linux/fs/fat/misc.c
<<
>>
Prefs
   1/*
   2 *  linux/fs/fat/misc.c
   3 *
   4 *  Written 1992,1993 by Werner Almesberger
   5 *  22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980
   6 *               and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru)
   7 */
   8
   9#include <linux/module.h>
  10#include <linux/fs.h>
  11#include <linux/buffer_head.h>
  12#include <linux/time.h>
  13#include "fat.h"
  14
  15/*
  16 * fat_fs_error reports a file system problem that might indicate fa data
  17 * corruption/inconsistency. Depending on 'errors' mount option the
  18 * panic() is called, or error message is printed FAT and nothing is done,
  19 * or filesystem is remounted read-only (default behavior).
  20 * In case the file system is remounted read-only, it can be made writable
  21 * again by remounting it.
  22 */
  23void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
  24{
  25        struct fat_mount_options *opts = &MSDOS_SB(sb)->options;
  26        va_list args;
  27        struct va_format vaf;
  28
  29        if (report) {
  30                va_start(args, fmt);
  31                vaf.fmt = fmt;
  32                vaf.va = &args;
  33                printk(KERN_ERR "FAT-fs (%s): error, %pV\n", sb->s_id, &vaf);
  34                va_end(args);
  35        }
  36
  37        if (opts->errors == FAT_ERRORS_PANIC)
  38                panic("FAT-fs (%s): fs panic from previous error\n", sb->s_id);
  39        else if (opts->errors == FAT_ERRORS_RO && !(sb->s_flags & MS_RDONLY)) {
  40                sb->s_flags |= MS_RDONLY;
  41                printk(KERN_ERR "FAT-fs (%s): Filesystem has been "
  42                                "set read-only\n", sb->s_id);
  43        }
  44}
  45EXPORT_SYMBOL_GPL(__fat_fs_error);
  46
  47/**
  48 * fat_msg() - print preformated FAT specific messages. Every thing what is
  49 * not fat_fs_error() should be fat_msg().
  50 */
  51void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
  52{
  53        struct va_format vaf;
  54        va_list args;
  55
  56        va_start(args, fmt);
  57        vaf.fmt = fmt;
  58        vaf.va = &args;
  59        printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf);
  60        va_end(args);
  61}
  62
  63/* Flushes the number of free clusters on FAT32 */
  64/* XXX: Need to write one per FSINFO block.  Currently only writes 1 */
  65int fat_clusters_flush(struct super_block *sb)
  66{
  67        struct msdos_sb_info *sbi = MSDOS_SB(sb);
  68        struct buffer_head *bh;
  69        struct fat_boot_fsinfo *fsinfo;
  70
  71        if (sbi->fat_bits != 32)
  72                return 0;
  73
  74        bh = sb_bread(sb, sbi->fsinfo_sector);
  75        if (bh == NULL) {
  76                fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush");
  77                return -EIO;
  78        }
  79
  80        fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
  81        /* Sanity check */
  82        if (!IS_FSINFO(fsinfo)) {
  83                fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: "
  84                       "0x%08x, 0x%08x (sector = %lu)",
  85                       le32_to_cpu(fsinfo->signature1),
  86                       le32_to_cpu(fsinfo->signature2),
  87                       sbi->fsinfo_sector);
  88        } else {
  89                if (sbi->free_clusters != -1)
  90                        fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters);
  91                if (sbi->prev_free != -1)
  92                        fsinfo->next_cluster = cpu_to_le32(sbi->prev_free);
  93                mark_buffer_dirty(bh);
  94        }
  95        brelse(bh);
  96
  97        return 0;
  98}
  99
 100/*
 101 * fat_chain_add() adds a new cluster to the chain of clusters represented
 102 * by inode.
 103 */
 104int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
 105{
 106        struct super_block *sb = inode->i_sb;
 107        struct msdos_sb_info *sbi = MSDOS_SB(sb);
 108        int ret, new_fclus, last;
 109
 110        /*
 111         * We must locate the last cluster of the file to add this new
 112         * one (new_dclus) to the end of the link list (the FAT).
 113         */
 114        last = new_fclus = 0;
 115        if (MSDOS_I(inode)->i_start) {
 116                int fclus, dclus;
 117
 118                ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
 119                if (ret < 0)
 120                        return ret;
 121                new_fclus = fclus + 1;
 122                last = dclus;
 123        }
 124
 125        /* add new one to the last of the cluster chain */
 126        if (last) {
 127                struct fat_entry fatent;
 128
 129                fatent_init(&fatent);
 130                ret = fat_ent_read(inode, &fatent, last);
 131                if (ret >= 0) {
 132                        int wait = inode_needs_sync(inode);
 133                        ret = fat_ent_write(inode, &fatent, new_dclus, wait);
 134                        fatent_brelse(&fatent);
 135                }
 136                if (ret < 0)
 137                        return ret;
 138//              fat_cache_add(inode, new_fclus, new_dclus);
 139        } else {
 140                MSDOS_I(inode)->i_start = new_dclus;
 141                MSDOS_I(inode)->i_logstart = new_dclus;
 142                /*
 143                 * Since generic_write_sync() synchronizes regular files later,
 144                 * we sync here only directories.
