fs/exfat/super.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
   4  */
   5
   6 #include <linux/fs_context.h>
   7 #include <linux/fs_parser.h>
   8 #include <linux/module.h>
   9 #include <linux/init.h>
  10 #include <linux/time.h>
  11 #include <linux/mount.h>
  12 #include <linux/cred.h>
  13 #include <linux/statfs.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/blkdev.h>
  16 #include <linux/fs_struct.h>
  17 #include <linux/iversion.h>
  18 #include <linux/nls.h>
  19 #include <linux/buffer_head.h>
  20
  21 #include "exfat_raw.h"
  22 #include "exfat_fs.h"
  23
  24 static char exfat_default_iocharset[] = CONFIG_EXFAT_DEFAULT_IOCHARSET;
  25 static struct kmem_cache *exfat_inode_cachep;
  26
  27 static void exfat_free_iocharset(struct exfat_sb_info *sbi)
  28 {
  29         if (sbi->options.iocharset != exfat_default_iocharset)
  30                 kfree(sbi->options.iocharset);
  31 }
  32
  33 static void exfat_delayed_free(struct rcu_head *p)
  34 {
  35         struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu);
  36
  37         unload_nls(sbi->nls_io);
  38         exfat_free_iocharset(sbi);
  39         exfat_free_upcase_table(sbi);
  40         kfree(sbi);
  41 }
  42
  43 static void exfat_put_super(struct super_block *sb)
  44 {
  45         struct exfat_sb_info *sbi = EXFAT_SB(sb);
  46
  47         mutex_lock(&sbi->s_lock);
  48         if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state))
  49                 sync_blockdev(sb->s_bdev);
  50         exfat_set_vol_flags(sb, VOL_CLEAN);
  51         exfat_free_bitmap(sbi);
  52         brelse(sbi->pbr_bh);
  53         mutex_unlock(&sbi->s_lock);
  54
  55         call_rcu(&sbi->rcu, exfat_delayed_free);
  56 }
  57
  58 static int exfat_sync_fs(struct super_block *sb, int wait)
  59 {
  60         struct exfat_sb_info *sbi = EXFAT_SB(sb);
  61         int err = 0;
  62
  63         /* If there are some dirty buffers in the bdev inode */
  64         mutex_lock(&sbi->s_lock);
  65         if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state)) {
  66                 sync_blockdev(sb->s_bdev);
  67                 if (exfat_set_vol_flags(sb, VOL_CLEAN))
  68                         err = -EIO;
  69         }
  70         mutex_unlock(&sbi->s_lock);
  71         return err;
  72 }
  73
  74 static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
  75 {
  76         struct super_block *sb = dentry->d_sb;
  77         struct exfat_sb_info *sbi = EXFAT_SB(sb);
  78         unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
  79
  80         if (sbi->used_clusters == EXFAT_CLUSTERS_UNTRACKED) {
  81                 mutex_lock(&sbi->s_lock);
  82                 if (exfat_count_used_clusters(sb, &sbi->used_clusters)) {
  83                         mutex_unlock(&sbi->s_lock);
  84                         return -EIO;
  85                 }
  86                 mutex_unlock(&sbi->s_lock);
  87         }
  88
  89         buf->f_type = sb->s_magic;
  90         buf->f_bsize = sbi->cluster_size;
  91         buf->f_blocks = sbi->num_clusters - 2; /* clu 0 & 1 */
  92         buf->f_bfree = buf->f_blocks - sbi->used_clusters;
  93         buf->f_bavail = buf->f_bfree;
  94         buf->f_fsid.val[0] = (unsigned int)id;
  95         buf->f_fsid.val[1] = (unsigned int)(id >> 32);
  96         /* Unicode utf16 255 characters */
  97         buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE;
  98         return 0;
  99 }
 100
 101 int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)
 102 {
 103         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 104         struct pbr64 *bpb = (struct pbr64 *)sbi->pbr_bh->b_data;
 105         bool sync = 0;
 106
 107         /* flags are not changed */
 108         if (sbi->vol_flag == new_flag)
 109                 return 0;
 110
 111         sbi->vol_flag = new_flag;
 112
 113         /* skip updating volume dirty flag,
 114          * if this volume has been mounted with read-only
 115          */
 116         if (sb_rdonly(sb))
 117                 return 0;
 118
 119         bpb->bsx.vol_flags = cpu_to_le16(new_flag);
 120
 121         if (new_flag == VOL_DIRTY && !buffer_dirty(sbi->pbr_bh))
 122                 sync = true;
 123         else
 124                 sync = false;
 125
 126         set_buffer_uptodate(sbi->pbr_bh);
 127         mark_buffer_dirty(sbi->pbr_bh);
 128
 129         if (sync)
 130                 sync_dirty_buffer(sbi->pbr_bh);
 131         return 0;
 132 }
 133
 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->time_offset)
 163                 seq_printf(m, ",time_offset=%d", opts->time_offset);
 164         return 0;
 165 }
 166
