nfsd4: allow nfs4 state startup to fail
[safe/jmp/linux-2.6] / net / netfilter / nf_conntrack_core.c
index b54c234..b5869b9 100644 (file)
@@ -39,6 +39,7 @@
 #include <net/netfilter/nf_conntrack_core.h>
 #include <net/netfilter/nf_conntrack_extend.h>
 #include <net/netfilter/nf_conntrack_acct.h>
+#include <net/netfilter/nf_conntrack_ecache.h>
 #include <net/netfilter/nf_nat.h>
 #include <net/netfilter/nf_nat_core.h>
 
@@ -182,10 +183,6 @@ destroy_conntrack(struct nf_conntrack *nfct)
        NF_CT_ASSERT(atomic_read(&nfct->use) == 0);
        NF_CT_ASSERT(!timer_pending(&ct->timeout));
 
-       if (!test_bit(IPS_DYING_BIT, &ct->status))
-               nf_conntrack_event(IPCT_DESTROY, ct);
-       set_bit(IPS_DYING_BIT, &ct->status);
-
        /* To make sure we don't get any weird locking issues here:
         * destroy_conntrack() MUST NOT be called with a write lock
         * to nf_conntrack_lock!!! -HW */
@@ -219,27 +216,70 @@ destroy_conntrack(struct nf_conntrack *nfct)
        nf_conntrack_free(ct);
 }
 
-static void death_by_timeout(unsigned long ul_conntrack)
+void nf_ct_delete_from_lists(struct nf_conn *ct)
 {
-       struct nf_conn *ct = (void *)ul_conntrack;
        struct net *net = nf_ct_net(ct);
-       struct nf_conn_help *help = nfct_help(ct);
-       struct nf_conntrack_helper *helper;
-
-       if (help) {
-               rcu_read_lock();
-               helper = rcu_dereference(help->helper);
-               if (helper && helper->destroy)
-                       helper->destroy(ct);
-               rcu_read_unlock();
-       }
 
+       nf_ct_helper_destroy(ct);
        spin_lock_bh(&nf_conntrack_lock);
        /* Inside lock so preempt is disabled on module removal path.
         * Otherwise we can get spurious warnings. */
        NF_CT_STAT_INC(net, delete_list);
        clean_from_lists(ct);
        spin_unlock_bh(&nf_conntrack_lock);
+}
+EXPORT_SYMBOL_GPL(nf_ct_delete_from_lists);
+
+static void death_by_event(unsigned long ul_conntrack)
+{
+       struct nf_conn *ct = (void *)ul_conntrack;
+       struct net *net = nf_ct_net(ct);
+
+       if (nf_conntrack_event(IPCT_DESTROY, ct) < 0) {
+               /* bad luck, let's retry again */
+               ct->timeout.expires = jiffies +
+                       (random32() % net->ct.sysctl_events_retry_timeout);
+               add_timer(&ct->timeout);
+               return;
+       }
+       /* we've got the event delivered, now it's dying */
+       set_bit(IPS_DYING_BIT, &ct->status);
+       spin_lock(&nf_conntrack_lock);
+       hlist_nulls_del(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
+       spin_unlock(&nf_conntrack_lock);
+       nf_ct_put(ct);
+}
+
+void nf_ct_insert_dying_list(struct nf_conn *ct)
+{
+       struct net *net = nf_ct_net(ct);
+
+       /* add this conntrack to the dying list */
+       spin_lock_bh(&nf_conntrack_lock);
+       hlist_nulls_add_head(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode,
+                            &net->ct.dying);
+       spin_unlock_bh(&nf_conntrack_lock);
+       /* set a new timer to retry event delivery */
+       setup_timer(&ct->timeout, death_by_event, (unsigned long)ct);
+       ct->timeout.expires = jiffies +
+               (random32() % net->ct.sysctl_events_retry_timeout);
+       add_timer(&ct->timeout);
+}
+EXPORT_SYMBOL_GPL(nf_ct_insert_dying_list);
+
+static void death_by_timeout(unsigned long ul_conntrack)
+{
+       struct nf_conn *ct = (void *)ul_conntrack;
+
+       if (!test_bit(IPS_DYING_BIT, &ct->status) &&
+           unlikely(nf_conntrack_event(IPCT_DESTROY, ct) < 0)) {
+               /* destroy event was not delivered */
+               nf_ct_delete_from_lists(ct);
+               nf_ct_insert_dying_list(ct);
+               return;
+       }
+       set_bit(IPS_DYING_BIT, &ct->status);
+       nf_ct_delete_from_lists(ct);
        nf_ct_put(ct);
 }
 
