xref: /linux/fs/exfat/super.c (revision 79e03f29fc84db76f78834b1f73ed329b377d753)
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_delayed_free(struct rcu_head *p)
35 {
36 	struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu);
37 
38 	unload_nls(sbi->nls_io);
39 	exfat_free_iocharset(sbi);
40 	exfat_free_upcase_table(sbi);
41 	kfree(sbi);
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_free_bitmap(sbi);
50 	brelse(sbi->boot_bh);
51 	mutex_unlock(&sbi->s_lock);
52 
53 	call_rcu(&sbi->rcu, exfat_delayed_free);
54 }
55 
56 static int exfat_sync_fs(struct super_block *sb, int wait)
57 {
58 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
59 	int err = 0;
60 
61 	if (!wait)
62 		return 0;
63 
64 	/* If there are some dirty buffers in the bdev inode */
65 	mutex_lock(&sbi->s_lock);
66 	sync_blockdev(sb->s_bdev);
67 	if (exfat_clear_volume_dirty(sb))
68 		err = -EIO;
69 	mutex_unlock(&sbi->s_lock);
70 	return err;
71 }
72 
73 static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
74 {
75 	struct super_block *sb = dentry->d_sb;
76 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
77 	unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
78 
79 	if (sbi->used_clusters == EXFAT_CLUSTERS_UNTRACKED) {
80 		mutex_lock(&sbi->s_lock);
81 		if (exfat_count_used_clusters(sb, &sbi->used_clusters)) {
82 			mutex_unlock(&sbi->s_lock);
83 			return -EIO;
84 		}
85 		mutex_unlock(&sbi->s_lock);
86 	}
87 
88 	buf->f_type = sb->s_magic;
89 	buf->f_bsize = sbi->cluster_size;
90 	buf->f_blocks = sbi->num_clusters - 2; /* clu 0 & 1 */
91 	buf->f_bfree = buf->f_blocks - sbi->used_clusters;
92 	buf->f_bavail = buf->f_bfree;
93 	buf->f_fsid = u64_to_fsid(id);
94 	/* Unicode utf16 255 characters */
95 	buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE;
96 	return 0;
97 }
98 
99 static int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flags)
100 {
101 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
102 	struct boot_sector *p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
103 	bool sync;
104 
105 	/* retain persistent-flags */
106 	new_flags |= sbi->vol_flags_persistent;
107 
108 	/* flags are not changed */
109 	if (sbi->vol_flags == new_flags)
110 		return 0;
111 
112 	sbi->vol_flags = new_flags;
113 
114 	/* skip updating volume dirty flag,
115 	 * if this volume has been mounted with read-only
116 	 */
117 	if (sb_rdonly(sb))
118 		return 0;
119 
120 	p_boot->vol_flags = cpu_to_le16(new_flags);
121 
122 	if ((new_flags & VOLUME_DIRTY) && !buffer_dirty(sbi->boot_bh))
123 		sync = true;
124 	else
125 		sync = false;
126 
127 	set_buffer_uptodate(sbi->boot_bh);
128 	mark_buffer_dirty(sbi->boot_bh);
129 
130 	if (sync)
131 		sync_dirty_buffer(sbi->boot_bh);
132 	return 0;
133 }
134 
135 int exfat_set_volume_dirty(struct super_block *sb)
136 {
137 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
138 
139 	return exfat_set_vol_flags(sb, sbi->vol_flags | VOLUME_DIRTY);
140 }
141 
142 int exfat_clear_volume_dirty(struct super_block *sb)
143 {
144 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
145 
146 	return exfat_set_vol_flags(sb, sbi->vol_flags & ~VOLUME_DIRTY);
147 }
148 
149 static int exfat_show_options(struct seq_file *m, struct dentry *root)