 167 static struct inode *exfat_alloc_inode(struct super_block *sb)
 168 {
 169         struct exfat_inode_info *ei;
 170
 171         ei = kmem_cache_alloc(exfat_inode_cachep, GFP_NOFS);
 172         if (!ei)
 173                 return NULL;
 174
 175         init_rwsem(&ei->truncate_lock);
 176         return &ei->vfs_inode;
 177 }
 178
 179 static void exfat_free_inode(struct inode *inode)
 180 {
 181         kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
 182 }
 183
 184 static const struct super_operations exfat_sops = {
 185         .alloc_inode    = exfat_alloc_inode,
 186         .free_inode     = exfat_free_inode,
 187         .write_inode    = exfat_write_inode,
 188         .evict_inode    = exfat_evict_inode,
 189         .put_super      = exfat_put_super,
 190         .sync_fs        = exfat_sync_fs,
 191         .statfs         = exfat_statfs,
 192         .show_options   = exfat_show_options,
 193 };
 194
 195 enum {
 196         Opt_uid,
 197         Opt_gid,
 198         Opt_umask,
 199         Opt_dmask,
 200         Opt_fmask,
 201         Opt_allow_utime,
 202         Opt_charset,
 203         Opt_errors,
 204         Opt_discard,
 205         Opt_time_offset,
 206
 207         /* Deprecated options */
 208         Opt_utf8,
 209         Opt_debug,
 210         Opt_namecase,
 211         Opt_codepage,
 212 };
 213
 214 static const struct constant_table exfat_param_enums[] = {
 215         { "continue",           EXFAT_ERRORS_CONT },
 216         { "panic",              EXFAT_ERRORS_PANIC },
 217         { "remount-ro",         EXFAT_ERRORS_RO },
 218         {}
 219 };
 220
 221 static const struct fs_parameter_spec exfat_parameters[] = {
 222         fsparam_u32("uid",                      Opt_uid),
 223         fsparam_u32("gid",                      Opt_gid),
 224         fsparam_u32oct("umask",                 Opt_umask),
 225         fsparam_u32oct("dmask",                 Opt_dmask),
 226         fsparam_u32oct("fmask",                 Opt_fmask),
 227         fsparam_u32oct("allow_utime",           Opt_allow_utime),
 228         fsparam_string("iocharset",             Opt_charset),
 229         fsparam_enum("errors",                  Opt_errors, exfat_param_enums),
 230         fsparam_flag("discard",                 Opt_discard),
 231         fsparam_s32("time_offset",              Opt_time_offset),
 232         __fsparam(NULL, "utf8",                 Opt_utf8, fs_param_deprecated,
 233                   NULL),
 234         __fsparam(NULL, "debug",                Opt_debug, fs_param_deprecated,
 235                   NULL),
 236         __fsparam(fs_param_is_u32, "namecase",  Opt_namecase,
 237                   fs_param_deprecated, NULL),
 238         __fsparam(fs_param_is_u32, "codepage",  Opt_codepage,
 239                   fs_param_deprecated, NULL),
 240         {}
 241 };
 242
 243 static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
 244 {
 245         struct exfat_sb_info *sbi = fc->s_fs_info;
 246         struct exfat_mount_options *opts = &sbi->options;
 247         struct fs_parse_result result;
 248         int opt;
 249
 250         opt = fs_parse(fc, exfat_parameters, param, &result);
 251         if (opt < 0)
 252                 return opt;
 253
 254         switch (opt) {
 255         case Opt_uid:
 256                 opts->fs_uid = make_kuid(current_user_ns(), result.uint_32);
 257                 break;
 258         case Opt_gid:
 259                 opts->fs_gid = make_kgid(current_user_ns(), result.uint_32);
 260                 break;
 261         case Opt_umask:
 262                 opts->fs_fmask = result.uint_32;
 263                 opts->fs_dmask = result.uint_32;
 264                 break;
 265         case Opt_dmask:
 266                 opts->fs_dmask = result.uint_32;
 267                 break;
 268         case Opt_fmask:
 269                 opts->fs_fmask = result.uint_32;
 270                 break;
 271         case Opt_allow_utime:
 272                 opts->allow_utime = result.uint_32 & 0022;
 273                 break;
 274         case Opt_charset:
 275                 exfat_free_iocharset(sbi);
 276                 opts->iocharset = kstrdup(param->string, GFP_KERNEL);
 277                 if (!opts->iocharset)
 278                         return -ENOMEM;
 279                 break;
 280         case Opt_errors:
 281                 opts->errors = result.uint_32;
 282                 break;
 283         case Opt_discard:
 284                 opts->discard = 1;
 285                 break;
 286         case Opt_time_offset:
 287                 /*
 288                  * Make the limit 24 just in case someone invents something
 289                  * unusual.
