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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363// SPDX-License-Identifier: GPL-2.0-only/* * linux/fs/fat/misc.c * * Written 1992,1993 by Werner Almesberger * 22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980 * and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru) */
#include "fat.h"#include <linux/iversion.h>
/* * fat_fs_error reports a file system problem that might indicate fa data * corruption/inconsistency. Depending on 'errors' mount option the * panic() is called, or error message is printed FAT and nothing is done, * or filesystem is remounted read-only (default behavior). * In case the file system is remounted read-only, it can be made writable * again by remounting it. */void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...){ struct fat_mount_options *opts = &MSDOS_SB(sb)->options; va_list args; struct va_format vaf;
if (report) { va_start(args, fmt); vaf.fmt = fmt; vaf.va = &args; fat_msg(sb, KERN_ERR, "error, %pV", &vaf); va_end(args); }
if (opts->errors == FAT_ERRORS_PANIC) panic("FAT-fs (%s): fs panic from previous error\n", sb->s_id); else if (opts->errors == FAT_ERRORS_RO && !sb_rdonly(sb)) { sb->s_flags |= SB_RDONLY; fat_msg(sb, KERN_ERR, "Filesystem has been set read-only"); }}EXPORT_SYMBOL_GPL(__fat_fs_error);
/** * _fat_msg() - Print a preformatted FAT message based on a superblock. * @sb: A pointer to a &struct super_block * @level: A Kernel printk level constant * @fmt: The printf-style format string to print. * * Everything that is not fat_fs_error() should be fat_msg(). * * fat_msg() wraps _fat_msg() for printk indexing. */void _fat_msg(struct super_block *sb, const char *level, const char *fmt, ...){ struct va_format vaf; va_list args;
va_start(args, fmt); vaf.fmt = fmt; vaf.va = &args; _printk(FAT_PRINTK_PREFIX "%pV\n", level, sb->s_id, &vaf); va_end(args);}
/* Flushes the number of free clusters on FAT32 *//* XXX: Need to write one per FSINFO block. Currently only writes 1 */int fat_clusters_flush(struct super_block *sb){ struct msdos_sb_info *sbi = MSDOS_SB(sb); struct buffer_head *bh; struct fat_boot_fsinfo *fsinfo;
if (!is_fat32(sbi)) return 0;
bh = sb_bread(sb, sbi->fsinfo_sector); if (bh == NULL) { fat_msg(sb, KERN_ERR, "bread failed in fat_clusters_flush"); return -EIO; }
fsinfo = (struct fat_boot_fsinfo *)bh->b_data; /* Sanity check */ if (!IS_FSINFO(fsinfo)) { fat_msg(sb, KERN_ERR, "Invalid FSINFO signature: " "0x%08x, 0x%08x (sector = %lu)", le32_to_cpu(fsinfo->signature1), le32_to_cpu(fsinfo->signature2), sbi->fsinfo_sector); } else { if (sbi->free_clusters != -1) fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); if (sbi->prev_free != -1) fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); mark_buffer_dirty(bh); } brelse(bh);
return 0;}
/* * fat_chain_add() adds a new cluster to the chain of clusters represented * by inode. */int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster){ struct super_block *sb = inode->i_sb; struct msdos_sb_info *sbi = MSDOS_SB(sb); int ret, new_fclus, last;
/* * We must locate the last cluster of the file to add this new * one (new_dclus) to the end of the link list (the FAT). */ last = new_fclus = 0; if (MSDOS_I(inode)->i_start) { int fclus, dclus;
ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus); if (ret < 0) return ret; new_fclus = fclus + 1; last = dclus; }
/* add new one to the last of the cluster chain */ if (last) { struct fat_entry fatent;
fatent_init(&fatent); ret = fat_ent_read(inode, &fatent, last); if (ret >= 0) { int wait = inode_needs_sync(inode); ret = fat_ent_write(inode, &fatent, new_dclus, wait); fatent_brelse(&fatent); } if (ret < 0) return ret; /* * FIXME:Although we can add this cache, fat_cache_add() is * assuming to be called after linear search with fat_cache_id. */// fat_cache_add(inode, new_fclus, new_dclus); } else { MSDOS_I(inode)->i_start = new_dclus; MSDOS_I(inode)->i_logstart = new_dclus; /* * Since generic_write_sync() synchronizes regular files later, * we sync here only directories. */ if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) { ret = fat_sync_inode(inode); if (ret) return ret; } else mark_inode_dirty(inode); } if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) { fat_fs_error_ratelimit( sb, "clusters badly computed (%d != %llu)", new_fclus, (llu)(inode->i_blocks >> (sbi->cluster_bits - 9))); fat_cache_inval_inode(inode); } inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
return 0;}
