super.c

  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
 25static char exfat_default_iocharset[] = CONFIG_EXFAT_DEFAULT_IOCHARSET;
 26static struct kmem_cache *exfat_inode_cachep;
 27
 28static 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
 34static 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
 44static 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
 55static 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
 72static 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
102int 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
109int 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
116static 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
155int 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
185static void exfat_shutdown(struct super_block *sb)
186{
187	exfat_force_shutdown(sb, EXFAT_GOING_DOWN_NOSYNC);
188}
189
190static 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
202static void exfat_free_inode(struct inode *inode)
203{
204	kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
205}
206
207static 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
218enum {
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
240static 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
247static 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
272static 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
344static 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
354static 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
396static 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
430static 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	if (!sb_min_blocksize(sb, 512)) {
437		exfat_err(sb, "unable to set blocksize");
438		return -EINVAL;
439	}
440
441	/* read boot sector */
442	sbi->boot_bh = sb_bread(sb, 0);
443	if (!sbi->boot_bh) {
444		exfat_err(sb, "unable to read boot sector");
445		return -EIO;
446	}
447	p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
448
449	/* check the validity of BOOT */
450	if (le16_to_cpu((p_boot->signature)) != BOOT_SIGNATURE) {
451		exfat_err(sb, "invalid boot record signature");
452		return -EINVAL;
453	}
454
455	if (memcmp(p_boot->fs_name, STR_EXFAT, BOOTSEC_FS_NAME_LEN)) {
456		exfat_err(sb, "invalid fs_name"); /* fs_name may unprintable */
457		return -EINVAL;
458	}
459
460	/*
461	 * must_be_zero field must be filled with zero to prevent mounting
462	 * from FAT volume.
463	 */
464	if (memchr_inv(p_boot->must_be_zero, 0, sizeof(p_boot->must_be_zero)))
465		return -EINVAL;
466
467	if (p_boot->num_fats != 1 && p_boot->num_fats != 2) {
468		exfat_err(sb, "bogus number of FAT structure");
469		return -EINVAL;
470	}
471
472	/*
473	 * sect_size_bits could be at least 9 and at most 12.
474	 */
475	if (p_boot->sect_size_bits < EXFAT_MIN_SECT_SIZE_BITS ||
476	    p_boot->sect_size_bits > EXFAT_MAX_SECT_SIZE_BITS) {
477		exfat_err(sb, "bogus sector size bits : %u",
478				p_boot->sect_size_bits);
479		return -EINVAL;
480	}
481
482	/*
483	 * sect_per_clus_bits could be at least 0 and at most 25 - sect_size_bits.
484	 */
485	if (p_boot->sect_per_clus_bits > EXFAT_MAX_SECT_PER_CLUS_BITS(p_boot)) {
486		exfat_err(sb, "bogus sectors bits per cluster : %u",
487				p_boot->sect_per_clus_bits);
488		return -EINVAL;
489	}
490
491	sbi->sect_per_clus = 1 << p_boot->sect_per_clus_bits;
492	sbi->sect_per_clus_bits = p_boot->sect_per_clus_bits;
493	sbi->cluster_size_bits = p_boot->sect_per_clus_bits +
494		p_boot->sect_size_bits;
495	sbi->cluster_size = 1 << sbi->cluster_size_bits;
496	sbi->num_FAT_sectors = le32_to_cpu(p_boot->fat_length);
497	sbi->FAT1_start_sector = le32_to_cpu(p_boot->fat_offset);
498	sbi->FAT2_start_sector = le32_to_cpu(p_boot->fat_offset);
499	if (p_boot->num_fats == 2)
500		sbi->FAT2_start_sector += sbi->num_FAT_sectors;
501	sbi->data_start_sector = le32_to_cpu(p_boot->clu_offset);
502	sbi->num_sectors = le64_to_cpu(p_boot->vol_length);
503	/* because the cluster index starts with 2 */
504	sbi->num_clusters = le32_to_cpu(p_boot->clu_count) +
