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nfsd4: don't destroy in-use session

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This changes session destruction to be similar to client destruction in
that attempts to destroy a session while in use (which should be rare
corner cases) result in DELAY.  This simplifies things somewhat and
helps meet a coming 4.2 requirement.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
J. Bruce Fields 2013-03-19 12:05:39 -04:00
parent 221a687669
commit 66b2b9b2b0
2 changed files with 43 additions and 33 deletions
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72
fs/nfsd/nfs4state.c
View File

@ -94,17 +94,32 @@ nfs4_lock_state(void)
mutex_lock(&client_mutex);
}
static void free_session(struct kref *);
static void free_session(struct nfsd4_session *);
/* Must be called under the client_lock */
static void nfsd4_put_session_locked(struct nfsd4_session *ses)
void nfsd4_put_session(struct nfsd4_session *ses)
{
kref_put(&ses->se_ref, free_session);
atomic_dec(&ses->se_ref);
}
static void nfsd4_get_session(struct nfsd4_session *ses)
static bool is_session_dead(struct nfsd4_session *ses)
{
kref_get(&ses->se_ref);
return ses->se_flags & NFS4_SESSION_DEAD;
}
static __be32 mark_session_dead_locked(struct nfsd4_session *ses)
{
if (atomic_read(&ses->se_ref))
return nfserr_jukebox;
ses->se_flags |= NFS4_SESSION_DEAD;
return nfs_ok;
}
static __be32 nfsd4_get_session_locked(struct nfsd4_session *ses)
{
if (is_session_dead(ses))
return nfserr_badsession;
atomic_inc(&ses->se_ref);
return nfs_ok;
}
void
@ -935,28 +950,15 @@ static void __free_session(struct nfsd4_session *ses)
kfree(ses);
}
static void free_session(struct kref *kref)
static void free_session(struct nfsd4_session *ses)
{
struct nfsd4_session *ses;
struct nfsd_net *nn;
ses = container_of(kref, struct nfsd4_session, se_ref);
nn = net_generic(ses->se_client->net, nfsd_net_id);
struct nfsd_net *nn = net_generic(ses->se_client->net, nfsd_net_id);
lockdep_assert_held(&nn->client_lock);
nfsd4_del_conns(ses);
__free_session(ses);
}
void nfsd4_put_session(struct nfsd4_session *ses)
{
struct nfsd_net *nn = net_generic(ses->se_client->net, nfsd_net_id);
spin_lock(&nn->client_lock);
nfsd4_put_session_locked(ses);
spin_unlock(&nn->client_lock);
}
static struct nfsd4_session *alloc_session(struct nfsd4_channel_attrs *fchan,
struct nfsd_net *nn)
{
@ -997,7 +999,7 @@ static void init_session(struct svc_rqst *rqstp, struct nfsd4_session *new, stru
new->se_flags = cses->flags;
new->se_cb_prog = cses->callback_prog;
new->se_cb_sec = cses->cb_sec;
kref_init(&new->se_ref);
atomic_set(&new->se_ref, 0);
idx = hash_sessionid(&new->se_sessionid);
spin_lock(&nn->client_lock);
list_add(&new->se_hash, &nn->sessionid_hashtbl[idx]);
@ -1095,7 +1097,8 @@ free_client(struct nfs4_client *clp)
ses = list_entry(clp->cl_sessions.next, struct nfsd4_session,
se_perclnt);
list_del(&ses->se_perclnt);
nfsd4_put_session_locked(ses);
WARN_ON_ONCE(atomic_read(&ses->se_ref));
free_session(ses);
}
free_svc_cred(&clp->cl_cred);
kfree(clp->cl_name.data);
@ -1976,15 +1979,16 @@ nfsd4_destroy_session(struct svc_rqst *r,
status = nfserr_badsession;
if (!ses)
goto out_client_lock;
status = mark_session_dead_locked(ses);
if (status)
goto out_client_lock;
unhash_session(ses);
spin_unlock(&nn->client_lock);
nfsd4_probe_callback_sync(ses->se_client);
spin_lock(&nn->client_lock);
nfsd4_del_conns(ses);
nfsd4_put_session_locked(ses);
free_session(ses);
status = nfs_ok;
out_client_lock:
spin_unlock(&nn->client_lock);
@ -2075,18 +2079,21 @@ nfsd4_sequence(struct svc_rqst *rqstp,
status = get_client_locked(clp);
if (status)
goto out_no_session;
status = nfsd4_get_session_locked(session);
if (status)
goto out_put_client;
status = nfserr_too_many_ops;
if (nfsd4_session_too_many_ops(rqstp, session))
goto out_put_client;
goto out_put_session;
status = nfserr_req_too_big;
if (nfsd4_request_too_big(rqstp, session))
goto out_put_client;
goto out_put_session;
status = nfserr_badslot;
if (seq->slotid >= session->se_fchannel.maxreqs)
goto out_put_client;
goto out_put_session;
slot = session->se_slots[seq->slotid];
dprintk("%s: slotid %d\n", __func__, seq->slotid);
@ -2101,7 +2108,7 @@ nfsd4_sequence(struct svc_rqst *rqstp,
if (status == nfserr_replay_cache) {
status = nfserr_seq_misordered;
if (!(slot->sl_flags & NFSD4_SLOT_INITIALIZED))
goto out_put_client;
goto out_put_session;
cstate->slot = slot;
cstate->session = session;
/* Return the cached reply status and set cstate->status
@ -2111,7 +2118,7 @@ nfsd4_sequence(struct svc_rqst *rqstp,
goto out;
}
if (status)
goto out_put_client;
goto out_put_session;
nfsd4_sequence_check_conn(conn, session);
conn = NULL;
@ -2128,7 +2135,6 @@ nfsd4_sequence(struct svc_rqst *rqstp,
cstate->session = session;
out:
nfsd4_get_session(cstate->session);
switch (clp->cl_cb_state) {
case NFSD4_CB_DOWN:
seq->status_flags = SEQ4_STATUS_CB_PATH_DOWN;
@ -2143,6 +2149,8 @@ out_no_session:
kfree(conn);
spin_unlock(&nn->client_lock);
return status;
out_put_session:
nfsd4_put_session(session);
out_put_client:
put_client_renew_locked(clp);
goto out_no_session;

4
fs/nfsd/state.h
View File

@ -194,9 +194,11 @@ struct nfsd4_conn {
};
struct nfsd4_session {
struct kref se_ref;
atomic_t se_ref;
struct list_head se_hash; /* hash by sessionid */
struct list_head se_perclnt;
/* See SESSION4_PERSIST, etc. for standard flags; this is internal-only: */
#define NFS4_SESSION_DEAD 0x010
u32 se_flags;
struct nfs4_client *se_client;
struct nfs4_sessionid se_sessionid;