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 "fat.h"
10
11 /*
12 * fat_fs_error reports a file system problem that might indicate fa data
13 * corruption/inconsistency. Depending on 'errors' mount option the
14 * panic() is called, or error message is printed FAT and nothing is done,
15 * or filesystem is remounted read-only (default behavior).
16 * In case the file system is remounted read-only, it can be made writable
17 * again by remounting it.
18 */
__fat_fs_error(struct super_block * sb,int report,const char * fmt,...)19 void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
20 {
21 struct fat_mount_options *opts = &MSDOS_SB(sb)->options;
22 va_list args;
23 struct va_format vaf;
24
25 if (report) {
26 va_start(args, fmt);
27 vaf.fmt = fmt;
28 vaf.va = &args;
29 fat_msg(sb, KERN_ERR, "error, %pV", &vaf);
30 va_end(args);
31 }
32
33 if (opts->errors == FAT_ERRORS_PANIC)
34 panic("FAT-fs (%s): fs panic from previous error\n", sb->s_id);
35 else if (opts->errors == FAT_ERRORS_RO && !sb_rdonly(sb)) {
36 sb->s_flags |= SB_RDONLY;
37 fat_msg(sb, KERN_ERR, "Filesystem has been set read-only");
38 }
39 }
40 EXPORT_SYMBOL_GPL(__fat_fs_error);
41
42 /**
43 * fat_msg() - print preformated FAT specific messages. Every thing what is
44 * not fat_fs_error() should be fat_msg().
45 */
fat_msg(struct super_block * sb,const char * level,const char * fmt,...)46 void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
47 {
48 struct va_format vaf;
49 va_list args;
50
51 va_start(args, fmt);
52 vaf.fmt = fmt;
53 vaf.va = &args;
54 printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf);
55 va_end(args);
56 }
57
58 /* Flushes the number of free clusters on FAT32 */
59 /* XXX: Need to write one per FSINFO block. Currently only writes 1 */
fat_clusters_flush(struct super_block * sb)60 int fat_clusters_flush(struct super_block *sb)
61 {
62 struct msdos_sb_info *sbi = MSDOS_SB(sb);
63 struct buffer_head *bh;
64 struct fat_boot_fsinfo *fsinfo;
65
66 if (sbi->fat_bits != 32)
67 return 0;
68
69 bh = sb_bread(sb, sbi->fsinfo_sector);
70 if (bh == NULL) {
71 fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush");
72 return -EIO;
73 }
74
75 fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
76 /* Sanity check */
77 if (!IS_FSINFO(fsinfo)) {
78 fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: "
79 "0x%08x, 0x%08x (sector = %lu)",
80 le32_to_cpu(fsinfo->signature1),
81 le32_to_cpu(fsinfo->signature2),
82 sbi->fsinfo_sector);
83 } else {
84 if (sbi->free_clusters != -1)
85 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters);
86 if (sbi->prev_free != -1)
87 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free);
88 mark_buffer_dirty(bh);
89 }
90 brelse(bh);
91
92 return 0;
93 }
94
95 /*
96 * fat_chain_add() adds a new cluster to the chain of clusters represented
97 * by inode.
98 */
fat_chain_add(struct inode * inode,int new_dclus,int nr_cluster)99 int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
100 {
101 struct super_block *sb = inode->i_sb;
102 struct msdos_sb_info *sbi = MSDOS_SB(sb);
103 int ret, new_fclus, last;
104
105 /*
106 * We must locate the last cluster of the file to add this new
107 * one (new_dclus) to the end of the link list (the FAT).
108 */
109 last = new_fclus = 0;
110 if (MSDOS_I(inode)->i_start) {
111 int fclus, dclus;
112
113 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
114 if (ret < 0)
115 return ret;
116 new_fclus = fclus + 1;
117 last = dclus;
118 }
119
120 /* add new one to the last of the cluster chain */
121 if (last) {
122 struct fat_entry fatent;
123
124 fatent_init(&fatent);
125 ret = fat_ent_read(inode, &fatent, last);
126 if (ret >= 0) {
127 int wait = inode_needs_sync(inode);
128 ret = fat_ent_write(inode, &fatent, new_dclus, wait);
129 fatent_brelse(&fatent);
130 }
131 if (ret < 0)
132 return ret;
133 /*
134 * FIXME:Although we can add this cache, fat_cache_add() is
135 * assuming to be called after linear search with fat_cache_id.
