diff options
Diffstat (limited to 'fs/exfat/misc.c')
| -rw-r--r-- | fs/exfat/misc.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/fs/exfat/misc.c b/fs/exfat/misc.c new file mode 100644 index 000000000000..2e1a1a6b1021 --- /dev/null +++ b/fs/exfat/misc.c @@ -0,0 +1,195 @@ +// 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 <linux/blk_types.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"); + } +} + +#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); +} + +static inline int exfat_tz_offset(struct exfat_sb_info *sbi) +{ + if (sbi->options.sys_tz) + return -sys_tz.tz_minuteswest; + return sbi->options.time_offset; +} + +/* 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 + ts->tv_sec -= exfat_tz_offset(sbi) * 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 buffer_head *bh, int sync) +{ + set_buffer_uptodate(bh); + mark_buffer_dirty(bh); + + if (sync) + sync_dirty_buffer(bh); +} + +int exfat_update_bhs(struct buffer_head **bhs, int nr_bhs, int sync) +{ + int i, err = 0; + + for (i = 0; i < nr_bhs; i++) { + set_buffer_uptodate(bhs[i]); + mark_buffer_dirty(bhs[i]); + if (sync) + write_dirty_buffer(bhs[i], REQ_SYNC); + } + + for (i = 0; i < nr_bhs && sync; i++) { + wait_on_buffer(bhs[i]); + if (!err && !buffer_uptodate(bhs[i])) + err = -EIO; + } + return err; +} + +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); +} |