1 files changed, 846 insertions, 0 deletions

diff --git a/fs/exfat/super.c b/fs/exfat/super.c
new file mode 100644
index 000000000000..35f0305cd493
--- /dev/null
+++ b/fs/exfat/super.c
@@ -0,0 +1,846 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/time.h>
+#include <linux/mount.h>
+#include <linux/cred.h>
+#include <linux/statfs.h>
+#include <linux/seq_file.h>
+#include <linux/blkdev.h>
+#include <linux/fs_struct.h>
+#include <linux/iversion.h>
+#include <linux/nls.h>
+#include <linux/buffer_head.h>
+#include <linux/magic.h>
+
+#include "exfat_raw.h"
+#include "exfat_fs.h"
+
+static char exfat_default_iocharset[] = CONFIG_EXFAT_DEFAULT_IOCHARSET;
+static struct kmem_cache *exfat_inode_cachep;
+
+static void exfat_free_iocharset(struct exfat_sb_info *sbi)
+{
+	if (sbi->options.iocharset != exfat_default_iocharset)
+		kfree(sbi->options.iocharset);
+}
+
+static void exfat_delayed_free(struct rcu_head *p)
+{
+	struct exfat_sb_info *sbi = container_of(p, struct exfat_sb_info, rcu);
+
+	unload_nls(sbi->nls_io);
+	exfat_free_iocharset(sbi);
+	exfat_free_upcase_table(sbi);
+	kfree(sbi);
+}
+
+static void exfat_put_super(struct super_block *sb)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	mutex_lock(&sbi->s_lock);
+	exfat_free_bitmap(sbi);
+	brelse(sbi->boot_bh);
+	mutex_unlock(&sbi->s_lock);
+
+	call_rcu(&sbi->rcu, exfat_delayed_free);
+}
+
+static int exfat_sync_fs(struct super_block *sb, int wait)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	int err = 0;
+
+	if (!wait)
+		return 0;
+
+	/* If there are some dirty buffers in the bdev inode */
+	mutex_lock(&sbi->s_lock);
+	sync_blockdev(sb->s_bdev);
+	if (exfat_clear_volume_dirty(sb))
+		err = -EIO;
+	mutex_unlock(&sbi->s_lock);
+	return err;
+}
+
+static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
+
+	if (sbi->used_clusters == EXFAT_CLUSTERS_UNTRACKED) {
+		mutex_lock(&sbi->s_lock);
+		if (exfat_count_used_clusters(sb, &sbi->used_clusters)) {
+			mutex_unlock(&sbi->s_lock);
+			return -EIO;
+		}
+		mutex_unlock(&sbi->s_lock);
+	}
+
+	buf->f_type = sb->s_magic;
+	buf->f_bsize = sbi->cluster_size;
+	buf->f_blocks = sbi->num_clusters - 2; /* clu 0 & 1 */
+	buf->f_bfree = buf->f_blocks - sbi->used_clusters;
+	buf->f_bavail = buf->f_bfree;
+	buf->f_fsid = u64_to_fsid(id);
+	/* Unicode utf16 255 characters */
+	buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE;
+	return 0;
+}
+
+static int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flags)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct boot_sector *p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
+
+	/* retain persistent-flags */
+	new_flags |= sbi->vol_flags_persistent;
+
+	/* flags are not changed */
+	if (sbi->vol_flags == new_flags)
+		return 0;
+
+	sbi->vol_flags = new_flags;
+
+	/* skip updating volume dirty flag,
+	 * if this volume has been mounted with read-only
+	 */
+	if (sb_rdonly(sb))
+		return 0;
+
+	p_boot->vol_flags = cpu_to_le16(new_flags);
+
+	set_buffer_uptodate(sbi->boot_bh);
+	mark_buffer_dirty(sbi->boot_bh);
+
+	__sync_dirty_buffer(sbi->boot_bh, REQ_SYNC | REQ_FUA | REQ_PREFLUSH);
