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Date: Mon, 03 Dec 2018 11:30:30 +1100
From: NeilBrown <neilb@...e.com>
To: "J. Bruce Fields" <bfields@...ldses.org>,
Chuck Lever <chuck.lever@...cle.com>,
Jeff Layton <jlayton@...nel.org>,
Trond Myklebust <trond.myklebust@...merspace.com>,
Anna Schumaker <anna.schumaker@...app.com>
Cc: Linux NFS Mailing List <linux-nfs@...r.kernel.org>,
linux-kernel@...r.kernel.org
Subject: [PATCH 10/23] NFSv4: don't require lock for get_renew_cred or
get_machine_cred
This lock is no longer necessary.
If nfs4_get_renew_cred() needs to hunt through the open-state
creds for a user cred, it still takes the lock to stablize
the rbtree, but otherwise there are no races.
Note that this completely removes the lock from nfs4_renew_state().
It appears that the original need for the locking here was removed
long ago, and there is no longer anything to protect.
Signed-off-by: NeilBrown <neilb@...e.com>
---
fs/nfs/nfs4_fs.h | 6 +++---
fs/nfs/nfs4proc.c | 4 ++--
fs/nfs/nfs4renewd.c | 5 +----
fs/nfs/nfs4state.c | 26 ++++++++++----------------
4 files changed, 16 insertions(+), 25 deletions(-)
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index 1b994b527518..ad649a49822f 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -250,7 +250,7 @@ struct nfs4_add_xprt_data {
struct nfs4_state_maintenance_ops {
int (*sched_state_renewal)(struct nfs_client *, struct rpc_cred *, unsigned);
- struct rpc_cred * (*get_state_renewal_cred_locked)(struct nfs_client *);
+ struct rpc_cred * (*get_state_renewal_cred)(struct nfs_client *);
int (*renew_lease)(struct nfs_client *, struct rpc_cred *);
};
@@ -451,8 +451,8 @@ extern void nfs4_set_lease_period(struct nfs_client *clp,
/* nfs4state.c */
struct rpc_cred *nfs4_get_clid_cred(struct nfs_client *clp);
-struct rpc_cred *nfs4_get_machine_cred_locked(struct nfs_client *clp);
-struct rpc_cred *nfs4_get_renew_cred_locked(struct nfs_client *clp);
+struct rpc_cred *nfs4_get_machine_cred(struct nfs_client *clp);
+struct rpc_cred *nfs4_get_renew_cred(struct nfs_client *clp);
int nfs4_discover_server_trunking(struct nfs_client *clp,
struct nfs_client **);
int nfs40_discover_server_trunking(struct nfs_client *clp,
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 867457d6dfbe..cafa155a053e 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -9606,14 +9606,14 @@ static const struct nfs4_state_recovery_ops nfs41_nograce_recovery_ops = {
static const struct nfs4_state_maintenance_ops nfs40_state_renewal_ops = {
.sched_state_renewal = nfs4_proc_async_renew,
- .get_state_renewal_cred_locked = nfs4_get_renew_cred_locked,
+ .get_state_renewal_cred = nfs4_get_renew_cred,
.renew_lease = nfs4_proc_renew,
};
#if defined(CONFIG_NFS_V4_1)
static const struct nfs4_state_maintenance_ops nfs41_state_renewal_ops = {
.sched_state_renewal = nfs41_proc_async_sequence,
- .get_state_renewal_cred_locked = nfs4_get_machine_cred_locked,
+ .get_state_renewal_cred = nfs4_get_machine_cred,
.renew_lease = nfs4_proc_sequence,
};
#endif
diff --git a/fs/nfs/nfs4renewd.c b/fs/nfs/nfs4renewd.c
index 1f8c2ae43a8d..8880cd958210 100644
--- a/fs/nfs/nfs4renewd.c
+++ b/fs/nfs/nfs4renewd.c
@@ -68,7 +68,6 @@ nfs4_renew_state(struct work_struct *work)
if (test_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state))
goto out;
- spin_lock(&clp->cl_lock);
lease = clp->cl_lease_time;
last = clp->cl_last_renewal;
now = jiffies;
