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-rw-r--r--fs/afs/fs_probe.c539
1 files changed, 539 insertions, 0 deletions
diff --git a/fs/afs/fs_probe.c b/fs/afs/fs_probe.c
new file mode 100644
index 000000000000..e0030ac74ea0
--- /dev/null
+++ b/fs/afs/fs_probe.c
@@ -0,0 +1,539 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* AFS fileserver probing
+ *
+ * Copyright (C) 2018, 2020 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_afs.h"
+#include "protocol_yfs.h"
+
+static unsigned int afs_fs_probe_fast_poll_interval = 30 * HZ;
+static unsigned int afs_fs_probe_slow_poll_interval = 5 * 60 * HZ;
+
+struct afs_endpoint_state *afs_get_endpoint_state(struct afs_endpoint_state *estate,
+ enum afs_estate_trace where)
+{
+ if (estate) {
+ int r;
+
+ __refcount_inc(&estate->ref, &r);
+ trace_afs_estate(estate->server_id, estate->probe_seq, r, where);
+ }
+ return estate;
+}
+
+static void afs_endpoint_state_rcu(struct rcu_head *rcu)
+{
+ struct afs_endpoint_state *estate = container_of(rcu, struct afs_endpoint_state, rcu);
+
+ trace_afs_estate(estate->server_id, estate->probe_seq, refcount_read(&estate->ref),
+ afs_estate_trace_free);
+ afs_put_addrlist(estate->addresses, afs_alist_trace_put_estate);
+ kfree(estate);
+}
+
+void afs_put_endpoint_state(struct afs_endpoint_state *estate, enum afs_estate_trace where)
+{
+ if (estate) {
+ unsigned int server_id = estate->server_id, probe_seq = estate->probe_seq;
+ bool dead;
+ int r;
+
+ dead = __refcount_dec_and_test(&estate->ref, &r);
+ trace_afs_estate(server_id, probe_seq, r, where);
+ if (dead)
+ call_rcu(&estate->rcu, afs_endpoint_state_rcu);
+ }
+}
+
+/*
+ * Start the probe polling timer. We have to supply it with an inc on the
+ * outstanding server count.
+ */
+static void afs_schedule_fs_probe(struct afs_net *net,
+ struct afs_server *server, bool fast)
+{
+ unsigned long atj;
+
+ if (!net->live)
+ return;
+
+ atj = server->probed_at;
+ atj += fast ? afs_fs_probe_fast_poll_interval : afs_fs_probe_slow_poll_interval;
+
+ afs_inc_servers_outstanding(net);
+ if (timer_reduce(&net->fs_probe_timer, atj))
+ afs_dec_servers_outstanding(net);
+}
+
+/*
+ * Handle the completion of a set of probes.
+ */
+static void afs_finished_fs_probe(struct afs_net *net, struct afs_server *server,
+ struct afs_endpoint_state *estate)
+{
+ bool responded = test_bit(AFS_ESTATE_RESPONDED, &estate->flags);
+
+ write_seqlock(&net->fs_lock);
+ if (responded) {
+ list_add_tail(&server->probe_link, &net->fs_probe_slow);
+ } else {
+ server->rtt = UINT_MAX;
+ clear_bit(AFS_SERVER_FL_RESPONDING, &server->flags);
+ list_add_tail(&server->probe_link, &net->fs_probe_fast);
+ }
+
+ write_sequnlock(&net->fs_lock);
+
+ afs_schedule_fs_probe(net, server, !responded);
+}
+
+/*
+ * Handle the completion of a probe.
+ */
+static void afs_done_one_fs_probe(struct afs_net *net, struct afs_server *server,
+ struct afs_endpoint_state *estate)
+{
+ _enter("");
+
+ if (atomic_dec_and_test(&estate->nr_probing))
+ afs_finished_fs_probe(net, server, estate);
+
+ wake_up_all(&server->probe_wq);
+}
+
+/*
+ * Handle inability to send a probe due to ENOMEM when trying to allocate a
+ * call struct.
+ */
+static void afs_fs_probe_not_done(struct afs_net *net,
+ struct afs_server *server,
+ struct afs_endpoint_state *estate,
+ int index)
+{
+ _enter("");
+
+ trace_afs_io_error(0, -ENOMEM, afs_io_error_fs_probe_fail);
+ spin_lock(&server->probe_lock);
+
+ set_bit(AFS_ESTATE_LOCAL_FAILURE, &estate->flags);
+ if (estate->error == 0)
+ estate->error = -ENOMEM;
+
+ set_bit(index, &estate->failed_set);
+
+ spin_unlock(&server->probe_lock);
+ return afs_done_one_fs_probe(net, server, estate);
+}
+
+/*
+ * Process the result of probing a fileserver. This is called after successful
+ * or failed delivery of an FS.GetCapabilities operation.
