Merge tag 'exfat-for-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat

Pull exfat update from Namjae Jeon:
 "Bug fixes:
   - Fix memory leak on mount failure with iocharset= option
   - Fix incorrect update of stream entry
   - Fix cluster range validation error

  Clean-ups:
   - Remove unused code and unneeded assignment
   - Rename variables in exfat structure as specification
   - Reorganize boot sector analysis code
   - Simplify exfat_utf8_d_hash and exfat_utf8_d_cmp()
   - Optimize exfat entry cache functions
   - Improve wording of EXFAT_DEFAULT_IOCHARSET config option

 New Feature:
   - Add boot region verification"

* tag 'exfat-for-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat:
  exfat: Fix potential use after free in exfat_load_upcase_table()
  exfat: fix range validation error in alloc and free cluster
  exfat: fix incorrect update of stream entry in __exfat_truncate()
  exfat: fix memory leak in exfat_parse_param()
  exfat: remove unnecessary reassignment of p_uniname->name_len
  exfat: standardize checksum calculation
  exfat: add boot region verification
  exfat: separate the boot sector analysis
  exfat: redefine PBR as boot_sector
  exfat: optimize dir-cache
  exfat: replace 'time_ms' with 'time_cs'
  exfat: remove the assignment of 0 to bool variable
  exfat: Remove unused functions exfat_high_surrogate() and exfat_low_surrogate()
  exfat: Simplify exfat_utf8_d_hash() for code points above U+FFFF
  exfat: Improve wording of EXFAT_DEFAULT_IOCHARSET config option
  exfat: Use a more common logging style
  exfat: Simplify exfat_utf8_d_cmp() for code points above U+FFFF

12 files changed, 423 insertions, 469 deletions

diff --git a/fs/exfat/Kconfig b/fs/exfat/Kconfig
index 2d3636dc5b8c..5a65071b5ecf 100644
--- a/fs/exfat/Kconfig
+++ b/fs/exfat/Kconfig
@@ -16,6 +16,7 @@ config EXFAT_DEFAULT_IOCHARSET
 	depends on EXFAT_FS
 	help
 	  Set this to the default input/output character set to use for
-	  converting between the encoding is used for user visible filename and
-	  UTF-16 character that exfat filesystem use, and can be overridden with
-	  the "iocharset" mount option for exFAT filesystems.
+	  converting between the encoding that is used for user visible
+	  filenames and the UTF-16 character encoding that the exFAT
+	  filesystem uses.  This can be overridden with the "iocharset" mount
+	  option for the exFAT filesystems.
diff --git a/fs/exfat/balloc.c b/fs/exfat/balloc.c
index 6774a5a6ded8..4055eb00ea9b 100644
--- a/fs/exfat/balloc.c
+++ b/fs/exfat/balloc.c
@@ -58,9 +58,8 @@ static int exfat_allocate_bitmap(struct super_block *sb,
 	need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE)
 		+ 1;
 	if (need_map_size != map_size) {
-		exfat_msg(sb, KERN_ERR,
-				"bogus allocation bitmap size(need : %u, cur : %lld)",
-				need_map_size, map_size);
+		exfat_err(sb, "bogus allocation bitmap size(need : %u, cur : %lld)",
+			  need_map_size, map_size);
 		/*
 		 * Only allowed when bogus allocation
 		 * bitmap size is large
@@ -192,8 +191,7 @@ void exfat_clear_bitmap(struct inode *inode, unsigned int clu)
 			(1 << sbi->sect_per_clus_bits), GFP_NOFS, 0);
 
 		if (ret_discard == -EOPNOTSUPP) {
-			exfat_msg(sb, KERN_ERR,
-				"discard not supported by device, disabling");
+			exfat_err(sb, "discard not supported by device, disabling");
 			opts->discard = 0;
 		}
 	}
diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c
index 4b91afb0f051..de43534aa299 100644
--- a/fs/exfat/dir.c
+++ b/fs/exfat/dir.c
@@ -32,35 +32,30 @@ static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
 		struct exfat_chain *p_dir, int entry, unsigned short *uniname)
 {
 	int i;
-	struct exfat_dentry *ep;
 	struct exfat_entry_set_cache *es;
 
-	es = exfat_get_dentry_set(sb, p_dir, entry, ES_ALL_ENTRIES, &ep);
+	es = exfat_get_dentry_set(sb, p_dir, entry, ES_ALL_ENTRIES);
 	if (!es)
 		return;
 
-	if (es->num_entries < 3)
-		goto free_es;
-
-	ep += 2;
-
 	/*
 	 * First entry  : file entry
 	 * Second entry : stream-extension entry
 	 * Third entry  : first file-name entry
 	 * So, the index of first file-name dentry should start from 2.
 	 */
-	for (i = 2; i < es->num_entries; i++, ep++) {
+	for (i = 2; i < es->num_entries; i++) {
+		struct exfat_dentry *ep = exfat_get_dentry_cached(es, i);
+
 		/* end of name entry */
 		if (exfat_get_entry_type(ep) != TYPE_EXTEND)
-			goto free_es;
+			break;
 
 		exfat_extract_uni_name(ep, uniname);
 		uniname += EXFAT_FILE_NAME_LEN;
 	}
 
-free_es:
-	kfree(es);
+	exfat_free_dentry_set(es, false);
 }
 
 /* read a directory entry from the opened directory */
@@ -137,12 +132,12 @@ static int exfat_readdir(struct inode *inode, struct exfat_dir_entry *dir_entry)
 					ep->dentry.file.create_tz,
 					ep->dentry.file.create_time,
 					ep->dentry.file.create_date,
-					ep->dentry.file.create_time_ms);
+					ep->dentry.file.create_time_cs);
 			exfat_get_entry_time(sbi, &dir_entry->mtime,
 					ep->dentry.file.modify_tz,
 					ep->dentry.file.modify_time,
 					ep->dentry.file.modify_date,
-					ep->dentry.file.modify_time_ms);
+					ep->dentry.file.modify_time_cs);
 			exfat_get_entry_time(sbi, &dir_entry->atime,
 					ep->dentry.file.access_tz,
 					ep->dentry.file.access_time,
@@ -461,12 +456,12 @@ int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
 			&ep->dentry.file.create_tz,
 			&ep->dentry.file.create_time,
 			&ep->dentry.file.create_date,
-			&ep->dentry.file.create_time_ms);
+			&ep->dentry.file.create_time_cs);
 	exfat_set_entry_time(sbi, &ts,
 			&ep->dentry.file.modify_tz,
 			&ep->dentry.file.modify_time,
 			&ep->dentry.file.modify_date,
-			&ep->dentry.file.modify_time_ms);
+			&ep->dentry.file.modify_time_cs);
 	exfat_set_entry_time(sbi, &ts,
 			&ep->dentry.file.access_tz,
 			&ep->dentry.file.access_time,
@@ -496,7 +491,7 @@ int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
 	int ret = 0;
 	int i, num_entries;
 	sector_t sector;
-	unsigned short chksum;
+	u16 chksum;
 	struct exfat_dentry *ep, *fep;
 	struct buffer_head *fbh, *bh;
 
@@ -505,7 +500,7 @@ int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
 		return -EIO;
 
 	num_entries = fep->dentry.file.num_ext + 1;
-	chksum = exfat_calc_chksum_2byte(fep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
+	chksum = exfat_calc_chksum16(fep, DENTRY_SIZE, 0, CS_DIR_ENTRY);
 
 	for (i = 1; i < num_entries; i++) {
 		ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, NULL);
@@ -513,7 +508,7 @@ int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
 			ret = -EIO;
 			goto release_fbh;
 		}
-		chksum = exfat_calc_chksum_2byte(ep, DENTRY_SIZE, chksum,
+		chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
 				CS_DEFAULT);
 		brelse(bh);
 	}
@@ -590,62 +585,33 @@ int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
 	return 0;
 }
 
-int exfat_update_dir_chksum_with_entry_set(struct super_block *sb,
-		struct exfat_entry_set_cache *es, int sync)
+void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
 {
-	struct exfat_sb_info *sbi = EXFAT_SB(sb);
-	struct buffer_head *bh;
-	sector_t sec = es->sector;
-	unsigned int off = es->offset;
-	int chksum_type = CS_DIR_ENTRY, i, num_entries = es->num_entries;
-	unsigned int buf_off = (off - es->offset);
-	unsigned int remaining_byte_in_sector, copy_entries, clu;
+	int chksum_type = CS_DIR_ENTRY, i;
 	unsigned short chksum = 0;
+	struct exfat_dentry *ep;
 
