xref: /openbmc/linux/fs/exfat/super.c (revision adb57164)
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 
208 static const struct constant_table exfat_param_enums[] = {
209 	{ "continue",		EXFAT_ERRORS_CONT },
210 	{ "panic",		EXFAT_ERRORS_PANIC },
211 	{ "remount-ro",		EXFAT_ERRORS_RO },
212 	{}
213 };
214 
215 static const struct fs_parameter_spec exfat_parameters[] = {
216 	fsparam_u32("uid",			Opt_uid),
217 	fsparam_u32("gid",			Opt_gid),
218 	fsparam_u32oct("umask",			Opt_umask),
219 	fsparam_u32oct("dmask",			Opt_dmask),
220 	fsparam_u32oct("fmask",			Opt_fmask),
221 	fsparam_u32oct("allow_utime",		Opt_allow_utime),
222 	fsparam_string("iocharset",		Opt_charset),
223 	fsparam_enum("errors",			Opt_errors, exfat_param_enums),
224 	fsparam_flag("discard",			Opt_discard),
225 	fsparam_s32("time_offset",		Opt_time_offset),
226 	{}
227 };
228 
229 static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
230 {
231 	struct exfat_sb_info *sbi = fc->s_fs_info;
232 	struct exfat_mount_options *opts = &sbi->options;
233 	struct fs_parse_result result;
234 	int opt;
235 
236 	opt = fs_parse(fc, exfat_parameters, param, &result);
237 	if (opt < 0)
238 		return opt;
239 
240 	switch (opt) {
241 	case Opt_uid:
242 		opts->fs_uid = make_kuid(current_user_ns(), result.uint_32);
243 		break;
244 	case Opt_gid:
245 		opts->fs_gid = make_kgid(current_user_ns(), result.uint_32);
246 		break;
247 	case Opt_umask:
248 		opts->fs_fmask = result.uint_32;
249 		opts->fs_dmask = result.uint_32;
250 		break;
251 	case Opt_dmask:
252 		opts->fs_dmask = result.uint_32;
253 		break;
254 	case Opt_fmask:
255 		opts->fs_fmask = result.uint_32;
256 		break;
257 	case Opt_allow_utime:
258 		opts->allow_utime = result.uint_32 & 0022;
259 		break;
260 	case Opt_charset:
261 		exfat_free_iocharset(sbi);
262 		opts->iocharset = kstrdup(param->string, GFP_KERNEL);
263 		if (!opts->iocharset)
264 			return -ENOMEM;
265 		break;
266 	case Opt_errors:
267 		opts->errors = result.uint_32;
268 		break;
269 	case Opt_discard:
270 		opts->discard = 1;
271 		break;
272 	case Opt_time_offset:
273 		/*
274 		 * Make the limit 24 just in case someone invents something
275 		 * unusual.
276 		 */
277 		if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
278 			return -EINVAL;
279 		opts->time_offset = result.int_32;
280 		break;
281 	default:
282 		return -EINVAL;
283 	}
284 
285 	return 0;
286 }
287 
288 static void exfat_hash_init(struct super_block *sb)
289 {
290 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
291 	int i;
292 
293 	spin_lock_init(&sbi->inode_hash_lock);
294 	for (i = 0; i < EXFAT_HASH_SIZE; i++)
295 		INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
296 }
297 
298 static int exfat_read_root(struct inode *inode)
299 {
300 	struct super_block *sb = inode->i_sb;
301 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
302 	struct exfat_inode_info *ei = EXFAT_I(inode);
303 	struct exfat_chain cdir;
304 	int num_subdirs, num_clu = 0;
305 
306 	exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
307 	ei->entry = -1;
308 	ei->start_clu = sbi->root_dir;
309 	ei->flags = ALLOC_FAT_CHAIN;
310 	ei->type = TYPE_DIR;
311 	ei->version = 0;
312 	ei->rwoffset = 0;
313 	ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
314 	ei->hint_stat.eidx = 0;
315 	ei->hint_stat.clu = sbi->root_dir;
316 	ei->hint_femp.eidx = EXFAT_HINT_NONE;
317 
318 	exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
319 	if (exfat_count_num_clusters(sb, &cdir, &num_clu))
320 		return -EIO;
321 	i_size_write(inode, num_clu << sbi->cluster_size_bits);
322 
323 	num_subdirs = exfat_count_dir_entries(sb, &cdir);
324 	if (num_subdirs < 0)
325 		return -EIO;
326 	set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
327 
328 	inode->i_uid = sbi->options.fs_uid;
329 	inode->i_gid = sbi->options.fs_gid;
330 	inode_inc_iversion(inode);