+ */
+void afs_fileserver_probe_result(struct afs_call *call)
+{
+ struct afs_endpoint_state *estate = call->probe;
+ struct afs_addr_list *alist = estate->addresses;
+ struct afs_address *addr = &alist->addrs[call->probe_index];
+ struct afs_server *server = call->server;
+ unsigned int index = call->probe_index;
+ unsigned int rtt_us = -1, cap0;
+ int ret = call->error;
+
+ _enter("%pU,%u", &server->uuid, index);
+
+ WRITE_ONCE(addr->last_error, ret);
+
+ spin_lock(&server->probe_lock);
+
+ switch (ret) {
+ case 0:
+ estate->error = 0;
+ goto responded;
+ case -ECONNABORTED:
+ if (!test_bit(AFS_ESTATE_RESPONDED, &estate->flags)) {
+ estate->abort_code = call->abort_code;
+ estate->error = ret;
+ }
+ goto responded;
+ case -ENOMEM:
+ case -ENONET:
+ clear_bit(index, &estate->responsive_set);
+ set_bit(AFS_ESTATE_LOCAL_FAILURE, &estate->flags);
+ trace_afs_io_error(call->debug_id, ret, afs_io_error_fs_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, &estate->responsive_set);
+ set_bit(index, &estate->failed_set);
+ if (!test_bit(AFS_ESTATE_RESPONDED, &estate->flags) &&
+ (estate->error == 0 ||
+ estate->error == -ETIMEDOUT ||
+ estate->error == -ETIME))
+ estate->error = ret;
+ trace_afs_io_error(call->debug_id, ret, afs_io_error_fs_probe_fail);
+ goto out;
+ }
+
+responded:
+ clear_bit(index, &estate->failed_set);
+
+ if (call->service_id == YFS_FS_SERVICE) {
+ set_bit(AFS_ESTATE_IS_YFS, &estate->flags);
+ set_bit(AFS_SERVER_FL_IS_YFS, &server->flags);
+ server->service_id = call->service_id;
+ } else {
+ set_bit(AFS_ESTATE_NOT_YFS, &estate->flags);
+ if (!test_bit(AFS_ESTATE_IS_YFS, &estate->flags)) {
+ clear_bit(AFS_SERVER_FL_IS_YFS, &server->flags);
+ server->service_id = call->service_id;
+ }
+ cap0 = ntohl(call->tmp);
+ if (cap0 & AFS3_VICED_CAPABILITY_64BITFILES)
+ set_bit(AFS_SERVER_FL_HAS_FS64, &server->flags);
+ else
+ clear_bit(AFS_SERVER_FL_HAS_FS64, &server->flags);
+ }
+
+ rtt_us = rxrpc_kernel_get_srtt(addr->peer);
+ if (rtt_us < estate->rtt) {
+ estate->rtt = rtt_us;
+ server->rtt = rtt_us;
+ alist->preferred = index;
+ }
+
+ smp_wmb(); /* Set rtt before responded. */
+ set_bit(AFS_ESTATE_RESPONDED, &estate->flags);
+ set_bit(index, &estate->responsive_set);
+ set_bit(AFS_SERVER_FL_RESPONDING, &server->flags);
+out:
+ spin_unlock(&server->probe_lock);
+
+ trace_afs_fs_probe(server, false, estate, index, call->error, call->abort_code, rtt_us);
+ _debug("probe[%x] %pU [%u] %pISpc rtt=%d ret=%d",
+ estate->probe_seq, &server->uuid, index,
+ rxrpc_kernel_remote_addr(alist->addrs[index].peer),
+ rtt_us, ret);
+
+ return afs_done_one_fs_probe(call->net, server, estate);
+}
+
+/*
+ * Probe all of a fileserver's addresses to find out the best route and to
+ * query its capabilities.
