1
// SPDX-License-Identifier: GPL-2.0-or-later
2
/*
3
 *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
4
 */
5

6
#include <linux/fs_context.h>
7
#include <linux/fs_parser.h>
8
#include <linux/module.h>
9
#include <linux/init.h>
10
#include <linux/time.h>
11
#include <linux/mount.h>
12
#include <linux/cred.h>
13
#include <linux/statfs.h>
14
#include <linux/seq_file.h>
15
#include <linux/blkdev.h>
16
#include <linux/fs_struct.h>
17
#include <linux/iversion.h>
18
#include <linux/nls.h>
19
#include <linux/buffer_head.h>
20
#include <linux/magic.h>
21

22
#include "exfat_raw.h"
23
#include "exfat_fs.h"
24

25
static char exfat_default_iocharset[] = CONFIG_EXFAT_DEFAULT_IOCHARSET;
26
static struct kmem_cache *exfat_inode_cachep;
27

28
static void exfat_free_iocharset(struct exfat_sb_info *sbi)
29
{
30
	if (sbi->options.iocharset != exfat_default_iocharset)
31
		kfree(sbi->options.iocharset);
32
}
33

34
static void exfat_set_iocharset(struct exfat_mount_options *opts,
35
				char *iocharset)
36
{
37
	opts->iocharset = iocharset;
38
	if (!strcmp(opts->iocharset, "utf8"))
39
		opts->utf8 = 1;
40
	else
41
		opts->utf8 = 0;
42
}
43

44
static void exfat_put_super(struct super_block *sb)
45
{
46
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
47

48
	mutex_lock(&sbi->s_lock);
49
	exfat_clear_volume_dirty(sb);
50
	exfat_free_bitmap(sbi);
51
	brelse(sbi->boot_bh);
52
	mutex_unlock(&sbi->s_lock);
53
}
54

55
static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
56
{
57
	struct super_block *sb = dentry->d_sb;
58
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
59
	unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
60

61
	buf->f_type = sb->s_magic;
62
	buf->f_bsize = sbi->cluster_size;
63
	buf->f_blocks = sbi->num_clusters - 2; /* clu 0 & 1 */
64
	buf->f_bfree = buf->f_blocks - sbi->used_clusters;
65
	buf->f_bavail = buf->f_bfree;
66
	buf->f_fsid = u64_to_fsid(id);
67
	/* Unicode utf16 255 characters */
68
	buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE;
69
	return 0;
70
}
71

72
static int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flags)
73
{
74
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
75
	struct boot_sector *p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
76

77
	/* retain persistent-flags */
78
	new_flags |= sbi->vol_flags_persistent;
79

80
	/* flags are not changed */
81
	if (sbi->vol_flags == new_flags)
82
		return 0;
83

84
	sbi->vol_flags = new_flags;
85

86
	/* skip updating volume dirty flag,
87
	 * if this volume has been mounted with read-only
88
	 */
89
	if (sb_rdonly(sb))
90
		return 0;
91

92
	p_boot->vol_flags = cpu_to_le16(new_flags);
93

94
	set_buffer_uptodate(sbi->boot_bh);
95
	mark_buffer_dirty(sbi->boot_bh);
96

97
	__sync_dirty_buffer(sbi->boot_bh, REQ_SYNC | REQ_FUA | REQ_PREFLUSH);
98

99
	return 0;
100
}
101

102
int exfat_set_volume_dirty(struct super_block *sb)
103
{
104
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
105

106
	return exfat_set_vol_flags(sb, sbi->vol_flags | VOLUME_DIRTY);
107
}
108

109
int exfat_clear_volume_dirty(struct super_block *sb)
110
{
111
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
112

113
	return exfat_set_vol_flags(sb, sbi->vol_flags & ~VOLUME_DIRTY);
114
}
115

116
static int exfat_show_options(struct seq_file *m, struct dentry *root)
117
{
118
	struct super_block *sb = root->d_sb;
119
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
120
	struct exfat_mount_options *opts = &sbi->options;
121

