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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
OGAWA Hirofumi9e975da2008-11-06 12:53:46 -08009#include "fat.h"
Frank Sorenson6bb885e2018-10-30 15:06:53 -070010#include <linux/iversion.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011
12/*
Denis Karpov85c78592009-06-04 02:34:22 +090013 * fat_fs_error reports a file system problem that might indicate fa data
14 * corruption/inconsistency. Depending on 'errors' mount option the
15 * panic() is called, or error message is printed FAT and nothing is done,
16 * or filesystem is remounted read-only (default behavior).
17 * In case the file system is remounted read-only, it can be made writable
18 * again by remounting it.
Linus Torvalds1da177e2005-04-16 15:20:36 -070019 */
Alexey Fisher2c8a5ff2011-04-12 21:08:38 +090020void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
Linus Torvalds1da177e2005-04-16 15:20:36 -070021{
Alexey Fisher2c8a5ff2011-04-12 21:08:38 +090022 struct fat_mount_options *opts = &MSDOS_SB(sb)->options;
Linus Torvalds1da177e2005-04-16 15:20:36 -070023 va_list args;
Alexey Fisher2c8a5ff2011-04-12 21:08:38 +090024 struct va_format vaf;
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
OGAWA Hirofumiaaa04b42010-05-24 14:33:12 -070026 if (report) {
OGAWA Hirofumiaaa04b42010-05-24 14:33:12 -070027 va_start(args, fmt);
Alexey Fisher2c8a5ff2011-04-12 21:08:38 +090028 vaf.fmt = fmt;
29 vaf.va = &args;
Gu Zhenge68e96d2013-07-03 15:08:08 -070030 fat_msg(sb, KERN_ERR, "error, %pV", &vaf);
OGAWA Hirofumiaaa04b42010-05-24 14:33:12 -070031 va_end(args);
OGAWA Hirofumiaaa04b42010-05-24 14:33:12 -070032 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
Denis Karpov85c78592009-06-04 02:34:22 +090034 if (opts->errors == FAT_ERRORS_PANIC)
Alexey Fisher2c8a5ff2011-04-12 21:08:38 +090035 panic("FAT-fs (%s): fs panic from previous error\n", sb->s_id);
David Howellsbc98a422017-07-17 08:45:34 +010036 else if (opts->errors == FAT_ERRORS_RO && !sb_rdonly(sb)) {
Linus Torvalds1751e8a2017-11-27 13:05:09 -080037 sb->s_flags |= SB_RDONLY;
Gu Zhenge68e96d2013-07-03 15:08:08 -070038 fat_msg(sb, KERN_ERR, "Filesystem has been set read-only");
Linus Torvalds1da177e2005-04-16 15:20:36 -070039 }
40}
OGAWA Hirofumiaaa04b42010-05-24 14:33:12 -070041EXPORT_SYMBOL_GPL(__fat_fs_error);
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
Alexey Fisher81ac21d2011-04-12 21:08:38 +090043/**
44 * fat_msg() - print preformated FAT specific messages. Every thing what is
45 * not fat_fs_error() should be fat_msg().
46 */
47void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...)
48{
49 struct va_format vaf;
50 va_list args;
51
52 va_start(args, fmt);
53 vaf.fmt = fmt;
54 vaf.va = &args;
55 printk("%sFAT-fs (%s): %pV\n", level, sb->s_id, &vaf);
56 va_end(args);
57}
58
Linus Torvalds1da177e2005-04-16 15:20:36 -070059/* Flushes the number of free clusters on FAT32 */
60/* XXX: Need to write one per FSINFO block. Currently only writes 1 */
OGAWA Hirofumied248b22009-09-20 01:31:58 +090061int fat_clusters_flush(struct super_block *sb)
Linus Torvalds1da177e2005-04-16 15:20:36 -070062{
63 struct msdos_sb_info *sbi = MSDOS_SB(sb);
64 struct buffer_head *bh;
65 struct fat_boot_fsinfo *fsinfo;
66
Carmeli Tamir306790f2019-01-03 15:28:00 -080067 if (!is_fat32(sbi))
OGAWA Hirofumied248b22009-09-20 01:31:58 +090068 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070069
70 bh = sb_bread(sb, sbi->fsinfo_sector);
71 if (bh == NULL) {
Alexey Fisher869f58c2011-04-12 21:08:38 +090072 fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush");
OGAWA Hirofumied248b22009-09-20 01:31:58 +090073 return -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 }
75
76 fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
77 /* Sanity check */
78 if (!IS_FSINFO(fsinfo)) {
Alexey Fisher869f58c2011-04-12 21:08:38 +090079 fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: "
80 "0x%08x, 0x%08x (sector = %lu)",
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 le32_to_cpu(fsinfo->signature1),
82 le32_to_cpu(fsinfo->signature2),
83 sbi->fsinfo_sector);
84 } else {
85 if (sbi->free_clusters != -1)
86 fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters);
87 if (sbi->prev_free != -1)
88 fsinfo->next_cluster = cpu_to_le32(sbi->prev_free);
89 mark_buffer_dirty(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 }
91 brelse(bh);
OGAWA Hirofumied248b22009-09-20 01:31:58 +090092
93 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070094}
95
96/*
97 * fat_chain_add() adds a new cluster to the chain of clusters represented
98 * by inode.
