LCOV - code coverage report
Current view: top level - lkbce/fs/fat - misc.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 93 131 71.0 %
Date: 2017-01-25 Functions: 5 6 83.3 %

          Line data    Source code
       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 *s, const char *fmt, ...)
      24             : {
      25        1196 :         struct fat_mount_options *opts = &MSDOS_SB(s)->options;
      26         299 :         va_list args;
      27         299 : 
      28         299 :         printk(KERN_ERR "FAT: Filesystem error (dev %s)\n", s->s_id);
      29             : 
      30         299 :         printk(KERN_ERR "    ");
      31         299 :         va_start(args, fmt);
      32         299 :         vprintk(fmt, args);
      33         299 :         va_end(args);
      34         299 :         printk("\n");
      35             : 
      36         897 :         if (opts->errors == FAT_ERRORS_PANIC)
      37         299 :                 panic("    FAT fs panic from previous error\n");
      38        1495 :         else if (opts->errors == FAT_ERRORS_RO && !(s->s_flags & MS_RDONLY)) {
      39         299 :                 s->s_flags |= MS_RDONLY;
      40         299 :                 printk(KERN_ERR "    File system has been set read-only\n");
      41             :         }
      42         299 : }
      43             : EXPORT_SYMBOL_GPL(fat_fs_error);
      44             : 
      45             : /* Flushes the number of free clusters on FAT32 */
      46             : /* XXX: Need to write one per FSINFO block.  Currently only writes 1 */
      47             : int fat_clusters_flush(struct super_block *sb)
      48             : {
      49          12 :         struct msdos_sb_info *sbi = MSDOS_SB(sb);
      50           3 :         struct buffer_head *bh;
      51           3 :         struct fat_boot_fsinfo *fsinfo;
      52           3 : 
      53           9 :         if (sbi->fat_bits != 32)
      54           3 :                 return 0;
      55             : 
      56           6 :         bh = sb_bread(sb, sbi->fsinfo_sector);
      57           6 :         if (bh == NULL) {
      58           3 :                 printk(KERN_ERR "FAT: bread failed in fat_clusters_flush\n");
      59           3 :                 return -EIO;
      60             :         }
      61             : 
      62           6 :         fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
      63             :         /* Sanity check */
      64          12 :         if (!IS_FSINFO(fsinfo)) {
      65           3 :                 printk(KERN_ERR "FAT: Invalid FSINFO signature: "
      66             :                        "0x%08x, 0x%08x (sector = %lu)\n",
      67             :                        le32_to_cpu(fsinfo->signature1),
      68             :                        le32_to_cpu(fsinfo->signature2),
      69             :                        sbi->fsinfo_sector);
      70             :         } else {
      71           6 :                 if (sbi->free_clusters != -1)
      72           3 :                         fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters);
      73           6 :                 if (sbi->prev_free != -1)
      74           3 :                         fsinfo->next_cluster = cpu_to_le32(sbi->prev_free);
      75           3 :                 mark_buffer_dirty(bh);
      76             :         }
      77           6 :         brelse(bh);
      78             : 
      79           3 :         return 0;
      80             : }
      81             : 
      82             : /*
      83             :  * fat_chain_add() adds a new cluster to the chain of clusters represented
      84             :  * by inode.
      85             :  */
      86             : int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
      87             : {
      88           0 :         struct super_block *sb = inode->i_sb;
      89           0 :         struct msdos_sb_info *sbi = MSDOS_SB(sb);
      90           0 :         int ret, new_fclus, last;
      91           0 : 
      92           0 :         /*
      93           0 :          * We must locate the last cluster of the file to add this new
      94           0 :          * one (new_dclus) to the end of the link list (the FAT).
      95           0 :          */
      96           0 :         last = new_fclus = 0;
      97           0 :         if (MSDOS_I(inode)->i_start) {
      98           0 :                 int fclus, dclus;
      99           0 : 
     100           0 :                 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
     101           0 :                 if (ret < 0)
     102           0 :                         return ret;
     103           0 :                 new_fclus = fclus + 1;
     104           0 :                 last = dclus;
     105             :         }
     106             : 
     107             :         /* add new one to the last of the cluster chain */
     108           0 :         if (last) {
     109             :                 struct fat_entry fatent;
     110             : 
     111           0 :                 fatent_init(&fatent);
     112           0 :                 ret = fat_ent_read(inode, &fatent, last);
     113           0 :                 if (ret >= 0) {
     114           0 :                         int wait = inode_needs_sync(inode);
     115           0 :                         ret = fat_ent_write(inode, &fatent, new_dclus, wait);
     116           0 :                         fatent_brelse(&fatent);
     117             :                 }
     118           0 :                 if (ret < 0)
     119           0 :                         return ret;
     120             : //              fat_cache_add(inode, new_fclus, new_dclus);
     121             :         } else {
     122           0 :                 MSDOS_I(inode)->i_start = new_dclus;
     123           0 :                 MSDOS_I(inode)->i_logstart = new_dclus;
     124             :                 /*
     125             :                  * Since generic_write_sync() synchronizes regular files later,
     126             :                  * we sync here only directories.
     127             :                  */
     128           0 :                 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
     129           0 :                         ret = fat_sync_inode(inode);
     130           0 :                         if (ret)
     131           0 :                                 return ret;
     132             :                 } else
     133           0 :                         mark_inode_dirty(inode);
     134             :         }
     135           0 :         if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
     136           0 :                 fat_fs_error(sb, "clusters badly computed (%d != %llu)",
     137             :                              new_fclus,
     138             :                              (llu)(inode->i_blocks >> (sbi->cluster_bits - 9)));
     139           0 :                 fat_cache_inval_inode(inode);
     140             :         }
     141           0 :         inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
     142             : 
     143           0 :         return 0;
     144             : }
     145             : 
     146             : extern struct timezone sys_tz;
     147             : 
     148             : /*
     149             :  * The epoch of FAT timestamp is 1980.
