diff options
Diffstat (limited to 'fs/afs/server.c')
| -rw-r--r-- | fs/afs/server.c | 630 |
1 files changed, 630 insertions, 0 deletions
diff --git a/fs/afs/server.c b/fs/afs/server.c new file mode 100644 index 000000000..189138bd6 --- /dev/null +++ b/fs/afs/server.c @@ -0,0 +1,630 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* AFS server record management + * + * Copyright (C) 2002, 2007 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" + +static unsigned afs_server_gc_delay = 10; /* Server record timeout in seconds */ +static atomic_t afs_server_debug_id; + +static void __afs_put_server(struct afs_net *, struct afs_server *); +static void afs_server_timer(struct timer_list *timer); +static void afs_server_destroyer(struct work_struct *work); + +/* + * Find a server by one of its addresses. + */ +struct afs_server *afs_find_server(const struct rxrpc_peer *peer) +{ + struct afs_server *server = (struct afs_server *)rxrpc_kernel_get_peer_data(peer); + + if (!server) + return NULL; + return afs_use_server(server, false, afs_server_trace_use_cm_call); +} + +/* + * Look up a server by its UUID and mark it active. The caller must hold + * cell->fs_lock. + */ +static struct afs_server *afs_find_server_by_uuid(struct afs_cell *cell, const uuid_t *uuid) +{ + struct afs_server *server; + struct rb_node *p; + int diff; + + _enter("%pU", uuid); + + p = cell->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 { + if (test_bit(AFS_SERVER_FL_UNCREATED, &server->flags)) + return NULL; /* Need a write lock */ + afs_use_server(server, true, afs_server_trace_use_by_uuid); + return server; + } + } + + return NULL; +} + +/* + * Install a server record in the cell tree. The caller must hold an exclusive + * lock on cell->fs_lock. + */ +static struct afs_server *afs_install_server(struct afs_cell *cell, + struct afs_server **candidate) +{ + struct afs_server *server; + struct afs_net *net = cell->net; + struct rb_node **pp, *p; + int diff; + + _enter("%p", candidate); + + /* Firstly install the server in the UUID lookup tree */ + pp = &cell->fs_servers.rb_node; + p = NULL; + while (*pp) { + p = *pp; + _debug("- consider %p", p); + server = rb_entry(p, struct afs_server, uuid_rb); + diff = memcmp(&(*candidate)->uuid, &server->uuid, sizeof(uuid_t)); + if (diff < 0) + pp = &(*pp)->rb_left; + else if (diff > 0) + pp = &(*pp)->rb_right; + else + goto exists; + } + + server = *candidate; + *candidate = NULL; + rb_link_node(&server->uuid_rb, p, pp); + rb_insert_color(&server->uuid_rb, &cell->fs_servers); + write_seqlock(&net->fs_lock); + hlist_add_head_rcu(&server->proc_link, &net->fs_proc); + write_sequnlock(&net->fs_lock); + + afs_get_cell(cell, afs_cell_trace_get_server); + +exists: + afs_use_server(server, true, afs_server_trace_use_install); + return server; +} + +/* + * Allocate a new server record and mark it as active but uncreated. + */ +static struct afs_server *afs_alloc_server(struct afs_cell *cell, const uuid_t *uuid) +{ + struct afs_server *server; + struct afs_net *net = cell->net; + + _enter(""); + + server = kzalloc_obj(struct afs_server); + if (!server) + return NULL; + + refcount_set(&server->ref, 1); + atomic_set(&server->active, 0); + __set_bit(AFS_SERVER_FL_UNCREATED, &server->flags); + server->debug_id = atomic_inc_return(&afs_server_debug_id); + server->uuid = *uuid; + rwlock_init(&server->fs_lock); + INIT_WORK(&server->destroyer, &afs_server_destroyer); + timer_setup(&server->timer, afs_server_timer, 0); + INIT_LIST_HEAD(&server->volumes); + init_waitqueue_head(&server->probe_wq); + mutex_init(&server->cm_token_lock); + INIT_LIST_HEAD(&server->probe_link); + INIT_HLIST_NODE(&server->proc_link); + spin_lock_init(&server->probe_lock); + server->cell = cell; + server->rtt = UINT_MAX; + server->service_id = FS_SERVICE; + server->probe_counter = 1; + server->probed_at = jiffies - LONG_MAX / 2; + + afs_inc_servers_outstanding(net); + _leave(" = %p", server); + return server; +} + +/* + * Look up an address record for a server + */ +static struct afs_addr_list *afs_vl_lookup_addrs(struct afs_server *server, + struct key *key) +{ + struct afs_vl_cursor vc; + struct