+
+	return 0;
+}
+
+int exfat_set_volume_dirty(struct super_block *sb)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	return exfat_set_vol_flags(sb, sbi->vol_flags | VOLUME_DIRTY);
+}
+
+int exfat_clear_volume_dirty(struct super_block *sb)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	return exfat_set_vol_flags(sb, sbi->vol_flags & ~VOLUME_DIRTY);
+}
+
+static int exfat_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct super_block *sb = root->d_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_mount_options *opts = &sbi->options;
+
+	/* Show partition info */
+	if (!uid_eq(opts->fs_uid, GLOBAL_ROOT_UID))
+		seq_printf(m, ",uid=%u",
+				from_kuid_munged(&init_user_ns, opts->fs_uid));
+	if (!gid_eq(opts->fs_gid, GLOBAL_ROOT_GID))
+		seq_printf(m, ",gid=%u",
+				from_kgid_munged(&init_user_ns, opts->fs_gid));
+	seq_printf(m, ",fmask=%04o,dmask=%04o", opts->fs_fmask, opts->fs_dmask);
+	if (opts->allow_utime)
+		seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
+	if (opts->utf8)
+		seq_puts(m, ",iocharset=utf8");
+	else if (sbi->nls_io)
+		seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
+	if (opts->errors == EXFAT_ERRORS_CONT)
+		seq_puts(m, ",errors=continue");
+	else if (opts->errors == EXFAT_ERRORS_PANIC)
+		seq_puts(m, ",errors=panic");
+	else
+		seq_puts(m, ",errors=remount-ro");
+	if (opts->discard)
+		seq_puts(m, ",discard");
+	if (opts->keep_last_dots)
+		seq_puts(m, ",keep_last_dots");
+	if (opts->sys_tz)
+		seq_puts(m, ",sys_tz");
+	else if (opts->time_offset)
+		seq_printf(m, ",time_offset=%d", opts->time_offset);
+	return 0;
+}
+
+static struct inode *exfat_alloc_inode(struct super_block *sb)
+{
+	struct exfat_inode_info *ei;
+
+	ei = alloc_inode_sb(sb, exfat_inode_cachep, GFP_NOFS);
+	if (!ei)
+		return NULL;
+
+	init_rwsem(&ei->truncate_lock);
+	return &ei->vfs_inode;
+}
+
+static void exfat_free_inode(struct inode *inode)
+{
+	kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));
+}
+
+static const struct super_operations exfat_sops = {
+	.alloc_inode	= exfat_alloc_inode,
+	.free_inode	= exfat_free_inode,
+	.write_inode	= exfat_write_inode,
+	.evict_inode	= exfat_evict_inode,
+	.put_super	= exfat_put_super,
+	.sync_fs	= exfat_sync_fs,
+	.statfs		= exfat_statfs,
+	.show_options	= exfat_show_options,
+};
+
+enum {
+	Opt_uid,
+	Opt_gid,
+	Opt_umask,
+	Opt_dmask,
+	Opt_fmask,
+	Opt_allow_utime,
+	Opt_charset,
+	Opt_errors,
+	Opt_discard,
+	Opt_keep_last_dots,
+	Opt_sys_tz,
+	Opt_time_offset,
+
+	/* Deprecated options */
+	Opt_utf8,
+	Opt_debug,
+	Opt_namecase,
+	Opt_codepage,
+};
+
+static const struct constant_table exfat_param_enums[] = {
+	{ "continue",		EXFAT_ERRORS_CONT },
+	{ "panic",		EXFAT_ERRORS_PANIC },
+	{ "remount-ro",		EXFAT_ERRORS_RO },
+	{}
+};
+
+static const struct fs_parameter_spec exfat_parameters[] = {
+	fsparam_u32("uid",			Opt_uid),
+	fsparam_u32("gid",			Opt_gid),
+	fsparam_u32oct("umask",			Opt_umask),
+	fsparam_u32oct("dmask",			Opt_dmask),
+	fsparam_u32oct("fmask",			Opt_fmask),
+	fsparam_u32oct("allow_utime",		Opt_allow_utime),
+	fsparam_string("iocharset",		Opt_charset),