     150             :  *     :  bits :     value
     151             :  * date:  0 -  4: day   (1 -  31)
     152             :  * date:  5 -  8: month (1 -  12)
     153             :  * date:  9 - 15: year  (0 - 127) from 1980
     154             :  * time:  0 -  4: sec   (0 -  29) 2sec counts
     155             :  * time:  5 - 10: min   (0 -  59)
     156             :  * time: 11 - 15: hour  (0 -  23)
     157             :  */
     158             : #define SECS_PER_MIN    60
     159             : #define SECS_PER_HOUR   (60 * 60)
     160             : #define SECS_PER_DAY    (SECS_PER_HOUR * 24)
     161             : /* days between 1.1.70 and 1.1.80 (2 leap days) */
     162             : #define DAYS_DELTA      (365 * 10 + 2)
     163             : /* 120 (2100 - 1980) isn't leap year */
     164             : #define YEAR_2100       120
     165             : #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100)
     166             : 
     167             : /* Linear day numbers of the respective 1sts in non-leap years. */
     168           1 : static time_t days_in_year[] = {
     169             :         /* Jan  Feb  Mar  Apr  May  Jun  Jul  Aug  Sep  Oct  Nov  Dec */
     170             :         0,   0,  31,  59,  90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
     171             : };
     172             : 
     173             : /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
     174             : void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
     175             :                        __le16 __time, __le16 __date, u8 time_cs)
     176             : {
     177           9 :         u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
     178           3 :         time_t second, day, leap_day, month, year;
     179           3 : 
     180           6 :         year  = date >> 9;
     181          27 :         month = max(1, (date >> 5) & 0xf);
     182          27 :         day   = max(1, date & 0x1f) - 1;
     183           3 : 
     184           6 :         leap_day = (year + 3) / 4;
     185           9 :         if (year > YEAR_2100)                /* 2100 isn't leap year */
     186           6 :                 leap_day--;
     187          21 :         if (IS_LEAP_YEAR(year) && month > 2)
     188           3 :                 leap_day++;
     189             : 
     190           3 :         second =  (time & 0x1f) << 1;
     191           3 :         second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
     192           3 :         second += (time >> 11) * SECS_PER_HOUR;
     193           3 :         second += (year * 365 + leap_day
     194             :                    + days_in_year[month] + day
     195             :                    + DAYS_DELTA) * SECS_PER_DAY;
     196             : 
     197           6 :         if (!sbi->options.tz_utc)
     198           3 :                 second += sys_tz.tz_minuteswest * SECS_PER_MIN;
     199             : 
     200           6 :         if (time_cs) {
     201           3 :                 ts->tv_sec = second + (time_cs / 100);
     202           3 :                 ts->tv_nsec = (time_cs % 100) * 10000000;
     203             :         } else {
     204           3 :                 ts->tv_sec = second;
     205           3 :                 ts->tv_nsec = 0;
     206             :         }
     207           3 : }
     208             : 
     209             : /* Convert linear UNIX date to a FAT time/date pair. */
     210             : void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
     211             :                        __le16 *time, __le16 *date, u8 *time_cs)
     212             : {
     213          15 :         struct tm tm;
     214          90 :         time_to_tm(ts->tv_sec, sbi->options.tz_utc ? 0 :
     215             :                    -sys_tz.tz_minuteswest * 60, &tm);
     216             : 
     217             :         /*  FAT can only support year between 1980 to 2107 */
     218          30 :         if (tm.tm_year < 1980 - 1900) {
     219          15 :                 *time = 0;
     220          15 :                 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
     221          30 :                 if (time_cs)
     222          15 :                         *time_cs = 0;
     223          15 :                 return;
     224             :         }
     225          30 :         if (tm.tm_year > 2107 - 1900) {
     226          15 :                 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29);
     227          15 :                 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31);
     228          30 :                 if (time_cs)
     229          15 :                         *time_cs = 199;
     230          15 :                 return;
     231             :         }
     232             : 
     233             :         /* from 1900 -> from 1980 */
     234          15 :         tm.tm_year -= 80;
     235             :         /* 0~11 -> 1~12 */
     236          15 :         tm.tm_mon++;
     237             :         /* 0~59 -> 0~29(2sec counts) */
     238          15 :         tm.tm_sec >>= 1;
     239             : 
     240          15 :         *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec);
     241          15 :         *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday);
     242          30 :         if (time_cs)
     243          30 :                 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
     244          15 : }
     245             : EXPORT_SYMBOL_GPL(fat_time_unix2fat);
     246             : 
     247             : int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
     248             : {
     249          32 :         int i, err = 0;
     250          16 : 
     251          32 :         ll_rw_block(SWRITE, nr_bhs, bhs);
     252         128 :         for (i = 0; i < nr_bhs; i++) {
     253         112 :                 wait_on_buffer(bhs[i]);
     254          80 :                 if (buffer_eopnotsupp(bhs[i])) {
     255          32 :                         clear_buffer_eopnotsupp(bhs[i]);
     256          16 :                         err = -EOPNOTSUPP;
     257          96 :                 } else if (!err && !buffer_uptodate(bhs[i]))
     258          16 :                         err = -EIO;
     259             :         }
     260          16 :         return err;
     261             : }

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