Commit 6bb885ec authored by Frank Sorenson's avatar Frank Sorenson Committed by Linus Torvalds
Browse files

fat: add functions to update and truncate timestamps appropriately 

Add the fat-specific inode_operation ->update_time() and
fat_truncate_time() function to truncate the inode timestamps from 1
nanosecond to the appropriate granularity.

Link: http://lkml.kernel.org/r/38af1ba3c3cf0d7381ce7b63077ef8af75901532.1538363961.git.sorenson@redhat.com


Signed-off-by: default avatarFrank Sorenson <sorenson@redhat.com>
Acked-by: default avatarOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d9f4d942

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)