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_free_bitmap(sbi);
40 brelse(sbi->boot_bh);
41 mutex_unlock(&sbi->s_lock);
42 }
43
exfat_sync_fs(struct super_block * sb,int wait)44 static int exfat_sync_fs(struct super_block *sb, int wait)
45 {
46 struct exfat_sb_info *sbi = EXFAT_SB(sb);
47 int err = 0;
48
49 if (unlikely(exfat_forced_shutdown(sb)))
50 return 0;
51
52 if (!wait)
53 return 0;
54
55 /* If there are some dirty buffers in the bdev inode */
56 mutex_lock(&sbi->s_lock);
57 sync_blockdev(sb->s_bdev);
58 if (exfat_clear_volume_dirty(sb))
59 err = -EIO;
60 mutex_unlock(&sbi->s_lock);
61 return err;
62 }
63
exfat_statfs(struct dentry * dentry,struct kstatfs * buf)64 static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
65 {
66 struct super_block *sb = dentry->d_sb;
67 struct exfat_sb_info *sbi = EXFAT_SB(sb);
68 unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
69
70 if (sbi->used_clusters == EXFAT_CLUSTERS_UNTRACKED) {
71 mutex_lock(&sbi->s_lock);
72 if (exfat_count_used_clusters(sb, &sbi->used_clusters)) {
73 mutex_unlock(&sbi->s_lock);
74 return -EIO;
75 }
76 mutex_unlock(&sbi->s_lock);
77 }
78
79 buf->f_type = sb->s_magic;
80 buf->f_bsize = sbi->cluster_size;
81 buf->f_blocks = sbi->num_clusters - 2; /* clu 0 & 1 */
82 buf->f_bfree = buf->f_blocks - sbi->used_clusters;
83 buf->f_bavail = buf->f_bfree;
84 buf->f_fsid = u64_to_fsid(id);
85 /* Unicode utf16 255 characters */
86 buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE;
87 return 0;
88 }
89
exfat_set_vol_flags(struct super_block * sb,unsigned short new_flags)90 static int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flags)
91 {
92 struct exfat_sb_info *sbi = EXFAT_SB(sb);
93 struct boot_sector *p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
94
95 /* retain persistent-flags */
96 new_flags |= sbi->vol_flags_persistent;
97
98 /* flags are not changed */
99 if (sbi->vol_flags == new_flags)
100 return 0;
101
102 sbi->vol_flags = new_flags;
103
104 /* skip updating volume dirty flag,
105 * if this volume has been mounted with read-only
106 */
107 if (sb_rdonly(sb))
108 return 0;
109
110 p_boot->vol_flags = cpu_to_le16(new_flags);
111
112 set_buffer_uptodate(sbi->boot_bh);
113 mark_buffer_dirty(sbi->boot_bh);
114
115 __sync_dirty_buffer(sbi->boot_bh, REQ_SYNC | REQ_FUA | REQ_PREFLUSH);
116
117 return 0;
118 }
119
exfat_set_volume_dirty(struct super_block * sb)120 int exfat_set_volume_dirty(struct super_block *sb)
121 {
122 struct exfat_sb_info *sbi = EXFAT_SB(sb);
123
124 return exfat_set_vol_flags(sb, sbi->vol_flags | VOLUME_DIRTY);
125 }
126
exfat_clear_volume_dirty(struct super_block * sb)127 int exfat_clear_volume_dirty(struct super_block *sb)
128 {
129 struct exfat_sb_info *sbi = EXFAT_SB(sb);
130
131 return exfat_set_vol_flags(sb, sbi->vol_flags & ~VOLUME_DIRTY);
132 }
133
exfat_show_options(struct seq_file * m,struct dentry * root)134 static int exfat_show_options(struct seq_file *m, struct dentry *root)
135 {
