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 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
exfat_verify_boot_region(struct super_block * sb)545 static 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 */
__exfat_fill_super(struct super_block * sb,struct exfat_chain * root_clu)590 static 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 ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
633 if (ret) {
634 exfat_err(sb, "failed to scan clusters");
635 goto free_alloc_bitmap;
636 }
637
638 return 0;
639
640 free_alloc_bitmap:
641 exfat_free_bitmap(sbi);
642 free_bh:
643 brelse(sbi->boot_bh);
644 return ret;
645 }
646
exfat_fill_super(struct super_block * sb,struct fs_context * fc)647 static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
648 {
649 struct exfat_sb_info *sbi = sb->s_fs_info;
650 struct exfat_mount_options *opts = &sbi->options;
651 struct inode *root_inode;
652 struct exfat_chain root_clu;
653 int err;
654
655 if (opts->allow_utime == (unsigned short)-1)
656 opts->allow_utime = ~opts->fs_dmask & 0022;
657
658 if (opts->discard && !bdev_max_discard_sectors(sb->s_bdev)) {
659 exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
660 opts->discard = 0;
661 }
662
663 sb->s_flags |= SB_NODIRATIME;
664 sb->s_magic = EXFAT_SUPER_MAGIC;
665 sb->s_op = &exfat_sops;
666
667 sb->s_time_gran = 10 * NSEC_PER_MSEC;
668 sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
669 sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
670
671 err = __exfat_fill_super(sb, &root_clu);
672 if (err) {
673 exfat_err(sb, "failed to recognize exfat type");
674 goto check_nls_io;
675 }
676
677 /* set up enough so that it can read an inode */
678 exfat_hash_init(sb);
679
680 if (sbi->options.utf8)
681 set_default_d_op(sb, &exfat_utf8_dentry_ops);
682 else {
683 sbi->nls_io = load_nls(sbi->options.iocharset);
684 if (!sbi->nls_io) {
685 exfat_err(sb, "IO charset %s not found",
686 sbi->options.iocharset);
687 err = -EINVAL;
688 goto free_table;
689 }
690 set_default_d_op(sb, &exfat_dentry_ops);
691 }
692
693 root_inode = new_inode(sb);
694 if (!root_inode) {
695 exfat_err(sb, "failed to allocate root inode");
696 err = -ENOMEM;
697 goto free_table;
698 }
699
700 root_inode->i_ino = EXFAT_ROOT_INO;
701 inode_set_iversion(root_inode, 1);
702 err = exfat_read_root(root_inode, &root_clu);
703 if (err) {
704 exfat_err(sb, "failed to initialize root inode");
705 goto put_inode;
706 }
707
708 exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
709 insert_inode_hash(root_inode);
710
711 sb->s_root = d_make_root(root_inode);
712 if (!sb->s_root) {
713 exfat_err(sb, "failed to get the root dentry");
714 err = -ENOMEM;
715 goto free_table;
716 }
717
718 return 0;
719
720 put_inode:
721 iput(root_inode);
722 sb->s_root = NULL;
723
724 free_table:
725 exfat_free_bitmap(sbi);
726 brelse(sbi->boot_bh);
727
728 check_nls_io:
729 return err;
730 }
731
exfat_get_tree(struct fs_context * fc)732 static int exfat_get_tree(struct fs_context *fc)
733 {
734 return get_tree_bdev(fc, exfat_fill_super);
735 }
736
exfat_free_sbi(struct exfat_sb_info * sbi)737 static void exfat_free_sbi(struct exfat_sb_info *sbi)
738 {
739 exfat_free_iocharset(sbi);
740 kfree(sbi);
741 }
742
exfat_free(struct fs_context * fc)743 static void exfat_free(struct fs_context *fc)
744 {
745 struct exfat_sb_info *sbi = fc->s_fs_info;
746
747 if (sbi)
748 exfat_free_sbi(sbi);
749 }
750
exfat_reconfigure(struct fs_context * fc)751 static int exfat_reconfigure(struct fs_context *fc)
752 {
753 struct super_block *sb = fc->root->d_sb;
754 struct exfat_sb_info *remount_sbi = fc->s_fs_info;
755 struct exfat_sb_info *sbi = EXFAT_SB(sb);
756 struct exfat_mount_options *new_opts = &remount_sbi->options;
757 struct exfat_mount_options *cur_opts = &sbi->options;
758
759 fc->sb_flags |= SB_NODIRATIME;
760
761 sync_filesystem(sb);
762 mutex_lock(&sbi->s_lock);
763 exfat_clear_volume_dirty(sb);
764 mutex_unlock(&sbi->s_lock);
765
766 if (new_opts->allow_utime == (unsigned short)-1)
767 new_opts->allow_utime = ~new_opts->fs_dmask & 0022;
768
769 /*
770 * Since the old settings of these mount options are cached in
771 * inodes or dentries, they cannot be modified dynamically.
