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-rw-r--r--fs/afs/server.c725
1 files changed, 725 insertions, 0 deletions
diff --git a/fs/afs/server.c b/fs/afs/server.c
new file mode 100644
index 000000000..b5237206e
--- /dev/null
+++ b/fs/afs/server.c
@@ -0,0 +1,725 @@
+// 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 struct afs_server *afs_maybe_use_server(struct afs_server *,
+ enum afs_server_trace);
+static void __afs_put_server(struct afs_net *, struct afs_server *);
+
+/*
+ * Find a server by one of its addresses.
+ */
+struct afs_server *afs_find_server(struct afs_net *net,
+ const struct sockaddr_rxrpc *srx)
+{
+ const struct afs_addr_list *alist;
+ struct afs_server *server = NULL;
+ unsigned int i;
+ int seq = 0, diff;
+
+ rcu_read_lock();
+
+ do {
+ if (server)
+ afs_unuse_server_notime(net, server, afs_server_trace_put_find_rsq);
+ server = NULL;
+ read_seqbegin_or_lock(&net->fs_addr_lock, &seq);
+
+ if (srx->transport.family == AF_INET6) {
+ const struct sockaddr_in6 *a = &srx->transport.sin6, *b;
+ 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;
+ diff = ((u16 __force)a->sin6_port -
+ (u16 __force)b->sin6_port);
+ if (diff == 0)
+ diff = memcmp(&a->sin6_addr,
+ &b->sin6_addr,
+ sizeof(struct in6_addr));
+ if (diff == 0)
+ goto found;
+ }
+ }
+ } else {
+ const struct sockaddr_in *a = &srx->transport.sin, *b;
+ hlist_for_each_entry_rcu(server, &net->fs_addresses4, addr4_link) {
+ alist = rcu_dereference(server->addresses);
+ for (i = 0; i < alist->nr_ipv4; i++) {
+ b = &alist->addrs[i].transport.sin;
+ diff = ((u16 __force)a->sin_port -
+ (u16 __force)b->sin_port);
+ if (diff == 0)
+ diff = ((u32 __force)a->sin_addr.s_addr -
+ (u32 __force)b->sin_addr.s_addr);
+ if (diff == 0)
+ goto found;
+ }
+ }
+ }
+
+ server = NULL;
+ continue;
+ found:
+ server = afs_maybe_use_server(server, afs_server_trace_get_by_addr);
+
+ } while (need_seqretry(&net->fs_addr_lock, seq));
+
+ done_seqretry(&net->fs_addr_lock, seq);
+
+ rcu_read_unlock();
+ return server;
+}
+
+/*
+ * Look up a server by its UUID and mark it active.
+ */
+struct afs_server *afs_find_server_by_uuid(struct afs_net *net, const uuid_t *uuid)
+{
+ 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)
+ afs_unuse_server(net, server, afs_server_trace_put_uuid_rsq);
+ 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 {
+ afs_use_server(server, afs_server_trace_get_by_uuid);
+ 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. If there's a clash, we stick
+ * it into a list anchored on whichever afs_server struct is actually in the
+ * tree.
+ */
+static struct afs_server *afs_install_server(struct afs_cell *cell,
+ struct afs_server *candidate)
+{
+ const struct afs_addr_list *alist;
+ struct afs_server *server, *next;
+ struct afs_net *net = cell->net;
+ struct rb_node **pp, *p;
+ int diff;
+
+ _enter("%p", candidate);
+
+ write_seqlock(&net->fs_lock);
+
+ /* Firstly install the server in the UUID lookup tree */
+ pp = &net->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 {
+ if (server->cell == cell)
+ goto exists;
+
+ /* We have the same UUID representing servers in
+ * different cells. Append the new server to the list.
+ */
+ for (;;) {
+ next = rcu_dereference_protected(
+ server->uuid_next,
+ lockdep_is_held(&net->fs_lock.lock));
+ if (!next)
+ break;
+ server = next;
+ }
+ rcu_assign_pointer(server->uuid_next, candidate);
+ candidate->uuid_prev = server;
+ server = candidate;
+ goto added_dup;
+ }
+ }
+
+ 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);
+
+added_dup:
+ 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);
+
+exists:
+ afs_get_server(server, afs_server_trace_get_install);
+ write_sequnlock(&net->fs_lock);
+ return server;
+}
+
+/*
+ * Allocate a new server record and mark it active.
