NFS: Don't zap caches on fallocate()

This patch adds a GETATTR to the end of ALLOCATE and DEALLOCATE
operations so we can set the updated inode size and change attribute
directly.  DEALLOCATE will still need to release pagecache pages, so
nfs42_proc_deallocate() now calls truncate_pagecache_range() before
contacting the server.

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/nfs42proc.c b/fs/nfs/nfs42proc.c
index cb17072..b9aa6bb 100644
--- a/fs/nfs/nfs42proc.c
+++ b/fs/nfs/nfs42proc.c
@@ -36,13 +36,16 @@
 				 loff_t offset, loff_t len)
 {
 	struct inode *inode = file_inode(filep);
+	struct nfs_server *server = NFS_SERVER(inode);
 	struct nfs42_falloc_args args = {
 		.falloc_fh	= NFS_FH(inode),
 		.falloc_offset	= offset,
 		.falloc_length	= len,
+		.falloc_bitmask	= server->cache_consistency_bitmask,
 	};
-	struct nfs42_falloc_res res;
-	struct nfs_server *server = NFS_SERVER(inode);
+	struct nfs42_falloc_res res = {
+		.falloc_server	= server,
+	};
 	int status;
 
 	msg->rpc_argp = &args;
@@ -52,8 +55,17 @@
 	if (status)
 		return status;
 
-	return nfs4_call_sync(server->client, server, msg,
-			      &args.seq_args, &res.seq_res, 0);
+	res.falloc_fattr = nfs_alloc_fattr();
+	if (!res.falloc_fattr)
+		return -ENOMEM;
+
+	status = nfs4_call_sync(server->client, server, msg,
+				&args.seq_args, &res.seq_res, 0);
+	if (status == 0)
+		status = nfs_post_op_update_inode(inode, res.falloc_fattr);
+
+	kfree(res.falloc_fattr);
+	return status;
 }
 
 static int nfs42_proc_fallocate(struct rpc_message *msg, struct file *filep,
@@ -101,7 +113,10 @@
 	if (!nfs_server_capable(inode, NFS_CAP_DEALLOCATE))
 		return -EOPNOTSUPP;
 
+	nfs_wb_all(inode);
 	err = nfs42_proc_fallocate(&msg, filep, offset, len);
+	if (err == 0)
+		truncate_pagecache_range(inode, offset, (offset + len) -1);
 	if (err == -EOPNOTSUPP)
 		NFS_SERVER(inode)->caps &= ~NFS_CAP_DEALLOCATE;
 	return err;