NFS: Request a directory delegation during RENAME

If we notice that we're renaming a file within a directory then we take
that as a sign that the user is working with the current directory and
may want a delegation to avoid extra revalidations when possible.

The nfs_request_directory_delegation() function exists within the NFS v4
module, so I add an extra flag to rename_setup() to indicate if a dentry
is being renamed within the same parent directory.

Signed-off-by: Anna Schumaker <[e-mail]>
Signed-off-by: Trond Myklebust <[e-mail]>

fs/nfs/nfs3proc.c

···
 static void
 nfs3_proc_rename_setup(struct rpc_message *msg,
 		struct dentry *old_dentry,
-		struct dentry *new_dentry)
+		struct dentry *new_dentry,
+		struct inode *same_parent)
 {
 	msg->rpc_proc = &nfs3_procedures[NFS3PROC_RENAME];
 }

fs/nfs/nfs4proc.c

···
 
 static void nfs4_proc_rename_setup(struct rpc_message *msg,
 		struct dentry *old_dentry,
-		struct dentry *new_dentry)
+		struct dentry *new_dentry,
+		struct inode *same_parent)
 {
 	struct nfs_renameargs *arg = msg->rpc_argp;
 	struct nfs_renameres *res = msg->rpc_resp;
···
 		nfs4_inode_make_writeable(old_inode);
 	if (new_inode)
 		nfs4_inode_return_delegation(new_inode);
+	if (same_parent)
+		nfs_request_directory_delegation(same_parent);
 	msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_RENAME];
 	res->server = NFS_SB(old_dentry->d_sb);
 	nfs4_init_sequence(&arg->seq_args, &res->seq_res, 1, 0);

fs/nfs/proc.c

···
 static void
 nfs_proc_rename_setup(struct rpc_message *msg,
 		struct dentry *old_dentry,
-		struct dentry *new_dentry)
+		struct dentry *new_dentry,
+		struct inode *same_parent)
 {
 	msg->rpc_proc = &nfs_procedures[NFSPROC_RENAME];
 }

fs/nfs/unlink.c

···
 
 	nfs_sb_active(old_dir->i_sb);
 
-	NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dentry, new_dentry);
+	NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dentry, new_dentry,
+					old_dir == new_dir ? old_dir : NULL);
 
 	return rpc_run_task(&task_setup_data);
 }

include/linux/nfs_xdr.h

···
 	int	(*unlink_done) (struct rpc_task *, struct inode *);
 	void	(*rename_setup)  (struct rpc_message *msg,
 			struct dentry *old_dentry,
-			struct dentry *new_dentry);
+			struct dentry *new_dentry,
+			struct inode *same_parent);
 	void	(*rename_rpc_prepare)(struct rpc_task *task, struct nfs_renamedata *);
 	int	(*rename_done) (struct rpc_task *task, struct inode *old_dir, struct inode *new_dir);
 	int	(*link)    (struct inode *, struct inode *, const struct qstr *);