seq_puts(m, ",utf8");
832 if (opts->unicode_xlate)
833 seq_puts(m, ",uni_xlate");
834 if (!opts->numtail)
835 seq_puts(m, ",nonumtail");
837 if (sbi->options.flush)
838 seq_puts(m, ",flush");
840 return 0;
843 enum {
844 Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
845 Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
846 Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
847 Opt_immutable, Opt_dots, Opt_nodots,
848 Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
849 Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
850 Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
851 Opt_obsolate, Opt_flush, Opt_err,
854 static match_table_t fat_tokens = {
855 {Opt_check_r, "check=relaxed"},
856 {Opt_check_s, "check=strict"},
857 {Opt_check_n, "check=normal"},
858 {Opt_check_r, "check=r"},
859 {Opt_check_s, "check=s"},
860 {Opt_check_n, "check=n"},
861 {Opt_uid, "uid=%u"},
862 {Opt_gid, "gid=%u"},
863 {Opt_umask, "umask=%o"},
864 {Opt_dmask, "dmask=%o"},
865 {Opt_fmask, "fmask=%o"},
866 {Opt_allow_utime, "allow_utime=%o"},
867 {Opt_codepage, "codepage=%u"},
868 {Opt_usefree, "usefree"},
869 {Opt_nocase, "nocase"},
870 {Opt_quiet, "quiet"},
871 {Opt_showexec, "showexec"},
872 {Opt_debug, "debug"},
873 {Opt_immutable, "sys_immutable"},
874 {Opt_obsolate, "conv=binary"},
875 {Opt_obsolate, "conv=text"},
876 {Opt_obsolate, "conv=auto"},
877 {Opt_obsolate, "conv=b"},
878 {Opt_obsolate, "conv=t"},
879 {Opt_obsolate, "conv=a"},
880 {Opt_obsolate, "fat=%u"},
881 {Opt_obsolate, "blocksize=%u"},
882 {Opt_obsolate, "cvf_format=%20s"},
883 {Opt_obsolate, "cvf_options=%100s"},
884 {Opt_obsolate, "posix"},
885 {Opt_flush, "flush"},
886 {Opt_err, NULL},
888 static match_table_t msdos_tokens = {
889 {Opt_nodots, "nodots"},
890 {Opt_nodots, "dotsOK=no"},
891 {Opt_dots, "dots"},
892 {Opt_dots, "dotsOK=yes"},
893 {Opt_err, NULL}
895 static match_table_t vfat_tokens = {
896 {Opt_charset, "iocharset=%s"},
897 {Opt_shortname_lower, "shortname=lower"},
898 {Opt_shortname_win95, "shortname=win95"},
899 {Opt_shortname_winnt, "shortname=winnt"},
900 {Opt_shortname_mixed, "shortname=mixed"},
901 {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */
902 {Opt_utf8_no, "utf8=no"},
903 {Opt_utf8_no, "utf8=false"},
904 {Opt_utf8_yes, "utf8=1"}, /* empty or 1 or yes or true */
905 {Opt_utf8_yes, "utf8=yes"},
906 {Opt_utf8_yes, "utf8=true"},
907 {Opt_utf8_yes, "utf8"},
908 {Opt_uni_xl_no, "uni_xlate=0"}, /* 0 or no or false */
909 {Opt_uni_xl_no, "uni_xlate=no"},
910 {Opt_uni_xl_no, "uni_xlate=false"},
911 {Opt_uni_xl_yes, "uni_xlate=1"}, /* empty or 1 or yes or true */
912 {Opt_uni_xl_yes, "uni_xlate=yes"},
913 {Opt_uni_xl_yes, "uni_xlate=true"},
914 {Opt_uni_xl_yes, "uni_xlate"},
915 {Opt_nonumtail_no, "nonumtail=0"}, /* 0 or no or false */
916 {Opt_nonumtail_no, "nonumtail=no"},
917 {Opt_nonumtail_no, "nonumtail=false"},
918 {Opt_nonumtail_yes, "nonumtail=1"}, /* empty or 1 or yes or true */
919 {Opt_nonumtail_yes, "nonumtail=yes"},
920 {Opt_nonumtail_yes, "nonumtail=true"},
921 {Opt_nonumtail_yes, "nonumtail"},
922 {Opt_err, NULL}
