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DEFINITIONS
This source file includes following definitions.
- fat_fs_panic
- fat_clusters_flush
- fat_chain_add
- date_dos2unix
- fat_date_unix2dos
- fat_sync_bhs
/*
* 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 <linux/module.h>
#include <linux/fs.h>
#include <linux/msdos_fs.h>
#include <linux/buffer_head.h>
/*
* fat_fs_panic reports a severe file system problem and sets the file system
* read-only. The file system can be made writable again by remounting it.
*/
void fat_fs_panic(struct super_block *s, const char *fmt, ...)
{
va_list args;
printk(KERN_ERR "FAT: Filesystem panic (dev %s)\n", s->s_id);
printk(KERN_ERR " ");
va_start(args, fmt);
vprintk(fmt, args);
va_end(args);
printk("\n");
if (!(s->s_flags & MS_RDONLY)) {
s->s_flags |= MS_RDONLY;
printk(KERN_ERR " File system has been set read-only\n");
}
}
EXPORT_SYMBOL_GPL(fat_fs_panic);
/* Flushes the number of free clusters on FAT32 */
/* XXX: Need to write one per FSINFO block. Currently only writes 1 */
void 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 (sbi->fat_bits != 32)
return;
bh = sb_bread(sb, sbi->fsinfo_sector);
if (bh == NULL) {
printk(KERN_ERR "FAT: bread failed in fat_clusters_flush\n");
return;
}
fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
/* Sanity check */
if (!IS_FSINFO(fsinfo)) {
printk(KERN_ERR "FAT: Invalid FSINFO signature: "
"0x%08x, 0x%08x (sector = %lu)\n",
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);
}
/*
* 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;
// 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_osync_inode() synchronize later if
* this is not directory, we don't here.
*/
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_panic(sb, "clusters badly computed (%d != %lu)",
new_fclus, inode->i_blocks >> (sbi->cluster_bits - 9));
fat_cache_inval_inode(inode);
}
inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
return 0;
}
extern struct timezone sys_tz;
/* Linear day numbers of the respective 1sts in non-leap years. */
static int day_n[] = {
/* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 0
};
/* Convert a MS-DOS time/date pair to a UNIX date (seconds since 1 1 70). */
int date_dos2unix(unsigned short time, unsigned short date, int tz_utc)
{
int month, year, secs;
/*
* first subtract and mask after that... Otherwise, if
* date == 0, bad things happen
*/
month = ((date >> 5) - 1) & 15;
year = date >> 9;
secs = (time & 31)*2+60*((time >> 5) & 63)+(time >> 11)*3600+86400*
((date & 31)-1+day_n[month]+(year/4)+year*365-((year & 3) == 0 &&
month < 2 ? 1 : 0)+3653);
/* days since 1.1.70 plus 80's leap day */
if (!tz_utc)
secs += sys_tz.tz_minuteswest*60;
return secs;
}
/* Convert linear UNIX date to a MS-DOS time/date pair. */
void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date, int tz_utc)
{
int day, year, nl_day, month;
if (!tz_utc)
unix_date -= sys_tz.tz_minuteswest*60;
/* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
if (unix_date < 315532800)
unix_date = 315532800;
*time = cpu_to_le16((unix_date % 60)/2+(((unix_date/60) % 60) << 5)+
(((unix_date/3600) % 24) << 11));
day = unix_date/86400-3652;
year = day/365;
if ((year+3)/4+365*year > day)
year--;
day -= (year+3)/4+365*year;
if (day == 59 && !(year & 3)) {
nl_day = day;
month = 2;
} else {
nl_day = (year & 3) || day <= 59 ? day : day-1;
for (month = 0; month < 12; month++) {
if (day_n[month] > nl_day)
break;
}
}
*date = cpu_to_le16(nl_day-day_n[month-1]+1+(month << 5)+(year << 9));
}
EXPORT_SYMBOL_GPL(fat_date_unix2dos);
int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
{
int i, err = 0;
ll_rw_block(SWRITE, nr_bhs, bhs);
for (i = 0; i < nr_bhs; i++) {
wait_on_buffer(bhs[i]);
if (buffer_eopnotsupp(bhs[i])) {
clear_buffer_eopnotsupp(bhs[i]);
err = -EOPNOTSUPP;
} else if (!err && !buffer_uptodate(bhs[i]))
err = -EIO;
}
return err;
}