-	for (i = 0; i < num_entries; i++) {
-		chksum = exfat_calc_chksum_2byte(&es->entries[i], DENTRY_SIZE,
-			chksum, chksum_type);
+	for (i = 0; i < es->num_entries; i++) {
+		ep = exfat_get_dentry_cached(es, i);
+		chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
+					     chksum_type);
 		chksum_type = CS_DEFAULT;
 	}
+	ep = exfat_get_dentry_cached(es, 0);
+	ep->dentry.file.checksum = cpu_to_le16(chksum);
+	es->modified = true;
+}
 
-	es->entries[0].dentry.file.checksum = cpu_to_le16(chksum);
+void exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync)
+{
+	int i;
 
-	while (num_entries) {
-		/* write per sector base */
-		remaining_byte_in_sector = (1 << sb->s_blocksize_bits) - off;
-		copy_entries = min_t(int,
-			EXFAT_B_TO_DEN(remaining_byte_in_sector),
-			num_entries);
-		bh = sb_bread(sb, sec);
-		if (!bh)
-			goto err_out;
-		memcpy(bh->b_data + off,
-			(unsigned char *)&es->entries[0] + buf_off,
-			EXFAT_DEN_TO_B(copy_entries));
-		exfat_update_bh(sb, bh, sync);
-		brelse(bh);
-		num_entries -= copy_entries;
-
-		if (num_entries) {
-			/* get next sector */
-			if (exfat_is_last_sector_in_cluster(sbi, sec)) {
-				clu = exfat_sector_to_cluster(sbi, sec);
-				if (es->alloc_flag == ALLOC_NO_FAT_CHAIN)
-					clu++;
-				else if (exfat_get_next_cluster(sb, &clu))
-					goto err_out;
-				sec = exfat_cluster_to_sector(sbi, clu);
-			} else {
-				sec++;
-			}
-			off = 0;
-			buf_off += EXFAT_DEN_TO_B(copy_entries);
-		}
+	for (i = 0; i < es->num_bh; i++) {
+		if (es->modified)
+			exfat_update_bh(es->sb, es->bh[i], sync);
+		brelse(es->bh[i]);
 	}
-
-	return 0;
-err_out:
-	return -EIO;
+	kfree(es);
 }
 
 static int exfat_walk_fat_chain(struct super_block *sb,
@@ -720,9 +686,8 @@ static int exfat_dir_readahead(struct super_block *sb, sector_t sec)
 		return 0;
 
 	if (sec < sbi->data_start_sector) {
-		exfat_msg(sb, KERN_ERR,
-			"requested sector is invalid(sect:%llu, root:%llu)",
-			(unsigned long long)sec, sbi->data_start_sector);
+		exfat_err(sb, "requested sector is invalid(sect:%llu, root:%llu)",
+			  (unsigned long long)sec, sbi->data_start_sector);
 		return -EIO;
 	}
 
@@ -750,7 +715,7 @@ struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 	sector_t sec;
 
 	if (p_dir->dir == DIR_DELETED) {
-		exfat_msg(sb, KERN_ERR, "abnormal access to deleted dentry\n");
+		exfat_err(sb, "abnormal access to deleted dentry");
 		return NULL;
 	}
 
@@ -821,39 +786,45 @@ static bool exfat_validate_entry(unsigned int type,
 	}
 }
 
+struct exfat_dentry *exfat_get_dentry_cached(
+	struct exfat_entry_set_cache *es, int num)
+{
+	int off = es->start_off + num * DENTRY_SIZE;
+	struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
+	char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
+
+	return (struct exfat_dentry *)p;
+}
+
 /*
  * Returns a set of dentries for a file or dir.
  *
- * Note that this is a copy (dump) of dentries so that user should
- * call write_entry_set() to apply changes made in this entry set
- * to the real device.
+ * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
+ * User should call exfat_get_dentry_set() after setting 'modified' to apply
+ * changes made in this entry set to the real device.
  *
  * in:
  *   sb+p_dir+entry: indicates a file/dir
  *   type:  specifies how many dentries should be included.
- * out:
- *   file_ep: will point the first dentry(= file dentry) on success
  * return:
  *   pointer of entry set on success,
  *   NULL on failure.
  */
 struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
-		struct exfat_chain *p_dir, int entry, unsigned int type,
-		struct exfat_dentry **file_ep)
+		struct exfat_chain *p_dir, int entry, unsigned int type)
 {
-	int ret;
+	int ret, i, num_bh;
 	unsigned int off, byte_offset, clu = 0;
-	unsigned int entry_type;
 	sector_t sec;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 	struct exfat_entry_set_cache *es;
-	struct exfat_dentry *ep, *pos;
-	unsigned char num_entries;
+	struct exfat_dentry *ep;
+	int num_entries;
 	enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
 	struct buffer_head *bh;
 
 	if (p_dir->dir == DIR_DELETED) {
-		exfat_msg(sb, KERN_ERR, "access to deleted dentry\n");
+		exfat_err(sb, "access to deleted dentry");
 		return NULL;
 	}
 
@@ -862,11 +833,18 @@ struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
 	if (ret)
 		return NULL;
 
+	es = kzalloc(sizeof(*es), GFP_KERNEL);
+	if (!es)
+		return NULL;
+	es->sb = sb;
+	es->modified = false;
+
 	/* byte offset in cluster */
 	byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
 
 	/* byte offset in sector */
 	off = EXFAT_BLK_OFFSET(byte_offset, sb);
+	es->start_off = off;
 
 	/* sector offset in cluster */
 	sec = EXFAT_B_TO_BLK(byte_offset, sb);
@@ -874,72 +852,46 @@ struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
 
 	bh = sb_bread(sb, sec);
 	if (!bh)
-		return NULL;
-
-	ep = (struct exfat_dentry *)(bh->b_data + off);
-	entry_type = exfat_get_entry_type(ep);
+		goto free_es;
+	es->bh[es->num_bh++] = bh;
 
-	if (entry_type != TYPE_FILE && entry_type != TYPE_DIR)
-		goto release_bh;
+	ep = exfat_get_dentry_cached(es, 0);
+	if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
+		goto free_es;
 
 	num_entries = type == ES_ALL_ENTRIES ?
 		ep->dentry.file.num_ext + 1 : type;
-	es = kmalloc(struct_size(es, entries, num_entries), GFP_KERNEL);
-	if (!es)
-		goto release_bh;
-
 	es->num_entries = num_entries;
-	es->sector = sec;
-	es->offset = off;
-	es->alloc_flag = p_dir->flags;
-
-	pos = &es->entries[0];
-
-	while (num_entries) {
-		if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
-			goto free_es;
-
-		/* copy dentry */
-		memcpy(pos, ep, sizeof(struct exfat_dentry));
-
-		if (--num_entries == 0)
-			break;
-
-		if (((off + DENTRY_SIZE) & (sb->s_blocksize - 1)) <
-		    (off & (sb->s_blocksize - 1))) {
-			/* get the next sector */
-			if (exfat_is_last_sector_in_cluster(sbi, sec)) {
-				if (es->alloc_flag == ALLOC_NO_FAT_CHAIN)
-					clu++;
-				else if (exfat_get_next_cluster(sb, &clu))
-					goto free_es;
-				sec = exfat_cluster_to_sector(sbi, clu);
-			} else {
-				sec++;
-			}
 
-			brelse(bh);
-			bh = sb_bread(sb, sec);
-			if (!bh)
+	num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
+	for (i = 1; i < num_bh; i++) {
+		/* get the next sector */
+		if (exfat_is_last_sector_in_cluster(sbi, sec)) {
+			if (p_dir->flags == ALLOC_NO_FAT_CHAIN)
+				clu++;
+			else if (exfat_get_next_cluster(sb, &clu))
 				goto free_es;
-			off = 0;
-			ep = (struct exfat_dentry *)bh->b_data;
+			sec = exfat_cluster_to_sector(sbi, clu);
 		} else {
-			ep++;
-			off += DENTRY_SIZE;
+			sec++;
 		}
-		pos++;
+
+		bh = sb_bread(sb, sec);
+		if (!bh)
+			goto free_es;
+		es->bh[es->num_bh++] = bh;
 	}
 