925 static int parse_options(char *options, int is_vfat, int silent, int *debug,
926 struct fat_mount_options *opts)
928 char *p;
929 substring_t args[MAX_OPT_ARGS];
930 int option;
931 char *iocharset;
933 opts->isvfat = is_vfat;
935 opts->fs_uid = current->uid;
936 opts->fs_gid = current->gid;
937 opts->fs_fmask = opts->fs_dmask = current->fs->umask;
938 opts->allow_utime = -1;
939 opts->codepage = fat_default_codepage;
940 opts->iocharset = fat_default_iocharset;
941 if (is_vfat)
942 opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95;
943 else
944 opts->shortname = 0;
945 opts->name_check = 'n';
946 opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
947 opts->utf8 = opts->unicode_xlate = 0;
948 opts->numtail = 1;
949 opts->usefree = opts->nocase = 0;
950 *debug = 0;
952 if (!options)
953 return 0;
955 while ((p = strsep(&options, ",")) != NULL) {
956 int token;
957 if (!*p)
958 continue;
960 token = match_token(p, fat_tokens, args);
961 if (token == Opt_err) {
962 if (is_vfat)
963 token = match_token(p, vfat_tokens, args);
964 else
965 token = match_token(p, msdos_tokens, args);
967 switch (token) {
968 case Opt_check_s:
969 opts->name_check = 's';
970 break;
971 case Opt_check_r:
972 opts->name_check = 'r';
973 break;
974 case Opt_check_n:
975 opts->name_check = 'n';
976 break;
977 case Opt_usefree:
978 opts->usefree = 1;
979 break;
980 case Opt_nocase:
981 if (!is_vfat)
982 opts->nocase = 1;
983 else {
984 /* for backward compatibility */
985 opts->shortname = VFAT_SFN_DISPLAY_WIN95
986 | VFAT_SFN_CREATE_WIN95;
988 break;
989 case Opt_quiet:
990 opts->quiet = 1;
991 break;
992 case Opt_showexec:
993 opts->showexec = 1;
994 break;
995 case Opt_debug:
996 *debug = 1;
997 break;
998 case Opt_immutable:
999 opts->sys_immutable = 1;
1000 break;
1001 case Opt_uid:
1002 if (match_int(&args[0], &option))
1003 return 0;
1004 opts->fs_uid = option;
1005 break;
1006 case Opt_gid:
1007 if (match_int(&args[0], &option))
1008 return 0;
1009 opts->fs_gid = option;
1010 break;
1011 case Opt_umask:
1012 if (match_octal(&args[0], &option))
1013 return 0;
1014 opts->fs_fmask = opts->fs_dmask = option;
1015 break;
1016 case Opt_dmask:
1017 if (match_octal(&args[0], &option))
1018 return 0;
1019 opts->fs_dmask = option;
1020 break;
1021 case Opt_fmask:
1022 if (match_octal(&args[0], &option))
1023 return 0;
1024 opts->fs_fmask = option;
1025 break;
1026 case Opt_allow_utime:
1027 if (match_octal(&args[0], &option))
1028 return 0;
1029 opts->allow_utime = option & (S_IWGRP | S_IWOTH);
1030 break;
1031 case Opt_codepage:
1032 if (match_int(&args[0], &option))
1033 return 0;
1034 opts->codepage = option;
1035 break;
1036 case Opt_flush:
1037 opts->flush = 1;
1038 break;
1040 /* msdos specific */
1041 case Opt_dots:
1042 opts->dotsOK = 1;
1043 break;
1044 case Opt_nodots:
1045 opts->dotsOK = 0;
1046 break;
1048 /* vfat specific */
1049 case Opt_charset:
1050 if (opts->iocharset != fat_default_iocharset)
1051 kfree(opts->iocharset);
1052 iocharset = match_strdup(&args[0]);
1053 if (!iocharset)
1054 return -ENOMEM;
1055 opts->iocharset = iocharset;
1056 break;