136 struct super_block *sb = root->d_sb;
137 struct exfat_sb_info *sbi = EXFAT_SB(sb);
138 struct exfat_mount_options *opts = &sbi->options;
139
140 /* Show partition info */
141 if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
142 seq_printf(m, ",uid=%u",
143 from_kuid_munged(&init_user_ns, opts->fs_uid));
144 if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
145 seq_printf(m, ",gid=%u",
146 from_kgid_munged(&init_user_ns, opts->fs_gid));
147 seq_printf(m, ",fmask=%04o,dmask=%04o", opts->fs_fmask, opts->fs_dmask);
148 if (opts->allow_utime)
149 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
150 if (opts->utf8)
151 seq_puts(m, ",iocharset=utf8");
152 else if (sbi->nls_io)
153 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
154 if (opts->errors == EXFAT_ERRORS_CONT)
155 seq_puts(m, ",errors=continue");
156 else if (opts->errors == EXFAT_ERRORS_PANIC)
157 seq_puts(m, ",errors=panic");
158 else
159 seq_puts(m, ",errors=remount-ro");
160 if (opts->discard)
161 seq_puts(m, ",discard");
162 if (opts->keep_last_dots)
163 seq_puts(m, ",keep_last_dots");
164 if (opts->sys_tz)
165 seq_puts(m, ",sys_tz");
166 else if (opts->time_offset)
167 seq_printf(m, ",time_offset=%d", opts->time_offset);
168 if (opts->zero_size_dir)
169 seq_puts(m, ",zero_size_dir");
170 return 0;
171 }
172
exfat_force_shutdown(struct super_block * sb,u32 flags)173 int exfat_force_shutdown(struct super_block *sb, u32 flags)
174 {
175 int ret;
176 struct exfat_sb_info *sbi = sb->s_fs_info;
177 struct exfat_mount_options *opts = &sbi->options;
178
179 if (exfat_forced_shutdown(sb))
180 return 0;
181
182 switch (flags) {
183 case EXFAT_GOING_DOWN_DEFAULT:
184 case EXFAT_GOING_DOWN_FULLSYNC:
185 ret = bdev_freeze(sb->s_bdev);
186 if (ret)
187 return ret;
188 bdev_thaw(sb->s_bdev);
189 set_bit(EXFAT_FLAGS_SHUTDOWN, &sbi->s_exfat_flags);
190 break;
191 case EXFAT_GOING_DOWN_NOSYNC:
192 set_bit(EXFAT_FLAGS_SHUTDOWN, &sbi->s_exfat_flags);
193 break;
194 default:
195 return -EINVAL;
196 }
197
198 if (opts->discard)
199 opts->discard = 0;
200 return 0;
201 }
202
exfat_shutdown(struct super_block * sb)203 static void exfat_shutdown(struct super_block *sb)
204 {
205 exfat_force_shutdown(sb, EXFAT_GOING_DOWN_NOSYNC);
206 }
207
exfat_alloc_inode(struct super_block * sb)208 static struct inode *exfat_alloc_inode(struct super_block *sb)
209 {
210 struct exfat_inode_info *ei;
211
212 ei = alloc_inode_sb(sb, exfat_inode_cachep, GFP_NOFS);
213 if (!ei)
214 return NULL;
215
216 init_rwsem(&ei->truncate_lock);
217 return &ei->vfs_inode;
218 }
219
exfat_free_inode(struct inode * inode)220 static void exfat_free_inode(struct inode *inode)
221 {
222 kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
223 }
224
225 static const struct super_operations exfat_sops = {
226 .alloc_inode = exfat_alloc_inode,
227 .free_inode = exfat_free_inode,
228 .write_inode = exfat_write_inode,
229 .evict_inode = exfat_evict_inode,
230 .put_super = exfat_put_super,
231 .sync_fs = exfat_sync_fs,