122
	/* Show partition info */
123
	if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
124
		seq_printf(m, ",uid=%u",
125
				from_kuid_munged(&init_user_ns, opts->fs_uid));
126
	if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
127
		seq_printf(m, ",gid=%u",
128
				from_kgid_munged(&init_user_ns, opts->fs_gid));
129
	seq_printf(m, ",fmask=%04o,dmask=%04o", opts->fs_fmask, opts->fs_dmask);
130
	if (opts->allow_utime)
131
		seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
132
	if (opts->utf8)
133
		seq_puts(m, ",iocharset=utf8");
134
	else if (sbi->nls_io)
135
		seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
136
	if (opts->errors == EXFAT_ERRORS_CONT)
137
		seq_puts(m, ",errors=continue");
138
	else if (opts->errors == EXFAT_ERRORS_PANIC)
139
		seq_puts(m, ",errors=panic");
140
	else
141
		seq_puts(m, ",errors=remount-ro");
142
	if (opts->discard)
143
		seq_puts(m, ",discard");
144
	if (opts->keep_last_dots)
145
		seq_puts(m, ",keep_last_dots");
146
	if (opts->sys_tz)
147
		seq_puts(m, ",sys_tz");
148
	else if (opts->time_offset)
149
		seq_printf(m, ",time_offset=%d", opts->time_offset);
150
	if (opts->zero_size_dir)
151
		seq_puts(m, ",zero_size_dir");
152
	return 0;
153
}
154

155
int exfat_force_shutdown(struct super_block *sb, u32 flags)
156
{
157
	int ret;
158
	struct exfat_sb_info *sbi = sb->s_fs_info;
159
	struct exfat_mount_options *opts = &sbi->options;
160

161
	if (exfat_forced_shutdown(sb))
162
		return 0;
163

164
	switch (flags) {
165
	case EXFAT_GOING_DOWN_DEFAULT:
166
	case EXFAT_GOING_DOWN_FULLSYNC:
167
		ret = bdev_freeze(sb->s_bdev);
168
		if (ret)
169
			return ret;
170
		bdev_thaw(sb->s_bdev);
171
		set_bit(EXFAT_FLAGS_SHUTDOWN, &sbi->s_exfat_flags);
172
		break;
173
	case EXFAT_GOING_DOWN_NOSYNC:
174
		set_bit(EXFAT_FLAGS_SHUTDOWN, &sbi->s_exfat_flags);
175
		break;
176
	default:
177
		return -EINVAL;
178
	}
179

180
	if (opts->discard)
181
		opts->discard = 0;
182
	return 0;
183
}
184

185
static void exfat_shutdown(struct super_block *sb)
186
{
187
	exfat_force_shutdown(sb, EXFAT_GOING_DOWN_NOSYNC);
188
}
189

190
static struct inode *exfat_alloc_inode(struct super_block *sb)
191
{
192
	struct exfat_inode_info *ei;
193

194
	ei = alloc_inode_sb(sb, exfat_inode_cachep, GFP_NOFS);
195
	if (!ei)
196
		return NULL;
197

198
	init_rwsem(&ei->truncate_lock);
199
	return &ei->vfs_inode;
200
}
201

202
static void exfat_free_inode(struct inode *inode)
203
{
204
	kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
205
}
206

207
static const struct super_operations exfat_sops = {
208
	.alloc_inode	= exfat_alloc_inode,
209
	.free_inode	= exfat_free_inode,
210
	.write_inode	= exfat_write_inode,
211
	.evict_inode	= exfat_evict_inode,
212
	.put_super	= exfat_put_super,
213
	.statfs		= exfat_statfs,
214
	.show_options	= exfat_show_options,
215
	.shutdown	= exfat_shutdown,
216
};
217

218
enum {
219
	Opt_uid,
220
	Opt_gid,
221
	Opt_umask,
222
	Opt_dmask,
223
	Opt_fmask,
224
	Opt_allow_utime,
225
	Opt_charset,
226
	Opt_errors,
227
	Opt_discard,
228
	Opt_keep_last_dots,
229
	Opt_sys_tz,
230
	Opt_time_offset,
231
	Opt_zero_size_dir,
232

233
	/* Deprecated options */
234
	Opt_utf8,
235
	Opt_debug,
236
	Opt_namecase,
237
	Opt_codepage,
238
};
239

