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![David Howells](/assets/img/avatar_default.png)
Use refcount_t rather than atomic_t in afs to make use of the count checking facilities provided. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Marc Dionne <marc.dionne@auristor.com> cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/165911277768.3745403.423349776836296452.stgit@warthog.procyon.org.uk/ # v1
952 lines
23 KiB
C
952 lines
23 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* AFS cell and server record management
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*
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* Copyright (C) 2002, 2017 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/slab.h>
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#include <linux/key.h>
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#include <linux/ctype.h>
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#include <linux/dns_resolver.h>
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#include <linux/sched.h>
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#include <linux/inet.h>
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#include <linux/namei.h>
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#include <keys/rxrpc-type.h>
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#include "internal.h"
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static unsigned __read_mostly afs_cell_gc_delay = 10;
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static unsigned __read_mostly afs_cell_min_ttl = 10 * 60;
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static unsigned __read_mostly afs_cell_max_ttl = 24 * 60 * 60;
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static atomic_t cell_debug_id;
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static void afs_queue_cell_manager(struct afs_net *);
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static void afs_manage_cell_work(struct work_struct *);
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static void afs_dec_cells_outstanding(struct afs_net *net)
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{
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if (atomic_dec_and_test(&net->cells_outstanding))
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wake_up_var(&net->cells_outstanding);
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}
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/*
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* Set the cell 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_cell_timer(struct afs_net *net, time64_t delay)
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{
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if (net->live) {
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atomic_inc(&net->cells_outstanding);
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if (timer_reduce(&net->cells_timer, jiffies + delay * HZ))
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afs_dec_cells_outstanding(net);
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} else {
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afs_queue_cell_manager(net);
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}
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}
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/*
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* Look up and get an activation reference on a cell record. The caller must
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* hold net->cells_lock at least read-locked.
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*/
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static struct afs_cell *afs_find_cell_locked(struct afs_net *net,
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const char *name, unsigned int namesz,
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enum afs_cell_trace reason)
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{
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struct afs_cell *cell = NULL;
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struct rb_node *p;
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int n;
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_enter("%*.*s", namesz, namesz, name);
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if (name && namesz == 0)
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return ERR_PTR(-EINVAL);
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if (namesz > AFS_MAXCELLNAME)
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return ERR_PTR(-ENAMETOOLONG);
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if (!name) {
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cell = net->ws_cell;
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if (!cell)
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return ERR_PTR(-EDESTADDRREQ);
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goto found;
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}
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p = net->cells.rb_node;
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while (p) {
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cell = rb_entry(p, struct afs_cell, net_node);
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n = strncasecmp(cell->name, name,
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min_t(size_t, cell->name_len, namesz));
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if (n == 0)
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n = cell->name_len - namesz;
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if (n < 0)
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p = p->rb_left;
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else if (n > 0)
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p = p->rb_right;
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else
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goto found;
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}
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return ERR_PTR(-ENOENT);
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found:
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return afs_use_cell(cell, reason);
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}
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/*
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* Look up and get an activation reference on a cell record.
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*/
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struct afs_cell *afs_find_cell(struct afs_net *net,
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const char *name, unsigned int namesz,
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enum afs_cell_trace reason)
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{
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struct afs_cell *cell;
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down_read(&net->cells_lock);
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cell = afs_find_cell_locked(net, name, namesz, reason);
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up_read(&net->cells_lock);
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return cell;
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}
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/*
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* Set up a cell record and fill in its name, VL server address list and
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* allocate an anonymous key
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*/
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static struct afs_cell *afs_alloc_cell(struct afs_net *net,
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const char *name, unsigned int namelen,
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const char *addresses)
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{
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struct afs_vlserver_list *vllist;
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struct afs_cell *cell;
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int i, ret;
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ASSERT(name);
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if (namelen == 0)
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return ERR_PTR(-EINVAL);
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if (namelen > AFS_MAXCELLNAME) {
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_leave(" = -ENAMETOOLONG");
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return ERR_PTR(-ENAMETOOLONG);
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}
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/* Prohibit cell names that contain unprintable chars, '/' and '@' or
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* that begin with a dot. This also precludes "@cell".
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*/
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if (name[0] == '.')