+	fsparam_enum("errors",			Opt_errors, exfat_param_enums),
+	fsparam_flag("discard",			Opt_discard),
+	fsparam_flag("keep_last_dots",		Opt_keep_last_dots),
+	fsparam_flag("sys_tz",			Opt_sys_tz),
+	fsparam_s32("time_offset",		Opt_time_offset),
+	__fsparam(NULL, "utf8",			Opt_utf8, fs_param_deprecated,
+		  NULL),
+	__fsparam(NULL, "debug",		Opt_debug, fs_param_deprecated,
+		  NULL),
+	__fsparam(fs_param_is_u32, "namecase",	Opt_namecase,
+		  fs_param_deprecated, NULL),
+	__fsparam(fs_param_is_u32, "codepage",	Opt_codepage,
+		  fs_param_deprecated, NULL),
+	{}
+};
+
+static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct exfat_sb_info *sbi = fc->s_fs_info;
+	struct exfat_mount_options *opts = &sbi->options;
+	struct fs_parse_result result;
+	int opt;
+
+	opt = fs_parse(fc, exfat_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_uid:
+		opts->fs_uid = make_kuid(current_user_ns(), result.uint_32);
+		break;
+	case Opt_gid:
+		opts->fs_gid = make_kgid(current_user_ns(), result.uint_32);
+		break;
+	case Opt_umask:
+		opts->fs_fmask = result.uint_32;
+		opts->fs_dmask = result.uint_32;
+		break;
+	case Opt_dmask:
+		opts->fs_dmask = result.uint_32;
+		break;
+	case Opt_fmask:
+		opts->fs_fmask = result.uint_32;
+		break;
+	case Opt_allow_utime:
+		opts->allow_utime = result.uint_32 & 0022;
+		break;
+	case Opt_charset:
+		exfat_free_iocharset(sbi);
+		opts->iocharset = param->string;
+		param->string = NULL;
+		break;
+	case Opt_errors:
+		opts->errors = result.uint_32;
+		break;
+	case Opt_discard:
+		opts->discard = 1;
+		break;
+	case Opt_keep_last_dots:
+		opts->keep_last_dots = 1;
+		break;
+	case Opt_sys_tz:
+		opts->sys_tz = 1;
+		break;
+	case Opt_time_offset:
+		/*
+		 * Make the limit 24 just in case someone invents something
+		 * unusual.
+		 */
+		if (result.int_32 < -24 * 60 || result.int_32 > 24 * 60)
+			return -EINVAL;
+		opts->time_offset = result.int_32;
+		break;
+	case Opt_utf8:
+	case Opt_debug:
+	case Opt_namecase:
+	case Opt_codepage:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void exfat_hash_init(struct super_block *sb)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	int i;
+
+	spin_lock_init(&sbi->inode_hash_lock);
+	for (i = 0; i < EXFAT_HASH_SIZE; i++)
+		INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
+}
+
+static int exfat_read_root(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct exfat_inode_info *ei = EXFAT_I(inode);
+	struct exfat_chain cdir;
+	int num_subdirs, num_clu = 0;
+
+	exfat_chain_set(&ei->dir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
+	ei->entry = -1;
+	ei->start_clu = sbi->root_dir;
+	ei->flags = ALLOC_FAT_CHAIN;
+	ei->type = TYPE_DIR;
+	ei->version = 0;
+	ei->hint_bmap.off = EXFAT_EOF_CLUSTER;
+	ei->hint_stat.eidx = 0;
+	ei->hint_stat.clu = sbi->root_dir;
+	ei->hint_femp.eidx = EXFAT_HINT_NONE;
+
+	exfat_chain_set(&cdir, sbi->root_dir, 0, ALLOC_FAT_CHAIN);
+	if (exfat_count_num_clusters(sb, &cdir, &num_clu))
+		return -EIO;
+	i_size_write(inode, num_clu << sbi->cluster_size_bits);
+
+	num_subdirs = exfat_count_dir_entries(sb, &cdir);