232 .statfs = exfat_statfs,
233 .show_options = exfat_show_options,
234 .shutdown = exfat_shutdown,
235 };
236
237 enum {
238 Opt_uid,
239 Opt_gid,
240 Opt_umask,
241 Opt_dmask,
242 Opt_fmask,
243 Opt_allow_utime,
244 Opt_charset,
245 Opt_errors,
246 Opt_discard,
247 Opt_keep_last_dots,
248 Opt_sys_tz,
249 Opt_time_offset,
250 Opt_zero_size_dir,
251
252 /* Deprecated options */
253 Opt_utf8,
254 Opt_debug,
255 Opt_namecase,
256 Opt_codepage,
257 };
258
259 static const struct constant_table exfat_param_enums[] = {
260 { "continue", EXFAT_ERRORS_CONT },
261 { "panic", EXFAT_ERRORS_PANIC },
262 { "remount-ro", EXFAT_ERRORS_RO },
263 {}
264 };
265
266 static const struct fs_parameter_spec exfat_parameters[] = {
267 fsparam_uid("uid", Opt_uid),
268 fsparam_gid("gid", Opt_gid),
269 fsparam_u32oct("umask", Opt_umask),
270 fsparam_u32oct("dmask", Opt_dmask),
271 fsparam_u32oct("fmask", Opt_fmask),
272 fsparam_u32oct("allow_utime", Opt_allow_utime),
273 fsparam_string("iocharset", Opt_charset),
274 fsparam_enum("errors", Opt_errors, exfat_param_enums),
275 fsparam_flag("discard", Opt_discard),
276 fsparam_flag("keep_last_dots", Opt_keep_last_dots),
277 fsparam_flag("sys_tz", Opt_sys_tz),
278 fsparam_s32("time_offset", Opt_time_offset),
279 fsparam_flag("zero_size_dir", Opt_zero_size_dir),
280 __fsparam(NULL, "utf8", Opt_utf8, fs_param_deprecated,
281 NULL),
282 __fsparam(NULL, "debug", Opt_debug, fs_param_deprecated,
283 NULL),
284 __fsparam(fs_param_is_u32, "namecase", Opt_namecase,
285 fs_param_deprecated, NULL),
286 __fsparam(fs_param_is_u32, "codepage", Opt_codepage,
287 fs_param_deprecated, NULL),
288 {}
289 };
290
exfat_parse_param(struct fs_context * fc,struct fs_parameter * param)291 static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
292 {
293 struct exfat_sb_info *sbi = fc->s_fs_info;
294 struct exfat_mount_options *opts = &sbi->options;
295 struct fs_parse_result result;
296 int opt;
297
298 opt = fs_parse(fc, exfat_parameters, param, &result);
299 if (opt < 0)
300 return opt;
301
302 switch (opt) {
303 case Opt_uid:
304 opts->fs_uid = result.uid;
305 break;
306 case Opt_gid:
307 opts->fs_gid = result.gid;
308 break;
309 case Opt_umask:
310 opts->fs_fmask = result.uint_32;
311 opts->fs_dmask = result.uint_32;
312 break;
313 case Opt_dmask:
314 opts->fs_dmask = result.uint_32;
315 break;
316 case Opt_fmask:
317 opts->fs_fmask = result.uint_32;
318 break;
319 case Opt_allow_utime:
320 opts->allow_utime = result.uint_32 & 0022;
321 break;
322 case Opt_charset:
323 exfat_free_iocharset(sbi);
324 opts->iocharset = param->string;
325 param->string = NULL;
326 break;
327 case Opt_errors:
328 opts->errors = result.uint_32;
329 break;
330 case Opt_discard:
331 opts->discard = 1;
332 break;
333 case Opt_keep_last_dots:
334 opts->keep_last_dots = 1;
335 break;
336 case Opt_sys_tz:
337 opts->sys_tz = 1;
338 break;
339 case Opt_time_offset:
340 /*
341 * Make the limit 24 just in case someone invents something
342 * unusual.
