diff options
Diffstat (limited to 'kernel/fs/fat/misc.c')
| -rw-r--r-- | kernel/fs/fat/misc.c | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/kernel/fs/fat/misc.c b/kernel/fs/fat/misc.c new file mode 100644 index 000000000..c4589e981 --- /dev/null +++ b/kernel/fs/fat/misc.c @@ -0,0 +1,278 @@ +/* + * 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" + +/* + * 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->s_flags & MS_RDONLY)) { + sb->s_flags |= MS_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 (sbi->fat_bits != 32) + 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 time_t 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, +}; + +/* 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 timespec *ts, + __le16 __time, __le16 __date, u8 time_cs) +{ + u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date); + time_t second, 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 += (year * 365 + leap_day + + days_in_year[month] + day + + DAYS_DELTA) * SECS_PER_DAY; + + if (!sbi->options.tz_set) + second += sys_tz.tz_minuteswest * SECS_PER_MIN; + else + second -= sbi->options.time_offset * SECS_PER_MIN; + + 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 timespec *ts, + __le16 *time, __le16 *date, u8 *time_cs) +{ + struct tm tm; + time_to_tm(ts->tv_sec, + (sbi->options.tz_set ? sbi->options.time_offset : + -sys_tz.tz_minuteswest) * SECS_PER_MIN, &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); + +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], WRITE); + + for (i = 0; i < nr_bhs; i++) { + wait_on_buffer(bhs[i]); + if (!err && !buffer_uptodate(bhs[i])) + err = -EIO; + } + return err; +} |