Re: [PATCH] nilfs2: use time64_t internally

From: Ryusuke Konishi
Date: Mon Jan 22 2018 - 19:31:32 EST


2018-01-23 6:10 GMT+09:00 Arnd Bergmann <arnd@xxxxxxxx>:
> The superblock and segment timestamps are used only internally in nilfs2
> and can be read out using sysfs. Since we are using the old 'get_seconds()'
> interface and store the data as timestamps, the behavior differs slightly
> between 64-bit and 32-bit kernels, the latter will show incorrect timestamps
> after 2038 in sysfs, and presumably fail completely in 2106 as comparisons
> go wrong.
>
> This changes nilfs2 to use time64_t with ktime_get_real_seconds() to handle
> timestamps, making the behavior consistent and correct on both 32-bit
> and 64-bit machines.
>
> The on-disk format already uses 64-bit timestamps, so nothing changes
> there.
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Thank you for this patch.

Acked-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>


> ---
> fs/nilfs2/segbuf.c | 2 +-
> fs/nilfs2/segbuf.h | 4 ++--
> fs/nilfs2/segment.c | 2 +-
> fs/nilfs2/segment.h | 2 +-
> fs/nilfs2/sufile.c | 2 +-
> fs/nilfs2/sufile.h | 2 +-
> fs/nilfs2/super.c | 4 ++--
> fs/nilfs2/sysfs.c | 21 ++++++++++-----------
> fs/nilfs2/the_nilfs.h | 8 ++++----
> 9 files changed, 23 insertions(+), 24 deletions(-)
>
> diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
> index 6c5009cc4e6f..68cb9e4740b4 100644
> --- a/fs/nilfs2/segbuf.c
> +++ b/fs/nilfs2/segbuf.c
> @@ -130,7 +130,7 @@ int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *segbuf,
> }
>
> int nilfs_segbuf_reset(struct nilfs_segment_buffer *segbuf, unsigned int flags,
> - time_t ctime, __u64 cno)
> + time64_t ctime, __u64 cno)
> {
> int err;
>
> diff --git a/fs/nilfs2/segbuf.h b/fs/nilfs2/segbuf.h
> index 7bbccc099709..10e16935fff6 100644
> --- a/fs/nilfs2/segbuf.h
> +++ b/fs/nilfs2/segbuf.h
> @@ -46,7 +46,7 @@ struct nilfs_segsum_info {
> unsigned long nfileblk;
> u64 seg_seq;
> __u64 cno;
> - time_t ctime;
> + time64_t ctime;
> sector_t next;
> };
>
> @@ -120,7 +120,7 @@ void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
> struct nilfs_segment_buffer *prev);
> void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64,
> struct the_nilfs *);
> -int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned int, time_t,
> +int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned int, time64_t,
> __u64);
> int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *);
> int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *,
> diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
> index 9f3ffba41533..0953635e7d48 100644
> --- a/fs/nilfs2/segment.c
> +++ b/fs/nilfs2/segment.c
> @@ -2040,7 +2040,7 @@ static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
> goto out;
>
> /* Update time stamp */
> - sci->sc_seg_ctime = get_seconds();
> + sci->sc_seg_ctime = ktime_get_real_seconds();
>
> err = nilfs_segctor_collect(sci, nilfs, mode);
> if (unlikely(err))
> diff --git a/fs/nilfs2/segment.h b/fs/nilfs2/segment.h
> index 84084a4d9b3e..04634e3e3d58 100644
> --- a/fs/nilfs2/segment.h
> +++ b/fs/nilfs2/segment.h
> @@ -157,7 +157,7 @@ struct nilfs_sc_info {
> unsigned long sc_blk_cnt;
> unsigned long sc_datablk_cnt;
> unsigned long sc_nblk_this_inc;
> - time_t sc_seg_ctime;
> + time64_t sc_seg_ctime;
> __u64 sc_cno;
> unsigned long sc_flags;
>
> diff --git a/fs/nilfs2/sufile.c b/fs/nilfs2/sufile.c
> index 1341a41e7b43..c7fa139d50e8 100644
> --- a/fs/nilfs2/sufile.c
> +++ b/fs/nilfs2/sufile.c
> @@ -526,7 +526,7 @@ int nilfs_sufile_mark_dirty(struct inode *sufile, __u64 segnum)
> * @modtime: modification time (option)
> */
> int nilfs_sufile_set_segment_usage(struct inode *sufile, __u64 segnum,
> - unsigned long nblocks, time_t modtime)
> + unsigned long nblocks, time64_t modtime)
> {
> struct buffer_head *bh;
> struct nilfs_segment_usage *su;
> diff --git a/fs/nilfs2/sufile.h b/fs/nilfs2/sufile.h
> index 158a9190c8ec..673a891350f4 100644
> --- a/fs/nilfs2/sufile.h
> +++ b/fs/nilfs2/sufile.h
> @@ -35,7 +35,7 @@ int nilfs_sufile_set_alloc_range(struct inode *sufile, __u64 start, __u64 end);
> int nilfs_sufile_alloc(struct inode *, __u64 *);
> int nilfs_sufile_mark_dirty(struct inode *sufile, __u64 segnum);
> int nilfs_sufile_set_segment_usage(struct inode *sufile, __u64 segnum,
