diff mbox series

[v9,02/13] exfat: add super block operations

Message ID 20200102082036.29643-3-namjae.jeon@samsung.com (mailing list archive)
State New, archived
Headers show
Series add the latest exfat driver | expand

Commit Message

Namjae Jeon Jan. 2, 2020, 8:20 a.m. UTC
This adds the implementation of superblock operations for exfat.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
---
 fs/exfat/super.c | 723 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 723 insertions(+)
 create mode 100644 fs/exfat/super.c

Comments

Christoph Hellwig Jan. 8, 2020, 5:21 p.m. UTC | #1
Looks good, modulo a few nitpicks below:

Reviewed-by: Christoph Hellwig <hch@lst.de>

On Thu, Jan 02, 2020 at 04:20:25PM +0800, Namjae Jeon wrote:
> +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 == ~0u) {

Various other places use UINT_MAX here instead.  Maybe it makes sense
to add a EXFAT_CLUSTERS_UNTRACKED or similar define and use that in all
places?

> +	if ((new_flag == VOL_DIRTY) && (!buffer_dirty(sbi->pbr_bh)))

No need for both sets of inner braces.

> +static bool is_exfat(struct pbr *pbr)
> +{
> +	int i = MUST_BE_ZERO_LEN;
> +
> +	do {
> +		if (pbr->bpb.f64.res_zero[i - 1])
> +			break;
> +	} while (--i);
> +	return i ? false : true;
> +}

I find the MUST_BE_ZERO_LEN a little weird here.  Maybe that should
be something like PBP64_RESERVED_LEN?

Also I think this could be simplified by just using memchr_inv in the
caller

	if (memchr_inv(pbr->bpb.f64.res_zero, 0,
			sizeof(pbr->bpb.f64.res_zero)))
		ret = -EINVAL;
		goto free_bh;
	}

> +	/* set maximum file size for exFAT */
> +	sb->s_maxbytes = 0x7fffffffffffffffLL;

That this is setting the max size is pretty obvious.  Maybe the comment
should be updated to mention how this max file size is calculated?
Namjae Jeon Jan. 9, 2020, 11:21 p.m. UTC | #2
> Looks good, modulo a few nitpicks below:
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
Thanks!
> 
> On Thu, Jan 02, 2020 at 04:20:25PM +0800, Namjae Jeon wrote:
> > +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 == ~0u) {
> 
> Various other places use UINT_MAX here instead.  Maybe it makes sense to
> add a EXFAT_CLUSTERS_UNTRACKED or similar define and use that in all
> places?
Okay.
> 
> > +	if ((new_flag == VOL_DIRTY) && (!buffer_dirty(sbi->pbr_bh)))
> 
> No need for both sets of inner braces.
Yep.
> 
> > +static bool is_exfat(struct pbr *pbr) {
> > +	int i = MUST_BE_ZERO_LEN;
> > +
> > +	do {
> > +		if (pbr->bpb.f64.res_zero[i - 1])
> > +			break;
> > +	} while (--i);
> > +	return i ? false : true;
> > +}
> 
> I find the MUST_BE_ZERO_LEN a little weird here.  Maybe that should be
> something like PBP64_RESERVED_LEN?
Okay.

> 
> Also I think this could be simplified by just using memchr_inv in the
> caller
> 
> 	if (memchr_inv(pbr->bpb.f64.res_zero, 0,
> 			sizeof(pbr->bpb.f64.res_zero)))
> 		ret = -EINVAL;
> 		goto free_bh;
> 	}
Okay.
> 
> > +	/* set maximum file size for exFAT */
> > +	sb->s_maxbytes = 0x7fffffffffffffffLL;
> 
> That this is setting the max size is pretty obvious.  Maybe the comment
> should be updated to mention how this max file size is calculated?
I will add the comment.