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return ERR_PTR(-EINVAL);
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for (i = 0; i < namelen; i++) {
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char ch = name[i];
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if (!isprint(ch) || ch == '/' || ch == '@')
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return ERR_PTR(-EINVAL);
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}
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_enter("%*.*s,%s", namelen, namelen, name, addresses);
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cell = kzalloc(sizeof(struct afs_cell), GFP_KERNEL);
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if (!cell) {
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_leave(" = -ENOMEM");
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return ERR_PTR(-ENOMEM);
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}
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cell->name = kmalloc(namelen + 1, GFP_KERNEL);
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if (!cell->name) {
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kfree(cell);
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return ERR_PTR(-ENOMEM);
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}
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cell->net = net;
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cell->name_len = namelen;
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for (i = 0; i < namelen; i++)
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cell->name[i] = tolower(name[i]);
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cell->name[i] = 0;
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refcount_set(&cell->ref, 1);
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atomic_set(&cell->active, 0);
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INIT_WORK(&cell->manager, afs_manage_cell_work);
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cell->volumes = RB_ROOT;
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INIT_HLIST_HEAD(&cell->proc_volumes);
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seqlock_init(&cell->volume_lock);
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cell->fs_servers = RB_ROOT;
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seqlock_init(&cell->fs_lock);
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INIT_LIST_HEAD(&cell->fs_open_mmaps);
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init_rwsem(&cell->fs_open_mmaps_lock);
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rwlock_init(&cell->vl_servers_lock);
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cell->flags = (1 << AFS_CELL_FL_CHECK_ALIAS);
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/* Provide a VL server list, filling it in if we were given a list of
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* addresses to use.
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*/
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if (addresses) {
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vllist = afs_parse_text_addrs(net,
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addresses, strlen(addresses), ':',
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VL_SERVICE, AFS_VL_PORT);
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if (IS_ERR(vllist)) {
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ret = PTR_ERR(vllist);
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goto parse_failed;
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}
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vllist->source = DNS_RECORD_FROM_CONFIG;
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vllist->status = DNS_LOOKUP_NOT_DONE;
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cell->dns_expiry = TIME64_MAX;
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} else {
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ret = -ENOMEM;
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vllist = afs_alloc_vlserver_list(0);
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if (!vllist)
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goto error;
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vllist->source = DNS_RECORD_UNAVAILABLE;
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vllist->status = DNS_LOOKUP_NOT_DONE;
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cell->dns_expiry = ktime_get_real_seconds();
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}
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rcu_assign_pointer(cell->vl_servers, vllist);
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cell->dns_source = vllist->source;
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cell->dns_status = vllist->status;
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smp_store_release(&cell->dns_lookup_count, 1); /* vs source/status */
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atomic_inc(&net->cells_outstanding);
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cell->debug_id = atomic_inc_return(&cell_debug_id);
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trace_afs_cell(cell->debug_id, 1, 0, afs_cell_trace_alloc);
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_leave(" = %p", cell);
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return cell;
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parse_failed:
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if (ret == -EINVAL)
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printk(KERN_ERR "kAFS: bad VL server IP address\n");
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error:
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kfree(cell->name);
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kfree(cell);
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_leave(" = %d", ret);
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return ERR_PTR(ret);
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}
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/*
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* afs_lookup_cell - Look up or create a cell record.
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* @net: The network namespace
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* @name: The name of the cell.
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* @namesz: The strlen of the cell name.
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* @vllist: A colon/comma separated list of numeric IP addresses or NULL.
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* @excl: T if an error should be given if the cell name already exists.
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*
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* Look up a cell record by name and query the DNS for VL server addresses if
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* needed. Note that that actual DNS query is punted off to the manager thread
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* so that this function can return immediately if interrupted whilst allowing
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* cell records to be shared even if not yet fully constructed.
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*/
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struct afs_cell *afs_lookup_cell(struct afs_net *net,
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const char *name, unsigned int namesz,
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const char *vllist, bool excl)
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{
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struct afs_cell *cell, *candidate, *cursor;
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struct rb_node *parent, **pp;
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enum afs_cell_state state;
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int ret, n;
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_enter("%s,%s", name, vllist);
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if (!excl) {
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cell = afs_find_cell(net, name, namesz, afs_cell_trace_use_lookup);
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if (!IS_ERR(cell))
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goto wait_for_cell;
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}
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/* Assume we're probably going to create a cell and preallocate and
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* mostly set up a candidate record. We can then use this to stash the
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* name, the net namespace and VL server addresses.
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*
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* We also want to do this before we hold any locks as it may involve
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* upcalling to userspace to make DNS queries.