-	if (file_ep)
-		*file_ep = &es->entries[0];
-	brelse(bh);
+	/* validiate cached dentries */
+	for (i = 1; i < num_entries; i++) {
+		ep = exfat_get_dentry_cached(es, i);
+		if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
+			goto free_es;
+	}
 	return es;
 
 free_es:
-	kfree(es);
-release_bh:
-	brelse(bh);
+	exfat_free_dentry_set(es, false);
 	return NULL;
 }
 
@@ -1048,7 +1000,7 @@ rewind:
 			}
 
 			if (entry_type == TYPE_STREAM) {
-				unsigned short name_hash;
+				u16 name_hash;
 
 				if (step != DIRENT_STEP_STRM) {
 					step = DIRENT_STEP_FILE;
diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index d67fb8a6f770..595f3117f492 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -71,10 +71,8 @@ enum {
 #define MAX_NAME_LENGTH		255 /* max len of file name excluding NULL */
 #define MAX_VFSNAME_BUF_SIZE	((MAX_NAME_LENGTH + 1) * MAX_CHARSET_SIZE)
 
-#define FAT_CACHE_SIZE		128
-#define FAT_CACHE_HASH_SIZE	64
-#define BUF_CACHE_SIZE		256
-#define BUF_CACHE_HASH_SIZE	64
+/* Enough size to hold 256 dentry (even 512 Byte sector) */
+#define DIR_CACHE_SIZE		(256*sizeof(struct exfat_dentry)/512+1)
 
 #define EXFAT_HINT_NONE		-1
 #define EXFAT_MIN_SUBDIR	2
@@ -139,7 +137,7 @@ struct exfat_dentry_namebuf {
 struct exfat_uni_name {
 	/* +3 for null and for converting */
 	unsigned short name[MAX_NAME_LENGTH + 3];
-	unsigned short name_hash;
+	u16 name_hash;
 	unsigned char name_len;
 };
 
@@ -170,14 +168,12 @@ struct exfat_hint {
 };
 
 struct exfat_entry_set_cache {
-	/* sector number that contains file_entry */
-	sector_t sector;
-	/* byte offset in the sector */
-	unsigned int offset;
-	/* flag in stream entry. 01 for cluster chain, 03 for contig. */
-	int alloc_flag;
+	struct super_block *sb;
+	bool modified;
+	unsigned int start_off;
+	int num_bh;
+	struct buffer_head *bh[DIR_CACHE_SIZE];
 	unsigned int num_entries;
-	struct exfat_dentry entries[];
 };
 
 struct exfat_dir_entry {
@@ -231,7 +227,7 @@ struct exfat_sb_info {
 	unsigned int root_dir; /* root dir cluster */
 	unsigned int dentries_per_clu; /* num of dentries per cluster */
 	unsigned int vol_flag; /* volume dirty flag */
-	struct buffer_head *pbr_bh; /* buffer_head of PBR sector */
+	struct buffer_head *boot_bh; /* buffer_head of BOOT sector */
 
 	unsigned int map_clu; /* allocation bitmap start cluster */
 	unsigned int map_sectors; /* num of allocation bitmap sectors */
@@ -451,8 +447,7 @@ int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
 		int entry, int order, int num_entries);
 int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
 		int entry);
-int exfat_update_dir_chksum_with_entry_set(struct super_block *sb,
-		struct exfat_entry_set_cache *es, int sync);
+void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es);
 int exfat_calc_num_entries(struct exfat_uni_name *p_uniname);
 int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 		struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
@@ -463,9 +458,11 @@ int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
 struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
 		struct exfat_chain *p_dir, int entry, struct buffer_head **bh,
 		sector_t *sector);
+struct exfat_dentry *exfat_get_dentry_cached(struct exfat_entry_set_cache *es,
+		int num);
 struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
-		struct exfat_chain *p_dir, int entry, unsigned int type,
-		struct exfat_dentry **file_ep);
+		struct exfat_chain *p_dir, int entry, unsigned int type);
+void exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync);
 int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir);
 
 /* inode.c */
@@ -492,8 +489,6 @@ int exfat_nls_to_utf16(struct super_block *sb,
 		struct exfat_uni_name *uniname, int *p_lossy);
 int exfat_create_upcase_table(struct super_block *sb);
 void exfat_free_upcase_table(struct exfat_sb_info *sbi);
-unsigned short exfat_high_surrogate(unicode_t u);
-unsigned short exfat_low_surrogate(unicode_t u);
 
 /* exfat/misc.c */
 void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
@@ -505,13 +500,20 @@ void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
 		fmt, ## args)
 void exfat_msg(struct super_block *sb, const char *lv, const char *fmt, ...)
 		__printf(3, 4) __cold;
+#define exfat_err(sb, fmt, ...)						\
+	exfat_msg(sb, KERN_ERR, fmt, ##__VA_ARGS__)
+#define exfat_warn(sb, fmt, ...)					\
+	exfat_msg(sb, KERN_WARNING, fmt, ##__VA_ARGS__)
+#define exfat_info(sb, fmt, ...)					\
+	exfat_msg(sb, KERN_INFO, fmt, ##__VA_ARGS__)
+
 void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
-		u8 tz, __le16 time, __le16 date, u8 time_ms);
+		u8 tz, __le16 time, __le16 date, u8 time_cs);
 void exfat_truncate_atime(struct timespec64 *ts);
 void exfat_set_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
-		u8 *tz, __le16 *time, __le16 *date, u8 *time_ms);
-unsigned short exfat_calc_chksum_2byte(void *data, int len,
-		unsigned short chksum, int type);
+		u8 *tz, __le16 *time, __le16 *date, u8 *time_cs);
+u16 exfat_calc_chksum16(void *data, int len, u16 chksum, int type);
+u32 exfat_calc_chksum32(void *data, int len, u32 chksum, int type);
 void exfat_update_bh(struct super_block *sb, struct buffer_head *bh, int sync);
 void exfat_chain_set(struct exfat_chain *ec, unsigned int dir,
 		unsigned int size, unsigned char flags);
diff --git a/fs/exfat/exfat_raw.h b/fs/exfat/exfat_raw.h
index 2a841010e649..350ce59cc324 100644
--- a/fs/exfat/exfat_raw.h
+++ b/fs/exfat/exfat_raw.h
@@ -8,12 +8,15 @@
 
 #include <linux/types.h>
 
-#define PBR_SIGNATURE		0xAA55
+#define BOOT_SIGNATURE		0xAA55
+#define EXBOOT_SIGNATURE	0xAA550000
+#define STR_EXFAT		"EXFAT   "	/* size should be 8 */
 
 #define EXFAT_MAX_FILE_LEN	255
 
 #define VOL_CLEAN		0x0000
 #define VOL_DIRTY		0x0002
+#define ERR_MEDIUM		0x0004
 
 #define EXFAT_EOF_CLUSTER	0xFFFFFFFFu
 #define EXFAT_BAD_CLUSTER	0xFFFFFFF7u
@@ -55,7 +58,7 @@
 
 /* checksum types */
 #define CS_DIR_ENTRY		0
-#define CS_PBR_SECTOR		1
+#define CS_BOOT_SECTOR		1
 #define CS_DEFAULT		2
 
 /* file attributes */
@@ -69,57 +72,35 @@
 #define ATTR_RWMASK		(ATTR_HIDDEN | ATTR_SYSTEM | ATTR_VOLUME | \
 				 ATTR_SUBDIR | ATTR_ARCHIVE)
 
-#define PBR64_JUMP_BOOT_LEN		3
-#define PBR64_OEM_NAME_LEN		8
-#define PBR64_RESERVED_LEN		53
+#define BOOTSEC_JUMP_BOOT_LEN		3
+#define BOOTSEC_FS_NAME_LEN		8
+#define BOOTSEC_OLDBPB_LEN		53
 
