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-----BEGIN PGP SIGNATURE----- iQIVAwUAXRyW8vu3V2unywtrAQIhsw//cVtxLx4ZCox5Z/93cdqych8RoCrwcUEG Cli0NAjlp/0HETvCsIqdkPKf+4OYCW1tHB2KTdbFdQLZptLgoEhykx89k70z9ggb ViieEa1GvAKhdamVqkPUC+3Q33uzyRaK7Gi5N3phJoaO+o328SlrPG0LerQgY0Np Rf3je56A1gIjEgWTmpStxiY262jlgaR3IuvpOqbu2G0TQVWV8CsBKw61fTdmEEQp dIkNO/xFXS+PvPdmQe5zCAjD/W2D+ggeBMbBwHF411qA60plGinubBYKZ98ikliZ OnQQPExI7mroIMzpYT+rzEQyxui2nz5t+Hj+d6t7iIvitNcX/Q53sVTq3RfQ0FjG QCd+j/l2p7fkXK4Sxgb/UBkj/pRr6W+FYSbQ/tmpD8UypEf5B3ln6GuA6yTMuNRF wVb744slKWq0c7KUuXmz806B2qJoyFG206jyFnoByvs6cPmB1+JqhBBYOKHcwjbo HIK+oUKkEfE6ofjQ3B9xOQ1anfbRnjjfJCmXvns9v57y/nRP2P78HUJNnEsOolk2 nc3Ep41OgeZdwkts9KnSjmwy6VF3UZ2NQEiWXsUIOxGMtcodw9ci1bpquJ71oyut 4sFMJvMU4eJD+XuCOlAgpbTaQ0Wuf11kFpl1Cof4fj0Z09C25Ahj6iKEKnumtO+4 edfNLlwO6oo= =wgib -----END PGP SIGNATURE----- Merge tag 'afs-next-20190628' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull afs updates from David Howells: "A set of minor changes for AFS: - Remove an unnecessary check in afs_unlink() - Add a tracepoint for tracking callback management - Add a tracepoint for afs_server object usage - Use struct_size() - Add mappings for AFS UAE abort codes to Linux error codes, using symbolic names rather than hex numbers in the .c file" * tag 'afs-next-20190628' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: afs: Add support for the UAE error table fs/afs: use struct_size() in kzalloc() afs: Trace afs_server usage afs: Add some callback management tracepoints afs: afs_unlink() doesn't need to check dentry->d_inode
622 lines
15 KiB
C
622 lines
15 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* AFS server record management
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*
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* Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include "afs_fs.h"
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#include "internal.h"
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#include "protocol_yfs.h"
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static unsigned afs_server_gc_delay = 10; /* Server record timeout in seconds */
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static unsigned afs_server_update_delay = 30; /* Time till VLDB recheck in secs */
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static atomic_t afs_server_debug_id;
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static void afs_inc_servers_outstanding(struct afs_net *net)
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{
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atomic_inc(&net->servers_outstanding);
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}
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static void afs_dec_servers_outstanding(struct afs_net *net)
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{
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if (atomic_dec_and_test(&net->servers_outstanding))
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wake_up_var(&net->servers_outstanding);
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}
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/*
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* Find a server by one of its addresses.
