1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * linux/fs/fat/misc.c |
4 | * |
5 | * Written 1992,1993 by Werner Almesberger |
6 | * 22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980 |
7 | * and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru) |
8 | */ |
9 | |
10 | #include "fat.h" |
11 | #include <linux/iversion.h> |
12 | |
13 | /* |
14 | * fat_fs_error reports a file system problem that might indicate fa data |
15 | * corruption/inconsistency. Depending on 'errors' mount option the |
16 | * panic() is called, or error message is printed FAT and nothing is done, |
17 | * or filesystem is remounted read-only (default behavior). |
18 | * In case the file system is remounted read-only, it can be made writable |
19 | * again by remounting it. |
20 | */ |
21 | void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...) |
22 | { |
23 | struct fat_mount_options *opts = &MSDOS_SB(sb)->options; |
24 | va_list args; |
25 | struct va_format vaf; |
26 | |
27 | if (report) { |
28 | va_start(args, fmt); |
29 | vaf.fmt = fmt; |
30 | vaf.va = &args; |
31 | fat_msg(sb, KERN_ERR, "error, %pV" , &vaf); |
32 | va_end(args); |
33 | } |
34 | |
35 | if (opts->errors == FAT_ERRORS_PANIC) |
36 | panic(fmt: "FAT-fs (%s): fs panic from previous error\n" , sb->s_id); |
37 | else if (opts->errors == FAT_ERRORS_RO && !sb_rdonly(sb)) { |
38 | sb->s_flags |= SB_RDONLY; |
39 | fat_msg(sb, KERN_ERR, "Filesystem has been set read-only" ); |
40 | } |
41 | } |
42 | EXPORT_SYMBOL_GPL(__fat_fs_error); |
43 | |
44 | /** |
45 | * _fat_msg() - Print a preformatted FAT message based on a superblock. |
46 | * @sb: A pointer to a &struct super_block |
47 | * @level: A Kernel printk level constant |
48 | * @fmt: The printf-style format string to print. |
49 | * |
50 | * Everything that is not fat_fs_error() should be fat_msg(). |
51 | * |
52 | * fat_msg() wraps _fat_msg() for printk indexing. |
53 | */ |
54 | void _fat_msg(struct super_block *sb, const char *level, const char *fmt, ...) |
55 | { |
56 | struct va_format vaf; |
57 | va_list args; |
58 | |
59 | va_start(args, fmt); |
60 | vaf.fmt = fmt; |
61 | vaf.va = &args; |
62 | _printk(FAT_PRINTK_PREFIX "%pV\n" , level, sb->s_id, &vaf); |
63 | va_end(args); |
64 | } |
65 | |
66 | /* Flushes the number of free clusters on FAT32 */ |
67 | /* XXX: Need to write one per FSINFO block. Currently only writes 1 */ |
68 | int fat_clusters_flush(struct super_block *sb) |
69 | { |
70 | struct msdos_sb_info *sbi = MSDOS_SB(sb); |
71 | struct buffer_head *bh; |
72 | struct fat_boot_fsinfo *fsinfo; |
73 | |
74 | if (!is_fat32(sbi)) |
75 | return 0; |
76 | |
77 | bh = sb_bread(sb, block: sbi->fsinfo_sector); |
78 | if (bh == NULL) { |
79 | fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush" ); |
80 | return -EIO; |
81 | } |
82 | |
83 | fsinfo = (struct fat_boot_fsinfo *)bh->b_data; |
84 | /* Sanity check */ |
85 | if (!IS_FSINFO(fsinfo)) { |
86 | fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: " |
87 | "0x%08x, 0x%08x (sector = %lu)" , |
88 | le32_to_cpu(fsinfo->signature1), |
89 | le32_to_cpu(fsinfo->signature2), |
90 | sbi->fsinfo_sector); |
