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exfat: standardize checksum calculation

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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: Tetsuhiro Kohada <kohada.t2@gmail.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
This commit is contained in:
Tetsuhiro Kohada 2020-05-31 21:04:00 +09:00 committed by Namjae Jeon
parent af08f9af6f
commit 149ef0460e
4 changed files with 19 additions and 27 deletions
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12
dir.c
View File

@ -496,7 +496,7 @@ 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 +505,7 @@ 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 +513,7 @@ 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);
}
@ -598,8 +598,8 @@ 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_type);
chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
chksum_type);
chksum_type = CS_DEFAULT;
}
ep = exfat_get_dentry_cached(es, 0);
@ -1005,7 +1005,7 @@ rewind:
}
if (entry_type == TYPE_STREAM) {
unsigned short name_hash;
u16 name_hash;
if (step != DIRENT_STEP_STRM) {
step = DIRENT_STEP_FILE;

5
exfat_fs.h
View File

@ -138,7 +138,7 @@ 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;
};
@ -519,8 +519,7 @@ 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,

10
misc.c
View File

@ -142,17 +142,15 @@ 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;
}

19
nls.c
View File

@ -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);