 290                  */
 291                 if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
 292                         return -EINVAL;
 293                 opts->time_offset = result.int_32;
 294                 break;
 295         case Opt_utf8:
 296         case Opt_debug:
 297         case Opt_namecase:
 298         case Opt_codepage:
 299                 break;
 300         default:
 301                 return -EINVAL;
 302         }
 303
 304         return 0;
 305 }
 306
 307 static void exfat_hash_init(struct super_block *sb)
 308 {
 309         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 310         int i;
 311
 312         spin_lock_init(&sbi->inode_hash_lock);
 313         for (i = 0; i < EXFAT_HASH_SIZE; i++)
 314                 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
 315 }
 316
 317 static int exfat_read_root(struct inode *inode)
 318 {
 319         struct super_block *sb = inode->i_sb;
 320         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 321         struct exfat_inode_info *ei = EXFAT_I(inode);
 322         struct exfat_chain cdir;
 323         int num_subdirs, num_clu = 0;
 324
 325         exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
 326         ei->entry = -1;
 327         ei->start_clu = sbi->root_dir;
 328         ei->flags = ALLOC_FAT_CHAIN;
 329         ei->type = TYPE_DIR;
 330         ei->version = 0;
 331         ei->rwoffset = 0;
 332         ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
 333         ei->hint_stat.eidx = 0;
 334         ei->hint_stat.clu = sbi->root_dir;
 335         ei->hint_femp.eidx = EXFAT_HINT_NONE;
 336
 337         exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
 338         if (exfat_count_num_clusters(sb, &cdir, &num_clu))
 339                 return -EIO;
 340         i_size_write(inode, num_clu << sbi->cluster_size_bits);
 341
 342         num_subdirs = exfat_count_dir_entries(sb, &cdir);
 343         if (num_subdirs < 0)
 344                 return -EIO;
 345         set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
 346
 347         inode->i_uid = sbi->options.fs_uid;
 348         inode->i_gid = sbi->options.fs_gid;
 349         inode_inc_iversion(inode);
 350         inode->i_generation = 0;
 351         inode->i_mode = exfat_make_mode(sbi, ATTR_SUBDIR, 0777);
 352         inode->i_op = &exfat_dir_inode_operations;
 353         inode->i_fop = &exfat_dir_operations;
 354
 355         inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1))
 356                         & ~(sbi->cluster_size - 1)) >> inode->i_blkbits;
 357         EXFAT_I(inode)->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
 358         EXFAT_I(inode)->i_size_aligned = i_size_read(inode);
 359         EXFAT_I(inode)->i_size_ondisk = i_size_read(inode);
 360
 361         exfat_save_attr(inode, ATTR_SUBDIR);
 362         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
 363                 current_time(inode);
 364         exfat_truncate_atime(&inode->i_atime);
 365         exfat_cache_init_inode(inode);
 366         return 0;
 367 }
 368
 369 static struct pbr *exfat_read_pbr_with_logical_sector(struct super_block *sb)
 370 {
 371         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 372         struct pbr *p_pbr = (struct pbr *) (sbi->pbr_bh)->b_data;
 373         unsigned short logical_sect = 0;
 374
 375         logical_sect = 1 << p_pbr->bsx.f64.sect_size_bits;
 376
 377         if (!is_power_of_2(logical_sect) ||
 378             logical_sect < 512 || logical_sect > 4096) {
 379                 exfat_msg(sb, KERN_ERR, "bogus logical sector size %u",
