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