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