afs_addr_list *alist = NULL; + int ret; + + ret = -ERESTARTSYS; + if (afs_begin_vlserver_operation(&vc, server->cell, key)) { + while (afs_select_vlserver(&vc)) { + if (test_bit(AFS_VLSERVER_FL_IS_YFS, &vc.server->flags)) + alist = afs_yfsvl_get_endpoints(&vc, &server->uuid); + else + alist = afs_vl_get_addrs_u(&vc, &server->uuid); + } + + ret = afs_end_vlserver_operation(&vc); + } + + return ret < 0 ? ERR_PTR(ret) : alist; +} + +/* + * Get or create a fileserver record and return it with an active-use count on + * it. + */ +struct afs_server *afs_lookup_server(struct afs_cell *cell, struct key *key, + const uuid_t *uuid, u32 addr_version) +{ + struct afs_addr_list *alist = NULL; + struct afs_server *server, *candidate = NULL; + bool creating = false; + int ret; + + _enter("%p,%pU", cell->net, uuid); + + down_read(&cell->fs_lock); + server = afs_find_server_by_uuid(cell, uuid); + /* Won't see servers marked uncreated. */ + up_read(&cell->fs_lock); + + if (server) { + timer_delete_sync(&server->timer); + if (test_bit(AFS_SERVER_FL_CREATING, &server->flags)) + goto wait_for_creation; + if (server->addr_version != addr_version) + set_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags); + return server; + } + + candidate = afs_alloc_server(cell, uuid); + if (!candidate) { + afs_put_addrlist(alist, afs_alist_trace_put_server_oom); + return ERR_PTR(-ENOMEM); + } + + down_write(&cell->fs_lock); + server = afs_install_server(cell, &candidate); + if (test_bit(AFS_SERVER_FL_CREATING, &server->flags)) { + /* We need to wait for creation to complete. */ + up_write(&cell->fs_lock); + goto wait_for_creation; + } + if (test_bit(AFS_SERVER_FL_UNCREATED, &server->flags)) { + set_bit(AFS_SERVER_FL_CREATING, &server->flags); + clear_bit(AFS_SERVER_FL_UNCREATED, &server->flags); + creating = true; + } + up_write(&cell->fs_lock); + timer_delete_sync(&server->timer); + + /* If we get to create the server, we look up the addresses and then + * immediately dispatch an asynchronous probe to each interface on the + * fileserver. This will make sure the repeat-probing service is + * started. + */ + if (creating) { + alist = afs_vl_lookup_addrs(server, key); + if (IS_ERR(alist)) { + ret = PTR_ERR(alist); + goto create_failed; + } + + ret = afs_fs_probe_fileserver(cell->net, server, alist, key); + if (ret) + goto create_failed; + + clear_and_wake_up_bit(AFS_SERVER_FL_CREATING, &server->flags); + } + +out: + afs_put_addrlist(alist, afs_alist_trace_put_server_create); + if (candidate) { + kfree(candidate); + afs_dec_servers_outstanding(cell->net); + } + return server ?: ERR_PTR(ret); + +wait_for_creation: + afs_see_server(server, afs_server_trace_wait_create); + wait_on_bit(&server->flags, AFS_SERVER_FL_CREATING, TASK_UNINTERRUPTIBLE); + if (test_bit_acquire(AFS_SERVER_FL_UNCREATED, &server->flags)) { + /* Barrier: read flag before error */ + ret = READ_ONCE(server->create_error); + afs_put_server(cell->net, server, afs_server_trace_unuse_create_fail); + server = NULL; + goto out; + } + + ret = 0; + goto out; + +create_failed: + down_write(&cell->fs_lock); + + WRITE_ONCE(server->create_error, ret); + smp_wmb(); /* Barrier: set error before flag. */ + set_bit(AFS_SERVER_FL_UNCREATED, &server->flags); + + clear_and_wake_up_bit(AFS_SERVER_FL_CREATING, &server->flags); + + if (test_bit(AFS_SERVER_FL_UNCREATED, &server->flags)) { + clear_bit(AFS_SERVER_FL_UNCREATED, &server->flags); + creating = true; + } + afs_unuse_server(cell->net, server, afs_server_trace_unuse_create_fail); + server = NULL; + + up_write(&cell->fs_lock); + goto out; +} + +/* + * Set/reduce a server's timer. + */ +static void afs_set_server_timer(struct afs_server *server, unsigned int delay_secs) +{ + mod_timer(&server->timer, jiffies + delay_secs * HZ); +} + +/* + * Get a reference on a server object. + */ +struct afs_server *afs_get_server(struct afs_server *server, + enum afs_server_trace reason) +{ + unsigned int a; + int r; + + __refcount_inc(&server->ref, &r); + a = atomic_read(&server->active); + trace_afs_server(server->debug_id, r + 1, a, reason); + return server; +} + +/* + * Get an active count on a server object and