SUNRPC: Use RCU to dereference the rpc_clnt.cl_xprt field
A migration event will replace the rpc_xprt used by an rpc_clnt. To
ensure this can be done safely, all references to cl_xprt must now use
a form of rcu_dereference().
Special care is taken with rpc_peeraddr2str(), which returns a pointer
to memory whose lifetime is the same as the rpc_xprt.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
[ cel: fix lockdep splats and layering violations ]
[ cel: forward ported to 3.4 ]
[ cel: remove rpc_max_reqs(), add rpc_net_ns() ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 0e0865e..1bb2972 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -8,6 +8,7 @@
#include <linux/nfs4.h>
#include <linux/nfs_fs.h>
#include <linux/slab.h>
+#include <linux/rcupdate.h>
#include "nfs4_fs.h"
#include "callback.h"
#include "delegation.h"
@@ -33,7 +34,7 @@
res->bitmap[0] = res->bitmap[1] = 0;
res->status = htonl(NFS4ERR_BADHANDLE);
- dprintk("NFS: GETATTR callback request from %s\n",
+ dprintk_rcu("NFS: GETATTR callback request from %s\n",
rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
inode = nfs_delegation_find_inode(cps->clp, &args->fh);
@@ -73,7 +74,7 @@
if (!cps->clp) /* Always set for v4.0. Set in cb_sequence for v4.1 */
goto out;
- dprintk("NFS: RECALL callback request from %s\n",
+ dprintk_rcu("NFS: RECALL callback request from %s\n",
rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
res = htonl(NFS4ERR_BADHANDLE);
@@ -533,7 +534,7 @@
if (!cps->clp) /* set in cb_sequence */
goto out;
- dprintk("NFS: RECALL_ANY callback request from %s\n",
+ dprintk_rcu("NFS: RECALL_ANY callback request from %s\n",
rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR));
status = cpu_to_be32(NFS4ERR_INVAL);
@@ -568,7 +569,7 @@
if (!cps->clp) /* set in cb_sequence */
goto out;
- dprintk("NFS: CB_RECALL_SLOT request from %s target max slots %d\n",
+ dprintk_rcu("NFS: CB_RECALL_SLOT request from %s target max slots %d\n",
rpc_peeraddr2str(cps->clp->cl_rpcclient, RPC_DISPLAY_ADDR),
args->crsa_target_max_slots);
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 1506adf..d038dc5 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -1284,16 +1284,18 @@
int error;
if (clp->rpc_ops->version == 4) {
+ struct rpc_xprt *xprt;
+
+ xprt = rcu_dereference_raw(clp->cl_rpcclient->cl_xprt);
+
if (nfs4_has_session(clp)) {
- error = xprt_setup_backchannel(
- clp->cl_rpcclient->cl_xprt,
+ error = xprt_setup_backchannel(xprt,
NFS41_BC_MIN_CALLBACKS);
if (error < 0)
return error;
}
- error = nfs_callback_up(clp->cl_mvops->minor_version,
- clp->cl_rpcclient->cl_xprt);
+ error = nfs_callback_up(clp->cl_mvops->minor_version, xprt);
if (error < 0) {
dprintk("%s: failed to start callback. Error = %d\n",
__func__, error);
@@ -1678,7 +1680,7 @@
data->addrlen,
parent_client->cl_ipaddr,
data->authflavor,
- parent_server->client->cl_xprt->prot,
+ rpc_protocol(parent_server->client),
parent_server->client->cl_timeout,
parent_client->cl_mvops->minor_version,
parent_client->net);
@@ -1905,12 +1907,14 @@
if (clp->cl_cons_state != NFS_CS_READY)
return 0;
+ rcu_read_lock();
seq_printf(m, "v%u %s %s %3d %s\n",
clp->rpc_ops->version,
rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT),
atomic_read(&clp->cl_count),
clp->cl_hostname);
+ rcu_read_unlock();
return 0;
}
@@ -1993,6 +1997,7 @@
(unsigned long long) server->fsid.major,
(unsigned long long) server->fsid.minor);
+ rcu_read_lock();
seq_printf(m, "v%u %s %s %-7s %-17s %s\n",
clp->rpc_ops->version,
rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),
@@ -2000,6 +2005,7 @@
dev,
fsid,
nfs_server_fscache_state(server));
+ rcu_read_unlock();
return 0;
}