/* * The epoch of FAT timestamp is 1980. * : bits : value * date: 0 - 4: day (1 - 31) * date: 5 - 8: month (1 - 12) * date: 9 - 15: year (0 - 127) from 1980 * time: 0 - 4: sec (0 - 29) 2sec counts * time: 5 - 10: min (0 - 59) * time: 11 - 15: hour (0 - 23) */#define SECS_PER_MIN 60#define SECS_PER_HOUR (60 * 60)#define SECS_PER_DAY (SECS_PER_HOUR * 24)/* days between 1.1.70 and 1.1.80 (2 leap days) */#define DAYS_DELTA (365 * 10 + 2)/* 120 (2100 - 1980) isn't leap year */#define YEAR_2100 120#define IS_LEAP_YEAR(y) (!((y) & 3) && (y) != YEAR_2100)
/* Linear day numbers of the respective 1sts in non-leap years. */static long days_in_year[] = { /* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */ 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,};
static inline int fat_tz_offset(const struct msdos_sb_info *sbi){ return (sbi->options.tz_set ? -sbi->options.time_offset : sys_tz.tz_minuteswest) * SECS_PER_MIN;}
/* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec64 *ts, __le16 __time, __le16 __date, u8 time_cs){ u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date); time64_t second; long day, leap_day, month, year;
year = date >> 9; month = max(1, (date >> 5) & 0xf); day = max(1, date & 0x1f) - 1;
leap_day = (year + 3) / 4; if (year > YEAR_2100) /* 2100 isn't leap year */ leap_day--; if (IS_LEAP_YEAR(year) && month > 2) leap_day++;
second = (time & 0x1f) << 1; second += ((time >> 5) & 0x3f) * SECS_PER_MIN; second += (time >> 11) * SECS_PER_HOUR; second += (time64_t)(year * 365 + leap_day + days_in_year[month] + day + DAYS_DELTA) * SECS_PER_DAY;
second += fat_tz_offset(sbi);
if (time_cs) { ts->tv_sec = second + (time_cs / 100); ts->tv_nsec = (time_cs % 100) * 10000000; } else { ts->tv_sec = second; ts->tv_nsec = 0; }}
/* Export fat_time_fat2unix() for the fat_test KUnit tests. */EXPORT_SYMBOL_GPL(fat_time_fat2unix);
/* Convert linear UNIX date to a FAT time/date pair. */void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec64 *ts, __le16 *time, __le16 *date, u8 *time_cs){ struct tm tm; time64_to_tm(ts->tv_sec, -fat_tz_offset(sbi), &tm);
/* FAT can only support year between 1980 to 2107 */ if (tm.tm_year < 1980 - 1900) { *time = 0; *date = cpu_to_le16((0 << 9) | (1 << 5) | 1); if (time_cs) *time_cs = 0; return; } if (tm.tm_year > 2107 - 1900) { *time = cpu_to_le16((23 << 11) | (59 << 5) | 29); *date = cpu_to_le16((127 << 9) | (12 << 5) | 31); if (time_cs) *time_cs = 199; return; }
/* from 1900 -> from 1980 */ tm.tm_year -= 80; /* 0~11 -> 1~12 */ tm.tm_mon++; /* 0~59 -> 0~29(2sec counts) */ tm.tm_sec >>= 1;
*time = cpu_to_le16(tm.tm_hour << 11 | tm.tm_min << 5 | tm.tm_sec); *date = cpu_to_le16(tm.tm_year << 9 | tm.tm_mon << 5 | tm.tm_mday); if (time_cs) *time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;}EXPORT_SYMBOL_GPL(fat_time_unix2fat);
static inline struct timespec64 fat_timespec64_trunc_2secs(struct timespec64 ts){ return (struct timespec64){ ts.tv_sec & ~1ULL, 0 };}
/* * truncate atime to 24 hour granularity (00:00:00 in local timezone) */struct timespec64 fat_truncate_atime(const struct msdos_sb_info *sbi, const struct timespec64 *ts){ /* to localtime */ time64_t seconds = ts->tv_sec - fat_tz_offset(sbi); s32 remainder;
div_s64_rem(seconds, SECS_PER_DAY, &remainder); /* to day boundary, and back to unix time */ seconds = seconds + fat_tz_offset(sbi) - remainder;
return (struct timespec64){ seconds, 0 };}/* Export fat_truncate_atime() for the fat_test KUnit tests. */EXPORT_SYMBOL_GPL(fat_truncate_atime);
/* * Update the in-inode atime and/or mtime after truncating the timestamp to the * granularity. All timestamps in root inode are always 0. * * ctime and mtime share the same on-disk field, and should be identical in * memory. All mtime updates will be applied to ctime, but ctime updates are * ignored. */void fat_truncate_time(struct inode *inode, struct timespec64 *now, unsigned int flags){ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); struct timespec64 ts;
if (inode->i_ino == MSDOS_ROOT_INO) return;
if (now == NULL) { now = &ts; ts = current_time(inode); }
if (flags & FAT_UPDATE_ATIME) inode_set_atime_to_ts(inode, fat_truncate_atime(sbi, now)); if (flags & FAT_UPDATE_CMTIME) { /* truncate mtime to 2 second granularity */ struct timespec64 mtime = fat_timespec64_trunc_2secs(*now);
inode_set_mtime_to_ts(inode, mtime); inode_set_ctime_to_ts(inode, mtime); }}EXPORT_SYMBOL_GPL(fat_truncate_time);
int fat_update_time(struct inode *inode, enum fs_update_time type, unsigned int flags){ if (inode->i_ino != MSDOS_ROOT_INO) { fat_truncate_time(inode, NULL, type == FS_UPD_ATIME ? FAT_UPDATE_ATIME : FAT_UPDATE_CMTIME); __mark_inode_dirty(inode, inode_time_dirty_flag(inode)); } return 0;}EXPORT_SYMBOL_GPL(fat_update_time);
int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs){ int i, err = 0;
for (i = 0; i < nr_bhs; i++) write_dirty_buffer(bhs[i], 0);
for (i = 0; i < nr_bhs; i++) { wait_on_buffer(bhs[i]); if (!err && !buffer_uptodate(bhs[i])) err = -EIO; } return err;}