@@ -295,7 +335,8 @@ begin:
        h = __nf_conntrack_find(net, tuple);
        if (h) {
                ct = nf_ct_tuplehash_to_ctrack(h);
-               if (unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
+               if (unlikely(nf_ct_is_dying(ct) ||
+                            !atomic_inc_not_zero(&ct->ct_general.use)))
                        h = NULL;
                else {
                        if (unlikely(!nf_ct_tuple_equal(tuple, &h->tuple))) {
@@ -385,7 +426,6 @@ __nf_conntrack_confirm(struct sk_buff *skb)
        /* Remove from unconfirmed list */
        hlist_nulls_del_rcu(&ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode);
 
-       __nf_conntrack_hash_insert(ct, hash, repl_hash);
        /* Timer relative to confirmation time, not original
           setting time, otherwise we'd get timer wrap in
           weird delay cases. */
@@ -393,8 +433,16 @@ __nf_conntrack_confirm(struct sk_buff *skb)
        add_timer(&ct->timeout);
        atomic_inc(&ct->ct_general.use);
        set_bit(IPS_CONFIRMED_BIT, &ct->status);
+
+       /* Since the lookup is lockless, hash insertion must be done after
+        * starting the timer and setting the CONFIRMED bit. The RCU barriers
+        * guarantee that no other CPU can find the conntrack before the above
+        * stores are visible.
+        */
+       __nf_conntrack_hash_insert(ct, hash, repl_hash);
        NF_CT_STAT_INC(net, insert);
        spin_unlock_bh(&nf_conntrack_lock);
+
        help = nfct_help(ct);
        if (help && help->helper)
                nf_conntrack_event_cache(IPCT_HELPER, ct);
@@ -463,7 +511,8 @@ static noinline int early_drop(struct net *net, unsigned int hash)
                        cnt++;
                }
 
-               if (ct && unlikely(!atomic_inc_not_zero(&ct->ct_general.use)))
+               if (ct && unlikely(nf_ct_is_dying(ct) ||
+                                  !atomic_inc_not_zero(&ct->ct_general.use)))
                        ct = NULL;
                if (ct || cnt >= NF_CT_EVICTION_RANGE)
                        break;
@@ -512,22 +561,38 @@ struct nf_conn *nf_conntrack_alloc(struct net *net,
                }
        }
 
-       ct = kmem_cache_zalloc(nf_conntrack_cachep, gfp);
+       /*
+        * Do not use kmem_cache_zalloc(), as this cache uses
+        * SLAB_DESTROY_BY_RCU.
+        */
+       ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
        if (ct == NULL) {
                pr_debug("nf_conntrack_alloc: Can't alloc conntrack.\n");
                atomic_dec(&net->ct.count);
                return ERR_PTR(-ENOMEM);
        }
-
-       atomic_set(&ct->ct_general.use, 1);
+       /*
+        * Let ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.next
+        * and ct->tuplehash[IP_CT_DIR_REPLY].hnnode.next unchanged.
+        */
+       memset(&ct->tuplehash[IP_CT_DIR_MAX], 0,
+              sizeof(*ct) - offsetof(struct nf_conn, tuplehash[IP_CT_DIR_MAX]));
+       spin_lock_init(&ct->lock);
        ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
+       ct->tuplehash[IP_CT_DIR_ORIGINAL].hnnode.pprev = NULL;
        ct->tuplehash[IP_CT_DIR_REPLY].tuple = *repl;
+       ct->tuplehash[IP_CT_DIR_REPLY].hnnode.pprev = NULL;
        /* Don't set timer yet: wait for confirmation */
        setup_timer(&ct->timeout, death_by_timeout, (unsigned long)ct);
 #ifdef CONFIG_NET_NS
        ct->ct_net = net;
 #endif
 