91 | } else { |
92 | if (sbi->free_clusters != -1) |
93 | fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); |
94 | if (sbi->prev_free != -1) |
95 | fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); |
96 | mark_buffer_dirty(bh); |
97 | } |
98 | brelse(bh); |
99 | |
100 | return 0; |
101 | } |
102 | |
103 | /* |
104 | * fat_chain_add() adds a new cluster to the chain of clusters represented |
105 | * by inode. |
106 | */ |
107 | int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster) |
108 | { |
109 | struct super_block *sb = inode->i_sb; |
110 | struct msdos_sb_info *sbi = MSDOS_SB(sb); |
111 | int ret, new_fclus, last; |
112 | |
113 | /* |
114 | * We must locate the last cluster of the file to add this new |
115 | * one (new_dclus) to the end of the link list (the FAT). |
116 | */ |
117 | last = new_fclus = 0; |
118 | if (MSDOS_I(inode)->i_start) { |
119 | int fclus, dclus; |
120 | |
121 | ret = fat_get_cluster(inode, FAT_ENT_EOF, fclus: &fclus, dclus: &dclus); |
122 | if (ret < 0) |
123 | return ret; |
124 | new_fclus = fclus + 1; |
125 | last = dclus; |
126 | } |
127 | |
128 | /* add new one to the last of the cluster chain */ |
129 | if (last) { |
130 | struct fat_entry fatent; |
131 | |
132 | fatent_init(fatent: &fatent); |
133 | ret = fat_ent_read(inode, fatent: &fatent, entry: last); |
134 | if (ret >= 0) { |
135 | int wait = inode_needs_sync(inode); |
136 | ret = fat_ent_write(inode, fatent: &fatent, new: new_dclus, wait); |
137 | fatent_brelse(fatent: &fatent); |
138 | } |
139 | if (ret < 0) |
140 | return ret; |
141 | /* |
142 | * FIXME:Although we can add this cache, fat_cache_add() is |
143 | * assuming to be called after linear search with fat_cache_id. |
144 | */ |
145 | // fat_cache_add(inode, new_fclus, new_dclus); |
146 | } else { |
147 | MSDOS_I(inode)->i_start = new_dclus; |
148 | MSDOS_I(inode)->i_logstart = new_dclus; |
149 | /* |
150 | * Since generic_write_sync() synchronizes regular files later, |
151 | * we sync here only directories. |
152 | */ |
153 | if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) { |
154 | ret = fat_sync_inode(inode); |
155 | if (ret) |
156 | return ret; |
157 | } else |
158 | mark_inode_dirty(inode); |
159 | } |
160 | if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) { |
161 | fat_fs_error(sb, "clusters badly computed (%d != %llu)" , |
162 | new_fclus, |
163 | (llu)(inode->i_blocks >> (sbi->cluster_bits - 9))); |
164 | fat_cache_inval_inode(inode); |
165 | } |
166 | inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9); |
167 | |
168 | return 0; |
169 | } |
170 | |
171 | /* |
172 | * The epoch of FAT timestamp is 1980. |
173 | * : bits : value |
174 | * date: 0 - 4: day (1 - 31) |
175 | * date: 5 - 8: month (1 - 12) |
176 | * date: 9 - 15: year (0 - 127) from 1980 |
177 | * time: 0 - 4: sec (0 - 29) 2sec counts |
178 | * time: 5 - 10: min (0 - 59) |
179 | * time: 11 - 15: hour (0 - 23) |
180 | */ |
181 | #define SECS_PER_MIN 60 |
182 | #define SECS_PER_HOUR (60 * 60) |
183 | #define SECS_PER_DAY (SECS_PER_HOUR * 24) |
184 | /* days between 1.1.70 and 1.1.80 (2 leap days) */ |
185 | #define DAYS_DELTA (365 * 10 + 2) |
