Linux 5.6 compat: timestamp_truncate()

The timestamp_truncate() function was added, it replaces the existing
timespec64_trunc() function.  This change renames our wrapper function
to be consistent with the upstream name and updates the compatibility
code for older kernels accordingly.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #9956
Closes #9961

config/kernel-inode-times.m4

@@ -1,8 +1,22 @@
-dnl #
-dnl # 4.18 API change
-dnl # i_atime, i_mtime, and i_ctime changed from timespec to timespec64.
-dnl #
 AC_DEFUN([ZFS_AC_KERNEL_SRC_INODE_TIMES], [
+
+	dnl #
+	dnl # 5.6 API change
+	dnl # timespec64_trunc() replaced by timestamp_truncate() interface.
+	dnl #
+	ZFS_LINUX_TEST_SRC([timestamp_truncate], [
+		#include <linux/fs.h>
+	],[
+		struct timespec64 ts;
+		struct inode ip;
+
+		ts = timestamp_truncate(ts, &ip);
+	])
+
+	dnl #
+	dnl # 4.18 API change
+	dnl # i_atime, i_mtime, and i_ctime changed from timespec to timespec64.
+	dnl #
 	ZFS_LINUX_TEST_SRC([inode_times], [
 		#include <linux/fs.h>
 	],[
@@ -15,6 +29,15 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_INODE_TIMES], [
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_INODE_TIMES], [
+	AC_MSG_CHECKING([whether timestamp_truncate() exists])
+	ZFS_LINUX_TEST_RESULT([timestamp_truncate], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_INODE_TIMESTAMP_TRUNCATE, 1,
+		    [timestamp_truncate() exists])
+	],[
+		AC_MSG_RESULT(no)
+	])
+
 	AC_MSG_CHECKING([whether inode->i_*time's are timespec64])
 	ZFS_LINUX_TEST_RESULT([inode_times], [
 		AC_MSG_RESULT(no)

include/os/linux/zfs/sys/zpl.h

@@ -170,13 +170,14 @@ 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)
+#if defined(HAVE_INODE_TIMESTAMP_TRUNCATE)
+#define	zpl_inode_timestamp_truncate(ts, ip)	timestamp_truncate(ts, ip)
+#elif defined(HAVE_INODE_TIMESPEC64_TIMES)
+#define	zpl_inode_timestamp_truncate(ts, ip)	\
+	timespec64_trunc(ts, (ip)->i_sb->s_time_gran)
 #else
-#define	zpl_inode_timespec_trunc(ts, gran)	timespec_trunc(ts, gran)
+#define	zpl_inode_timestamp_truncate(ts, ip)	\
+	timespec_trunc(ts, (ip)->i_sb->s_time_gran)
 #endif
 
 #endif	/* _SYS_ZPL_H */

module/os/linux/zfs/zfs_vnops.c

@@ -3444,17 +3444,17 @@ zfs_setattr(znode_t *zp, vattr_t *vap, int flags, cred_t *cr)
 
 	if (mask & (ATTR_MTIME | ATTR_SIZE)) {
 		ZFS_TIME_ENCODE(&vap->va_mtime, mtime);
-		ZTOI(zp)->i_mtime = zpl_inode_timespec_trunc(vap->va_mtime,
-		    ZTOI(zp)->i_sb->s_time_gran);
+		ZTOI(zp)->i_mtime = zpl_inode_timestamp_truncate(
+		    vap->va_mtime, ZTOI(zp));
 
 		SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MTIME(zfsvfs), NULL,
 		    mtime, sizeof (mtime));
 	}
 
 	if (mask & (ATTR_CTIME | ATTR_SIZE)) {
 		ZFS_TIME_ENCODE(&vap->va_ctime, ctime);
-		ZTOI(zp)->i_ctime = zpl_inode_timespec_trunc(vap->va_ctime,
-		    ZTOI(zp)->i_sb->s_time_gran);
+		ZTOI(zp)->i_ctime = zpl_inode_timestamp_truncate(vap->va_ctime,
+		    ZTOI(zp));
 		SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs), NULL,
 		    ctime, sizeof (ctime));
 	}

module/os/linux/zfs/zpl_inode.c

@@ -382,10 +382,8 @@ zpl_setattr(struct dentry *dentry, struct iattr *ia)
 	vap->va_mtime = ia->ia_mtime;
 	vap->va_ctime = ia->ia_ctime;
 
-	if (vap->va_mask & ATTR_ATIME) {
-		ip->i_atime = zpl_inode_timespec_trunc(ia->ia_atime,
-		    ip->i_sb->s_time_gran);
-	}
+	if (vap->va_mask & ATTR_ATIME)
+		ip->i_atime = zpl_inode_timestamp_truncate(ia->ia_atime, ip);
 
 	cookie = spl_fstrans_mark();
 	error = -zfs_setattr(ITOZ(ip), vap, 0, cr);