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linux-sg2042/fs/fat/misc.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/fs/fat/misc.c
*
* 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)
*/
#include "fat.h"
#include <linux/iversion.h>
/*
* fat_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 __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
{
struct fat_mount_options *opts = &MSDOS_SB(sb)->options;
va_list args;
struct va_format vaf;
if (report) {
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
fat_msg(sb, KERN_ERR, "error, %pV", &vaf);
va_end(args);
}
if (opts->errors == FAT_ERRORS_PANIC)
panic("FAT-fs (%s): fs panic from previous error\n", sb->s_id);
else if (opts->errors == FAT_ERRORS_RO && !sb_rdonly(sb)) {
sb->s_flags |= SB_RDONLY;
fat_msg(sb, KERN_ERR, "Filesystem has been set read-only");
}
}
EXPORT_SYMBOL_GPL(__fat_fs_error);
/**
* fat_msg() - print preformated FAT specific messages. Every thing what is
* not fat_fs_error() should be fat_msg().
*/
void fat_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;
printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf);
va_end(args);
}
/* Flushes the number of free clusters on FAT32 */
/* XXX: Need to write one per FSINFO block. Currently only writes 1 */
int fat_clusters_flush(struct super_block *sb)
{
struct msdos_sb_info *sbi = MSDOS_SB(sb);
struct buffer_head *bh;
struct fat_boot_fsinfo *fsinfo;
if (!is_fat32(sbi))
return 0;
bh = sb_bread(sb, sbi->fsinfo_sector);
if (bh == NULL) {
fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush");
return -EIO;
}
fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
/* Sanity check */
if (!IS_FSINFO(fsinfo)) {
fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: "
"0x%08x, 0x%08x (sector = %lu)",
le32_to_cpu(fsinfo->signature1),
le32_to_cpu(fsinfo->signature2),
sbi->fsinfo_sector);
} else {
if (sbi->free_clusters != -1)
fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters);
if (sbi->prev_free != -1)
fsinfo->next_cluster = cpu_to_le32(sbi->prev_free);
mark_buffer_dirty(bh);
}
brelse(bh);
return 0;
}
/*
* fat_chain_add() adds a new cluster to the chain of clusters represented
* by inode.
*/
int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
{
struct super_block *sb = inode->i_sb;
struct msdos_sb_info *sbi = MSDOS_SB(sb);
int ret, new_fclus, last;
/*
* We must locate the last cluster of the file to add this new
* one (new_dclus) to the end of the link list (the FAT).
*/
last = new_fclus = 0;
if (MSDOS_I(inode)->i_start) {
int fclus, dclus;
ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
if (ret < 0)
return ret;
new_fclus = fclus + 1;
last = dclus;
}
/* add new one to the last of the cluster chain */
if (last) {
struct fat_entry fatent;
fatent_init(&fatent);
ret = fat_ent_read(inode, &fatent, last);
if (ret >= 0) {
int wait = inode_needs_sync(inode);
ret = fat_ent_write(inode, &fatent, new_dclus, wait);
fatent_brelse(&fatent);
}
if (ret < 0)
return ret;
/*
* FIXME:Although we can add this cache, fat_cache_add() is
* assuming to be called after linear search with fat_cache_id.
*/
// fat_cache_add(inode, new_fclus, new_dclus);
} else {
MSDOS_I(inode)->i_start = new_dclus;
MSDOS_I(inode)->i_logstart = new_dclus;
/*
* Since generic_write_sync() synchronizes regular files later,
* we sync here only directories.
*/
if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
ret = fat_sync_inode(inode);
if (ret)
return ret;
} else
mark_inode_dirty(inode);
}
if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
fat_fs_error(sb, "clusters badly computed (%d != %llu)",
new_fclus,
(llu)(inode->i_blocks >> (sbi->cluster_bits - 9)));
fat_cache_inval_inode(inode);
}
inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
return 0;
}
/*
* The epoch of FAT timestamp is 1980.
* : bits : value
* date: 0 - 4: day (1 - 31)
* date: 5 - 8: month (1 - 12)
* date: 9 - 15: year (0 - 127) from 1980
* time: 0 - 4: sec (0 - 29) 2sec counts
* time: 5 - 10: min (0 - 59)
* time: 11 - 15: hour (0 - 23)
*/
#define SECS_PER_MIN 60
#define SECS_PER_HOUR (60 * 60)
#define SECS_PER_DAY (SECS_PER_HOUR * 24)
/* days between 1.1.70 and 1.1.80 (2 leap days) */
#define DAYS_DELTA (365 * 10 + 2)
/* 120 (2100 - 1980) isn't leap year */
#define YEAR_2100 120
#define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100)
/* Linear day numbers of the respective 1sts in non-leap years. */
static long days_in_year[] = {
/* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
};
static inline int fat_tz_offset(struct msdos_sb_info *sbi)
{
return (sbi->options.tz_set ?
