xref: /linux/fs/exfat/super.c (revision d195c39052d1da278a00a6744ce59c383b67b191)
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 
21 #include "exfat_raw.h"
22 #include "exfat_fs.h"
23 
24 static char exfat_default_iocharset[] = CONFIG_EXFAT_DEFAULT_IOCHARSET;
25 static struct kmem_cache *exfat_inode_cachep;
26 
27 static void exfat_free_iocharset(struct exfat_sb_info *sbi)
28 {
29 	if (sbi->options.iocharset != exfat_default_iocharset)
30 		kfree(sbi->options.iocharset);
31 }
32 
33 static void exfat_delayed_free(struct rcu_head *p)
34 {
35 	struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu);
36 
37 	unload_nls(sbi->nls_io);
38 	exfat_free_iocharset(sbi);
39 	exfat_free_upcase_table(sbi);
40 	kfree(sbi);
41 }
42 
43 static void exfat_put_super(struct super_block *sb)
44 {
45 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
46 
47 	mutex_lock(&sbi->s_lock);
48 	if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state))
49 		sync_blockdev(sb->s_bdev);
50 	exfat_set_vol_flags(sb, VOL_CLEAN);
51 	exfat_free_bitmap(sbi);
52 	mutex_unlock(&sbi->s_lock);
53 
54 	call_rcu(&sbi->rcu, exfat_delayed_free);
55 }
56 
57 static int exfat_sync_fs(struct super_block *sb, int wait)
58 {
59 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
60 	int err = 0;
61 
62 	/* If there are some dirty buffers in the bdev inode */
63 	mutex_lock(&sbi->s_lock);
64 	if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state)) {
65 		sync_blockdev(sb->s_bdev);
66 		if (exfat_set_vol_flags(sb, VOL_CLEAN))
67 			err = -EIO;
68 	}
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.val[0] = (unsigned int)id;
94 	buf->f_fsid.val[1] = (unsigned int)(id >> 32);
95 	/* Unicode utf16 255 characters */
96 	buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE;
97 	return 0;
98 }
99 
100 int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)
101 {
102 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
103 	struct pbr64 *bpb;
104 	bool sync = 0;
105 
106 	/* flags are not changed */
107 	if (sbi->vol_flag == new_flag)
108 		return 0;
109 
110 	sbi->vol_flag = new_flag;
111 
112 	/* skip updating volume dirty flag,
113 	 * if this volume has been mounted with read-only
114 	 */
115 	if (sb_rdonly(sb))
116 		return 0;
117 
118 	if (!sbi->pbr_bh) {
119 		sbi->pbr_bh = sb_bread(sb, 0);
120 		if (!sbi->pbr_bh) {
121 			exfat_msg(sb, KERN_ERR, "failed to read boot sector");
122 			return -ENOMEM;
123 		}
124 	}
125 
126 	bpb = (struct pbr64 *)sbi->pbr_bh->b_data;
127 	bpb->bsx.vol_flags = cpu_to_le16(new_flag);
128 
129 	if (new_flag == VOL_DIRTY && !buffer_dirty(sbi->pbr_bh))
130 		sync = true;
131 	else
132 		sync = false;
133 
134 	set_buffer_uptodate(sbi->pbr_bh);
135 	mark_buffer_dirty(sbi->pbr_bh);
136 
137 	if (sync)
138 		sync_dirty_buffer(sbi->pbr_bh);
139 	return 0;
140 }
141 
142 static int exfat_show_options(struct seq_file *m, struct dentry *root)
143 {
144 	struct super_block *sb = root->d_sb;
145 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
146 	struct exfat_mount_options *opts = &sbi->options;
147 
148 	/* Show partition info */
149 	if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
150 		seq_printf(m, ",uid=%u",
151 				from_kuid_munged(&init_user_ns, opts->fs_uid));
152 	if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
153 		seq_printf(m, ",gid=%u",
154 				from_kgid_munged(&init_user_ns, opts->fs_gid));
155 	seq_printf(m, ",fmask=%04o,dmask=%04o", opts->fs_fmask, opts->fs_dmask);
156 	if (opts->allow_utime)
157 		seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
158 	if (opts->utf8)
