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
exfat_free_iocharset(struct exfat_sb_info * sbi)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
exfat_put_super(struct super_block * sb)34 static void exfat_put_super(struct super_block *sb)
35 {
36 struct exfat_sb_info *sbi = EXFAT_SB(sb);
37
38 mutex_lock(&sbi->s_lock);
39 exfat_clear_volume_dirty(sb);
40 exfat_free_bitmap(sbi);
41 brelse(sbi->boot_bh);
42 mutex_unlock(&sbi->s_lock);
43 }
44
exfat_statfs(struct dentry * dentry,struct kstatfs * buf)45 static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
46 {
47 struct super_block *sb = dentry->d_sb;
48 struct exfat_sb_info *sbi = EXFAT_SB(sb);
49 unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
50
51 buf->f_type = sb->s_magic;
52 buf->f_bsize = sbi->cluster_size;
53 buf->f_blocks = sbi->num_clusters - 2; /* clu 0 & 1 */
54 buf->f_bfree = buf->f_blocks - sbi->used_clusters;
55 buf->f_bavail = buf->f_bfree;
56 buf->f_fsid = u64_to_fsid(id);
57 /* Unicode utf16 255 characters */
58 buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE;
59 return 0;
60 }
61
exfat_set_vol_flags(struct super_block * sb,unsigned short new_flags)62 static int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flags)
63 {
64 struct exfat_sb_info *sbi = EXFAT_SB(sb);
65 struct boot_sector *p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
66
67 /* retain persistent-flags */
68 new_flags |= sbi->vol_flags_persistent;
69
70 /* flags are not changed */
71 if (sbi->vol_flags == new_flags)
72 return 0;
73
74 sbi->vol_flags = new_flags;
75
76 /* skip updating volume dirty flag,
77 * if this volume has been mounted with read-only
78 */
79 if (sb_rdonly(sb))
80 return 0;
81
82 p_boot->vol_flags = cpu_to_le16(new_flags);
83
84 set_buffer_uptodate(sbi->boot_bh);
85 mark_buffer_dirty(sbi->boot_bh);
86
87 __sync_dirty_buffer(sbi->boot_bh, REQ_SYNC | REQ_FUA | REQ_PREFLUSH);
88
89 return 0;
90 }
91
exfat_set_volume_dirty(struct super_block * sb)92 int exfat_set_volume_dirty(struct super_block *sb)
93 {
94 struct exfat_sb_info *sbi = EXFAT_SB(sb);
95
96 return exfat_set_vol_flags(sb, sbi->vol_flags | VOLUME_DIRTY);
97 }
98
exfat_clear_volume_dirty(struct super_block * sb)99 int exfat_clear_volume_dirty(struct super_block *sb)
100 {
101 struct exfat_sb_info *sbi = EXFAT_SB(sb);
102
103 return exfat_set_vol_flags(sb, sbi->vol_flags & ~VOLUME_DIRTY);
104 }
105
exfat_show_options(struct seq_file * m,struct dentry * root)106 static int exfat_show_options(struct seq_file *m, struct dentry *root)
107 {
108 struct super_block *sb = root->d_sb;
109 struct exfat_sb_info *sbi = EXFAT_SB(sb);
110 struct exfat_mount_options *opts = &sbi->options;
111
112 /* Show partition info */
113 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
114 seq_printf(m, ",uid=%u",
115 from_kuid_munged(&init_user_ns, opts->fs_uid));
