Commit 5875bf28 authored by Tetsuhiro Kohada's avatar Tetsuhiro Kohada Committed by Namjae Jeon
Browse files

exfat: standardize checksum calculation 



To clarify that it is a 16-bit checksum, the parts related to the 16-bit
checksum are renamed and change type to u16.
Furthermore, replace checksum calculation in exfat_load_upcase_table()
with exfat_calc_checksum32().

Signed-off-by: default avatarTetsuhiro Kohada <kohada.t2@gmail.com>
Reviewed-by: default avatarSungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: default avatarNamjae Jeon <namjae.jeon@samsung.com>
parent 476189c0

fs/exfat/dir.c

+6 −6
Original line number Diff line number Diff line
@@ -491,7 +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;
@@ -500,7 +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);
@@ -508,7 +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);

	}
@@ -593,7 +593,7 @@ void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es) 


	for (i = 0; i < es->num_entries; i++) {

		ep = exfat_get_dentry_cached(es, i);

		chksum = exfat_calc_chksum_2byte(ep, DENTRY_SIZE, chksum,

		chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,

					     chksum_type);

		chksum_type = CS_DEFAULT;

	}
@@ -1000,7 +1000,7 @@ rewind: 
			}



			if (entry_type == TYPE_STREAM) {

				unsigned short name_hash;

				u16 name_hash;



				if (step != DIRENT_STEP_STRM) {

					step = DIRENT_STEP_FILE;

fs/exfat/exfat_fs.h

+2 −3
Original line number Diff line number Diff line
@@ -137,7 +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;

};
@@ -512,8 +512,7 @@ void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts, 
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_cs);

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);

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,

fs/exfat/misc.c

+4 −6
Original line number Diff line number Diff line
@@ -136,17 +136,15 @@ 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;

}

fs/exfat/nls.c

+7 −12
Original line number Diff line number Diff line
@@ -527,7 +527,7 @@ 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)
@@ -623,7 +623,7 @@ 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)
@@ -655,7 +655,8 @@ 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;
@@ -681,13 +682,6 @@ 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;
@@ -701,13 +695,14 @@ static int exfat_load_upcase_table(struct super_block *sb, 
			}

		}

		brelse(bh);

		chksum = exfat_calc_chksum32(bh->b_data, i, chksum, CS_DEFAULT);

	}



	if (index >= 0xFFFF && utbl_checksum == checksum)

	if (index >= 0xFFFF && utbl_checksum == chksum)

		return 0;



	exfat_err(sb, "failed to load upcase table (idx : 0x%08x, chksum : 0x%08x, utbl_chksum : 0x%08x)",

		  index, checksum, utbl_checksum);

		  index, chksum, utbl_checksum);

	ret = -EINVAL;

free_table:

	exfat_free_upcase_table(sbi);

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