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, 81 insertions, 0 deletions

diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index 3608411653dc..6a424c19abea 100644
--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -40,6 +40,8 @@ MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Dean Hildebrand <dhildebz@umich.edu>");
 MODULE_DESCRIPTION("The NFSv4 file layout driver");
 
+#define FILELAYOUT_POLL_RETRY_MAX     (15*HZ)
+
 static int
 filelayout_set_layoutdriver(struct nfs_server *nfss)
 {
@@ -100,6 +102,83 @@ filelayout_get_dserver_offset(struct pnfs_layout_segment *lseg, loff_t offset)
         BUG();
 }
 
+/* For data server errors we don't recover from */
+static void
+filelayout_set_lo_fail(struct pnfs_layout_segment *lseg)
+{
+        if (lseg->pls_range.iomode == IOMODE_RW) {
+                dprintk("%s Setting layout IOMODE_RW fail bit\n", __func__);
+                set_bit(lo_fail_bit(IOMODE_RW), &lseg->pls_layout->plh_flags);
+        } else {
+                dprintk("%s Setting layout IOMODE_READ fail bit\n", __func__);
+                set_bit(lo_fail_bit(IOMODE_READ), &lseg->pls_layout->plh_flags);
+        }
+}
+
+static int filelayout_async_handle_error(struct rpc_task *task,
+                                         struct nfs4_state *state,
+                                         struct nfs_client *clp,
+                                         int *reset)
+{
+        if (task->tk_status >= 0)
+                return 0;
+
+        *reset = 0;
+
+        switch (task->tk_status) {
+        case -NFS4ERR_BADSESSION:
+        case -NFS4ERR_BADSLOT:
+        case -NFS4ERR_BAD_HIGH_SLOT:
+        case -NFS4ERR_DEADSESSION:
+        case -NFS4ERR_CONN_NOT_BOUND_TO_SESSION:
+        case -NFS4ERR_SEQ_FALSE_RETRY:
+        case -NFS4ERR_SEQ_MISORDERED:
+                dprintk("%s ERROR %d, Reset session. Exchangeid "
+                        "flags 0x%x\n", __func__, task->tk_status,
+                        clp->cl_exchange_flags);
+                nfs4_schedule_session_recovery(clp->cl_session);
+                break;
+        case -NFS4ERR_DELAY:
+        case -NFS4ERR_GRACE:
+        case -EKEYEXPIRED:
+                rpc_delay(task, FILELAYOUT_POLL_RETRY_MAX);
+                break;
+        default:
+                dprintk("%s DS error. Retry through MDS %d\n", __func__,
+                        task->tk_status);
+                *reset = 1;
+                break;
+        }
+        task->tk_status = 0;
+        return -EAGAIN;
+}
+
+/* NFS_PROTO call done callback routines */
+
+static int filelayout_read_done_cb(struct rpc_task *task,
+                                struct nfs_read_data *data)
+{
+        struct nfs_client *clp = data->ds_clp;
+        int reset = 0;
+
+        dprintk("%s DS read\n", __func__);
+
+        if (filelayout_async_handle_error(task, data->args.context->state,
+                                          data->ds_clp, &reset) == -EAGAIN) {
+                dprintk("%s calling restart ds_clp %p ds_clp->cl_session %p\n",
+                        __func__, data->ds_clp, data->ds_clp->cl_session);
+                if (reset) {
+                        filelayout_set_lo_fail(data->lseg);
+                        nfs4_reset_read(task, data);
+                        clp = NFS_SERVER(data->inode)->nfs_client;
+                }
+                nfs_restart_rpc(task, clp);
+                return -EAGAIN;
+        }
+
+        return 0;
+}
+
 /*
  * Call ops for the async read/write cases
  * In the case of dense layouts, the offset needs to be reset to its
@@ -109,6 +188,8 @@ static void filelayout_read_prepare(struct rpc_task *task, void *data)
 {
         struct nfs_read_data *rdata = (struct nfs_read_data *)data;
 
+        rdata->read_done_cb = filelayout_read_done_cb;
+
         if (nfs41_setup_sequence(rdata->ds_clp->cl_session,
                                 &rdata->args.seq_args, &rdata->res.seq_res,
                                 0, task))