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         mutex_unlock(&sbi->s_lock);
  53
  54         call_rcu(&sbi->rcu, exfat_delayed_free);
  55 }
  56
  57 static int exfat_sync_fs(struct super_block *sb, int wait)
  58 {
  59         struct exfat_sb_info *sbi = EXFAT_SB(sb);
  60         int err = 0;
  61
  62         /* If there are some dirty buffers in the bdev inode */
  63         mutex_lock(&sbi->s_lock);
  64         if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state)) {
  65                 sync_blockdev(sb->s_bdev);
  66                 if (exfat_set_vol_flags(sb, VOL_CLEAN))
  67                         err = -EIO;
  68         }
  69         mutex_unlock(&sbi->s_lock);
  70         return err;
  71 }
  72
  73 static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
  74 {
  75         struct super_block *sb = dentry->d_sb;
  76         struct exfat_sb_info *sbi = EXFAT_SB(sb);
  77         unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
  78
  79         if (sbi->used_clusters == EXFAT_CLUSTERS_UNTRACKED) {
  80                 mutex_lock(&sbi->s_lock);
  81                 if (exfat_count_used_clusters(sb, &sbi->used_clusters)) {
  82                         mutex_unlock(&sbi->s_lock);
  83                         return -EIO;
  84                 }
  85                 mutex_unlock(&sbi->s_lock);
  86         }
  87
  88         buf->f_type = sb->s_magic;
  89         buf->f_bsize = sbi->cluster_size;
  90         buf->f_blocks = sbi->num_clusters - 2; /* clu 0 & 1 */
  91         buf->f_bfree = buf->f_blocks - sbi->used_clusters;
  92         buf->f_bavail = buf->f_bfree;
  93         buf->f_fsid.val[0] = (unsigned int)id;
  94         buf->f_fsid.val[1] = (unsigned int)(id >> 32);
  95         /* Unicode utf16 255 characters */
  96         buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE;
  97         return 0;
  98 }
  99
 100 int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)
 101 {
 102         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 103         struct pbr64 *bpb;
 104         bool sync = 0;
 105
 106         /* flags are not changed */
 107         if (sbi->vol_flag == new_flag)
 108                 return 0;
 109
 110         sbi->vol_flag = new_flag;
 111
 112         /* skip updating volume dirty flag,
 113          * if this volume has been mounted with read-only
 114          */
 115         if (sb_rdonly(sb))
 116                 return 0;
 117
 118         if (!sbi->pbr_bh) {
 119                 sbi->pbr_bh = sb_bread(sb, 0);
 120                 if (!sbi->pbr_bh) {
 121                         exfat_msg(sb, KERN_ERR, "failed to read boot sector");
 122                         return -ENOMEM;
 123                 }
 124         }
 125
 126         bpb = (struct pbr64 *)sbi->pbr_bh->b_data;
 127         bpb->bsx.vol_flags = cpu_to_le16(new_flag);
 128
 129         if (new_flag == VOL_DIRTY && !buffer_dirty(sbi->pbr_bh))
 130                 sync = true;
 131         else
 132                 sync = false;
 133
 134         set_buffer_uptodate(sbi->pbr_bh);
 135         mark_buffer_dirty(sbi->pbr_bh);
 136
 137         if (sync)
 138                 sync_dirty_buffer(sbi->pbr_bh);
 139         return 0;
 140 }
 141
 142 static int exfat_show_options(struct seq_file *m, struct dentry *root)
 143 {
 144         struct super_block *sb = root->d_sb;
 145         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 146         struct exfat_mount_options *opts = &sbi->options;
 147
 148         /* Show partition info */
 149         if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
 150                 seq_printf(m, ",uid=%u",
 151                                 from_kuid_munged(&init_user_ns, opts->fs_uid));
 152         if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
 153                 seq_printf(m, ",gid=%u",
 154                                 from_kgid_munged(&init_user_ns, opts->fs_gid));
 155         seq_printf(m, ",fmask=%04o,dmask=%04o", opts->fs_fmask, opts->fs_dmask);
 156         if (opts->allow_utime)
 157                 seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
 158         if (opts->utf8)
 159                 seq_puts(m, ",iocharset=utf8");
 160         else if (sbi->nls_io)
 161                 seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
 162         seq_printf(m, ",bps=%ld", sb->s_blocksize);
 163         if (opts->errors == EXFAT_ERRORS_CONT)
 164                 seq_puts(m, ",errors=continue");