@@ -79,8 +78,7 @@ nfs4_renew_state(struct work_struct *work)
renew_flags |= NFS4_RENEW_DELEGATION_CB;
if (renew_flags != 0) {
- cred = ops->get_state_renewal_cred_locked(clp);
- spin_unlock(&clp->cl_lock);
+ cred = ops->get_state_renewal_cred(clp);
if (cred == NULL) {
if (!(renew_flags & NFS4_RENEW_DELEGATION_CB)) {
set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
@@ -104,7 +102,6 @@ nfs4_renew_state(struct work_struct *work)
} else {
dprintk("%s: failed to call renewd. Reason: lease not expired \n",
__func__);
- spin_unlock(&clp->cl_lock);
}
nfs4_schedule_state_renewal(clp);
out_exp:
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 511bcdee98f5..f142fca6995b 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -164,7 +164,7 @@ int nfs40_discover_server_trunking(struct nfs_client *clp,
return status;
}
-struct rpc_cred *nfs4_get_machine_cred_locked(struct nfs_client *clp)
+struct rpc_cred *nfs4_get_machine_cred(struct nfs_client *clp)
{
struct rpc_cred *cred = clp->cl_root_cred;
@@ -210,22 +210,23 @@ nfs4_get_renew_cred_server_locked(struct nfs_server *server)
}
/**
- * nfs4_get_renew_cred_locked - Acquire credential for a renew operation
+ * nfs4_get_renew_cred - Acquire credential for a renew operation
* @clp: client state handle
*
* Returns an rpc_cred with reference count bumped, or NULL.
* Caller must hold clp->cl_lock.
*/
-struct rpc_cred *nfs4_get_renew_cred_locked(struct nfs_client *clp)
+struct rpc_cred *nfs4_get_renew_cred(struct nfs_client *clp)
{
struct rpc_cred *cred = NULL;
struct nfs_server *server;
/* Use machine credentials if available */
- cred = nfs4_get_machine_cred_locked(clp);
+ cred = nfs4_get_machine_cred(clp);
if (cred != NULL)
goto out;
+ spin_lock(&clp->cl_lock);
rcu_read_lock();
list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
cred = nfs4_get_renew_cred_server_locked(server);
@@ -233,6 +234,7 @@ struct rpc_cred *nfs4_get_renew_cred_locked(struct nfs_client *clp)
break;
}
rcu_read_unlock();
+ spin_unlock(&clp->cl_lock);
out:
return cred;
@@ -402,9 +404,7 @@ struct rpc_cred *nfs4_get_clid_cred(struct nfs_client *clp)
{
struct rpc_cred *cred;
- spin_lock(&clp->cl_lock);
- cred = nfs4_get_machine_cred_locked(clp);
- spin_unlock(&clp->cl_lock);
+ cred = nfs4_get_machine_cred(clp);
return cred;
}
@@ -1908,9 +1908,7 @@ static int nfs4_check_lease(struct nfs_client *clp)
/* Is the client already known to have an expired lease? */
if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state))
return 0;
- spin_lock(&clp->cl_lock);
- cred = ops->get_state_renewal_cred_locked(clp);
- spin_unlock(&clp->cl_lock);
+ cred = ops->get_state_renewal_cred(clp);
if (cred == NULL) {
cred = nfs4_get_clid_cred(clp);
status = -ENOKEY;
@@ -2112,9 +2110,7 @@ static int nfs4_handle_migration(struct nfs_client *clp)
dprintk("%s: migration reported on \"%s\"\n", __func__,
clp->cl_hostname);
- spin_lock(&clp->cl_lock);
- cred = ops->get_state_renewal_cred_locked(clp);
- spin_unlock(&clp->cl_lock);
+ cred = ops->get_state_renewal_cred(clp);
if (cred == NULL)
return -NFS4ERR_NOENT;
@@ -2160,9 +2156,7 @@ static int nfs4_handle_lease_moved(struct nfs_client *clp)
dprintk("%s: lease moved reported on \"%s\"\n", __func__,
clp->cl_hostname);
- spin_lock(&clp->cl_lock);
- cred = ops->get_state_renewal_cred_locked(clp);
- spin_unlock(&clp->cl_lock);
+ cred = ops->get_state_renewal_cred(clp);
if (cred == NULL)
return -NFS4ERR_NOENT;
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