 #define EXFAT_FILE_NAME_LEN		15
 
-/* EXFAT BIOS parameter block (64 bytes) */
-struct bpb64 {
-	__u8 jmp_boot[PBR64_JUMP_BOOT_LEN];
-	__u8 oem_name[PBR64_OEM_NAME_LEN];
-	__u8 res_zero[PBR64_RESERVED_LEN];
-} __packed;
-
-/* EXFAT EXTEND BIOS parameter block (56 bytes) */
-struct bsx64 {
-	__le64 vol_offset;
-	__le64 vol_length;
-	__le32 fat_offset;
-	__le32 fat_length;
-	__le32 clu_offset;
-	__le32 clu_count;
-	__le32 root_cluster;
-	__le32 vol_serial;
-	__u8 fs_version[2];
-	__le16 vol_flags;
-	__u8 sect_size_bits;
-	__u8 sect_per_clus_bits;
-	__u8 num_fats;
-	__u8 phy_drv_no;
-	__u8 perc_in_use;
-	__u8 reserved2[7];
-} __packed;
-
-/* EXFAT PBR[BPB+BSX] (120 bytes) */
-struct pbr64 {
-	struct bpb64 bpb;
-	struct bsx64 bsx;
-} __packed;
-
-/* Common PBR[Partition Boot Record] (512 bytes) */
-struct pbr {
-	union {
-		__u8 raw[64];
-		struct bpb64 f64;
-	} bpb;
-	union {
-		__u8 raw[56];
-		struct bsx64 f64;
-	} bsx;
-	__u8 boot_code[390];
-	__le16 signature;
+/* EXFAT: Main and Backup Boot Sector (512 bytes) */
+struct boot_sector {
+	__u8	jmp_boot[BOOTSEC_JUMP_BOOT_LEN];
+	__u8	fs_name[BOOTSEC_FS_NAME_LEN];
+	__u8	must_be_zero[BOOTSEC_OLDBPB_LEN];
+	__le64	partition_offset;
+	__le64	vol_length;
+	__le32	fat_offset;
+	__le32	fat_length;
+	__le32	clu_offset;
+	__le32	clu_count;
+	__le32	root_cluster;
+	__le32	vol_serial;
+	__u8	fs_revision[2];
+	__le16	vol_flags;
+	__u8	sect_size_bits;
+	__u8	sect_per_clus_bits;
+	__u8	num_fats;
+	__u8	drv_sel;
+	__u8	percent_in_use;
+	__u8	reserved[7];
+	__u8	boot_code[390];
+	__le16	signature;
 } __packed;
 
 struct exfat_dentry {
@@ -136,8 +117,8 @@ struct exfat_dentry {
 			__le16 modify_date;
 			__le16 access_time;
 			__le16 access_date;
-			__u8 create_time_ms;
-			__u8 modify_time_ms;
+			__u8 create_time_cs;
+			__u8 modify_time_cs;
 			__u8 create_tz;
 			__u8 modify_tz;
 			__u8 access_tz;
diff --git a/fs/exfat/fatent.c b/fs/exfat/fatent.c
index a855b1769a96..4e5c5c9c0f2d 100644
--- a/fs/exfat/fatent.c
+++ b/fs/exfat/fatent.c
@@ -169,9 +169,8 @@ int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain)
 		return 0;
 
 	/* check cluster validation */
-	if (p_chain->dir < 2 && p_chain->dir >= sbi->num_clusters) {
-		exfat_msg(sb, KERN_ERR, "invalid start cluster (%u)",
-				p_chain->dir);
+	if (!is_valid_cluster(sbi, p_chain->dir)) {
+		exfat_err(sb, "invalid start cluster (%u)", p_chain->dir);
 		return -EIO;
 	}
 
@@ -305,8 +304,7 @@ int exfat_zeroed_cluster(struct inode *dir, unsigned int clu)
 	return 0;
 
 release_bhs:
-	exfat_msg(sb, KERN_ERR, "failed zeroed sect %llu\n",
-		(unsigned long long)blknr);
+	exfat_err(sb, "failed zeroed sect %llu\n", (unsigned long long)blknr);
 	for (i = 0; i < n; i++)
 		bforget(bhs[i]);
 	return err;
@@ -337,9 +335,8 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 	/* find new cluster */
 	if (hint_clu == EXFAT_EOF_CLUSTER) {
 		if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) {
-			exfat_msg(sb, KERN_ERR,
-				"sbi->clu_srch_ptr is invalid (%u)\n",
-				sbi->clu_srch_ptr);
+			exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)\n",
+				  sbi->clu_srch_ptr);
 			sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
 		}
 
@@ -349,8 +346,8 @@ int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
 	}
 
 	/* check cluster validation */
-	if (hint_clu < EXFAT_FIRST_CLUSTER && hint_clu >= sbi->num_clusters) {
-		exfat_msg(sb, KERN_ERR, "hint_cluster is invalid (%u)\n",
+	if (!is_valid_cluster(sbi, hint_clu)) {
+		exfat_err(sb, "hint_cluster is invalid (%u)",
 			hint_clu);
 		hint_clu = EXFAT_FIRST_CLUSTER;
 		if (p_chain->flags == ALLOC_NO_FAT_CHAIN) {
diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index c9db8eb0cfc3..fce03f318787 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -96,11 +96,9 @@ int __exfat_truncate(struct inode *inode, loff_t new_size)
 	unsigned int num_clusters_new, num_clusters_phys;
 	unsigned int last_clu = EXFAT_FREE_CLUSTER;
 	struct exfat_chain clu;
-	struct exfat_dentry *ep, *ep2;
 	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_entry_set_cache *es = NULL;
 	int evict = (ei->dir.dir == DIR_DELETED) ? 1 : 0;
 
 	/* check if the given file ID is opened */
@@ -153,28 +151,31 @@ int __exfat_truncate(struct inode *inode, loff_t new_size)
 	/* update the directory entry */
 	if (!evict) {
 		struct timespec64 ts;
+		struct exfat_dentry *ep, *ep2;
+		struct exfat_entry_set_cache *es;
 
 		es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry,
-				ES_ALL_ENTRIES, &ep);
+				ES_ALL_ENTRIES);
 		if (!es)
 			return -EIO;
-		ep2 = ep + 1;
+		ep = exfat_get_dentry_cached(es, 0);
+		ep2 = exfat_get_dentry_cached(es, 1);
 
 		ts = current_time(inode);
 		exfat_set_entry_time(sbi, &ts,
 				&ep->dentry.file.modify_tz,
 				&ep->dentry.file.modify_time,
 				&ep->dentry.file.modify_date,
-				&ep->dentry.file.modify_time_ms);
+				&ep->dentry.file.modify_time_cs);
 		ep->dentry.file.attr = cpu_to_le16(ei->attr);
 
 		/* File size should be zero if there is no cluster allocated */
 		if (ei->start_clu == EXFAT_EOF_CLUSTER) {
-			ep->dentry.stream.valid_size = 0;
-			ep->dentry.stream.size = 0;
+			ep2->dentry.stream.valid_size = 0;
+			ep2->dentry.stream.size = 0;
 		} else {
-			ep->dentry.stream.valid_size = cpu_to_le64(new_size);
-			ep->dentry.stream.size = ep->dentry.stream.valid_size;
+			ep2->dentry.stream.valid_size = cpu_to_le64(new_size);
+			ep2->dentry.stream.size = ep->dentry.stream.valid_size;
 		}
 
 		if (new_size == 0) {
@@ -185,10 +186,8 @@ int __exfat_truncate(struct inode *inode, loff_t new_size)
 			ep2->dentry.stream.start_clu = EXFAT_FREE_CLUSTER;
 		}
 
-		if (exfat_update_dir_chksum_with_entry_set(sb, es,
-		    inode_needs_sync(inode)))
-			return -EIO;
-		kfree(es);
+		exfat_update_dir_chksum_with_entry_set(es);
+		exfat_free_dentry_set(es, inode_needs_sync(inode));
 	}
 
 	/* cut off from the FAT chain */
diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c
index 785ead346543..cf9ca6c4d046 100644
--- a/fs/exfat/inode.c
+++ b/fs/exfat/inode.c
@@ -19,7 +19,6 @@
 
 static int __exfat_write_inode(struct inode *inode, int sync)
 {
-	int ret = -EIO;
 	unsigned long long on_disk_size;
 	struct exfat_dentry *ep, *ep2;
 	struct exfat_entry_set_cache *es = NULL;
@@ -43,11 +42,11 @@ static int __exfat_write_inode(struct inode *inode, int sync)
 	exfat_set_vol_flags(sb, VOL_DIRTY);
 
