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/msdos_fs.h> 12 #include <linux/buffer_head.h> 13 14 /* 15 * fat_fs_panic reports a severe file system problem and sets the file system 16 * read-only. The file system can be made writable again by remounting it. 17 */ 18 void fat_fs_panic(struct super_block *s, const char *fmt, ...) 19 { 20 va_list args; 21 22 printk(KERN_ERR "FAT: Filesystem panic (dev %s)\n", s->s_id); 23 24 printk(KERN_ERR " "); 25 va_start(args, fmt); 26 vprintk(fmt, args); 27 va_end(args); 28 printk("\n"); 29 30 if (!(s->s_flags & MS_RDONLY)) { 31 s->s_flags |= MS_RDONLY; 32 printk(KERN_ERR " File system has been set read-only\n"); 33 } 34 } 35 36 EXPORT_SYMBOL_GPL(fat_fs_panic); 37 38 /* Flushes the number of free clusters on FAT32 */ 39 /* XXX: Need to write one per FSINFO block. Currently only writes 1 */ 40 void fat_clusters_flush(struct super_block *sb) 41 { 42 struct msdos_sb_info *sbi = MSDOS_SB(sb); 43 struct buffer_head *bh; 44 struct fat_boot_fsinfo *fsinfo; 45 46 if (sbi->fat_bits != 32) 47 return; 48 49 bh = sb_bread(sb, sbi->fsinfo_sector); 50 if (bh == NULL) { 51 printk(KERN_ERR "FAT: bread failed in fat_clusters_flush\n"); 52 return; 53 } 54 55 fsinfo = (struct fat_boot_fsinfo *)bh->b_data; 56 /* Sanity check */ 57 if (!IS_FSINFO(fsinfo)) { 58 printk(KERN_ERR "FAT: Invalid FSINFO signature: " 59 "0x%08x, 0x%08x (sector = %lu)\n", 60 le32_to_cpu(fsinfo->signature1), 61 le32_to_cpu(fsinfo->signature2), 62 sbi->fsinfo_sector); 63 } else { 64 if (sbi->free_clusters != -1) 65 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); 66 if (sbi->prev_free != -1) 67 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); 68 mark_buffer_dirty(bh); 69 } 70 brelse(bh); 71 } 72 73 /* 74 * fat_chain_add() adds a new cluster to the chain of clusters represented 75 * by inode. 76 */ 77 int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster) 78 { 79 struct super_block *sb = inode->i_sb; 80 struct msdos_sb_info *sbi = MSDOS_SB(sb); 81 int ret, new_fclus, last; 82 83 /* 84 * We must locate the last cluster of the file to add this new 85 * one (new_dclus) to the end of the link list (the FAT). 86 */ 87 last = new_fclus = 0; 88 if (MSDOS_I(inode)->i_start) { 89 int fclus, dclus; 90 91 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); 92 if (ret < 0) 93 return ret; 94 new_fclus = fclus + 1; 95 last = dclus; 96 } 97 98 /* add new one to the last of the cluster chain */ 99 if (last) { 100 struct fat_entry fatent; 101 102 fatent_init(&fatent); 103 ret = fat_ent_read(inode, &fatent, last); 104 if (ret >= 0) { 105 int wait = inode_needs_sync(inode); 106 ret = fat_ent_write(inode, &fatent, new_dclus, wait); 107 fatent_brelse(&fatent); 108 } 109 if (ret < 0) 110 return ret; 111 // fat_cache_add(inode, new_fclus, new_dclus); 112 } else { 113 MSDOS_I(inode)->i_start = new_dclus; 114 MSDOS_I(inode)->i_logstart = new_dclus; 115 /* 116 * Since generic_osync_inode() synchronize later if 117 * this is not directory, we don't here. 118 */ 119 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) { 120 ret = fat_sync_inode(inode); 121 if (ret) 122 return ret; 123 } else 124 mark_inode_dirty(inode); 125 } 126 if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) { 127 fat_fs_panic(sb, "clusters badly computed (%d != %lu)", 128 new_fclus, inode->i_blocks >> (sbi->cluster_bits - 9)); 129 fat_cache_inval_inode(inode); 130 } 131 inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9); 132 133 return 0; 134 } 135 136 extern struct timezone sys_tz; 137 138 /* Linear day numbers of the respective 1sts in non-leap years. */ 139 static int day_n[] = { 140 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */ 141 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 0 142 }; 143 144 /* Convert a MS-DOS time/date pair to a UNIX date (seconds since 1 1 70). */ 145 int date_dos2unix(unsigned short time, unsigned short date, int tz_utc) 146 { 147 int month, year, secs; 148 149 /* 150 * first subtract and mask after that... Otherwise, if 151 * date == 0, bad things happen 152 */ 153 month = ((date >> 5) - 1) & 15; 154 year = date >> 9; 155 secs = (time & 31)*2+60*((time >> 5) & 63)+(time >> 11)*3600+86400* 156 ((date & 31)-1+day_n[month]+(year/4)+year*365-((year & 3) == 0 && 157 month < 2 ? 1 : 0)+3653); 158 /* days since 1.1.70 plus 80's leap day */ 159 if (!tz_utc) 160 secs += sys_tz.tz_minuteswest*60; 161 return secs; 162 } 163 164 /* Convert linear UNIX date to a MS-DOS time/date pair. */ 165 void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date, int tz_utc) 166 { 167 int day, year, nl_day, month; 168 169 if (!tz_utc) 170 unix_date -= sys_tz.tz_minuteswest*60; 171 172 /* Jan 1 GMT 00:00:00 1980. But what about another time zone? */ 173 if (unix_date < 315532800) 174 unix_date = 315532800; 175 176 *time = cpu_to_le16((unix_date % 60)/2+(((unix_date/60) % 60) << 5)+ 177 (((unix_date/3600) % 24) << 11)); 178 day = unix_date/86400-3652; 179 year = day/365; 180 if ((year+3)/4+365*year > day) 181 year--; 182 day -= (year+3)/4+365*year; 183 if (day == 59 && !(year & 3)) { 184 nl_day = day; 185 month = 2; 186 } else { 187 nl_day = (year & 3) || day <= 59 ? day : day-1; 188 for (month = 0; month < 12; month++) { 189 if (day_n[month] > nl_day) 190 break; 191 } 192 } 193 *date = cpu_to_le16(nl_day-day_n[month-1]+1+(month << 5)+(year << 9)); 194 } 195 196 EXPORT_SYMBOL_GPL(fat_date_unix2dos); 197 198 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) 199 { 200 int i, err = 0; 201 202 ll_rw_block(SWRITE, nr_bhs, bhs); 203 for (i = 0; i < nr_bhs; i++) { 204 wait_on_buffer(bhs[i]); 205 if (buffer_eopnotsupp(bhs[i])) { 206 clear_buffer_eopnotsupp(bhs[i]); 207 err = -EOPNOTSUPP; 208 } else if (!err && !buffer_uptodate(bhs[i])) 209 err = -EIO; 210 } 211 return err; 212 } 213 214