159 		seq_puts(m, ",iocharset=utf8");
160 	else if (sbi->nls_io)
161 		seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
162 	seq_printf(m, ",bps=%ld", sb->s_blocksize);
163 	if (opts->errors == EXFAT_ERRORS_CONT)
164 		seq_puts(m, ",errors=continue");
165 	else if (opts->errors == EXFAT_ERRORS_PANIC)
166 		seq_puts(m, ",errors=panic");
167 	else
168 		seq_puts(m, ",errors=remount-ro");
169 	if (opts->discard)
170 		seq_puts(m, ",discard");
171 	if (opts->time_offset)
172 		seq_printf(m, ",time_offset=%d", opts->time_offset);
173 	return 0;
174 }
175 
176 static struct inode *exfat_alloc_inode(struct super_block *sb)
177 {
178 	struct exfat_inode_info *ei;
179 
180 	ei = kmem_cache_alloc(exfat_inode_cachep, GFP_NOFS);
181 	if (!ei)
182 		return NULL;
183 
184 	init_rwsem(&ei->truncate_lock);
185 	return &ei->vfs_inode;
186 }
187 
188 static void exfat_free_inode(struct inode *inode)
189 {
190 	kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
191 }
192 
193 static const struct super_operations exfat_sops = {
194 	.alloc_inode	= exfat_alloc_inode,
195 	.free_inode	= exfat_free_inode,
196 	.write_inode	= exfat_write_inode,
197 	.evict_inode	= exfat_evict_inode,
198 	.put_super	= exfat_put_super,
199 	.sync_fs	= exfat_sync_fs,
200 	.statfs		= exfat_statfs,
201 	.show_options	= exfat_show_options,
202 };
203 
204 enum {
205 	Opt_uid,
206 	Opt_gid,
207 	Opt_umask,
208 	Opt_dmask,
209 	Opt_fmask,
210 	Opt_allow_utime,
211 	Opt_charset,
212 	Opt_errors,
213 	Opt_discard,
214 	Opt_time_offset,
215 };
216 
217 static const struct constant_table exfat_param_enums[] = {
218 	{ "continue",		EXFAT_ERRORS_CONT },
219 	{ "panic",		EXFAT_ERRORS_PANIC },
220 	{ "remount-ro",		EXFAT_ERRORS_RO },
221 	{}
222 };
223 
224 static const struct fs_parameter_spec exfat_parameters[] = {
225 	fsparam_u32("uid",			Opt_uid),
226 	fsparam_u32("gid",			Opt_gid),
227 	fsparam_u32oct("umask",			Opt_umask),
228 	fsparam_u32oct("dmask",			Opt_dmask),
229 	fsparam_u32oct("fmask",			Opt_fmask),
230 	fsparam_u32oct("allow_utime",		Opt_allow_utime),
231 	fsparam_string("iocharset",		Opt_charset),
232 	fsparam_enum("errors",			Opt_errors, exfat_param_enums),
233 	fsparam_flag("discard",			Opt_discard),
234 	fsparam_s32("time_offset",		Opt_time_offset),
235 	{}
236 };
237 
238 static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
239 {
240 	struct exfat_sb_info *sbi = fc->s_fs_info;
241 	struct exfat_mount_options *opts = &sbi->options;
242 	struct fs_parse_result result;
243 	int opt;
244 
245 	opt = fs_parse(fc, exfat_parameters, param, &result);
246 	if (opt < 0)
247 		return opt;
248 
249 	switch (opt) {
250 	case Opt_uid:
251 		opts->fs_uid = make_kuid(current_user_ns(), result.uint_32);
252 		break;
253 	case Opt_gid:
254 		opts->fs_gid = make_kgid(current_user_ns(), result.uint_32);
255 		break;
256 	case Opt_umask:
257 		opts->fs_fmask = result.uint_32;
258 		opts->fs_dmask = result.uint_32;
259 		break;
260 	case Opt_dmask:
261 		opts->fs_dmask = result.uint_32;
262 		break;
263 	case Opt_fmask:
264 		opts->fs_fmask = result.uint_32;
265 		break;
266 	case Opt_allow_utime:
267 		opts->allow_utime = result.uint_32 & 0022;
268 		break;
269 	case Opt_charset:
270 		exfat_free_iocharset(sbi);
271 		opts->iocharset = kstrdup(param->string, GFP_KERNEL);
272 		if (!opts->iocharset)
273 			return -ENOMEM;
274 		break;
275 	case Opt_errors:
276 		opts->errors = result.uint_32;
277 		break;
278 	case Opt_discard:
279 		opts->discard = 1;
280 		break;
281 	case Opt_time_offset:
282 		/*
283 		 * Make the limit 24 just in case someone invents something
284 		 * unusual.
