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-rw-r--r--fs/afs/vl_probe.c292
1 files changed, 292 insertions, 0 deletions
diff --git a/fs/afs/vl_probe.c b/fs/afs/vl_probe.c
new file mode 100644
index 000000000..58452b86e
--- /dev/null
+++ b/fs/afs/vl_probe.c
@@ -0,0 +1,292 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* AFS vlserver probing
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include "afs_fs.h"
+#include "internal.h"
+#include "protocol_yfs.h"
+
+
+/*
+ * Handle the completion of a set of probes.
+ */
+static void afs_finished_vl_probe(struct afs_vlserver *server)
+{
+ if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)) {
+ server->rtt = UINT_MAX;
+ clear_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags);
+ }
+
+ clear_bit_unlock(AFS_VLSERVER_FL_PROBING, &server->flags);
+ wake_up_bit(&server->flags, AFS_VLSERVER_FL_PROBING);
+}
+
+/*
+ * Handle the completion of a probe RPC call.
+ */
+static void afs_done_one_vl_probe(struct afs_vlserver *server, bool wake_up)
+{
+ if (atomic_dec_and_test(&server->probe_outstanding)) {
+ afs_finished_vl_probe(server);
+ wake_up = true;
+ }
+
+ if (wake_up)
+ wake_up_all(&server->probe_wq);
+}
+
+/*
+ * Process the result of probing a vlserver. This is called after successful
+ * or failed delivery of an VL.GetCapabilities operation.
+ */
+void afs_vlserver_probe_result(struct afs_call *call)
+{
+ struct afs_addr_list *alist = call->alist;
+ struct afs_vlserver *server = call->vlserver;
+ unsigned int server_index = call->server_index;
+ unsigned int rtt_us = 0;
+ unsigned int index = call->addr_ix;
+ bool have_result = false;
+ int ret = call->error;
+
+ _enter("%s,%u,%u,%d,%d", server->name, server_index, index, ret, call->abort_code);
+
+ spin_lock(&server->probe_lock);
+
+ switch (ret) {
+ case 0:
+ server->probe.error = 0;
+ goto responded;
+ case -ECONNABORTED:
+ if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)) {
+ server->probe.abort_code = call->abort_code;
+ server->probe.error = ret;
+ }
+ goto responded;
+ case -ENOMEM:
+ case -ENONET:
+ case -EKEYEXPIRED:
+ case -EKEYREVOKED:
+ case -EKEYREJECTED:
+ server->probe.flags |= AFS_VLSERVER_PROBE_LOCAL_FAILURE;
+ if (server->probe.error == 0)
+ server->probe.error = ret;
+ trace_afs_io_error(call->debug_id, ret, afs_io_error_vl_probe_fail);
+ goto out;
+ case -ECONNRESET: /* Responded, but call expired. */
+ case -ERFKILL:
+ case -EADDRNOTAVAIL:
+ case -ENETUNREACH:
+ case -EHOSTUNREACH:
+ case -EHOSTDOWN:
+ case -ECONNREFUSED:
+ case -ETIMEDOUT:
+ case -ETIME:
+ default:
+ clear_bit(index, &alist->responded);
+ set_bit(index, &alist->failed);
+ if (!(server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED) &&
+ (server->probe.error == 0 ||
+ server->probe.error == -ETIMEDOUT ||
+ server->probe.error == -ETIME))
+ server->probe.error = ret;
+ trace_afs_io_error(call->debug_id, ret, afs_io_error_vl_probe_fail);
+ goto out;
+ }
+
+responded:
+ set_bit(index, &alist->responded);
+ clear_bit(index, &alist->failed);
+
+ if (call->service_id == YFS_VL_SERVICE) {
+ server->probe.flags |= AFS_VLSERVER_PROBE_IS_YFS;
+ set_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags);
+ alist->addrs[index].srx_service = call->service_id;
+ } else {
+ server->probe.flags |= AFS_VLSERVER_PROBE_NOT_YFS;
+ if (!(server->probe.flags & AFS_VLSERVER_PROBE_IS_YFS)) {
+ clear_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags);
+ alist->addrs[index].srx_service = call->service_id;
+ }
+ }
+
+ rxrpc_kernel_get_srtt(call->net->socket, call->rxcall, &rtt_us);
+ if (rtt_us < server->probe.rtt) {
+ server->probe.rtt = rtt_us;
+ server->rtt = rtt_us;
+ alist->preferred = index;
+ }
+
+ smp_wmb(); /* Set rtt before responded. */
+ server->probe.flags |= AFS_VLSERVER_PROBE_RESPONDED;
+ set_bit(AFS_VLSERVER_FL_PROBED, &server->flags);
+ set_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags);
+ have_result = true;
+out:
+ spin_unlock(&server->probe_lock);
+
+ _debug("probe [%u][%u] %pISpc rtt=%u ret=%d",
+ server_index, index, &alist->addrs[index].transport, rtt_us, ret);
+
+ afs_done_one_vl_probe(server, have_result);
+}
+
+/*
+ * Probe all of a vlserver's addresses to find out the best route and to
+ * query its capabilities.