150 {
151 	struct super_block *sb = root->d_sb;
152 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
153 	struct exfat_mount_options *opts = &sbi->options;
154 
155 	/* Show partition info */
156 	if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
157 		seq_printf(m, ",uid=%u",
158 				from_kuid_munged(&init_user_ns, opts->fs_uid));
159 	if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
160 		seq_printf(m, ",gid=%u",
161 				from_kgid_munged(&init_user_ns, opts->fs_gid));
162 	seq_printf(m, ",fmask=%04o,dmask=%04o", opts->fs_fmask, opts->fs_dmask);
163 	if (opts->allow_utime)
164 		seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
165 	if (opts->utf8)
166 		seq_puts(m, ",iocharset=utf8");
167 	else if (sbi->nls_io)
168 		seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
169 	if (opts->errors == EXFAT_ERRORS_CONT)
170 		seq_puts(m, ",errors=continue");
171 	else if (opts->errors == EXFAT_ERRORS_PANIC)
172 		seq_puts(m, ",errors=panic");
173 	else
174 		seq_puts(m, ",errors=remount-ro");
175 	if (opts->discard)
176 		seq_puts(m, ",discard");
177 	if (opts->time_offset)
178 		seq_printf(m, ",time_offset=%d", opts->time_offset);
179 	return 0;
180 }
181 
182 static struct inode *exfat_alloc_inode(struct super_block *sb)
183 {
184 	struct exfat_inode_info *ei;
185 
186 	ei = kmem_cache_alloc(exfat_inode_cachep, GFP_NOFS);
187 	if (!ei)
188 		return NULL;
189 
190 	init_rwsem(&ei->truncate_lock);
191 	return &ei->vfs_inode;
192 }
193 
194 static void exfat_free_inode(struct inode *inode)
195 {
196 	kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
197 }
198 
199 static const struct super_operations exfat_sops = {
200 	.alloc_inode	= exfat_alloc_inode,
201 	.free_inode	= exfat_free_inode,
202 	.write_inode	= exfat_write_inode,
203 	.evict_inode	= exfat_evict_inode,
204 	.put_super	= exfat_put_super,
205 	.sync_fs	= exfat_sync_fs,
206 	.statfs		= exfat_statfs,
207 	.show_options	= exfat_show_options,
208 };
209 
210 enum {
211 	Opt_uid,
212 	Opt_gid,
213 	Opt_umask,
214 	Opt_dmask,
215 	Opt_fmask,
216 	Opt_allow_utime,
217 	Opt_charset,
218 	Opt_errors,
219 	Opt_discard,
220 	Opt_time_offset,
221 
222 	/* Deprecated options */
223 	Opt_utf8,
224 	Opt_debug,
225 	Opt_namecase,
226 	Opt_codepage,
227 };
228 
229 static const struct constant_table exfat_param_enums[] = {
230 	{ "continue",		EXFAT_ERRORS_CONT },
231 	{ "panic",		EXFAT_ERRORS_PANIC },
232 	{ "remount-ro",		EXFAT_ERRORS_RO },
233 	{}
234 };
235 
236 static const struct fs_parameter_spec exfat_parameters[] = {
237 	fsparam_u32("uid",			Opt_uid),
238 	fsparam_u32("gid",			Opt_gid),
239 	fsparam_u32oct("umask",			Opt_umask),
240 	fsparam_u32oct("dmask",			Opt_dmask),
241 	fsparam_u32oct("fmask",			Opt_fmask),
242 	fsparam_u32oct("allow_utime",		Opt_allow_utime),
243 	fsparam_string("iocharset",		Opt_charset),
244 	fsparam_enum("errors",			Opt_errors, exfat_param_enums),
245 	fsparam_flag("discard",			Opt_discard),
246 	fsparam_s32("time_offset",		Opt_time_offset),
247 	__fsparam(NULL, "utf8",			Opt_utf8, fs_param_deprecated,
248 		  NULL),
249 	__fsparam(NULL, "debug",		Opt_debug, fs_param_deprecated,
250 		  NULL),
251 	__fsparam(fs_param_is_u32, "namecase",	Opt_namecase,