240
static const struct constant_table exfat_param_enums[] = {
241
	{ "continue",		EXFAT_ERRORS_CONT },
242
	{ "panic",		EXFAT_ERRORS_PANIC },
243
	{ "remount-ro",		EXFAT_ERRORS_RO },
244
	{}
245
};
246

247
static const struct fs_parameter_spec exfat_parameters[] = {
248
	fsparam_uid("uid",			Opt_uid),
249
	fsparam_gid("gid",			Opt_gid),
250
	fsparam_u32oct("umask",			Opt_umask),
251
	fsparam_u32oct("dmask",			Opt_dmask),
252
	fsparam_u32oct("fmask",			Opt_fmask),
253
	fsparam_u32oct("allow_utime",		Opt_allow_utime),
254
	fsparam_string("iocharset",		Opt_charset),
255
	fsparam_enum("errors",			Opt_errors, exfat_param_enums),
256
	fsparam_flag_no("discard",		Opt_discard),
257
	fsparam_flag("keep_last_dots",		Opt_keep_last_dots),
258
	fsparam_flag("sys_tz",			Opt_sys_tz),
259
	fsparam_s32("time_offset",		Opt_time_offset),
260
	fsparam_flag_no("zero_size_dir",	Opt_zero_size_dir),
261
	__fsparam(NULL, "utf8",			Opt_utf8, fs_param_deprecated,
262
		  NULL),
263
	__fsparam(NULL, "debug",		Opt_debug, fs_param_deprecated,
264
		  NULL),
265
	__fsparam(fs_param_is_u32, "namecase",	Opt_namecase,
266
		  fs_param_deprecated, NULL),
267
	__fsparam(fs_param_is_u32, "codepage",	Opt_codepage,
268
		  fs_param_deprecated, NULL),
269
	{}
270
};
271

272
static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
273
{
274
	struct exfat_sb_info *sbi = fc->s_fs_info;
275
	struct exfat_mount_options *opts = &sbi->options;
276
	struct fs_parse_result result;
277
	int opt;
278

279
	opt = fs_parse(fc, exfat_parameters, param, &result);
280
	if (opt < 0)
281
		return opt;
282

283
	switch (opt) {
284
	case Opt_uid:
285
		opts->fs_uid = result.uid;
286
		break;
287
	case Opt_gid:
288
		opts->fs_gid = result.gid;
289
		break;
290
	case Opt_umask:
291
		opts->fs_fmask = result.uint_32;
292
		opts->fs_dmask = result.uint_32;
293
		break;
294
	case Opt_dmask:
295
		opts->fs_dmask = result.uint_32;
296
		break;
297
	case Opt_fmask:
298
		opts->fs_fmask = result.uint_32;
299
		break;
300
	case Opt_allow_utime:
301
		opts->allow_utime = result.uint_32 & 0022;
302
		break;
303
	case Opt_charset:
304
		exfat_free_iocharset(sbi);
305
		exfat_set_iocharset(opts, param->string);
306
		param->string = NULL;
307
		break;
308
	case Opt_errors:
309
		opts->errors = result.uint_32;
310
		break;
311
	case Opt_discard:
312
		opts->discard = !result.negated;
313
		break;
314
	case Opt_keep_last_dots:
315
		opts->keep_last_dots = 1;
316
		break;
317
	case Opt_sys_tz:
318
		opts->sys_tz = 1;
319
		break;
320
	case Opt_time_offset:
321
		/*
322
		 * Make the limit 24 just in case someone invents something
323
		 * unusual.
324
		 */
325
		if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
326
			return -EINVAL;
327
		opts->time_offset = result.int_32;
328
		break;
329
	case Opt_zero_size_dir:
330
		opts->zero_size_dir = !result.negated;
331
		break;
332
	case Opt_utf8:
333
	case Opt_debug:
334
	case Opt_namecase:
335
	case Opt_codepage:
336
		break;
337
	default:
338
		return -EINVAL;
339
	}
340

341
	return 0;
342
}
343

344
static void exfat_hash_init(struct super_block *sb)
345
{
346
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
347
	int i;
348

349
	spin_lock_init(&sbi->inode_hash_lock);
350
	for (i = 0; i < EXFAT_HASH_SIZE; i++)
351
		INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
352
}
353

