NFSv4.1: Handle NFS4ERR_BADSLOT errors correctly

Most (all) NFS4ERR_BADSLOT errors are due to the client failing to
respect the server's sr_highest_slotid limit. This mainly happens
due to reordered RPC requests.
The way to handle it is simply to drop the slot that we're using,
and retry using the new highest_slotid limits.

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

1 files changed, 12 insertions, 1 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 92bd799eee01..a4692e97bc19 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -422,6 +422,7 @@ static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *
         struct nfs4_slot *slot;
         unsigned long timestamp;
         struct nfs_client *clp;
+        int ret = 1;
 
         /*
          * sr_status remains 1 if an RPC level error occurred. The server
@@ -462,6 +463,16 @@ static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *
                         slot->slot_nr,
                         slot->seq_nr);
                 goto out_retry;
+        case -NFS4ERR_BADSLOT:
+                /*
+                 * The slot id we used was probably retired. Try again
+                 * using a different slot id.
+                 */
+                if (rpc_restart_call_prepare(task)) {
+                        task->tk_status = 0;
+                        ret = 0;
+                }
+                break;
         default:
                 /* Just update the slot sequence no. */
                 ++slot->seq_nr;
@@ -470,7 +481,7 @@ out:
         /* The session may be reset by one of the error handlers. */
         dprintk("%s: Error %d free the slot \n", __func__, res->sr_status);
         nfs41_sequence_free_slot(res);
-        return 1;
+        return ret;
 out_retry:
         if (!rpc_restart_call(task))
                 goto out;