Thanks for your review!
diff mbox series

Patch

diff --git a/fs/exfat/super.c b/fs/exfat/super.c
new file mode 100644
index 000000000000..bb02ee1f1b9e
--- /dev/null
+++ b/fs/exfat/super.c
@@ -0,0 +1,723 @@ 
+// 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 "exfat_raw.h"
+#include "exfat_fs.h"
+
+static char exfat_default_iocharset[] = CONFIG_EXFAT_FS_DEFAULT_IOCHARSET;
+static const char exfat_iocharset_with_utf8[] = "iso8859-1";
+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_put_super(struct super_block *sb)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	mutex_lock(&sbi->s_lock);
+	if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state))
+		sync_blockdev(sb->s_bdev);
+	exfat_set_vol_flags(sb, VOL_CLEAN);
+	exfat_free_upcase_table(sb);
+	exfat_free_bitmap(sb);
+	mutex_unlock(&sbi->s_lock);
+
+	if (sbi->nls_io) {
+		unload_nls(sbi->nls_io);
+		sbi->nls_io = NULL;
+	}
+	exfat_free_iocharset(sbi);
+	sb->s_fs_info = NULL;
+	kfree(sbi);
+}
+
+static int exfat_sync_fs(struct super_block *sb, int wait)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	int err = 0;
+
+	/* If there are some dirty buffers in the bdev inode */
+	mutex_lock(&sbi->s_lock);
+	if (test_and_clear_bit(EXFAT_SB_DIRTY, &sbi->s_state)) {
+		sync_blockdev(sb->s_bdev);
+		if (exfat_set_vol_flags(sb, VOL_CLEAN))
+			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 == ~0u) {
+		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.val[0] = (unsigned int)id;
+	buf->f_fsid.val[1] = (unsigned int)(id >> 32);
+	/* Unicode utf16 255 characters */
+	buf->f_namelen = EXFAT_MAX_FILE_LEN * NLS_MAX_CHARSET_SIZE;
+	return 0;
+}
+
+int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)
+{
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+	struct pbr64 *bpb;
+	bool sync = 0;
+
+	/* flags are not changed */
+	if (sbi->vol_flag == new_flag)
+		return 0;
+
+	sbi->vol_flag = new_flag;
+
+	/* skip updating volume dirty flag,
+	 * if this volume has been mounted with read-only
+	 */
+	if (sb_rdonly(sb))
+		return 0;
+
+	if (!sbi->pbr_bh) {
+		sbi->pbr_bh = sb_bread(sb, 0);
+		if (!sbi->pbr_bh) {
+			exfat_msg(sb, KERN_ERR, "failed to read boot sector");
+			return -ENOMEM;
+		}
+	}
+
+	bpb = (struct pbr64 *)sbi->pbr_bh->b_data;
+	bpb->bsx.vol_flags = cpu_to_le16(new_flag);
+
+	if ((new_flag == VOL_DIRTY) && (!buffer_dirty(sbi->pbr_bh)))
+		sync = true;
+	else
+		sync = false;
+
+	set_buffer_uptodate(sbi->pbr_bh);
+	mark_buffer_dirty(sbi->pbr_bh);
+
+	if (sync)
+		sync_dirty_buffer(sbi->pbr_bh);
+	return 0;
+}
+
+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 (sbi->nls_io)
+		seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
+	if (opts->utf8)
+		seq_puts(m, ",utf8");
+	seq_printf(m, ",case_sensitive=%u", opts->case_sensitive);
+	seq_printf(m, ",bps=%ld", sb->s_blocksize);
+	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");
+	return 0;
+}
+
+static struct inode *exfat_alloc_inode(struct super_block *sb)
+{
+	struct exfat_inode_info *ei;
+
+	ei = kmem_cache_alloc(exfat_inode_cachep, GFP_NOFS);
+	if (!ei)
+		return NULL;
+
+	init_rwsem(&ei->truncate_lock);
+	return &ei->vfs_inode;
+}
+
+static void exfat_destroy_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,
+	.destroy_inode = exfat_destroy_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_utf8,
+	Opt_case_sensitive,
+	Opt_errors,
+	Opt_discard,
+};
+
+static const struct fs_parameter_spec exfat_param_specs[] = {
+	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_flag("utf8",			Opt_utf8),
+	fsparam_flag("case_sensitive",		Opt_case_sensitive),
+	fsparam_enum("errors",			Opt_errors),
+	fsparam_flag("discard",			Opt_discard),
+	{}
+};
+
+static const struct fs_parameter_enum exfat_param_enums[] = {
+	{ Opt_errors,	"continue",		EXFAT_ERRORS_CONT },