+ */
+static struct afs_server *afs_alloc_server(struct afs_cell *cell,
+ const uuid_t *uuid,
+ struct afs_addr_list *alist)
+{
+ struct afs_server *server;
+ struct afs_net *net = cell->net;
+
+ _enter("");
+
+ server = kzalloc(sizeof(struct afs_server), GFP_KERNEL);
+ if (!server)
+ goto enomem;
+
+ refcount_set(&server->ref, 1);
+ atomic_set(&server->active, 1);
+ server->debug_id = atomic_inc_return(&afs_server_debug_id);
+ RCU_INIT_POINTER(server->addresses, alist);
+ server->addr_version = alist->version;
+ server->uuid = *uuid;
+ rwlock_init(&server->fs_lock);
+ INIT_WORK(&server->initcb_work, afs_server_init_callback_work);
+ init_waitqueue_head(&server->probe_wq);
+ INIT_LIST_HEAD(&server->probe_link);
+ spin_lock_init(&server->probe_lock);
+ server->cell = cell;
+ server->rtt = UINT_MAX;
+
+ afs_inc_servers_outstanding(net);
+ trace_afs_server(server->debug_id, 1, 1, afs_server_trace_alloc);
+ _leave(" = %p", server);
+ return server;
+
+enomem:
+ _leave(" = NULL [nomem]");
+ return NULL;
+}
+
+/*
+ * Look up an address record for a server
+ */
+static struct afs_addr_list *afs_vl_lookup_addrs(struct afs_cell *cell,
+ struct key *key, const uuid_t *uuid)
+{
+ struct afs_vl_cursor vc;
+ struct afs_addr_list *alist = NULL;
+ int ret;
+
+ ret = -ERESTARTSYS;
+ if (afs_begin_vlserver_operation(&vc, cell, key)) {
+ while (afs_select_vlserver(&vc)) {
+ if (test_bit(AFS_VLSERVER_FL_IS_YFS, &vc.server->flags))
+ alist = afs_yfsvl_get_endpoints(&vc, uuid);
+ else
+ alist = afs_vl_get_addrs_u(&vc, uuid);
+ }
+
+ ret = afs_end_vlserver_operation(&vc);
+ }
+
+ return ret < 0 ? ERR_PTR(ret) : alist;
+}
+
+/*
+ * Get or create a fileserver record.
+ */
+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;
+ struct afs_server *server, *candidate;
+
+ _enter("%p,%pU", cell->net, uuid);
+
+ server = afs_find_server_by_uuid(cell->net, uuid);
+ if (server) {
+ if (server->addr_version != addr_version)
+ set_bit(AFS_SERVER_FL_NEEDS_UPDATE, &server->flags);
+ return server;
+ }
+
+ alist = afs_vl_lookup_addrs(cell, key, uuid);
+ if (IS_ERR(alist))
+ return ERR_CAST(alist);
+
+ candidate = afs_alloc_server(cell, uuid, alist);
+ if (!candidate) {
+ afs_put_addrlist(alist);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ server = afs_install_server(cell, candidate);
+ if (server != candidate) {
+ afs_put_addrlist(alist);
+ kfree(candidate);
+ } else {
+ /* Immediately dispatch an asynchronous probe to each interface
+ * on the fileserver. This will make sure the repeat-probing
+ * service is started.
+ */
+ afs_fs_probe_fileserver(cell->net, server, key, true);
+ }
+
+ return server;
+}
+
+/*
+ * Set the server timer to fire after a given delay, assuming it's not already
+ * set for an earlier time.
+ */
+static void afs_set_server_timer(struct afs_net *net, time64_t delay)
+{
+ if (net->live) {
+ afs_inc_servers_outstanding(net);
+ if (timer_reduce(&net->fs_timer, jiffies + delay * HZ))
+ afs_dec_servers_outstanding(net);
+ }
+}
+
+/*
+ * 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);
+}
+
+/*
+ * 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;
+}
+
+/*
+ * Try to get a reference on a server object.
+ */
+static struct afs_server *afs_maybe_use_server(struct afs_server *server,
+ enum afs_server_trace reason)
+{
+ unsigned int a;
+ int r;
+
+ if (!__refcount_inc_not_zero(&server->ref, &r))
+ return NULL;
+
+ a = atomic_inc_return(&server->active);
+ trace_afs_server(server->debug_id, r + 1, a, reason);
+ return server;
+}
+
+/*
+ * Get an active count on a server object.