285 		 */
286 		if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
287 			return -EINVAL;
288 		opts->time_offset = result.int_32;
289 		break;
290 	default:
291 		return -EINVAL;
292 	}
293 
294 	return 0;
295 }
296 
297 static void exfat_hash_init(struct super_block *sb)
298 {
299 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
300 	int i;
301 
302 	spin_lock_init(&sbi->inode_hash_lock);
303 	for (i = 0; i < EXFAT_HASH_SIZE; i++)
304 		INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
305 }
306 
307 static int exfat_read_root(struct inode *inode)
308 {
309 	struct super_block *sb = inode->i_sb;
310 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
311 	struct exfat_inode_info *ei = EXFAT_I(inode);
312 	struct exfat_chain cdir;
313 	int num_subdirs, num_clu = 0;
314 
315 	exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
316 	ei->entry = -1;
317 	ei->start_clu = sbi->root_dir;
318 	ei->flags = ALLOC_FAT_CHAIN;
319 	ei->type = TYPE_DIR;
320 	ei->version = 0;
321 	ei->rwoffset = 0;
322 	ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
323 	ei->hint_stat.eidx = 0;
324 	ei->hint_stat.clu = sbi->root_dir;
325 	ei->hint_femp.eidx = EXFAT_HINT_NONE;
326 
327 	exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
328 	if (exfat_count_num_clusters(sb, &cdir, &num_clu))
329 		return -EIO;
330 	i_size_write(inode, num_clu << sbi->cluster_size_bits);
331 
332 	num_subdirs = exfat_count_dir_entries(sb, &cdir);
333 	if (num_subdirs < 0)
334 		return -EIO;
335 	set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
336 
337 	inode->i_uid = sbi->options.fs_uid;
338 	inode->i_gid = sbi->options.fs_gid;
339 	inode_inc_iversion(inode);
340 	inode->i_generation = 0;
341 	inode->i_mode = exfat_make_mode(sbi, ATTR_SUBDIR, 0777);
342 	inode->i_op = &exfat_dir_inode_operations;
343 	inode->i_fop = &exfat_dir_operations;
344 
345 	inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1))
346 			& ~(sbi->cluster_size - 1)) >> inode->i_blkbits;
347 	EXFAT_I(inode)->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
348 	EXFAT_I(inode)->i_size_aligned = i_size_read(inode);
349 	EXFAT_I(inode)->i_size_ondisk = i_size_read(inode);
350 
351 	exfat_save_attr(inode, ATTR_SUBDIR);
352 	inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
353 		current_time(inode);
354 	exfat_cache_init_inode(inode);
355 	return 0;
356 }
357 
358 static struct pbr *exfat_read_pbr_with_logical_sector(struct super_block *sb,
359 		struct buffer_head **prev_bh)
360 {
361 	struct pbr *p_pbr = (struct pbr *) (*prev_bh)->b_data;
362 	unsigned short logical_sect = 0;
363 
364 	logical_sect = 1 << p_pbr->bsx.f64.sect_size_bits;
365 
366 	if (!is_power_of_2(logical_sect) ||
367 	    logical_sect < 512 || logical_sect > 4096) {