 165         else if (opts->errors == EXFAT_ERRORS_PANIC)
 166                 seq_puts(m, ",errors=panic");
 167         else
 168                 seq_puts(m, ",errors=remount-ro");
 169         if (opts->discard)
 170                 seq_puts(m, ",discard");
 171         if (opts->time_offset)
 172                 seq_printf(m, ",time_offset=%d", opts->time_offset);
 173         return 0;
 174 }
 175
 176 static struct inode *exfat_alloc_inode(struct super_block *sb)
 177 {
 178         struct exfat_inode_info *ei;
 179
 180         ei = kmem_cache_alloc(exfat_inode_cachep, GFP_NOFS);
 181         if (!ei)
 182                 return NULL;
 183
 184         init_rwsem(&ei->truncate_lock);
 185         return &ei->vfs_inode;
 186 }
 187
 188 static void exfat_free_inode(struct inode *inode)
 189 {
 190         kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
 191 }
 192
 193 static const struct super_operations exfat_sops = {
 194         .alloc_inode    = exfat_alloc_inode,
 195         .free_inode     = exfat_free_inode,
 196         .write_inode    = exfat_write_inode,
 197         .evict_inode    = exfat_evict_inode,
 198         .put_super      = exfat_put_super,
 199         .sync_fs        = exfat_sync_fs,
 200         .statfs         = exfat_statfs,
 201         .show_options   = exfat_show_options,
 202 };
 203
 204 enum {
 205         Opt_uid,
 206         Opt_gid,
 207         Opt_umask,
 208         Opt_dmask,
 209         Opt_fmask,
 210         Opt_allow_utime,
 211         Opt_charset,
 212         Opt_errors,
 213         Opt_discard,
 214         Opt_time_offset,
 215 };
 216
 217 static const struct constant_table exfat_param_enums[] = {
 218         { "continue",           EXFAT_ERRORS_CONT },
 219         { "panic",              EXFAT_ERRORS_PANIC },
 220         { "remount-ro",         EXFAT_ERRORS_RO },
 221         {}
 222 };
 223
 224 static const struct fs_parameter_spec exfat_parameters[] = {
 225         fsparam_u32("uid",                      Opt_uid),
 226         fsparam_u32("gid",                      Opt_gid),
 227         fsparam_u32oct("umask",                 Opt_umask),
 228         fsparam_u32oct("dmask",                 Opt_dmask),
 229         fsparam_u32oct("fmask",                 Opt_fmask),
 230         fsparam_u32oct("allow_utime",           Opt_allow_utime),
 231         fsparam_string("iocharset",             Opt_charset),
 232         fsparam_enum("errors",                  Opt_errors, exfat_param_enums),
 233         fsparam_flag("discard",                 Opt_discard),
 234         fsparam_s32("time_offset",              Opt_time_offset),
 235         {}
 236 };
 237
 238 static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
 239 {
 240         struct exfat_sb_info *sbi = fc->s_fs_info;
 241         struct exfat_mount_options *opts = &sbi->options;
 242         struct fs_parse_result result;
 243         int opt;
 244
 245         opt = fs_parse(fc, exfat_parameters, param, &result);
 246         if (opt < 0)
 247                 return opt;
 248
 249         switch (opt) {
 250         case Opt_uid:
 251                 opts->fs_uid = make_kuid(current_user_ns(), result.uint_32);
 252                 break;
 253         case Opt_gid:
 254                 opts->fs_gid = make_kgid(current_user_ns(), result.uint_32);
 255                 break;
 256         case Opt_umask:
 257                 opts->fs_fmask = result.uint_32;
 258                 opts->fs_dmask = result.uint_32;
 259                 break;
 260         case Opt_dmask:
 261                 opts->fs_dmask = result.uint_32;
 262                 break;
 263         case Opt_fmask:
 264                 opts->fs_fmask = result.uint_32;
 265                 break;
 266         case Opt_allow_utime:
 267                 opts->allow_utime = result.uint_32 & 0022;
 268                 break;
 269         case Opt_charset:
 270                 exfat_free_iocharset(sbi);
 271                 opts->iocharset = kstrdup(param->string, GFP_KERNEL);
 272                 if (!opts->iocharset)
 273                         return -ENOMEM;
 274                 break;
 275         case Opt_errors:
 276                 opts->errors = result.uint_32;
 277                 break;
 278         case Opt_discard:
 279                 opts->discard = 1;
 280                 break;
 281         case Opt_time_offset:
 282                 /*
 283                  * Make the limit 24 just in case someone invents something
 284                  * unusual.