 380                                 logical_sect);
 381                 return NULL;
 382         }
 383
 384         if (logical_sect < sb->s_blocksize) {
 385                 exfat_msg(sb, KERN_ERR,
 386                         "logical sector size too small for device (logical sector size = %u)",
 387                         logical_sect);
 388                 return NULL;
 389         }
 390
 391         if (logical_sect > sb->s_blocksize) {
 392                 brelse(sbi->pbr_bh);
 393                 sbi->pbr_bh = NULL;
 394
 395                 if (!sb_set_blocksize(sb, logical_sect)) {
 396                         exfat_msg(sb, KERN_ERR,
 397                                 "unable to set blocksize %u", logical_sect);
 398                         return NULL;
 399                 }
 400                 sbi->pbr_bh = sb_bread(sb, 0);
 401                 if (!sbi->pbr_bh) {
 402                         exfat_msg(sb, KERN_ERR,
 403                                 "unable to read boot sector (logical sector size = %lu)",
 404                                 sb->s_blocksize);
 405                         return NULL;
 406                 }
 407
 408                 p_pbr = (struct pbr *)sbi->pbr_bh->b_data;
 409         }
 410         return p_pbr;
 411 }
 412
 413 /* mount the file system volume */
 414 static int __exfat_fill_super(struct super_block *sb)
 415 {
 416         int ret;
 417         struct pbr *p_pbr;
 418         struct pbr64 *p_bpb;
 419         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 420
 421         /* set block size to read super block */
 422         sb_min_blocksize(sb, 512);
 423
 424         /* read boot sector */
 425         sbi->pbr_bh = sb_bread(sb, 0);
 426         if (!sbi->pbr_bh) {
 427                 exfat_msg(sb, KERN_ERR, "unable to read boot sector");
 428                 return -EIO;
 429         }
 430
 431         /* PRB is read */
 432         p_pbr = (struct pbr *)sbi->pbr_bh->b_data;
 433
 434         /* check the validity of PBR */
 435         if (le16_to_cpu((p_pbr->signature)) != PBR_SIGNATURE) {
 436                 exfat_msg(sb, KERN_ERR, "invalid boot record signature");
 437                 ret = -EINVAL;
 438                 goto free_bh;
 439         }
 440
 441
 442         /* check logical sector size */
 443         p_pbr = exfat_read_pbr_with_logical_sector(sb);
 444         if (!p_pbr) {
 445                 ret = -EIO;
 446                 goto free_bh;
 447         }
 448
 449         /*
 450          * res_zero field must be filled with zero to prevent mounting
 451          * from FAT volume.
 452          */
 453         if (memchr_inv(p_pbr->bpb.f64.res_zero, 0,
 454                         sizeof(p_pbr->bpb.f64.res_zero))) {
 455                 ret = -EINVAL;
 456                 goto free_bh;
 457         }
 458
 459         p_bpb = (struct pbr64 *)p_pbr;
 460         if (!p_bpb->bsx.num_fats) {
 461                 exfat_msg(sb, KERN_ERR, "bogus number of FAT structure");
 462                 ret = -EINVAL;
 463                 goto free_bh;
 464         }
 465
 466         sbi->sect_per_clus = 1 << p_bpb->bsx.sect_per_clus_bits;
 467         sbi->sect_per_clus_bits = p_bpb->bsx.sect_per_clus_bits;
 468         sbi->cluster_size_bits = sbi->sect_per_clus_bits + sb->s_blocksize_bits;
 469         sbi->cluster_size = 1 << sbi->cluster_size_bits;
 470         sbi->num_FAT_sectors = le32_to_cpu(p_bpb->bsx.fat_length);
 471         sbi->FAT1_start_sector = le32_to_cpu(p_bpb->bsx.fat_offset);
 472         sbi->FAT2_start_sector = p_bpb->bsx.num_fats == 1 ?