+ */
+struct afs_server *afs_use_server(struct afs_server *server, enum afs_server_trace reason)
+{
+ unsigned int a;
+ int r;
+
+ __refcount_inc(&server->ref, &r);
+ a = atomic_inc_return(&server->active);
+
+ 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 = server->debug_id;
+ bool zero;
+ int r;
+
+ if (!server)
+ return;
+
+ 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) {
+ unsigned int active = atomic_dec_return(&server->active);
+
+ if (active == 0)
+ afs_set_server_timer(net, afs_server_gc_delay);
+ 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) {
+ server->unuse_time = ktime_get_real_seconds();
+ afs_unuse_server_notime(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_addrlist(rcu_access_pointer(server->addresses));
+ 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_addr_list *alist = rcu_access_pointer(server->addresses);
+ struct afs_addr_cursor ac = {
+ .alist = alist,
+ .index = alist->preferred,
+ .error = 0,
+ };
+
+ afs_fs_give_up_all_callbacks(net, server, &ac, NULL);
+}
+
+/*
+ * destroy a dead server
+ */
+static void afs_destroy_server(struct afs_net *net, struct afs_server *server)
+{
+ if (test_bit(AFS_SERVER_FL_MAY_HAVE_CB, &server->flags))
+ afs_give_up_callbacks(net, server);
+
+ flush_work(&server->initcb_work);
+ afs_put_server(net, server, afs_server_trace_destroy);
+}
+
+/*
+ * Garbage collect any expired servers.
+ */
+static void afs_gc_servers(struct afs_net *net, struct afs_server *gc_list)
+{
+ struct afs_server *server, *next, *prev;
+ int active;
+
+ while ((server = gc_list)) {
+ gc_list = server->gc_next;
+
+ write_seqlock(&net->fs_lock);
+
+ active = atomic_read(&server->active);
+ if (active == 0) {
+ trace_afs_server(server->debug_id, refcount_read(&server->ref),
+ active, afs_server_trace_gc);
+ next = rcu_dereference_protected(
+ server->uuid_next, lockdep_is_held(&net->fs_lock.lock));
+ prev = server->uuid_prev;
+ if (!prev) {
+ /* The one at the front is in the tree */
+ if (!next) {
+ rb_erase(&server->uuid_rb, &net->fs_servers);
+ } else {
+ rb_replace_node_rcu(&server->uuid_rb,
+ &next->uuid_rb,
+ &net->fs_servers);
+ next->uuid_prev = NULL;
+ }
+ } else {
+ /* This server is not at the front */
+ rcu_assign_pointer(prev->uuid_next, next);
+ if (next)
+ next->uuid_prev = prev;
+ }
+
+ list_del(&server->probe_link);
+ hlist_del_rcu(&server->proc_link);
+ 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_lock);
+
+ if (active == 0)
+ afs_destroy_server(net, server);
+ }
+}
+
+/*
+ * 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 active = atomic_read(&server->active);
+
+ _debug("manage %pU %u", &server->uuid, active);
+
+ if (purging) {
+ trace_afs_server(server->debug_id, refcount_read(&server->ref),
+ active, afs_server_trace_purging);
+ if (active != 0)
+ pr_notice("Can't purge s=%08x\n", server->debug_id);
+ }
+
+ if (active == 0) {
+ time64_t expire_at = server->unuse_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))
+ afs_dec_servers_outstanding(net);
+
+ afs_queue_server_manager(net);
+
+ _debug("wait");
+ 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 afs_addr_list *alist, *discard;
+
+ _enter("");
+
+ trace_afs_server(server->debug_id, refcount_read(&server->ref),
+ atomic_read(&server->active),
+ afs_server_trace_update);
+
+ alist = afs_vl_lookup_addrs(op->volume->cell, op->key, &server->uuid);
+ if (IS_ERR(alist)) {
+ if ((PTR_ERR(alist) == -ERESTARTSYS ||
+ PTR_ERR(alist) == -EINTR) &&
+ (op->flags & AFS_OPERATION_UNINTR) &&
+ server->addresses) {
+ _leave(" = t [intr]");
+ return true;
+ }
+ op->error = PTR_ERR(alist);
+ _leave(" = f [%d]", op->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);
+ }
+
+ afs_put_addrlist(discard);
+ _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)
+{
+ 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);
+ 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) {
+ op->error = ret;
+ _leave(" = f [intr]");
+ return false;
+ }
+
+ retries++;
+ if (retries == 4) {
+ _leave(" = f [stale]");
+ ret = -ESTALE;
+ return false;
+ }
+ goto retry;
+}