136 */
137 // fat_cache_add(inode, new_fclus, new_dclus);
138 } else {
139 MSDOS_I(inode)->i_start = new_dclus;
140 MSDOS_I(inode)->i_logstart = new_dclus;
141 /*
142 * Since generic_write_sync() synchronizes regular files later,
143 * we sync here only directories.
144 */
145 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
146 ret = fat_sync_inode(inode);
147 if (ret)
148 return ret;
149 } else
150 mark_inode_dirty(inode);
151 }
152 if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
153 fat_fs_error(sb, "clusters badly computed (%d != %llu)",
154 new_fclus,
155 (llu)(inode->i_blocks >> (sbi->cluster_bits - 9)));
156 fat_cache_inval_inode(inode);
157 }
158 inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
159
160 return 0;
161 }
162
163 /*
164 * The epoch of FAT timestamp is 1980.
165 * : bits : value
166 * date: 0 - 4: day (1 - 31)
167 * date: 5 - 8: month (1 - 12)
168 * date: 9 - 15: year (0 - 127) from 1980
169 * time: 0 - 4: sec (0 - 29) 2sec counts
170 * time: 5 - 10: min (0 - 59)
171 * time: 11 - 15: hour (0 - 23)
172 */
173 #define SECS_PER_MIN 60
174 #define SECS_PER_HOUR (60 * 60)
175 #define SECS_PER_DAY (SECS_PER_HOUR * 24)
176 /* days between 1.1.70 and 1.1.80 (2 leap days) */
177 #define DAYS_DELTA (365 * 10 + 2)
178 /* 120 (2100 - 1980) isn't leap year */
179 #define YEAR_2100 120
180 #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100)
181
182 /* Linear day numbers of the respective 1sts in non-leap years. */
183 static long days_in_year[] = {
184 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
185 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
186 };
187
188 /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
fat_time_fat2unix(struct msdos_sb_info * sbi,struct timespec64 * ts,__le16 __time,__le16 __date,u8 time_cs)189 void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts,
190 __le16 __time, __le16 __date, u8 time_cs)
191 {
192 u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
193 time64_t second;
194 long day, leap_day, month, year;
195
196 year = date >> 9;
197 month = max(1, (date >> 5) & 0xf);
198 day = max(1, date & 0x1f) - 1;
199
200 leap_day = (year + 3) / 4;
201 if (year > YEAR_2100) /* 2100 isn't leap year */
202 leap_day--;
203 if (IS_LEAP_YEAR(year) && month > 2)
204 leap_day++;
205
206 second = (time & 0x1f) << 1;
207 second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
208 second += (time >> 11) * SECS_PER_HOUR;
209 second += (time64_t)(year * 365 + leap_day
210 + days_in_year[month] + day
211 + DAYS_DELTA) * SECS_PER_DAY;
212
213 if (!sbi->options.tz_set)
214 second += sys_tz.tz_minuteswest * SECS_PER_MIN;
215 else
216 second -= sbi->options.time_offset * 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 timespec64 * ts,__le16 * time,__le16 * date,u8 * time_cs)228 void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,
229 __le16 *time, __le16 *date, u8 *time_cs)
230 {
231 struct tm tm;
232 time64_to_tm(ts->tv_sec,
233 (sbi->options.tz_set ? sbi->options.time_offset :
234 -sys_tz.tz_minuteswest) * SECS_PER_MIN, &tm);
235
236 /* FAT can only support year between 1980 to 2107 */
237 if (tm.tm_year < 1980 - 1900) {
238 *time = 0;
239 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
240 if (time_cs)
241 *time_cs = 0;
242 return;
243 }
244 if (tm.tm_year > 2107 - 1900) {
245 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29);
246 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31);
247 if (time_cs)
248 *time_cs = 199;
249 return;
250 }
251
252 /* from 1900 -> from 1980 */
253 tm.tm_year -= 80;
254 /* 0~11 -> 1~12 */
255 tm.tm_mon++;
256 /* 0~59 -> 0~29(2sec counts) */
257 tm.tm_sec >>= 1;
258
259 *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec);
260 *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday);
261 if (time_cs)
262 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
263 }
264 EXPORT_SYMBOL_GPL(fat_time_unix2fat);
265
fat_sync_bhs(struct buffer_head ** bhs,int nr_bhs)266 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
267 {
268 int i, err = 0;
269
270 for (i = 0; i < nr_bhs; i++)
271 write_dirty_buffer(bhs[i], 0);
272
273 for (i = 0; i < nr_bhs; i++) {
274 wait_on_buffer(bhs[i]);
275 if (!err && !buffer_uptodate(bhs[i]))
276 err = -EIO;
277 }
278 return err;
279 }
280