772 */
773 if (strcmp(new_opts->iocharset, cur_opts->iocharset) ||
774 new_opts->keep_last_dots != cur_opts->keep_last_dots ||
775 new_opts->sys_tz != cur_opts->sys_tz ||
776 new_opts->time_offset != cur_opts->time_offset ||
777 !uid_eq(new_opts->fs_uid, cur_opts->fs_uid) ||
778 !gid_eq(new_opts->fs_gid, cur_opts->fs_gid) ||
779 new_opts->fs_fmask != cur_opts->fs_fmask ||
780 new_opts->fs_dmask != cur_opts->fs_dmask ||
781 new_opts->allow_utime != cur_opts->allow_utime)
782 return -EINVAL;
783
784 if (new_opts->discard != cur_opts->discard &&
785 new_opts->discard &&
786 !bdev_max_discard_sectors(sb->s_bdev)) {
787 exfat_warn(sb, "remounting with \"discard\" option, but the device does not support discard");
788 return -EINVAL;
789 }
790
791 swap(*cur_opts, *new_opts);
792
793 return 0;
794 }
795
796 static const struct fs_context_operations exfat_context_ops = {
797 .parse_param = exfat_parse_param,
798 .get_tree = exfat_get_tree,
799 .free = exfat_free,
800 .reconfigure = exfat_reconfigure,
801 };
802
exfat_init_fs_context(struct fs_context * fc)803 static int exfat_init_fs_context(struct fs_context *fc)
804 {
805 struct exfat_sb_info *sbi;
806
807 sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
808 if (!sbi)
809 return -ENOMEM;
810
811 mutex_init(&sbi->s_lock);
812 mutex_init(&sbi->bitmap_lock);
813 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
814 DEFAULT_RATELIMIT_BURST);
815
816 sbi->options.fs_uid = current_uid();
817 sbi->options.fs_gid = current_gid();
818 sbi->options.fs_fmask = current->fs->umask;
819 sbi->options.fs_dmask = current->fs->umask;
820 sbi->options.allow_utime = -1;
821 sbi->options.errors = EXFAT_ERRORS_RO;
822 exfat_set_iocharset(&sbi->options, exfat_default_iocharset);
823
824 fc->s_fs_info = sbi;
825 fc->ops = &exfat_context_ops;
826 return 0;
827 }
828
delayed_free(struct rcu_head * p)829 static void delayed_free(struct rcu_head *p)
830 {
831 struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu);
832
833 unload_nls(sbi->nls_io);
834 exfat_free_upcase_table(sbi);
835 exfat_free_sbi(sbi);
836 }
837
exfat_kill_sb(struct super_block * sb)838 static void exfat_kill_sb(struct super_block *sb)
839 {
840 struct exfat_sb_info *sbi = sb->s_fs_info;
841
842 kill_block_super(sb);
843 if (sbi)
844 call_rcu(&sbi->rcu, delayed_free);
845 }
846
847 static struct file_system_type exfat_fs_type = {
848 .owner = THIS_MODULE,
849 .name = "exfat",
850 .init_fs_context = exfat_init_fs_context,
851 .parameters = exfat_parameters,
852 .kill_sb = exfat_kill_sb,
853 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
854 };
855
exfat_inode_init_once(void * foo)856 static void exfat_inode_init_once(void *foo)
857 {
858 struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
859
860 spin_lock_init(&ei->cache_lru_lock);
861 ei->nr_caches = 0;
862 ei->cache_valid_id = EXFAT_CACHE_VALID + 1;
863 INIT_LIST_HEAD(&ei->cache_lru);
864 INIT_HLIST_NODE(&ei->i_hash_fat);
865 inode_init_once(&ei->vfs_inode);
866 }
867
init_exfat_fs(void)868 static int __init init_exfat_fs(void)
869 {
870 int err;
871
872 err = exfat_cache_init();
873 if (err)
874 return err;
875
876 exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
877 sizeof(struct exfat_inode_info),
878 0, SLAB_RECLAIM_ACCOUNT,
879 exfat_inode_init_once);
880 if (!exfat_inode_cachep) {
881 err = -ENOMEM;
882 goto shutdown_cache;
883 }
884
885 err = register_filesystem(&exfat_fs_type);
886 if (err)
887 goto destroy_cache;
888
889 return 0;
890
891 destroy_cache:
892 kmem_cache_destroy(exfat_inode_cachep);
893 shutdown_cache:
894 exfat_cache_shutdown();
895 return err;
896 }
897
exit_exfat_fs(void)898 static void __exit exit_exfat_fs(void)
899 {
900 /*
901 * Make sure all delayed rcu free inodes are flushed before we
902 * destroy cache.
903 */
904 rcu_barrier();
905 kmem_cache_destroy(exfat_inode_cachep);
906 unregister_filesystem(&exfat_fs_type);
907 exfat_cache_shutdown();
908 }
909
910 module_init(init_exfat_fs);
911 module_exit(exit_exfat_fs);
912
913 MODULE_ALIAS_FS("exfat");
914 MODULE_LICENSE("GPL");
915 MODULE_DESCRIPTION("exFAT filesystem support");
916 MODULE_AUTHOR("Samsung Electronics Co., Ltd.");
917