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 */
__fat_fs_error(struct super_block * sb,int report,const char * fmt,...)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 fat_msg(sb, KERN_ERR, "error, %pV", &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 fat_msg(sb, KERN_ERR, "Filesystem has been set read-only");
42 }
43 }
44 EXPORT_SYMBOL_GPL(__fat_fs_error);
45
46 /**
47 * fat_msg() - print preformated FAT specific messages. Every thing what is
48 * not fat_fs_error() should be fat_msg().
49 */
fat_msg(struct super_block * sb,const char * level,const char * fmt,...)50 void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
51 {
52 struct va_format vaf;
53 va_list args;
54
55 va_start(args, fmt);
56 vaf.fmt = fmt;
57 vaf.va = &args;
58 printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf);
59 va_end(args);
60 }
61
62 /* Flushes the number of free clusters on FAT32 */
63 /* XXX: Need to write one per FSINFO block. Currently only writes 1 */
fat_clusters_flush(struct super_block * sb)64 int fat_clusters_flush(struct super_block *sb)
65 {
66 struct msdos_sb_info *sbi = MSDOS_SB(sb);
67 struct buffer_head *bh;
68 struct fat_boot_fsinfo *fsinfo;
69
70 if (sbi->fat_bits != 32)
71 return 0;
72
73 bh = sb_bread(sb, sbi->fsinfo_sector);
74 if (bh == NULL) {
75 fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush");
76 return -EIO;
77 }
78
79 fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
80 /* Sanity check */
81 if (!IS_FSINFO(fsinfo)) {
82 fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: "
83 "0x%08x, 0x%08x (sector = %lu)",
84 le32_to_cpu(fsinfo->signature1),
85 le32_to_cpu(fsinfo->signature2),
86 sbi->fsinfo_sector);
87 } else {
88 if (sbi->free_clusters != -1)
89 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters);
90 if (sbi->prev_free != -1)
91 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free);
92 mark_buffer_dirty(bh);
93 }
94 brelse(bh);
95
96 return 0;
97 }
98
99 /*
100 * fat_chain_add() adds a new cluster to the chain of clusters represented
101 * by inode.
102 */
fat_chain_add(struct inode * inode,int new_dclus,int nr_cluster)103 int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
104 {
105 struct super_block *sb = inode->i_sb;
106 struct msdos_sb_info *sbi = MSDOS_SB(sb);
107 int ret, new_fclus, last;
108
109 /*
110 * We must locate the last cluster of the file to add this new
111 * one (new_dclus) to the end of the link list (the FAT).
112 */
113 last = new_fclus = 0;
114 if (MSDOS_I(inode)->i_start) {
115 int fclus, dclus;
116
117 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
118 if (ret < 0)
119 return ret;
120 new_fclus = fclus + 1;
121 last = dclus;
122 }
123
124 /* add new one to the last of the cluster chain */
125 if (last) {
126 struct fat_entry fatent;
127
128 fatent_init(&fatent);
129 ret = fat_ent_read(inode, &fatent, last);
130 if (ret >= 0) {
131 int wait = inode_needs_sync(inode);
132 ret = fat_ent_write(inode, &fatent, new_dclus, wait);
133 fatent_brelse(&fatent);
134 }
135 if (ret < 0)
136 return ret;
137 /*
138 * FIXME:Although we can add this cache, fat_cache_add() is
139 * assuming to be called after linear search with fat_cache_id.
140 */
141 // fat_cache_add(inode, new_fclus, new_dclus);
142 } else {
143 MSDOS_I(inode)->i_start = new_dclus;
144 MSDOS_I(inode)->i_logstart = new_dclus;
145 /*
146 * Since generic_write_sync() synchronizes regular files later,
147 * we sync here only directories.
148 */
149 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
150 ret = fat_sync_inode(inode);
151 if (ret)
152 return ret;
153 } else
154 mark_inode_dirty(inode);
155 }
156 if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
157 fat_fs_error(sb, "clusters badly computed (%d != %llu)",
158 new_fclus,
159 (llu)(inode->i_blocks >> (sbi->cluster_bits - 9)));
160 fat_cache_inval_inode(inode);
161 }
162 inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
163
164 return 0;
165 }
166
167 /*
168 * The epoch of FAT timestamp is 1980.
