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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Written 1992,1993 by Werner Almesberger4 * 22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/19805 * and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru)6 * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.7 */8 9#include <linux/time.h>10#include <linux/fs.h>11#include <linux/slab.h>12#include <linux/buffer_head.h>13#include <linux/blk_types.h>14 15#include "exfat_raw.h"16#include "exfat_fs.h"17 18/*19 * exfat_fs_error reports a file system problem that might indicate fa data20 * corruption/inconsistency. Depending on 'errors' mount option the21 * panic() is called, or error message is printed FAT and nothing is done,22 * or filesystem is remounted read-only (default behavior).23 * In case the file system is remounted read-only, it can be made writable24 * again by remounting it.25 */26void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)27{28 struct exfat_mount_options *opts = &EXFAT_SB(sb)->options;29 va_list args;30 struct va_format vaf;31 32 if (report) {33 va_start(args, fmt);34 vaf.fmt = fmt;35 vaf.va = &args;36 exfat_err(sb, "error, %pV", &vaf);37 va_end(args);38 }39 40 if (opts->errors == EXFAT_ERRORS_PANIC) {41 panic("exFAT-fs (%s): fs panic from previous error\n",42 sb->s_id);43 } else if (opts->errors == EXFAT_ERRORS_RO && !sb_rdonly(sb)) {44 sb->s_flags |= SB_RDONLY;45 exfat_err(sb, "Filesystem has been set read-only");46 }47}48 49#define SECS_PER_MIN (60)50#define TIMEZONE_SEC(x) ((x) * 15 * SECS_PER_MIN)51 52static void exfat_adjust_tz(struct timespec64 *ts, u8 tz_off)53{54 if (tz_off <= 0x3F)55 ts->tv_sec -= TIMEZONE_SEC(tz_off);56 else /* 0x40 <= (tz_off & 0x7F) <=0x7F */57 ts->tv_sec += TIMEZONE_SEC(0x80 - tz_off);58}59 60static inline int exfat_tz_offset(struct exfat_sb_info *sbi)61{62 if (sbi->options.sys_tz)63 return -sys_tz.tz_minuteswest;64 return sbi->options.time_offset;65}66 67/* Convert a EXFAT time/date pair to a UNIX date (seconds since 1 1 70). */68void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,69 u8 tz, __le16 time, __le16 date, u8 time_cs)70{71 u16 t = le16_to_cpu(time);72 u16 d = le16_to_cpu(date);73 74 ts->tv_sec = mktime64(1980 + (d >> 9), d >> 5 & 0x000F, d & 0x001F,75 t >> 11, (t >> 5) & 0x003F, (t & 0x001F) << 1);76 77 78 /* time_cs field represent 0 ~ 199cs(1990 ms) */79 if (time_cs) {80 ts->tv_sec += time_cs / 100;81 ts->tv_nsec = (time_cs % 100) * 10 * NSEC_PER_MSEC;82 } else83 ts->tv_nsec = 0;84 85 if (tz & EXFAT_TZ_VALID)86 /* Adjust timezone to UTC0. */87 exfat_adjust_tz(ts, tz & ~EXFAT_TZ_VALID);88 else89 ts->tv_sec -= exfat_tz_offset(sbi) * SECS_PER_MIN;90}91 92/* Convert linear UNIX date to a EXFAT time/date pair. */93void exfat_set_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,94 u8 *tz, __le16 *time, __le16 *date, u8 *time_cs)95{96 struct tm tm;97 u16 t, d;98 99 time64_to_tm(ts->tv_sec, 0, &tm);100 t = (tm.tm_hour << 11) | (tm.tm_min << 5) | (tm.tm_sec >> 1);101 d = ((tm.tm_year - 80) << 9) | ((tm.tm_mon + 1) << 5) | tm.tm_mday;102 103 *time = cpu_to_le16(t);104 *date = cpu_to_le16(d);105 106 /* time_cs field represent 0 ~ 199cs(1990 ms) */107 if (time_cs)108 *time_cs = (tm.tm_sec & 1) * 100 +109 ts->tv_nsec / (10 * NSEC_PER_MSEC);110 111 /*112 * Record 00h value for OffsetFromUtc field and 1 value for OffsetValid113 * to indicate that local time and UTC are the same.114 */115 *tz = EXFAT_TZ_VALID;116}117 118/*119 * The timestamp for access_time has double seconds granularity.120 * (There is no 10msIncrement field for access_time unlike create/modify_time)121 * atime also has only a 2-second resolution.122 */123void exfat_truncate_atime(struct timespec64 *ts)124{125 ts->tv_sec = round_down(ts->tv_sec, 2);126 ts->tv_nsec = 0;127}128 129void exfat_truncate_inode_atime(struct inode *inode)130{131 struct timespec64 atime = inode_get_atime(inode);132 133 exfat_truncate_atime(&atime);134 inode_set_atime_to_ts(inode, atime);135}136 137u16 exfat_calc_chksum16(void *data, int len, u16 chksum, int type)138{139 int i;140 u8 *c = (u8 *)data;141 142 for (i = 0; i < len; i++, c++) {143 if (unlikely(type == CS_DIR_ENTRY && (i == 2 || i == 3)))144 continue;145 chksum = ((chksum << 15) | (chksum >> 1)) + *c;146 }147 return chksum;148}149 150u32 exfat_calc_chksum32(void *data, int len, u32 chksum, int type)151{152 int i;153 u8 *c = (u8 *)data;154 155 for (i = 0; i < len; i++, c++) {156 if (unlikely(type == CS_BOOT_SECTOR &&157 (i == 106 || i == 107 || i == 112)))158 continue;159 chksum = ((chksum << 31) | (chksum >> 1)) + *c;160 }161 return chksum;162}163 164void exfat_update_bh(struct buffer_head *bh, int sync)165{166 set_buffer_uptodate(bh);167 mark_buffer_dirty(bh);168 169 if (sync)170 sync_dirty_buffer(bh);171}172 173int exfat_update_bhs(struct buffer_head **bhs, int nr_bhs, int sync)174{175 int i, err = 0;176 177 for (i = 0; i < nr_bhs; i++) {178 set_buffer_uptodate(bhs[i]);179 mark_buffer_dirty(bhs[i]);180 if (sync)181 write_dirty_buffer(bhs[i], REQ_SYNC);182 }183 184 for (i = 0; i < nr_bhs && sync; i++) {185 wait_on_buffer(bhs[i]);186 if (!err && !buffer_uptodate(bhs[i]))187 err = -EIO;188 }189 return err;190}191 192void exfat_chain_set(struct exfat_chain *ec, unsigned int dir,193 unsigned int size, unsigned char flags)194{195 ec->dir = dir;196 ec->size = size;197 ec->flags = flags;198}199 200void exfat_chain_dup(struct exfat_chain *dup, struct exfat_chain *ec)201{202 return exfat_chain_set(dup, ec->dir, ec->size, ec->flags);203}204