xref: /openbmc/linux/fs/exfat/super.c (revision 37744fee)
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 	brelse(sbi->pbr_bh);
53 	mutex_unlock(&sbi->s_lock);
54 
55 	call_rcu(&sbi->rcu, exfat_delayed_free);
56 }
57 
58 static int exfat_sync_fs(struct super_block *sb, int wait)
59 {
60 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
61 	int err = 0;
62 
63 	/* If there are some dirty buffers in the bdev inode */
64 	mutex_lock(&sbi->s_lock);
65 	if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state)) {
66 		sync_blockdev(sb->s_bdev);
67 		if (exfat_set_vol_flags(sb, VOL_CLEAN))
68 			err = -EIO;
69 	}
70 	mutex_unlock(&sbi->s_lock);
71 	return err;
72 }
73 
74 static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
75 {
76 	struct super_block *sb = dentry->d_sb;
77 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
78 	unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
79 
80 	if (sbi->used_clusters == EXFAT_CLUSTERS_UNTRACKED) {
81 		mutex_lock(&sbi->s_lock);
82 		if (exfat_count_used_clusters(sb, &sbi->used_clusters)) {
83 			mutex_unlock(&sbi->s_lock);
84 			return -EIO;
85 		}
86 		mutex_unlock(&sbi->s_lock);
87 	}
88 
89 	buf->f_type = sb->s_magic;
90 	buf->f_bsize = sbi->cluster_size;
91 	buf->f_blocks = sbi->num_clusters - 2; /* clu 0 & 1 */
92 	buf->f_bfree = buf->f_blocks - sbi->used_clusters;
93 	buf->f_bavail = buf->f_bfree;
94 	buf->f_fsid.val[0] = (unsigned int)id;
95 	buf->f_fsid.val[1] = (unsigned int)(id >> 32);
96 	/* Unicode utf16 255 characters */
97 	buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE;
98 	return 0;
99 }
100 
101 int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)
102 {
103 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
104 	struct pbr64 *bpb = (struct pbr64 *)sbi->pbr_bh->b_data;
105 	bool sync = 0;
106 
107 	/* flags are not changed */
108 	if (sbi->vol_flag == new_flag)
109 		return 0;
110 
111 	sbi->vol_flag = new_flag;
112 
113 	/* skip updating volume dirty flag,
114 	 * if this volume has been mounted with read-only
115 	 */
116 	if (sb_rdonly(sb))
117 		return 0;
118 
119 	bpb->bsx.vol_flags = cpu_to_le16(new_flag);
120 
121 	if (new_flag == VOL_DIRTY && !buffer_dirty(sbi->pbr_bh))
122 		sync = true;
123 	else
124 		sync = false;
125 
126 	set_buffer_uptodate(sbi->pbr_bh);
127 	mark_buffer_dirty(sbi->pbr_bh);
128 
129 	if (sync)
130 		sync_dirty_buffer(sbi->pbr_bh);
131 	return 0;
132 }
133 
134 static int exfat_show_options(struct seq_file *m, struct dentry *root)
135 {
136 	struct super_block *sb = root->d_sb;
137 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
138 	struct exfat_mount_options *opts = &sbi->options;
139 
140 	/* Show partition info */
141 	if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
142 		seq_printf(m, ",uid=%u",
143 				from_kuid_munged(&init_user_ns, opts->fs_uid));
144 	if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
145 		seq_printf(m, ",gid=%u",
146 				from_kgid_munged(&init_user_ns, opts->fs_gid));
147 	seq_printf(m, ",fmask=%04o,dmask=%04o", opts->fs_fmask, opts->fs_dmask);
148 	if (opts->allow_utime)
149 		seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
150 	if (opts->utf8)
151 		seq_puts(m, ",iocharset=utf8");
152 	else if (sbi->nls_io)
153 		seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
154 	if (opts->errors == EXFAT_ERRORS_CONT)
155 		seq_puts(m, ",errors=continue");
156 	else if (opts->errors == EXFAT_ERRORS_PANIC)
157 		seq_puts(m, ",errors=panic");
158 	else
159 		seq_puts(m, ",errors=remount-ro");
160 	if (opts->discard)
161 		seq_puts(m, ",discard");