331 	inode->i_generation = 0;
332 	inode->i_mode = exfat_make_mode(sbi, ATTR_SUBDIR, 0777);
333 	inode->i_op = &exfat_dir_inode_operations;
334 	inode->i_fop = &exfat_dir_operations;
335 
336 	inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1))
337 			& ~(sbi->cluster_size - 1)) >> inode->i_blkbits;
338 	EXFAT_I(inode)->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
339 	EXFAT_I(inode)->i_size_aligned = i_size_read(inode);
340 	EXFAT_I(inode)->i_size_ondisk = i_size_read(inode);
341 
342 	exfat_save_attr(inode, ATTR_SUBDIR);
343 	inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
344 		current_time(inode);
345 	exfat_truncate_atime(&inode->i_atime);
346 	exfat_cache_init_inode(inode);
347 	return 0;
348 }
349 
350 static struct pbr *exfat_read_pbr_with_logical_sector(struct super_block *sb)
351 {
352 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
353 	struct pbr *p_pbr = (struct pbr *) (sbi->pbr_bh)->b_data;
354 	unsigned short logical_sect = 0;
355 
356 	logical_sect = 1 << p_pbr->bsx.f64.sect_size_bits;
357 
358 	if (!is_power_of_2(logical_sect) ||
359 	    logical_sect < 512 || logical_sect > 4096) {
360 		exfat_msg(sb, KERN_ERR, "bogus logical sector size %u",
361 				logical_sect);
362 		return NULL;
363 	}
364 
365 	if (logical_sect < sb->s_blocksize) {
366 		exfat_msg(sb, KERN_ERR,
367 			"logical sector size too small for device (logical sector size = %u)",
368 			logical_sect);
369 		return NULL;
370 	}
371 
372 	if (logical_sect > sb->s_blocksize) {
373 		brelse(sbi->pbr_bh);
374 		sbi->pbr_bh = NULL;
375 
376 		if (!sb_set_blocksize(sb, logical_sect)) {
377 			exfat_msg(sb, KERN_ERR,
378 				"unable to set blocksize %u", logical_sect);
379 			return NULL;
380 		}
381 		sbi->pbr_bh = sb_bread(sb, 0);
382 		if (!sbi->pbr_bh) {
383 			exfat_msg(sb, KERN_ERR,
384 				"unable to read boot sector (logical sector size = %lu)",
385 				sb->s_blocksize);
386 			return NULL;
387 		}
388 
389 		p_pbr = (struct pbr *)sbi->pbr_bh->b_data;
390 	}
391 	return p_pbr;
392 }
393 
394 /* mount the file system volume */
395 static int __exfat_fill_super(struct super_block *sb)
396 {
397 	int ret;
398 	struct pbr *p_pbr;
399 	struct pbr64 *p_bpb;
400 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
401 
402 	/* set block size to read super block */
403 	sb_min_blocksize(sb, 512);
404 
405 	/* read boot sector */
406 	sbi->pbr_bh = sb_bread(sb, 0);
407 	if (!sbi->pbr_bh) {
408 		exfat_msg(sb, KERN_ERR, "unable to read boot sector");
409 		return -EIO;
410 	}
411 
412 	/* PRB is read */
413 	p_pbr = (struct pbr *)sbi->pbr_bh->b_data;
414 
415 	/* check the validity of PBR */
416 	if (le16_to_cpu((p_pbr->signature)) != PBR_SIGNATURE) {
417 		exfat_msg(sb, KERN_ERR, "invalid boot record signature");
418 		ret = -EINVAL;
419 		goto free_bh;
420 	}
421 
422 
423 	/* check logical sector size */
424 	p_pbr = exfat_read_pbr_with_logical_sector(sb);
425 	if (!p_pbr) {
426 		ret = -EIO;
427 		goto free_bh;
428 	}
429 
430 	/*
431 	 * res_zero field must be filled with zero to prevent mounting
432 	 * from FAT volume.
433 	 */
434 	if (memchr_inv(p_pbr->bpb.f64.res_zero, 0,
435 			sizeof(p_pbr->bpb.f64.res_zero))) {
436 		ret = -EINVAL;
437 		goto free_bh;
438 	}
439 
440 	p_bpb = (struct pbr64 *)p_pbr;
441 	if (!p_bpb->bsx.num_fats) {
442 		exfat_msg(sb, KERN_ERR, "bogus number of FAT structure");
443 		ret = -EINVAL;
444 		goto free_bh;
445 	}
446 
447 	sbi->sect_per_clus = 1 << p_bpb->bsx.sect_per_clus_bits;
448 	sbi->sect_per_clus_bits = p_bpb->bsx.sect_per_clus_bits;
449 	sbi->cluster_size_bits = sbi->sect_per_clus_bits + sb->s_blocksize_bits;
450 	sbi->cluster_size = 1 << sbi->cluster_size_bits;
451 	sbi->num_FAT_sectors = le32_to_cpu(p_bpb->bsx.fat_length);
452 	sbi->FAT1_start_sector = le32_to_cpu(p_bpb->bsx.fat_offset);
453 	sbi->FAT2_start_sector = p_bpb->bsx.num_fats == 1 ?