maybe remove from the inactive + * list. + */ +struct afs_server *afs_use_server(struct afs_server *server, bool activate, + enum afs_server_trace reason) +{ + unsigned int a; + int r; + + __refcount_inc(&server->ref, &r); + a = atomic_inc_return(&server->active); + if (a == 1 && activate && + !test_bit(AFS_SERVER_FL_EXPIRED, &server->flags)) + timer_delete(&server->timer); + + trace_afs_server(server->debug_id, r + 1, a, reason); + return server; +} + +/* + * Release a reference on a server record. + */ +void afs_put_server(struct afs_net *net, struct afs_server *server, + enum afs_server_trace reason) +{ + unsigned int a, debug_id; + bool zero; + int r; + + if (!server) + return; + + debug_id = server->debug_id; + a = atomic_read(&server->active); + zero = __refcount_dec_and_test(&server->ref, &r); + trace_afs_server(debug_id, r - 1, a, reason); + if (unlikely(zero)) + __afs_put_server(net, server); +} + +/* + * Drop an active count on a server object without updating the last-unused + * time. + */ +void afs_unuse_server_notime(struct afs_net *net, struct afs_server *server, + enum afs_server_trace reason) +{ + if (!server) + return; + + if (atomic_dec_and_test(&server->active)) { + if (test_bit(AFS_SERVER_FL_EXPIRED, &server->flags) || + READ_ONCE(server->cell->state) >= AFS_CELL_REMOVING) + schedule_work(&server->destroyer); + } + + afs_put_server(net, server, reason); +} + +/* + * Drop an active count on a server object. + */ +void afs_unuse_server(struct afs_net *net, struct afs_server *server, + enum afs_server_trace reason) +{ + if (!server) + return; + + if (atomic_dec_and_test(&server->active)) { + if (!test_bit(AFS_SERVER_FL_EXPIRED, &server->flags) && + READ_ONCE(server->cell->state) < AFS_CELL_REMOVING) { + time64_t unuse_time = ktime_get_real_seconds(); + + server->unuse_time = unuse_time; + afs_set_server_timer(server, afs_server_gc_delay); + } else { + schedule_work(&server->destroyer); + } + } + + afs_put_server(net, server, reason); +} + +static void afs_server_rcu(struct rcu_head *rcu) +{ + struct afs_server *server = container_of(rcu, struct afs_server, rcu); + + trace_afs_server(server->debug_id, refcount_read(&server->ref), + atomic_read(&server->active), afs_server_trace_free); + afs_put_endpoint_state(rcu_access_pointer(server->endpoint_state), + afs_estate_trace_put_server); + afs_put_cell(server->cell, afs_cell_trace_put_server); + kfree(server->cm_rxgk_appdata.data); + kfree(server); +} + +static void __afs_put_server(struct afs_net *net, struct afs_server *server) +{ + call_rcu(&server->rcu, afs_server_rcu); + afs_dec_servers_outstanding(net); +} + +static void afs_give_up_callbacks(struct afs_net *net, struct afs_server *server) +{ + struct afs_endpoint_state *estate = rcu_access_pointer(server->endpoint_state); + struct afs_addr_list *alist = estate->addresses; + + afs_fs_give_up_all_callbacks(net, server, &alist->addrs[alist->preferred], NULL); +} + +/* + * Check to see if the server record has expired. + */ +static bool afs_has_server_expired(const struct afs_server *server) +{ + time64_t expires_at; + + if (atomic_read(&server->active)) + return false; + + if (server->cell->net->live || + server->cell->state >= AFS_CELL_REMOVING) { + trace_afs_server(server->debug_id, refcount_read(&server->ref), + 0, afs_server_trace_purging); + return true; + } + + expires_at = server->unuse_time; + if (!test_bit(AFS_SERVER_FL_VL_FAIL, &server->flags) && + !test_bit(AFS_SERVER_FL_NOT_FOUND, &server->flags)) + expires_at += afs_server_gc_delay; + + return ktime_get_real_seconds() > expires_at; +} + +/* + * Remove a server record from it's parent cell's database. + */ +static bool afs_remove_server_from_cell(struct afs_server *server) +{ + struct afs_cell *cell = server->cell; + + down_write(&cell->fs_lock); + + if (!afs_has_server_expired(server)) { + up_write(&cell->fs_lock); + return false; + } + + set_bit(AFS_SERVER_FL_EXPIRED, &server->flags); + _debug("expire %pU %u", &server->uuid, atomic_read(&server->active)); + afs_see_server(server, afs_server_trace_see_expired); + rb_erase(&server->uuid_rb, &cell->fs_servers); + up_write(&cell->fs_lock); + return