162 	if (opts->time_offset)
163 		seq_printf(m, ",time_offset=%d", opts->time_offset);
164 	return 0;
165 }
166 
167 static struct inode *exfat_alloc_inode(struct super_block *sb)
168 {
169 	struct exfat_inode_info *ei;
170 
171 	ei = kmem_cache_alloc(exfat_inode_cachep, GFP_NOFS);
172 	if (!ei)
173 		return NULL;
174 
175 	init_rwsem(&ei->truncate_lock);
176 	return &ei->vfs_inode;
177 }
178 
179 static void exfat_free_inode(struct inode *inode)
180 {
181 	kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
182 }
183 
184 static const struct super_operations exfat_sops = {
185 	.alloc_inode	= exfat_alloc_inode,
186 	.free_inode	= exfat_free_inode,
187 	.write_inode	= exfat_write_inode,
188 	.evict_inode	= exfat_evict_inode,
189 	.put_super	= exfat_put_super,
190 	.sync_fs	= exfat_sync_fs,
191 	.statfs		= exfat_statfs,
192 	.show_options	= exfat_show_options,
193 };
194 
195 enum {
196 	Opt_uid,
197 	Opt_gid,
198 	Opt_umask,
199 	Opt_dmask,
200 	Opt_fmask,
201 	Opt_allow_utime,
202 	Opt_charset,
203 	Opt_errors,
204 	Opt_discard,
205 	Opt_time_offset,
206 
207 	/* Deprecated options */
208 	Opt_utf8,
209 	Opt_debug,
210 	Opt_namecase,
211 	Opt_codepage,
212 };
213 
214 static const struct constant_table exfat_param_enums[] = {
215 	{ "continue",		EXFAT_ERRORS_CONT },
216 	{ "panic",		EXFAT_ERRORS_PANIC },
217 	{ "remount-ro",		EXFAT_ERRORS_RO },
218 	{}
219 };
220 
221 static const struct fs_parameter_spec exfat_parameters[] = {
222 	fsparam_u32("uid",			Opt_uid),
223 	fsparam_u32("gid",			Opt_gid),
224 	fsparam_u32oct("umask",			Opt_umask),
225 	fsparam_u32oct("dmask",			Opt_dmask),
226 	fsparam_u32oct("fmask",			Opt_fmask),
227 	fsparam_u32oct("allow_utime",		Opt_allow_utime),
228 	fsparam_string("iocharset",		Opt_charset),
229 	fsparam_enum("errors",			Opt_errors, exfat_param_enums),
230 	fsparam_flag("discard",			Opt_discard),
231 	fsparam_s32("time_offset",		Opt_time_offset),
232 	__fsparam(NULL, "utf8",			Opt_utf8, fs_param_deprecated,
233 		  NULL),
234 	__fsparam(NULL, "debug",		Opt_debug, fs_param_deprecated,
235 		  NULL),
236 	__fsparam(fs_param_is_u32, "namecase",	Opt_namecase,
237 		  fs_param_deprecated, NULL),
238 	__fsparam(fs_param_is_u32, "codepage",	Opt_codepage,
239 		  fs_param_deprecated, NULL),
240 	{}
241 };
242 
243 static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
244 {
245 	struct exfat_sb_info *sbi = fc->s_fs_info;
246 	struct exfat_mount_options *opts = &sbi->options;
247 	struct fs_parse_result result;
248 	int opt;
249 
250 	opt = fs_parse(fc, exfat_parameters, param, &result);
251 	if (opt < 0)
252 		return opt;
253 
254 	switch (opt) {
255 	case Opt_uid:
256 		opts->fs_uid = make_kuid(current_user_ns(), result.uint_32);
257 		break;
258 	case Opt_gid:
259 		opts->fs_gid = make_kgid(current_user_ns(), result.uint_32);
260 		break;
261 	case Opt_umask:
262 		opts->fs_fmask = result.uint_32;
263 		opts->fs_dmask = result.uint_32;
264 		break;
265 	case Opt_dmask:
266 		opts->fs_dmask = result.uint_32;
267 		break;
268 	case Opt_fmask:
269 		opts->fs_fmask = result.uint_32;
270 		break;
271 	case Opt_allow_utime:
272 		opts->allow_utime = result.uint_32 & 0022;
273 		break;
274 	case Opt_charset:
275 		exfat_free_iocharset(sbi);
276 		opts->iocharset = kstrdup(param->string, GFP_KERNEL);
277 		if (!opts->iocharset)
278 			return -ENOMEM;
279 		break;
280 	case Opt_errors:
281 		opts->errors = result.uint_32;
282 		break;
283 	case Opt_discard:
284 		opts->discard = 1;
285 		break;
286 	case Opt_time_offset:
287 		/*
288 		 * Make the limit 24 just in case someone invents something
289 		 * unusual.