116 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
117 seq_printf(m, ",gid=%u",
118 from_kgid_munged(&init_user_ns, opts->fs_gid));
119 seq_printf(m, ",fmask=%04o,dmask=%04o", opts->fs_fmask, opts->fs_dmask);
120 if (opts->allow_utime)
121 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
122 if (opts->utf8)
123 seq_puts(m, ",iocharset=utf8");
124 else if (sbi->nls_io)
125 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
126 if (opts->errors == EXFAT_ERRORS_CONT)
127 seq_puts(m, ",errors=continue");
128 else if (opts->errors == EXFAT_ERRORS_PANIC)
129 seq_puts(m, ",errors=panic");
130 else
131 seq_puts(m, ",errors=remount-ro");
132 if (opts->discard)
133 seq_puts(m, ",discard");
134 if (opts->keep_last_dots)
135 seq_puts(m, ",keep_last_dots");
136 if (opts->sys_tz)
137 seq_puts(m, ",sys_tz");
138 else if (opts->time_offset)
139 seq_printf(m, ",time_offset=%d", opts->time_offset);
140 if (opts->zero_size_dir)
141 seq_puts(m, ",zero_size_dir");
142 return 0;
143 }
144
exfat_force_shutdown(struct super_block * sb,u32 flags)145 int exfat_force_shutdown(struct super_block *sb, u32 flags)
146 {
147 int ret;
148 struct exfat_sb_info *sbi = sb->s_fs_info;
149 struct exfat_mount_options *opts = &sbi->options;
150
151 if (exfat_forced_shutdown(sb))
152 return 0;
153
154 switch (flags) {
155 case EXFAT_GOING_DOWN_DEFAULT:
156 case EXFAT_GOING_DOWN_FULLSYNC:
157 ret = bdev_freeze(sb->s_bdev);
158 if (ret)
159 return ret;
160 bdev_thaw(sb->s_bdev);
161 set_bit(EXFAT_FLAGS_SHUTDOWN, &sbi->s_exfat_flags);
162 break;
163 case EXFAT_GOING_DOWN_NOSYNC:
164 set_bit(EXFAT_FLAGS_SHUTDOWN, &sbi->s_exfat_flags);
165 break;
166 default:
167 return -EINVAL;
168 }
169
170 if (opts->discard)
171 opts->discard = 0;
172 return 0;
173 }
174
exfat_shutdown(struct super_block * sb)175 static void exfat_shutdown(struct super_block *sb)
176 {
177 exfat_force_shutdown(sb, EXFAT_GOING_DOWN_NOSYNC);
178 }
179
exfat_alloc_inode(struct super_block * sb)180 static struct inode *exfat_alloc_inode(struct super_block *sb)
181 {
182 struct exfat_inode_info *ei;
183
184 ei = alloc_inode_sb(sb, exfat_inode_cachep, GFP_NOFS);
185 if (!ei)
186 return NULL;
187
188 init_rwsem(&ei->truncate_lock);
189 return &ei->vfs_inode;
190 }
191
exfat_free_inode(struct inode * inode)192 static void exfat_free_inode(struct inode *inode)
193 {
194 kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
195 }
196
197 static const struct super_operations exfat_sops = {
198 .alloc_inode = exfat_alloc_inode,
199 .free_inode = exfat_free_inode,
200 .write_inode = exfat_write_inode,
201 .evict_inode = exfat_evict_inode,
202 .put_super = exfat_put_super,
203 .statfs = exfat_statfs,
204 .show_options = exfat_show_options,
205 .shutdown = exfat_shutdown,
206 };
207
208 enum {
209 Opt_uid,
210 Opt_gid,
