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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Written 1992,1993 by Werner Almesberger
* 22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980
* and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru)
* Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
*/
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/buffer_head.h>
#include "exfat_raw.h"
#include "exfat_fs.h"
/*
* exfat_fs_error reports a file system problem that might indicate fa data
* corruption/inconsistency. Depending on 'errors' mount option the
* panic() is called, or error message is printed FAT and nothing is done,
* or filesystem is remounted read-only (default behavior).
* In case the file system is remounted read-only, it can be made writable
* again by remounting it.
*/
void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
{
struct exfat_mount_options *opts = &EXFAT_SB(sb)->options;
va_list args;
struct va_format vaf;
if (report) {
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
exfat_err(sb, "error, %pV", &vaf);
va_end(args);
}
if (opts->errors == EXFAT_ERRORS_PANIC) {
panic("exFAT-fs (%s): fs panic from previous error\n",
sb->s_id);
} else if (opts->errors == EXFAT_ERRORS_RO && !sb_rdonly(sb)) {
sb->s_flags |= SB_RDONLY;
exfat_err(sb, "Filesystem has been set read-only");
}
}
/*
* exfat_msg() - print preformated EXFAT specific messages.
* All logs except what uses exfat_fs_error() should be written by exfat_msg()
*/
void exfat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
{
struct va_format vaf;
va_list args;
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
/* level means KERN_ pacility level */
printk("%sexFAT-fs (%s): %pV\n", level, sb->s_id, &vaf);
va_end(args);
}
#define SECS_PER_MIN (60)
#define TIMEZONE_SEC(x) ((x) * 15 * SECS_PER_MIN)
static void exfat_adjust_tz(struct timespec64 *ts, u8 tz_off)
{
if (tz_off <= 0x3F)
ts->tv_sec -= TIMEZONE_SEC(tz_off);
else /* 0x40 <= (tz_off & 0x7F) <=0x7F */
ts->tv_sec += TIMEZONE_SEC(0x80 - 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_cs)
{
u16 t = le16_to_cpu(time);
u16 d = le16_to_cpu(date);
ts->tv_sec = mktime64(1980 + (d >> 9), d >> 5 & 0x000F, d & 0x001F,
t >> 11, (t >> 5) & 0x003F, (t & 0x001F) << 1);
/* 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;
if (tz & EXFAT_TZ_VALID)
/* Adjust timezone to UTC0. */
exfat_adjust_tz(ts, tz & ~EXFAT_TZ_VALID);
else
/* Convert from local time to UTC using time_offset. */
ts->tv_sec -= sbi->options.time_offset * SECS_PER_MIN;
}
/* 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_cs)
{
struct tm tm;
u16 t, d;
time64_to_tm(ts->tv_sec, 0, &tm);
t = (tm.tm_hour << 11) | (tm.tm_min << 5) | (tm.tm_sec >> 1);
d = ((tm.tm_year - 80) << 9) | ((tm.tm_mon + 1) << 5) | tm.tm_mday;
*time = cpu_to_le16(t);
*date = cpu_to_le16(d);
/* 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);
/*
* Record 00h value for OffsetFromUtc field and 1 value for OffsetValid
* to indicate that local time and UTC are the same.
*/
*tz = EXFAT_TZ_VALID;
}
/*
* The timestamp for access_time has double seconds granularity.
* (There is no 10msIncrement field for access_time unlike create/modify_time)
* atime also has only a 2-second resolution.
*/
void exfat_truncate_atime(struct timespec64 *ts)
{
ts->tv_sec = round_down(ts->tv_sec, 2);
ts->tv_nsec = 0;
}
u16 exfat_calc_chksum16(void *data, int len, u16 chksum, int type)
{
int i;
u8 *c = (u8 *)data;
for (i = 0; i < len; i++, c++) {
if (unlikely(type == CS_DIR_ENTRY && (i == 2 || i == 3)))
continue;
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;
}
void exfat_update_bh(struct super_block *sb, struct buffer_head *bh, int sync)
{
set_bit(EXFAT_SB_DIRTY, &EXFAT_SB(sb)->s_state);
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
if (sync)
sync_dirty_buffer(bh);
}
void exfat_chain_set(struct exfat_chain *ec, unsigned int dir,
unsigned int size, unsigned char flags)
{
ec->dir = dir;
ec->size = size;
ec->flags = flags;
}
void exfat_chain_dup(struct exfat_chain *dup, struct exfat_chain *ec)
{
return exfat_chain_set(dup, ec->dir, ec->size, ec->flags);
}
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