505		EXFAT_RESERVED_CLUSTERS;
506
507	sbi->root_dir = le32_to_cpu(p_boot->root_cluster);
508	sbi->dentries_per_clu = 1 <<
509		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
510
511	sbi->vol_flags = le16_to_cpu(p_boot->vol_flags);
512	sbi->vol_flags_persistent = sbi->vol_flags & (VOLUME_DIRTY | MEDIA_FAILURE);
513	sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
514
515	/* check consistencies */
516	if ((u64)sbi->num_FAT_sectors << p_boot->sect_size_bits <
517	    (u64)sbi->num_clusters * 4) {
518		exfat_err(sb, "bogus fat length");
519		return -EINVAL;
520	}
521
522	if (sbi->data_start_sector <
523	    (u64)sbi->FAT1_start_sector +
524	    (u64)sbi->num_FAT_sectors * p_boot->num_fats) {
525		exfat_err(sb, "bogus data start sector");
526		return -EINVAL;
527	}
528
529	if (sbi->vol_flags & VOLUME_DIRTY)
530		exfat_warn(sb, "Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
531	if (sbi->vol_flags & MEDIA_FAILURE)
532		exfat_warn(sb, "Medium has reported failures. Some data may be lost.");
533
534	/* exFAT file size is limited by a disk volume size */
535	sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) <<
536		sbi->cluster_size_bits;
537
538	/* check logical sector size */
539	if (exfat_calibrate_blocksize(sb, 1 << p_boot->sect_size_bits))
540		return -EIO;
541
542	return 0;
543}
544
545static int exfat_verify_boot_region(struct super_block *sb)
546{
547	struct buffer_head *bh = NULL;
548	u32 chksum = 0;
549	__le32 *p_sig, *p_chksum;
550	int sn, i;
551
552	/* read boot sector sub-regions */
553	for (sn = 0; sn < 11; sn++) {
554		bh = sb_bread(sb, sn);
555		if (!bh)
556			return -EIO;
557
558		if (sn != 0 && sn <= 8) {
559			/* extended boot sector sub-regions */
560			p_sig = (__le32 *)&bh->b_data[sb->s_blocksize - 4];
561			if (le32_to_cpu(*p_sig) != EXBOOT_SIGNATURE)
562				exfat_warn(sb, "Invalid exboot-signature(sector = %d): 0x%08x",
563					   sn, le32_to_cpu(*p_sig));
564		}
565
566		chksum = exfat_calc_chksum32(bh->b_data, sb->s_blocksize,
567			chksum, sn ? CS_DEFAULT : CS_BOOT_SECTOR);
568		brelse(bh);
569	}
570
571	/* boot checksum sub-regions */
572	bh = sb_bread(sb, sn);
573	if (!bh)
574		return -EIO;
575
576	for (i = 0; i < sb->s_blocksize; i += sizeof(u32)) {
577		p_chksum = (__le32 *)&bh->b_data[i];
578		if (le32_to_cpu(*p_chksum) != chksum) {
579			exfat_err(sb, "Invalid boot checksum (boot checksum : 0x%08x, checksum : 0x%08x)",
580				  le32_to_cpu(*p_chksum), chksum);
581			brelse(bh);
582			return -EINVAL;
583		}
584	}
585	brelse(bh);
586	return 0;
587}
588
589/* mount the file system volume */
590static int __exfat_fill_super(struct super_block *sb,
591		struct exfat_chain *root_clu)
592{
593	int ret;
594	struct exfat_sb_info *sbi = EXFAT_SB(sb);
595
596	ret = exfat_read_boot_sector(sb);
597	if (ret) {
598		exfat_err(sb, "failed to read boot sector");
599		goto free_bh;
600	}
601
602	ret = exfat_verify_boot_region(sb);
603	if (ret) {
604		exfat_err(sb, "invalid boot region");
605		goto free_bh;
606	}
607
608	/*
609	 * Call exfat_count_num_cluster() before searching for up-case and
610	 * bitmap directory entries to avoid infinite loop if they are missing
611	 * and the cluster chain includes a loop.
612	 */
613	exfat_chain_set(root_clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
614	ret = exfat_count_num_clusters(sb, root_clu, &root_clu->size);
615	if (ret) {
616		exfat_err(sb, "failed to count the number of clusters in root");
617		goto free_bh;
618	}
619
620	ret = exfat_create_upcase_table(sb);
621	if (ret) {
622		exfat_err(sb, "failed to load upcase table");
623		goto free_bh;
624	}
625
626	ret = exfat_load_bitmap(sb);
627	if (ret) {
628		exfat_err(sb, "failed to load alloc-bitmap");
629		goto free_bh;
630	}
631
632	if (!exfat_test_bitmap(sb, sbi->root_dir)) {
633		exfat_warn(sb, "failed to test first cluster bit of root dir(%u)",
634			   sbi->root_dir);
635		/*
636		 * The first cluster bit of the root directory should never
637		 * be unset except when storage is corrupted. This bit is
638		 * set to allow operations after mount.
