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 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 */
fat_msg(struct super_block * sb,const char * level,const char * fmt,...)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 */
fat_clusters_flush(struct super_block * sb)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 */
fat_chain_add(struct inode * inode,int new_dclus,int nr_cluster)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 // 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
164 extern 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. */
186 static 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). */
fat_time_fat2unix(struct msdos_sb_info * sbi,struct timespec * ts,__le16 __time,__le16 __date,u8 time_cs)192 void 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. */
fat_time_unix2fat(struct msdos_sb_info * sbi,struct timespec * ts,__le16 * time,__le16 * date,u8 * time_cs)228 void 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 }
263 EXPORT_SYMBOL_GPL(fat_time_unix2fat);
264
fat_sync_bhs(struct buffer_head ** bhs,int nr_bhs)265 int 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