1057 case Opt_shortname_lower:
1058 opts->shortname = VFAT_SFN_DISPLAY_LOWER
1059 | VFAT_SFN_CREATE_WIN95;
1060 break;
1061 case Opt_shortname_win95:
1062 opts->shortname = VFAT_SFN_DISPLAY_WIN95
1063 | VFAT_SFN_CREATE_WIN95;
1064 break;
1065 case Opt_shortname_winnt:
1066 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1067 | VFAT_SFN_CREATE_WINNT;
1068 break;
1069 case Opt_shortname_mixed:
1070 opts->shortname = VFAT_SFN_DISPLAY_WINNT
1071 | VFAT_SFN_CREATE_WIN95;
1072 break;
1073 case Opt_utf8_no: /* 0 or no or false */
1074 opts->utf8 = 0;
1075 break;
1076 case Opt_utf8_yes: /* empty or 1 or yes or true */
1077 opts->utf8 = 1;
1078 break;
1079 case Opt_uni_xl_no: /* 0 or no or false */
1080 opts->unicode_xlate = 0;
1081 break;
1082 case Opt_uni_xl_yes: /* empty or 1 or yes or true */
1083 opts->unicode_xlate = 1;
1084 break;
1085 case Opt_nonumtail_no: /* 0 or no or false */
1086 opts->numtail = 1; /* negated option */
1087 break;
1088 case Opt_nonumtail_yes: /* empty or 1 or yes or true */
1089 opts->numtail = 0; /* negated option */
1090 break;
1092 /* obsolete mount options */
1093 case Opt_obsolate:
1094 printk(KERN_INFO "FAT: \"%s\" option is obsolete, "
1095 "not supported now\n", p);
1096 break;
1097 /* unknown option */
1098 default:
1099 if (!silent) {
1100 printk(KERN_ERR
1101 "FAT: Unrecognized mount option \"%s\" "
1102 "or missing value\n", p);
1104 return -EINVAL;
1107 /* UTF-8 doesn't provide FAT semantics */
1108 if (!strcmp(opts->iocharset, "utf8")) {
1109 printk(KERN_ERR "FAT: utf8 is not a recommended IO charset"
1110 " for FAT filesystems, filesystem will be case sensitive!\n");
1113 /* If user doesn't specify allow_utime, it's initialized from dmask. */
1114 if (opts->allow_utime == (unsigned short)-1)
1115 opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
1116 if (opts->unicode_xlate)
1117 opts->utf8 = 0;
1119 return 0;
1122 static int fat_read_root(struct inode *inode)
1124 struct super_block *sb = inode->i_sb;
1125 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1126 int error;
1128 MSDOS_I(inode)->i_pos = 0;
1129 inode->i_uid = sbi->options.fs_uid;
1130 inode->i_gid = sbi->options.fs_gid;
1131 inode->i_version++;
1132 inode->i_generation = 0;
1133 inode->i_mode = (S_IRWXUGO & ~sbi->options.fs_dmask) | S_IFDIR;
1134 inode->i_op = sbi->dir_ops;
1135 inode->i_fop = &fat_dir_operations;
1136 if (sbi->fat_bits == 32) {
1137 MSDOS_I(inode)->i_start = sbi->root_cluster;
1138 error = fat_calc_dir_size(inode);
1139 if (error < 0)
1140 return error;
1141 } else {
1142 MSDOS_I(inode)->i_start = 0;
1143 inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
1145 inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
1146 & ~((loff_t)sbi->cluster_size - 1)) >> 9;
1147 MSDOS_I(inode)->i_logstart = 0;
1148 MSDOS_I(inode)->mmu_private = inode->i_size;
1150 MSDOS_I(inode)->i_attrs = ATTR_NONE;
1151 inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
1152 inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1153 inode->i_nlink = fat_subdirs(inode)+2;
1155 return 0;
1159 * Read the super block of an MS-DOS FS.
