nilfs2: use time64_t internally

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.

Link: http://lkml.kernel.org/r/20180122211050.1286441-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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;