 	/* get the directory entry of given file or directory */
-	es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry, ES_ALL_ENTRIES,
-		&ep);
+	es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry, ES_ALL_ENTRIES);
 	if (!es)
 		return -EIO;
-	ep2 = ep + 1;
+	ep = exfat_get_dentry_cached(es, 0);
+	ep2 = exfat_get_dentry_cached(es, 1);
 
 	ep->dentry.file.attr = cpu_to_le16(exfat_make_attr(inode));
 
@@ -56,12 +55,12 @@ static int __exfat_write_inode(struct inode *inode, int sync)
 			&ep->dentry.file.create_tz,
 			&ep->dentry.file.create_time,
 			&ep->dentry.file.create_date,
-			&ep->dentry.file.create_time_ms);
+			&ep->dentry.file.create_time_cs);
 	exfat_set_entry_time(sbi, &inode->i_mtime,
 			&ep->dentry.file.modify_tz,
 			&ep->dentry.file.modify_time,
 			&ep->dentry.file.modify_date,
-			&ep->dentry.file.modify_time_ms);
+			&ep->dentry.file.modify_time_cs);
 	exfat_set_entry_time(sbi, &inode->i_atime,
 			&ep->dentry.file.access_tz,
 			&ep->dentry.file.access_time,
@@ -77,9 +76,9 @@ static int __exfat_write_inode(struct inode *inode, int sync)
 	ep2->dentry.stream.valid_size = cpu_to_le64(on_disk_size);
 	ep2->dentry.stream.size = ep2->dentry.stream.valid_size;
 
-	ret = exfat_update_dir_chksum_with_entry_set(sb, es, sync);
-	kfree(es);
-	return ret;
+	exfat_update_dir_chksum_with_entry_set(es);
+	exfat_free_dentry_set(es, sync);
+	return 0;
 }
 
 int exfat_write_inode(struct inode *inode, struct writeback_control *wbc)
@@ -110,8 +109,6 @@ static int exfat_map_cluster(struct inode *inode, unsigned int clu_offset,
 	int ret, modified = false;
 	unsigned int last_clu;
 	struct exfat_chain new_clu;
-	struct exfat_dentry *ep;
-	struct exfat_entry_set_cache *es = NULL;
 	struct super_block *sb = inode->i_sb;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 	struct exfat_inode_info *ei = EXFAT_I(inode);
@@ -222,34 +219,28 @@ static int exfat_map_cluster(struct inode *inode, unsigned int clu_offset,
 		num_clusters += num_to_be_allocated;
 		*clu = new_clu.dir;
 
-		if (ei->dir.dir != DIR_DELETED) {
+		if (ei->dir.dir != DIR_DELETED && modified) {
+			struct exfat_dentry *ep;
+			struct exfat_entry_set_cache *es;
+
 			es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry,
-				ES_ALL_ENTRIES, &ep);
+				ES_ALL_ENTRIES);
 			if (!es)
 				return -EIO;
 			/* get stream entry */
-			ep++;
+			ep = exfat_get_dentry_cached(es, 1);
 
 			/* update directory entry */
-			if (modified) {
-				if (ep->dentry.stream.flags != ei->flags)
-					ep->dentry.stream.flags = ei->flags;
-
-				if (le32_to_cpu(ep->dentry.stream.start_clu) !=
-						ei->start_clu)
-					ep->dentry.stream.start_clu =
-						cpu_to_le32(ei->start_clu);
-
-				ep->dentry.stream.valid_size =
-					cpu_to_le64(i_size_read(inode));
-				ep->dentry.stream.size =
-					ep->dentry.stream.valid_size;
-			}
-
-			if (exfat_update_dir_chksum_with_entry_set(sb, es,
-			    inode_needs_sync(inode)))
-				return -EIO;
-			kfree(es);
+			ep->dentry.stream.flags = ei->flags;
+			ep->dentry.stream.start_clu =
+				cpu_to_le32(ei->start_clu);
+			ep->dentry.stream.valid_size =
+				cpu_to_le64(i_size_read(inode));
+			ep->dentry.stream.size =
+				ep->dentry.stream.valid_size;
+
+			exfat_update_dir_chksum_with_entry_set(es);
+			exfat_free_dentry_set(es, inode_needs_sync(inode));
 
 		} /* end of if != DIR_DELETED */
 
diff --git a/fs/exfat/misc.c b/fs/exfat/misc.c
index ebd2cbe3cbc1..17d41f3d3709 100644
--- a/fs/exfat/misc.c
+++ b/fs/exfat/misc.c
@@ -32,7 +32,7 @@ void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
 		va_start(args, fmt);
 		vaf.fmt = fmt;
 		vaf.va = &args;
-		exfat_msg(sb, KERN_ERR, "error, %pV\n", &vaf);
+		exfat_err(sb, "error, %pV", &vaf);
 		va_end(args);
 	}
 
@@ -41,7 +41,7 @@ void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
 			sb->s_id);
 	} else if (opts->errors == EXFAT_ERRORS_RO && !sb_rdonly(sb)) {
 		sb->s_flags |= SB_RDONLY;
-		exfat_msg(sb, KERN_ERR, "Filesystem has been set read-only");
+		exfat_err(sb, "Filesystem has been set read-only");
 	}
 }
 
@@ -75,7 +75,7 @@ static void exfat_adjust_tz(struct timespec64 *ts, u8 tz_off)
 
 /* Convert a EXFAT time/date pair to a UNIX date (seconds since 1 1 70). */
 void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
-		u8 tz, __le16 time, __le16 date, u8 time_ms)
+		u8 tz, __le16 time, __le16 date, u8 time_cs)
 {
 	u16 t = le16_to_cpu(time);
 	u16 d = le16_to_cpu(date);
@@ -84,10 +84,10 @@ void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
 			      t >> 11, (t >> 5) & 0x003F, (t & 0x001F) << 1);
 
 
-	/* time_ms field represent 0 ~ 199(1990 ms) */
-	if (time_ms) {
-		ts->tv_sec += time_ms / 100;
-		ts->tv_nsec = (time_ms % 100) * 10 * NSEC_PER_MSEC;
+	/* time_cs field represent 0 ~ 199cs(1990 ms) */
+	if (time_cs) {
+		ts->tv_sec += time_cs / 100;
+		ts->tv_nsec = (time_cs % 100) * 10 * NSEC_PER_MSEC;
 	} else
 		ts->tv_nsec = 0;
 
@@ -101,7 +101,7 @@ void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
 
 /* Convert linear UNIX date to a EXFAT time/date pair. */
 void exfat_set_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
-		u8 *tz, __le16 *time, __le16 *date, u8 *time_ms)
+		u8 *tz, __le16 *time, __le16 *date, u8 *time_cs)
 {
 	struct tm tm;
 	u16 t, d;
@@ -113,9 +113,9 @@ void exfat_set_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
 	*time = cpu_to_le16(t);
 	*date = cpu_to_le16(d);
 
-	/* time_ms field represent 0 ~ 199(1990 ms) */
-	if (time_ms)
-		*time_ms = (tm.tm_sec & 1) * 100 +
+	/* time_cs field represent 0 ~ 199cs(1990 ms) */
+	if (time_cs)
+		*time_cs = (tm.tm_sec & 1) * 100 +
 			ts->tv_nsec / (10 * NSEC_PER_MSEC);
 
 	/*
@@ -136,17 +136,29 @@ void exfat_truncate_atime(struct timespec64 *ts)
 	ts->tv_nsec = 0;
 }
 
-unsigned short exfat_calc_chksum_2byte(void *data, int len,
-		unsigned short chksum, int type)
+u16 exfat_calc_chksum16(void *data, int len, u16 chksum, int type)
 {
 	int i;
-	unsigned char *c = (unsigned char *)data;
+	u8 *c = (u8 *)data;
 
 	for (i = 0; i < len; i++, c++) {
-		if (((i == 2) || (i == 3)) && (type == CS_DIR_ENTRY))
+		if (unlikely(type == CS_DIR_ENTRY && (i == 2 || i == 3)))
 			continue;
-		chksum = (((chksum & 1) << 15) | ((chksum & 0xFFFE) >> 1)) +
-			(unsigned short)*c;
+		chksum = ((chksum << 15) | (chksum >> 1)) + *c;
+	}
+	return chksum;
+}
+
+u32 exfat_calc_chksum32(void *data, int len, u32 chksum, int type)
+{
+	int i;
+	u8 *c = (u8 *)data;
+
+	for (i = 0; i < len; i++, c++) {
+		if (unlikely(type == CS_BOOT_SECTOR &&
+			     (i == 106 || i == 107 || i == 112)))
+			continue;
+		chksum = ((chksum << 31) | (chksum >> 1)) + *c;
 	}
 	return chksum;
 }
diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index a2659a8a68a1..5b0f35329d63 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -147,16 +147,10 @@ static int exfat_utf8_d_hash(const struct dentry *dentry, struct qstr *qstr)
 			return charlen;
 