368 		exfat_msg(sb, KERN_ERR, "bogus logical sector size %u",
369 				logical_sect);
370 		return NULL;
371 	}
372 
373 	if (logical_sect < sb->s_blocksize) {
374 		exfat_msg(sb, KERN_ERR,
375 			"logical sector size too small for device (logical sector size = %u)",
376 			logical_sect);
377 		return NULL;
378 	}
379 
380 	if (logical_sect > sb->s_blocksize) {
381 		struct buffer_head *bh = NULL;
382 
383 		__brelse(*prev_bh);
384 		*prev_bh = NULL;
385 
386 		if (!sb_set_blocksize(sb, logical_sect)) {
387 			exfat_msg(sb, KERN_ERR,
388 				"unable to set blocksize %u", logical_sect);
389 			return NULL;
390 		}
391 		bh = sb_bread(sb, 0);
392 		if (!bh) {
393 			exfat_msg(sb, KERN_ERR,
394 				"unable to read boot sector (logical sector size = %lu)",
395 				sb->s_blocksize);
396 			return NULL;
397 		}
398 
399 		*prev_bh = bh;
400 		p_pbr = (struct pbr *) bh->b_data;
401 	}
402 	return p_pbr;
403 }
404 
405 /* mount the file system volume */
406 static int __exfat_fill_super(struct super_block *sb)
407 {
408 	int ret;
409 	struct pbr *p_pbr;
410 	struct pbr64 *p_bpb;
411 	struct buffer_head *bh;
412 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
413 
414 	/* set block size to read super block */
415 	sb_min_blocksize(sb, 512);
416 
417 	/* read boot sector */
418 	bh = sb_bread(sb, 0);
419 	if (!bh) {
420 		exfat_msg(sb, KERN_ERR, "unable to read boot sector");
421 		return -EIO;
422 	}
423 
424 	/* PRB is read */
425 	p_pbr = (struct pbr *)bh->b_data;
426 
427 	/* check the validity of PBR */
428 	if (le16_to_cpu((p_pbr->signature)) != PBR_SIGNATURE) {
429 		exfat_msg(sb, KERN_ERR, "invalid boot record signature");
430 		ret = -EINVAL;
431 		goto free_bh;
432 	}
433 
434 
435 	/* check logical sector size */
436 	p_pbr = exfat_read_pbr_with_logical_sector(sb, &bh);
437 	if (!p_pbr) {
438 		ret = -EIO;
439 		goto free_bh;
440 	}
441 
442 	/*
443 	 * res_zero field must be filled with zero to prevent mounting
444 	 * from FAT volume.
445 	 */
446 	if (memchr_inv(p_pbr->bpb.f64.res_zero, 0,
447 			sizeof(p_pbr->bpb.f64.res_zero))) {
448 		ret = -EINVAL;
449 		goto free_bh;
450 	}
451 
452 	p_bpb = (struct pbr64 *)p_pbr;
453 	if (!p_bpb->bsx.num_fats) {
454 		exfat_msg(sb, KERN_ERR, "bogus number of FAT structure");
455 		ret = -EINVAL;
456 		goto free_bh;
457 	}
458 
459 	sbi->sect_per_clus = 1 << p_bpb->bsx.sect_per_clus_bits;
460 	sbi->sect_per_clus_bits = p_bpb->bsx.sect_per_clus_bits;
461 	sbi->cluster_size_bits = sbi->sect_per_clus_bits + sb->s_blocksize_bits;
462 	sbi->cluster_size = 1 << sbi->cluster_size_bits;
463 	sbi->num_FAT_sectors = le32_to_cpu(p_bpb->bsx.fat_length);
464 	sbi->FAT1_start_sector = le32_to_cpu(p_bpb->bsx.fat_offset);
465 	sbi->FAT2_start_sector = p_bpb->bsx.num_fats == 1 ?
