afs: Mark address lists with configured priorities

Add a field to each address in an address list (afs_addr_list struct) that
records the current priority for that address according to the address
preference table.  We don't want to do this every time we use an address
list, so the version number of the address preference table is recorded in
the address list too and we only re-mark the list when we see the version
change.

These numbers are then displayed through /proc/net/afs/servers.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org

diff --git a/fs/afs/addr_prefs.c b/fs/afs/addr_prefs.c
index c6dcff4f8aa1f6e38186a11f17b3d2f2f78264c8..a189ff8a5034e07d73b4f7d43134b85e6594cfee 100644 (file)
--- a/fs/afs/addr_prefs.c
+++ b/fs/afs/addr_prefs.c
@@ -447,3 +447,85 @@ inval:
        ret = -EINVAL;
        goto done;
 }
+
+/*
+ * Mark the priorities on an address list if the address preferences table has
+ * changed.  The caller must hold the RCU read lock.
+ */
+void afs_get_address_preferences_rcu(struct afs_net *net, struct afs_addr_list *alist)
+{
+       const struct afs_addr_preference_list *preflist =
+               rcu_dereference(net->address_prefs);
+       const struct sockaddr_in6 *sin6;
+       const struct sockaddr_in *sin;
+       const struct sockaddr *sa;
+       struct afs_addr_preference test;
+       enum cmp_ret cmp;
+       int i, j;
+
+       if (!preflist || !preflist->nr || !alist->nr_addrs ||
+           smp_load_acquire(&alist->addr_pref_version) == preflist->version)
+               return;
+
+       test.family = AF_INET;
+       test.subnet_mask = 32;
+       test.prio = 0;
+       for (i = 0; i < alist->nr_ipv4; i++) {
+               sa = rxrpc_kernel_remote_addr(alist->addrs[i].peer);
+               sin = (const struct sockaddr_in *)sa;
+               test.ipv4_addr = sin->sin_addr;
+               for (j = 0; j < preflist->ipv6_off; j++) {
+                       cmp = afs_cmp_address_pref(&test, &preflist->prefs[j]);
+                       switch (cmp) {
+                       case CONTINUE_SEARCH:
+                               continue;
+                       case INSERT_HERE:
+                               break;
+                       case EXACT_MATCH:
+                       case SUBNET_MATCH:
+                               WRITE_ONCE(alist->addrs[i].prio, preflist->prefs[j].prio);
+                               break;
+                       }
+               }
+       }
+
+       test.family = AF_INET6;
+       test.subnet_mask = 128;
+       test.prio = 0;
+       for (; i < alist->nr_addrs; i++) {
+               sa = rxrpc_kernel_remote_addr(alist->addrs[i].peer);
+               sin6 = (const struct sockaddr_in6 *)sa;
+               test.ipv6_addr = sin6->sin6_addr;
+               for (j = preflist->ipv6_off; j < preflist->nr; j++) {
+                       cmp = afs_cmp_address_pref(&test, &preflist->prefs[j]);
+                       switch (cmp) {
+                       case CONTINUE_SEARCH:
+                               continue;
+                       case INSERT_HERE:
+                               break;
+                       case EXACT_MATCH:
+                       case SUBNET_MATCH:
+                               WRITE_ONCE(alist->addrs[i].prio, preflist->prefs[j].prio);
+                               break;
+                       }
+               }
+       }
+
+       smp_store_release(&alist->addr_pref_version, preflist->version);
+}
+
+/*
+ * Mark the priorities on an address list if the address preferences table has
+ * changed.  Avoid taking the RCU read lock if we can.
+ */
+void afs_get_address_preferences(struct afs_net *net, struct afs_addr_list *alist)
+{
+       if (!net->address_prefs ||
+           /* Load version before prefs */
+           smp_load_acquire(&net->address_pref_version) == alist->addr_pref_version)
+               return;
+
+       rcu_read_lock();
+       afs_get_address_preferences_rcu(net, alist);
+       rcu_read_unlock();
+}

diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 4445c734cdcd918196a37d77e737e8ad772bd363..9a1e151e77e7ef855d9c3878589b13cde0be56ed 100644 (file)
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -97,6 +97,7 @@ struct afs_addr_preference_list {
 struct afs_address {
        struct rxrpc_peer       *peer;
        short                   last_error;     /* Last error from this address */
+       u16                     prio;           /* Address priority */
 };
 
 /*
@@ -107,6 +108,7 @@ struct afs_addr_list {
        refcount_t              usage;
        u32                     version;        /* Version */
        unsigned int            debug_id;
+       unsigned int            addr_pref_version; /* Version of address preference list */
        unsigned char           max_addrs;
        unsigned char           nr_addrs;
        unsigned char           preferred;      /* Preferred address */
@@ -1010,6 +1012,8 @@ extern int afs_merge_fs_addr6(struct afs_net *net, struct afs_addr_list *addr,
  * addr_prefs.c
  */
 int afs_proc_addr_prefs_write(struct file *file, char *buf, size_t size);
+void afs_get_address_preferences_rcu(struct afs_net *net, struct afs_addr_list *alist);
+void afs_get_address_preferences(struct afs_net *net, struct afs_addr_list *alist);
 
 /*
  * callback.c

diff --git a/fs/afs/proc.c b/fs/afs/proc.c
index 2e63c99a4f1ee397db5ae14b575a65f0eb2367ef..944eb51e75a1cc5f1d884ebb590cf626d1cbab64 100644 (file)
--- a/fs/afs/proc.c
+++ b/fs/afs/proc.c
@@ -447,17 +447,18 @@ static int afs_proc_servers_show(struct seq_file *m, void *v)
                   (int)(jiffies - server->probed_at) / HZ,
                   atomic_read(&server->probe_outstanding));
        failed = alist->probe_failed;
-       seq_printf(m, "  - ALIST v=%u rsp=%lx f=%lx\n",
-                  alist->version, alist->responded, alist->probe_failed);
+       seq_printf(m, "  - ALIST v=%u rsp=%lx f=%lx ap=%u\n",
+                  alist->version, alist->responded, alist->probe_failed,
+                  alist->addr_pref_version);
        for (i = 0; i < alist->nr_addrs; i++) {
                const struct afs_address *addr = &alist->addrs[i];
 
-               seq_printf(m, "    [%x] %pISpc%s rtt=%d err=%d\n",
+               seq_printf(m, "    [%x] %pISpc%s rtt=%d err=%d p=%u\n",
                           i, rxrpc_kernel_remote_addr(addr->peer),
                           alist->preferred == i ? "*" :
                           test_bit(i, &failed) ? "!" : "",
                           rxrpc_kernel_get_srtt(addr->peer),
-                          addr->last_error);
+                          addr->last_error, addr->prio);
        }
        return 0;
 }