+	{ Opt_errors,	"panic",		EXFAT_ERRORS_PANIC },
+	{ Opt_errors,	"remount-ro",		EXFAT_ERRORS_RO },
+	{}
+};
+
+static const struct fs_parameter_description exfat_parameters = {
+	.name		= "exfat",
+	.specs		= exfat_param_specs,
+	.enums		= exfat_param_enums,
+};
+
+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 = kstrdup(param->string, GFP_KERNEL);
+		if (!opts->iocharset)
+			return -ENOMEM;
+		break;
+	case Opt_case_sensitive:
+		opts->case_sensitive = 1;
+		break;
+	case Opt_utf8:
+		opts->utf8 = 1;
+		break;
+	case Opt_errors:
+		opts->errors = result.uint_32;
+		break;
+	case Opt_discard:
+		opts->discard = 1;
+		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->rwoffset = 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 = ((i_size_read(inode) + (sbi->cluster_size - 1))
+			& ~(sbi->cluster_size - 1)) >> inode->i_blkbits;
+	EXFAT_I(inode)->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
+	EXFAT_I(inode)->i_size_aligned = i_size_read(inode);
+	EXFAT_I(inode)->i_size_ondisk = i_size_read(inode);
+
+	exfat_save_attr(inode, ATTR_SUBDIR);
+	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
+	exfat_cache_init_inode(inode);
+	return 0;
+}
+
+static bool is_exfat(struct pbr *pbr)
+{
+	int i = MUST_BE_ZERO_LEN;
+
+	do {
+		if (pbr->bpb.f64.res_zero[i - 1])
+			break;
+	} while (--i);
+	return i ? false : true;
+}
+
+static struct pbr *exfat_read_pbr_with_logical_sector(struct super_block *sb,
+		struct buffer_head **prev_bh)
+{
+	struct pbr *p_pbr = (struct pbr *) (*prev_bh)->b_data;
+	unsigned short logical_sect = 0;
+
+	logical_sect = 1 << p_pbr->bsx.f64.sect_size_bits;
+
+	if (!is_power_of_2(logical_sect) ||
+	    logical_sect < 512 || logical_sect > 4096) {
+		exfat_msg(sb, KERN_ERR, "bogus logical sector size %u",
+				logical_sect);
+		return NULL;
+	}
+
+	if (logical_sect < sb->s_blocksize) {
+		exfat_msg(sb, KERN_ERR,
+			"logical sector size too small for device (logical sector size = %u)",
+			logical_sect);
+		return NULL;
+	}
+
+	if (logical_sect > sb->s_blocksize) {
+		struct buffer_head *bh = NULL;
+
+		__brelse(*prev_bh);
+		*prev_bh = NULL;
+
+		if (!sb_set_blocksize(sb, logical_sect)) {
+			exfat_msg(sb, KERN_ERR,
+				"unable to set blocksize %u", logical_sect);
+			return NULL;
+		}
+		bh = sb_bread(sb, 0);
+		if (!bh) {
+			exfat_msg(sb, KERN_ERR,
+				"unable to read boot sector (logical sector size = %lu)",
+				sb->s_blocksize);
+			return NULL;
+		}
+
+		*prev_bh = bh;
+		p_pbr = (struct pbr *) bh->b_data;
+	}
+	return p_pbr;
+}
+
+/* mount the file system volume */
+static int __exfat_fill_super(struct super_block *sb)
+{
+	int ret;
+	struct pbr *p_pbr;
+	struct pbr64 *p_bpb;
+	struct buffer_head *bh;
+	struct exfat_sb_info *sbi = EXFAT_SB(sb);
+
+	/* set block size to read super block */
+	sb_min_blocksize(sb, 512);
+
+	/* read boot sector */
+	bh = sb_bread(sb, 0);
+	if (!bh) {
+		exfat_msg(sb, KERN_ERR, "unable to read boot sector");
+		return -EIO;
+	}
+
+	/* PRB is read */
+	p_pbr = (struct pbr *)bh->b_data;
+
+	/* check the validity of PBR */
+	if (le16_to_cpu((p_pbr->signature)) != PBR_SIGNATURE) {
+		exfat_msg(sb, KERN_ERR, "invalid boot record signature");
+		ret = -EINVAL;
+		goto free_bh;
+	}
+
+
+	/* check logical sector size */
+	p_pbr = exfat_read_pbr_with_logical_sector(sb, &bh);
+	if (!p_pbr) {
+		ret = -EIO;
+		goto free_bh;
+	}
+
+	if (!is_exfat(p_pbr)) {
+		ret = -EINVAL;
+		goto free_bh;
+	}
+
+	/* set maximum file size for exFAT */
+	sb->s_maxbytes = 0x7fffffffffffffffLL;
+
+	p_bpb = (struct pbr64 *)p_pbr;
+	if (!p_bpb->bsx.num_fats) {
+		exfat_msg(sb, KERN_ERR, "bogus number of FAT structure");
+		ret = -EINVAL;
+		goto free_bh;
+	}
+
+	sbi->sect_per_clus = 1 << p_bpb->bsx.sect_per_clus_bits;
+	sbi->sect_per_clus_bits = p_bpb->bsx.sect_per_clus_bits;