186 | /* 120 (2100 - 1980) isn't leap year */ |
187 | #define YEAR_2100 120 |
188 | #define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100) |
189 | |
190 | /* Linear day numbers of the respective 1sts in non-leap years. */ |
191 | static long days_in_year[] = { |
192 | /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */ |
193 | 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, |
194 | }; |
195 | |
196 | static inline int fat_tz_offset(const struct msdos_sb_info *sbi) |
197 | { |
198 | return (sbi->options.tz_set ? |
199 | -sbi->options.time_offset : |
200 | sys_tz.tz_minuteswest) * SECS_PER_MIN; |
201 | } |
202 | |
203 | /* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */ |
204 | void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts, |
205 | __le16 __time, __le16 __date, u8 time_cs) |
206 | { |
207 | u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date); |
208 | time64_t second; |
209 | long day, leap_day, month, year; |
210 | |
211 | year = date >> 9; |
212 | month = max(1, (date >> 5) & 0xf); |
213 | day = max(1, date & 0x1f) - 1; |
214 | |
215 | leap_day = (year + 3) / 4; |
216 | if (year > YEAR_2100) /* 2100 isn't leap year */ |
217 | leap_day--; |
218 | if (IS_LEAP_YEAR(year) && month > 2) |
219 | leap_day++; |
220 | |
221 | second = (time & 0x1f) << 1; |
222 | second += ((time >> 5) & 0x3f) * SECS_PER_MIN; |
223 | second += (time >> 11) * SECS_PER_HOUR; |
224 | second += (time64_t)(year * 365 + leap_day |
225 | + days_in_year[month] + day |
226 | + DAYS_DELTA) * SECS_PER_DAY; |
227 | |
228 | second += fat_tz_offset(sbi); |
229 | |
230 | if (time_cs) { |
231 | ts->tv_sec = second + (time_cs / 100); |
232 | ts->tv_nsec = (time_cs % 100) * 10000000; |
233 | } else { |
234 | ts->tv_sec = second; |
235 | ts->tv_nsec = 0; |
236 | } |
237 | } |
238 | |
239 | /* Export fat_time_fat2unix() for the fat_test KUnit tests. */ |
240 | EXPORT_SYMBOL_GPL(fat_time_fat2unix); |
241 | |
242 | /* Convert linear UNIX date to a FAT time/date pair. */ |
243 | void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts, |
244 | __le16 *time, __le16 *date, u8 *time_cs) |
245 | { |
246 | struct tm tm; |
247 | time64_to_tm(totalsecs: ts->tv_sec, offset: -fat_tz_offset(sbi), result: &tm); |
248 | |
249 | /* FAT can only support year between 1980 to 2107 */ |
250 | if (tm.tm_year < 1980 - 1900) { |
251 | *time = 0; |
252 | *date = cpu_to_le16((0 << 9) | (1 << 5) | 1); |
253 | if (time_cs) |
254 | *time_cs = 0; |
255 | return; |
256 | } |
257 | if (tm.tm_year > 2107 - 1900) { |
258 | *time = cpu_to_le16((23 << 11) | (59 << 5) | 29); |
259 | *date = cpu_to_le16((127 << 9) | (12 << 5) | 31); |
260 | if (time_cs) |
261 | *time_cs = 199; |
262 | return; |
263 | } |
264 | |
265 | /* from 1900 -> from 1980 */ |
266 | tm.tm_year -= 80; |
267 | /* 0~11 -> 1~12 */ |
268 | tm.tm_mon++; |
269 | /* 0~59 -> 0~29(2sec counts) */ |
270 | tm.tm_sec >>= 1; |
271 | |
272 | *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec); |
273 | *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday); |
274 | if (time_cs) |
275 | *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000; |