343 */
344 if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
345 return -EINVAL;
346 opts->time_offset = result.int_32;
347 break;
348 case Opt_zero_size_dir:
349 opts->zero_size_dir = true;
350 break;
351 case Opt_utf8:
352 case Opt_debug:
353 case Opt_namecase:
354 case Opt_codepage:
355 break;
356 default:
357 return -EINVAL;
358 }
359
360 return 0;
361 }
362
exfat_hash_init(struct super_block * sb)363 static void exfat_hash_init(struct super_block *sb)
364 {
365 struct exfat_sb_info *sbi = EXFAT_SB(sb);
366 int i;
367
368 spin_lock_init(&sbi->inode_hash_lock);
369 for (i = 0; i < EXFAT_HASH_SIZE; i++)
370 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
371 }
372
exfat_read_root(struct inode * inode,struct exfat_chain * root_clu)373 static int exfat_read_root(struct inode *inode, struct exfat_chain *root_clu)
374 {
375 struct super_block *sb = inode->i_sb;
376 struct exfat_sb_info *sbi = EXFAT_SB(sb);
377 struct exfat_inode_info *ei = EXFAT_I(inode);
378 int num_subdirs;
379
380 exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
381 ei->entry = -1;
382 ei->start_clu = sbi->root_dir;
383 ei->flags = ALLOC_FAT_CHAIN;
384 ei->type = TYPE_DIR;
385 ei->version = 0;
386 ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
387 ei->hint_stat.eidx = 0;
388 ei->hint_stat.clu = sbi->root_dir;
389 ei->hint_femp.eidx = EXFAT_HINT_NONE;
390
391 i_size_write(inode, EXFAT_CLU_TO_B(root_clu->size, sbi));
392
393 num_subdirs = exfat_count_dir_entries(sb, root_clu);
394 if (num_subdirs < 0)
395 return -EIO;
396 set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
397
398 inode->i_uid = sbi->options.fs_uid;
399 inode->i_gid = sbi->options.fs_gid;
400 inode_inc_iversion(inode);
401 inode->i_generation = 0;
402 inode->i_mode = exfat_make_mode(sbi, EXFAT_ATTR_SUBDIR, 0777);
403 inode->i_op = &exfat_dir_inode_operations;
404 inode->i_fop = &exfat_dir_operations;
405
406 inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >> 9;
407 ei->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
408
409 exfat_save_attr(inode, EXFAT_ATTR_SUBDIR);
410 ei->i_crtime = simple_inode_init_ts(inode);
411 exfat_truncate_inode_atime(inode);
412 return 0;
413 }
414
exfat_calibrate_blocksize(struct super_block * sb,int logical_sect)415 static int exfat_calibrate_blocksize(struct super_block *sb, int logical_sect)
416 {
417 struct exfat_sb_info *sbi = EXFAT_SB(sb);
418
419 if (!is_power_of_2(logical_sect)) {
420 exfat_err(sb, "bogus logical sector size %u", logical_sect);
421 return -EIO;
422 }
423
424 if (logical_sect < sb->s_blocksize) {
425 exfat_err(sb, "logical sector size too small for device (logical sector size = %u)",
426 logical_sect);
427 return -EIO;
428 }
429
430 if (logical_sect > sb->s_blocksize) {
431 brelse(sbi->boot_bh);
432 sbi->boot_bh = NULL;
433
434 if (!sb_set_blocksize(sb, logical_sect)) {
435 exfat_err(sb, "unable to set blocksize %u",
436 logical_sect);
437 return -EIO;
438 }
439 sbi->boot_bh = sb_bread(sb, 0);
440 if (!sbi->boot_bh) {
441 exfat_err(sb, "unable to read boot sector (logical sector size = %lu)",
442 sb->s_blocksize);
443 return -EIO;
444 }
445 }
446 return 0;
447 }
448
exfat_read_boot_sector(struct super_block * sb)449 static int exfat_read_boot_sector(struct super_block *sb)
450 {
451 struct boot_sector *p_boot;
452 struct exfat_sb_info *sbi = EXFAT_SB(sb);
453
454 /* set block size to read super block */
455 sb_min_blocksize(sb, 512);
456
457 /* read boot sector */
458 sbi->boot_bh = sb_bread(sb, 0);
459 if (!sbi->boot_bh) {
460 exfat_err(sb, "unable to read boot sector");
461 return -EIO;
462 }
463 p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
464
465 /* check the validity of BOOT */
466 if (le16_to_cpu((p_boot->signature)) != BOOT_SIGNATURE) {
467 exfat_err(sb, "invalid boot record signature");
468 return -EINVAL;
469 }
470
471 if (memcmp(p_boot->fs_name, STR_EXFAT, BOOTSEC_FS_NAME_LEN)) {
472 exfat_err(sb, "invalid fs_name"); /* fs_name may unprintable */
473 return -EINVAL;
474 }
475
476 /*
477 * must_be_zero field must be filled with zero to prevent mounting
478 * from FAT volume.
