From 55c30b5b99923b6078558f7f7209dbf0fb91b40d Mon Sep 17 00:00:00 2001
From: Andy Adamson <andros@netapp.com>
Date: Wed, 30 May 2012 16:12:24 -0400
Subject: [PATCH] --- yaml --- r: 310958 b: refs/heads/master c:
 2669940db8d02147181e338bb6db98394569f31a h: refs/heads/master v: v3

---
 [refs]                  |  2 +-
 trunk/fs/nfs/nfs4proc.c | 12 ++++++++----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/[refs] b/[refs]
index c5290ab4aed9..4320709e4036 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 64f9a83665e4f168ff50ce1db9eb175f954048fa
+refs/heads/master: 2669940db8d02147181e338bb6db98394569f31a
diff --git a/trunk/fs/nfs/nfs4proc.c b/trunk/fs/nfs/nfs4proc.c
index f23977e4ac0f..15fc7e4664ed 100644
--- a/trunk/fs/nfs/nfs4proc.c
+++ b/trunk/fs/nfs/nfs4proc.c
@@ -2549,6 +2549,14 @@ nfs4_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
 
 	nfs_fattr_init(fattr);
 	
+	/* Deal with open(O_TRUNC) */
+	if (sattr->ia_valid & ATTR_OPEN)
+		sattr->ia_valid &= ~(ATTR_MTIME|ATTR_CTIME|ATTR_OPEN);
+
+	/* Optimization: if the end result is no change, don't RPC */
+	if ((sattr->ia_valid & ~(ATTR_FILE)) == 0)
+		return 0;
+
 	/* Search for an existing open(O_WRITE) file */
 	if (sattr->ia_valid & ATTR_FILE) {
 		struct nfs_open_context *ctx;
@@ -2560,10 +2568,6 @@ nfs4_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
 		}
 	}
 
-	/* Deal with open(O_TRUNC) */
-	if (sattr->ia_valid & ATTR_OPEN)
-		sattr->ia_valid &= ~(ATTR_MTIME|ATTR_CTIME|ATTR_OPEN);
-
 	status = nfs4_do_setattr(inode, cred, fattr, sattr, state);
 	if (status == 0)
 		nfs_setattr_update_inode(inode, sattr);