NFSv4.1: filelayout async error handler

Use our own async error handler.
Mark the layout as failed and retry i/o through the MDS on specified errors.

Update the mds_offset in nfs_readpage_retry so that a failed short-read retry
to a DS gets correctly resent through the MDS.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 29 insertions, 6 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index d09623933302..1dc809039448 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3074,15 +3074,10 @@ static int nfs4_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
         return err;
 }
 
-static int nfs4_read_done(struct rpc_task *task, struct nfs_read_data *data)
+static int nfs4_read_done_cb(struct rpc_task *task, struct nfs_read_data *data)
 {
         struct nfs_server *server = NFS_SERVER(data->inode);
 
-        dprintk("--> %s\n", __func__);
-
-        if (!nfs4_sequence_done(task, &data->res.seq_res))
-                return -EAGAIN;
-
         if (nfs4_async_handle_error(task, server, data->args.context->state) == -EAGAIN) {
                 nfs_restart_rpc(task, server->nfs_client);
                 return -EAGAIN;
@@ -3094,12 +3089,40 @@ static int nfs4_read_done(struct rpc_task *task, struct nfs_read_data *data)
         return 0;
 }
 
+static int nfs4_read_done(struct rpc_task *task, struct nfs_read_data *data)
+{
+
+        dprintk("--> %s\n", __func__);
+
+        if (!nfs4_sequence_done(task, &data->res.seq_res))
+                return -EAGAIN;
+
+        return data->read_done_cb(task, data);
+}
+
 static void nfs4_proc_read_setup(struct nfs_read_data *data, struct rpc_message *msg)
 {
         data->timestamp   = jiffies;
+        data->read_done_cb = nfs4_read_done_cb;
         msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ];
 }
 
+/* Reset the the nfs_read_data to send the read to the MDS. */
+void nfs4_reset_read(struct rpc_task *task, struct nfs_read_data *data)
+{
+        dprintk("%s Reset task for i/o through\n", __func__);
+        put_lseg(data->lseg);
+        data->lseg = NULL;
+        /* offsets will differ in the dense stripe case */
+        data->args.offset = data->mds_offset;
+        data->ds_clp = NULL;
+        data->args.fh     = NFS_FH(data->inode);
+        data->read_done_cb = nfs4_read_done_cb;
+        task->tk_ops = data->mds_ops;
+        rpc_task_reset_client(task, NFS_CLIENT(data->inode));
+}
+EXPORT_SYMBOL_GPL(nfs4_reset_read);
+
 static int nfs4_write_done(struct rpc_task *task, struct nfs_write_data *data)
 {
         struct inode *inode = data->inode;