466 		sbi->FAT1_start_sector :
467 			sbi->FAT1_start_sector + sbi->num_FAT_sectors;
468 	sbi->data_start_sector = le32_to_cpu(p_bpb->bsx.clu_offset);
469 	sbi->num_sectors = le64_to_cpu(p_bpb->bsx.vol_length);
470 	/* because the cluster index starts with 2 */
471 	sbi->num_clusters = le32_to_cpu(p_bpb->bsx.clu_count) +
472 		EXFAT_RESERVED_CLUSTERS;
473 
474 	sbi->root_dir = le32_to_cpu(p_bpb->bsx.root_cluster);
475 	sbi->dentries_per_clu = 1 <<
476 		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
477 
478 	sbi->vol_flag = le16_to_cpu(p_bpb->bsx.vol_flags);
479 	sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
480 	sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED;
481 
482 	if (le16_to_cpu(p_bpb->bsx.vol_flags) & VOL_DIRTY) {
483 		sbi->vol_flag |= VOL_DIRTY;
484 		exfat_msg(sb, KERN_WARNING,
485 			"Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
486 	}
487 
488 	/* exFAT file size is limited by a disk volume size */
489 	sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) <<
490 		sbi->cluster_size_bits;
491 
492 	ret = exfat_create_upcase_table(sb);
493 	if (ret) {
494 		exfat_msg(sb, KERN_ERR, "failed to load upcase table");
495 		goto free_bh;
496 	}
497 
498 	ret = exfat_load_bitmap(sb);
499 	if (ret) {
500 		exfat_msg(sb, KERN_ERR, "failed to load alloc-bitmap");
501 		goto free_upcase_table;
502 	}
503 
504 	ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
505 	if (ret) {
506 		exfat_msg(sb, KERN_ERR, "failed to scan clusters");
507 		goto free_alloc_bitmap;
508 	}
509 
510 	return 0;
511 
512 free_alloc_bitmap:
513 	exfat_free_bitmap(sbi);
514 free_upcase_table:
515 	exfat_free_upcase_table(sbi);
516 free_bh:
517 	brelse(bh);
518 	return ret;
519 }
520 
521 static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
522 {
523 	struct exfat_sb_info *sbi = sb->s_fs_info;
524 	struct exfat_mount_options *opts = &sbi->options;
525 	struct inode *root_inode;
526 	int err;
527 
528 	if (opts->allow_utime == (unsigned short)-1)
529 		opts->allow_utime = ~opts->fs_dmask & 0022;
530 
531 	if (opts->discard) {
532 		struct request_queue *q = bdev_get_queue(sb->s_bdev);
533 
534 		if (!blk_queue_discard(q))
535 			exfat_msg(sb, KERN_WARNING,
536 				"mounting with \"discard\" option, but the device does not support discard");
537 		opts->discard = 0;
538 	}
539 
540 	sb->s_flags |= SB_NODIRATIME;
541 	sb->s_magic = EXFAT_SUPER_MAGIC;
542 	sb->s_op = &exfat_sops;
543 
544 	sb->s_time_gran = 1;
545 	sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
546 	sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
547 
548 	err = __exfat_fill_super(sb);
549 	if (err) {
550 		exfat_msg(sb, KERN_ERR, "failed to recognize exfat type");
551 		goto check_nls_io;
552 	}
553 
554 	/* set up enough so that it can read an inode */
555 	exfat_hash_init(sb);
556 
557 	if (!strcmp(sbi->options.iocharset, "utf8"))
558 		opts->utf8 = 1;
559 	else {
560 		sbi->nls_io = load_nls(sbi->options.iocharset);
561 		if (!sbi->nls_io) {
562 			exfat_msg(sb, KERN_ERR, "IO charset %s not found",
563 					sbi->options.iocharset);
564 			err = -EINVAL;
565 			goto free_table;
566 		}
567 	}
568 
569 	if (sbi->options.utf8)
570 		sb->s_d_op = &exfat_utf8_dentry_ops;
571 	else
572 		sb->s_d_op = &exfat_dentry_ops;
573 
574 	root_inode = new_inode(sb);
575 	if (!root_inode) {
576 		exfat_msg(sb, KERN_ERR, "failed to allocate root inode.");
577 		err = -ENOMEM;
578 		goto free_table;
579 	}
580 
581 	root_inode->i_ino = EXFAT_ROOT_INO;
582 	inode_set_iversion(root_inode, 1);