+       /*
+        * changes to lookup keys must be done before setting refcnt to 1
+        */
+       smp_wmb();
+       atomic_set(&ct->ct_general.use, 1);
        return ct;
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_alloc);
@@ -576,6 +641,7 @@ init_conntrack(struct net *net,
        }
 
        nf_ct_acct_ext_add(ct, GFP_ATOMIC);
+       nf_ct_ecache_ext_add(ct, GFP_ATOMIC);
 
        spin_lock_bh(&nf_conntrack_lock);
        exp = nf_ct_find_expectation(net, tuple);
@@ -806,8 +872,6 @@ void __nf_ct_refresh_acct(struct nf_conn *ct,
        NF_CT_ASSERT(ct->timeout.data == (unsigned long)ct);
        NF_CT_ASSERT(skb);
 
-       spin_lock_bh(&nf_conntrack_lock);
-
        /* Only update if this is not a fixed timeout */
        if (test_bit(IPS_FIXED_TIMEOUT_BIT, &ct->status))
                goto acct;
@@ -821,11 +885,8 @@ void __nf_ct_refresh_acct(struct nf_conn *ct,
                /* Only update the timeout if the new timeout is at least
                   HZ jiffies from the old timeout. Need del_timer for race
                   avoidance (may already be dying). */
-               if (newtime - ct->timeout.expires >= HZ
-                   && del_timer(&ct->timeout)) {
-                       ct->timeout.expires = newtime;
-                       add_timer(&ct->timeout);
-               }
+               if (newtime - ct->timeout.expires >= HZ)
+                       mod_timer_pending(&ct->timeout, newtime);
        }
 
 acct:
@@ -834,13 +895,13 @@ acct:
 
                acct = nf_conn_acct_find(ct);
                if (acct) {
+                       spin_lock_bh(&ct->lock);
                        acct[CTINFO2DIR(ctinfo)].packets++;
                        acct[CTINFO2DIR(ctinfo)].bytes +=
                                skb->len - skb_network_offset(skb);
+                       spin_unlock_bh(&ct->lock);
                }
        }
-
-       spin_unlock_bh(&nf_conntrack_lock);
 }
 EXPORT_SYMBOL_GPL(__nf_ct_refresh_acct);
 
@@ -852,14 +913,14 @@ bool __nf_ct_kill_acct(struct nf_conn *ct,
        if (do_acct) {
                struct nf_conn_counter *acct;
 
-               spin_lock_bh(&nf_conntrack_lock);
                acct = nf_conn_acct_find(ct);
                if (acct) {
+                       spin_lock_bh(&ct->lock);
                        acct[CTINFO2DIR(ctinfo)].packets++;
                        acct[CTINFO2DIR(ctinfo)].bytes +=
                                skb->len - skb_network_offset(skb);
+                       spin_unlock_bh(&ct->lock);
                }
-               spin_unlock_bh(&nf_conntrack_lock);
        }
 
        if (del_timer(&ct->timeout)) {
@@ -993,11 +1054,13 @@ static int kill_report(struct nf_conn *i, void *data)
 {
        struct __nf_ct_flush_report *fr = (struct __nf_ct_flush_report *)data;
 
-       /* get_next_corpse sets the dying bit for us */
-       nf_conntrack_event_report(IPCT_DESTROY,
-                                 i,
-                                 fr->pid,
-                                 fr->report);
+       /* If we fail to deliver the event, death_by_timeout() will retry */
+       if (nf_conntrack_event_report(IPCT_DESTROY, i,
+                                     fr->pid, fr->report) < 0)
+               return 1;
+
+       /* Avoid the delivery of the destroy event in death_by_timeout(). */
+       set_bit(IPS_DYING_BIT, &i->status);
        return 1;
 }
 