+	if (num_subdirs < 0)
+		return -EIO;
+	set_nlink(inode, num_subdirs + EXFAT_MIN_SUBDIR);
+
+	inode->i_uid = sbi->options.fs_uid;
+	inode->i_gid = sbi->options.fs_gid;
+	inode_inc_iversion(inode);
+	inode->i_generation = 0;
+	inode->i_mode = exfat_make_mode(sbi, ATTR_SUBDIR, 0777);
+	inode->i_op = &exfat_dir_inode_operations;
+	inode->i_fop = &exfat_dir_operations;
+
+	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >>
+				inode->i_blkbits;
+	ei->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
+	ei->i_size_aligned = i_size_read(inode);
+	ei->i_size_ondisk = i_size_read(inode);
+
+	exfat_save_attr(inode, ATTR_SUBDIR);
+	inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
+		current_time(inode);
+	exfat_truncate_atime(&inode->i_atime);
+	return 0;
+}
+
+static int exfat_calibrate_blocksize(struct super_block *sb, int logical_sect)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	if (!is_power_of_2(logical_sect)) {
+		exfat_err(sb, "bogus logical sector size %u", logical_sect);
+		return -EIO;
+	}
+
+	if (logical_sect < sb->s_blocksize) {
+		exfat_err(sb, "logical sector size too small for device (logical sector size = %u)",
+			  logical_sect);
+		return -EIO;
+	}
+
+	if (logical_sect > sb->s_blocksize) {
+		brelse(sbi->boot_bh);
+		sbi->boot_bh = NULL;
+
+		if (!sb_set_blocksize(sb, logical_sect)) {
+			exfat_err(sb, "unable to set blocksize %u",
+				  logical_sect);
+			return -EIO;
+		}
+		sbi->boot_bh = sb_bread(sb, 0);
+		if (!sbi->boot_bh) {
+			exfat_err(sb, "unable to read boot sector (logical sector size = %lu)",
+				  sb->s_blocksize);
+			return -EIO;
+		}
+	}
+	return 0;
+}
+
+static int exfat_read_boot_sector(struct super_block *sb)
+{
+	struct boot_sector *p_boot;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	/* set block size to read super block */
+	sb_min_blocksize(sb, 512);
+
+	/* read boot sector */
+	sbi->boot_bh = sb_bread(sb, 0);
+	if (!sbi->boot_bh) {
+		exfat_err(sb, "unable to read boot sector");
+		return -EIO;
+	}
+	p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
+
+	/* check the validity of BOOT */
+	if (le16_to_cpu((p_boot->signature)) != BOOT_SIGNATURE) {
+		exfat_err(sb, "invalid boot record signature");
+		return -EINVAL;
+	}
+
+	if (memcmp(p_boot->fs_name, STR_EXFAT, BOOTSEC_FS_NAME_LEN)) {
+		exfat_err(sb, "invalid fs_name"); /* fs_name may unprintable */
+		return -EINVAL;
+	}
+
+	/*
+	 * must_be_zero field must be filled with zero to prevent mounting
+	 * from FAT volume.
+	 */
+	if (memchr_inv(p_boot->must_be_zero, 0, sizeof(p_boot->must_be_zero)))
+		return -EINVAL;
+
+	if (p_boot->num_fats != 1 && p_boot->num_fats != 2) {
+		exfat_err(sb, "bogus number of FAT structure");
+		return -EINVAL;
+	}
+
+	/*
+	 * sect_size_bits could be at least 9 and at most 12.
+	 */
+	if (p_boot->sect_size_bits < EXFAT_MIN_SECT_SIZE_BITS ||
+	    p_boot->sect_size_bits > EXFAT_MAX_SECT_SIZE_BITS) {
+		exfat_err(sb, "bogus sector size bits : %u",
+				p_boot->sect_size_bits);
+		return -EINVAL;
+	}
+
+	/*
+	 * sect_per_clus_bits could be at least 0 and at most 25 - sect_size_bits.