276 | } |
277 | EXPORT_SYMBOL_GPL(fat_time_unix2fat); |
278 | |
279 | static inline struct timespec64 fat_timespec64_trunc_2secs(struct timespec64 ts) |
280 | { |
281 | return (struct timespec64){ ts.tv_sec & ~1ULL, 0 }; |
282 | } |
283 | |
284 | /* |
285 | * truncate atime to 24 hour granularity (00:00:00 in local timezone) |
286 | */ |
287 | struct timespec64 fat_truncate_atime(const struct msdos_sb_info *sbi, |
288 | const struct timespec64 *ts) |
289 | { |
290 | /* to localtime */ |
291 | time64_t seconds = ts->tv_sec - fat_tz_offset(sbi); |
292 | s32 remainder; |
293 | |
294 | div_s64_rem(dividend: seconds, SECS_PER_DAY, remainder: &remainder); |
295 | /* to day boundary, and back to unix time */ |
296 | seconds = seconds + fat_tz_offset(sbi) - remainder; |
297 | |
298 | return (struct timespec64){ seconds, 0 }; |
299 | } |
300 | |
301 | /* |
302 | * truncate mtime to 2 second granularity |
303 | */ |
304 | struct timespec64 fat_truncate_mtime(const struct msdos_sb_info *sbi, |
305 | const struct timespec64 *ts) |
306 | { |
307 | return fat_timespec64_trunc_2secs(ts: *ts); |
308 | } |
309 | |
310 | /* |
311 | * truncate the various times with appropriate granularity: |
312 | * all times in root node are always 0 |
313 | */ |
314 | int fat_truncate_time(struct inode *inode, struct timespec64 *now, int flags) |
315 | { |
316 | struct msdos_sb_info *sbi = MSDOS_SB(sb: inode->i_sb); |
317 | struct timespec64 ts; |
318 | |
319 | if (inode->i_ino == MSDOS_ROOT_INO) |
320 | return 0; |
321 | |
322 | if (now == NULL) { |
323 | now = &ts; |
324 | ts = current_time(inode); |
325 | } |
326 | |
327 | if (flags & S_ATIME) |
328 | inode_set_atime_to_ts(inode, ts: fat_truncate_atime(sbi, ts: now)); |
329 | /* |
330 | * ctime and mtime share the same on-disk field, and should be |
331 | * identical in memory. all mtime updates will be applied to ctime, |
332 | * but ctime updates are ignored. |
333 | */ |
334 | if (flags & S_MTIME) |
335 | inode_set_mtime_to_ts(inode, |
336 | ts: inode_set_ctime_to_ts(inode, ts: fat_truncate_mtime(sbi, ts: now))); |
337 | |
338 | return 0; |
339 | } |
340 | EXPORT_SYMBOL_GPL(fat_truncate_time); |
341 | |
342 | int fat_update_time(struct inode *inode, int flags) |
343 | { |
344 | int dirty_flags = 0; |
345 | |
346 | if (inode->i_ino == MSDOS_ROOT_INO) |
347 | return 0; |
348 | |
349 | if (flags & (S_ATIME | S_CTIME | S_MTIME)) { |
350 | fat_truncate_time(inode, NULL, flags); |
351 | if (inode->i_sb->s_flags & SB_LAZYTIME) |
352 | dirty_flags |= I_DIRTY_TIME; |
353 | else |
354 | dirty_flags |= I_DIRTY_SYNC; |
355 | } |
356 | |
357 | __mark_inode_dirty(inode, dirty_flags); |
358 | return 0; |
359 | } |
360 | EXPORT_SYMBOL_GPL(fat_update_time); |
361 | |
362 | int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs) |
363 | { |
364 | int i, err = 0; |
365 | |
366 | for (i = 0; i < nr_bhs; i++) |
367 | write_dirty_buffer(bh: bhs[i], op_flags: 0); |
368 | |
369 | for (i = 0; i < nr_bhs; i++) { |
370 | wait_on_buffer(bh: bhs[i]); |
371 | if (!err && !buffer_uptodate(bh: bhs[i])) |
372 | err = -EIO; |
373 | } |
374 | return err; |
375 | } |
376 | |