From 772b29cca528fcb21374bb3e597d848779938d16 Mon Sep 17 00:00:00 2001

From: Namjae Jeon <namjae.jeon@samsung.com>

Date: Mon, 2 Mar 2020 15:21:40 +0900

Subject: [Backport 772b29cca528] exfat: add misc operations

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This adds the implementation of misc operations for exfat.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>

Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>

Reviewed-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Pali Rohár <pali.rohar@gmail.com>

Reviewed-by: Christoph Hellwig <hch@lst.de>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

---

 src/misc.c | 163 ++++++++++++++++++++++++++++++++++++++++++++++++

 1 file changed, 163 insertions(+)

 create mode 100644 src/misc.c

diff --git a/src/misc.c b/src/misc.c

new file mode 100644

index 0000000000000000000000000000000000000000..14a3300848f6a0fb754b9d34bdacbc31b90f5d07

--- /dev/null

+++ b/src/misc.c

@@ -0,0 +1,163 @@

+// 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 = &arg;;

+		exfat_msg(sb, KERN_ERR, "error, %pV\n", &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_msg(sb, KERN_ERR, "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 = &arg;;

+	/* 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_ms)

+{

+	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_ms field represent 0 ~ 199(1990 ms) */

+	if (time_ms) {

+		ts->tv_sec += time_ms / 100;

+		ts->tv_nsec = (time_ms % 100) * 10 * NSEC_PER_MSEC;

+	}

+

+	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_ms)

+{

+	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_ms field represent 0 ~ 199(1990 ms) */

+	if (time_ms)

+		*time_ms = (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;

+}

+

+unsigned short exfat_calc_chksum_2byte(void *data, int len,

+		unsigned short chksum, int type)

+{

+	int i;

+	unsigned char *c = (unsigned char *)data;

+

+	for (i = 0; i < len; i++, c++) {

+		if (((i == 2) || (i == 3)) && (type == CS_DIR_ENTRY))

+			continue;

+		chksum = (((chksum & 1) << 15) | ((chksum & 0xFFFE) >> 1)) +

+			(unsigned short)*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);

+}

-- 

2.31.1