454 		sbi->FAT1_start_sector :
455 			sbi->FAT1_start_sector + sbi->num_FAT_sectors;
456 	sbi->data_start_sector = le32_to_cpu(p_bpb->bsx.clu_offset);
457 	sbi->num_sectors = le64_to_cpu(p_bpb->bsx.vol_length);
458 	/* because the cluster index starts with 2 */
459 	sbi->num_clusters = le32_to_cpu(p_bpb->bsx.clu_count) +
460 		EXFAT_RESERVED_CLUSTERS;
461 
462 	sbi->root_dir = le32_to_cpu(p_bpb->bsx.root_cluster);
463 	sbi->dentries_per_clu = 1 <<
464 		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
465 
466 	sbi->vol_flag = le16_to_cpu(p_bpb->bsx.vol_flags);
467 	sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
468 	sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED;
469 
470 	if (le16_to_cpu(p_bpb->bsx.vol_flags) & VOL_DIRTY) {
471 		sbi->vol_flag |= VOL_DIRTY;
472 		exfat_msg(sb, KERN_WARNING,
473 			"Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
474 	}
475 
476 	/* exFAT file size is limited by a disk volume size */
477 	sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) <<
478 		sbi->cluster_size_bits;
479 
480 	ret = exfat_create_upcase_table(sb);
481 	if (ret) {
482 		exfat_msg(sb, KERN_ERR, "failed to load upcase table");
483 		goto free_bh;
484 	}
485 
486 	ret = exfat_load_bitmap(sb);
487 	if (ret) {
488 		exfat_msg(sb, KERN_ERR, "failed to load alloc-bitmap");
489 		goto free_upcase_table;
490 	}
491 
492 	ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
493 	if (ret) {
494 		exfat_msg(sb, KERN_ERR, "failed to scan clusters");
495 		goto free_alloc_bitmap;
496 	}
497 
498 	return 0;
499 
500 free_alloc_bitmap:
501 	exfat_free_bitmap(sbi);
502 free_upcase_table:
503 	exfat_free_upcase_table(sbi);
504 free_bh:
505 	brelse(sbi->pbr_bh);
506 	return ret;
507 }
508 
509 static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
510 {
511 	struct exfat_sb_info *sbi = sb->s_fs_info;
512 	struct exfat_mount_options *opts = &sbi->options;
513 	struct inode *root_inode;
514 	int err;
515 
516 	if (opts->allow_utime == (unsigned short)-1)
517 		opts->allow_utime = ~opts->fs_dmask & 0022;
518 
519 	if (opts->discard) {
520 		struct request_queue *q = bdev_get_queue(sb->s_bdev);
521 
522 		if (!blk_queue_discard(q)) {
523 			exfat_msg(sb, KERN_WARNING,
524 				"mounting with \"discard\" option, but the device does not support discard");
525 			opts->discard = 0;
526 		}
527 	}
528 
529 	sb->s_flags |= SB_NODIRATIME;
530 	sb->s_magic = EXFAT_SUPER_MAGIC;
531 	sb->s_op = &exfat_sops;
532 
533 	sb->s_time_gran = 10 * NSEC_PER_MSEC;
534 	sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
535 	sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
536 
537 	err = __exfat_fill_super(sb);
538 	if (err) {
539 		exfat_msg(sb, KERN_ERR, "failed to recognize exfat type");
540 		goto check_nls_io;
541 	}
542 
543 	/* set up enough so that it can read an inode */
544 	exfat_hash_init(sb);
545 
546 	if (!strcmp(sbi->options.iocharset, "utf8"))
547 		opts->utf8 = 1;
548 	else {
549 		sbi->nls_io = load_nls(sbi->options.iocharset);
550 		if (!sbi->nls_io) {
551 			exfat_msg(sb, KERN_ERR, "IO charset %s not found",
552 					sbi->options.iocharset);
553 			err = -EINVAL;
554 			goto free_table;
555 		}
556 	}
557 
558 	if (sbi->options.utf8)
559 		sb->s_d_op = &exfat_utf8_dentry_ops;
560 	else
561 		sb->s_d_op = &exfat_dentry_ops;
562 
563 	root_inode = new_inode(sb);
564 	if (!root_inode) {
565 		exfat_msg(sb, KERN_ERR, "failed to allocate root inode.");
566 		err = -ENOMEM;
567 		goto free_table;
568 	}
569 
570 	root_inode->i_ino = EXFAT_ROOT_INO;
571 	inode_set_iversion(root_inode, 1);
572 	err = exfat_read_root(root_inode);