-sbi->options.time_offset :
sys_tz.tz_minuteswest) * SECS_PER_MIN;
}
/* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts,
__le16 __time, __le16 __date, u8 time_cs)
{
u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
time64_t second;
long day, leap_day, month, year;
year = date >> 9;
month = max(1, (date >> 5) & 0xf);
day = max(1, date & 0x1f) - 1;
leap_day = (year + 3) / 4;
if (year > YEAR_2100) /* 2100 isn't leap year */
leap_day--;
if (IS_LEAP_YEAR(year) && month > 2)
leap_day++;
second = (time & 0x1f) << 1;
second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
second += (time >> 11) * SECS_PER_HOUR;
second += (time64_t)(year * 365 + leap_day
+ days_in_year[month] + day
+ DAYS_DELTA) * SECS_PER_DAY;
second += fat_tz_offset(sbi);
if (time_cs) {
ts->tv_sec = second + (time_cs / 100);
ts->tv_nsec = (time_cs % 100) * 10000000;
} else {
ts->tv_sec = second;
ts->tv_nsec = 0;
}
}
/* Convert linear UNIX date to a FAT time/date pair. */
void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,
__le16 *time, __le16 *date, u8 *time_cs)
{
struct tm tm;
time64_to_tm(ts->tv_sec, -fat_tz_offset(sbi), &tm);
/* FAT can only support year between 1980 to 2107 */
if (tm.tm_year < 1980 - 1900) {
*time = 0;
*date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
if (time_cs)
*time_cs = 0;
return;
}
if (tm.tm_year > 2107 - 1900) {
*time = cpu_to_le16((23 << 11) | (59 << 5) | 29);
*date = cpu_to_le16((127 << 9) | (12 << 5) | 31);
if (time_cs)
*time_cs = 199;
return;
}
/* from 1900 -> from 1980 */
tm.tm_year -= 80;
/* 0~11 -> 1~12 */
tm.tm_mon++;
/* 0~59 -> 0~29(2sec counts) */
tm.tm_sec >>= 1;
*time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec);
*date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday);
if (time_cs)
*time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
}
EXPORT_SYMBOL_GPL(fat_time_unix2fat);
static inline struct timespec64 fat_timespec64_trunc_2secs(struct timespec64 ts)
{
return (struct timespec64){ ts.tv_sec & ~1ULL, 0 };
}
static inline struct timespec64 fat_timespec64_trunc_10ms(struct timespec64 ts)
{
if (ts.tv_nsec)
ts.tv_nsec -= ts.tv_nsec % 10000000UL;
return ts;
}
/*
* truncate the various times with appropriate granularity:
* root inode:
* all times always 0
* all other inodes:
* mtime - 2 seconds
* ctime
* msdos - 2 seconds
* vfat - 10 milliseconds
* atime - 24 hours (00:00:00 in local timezone)
*/
int fat_truncate_time(struct inode *inode, struct timespec64 *now, int flags)
{
struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
struct timespec64 ts;
if (inode->i_ino == MSDOS_ROOT_INO)
return 0;
if (now == NULL) {
now = &ts;
ts = current_time(inode);
}
if (flags & S_ATIME) {
/* to localtime */
time64_t seconds = now->tv_sec - fat_tz_offset(sbi);
s32 remainder;
div_s64_rem(seconds, SECS_PER_DAY, &remainder);
/* to day boundary, and back to unix time */
seconds = seconds + fat_tz_offset(sbi) - remainder;
inode->i_atime = (struct timespec64){ seconds, 0 };
}
if (flags & S_CTIME) {
if (sbi->options.isvfat)
inode->i_ctime = fat_timespec64_trunc_10ms(*now);
else
inode->i_ctime = fat_timespec64_trunc_2secs(*now);
}
if (flags & S_MTIME)
inode->i_mtime = fat_timespec64_trunc_2secs(*now);
return 0;
}
EXPORT_SYMBOL_GPL(fat_truncate_time);
int fat_update_time(struct inode *inode, struct timespec64 *now, int flags)
{
int dirty_flags = 0;
if (inode->i_ino == MSDOS_ROOT_INO)
return 0;
if (flags & (S_ATIME | S_CTIME | S_MTIME)) {
fat_truncate_time(inode, now, flags);
if (inode->i_sb->s_flags & SB_LAZYTIME)
dirty_flags |= I_DIRTY_TIME;
else
dirty_flags |= I_DIRTY_SYNC;
}
if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false))
dirty_flags |= I_DIRTY_SYNC;
__mark_inode_dirty(inode, dirty_flags);
return 0;
}
EXPORT_SYMBOL_GPL(fat_update_time);
int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
{
int i, err = 0;
for (i = 0; i < nr_bhs; i++)
write_dirty_buffer(bhs[i], 0);
for (i = 0; i < nr_bhs; i++) {
wait_on_buffer(bhs[i]);
if (!err && !buffer_uptodate(bhs[i]))
err = -EIO;
}
return err;
}
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