639		 */
640		exfat_set_bitmap(sb, sbi->root_dir, false);
641	}
642
643	ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
644	if (ret) {
645		exfat_err(sb, "failed to scan clusters");
646		goto free_alloc_bitmap;
647	}
648
649	return 0;
650
651free_alloc_bitmap:
652	exfat_free_bitmap(sbi);
653free_bh:
654	brelse(sbi->boot_bh);
655	return ret;
656}
657
658static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
659{
660	struct exfat_sb_info *sbi = sb->s_fs_info;
661	struct exfat_mount_options *opts = &sbi->options;
662	struct inode *root_inode;
663	struct exfat_chain root_clu;
664	int err;
665
666	if (opts->allow_utime == (unsigned short)-1)
667		opts->allow_utime = ~opts->fs_dmask & 0022;
668
669	if (opts->discard && !bdev_max_discard_sectors(sb->s_bdev)) {
670		exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
671		opts->discard = 0;
672	}
673
674	sb->s_flags |= SB_NODIRATIME;
675	sb->s_magic = EXFAT_SUPER_MAGIC;
676	sb->s_op = &exfat_sops;
677
678	sb->s_time_gran = 10 * NSEC_PER_MSEC;
679	sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
680	sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
681
682	err = __exfat_fill_super(sb, &root_clu);
683	if (err) {
684		exfat_err(sb, "failed to recognize exfat type");
685		goto check_nls_io;
686	}
687
688	/* set up enough so that it can read an inode */
689	exfat_hash_init(sb);
690
691	if (sbi->options.utf8)
692		set_default_d_op(sb, &exfat_utf8_dentry_ops);
693	else {
694		sbi->nls_io = load_nls(sbi->options.iocharset);
695		if (!sbi->nls_io) {
696			exfat_err(sb, "IO charset %s not found",
697				  sbi->options.iocharset);
698			err = -EINVAL;
699			goto free_table;
700		}
701		set_default_d_op(sb, &exfat_dentry_ops);
702	}
703
704	root_inode = new_inode(sb);
705	if (!root_inode) {
706		exfat_err(sb, "failed to allocate root inode");
707		err = -ENOMEM;
708		goto free_table;
709	}
710
711	root_inode->i_ino = EXFAT_ROOT_INO;
712	inode_set_iversion(root_inode, 1);
713	err = exfat_read_root(root_inode, &root_clu);
714	if (err) {
715		exfat_err(sb, "failed to initialize root inode");
716		goto put_inode;
717	}
718
719	exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
720	insert_inode_hash(root_inode);
721
722	sb->s_root = d_make_root(root_inode);
723	if (!sb->s_root) {
724		exfat_err(sb, "failed to get the root dentry");
725		err = -ENOMEM;
726		goto free_table;
727	}
728
729	return 0;
730
731put_inode:
732	iput(root_inode);
733	sb->s_root = NULL;
734
735free_table:
736	exfat_free_bitmap(sbi);
737	brelse(sbi->boot_bh);
738
739check_nls_io:
740	return err;
741}
742
743static int exfat_get_tree(struct fs_context *fc)
744{
745	return get_tree_bdev(fc, exfat_fill_super);
746}
747
748static void exfat_free_sbi(struct exfat_sb_info *sbi)
749{
750	exfat_free_iocharset(sbi);
751	kfree(sbi);
752}
753
754static void exfat_free(struct fs_context *fc)
755{
756	struct exfat_sb_info *sbi = fc->s_fs_info;
757
758	if (sbi)
759		exfat_free_sbi(sbi);
760}
761
762static int exfat_reconfigure(struct fs_context *fc)
763{
764	struct super_block *sb = fc->root->d_sb;
765	struct exfat_sb_info *remount_sbi = fc->s_fs_info;
766	struct exfat_sb_info *sbi = EXFAT_SB(sb);
767	struct exfat_mount_options *new_opts = &remount_sbi->options;
768	struct exfat_mount_options *cur_opts = &sbi->options;
769
770	fc->sb_flags |= SB_NODIRATIME;
771
772	sync_filesystem(sb);
773	mutex_lock(&sbi->s_lock);
774	exfat_clear_volume_dirty(sb);
775	mutex_unlock(&sbi->s_lock);
776
777	if (new_opts->allow_utime == (unsigned short)-1)
778		new_opts->allow_utime = ~new_opts->fs_dmask & 0022;
779
780	/*
781	 * Since the old settings of these mount options are cached in
782	 * inodes or dentries, they cannot be modified dynamically.