211 Opt_umask,
212 Opt_dmask,
213 Opt_fmask,
214 Opt_allow_utime,
215 Opt_charset,
216 Opt_errors,
217 Opt_discard,
218 Opt_keep_last_dots,
219 Opt_sys_tz,
220 Opt_time_offset,
221 Opt_zero_size_dir,
222
223 /* Deprecated options */
224 Opt_utf8,
225 Opt_debug,
226 Opt_namecase,
227 Opt_codepage,
228 };
229
230 static const struct constant_table exfat_param_enums[] = {
231 { "continue", EXFAT_ERRORS_CONT },
232 { "panic", EXFAT_ERRORS_PANIC },
233 { "remount-ro", EXFAT_ERRORS_RO },
234 {}
235 };
236
237 static const struct fs_parameter_spec exfat_parameters[] = {
238 fsparam_uid("uid", Opt_uid),
239 fsparam_gid("gid", Opt_gid),
240 fsparam_u32oct("umask", Opt_umask),
241 fsparam_u32oct("dmask", Opt_dmask),
242 fsparam_u32oct("fmask", Opt_fmask),
243 fsparam_u32oct("allow_utime", Opt_allow_utime),
244 fsparam_string("iocharset", Opt_charset),
245 fsparam_enum("errors", Opt_errors, exfat_param_enums),
246 fsparam_flag("discard", Opt_discard),
247 fsparam_flag("keep_last_dots", Opt_keep_last_dots),
248 fsparam_flag("sys_tz", Opt_sys_tz),
249 fsparam_s32("time_offset", Opt_time_offset),
250 fsparam_flag("zero_size_dir", Opt_zero_size_dir),
251 __fsparam(NULL, "utf8", Opt_utf8, fs_param_deprecated,
252 NULL),
253 __fsparam(NULL, "debug", Opt_debug, fs_param_deprecated,
254 NULL),
255 __fsparam(fs_param_is_u32, "namecase", Opt_namecase,
256 fs_param_deprecated, NULL),
257 __fsparam(fs_param_is_u32, "codepage", Opt_codepage,
258 fs_param_deprecated, NULL),
259 {}
260 };
261
exfat_parse_param(struct fs_context * fc,struct fs_parameter * param)262 static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
263 {
264 struct exfat_sb_info *sbi = fc->s_fs_info;
265 struct exfat_mount_options *opts = &sbi->options;
266 struct fs_parse_result result;
267 int opt;
268
269 opt = fs_parse(fc, exfat_parameters, param, &result);
270 if (opt < 0)
271 return opt;
272
273 switch (opt) {
274 case Opt_uid:
275 opts->fs_uid = result.uid;
276 break;
277 case Opt_gid:
278 opts->fs_gid = result.gid;
279 break;
280 case Opt_umask:
281 opts->fs_fmask = result.uint_32;
282 opts->fs_dmask = result.uint_32;
283 break;
284 case Opt_dmask:
285 opts->fs_dmask = result.uint_32;
286 break;
287 case Opt_fmask:
288 opts->fs_fmask = result.uint_32;
289 break;
290 case Opt_allow_utime:
291 opts->allow_utime = result.uint_32 & 0022;
292 break;
293 case Opt_charset:
294 exfat_free_iocharset(sbi);
295 opts->iocharset = param->string;
296 param->string = NULL;
297 break;
298 case Opt_errors:
299 opts->errors = result.uint_32;
300 break;
301 case Opt_discard:
302 opts->discard = 1;
303 break;
304 case Opt_keep_last_dots:
305 opts->keep_last_dots = 1;
306 break;
307 case Opt_sys_tz:
308 opts->sys_tz = 1;
309 break;
310 case Opt_time_offset:
311 /*
312 * Make the limit 24 just in case someone invents something
313 * unusual.