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 667ea74..9c8eca31 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -96,8 +96,8 @@
static size_t nfs_parse_server_name(char *string, size_t len,
struct sockaddr *sa, size_t salen, struct nfs_server *server)
{
+ struct net *net = rpc_net_ns(server->client);
ssize_t ret;
- struct net *net = server->client->cl_xprt->xprt_net;
ret = rpc_pton(net, string, len, sa, salen);
if (ret == 0) {
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 6c8e170..671510c 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3833,6 +3833,7 @@
*p = htonl((u32)clp->cl_boot_time.tv_nsec);
for(;;) {
+ rcu_read_lock();
setclientid.sc_name_len = scnprintf(setclientid.sc_name,
sizeof(setclientid.sc_name), "%s/%s %s %s %u",
clp->cl_ipaddr,
@@ -3849,6 +3850,7 @@
setclientid.sc_uaddr_len = scnprintf(setclientid.sc_uaddr,
sizeof(setclientid.sc_uaddr), "%s.%u.%u",
clp->cl_ipaddr, port >> 8, port & 255);
+ rcu_read_unlock();
status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
if (status != -NFS4ERR_CLID_INUSE)
@@ -5244,11 +5246,16 @@
void nfs4_destroy_session(struct nfs4_session *session)
{
+ struct rpc_xprt *xprt;
+
nfs4_proc_destroy_session(session);
+
+ rcu_read_lock();
+ xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt);
+ rcu_read_unlock();
dprintk("%s Destroy backchannel for xprt %p\n",
- __func__, session->clp->cl_rpcclient->cl_xprt);
- xprt_destroy_backchannel(session->clp->cl_rpcclient->cl_xprt,
- NFS41_BC_MIN_CALLBACKS);
+ __func__, xprt);
+ xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS);
nfs4_destroy_slot_tables(session);
kfree(session);
}
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index c1111a3..bae959e 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1037,19 +1037,28 @@
void nfs4_schedule_state_manager(struct nfs_client *clp)
{
struct task_struct *task;
+ char buf[INET6_ADDRSTRLEN + sizeof("-manager") + 1];
if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) != 0)
return;
__module_get(THIS_MODULE);
atomic_inc(&clp->cl_count);
- task = kthread_run(nfs4_run_state_manager, clp, "%s-manager",
- rpc_peeraddr2str(clp->cl_rpcclient,
- RPC_DISPLAY_ADDR));
- if (!IS_ERR(task))
- return;
- nfs4_clear_state_manager_bit(clp);
- nfs_put_client(clp);
- module_put(THIS_MODULE);
+
+ /* The rcu_read_lock() is not strictly necessary, as the state
+ * manager is the only thread that ever changes the rpc_xprt
+ * after it's initialized. At this point, we're single threaded. */
+ rcu_read_lock();
+ snprintf(buf, sizeof(buf), "%s-manager",
+ rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_ADDR));
+ rcu_read_unlock();
+ task = kthread_run(nfs4_run_state_manager, clp, buf);
+ if (IS_ERR(task)) {
+ printk(KERN_ERR "%s: kthread_run: %ld\n",
+ __func__, PTR_ERR(task));
+ nfs4_clear_state_manager_bit(clp);
+ nfs_put_client(clp);
+ module_put(THIS_MODULE);
+ }
}
/*
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index f4ccdae..7002be1 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -53,6 +53,7 @@
#include <linux/magic.h>
#include <linux/parser.h>
#include <linux/nsproxy.h>
+#include <linux/rcupdate.h>
#include <asm/system.h>
#include <asm/uaccess.h>
@@ -701,8 +702,10 @@
else
seq_puts(m, nfs_infop->nostr);
}
+ rcu_read_lock();
seq_printf(m, ",proto=%s",
rpc_peeraddr2str(nfss->client, RPC_DISPLAY_NETID));
+ rcu_read_unlock();
if (version == 4) {
if (nfss->port != NFS_PORT)
seq_printf(m, ",port=%u", nfss->port);
@@ -751,9 +754,11 @@
nfs_show_mount_options(m, nfss, 0);
+ rcu_read_lock();
seq_printf(m, ",addr=%s",
rpc_peeraddr2str(nfss->nfs_client->cl_rpcclient,
RPC_DISPLAY_ADDR));
+ rcu_read_unlock();
return 0;
}