252 		  fs_param_deprecated, NULL),
253 	__fsparam(fs_param_is_u32, "codepage",	Opt_codepage,
254 		  fs_param_deprecated, NULL),
255 	{}
256 };
257 
258 static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
259 {
260 	struct exfat_sb_info *sbi = fc->s_fs_info;
261 	struct exfat_mount_options *opts = &sbi->options;
262 	struct fs_parse_result result;
263 	int opt;
264 
265 	opt = fs_parse(fc, exfat_parameters, param, &result);
266 	if (opt < 0)
267 		return opt;
268 
269 	switch (opt) {
270 	case Opt_uid:
271 		opts->fs_uid = make_kuid(current_user_ns(), result.uint_32);
272 		break;
273 	case Opt_gid:
274 		opts->fs_gid = make_kgid(current_user_ns(), result.uint_32);
275 		break;
276 	case Opt_umask:
277 		opts->fs_fmask = result.uint_32;
278 		opts->fs_dmask = result.uint_32;
279 		break;
280 	case Opt_dmask:
281 		opts->fs_dmask = result.uint_32;
282 		break;
283 	case Opt_fmask:
284 		opts->fs_fmask = result.uint_32;
285 		break;
286 	case Opt_allow_utime:
287 		opts->allow_utime = result.uint_32 & 0022;
288 		break;
289 	case Opt_charset:
290 		exfat_free_iocharset(sbi);
291 		opts->iocharset = param->string;
292 		param->string = NULL;
293 		break;
294 	case Opt_errors:
295 		opts->errors = result.uint_32;
296 		break;
297 	case Opt_discard:
298 		opts->discard = 1;
299 		break;
300 	case Opt_time_offset:
301 		/*
302 		 * Make the limit 24 just in case someone invents something
303 		 * unusual.
304 		 */
305 		if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
306 			return -EINVAL;
307 		opts->time_offset = result.int_32;
308 		break;
309 	case Opt_utf8:
310 	case Opt_debug:
311 	case Opt_namecase:
312 	case Opt_codepage:
313 		break;
314 	default:
315 		return -EINVAL;
316 	}
317 
318 	return 0;
319 }
320 
321 static void exfat_hash_init(struct super_block *sb)
322 {
323 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
324 	int i;
325 
326 	spin_lock_init(&sbi->inode_hash_lock);
327 	for (i = 0; i < EXFAT_HASH_SIZE; i++)
328 		INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
329 }
330 
331 static int exfat_read_root(struct inode *inode)
332 {
333 	struct super_block *sb = inode->i_sb;
334 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
335 	struct exfat_inode_info *ei = EXFAT_I(inode);
336 	struct exfat_chain cdir;
337 	int num_subdirs, num_clu = 0;
338 
339 	exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
340 	ei->entry = -1;
341 	ei->start_clu = sbi->root_dir;
342 	ei->flags = ALLOC_FAT_CHAIN;
343 	ei->type = TYPE_DIR;
344 	ei->version = 0;
345 	ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
346 	ei->hint_stat.eidx = 0;
347 	ei->hint_stat.clu = sbi->root_dir;
348 	ei->hint_femp.eidx = EXFAT_HINT_NONE;
349 
350 	exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
351 	if (exfat_count_num_clusters(sb, &cdir, &num_clu))
352 		return -EIO;
353 	i_size_write(inode, num_clu << sbi->cluster_size_bits);
354 
355 	num_subdirs = exfat_count_dir_entries(sb, &cdir);
356 	if (num_subdirs < 0)
357 		return -EIO;
358 	set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
359 
360 	inode->i_uid = sbi->options.fs_uid;
361 	inode->i_gid = sbi->options.fs_gid;
362 	inode_inc_iversion(inode);