1161 int fat_fill_super(struct super_block *sb, void *data, int silent,
1162 const struct inode_operations *fs_dir_inode_ops, int isvfat)
1164 struct inode *root_inode = NULL;
1165 struct buffer_head *bh;
1166 struct fat_boot_sector *b;
1167 struct msdos_sb_info *sbi;
1168 u16 logical_sector_size;
1169 u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
1170 int debug;
1171 unsigned int media;
1172 long error;
1173 char buf[50];
1175 sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
1176 if (!sbi)
1177 return -ENOMEM;
1178 sb->s_fs_info = sbi;
1180 sb->s_flags |= MS_NODIRATIME;
1181 sb->s_magic = MSDOS_SUPER_MAGIC;
1182 sb->s_op = &fat_sops;
1183 sb->s_export_op = &fat_export_ops;
1184 sbi->dir_ops = fs_dir_inode_ops;
1186 error = parse_options(data, isvfat, silent, &debug, &sbi->options);
1187 if (error)
1188 goto out_fail;
1190 error = -EIO;
1191 sb_min_blocksize(sb, 512);
1192 bh = sb_bread(sb, 0);
1193 if (bh == NULL) {
1194 printk(KERN_ERR "FAT: unable to read boot sector\n");
1195 goto out_fail;
1198 b = (struct fat_boot_sector *) bh->b_data;
1199 if (!b->reserved) {
1200 if (!silent)
1201 printk(KERN_ERR "FAT: bogus number of reserved sectors\n");
1202 brelse(bh);
1203 goto out_invalid;
1205 if (!b->fats) {
1206 if (!silent)
1207 printk(KERN_ERR "FAT: bogus number of FAT structure\n");
1208 brelse(bh);
1209 goto out_invalid;
1213 * Earlier we checked here that b->secs_track and b->head are nonzero,
1214 * but it turns out valid FAT filesystems can have zero there.
1217 media = b->media;
1218 if (!fat_valid_media(media)) {
1219 if (!silent)
1220 printk(KERN_ERR "FAT: invalid media value (0x%02x)\n",
1221 media);
1222 brelse(bh);
1223 goto out_invalid;
1225 logical_sector_size = get_unaligned_le16(&b->sector_size);
1226 if (!is_power_of_2(logical_sector_size)
1227 || (logical_sector_size < 512)
1228 || (logical_sector_size > 4096)) {
1229 if (!silent)
1230 printk(KERN_ERR "FAT: bogus logical sector size %u\n",
1231 logical_sector_size);
1232 brelse(bh);
1233 goto out_invalid;
1235 sbi->sec_per_clus = b->sec_per_clus;
1236 if (!is_power_of_2(sbi->sec_per_clus)) {
1237 if (!silent)
1238 printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
1239 sbi->sec_per_clus);
1240 brelse(bh);
1241 goto out_invalid;
1244 if (logical_sector_size < sb->s_blocksize) {
1245 printk(KERN_ERR "FAT: logical sector size too small for device"
1246 " (logical sector size = %u)\n", logical_sector_size);
1247 brelse(bh);
1248 goto out_fail;
1250 if (logical_sector_size > sb->s_blocksize) {
1251 brelse(bh);
1253 if (!sb_set_blocksize(sb, logical_sector_size)) {
1254 printk(KERN_ERR "FAT: unable to set blocksize %u\n",
1255 logical_sector_size);
1256 goto out_fail;
1258 bh = sb_bread(sb, 0);
1259 if (bh == NULL) {
1260 printk(KERN_ERR "FAT: unable to read boot sector"
1261 " (logical sector size = %lu)\n",
1262 sb->s_blocksize);
1263 goto out_fail;
1265 b = (struct fat_boot_sector *) bh->b_data;
1268 sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
1269 sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
1270 sbi->fats = b->fats;
1271 sbi->fat_bits = 0; /* Don't know yet */
1272 sbi->fat_start = le16_to_cpu(b->reserved);
1273 sbi->fat_length = le16_to_cpu(b->fat_length);
1274 sbi->root_cluster = 0;
