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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