@@ -1026,6 +1089,21 @@ void nf_conntrack_flush_report(struct net *net, u32 pid, int report)
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_flush_report);
 
+static void nf_ct_release_dying_list(void)
+{
+       struct nf_conntrack_tuple_hash *h;
+       struct nf_conn *ct;
+       struct hlist_nulls_node *n;
+
+       spin_lock_bh(&nf_conntrack_lock);
+       hlist_nulls_for_each_entry(h, n, &init_net.ct.dying, hnnode) {
+               ct = nf_ct_tuplehash_to_ctrack(h);
+               /* never fails to remove them, no listeners at this point */
+               nf_ct_kill(ct);
+       }
+       spin_unlock_bh(&nf_conntrack_lock);
+}
+
 static void nf_conntrack_cleanup_init_net(void)
 {
        nf_conntrack_helper_fini();
@@ -1035,10 +1113,9 @@ static void nf_conntrack_cleanup_init_net(void)
 
 static void nf_conntrack_cleanup_net(struct net *net)
 {
-       nf_ct_event_cache_flush(net);
-       nf_conntrack_ecache_fini(net);
  i_see_dead_people:
        nf_ct_iterate_cleanup(net, kill_all, NULL);
+       nf_ct_release_dying_list();
        if (atomic_read(&net->ct.count) != 0) {
                schedule();
                goto i_see_dead_people;
@@ -1049,6 +1126,7 @@ static void nf_conntrack_cleanup_net(struct net *net)
 
        nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
                             nf_conntrack_htable_size);
+       nf_conntrack_ecache_fini(net);
        nf_conntrack_acct_fini(net);
        nf_conntrack_expect_fini(net);
        free_percpu(net->ct.stat);
@@ -1213,20 +1291,24 @@ err_cache:
        return ret;
 }
 
+/*
+ * We need to use special "null" values, not used in hash table
+ */
+#define UNCONFIRMED_NULLS_VAL  ((1<<30)+0)
+#define DYING_NULLS_VAL                ((1<<30)+1)
+
 static int nf_conntrack_init_net(struct net *net)
 {
        int ret;
 
        atomic_set(&net->ct.count, 0);
-       INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, 0);
+       INIT_HLIST_NULLS_HEAD(&net->ct.unconfirmed, UNCONFIRMED_NULLS_VAL);
+       INIT_HLIST_NULLS_HEAD(&net->ct.dying, DYING_NULLS_VAL);
        net->ct.stat = alloc_percpu(struct ip_conntrack_stat);
        if (!net->ct.stat) {
                ret = -ENOMEM;
                goto err_stat;
        }
-       ret = nf_conntrack_ecache_init(net);
-       if (ret < 0)
-               goto err_ecache;
        net->ct.hash = nf_ct_alloc_hashtable(&nf_conntrack_htable_size,
                                             &net->ct.hash_vmalloc, 1);
        if (!net->ct.hash) {
@@ -1240,6 +1322,9 @@ static int nf_conntrack_init_net(struct net *net)
        ret = nf_conntrack_acct_init(net);
        if (ret < 0)
                goto err_acct;
+       ret = nf_conntrack_ecache_init(net);
+       if (ret < 0)
+               goto err_ecache;
 
        /* Set up fake conntrack:
            - to never be deleted, not in any hashes */
@@ -1252,14 +1337,14 @@ static int nf_conntrack_init_net(struct net *net)
 
        return 0;
 
+err_ecache:
+       nf_conntrack_acct_fini(net);
 err_acct:
        nf_conntrack_expect_fini(net);
 err_expect:
        nf_ct_free_hashtable(net->ct.hash, net->ct.hash_vmalloc,
                             nf_conntrack_htable_size);
 err_hash:
-       nf_conntrack_ecache_fini(net);
-err_ecache:
        free_percpu(net->ct.stat);
 err_stat:
        return ret;