> - unsigned long nblocks, time_t modtime);
> + unsigned long nblocks, time64_t modtime);
> int nilfs_sufile_get_stat(struct inode *, struct nilfs_sustat *);
> ssize_t nilfs_sufile_get_suinfo(struct inode *, __u64, void *, unsigned int,
> size_t);
> diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
> index 3073b646e1ba..6ffeca84d7c3 100644
> --- a/fs/nilfs2/super.c
> +++ b/fs/nilfs2/super.c
> @@ -283,10 +283,10 @@ int nilfs_commit_super(struct super_block *sb, int flag)
> {
> struct the_nilfs *nilfs = sb->s_fs_info;
> struct nilfs_super_block **sbp = nilfs->ns_sbp;
> - time_t t;
> + time64_t t;
>
> /* nilfs->ns_sem must be locked by the caller. */
> - t = get_seconds();
> + t = ktime_get_real_seconds();
> nilfs->ns_sbwtime = t;
> sbp[0]->s_wtime = cpu_to_le64(t);
> sbp[0]->s_sum = 0;
> diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
> index 490303e3d517..4b25837e7724 100644
> --- a/fs/nilfs2/sysfs.c
> +++ b/fs/nilfs2/sysfs.c
> @@ -31,7 +31,7 @@ static struct kset *nilfs_kset;
> #define NILFS_SHOW_TIME(time_t_val, buf) ({ \
> struct tm res; \
> int count = 0; \
> - time_to_tm(time_t_val, 0, &res); \
> + time64_to_tm(time_t_val, 0, &res); \
> res.tm_year += 1900; \
> res.tm_mon += 1; \
> count = scnprintf(buf, PAGE_SIZE, \
> @@ -579,7 +579,7 @@ nilfs_segctor_last_seg_write_time_show(struct nilfs_segctor_attr *attr,
> struct the_nilfs *nilfs,
> char *buf)
> {
> - time_t ctime;
> + time64_t ctime;
>
> down_read(&nilfs->ns_segctor_sem);
> ctime = nilfs->ns_ctime;
> @@ -593,13 +593,13 @@ nilfs_segctor_last_seg_write_time_secs_show(struct nilfs_segctor_attr *attr,
> struct the_nilfs *nilfs,
> char *buf)
> {
> - time_t ctime;
> + time64_t ctime;
>
> down_read(&nilfs->ns_segctor_sem);
> ctime = nilfs->ns_ctime;
> up_read(&nilfs->ns_segctor_sem);
>
> - return snprintf(buf, PAGE_SIZE, "%llu\n", (unsigned long long)ctime);
> + return snprintf(buf, PAGE_SIZE, "%llu\n", ctime);
> }
>
> static ssize_t
> @@ -607,7 +607,7 @@ nilfs_segctor_last_nongc_write_time_show(struct nilfs_segctor_attr *attr,
> struct the_nilfs *nilfs,
> char *buf)
> {
> - time_t nongc_ctime;
> + time64_t nongc_ctime;
>
> down_read(&nilfs->ns_segctor_sem);
> nongc_ctime = nilfs->ns_nongc_ctime;
> @@ -621,14 +621,13 @@ nilfs_segctor_last_nongc_write_time_secs_show(struct nilfs_segctor_attr *attr,
> struct the_nilfs *nilfs,
> char *buf)
> {
> - time_t nongc_ctime;
> + time64_t nongc_ctime;
>
> down_read(&nilfs->ns_segctor_sem);
> nongc_ctime = nilfs->ns_nongc_ctime;
> up_read(&nilfs->ns_segctor_sem);
>
> - return snprintf(buf, PAGE_SIZE, "%llu\n",
> - (unsigned long long)nongc_ctime);
> + return snprintf(buf, PAGE_SIZE, "%llu\n", nongc_ctime);
> }
>
> static ssize_t
> @@ -728,7 +727,7 @@ nilfs_superblock_sb_write_time_show(struct nilfs_superblock_attr *attr,
> struct the_nilfs *nilfs,
> char *buf)
> {
> - time_t sbwtime;
> + time64_t sbwtime;
>
> down_read(&nilfs->ns_sem);
> sbwtime = nilfs->ns_sbwtime;
> @@ -742,13 +741,13 @@ nilfs_superblock_sb_write_time_secs_show(struct nilfs_superblock_attr *attr,
> struct the_nilfs *nilfs,
> char *buf)
> {
> - time_t sbwtime;
> + time64_t sbwtime;
>
> down_read(&nilfs->ns_sem);
> sbwtime = nilfs->ns_sbwtime;
> up_read(&nilfs->ns_sem);
>
> - return snprintf(buf, PAGE_SIZE, "%llu\n", (unsigned long long)sbwtime);
> + return snprintf(buf, PAGE_SIZE, "%llu\n", sbwtime);
> }
>
> static ssize_t
> diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
> index 883d732b0259..36da1779f976 100644
> --- a/fs/nilfs2/the_nilfs.h
> +++ b/fs/nilfs2/the_nilfs.h
> @@ -116,7 +116,7 @@ struct the_nilfs {
> */
> struct buffer_head *ns_sbh[2];
> struct nilfs_super_block *ns_sbp[2];
> - time_t ns_sbwtime;
> + time64_t ns_sbwtime;
> unsigned int ns_sbwcount;
> unsigned int ns_sbsize;
> unsigned int ns_mount_state;
> @@ -131,8 +131,8 @@ struct the_nilfs {
> __u64 ns_nextnum;
> unsigned long ns_pseg_offset;
> __u64 ns_cno;
> - time_t ns_ctime;
> - time_t ns_nongc_ctime;
> + time64_t ns_ctime;
> + time64_t ns_nongc_ctime;
> atomic_t ns_ndirtyblks;
>
> /*
> @@ -267,7 +267,7 @@ struct nilfs_root {
>
> static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
> {
> - u64 t = get_seconds();
> + u64 t = ktime_get_real_seconds();
>
> return t < nilfs->ns_sbwtime ||
> t > nilfs->ns_sbwtime + nilfs->ns_sb_update_freq;
> --
> 2.9.0
>
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