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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 | struct fat_mount_options *opts = &MSDOS_SB(s)->options; |
26 | va_list args; |
27 | |
28 | printk(KERN_ERR "FAT: Filesystem error (dev %s)\n", s->s_id); |
29 | |
30 | printk(KERN_ERR " "); |
31 | va_start(args, fmt); |
32 | vprintk(fmt, args); |
33 | va_end(args); |
34 | printk("\n"); |
35 | |
36 | if (opts->errors == FAT_ERRORS_PANIC) |
37 | panic(" FAT fs panic from previous error\n"); |
38 | else if (opts->errors == FAT_ERRORS_RO && !(s->s_flags & MS_RDONLY)) { |
39 | s->s_flags |= MS_RDONLY; |
40 | printk(KERN_ERR " File system has been set read-only\n"); |
41 | } |
42 | } |
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 | struct msdos_sb_info *sbi = MSDOS_SB(sb); |
50 | struct buffer_head *bh; |
51 | struct fat_boot_fsinfo *fsinfo; |
52 | |
53 | if (sbi->fat_bits != 32) |
54 | return 0; |
55 | |
56 | bh = sb_bread(sb, sbi->fsinfo_sector); |
57 | if (bh == NULL) { |
58 | printk(KERN_ERR "FAT: bread failed in fat_clusters_flush\n"); |
59 | return -EIO; |
60 | } |
61 | |
62 | fsinfo = (struct fat_boot_fsinfo *)bh->b_data; |
63 | /* Sanity check */ |
64 | if (!IS_FSINFO(fsinfo)) { |
65 | 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 | if (sbi->free_clusters != -1) |
72 | fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); |
73 | if (sbi->prev_free != -1) |
74 | fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); |
75 | mark_buffer_dirty(bh); |
76 | } |
77 | brelse(bh); |
78 | |
79 | 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 | struct super_block *sb = inode->i_sb; |
89 | struct msdos_sb_info *sbi = MSDOS_SB(sb); |
90 | int ret, new_fclus, last; |
91 | |
92 | /* |
93 | * We must locate the last cluster of the file to add this new |
94 | * one (new_dclus) to the end of the link list (the FAT). |
95 | */ |
96 | last = new_fclus = 0; |
97 | if (MSDOS_I(inode)->i_start) { |
98 | int fclus, dclus; |
99 | |
100 | ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); |
101 | if (ret < 0) |
102 | return ret; |
103 | new_fclus = fclus + 1; |
104 | last = dclus; |
105 | } |
106 | |
107 | /* add new one to the last of the cluster chain */ |
108 | if (last) { |
109 | struct fat_entry fatent; |
110 | |
111 | fatent_init(&fatent); |
112 | ret = fat_ent_read(inode, &fatent, last); |
113 | if (ret >= 0) { |
114 | int wait = inode_needs_sync(inode); |
115 | ret = fat_ent_write(inode, &fatent, new_dclus, wait); |
116 | fatent_brelse(&fatent); |
117 | } |
118 | if (ret < 0) |
119 | return ret; |
120 | // fat_cache_add(inode, new_fclus, new_dclus); |
121 | } else { |
122 | MSDOS_I(inode)->i_start = new_dclus; |
123 | 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 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) { |
129 | ret = fat_sync_inode(inode); |
130 | if (ret) |
131 | return ret; |
132 | } else |
133 | mark_inode_dirty(inode); |
134 | } |
135 | if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) { |
136 | fat_fs_error(sb, "clusters badly computed (%d != %llu)", |
137 | new_fclus, |
138 | (llu)(inode->i_blocks >> (sbi->cluster_bits - 9))); |
139 | fat_cache_inval_inode(inode); |
140 | } |
141 | inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9); |
142 | |
143 | 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 | 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 | u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date); |
178 | time_t second, day, leap_day, month, year; |
179 | |
180 | year = date >> 9; |
181 | month = max(1, (date >> 5) & 0xf); |
182 | day = max(1, date & 0x1f) - 1; |
183 | |
184 | leap_day = (year + 3) / 4; |
185 | if (year > YEAR_2100) /* 2100 isn't leap year */ |
186 | leap_day--; |
187 | if (IS_LEAP_YEAR(year) && month > 2) |
188 | leap_day++; |
189 | |
190 | second = (time & 0x1f) << 1; |
191 | second += ((time >> 5) & 0x3f) * SECS_PER_MIN; |
192 | second += (time >> 11) * SECS_PER_HOUR; |
193 | second += (year * 365 + leap_day |
194 | + days_in_year[month] + day |
195 | + DAYS_DELTA) * SECS_PER_DAY; |
196 | |
197 | if (!sbi->options.tz_utc) |
198 | second += sys_tz.tz_minuteswest * SECS_PER_MIN; |
199 | |
200 | if (time_cs) { |
201 | ts->tv_sec = second + (time_cs / 100); |
202 | ts->tv_nsec = (time_cs % 100) * 10000000; |
203 | } else { |
204 | ts->tv_sec = second; |
205 | ts->tv_nsec = 0; |
206 | } |
207 | } |
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 | struct tm tm; |
214 | 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 | if (tm.tm_year < 1980 - 1900) { |
219 | *time = 0; |
220 | *date = cpu_to_le16((0 << 9) | (1 << 5) | 1); |
221 | if (time_cs) |
222 | *time_cs = 0; |
223 | return; |
224 | } |
225 | if (tm.tm_year > 2107 - 1900) { |
226 | *time = cpu_to_le16((23 << 11) | (59 << 5) | 29); |
227 | *date = cpu_to_le16((127 << 9) | (12 << 5) | 31); |
228 | if (time_cs) |
229 | *time_cs = 199; |
230 | return; |
231 | } |
232 | |
233 | /* from 1900 -> from 1980 */ |
234 | tm.tm_year -= 80; |
235 | /* 0~11 -> 1~12 */ |
236 | tm.tm_mon++; |
237 | /* 0~59 -> 0~29(2sec counts) */ |
238 | tm.tm_sec >>= 1; |
239 | |
240 | *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec); |
241 | *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday); |
242 | if (time_cs) |
243 | *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000; |
244 | } |
245 | EXPORT_SYMBOL_GPL(fat_time_unix2fat); |
246 | |
247 | int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) |
248 | { |
249 | int i, err = 0; |
250 | |
251 | ll_rw_block(SWRITE, nr_bhs, bhs); |
252 | for (i = 0; i < nr_bhs; i++) { |
253 | wait_on_buffer(bhs[i]); |
254 | if (buffer_eopnotsupp(bhs[i])) { |
255 | clear_buffer_eopnotsupp(bhs[i]); |
256 | err = -EOPNOTSUPP; |
257 | } else if (!err && !buffer_uptodate(bhs[i])) |
258 | err = -EIO; |
259 | } |
260 | return err; |
261 | } |
262 |
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