354
static int exfat_read_root(struct inode *inode, struct exfat_chain *root_clu)
355
{
356
	struct super_block *sb = inode->i_sb;
357
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
358
	struct exfat_inode_info *ei = EXFAT_I(inode);
359
	int num_subdirs;
360

361
	exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
362
	ei->entry = -1;
363
	ei->start_clu = sbi->root_dir;
364
	ei->flags = ALLOC_FAT_CHAIN;
365
	ei->type = TYPE_DIR;
366
	ei->version = 0;
367
	ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
368
	ei->hint_stat.eidx = 0;
369
	ei->hint_stat.clu = sbi->root_dir;
370
	ei->hint_femp.eidx = EXFAT_HINT_NONE;
371

372
	i_size_write(inode, EXFAT_CLU_TO_B(root_clu->size, sbi));
373

374
	num_subdirs = exfat_count_dir_entries(sb, root_clu);
375
	if (num_subdirs < 0)
376
		return -EIO;
377
	set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
378

379
	inode->i_uid = sbi->options.fs_uid;
380
	inode->i_gid = sbi->options.fs_gid;
381
	inode_inc_iversion(inode);
382
	inode->i_generation = 0;
383
	inode->i_mode = exfat_make_mode(sbi, EXFAT_ATTR_SUBDIR, 0777);
384
	inode->i_op = &exfat_dir_inode_operations;
385
	inode->i_fop = &exfat_dir_operations;
386

387
	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9;
388
	ei->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
389

390
	exfat_save_attr(inode, EXFAT_ATTR_SUBDIR);
391
	ei->i_crtime = simple_inode_init_ts(inode);
392
	exfat_truncate_inode_atime(inode);
393
	return 0;
394
}
395

396
static int exfat_calibrate_blocksize(struct super_block *sb, int logical_sect)
397
{
398
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
399

400
	if (!is_power_of_2(logical_sect)) {
401
		exfat_err(sb, "bogus logical sector size %u", logical_sect);
402
		return -EIO;
403
	}
404

405
	if (logical_sect < sb->s_blocksize) {
406
		exfat_err(sb, "logical sector size too small for device (logical sector size = %u)",
407
			  logical_sect);
408
		return -EIO;
409
	}
410

411
	if (logical_sect > sb->s_blocksize) {
412
		brelse(sbi->boot_bh);
413
		sbi->boot_bh = NULL;
414

415
		if (!sb_set_blocksize(sb, logical_sect)) {
416
			exfat_err(sb, "unable to set blocksize %u",
417
				  logical_sect);
418
			return -EIO;
419
		}
420
		sbi->boot_bh = sb_bread(sb, 0);
421
		if (!sbi->boot_bh) {
422
			exfat_err(sb, "unable to read boot sector (logical sector size = %lu)",
423
				  sb->s_blocksize);
424
			return -EIO;
425
		}
426
	}
427
	return 0;
428
}
429

430
static int exfat_read_boot_sector(struct super_block *sb)
431
{
432
	struct boot_sector *p_boot;
433
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
434

435
	/* set block size to read super block */
436
	sb_min_blocksize(sb, 512);
437

438
	/* read boot sector */
439
	sbi->boot_bh = sb_bread(sb, 0);
440
	if (!sbi->boot_bh) {
441
		exfat_err(sb, "unable to read boot sector");
442
		return -EIO;
443
	}
444
	p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
445

446
	/* check the validity of BOOT */
447
	if (le16_to_cpu((p_boot->signature)) != BOOT_SIGNATURE) {
448
		exfat_err(sb, "invalid boot record signature");
449
		return -EINVAL;
450
	}
451

452
	if (memcmp(p_boot->fs_name, STR_EXFAT, BOOTSEC_FS_NAME_LEN)) {
453
		exfat_err(sb, "invalid fs_name"); /* fs_name may unprintable */
454
		return -EINVAL;
455
	}
456

457
	/*
458
	 * must_be_zero field must be filled with zero to prevent mounting
459
	 * from FAT volume.
460
	 */
461
	if (memchr_inv(p_boot->must_be_zero, 0, sizeof(p_boot->must_be_zero)))
462
		return -EINVAL;
463

464
	if (p_boot->num_fats != 1 && p_boot->num_fats != 2) {
465
		exfat_err(sb, "bogus number of FAT structure");
466
		return -EINVAL;
467
	}
468