479 */
480 if (memchr_inv(p_boot->must_be_zero, 0, sizeof(p_boot->must_be_zero)))
481 return -EINVAL;
482
483 if (p_boot->num_fats != 1 && p_boot->num_fats != 2) {
484 exfat_err(sb, "bogus number of FAT structure");
485 return -EINVAL;
486 }
487
488 /*
489 * sect_size_bits could be at least 9 and at most 12.
490 */
491 if (p_boot->sect_size_bits < EXFAT_MIN_SECT_SIZE_BITS ||
492 p_boot->sect_size_bits > EXFAT_MAX_SECT_SIZE_BITS) {
493 exfat_err(sb, "bogus sector size bits : %u",
494 p_boot->sect_size_bits);
495 return -EINVAL;
496 }
497
498 /*
499 * sect_per_clus_bits could be at least 0 and at most 25 - sect_size_bits.
500 */
501 if (p_boot->sect_per_clus_bits > EXFAT_MAX_SECT_PER_CLUS_BITS(p_boot)) {
502 exfat_err(sb, "bogus sectors bits per cluster : %u",
503 p_boot->sect_per_clus_bits);
504 return -EINVAL;
505 }
506
507 sbi->sect_per_clus = 1 << p_boot->sect_per_clus_bits;
508 sbi->sect_per_clus_bits = p_boot->sect_per_clus_bits;
509 sbi->cluster_size_bits = p_boot->sect_per_clus_bits +
510 p_boot->sect_size_bits;
511 sbi->cluster_size = 1 << sbi->cluster_size_bits;
512 sbi->num_FAT_sectors = le32_to_cpu(p_boot->fat_length);
513 sbi->FAT1_start_sector = le32_to_cpu(p_boot->fat_offset);
514 sbi->FAT2_start_sector = le32_to_cpu(p_boot->fat_offset);
515 if (p_boot->num_fats == 2)
516 sbi->FAT2_start_sector += sbi->num_FAT_sectors;
517 sbi->data_start_sector = le32_to_cpu(p_boot->clu_offset);
518 sbi->num_sectors = le64_to_cpu(p_boot->vol_length);
519 /* because the cluster index starts with 2 */
520 sbi->num_clusters = le32_to_cpu(p_boot->clu_count) +
521 EXFAT_RESERVED_CLUSTERS;
522
523 sbi->root_dir = le32_to_cpu(p_boot->root_cluster);
524 sbi->dentries_per_clu = 1 <<
525 (sbi->cluster_size_bits - DENTRY_SIZE_BITS);
526
527 sbi->vol_flags = le16_to_cpu(p_boot->vol_flags);
528 sbi->vol_flags_persistent = sbi->vol_flags & (VOLUME_DIRTY | MEDIA_FAILURE);
529 sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
530 sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED;
531
532 /* check consistencies */
533 if ((u64)sbi->num_FAT_sectors << p_boot->sect_size_bits <
534 (u64)sbi->num_clusters * 4) {
535 exfat_err(sb, "bogus fat length");
536 return -EINVAL;
537 }
538
539 if (sbi->data_start_sector <
540 (u64)sbi->FAT1_start_sector +
541 (u64)sbi->num_FAT_sectors * p_boot->num_fats) {
542 exfat_err(sb, "bogus data start sector");
543 return -EINVAL;
544 }
545
546 if (sbi->vol_flags & VOLUME_DIRTY)