314 */
315 if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
316 return -EINVAL;
317 opts->time_offset = result.int_32;
318 break;
319 case Opt_zero_size_dir:
320 opts->zero_size_dir = true;
321 break;
322 case Opt_utf8:
323 case Opt_debug:
324 case Opt_namecase:
325 case Opt_codepage:
326 break;
327 default:
328 return -EINVAL;
329 }
330
331 return 0;
332 }
333
exfat_hash_init(struct super_block * sb)334 static void exfat_hash_init(struct super_block *sb)
335 {
336 struct exfat_sb_info *sbi = EXFAT_SB(sb);
337 int i;
338
339 spin_lock_init(&sbi->inode_hash_lock);
340 for (i = 0; i < EXFAT_HASH_SIZE; i++)
341 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
342 }
343
exfat_read_root(struct inode * inode,struct exfat_chain * root_clu)344 static int exfat_read_root(struct inode *inode, struct exfat_chain *root_clu)
345 {
346 struct super_block *sb = inode->i_sb;
347 struct exfat_sb_info *sbi = EXFAT_SB(sb);
348 struct exfat_inode_info *ei = EXFAT_I(inode);
349 int num_subdirs;
350
351 exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
352 ei->entry = -1;
353 ei->start_clu = sbi->root_dir;
354 ei->flags = ALLOC_FAT_CHAIN;
355 ei->type = TYPE_DIR;
356 ei->version = 0;
357 ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
358 ei->hint_stat.eidx = 0;
359 ei->hint_stat.clu = sbi->root_dir;
360 ei->hint_femp.eidx = EXFAT_HINT_NONE;
361
362 i_size_write(inode, EXFAT_CLU_TO_B(root_clu->size, sbi));
363
364 num_subdirs = exfat_count_dir_entries(sb, root_clu);
365 if (num_subdirs < 0)
366 return -EIO;
367 set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
368
369 inode->i_uid = sbi->options.fs_uid;
370 inode->i_gid = sbi->options.fs_gid;
371 inode_inc_iversion(inode);
372 inode->i_generation = 0;
373 inode->i_mode = exfat_make_mode(sbi, EXFAT_ATTR_SUBDIR, 0777);
374 inode->i_op = &exfat_dir_inode_operations;
375 inode->i_fop = &exfat_dir_operations;
376
377 inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9;
378 ei->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
379
380 exfat_save_attr(inode, EXFAT_ATTR_SUBDIR);
381 ei->i_crtime = simple_inode_init_ts(inode);
382 exfat_truncate_inode_atime(inode);
383 return 0;
384 }
385
exfat_calibrate_blocksize(struct super_block * sb,int logical_sect)386 static int exfat_calibrate_blocksize(struct super_block *sb, int logical_sect)
387 {
388 struct exfat_sb_info *sbi = EXFAT_SB(sb);
389
390 if (!is_power_of_2(logical_sect)) {
391 exfat_err(sb, "bogus logical sector size %u", logical_sect);
392 return -EIO;
393 }
394
395 if (logical_sect < sb->s_blocksize) {
396 exfat_err(sb, "logical sector size too small for device (logical sector size = %u)",
397 logical_sect);
398 return -EIO;
399 }
400
401 if (logical_sect > sb->s_blocksize) {
402 brelse(sbi->boot_bh);
403 sbi->boot_bh = NULL;
404
405 if (!sb_set_blocksize(sb, logical_sect)) {
406 exfat_err(sb, "unable to set blocksize %u",
407 logical_sect);
408 return -EIO;
409 }
410 sbi->boot_bh = sb_bread(sb, 0);
411 if (!sbi->boot_bh) {
412 exfat_err(sb, "unable to read boot sector (logical sector size = %lu)",
413 sb->s_blocksize);
414 return -EIO;
415 }
416 }
417 return 0;
418 }
419
exfat_read_boot_sector(struct super_block * sb)420 static int exfat_read_boot_sector(struct super_block *sb)
421 {
422 struct boot_sector *p_boot;
423 struct exfat_sb_info *sbi = EXFAT_SB(sb);
424
425 /* set block size to read super block */
426 sb_min_blocksize(sb, 512);
427
428 /* read boot sector */
429 sbi->boot_bh = sb_bread(sb, 0);
430 if (!sbi->boot_bh) {
431 exfat_err(sb, "unable to read boot sector");
432 return -EIO;
433 }
434 p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
435
436 /* check the validity of BOOT */
437 if (le16_to_cpu((p_boot->signature)) != BOOT_SIGNATURE) {
438 exfat_err(sb, "invalid boot record signature");
439 return -EINVAL;
440 }
441
442 if (memcmp(p_boot->fs_name, STR_EXFAT, BOOTSEC_FS_NAME_LEN)) {
443 exfat_err(sb, "invalid fs_name"); /* fs_name may unprintable */
444 return -EINVAL;
445 }
446
447 /*
448 * must_be_zero field must be filled with zero to prevent mounting
449 * from FAT volume.
