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fs/afs/server.c
15.2 KB
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// 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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*/ #include <linux/sched.h> #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 */ 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) { atomic_inc(&net->servers_outstanding); } static void afs_dec_servers_outstanding(struct afs_net *net) { 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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/* * Find a server by one of its addresses. */ struct afs_server *afs_find_server(struct afs_net *net, const struct sockaddr_rxrpc *srx) |
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{ |
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const struct afs_addr_list *alist; struct afs_server *server = NULL; unsigned int i; |
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int seq = 0, diff; |
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rcu_read_lock(); do { if (server) |
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afs_put_server(net, server, afs_server_trace_put_find_rsq); |
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server = NULL; read_seqbegin_or_lock(&net->fs_addr_lock, &seq); |
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if (srx->transport.family == AF_INET6) { const struct sockaddr_in6 *a = &srx->transport.sin6, *b; |
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hlist_for_each_entry_rcu(server, &net->fs_addresses6, addr6_link) { alist = rcu_dereference(server->addresses); for (i = alist->nr_ipv4; i < alist->nr_addrs; i++) { b = &alist->addrs[i].transport.sin6; |
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diff = ((u16 __force)a->sin6_port - (u16 __force)b->sin6_port); |
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if (diff == 0) diff = memcmp(&a->sin6_addr, &b->sin6_addr, sizeof(struct in6_addr)); if (diff == 0) goto found; |
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} } } else { |
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const struct sockaddr_in *a = &srx->transport.sin, *b; |
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hlist_for_each_entry_rcu(server, &net->fs_addresses4, addr4_link) { alist = rcu_dereference(server->addresses); for (i = 0; i < alist->nr_ipv4; i++) { |
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b = &alist->addrs[i].transport.sin; diff = ((u16 __force)a->sin_port - (u16 __force)b->sin_port); |
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if (diff == 0) |
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diff = ((u32 __force)a->sin_addr.s_addr - (u32 __force)b->sin_addr.s_addr); |
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if (diff == 0) goto found; |
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} } } |
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server = NULL; found: if (server && !atomic_inc_not_zero(&server->usage)) server = NULL; } while (need_seqretry(&net->fs_addr_lock, seq)); done_seqretry(&net->fs_addr_lock, seq); rcu_read_unlock(); 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; struct rb_node *p; int diff, seq = 0; _enter("%pU", uuid); do { /* Unfortunately, rbtree walking doesn't give reliable results * under just the RCU read lock, so we have to check for * changes. */ if (server) |
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afs_put_server(net, server, afs_server_trace_put_uuid_rsq); |
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server = NULL; read_seqbegin_or_lock(&net->fs_lock, &seq); p = net->fs_servers.rb_node; while (p) { server = rb_entry(p, struct afs_server, uuid_rb); diff = memcmp(uuid, &server->uuid, sizeof(*uuid)); if (diff < 0) { p = p->rb_left; } else if (diff > 0) { p = p->rb_right; } else { |
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afs_get_server(server, afs_server_trace_get_by_uuid); |
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break; } server = NULL; } } while (need_seqretry(&net->fs_lock, seq)); done_seqretry(&net->fs_lock, seq); _leave(" = %p", server); return server; } /* * Install a server record in the namespace tree */ static struct afs_server *afs_install_server(struct afs_net *net, struct afs_server *candidate) { const struct afs_addr_list *alist; 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 */ pp = &net->fs_servers.rb_node; |
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p = NULL; while (*pp) { p = *pp; _debug("- consider %p", p); |
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server = rb_entry(p, struct afs_server, uuid_rb); 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; else |
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goto exists; |
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} |
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server = candidate; rb_link_node(&server->uuid_rb, p, pp); rb_insert_color(&server->uuid_rb, &net->fs_servers); hlist_add_head_rcu(&server->proc_link, &net->fs_proc); write_seqlock(&net->fs_addr_lock); alist = rcu_dereference_protected(server->addresses, lockdep_is_held(&net->fs_addr_lock.lock)); /* Secondly, if the server has any IPv4 and/or IPv6 addresses, install * it in the IPv4 and/or IPv6 reverse-map lists. * * TODO: For speed we want to use something other than a flat list * here; even sorting the list in terms of lowest address would help a * bit, but anything we might want to do gets messy and memory * intensive. */ if (alist->nr_ipv4 > 0) hlist_add_head_rcu(&server->addr4_link, &net->fs_addresses4); if (alist->nr_addrs > alist->nr_ipv4) hlist_add_head_rcu(&server->addr6_link, &net->fs_addresses6); 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); 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, const uuid_t *uuid, 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) 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); server->addr_version = alist->version; server->uuid = *uuid; |
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server->update_at = ktime_get_real_seconds() + afs_server_update_delay; 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); 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: _leave(" = NULL [nomem]"); 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, struct key *key, const uuid_t *uuid) |
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{ |
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struct afs_vl_cursor vc; struct afs_addr_list *alist = NULL; |
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int ret; |
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ret = -ERESTARTSYS; if (afs_begin_vlserver_operation(&vc, cell, key)) { 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); else 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, const uuid_t *uuid) |
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{ |
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struct afs_addr_list *alist; 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); if (server) return server; |