 		/*
-		 * Convert to UTF-16: code points above U+FFFF are encoded as
-		 * surrogate pairs.
 		 * exfat_toupper() works only for code points up to the U+FFFF.
 		 */
-		if (u > 0xFFFF) {
-			hash = partial_name_hash(exfat_high_surrogate(u), hash);
-			hash = partial_name_hash(exfat_low_surrogate(u), hash);
-		} else {
-			hash = partial_name_hash(exfat_toupper(sb, u), hash);
-		}
+		hash = partial_name_hash(u <= 0xFFFF ? exfat_toupper(sb, u) : u,
+					 hash);
 	}
 
 	qstr->hash = end_name_hash(hash);
@@ -185,14 +179,9 @@ static int exfat_utf8_d_cmp(const struct dentry *dentry, unsigned int len,
 		if (u_a <= 0xFFFF && u_b <= 0xFFFF) {
 			if (exfat_toupper(sb, u_a) != exfat_toupper(sb, u_b))
 				return 1;
-		} else if (u_a > 0xFFFF && u_b > 0xFFFF) {
-			if (exfat_low_surrogate(u_a) !=
-					exfat_low_surrogate(u_b) ||
-			    exfat_high_surrogate(u_a) !=
-					exfat_high_surrogate(u_b))
-				return 1;
 		} else {
-			return 1;
+			if (u_a != u_b)
+				return 1;
 		}
 	}
 
@@ -611,8 +600,6 @@ static int exfat_find(struct inode *dir, struct qstr *qname,
 	int ret, dentry, num_entries, count;
 	struct exfat_chain cdir;
 	struct exfat_uni_name uni_name;
-	struct exfat_dentry *ep, *ep2;
-	struct exfat_entry_set_cache *es = NULL;
 	struct super_block *sb = dir->i_sb;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 	struct exfat_inode_info *ei = EXFAT_I(dir);
@@ -671,10 +658,14 @@ static int exfat_find(struct inode *dir, struct qstr *qname,
 
 		info->num_subdirs = count;
 	} else {
-		es = exfat_get_dentry_set(sb, &cdir, dentry, ES_2_ENTRIES, &ep);
+		struct exfat_dentry *ep, *ep2;
+		struct exfat_entry_set_cache *es;
+
+		es = exfat_get_dentry_set(sb, &cdir, dentry, ES_2_ENTRIES);
 		if (!es)
 			return -EIO;
-		ep2 = ep + 1;
+		ep = exfat_get_dentry_cached(es, 0);
+		ep2 = exfat_get_dentry_cached(es, 1);
 
 		info->type = exfat_get_entry_type(ep);
 		info->attr = le16_to_cpu(ep->dentry.file.attr);
@@ -692,7 +683,7 @@ static int exfat_find(struct inode *dir, struct qstr *qname,
 			exfat_fs_error(sb,
 				"non-zero size file starts with zero cluster (size : %llu, p_dir : %u, entry : 0x%08x)",
 				i_size_read(dir), ei->dir.dir, ei->entry);
-			kfree(es);
+			exfat_free_dentry_set(es, false);
 			return -EIO;
 		}
 
@@ -700,18 +691,18 @@ static int exfat_find(struct inode *dir, struct qstr *qname,
 				ep->dentry.file.create_tz,
 				ep->dentry.file.create_time,
 				ep->dentry.file.create_date,
-				ep->dentry.file.create_time_ms);
+				ep->dentry.file.create_time_cs);
 		exfat_get_entry_time(sbi, &info->mtime,
 				ep->dentry.file.modify_tz,
 				ep->dentry.file.modify_time,
 				ep->dentry.file.modify_date,
-				ep->dentry.file.modify_time_ms);
+				ep->dentry.file.modify_time_cs);
 		exfat_get_entry_time(sbi, &info->atime,
 				ep->dentry.file.access_tz,
 				ep->dentry.file.access_time,
 				ep->dentry.file.access_date,
 				0);
-		kfree(es);
+		exfat_free_dentry_set(es, false);
 
 		if (info->type == TYPE_DIR) {
 			exfat_chain_set(&cdir, info->start_clu,
@@ -778,8 +769,8 @@ static struct dentry *exfat_lookup(struct inode *dir, struct dentry *dentry,
 		if (d_unhashed(alias)) {
 			WARN_ON(alias->d_name.hash_len !=
 				dentry->d_name.hash_len);
-			exfat_msg(sb, KERN_INFO,
-				"rehashed a dentry(%p) in read lookup", alias);
+			exfat_info(sb, "rehashed a dentry(%p) in read lookup",
+				   alias);
 			d_drop(dentry);
 			d_rehash(alias);
 		} else if (!S_ISDIR(i_mode)) {
@@ -824,7 +815,7 @@ static int exfat_unlink(struct inode *dir, struct dentry *dentry)
 	exfat_chain_dup(&cdir, &ei->dir);
 	entry = ei->entry;
 	if (ei->dir.dir == DIR_DELETED) {
-		exfat_msg(sb, KERN_ERR, "abnormal access to deleted dentry");
+		exfat_err(sb, "abnormal access to deleted dentry");
 		err = -ENOENT;
 		goto unlock;
 	}
@@ -979,7 +970,7 @@ static int exfat_rmdir(struct inode *dir, struct dentry *dentry)
 	entry = ei->entry;
 
 	if (ei->dir.dir == DIR_DELETED) {
-		exfat_msg(sb, KERN_ERR, "abnormal access to deleted dentry");
+		exfat_err(sb, "abnormal access to deleted dentry");
 		err = -ENOENT;
 		goto unlock;
 	}
@@ -991,9 +982,8 @@ static int exfat_rmdir(struct inode *dir, struct dentry *dentry)
 	err = exfat_check_dir_empty(sb, &clu_to_free);
 	if (err) {
 		if (err == -EIO)
-			exfat_msg(sb, KERN_ERR,
-				"failed to exfat_check_dir_empty : err(%d)",
-				err);
+			exfat_err(sb, "failed to exfat_check_dir_empty : err(%d)",
+				  err);
 		goto unlock;
 	}
 
@@ -1014,9 +1004,7 @@ static int exfat_rmdir(struct inode *dir, struct dentry *dentry)
 
 	err = exfat_remove_entries(dir, &cdir, entry, 0, num_entries);
 	if (err) {
-		exfat_msg(sb, KERN_ERR,
-				"failed to exfat_remove_entries : err(%d)",
-				err);
+		exfat_err(sb, "failed to exfat_remove_entries : err(%d)", err);
 		goto unlock;
 	}
 	ei->dir.dir = DIR_DELETED;
@@ -1245,8 +1233,7 @@ static int __exfat_rename(struct inode *old_parent_inode,
 		return -EINVAL;
 
 	if (ei->dir.dir == DIR_DELETED) {
-		exfat_msg(sb, KERN_ERR,
-				"abnormal access to deleted source dentry");
+		exfat_err(sb, "abnormal access to deleted source dentry");
 		return -ENOENT;
 	}
 
@@ -1268,8 +1255,7 @@ static int __exfat_rename(struct inode *old_parent_inode,
 		new_ei = EXFAT_I(new_inode);
 
 		if (new_ei->dir.dir == DIR_DELETED) {
-			exfat_msg(sb, KERN_ERR,
-				"abnormal access to deleted target dentry");
+			exfat_err(sb, "abnormal access to deleted target dentry");
 			goto out;
 		}
 