290 		 */
291 		if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
292 			return -EINVAL;
293 		opts->time_offset = result.int_32;
294 		break;
295 	case Opt_utf8:
296 	case Opt_debug:
297 	case Opt_namecase:
298 	case Opt_codepage:
299 		break;
300 	default:
301 		return -EINVAL;
302 	}
303 
304 	return 0;
305 }
306 
307 static void exfat_hash_init(struct super_block *sb)
308 {
309 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
310 	int i;
311 
312 	spin_lock_init(&sbi->inode_hash_lock);
313 	for (i = 0; i < EXFAT_HASH_SIZE; i++)
314 		INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
315 }
316 
317 static int exfat_read_root(struct inode *inode)
318 {
319 	struct super_block *sb = inode->i_sb;
320 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
321 	struct exfat_inode_info *ei = EXFAT_I(inode);
322 	struct exfat_chain cdir;
323 	int num_subdirs, num_clu = 0;
324 
325 	exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
326 	ei->entry = -1;
327 	ei->start_clu = sbi->root_dir;
328 	ei->flags = ALLOC_FAT_CHAIN;
329 	ei->type = TYPE_DIR;
330 	ei->version = 0;
331 	ei->rwoffset = 0;
332 	ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
333 	ei->hint_stat.eidx = 0;
334 	ei->hint_stat.clu = sbi->root_dir;
335 	ei->hint_femp.eidx = EXFAT_HINT_NONE;
336 
337 	exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
338 	if (exfat_count_num_clusters(sb, &cdir, &num_clu))
339 		return -EIO;
340 	i_size_write(inode, num_clu << sbi->cluster_size_bits);
341 
342 	num_subdirs = exfat_count_dir_entries(sb, &cdir);
343 	if (num_subdirs < 0)
344 		return -EIO;
345 	set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
346 
347 	inode->i_uid = sbi->options.fs_uid;
348 	inode->i_gid = sbi->options.fs_gid;
349 	inode_inc_iversion(inode);
350 	inode->i_generation = 0;
351 	inode->i_mode = exfat_make_mode(sbi, ATTR_SUBDIR, 0777);
352 	inode->i_op = &exfat_dir_inode_operations;
353 	inode->i_fop = &exfat_dir_operations;
354 
355 	inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1))
356 			& ~(sbi->cluster_size - 1)) >> inode->i_blkbits;
357 	EXFAT_I(inode)->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
358 	EXFAT_I(inode)->i_size_aligned = i_size_read(inode);
359 	EXFAT_I(inode)->i_size_ondisk = i_size_read(inode);
360 
361 	exfat_save_attr(inode, ATTR_SUBDIR);
362 	inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
363 		current_time(inode);
364 	exfat_truncate_atime(&inode->i_atime);
365 	exfat_cache_init_inode(inode);
366 	return 0;
367 }
368 
369 static struct pbr *exfat_read_pbr_with_logical_sector(struct super_block *sb)
370 {
371 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
372 	struct pbr *p_pbr = (struct pbr *) (sbi->pbr_bh)->b_data;
373 	unsigned short logical_sect = 0;
374 
375 	logical_sect = 1 << p_pbr->bsx.f64.sect_size_bits;
