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1e9ea7e044
This reverts commit 7ffa8f3d30.
Reverts the removal of the classic read-only ntfs driver to
serve as the base for a new read-write ntfs implementation.
If we stack changes on top of the revert patch, It will significantly
reduce the diff size, making the review easier.
This revert intentionally excludes the restoration of Kconfig and
Makefile. The Kconfig and Makefile will be added back in the final patch
of this series, enabling the driver only after all features and
improvements have been applied.
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
90 lines
2.8 KiB
C
90 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* time.h - NTFS time conversion functions. Part of the Linux-NTFS project.
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*
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* Copyright (c) 2001-2005 Anton Altaparmakov
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*/
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#ifndef _LINUX_NTFS_TIME_H
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#define _LINUX_NTFS_TIME_H
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#include <linux/time.h> /* For current_kernel_time(). */
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#include <asm/div64.h> /* For do_div(). */
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#include "endian.h"
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#define NTFS_TIME_OFFSET ((s64)(369 * 365 + 89) * 24 * 3600 * 10000000)
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/**
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* utc2ntfs - convert Linux UTC time to NTFS time
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* @ts: Linux UTC time to convert to NTFS time
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*
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* Convert the Linux UTC time @ts to its corresponding NTFS time and return
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* that in little endian format.
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*
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* Linux stores time in a struct timespec64 consisting of a time64_t tv_sec
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* and a long tv_nsec where tv_sec is the number of 1-second intervals since
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* 1st January 1970, 00:00:00 UTC and tv_nsec is the number of 1-nano-second
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* intervals since the value of tv_sec.
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*
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* NTFS uses Microsoft's standard time format which is stored in a s64 and is
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* measured as the number of 100-nano-second intervals since 1st January 1601,
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* 00:00:00 UTC.
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*/
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static inline sle64 utc2ntfs(const struct timespec64 ts)
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{
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/*
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* Convert the seconds to 100ns intervals, add the nano-seconds
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* converted to 100ns intervals, and then add the NTFS time offset.
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*/
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return cpu_to_sle64((s64)ts.tv_sec * 10000000 + ts.tv_nsec / 100 +
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NTFS_TIME_OFFSET);
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}
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/**
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* get_current_ntfs_time - get the current time in little endian NTFS format
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*
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* Get the current time from the Linux kernel, convert it to its corresponding
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* NTFS time and return that in little endian format.
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*/
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static inline sle64 get_current_ntfs_time(void)
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{
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struct timespec64 ts;
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ktime_get_coarse_real_ts64(&ts);
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return utc2ntfs(ts);
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}
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/**
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* ntfs2utc - convert NTFS time to Linux time
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* @time: NTFS time (little endian) to convert to Linux UTC
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*
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* Convert the little endian NTFS time @time to its corresponding Linux UTC
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* time and return that in cpu format.
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*
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* Linux stores time in a struct timespec64 consisting of a time64_t tv_sec
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* and a long tv_nsec where tv_sec is the number of 1-second intervals since
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* 1st January 1970, 00:00:00 UTC and tv_nsec is the number of 1-nano-second
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* intervals since the value of tv_sec.
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*
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* NTFS uses Microsoft's standard time format which is stored in a s64 and is
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* measured as the number of 100 nano-second intervals since 1st January 1601,
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* 00:00:00 UTC.
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*/
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static inline struct timespec64 ntfs2utc(const sle64 time)
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{
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struct timespec64 ts;
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/* Subtract the NTFS time offset. */
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u64 t = (u64)(sle64_to_cpu(time) - NTFS_TIME_OFFSET);
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/*
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* Convert the time to 1-second intervals and the remainder to
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* 1-nano-second intervals.
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*/
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ts.tv_nsec = do_div(t, 10000000) * 100;
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ts.tv_sec = t;
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return ts;
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}
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#endif /* _LINUX_NTFS_TIME_H */
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