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define this type all timespec_t types have been replaced by the new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
Backported-by: Richard Yao <ryao@gentoo.org>

include/sys/dmu.h

@@ -891,7 +891,7 @@ uint64_t dmu_objset_fsid_guid(objset_t *os);
 /*
  * Get the [cm]time for an objset's snapshot dir
  */
-timestruc_t dmu_objset_snap_cmtime(objset_t *os);
+inode_timespec_t dmu_objset_snap_cmtime(objset_t *os);
 
 int dmu_objset_is_snapshot(objset_t *os);
 

include/sys/dmu_objset.h

@@ -179,7 +179,7 @@ int dmu_objset_find_dp(struct dsl_pool *dp, uint64_t ddobj,
     int func(struct dsl_pool *, struct dsl_dataset *, void *),
     void *arg, int flags);
 void dmu_objset_evict_dbufs(objset_t *os);
-timestruc_t dmu_objset_snap_cmtime(objset_t *os);
+inode_timespec_t dmu_objset_snap_cmtime(objset_t *os);
 
 /* called from dsl */
 void dmu_objset_sync(objset_t *os, zio_t *zio, dmu_tx_t *tx);

include/sys/dsl_dir.h

@@ -103,7 +103,7 @@ struct dsl_dir {
 	/* Protected by dd_lock */
 	kmutex_t dd_lock;
 	list_t dd_props; /* list of dsl_prop_record_t's */
-	timestruc_t dd_snap_cmtime; /* last time snapshot namespace changed */
+	inode_timespec_t dd_snap_cmtime; /* last snapshot namespace change */
 	uint64_t dd_origin_txg;
 
 	/* gross estimate of space used by in-flight tx's */
@@ -159,7 +159,7 @@ boolean_t dsl_dir_is_clone(dsl_dir_t *dd);
 void dsl_dir_new_refreservation(dsl_dir_t *dd, struct dsl_dataset *ds,
     uint64_t reservation, cred_t *cr, dmu_tx_t *tx);
 void dsl_dir_snap_cmtime_update(dsl_dir_t *dd);
-timestruc_t dsl_dir_snap_cmtime(dsl_dir_t *dd);
+inode_timespec_t dsl_dir_snap_cmtime(dsl_dir_t *dd);
 void dsl_dir_set_reservation_sync_impl(dsl_dir_t *dd, uint64_t value,
     dmu_tx_t *tx);
 void dsl_dir_zapify(dsl_dir_t *dd, dmu_tx_t *tx);

include/sys/spa_impl.h

@@ -153,7 +153,7 @@ struct spa {
 	uint64_t	spa_freeze_txg;		/* freeze pool at this txg */
 	uint64_t	spa_load_max_txg;	/* best initial ub_txg */
 	uint64_t	spa_claim_max_txg;	/* highest claimed birth txg */
-	timespec_t	spa_loaded_ts;		/* 1st successful open time */
+	inode_timespec_t spa_loaded_ts;		/* 1st successful open time */
 	objset_t	*spa_meta_objset;	/* copy of dp->dp_meta_objset */
 	kmutex_t	spa_evicting_os_lock;	/* Evicting objset list lock */
 	list_t		spa_evicting_os_list;	/* Objsets being evicted. */

include/sys/xvattr.h

@@ -47,7 +47,7 @@
  * Structure of all optional attributes.
  */
 typedef struct xoptattr {
-	timestruc_t	xoa_createtime;	/* Create time of file */
+	inode_timespec_t xoa_createtime;	/* Create time of file */
 	uint8_t		xoa_archive;
 	uint8_t		xoa_system;
 	uint8_t		xoa_readonly;

include/sys/zfs_context.h

@@ -527,7 +527,7 @@ extern char *vn_dumpdir;
 #define	AV_SCANSTAMP_SZ	32		/* length of anti-virus scanstamp */
 
 typedef struct xoptattr {
-	timestruc_t	xoa_createtime;	/* Create time of file */
+	inode_timespec_t xoa_createtime;	/* Create time of file */
 	uint8_t		xoa_archive;
 	uint8_t		xoa_system;
 	uint8_t		xoa_readonly;
@@ -640,13 +640,6 @@ extern void delay(clock_t ticks);
 #define	USEC_TO_TICK(usec)	((usec) / (MICROSEC / hz))
 #define	NSEC_TO_TICK(usec)	((usec) / (NANOSEC / hz))
 
-#define	gethrestime_sec() time(NULL)
-#define	gethrestime(t) \
-	do {\
-		(t)->tv_sec = gethrestime_sec();\
-		(t)->tv_nsec = 0;\
-	} while (0);
-
 #define	max_ncpus	64
 #define	boot_ncpus	(sysconf(_SC_NPROCESSORS_ONLN))
 

include/sys/zfs_znode.h

@@ -270,19 +270,36 @@ typedef struct znode_hold {
 
 extern unsigned int zfs_object_mutex_size;
 
-/* Encode ZFS stored time values from a struct timespec */
+/*
+ * Encode ZFS stored time values from a struct timespec / struct timespec64.
+ */
 #define	ZFS_TIME_ENCODE(tp, stmp)		\
-{						\
+do {						\
 	(stmp)[0] = (uint64_t)(tp)->tv_sec;	\
 	(stmp)[1] = (uint64_t)(tp)->tv_nsec;	\
-}
+} while (0)
 
-/* Decode ZFS stored time values to a struct timespec */
+#if defined(HAVE_INODE_TIMESPEC64_TIMES)
+/*
+ * Decode ZFS stored time values to a struct timespec64
+ * 4.18 and newer kernels.
+ */
 #define	ZFS_TIME_DECODE(tp, stmp)		\
-{						\
-	(tp)->tv_sec = (time_t)(stmp)[0];		\
-	(tp)->tv_nsec = (long)(stmp)[1];		\
-}
+do {						\
+	(tp)->tv_sec = (time64_t)(stmp)[0];	\
+	(tp)->tv_nsec = (long)(stmp)[1];	\
+} while (0)
+#else
+/*
+ * Decode ZFS stored time values to a struct timespec
+ * 4.17 and older kernels.
+ */
+#define	ZFS_TIME_DECODE(tp, stmp)		\
+do {						\
+	(tp)->tv_sec = (time_t)(stmp)[0];	\
+	(tp)->tv_nsec = (long)(stmp)[1];	\
+} while (0)
+#endif /* HAVE_INODE_TIMESPEC64_TIMES */
 
 /*
  * Timestamp defines

include/sys/zpl.h

@@ -189,4 +189,13 @@ zpl_dir_emit_dots(struct file *file, zpl_dir_context_t *ctx)
 }
 #endif /* HAVE_VFS_ITERATE */
 
+/*
+ * Linux 4.18, inode times converted from timespec to timespec64.
+ */
+#if defined(HAVE_INODE_TIMESPEC64_TIMES)
+#define	zpl_inode_timespec_trunc(ts, gran)	timespec64_trunc(ts, gran)
+#else
+#define	zpl_inode_timespec_trunc(ts, gran)	timespec_trunc(ts, gran)
+#endif
+
 #endif	/* _SYS_ZPL_H */