 285                  */
 286                 if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
 287                         return -EINVAL;
 288                 opts->time_offset = result.int_32;
 289                 break;
 290         default:
 291                 return -EINVAL;
 292         }
 293
 294         return 0;
 295 }
 296
 297 static void exfat_hash_init(struct super_block *sb)
 298 {
 299         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 300         int i;
 301
 302         spin_lock_init(&sbi->inode_hash_lock);
 303         for (i = 0; i < EXFAT_HASH_SIZE; i++)
 304                 INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
 305 }
 306
 307 static int exfat_read_root(struct inode *inode)
 308 {
 309         struct super_block *sb = inode->i_sb;
 310         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 311         struct exfat_inode_info *ei = EXFAT_I(inode);
 312         struct exfat_chain cdir;
 313         int num_subdirs, num_clu = 0;
 314
 315         exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
 316         ei->entry = -1;
 317         ei->start_clu = sbi->root_dir;
 318         ei->flags = ALLOC_FAT_CHAIN;
 319         ei->type = TYPE_DIR;
 320         ei->version = 0;
 321         ei->rwoffset = 0;
 322         ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
 323         ei->hint_stat.eidx = 0;
 324         ei->hint_stat.clu = sbi->root_dir;
 325         ei->hint_femp.eidx = EXFAT_HINT_NONE;
 326
 327         exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
 328         if (exfat_count_num_clusters(sb, &cdir, &num_clu))
 329                 return -EIO;
 330         i_size_write(inode, num_clu << sbi->cluster_size_bits);
 331
 332         num_subdirs = exfat_count_dir_entries(sb, &cdir);
 333         if (num_subdirs < 0)
 334                 return -EIO;
 335         set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
 336
 337         inode->i_uid = sbi->options.fs_uid;
 338         inode->i_gid = sbi->options.fs_gid;
 339         inode_inc_iversion(inode);
 340         inode->i_generation = 0;
 341         inode->i_mode = exfat_make_mode(sbi, ATTR_SUBDIR, 0777);
 342         inode->i_op = &exfat_dir_inode_operations;
 343         inode->i_fop = &exfat_dir_operations;
 344
 345         inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1))
 346                         & ~(sbi->cluster_size - 1)) >> inode->i_blkbits;
 347         EXFAT_I(inode)->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
 348         EXFAT_I(inode)->i_size_aligned = i_size_read(inode);
 349         EXFAT_I(inode)->i_size_ondisk = i_size_read(inode);
 350
 351         exfat_save_attr(inode, ATTR_SUBDIR);
 352         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
 353                 current_time(inode);
 354         exfat_cache_init_inode(inode);
 355         return 0;
 356 }
 357
 358 static struct pbr *exfat_read_pbr_with_logical_sector(struct super_block *sb,
 359                 struct buffer_head **prev_bh)
 360 {
 361         struct pbr *p_pbr = (struct pbr *) (*prev_bh)->b_data;
 362         unsigned short logical_sect = 0;
 363
 364         logical_sect = 1 << p_pbr->bsx.f64.sect_size_bits;
 365
 366         if (!is_power_of_2(logical_sect) ||
 367             logical_sect < 512 || logical_sect > 4096) {
 368                 exfat_msg(sb, KERN_ERR, "bogus logical sector size %u",
 369                                 logical_sect);
 370                 return NULL;
 371         }
 372