450 */
451 if (memchr_inv(p_boot->must_be_zero, 0, sizeof(p_boot->must_be_zero)))
452 return -EINVAL;
453
454 if (p_boot->num_fats != 1 && p_boot->num_fats != 2) {
455 exfat_err(sb, "bogus number of FAT structure");
456 return -EINVAL;
457 }
458
459 /*
460 * sect_size_bits could be at least 9 and at most 12.
461 */
462 if (p_boot->sect_size_bits < EXFAT_MIN_SECT_SIZE_BITS ||
463 p_boot->sect_size_bits > EXFAT_MAX_SECT_SIZE_BITS) {
464 exfat_err(sb, "bogus sector size bits : %u",
465 p_boot->sect_size_bits);
466 return -EINVAL;
467 }
468
469 /*
470 * sect_per_clus_bits could be at least 0 and at most 25 - sect_size_bits.
471 */
472 if (p_boot->sect_per_clus_bits > EXFAT_MAX_SECT_PER_CLUS_BITS(p_boot)) {
473 exfat_err(sb, "bogus sectors bits per cluster : %u",
474 p_boot->sect_per_clus_bits);
475 return -EINVAL;
476 }
477
478 sbi->sect_per_clus = 1 << p_boot->sect_per_clus_bits;
479 sbi->sect_per_clus_bits = p_boot->sect_per_clus_bits;
480 sbi->cluster_size_bits = p_boot->sect_per_clus_bits +
481 p_boot->sect_size_bits;
482 sbi->cluster_size = 1 << sbi->cluster_size_bits;
483 sbi->num_FAT_sectors = le32_to_cpu(p_boot->fat_length);
484 sbi->FAT1_start_sector = le32_to_cpu(p_boot->fat_offset);
485 sbi->FAT2_start_sector = le32_to_cpu(p_boot->fat_offset);
486 if (p_boot->num_fats == 2)
487 sbi->FAT2_start_sector += sbi->num_FAT_sectors;
488 sbi->data_start_sector = le32_to_cpu(p_boot->clu_offset);
489 sbi->num_sectors = le64_to_cpu(p_boot->vol_length);
490 /* because the cluster index starts with 2 */
491 sbi->num_clusters = le32_to_cpu(p_boot->clu_count) +
492 EXFAT_RESERVED_CLUSTERS;
493
494 sbi->root_dir = le32_to_cpu(p_boot->root_cluster);
495 sbi->dentries_per_clu = 1 <<
496 (sbi->cluster_size_bits - DENTRY_SIZE_BITS);
497
498 sbi->vol_flags = le16_to_cpu(p_boot->vol_flags);
499 sbi->vol_flags_persistent = sbi->vol_flags & (VOLUME_DIRTY | MEDIA_FAILURE);
500 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
501
502 /* check consistencies */
503 if ((u64)sbi->num_FAT_sectors << p_boot->sect_size_bits <
504 (u64)sbi->num_clusters * 4) {
505 exfat_err(sb, "bogus fat length");
506 return -EINVAL;
507 }
508
509 if (sbi->data_start_sector <
510 (u64)sbi->FAT1_start_sector +
511 (u64)sbi->num_FAT_sectors * p_boot->num_fats) {
512 exfat_err(sb, "bogus data start sector");
513 return -EINVAL;
514 }
515
516 if (sbi->vol_flags & VOLUME_DIRTY)
517 exfat_warn(sb, "Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
518 if (sbi->vol_flags & MEDIA_FAILURE)
519 exfat_warn(sb, "Medium has reported failures. Some data may be lost.");
520
521 /* exFAT file size is limited by a disk volume size */
522 sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) <<
523 sbi->cluster_size_bits;
524
525 /* check logical sector size */
526 if (exfat_calibrate_blocksize(sb, 1 << p_boot->sect_size_bits))
527 return -EIO;
528
529 return 0;
530 }
531
exfat_verify_boot_region(struct super_block * sb)532 static int exfat_verify_boot_region(struct super_block *sb)
533 {
534 struct buffer_head *bh = NULL;
535 u32 chksum = 0;