469
	/*
470
	 * sect_size_bits could be at least 9 and at most 12.
471
	 */
472
	if (p_boot->sect_size_bits < EXFAT_MIN_SECT_SIZE_BITS ||
473
	    p_boot->sect_size_bits > EXFAT_MAX_SECT_SIZE_BITS) {
474
		exfat_err(sb, "bogus sector size bits : %u",
475
				p_boot->sect_size_bits);
476
		return -EINVAL;
477
	}
478

479
	/*
480
	 * sect_per_clus_bits could be at least 0 and at most 25 - sect_size_bits.
481
	 */
482
	if (p_boot->sect_per_clus_bits > EXFAT_MAX_SECT_PER_CLUS_BITS(p_boot)) {
483
		exfat_err(sb, "bogus sectors bits per cluster : %u",
484
				p_boot->sect_per_clus_bits);
485
		return -EINVAL;
486
	}
487

488
	sbi->sect_per_clus = 1 << p_boot->sect_per_clus_bits;
489
	sbi->sect_per_clus_bits = p_boot->sect_per_clus_bits;
490
	sbi->cluster_size_bits = p_boot->sect_per_clus_bits +
491
		p_boot->sect_size_bits;
492
	sbi->cluster_size = 1 << sbi->cluster_size_bits;
493
	sbi->num_FAT_sectors = le32_to_cpu(p_boot->fat_length);
494
	sbi->FAT1_start_sector = le32_to_cpu(p_boot->fat_offset);
495
	sbi->FAT2_start_sector = le32_to_cpu(p_boot->fat_offset);
496
	if (p_boot->num_fats == 2)
497
		sbi->FAT2_start_sector += sbi->num_FAT_sectors;
498
	sbi->data_start_sector = le32_to_cpu(p_boot->clu_offset);
499
	sbi->num_sectors = le64_to_cpu(p_boot->vol_length);
500
	/* because the cluster index starts with 2 */
501
	sbi->num_clusters = le32_to_cpu(p_boot->clu_count) +
502
		EXFAT_RESERVED_CLUSTERS;
503

504
	sbi->root_dir = le32_to_cpu(p_boot->root_cluster);
505
	sbi->dentries_per_clu = 1 <<
506
		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
507

508
	sbi->vol_flags = le16_to_cpu(p_boot->vol_flags);
509
	sbi->vol_flags_persistent = sbi->vol_flags & (VOLUME_DIRTY | MEDIA_FAILURE);
510
	sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
511

512
	/* check consistencies */
513
	if ((u64)sbi->num_FAT_sectors << p_boot->sect_size_bits <
514
	    (u64)sbi->num_clusters * 4) {
515
		exfat_err(sb, "bogus fat length");
516
		return -EINVAL;
517
	}
518

519
	if (sbi->data_start_sector <
520
	    (u64)sbi->FAT1_start_sector +
521
	    (u64)sbi->num_FAT_sectors * p_boot->num_fats) {
522
		exfat_err(sb, "bogus data start sector");
523
		return -EINVAL;
524
	}
525

526
	if (sbi->vol_flags & VOLUME_DIRTY)
527
		exfat_warn(sb, "Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
528
	if (sbi->vol_flags & MEDIA_FAILURE)
529
		exfat_warn(sb, "Medium has reported failures. Some data may be lost.");
530

531
	/* exFAT file size is limited by a disk volume size */
532
	sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) <<
533
		sbi->cluster_size_bits;
534

535
	/* check logical sector size */
536
	if (exfat_calibrate_blocksize(sb, 1 << p_boot->sect_size_bits))
537
		return -EIO;
538

539
	return 0;
540
}
541

542
static int exfat_verify_boot_region(struct super_block *sb)
543
{
544
	struct buffer_head *bh = NULL;
545
	u32 chksum = 0;
546
	__le32 *p_sig, *p_chksum;
547
	int sn, i;
548

549
	/* read boot sector sub-regions */
550
	for (sn = 0; sn < 11; sn++) {
551
		bh = sb_bread(sb, sn);
552
		if (!bh)
553
			return -EIO;
554