 145                 */
 146                if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
 147                        ret = fat_sync_inode(inode);
 148                        if (ret)
 149                                return ret;
 150                } else
 151                        mark_inode_dirty(inode);
 152        }
 153        if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
 154                fat_fs_error(sb, "clusters badly computed (%d != %llu)",
 155                             new_fclus,
 156                             (llu)(inode->i_blocks >> (sbi->cluster_bits - 9)));
 157                fat_cache_inval_inode(inode);
 158        }
 159        inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
 160
 161        return 0;
 162}
 163
 164extern struct timezone sys_tz;
 165
 166/*
 167 * The epoch of FAT timestamp is 1980.
 168 *     :  bits :     value
 169 * date:  0 -  4: day   (1 -  31)
 170 * date:  5 -  8: month (1 -  12)
 171 * date:  9 - 15: year  (0 - 127) from 1980
 172 * time:  0 -  4: sec   (0 -  29) 2sec counts
 173 * time:  5 - 10: min   (0 -  59)
 174 * time: 11 - 15: hour  (0 -  23)
 175 */
 176#define SECS_PER_MIN    60
 177#define SECS_PER_HOUR   (60 * 60)
 178#define SECS_PER_DAY    (SECS_PER_HOUR * 24)
 179/* days between 1.1.70 and 1.1.80 (2 leap days) */
 180#define DAYS_DELTA      (365 * 10 + 2)
 181/* 120 (2100 - 1980) isn't leap year */
 182#define YEAR_2100       120
 183#define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100)
 184
 185/* Linear day numbers of the respective 1sts in non-leap years. */
 186static time_t days_in_year[] = {
 187        /* Jan  Feb  Mar  Apr  May  Jun  Jul  Aug  Sep  Oct  Nov  Dec */
 188        0,   0,  31,  59,  90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
 189};
 190
 191/* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
 192void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
 193                       __le16 __time, __le16 __date, u8 time_cs)
 194{
 195        u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
 196        time_t second, day, leap_day, month, year;
 197
 198        year  = date >> 9;
 199        month = max(1, (date >> 5) & 0xf);
 200        day   = max(1, date & 0x1f) - 1;
 201
 202        leap_day = (year + 3) / 4;
 203        if (year > YEAR_2100)           /* 2100 isn't leap year */
 204                leap_day--;
 205        if (IS_LEAP_YEAR(year) && month > 2)
 206                leap_day++;
 207
 208        second =  (time & 0x1f) << 1;
 209        second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
 210        second += (time >> 11) * SECS_PER_HOUR;
 211        second += (year * 365 + leap_day
 212                   + days_in_year[month] + day
 213                   + DAYS_DELTA) * SECS_PER_DAY;
 214
 215        if (!sbi->options.tz_utc)
 216                second += sys_tz.tz_minuteswest * SECS_PER_MIN;
 217
 218        if (time_cs) {
 219                ts->tv_sec = second + (time_cs / 100);
 220                ts->tv_nsec = (time_cs % 100) * 10000000;
 221        } else {
 222                ts->tv_sec = second;
 223                ts->tv_nsec = 0;
 224        }
 225}
 226
 227/* Convert linear UNIX date to a FAT time/date pair. */
 228void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
 229                       __le16 *time, __le16 *date, u8 *time_cs)
 230{
 231        struct tm tm;
 232        time_to_tm(ts->tv_sec, sbi->options.tz_utc ? 0 :
 233                   -sys_tz.tz_minuteswest * 60, &tm);
 234
 235        /*  FAT can only support year between 1980 to 2107 */
 236        if (tm.tm_year < 1980 - 1900) {
 237                *time = 0;
 238                *date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
 239                if (time_cs)
 240                        *time_cs = 0;
 241                return;
 242        }
 243        if (tm.tm_year > 2107 - 1900) {
 244                *time = cpu_to_le16((23 << 11) | (59 << 5) | 29);
 245                *date = cpu_to_le16((127 << 9) | (12 << 5) | 31);
 246                if (time_cs)
 247                        *time_cs = 199;
 248                return;
 249        }
 250
 251        /* from 1900 -> from 1980 */
 252        tm.tm_year -= 80;
 253        /* 0~11 -> 1~12 */
 254        tm.tm_mon++;
 255        /* 0~59 -> 0~29(2sec counts) */
 256        tm.tm_sec >>= 1;
 257
 258        *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec);
 259        *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday);
 260        if (time_cs)
 261                *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
 262}
 263EXPORT_SYMBOL_GPL(fat_time_unix2fat);
 264
 265int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
 266{
 267        int i, err = 0;
 268
 269        for (i = 0; i < nr_bhs; i++)
 270                write_dirty_buffer(bhs[i], WRITE);
 271
 272        for (i = 0; i < nr_bhs; i++) {
 273                wait_on_buffer(bhs[i]);
 274                if (!err && !buffer_uptodate(bhs[i]))
 275                        err = -EIO;
 276        }
 277        return err;
 278}
 279
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.