 373         if (logical_sect < sb->s_blocksize) {
 374                 exfat_msg(sb, KERN_ERR,
 375                         "logical sector size too small for device (logical sector size = %u)",
 376                         logical_sect);
 377                 return NULL;
 378         }
 379
 380         if (logical_sect > sb->s_blocksize) {
 381                 struct buffer_head *bh = NULL;
 382
 383                 __brelse(*prev_bh);
 384                 *prev_bh = NULL;
 385
 386                 if (!sb_set_blocksize(sb, logical_sect)) {
 387                         exfat_msg(sb, KERN_ERR,
 388                                 "unable to set blocksize %u", logical_sect);
 389                         return NULL;
 390                 }
 391                 bh = sb_bread(sb, 0);
 392                 if (!bh) {
 393                         exfat_msg(sb, KERN_ERR,
 394                                 "unable to read boot sector (logical sector size = %lu)",
 395                                 sb->s_blocksize);
 396                         return NULL;
 397                 }
 398
 399                 *prev_bh = bh;
 400                 p_pbr = (struct pbr *) bh->b_data;
 401         }
 402         return p_pbr;
 403 }
 404
 405 /* mount the file system volume */
 406 static int __exfat_fill_super(struct super_block *sb)
 407 {
 408         int ret;
 409         struct pbr *p_pbr;
 410         struct pbr64 *p_bpb;
 411         struct buffer_head *bh;
 412         struct exfat_sb_info *sbi = EXFAT_SB(sb);
 413
 414         /* set block size to read super block */
 415         sb_min_blocksize(sb, 512);
 416
 417         /* read boot sector */
 418         bh = sb_bread(sb, 0);
 419         if (!bh) {
 420                 exfat_msg(sb, KERN_ERR, "unable to read boot sector");
 421                 return -EIO;
 422         }
 423
 424         /* PRB is read */
 425         p_pbr = (struct pbr *)bh->b_data;
 426
 427         /* check the validity of PBR */
 428         if (le16_to_cpu((p_pbr->signature)) != PBR_SIGNATURE) {
 429                 exfat_msg(sb, KERN_ERR, "invalid boot record signature");
 430                 ret = -EINVAL;
 431                 goto free_bh;
 432         }
 433
 434
 435         /* check logical sector size */
 436         p_pbr = exfat_read_pbr_with_logical_sector(sb, &bh);
 437         if (!p_pbr) {
 438                 ret = -EIO;
 439                 goto free_bh;
 440         }
 441
 442         /*
 443          * res_zero field must be filled with zero to prevent mounting
 444          * from FAT volume.
 445          */
 446         if (memchr_inv(p_pbr->bpb.f64.res_zero, 0,
 447                         sizeof(p_pbr->bpb.f64.res_zero))) {
 448                 ret = -EINVAL;
 449                 goto free_bh;
 450         }
 451
 452         p_bpb = (struct pbr64 *)p_pbr;
 453         if (!p_bpb->bsx.num_fats) {
 454                 exfat_msg(sb, KERN_ERR, "bogus number of FAT structure");
 455                 ret = -EINVAL;
 456                 goto free_bh;
 457         }
 458
 459         sbi->sect_per_clus = 1 << p_bpb->bsx.sect_per_clus_bits;
 460         sbi->sect_per_clus_bits = p_bpb->bsx.sect_per_clus_bits;
 461         sbi->cluster_size_bits = sbi->sect_per_clus_bits + sb->s_blocksize_bits;
 462         sbi->cluster_size = 1 << sbi->cluster_size_bits;
 463         sbi->num_FAT_sectors = le32_to_cpu(p_bpb->bsx.fat_length);
 464         sbi->FAT1_start_sector = le32_to_cpu(p_bpb->bsx.fat_offset);
 465         sbi->FAT2_start_sector = p_bpb->bsx.num_fats == 1 ?