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*/
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candidate = afs_alloc_cell(net, name, namesz, vllist);
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if (IS_ERR(candidate)) {
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_leave(" = %ld", PTR_ERR(candidate));
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return candidate;
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}
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/* Find the insertion point and check to see if someone else added a
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* cell whilst we were allocating.
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*/
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down_write(&net->cells_lock);
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pp = &net->cells.rb_node;
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parent = NULL;
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while (*pp) {
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parent = *pp;
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cursor = rb_entry(parent, struct afs_cell, net_node);
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n = strncasecmp(cursor->name, name,
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min_t(size_t, cursor->name_len, namesz));
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if (n == 0)
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n = cursor->name_len - namesz;
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if (n < 0)
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pp = &(*pp)->rb_left;
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else if (n > 0)
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pp = &(*pp)->rb_right;
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else
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goto cell_already_exists;
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}
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cell = candidate;
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candidate = NULL;
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atomic_set(&cell->active, 2);
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trace_afs_cell(cell->debug_id, refcount_read(&cell->ref), 2, afs_cell_trace_insert);
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rb_link_node_rcu(&cell->net_node, parent, pp);
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rb_insert_color(&cell->net_node, &net->cells);
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up_write(&net->cells_lock);
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afs_queue_cell(cell, afs_cell_trace_get_queue_new);
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wait_for_cell:
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trace_afs_cell(cell->debug_id, refcount_read(&cell->ref), atomic_read(&cell->active),
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afs_cell_trace_wait);
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_debug("wait_for_cell");
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wait_var_event(&cell->state,
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({
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state = smp_load_acquire(&cell->state); /* vs error */
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state == AFS_CELL_ACTIVE || state == AFS_CELL_REMOVED;
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}));
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/* Check the state obtained from the wait check. */
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if (state == AFS_CELL_REMOVED) {
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ret = cell->error;
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goto error;
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}
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_leave(" = %p [cell]", cell);
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return cell;
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cell_already_exists:
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_debug("cell exists");
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cell = cursor;
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if (excl) {
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ret = -EEXIST;
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} else {
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afs_use_cell(cursor, afs_cell_trace_use_lookup);
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ret = 0;
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}
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up_write(&net->cells_lock);
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if (candidate)
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afs_put_cell(candidate, afs_cell_trace_put_candidate);
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if (ret == 0)
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goto wait_for_cell;
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goto error_noput;
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error:
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afs_unuse_cell(net, cell, afs_cell_trace_unuse_lookup);
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error_noput:
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_leave(" = %d [error]", ret);
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return ERR_PTR(ret);
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}
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/*
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* set the root cell information
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* - can be called with a module parameter string
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* - can be called from a write to /proc/fs/afs/rootcell
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*/
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int afs_cell_init(struct afs_net *net, const char *rootcell)
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{
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struct afs_cell *old_root, *new_root;
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const char *cp, *vllist;
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size_t len;
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_enter("");
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if (!rootcell) {
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/* module is loaded with no parameters, or built statically.
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* - in the future we might initialize cell DB here.
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*/
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_leave(" = 0 [no root]");
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return 0;
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}
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cp = strchr(rootcell, ':');
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if (!cp) {
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_debug("kAFS: no VL server IP addresses specified");
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vllist = NULL;
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len = strlen(rootcell);
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} else {
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vllist = cp + 1;
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len = cp - rootcell;
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}
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/* allocate a cell record for the root cell */
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new_root = afs_lookup_cell(net, rootcell, len, vllist, false);
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if (IS_ERR(new_root)) {
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_leave(" = %ld", PTR_ERR(new_root));
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return PTR_ERR(new_root);
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}
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if (!test_and_set_bit(AFS_CELL_FL_NO_GC, &new_root->flags))
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afs_use_cell(new_root, afs_cell_trace_use_pin);
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/* install the new cell */
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down_write(&net->cells_lock);
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afs_see_cell(new_root, afs_cell_trace_see_ws);
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old_root = net->ws_cell;
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net->ws_cell = new_root;
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up_write(&net->cells_lock);
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afs_unuse_cell(net, old_root, afs_cell_trace_unuse_ws);
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_leave(" = 0");
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return 0;
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}
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/*
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* Update a cell's VL server address list from the DNS.
