| /* AFS vlserver probing |
| * |
| * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public Licence |
| * as published by the Free Software Foundation; either version |
| * 2 of the Licence, or (at your option) any later version. |
| */ |
| |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include "afs_fs.h" |
| #include "internal.h" |
| #include "protocol_yfs.h" |
| |
| static bool afs_vl_probe_done(struct afs_vlserver *server) |
| { |
| if (!atomic_dec_and_test(&server->probe_outstanding)) |
| return false; |
| |
| wake_up_var(&server->probe_outstanding); |
| clear_bit_unlock(AFS_VLSERVER_FL_PROBING, &server->flags); |
| wake_up_bit(&server->flags, AFS_VLSERVER_FL_PROBING); |
| return true; |
| } |
| |
| /* |
| * 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->reply[0]; |
| unsigned int server_index = (long)call->reply[1]; |
| unsigned int index = call->addr_ix; |
| unsigned int rtt = UINT_MAX; |
| bool have_result = false; |
| u64 _rtt; |
| 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.responded) { |
| server->probe.abort_code = call->abort_code; |
| server->probe.error = ret; |
| } |
| goto responded; |
| case -ENOMEM: |
| case -ENONET: |
| server->probe.local_failure = true; |
| afs_io_error(call, 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.responded && |
| (server->probe.error == 0 || |
| server->probe.error == -ETIMEDOUT || |
| server->probe.error == -ETIME)) |
| server->probe.error = ret; |
| afs_io_error(call, 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.is_yfs = true; |
| set_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags); |
| alist->addrs[index].srx_service = call->service_id; |
| } else { |
| server->probe.not_yfs = true; |
| if (!server->probe.is_yfs) { |
| clear_bit(AFS_VLSERVER_FL_IS_YFS, &server->flags); |
| alist->addrs[index].srx_service = call->service_id; |
| } |
| } |
| |
| /* Get the RTT and scale it to fit into a 32-bit value that represents |
| * over a minute of time so that we can access it with one instruction |
| * on a 32-bit system. |
| */ |
| _rtt = rxrpc_kernel_get_rtt(call->net->socket, call->rxcall); |
| _rtt /= 64; |
| rtt = (_rtt > UINT_MAX) ? UINT_MAX : _rtt; |
| if (rtt < server->probe.rtt) { |
| server->probe.rtt = rtt; |
| alist->preferred = index; |
| have_result = true; |
| } |
| |
| smp_wmb(); /* Set rtt before responded. */ |
| server->probe.responded = true; |
| set_bit(AFS_VLSERVER_FL_PROBED, &server->flags); |
| out: |
| spin_unlock(&server->probe_lock); |
| |
| _debug("probe [%u][%u] %pISpc rtt=%u ret=%d", |
| server_index, index, &alist->addrs[index].transport, |
| (unsigned int)rtt, ret); |
| |
| have_result |= afs_vl_probe_done(server); |
| if (have_result) { |
| server->probe.have_result = true; |
| wake_up_var(&server->probe.have_result); |
| wake_up_all(&server->probe_wq); |
| } |
| } |
| |
| /* |
| * 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); |
| } |
| } |
| |
| if (!in_progress) |
| afs_vl_probe_done(server); |
| 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; |
| 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.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.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; |
| if (server->probe.responded && |
| server->probe.rtt < rtt) { |
| pref = i; |
| rtt = server->probe.rtt; |
| } |
| |
| 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; |
| } |