99 */
100int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
101{
102 struct super_block *sb = inode->i_sb;
103 struct msdos_sb_info *sbi = MSDOS_SB(sb);
104 int ret, new_fclus, last;
105
106 /*
107 * We must locate the last cluster of the file to add this new
108 * one (new_dclus) to the end of the link list (the FAT).
109 */
110 last = new_fclus = 0;
111 if (MSDOS_I(inode)->i_start) {
112 int fclus, dclus;
113
114 ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
115 if (ret < 0)
116 return ret;
117 new_fclus = fclus + 1;
118 last = dclus;
119 }
120
121 /* add new one to the last of the cluster chain */
122 if (last) {
123 struct fat_entry fatent;
124
125 fatent_init(&fatent);
126 ret = fat_ent_read(inode, &fatent, last);
127 if (ret >= 0) {
128 int wait = inode_needs_sync(inode);
129 ret = fat_ent_write(inode, &fatent, new_dclus, wait);
130 fatent_brelse(&fatent);
131 }
132 if (ret < 0)
133 return ret;
Ravishankar Nc39540c2012-12-20 15:05:46 -0800134 /*
135 * FIXME:Although we can add this cache, fat_cache_add() is
136 * assuming to be called after linear search with fat_cache_id.
137 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138// 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 /*
Jan Kara2f3d6752009-08-17 17:00:02 +0200143 * Since generic_write_sync() synchronizes regular files later,
144 * we sync here only directories.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 */
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))) {
Denis Karpov85c78592009-06-04 02:34:22 +0900154 fat_fs_error(sb, "clusters badly computed (%d != %llu)",
OGAWA Hirofumic3302932008-11-06 12:53:58 -0800155 new_fclus,
156 (llu)(inode->i_blocks >> (sbi->cluster_bits - 9)));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 fat_cache_inval_inode(inode);
158 }
159 inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
160
161 return 0;
162}
163
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800164/*
165 * The epoch of FAT timestamp is 1980.
166 * : bits : value
167 * date: 0 - 4: day (1 - 31)
168 * date: 5 - 8: month (1 - 12)
169 * date: 9 - 15: year (0 - 127) from 1980
170 * time: 0 - 4: sec (0 - 29) 2sec counts
171 * time: 5 - 10: min (0 - 59)
172 * time: 11 - 15: hour (0 - 23)
173 */
174#define SECS_PER_MIN 60
175#define SECS_PER_HOUR (60 * 60)
176#define SECS_PER_DAY (SECS_PER_HOUR * 24)
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800177/* days between 1.1.70 and 1.1.80 (2 leap days) */
178#define DAYS_DELTA (365 * 10 + 2)
179/* 120 (2100 - 1980) isn't leap year */
180#define YEAR_2100 120
181#define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100)
182
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183/* Linear day numbers of the respective 1sts in non-leap years. */
Arnd Bergmannf4234202018-08-21 21:59:48 -0700184static long days_in_year[] = {
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800185 /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
186 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187};
188
Frank Sorensond9f4d942018-10-30 15:06:50 -0700189static inline int fat_tz_offset(struct msdos_sb_info *sbi)
190{
191 return (sbi->options.tz_set ?
192 -sbi->options.time_offset :
193 sys_tz.tz_minuteswest) * SECS_PER_MIN;
194}
195
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800196/* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
Arnd Bergmannf4234202018-08-21 21:59:48 -0700197void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts,
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800198 __le16 __time, __le16 __date, u8 time_cs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199{
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800200 u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
Arnd Bergmannf4234202018-08-21 21:59:48 -0700201 time64_t second;
202 long day, leap_day, month, year;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800204 year = date >> 9;
205 month = max(1, (date >> 5) & 0xf);
206 day = max(1, date & 0x1f) - 1;
207
208 leap_day = (year + 3) / 4;
209 if (year > YEAR_2100) /* 2100 isn't leap year */
210 leap_day--;
211 if (IS_LEAP_YEAR(year) && month > 2)
212 leap_day++;
213
214 second = (time & 0x1f) << 1;
215 second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
216 second += (time >> 11) * SECS_PER_HOUR;
Arnd Bergmannf4234202018-08-21 21:59:48 -0700217 second += (time64_t)(year * 365 + leap_day
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800218 + days_in_year[month] + day
219 + DAYS_DELTA) * SECS_PER_DAY;
220
Frank Sorensond9f4d942018-10-30 15:06:50 -0700221 second += fat_tz_offset(sbi);
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800222
223 if (time_cs) {
224 ts->tv_sec = second + (time_cs / 100);
225 ts->tv_nsec = (time_cs % 100) * 10000000;