376 
377 	if (!is_power_of_2(logical_sect) ||
378 	    logical_sect < 512 || logical_sect > 4096) {
379 		exfat_msg(sb, KERN_ERR, "bogus logical sector size %u",
380 				logical_sect);
381 		return NULL;
382 	}
383 
384 	if (logical_sect < sb->s_blocksize) {
385 		exfat_msg(sb, KERN_ERR,
386 			"logical sector size too small for device (logical sector size = %u)",
387 			logical_sect);
388 		return NULL;
389 	}
390 
391 	if (logical_sect > sb->s_blocksize) {
392 		brelse(sbi->pbr_bh);
393 		sbi->pbr_bh = NULL;
394 
395 		if (!sb_set_blocksize(sb, logical_sect)) {
396 			exfat_msg(sb, KERN_ERR,
397 				"unable to set blocksize %u", logical_sect);
398 			return NULL;
399 		}
400 		sbi->pbr_bh = sb_bread(sb, 0);
401 		if (!sbi->pbr_bh) {
402 			exfat_msg(sb, KERN_ERR,
403 				"unable to read boot sector (logical sector size = %lu)",
404 				sb->s_blocksize);
405 			return NULL;
406 		}
407 
408 		p_pbr = (struct pbr *)sbi->pbr_bh->b_data;
409 	}
410 	return p_pbr;
411 }
412 
413 /* mount the file system volume */
414 static int __exfat_fill_super(struct super_block *sb)
415 {
416 	int ret;
417 	struct pbr *p_pbr;
418 	struct pbr64 *p_bpb;
419 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
420 
421 	/* set block size to read super block */
422 	sb_min_blocksize(sb, 512);
423 
424 	/* read boot sector */
425 	sbi->pbr_bh = sb_bread(sb, 0);
426 	if (!sbi->pbr_bh) {
427 		exfat_msg(sb, KERN_ERR, "unable to read boot sector");
428 		return -EIO;
429 	}
430 
431 	/* PRB is read */
432 	p_pbr = (struct pbr *)sbi->pbr_bh->b_data;
433 
434 	/* check the validity of PBR */
435 	if (le16_to_cpu((p_pbr->signature)) != PBR_SIGNATURE) {
436 		exfat_msg(sb, KERN_ERR, "invalid boot record signature");
437 		ret = -EINVAL;
438 		goto free_bh;
439 	}
440 
441 
442 	/* check logical sector size */
443 	p_pbr = exfat_read_pbr_with_logical_sector(sb);
444 	if (!p_pbr) {
445 		ret = -EIO;
446 		goto free_bh;
447 	}
448 
449 	/*
450 	 * res_zero field must be filled with zero to prevent mounting
451 	 * from FAT volume.
452 	 */
453 	if (memchr_inv(p_pbr->bpb.f64.res_zero, 0,
454 			sizeof(p_pbr->bpb.f64.res_zero))) {
455 		ret = -EINVAL;
456 		goto free_bh;
457 	}
458 
459 	p_bpb = (struct pbr64 *)p_pbr;
460 	if (!p_bpb->bsx.num_fats) {
461 		exfat_msg(sb, KERN_ERR, "bogus number of FAT structure");
462 		ret = -EINVAL;
463 		goto free_bh;
464 	}
465 
466 	sbi->sect_per_clus = 1 << p_bpb->bsx.sect_per_clus_bits;
467 	sbi->sect_per_clus_bits = p_bpb->bsx.sect_per_clus_bits;
468 	sbi->cluster_size_bits = sbi->sect_per_clus_bits + sb->s_blocksize_bits;
469 	sbi->cluster_size = 1 << sbi->cluster_size_bits;
470 	sbi->num_FAT_sectors = le32_to_cpu(p_bpb->bsx.fat_length);
471 	sbi->FAT1_start_sector = le32_to_cpu(p_bpb->bsx.fat_offset);
472 	sbi->FAT2_start_sector = p_bpb->bsx.num_fats == 1 ?