547 exfat_warn(sb, "Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
548 if (sbi->vol_flags & MEDIA_FAILURE)
549 exfat_warn(sb, "Medium has reported failures. Some data may be lost.");
550
551 /* exFAT file size is limited by a disk volume size */
552 sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) <<
553 sbi->cluster_size_bits;
554
555 /* check logical sector size */
556 if (exfat_calibrate_blocksize(sb, 1 << p_boot->sect_size_bits))
557 return -EIO;
558
559 return 0;
560 }
561
exfat_verify_boot_region(struct super_block * sb)562 static int exfat_verify_boot_region(struct super_block *sb)
563 {
564 struct buffer_head *bh = NULL;
565 u32 chksum = 0;
566 __le32 *p_sig, *p_chksum;
567 int sn, i;
568
569 /* read boot sector sub-regions */
570 for (sn = 0; sn < 11; sn++) {
571 bh = sb_bread(sb, sn);
572 if (!bh)
573 return -EIO;
574
575 if (sn != 0 && sn <= 8) {
576 /* extended boot sector sub-regions */
577 p_sig = (__le32 *)&bh->b_data[sb->s_blocksize - 4];
578 if (le32_to_cpu(*p_sig) != EXBOOT_SIGNATURE)
579 exfat_warn(sb, "Invalid exboot-signature(sector = %d): 0x%08x",
580 sn, le32_to_cpu(*p_sig));
581 }
582
583 chksum = exfat_calc_chksum32(bh->b_data, sb->s_blocksize,
584 chksum, sn ? CS_DEFAULT : CS_BOOT_SECTOR);
585 brelse(bh);
586 }
587
588 /* boot checksum sub-regions */
589 bh = sb_bread(sb, sn);
590 if (!bh)
591 return -EIO;
592
593 for (i = 0; i < sb->s_blocksize; i += sizeof(u32)) {
594 p_chksum = (__le32 *)&bh->b_data[i];
595 if (le32_to_cpu(*p_chksum) != chksum) {
596 exfat_err(sb, "Invalid boot checksum (boot checksum : 0x%08x, checksum : 0x%08x)",
597 le32_to_cpu(*p_chksum), chksum);
598 brelse(bh);
599 return -EINVAL;
600 }
601 }
602 brelse(bh);
603 return 0;
604 }
605
606 /* mount the file system volume */
__exfat_fill_super(struct super_block * sb,struct exfat_chain * root_clu)607 static int __exfat_fill_super(struct super_block *sb,
608 struct exfat_chain *root_clu)
609 {
610 int ret;
611 struct exfat_sb_info *sbi = EXFAT_SB(sb);
612
613 ret = exfat_read_boot_sector(sb);
614 if (ret) {
615 exfat_err(sb, "failed to read boot sector");
616 goto free_bh;
617 }
618
619 ret = exfat_verify_boot_region(sb);
620 if (ret) {
621 exfat_err(sb, "invalid boot region");
622 goto free_bh;
623 }
624
625 /*
626 * Call exfat_count_num_cluster() before searching for up-case and
627 * bitmap directory entries to avoid infinite loop if they are missing
628 * and the cluster chain includes a loop.