 473                 sbi->FAT1_start_sector :
 474                         sbi->FAT1_start_sector + sbi->num_FAT_sectors;
 475         sbi->data_start_sector = le32_to_cpu(p_bpb->bsx.clu_offset);
 476         sbi->num_sectors = le64_to_cpu(p_bpb->bsx.vol_length);
 477         /* because the cluster index starts with 2 */
 478         sbi->num_clusters = le32_to_cpu(p_bpb->bsx.clu_count) +
 479                 EXFAT_RESERVED_CLUSTERS;
 480
 481         sbi->root_dir = le32_to_cpu(p_bpb->bsx.root_cluster);
 482         sbi->dentries_per_clu = 1 <<
 483                 (sbi->cluster_size_bits - DENTRY_SIZE_BITS);
 484
 485         sbi->vol_flag = le16_to_cpu(p_bpb->bsx.vol_flags);
 486         sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
 487         sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED;
 488
 489         if (le16_to_cpu(p_bpb->bsx.vol_flags) & VOL_DIRTY) {
 490                 sbi->vol_flag |= VOL_DIRTY;
 491                 exfat_msg(sb, KERN_WARNING,
 492                         "Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
 493         }
 494
 495         /* exFAT file size is limited by a disk volume size */
 496         sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) <<
 497                 sbi->cluster_size_bits;
 498
 499         ret = exfat_create_upcase_table(sb);
 500         if (ret) {
 501                 exfat_msg(sb, KERN_ERR, "failed to load upcase table");
 502                 goto free_bh;
 503         }
 504
 505         ret = exfat_load_bitmap(sb);
 506         if (ret) {
 507                 exfat_msg(sb, KERN_ERR, "failed to load alloc-bitmap");
 508                 goto free_upcase_table;
 509         }
 510
 511         ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
 512         if (ret) {
 513                 exfat_msg(sb, KERN_ERR, "failed to scan clusters");
 514                 goto free_alloc_bitmap;
 515         }
 516
 517         return 0;
 518
 519 free_alloc_bitmap:
 520         exfat_free_bitmap(sbi);
 521 free_upcase_table:
 522         exfat_free_upcase_table(sbi);
 523 free_bh:
 524         brelse(sbi->pbr_bh);
 525         return ret;
 526 }
 527
 528 static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 529 {
 530         struct exfat_sb_info *sbi = sb->s_fs_info;
 531         struct exfat_mount_options *opts = &sbi->options;
 532         struct inode *root_inode;
 533         int err;
 534
 535         if (opts->allow_utime == (unsigned short)-1)
 536                 opts->allow_utime = ~opts->fs_dmask & 0022;
 537
 538         if (opts->discard) {
 539                 struct request_queue *q = bdev_get_queue(sb->s_bdev);
 540
 541                 if (!blk_queue_discard(q)) {
 542                         exfat_msg(sb, KERN_WARNING,
 543                                 "mounting with \"discard\" option, but the device does not support discard");
 544                         opts->discard = 0;
 545                 }
 546         }
 547
 548         sb->s_flags |= SB_NODIRATIME;
 549         sb->s_magic = EXFAT_SUPER_MAGIC;
 550         sb->s_op = &exfat_sops;
 551
 552         sb->s_time_gran = 10 * NSEC_PER_MSEC;
 553         sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
 554         sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
 555
 556         err = __exfat_fill_super(sb);
 557         if (err) {
 558                 exfat_msg(sb, KERN_ERR, "failed to recognize exfat type");
 559                 goto check_nls_io;
 560         }
 561
 562         /* set up enough so that it can read an inode */
 563         exfat_hash_init(sb);
 564
 565         if (!strcmp(sbi->options.iocharset, "utf8"))
 566                 opts->utf8 = 1;
 567         else {
 568                 sbi->nls_io = load_nls(sbi->options.iocharset);
 569                 if (!sbi->nls_io) {
 570                         exfat_msg(sb, KERN_ERR, "IO charset %s not found",
 571                                         sbi->options.iocharset);
 572                         err = -EINVAL;
 573                         goto free_table;
 574                 }
 575         }
 576
 577         if (sbi->options.utf8)
 578                 sb->s_d_op = &exfat_utf8_dentry_ops;
 579         else
 580                 sb->s_d_op = &exfat_dentry_ops;
 581
 582         root_inode = new_inode(sb);
 583         if (!root_inode) {
 584                 exfat_msg(sb, KERN_ERR, "failed to allocate root inode.");
 585                 err = -ENOMEM;
 586                 goto free_table;
 587         }
 588
 589         root_inode->i_ino = EXFAT_ROOT_INO;