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*/
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static int afs_update_cell(struct afs_cell *cell)
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{
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struct afs_vlserver_list *vllist, *old = NULL, *p;
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unsigned int min_ttl = READ_ONCE(afs_cell_min_ttl);
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unsigned int max_ttl = READ_ONCE(afs_cell_max_ttl);
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time64_t now, expiry = 0;
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int ret = 0;
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_enter("%s", cell->name);
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vllist = afs_dns_query(cell, &expiry);
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if (IS_ERR(vllist)) {
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ret = PTR_ERR(vllist);
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_debug("%s: fail %d", cell->name, ret);
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if (ret == -ENOMEM)
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goto out_wake;
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ret = -ENOMEM;
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vllist = afs_alloc_vlserver_list(0);
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if (!vllist)
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goto out_wake;
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switch (ret) {
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case -ENODATA:
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case -EDESTADDRREQ:
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vllist->status = DNS_LOOKUP_GOT_NOT_FOUND;
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break;
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case -EAGAIN:
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case -ECONNREFUSED:
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vllist->status = DNS_LOOKUP_GOT_TEMP_FAILURE;
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break;
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default:
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vllist->status = DNS_LOOKUP_GOT_LOCAL_FAILURE;
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break;
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}
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}
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_debug("%s: got list %d %d", cell->name, vllist->source, vllist->status);
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cell->dns_status = vllist->status;
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now = ktime_get_real_seconds();
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if (min_ttl > max_ttl)
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max_ttl = min_ttl;
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if (expiry < now + min_ttl)
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expiry = now + min_ttl;
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else if (expiry > now + max_ttl)
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expiry = now + max_ttl;
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_debug("%s: status %d", cell->name, vllist->status);
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if (vllist->source == DNS_RECORD_UNAVAILABLE) {
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switch (vllist->status) {
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case DNS_LOOKUP_GOT_NOT_FOUND:
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/* The DNS said that the cell does not exist or there
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* weren't any addresses to be had.
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*/
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cell->dns_expiry = expiry;
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break;
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case DNS_LOOKUP_BAD:
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case DNS_LOOKUP_GOT_LOCAL_FAILURE:
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case DNS_LOOKUP_GOT_TEMP_FAILURE:
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case DNS_LOOKUP_GOT_NS_FAILURE:
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default:
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cell->dns_expiry = now + 10;
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break;
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}
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} else {
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cell->dns_expiry = expiry;
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}
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/* Replace the VL server list if the new record has servers or the old
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* record doesn't.
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*/
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write_lock(&cell->vl_servers_lock);
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p = rcu_dereference_protected(cell->vl_servers, true);
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if (vllist->nr_servers > 0 || p->nr_servers == 0) {
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rcu_assign_pointer(cell->vl_servers, vllist);
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cell->dns_source = vllist->source;
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old = p;
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}
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write_unlock(&cell->vl_servers_lock);
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afs_put_vlserverlist(cell->net, old);
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out_wake:
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smp_store_release(&cell->dns_lookup_count,
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cell->dns_lookup_count + 1); /* vs source/status */
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wake_up_var(&cell->dns_lookup_count);
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* Destroy a cell record
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*/
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static void afs_cell_destroy(struct rcu_head *rcu)
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{
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struct afs_cell *cell = container_of(rcu, struct afs_cell, rcu);
|
|
struct afs_net *net = cell->net;
|
|
int r;
|
|
|
|
_enter("%p{%s}", cell, cell->name);
|
|
|
|
r = refcount_read(&cell->ref);
|
|
ASSERTCMP(r, ==, 0);
|
|
trace_afs_cell(cell->debug_id, r, atomic_read(&cell->active), afs_cell_trace_free);
|
|
|
|
afs_put_vlserverlist(net, rcu_access_pointer(cell->vl_servers));
|
|
afs_unuse_cell(net, cell->alias_of, afs_cell_trace_unuse_alias);
|
|
key_put(cell->anonymous_key);
|
|
kfree(cell->name);
|
|
kfree(cell);
|
|
|
|
afs_dec_cells_outstanding(net);
|
|
_leave(" [destroyed]");
|
|
}
|
|
|
|
/*
|
|
* Queue the cell manager.
|
|
*/
|
|
static void afs_queue_cell_manager(struct afs_net *net)
|
|
{
|
|
int outstanding = atomic_inc_return(&net->cells_outstanding);
|
|
|
|
_enter("%d", outstanding);
|
|
|
|
if (!queue_work(afs_wq, &net->cells_manager))
|
|
afs_dec_cells_outstanding(net);
|
|
}
|
|
|
|
/*
|
|
* Cell management timer. We have an increment on cells_outstanding that we
|
|
* need to pass along to the work item.
