281 lines
7.3 KiB
C
281 lines
7.3 KiB
C
/*
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* linux/fs/fat/misc.c
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*
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* Written 1992,1993 by Werner Almesberger
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* 22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980
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* and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru)
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*/
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/buffer_head.h>
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#include "fat.h"
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/*
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* fat_fs_panic reports a severe file system problem and sets the file system
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* read-only. The file system can be made writable again by remounting it.
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*/
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void fat_fs_panic(struct super_block *s, const char *fmt, ...)
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{
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va_list args;
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printk(KERN_ERR "FAT: Filesystem panic (dev %s)\n", s->s_id);
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printk(KERN_ERR " ");
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va_start(args, fmt);
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vprintk(fmt, args);
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va_end(args);
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printk("\n");
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if (!(s->s_flags & MS_RDONLY)) {
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s->s_flags |= MS_RDONLY;
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printk(KERN_ERR " File system has been set read-only\n");
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}
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}
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EXPORT_SYMBOL_GPL(fat_fs_panic);
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/* Flushes the number of free clusters on FAT32 */
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/* XXX: Need to write one per FSINFO block. Currently only writes 1 */
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void fat_clusters_flush(struct super_block *sb)
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{
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struct msdos_sb_info *sbi = MSDOS_SB(sb);
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struct buffer_head *bh;
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struct fat_boot_fsinfo *fsinfo;
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if (sbi->fat_bits != 32)
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return;
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bh = sb_bread(sb, sbi->fsinfo_sector);
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if (bh == NULL) {
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printk(KERN_ERR "FAT: bread failed in fat_clusters_flush\n");
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return;
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}
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fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
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/* Sanity check */
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if (!IS_FSINFO(fsinfo)) {
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printk(KERN_ERR "FAT: Invalid FSINFO signature: "
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"0x%08x, 0x%08x (sector = %lu)\n",
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le32_to_cpu(fsinfo->signature1),
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le32_to_cpu(fsinfo->signature2),
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sbi->fsinfo_sector);
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} else {
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if (sbi->free_clusters != -1)
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fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters);
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if (sbi->prev_free != -1)
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fsinfo->next_cluster = cpu_to_le32(sbi->prev_free);
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mark_buffer_dirty(bh);
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}
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brelse(bh);
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}
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/*
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* fat_chain_add() adds a new cluster to the chain of clusters represented
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* by inode.
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*/
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int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
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{
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struct super_block *sb = inode->i_sb;
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struct msdos_sb_info *sbi = MSDOS_SB(sb);
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int ret, new_fclus, last;
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/*
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* We must locate the last cluster of the file to add this new
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* one (new_dclus) to the end of the link list (the FAT).
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*/
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last = new_fclus = 0;
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if (MSDOS_I(inode)->i_start) {
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int fclus, dclus;
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ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
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if (ret < 0)
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return ret;
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new_fclus = fclus + 1;
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last = dclus;
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}
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/* add new one to the last of the cluster chain */
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if (last) {
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struct fat_entry fatent;
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fatent_init(&fatent);
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ret = fat_ent_read(inode, &fatent, last);
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if (ret >= 0) {
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int wait = inode_needs_sync(inode);
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ret = fat_ent_write(inode, &fatent, new_dclus, wait);
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fatent_brelse(&fatent);
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}
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if (ret < 0)
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return ret;
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// fat_cache_add(inode, new_fclus, new_dclus);
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} else {
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MSDOS_I(inode)->i_start = new_dclus;
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MSDOS_I(inode)->i_logstart = new_dclus;
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/*
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* Since generic_osync_inode() synchronize later if
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* this is not directory, we don't here.
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*/
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if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
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ret = fat_sync_inode(inode);
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if (ret)
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return ret;
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} else
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mark_inode_dirty(inode);
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}
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if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
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fat_fs_panic(sb, "clusters badly computed (%d != %llu)",
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new_fclus,
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(llu)(inode->i_blocks >> (sbi->cluster_bits - 9)));
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fat_cache_inval_inode(inode);
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}
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inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
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return 0;
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}
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extern struct timezone sys_tz;
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/*
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* The epoch of FAT timestamp is 1980.