363 	inode->i_generation = 0;
364 	inode->i_mode = exfat_make_mode(sbi, ATTR_SUBDIR, 0777);
365 	inode->i_op = &exfat_dir_inode_operations;
366 	inode->i_fop = &exfat_dir_operations;
367 
368 	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >>
369 				inode->i_blkbits;
370 	ei->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
371 	ei->i_size_aligned = i_size_read(inode);
372 	ei->i_size_ondisk = i_size_read(inode);
373 
374 	exfat_save_attr(inode, ATTR_SUBDIR);
375 	inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
376 		current_time(inode);
377 	exfat_truncate_atime(&inode->i_atime);
378 	return 0;
379 }
380 
381 static int exfat_calibrate_blocksize(struct super_block *sb, int logical_sect)
382 {
383 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
384 
385 	if (!is_power_of_2(logical_sect)) {
386 		exfat_err(sb, "bogus logical sector size %u", logical_sect);
387 		return -EIO;
388 	}
389 
390 	if (logical_sect < sb->s_blocksize) {
391 		exfat_err(sb, "logical sector size too small for device (logical sector size = %u)",
392 			  logical_sect);
393 		return -EIO;
394 	}
395 
396 	if (logical_sect > sb->s_blocksize) {
397 		brelse(sbi->boot_bh);
398 		sbi->boot_bh = NULL;
399 
400 		if (!sb_set_blocksize(sb, logical_sect)) {
401 			exfat_err(sb, "unable to set blocksize %u",
402 				  logical_sect);
403 			return -EIO;
404 		}
405 		sbi->boot_bh = sb_bread(sb, 0);
406 		if (!sbi->boot_bh) {
407 			exfat_err(sb, "unable to read boot sector (logical sector size = %lu)",
408 				  sb->s_blocksize);
409 			return -EIO;
410 		}
411 	}
412 	return 0;
413 }
414 
415 static int exfat_read_boot_sector(struct super_block *sb)
416 {
417 	struct boot_sector *p_boot;
418 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
419 
420 	/* set block size to read super block */
421 	sb_min_blocksize(sb, 512);
422 
423 	/* read boot sector */
424 	sbi->boot_bh = sb_bread(sb, 0);
425 	if (!sbi->boot_bh) {
426 		exfat_err(sb, "unable to read boot sector");
427 		return -EIO;
428 	}
429 	p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
430 
431 	/* check the validity of BOOT */
432 	if (le16_to_cpu((p_boot->signature)) != BOOT_SIGNATURE) {
433 		exfat_err(sb, "invalid boot record signature");
434 		return -EINVAL;
435 	}
436 
437 	if (memcmp(p_boot->fs_name, STR_EXFAT, BOOTSEC_FS_NAME_LEN)) {
438 		exfat_err(sb, "invalid fs_name"); /* fs_name may unprintable */
439 		return -EINVAL;
440 	}
441 
442 	/*
443 	 * must_be_zero field must be filled with zero to prevent mounting
444 	 * from FAT volume.
445 	 */
446 	if (memchr_inv(p_boot->must_be_zero, 0, sizeof(p_boot->must_be_zero)))
447 		return -EINVAL;
448 
449 	if (p_boot->num_fats != 1 && p_boot->num_fats != 2) {
450 		exfat_err(sb, "bogus number of FAT structure");
451 		return -EINVAL;
452 	}
453 
454 	/*
455 	 * sect_size_bits could be at least 9 and at most 12.
456 	 */
457 	if (p_boot->sect_size_bits < EXFAT_MIN_SECT_SIZE_BITS ||
458 	    p_boot->sect_size_bits > EXFAT_MAX_SECT_SIZE_BITS) {
459 		exfat_err(sb, "bogus sector size bits : %u\n",
460 				p_boot->sect_size_bits);
461 		return -EINVAL;
462 	}
463 
464 	/*
465 	 * sect_per_clus_bits could be at least 0 and at most 25 - sect_size_bits.