+	 */
+	if (p_boot->sect_per_clus_bits > EXFAT_MAX_SECT_PER_CLUS_BITS(p_boot)) {
+		exfat_err(sb, "bogus sectors bits per cluster : %u",
+				p_boot->sect_per_clus_bits);
+		return -EINVAL;
+	}
+
+	sbi->sect_per_clus = 1 << p_boot->sect_per_clus_bits;
+	sbi->sect_per_clus_bits = p_boot->sect_per_clus_bits;
+	sbi->cluster_size_bits = p_boot->sect_per_clus_bits +
+		p_boot->sect_size_bits;
+	sbi->cluster_size = 1 << sbi->cluster_size_bits;
+	sbi->num_FAT_sectors = le32_to_cpu(p_boot->fat_length);
+	sbi->FAT1_start_sector = le32_to_cpu(p_boot->fat_offset);
+	sbi->FAT2_start_sector = le32_to_cpu(p_boot->fat_offset);
+	if (p_boot->num_fats == 2)
+		sbi->FAT2_start_sector += sbi->num_FAT_sectors;
+	sbi->data_start_sector = le32_to_cpu(p_boot->clu_offset);
+	sbi->num_sectors = le64_to_cpu(p_boot->vol_length);
+	/* because the cluster index starts with 2 */
+	sbi->num_clusters = le32_to_cpu(p_boot->clu_count) +
+		EXFAT_RESERVED_CLUSTERS;
+
+	sbi->root_dir = le32_to_cpu(p_boot->root_cluster);
+	sbi->dentries_per_clu = 1 <<
+		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
+
+	sbi->vol_flags = le16_to_cpu(p_boot->vol_flags);
+	sbi->vol_flags_persistent = sbi->vol_flags & (VOLUME_DIRTY | MEDIA_FAILURE);
+	sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
+	sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED;
+
+	/* check consistencies */
+	if ((u64)sbi->num_FAT_sectors << p_boot->sect_size_bits <
+	    (u64)sbi->num_clusters * 4) {
+		exfat_err(sb, "bogus fat length");
+		return -EINVAL;
+	}
+
+	if (sbi->data_start_sector <
+	    (u64)sbi->FAT1_start_sector +
+	    (u64)sbi->num_FAT_sectors * p_boot->num_fats) {
+		exfat_err(sb, "bogus data start sector");
+		return -EINVAL;
+	}
+
+	if (sbi->vol_flags & VOLUME_DIRTY)
+		exfat_warn(sb, "Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
+	if (sbi->vol_flags & MEDIA_FAILURE)
+		exfat_warn(sb, "Medium has reported failures. Some data may be lost.");
+
+	/* exFAT file size is limited by a disk volume size */
+	sb->s_maxbytes = (u64)(sbi->num_clusters - EXFAT_RESERVED_CLUSTERS) <<
+		sbi->cluster_size_bits;
+
+	/* check logical sector size */
+	if (exfat_calibrate_blocksize(sb, 1 << p_boot->sect_size_bits))
+		return -EIO;
+
+	return 0;
+}
+
+static int exfat_verify_boot_region(struct super_block *sb)
+{
+	struct buffer_head *bh = NULL;
+	u32 chksum = 0;
+	__le32 *p_sig, *p_chksum;
+	int sn, i;
+
+	/* read boot sector sub-regions */
+	for (sn = 0; sn < 11; sn++) {
+		bh = sb_bread(sb, sn);
+		if (!bh)
+			return -EIO;
+
+		if (sn != 0 && sn <= 8) {
+			/* extended boot sector sub-regions */
+			p_sig = (__le32 *)&bh->b_data[sb->s_blocksize - 4];
+			if (le32_to_cpu(*p_sig) != EXBOOT_SIGNATURE)
+				exfat_warn(sb, "Invalid exboot-signature(sector = %d): 0x%08x",
+					   sn, le32_to_cpu(*p_sig));
+		}
+
+		chksum = exfat_calc_chksum32(bh->b_data, sb->s_blocksize,
+			chksum, sn ? CS_DEFAULT : CS_BOOT_SECTOR);
+		brelse(bh);
+	}
+
+	/* boot checksum sub-regions */
+	bh = sb_bread(sb, sn);
+	if (!bh)
+		return -EIO;
+
+	for (i = 0; i < sb->s_blocksize; i += sizeof(u32)) {
+		p_chksum = (__le32 *)&bh->b_data[i];