+ */
+int afs_fs_probe_fileserver(struct afs_net *net, struct afs_server *server,
+ struct afs_addr_list *new_alist, struct key *key)
+{
+ struct afs_endpoint_state *estate, *old;
+ struct afs_addr_list *old_alist = NULL, *alist;
+ unsigned long unprobed;
+
+ _enter("%pU", &server->uuid);
+
+ estate = kzalloc(sizeof(*estate), GFP_KERNEL);
+ if (!estate)
+ return -ENOMEM;
+
+ refcount_set(&estate->ref, 2);
+ estate->server_id = server->debug_id;
+ estate->rtt = UINT_MAX;
+
+ write_lock(&server->fs_lock);
+
+ old = rcu_dereference_protected(server->endpoint_state,
+ lockdep_is_held(&server->fs_lock));
+ if (old) {
+ estate->responsive_set = old->responsive_set;
+ if (!new_alist)
+ new_alist = old->addresses;
+ }
+
+ if (old_alist != new_alist)
+ afs_set_peer_appdata(server, old_alist, new_alist);
+
+ estate->addresses = afs_get_addrlist(new_alist, afs_alist_trace_get_estate);
+ alist = estate->addresses;
+ estate->probe_seq = ++server->probe_counter;
+ atomic_set(&estate->nr_probing, alist->nr_addrs);
+
+ if (new_alist)
+ server->addr_version = new_alist->version;
+ rcu_assign_pointer(server->endpoint_state, estate);
+ write_unlock(&server->fs_lock);
+ if (old)
+ set_bit(AFS_ESTATE_SUPERSEDED, &old->flags);
+
+ trace_afs_estate(estate->server_id, estate->probe_seq, refcount_read(&estate->ref),
+ afs_estate_trace_alloc_probe);
+
+ afs_get_address_preferences(net, new_alist);
+
+ server->probed_at = jiffies;
+ unprobed = (1UL << alist->nr_addrs) - 1;
+ while (unprobed) {
+ unsigned int index = 0, i;
+ int best_prio = -1;
+
+ for (i = 0; i < alist->nr_addrs; i++) {
+ if (test_bit(i, &unprobed) &&
+ alist->addrs[i].prio > best_prio) {
+ index = i;
+ best_prio = alist->addrs[i].prio;
+ }
+ }
+ __clear_bit(index, &unprobed);
+
+ trace_afs_fs_probe(server, true, estate, index, 0, 0, 0);
+ if (!afs_fs_get_capabilities(net, server, estate, index, key))
+ afs_fs_probe_not_done(net, server, estate, index);
+ }
+
+ afs_put_endpoint_state(old, afs_estate_trace_put_probe);
+ afs_put_endpoint_state(estate, afs_estate_trace_put_probe);
+ return 0;
+}
+
+/*
+ * Wait for the first as-yet untried fileserver to respond, for the probe state
+ * to be superseded or for all probes to finish.
+ */
+int afs_wait_for_fs_probes(struct afs_operation *op, struct afs_server_state *states, bool intr)
+{
+ struct afs_endpoint_state *estate;
+ struct afs_server_list *slist = op->server_list;
+ bool still_probing = true;
+ int ret = 0, i;
+
+ _enter("%u", slist->nr_servers);
+
+ for (i = 0; i < slist->nr_servers; i++) {
+ estate = states[i].endpoint_state;
+ if (test_bit(AFS_ESTATE_SUPERSEDED, &estate->flags))
+ return 2;
+ if (atomic_read(&estate->nr_probing))
+ still_probing = true;
+ if (estate->responsive_set & states[i].untried_addrs)
+ return 1;
+ }
+ if (!still_probing)
+ return 0;
+
+ for (i = 0; i < slist->nr_servers; i++)
+ add_wait_queue(&slist->servers[i].server->probe_wq, &states[i].probe_waiter);
+
+ for (;;) {
+ still_probing = false;
+
+ set_current_state(intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
+ for (i = 0; i < slist->nr_servers; i++) {
+ estate = states[i].endpoint_state;
+ if (test_bit(AFS_ESTATE_SUPERSEDED, &estate->flags)) {
+ ret = 2;
+ goto stop;
+ }
+ if (atomic_read(&estate->nr_probing))
+ still_probing = true;
+ if (estate->responsive_set & states[i].untried_addrs) {
+ ret = 1;
+ goto stop;
+ }
+ }
+
+ if (!still_probing || signal_pending(current))
+ goto stop;
+ schedule();
+ }
+
+stop:
+ set_current_state(TASK_RUNNING);
+
+ for (i = 0; i < slist->nr_servers; i++)
+ remove_wait_queue(&slist->servers[i].server->probe_wq, &states[i].probe_waiter);
+
+ if (!ret && signal_pending(current))
+ ret = -ERESTARTSYS;
+ return ret;
+}
+
+/*
+ * Probe timer. We have an increment on fs_outstanding that we need to pass
+ * along to the work item.
+ */
+void afs_fs_probe_timer(struct timer_list *timer)
+{
+ struct afs_net *net = container_of(timer, struct afs_net, fs_probe_timer);
+
+ if (!net->live || !queue_work(afs_wq, &net->fs_prober))
+ afs_dec_servers_outstanding(net);
+}
+
+/*
+ * Dispatch a probe to a server.
+ */
+static void afs_dispatch_fs_probe(struct afs_net *net, struct afs_server *server)
+ __releases(&net->fs_lock)
+{
+ struct key *key = NULL;
+
+ /* We remove it from the queues here - it will be added back to
+ * one of the queues on the completion of the probe.
+ */
+ list_del_init(&server->probe_link);
+
+ afs_get_server(server, afs_server_trace_get_probe);
+ write_sequnlock(&net->fs_lock);
+
+ afs_fs_probe_fileserver(net, server, NULL, key);
+ afs_put_server(net, server, afs_server_trace_put_probe);
+}
+
+/*
+ * Probe a server immediately without waiting for its due time to come
+ * round. This is used when all of the addresses have been tried.
