diff options
Diffstat (limited to 'fs/fat/misc.c')
| -rw-r--r-- | fs/fat/misc.c | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/fs/fat/misc.c b/fs/fat/misc.c new file mode 100644 index 00000000000..2a0df2122f5 --- /dev/null +++ b/fs/fat/misc.c @@ -0,0 +1,225 @@ +/* + * 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(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: Did not find valid FSINFO signature.\n" + " Found signature1 0x%08x signature2 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); + if (sb->s_flags & MS_SYNCHRONOUS) + sync_dirty_buffer(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 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 */ + 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 day, year, nl_day, month; + + 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(fat_date_unix2dos); + +int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) +{ + int i, e, err = 0; + + for (i = 0; i < nr_bhs; i++) { + lock_buffer(bhs[i]); + if (test_clear_buffer_dirty(bhs[i])) { + get_bh(bhs[i]); + bhs[i]->b_end_io = end_buffer_write_sync; + e = submit_bh(WRITE, bhs[i]); + if (!err && e) + err = e; + } else + unlock_buffer(bhs[i]); + } + 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; +} + +EXPORT_SYMBOL(fat_sync_bhs); |