555
		if (sn != 0 && sn <= 8) {
556
			/* extended boot sector sub-regions */
557
			p_sig = (__le32 *)&bh->b_data[sb->s_blocksize - 4];
558
			if (le32_to_cpu(*p_sig) != EXBOOT_SIGNATURE)
559
				exfat_warn(sb, "Invalid exboot-signature(sector = %d): 0x%08x",
560
					   sn, le32_to_cpu(*p_sig));
561
		}
562

563
		chksum = exfat_calc_chksum32(bh->b_data, sb->s_blocksize,
564
			chksum, sn ? CS_DEFAULT : CS_BOOT_SECTOR);
565
		brelse(bh);
566
	}
567

568
	/* boot checksum sub-regions */
569
	bh = sb_bread(sb, sn);
570
	if (!bh)
571
		return -EIO;
572

573
	for (i = 0; i < sb->s_blocksize; i += sizeof(u32)) {
574
		p_chksum = (__le32 *)&bh->b_data[i];
575
		if (le32_to_cpu(*p_chksum) != chksum) {
576
			exfat_err(sb, "Invalid boot checksum (boot checksum : 0x%08x, checksum : 0x%08x)",
577
				  le32_to_cpu(*p_chksum), chksum);
578
			brelse(bh);
579
			return -EINVAL;
580
		}
581
	}
582
	brelse(bh);
583
	return 0;
584
}
585

586
/* mount the file system volume */
587
static int __exfat_fill_super(struct super_block *sb,
588
		struct exfat_chain *root_clu)
589
{
590
	int ret;
591
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
592

593
	ret = exfat_read_boot_sector(sb);
594
	if (ret) {
595
		exfat_err(sb, "failed to read boot sector");
596
		goto free_bh;
597
	}
598

599
	ret = exfat_verify_boot_region(sb);
600
	if (ret) {
601
		exfat_err(sb, "invalid boot region");
602
		goto free_bh;
603
	}
604

605
	/*
606
	 * Call exfat_count_num_cluster() before searching for up-case and
607
	 * bitmap directory entries to avoid infinite loop if they are missing
608
	 * and the cluster chain includes a loop.
609
	 */
610
	exfat_chain_set(root_clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
611
	ret = exfat_count_num_clusters(sb, root_clu, &root_clu->size);
612
	if (ret) {
613
		exfat_err(sb, "failed to count the number of clusters in root");
614
		goto free_bh;
615
	}
616

617
	ret = exfat_create_upcase_table(sb);
618
	if (ret) {
619
		exfat_err(sb, "failed to load upcase table");
620
		goto free_bh;
621
	}
622

623
	ret = exfat_load_bitmap(sb);
624
	if (ret) {
625
		exfat_err(sb, "failed to load alloc-bitmap");
626
		goto free_bh;
627
	}
628

629
	ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
630
	if (ret) {
631
		exfat_err(sb, "failed to scan clusters");
632
		goto free_alloc_bitmap;
633
	}
634

635
	return 0;
636

637
free_alloc_bitmap:
638
	exfat_free_bitmap(sbi);
639
free_bh:
640
	brelse(sbi->boot_bh);
641
	return ret;
642
}
643

644
static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
645
{
646
	struct exfat_sb_info *sbi = sb->s_fs_info;
647
	struct exfat_mount_options *opts = &sbi->options;
648
	struct inode *root_inode;
649
	struct exfat_chain root_clu;
650
	int err;
651

652
	if (opts->allow_utime == (unsigned short)-1)
653
		opts->allow_utime = ~opts->fs_dmask & 0022;
654

655
	if (opts->discard && !bdev_max_discard_sectors(sb->s_bdev)) {
656
		exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
657
		opts->discard = 0;
658
	}
659

660
	sb->s_flags |= SB_NODIRATIME;
661
	sb->s_magic = EXFAT_SUPER_MAGIC;
662
	sb->s_op = &exfat_sops;
663

664
	sb->s_time_gran = 10 * NSEC_PER_MSEC;
665
	sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
666
	sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
667

668
	err = __exfat_fill_super(sb, &root_clu);
669
	if (err) {
670
		exfat_err(sb, "failed to recognize exfat type");
671
		goto check_nls_io;
672
	}
673

674
	/* set up enough so that it can read an inode */
675
	exfat_hash_init(sb);
676

