fs/fat/misc.c

   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  */
  23 void __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 }
  45 EXPORT_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  */
  51 void 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 */
  65 int 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  */
 104 int 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                 /*
 139                  * FIXME:Although we can add this cache, fat_cache_add() is
 140                  * assuming to be called after linear search with fat_cache_id.
 141                  */
 142 //              fat_cache_add(inode, new_fclus, new_dclus);
 143         } else {
 144                 MSDOS_I(inode)->i_start = new_dclus;
 145                 MSDOS_I(inode)->i_logstart = new_dclus;
 146                 /*
 147                  * Since generic_write_sync() synchronizes regular files later,
 148                  * we sync here only directories.
 149                  */
 150                 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
 151                         ret = fat_sync_inode(inode);
 152                         if (ret)
 153                                 return ret;
 154                 } else
 155                         mark_inode_dirty(inode);
 156         }
 157         if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
 158                 fat_fs_error(sb, "clusters badly computed (%d != %llu)",
 159                              new_fclus,
 160                              (llu)(inode->i_blocks >> (sbi->cluster_bits - 9)));
 161                 fat_cache_inval_inode(inode);
 162         }
 163         inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
 164
 165         return 0;
 166 }
 167
 168 extern struct timezone sys_tz;
 169
 170 /*
 171  * The epoch of FAT timestamp is 1980.
 172  *     :  bits :     value
 173  * date:  0 -  4: day   (1 -  31)
 174  * date:  5 -  8: month (1 -  12)
 175  * date:  9 - 15: year  (0 - 127) from 1980
 176  * time:  0 -  4: sec   (0 -  29) 2sec counts
 177  * time:  5 - 10: min   (0 -  59)
 178  * time: 11 - 15: hour  (0 -  23)
 179  */
 180 #define SECS_PER_MIN    60
 181 #define SECS_PER_HOUR   (60 * 60)
 182 #define SECS_PER_DAY    (SECS_PER_HOUR * 24)
 183 /* days between 1.1.70 and 1.1.80 (2 leap days) */
 184 #define DAYS_DELTA      (365 * 10 + 2)
 185 /* 120 (2100 - 1980) isn't leap year */
 186 #define YEAR_2100       120
 187 #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100)
 188
 189 /* Linear day numbers of the respective 1sts in non-leap years. */
 190 static time_t days_in_year[] = {
 191         /* Jan  Feb  Mar  Apr  May  Jun  Jul  Aug  Sep  Oct  Nov  Dec */
 192         0,   0,  31,  59,  90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
 193 };
 194
 195 /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
 196 void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
 197                        __le16 __time, __le16 __date, u8 time_cs)
 198 {
 199         u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
 200         time_t second, day, leap_day, month, year;
 201
 202         year  = date >> 9;
 203         month = max(1, (date >> 5) & 0xf);
 204         day   = max(1, date & 0x1f) - 1;
 205
 206         leap_day = (year + 3) / 4;
 207         if (year > YEAR_2100)           /* 2100 isn't leap year */
 208                 leap_day--;
 209         if (IS_LEAP_YEAR(year) && month > 2)
 210                 leap_day++;
 211
 212         second =  (time & 0x1f) << 1;
 213         second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
 214         second += (time >> 11) * SECS_PER_HOUR;
 215         second += (year * 365 + leap_day
 216                    + days_in_year[month] + day
 217                    + DAYS_DELTA) * SECS_PER_DAY;
 218
 219         if (!sbi->options.tz_set)
 220                 second += sys_tz.tz_minuteswest * SECS_PER_MIN;
 221         else
 222                 second -= sbi->options.time_offset * SECS_PER_MIN;
 223
 224         if (time_cs) {
 225                 ts->tv_sec = second + (time_cs / 100);
 226                 ts->tv_nsec = (time_cs % 100) * 10000000;
 227         } else {
 228                 ts->tv_sec = second;
 229                 ts->tv_nsec = 0;
 230         }
 231 }
 232
 233 /* Convert linear UNIX date to a FAT time/date pair. */
 234 void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
 235                        __le16 *time, __le16 *date, u8 *time_cs)
 236 {
 237         struct tm tm;
 238         time_to_tm(ts->tv_sec,
 239                    (sbi->options.tz_set ? sbi->options.time_offset :
 240                    -sys_tz.tz_minuteswest) * SECS_PER_MIN, &tm);
 241
 242         /*  FAT can only support year between 1980 to 2107 */
 243         if (tm.tm_year < 1980 - 1900) {
 244                 *time = 0;
 245                 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
 246                 if (time_cs)
 247                         *time_cs = 0;
 248                 return;
 249         }
 250         if (tm.tm_year > 2107 - 1900) {
 251                 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29);
 252                 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31);
 253                 if (time_cs)
 254                         *time_cs = 199;
 255                 return;
 256         }
 257
 258         /* from 1900 -> from 1980 */
 259         tm.tm_year -= 80;
 260         /* 0~11 -> 1~12 */
 261         tm.tm_mon++;
 262         /* 0~59 -> 0~29(2sec counts) */
 263         tm.tm_sec >>= 1;
 264
 265         *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec);
 266         *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday);
 267         if (time_cs)
 268                 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
 269 }
 270 EXPORT_SYMBOL_GPL(fat_time_unix2fat);
 271
 272 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
 273 {
 274         int i, err = 0;
 275
 276         for (i = 0; i < nr_bhs; i++)
 277                 write_dirty_buffer(bhs[i], WRITE);
 278
 279         for (i = 0; i < nr_bhs; i++) {
 280                 wait_on_buffer(bhs[i]);
 281                 if (!err && !buffer_uptodate(bhs[i]))
 282                         err = -EIO;
 283         }
 284         return err;
 285 }