true; +} + +static void afs_server_destroyer(struct work_struct *work) +{ + struct afs_endpoint_state *estate; + struct afs_server *server = container_of(work, struct afs_server, destroyer); + struct afs_net *net = server->cell->net; + + afs_see_server(server, afs_server_trace_see_destroyer); + + if (test_bit(AFS_SERVER_FL_EXPIRED, &server->flags)) + return; + + if (!afs_remove_server_from_cell(server)) + return; + + timer_shutdown_sync(&server->timer); + cancel_work(&server->destroyer); + + if (test_bit(AFS_SERVER_FL_MAY_HAVE_CB, &server->flags)) + afs_give_up_callbacks(net, server); + + /* Unbind the rxrpc_peer records from the server. */ + estate = rcu_access_pointer(server->endpoint_state); + if (estate) + afs_set_peer_appdata(server, estate->addresses, NULL); + + write_seqlock(&net->fs_lock); + list_del_init(&server->probe_link); + if (!hlist_unhashed(&server->proc_link)) + hlist_del_rcu(&server->proc_link); + write_sequnlock(&net->fs_lock); + + afs_put_server(net, server, afs_server_trace_destroy); +} + +static void afs_server_timer(struct timer_list *timer) +{ + struct afs_server *server = container_of(timer, struct afs_server, timer); + + afs_see_server(server, afs_server_trace_see_timer); + if (!test_bit(AFS_SERVER_FL_EXPIRED, &server->flags)) + schedule_work(&server->destroyer); +} + +/* + * Wake up all the servers in a cell so that they can purge themselves. + */ +void afs_purge_servers(struct afs_cell *cell) +{ + struct afs_server *server; + struct rb_node *rb; + + down_read(&cell->fs_lock); + for (rb = rb_first(&cell->fs_servers); rb; rb = rb_next(rb)) { + server = rb_entry(rb, struct afs_server, uuid_rb); + afs_see_server(server, afs_server_trace_see_purge); + schedule_work(&server->destroyer); + } + up_read(&cell->fs_lock); +} + +/* + * Wait for outstanding servers. + */ +void afs_wait_for_servers(struct afs_net *net) +{ + _enter(""); + + atomic_dec(&net->servers_outstanding); + 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_operation *op, + struct afs_server *server, + struct key *key) +{ + struct afs_endpoint_state *estate; + struct afs_addr_list *alist; + bool has_addrs; + + _enter(""); + + trace_afs_server(server->debug_id, refcount_read(&server->ref), + atomic_read(&server->active), + afs_server_trace_update); + + alist = afs_vl_lookup_addrs(server, op->key); + if (IS_ERR(alist)) { + rcu_read_lock(); + estate = rcu_dereference(server->endpoint_state); + has_addrs = estate->addresses; + rcu_read_unlock(); + + if ((PTR_ERR(alist) == -ERESTARTSYS || + PTR_ERR(alist) == -EINTR) && + (op->flags & AFS_OPERATION_UNINTR) && + has_addrs) { + _leave(" = t [intr]"); + return true; + } + afs_op_set_error(op, PTR_ERR(alist)); + _leave(" = f [%d]", afs_op_error(op)); + return false; + } + + if (server->addr_version != alist->version) + afs_fs_probe_fileserver(op->net, server, alist, key); + + afs_put_addrlist(alist, afs_alist_trace_put_server_update); + _leave(" = t"); + return true; +} + +/* + * See if a server's address list needs updating. + */ +bool afs_check_server_record(struct afs_operation *op, struct afs_server *server, + struct key *key) +{ + bool success; + int ret, retries = 0; + + _enter(""); + + ASSERT(server); + +retry: + if (test_bit(AFS_SERVER_FL_UPDATING, &server->flags)) + goto wait; + if (test_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags)) + goto update; + _leave(" = t [good]"); + return true; + +update: + if (!test_and_set_bit_lock(AFS_SERVER_FL_UPDATING, &server->flags)) { + clear_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags); + success = afs_update_server_record(op, server, key); + clear_bit_unlock(AFS_SERVER_FL_UPDATING, &server->flags); + wake_up_bit(&server->flags, AFS_SERVER_FL_UPDATING); + _leave(" = %d", success); + return success; + } + +wait: + ret = wait_on_bit(&server->flags, AFS_SERVER_FL_UPDATING, + (op->flags & AFS_OPERATION_UNINTR) ? + TASK_UNINTERRUPTIBLE : TASK_INTERRUPTIBLE); + if (ret == -ERESTARTSYS) { + afs_op_set_error(op, ret); + _leave(" = f [intr]"); + return false; + } + + retries++; + if (retries == 4) { + _leave(" = f [stale]"); + ret = -ESTALE; + return false; + } + goto retry; +} |