677
	if (sbi->options.utf8)
678
		set_default_d_op(sb, &exfat_utf8_dentry_ops);
679
	else {
680
		sbi->nls_io = load_nls(sbi->options.iocharset);
681
		if (!sbi->nls_io) {
682
			exfat_err(sb, "IO charset %s not found",
683
				  sbi->options.iocharset);
684
			err = -EINVAL;
685
			goto free_table;
686
		}
687
		set_default_d_op(sb, &exfat_dentry_ops);
688
	}
689

690
	root_inode = new_inode(sb);
691
	if (!root_inode) {
692
		exfat_err(sb, "failed to allocate root inode");
693
		err = -ENOMEM;
694
		goto free_table;
695
	}
696

697
	root_inode->i_ino = EXFAT_ROOT_INO;
698
	inode_set_iversion(root_inode, 1);
699
	err = exfat_read_root(root_inode, &root_clu);
700
	if (err) {
701
		exfat_err(sb, "failed to initialize root inode");
702
		goto put_inode;
703
	}
704

705
	exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
706
	insert_inode_hash(root_inode);
707

708
	sb->s_root = d_make_root(root_inode);
709
	if (!sb->s_root) {
710
		exfat_err(sb, "failed to get the root dentry");
711
		err = -ENOMEM;
712
		goto free_table;
713
	}
714

715
	return 0;
716

717
put_inode:
718
	iput(root_inode);
719
	sb->s_root = NULL;
720

721
free_table:
722
	exfat_free_bitmap(sbi);
723
	brelse(sbi->boot_bh);
724

725
check_nls_io:
726
	return err;
727
}
728

729
static int exfat_get_tree(struct fs_context *fc)
730
{
731
	return get_tree_bdev(fc, exfat_fill_super);
732
}
733

734
static void exfat_free_sbi(struct exfat_sb_info *sbi)
735
{
736
	exfat_free_iocharset(sbi);
737
	kfree(sbi);
738
}
739

740
static void exfat_free(struct fs_context *fc)
741
{
742
	struct exfat_sb_info *sbi = fc->s_fs_info;
743

744
	if (sbi)
745
		exfat_free_sbi(sbi);
746
}
747

748
static int exfat_reconfigure(struct fs_context *fc)
749
{
750
	struct super_block *sb = fc->root->d_sb;
751
	struct exfat_sb_info *remount_sbi = fc->s_fs_info;
752
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
753
	struct exfat_mount_options *new_opts = &remount_sbi->options;
754
	struct exfat_mount_options *cur_opts = &sbi->options;
755

756
	fc->sb_flags |= SB_NODIRATIME;
757

758
	sync_filesystem(sb);
759
	mutex_lock(&sbi->s_lock);
760
	exfat_clear_volume_dirty(sb);
761
	mutex_unlock(&sbi->s_lock);
762

763
	if (new_opts->allow_utime == (unsigned short)-1)
764
		new_opts->allow_utime = ~new_opts->fs_dmask & 0022;
765

766
	/*
767
	 * Since the old settings of these mount options are cached in
768
	 * inodes or dentries, they cannot be modified dynamically.
769
	 */
770
	if (strcmp(new_opts->iocharset, cur_opts->iocharset) ||
771
	    new_opts->keep_last_dots != cur_opts->keep_last_dots ||
772
	    new_opts->sys_tz != cur_opts->sys_tz ||
773
	    new_opts->time_offset != cur_opts->time_offset ||
774
	    !uid_eq(new_opts->fs_uid, cur_opts->fs_uid) ||
775
	    !gid_eq(new_opts->fs_gid, cur_opts->fs_gid) ||
776
	    new_opts->fs_fmask != cur_opts->fs_fmask ||
777
	    new_opts->fs_dmask != cur_opts->fs_dmask ||
778
	    new_opts->allow_utime != cur_opts->allow_utime)
779
		return -EINVAL;
780

781
	if (new_opts->discard != cur_opts->discard &&
782
	    new_opts->discard &&
783
	    !bdev_max_discard_sectors(sb->s_bdev)) {
784
		exfat_warn(sb, "remounting with \"discard\" option, but the device does not support discard");
785
		return -EINVAL;
786
	}
787