+		if (le32_to_cpu(*p_chksum) != chksum) {
+			exfat_err(sb, "Invalid boot checksum (boot checksum : 0x%08x, checksum : 0x%08x)",
+				  le32_to_cpu(*p_chksum), chksum);
+			brelse(bh);
+			return -EINVAL;
+		}
+	}
+	brelse(bh);
+	return 0;
+}
+
+/* mount the file system volume */
+static int __exfat_fill_super(struct super_block *sb)
+{
+	int ret;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	ret = exfat_read_boot_sector(sb);
+	if (ret) {
+		exfat_err(sb, "failed to read boot sector");
+		goto free_bh;
+	}
+
+	ret = exfat_verify_boot_region(sb);
+	if (ret) {
+		exfat_err(sb, "invalid boot region");
+		goto free_bh;
+	}
+
+	ret = exfat_create_upcase_table(sb);
+	if (ret) {
+		exfat_err(sb, "failed to load upcase table");
+		goto free_bh;
+	}
+
+	ret = exfat_load_bitmap(sb);
+	if (ret) {
+		exfat_err(sb, "failed to load alloc-bitmap");
+		goto free_upcase_table;
+	}
+
+	ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
+	if (ret) {
+		exfat_err(sb, "failed to scan clusters");
+		goto free_alloc_bitmap;
+	}
+
+	return 0;
+
+free_alloc_bitmap:
+	exfat_free_bitmap(sbi);
+free_upcase_table:
+	exfat_free_upcase_table(sbi);
+free_bh:
+	brelse(sbi->boot_bh);
+	return ret;
+}
+
+static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+	struct exfat_sb_info *sbi = sb->s_fs_info;
+	struct exfat_mount_options *opts = &sbi->options;
+	struct inode *root_inode;
+	int err;
+
+	if (opts->allow_utime == (unsigned short)-1)
+		opts->allow_utime = ~opts->fs_dmask & 0022;
+
+	if (opts->discard && !bdev_max_discard_sectors(sb->s_bdev)) {
+		exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
+		opts->discard = 0;
+	}
+
+	sb->s_flags |= SB_NODIRATIME;
+	sb->s_magic = EXFAT_SUPER_MAGIC;
+	sb->s_op = &exfat_sops;
+
+	sb->s_time_gran = 10 * NSEC_PER_MSEC;
+	sb->s_time_min = EXFAT_MIN_TIMESTAMP_SECS;
+	sb->s_time_max = EXFAT_MAX_TIMESTAMP_SECS;
+
+	err = __exfat_fill_super(sb);
+	if (err) {
+		exfat_err(sb, "failed to recognize exfat type");
+		goto check_nls_io;
+	}
+
+	/* set up enough so that it can read an inode */
+	exfat_hash_init(sb);
+
+	if (!strcmp(sbi->options.iocharset, "utf8"))
+		opts->utf8 = 1;
+	else {
+		sbi->nls_io = load_nls(sbi->options.iocharset);
+		if (!sbi->nls_io) {
+			exfat_err(sb, "IO charset %s not found",
+				  sbi->options.iocharset);
+			err = -EINVAL;
+			goto free_table;
+		}
+	}
+
+	if (sbi->options.utf8)
+		sb->s_d_op = &exfat_utf8_dentry_ops;
+	else
+		sb->s_d_op = &exfat_dentry_ops;
+
+	root_inode = new_inode(sb);
+	if (!root_inode) {
+		exfat_err(sb, "failed to allocate root inode");
+		err = -ENOMEM;
+		goto free_table;
+	}
+
+	root_inode->i_ino = EXFAT_ROOT_INO;
+	inode_set_iversion(root_inode, 1);
+	err = exfat_read_root(root_inode);
+	if (err) {
+		exfat_err(sb, "failed to initialize root inode");
+		goto put_inode;
+	}
+
+	exfat_hash_inode(root_inode, EXFAT_I(root_inode)->i_pos);
+	insert_inode_hash(root_inode);
+
+	sb->s_root = d_make_root(root_inode);
+	if (!sb->s_root) {
+		exfat_err(sb, "failed to get the root dentry");
+		err = -ENOMEM;
+		goto free_table;
+	}
+
+	return 0;
+
+put_inode:
+	iput(root_inode);
+	sb->s_root = NULL;
+
+free_table:
+	exfat_free_upcase_table(sbi);
+	exfat_free_bitmap(sbi);
+	brelse(sbi->boot_bh);
+
+check_nls_io:
+	unload_nls(sbi->nls_io);
+	exfat_free_iocharset(sbi);
+	sb->s_fs_info = NULL;
+	kfree(sbi);
+	return err;
+}
+
+static int exfat_get_tree(struct fs_context *fc)
+{
+	return get_tree_bdev(fc, exfat_fill_super);
+}
+
+static void exfat_free(struct fs_context *fc)
+{
+	struct exfat_sb_info *sbi = fc->s_fs_info;
+
+	if (sbi) {
+		exfat_free_iocharset(sbi);
+		kfree(sbi);
+	}
+}
+
+static int exfat_reconfigure(struct fs_context *fc)
+{
+	fc->sb_flags |= SB_NODIRATIME;
+
+	/* volume flag will be updated in exfat_sync_fs */
+	sync_filesystem(fc->root->d_sb);
+	return 0;
+}
+
+static const struct fs_context_operations exfat_context_ops = {
+	.parse_param	= exfat_parse_param,
+	.get_tree	= exfat_get_tree,
+	.free		= exfat_free,
+	.reconfigure	= exfat_reconfigure,
+};
+
+static int exfat_init_fs_context(struct fs_context *fc)
+{
+	struct exfat_sb_info *sbi;
+
+	sbi = kzalloc(sizeof(struct exfat_sb_info), GFP_KERNEL);
+	if (!sbi)
+		return -ENOMEM;
+
+	mutex_init(&sbi->s_lock);
+	mutex_init(&sbi->bitmap_lock);
+	ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
+			DEFAULT_RATELIMIT_BURST);
+
+	sbi->options.fs_uid = current_uid();
+	sbi->options.fs_gid = current_gid();
+	sbi->options.fs_fmask = current->fs->umask;
+	sbi->options.fs_dmask = current->fs->umask;
+	sbi->options.allow_utime = -1;
+	sbi->options.iocharset = exfat_default_iocharset;
+	sbi->options.errors = EXFAT_ERRORS_RO;
+
+	fc->s_fs_info = sbi;
+	fc->ops = &exfat_context_ops;
+	return 0;
+}
+
+static struct file_system_type exfat_fs_type = {
+	.owner			= THIS_MODULE,
+	.name			= "exfat",
+	.init_fs_context	= exfat_init_fs_context,
+	.parameters		= exfat_parameters,
+	.kill_sb		= kill_block_super,
+	.fs_flags		= FS_REQUIRES_DEV,
+};
+
+static void exfat_inode_init_once(void *foo)
+{
+	struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;
+
+	spin_lock_init(&ei->cache_lru_lock);
+	ei->nr_caches = 0;
+	ei->cache_valid_id = EXFAT_CACHE_VALID + 1;
+	INIT_LIST_HEAD(&ei->cache_lru);
+	INIT_HLIST_NODE(&ei->i_hash_fat);
+	inode_init_once(&ei->vfs_inode);
+}
+
+static int __init init_exfat_fs(void)
+{
+	int err;
+
+	err = exfat_cache_init();
+	if (err)
+		return err;
+
+	exfat_inode_cachep = kmem_cache_create("exfat_inode_cache",
+			sizeof(struct exfat_inode_info),
+			0, SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
+			exfat_inode_init_once);
+	if (!exfat_inode_cachep) {
+		err = -ENOMEM;
+		goto shutdown_cache;
+	}
+
+	err = register_filesystem(&exfat_fs_type);
+	if (err)
+		goto destroy_cache;
+
+	return 0;
+
+destroy_cache:
+	kmem_cache_destroy(exfat_inode_cachep);
+shutdown_cache:
+	exfat_cache_shutdown();
+	return err;
+}
+
+static void __exit exit_exfat_fs(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(exfat_inode_cachep);
+	unregister_filesystem(&exfat_fs_type);
+	exfat_cache_shutdown();
+}
+
+module_init(init_exfat_fs);
+module_exit(exit_exfat_fs);
+
+MODULE_ALIAS_FS("exfat");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("exFAT filesystem support");
+MODULE_AUTHOR("Samsung Electronics Co., Ltd.");