NFSv4.1: Handle NFS4ERR_DELAY when resetting the NFSv4.1 session

NFS4ERR_DELAY is a legal reply when we call DESTROY_SESSION. It
usually means that the server is busy handling an unfinished RPC
request. Just sleep for a second and then retry.
We also need to be able to handle the NFS4ERR_BACK_CHAN_BUSY return
value. If the NFS server has outstanding callbacks, we just want to
similarly sleep & retry.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

1 files changed, 12 insertions, 2 deletions

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index f72561ca6895..e61f68d5ef21 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -2018,8 +2018,18 @@ static int nfs4_reset_session(struct nfs_client *clp)
         nfs4_begin_drain_session(clp);
         cred = nfs4_get_exchange_id_cred(clp);
         status = nfs4_proc_destroy_session(clp->cl_session, cred);
-        if (status && status != -NFS4ERR_BADSESSION &&
-            status != -NFS4ERR_DEADSESSION) {
+        switch (status) {
+        case 0:
+        case -NFS4ERR_BADSESSION:
+        case -NFS4ERR_DEADSESSION:
+                break;
+        case -NFS4ERR_BACK_CHAN_BUSY:
+        case -NFS4ERR_DELAY:
+                set_bit(NFS4CLNT_SESSION_RESET, &clp->cl_state);
+                status = 0;
+                ssleep(1);
+                goto out;
+        default:
                 status = nfs4_recovery_handle_error(clp, status);
                 goto out;
         }