 466                 sbi->FAT1_start_sector :
 467                         sbi->FAT1_start_sector + sbi->num_FAT_sectors;
 468         sbi->data_start_sector = le32_to_cpu(p_bpb->bsx.clu_offset);
 469         sbi->num_sectors = le64_to_cpu(p_bpb->bsx.vol_length);
 470         /* because the cluster index starts with 2 */
 471         sbi->num_clusters = le32_to_cpu(p_bpb->bsx.clu_count) +
 472                 EXFAT_RESERVED_CLUSTERS;
 473
 474         sbi->root_dir = le32_to_cpu(p_bpb->bsx.root_cluster);
 475         sbi->dentries_per_clu = 1 <<
 476                 (sbi->cluster_size_bits - DENTRY_SIZE_BITS);
 477
 478         sbi->vol_flag = le16_to_cpu(p_bpb->bsx.vol_flags);
 479         sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
 480         sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED;
 481
 482         if (le16_to_cpu(p_bpb->bsx.vol_flags) & VOL_DIRTY) {
 483                 sbi->vol_flag |= VOL_DIRTY;
 484                 exfat_msg(sb, KERN_WARNING,
 485                         "Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
 486         }
 487
 488         /* exFAT file size is limited by a disk volume size */
 489         sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) <<
 490                 sbi->cluster_size_bits;
 491
 492         ret = exfat_create_upcase_table(sb);
 493         if (ret) {
 494                 exfat_msg(sb, KERN_ERR, "failed to load upcase table");
 495                 goto free_bh;
 496         }
 497
 498         ret = exfat_load_bitmap(sb);
 499         if (ret) {
 500                 exfat_msg(sb, KERN_ERR, "failed to load alloc-bitmap");
 501                 goto free_upcase_table;
 502         }
 503
 504         ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
 505         if (ret) {
 506                 exfat_msg(sb, KERN_ERR, "failed to scan clusters");
 507                 goto free_alloc_bitmap;
 508         }
 509
 510         return 0;
 511
 512 free_alloc_bitmap:
 513         exfat_free_bitmap(sbi);
 514 free_upcase_table:
 515         exfat_free_upcase_table(sbi);
 516 free_bh:
 517         brelse(bh);
 518         return ret;
 519 }
 520
 521 static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 522 {
 523         struct exfat_sb_info *sbi = sb->s_fs_info;
 524         struct exfat_mount_options *opts = &sbi->options;
 525         struct inode *root_inode;
 526         int err;
 527
 528         if (opts->allow_utime == (unsigned short)-1)
 529                 opts->allow_utime = ~opts->fs_dmask & 0022;
 530
 531         if (opts->discard) {
 532                 struct request_queue *q = bdev_get_queue(sb->s_bdev);
 533
 534                 if (!blk_queue_discard(q))
 535                         exfat_msg(sb, KERN_WARNING,
 536                                 "mounting with \"discard\" option, but the device does not support discard");
 537                 opts->discard = 0;
 538         }
 539
 540         sb->s_flags |= SB_NODIRATIME;
 541         sb->s_magic = EXFAT_SUPER_MAGIC;
 542         sb->s_op = &exfat_sops;
 543
 544         sb->s_time_gran = 1;
 545         sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
 546         sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
 547
 548         err = __exfat_fill_super(sb);
 549         if (err) {
 550                 exfat_msg(sb, KERN_ERR, "failed to recognize exfat type");
 551                 goto check_nls_io;
 552         }
 553
 554         /* set up enough so that it can read an inode */
 555         exfat_hash_init(sb);
 556
 557         if (!strcmp(sbi->options.iocharset, "utf8"))
 558                 opts->utf8 = 1;
 559         else {
 560                 sbi->nls_io = load_nls(sbi->options.iocharset);
 561                 if (!sbi->nls_io) {
 562                         exfat_msg(sb, KERN_ERR, "IO charset %s not found",
 563                                         sbi->options.iocharset);
 564                         err = -EINVAL;
 565                         goto free_table;
 566                 }
 567         }
 568
 569         if (sbi->options.utf8)
 570                 sb->s_d_op = &exfat_utf8_dentry_ops;
 571         else
 572                 sb->s_d_op = &exfat_dentry_ops;
 573
 574         root_inode = new_inode(sb);
 575         if (!root_inode) {
 576                 exfat_msg(sb, KERN_ERR, "failed to allocate root inode.");
 577                 err = -ENOMEM;
 578                 goto free_table;
 579         }
 580
 581         root_inode->i_ino = EXFAT_ROOT_INO;