536 __le32 *p_sig, *p_chksum;
537 int sn, i;
538
539 /* read boot sector sub-regions */
540 for (sn = 0; sn < 11; sn++) {
541 bh = sb_bread(sb, sn);
542 if (!bh)
543 return -EIO;
544
545 if (sn != 0 && sn <= 8) {
546 /* extended boot sector sub-regions */
547 p_sig = (__le32 *)&bh->b_data[sb->s_blocksize - 4];
548 if (le32_to_cpu(*p_sig) != EXBOOT_SIGNATURE)
549 exfat_warn(sb, "Invalid exboot-signature(sector = %d): 0x%08x",
550 sn, le32_to_cpu(*p_sig));
551 }
552
553 chksum = exfat_calc_chksum32(bh->b_data, sb->s_blocksize,
554 chksum, sn ? CS_DEFAULT : CS_BOOT_SECTOR);
555 brelse(bh);
556 }
557
558 /* boot checksum sub-regions */
559 bh = sb_bread(sb, sn);
560 if (!bh)
561 return -EIO;
562
563 for (i = 0; i < sb->s_blocksize; i += sizeof(u32)) {
564 p_chksum = (__le32 *)&bh->b_data[i];
565 if (le32_to_cpu(*p_chksum) != chksum) {
566 exfat_err(sb, "Invalid boot checksum (boot checksum : 0x%08x, checksum : 0x%08x)",
567 le32_to_cpu(*p_chksum), chksum);
568 brelse(bh);
569 return -EINVAL;
570 }
571 }
572 brelse(bh);
573 return 0;
574 }
575
576 /* mount the file system volume */
__exfat_fill_super(struct super_block * sb,struct exfat_chain * root_clu)577 static int __exfat_fill_super(struct super_block *sb,
578 struct exfat_chain *root_clu)
579 {
580 int ret;
581 struct exfat_sb_info *sbi = EXFAT_SB(sb);
582
583 ret = exfat_read_boot_sector(sb);
584 if (ret) {
585 exfat_err(sb, "failed to read boot sector");
586 goto free_bh;
587 }
588
589 ret = exfat_verify_boot_region(sb);
590 if (ret) {
591 exfat_err(sb, "invalid boot region");
592 goto free_bh;
593 }
594
595 /*
596 * Call exfat_count_num_cluster() before searching for up-case and
597 * bitmap directory entries to avoid infinite loop if they are missing
598 * and the cluster chain includes a loop.
599 */
600 exfat_chain_set(root_clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
601 ret = exfat_count_num_clusters(sb, root_clu, &root_clu->size);
602 if (ret) {
603 exfat_err(sb, "failed to count the number of clusters in root");
604 goto free_bh;
605 }
606
607 ret = exfat_create_upcase_table(sb);
608 if (ret) {
609 exfat_err(sb, "failed to load upcase table");
610 goto free_bh;
611 }
612
613 ret = exfat_load_bitmap(sb);
614 if (ret) {
615 exfat_err(sb, "failed to load alloc-bitmap");
616 goto free_bh;
617 }
618
619 ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
620 if (ret) {
621 exfat_err(sb, "failed to scan clusters");
622 goto free_alloc_bitmap;
623 }
624
625 return 0;
626
627 free_alloc_bitmap:
628 exfat_free_bitmap(sbi);
629 free_bh:
630 brelse(sbi->boot_bh);
631 return ret;
632 }
633
exfat_fill_super(struct super_block * sb,struct fs_context * fc)634 static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
635 {
636 struct exfat_sb_info *sbi = sb->s_fs_info;
637 struct exfat_mount_options *opts = &sbi->options;
638 struct inode *root_inode;
639 struct exfat_chain root_clu;
640 int err;
641
642 if (opts->allow_utime == (unsigned short)-1)
643 opts->allow_utime = ~opts->fs_dmask & 0022;
644
645 if (opts->discard && !bdev_max_discard_sectors(sb->s_bdev)) {