@@ -1431,8 +1417,7 @@ static int exfat_rename(struct inode *old_dir, struct dentry *old_dentry,
 			if (S_ISDIR(new_inode->i_mode))
 				drop_nlink(new_inode);
 		} else {
-			exfat_msg(sb, KERN_WARNING,
-					"abnormal access to an inode dropped");
+			exfat_warn(sb, "abnormal access to an inode dropped");
 			WARN_ON(new_inode->i_nlink == 0);
 		}
 		new_inode->i_ctime = EXFAT_I(new_inode)->i_crtime =
diff --git a/fs/exfat/nls.c b/fs/exfat/nls.c
index 6d1c3ae130ff..57b5a7a4d1f7 100644
--- a/fs/exfat/nls.c
+++ b/fs/exfat/nls.c
@@ -503,21 +503,17 @@ static int exfat_utf8_to_utf16(struct super_block *sb,
 	unilen = utf8s_to_utf16s(p_cstring, len, UTF16_HOST_ENDIAN,
 			(wchar_t *)uniname, MAX_NAME_LENGTH + 2);
 	if (unilen < 0) {
-		exfat_msg(sb, KERN_ERR,
-			"failed to %s (err : %d) nls len : %d",
-			__func__, unilen, len);
+		exfat_err(sb, "failed to %s (err : %d) nls len : %d",
+			  __func__, unilen, len);
 		return unilen;
 	}
 
 	if (unilen > MAX_NAME_LENGTH) {
-		exfat_msg(sb, KERN_ERR,
-			"failed to %s (estr:ENAMETOOLONG) nls len : %d, unilen : %d > %d",
-			__func__, len, unilen, MAX_NAME_LENGTH);
+		exfat_err(sb, "failed to %s (estr:ENAMETOOLONG) nls len : %d, unilen : %d > %d",
+			  __func__, len, unilen, MAX_NAME_LENGTH);
 		return -ENAMETOOLONG;
 	}
 
-	p_uniname->name_len = unilen & 0xFF;
-
 	for (i = 0; i < unilen; i++) {
 		if (*uniname < 0x0020 ||
 		    exfat_wstrchr(bad_uni_chars, *uniname))
@@ -529,7 +525,7 @@ static int exfat_utf8_to_utf16(struct super_block *sb,
 
 	*uniname = '\0';
 	p_uniname->name_len = unilen;
-	p_uniname->name_hash = exfat_calc_chksum_2byte(upname, unilen << 1, 0,
+	p_uniname->name_hash = exfat_calc_chksum16(upname, unilen << 1, 0,
 			CS_DEFAULT);
 
 	if (p_lossy)
@@ -537,22 +533,9 @@ static int exfat_utf8_to_utf16(struct super_block *sb,
 	return unilen;
 }
 
-#define PLANE_SIZE	0x00010000
 #define SURROGATE_MASK	0xfffff800
 #define SURROGATE_PAIR	0x0000d800
 #define SURROGATE_LOW	0x00000400
-#define SURROGATE_BITS	0x000003ff
-
-unsigned short exfat_high_surrogate(unicode_t u)
-{
-	return ((u - PLANE_SIZE) >> 10) + SURROGATE_PAIR;
-}
-
-unsigned short exfat_low_surrogate(unicode_t u)
-{
-	return ((u - PLANE_SIZE) & SURROGATE_BITS) | SURROGATE_PAIR |
-		SURROGATE_LOW;
-}
 
 static int __exfat_utf16_to_nls(struct super_block *sb,
 		struct exfat_uni_name *p_uniname, unsigned char *p_cstring,
@@ -638,7 +621,7 @@ static int exfat_nls_to_ucs2(struct super_block *sb,
 
 	*uniname = '\0';
 	p_uniname->name_len = unilen;
-	p_uniname->name_hash = exfat_calc_chksum_2byte(upname, unilen << 1, 0,
+	p_uniname->name_hash = exfat_calc_chksum16(upname, unilen << 1, 0,
 			CS_DEFAULT);
 
 	if (p_lossy)
@@ -670,7 +653,8 @@ static int exfat_load_upcase_table(struct super_block *sb,
 {
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 	unsigned int sect_size = sb->s_blocksize;
-	unsigned int i, index = 0, checksum = 0;
+	unsigned int i, index = 0;
+	u32 chksum = 0;
 	int ret;
 	unsigned char skip = false;
 	unsigned short *upcase_table;
@@ -687,9 +671,8 @@ static int exfat_load_upcase_table(struct super_block *sb,
 
 		bh = sb_bread(sb, sector);
 		if (!bh) {
-			exfat_msg(sb, KERN_ERR,
-				"failed to read sector(0x%llx)\n",
-				(unsigned long long)sector);
+			exfat_err(sb, "failed to read sector(0x%llx)\n",
+				  (unsigned long long)sector);
 			ret = -EIO;
 			goto free_table;
 		}
@@ -697,13 +680,6 @@ static int exfat_load_upcase_table(struct super_block *sb,
 		for (i = 0; i < sect_size && index <= 0xFFFF; i += 2) {
 			unsigned short uni = get_unaligned_le16(bh->b_data + i);
 
-			checksum = ((checksum & 1) ? 0x80000000 : 0) +
-				(checksum >> 1) +
-				*(((unsigned char *)bh->b_data) + i);
-			checksum = ((checksum & 1) ? 0x80000000 : 0) +
-				(checksum >> 1) +
-				*(((unsigned char *)bh->b_data) + (i + 1));
-
 			if (skip) {
 				index += uni;
 				skip = false;
@@ -716,15 +692,15 @@ static int exfat_load_upcase_table(struct super_block *sb,
 				index++;
 			}
 		}
+		chksum = exfat_calc_chksum32(bh->b_data, i, chksum, CS_DEFAULT);
 		brelse(bh);
 	}
 
-	if (index >= 0xFFFF && utbl_checksum == checksum)
+	if (index >= 0xFFFF && utbl_checksum == chksum)
 		return 0;
 
-	exfat_msg(sb, KERN_ERR,
-			"failed to load upcase table (idx : 0x%08x, chksum : 0x%08x, utbl_chksum : 0x%08x)\n",
-			index, checksum, utbl_checksum);
+	exfat_err(sb, "failed to load upcase table (idx : 0x%08x, chksum : 0x%08x, utbl_chksum : 0x%08x)",
+		  index, chksum, utbl_checksum);
 	ret = -EINVAL;
 free_table:
 	exfat_free_upcase_table(sbi);
diff --git a/fs/exfat/super.c b/fs/exfat/super.c
index a846ff555656..e650e65536f8 100644
--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -49,7 +49,7 @@ static void exfat_put_super(struct super_block *sb)
 		sync_blockdev(sb->s_bdev);
 	exfat_set_vol_flags(sb, VOL_CLEAN);
 	exfat_free_bitmap(sbi);
-	brelse(sbi->pbr_bh);
+	brelse(sbi->boot_bh);
 	mutex_unlock(&sbi->s_lock);
 
 	call_rcu(&sbi->rcu, exfat_delayed_free);
@@ -101,8 +101,8 @@ static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf)
 int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)
 {
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
-	struct pbr64 *bpb = (struct pbr64 *)sbi->pbr_bh->b_data;
-	bool sync = 0;
+	struct boot_sector *p_boot = (struct boot_sector *)sbi->boot_bh->b_data;
+	bool sync;
 
 	/* flags are not changed */
 	if (sbi->vol_flag == new_flag)
@@ -116,18 +116,18 @@ int exfat_set_vol_flags(struct super_block *sb, unsigned short new_flag)
 	if (sb_rdonly(sb))
 		return 0;
 
-	bpb->bsx.vol_flags = cpu_to_le16(new_flag);
+	p_boot->vol_flags = cpu_to_le16(new_flag);
 
-	if (new_flag == VOL_DIRTY && !buffer_dirty(sbi->pbr_bh))
+	if (new_flag == VOL_DIRTY && !buffer_dirty(sbi->boot_bh))
 		sync = true;
 	else
 		sync = false;
 
-	set_buffer_uptodate(sbi->pbr_bh);
-	mark_buffer_dirty(sbi->pbr_bh);
+	set_buffer_uptodate(sbi->boot_bh);
+	mark_buffer_dirty(sbi->boot_bh);
 
 	if (sync)
-		sync_dirty_buffer(sbi->pbr_bh);
+		sync_dirty_buffer(sbi->boot_bh);
 	return 0;
 }
 