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* : bits : value
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* date: 0 - 4: day (1 - 31)
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* date: 5 - 8: month (1 - 12)
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* date: 9 - 15: year (0 - 127) from 1980
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* time: 0 - 4: sec (0 - 29) 2sec counts
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* time: 5 - 10: min (0 - 59)
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* time: 11 - 15: hour (0 - 23)
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*/
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#define SECS_PER_MIN 60
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#define SECS_PER_HOUR (60 * 60)
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#define SECS_PER_DAY (SECS_PER_HOUR * 24)
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#define UNIX_SECS_1980 315532800L
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#if BITS_PER_LONG == 64
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#define UNIX_SECS_2108 4354819200L
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#endif
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/* days between 1.1.70 and 1.1.80 (2 leap days) */
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#define DAYS_DELTA (365 * 10 + 2)
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/* 120 (2100 - 1980) isn't leap year */
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#define YEAR_2100 120
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#define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100)
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/* Linear day numbers of the respective 1sts in non-leap years. */
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static time_t days_in_year[] = {
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/* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
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0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
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};
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/* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
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void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
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__le16 __time, __le16 __date, u8 time_cs)
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{
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u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
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time_t second, day, leap_day, month, year;
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year = date >> 9;
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month = max(1, (date >> 5) & 0xf);
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day = max(1, date & 0x1f) - 1;
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leap_day = (year + 3) / 4;
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if (year > YEAR_2100) /* 2100 isn't leap year */
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leap_day--;
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if (IS_LEAP_YEAR(year) && month > 2)
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leap_day++;
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second = (time & 0x1f) << 1;
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second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
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second += (time >> 11) * SECS_PER_HOUR;
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second += (year * 365 + leap_day
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+ days_in_year[month] + day
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+ DAYS_DELTA) * SECS_PER_DAY;
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if (!sbi->options.tz_utc)
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second += sys_tz.tz_minuteswest * SECS_PER_MIN;
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if (time_cs) {
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ts->tv_sec = second + (time_cs / 100);
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ts->tv_nsec = (time_cs % 100) * 10000000;
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} else {
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ts->tv_sec = second;
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ts->tv_nsec = 0;
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}
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}
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/* Convert linear UNIX date to a FAT time/date pair. */
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void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
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__le16 *time, __le16 *date, u8 *time_cs)
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{
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time_t second = ts->tv_sec;
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time_t day, leap_day, month, year;
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if (!sbi->options.tz_utc)
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second -= sys_tz.tz_minuteswest * SECS_PER_MIN;
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/* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
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if (second < UNIX_SECS_1980) {
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*time = 0;
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*date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
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if (time_cs)
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*time_cs = 0;
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return;
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}
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#if BITS_PER_LONG == 64
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if (second >= UNIX_SECS_2108) {
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*time = cpu_to_le16((23 << 11) | (59 << 5) | 29);
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*date = cpu_to_le16((127 << 9) | (12 << 5) | 31);
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if (time_cs)
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*time_cs = 199;
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return;
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}
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#endif
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day = second / SECS_PER_DAY - DAYS_DELTA;
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year = day / 365;
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leap_day = (year + 3) / 4;
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if (year > YEAR_2100) /* 2100 isn't leap year */
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leap_day--;
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if (year * 365 + leap_day > day)
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year--;
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leap_day = (year + 3) / 4;
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if (year > YEAR_2100) /* 2100 isn't leap year */
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leap_day--;
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day -= year * 365 + leap_day;
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if (IS_LEAP_YEAR(year) && day == days_in_year[3]) {
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month = 2;
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} else {
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if (IS_LEAP_YEAR(year) && day > days_in_year[3])
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day--;
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for (month = 1; month < 12; month++) {
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if (days_in_year[month + 1] > day)
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break;
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}
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}
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day -= days_in_year[month];
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*time = cpu_to_le16(((second / SECS_PER_HOUR) % 24) << 11
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| ((second / SECS_PER_MIN) % 60) << 5
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| (second % SECS_PER_MIN) >> 1);
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*date = cpu_to_le16((year << 9) | (month << 5) | (day + 1));
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if (time_cs)
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*time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
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}
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EXPORT_SYMBOL_GPL(fat_time_unix2fat);
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int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
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{
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int i, err = 0;
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ll_rw_block(SWRITE, nr_bhs, bhs);
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for (i = 0; i < nr_bhs; i++) {
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wait_on_buffer(bhs[i]);
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if (buffer_eopnotsupp(bhs[i])) {
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clear_buffer_eopnotsupp(bhs[i]);
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err = -EOPNOTSUPP;
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} else if (!err && !buffer_uptodate(bhs[i]))
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err = -EIO;
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}
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return err;
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}
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