Linux 4.18 compat: inode timespec -> timespec64

Commit torvalds/linux@95582b0 changes the inode i_atime, i_mtime,
and i_ctime members form timespec's to timespec64's to make them
2038 safe.  As part of this change the current_time() function was
also updated to return the timespec64 type.

Resolve this issue by introducing a new inode_timespec_t type which
is defined to match the timespec type used by the inode.  It should
be used when working with inode timestamps to ensure matching types.

The timestruc_t type under Illumos was used in a similar fashion but
was specified to always be a timespec_t.  Rather than incorrectly
define this type all timespec_t types have been replaced by the new
inode_timespec_t type.

Finally, the kernel and user space 'sys/time.h' headers were aligned
with each other.  They define as appropriate for the context several
constants as macros and include static inline implementation of
gethrestime(), gethrestime_sec(), and gethrtime().

Reviewed-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #7643

include/spl/sys/condvar.h

@@ -30,6 +30,7 @@
 #include <sys/mutex.h>
 #include <sys/callo.h>
 #include <sys/wait.h>
+#include <sys/time.h>
 
 /*
  * The kcondvar_t struct is protected by mutex taken externally before

include/spl/sys/time.h

@@ -54,13 +54,26 @@
 
 static const int hz = HZ;
 
+typedef longlong_t		hrtime_t;
+typedef struct timespec		timespec_t;
+
 #define	TIMESPEC_OVERFLOW(ts)		\
 	((ts)->tv_sec < TIME_MIN || (ts)->tv_sec > TIME_MAX)
 
+#if defined(HAVE_INODE_TIMESPEC64_TIMES)
+typedef struct timespec64	inode_timespec_t;
+#else
+typedef struct timespec		inode_timespec_t;
+#endif
+
 static inline void
-gethrestime(timestruc_t *now)
+gethrestime(inode_timespec_t *ts)
 {
-	*now = current_kernel_time();
+#if defined(HAVE_INODE_TIMESPEC64_TIMES)
+	*ts = current_kernel_time64();
+#else
+	*ts = current_kernel_time();
+#endif
 }
 
 static inline time_t
@@ -74,9 +87,9 @@ gethrestime_sec(void)
 static inline hrtime_t
 gethrtime(void)
 {
-	struct timespec now;
-	getrawmonotonic(&now);
-	return (((hrtime_t)now.tv_sec * NSEC_PER_SEC) + now.tv_nsec);
+	struct timespec ts;
+	getrawmonotonic(&ts);
+	return (((hrtime_t)ts.tv_sec * NSEC_PER_SEC) + ts.tv_nsec);
 }
 
 #endif  /* _SPL_TIME_H */

include/spl/sys/types.h

@@ -53,10 +53,6 @@ typedef unsigned long long	rlim64_t;
 typedef struct task_struct	kthread_t;
 typedef struct task_struct	proc_t;
 
-typedef struct timespec		timestruc_t;
-typedef struct timespec		timespec_t;
-typedef longlong_t		hrtime_t;
-
 typedef int			id_t;
 typedef short			pri_t;
 typedef short			index_t;

include/spl/sys/vnode.h

@@ -128,9 +128,9 @@ typedef struct vattr {
 	long		va_nodeid;	/* node # */
 	uint32_t	va_nlink;	/* # links */
 	uint64_t	va_size;	/* file size */
-	struct timespec	va_atime;	/* last acc */
-	struct timespec	va_mtime;	/* last mod */
-	struct timespec	va_ctime;	/* last chg */
+	inode_timespec_t va_atime;	/* last acc */
+	inode_timespec_t va_mtime;	/* last mod */
+	inode_timespec_t va_ctime;	/* last chg */
 	dev_t		va_rdev;	/* dev */
 	uint64_t	va_nblocks;	/* space used */
 	uint32_t	va_blksize;	/* block size */