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