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

commit 2240a9e2d013d8269ea425b73e1d7a54c7bc141f upstream.

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>
[bwh: Backported to 3.2:
 - Adjust context
 - nfs4_setup_sequence() has an additional 'cache_reply' parameter]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 2468fac..4f07b56 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1463,9 +1463,11 @@ 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, 1, task))
-               return;
-       rpc_call_start(task);
+                               &data->o_res.seq_res,
+                               1, task) != 0)
+               nfs_release_seqid(data->o_arg.seqid);
+       else
+               rpc_call_start(task);
        return;
 unlock_no_action:
        rcu_read_unlock();
@@ -2045,9 +2047,10 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data)
        calldata->timestamp = jiffies;
        if (nfs4_setup_sequence(NFS_SERVER(calldata->inode),
                                &calldata->arg.seq_args, &calldata->res.seq_res,
-                               1, task))
-               return;
-       rpc_call_start(task);
+                               1, task) != 0)
+               nfs_release_seqid(calldata->arg.seqid);
+       else
+               rpc_call_start(task);
 }
 
 static const struct rpc_call_ops nfs4_close_ops = {
@@ -4163,9 +4166,11 @@ 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, 1, task))
-               return;
-       rpc_call_start(task);
+                               &calldata->res.seq_res,
+                               1, task) != 0)
+               nfs_release_seqid(calldata->arg.seqid);
+       else
+               rpc_call_start(task);
 }
 
 static const struct rpc_call_ops nfs4_locku_ops = {
@@ -4309,7 +4314,7 @@ 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;
@@ -4318,10 +4323,15 @@ 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, 1, task))
+                               &data->res.seq_res,
+                               1, 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)