1275 sbi->free_clusters = -1; /* Don't know yet */
1276 sbi->free_clus_valid = 0;
1277 sbi->prev_free = FAT_START_ENT;
1279 if (!sbi->fat_length && b->fat32_length) {
1280 struct fat_boot_fsinfo *fsinfo;
1281 struct buffer_head *fsinfo_bh;
1283 /* Must be FAT32 */
1284 sbi->fat_bits = 32;
1285 sbi->fat_length = le32_to_cpu(b->fat32_length);
1286 sbi->root_cluster = le32_to_cpu(b->root_cluster);
1288 sb->s_maxbytes = 0xffffffff;
1290 /* MC - if info_sector is 0, don't multiply by 0 */
1291 sbi->fsinfo_sector = le16_to_cpu(b->info_sector);
1292 if (sbi->fsinfo_sector == 0)
1293 sbi->fsinfo_sector = 1;
1295 fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
1296 if (fsinfo_bh == NULL) {
1297 printk(KERN_ERR "FAT: bread failed, FSINFO block"
1298 " (sector = %lu)\n", sbi->fsinfo_sector);
1299 brelse(bh);
1300 goto out_fail;
1303 fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
1304 if (!IS_FSINFO(fsinfo)) {
1305 printk(KERN_WARNING "FAT: Invalid FSINFO signature: "
1306 "0x%08x, 0x%08x (sector = %lu)\n",
1307 le32_to_cpu(fsinfo->signature1),
1308 le32_to_cpu(fsinfo->signature2),
1309 sbi->fsinfo_sector);
1310 } else {
1311 if (sbi->options.usefree)
1312 sbi->free_clus_valid = 1;
1313 sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
1314 sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
1317 brelse(fsinfo_bh);
1320 sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
1321 sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
1323 sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
1324 sbi->dir_entries = get_unaligned_le16(&b->dir_entries);
1325 if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
1326 if (!silent)
1327 printk(KERN_ERR "FAT: bogus directroy-entries per block"
1328 " (%u)\n", sbi->dir_entries);
1329 brelse(bh);
1330 goto out_invalid;
1333 rootdir_sectors = sbi->dir_entries
1334 * sizeof(struct msdos_dir_entry) / sb->s_blocksize;
1335 sbi->data_start = sbi->dir_start + rootdir_sectors;
1336 total_sectors = get_unaligned_le16(&b->sectors);
1337 if (total_sectors == 0)
1338 total_sectors = le32_to_cpu(b->total_sect);
1340 total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
1342 if (sbi->fat_bits != 32)
1343 sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
1345 /* check that FAT table does not overflow */
1346 fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
1347 total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
1348 if (total_clusters > MAX_FAT(sb)) {
1349 if (!silent)
1350 printk(KERN_ERR "FAT: count of clusters too big (%u)\n",
1351 total_clusters);
1352 brelse(bh);
1353 goto out_invalid;
1356 sbi->max_cluster = total_clusters + FAT_START_ENT;
1357 /* check the free_clusters, it's not necessarily correct */
1358 if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
1359 sbi->free_clusters = -1;
1360 /* check the prev_free, it's not necessarily correct */
1361 sbi->prev_free %= sbi->max_cluster;
1362 if (sbi->prev_free < FAT_START_ENT)
1363 sbi->prev_free = FAT_START_ENT;
1365 brelse(bh);
1367 /* set up enough so that it can read an inode */
1368 fat_hash_init(sb);
1369 fat_ent_access_init(sb);
1372 * The low byte of FAT's first entry must have same value with
1373 * media-field. But in real world, too many devices is
1374 * writing wrong value. So, removed that validity check.