|
|
*/
|
|
void afs_cells_timer(struct timer_list *timer)
|
|
{
|
|
struct afs_net *net = container_of(timer, struct afs_net, cells_timer);
|
|
|
|
_enter("");
|
|
if (!queue_work(afs_wq, &net->cells_manager))
|
|
afs_dec_cells_outstanding(net);
|
|
}
|
|
|
|
/*
|
|
* Get a reference on a cell record.
|
|
*/
|
|
struct afs_cell *afs_get_cell(struct afs_cell *cell, enum afs_cell_trace reason)
|
|
{
|
|
int r;
|
|
|
|
__refcount_inc(&cell->ref, &r);
|
|
trace_afs_cell(cell->debug_id, r + 1, atomic_read(&cell->active), reason);
|
|
return cell;
|
|
}
|
|
|
|
/*
|
|
* Drop a reference on a cell record.
|
|
*/
|
|
void afs_put_cell(struct afs_cell *cell, enum afs_cell_trace reason)
|
|
{
|
|
if (cell) {
|
|
unsigned int debug_id = cell->debug_id;
|
|
unsigned int a;
|
|
bool zero;
|
|
int r;
|
|
|
|
a = atomic_read(&cell->active);
|
|
zero = __refcount_dec_and_test(&cell->ref, &r);
|
|
trace_afs_cell(debug_id, r - 1, a, reason);
|
|
if (zero) {
|
|
a = atomic_read(&cell->active);
|
|
WARN(a != 0, "Cell active count %u > 0\n", a);
|
|
call_rcu(&cell->rcu, afs_cell_destroy);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Note a cell becoming more active.
|
|
*/
|
|
struct afs_cell *afs_use_cell(struct afs_cell *cell, enum afs_cell_trace reason)
|
|
{
|
|
int r, a;
|
|
|
|
r = refcount_read(&cell->ref);
|
|
WARN_ON(r == 0);
|
|
a = atomic_inc_return(&cell->active);
|
|
trace_afs_cell(cell->debug_id, r, a, reason);
|
|
return cell;
|
|
}
|
|
|
|
/*
|
|
* Record a cell becoming less active. When the active counter reaches 1, it
|
|
* is scheduled for destruction, but may get reactivated.
|
|
*/
|
|
void afs_unuse_cell(struct afs_net *net, struct afs_cell *cell, enum afs_cell_trace reason)
|
|
{
|
|
unsigned int debug_id;
|
|
time64_t now, expire_delay;
|
|
int r, a;
|
|
|
|
if (!cell)
|
|
return;
|
|
|
|
_enter("%s", cell->name);
|
|
|
|
now = ktime_get_real_seconds();
|
|
cell->last_inactive = now;
|
|
expire_delay = 0;
|
|
if (cell->vl_servers->nr_servers)
|
|
expire_delay = afs_cell_gc_delay;
|
|
|
|
debug_id = cell->debug_id;
|
|
r = refcount_read(&cell->ref);
|
|
a = atomic_dec_return(&cell->active);
|
|
trace_afs_cell(debug_id, r, a, reason);
|
|
WARN_ON(a == 0);
|
|
if (a == 1)
|
|
/* 'cell' may now be garbage collected. */
|
|
afs_set_cell_timer(net, expire_delay);
|
|
}
|
|
|
|
/*
|
|
* Note that a cell has been seen.
|
|
*/
|
|
void afs_see_cell(struct afs_cell *cell, enum afs_cell_trace reason)
|
|
{
|
|
int r, a;
|
|
|
|
r = refcount_read(&cell->ref);
|
|
a = atomic_read(&cell->active);
|
|
trace_afs_cell(cell->debug_id, r, a, reason);
|
|
}
|
|
|
|
/*
|
|
* Queue a cell for management, giving the workqueue a ref to hold.
|
|
*/
|
|
void afs_queue_cell(struct afs_cell *cell, enum afs_cell_trace reason)
|
|
{
|
|
afs_get_cell(cell, reason);
|
|
if (!queue_work(afs_wq, &cell->manager))
|
|
afs_put_cell(cell, afs_cell_trace_put_queue_fail);
|
|
}
|
|
|
|
/*
|
|
* Allocate a key to use as a placeholder for anonymous user security.