 590         inode_set_iversion(root_inode, 1);
 591         err = exfat_read_root(root_inode);
 592         if (err) {
 593                 exfat_msg(sb, KERN_ERR, "failed to initialize root inode.");
 594                 goto put_inode;
 595         }
 596
 597         exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
 598         insert_inode_hash(root_inode);
 599
 600         sb->s_root = d_make_root(root_inode);
 601         if (!sb->s_root) {
 602                 exfat_msg(sb, KERN_ERR, "failed to get the root dentry");
 603                 err = -ENOMEM;
 604                 goto put_inode;
 605         }
 606
 607         return 0;
 608
 609 put_inode:
 610         iput(root_inode);
 611         sb->s_root = NULL;
 612
 613 free_table:
 614         exfat_free_upcase_table(sbi);
 615         exfat_free_bitmap(sbi);
 616         brelse(sbi->pbr_bh);
 617
 618 check_nls_io:
 619         unload_nls(sbi->nls_io);
 620         exfat_free_iocharset(sbi);
 621         sb->s_fs_info = NULL;
 622         kfree(sbi);
 623         return err;
 624 }
 625
 626 static int exfat_get_tree(struct fs_context *fc)
 627 {
 628         return get_tree_bdev(fc, exfat_fill_super);
 629 }
 630
 631 static void exfat_free(struct fs_context *fc)
 632 {
 633         kfree(fc->s_fs_info);
 634 }
 635
 636 static const struct fs_context_operations exfat_context_ops = {
 637         .parse_param    = exfat_parse_param,
 638         .get_tree       = exfat_get_tree,
 639         .free           = exfat_free,
 640 };
 641
 642 static int exfat_init_fs_context(struct fs_context *fc)
 643 {
 644         struct exfat_sb_info *sbi;
 645
 646         sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
 647         if (!sbi)
 648                 return -ENOMEM;
 649
 650         mutex_init(&sbi->s_lock);
 651         ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
 652                         DEFAULT_RATELIMIT_BURST);
 653
 654         sbi->options.fs_uid = current_uid();
 655         sbi->options.fs_gid = current_gid();
 656         sbi->options.fs_fmask = current->fs->umask;
 657         sbi->options.fs_dmask = current->fs->umask;
 658         sbi->options.allow_utime = -1;
 659         sbi->options.iocharset = exfat_default_iocharset;
 660         sbi->options.errors = EXFAT_ERRORS_RO;
 661
 662         fc->s_fs_info = sbi;
 663         fc->ops = &exfat_context_ops;
 664         return 0;
 665 }
 666
 667 static struct file_system_type exfat_fs_type = {
 668         .owner                  = THIS_MODULE,
 669         .name                   = "exfat",
 670         .init_fs_context        = exfat_init_fs_context,
 671         .parameters             = exfat_parameters,
 672         .kill_sb                = kill_block_super,
 673         .fs_flags               = FS_REQUIRES_DEV,
 674 };
 675
 676 static void exfat_inode_init_once(void *foo)
 677 {
 678         struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
 679
 680         INIT_HLIST_NODE(&ei->i_hash_fat);
 681         inode_init_once(&ei->vfs_inode);
 682 }
 683
 684 static int __init init_exfat_fs(void)
 685 {
 686         int err;
 687
 688         err = exfat_cache_init();
 689         if (err)
 690                 return err;
 691
 692         exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
 693                         sizeof(struct exfat_inode_info),
 694                         0, SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
 695                         exfat_inode_init_once);
 696         if (!exfat_inode_cachep) {
 697                 err = -ENOMEM;
 698                 goto shutdown_cache;
 699         }
 700
 701         err = register_filesystem(&exfat_fs_type);
 702         if (err)
 703                 goto destroy_cache;
 704
 705         return 0;
 706
 707 destroy_cache:
 708         kmem_cache_destroy(exfat_inode_cachep);
 709 shutdown_cache:
 710         exfat_cache_shutdown();
 711         return err;
 712 }
 713
 714 static void __exit exit_exfat_fs(void)
 715 {
 716         /*
 717          * Make sure all delayed rcu free inodes are flushed before we
 718          * destroy cache.
 719          */
 720         rcu_barrier();
 721         kmem_cache_destroy(exfat_inode_cachep);
 722         unregister_filesystem(&exfat_fs_type);
 723         exfat_cache_shutdown();
 724 }
 725
 726 module_init(init_exfat_fs);
 727 module_exit(exit_exfat_fs);
 728
 729 MODULE_ALIAS_FS("exfat");
 730 MODULE_LICENSE("GPL");
 731 MODULE_DESCRIPTION("exFAT filesystem support");
 732 MODULE_AUTHOR("Samsung Electronics Co., Ltd.");