473 		sbi->FAT1_start_sector :
474 			sbi->FAT1_start_sector + sbi->num_FAT_sectors;
475 	sbi->data_start_sector = le32_to_cpu(p_bpb->bsx.clu_offset);
476 	sbi->num_sectors = le64_to_cpu(p_bpb->bsx.vol_length);
477 	/* because the cluster index starts with 2 */
478 	sbi->num_clusters = le32_to_cpu(p_bpb->bsx.clu_count) +
479 		EXFAT_RESERVED_CLUSTERS;
480 
481 	sbi->root_dir = le32_to_cpu(p_bpb->bsx.root_cluster);
482 	sbi->dentries_per_clu = 1 <<
483 		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
484 
485 	sbi->vol_flag = le16_to_cpu(p_bpb->bsx.vol_flags);
486 	sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
487 	sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED;
488 
489 	if (le16_to_cpu(p_bpb->bsx.vol_flags) & VOL_DIRTY) {
490 		sbi->vol_flag |= VOL_DIRTY;
491 		exfat_msg(sb, KERN_WARNING,
492 			"Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
493 	}
494 
495 	/* exFAT file size is limited by a disk volume size */
496 	sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) <<
497 		sbi->cluster_size_bits;
498 
499 	ret = exfat_create_upcase_table(sb);
500 	if (ret) {
501 		exfat_msg(sb, KERN_ERR, "failed to load upcase table");
502 		goto free_bh;
503 	}
504 
505 	ret = exfat_load_bitmap(sb);
506 	if (ret) {
507 		exfat_msg(sb, KERN_ERR, "failed to load alloc-bitmap");
508 		goto free_upcase_table;
509 	}
510 
511 	ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
512 	if (ret) {
513 		exfat_msg(sb, KERN_ERR, "failed to scan clusters");
514 		goto free_alloc_bitmap;
515 	}
516 
517 	return 0;
518 
519 free_alloc_bitmap:
520 	exfat_free_bitmap(sbi);
521 free_upcase_table:
522 	exfat_free_upcase_table(sbi);
523 free_bh:
524 	brelse(sbi->pbr_bh);
525 	return ret;
526 }
527 
528 static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
529 {
530 	struct exfat_sb_info *sbi = sb->s_fs_info;
531 	struct exfat_mount_options *opts = &sbi->options;
532 	struct inode *root_inode;
533 	int err;
534 
535 	if (opts->allow_utime == (unsigned short)-1)
536 		opts->allow_utime = ~opts->fs_dmask & 0022;
537 
538 	if (opts->discard) {
539 		struct request_queue *q = bdev_get_queue(sb->s_bdev);
540 
541 		if (!blk_queue_discard(q)) {
542 			exfat_msg(sb, KERN_WARNING,
543 				"mounting with \"discard\" option, but the device does not support discard");
544 			opts->discard = 0;
545 		}
546 	}
547 
548 	sb->s_flags |= SB_NODIRATIME;
549 	sb->s_magic = EXFAT_SUPER_MAGIC;
550 	sb->s_op = &exfat_sops;
551 
552 	sb->s_time_gran = 10 * NSEC_PER_MSEC;
553 	sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
554 	sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
555 
556 	err = __exfat_fill_super(sb);
557 	if (err) {
558 		exfat_msg(sb, KERN_ERR, "failed to recognize exfat type");
559 		goto check_nls_io;
560 	}
561 
562 	/* set up enough so that it can read an inode */
563 	exfat_hash_init(sb);
564 
565 	if (!strcmp(sbi->options.iocharset, "utf8"))
566 		opts->utf8 = 1;
567 	else {
568 		sbi->nls_io = load_nls(sbi->options.iocharset);
569 		if (!sbi->nls_io) {
570 			exfat_msg(sb, KERN_ERR, "IO charset %s not found",
571 					sbi->options.iocharset);
572 			err = -EINVAL;
573 			goto free_table;
574 		}
575 	}
576 
577 	if (sbi->options.utf8)
578 		sb->s_d_op = &exfat_utf8_dentry_ops;
579 	else
580 		sb->s_d_op = &exfat_dentry_ops;
581 
582 	root_inode = new_inode(sb);
583 	if (!root_inode) {
584 		exfat_msg(sb, KERN_ERR, "failed to allocate root inode.");
585 		err = -ENOMEM;
586 		goto free_table;
587 	}
588 
589 	root_inode->i_ino = EXFAT_ROOT_INO;
590 	inode_set_iversion(root_inode, 1);
591 	err = exfat_read_root(root_inode);