466 	 */
467 	if (p_boot->sect_per_clus_bits > EXFAT_MAX_SECT_PER_CLUS_BITS(p_boot)) {
468 		exfat_err(sb, "bogus sectors bits per cluster : %u\n",
469 				p_boot->sect_per_clus_bits);
470 		return -EINVAL;
471 	}
472 
473 	sbi->sect_per_clus = 1 << p_boot->sect_per_clus_bits;
474 	sbi->sect_per_clus_bits = p_boot->sect_per_clus_bits;
475 	sbi->cluster_size_bits = p_boot->sect_per_clus_bits +
476 		p_boot->sect_size_bits;
477 	sbi->cluster_size = 1 << sbi->cluster_size_bits;
478 	sbi->num_FAT_sectors = le32_to_cpu(p_boot->fat_length);
479 	sbi->FAT1_start_sector = le32_to_cpu(p_boot->fat_offset);
480 	sbi->FAT2_start_sector = le32_to_cpu(p_boot->fat_offset);
481 	if (p_boot->num_fats == 2)
482 		sbi->FAT2_start_sector += sbi->num_FAT_sectors;
483 	sbi->data_start_sector = le32_to_cpu(p_boot->clu_offset);
484 	sbi->num_sectors = le64_to_cpu(p_boot->vol_length);
485 	/* because the cluster index starts with 2 */
486 	sbi->num_clusters = le32_to_cpu(p_boot->clu_count) +
487 		EXFAT_RESERVED_CLUSTERS;
488 
489 	sbi->root_dir = le32_to_cpu(p_boot->root_cluster);
490 	sbi->dentries_per_clu = 1 <<
491 		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
492 
493 	sbi->vol_flags = le16_to_cpu(p_boot->vol_flags);
494 	sbi->vol_flags_persistent = sbi->vol_flags & (VOLUME_DIRTY | MEDIA_FAILURE);
495 	sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
496 	sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED;
497 
498 	/* check consistencies */
499 	if ((u64)sbi->num_FAT_sectors << p_boot->sect_size_bits <
500 	    (u64)sbi->num_clusters * 4) {
501 		exfat_err(sb, "bogus fat length");
502 		return -EINVAL;
503 	}
504 
505 	if (sbi->data_start_sector <
506 	    (u64)sbi->FAT1_start_sector +
507 	    (u64)sbi->num_FAT_sectors * p_boot->num_fats) {
508 		exfat_err(sb, "bogus data start sector");
509 		return -EINVAL;
510 	}
511 
512 	if (sbi->vol_flags & VOLUME_DIRTY)
513 		exfat_warn(sb, "Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
514 	if (sbi->vol_flags & MEDIA_FAILURE)
515 		exfat_warn(sb, "Medium has reported failures. Some data may be lost.");
516 
517 	/* exFAT file size is limited by a disk volume size */
518 	sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) <<
519 		sbi->cluster_size_bits;
520 
521 	/* check logical sector size */
522 	if (exfat_calibrate_blocksize(sb, 1 << p_boot->sect_size_bits))
523 		return -EIO;
524 
525 	return 0;
526 }
527 
528 static int exfat_verify_boot_region(struct super_block *sb)
529 {
530 	struct buffer_head *bh = NULL;
531 	u32 chksum = 0;
532 	__le32 *p_sig, *p_chksum;
533 	int sn, i;
534 
535 	/* read boot sector sub-regions */
536 	for (sn = 0; sn < 11; sn++) {
537 		bh = sb_bread(sb, sn);
538 		if (!bh)
539 			return -EIO;
540 
541 		if (sn != 0 && sn <= 8) {
542 			/* extended boot sector sub-regions */
543 			p_sig = (__le32 *)&bh->b_data[sb->s_blocksize - 4];
544 			if (le32_to_cpu(*p_sig) != EXBOOT_SIGNATURE)
545 				exfat_warn(sb, "Invalid exboot-signature(sector = %d): 0x%08x",
546 					   sn, le32_to_cpu(*p_sig));
547 		}
548 
549 		chksum = exfat_calc_chksum32(bh->b_data, sb->s_blocksize,
550 			chksum, sn ? CS_DEFAULT : CS_BOOT_SECTOR);
551 		brelse(bh);
552 	}
553 
554 	/* boot checksum sub-regions */
555 	bh = sb_bread(sb, sn);
556 	if (!bh)
557 		return -EIO;
558 
559 	for (i = 0; i < sb->s_blocksize; i += sizeof(u32)) {
560 		p_chksum = (__le32 *)&bh->b_data[i];
561 		if (le32_to_cpu(*p_chksum) != chksum) {
562 			exfat_err(sb, "Invalid boot checksum (boot checksum : 0x%08x, checksum : 0x%08x)",
563 				  le32_to_cpu(*p_chksum), chksum);