226 } else {
227 ts->tv_sec = second;
228 ts->tv_nsec = 0;
229 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230}
231
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800232/* Convert linear UNIX date to a FAT time/date pair. */
Arnd Bergmannf4234202018-08-21 21:59:48 -0700233void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts,
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800234 __le16 *time, __le16 *date, u8 *time_cs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235{
Zhaolei1d81a182009-12-15 16:46:57 -0800236 struct tm tm;
Frank Sorensond9f4d942018-10-30 15:06:50 -0700237 time64_to_tm(ts->tv_sec, -fat_tz_offset(sbi), &tm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238
Zhaolei1d81a182009-12-15 16:46:57 -0800239 /* FAT can only support year between 1980 to 2107 */
240 if (tm.tm_year < 1980 - 1900) {
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800241 *time = 0;
242 *date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
243 if (time_cs)
244 *time_cs = 0;
245 return;
246 }
Zhaolei1d81a182009-12-15 16:46:57 -0800247 if (tm.tm_year > 2107 - 1900) {
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800248 *time = cpu_to_le16((23 << 11) | (59 << 5) | 29);
249 *date = cpu_to_le16((127 << 9) | (12 << 5) | 31);
250 if (time_cs)
251 *time_cs = 199;
252 return;
253 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254
Zhaolei1d81a182009-12-15 16:46:57 -0800255 /* from 1900 -> from 1980 */
256 tm.tm_year -= 80;
257 /* 0~11 -> 1~12 */
258 tm.tm_mon++;
259 /* 0~59 -> 0~29(2sec counts) */
260 tm.tm_sec >>= 1;
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800261
Zhaolei1d81a182009-12-15 16:46:57 -0800262 *time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec);
263 *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday);
OGAWA Hirofumi7decd1c2008-11-06 12:53:47 -0800264 if (time_cs)
265 *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
266}
267EXPORT_SYMBOL_GPL(fat_time_unix2fat);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268
Frank Sorenson6bb885e2018-10-30 15:06:53 -0700269static inline struct timespec64 fat_timespec64_trunc_2secs(struct timespec64 ts)
270{
271 return (struct timespec64){ ts.tv_sec & ~1ULL, 0 };
272}
273/*
274 * truncate the various times with appropriate granularity:
275 * root inode:
276 * all times always 0
277 * all other inodes:
278 * mtime - 2 seconds
279 * ctime
280 * msdos - 2 seconds
281 * vfat - 10 milliseconds
282 * atime - 24 hours (00:00:00 in local timezone)
283 */
284int fat_truncate_time(struct inode *inode, struct timespec64 *now, int flags)
285{
286 struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
287 struct timespec64 ts;
288
289 if (inode->i_ino == MSDOS_ROOT_INO)
290 return 0;
291
292 if (now == NULL) {
293 now = &ts;
294 ts = current_time(inode);
295 }
296
297 if (flags & S_ATIME) {
298 /* to localtime */
299 time64_t seconds = now->tv_sec - fat_tz_offset(sbi);
300 s32 remainder;
301
302 div_s64_rem(seconds, SECS_PER_DAY, &remainder);
303 /* to day boundary, and back to unix time */
304 seconds = seconds + fat_tz_offset(sbi) - remainder;
305
306 inode->i_atime = (struct timespec64){ seconds, 0 };
307 }
308 if (flags & S_CTIME) {
309 if (sbi->options.isvfat)
310 inode->i_ctime = timespec64_trunc(*now, 10000000);
311 else
312 inode->i_ctime = fat_timespec64_trunc_2secs(*now);
313 }
314 if (flags & S_MTIME)
315 inode->i_mtime = fat_timespec64_trunc_2secs(*now);
316
317 return 0;
318}
319EXPORT_SYMBOL_GPL(fat_truncate_time);
320
321int fat_update_time(struct inode *inode, struct timespec64 *now, int flags)
322{
323 int iflags = I_DIRTY_TIME;
324 bool dirty = false;
325
326 if (inode->i_ino == MSDOS_ROOT_INO)
327 return 0;
328
329 fat_truncate_time(inode, now, flags);
330 if (flags & S_VERSION)
331 dirty = inode_maybe_inc_iversion(inode, false);
332 if ((flags & (S_ATIME | S_CTIME | S_MTIME)) &&
333 !(inode->i_sb->s_flags & SB_LAZYTIME))
334 dirty = true;
335
336 if (dirty)
337 iflags |= I_DIRTY_SYNC;
338 __mark_inode_dirty(inode, iflags);
339 return 0;
340}
341EXPORT_SYMBOL_GPL(fat_update_time);
342
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
344{
OGAWA Hirofumi5b002262006-02-03 03:04:42 -0800345 int i, err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346
Christoph Hellwig9cb569d2010-08-11 17:06:24 +0200347 for (i = 0; i < nr_bhs; i++)
Mike Christie2a222ca2016-06-05 14:31:43 -0500348 write_dirty_buffer(bhs[i], 0);
Christoph Hellwig9cb569d2010-08-11 17:06:24 +0200349
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 for (i = 0; i < nr_bhs; i++) {
351 wait_on_buffer(bhs[i]);
Christoph Hellwig0edd55f2010-08-18 05:29:23 -0400352 if (!err && !buffer_uptodate(bhs[i]))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 err = -EIO;
354 }
355 return err;
356}