fat: add functions to update and truncate timestamps appropriately (6bb885ec) · Commits · 戴 / test

fs/fat/fat.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -416,6 +416,10 @@ extern void fat_time_fat2unix(struct msdos_sb_info sbi, struct timespec64 ts,
		__le16 __time, __le16 __date, u8 time_cs);
		extern void fat_time_unix2fat(struct msdos_sb_info sbi, struct timespec64 ts,
		__le16 time, __le16 date, u8 *time_cs);
		extern int fat_truncate_time(struct inode inode, struct timespec64 now,
		int flags);
		extern int fat_update_time(struct inode inode, struct timespec64 now,
		int flags);
		extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);

		int fat_cache_init(void);

fs/fat/file.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -552,4 +552,5 @@ EXPORT_SYMBOL_GPL(fat_setattr);
		const struct inode_operations fat_file_inode_operations = {
		.setattr = fat_setattr,
		.getattr = fat_getattr,
		.update_time = fat_update_time,
		};

fs/fat/inode.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -1626,6 +1626,11 @@ int fat_fill_super(struct super_block sb, void data, int silent, int isvfat,
		sb->s_magic = MSDOS_SUPER_MAGIC;
		sb->s_op = &fat_sops;
		sb->s_export_op = &fat_export_ops;
		/*
		* fat timestamps are complex and truncated by fat itself, so
		* we set 1 here to be fast
		*/
		sb->s_time_gran = 1;
		mutex_init(&sbi->nfs_build_inode_lock);
		ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
		DEFAULT_RATELIMIT_BURST);

fs/fat/misc.c

+75 −0

Original line number	Diff line number	Diff line
		@@ -7,6 +7,7 @@
		*/

		#include "fat.h"
		#include <linux/iversion.h>

		/*
		* fat_fs_error reports a file system problem that might indicate fa data
		@@ -265,6 +266,80 @@ void fat_time_unix2fat(struct msdos_sb_info sbi, struct timespec64 ts,
		}
		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 the various times with appropriate granularity:
		* root inode:
		* all times always 0
		* all other inodes:
		* mtime - 2 seconds
		* ctime
		* msdos - 2 seconds
		* vfat - 10 milliseconds
		* atime - 24 hours (00:00:00 in local timezone)
		*/
		int fat_truncate_time(struct inode inode, struct timespec64 now, int flags)
		{
		struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
		struct timespec64 ts;

		if (inode->i_ino == MSDOS_ROOT_INO)
		return 0;

		if (now == NULL) {
		now = &ts;
		ts = current_time(inode);
		}

		if (flags & S_ATIME) {
		/* to localtime */
		time64_t seconds = now->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;

		inode->i_atime = (struct timespec64){ seconds, 0 };
		}
		if (flags & S_CTIME) {
		if (sbi->options.isvfat)
		inode->i_ctime = timespec64_trunc(*now, 10000000);
		else
		inode->i_ctime = fat_timespec64_trunc_2secs(*now);
		}
		if (flags & S_MTIME)
		inode->i_mtime = fat_timespec64_trunc_2secs(*now);

		return 0;
		}
		EXPORT_SYMBOL_GPL(fat_truncate_time);

		int fat_update_time(struct inode inode, struct timespec64 now, int flags)
		{
		int iflags = I_DIRTY_TIME;
		bool dirty = false;

		if (inode->i_ino == MSDOS_ROOT_INO)
		return 0;

		fat_truncate_time(inode, now, flags);
		if (flags & S_VERSION)
		dirty = inode_maybe_inc_iversion(inode, false);
		if ((flags & (S_ATIME \| S_CTIME \| S_MTIME)) &&
		!(inode->i_sb->s_flags & SB_LAZYTIME))
		dirty = true;

		if (dirty)
		iflags \|= I_DIRTY_SYNC;
		__mark_inode_dirty(inode, iflags);
		return 0;
		}
		EXPORT_SYMBOL_GPL(fat_update_time);

		int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
		{
		int i, err = 0;

fs/fat/namei_msdos.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -637,6 +637,7 @@ static const struct inode_operations msdos_dir_inode_operations = {
		.rename = msdos_rename,
		.setattr = fat_setattr,
		.getattr = fat_getattr,
		.update_time = fat_update_time,
		};

		static void setup(struct super_block *sb)

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