 582         inode_set_iversion(root_inode, 1);
 583         err = exfat_read_root(root_inode);
 584         if (err) {
 585                 exfat_msg(sb, KERN_ERR, "failed to initialize root inode.");
 586                 goto put_inode;
 587         }
 588
 589         exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
 590         insert_inode_hash(root_inode);
 591
 592         sb->s_root = d_make_root(root_inode);
 593         if (!sb->s_root) {
 594                 exfat_msg(sb, KERN_ERR, "failed to get the root dentry");
 595                 err = -ENOMEM;
 596                 goto put_inode;
 597         }
 598
 599         return 0;
 600
 601 put_inode:
 602         iput(root_inode);
 603         sb->s_root = NULL;
 604
 605 free_table:
 606         exfat_free_upcase_table(sbi);
 607         exfat_free_bitmap(sbi);
 608
 609 check_nls_io:
 610         unload_nls(sbi->nls_io);
 611         exfat_free_iocharset(sbi);
 612         sb->s_fs_info = NULL;
 613         kfree(sbi);
 614         return err;
 615 }
 616
 617 static int exfat_get_tree(struct fs_context *fc)
 618 {
 619         return get_tree_bdev(fc, exfat_fill_super);
 620 }
 621
 622 static void exfat_free(struct fs_context *fc)
 623 {
 624         kfree(fc->s_fs_info);
 625 }
 626
 627 static const struct fs_context_operations exfat_context_ops = {
 628         .parse_param    = exfat_parse_param,
 629         .get_tree       = exfat_get_tree,
 630         .free           = exfat_free,
 631 };
 632
 633 static int exfat_init_fs_context(struct fs_context *fc)
 634 {
 635         struct exfat_sb_info *sbi;
 636
 637         sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
 638         if (!sbi)
 639                 return -ENOMEM;
 640
 641         mutex_init(&sbi->s_lock);
 642         ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
 643                         DEFAULT_RATELIMIT_BURST);
 644
 645         sbi->options.fs_uid = current_uid();
 646         sbi->options.fs_gid = current_gid();
 647         sbi->options.fs_fmask = current->fs->umask;
 648         sbi->options.fs_dmask = current->fs->umask;
 649         sbi->options.allow_utime = -1;
 650         sbi->options.iocharset = exfat_default_iocharset;
 651         sbi->options.errors = EXFAT_ERRORS_RO;
 652
 653         fc->s_fs_info = sbi;
 654         fc->ops = &exfat_context_ops;
 655         return 0;
 656 }
 657
 658 static struct file_system_type exfat_fs_type = {
 659         .owner                  = THIS_MODULE,
 660         .name                   = "exfat",
 661         .init_fs_context        = exfat_init_fs_context,
 662         .parameters             = exfat_parameters,
 663         .kill_sb                = kill_block_super,
 664         .fs_flags               = FS_REQUIRES_DEV,
 665 };
 666
 667 static void exfat_inode_init_once(void *foo)
 668 {
 669         struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
 670
 671         INIT_HLIST_NODE(&ei->i_hash_fat);
 672         inode_init_once(&ei->vfs_inode);
 673 }
 674
 675 static int __init init_exfat_fs(void)
 676 {
 677         int err;
 678
 679         err = exfat_cache_init();
 680         if (err)
 681                 return err;
 682
 683         exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
 684                         sizeof(struct exfat_inode_info),
 685                         0, SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
 686                         exfat_inode_init_once);
 687         if (!exfat_inode_cachep) {
 688                 err = -ENOMEM;
 689                 goto shutdown_cache;
 690         }
 691
 692         err = register_filesystem(&exfat_fs_type);
 693         if (err)
 694                 goto destroy_cache;
 695
 696         return 0;
 697
 698 destroy_cache:
 699         kmem_cache_destroy(exfat_inode_cachep);
 700 shutdown_cache:
 701         exfat_cache_shutdown();
 702         return err;
 703 }
 704
 705 static void __exit exit_exfat_fs(void)
 706 {
 707         /*
 708          * Make sure all delayed rcu free inodes are flushed before we
 709          * destroy cache.
 710          */
 711         rcu_barrier();
 712         kmem_cache_destroy(exfat_inode_cachep);
 713         unregister_filesystem(&exfat_fs_type);
 714         exfat_cache_shutdown();
 715 }
 716
 717 module_init(init_exfat_fs);
 718 module_exit(exit_exfat_fs);
 719
 720 MODULE_LICENSE("GPL");
 721 MODULE_DESCRIPTION("exFAT filesystem support");
 722 MODULE_AUTHOR("Samsung Electronics Co., Ltd.");