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