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*/
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struct afs_server *afs_find_server(struct afs_net *net,
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const struct sockaddr_rxrpc *srx)
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{
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const struct sockaddr_in6 *a = &srx->transport.sin6, *b;
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const struct afs_addr_list *alist;
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struct afs_server *server = NULL;
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unsigned int i;
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bool ipv6 = true;
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int seq = 0, diff;
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if (srx->transport.sin6.sin6_addr.s6_addr32[0] == 0 ||
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srx->transport.sin6.sin6_addr.s6_addr32[1] == 0 ||
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srx->transport.sin6.sin6_addr.s6_addr32[2] == htonl(0xffff))
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ipv6 = false;
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rcu_read_lock();
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do {
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if (server)
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afs_put_server(net, server, afs_server_trace_put_find_rsq);
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server = NULL;
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read_seqbegin_or_lock(&net->fs_addr_lock, &seq);
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if (ipv6) {
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hlist_for_each_entry_rcu(server, &net->fs_addresses6, addr6_link) {
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alist = rcu_dereference(server->addresses);
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for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) {
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b = &alist->addrs[i].transport.sin6;
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diff = ((u16 __force)a->sin6_port -
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(u16 __force)b->sin6_port);
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if (diff == 0)
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diff = memcmp(&a->sin6_addr,
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&b->sin6_addr,
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sizeof(struct in6_addr));
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if (diff == 0)
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goto found;
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}
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}
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} else {
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hlist_for_each_entry_rcu(server, &net->fs_addresses4, addr4_link) {
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alist = rcu_dereference(server->addresses);
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for (i = 0; i < alist->nr_ipv4; i++) {
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b = &alist->addrs[i].transport.sin6;
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diff = ((u16 __force)a->sin6_port -
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(u16 __force)b->sin6_port);
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if (diff == 0)
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diff = ((u32 __force)a->sin6_addr.s6_addr32[3] -
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(u32 __force)b->sin6_addr.s6_addr32[3]);
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if (diff == 0)
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goto found;
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}
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}
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}
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server = NULL;
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found:
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if (server && !atomic_inc_not_zero(&server->usage))
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server = NULL;
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} while (need_seqretry(&net->fs_addr_lock, seq));
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done_seqretry(&net->fs_addr_lock, seq);
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rcu_read_unlock();
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return server;
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}
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/*
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* Look up a server by its UUID
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*/
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struct afs_server *afs_find_server_by_uuid(struct afs_net *net, const uuid_t *uuid)
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{
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struct afs_server *server = NULL;
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struct rb_node *p;
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int diff, seq = 0;
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_enter("%pU", uuid);
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do {
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/* Unfortunately, rbtree walking doesn't give reliable results
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* under just the RCU read lock, so we have to check for
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* changes.
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*/
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if (server)
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afs_put_server(net, server, afs_server_trace_put_uuid_rsq);
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server = NULL;
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read_seqbegin_or_lock(&net->fs_lock, &seq);
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p = net->fs_servers.rb_node;
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while (p) {
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server = rb_entry(p, struct afs_server, uuid_rb);
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diff = memcmp(uuid, &server->uuid, sizeof(*uuid));
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if (diff < 0) {
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p = p->rb_left;
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} else if (diff > 0) {
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p = p->rb_right;
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} else {
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afs_get_server(server, afs_server_trace_get_by_uuid);
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break;
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}
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server = NULL;
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}
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} while (need_seqretry(&net->fs_lock, seq));
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done_seqretry(&net->fs_lock, seq);
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_leave(" = %p", server);
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return server;
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}
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/*
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* Install a server record in the namespace tree
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*/
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static struct afs_server *afs_install_server(struct afs_net *net,
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struct afs_server *candidate)
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{
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const struct afs_addr_list *alist;
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struct afs_server *server;
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struct rb_node **pp, *p;
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int ret = -EEXIST, diff;
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_enter("%p", candidate);
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write_seqlock(&net->fs_lock);
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/* Firstly install the server in the UUID lookup tree */
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pp = &net->fs_servers.rb_node;
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p = NULL;
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while (*pp) {
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p = *pp;
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_debug("- consider %p", p);
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server = rb_entry(p, struct afs_server, uuid_rb);
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diff = memcmp(&candidate->uuid, &server->uuid, sizeof(uuid_t));
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if (diff < 0)
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pp = &(*pp)->rb_left;
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else if (diff > 0)
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pp = &(*pp)->rb_right;
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else
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goto exists;
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}
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server = candidate;
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rb_link_node(&server->uuid_rb, p, pp);
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rb_insert_color(&server->uuid_rb, &net->fs_servers);
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hlist_add_head_rcu(&server->proc_link, &net->fs_proc);
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write_seqlock(&net->fs_addr_lock);
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alist = rcu_dereference_protected(server->addresses,
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lockdep_is_held(&net->fs_addr_lock.lock));
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/* Secondly, if the server has any IPv4 and/or IPv6 addresses, install
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* it in the IPv4 and/or IPv6 reverse-map lists.
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*
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* TODO: For speed we want to use something other than a flat list
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* here; even sorting the list in terms of lowest address would help a
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* bit, but anything we might want to do gets messy and memory
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* intensive.
