1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * Written 1992,1993 by Werner Almesberger 4 * 22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980 5 * 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 14#include "exfat_raw.h" 15#include "exfat_fs.h" 16 17/* 18 * exfat_fs_error reports a file system problem that might indicate fa data 19 * corruption/inconsistency. Depending on 'errors' mount option the 20 * panic() is called, or error message is printed FAT and nothing is done, 21 * or filesystem is remounted read-only (default behavior). 22 * In case the file system is remounted read-only, it can be made writable 23 * again by remounting it. 24 */ 25void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...) 26{ 27 struct exfat_mount_options *opts = &EXFAT_SB(sb)->options; 28 va_list args; 29 struct va_format vaf; 30 31 if (report) { 32 va_start(args, fmt); 33 vaf.fmt = fmt; 34 vaf.va = &args; 35 exfat_err(sb, "error, %pV", &vaf); 36 va_end(args); 37 } 38 39 if (opts->errors == EXFAT_ERRORS_PANIC) { 40 panic("exFAT-fs (%s): fs panic from previous error\n", 41 sb->s_id); 42 } else if (opts->errors == EXFAT_ERRORS_RO && !sb_rdonly(sb)) { 43 sb->s_flags |= SB_RDONLY; 44 exfat_err(sb, "Filesystem has been set read-only"); 45 } 46} 47 48/* 49 * exfat_msg() - print preformated EXFAT specific messages. 50 * All logs except what uses exfat_fs_error() should be written by exfat_msg() 51 */ 52void exfat_msg(struct super_block *sb, const char *level, const char *fmt, ...) 53{ 54 struct va_format vaf; 55 va_list args; 56 57 va_start(args, fmt); 58 vaf.fmt = fmt; 59 vaf.va = &args; 60 /* level means KERN_ pacility level */ 61 printk("%sexFAT-fs (%s): %pV\n", level, sb->s_id, &vaf); 62 va_end(args); 63} 64 65#define SECS_PER_MIN (60) 66#define TIMEZONE_SEC(x) ((x) * 15 * SECS_PER_MIN) 67 68static void exfat_adjust_tz(struct timespec64 *ts, u8 tz_off) 69{ 70 if (tz_off <= 0x3F) 71 ts->tv_sec -= TIMEZONE_SEC(tz_off); 72 else /* 0x40 <= (tz_off & 0x7F) <=0x7F */ 73 ts->tv_sec += TIMEZONE_SEC(0x80 - tz_off); 74} 75 76/* Convert a EXFAT time/date pair to a UNIX date (seconds since 1 1 70). */ 77void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts, 78 u8 tz, __le16 time, __le16 date, u8 time_cs) 79{ 80 u16 t = le16_to_cpu(time); 81 u16 d = le16_to_cpu(date); 82 83 ts->tv_sec = mktime64(1980 + (d >> 9), d >> 5 & 0x000F, d & 0x001F, 84 t >> 11, (t >> 5) & 0x003F, (t & 0x001F) << 1); 85 86 87 /* time_cs field represent 0 ~ 199cs(1990 ms) */ 88 if (time_cs) { 89 ts->tv_sec += time_cs / 100; 90 ts->tv_nsec = (time_cs % 100) * 10 * NSEC_PER_MSEC; 91 } else 92 ts->tv_nsec = 0; 93 94 if (tz & EXFAT_TZ_VALID) 95 /* Adjust timezone to UTC0. */ 96 exfat_adjust_tz(ts, tz & ~EXFAT_TZ_VALID); 97 else 98 /* Convert from local time to UTC using time_offset. */ 99 ts->tv_sec -= sbi->options.time_offset * SECS_PER_MIN; 100} 101 102/* Convert linear UNIX date to a EXFAT time/date pair. */ 103void exfat_set_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts, 104 u8 *tz, __le16 *time, __le16 *date, u8 *time_cs) 105{ 106 struct tm tm; 107 u16 t, d; 108 109 time64_to_tm(ts->tv_sec, 0, &tm); 110 t = (tm.tm_hour << 11) | (tm.tm_min << 5) | (tm.tm_sec >> 1); 111 d = ((tm.tm_year - 80) << 9) | ((tm.tm_mon + 1) << 5) | tm.tm_mday; 112 113 *time = cpu_to_le16(t); 114 *date = cpu_to_le16(d); 115 116 /* time_cs field represent 0 ~ 199cs(1990 ms) */ 117 if (time_cs) 118 *time_cs = (tm.tm_sec & 1) * 100 + 119 ts->tv_nsec / (10 * NSEC_PER_MSEC); 120 121 /* 122 * Record 00h value for OffsetFromUtc field and 1 value for OffsetValid 123 * to indicate that local time and UTC are the same. 124 */ 125 *tz = EXFAT_TZ_VALID; 126} 127 128/* 129 * The timestamp for access_time has double seconds granularity. 130 * (There is no 10msIncrement field for access_time unlike create/modify_time) 131 * atime also has only a 2-second resolution. 132 */ 133void exfat_truncate_atime(struct timespec64 *ts) 134{ 135 ts->tv_sec = round_down(ts->tv_sec, 2); 136 ts->tv_nsec = 0; 137} 138 139u16 exfat_calc_chksum16(void *data, int len, u16 chksum, int type) 140{ 141 int i; 142 u8 *c = (u8 *)data; 143 144 for (i = 0; i < len; i++, c++) { 145 if (unlikely(type == CS_DIR_ENTRY && (i == 2 || i == 3))) 146 continue; 147 chksum = ((chksum << 15) | (chksum >> 1)) + *c; 148 } 149 return chksum; 150} 151 152u32 exfat_calc_chksum32(void *data, int len, u32 chksum, int type) 153{ 154 int i; 155 u8 *c = (u8 *)data; 156 157 for (i = 0; i < len; i++, c++) { 158 if (unlikely(type == CS_BOOT_SECTOR && 159 (i == 106 || i == 107 || i == 112))) 160 continue; 161 chksum = ((chksum << 31) | (chksum >> 1)) + *c; 162 } 163 return chksum; 164} 165 166void exfat_update_bh(struct buffer_head *bh, int sync) 167{ 168 set_buffer_uptodate(bh); 169 mark_buffer_dirty(bh); 170 171 if (sync) 172 sync_dirty_buffer(bh); 173} 174 175int exfat_update_bhs(struct buffer_head **bhs, int nr_bhs, int sync) 176{ 177 int i, err = 0; 178 179 for (i = 0; i < nr_bhs; i++) { 180 set_buffer_uptodate(bhs[i]); 181 mark_buffer_dirty(bhs[i]); 182 if (sync) 183 write_dirty_buffer(bhs[i], 0); 184 } 185 186 for (i = 0; i < nr_bhs && sync; i++) { 187 wait_on_buffer(bhs[i]); 188 if (!err && !buffer_uptodate(bhs[i])) 189 err = -EIO; 190 } 191 return err; 192} 193 194void exfat_chain_set(struct exfat_chain *ec, unsigned int dir, 195 unsigned int size, unsigned char flags) 196{ 197 ec->dir = dir; 198 ec->size = size; 199 ec->flags = flags; 200} 201 202void exfat_chain_dup(struct exfat_chain *dup, struct exfat_chain *ec) 203{ 204 return exfat_chain_set(dup, ec->dir, ec->size, ec->flags); 205} 206