[PATCH 06/19] nfs: remove timespec from xdr_encode_nfstime

[Arnd Bergmann <arnd@xxxxxxxx>]

For NFSv2 and NFSv3, timestamps are stored using 32-bit entities
and overflow in y2038. For historic reasons we truncate the
64-bit timestamps by converting from a timespec64 to a timespec
first.

Remove this unnecessary conversion step and do the truncation
in the final functions that take a timestamp.

This is transparent to users, but avoids one of the last uses
of 'timespec' and lets us remove it later.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
 fs/nfs/nfs2xdr.c        | 31 +++++++++++++------------------
 fs/nfs/nfs3xdr.c        | 12 ++++--------
 include/linux/nfs_xdr.h |  2 +-
 3 files changed, 18 insertions(+), 27 deletions(-)

diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c
index d4e144712034..0b8399fee8f7 100644
--- a/fs/nfs/nfs2xdr.c
+++ b/fs/nfs/nfs2xdr.c
@@ -209,9 +209,9 @@ static int decode_fhandle(struct xdr_stream *xdr, struct nfs_fh *fh)
  *		unsigned int useconds;
  *	};
  */
-static __be32 *xdr_encode_time(__be32 *p, const struct timespec *timep)
+static __be32 *xdr_encode_time(__be32 *p, const struct timespec64 *timep)
 {
-	*p++ = cpu_to_be32(timep->tv_sec);
+	*p++ = cpu_to_be32((u32)timep->tv_sec);
 	if (timep->tv_nsec != 0)
 		*p++ = cpu_to_be32(timep->tv_nsec / NSEC_PER_USEC);
 	else
@@ -227,7 +227,7 @@ static __be32 *xdr_encode_time(__be32 *p, const struct timespec *timep)
  * Illustrated" by Brent Callaghan, Addison-Wesley, ISBN 0-201-32750-5.
  */
 static __be32 *xdr_encode_current_server_time(__be32 *p,
-					      const struct timespec *timep)
+					      const struct timespec64 *timep)
 {
 	*p++ = cpu_to_be32(timep->tv_sec);
 	*p++ = cpu_to_be32(1000000);
@@ -339,7 +339,6 @@ static __be32 *xdr_time_not_set(__be32 *p)
 static void encode_sattr(struct xdr_stream *xdr, const struct iattr *attr,
 		struct user_namespace *userns)
 {
-	struct timespec ts;
 	__be32 *p;
 
 	p = xdr_reserve_space(xdr, NFS_sattr_sz << 2);
@@ -361,21 +360,17 @@ static void encode_sattr(struct xdr_stream *xdr, const struct iattr *attr,
 	else
 		*p++ = cpu_to_be32(NFS2_SATTR_NOT_SET);
 
-	if (attr->ia_valid & ATTR_ATIME_SET) {
-		ts = timespec64_to_timespec(attr->ia_atime);
-		p = xdr_encode_time(p, &ts);
-	} else if (attr->ia_valid & ATTR_ATIME) {
-		ts = timespec64_to_timespec(attr->ia_atime);
-		p = xdr_encode_current_server_time(p, &ts);
-	} else
+	if (attr->ia_valid & ATTR_ATIME_SET)
+		p = xdr_encode_time(p, &attr->ia_atime);
+	else if (attr->ia_valid & ATTR_ATIME)
+		p = xdr_encode_current_server_time(p, &attr->ia_atime);
+	else
 		p = xdr_time_not_set(p);
-	if (attr->ia_valid & ATTR_MTIME_SET) {
-		ts = timespec64_to_timespec(attr->ia_atime);
-		xdr_encode_time(p, &ts);
-	} else if (attr->ia_valid & ATTR_MTIME) {
-		ts = timespec64_to_timespec(attr->ia_mtime);
-		xdr_encode_current_server_time(p, &ts);
-	} else
+	if (attr->ia_valid & ATTR_MTIME_SET)
+		xdr_encode_time(p, &attr->ia_atime);
+	else if (attr->ia_valid & ATTR_MTIME)
+		xdr_encode_current_server_time(p, &attr->ia_mtime);
+	else
 		xdr_time_not_set(p);
 }
 
diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index 2a16bbda3937..927eb680f161 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -456,9 +456,9 @@ static void zero_nfs_fh3(struct nfs_fh *fh)
  *		uint32	nseconds;
  *	};
  */
-static __be32 *xdr_encode_nfstime3(__be32 *p, const struct timespec *timep)
+static __be32 *xdr_encode_nfstime3(__be32 *p, const struct timespec64 *timep)
 {
-	*p++ = cpu_to_be32(timep->tv_sec);
+	*p++ = cpu_to_be32((u32)timep->tv_sec);
 	*p++ = cpu_to_be32(timep->tv_nsec);
 	return p;
 }
@@ -533,7 +533,6 @@ static __be32 *xdr_decode_nfstime3(__be32 *p, struct timespec64 *timep)
 static void encode_sattr3(struct xdr_stream *xdr, const struct iattr *attr,
 		struct user_namespace *userns)
 {
-	struct timespec ts;
 	u32 nbytes;
 	__be32 *p;
 
@@ -583,10 +582,8 @@ static void encode_sattr3(struct xdr_stream *xdr, const struct iattr *attr,
 		*p++ = xdr_zero;
 
 	if (attr->ia_valid & ATTR_ATIME_SET) {
-		struct timespec ts;
 		*p++ = xdr_two;
-		ts = timespec64_to_timespec(attr->ia_atime);
-		p = xdr_encode_nfstime3(p, &ts);
+		p = xdr_encode_nfstime3(p, &attr->ia_atime);
 	} else if (attr->ia_valid & ATTR_ATIME) {
 		*p++ = xdr_one;
 	} else
@@ -594,8 +591,7 @@ static void encode_sattr3(struct xdr_stream *xdr, const struct iattr *attr,
 
 	if (attr->ia_valid & ATTR_MTIME_SET) {
 		*p++ = xdr_two;
-		ts = timespec64_to_timespec(attr->ia_mtime);
-		xdr_encode_nfstime3(p, &ts);
+		xdr_encode_nfstime3(p, &attr->ia_mtime);
 	} else if (attr->ia_valid & ATTR_MTIME) {
 		*p = xdr_one;
 	} else
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index db5c01001937..22bc6613474e 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -869,7 +869,7 @@ struct nfs3_sattrargs {
 	struct nfs_fh *		fh;
 	struct iattr *		sattr;
 	unsigned int		guard;
-	struct timespec		guardtime;
+	struct timespec64	guardtime;
 };
 
 struct nfs3_diropargs {
-- 
2.20.0