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*/
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if (alist->nr_ipv4 > 0)
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hlist_add_head_rcu(&server->addr4_link, &net->fs_addresses4);
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if (alist->nr_addrs > alist->nr_ipv4)
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hlist_add_head_rcu(&server->addr6_link, &net->fs_addresses6);
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write_sequnlock(&net->fs_addr_lock);
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ret = 0;
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exists:
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afs_get_server(server, afs_server_trace_get_install);
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write_sequnlock(&net->fs_lock);
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return server;
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}
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/*
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* allocate a new server record
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*/
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static struct afs_server *afs_alloc_server(struct afs_net *net,
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const uuid_t *uuid,
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struct afs_addr_list *alist)
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{
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struct afs_server *server;
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_enter("");
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server = kzalloc(sizeof(struct afs_server), GFP_KERNEL);
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if (!server)
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goto enomem;
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atomic_set(&server->usage, 1);
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server->debug_id = atomic_inc_return(&afs_server_debug_id);
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RCU_INIT_POINTER(server->addresses, alist);
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server->addr_version = alist->version;
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server->uuid = *uuid;
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server->update_at = ktime_get_real_seconds() + afs_server_update_delay;
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rwlock_init(&server->fs_lock);
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INIT_HLIST_HEAD(&server->cb_volumes);
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rwlock_init(&server->cb_break_lock);
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init_waitqueue_head(&server->probe_wq);
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spin_lock_init(&server->probe_lock);
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afs_inc_servers_outstanding(net);
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trace_afs_server(server, 1, afs_server_trace_alloc);
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_leave(" = %p", server);
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return server;
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enomem:
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_leave(" = NULL [nomem]");
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return NULL;
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}
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/*
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* Look up an address record for a server
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*/
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static struct afs_addr_list *afs_vl_lookup_addrs(struct afs_cell *cell,
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struct key *key, const uuid_t *uuid)
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{
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struct afs_vl_cursor vc;
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struct afs_addr_list *alist = NULL;
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int ret;
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ret = -ERESTARTSYS;
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if (afs_begin_vlserver_operation(&vc, cell, key)) {
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while (afs_select_vlserver(&vc)) {
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if (test_bit(AFS_VLSERVER_FL_IS_YFS, &vc.server->flags))
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alist = afs_yfsvl_get_endpoints(&vc, uuid);
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else
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alist = afs_vl_get_addrs_u(&vc, uuid);
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}
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ret = afs_end_vlserver_operation(&vc);
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}
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return ret < 0 ? ERR_PTR(ret) : alist;
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}
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/*
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* Get or create a fileserver record.
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*/
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struct afs_server *afs_lookup_server(struct afs_cell *cell, struct key *key,
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const uuid_t *uuid)
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{
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struct afs_addr_list *alist;
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struct afs_server *server, *candidate;
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_enter("%p,%pU", cell->net, uuid);
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server = afs_find_server_by_uuid(cell->net, uuid);
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if (server)
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return server;
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alist = afs_vl_lookup_addrs(cell, key, uuid);
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if (IS_ERR(alist))
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return ERR_CAST(alist);
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candidate = afs_alloc_server(cell->net, uuid, alist);
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if (!candidate) {
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afs_put_addrlist(alist);
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return ERR_PTR(-ENOMEM);
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}
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server = afs_install_server(cell->net, candidate);
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if (server != candidate) {
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afs_put_addrlist(alist);
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kfree(candidate);
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}
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_leave(" = %p{%d}", server, atomic_read(&server->usage));
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return server;
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}
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/*
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* Set the server timer to fire after a given delay, assuming it's not already
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* set for an earlier time.
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*/
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static void afs_set_server_timer(struct afs_net *net, time64_t delay)
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{
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if (net->live) {
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afs_inc_servers_outstanding(net);
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if (timer_reduce(&net->fs_timer, jiffies + delay * HZ))
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afs_dec_servers_outstanding(net);
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}
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}
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/*
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* Server management timer. We have an increment on fs_outstanding that we
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* need to pass along to the work item.
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*/
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void afs_servers_timer(struct timer_list *timer)
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{
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struct afs_net *net = container_of(timer, struct afs_net, fs_timer);
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_enter("");
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if (!queue_work(afs_wq, &net->fs_manager))
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afs_dec_servers_outstanding(net);
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}
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/*
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* Get a reference on a server object.
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*/
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struct afs_server *afs_get_server(struct afs_server *server,
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enum afs_server_trace reason)
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{
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unsigned int u = atomic_inc_return(&server->usage);
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trace_afs_server(server, u, reason);
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return server;
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}
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/*
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* Release a reference on a server record.