1376 * if (FAT_FIRST_ENT(sb, media) != first)
1379 error = -EINVAL;
1380 sprintf(buf, "cp%d", sbi->options.codepage);
1381 sbi->nls_disk = load_nls(buf);
1382 if (!sbi->nls_disk) {
1383 printk(KERN_ERR "FAT: codepage %s not found\n", buf);
1384 goto out_fail;
1387 /* FIXME: utf8 is using iocharset for upper/lower conversion */
1388 if (sbi->options.isvfat) {
1389 sbi->nls_io = load_nls(sbi->options.iocharset);
1390 if (!sbi->nls_io) {
1391 printk(KERN_ERR "FAT: IO charset %s not found\n",
1392 sbi->options.iocharset);
1393 goto out_fail;
1397 error = -ENOMEM;
1398 root_inode = new_inode(sb);
1399 if (!root_inode)
1400 goto out_fail;
1401 root_inode->i_ino = MSDOS_ROOT_INO;
1402 root_inode->i_version = 1;
1403 error = fat_read_root(root_inode);
1404 if (error < 0)
1405 goto out_fail;
1406 error = -ENOMEM;
1407 insert_inode_hash(root_inode);
1408 sb->s_root = d_alloc_root(root_inode);
1409 if (!sb->s_root) {
1410 printk(KERN_ERR "FAT: get root inode failed\n");
1411 goto out_fail;
1414 return 0;
1416 out_invalid:
1417 error = -EINVAL;
1418 if (!silent)
1419 printk(KERN_INFO "VFS: Can't find a valid FAT filesystem"
1420 " on dev %s.\n", sb->s_id);
1422 out_fail:
1423 if (root_inode)
1424 iput(root_inode);
1425 if (sbi->nls_io)
1426 unload_nls(sbi->nls_io);
1427 if (sbi->nls_disk)
1428 unload_nls(sbi->nls_disk);
1429 if (sbi->options.iocharset != fat_default_iocharset)
1430 kfree(sbi->options.iocharset);
1431 sb->s_fs_info = NULL;
1432 kfree(sbi);
1433 return error;
1436 EXPORT_SYMBOL_GPL(fat_fill_super);
1439 * helper function for fat_flush_inodes. This writes both the inode
1440 * and the file data blocks, waiting for in flight data blocks before
1441 * the start of the call. It does not wait for any io started
1442 * during the call
1444 static int writeback_inode(struct inode *inode)
1447 int ret;
1448 struct address_space *mapping = inode->i_mapping;
1449 struct writeback_control wbc = {
1450 .sync_mode = WB_SYNC_NONE,
1451 .nr_to_write = 0,
1453 /* if we used WB_SYNC_ALL, sync_inode waits for the io for the
1454 * inode to finish. So WB_SYNC_NONE is sent down to sync_inode
1455 * and filemap_fdatawrite is used for the data blocks
1457 ret = sync_inode(inode, &wbc);
1458 if (!ret)
1459 ret = filemap_fdatawrite(mapping);
1460 return ret;
1464 * write data and metadata corresponding to i1 and i2. The io is
1465 * started but we do not wait for any of it to finish.
1467 * filemap_flush is used for the block device, so if there is a dirty
1468 * page for a block already in flight, we will not wait and start the
1469 * io over again
1471 int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
1473 int ret = 0;
1474 if (!MSDOS_SB(sb)->options.flush)
1475 return 0;
1476 if (i1)
1477 ret = writeback_inode(i1);
1478 if (!ret && i2)
1479 ret = writeback_inode(i2);
1480 if (!ret) {
1481 struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
1482 ret = filemap_flush(mapping);
1484 return ret;
1486 EXPORT_SYMBOL_GPL(fat_flush_inodes);
1488 static int __init init_fat_fs(void)
1490 int err;
1492 err = fat_cache_init();
1493 if (err)
1494 return err;
1496 err = fat_init_inodecache();
1497 if (err)
1498 goto failed;
1500 return 0;
1502 failed:
1503 fat_cache_destroy();
1504 return err;
1507 static void __exit exit_fat_fs(void)
1509 fat_cache_destroy();
1510 fat_destroy_inodecache();
1513 module_init(init_fat_fs)
1514 module_exit(exit_fat_fs)
1516 MODULE_LICENSE("GPL");