629 */
630 exfat_chain_set(root_clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
631 ret = exfat_count_num_clusters(sb, root_clu, &root_clu->size);
632 if (ret) {
633 exfat_err(sb, "failed to count the number of clusters in root");
634 goto free_bh;
635 }
636
637 ret = exfat_create_upcase_table(sb);
638 if (ret) {
639 exfat_err(sb, "failed to load upcase table");
640 goto free_bh;
641 }
642
643 ret = exfat_load_bitmap(sb);
644 if (ret) {
645 exfat_err(sb, "failed to load alloc-bitmap");
646 goto free_bh;
647 }
648
649 ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
650 if (ret) {
651 exfat_err(sb, "failed to scan clusters");
652 goto free_alloc_bitmap;
653 }
654
655 return 0;
656
657 free_alloc_bitmap:
658 exfat_free_bitmap(sbi);
659 free_bh:
660 brelse(sbi->boot_bh);
661 return ret;
662 }
663
exfat_fill_super(struct super_block * sb,struct fs_context * fc)664 static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
665 {
666 struct exfat_sb_info *sbi = sb->s_fs_info;
667 struct exfat_mount_options *opts = &sbi->options;
668 struct inode *root_inode;
669 struct exfat_chain root_clu;
670 int err;
671
672 if (opts->allow_utime == (unsigned short)-1)
673 opts->allow_utime = ~opts->fs_dmask & 0022;
674
675 if (opts->discard && !bdev_max_discard_sectors(sb->s_bdev)) {
676 exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
677 opts->discard = 0;
678 }
679
680 sb->s_flags |= SB_NODIRATIME;
681 sb->s_magic = EXFAT_SUPER_MAGIC;
682 sb->s_op = &exfat_sops;
683
684 sb->s_time_gran = 10 * NSEC_PER_MSEC;
685 sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
686 sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
687
688 err = __exfat_fill_super(sb, &root_clu);
689 if (err) {
690 exfat_err(sb, "failed to recognize exfat type");
691 goto check_nls_io;
692 }
693
694 /* set up enough so that it can read an inode */
695 exfat_hash_init(sb);
696
697 if (!strcmp(sbi->options.iocharset, "utf8"))
698 opts->utf8 = 1;
699 else {
700 sbi->nls_io = load_nls(sbi->options.iocharset);
701 if (!sbi->nls_io) {
702 exfat_err(sb, "IO charset %s not found",
703 sbi->options.iocharset);
704 err = -EINVAL;
705 goto free_table;
706 }
707 }
708
709 if (sbi->options.utf8)
710 sb->s_d_op = &exfat_utf8_dentry_ops;
711 else
712 sb->s_d_op = &exfat_dentry_ops;
713
714 root_inode = new_inode(sb);
715 if (!root_inode) {
716 exfat_err(sb, "failed to allocate root inode");
717 err = -ENOMEM;
718 goto free_table;
719 }
720
721 root_inode->i_ino = EXFAT_ROOT_INO;
722 inode_set_iversion(root_inode, 1);
723 err = exfat_read_root(root_inode, &root_clu);
724 if (err) {
725 exfat_err(sb, "failed to initialize root inode");
726 goto put_inode;
727 }
728
729 exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
730 insert_inode_hash(root_inode);
731
732 sb->s_root = d_make_root(root_inode);
733 if (!sb->s_root) {
734 exfat_err(sb, "failed to get the root dentry");
735 err = -ENOMEM;
736 goto free_table;
737 }
738
739 return 0;
740
741 put_inode:
742 iput(root_inode);
743 sb->s_root = NULL;
744
745 free_table:
746 exfat_free_bitmap(sbi);
747 brelse(sbi->boot_bh);
748
749 check_nls_io:
750 return err;
751 }
752
exfat_get_tree(struct fs_context * fc)753 static int exfat_get_tree(struct fs_context *fc)
754 {
755 return get_tree_bdev(fc, exfat_fill_super);
756 }
757
exfat_free_sbi(struct exfat_sb_info * sbi)758 static void exfat_free_sbi(struct exfat_sb_info *sbi)
759 {
760 exfat_free_iocharset(sbi);
761 kfree(sbi);
762 }
763
exfat_free(struct fs_context * fc)764 static void exfat_free(struct fs_context *fc)
765 {
766 struct exfat_sb_info *sbi = fc->s_fs_info;
767
768 if (sbi)