@@ -273,9 +273,8 @@ static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
 		break;
 	case Opt_charset:
 		exfat_free_iocharset(sbi);
-		opts->iocharset = kstrdup(param->string, GFP_KERNEL);
-		if (!opts->iocharset)
-			return -ENOMEM;
+		opts->iocharset = param->string;
+		param->string = NULL;
 		break;
 	case Opt_errors:
 		opts->errors = result.uint_32;
@@ -366,151 +365,208 @@ static int exfat_read_root(struct inode *inode)
 	return 0;
 }
 
-static struct pbr *exfat_read_pbr_with_logical_sector(struct super_block *sb)
+static int exfat_calibrate_blocksize(struct super_block *sb, int logical_sect)
 {
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
-	struct pbr *p_pbr = (struct pbr *) (sbi->pbr_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;
+		exfat_err(sb, "bogus logical sector size %u", logical_sect);
+		return -EIO;
 	}
 
 	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;
+		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->pbr_bh);
-		sbi->pbr_bh = NULL;
+		brelse(sbi->boot_bh);
+		sbi->boot_bh = NULL;
 
 		if (!sb_set_blocksize(sb, logical_sect)) {
-			exfat_msg(sb, KERN_ERR,
-				"unable to set blocksize %u", logical_sect);
-			return NULL;
+			exfat_err(sb, "unable to set blocksize %u",
+				  logical_sect);
+			return -EIO;
 		}
-		sbi->pbr_bh = sb_bread(sb, 0);
-		if (!sbi->pbr_bh) {
-			exfat_msg(sb, KERN_ERR,
-				"unable to read boot sector (logical sector size = %lu)",
-				sb->s_blocksize);
-			return NULL;
+		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;
 		}
-
-		p_pbr = (struct pbr *)sbi->pbr_bh->b_data;
 	}
-	return p_pbr;
+	return 0;
 }
 
-/* mount the file system volume */
-static int __exfat_fill_super(struct super_block *sb)
+static int exfat_read_boot_sector(struct super_block *sb)
 {
-	int ret;
-	struct pbr *p_pbr;
-	struct pbr64 *p_bpb;
+	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->pbr_bh = sb_bread(sb, 0);
-	if (!sbi->pbr_bh) {
-		exfat_msg(sb, KERN_ERR, "unable to 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;
 
-	/* PRB is read */
-	p_pbr = (struct pbr *)sbi->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 the validity of BOOT */
+	if (le16_to_cpu((p_boot->signature)) != BOOT_SIGNATURE) {
+		exfat_err(sb, "invalid boot record signature");
+		return -EINVAL;
 	}
 
-
-	/* check logical sector size */
-	p_pbr = exfat_read_pbr_with_logical_sector(sb);
-	if (!p_pbr) {
-		ret = -EIO;
-		goto free_bh;
+	if (memcmp(p_boot->fs_name, STR_EXFAT, BOOTSEC_FS_NAME_LEN)) {
+		exfat_err(sb, "invalid fs_name"); /* fs_name may unprintable */
+		return -EINVAL;
 	}
 
 	/*
-	 * res_zero field must be filled with zero to prevent mounting
+	 * must_be_zero field must be filled with zero to prevent mounting
 	 * from FAT volume.
 	 */
-	if (memchr_inv(p_pbr->bpb.f64.res_zero, 0,
-			sizeof(p_pbr->bpb.f64.res_zero))) {
-		ret = -EINVAL;
-		goto free_bh;
-	}
+	if (memchr_inv(p_boot->must_be_zero, 0, sizeof(p_boot->must_be_zero)))
+		return -EINVAL;
 
-	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;
+	if (p_boot->num_fats != 1 && p_boot->num_fats != 2) {
+		exfat_err(sb, "bogus number of FAT structure");
+		return -EINVAL;
 	}
 
-	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->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_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->data_start_sector = le32_to_cpu(p_bpb->bsx.clu_offset);
-	sbi->num_sectors = le64_to_cpu(p_bpb->bsx.vol_length);
+	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_bpb->bsx.clu_count) +
+	sbi->num_clusters = le32_to_cpu(p_boot->clu_count) +
 		EXFAT_RESERVED_CLUSTERS;
 
-	sbi->root_dir = le32_to_cpu(p_bpb->bsx.root_cluster);
+	sbi->root_dir = le32_to_cpu(p_boot->root_cluster);
 	sbi->dentries_per_clu = 1 <<
 		(sbi->cluster_size_bits - DENTRY_SIZE_BITS);
 
-	sbi->vol_flag = le16_to_cpu(p_bpb->bsx.vol_flags);
+	sbi->vol_flag = le16_to_cpu(p_boot->vol_flags);
 	sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER;
 	sbi->used_clusters = EXFAT_CLUSTERS_UNTRACKED;
 
-	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.");
+	/* check consistencies */
+	if (sbi->num_FAT_sectors << p_boot->sect_size_bits <
+	    sbi->num_clusters * 4) {
+		exfat_err(sb, "bogus fat length");
+		return -EINVAL;
 	}
+	if (sbi->data_start_sector <
+	    sbi->FAT1_start_sector + sbi->num_FAT_sectors * p_boot->num_fats) {
+		exfat_err(sb, "bogus data start sector");
+		return -EINVAL;
+	}
+	if (sbi->vol_flag & VOL_DIRTY)
+		exfat_warn(sb, "Volume was not properly unmounted. Some data may be corrupt. Please run fsck.");
+	if (sbi->vol_flag & ERR_MEDIUM)
+		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_msg(sb, KERN_ERR, "failed to load upcase table");
+		exfat_err(sb, "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");
+		exfat_err(sb, "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");
+		exfat_err(sb, "failed to scan clusters");
 		goto free_alloc_bitmap;
 	}
 
@@ -521,7 +577,7 @@ free_alloc_bitmap:
 free_upcase_table:
 	exfat_free_upcase_table(sbi);
 free_bh:
-	brelse(sbi->pbr_bh);
+	brelse(sbi->boot_bh);
 	return ret;
 }
 
@@ -539,8 +595,7 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 		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");
+			exfat_warn(sb, "mounting with \"discard\" option, but the device does not support discard");
 			opts->discard = 0;
 		}
 	}
@@ -555,7 +610,7 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 
 	err = __exfat_fill_super(sb);
 	if (err) {
-		exfat_msg(sb, KERN_ERR, "failed to recognize exfat type");
+		exfat_err(sb, "failed to recognize exfat type");
 		goto check_nls_io;
 	}
 
@@ -567,8 +622,8 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 	else {
 		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);
+			exfat_err(sb, "IO charset %s not found",
+				  sbi->options.iocharset);
 			err = -EINVAL;
 			goto free_table;
 		}
@@ -581,7 +636,7 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 
 	root_inode = new_inode(sb);
 	if (!root_inode) {
-		exfat_msg(sb, KERN_ERR, "failed to allocate root inode.");
+		exfat_err(sb, "failed to allocate root inode");
 		err = -ENOMEM;
 		goto free_table;
 	}
@@ -590,7 +645,7 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 	inode_set_iversion(root_inode, 1);
 	err = exfat_read_root(root_inode);
 	if (err) {
-		exfat_msg(sb, KERN_ERR, "failed to initialize root inode.");
+		exfat_err(sb, "failed to initialize root inode");
 		goto put_inode;
 	}
 
@@ -599,7 +654,7 @@ static int exfat_fill_super(struct super_block *sb, struct fs_context *fc)
 
 	sb->s_root = d_make_root(root_inode);
 	if (!sb->s_root) {
-		exfat_msg(sb, KERN_ERR, "failed to get the root dentry");
+		exfat_err(sb, "failed to get the root dentry");
 		err = -ENOMEM;
 		goto put_inode;
 	}
@@ -613,7 +668,7 @@ put_inode:
 free_table:
 	exfat_free_upcase_table(sbi);
 	exfat_free_bitmap(sbi);
-	brelse(sbi->pbr_bh);
+	brelse(sbi->boot_bh);
 
 check_nls_io:
 	unload_nls(sbi->nls_io);
@@ -630,7 +685,12 @@ static int exfat_get_tree(struct fs_context *fc)
 
 static void exfat_free(struct fs_context *fc)
 {
-	kfree(fc->s_fs_info);
+	struct exfat_sb_info *sbi = fc->s_fs_info;
+
+	if (sbi) {
+		exfat_free_iocharset(sbi);
+		kfree(sbi);
+	}
 }
 
 static const struct fs_context_operations exfat_context_ops = {