646 exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
647 opts->discard = 0;
648 }
649
650 sb->s_flags |= SB_NODIRATIME;
651 sb->s_magic = EXFAT_SUPER_MAGIC;
652 sb->s_op = &exfat_sops;
653
654 sb->s_time_gran = 10 * NSEC_PER_MSEC;
655 sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
656 sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
657
658 err = __exfat_fill_super(sb, &root_clu);
659 if (err) {
660 exfat_err(sb, "failed to recognize exfat type");
661 goto check_nls_io;
662 }
663
664 /* set up enough so that it can read an inode */
665 exfat_hash_init(sb);
666
667 if (!strcmp(sbi->options.iocharset, "utf8"))
668 opts->utf8 = 1;
669 else {
670 sbi->nls_io = load_nls(sbi->options.iocharset);
671 if (!sbi->nls_io) {
672 exfat_err(sb, "IO charset %s not found",
673 sbi->options.iocharset);
674 err = -EINVAL;
675 goto free_table;
676 }
677 }
678
679 if (sbi->options.utf8)
680 set_default_d_op(sb, &exfat_utf8_dentry_ops);
681 else
682 set_default_d_op(sb, &exfat_dentry_ops);
683
684 root_inode = new_inode(sb);
685 if (!root_inode) {
686 exfat_err(sb, "failed to allocate root inode");
687 err = -ENOMEM;
688 goto free_table;
689 }
690
691 root_inode->i_ino = EXFAT_ROOT_INO;
692 inode_set_iversion(root_inode, 1);
693 err = exfat_read_root(root_inode, &root_clu);
694 if (err) {
695 exfat_err(sb, "failed to initialize root inode");
696 goto put_inode;
697 }
698
699 exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
700 insert_inode_hash(root_inode);
701
702 sb->s_root = d_make_root(root_inode);
703 if (!sb->s_root) {
704 exfat_err(sb, "failed to get the root dentry");
705 err = -ENOMEM;
706 goto free_table;
707 }
708
709 return 0;
710
711 put_inode:
712 iput(root_inode);
713 sb->s_root = NULL;
714
715 free_table:
716 exfat_free_bitmap(sbi);
717 brelse(sbi->boot_bh);
718
719 check_nls_io:
720 return err;
721 }
722
exfat_get_tree(struct fs_context * fc)723 static int exfat_get_tree(struct fs_context *fc)
724 {
725 return get_tree_bdev(fc, exfat_fill_super);
726 }
727
exfat_free_sbi(struct exfat_sb_info * sbi)728 static void exfat_free_sbi(struct exfat_sb_info *sbi)
729 {
730 exfat_free_iocharset(sbi);
731 kfree(sbi);
732 }
733
exfat_free(struct fs_context * fc)734 static void exfat_free(struct fs_context *fc)
735 {
736 struct exfat_sb_info *sbi = fc->s_fs_info;
737
738 if (sbi)
739 exfat_free_sbi(sbi);
740 }
741
exfat_reconfigure(struct fs_context * fc)742 static int exfat_reconfigure(struct fs_context *fc)
743 {
744 struct super_block *sb = fc->root->d_sb;
745 fc->sb_flags |= SB_NODIRATIME;
746
747 sync_filesystem(sb);
748 mutex_lock(&EXFAT_SB(sb)->s_lock);
749 exfat_clear_volume_dirty(sb);
750 mutex_unlock(&EXFAT_SB(sb)->s_lock);
751
752 return 0;
753 }
754
755 static const struct fs_context_operations exfat_context_ops = {
756 .parse_param = exfat_parse_param,
757 .get_tree = exfat_get_tree,
758 .free = exfat_free,
759 .reconfigure = exfat_reconfigure,
760 };
761
exfat_init_fs_context(struct fs_context * fc)762 static int exfat_init_fs_context(struct fs_context *fc)