769 exfat_free_sbi(sbi);
770 }
771
exfat_reconfigure(struct fs_context * fc)772 static int exfat_reconfigure(struct fs_context *fc)
773 {
774 fc->sb_flags |= SB_NODIRATIME;
775
776 /* volume flag will be updated in exfat_sync_fs */
777 sync_filesystem(fc->root->d_sb);
778 return 0;
779 }
780
781 static const struct fs_context_operations exfat_context_ops = {
782 .parse_param = exfat_parse_param,
783 .get_tree = exfat_get_tree,
784 .free = exfat_free,
785 .reconfigure = exfat_reconfigure,
786 };
787
exfat_init_fs_context(struct fs_context * fc)788 static int exfat_init_fs_context(struct fs_context *fc)
789 {
790 struct exfat_sb_info *sbi;
791
792 sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
793 if (!sbi)
794 return -ENOMEM;
795
796 mutex_init(&sbi->s_lock);
797 mutex_init(&sbi->bitmap_lock);
798 ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
799 DEFAULT_RATELIMIT_BURST);
800
801 sbi->options.fs_uid = current_uid();
802 sbi->options.fs_gid = current_gid();
803 sbi->options.fs_fmask = current->fs->umask;
804 sbi->options.fs_dmask = current->fs->umask;
805 sbi->options.allow_utime = -1;
806 sbi->options.iocharset = exfat_default_iocharset;
807 sbi->options.errors = EXFAT_ERRORS_RO;
808
809 fc->s_fs_info = sbi;
810 fc->ops = &exfat_context_ops;
811 return 0;
812 }
813
delayed_free(struct rcu_head * p)814 static void delayed_free(struct rcu_head *p)
815 {
816 struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu);
817
818 unload_nls(sbi->nls_io);
819 exfat_free_upcase_table(sbi);
820 exfat_free_sbi(sbi);
821 }
822
exfat_kill_sb(struct super_block * sb)823 static void exfat_kill_sb(struct super_block *sb)
824 {
825 struct exfat_sb_info *sbi = sb->s_fs_info;
826
827 kill_block_super(sb);
828 if (sbi)
829 call_rcu(&sbi->rcu, delayed_free);
830 }
831
832 static struct file_system_type exfat_fs_type = {
833 .owner = THIS_MODULE,
834 .name = "exfat",
835 .init_fs_context = exfat_init_fs_context,
836 .parameters = exfat_parameters,
837 .kill_sb = exfat_kill_sb,
838 .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
839 };
840
exfat_inode_init_once(void * foo)841 static void exfat_inode_init_once(void *foo)
842 {
843 struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
844
845 spin_lock_init(&ei->cache_lru_lock);
846 ei->nr_caches = 0;
847 ei->cache_valid_id = EXFAT_CACHE_VALID + 1;
848 INIT_LIST_HEAD(&ei->cache_lru);
849 INIT_HLIST_NODE(&ei->i_hash_fat);
850 inode_init_once(&ei->vfs_inode);
851 }
852
init_exfat_fs(void)853 static int __init init_exfat_fs(void)
854 {
855 int err;
856
857 err = exfat_cache_init();
858 if (err)
859 return err;
860
861 exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
862 sizeof(struct exfat_inode_info),
863 0, SLAB_RECLAIM_ACCOUNT,
864 exfat_inode_init_once);
865 if (!exfat_inode_cachep) {
866 err = -ENOMEM;
867 goto shutdown_cache;
868 }
869
870 err = register_filesystem(&exfat_fs_type);
871 if (err)
872 goto destroy_cache;
873
874 return 0;
875
876 destroy_cache:
877 kmem_cache_destroy(exfat_inode_cachep);
878 shutdown_cache:
879 exfat_cache_shutdown();
880 return err;
881 }
882
exit_exfat_fs(void)883 static void __exit exit_exfat_fs(void)
884 {
885 /*
886 * Make sure all delayed rcu free inodes are flushed before we
887 * destroy cache.
888 */
889 rcu_barrier();
890 kmem_cache_destroy(exfat_inode_cachep);
891 unregister_filesystem(&exfat_fs_type);
892 exfat_cache_shutdown();
893 }
894
895 module_init(init_exfat_fs);
896 module_exit(exit_exfat_fs);
897
898 MODULE_ALIAS_FS("exfat");
899 MODULE_LICENSE("GPL");
900 MODULE_DESCRIPTION("exFAT filesystem support");
901 MODULE_AUTHOR("Samsung Electronics Co., Ltd.");
902