583 	err = exfat_read_root(root_inode);
584 	if (err) {
585 		exfat_msg(sb, KERN_ERR, "failed to initialize root inode.");
586 		goto put_inode;
587 	}
588 
589 	exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
590 	insert_inode_hash(root_inode);
591 
592 	sb->s_root = d_make_root(root_inode);
593 	if (!sb->s_root) {
594 		exfat_msg(sb, KERN_ERR, "failed to get the root dentry");
595 		err = -ENOMEM;
596 		goto put_inode;
597 	}
598 
599 	return 0;
600 
601 put_inode:
602 	iput(root_inode);
603 	sb->s_root = NULL;
604 
605 free_table:
606 	exfat_free_upcase_table(sbi);
607 	exfat_free_bitmap(sbi);
608 
609 check_nls_io:
610 	unload_nls(sbi->nls_io);
611 	exfat_free_iocharset(sbi);
612 	sb->s_fs_info = NULL;
613 	kfree(sbi);
614 	return err;
615 }
616 
617 static int exfat_get_tree(struct fs_context *fc)
618 {
619 	return get_tree_bdev(fc, exfat_fill_super);
620 }
621 
622 static void exfat_free(struct fs_context *fc)
623 {
624 	kfree(fc->s_fs_info);
625 }
626 
627 static const struct fs_context_operations exfat_context_ops = {
628 	.parse_param	= exfat_parse_param,
629 	.get_tree	= exfat_get_tree,
630 	.free		= exfat_free,
631 };
632 
633 static int exfat_init_fs_context(struct fs_context *fc)
634 {
635 	struct exfat_sb_info *sbi;
636 
637 	sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
638 	if (!sbi)
639 		return -ENOMEM;
640 
641 	mutex_init(&sbi->s_lock);
642 	ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
643 			DEFAULT_RATELIMIT_BURST);
644 
645 	sbi->options.fs_uid = current_uid();
646 	sbi->options.fs_gid = current_gid();
647 	sbi->options.fs_fmask = current->fs->umask;
648 	sbi->options.fs_dmask = current->fs->umask;
649 	sbi->options.allow_utime = -1;
650 	sbi->options.iocharset = exfat_default_iocharset;
651 	sbi->options.errors = EXFAT_ERRORS_RO;
652 
653 	fc->s_fs_info = sbi;
654 	fc->ops = &exfat_context_ops;
655 	return 0;
656 }
657 
658 static struct file_system_type exfat_fs_type = {
659 	.owner			= THIS_MODULE,
660 	.name			= "exfat",
661 	.init_fs_context	= exfat_init_fs_context,
662 	.parameters		= exfat_parameters,
663 	.kill_sb		= kill_block_super,
664 	.fs_flags		= FS_REQUIRES_DEV,
665 };
666 
667 static void exfat_inode_init_once(void *foo)
668 {
669 	struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
670 
671 	INIT_HLIST_NODE(&ei->i_hash_fat);
672 	inode_init_once(&ei->vfs_inode);
673 }
674 
675 static int __init init_exfat_fs(void)
676 {
677 	int err;
678 
679 	err = exfat_cache_init();
680 	if (err)
681 		return err;
682 
683 	exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
684 			sizeof(struct exfat_inode_info),
685 			0, SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
686 			exfat_inode_init_once);
687 	if (!exfat_inode_cachep) {
688 		err = -ENOMEM;
689 		goto shutdown_cache;
690 	}
691 
692 	err = register_filesystem(&exfat_fs_type);
693 	if (err)
694 		goto destroy_cache;
695 
696 	return 0;
697 
698 destroy_cache:
699 	kmem_cache_destroy(exfat_inode_cachep);
700 shutdown_cache:
701 	exfat_cache_shutdown();
702 	return err;
703 }
704 
705 static void __exit exit_exfat_fs(void)
706 {
707 	/*
708 	 * Make sure all delayed rcu free inodes are flushed before we
709 	 * destroy cache.
710 	 */
711 	rcu_barrier();
712 	kmem_cache_destroy(exfat_inode_cachep);
713 	unregister_filesystem(&exfat_fs_type);
714 	exfat_cache_shutdown();
715 }
716 
717 module_init(init_exfat_fs);
718 module_exit(exit_exfat_fs);
719 
720 MODULE_LICENSE("GPL");
721 MODULE_DESCRIPTION("exFAT filesystem support");
722 MODULE_AUTHOR("Samsung Electronics Co., Ltd.");
723