763 {
764 struct exfat_sb_info *sbi;
765
766 sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
767 if (!sbi)
768 return -ENOMEM;
769
770 mutex_init(&sbi->s_lock);
771 mutex_init(&sbi->bitmap_lock);
772 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
773 DEFAULT_RATELIMIT_BURST);
774
775 sbi->options.fs_uid = current_uid();
776 sbi->options.fs_gid = current_gid();
777 sbi->options.fs_fmask = current->fs->umask;
778 sbi->options.fs_dmask = current->fs->umask;
779 sbi->options.allow_utime = -1;
780 sbi->options.iocharset = exfat_default_iocharset;
781 sbi->options.errors = EXFAT_ERRORS_RO;
782
783 fc->s_fs_info = sbi;
784 fc->ops = &exfat_context_ops;
785 return 0;
786 }
787
delayed_free(struct rcu_head * p)788 static void delayed_free(struct rcu_head *p)
789 {
790 struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu);
791
792 unload_nls(sbi->nls_io);
793 exfat_free_upcase_table(sbi);
794 exfat_free_sbi(sbi);
795 }
796
exfat_kill_sb(struct super_block * sb)797 static void exfat_kill_sb(struct super_block *sb)
798 {
799 struct exfat_sb_info *sbi = sb->s_fs_info;
800
801 kill_block_super(sb);
802 if (sbi)
803 call_rcu(&sbi->rcu, delayed_free);
804 }
805
806 static struct file_system_type exfat_fs_type = {
807 .owner = THIS_MODULE,
808 .name = "exfat",
809 .init_fs_context = exfat_init_fs_context,
810 .parameters = exfat_parameters,
811 .kill_sb = exfat_kill_sb,
812 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
813 };
814
exfat_inode_init_once(void * foo)815 static void exfat_inode_init_once(void *foo)
816 {
817 struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
818
819 spin_lock_init(&ei->cache_lru_lock);
820 ei->nr_caches = 0;
821 ei->cache_valid_id = EXFAT_CACHE_VALID + 1;
822 INIT_LIST_HEAD(&ei->cache_lru);
823 INIT_HLIST_NODE(&ei->i_hash_fat);
824 inode_init_once(&ei->vfs_inode);
825 }
826
init_exfat_fs(void)827 static int __init init_exfat_fs(void)
828 {
829 int err;
830
831 err = exfat_cache_init();
832 if (err)
833 return err;
834
835 exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
836 sizeof(struct exfat_inode_info),
837 0, SLAB_RECLAIM_ACCOUNT,
838 exfat_inode_init_once);
839 if (!exfat_inode_cachep) {
840 err = -ENOMEM;
841 goto shutdown_cache;
842 }
843
844 err = register_filesystem(&exfat_fs_type);
845 if (err)
846 goto destroy_cache;
847
848 return 0;
849
850 destroy_cache:
851 kmem_cache_destroy(exfat_inode_cachep);
852 shutdown_cache:
853 exfat_cache_shutdown();
854 return err;
855 }
856
exit_exfat_fs(void)857 static void __exit exit_exfat_fs(void)
858 {
859 /*
860 * Make sure all delayed rcu free inodes are flushed before we
861 * destroy cache.
862 */
863 rcu_barrier();
864 kmem_cache_destroy(exfat_inode_cachep);
865 unregister_filesystem(&exfat_fs_type);
866 exfat_cache_shutdown();
867 }
868
869 module_init(init_exfat_fs);
870 module_exit(exit_exfat_fs);
871
872 MODULE_ALIAS_FS("exfat");
873 MODULE_LICENSE("GPL");
874 MODULE_DESCRIPTION("exFAT filesystem support");
875 MODULE_AUTHOR("Samsung Electronics Co., Ltd.");
876