NFSv4.1: We must release the sequence id when we fail to get a session slot

If we do not release the sequence id in cases where we fail to get a
session slot, then we can deadlock if we hit a recovery scenario.

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

1 files changed, 23 insertions, 13 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index d5fbf1f49d5f..e0423bb5a880 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1571,9 +1571,11 @@ static void nfs4_open_prepare(struct rpc_task *task, void *calldata)
         data->timestamp = jiffies;
         if (nfs4_setup_sequence(data->o_arg.server,
                                 &data->o_arg.seq_args,
-                                &data->o_res.seq_res, task))
-                return;
-        rpc_call_start(task);
+                                &data->o_res.seq_res,
+                                task) != 0)
+                nfs_release_seqid(data->o_arg.seqid);
+        else
+                rpc_call_start(task);
         return;
 unlock_no_action:
         rcu_read_unlock();
@@ -2295,9 +2297,10 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data)
         if (nfs4_setup_sequence(NFS_SERVER(inode),
                                 &calldata->arg.seq_args,
                                 &calldata->res.seq_res,
-                                task))
-                goto out;
-        rpc_call_start(task);
+                                task) != 0)
+                nfs_release_seqid(calldata->arg.seqid);
+        else
+                rpc_call_start(task);
 out:
         dprintk("%s: done!\n", __func__);
 }
@@ -4544,9 +4547,11 @@ static void nfs4_locku_prepare(struct rpc_task *task, void *data)
         calldata->timestamp = jiffies;
         if (nfs4_setup_sequence(calldata->server,
                                 &calldata->arg.seq_args,
-                                &calldata->res.seq_res, task))
-                return;
-        rpc_call_start(task);
+                                &calldata->res.seq_res,
+                                task) != 0)
+                nfs_release_seqid(calldata->arg.seqid);
+        else
+                rpc_call_start(task);
 }
 
 static const struct rpc_call_ops nfs4_locku_ops = {
@@ -4691,7 +4696,7 @@ static void nfs4_lock_prepare(struct rpc_task *task, void *calldata)
         /* Do we need to do an open_to_lock_owner? */
         if (!(data->arg.lock_seqid->sequence->flags & NFS_SEQID_CONFIRMED)) {
                 if (nfs_wait_on_sequence(data->arg.open_seqid, task) != 0)
-                        return;
+                        goto out_release_lock_seqid;
                 data->arg.open_stateid = &state->stateid;
                 data->arg.new_lock_owner = 1;
                 data->res.open_seqid = data->arg.open_seqid;
@@ -4700,10 +4705,15 @@ static void nfs4_lock_prepare(struct rpc_task *task, void *calldata)
         data->timestamp = jiffies;
         if (nfs4_setup_sequence(data->server,
                                 &data->arg.seq_args,
-                                &data->res.seq_res, task))
+                                &data->res.seq_res,
+                                task) == 0) {
+                rpc_call_start(task);
                 return;
-        rpc_call_start(task);
-        dprintk("%s: done!, ret = %d\n", __func__, data->rpc_status);
+        }
+        nfs_release_seqid(data->arg.open_seqid);
+out_release_lock_seqid:
+        nfs_release_seqid(data->arg.lock_seqid);
+        dprintk("%s: done!, ret = %d\n", __func__, task->tk_status);
 }
 
 static void nfs4_recover_lock_prepare(struct rpc_task *task, void *calldata)