573 	if (err) {
574 		exfat_msg(sb, KERN_ERR, "failed to initialize root inode.");
575 		goto put_inode;
576 	}
577 
578 	exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
579 	insert_inode_hash(root_inode);
580 
581 	sb->s_root = d_make_root(root_inode);
582 	if (!sb->s_root) {
583 		exfat_msg(sb, KERN_ERR, "failed to get the root dentry");
584 		err = -ENOMEM;
585 		goto put_inode;
586 	}
587 
588 	return 0;
589 
590 put_inode:
591 	iput(root_inode);
592 	sb->s_root = NULL;
593 
594 free_table:
595 	exfat_free_upcase_table(sbi);
596 	exfat_free_bitmap(sbi);
597 	brelse(sbi->pbr_bh);
598 
599 check_nls_io:
600 	unload_nls(sbi->nls_io);
601 	exfat_free_iocharset(sbi);
602 	sb->s_fs_info = NULL;
603 	kfree(sbi);
604 	return err;
605 }
606 
607 static int exfat_get_tree(struct fs_context *fc)
608 {
609 	return get_tree_bdev(fc, exfat_fill_super);
610 }
611 
612 static void exfat_free(struct fs_context *fc)
613 {
614 	kfree(fc->s_fs_info);
615 }
616 
617 static const struct fs_context_operations exfat_context_ops = {
618 	.parse_param	= exfat_parse_param,
619 	.get_tree	= exfat_get_tree,
620 	.free		= exfat_free,
621 };
622 
623 static int exfat_init_fs_context(struct fs_context *fc)
624 {
625 	struct exfat_sb_info *sbi;
626 
627 	sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
628 	if (!sbi)
629 		return -ENOMEM;
630 
631 	mutex_init(&sbi->s_lock);
632 	ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
633 			DEFAULT_RATELIMIT_BURST);
634 
635 	sbi->options.fs_uid = current_uid();
636 	sbi->options.fs_gid = current_gid();
637 	sbi->options.fs_fmask = current->fs->umask;
638 	sbi->options.fs_dmask = current->fs->umask;
639 	sbi->options.allow_utime = -1;
640 	sbi->options.iocharset = exfat_default_iocharset;
641 	sbi->options.errors = EXFAT_ERRORS_RO;
642 
643 	fc->s_fs_info = sbi;
644 	fc->ops = &exfat_context_ops;
645 	return 0;
646 }
647 
648 static struct file_system_type exfat_fs_type = {
649 	.owner			= THIS_MODULE,
650 	.name			= "exfat",
651 	.init_fs_context	= exfat_init_fs_context,
652 	.parameters		= exfat_parameters,
653 	.kill_sb		= kill_block_super,
654 	.fs_flags		= FS_REQUIRES_DEV,
655 };
656 
657 static void exfat_inode_init_once(void *foo)
658 {
659 	struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
660 
661 	INIT_HLIST_NODE(&ei->i_hash_fat);
662 	inode_init_once(&ei->vfs_inode);
663 }
664 
665 static int __init init_exfat_fs(void)
666 {
667 	int err;
668 
669 	err = exfat_cache_init();
670 	if (err)
671 		return err;
672 
673 	exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
674 			sizeof(struct exfat_inode_info),
675 			0, SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
676 			exfat_inode_init_once);
677 	if (!exfat_inode_cachep) {
678 		err = -ENOMEM;
679 		goto shutdown_cache;
680 	}
681 
682 	err = register_filesystem(&exfat_fs_type);
683 	if (err)
684 		goto destroy_cache;
685 
686 	return 0;
687 
688 destroy_cache:
689 	kmem_cache_destroy(exfat_inode_cachep);
690 shutdown_cache:
691 	exfat_cache_shutdown();
692 	return err;
693 }
694 
695 static void __exit exit_exfat_fs(void)
696 {
697 	/*
698 	 * Make sure all delayed rcu free inodes are flushed before we
699 	 * destroy cache.
700 	 */
701 	rcu_barrier();
702 	kmem_cache_destroy(exfat_inode_cachep);
703 	unregister_filesystem(&exfat_fs_type);
704 	exfat_cache_shutdown();
705 }
706 
707 module_init(init_exfat_fs);
708 module_exit(exit_exfat_fs);
709 
710 MODULE_ALIAS_FS("exfat");
711 MODULE_LICENSE("GPL");
712 MODULE_DESCRIPTION("exFAT filesystem support");
713 MODULE_AUTHOR("Samsung Electronics Co., Ltd.");
714