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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@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
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6
fs/nfs/nfs4_fs.h
View File

@ -250,7 +250,7 @@ struct nfs4_add_xprt_data {
struct nfs4_state_maintenance_ops { struct nfs4_state_maintenance_ops {
int (*sched_state_renewal)(struct nfs_client *, struct rpc_cred *, unsigned); 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 *); 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 */ /* nfs4state.c */
struct rpc_cred *nfs4_get_clid_cred(struct nfs_client *clp); 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_machine_cred(struct nfs_client *clp);
struct rpc_cred *nfs4_get_renew_cred_locked(struct nfs_client *clp); struct rpc_cred *nfs4_get_renew_cred(struct nfs_client *clp);
int nfs4_discover_server_trunking(struct nfs_client *clp, int nfs4_discover_server_trunking(struct nfs_client *clp,
struct nfs_client **); struct nfs_client **);
int nfs40_discover_server_trunking(struct nfs_client *clp, int nfs40_discover_server_trunking(struct nfs_client *clp,

4
fs/nfs/nfs4proc.c
View File

@ -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 = { static const struct nfs4_state_maintenance_ops nfs40_state_renewal_ops = {
.sched_state_renewal = nfs4_proc_async_renew, .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, .renew_lease = nfs4_proc_renew,
}; };
#if defined(CONFIG_NFS_V4_1) #if defined(CONFIG_NFS_V4_1)
static const struct nfs4_state_maintenance_ops nfs41_state_renewal_ops = { static const struct nfs4_state_maintenance_ops nfs41_state_renewal_ops = {
.sched_state_renewal = nfs41_proc_async_sequence, .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, .renew_lease = nfs4_proc_sequence,
}; };
#endif #endif

5
fs/nfs/nfs4renewd.c
View File

@ -68,7 +68,6 @@ nfs4_renew_state(struct work_struct *work)
if (test_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state)) if (test_bit(NFS_CS_STOP_RENEW, &clp->cl_res_state))
goto out; goto out;
spin_lock(&clp->cl_lock);
lease = clp->cl_lease_time; lease = clp->cl_lease_time;
last = clp->cl_last_renewal; last = clp->cl_last_renewal;
now = jiffies; now = jiffies;
@ -79,8 +78,7 @@ nfs4_renew_state(struct work_struct *work)
renew_flags |= NFS4_RENEW_DELEGATION_CB; renew_flags |= NFS4_RENEW_DELEGATION_CB;
if (renew_flags != 0) { if (renew_flags != 0) {
cred = ops->get_state_renewal_cred_locked(clp); cred = ops->get_state_renewal_cred(clp);
spin_unlock(&clp->cl_lock);
if (cred == NULL) { if (cred == NULL) {
if (!(renew_flags & NFS4_RENEW_DELEGATION_CB)) { if (!(renew_flags & NFS4_RENEW_DELEGATION_CB)) {
set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state); set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
@ -104,7 +102,6 @@ nfs4_renew_state(struct work_struct *work)
} else { } else {
dprintk("%s: failed to call renewd. Reason: lease not expired \n", dprintk("%s: failed to call renewd. Reason: lease not expired \n",
__func__); __func__);
spin_unlock(&clp->cl_lock);
} }
nfs4_schedule_state_renewal(clp); nfs4_schedule_state_renewal(clp);
out_exp: out_exp:

26
fs/nfs/nfs4state.c
View File

@ -164,7 +164,7 @@ out:
return status; 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; 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 * @clp: client state handle
* *
* Returns an rpc_cred with reference count bumped, or NULL. * Returns an rpc_cred with reference count bumped, or NULL.
* Caller must hold clp->cl_lock. * 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 rpc_cred *cred = NULL;
struct nfs_server *server; struct nfs_server *server;
/* Use machine credentials if available */ /* Use machine credentials if available */
cred = nfs4_get_machine_cred_locked(clp); cred = nfs4_get_machine_cred(clp);
if (cred != NULL) if (cred != NULL)
goto out; goto out;
spin_lock(&clp->cl_lock);
rcu_read_lock(); rcu_read_lock();
list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) { list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
cred = nfs4_get_renew_cred_server_locked(server); 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; break;
} }
rcu_read_unlock(); rcu_read_unlock();
spin_unlock(&clp->cl_lock);
out: out:
return cred; return cred;
@ -402,9 +404,7 @@ struct rpc_cred *nfs4_get_clid_cred(struct nfs_client *clp)
{ {
struct rpc_cred *cred; struct rpc_cred *cred;
spin_lock(&clp->cl_lock); cred = nfs4_get_machine_cred(clp);
cred = nfs4_get_machine_cred_locked(clp);
spin_unlock(&clp->cl_lock);
return cred; 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? */ /* Is the client already known to have an expired lease? */
if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state)) if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state))
return 0; return 0;
spin_lock(&clp->cl_lock); cred = ops->get_state_renewal_cred(clp);
cred = ops->get_state_renewal_cred_locked(clp);
spin_unlock(&clp->cl_lock);
if (cred == NULL) { if (cred == NULL) {
cred = nfs4_get_clid_cred(clp); cred = nfs4_get_clid_cred(clp);
status = -ENOKEY; status = -ENOKEY;
@ -2112,9 +2110,7 @@ static int nfs4_handle_migration(struct nfs_client *clp)
dprintk("%s: migration reported on \"%s\"\n", __func__, dprintk("%s: migration reported on \"%s\"\n", __func__,
clp->cl_hostname); clp->cl_hostname);
spin_lock(&clp->cl_lock); cred = ops->get_state_renewal_cred(clp);
cred = ops->get_state_renewal_cred_locked(clp);
spin_unlock(&clp->cl_lock);
if (cred == NULL) if (cred == NULL)
return -NFS4ERR_NOENT; 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__, dprintk("%s: lease moved reported on \"%s\"\n", __func__,
clp->cl_hostname); clp->cl_hostname);
spin_lock(&clp->cl_lock); cred = ops->get_state_renewal_cred(clp);
cred = ops->get_state_renewal_cred_locked(clp);
spin_unlock(&clp->cl_lock);
if (cred == NULL) if (cred == NULL)
return -NFS4ERR_NOENT; return -NFS4ERR_NOENT;