From 689cf5c15baf603a8041565ff0bd0d65d1634fd7 Mon Sep 17 00:00:00 2001
From: Alexandros Batsakis <batsakis@netapp.com>
Date: Mon, 14 Dec 2009 21:27:56 -0800
Subject: [PATCH] nfs: enforce FIFO ordering of operations trying to acquire
slot
Signed-off-by: Alexandros Batsakis <batsakis@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
fs/nfs/nfs4proc.c | 22 ++++++++++++++++++----
fs/nfs/nfs4state.c | 18 ++++++++++++++++--
net/sunrpc/sched.c | 1 +
3 files changed, 35 insertions(+), 6 deletions(-)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index acd698baf8eb..02513da9a016 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -346,8 +346,12 @@ nfs4_free_slot(struct nfs4_slot_table *tbl, u8 free_slotid)
*/
static void nfs41_check_drain_session_complete(struct nfs4_session *ses)
{
+ struct rpc_task *task;
+
if (!test_bit(NFS4CLNT_SESSION_DRAINING, &ses->clp->cl_state)) {
- rpc_wake_up_next(&ses->fc_slot_table.slot_tbl_waitq);
+ task = rpc_wake_up_next(&ses->fc_slot_table.slot_tbl_waitq);
+ if (task)
+ rpc_task_set_priority(task, RPC_PRIORITY_PRIVILEGED);
return;
}
@@ -483,6 +487,14 @@ static int nfs41_setup_sequence(struct nfs4_session *session,
return -EAGAIN;
}
+ if (!rpc_queue_empty(&tbl->slot_tbl_waitq) &&
+ !rpc_task_has_priority(task, RPC_PRIORITY_PRIVILEGED)) {
+ rpc_sleep_on(&tbl->slot_tbl_waitq, task, NULL);
+ spin_unlock(&tbl->slot_tbl_lock);
+ dprintk("%s enforce FIFO order\n", __func__);
+ return -EAGAIN;
+ }
+
slotid = nfs4_find_slot(tbl);
if (slotid == NFS4_MAX_SLOT_TABLE) {
rpc_sleep_on(&tbl->slot_tbl_waitq, task, NULL);
@@ -492,6 +504,7 @@ static int nfs41_setup_sequence(struct nfs4_session *session,
}
spin_unlock(&tbl->slot_tbl_lock);
+ rpc_task_set_priority(task, RPC_PRIORITY_NORMAL);
slot = tbl->slots + slotid;
args->sa_session = session;
args->sa_slotid = slotid;
@@ -4401,11 +4414,12 @@ static void nfs4_get_lease_time_prepare(struct rpc_task *task,
(struct nfs4_get_lease_time_data *)calldata;
dprintk("--> %s\n", __func__);
+ rpc_task_set_priority(task, RPC_PRIORITY_PRIVILEGED);
/* just setup sequence, do not trigger session recovery
since we're invoked within one */
ret = nfs41_setup_sequence(data->clp->cl_session,
- &data->args->la_seq_args,
- &data->res->lr_seq_res, 0, task);
+ &data->args->la_seq_args,
+ &data->res->lr_seq_res, 0, task);
BUG_ON(ret == -EAGAIN);
rpc_call_start(task);
@@ -4625,7 +4639,7 @@ struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp)
tbl = &session->fc_slot_table;
tbl->highest_used_slotid = -1;
spin_lock_init(&tbl->slot_tbl_lock);
- rpc_init_wait_queue(&tbl->slot_tbl_waitq, "ForeChannel Slot table");
+ rpc_init_priority_wait_queue(&tbl->slot_tbl_waitq, "ForeChannel Slot table");
tbl = &session->bc_slot_table;
tbl->highest_used_slotid = -1;
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index e76427e6346f..0e45075836b2 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -138,8 +138,22 @@ static int nfs41_setup_state_renewal(struct nfs_client *clp)
static void nfs41_end_drain_session(struct nfs_client *clp,
struct nfs4_session *ses)
{
- if (test_and_clear_bit(NFS4CLNT_SESSION_DRAINING, &clp->cl_state))
- rpc_wake_up(&ses->fc_slot_table.slot_tbl_waitq);
+ int max_slots;
+
+ if (test_and_clear_bit(NFS4CLNT_SESSION_DRAINING, &clp->cl_state)) {
+ spin_lock(&ses->fc_slot_table.slot_tbl_lock);
+ max_slots = ses->fc_slot_table.max_slots;
+ while (max_slots--) {
+ struct rpc_task *task;
+
+ task = rpc_wake_up_next(&ses->fc_slot_table.
+ slot_tbl_waitq);
+ if (!task)
+ break;
+ rpc_task_set_priority(task, RPC_PRIORITY_PRIVILEGED);
+ }
+ spin_unlock(&ses->fc_slot_table.slot_tbl_lock);
+ }
}
static int nfs41_begin_drain_session(struct nfs_client *clp,
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 89ea8e69ec78..aae6907fd546 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -210,6 +210,7 @@ void rpc_init_priority_wait_queue(struct rpc_wait_queue *queue, const char *qnam
{
__rpc_init_priority_wait_queue(queue, qname, RPC_NR_PRIORITY);
}
+EXPORT_SYMBOL_GPL(rpc_init_priority_wait_queue);
void rpc_init_wait_queue(struct rpc_wait_queue *queue, const char *qname)
{
--
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