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alist = afs_vl_lookup_addrs(cell, key, uuid); if (IS_ERR(alist)) return ERR_CAST(alist); |
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candidate = afs_alloc_server(cell->net, uuid, alist); if (!candidate) { afs_put_addrlist(alist); return ERR_PTR(-ENOMEM); } |
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server = afs_install_server(cell->net, candidate); if (server != candidate) { afs_put_addrlist(alist); 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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/* * Set the server timer to fire after a given delay, assuming it's not already * set for an earlier time. */ |
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static void afs_set_server_timer(struct afs_net *net, time64_t delay) { |
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if (net->live) { |
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afs_inc_servers_outstanding(net); 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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* Server management timer. We have an increment on fs_outstanding that we * need to pass along to the work item. */ void afs_servers_timer(struct timer_list *timer) { struct afs_net *net = container_of(timer, struct afs_net, fs_timer); _enter(""); if (!queue_work(afs_wq, &net->fs_manager)) afs_dec_servers_outstanding(net); } /* |
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* Get a reference on a server object. */ struct afs_server *afs_get_server(struct afs_server *server, enum afs_server_trace reason) { unsigned int u = atomic_inc_return(&server->usage); trace_afs_server(server, u, reason); return server; } /* |
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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, enum afs_server_trace reason) |
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{ |
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unsigned int usage; |
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if (!server) 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); } static void afs_server_rcu(struct rcu_head *rcu) { struct afs_server *server = container_of(rcu, struct afs_server, rcu); |
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trace_afs_server(server, atomic_read(&server->usage), 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 = { .alist = alist, |
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.index = alist->preferred, |
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.error = 0, }; |
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trace_afs_server(server, atomic_read(&server->usage), afs_server_trace_give_up_cb); |
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if (test_bit(AFS_SERVER_FL_MAY_HAVE_CB, &server->flags)) afs_fs_give_up_all_callbacks(net, server, &ac, NULL); |
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wait_var_event(&server->probe_outstanding, atomic_read(&server->probe_outstanding) == 0); |
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trace_afs_server(server, atomic_read(&server->usage), 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; int usage; while ((server = gc_list)) { gc_list = server->gc_next; write_seqlock(&net->fs_lock); usage = 1; 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) { rb_erase(&server->uuid_rb, &net->fs_servers); 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) { write_seqlock(&net->fs_addr_lock); if (!hlist_unhashed(&server->addr4_link)) hlist_del_rcu(&server->addr4_link); if (!hlist_unhashed(&server->addr6_link)) hlist_del_rcu(&server->addr6_link); write_sequnlock(&net->fs_addr_lock); |
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afs_destroy_server(net, server); |
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} |
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} } /* * Manage the records of servers known to be within a network namespace. This * includes garbage collecting unused servers. * * Note also that we were given an increment on net->servers_outstanding by * whoever queued us that we need to deal with before returning. */ void afs_manage_servers(struct work_struct *work) { struct afs_net *net = container_of(work, struct afs_net, fs_manager); struct afs_server *gc_list = NULL; struct rb_node *cursor; time64_t now = ktime_get_real_seconds(), next_manage = TIME64_MAX; bool purging = !net->live; _enter(""); /* Trawl the server list looking for servers that have expired from * lack of use. */ read_seqlock_excl(&net->fs_lock); 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; } |
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} } |
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read_sequnlock_excl(&net->fs_lock); |
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/* 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); } |
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} |
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afs_gc_servers(net, gc_list); |
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484 |
afs_dec_servers_outstanding(net); |
d2ddc776a
|
485 486 487 488 489 490 491 492 |
_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); |
ec26815ad
|
493 |
} |
1da177e4c
|
494 |
|
1da177e4c
|
495 |
/* |
d2ddc776a
|
496 |
* Purge list of servers. |
1da177e4c
|
497 |
*/ |
d2ddc776a
|
498 |
void afs_purge_servers(struct afs_net *net) |
1da177e4c
|
499 |
{ |
d2ddc776a
|
500 501 502 |
_enter(""); if (del_timer_sync(&net->fs_timer)) |
59fa1c4a9
|
503 |
atomic_dec(&net->servers_outstanding); |
d2ddc776a
|
504 |
afs_queue_server_manager(net); |
59fa1c4a9
|
505 |
|
d2ddc776a
|
506 |
_debug("wait"); |
ab1fbe324
|
507 508 |
wait_var_event(&net->servers_outstanding, !atomic_read(&net->servers_outstanding)); |
d2ddc776a
|
509 510 511 512 |
_leave(""); } /* |
d2ddc776a
|
513 514 515 516 517 518 519 |
* 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(""); |
452181936
|
520 |
trace_afs_server(server, atomic_read(&server->usage), afs_server_trace_update); |
d2ddc776a
|
521 522 523 |
alist = afs_vl_lookup_addrs(fc->vnode->volume->cell, fc->key, &server->uuid); if (IS_ERR(alist)) { |
20b8391ff
|
524 525 526 527 528 529 530 |
if ((PTR_ERR(alist) == -ERESTARTSYS || PTR_ERR(alist) == -EINTR) && !(fc->flags & AFS_FS_CURSOR_INTR) && server->addresses) { _leave(" = t [intr]"); return true; } |
0ab4c9594
|
531 532 |
fc->error = PTR_ERR(alist); _leave(" = f [%d]", fc->error); |
d2ddc776a
|
533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 |
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, |
c2bdc86ec
|
582 583 |
(fc->flags & AFS_FS_CURSOR_INTR) ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE); |
d2ddc776a
|
584 |
if (ret == -ERESTARTSYS) { |
0ab4c9594
|
585 |
fc->error = ret; |
d2ddc776a
|
586 587 588 589 590 591 592 593 594 595 596 |
_leave(" = f [intr]"); return false; } retries++; if (retries == 4) { _leave(" = f [stale]"); ret = -ESTALE; return false; } goto retry; |
ec26815ad
|
597 |
} |