diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 0cf9d1cd9bd256c1f1ff4928f523fb48788b3b41..89527a487ed7d5365464bd6fe537c9014cfce117 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -174,8 +174,6 @@ static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int
 		return;
 	if (count != nfs_page_length(page))
 		return;
-	if (count != PAGE_CACHE_SIZE)
-		zero_user_page(page, count, PAGE_CACHE_SIZE - count, KM_USER0);
 	SetPageUptodate(page);
 }
 
@@ -627,7 +625,8 @@ static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
 				return ERR_PTR(error);
 			}
 			spin_unlock(&inode->i_lock);
-			return new;
+			req = new;
+			goto zero_page;
 		}
 		spin_unlock(&inode->i_lock);
 
@@ -655,13 +654,23 @@ static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
 	if (offset < req->wb_offset) {
 		req->wb_offset = offset;
 		req->wb_pgbase = offset;
-		req->wb_bytes = rqend - req->wb_offset;
+		req->wb_bytes = max(end, rqend) - req->wb_offset;
+		goto zero_page;
 	}
 
 	if (end > rqend)
 		req->wb_bytes = end - req->wb_offset;
 
 	return req;
+zero_page:
+	/* If this page might potentially be marked as up to date,
+	 * then we need to zero any uninitalised data. */
+	if (req->wb_pgbase == 0 && req->wb_bytes != PAGE_CACHE_SIZE
+			&& !PageUptodate(req->wb_page))
+		zero_user_page(req->wb_page, req->wb_bytes,
+				PAGE_CACHE_SIZE - req->wb_bytes,
+				KM_USER0);
+	return req;
 }
 
 int nfs_flush_incompatible(struct file *file, struct page *page)