| // 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->vl_probe; |
| struct afs_vlserver *server = call->vlserver; |
| struct afs_address *addr = &alist->addrs[call->probe_index]; |
| unsigned int server_index = call->server_index; |
| unsigned int rtt_us = 0; |
| unsigned int index = call->probe_index; |
| 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->probe_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->probe_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); |
| server->service_id = 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); |
| server->service_id = call->service_id; |
| } |
| } |
| |
| rtt_us = rxrpc_kernel_get_srtt(addr->peer); |
| 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); |
| |
| trace_afs_vl_probe(server, false, alist, index, call->error, call->abort_code, rtt_us); |
| _debug("probe [%u][%u] %pISpc rtt=%d ret=%d", |
| server_index, index, rxrpc_kernel_remote_addr(addr->peer), |
| 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_list *alist; |
| struct afs_call *call; |
| unsigned long unprobed; |
| unsigned int index, i; |
| bool in_progress = false; |
| int best_prio; |
| |
| _enter("%s", server->name); |
| |
| read_lock(&server->lock); |
| alist = rcu_dereference_protected(server->addresses, |
| lockdep_is_held(&server->lock)); |
| afs_get_addrlist(alist, afs_alist_trace_get_vlprobe); |
| read_unlock(&server->lock); |
| |
| atomic_set(&server->probe_outstanding, alist->nr_addrs); |
| memset(&server->probe, 0, sizeof(server->probe)); |
| server->probe.rtt = UINT_MAX; |
| |
| unprobed = (1UL << alist->nr_addrs) - 1; |
| while (unprobed) { |
| best_prio = -1; |
| index = 0; |
| 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_vl_probe(server, true, alist, index, 0, 0, 0); |
| call = afs_vl_get_capabilities(net, alist, index, key, server, |
| server_index); |
| if (!IS_ERR(call)) { |
| afs_prioritise_error(_e, call->error, call->abort_code); |
| afs_put_call(call); |
| in_progress = true; |
| } else { |
| afs_prioritise_error(_e, PTR_ERR(call), 0); |
| afs_done_one_vl_probe(server, false); |
| } |
| } |
| |
| afs_put_addrlist(alist, afs_alist_trace_put_vlprobe); |
| 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; |
| |
| 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; |
| } |