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*/
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void afs_put_server(struct afs_net *net, struct afs_server *server,
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enum afs_server_trace reason)
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{
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unsigned int usage;
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if (!server)
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return;
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server->put_time = ktime_get_real_seconds();
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usage = atomic_dec_return(&server->usage);
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trace_afs_server(server, usage, reason);
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if (likely(usage > 0))
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return;
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afs_set_server_timer(net, afs_server_gc_delay);
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}
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static void afs_server_rcu(struct rcu_head *rcu)
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{
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struct afs_server *server = container_of(rcu, struct afs_server, rcu);
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trace_afs_server(server, atomic_read(&server->usage),
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afs_server_trace_free);
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afs_put_addrlist(rcu_access_pointer(server->addresses));
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kfree(server);
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}
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/*
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* destroy a dead server
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*/
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static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
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{
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struct afs_addr_list *alist = rcu_access_pointer(server->addresses);
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struct afs_addr_cursor ac = {
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.alist = alist,
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.index = alist->preferred,
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.error = 0,
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};
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trace_afs_server(server, atomic_read(&server->usage),
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afs_server_trace_give_up_cb);
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if (test_bit(AFS_SERVER_FL_MAY_HAVE_CB, &server->flags))
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afs_fs_give_up_all_callbacks(net, server, &ac, NULL);
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wait_var_event(&server->probe_outstanding,
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atomic_read(&server->probe_outstanding) == 0);
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trace_afs_server(server, atomic_read(&server->usage),
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afs_server_trace_destroy);
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call_rcu(&server->rcu, afs_server_rcu);
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afs_dec_servers_outstanding(net);
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}
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/*
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* Garbage collect any expired servers.
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*/
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static void afs_gc_servers(struct afs_net *net, struct afs_server *gc_list)
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{
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struct afs_server *server;
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bool deleted;
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int usage;
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while ((server = gc_list)) {
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gc_list = server->gc_next;
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write_seqlock(&net->fs_lock);
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usage = 1;
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deleted = atomic_try_cmpxchg(&server->usage, &usage, 0);
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trace_afs_server(server, usage, afs_server_trace_gc);
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if (deleted) {
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rb_erase(&server->uuid_rb, &net->fs_servers);
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hlist_del_rcu(&server->proc_link);
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}
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write_sequnlock(&net->fs_lock);
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if (deleted) {
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write_seqlock(&net->fs_addr_lock);
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if (!hlist_unhashed(&server->addr4_link))
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hlist_del_rcu(&server->addr4_link);
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if (!hlist_unhashed(&server->addr6_link))
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hlist_del_rcu(&server->addr6_link);
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write_sequnlock(&net->fs_addr_lock);
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afs_destroy_server(net, server);
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}
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}
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}
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/*
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* Manage the records of servers known to be within a network namespace. This
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* includes garbage collecting unused servers.
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*
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* Note also that we were given an increment on net->servers_outstanding by
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* whoever queued us that we need to deal with before returning.
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*/
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void afs_manage_servers(struct work_struct *work)
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{
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struct afs_net *net = container_of(work, struct afs_net, fs_manager);
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struct afs_server *gc_list = NULL;
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struct rb_node *cursor;
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time64_t now = ktime_get_real_seconds(), next_manage = TIME64_MAX;
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bool purging = !net->live;
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_enter("");
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/* Trawl the server list looking for servers that have expired from
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* lack of use.
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*/
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read_seqlock_excl(&net->fs_lock);
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for (cursor = rb_first(&net->fs_servers); cursor; cursor = rb_next(cursor)) {
|
|
struct afs_server *server =
|
|
rb_entry(cursor, struct afs_server, uuid_rb);
|
|
int usage = atomic_read(&server->usage);
|
|
|
|
_debug("manage %pU %u", &server->uuid, usage);
|
|
|
|
ASSERTCMP(usage, >=, 1);
|
|
ASSERTIFCMP(purging, usage, ==, 1);
|
|
|
|
if (usage == 1) {
|
|
time64_t expire_at = server->put_time;
|
|
|
|
if (!test_bit(AFS_SERVER_FL_VL_FAIL, &server->flags) &&
|
|
!test_bit(AFS_SERVER_FL_NOT_FOUND, &server->flags))
|
|
expire_at += afs_server_gc_delay;
|
|
if (purging || expire_at <= now) {
|
|
server->gc_next = gc_list;
|
|
gc_list = server;
|
|
} else if (expire_at < next_manage) {
|
|
next_manage = expire_at;
|
|
}
|
|
}
|
|
}
|
|
|
|
read_sequnlock_excl(&net->fs_lock);
|
|
|
|
/* Update the timer on the way out. We have to pass an increment on
|
|
* servers_outstanding in the namespace that we are in to the timer or
|
|
* the work scheduler.
