[ 36/80] NFS: Add sequence_priviliged_ops for nfs4_proc_sequence()

Greg Kroah-Hartman
2013-01-09T20:38:54Z

From: Bryan Schumaker <bjschuma@netapp.com>

commit 6bdb5f213c4344324f600dde885f25768fbd14db upstream.

If I mount an NFS v4.1 server to a single client multiple times and then
run xfstests over each mountpoint I usually get the client into a state
where recovery deadlocks. The server informs the client of a
cb_path_down sequence error, the client then does a
bind_connection_to_session and checks the status of the lease.

I found that bind_connection_to_session sets the NFS4_SESSION_DRAINING
flag on the client, but this flag is never unset before
nfs4_check_lease() reaches nfs4_proc_sequence(). This causes the client
to deadlock, halting all NFS activity to the server. nfs4_proc_sequence()
is only called by the state manager, so I can change it to run in privileged
mode to bypass the NFS4_SESSION_DRAINING check and avoid the deadlock.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/nfs/nfs4proc.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)

--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5739,13 +5739,26 @@ static void nfs41_sequence_prepare(struc
rpc_call_start(task);
}

+static void nfs41_sequence_prepare_privileged(struct rpc_task *task, void *data)
+{
+ rpc_task_set_priority(task, RPC_PRIORITY_PRIVILEGED);
+ nfs41_sequence_prepare(task, data);
+}
+
static const struct rpc_call_ops nfs41_sequence_ops = {
.rpc_call_done = nfs41_sequence_call_done,
.rpc_call_prepare = nfs41_sequence_prepare,
.rpc_release = nfs41_sequence_release,
};

-static struct rpc_task *_nfs41_proc_sequence(struct nfs_client *clp, struct rpc_cred *cred)
+static const struct rpc_call_ops nfs41_sequence_privileged_ops = {
+ .rpc_call_done = nfs41_sequence_call_done,
+ .rpc_call_prepare = nfs41_sequence_prepare_privileged,
+ .rpc_release = nfs41_sequence_release,
+};
+
+static struct rpc_task *_nfs41_proc_sequence(struct nfs_client *clp, struct rpc_cred *cred,
+ const struct rpc_call_ops *seq_ops)
{
struct nfs4_sequence_data *calldata;
struct rpc_message msg = {
@@ -5755,7 +5768,7 @@ static struct rpc_task *_nfs41_proc_sequ
struct rpc_task_setup task_setup_data = {
.rpc_client = clp->cl_rpcclient,
.rpc_message = &msg,
- .callback_ops = &nfs41_sequence_ops,
+ .callback_ops = seq_ops,
.flags = RPC_TASK_ASYNC | RPC_TASK_SOFT,
};

@@ -5782,7 +5795,7 @@ static int nfs41_proc_async_sequence(str

if ((renew_flags & NFS4_RENEW_TIMEOUT) == 0)
return 0;
- task = _nfs41_proc_sequence(clp, cred);
+ task = _nfs41_proc_sequence(clp, cred, &nfs41_sequence_ops);
if (IS_ERR(task))
ret = PTR_ERR(task);
else
@@ -5796,7 +5809,7 @@ static int nfs4_proc_sequence(struct nfs
struct rpc_task *task;
int ret;

- task = _nfs41_proc_sequence(clp, cred);
+ task = _nfs41_proc_sequence(clp, cred, &nfs41_sequence_privileged_ops);
if (IS_ERR(task)) {
ret = PTR_ERR(task);
goto out;