169 * : bits : value
170 * date: 0 - 4: day (1 - 31)
171 * date: 5 - 8: month (1 - 12)
172 * date: 9 - 15: year (0 - 127) from 1980
173 * time: 0 - 4: sec (0 - 29) 2sec counts
174 * time: 5 - 10: min (0 - 59)
175 * time: 11 - 15: hour (0 - 23)
176 */
177 #define SECS_PER_MIN 60
178 #define SECS_PER_HOUR (60 * 60)
179 #define SECS_PER_DAY (SECS_PER_HOUR * 24)
180 /* days between 1.1.70 and 1.1.80 (2 leap days) */
181 #define DAYS_DELTA (365 * 10 + 2)
182 /* 120 (2100 - 1980) isn't leap year */
183 #define YEAR_2100 120
184 #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100)
185
186 /* Linear day numbers of the respective 1sts in non-leap years. */
187 static time_t days_in_year[] = {
188 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
189 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
190 };
191
192 /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
fat_time_fat2unix(struct msdos_sb_info * sbi,struct timespec * ts,__le16 __time,__le16 __date,u8 time_cs)193 void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
194 __le16 __time, __le16 __date, u8 time_cs)
195 {
196 u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
197 time_t second, day, leap_day, month, year;
198
199 year = date >> 9;
200 month = max(1, (date >> 5) & 0xf);
201 day = max(1, date & 0x1f) - 1;
202
203 leap_day = (year + 3) / 4;
204 if (year > YEAR_2100) /* 2100 isn't leap year */
205 leap_day--;
206 if (IS_LEAP_YEAR(year) && month > 2)
207 leap_day++;
208
209 second = (time & 0x1f) << 1;
210 second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
211 second += (time >> 11) * SECS_PER_HOUR;
212 second += (year * 365 + leap_day
213 + days_in_year[month] + day
214 + DAYS_DELTA) * SECS_PER_DAY;
215
216 if (!sbi->options.tz_set)
217 second += sys_tz.tz_minuteswest * SECS_PER_MIN;
218 else
219 second -= sbi->options.time_offset * SECS_PER_MIN;
220
221 if (time_cs) {
222 ts->tv_sec = second + (time_cs / 100);
223 ts->tv_nsec = (time_cs % 100) * 10000000;
224 } else {
225 ts->tv_sec = second;
226 ts->tv_nsec = 0;
227 }
228 }
229
230 /* Convert linear UNIX date to a FAT time/date pair. */
fat_time_unix2fat(struct msdos_sb_info * sbi,struct timespec * ts,__le16 * time,__le16 * date,u8 * time_cs)231 void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
232 __le16 *time, __le16 *date, u8 *time_cs)
233 {
234 struct tm tm;
235 time_to_tm(ts->tv_sec,
236 (sbi->options.tz_set ? sbi->options.time_offset :
237 -sys_tz.tz_minuteswest) * SECS_PER_MIN, &tm);
238
239 /* FAT can only support year between 1980 to 2107 */
240 if (tm.tm_year < 1980 - 1900) {
241 *time = 0;
242 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
243 if (time_cs)
244 *time_cs = 0;
245 return;
246 }
247 if (tm.tm_year > 2107 - 1900) {
248 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29);
249 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31);
250 if (time_cs)
251 *time_cs = 199;
252 return;
253 }
254
255 /* from 1900 -> from 1980 */
256 tm.tm_year -= 80;
257 /* 0~11 -> 1~12 */
258 tm.tm_mon++;
259 /* 0~59 -> 0~29(2sec counts) */
260 tm.tm_sec >>= 1;
261
262 *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec);
263 *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday);
264 if (time_cs)
265 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
266 }
267 EXPORT_SYMBOL_GPL(fat_time_unix2fat);
268
fat_sync_bhs(struct buffer_head ** bhs,int nr_bhs)269 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
270 {
271 int i, err = 0;
272
273 for (i = 0; i < nr_bhs; i++)
274 write_dirty_buffer(bhs[i], WRITE);
275
276 for (i = 0; i < nr_bhs; i++) {
277 wait_on_buffer(bhs[i]);
278 if (!err && !buffer_uptodate(bhs[i]))
279 err = -EIO;
280 }
281 return err;
282 }
283