[PATCH RFC] nfs4: use adaptive backoff when we get NFS4ERR_DELAY on LAYOUTGET

[Jeff Layton <jlayton@poochiereds.net>]

Currently, we end up waiting a full 15s before reissuing the call
because we're passing in NULL for the timeout.

Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
---
 fs/nfs/nfs4proc.c       | 3 ++-
 include/linux/nfs_xdr.h | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 5133bb18830e..b4098319b021 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -7872,7 +7872,7 @@ static void nfs4_layoutget_done(struct rpc_task *task, void *calldata)
 			spin_unlock(&inode->i_lock);
 		goto out_restart;
 	}
-	if (nfs4_async_handle_error(task, server, state, NULL) == -EAGAIN)
+	if (nfs4_async_handle_error(task, server, state, &lgp->timeout) == -EAGAIN)
 		goto out_restart;
 out:
 	dprintk("<-- %s\n", __func__);
@@ -7990,6 +7990,7 @@ nfs4_proc_layoutget(struct nfs4_layoutget *lgp, gfp_t gfp_flags)
 	lgp->res.layoutp = &lgp->args.layout;
 	lgp->res.seq_res.sr_slot = NULL;
 	nfs4_init_sequence(&lgp->args.seq_args, &lgp->res.seq_res, 0);
+	lgp->timeout = 0;
 
 	task = rpc_run_task(&task_setup_data);
 	if (IS_ERR(task))
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 52faf7e96c65..0ab65cb7d15b 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -250,6 +250,7 @@ struct nfs4_layoutget {
 	struct nfs4_layoutget_res res;
 	struct rpc_cred *cred;
 	gfp_t gfp_flags;
+	long timeout;
 };
 
 struct nfs4_getdeviceinfo_args {
-- 
2.4.3