+ */
+void afs_probe_fileserver(struct afs_net *net, struct afs_server *server)
+{
+ write_seqlock(&net->fs_lock);
+ if (!list_empty(&server->probe_link))
+ return afs_dispatch_fs_probe(net, server);
+ write_sequnlock(&net->fs_lock);
+}
+
+/*
+ * Probe dispatcher to regularly dispatch probes to keep NAT alive.
+ */
+void afs_fs_probe_dispatcher(struct work_struct *work)
+{
+ struct afs_net *net = container_of(work, struct afs_net, fs_prober);
+ struct afs_server *fast, *slow, *server;
+ unsigned long nowj, timer_at, poll_at;
+ bool first_pass = true, set_timer = false;
+
+ if (!net->live) {
+ afs_dec_servers_outstanding(net);
+ return;
+ }
+
+ _enter("");
+
+ if (list_empty(&net->fs_probe_fast) && list_empty(&net->fs_probe_slow)) {
+ afs_dec_servers_outstanding(net);
+ _leave(" [none]");
+ return;
+ }
+
+again:
+ write_seqlock(&net->fs_lock);
+
+ fast = slow = server = NULL;
+ nowj = jiffies;
+ timer_at = nowj + MAX_JIFFY_OFFSET;
+
+ if (!list_empty(&net->fs_probe_fast)) {
+ fast = list_first_entry(&net->fs_probe_fast, struct afs_server, probe_link);
+ poll_at = fast->probed_at + afs_fs_probe_fast_poll_interval;
+ if (time_before(nowj, poll_at)) {
+ timer_at = poll_at;
+ set_timer = true;
+ fast = NULL;
+ }
+ }
+
+ if (!list_empty(&net->fs_probe_slow)) {
+ slow = list_first_entry(&net->fs_probe_slow, struct afs_server, probe_link);
+ poll_at = slow->probed_at + afs_fs_probe_slow_poll_interval;
+ if (time_before(nowj, poll_at)) {
+ if (time_before(poll_at, timer_at))
+ timer_at = poll_at;
+ set_timer = true;
+ slow = NULL;
+ }
+ }
+
+ server = fast ?: slow;
+ if (server)
+ _debug("probe %pU", &server->uuid);
+
+ if (server && (first_pass || !need_resched())) {
+ afs_dispatch_fs_probe(net, server);
+ first_pass = false;
+ goto again;
+ }
+
+ write_sequnlock(&net->fs_lock);
+
+ if (server) {
+ if (!queue_work(afs_wq, &net->fs_prober))
+ afs_dec_servers_outstanding(net);
+ _leave(" [requeue]");
+ } else if (set_timer) {
+ if (timer_reduce(&net->fs_probe_timer, timer_at))
+ afs_dec_servers_outstanding(net);
+ _leave(" [timer]");
+ } else {
+ afs_dec_servers_outstanding(net);
+ _leave(" [quiesce]");
+ }
+}
+
+/*
+ * Wait for a probe on a particular fileserver to complete for 2s.
+ */
+int afs_wait_for_one_fs_probe(struct afs_server *server, struct afs_endpoint_state *estate,
+ unsigned long exclude, bool is_intr)
+{
+ struct wait_queue_entry wait;
+ unsigned long timo = 2 * HZ;
+
+ if (atomic_read(&estate->nr_probing) == 0)
+ goto dont_wait;
+
+ init_wait_entry(&wait, 0);
+ for (;;) {
+ prepare_to_wait_event(&server->probe_wq, &wait,
+ is_intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
+ if (timo == 0 ||
+ test_bit(AFS_ESTATE_SUPERSEDED, &estate->flags) ||
+ (estate->responsive_set & ~exclude) ||
+ atomic_read(&estate->nr_probing) == 0 ||
+ (is_intr && signal_pending(current)))
+ break;
+ timo = schedule_timeout(timo);
+ }
+
+ finish_wait(&server->probe_wq, &wait);
+
+dont_wait:
+ if (test_bit(AFS_ESTATE_SUPERSEDED, &estate->flags))
+ return 0;
+ if (estate->responsive_set & ~exclude)
+ return 1;
+ if (is_intr && signal_pending(current))
+ return -ERESTARTSYS;
+ if (timo == 0)
+ return -ETIME;
+ return -EDESTADDRREQ;
+}
+
+/*
+ * Clean up the probing when the namespace is killed off.
+ */
+void afs_fs_probe_cleanup(struct afs_net *net)
+{
+ if (timer_delete_sync(&net->fs_probe_timer))
+ afs_dec_servers_outstanding(net);
+}
generated by cgit (git 2.34.1) at 2025-12-25 15:17:00 +0000