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NFSv4: don't require lock for get_renew_cred or get_machine_cred

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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@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
NeilBrown 2018-12-03 11:30:30 +11:00 • committed by Anna Schumaker
parent a534ecb013
commit f15e1e8bc6
4 changed files with 16 additions and 25 deletions
Download patch file Download diff file Expand all files Collapse all files

26
fs/nfs/nfs4state.c
View file

@ -164,7 +164,7 @@ out:
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;