788
	swap(*cur_opts, *new_opts);
789

790
	return 0;
791
}
792

793
static const struct fs_context_operations exfat_context_ops = {
794
	.parse_param	= exfat_parse_param,
795
	.get_tree	= exfat_get_tree,
796
	.free		= exfat_free,
797
	.reconfigure	= exfat_reconfigure,
798
};
799

800
static int exfat_init_fs_context(struct fs_context *fc)
801
{
802
	struct exfat_sb_info *sbi;
803

804
	sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
805
	if (!sbi)
806
		return -ENOMEM;
807

808
	mutex_init(&sbi->s_lock);
809
	mutex_init(&sbi->bitmap_lock);
810
	ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
811
			DEFAULT_RATELIMIT_BURST);
812

813
	sbi->options.fs_uid = current_uid();
814
	sbi->options.fs_gid = current_gid();
815
	sbi->options.fs_fmask = current->fs->umask;
816
	sbi->options.fs_dmask = current->fs->umask;
817
	sbi->options.allow_utime = -1;
818
	sbi->options.errors = EXFAT_ERRORS_RO;
819
	exfat_set_iocharset(&sbi->options, exfat_default_iocharset);
820

821
	fc->s_fs_info = sbi;
822
	fc->ops = &exfat_context_ops;
823
	return 0;
824
}
825

826
static void delayed_free(struct rcu_head *p)
827
{
828
	struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu);
829

830
	unload_nls(sbi->nls_io);
831
	exfat_free_upcase_table(sbi);
832
	exfat_free_sbi(sbi);
833
}
834

835
static void exfat_kill_sb(struct super_block *sb)
836
{
837
	struct exfat_sb_info *sbi = sb->s_fs_info;
838

839
	kill_block_super(sb);
840
	if (sbi)
841
		call_rcu(&sbi->rcu, delayed_free);
842
}
843

844
static struct file_system_type exfat_fs_type = {
845
	.owner			= THIS_MODULE,
846
	.name			= "exfat",
847
	.init_fs_context	= exfat_init_fs_context,
848
	.parameters		= exfat_parameters,
849
	.kill_sb		= exfat_kill_sb,
850
	.fs_flags		= FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
851
};
852

853
static void exfat_inode_init_once(void *foo)
854
{
855
	struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
856

857
	spin_lock_init(&ei->cache_lru_lock);
858
	ei->nr_caches = 0;
859
	ei->cache_valid_id = EXFAT_CACHE_VALID + 1;
860
	INIT_LIST_HEAD(&ei->cache_lru);
861
	INIT_HLIST_NODE(&ei->i_hash_fat);
862
	inode_init_once(&ei->vfs_inode);
863
}
864

865
static int __init init_exfat_fs(void)
866
{
867
	int err;
868

869
	err = exfat_cache_init();
870
	if (err)
871
		return err;
872

873
	exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
874
			sizeof(struct exfat_inode_info),
875
			0, SLAB_RECLAIM_ACCOUNT,
876
			exfat_inode_init_once);
877
	if (!exfat_inode_cachep) {
878
		err = -ENOMEM;
879
		goto shutdown_cache;
880
	}
881

882
	err = register_filesystem(&exfat_fs_type);
883
	if (err)
884
		goto destroy_cache;
885

886
	return 0;
887

888
destroy_cache:
889
	kmem_cache_destroy(exfat_inode_cachep);
890
shutdown_cache:
891
	exfat_cache_shutdown();
892
	return err;
893
}
894

895
static void __exit exit_exfat_fs(void)
896
{
897
	/*
898
	 * Make sure all delayed rcu free inodes are flushed before we
899
	 * destroy cache.
900
	 */
901
	rcu_barrier();
902
	kmem_cache_destroy(exfat_inode_cachep);
903
	unregister_filesystem(&exfat_fs_type);
904
	exfat_cache_shutdown();
905
}
906

907
module_init(init_exfat_fs);
908
module_exit(exit_exfat_fs);
909

910
MODULE_ALIAS_FS("exfat");
911
MODULE_LICENSE("GPL");
912
MODULE_DESCRIPTION("exFAT filesystem support");
913
MODULE_AUTHOR("Samsung Electronics Co., Ltd.");
914

915