564 			brelse(bh);
565 			return -EINVAL;
566 		}
567 	}
568 	brelse(bh);
569 	return 0;
570 }
571 
572 /* mount the file system volume */
573 static int __exfat_fill_super(struct super_block *sb)
574 {
575 	int ret;
576 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
577 
578 	ret = exfat_read_boot_sector(sb);
579 	if (ret) {
580 		exfat_err(sb, "failed to read boot sector");
581 		goto free_bh;
582 	}
583 
584 	ret = exfat_verify_boot_region(sb);
585 	if (ret) {
586 		exfat_err(sb, "invalid boot region");
587 		goto free_bh;
588 	}
589 
590 	ret = exfat_create_upcase_table(sb);
591 	if (ret) {
592 		exfat_err(sb, "failed to load upcase table");
593 		goto free_bh;
594 	}
595 
596 	ret = exfat_load_bitmap(sb);
597 	if (ret) {
598 		exfat_err(sb, "failed to load alloc-bitmap");
599 		goto free_upcase_table;
600 	}
601 
602 	ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
603 	if (ret) {
604 		exfat_err(sb, "failed to scan clusters");
605 		goto free_alloc_bitmap;
606 	}
607 
608 	return 0;
609 
610 free_alloc_bitmap:
611 	exfat_free_bitmap(sbi);
612 free_upcase_table:
613 	exfat_free_upcase_table(sbi);
614 free_bh:
615 	brelse(sbi->boot_bh);
616 	return ret;
617 }
618 
619 static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
620 {
621 	struct exfat_sb_info *sbi = sb->s_fs_info;
622 	struct exfat_mount_options *opts = &sbi->options;
623 	struct inode *root_inode;
624 	int err;
625 
626 	if (opts->allow_utime == (unsigned short)-1)
627 		opts->allow_utime = ~opts->fs_dmask & 0022;
628 
629 	if (opts->discard) {
630 		struct request_queue *q = bdev_get_queue(sb->s_bdev);
631 
632 		if (!blk_queue_discard(q)) {
633 			exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
634 			opts->discard = 0;
635 		}
636 	}
637 
638 	sb->s_flags |= SB_NODIRATIME;
639 	sb->s_magic = EXFAT_SUPER_MAGIC;
640 	sb->s_op = &exfat_sops;
641 
642 	sb->s_time_gran = 10 * NSEC_PER_MSEC;
643 	sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
644 	sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
645 
646 	err = __exfat_fill_super(sb);
647 	if (err) {
648 		exfat_err(sb, "failed to recognize exfat type");
649 		goto check_nls_io;
650 	}
651 
652 	/* set up enough so that it can read an inode */
653 	exfat_hash_init(sb);
654 
655 	if (!strcmp(sbi->options.iocharset, "utf8"))
656 		opts->utf8 = 1;
657 	else {
658 		sbi->nls_io = load_nls(sbi->options.iocharset);
659 		if (!sbi->nls_io) {
660 			exfat_err(sb, "IO charset %s not found",
661 				  sbi->options.iocharset);
662 			err = -EINVAL;
663 			goto free_table;
664 		}
665 	}
666 
667 	if (sbi->options.utf8)
668 		sb->s_d_op = &exfat_utf8_dentry_ops;
669 	else
670 		sb->s_d_op = &exfat_dentry_ops;
671 
672 	root_inode = new_inode(sb);
673 	if (!root_inode) {
674 		exfat_err(sb, "failed to allocate root inode");
675 		err = -ENOMEM;
676 		goto free_table;
677 	}
678 
679 	root_inode->i_ino = EXFAT_ROOT_INO;
680 	inode_set_iversion(root_inode, 1);
681 	err = exfat_read_root(root_inode);
682 	if (err) {
683 		exfat_err(sb, "failed to initialize root inode");
684 		goto put_inode;
685 	}
686 
687 	exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
688 	insert_inode_hash(root_inode);
689 
690 	sb->s_root = d_make_root(root_inode);
691 	if (!sb->s_root) {
692 		exfat_err(sb, "failed to get the root dentry");
693 		err = -ENOMEM;
694 		goto free_table;
695 	}
696 
697 	return 0;
698 
699 put_inode:
700 	iput(root_inode);
701 	sb->s_root = NULL;
702 
703 free_table:
704 	exfat_free_upcase_table(sbi);
705 	exfat_free_bitmap(sbi);