592 	if (err) {
593 		exfat_msg(sb, KERN_ERR, "failed to initialize root inode.");
594 		goto put_inode;
595 	}
596 
597 	exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
598 	insert_inode_hash(root_inode);
599 
600 	sb->s_root = d_make_root(root_inode);
601 	if (!sb->s_root) {
602 		exfat_msg(sb, KERN_ERR, "failed to get the root dentry");
603 		err = -ENOMEM;
604 		goto put_inode;
605 	}
606 
607 	return 0;
608 
609 put_inode:
610 	iput(root_inode);
611 	sb->s_root = NULL;
612 
613 free_table:
614 	exfat_free_upcase_table(sbi);
615 	exfat_free_bitmap(sbi);
616 	brelse(sbi->pbr_bh);
617 
618 check_nls_io:
619 	unload_nls(sbi->nls_io);
620 	exfat_free_iocharset(sbi);
621 	sb->s_fs_info = NULL;
622 	kfree(sbi);
623 	return err;
624 }
625 
626 static int exfat_get_tree(struct fs_context *fc)
627 {
628 	return get_tree_bdev(fc, exfat_fill_super);
629 }
630 
631 static void exfat_free(struct fs_context *fc)
632 {
633 	kfree(fc->s_fs_info);
634 }
635 
636 static const struct fs_context_operations exfat_context_ops = {
637 	.parse_param	= exfat_parse_param,
638 	.get_tree	= exfat_get_tree,
639 	.free		= exfat_free,
640 };
641 
642 static int exfat_init_fs_context(struct fs_context *fc)
643 {
644 	struct exfat_sb_info *sbi;
645 
646 	sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
647 	if (!sbi)
648 		return -ENOMEM;
649 
650 	mutex_init(&sbi->s_lock);
651 	ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
652 			DEFAULT_RATELIMIT_BURST);
653 
654 	sbi->options.fs_uid = current_uid();
655 	sbi->options.fs_gid = current_gid();
656 	sbi->options.fs_fmask = current->fs->umask;
657 	sbi->options.fs_dmask = current->fs->umask;
658 	sbi->options.allow_utime = -1;
659 	sbi->options.iocharset = exfat_default_iocharset;
660 	sbi->options.errors = EXFAT_ERRORS_RO;
661 
662 	fc->s_fs_info = sbi;
663 	fc->ops = &exfat_context_ops;
664 	return 0;
665 }
666 
667 static struct file_system_type exfat_fs_type = {
668 	.owner			= THIS_MODULE,
669 	.name			= "exfat",
670 	.init_fs_context	= exfat_init_fs_context,
671 	.parameters		= exfat_parameters,
672 	.kill_sb		= kill_block_super,
673 	.fs_flags		= FS_REQUIRES_DEV,
674 };
675 
676 static void exfat_inode_init_once(void *foo)
677 {
678 	struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
679 
680 	INIT_HLIST_NODE(&ei->i_hash_fat);
681 	inode_init_once(&ei->vfs_inode);
682 }
683 
684 static int __init init_exfat_fs(void)
685 {
686 	int err;
687 
688 	err = exfat_cache_init();
689 	if (err)
690 		return err;
691 
692 	exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
693 			sizeof(struct exfat_inode_info),
694 			0, SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
695 			exfat_inode_init_once);
696 	if (!exfat_inode_cachep) {
697 		err = -ENOMEM;
698 		goto shutdown_cache;
699 	}
700 
701 	err = register_filesystem(&exfat_fs_type);
702 	if (err)
703 		goto destroy_cache;
704 
705 	return 0;
706 
707 destroy_cache:
708 	kmem_cache_destroy(exfat_inode_cachep);
709 shutdown_cache:
710 	exfat_cache_shutdown();
711 	return err;
712 }
713 
714 static void __exit exit_exfat_fs(void)
715 {
716 	/*
717 	 * Make sure all delayed rcu free inodes are flushed before we
718 	 * destroy cache.
719 	 */
720 	rcu_barrier();
721 	kmem_cache_destroy(exfat_inode_cachep);
722 	unregister_filesystem(&exfat_fs_type);
723 	exfat_cache_shutdown();
724 }
725 
726 module_init(init_exfat_fs);
727 module_exit(exit_exfat_fs);
728 
729 MODULE_ALIAS_FS("exfat");
730 MODULE_LICENSE("GPL");
731 MODULE_DESCRIPTION("exFAT filesystem support");
732 MODULE_AUTHOR("Samsung Electronics Co., Ltd.");
733