+	sbi->cluster_size_bits = sbi->sect_per_clus_bits + sb->s_blocksize_bits;
+	sbi->cluster_size = 1 << sbi->cluster_size_bits;
+	sbi->num_FAT_sectors = le32_to_cpu(p_bpb->bsx.fat_length);
+	sbi->FAT1_start_sector = le32_to_cpu(p_bpb->bsx.fat_offset);
+	sbi->FAT2_start_sector = p_bpb->bsx.num_fats == 1 ?
+		sbi->FAT1_start_sector :
+			sbi->FAT1_start_sector + sbi->num_FAT_sectors;
+	sbi->root_start_sector = le32_to_cpu(p_bpb->bsx.clu_offset);
+	sbi->data_start_sector = sbi->root_start_sector;
+	sbi->num_sectors = le64_to_cpu(p_bpb->bsx.vol_length);
+	/* because the cluster index starts with 2 */
+	sbi->num_clusters = le32_to_cpu(p_bpb->bsx.clu_count) +
+		EXFAT_RESERVED_CLUSTERS;
+
+	sbi->vol_id = le32_to_cpu(p_bpb->bsx.vol_serial);
+	sbi->root_dir = le32_to_cpu(p_bpb->bsx.root_cluster);
+	sbi->dentries_in_root = 0;
+	sbi->dentries_per_clu = 1 <<
+		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
+
+	sbi->vol_flag = le16_to_cpu(p_bpb->bsx.vol_flags);
+	sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
+	sbi->used_clusters = ~0u;
+
+	if (le16_to_cpu(p_bpb->bsx.vol_flags) & VOL_DIRTY) {
+		sbi->vol_flag |= VOL_DIRTY;
+		exfat_msg(sb, KERN_WARNING,
+			"Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
+	}
+
+	ret = exfat_create_upcase_table(sb);
+	if (ret) {
+		exfat_msg(sb, KERN_ERR, "failed to load upcase table");
+		goto free_bh;
+	}
+
+	ret = exfat_load_bitmap(sb);
+	if (ret) {
+		exfat_msg(sb, KERN_ERR, "failed to load alloc-bitmap");
+		goto free_upcase_table;
+	}
+
+	ret = exfat_count_used_clusters(sb, &sbi->used_clusters);
+	if (ret) {
+		exfat_msg(sb, KERN_ERR, "failed to scan clusters");
+		goto free_alloc_bitmap;
+	}
+
+	return 0;
+
+free_alloc_bitmap:
+	exfat_free_bitmap(sb);
+free_upcase_table:
+	exfat_free_upcase_table(sb);
+free_bh:
+	brelse(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->utf8 && strcmp(opts->iocharset, exfat_iocharset_with_utf8)) {
+		exfat_msg(sb, KERN_WARNING,
+			"utf8 enabled, \"iocharset=%s\" is recommended",
+			exfat_iocharset_with_utf8);
+	}
+
+	if (opts->discard) {
+		struct request_queue *q = bdev_get_queue(sb->s_bdev);
+
+		if (!blk_queue_discard(q))
+			exfat_msg(sb, KERN_WARNING,
+				"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_d_op = EXFAT_SB(sb)->options.case_sensitive ?
+			&exfat_dentry_ops : &exfat_ci_dentry_ops;
+
+	err = __exfat_fill_super(sb);
+	if (err) {
+		exfat_msg(sb, KERN_ERR, "failed to recognize exfat type");
+		goto check_nls_io;
+	}
+
+	/* set up enough so that it can read an inode */
+	exfat_hash_init(sb);
+
+	sbi->nls_io = load_nls(sbi->options.iocharset);
+	if (!sbi->nls_io) {
+		exfat_msg(sb, KERN_ERR, "IO charset %s not found",
+				sbi->options.iocharset);
+		err = -EINVAL;
+		goto free_table;
+	}
+
+	root_inode = new_inode(sb);
+	if (!root_inode) {
+		exfat_msg(sb, KERN_ERR, "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_msg(sb, KERN_ERR, "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_msg(sb, KERN_ERR, "failed to get the root dentry");
+		err = -ENOMEM;
+		goto put_inode;
+	}
+
+	return 0;
+
+put_inode:
+	iput(root_inode);
+	sb->s_root = NULL;
+
+free_table:
+	exfat_free_upcase_table(sb);
+	exfat_free_bitmap(sb);
+
+check_nls_io:
+	if (sbi->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)
+{
+	kfree(fc->s_fs_info);
+}
+
+static const struct fs_context_operations exfat_context_ops = {
+	.parse_param	= exfat_parse_param,
+	.get_tree	= exfat_get_tree,
+	.free		= exfat_free,
+};
+
+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);
+	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;
+
+	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)
+{
+	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_LICENSE("GPL");
+MODULE_DESCRIPTION("exFAT filesystem support");
+MODULE_AUTHOR("Samsung Electronics Co., Ltd.");