706 	brelse(sbi->boot_bh);
707 
708 check_nls_io:
709 	unload_nls(sbi->nls_io);
710 	exfat_free_iocharset(sbi);
711 	sb->s_fs_info = NULL;
712 	kfree(sbi);
713 	return err;
714 }
715 
716 static int exfat_get_tree(struct fs_context *fc)
717 {
718 	return get_tree_bdev(fc, exfat_fill_super);
719 }
720 
721 static void exfat_free(struct fs_context *fc)
722 {
723 	struct exfat_sb_info *sbi = fc->s_fs_info;
724 
725 	if (sbi) {
726 		exfat_free_iocharset(sbi);
727 		kfree(sbi);
728 	}
729 }
730 
731 static int exfat_reconfigure(struct fs_context *fc)
732 {
733 	fc->sb_flags |= SB_NODIRATIME;
734 
735 	/* volume flag will be updated in exfat_sync_fs */
736 	sync_filesystem(fc->root->d_sb);
737 	return 0;
738 }
739 
740 static const struct fs_context_operations exfat_context_ops = {
741 	.parse_param	= exfat_parse_param,
742 	.get_tree	= exfat_get_tree,
743 	.free		= exfat_free,
744 	.reconfigure	= exfat_reconfigure,
745 };
746 
747 static int exfat_init_fs_context(struct fs_context *fc)
748 {
749 	struct exfat_sb_info *sbi;
750 
751 	sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
752 	if (!sbi)
753 		return -ENOMEM;
754 
755 	mutex_init(&sbi->s_lock);
756 	mutex_init(&sbi->bitmap_lock);
757 	ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
758 			DEFAULT_RATELIMIT_BURST);
759 
760 	sbi->options.fs_uid = current_uid();
761 	sbi->options.fs_gid = current_gid();
762 	sbi->options.fs_fmask = current->fs->umask;
763 	sbi->options.fs_dmask = current->fs->umask;
764 	sbi->options.allow_utime = -1;
765 	sbi->options.iocharset = exfat_default_iocharset;
766 	sbi->options.errors = EXFAT_ERRORS_RO;
767 
768 	fc->s_fs_info = sbi;
769 	fc->ops = &exfat_context_ops;
770 	return 0;
771 }
772 
773 static struct file_system_type exfat_fs_type = {
774 	.owner			= THIS_MODULE,
775 	.name			= "exfat",
776 	.init_fs_context	= exfat_init_fs_context,
777 	.parameters		= exfat_parameters,
778 	.kill_sb		= kill_block_super,
779 	.fs_flags		= FS_REQUIRES_DEV,
780 };
781 
782 static void exfat_inode_init_once(void *foo)
783 {
784 	struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
785 
786 	spin_lock_init(&ei->cache_lru_lock);
787 	ei->nr_caches = 0;
788 	ei->cache_valid_id = EXFAT_CACHE_VALID + 1;
789 	INIT_LIST_HEAD(&ei->cache_lru);
790 	INIT_HLIST_NODE(&ei->i_hash_fat);
791 	inode_init_once(&ei->vfs_inode);
792 }
793 
794 static int __init init_exfat_fs(void)
795 {
796 	int err;
797 
798 	err = exfat_cache_init();
799 	if (err)
800 		return err;
801 
802 	exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
803 			sizeof(struct exfat_inode_info),
804 			0, SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
805 			exfat_inode_init_once);
806 	if (!exfat_inode_cachep) {
807 		err = -ENOMEM;
808 		goto shutdown_cache;
809 	}
810 
811 	err = register_filesystem(&exfat_fs_type);
812 	if (err)
813 		goto destroy_cache;
814 
815 	return 0;
816 
817 destroy_cache:
818 	kmem_cache_destroy(exfat_inode_cachep);
819 shutdown_cache:
820 	exfat_cache_shutdown();
821 	return err;
822 }
823 
824 static void __exit exit_exfat_fs(void)
825 {
826 	/*
827 	 * Make sure all delayed rcu free inodes are flushed before we
828 	 * destroy cache.
829 	 */
830 	rcu_barrier();
831 	kmem_cache_destroy(exfat_inode_cachep);
832 	unregister_filesystem(&exfat_fs_type);
833 	exfat_cache_shutdown();
834 }
835 
836 module_init(init_exfat_fs);
837 module_exit(exit_exfat_fs);
838 
839 MODULE_ALIAS_FS("exfat");
840 MODULE_LICENSE("GPL");
841 MODULE_DESCRIPTION("exFAT filesystem support");
842 MODULE_AUTHOR("Samsung Electronics Co., Ltd.");
843