783	 */
784	if (strcmp(new_opts->iocharset, cur_opts->iocharset) ||
785	    new_opts->keep_last_dots != cur_opts->keep_last_dots ||
786	    new_opts->sys_tz != cur_opts->sys_tz ||
787	    new_opts->time_offset != cur_opts->time_offset ||
788	    !uid_eq(new_opts->fs_uid, cur_opts->fs_uid) ||
789	    !gid_eq(new_opts->fs_gid, cur_opts->fs_gid) ||
790	    new_opts->fs_fmask != cur_opts->fs_fmask ||
791	    new_opts->fs_dmask != cur_opts->fs_dmask ||
792	    new_opts->allow_utime != cur_opts->allow_utime)
793		return -EINVAL;
794
795	if (new_opts->discard != cur_opts->discard &&
796	    new_opts->discard &&
797	    !bdev_max_discard_sectors(sb->s_bdev)) {
798		exfat_warn(sb, "remounting with \"discard\" option, but the device does not support discard");
799		return -EINVAL;
800	}
801
802	swap(*cur_opts, *new_opts);
803
804	return 0;
805}
806
807static const struct fs_context_operations exfat_context_ops = {
808	.parse_param	= exfat_parse_param,
809	.get_tree	= exfat_get_tree,
810	.free		= exfat_free,
811	.reconfigure	= exfat_reconfigure,
812};
813
814static int exfat_init_fs_context(struct fs_context *fc)
815{
816	struct exfat_sb_info *sbi;
817
818	sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
819	if (!sbi)
820		return -ENOMEM;
821
822	mutex_init(&sbi->s_lock);
823	mutex_init(&sbi->bitmap_lock);
824	ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
825			DEFAULT_RATELIMIT_BURST);
826
827	if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE && fc->root) {
828		struct super_block *sb = fc->root->d_sb;
829		struct exfat_mount_options *cur_opts = &EXFAT_SB(sb)->options;
830
831		sbi->options.fs_uid = cur_opts->fs_uid;
832		sbi->options.fs_gid = cur_opts->fs_gid;
833		sbi->options.fs_fmask = cur_opts->fs_fmask;
834		sbi->options.fs_dmask = cur_opts->fs_dmask;
835	} else {
836		sbi->options.fs_uid = current_uid();
837		sbi->options.fs_gid = current_gid();
838		sbi->options.fs_fmask = current->fs->umask;
839		sbi->options.fs_dmask = current->fs->umask;
840	}
841
842	sbi->options.allow_utime = -1;
843	sbi->options.errors = EXFAT_ERRORS_RO;
844	exfat_set_iocharset(&sbi->options, exfat_default_iocharset);
845
846	fc->s_fs_info = sbi;
847	fc->ops = &exfat_context_ops;
848	return 0;
849}
850
851static void delayed_free(struct rcu_head *p)
852{
853	struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu);
854
855	unload_nls(sbi->nls_io);
856	exfat_free_upcase_table(sbi);
857	exfat_free_sbi(sbi);
858}
859
860static void exfat_kill_sb(struct super_block *sb)
861{
862	struct exfat_sb_info *sbi = sb->s_fs_info;
863
864	kill_block_super(sb);
865	if (sbi)
866		call_rcu(&sbi->rcu, delayed_free);
867}
868
869static struct file_system_type exfat_fs_type = {
870	.owner			= THIS_MODULE,
871	.name			= "exfat",
872	.init_fs_context	= exfat_init_fs_context,
873	.parameters		= exfat_parameters,
874	.kill_sb		= exfat_kill_sb,
875	.fs_flags		= FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
876};
877
878static void exfat_inode_init_once(void *foo)
879{
880	struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
881
882	spin_lock_init(&ei->cache_lru_lock);
883	ei->nr_caches = 0;
884	ei->cache_valid_id = EXFAT_CACHE_VALID + 1;
885	INIT_LIST_HEAD(&ei->cache_lru);
886	INIT_HLIST_NODE(&ei->i_hash_fat);
887	inode_init_once(&ei->vfs_inode);
888}
889
890static int __init init_exfat_fs(void)
891{
892	int err;
893
894	err = exfat_cache_init();
895	if (err)
896		return err;
897
898	exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
899			sizeof(struct exfat_inode_info),
900			0, SLAB_RECLAIM_ACCOUNT,
901			exfat_inode_init_once);
902	if (!exfat_inode_cachep) {
903		err = -ENOMEM;
904		goto shutdown_cache;
905	}
906
907	err = register_filesystem(&exfat_fs_type);
908	if (err)
909		goto destroy_cache;
910
911	return 0;
912
913destroy_cache:
914	kmem_cache_destroy(exfat_inode_cachep);
915shutdown_cache:
916	exfat_cache_shutdown();
917	return err;
918}
919
920static void __exit exit_exfat_fs(void)
921{
922	/*
923	 * Make sure all delayed rcu free inodes are flushed before we
924	 * destroy cache.
925	 */
926	rcu_barrier();
927	kmem_cache_destroy(exfat_inode_cachep);
928	unregister_filesystem(&exfat_fs_type);
929	exfat_cache_shutdown();
930}
931
932module_init(init_exfat_fs);
933module_exit(exit_exfat_fs);
934
935MODULE_ALIAS_FS("exfat");
936MODULE_LICENSE("GPL");
937MODULE_DESCRIPTION("exFAT filesystem support");
938MODULE_AUTHOR("Samsung Electronics Co., Ltd.");