+ */
+static bool afs_do_probe_vlserver(struct afs_net *net,
+ struct afs_vlserver *server,
+ struct key *key,
+ unsigned int server_index,
+ struct afs_error *_e)
+{
+ struct afs_addr_cursor ac = {
+ .index = 0,
+ };
+ struct afs_call *call;
+ bool in_progress = false;
+
+ _enter("%s", server->name);
+
+ read_lock(&server->lock);
+ ac.alist = rcu_dereference_protected(server->addresses,
+ lockdep_is_held(&server->lock));
+ read_unlock(&server->lock);
+
+ atomic_set(&server->probe_outstanding, ac.alist->nr_addrs);
+ memset(&server->probe, 0, sizeof(server->probe));
+ server->probe.rtt = UINT_MAX;
+
+ for (ac.index = 0; ac.index < ac.alist->nr_addrs; ac.index++) {
+ call = afs_vl_get_capabilities(net, &ac, key, server,
+ server_index);
+ if (!IS_ERR(call)) {
+ afs_put_call(call);
+ in_progress = true;
+ } else {
+ afs_prioritise_error(_e, PTR_ERR(call), ac.abort_code);
+ afs_done_one_vl_probe(server, false);
+ }
+ }
+
+ return in_progress;
+}
+
+/*
+ * Send off probes to all unprobed servers.
+ */
+int afs_send_vl_probes(struct afs_net *net, struct key *key,
+ struct afs_vlserver_list *vllist)
+{
+ struct afs_vlserver *server;
+ struct afs_error e;
+ bool in_progress = false;
+ int i;
+
+ e.error = 0;
+ e.responded = false;
+ for (i = 0; i < vllist->nr_servers; i++) {
+ server = vllist->servers[i].server;
+ if (test_bit(AFS_VLSERVER_FL_PROBED, &server->flags))
+ continue;
+
+ if (!test_and_set_bit_lock(AFS_VLSERVER_FL_PROBING, &server->flags) &&
+ afs_do_probe_vlserver(net, server, key, i, &e))
+ in_progress = true;
+ }
+
+ return in_progress ? 0 : e.error;
+}
+
+/*
+ * Wait for the first as-yet untried server to respond.
+ */
+int afs_wait_for_vl_probes(struct afs_vlserver_list *vllist,
+ unsigned long untried)
+{
+ struct wait_queue_entry *waits;
+ struct afs_vlserver *server;
+ unsigned int rtt = UINT_MAX, rtt_s;
+ bool have_responders = false;
+ int pref = -1, i;
+
+ _enter("%u,%lx", vllist->nr_servers, untried);
+
+ /* Only wait for servers that have a probe outstanding. */
+ for (i = 0; i < vllist->nr_servers; i++) {
+ if (test_bit(i, &untried)) {
+ server = vllist->servers[i].server;
+ if (!test_bit(AFS_VLSERVER_FL_PROBING, &server->flags))
+ __clear_bit(i, &untried);
+ if (server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)
+ have_responders = true;
+ }
+ }
+ if (have_responders || !untried)
+ return 0;
+
+ waits = kmalloc(array_size(vllist->nr_servers, sizeof(*waits)), GFP_KERNEL);
+ if (!waits)
+ return -ENOMEM;
+
+ for (i = 0; i < vllist->nr_servers; i++) {
+ if (test_bit(i, &untried)) {
+ server = vllist->servers[i].server;
+ init_waitqueue_entry(&waits[i], current);
+ add_wait_queue(&server->probe_wq, &waits[i]);
+ }
+ }
+
+ for (;;) {
+ bool still_probing = false;
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ for (i = 0; i < vllist->nr_servers; i++) {
+ if (test_bit(i, &untried)) {
+ server = vllist->servers[i].server;
+ if (server->probe.flags & AFS_VLSERVER_PROBE_RESPONDED)
+ goto stop;
+ if (test_bit(AFS_VLSERVER_FL_PROBING, &server->flags))
+ still_probing = true;
+ }
+ }
+
+ if (!still_probing || signal_pending(current))
+ goto stop;
+ schedule();
+ }
+
+stop:
+ set_current_state(TASK_RUNNING);
+
+ for (i = 0; i < vllist->nr_servers; i++) {
+ if (test_bit(i, &untried)) {
+ server = vllist->servers[i].server;
+ rtt_s = READ_ONCE(server->rtt);
+ if (test_bit(AFS_VLSERVER_FL_RESPONDING, &server->flags) &&
+ rtt_s < rtt) {
+ pref = i;
+ rtt = rtt_s;
+ }
+
+ remove_wait_queue(&server->probe_wq, &waits[i]);
+ }
+ }
+
+ kfree(waits);
+
+ if (pref == -1 && signal_pending(current))
+ return -ERESTARTSYS;
+
+ if (pref >= 0)
+ vllist->preferred = pref;
+
+ _leave(" = 0 [%u]", pref);
+ return 0;
+}