|
|
*/
|
|
if (!purging && next_manage < TIME64_MAX) {
|
|
now = ktime_get_real_seconds();
|
|
|
|
if (next_manage - now <= 0) {
|
|
if (queue_work(afs_wq, &net->fs_manager))
|
|
afs_inc_servers_outstanding(net);
|
|
} else {
|
|
afs_set_server_timer(net, next_manage - now);
|
|
}
|
|
}
|
|
|
|
afs_gc_servers(net, gc_list);
|
|
|
|
afs_dec_servers_outstanding(net);
|
|
_leave(" [%d]", atomic_read(&net->servers_outstanding));
|
|
}
|
|
|
|
static void afs_queue_server_manager(struct afs_net *net)
|
|
{
|
|
afs_inc_servers_outstanding(net);
|
|
if (!queue_work(afs_wq, &net->fs_manager))
|
|
afs_dec_servers_outstanding(net);
|
|
}
|
|
|
|
/*
|
|
* Purge list of servers.
|
|
*/
|
|
void afs_purge_servers(struct afs_net *net)
|
|
{
|
|
_enter("");
|
|
|
|
if (del_timer_sync(&net->fs_timer))
|
|
atomic_dec(&net->servers_outstanding);
|
|
|
|
afs_queue_server_manager(net);
|
|
|
|
_debug("wait");
|
|
wait_var_event(&net->servers_outstanding,
|
|
!atomic_read(&net->servers_outstanding));
|
|
_leave("");
|
|
}
|
|
|
|
/*
|
|
* Get an update for a server's address list.
|
|
*/
|
|
static noinline bool afs_update_server_record(struct afs_fs_cursor *fc, struct afs_server *server)
|
|
{
|
|
struct afs_addr_list *alist, *discard;
|
|
|
|
_enter("");
|
|
|
|
trace_afs_server(server, atomic_read(&server->usage), afs_server_trace_update);
|
|
|
|
alist = afs_vl_lookup_addrs(fc->vnode->volume->cell, fc->key,
|
|
&server->uuid);
|
|
if (IS_ERR(alist)) {
|
|
if ((PTR_ERR(alist) == -ERESTARTSYS ||
|
|
PTR_ERR(alist) == -EINTR) &&
|
|
!(fc->flags & AFS_FS_CURSOR_INTR) &&
|
|
server->addresses) {
|
|
_leave(" = t [intr]");
|
|
return true;
|
|
}
|
|
fc->error = PTR_ERR(alist);
|
|
_leave(" = f [%d]", fc->error);
|
|
return false;
|
|
}
|
|
|
|
discard = alist;
|
|
if (server->addr_version != alist->version) {
|
|
write_lock(&server->fs_lock);
|
|
discard = rcu_dereference_protected(server->addresses,
|
|
lockdep_is_held(&server->fs_lock));
|
|
rcu_assign_pointer(server->addresses, alist);
|
|
server->addr_version = alist->version;
|
|
write_unlock(&server->fs_lock);
|
|
}
|
|
|
|
server->update_at = ktime_get_real_seconds() + afs_server_update_delay;
|
|
afs_put_addrlist(discard);
|
|
_leave(" = t");
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* See if a server's address list needs updating.
|
|
*/
|
|
bool afs_check_server_record(struct afs_fs_cursor *fc, struct afs_server *server)
|
|
{
|
|
time64_t now = ktime_get_real_seconds();
|
|
long diff;
|
|
bool success;
|
|
int ret, retries = 0;
|
|
|
|
_enter("");
|
|
|
|
ASSERT(server);
|
|
|
|
retry:
|
|
diff = READ_ONCE(server->update_at) - now;
|
|
if (diff > 0) {
|
|
_leave(" = t [not now %ld]", diff);
|
|
return true;
|
|
}
|
|
|
|
if (!test_and_set_bit_lock(AFS_SERVER_FL_UPDATING, &server->flags)) {
|
|
success = afs_update_server_record(fc, server);
|
|
clear_bit_unlock(AFS_SERVER_FL_UPDATING, &server->flags);
|
|
wake_up_bit(&server->flags, AFS_SERVER_FL_UPDATING);
|
|
_leave(" = %d", success);
|
|
return success;
|
|
}
|
|
|
|
ret = wait_on_bit(&server->flags, AFS_SERVER_FL_UPDATING,
|
|
TASK_INTERRUPTIBLE);
|
|
if (ret == -ERESTARTSYS) {
|
|
if (!(fc->flags & AFS_FS_CURSOR_INTR) && server->addresses) {
|
|
_leave(" = t [intr]");
|
|
return true;
|
|
}
|
|
fc->error = ret;
|
|
_leave(" = f [intr]");
|
|
return false;
|
|
}
|
|
|
|
retries++;
|
|
if (retries == 4) {
|
|
_leave(" = f [stale]");
|
|
ret = -ESTALE;
|
|
return false;
|
|
}
|
|
goto retry;
|
|
}
|