|
|
*/
|
|
static int afs_alloc_anon_key(struct afs_cell *cell)
|
|
{
|
|
struct key *key;
|
|
char keyname[4 + AFS_MAXCELLNAME + 1], *cp, *dp;
|
|
|
|
/* Create a key to represent an anonymous user. */
|
|
memcpy(keyname, "afs@", 4);
|
|
dp = keyname + 4;
|
|
cp = cell->name;
|
|
do {
|
|
*dp++ = tolower(*cp);
|
|
} while (*cp++);
|
|
|
|
key = rxrpc_get_null_key(keyname);
|
|
if (IS_ERR(key))
|
|
return PTR_ERR(key);
|
|
|
|
cell->anonymous_key = key;
|
|
|
|
_debug("anon key %p{%x}",
|
|
cell->anonymous_key, key_serial(cell->anonymous_key));
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Activate a cell.
|
|
*/
|
|
static int afs_activate_cell(struct afs_net *net, struct afs_cell *cell)
|
|
{
|
|
struct hlist_node **p;
|
|
struct afs_cell *pcell;
|
|
int ret;
|
|
|
|
if (!cell->anonymous_key) {
|
|
ret = afs_alloc_anon_key(cell);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
ret = afs_proc_cell_setup(cell);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
mutex_lock(&net->proc_cells_lock);
|
|
for (p = &net->proc_cells.first; *p; p = &(*p)->next) {
|
|
pcell = hlist_entry(*p, struct afs_cell, proc_link);
|
|
if (strcmp(cell->name, pcell->name) < 0)
|
|
break;
|
|
}
|
|
|
|
cell->proc_link.pprev = p;
|
|
cell->proc_link.next = *p;
|
|
rcu_assign_pointer(*p, &cell->proc_link.next);
|
|
if (cell->proc_link.next)
|
|
cell->proc_link.next->pprev = &cell->proc_link.next;
|
|
|
|
afs_dynroot_mkdir(net, cell);
|
|
mutex_unlock(&net->proc_cells_lock);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Deactivate a cell.
|
|
*/
|
|
static void afs_deactivate_cell(struct afs_net *net, struct afs_cell *cell)
|
|
{
|
|
_enter("%s", cell->name);
|
|
|
|
afs_proc_cell_remove(cell);
|
|
|
|
mutex_lock(&net->proc_cells_lock);
|
|
hlist_del_rcu(&cell->proc_link);
|
|
afs_dynroot_rmdir(net, cell);
|
|
mutex_unlock(&net->proc_cells_lock);
|
|
|
|
_leave("");
|
|
}
|
|
|
|
/*
|
|
* Manage a cell record, initialising and destroying it, maintaining its DNS
|
|
* records.
|
|
*/
|
|
static void afs_manage_cell(struct afs_cell *cell)
|
|
{
|
|
struct afs_net *net = cell->net;
|
|
int ret, active;
|
|
|
|
_enter("%s", cell->name);
|
|
|
|
again:
|
|
_debug("state %u", cell->state);
|
|
switch (cell->state) {
|
|
case AFS_CELL_INACTIVE:
|
|
case AFS_CELL_FAILED:
|
|
down_write(&net->cells_lock);
|
|
active = 1;
|
|
if (atomic_try_cmpxchg_relaxed(&cell->active, &active, 0)) {
|
|
rb_erase(&cell->net_node, &net->cells);
|
|
trace_afs_cell(cell->debug_id, refcount_read(&cell->ref), 0,
|
|
afs_cell_trace_unuse_delete);
|
|
smp_store_release(&cell->state, AFS_CELL_REMOVED);
|
|
}
|
|
up_write(&net->cells_lock);
|
|
if (cell->state == AFS_CELL_REMOVED) {
|
|
wake_up_var(&cell->state);
|
|
goto final_destruction;
|
|
}
|
|
if (cell->state == AFS_CELL_FAILED)
|
|
goto done;
|
|
smp_store_release(&cell->state, AFS_CELL_UNSET);
|
|
wake_up_var(&cell->state);
|
|
goto again;
|
|
|
|
case AFS_CELL_UNSET:
|
|
smp_store_release(&cell->state, AFS_CELL_ACTIVATING);
|
|
wake_up_var(&cell->state);
|
|
goto again;
|
|
|
|
case AFS_CELL_ACTIVATING:
|
|
ret = afs_activate_cell(net, cell);
|
|
if (ret < 0)
|
|
goto activation_failed;
|
|
|
|
smp_store_release(&cell->state, AFS_CELL_ACTIVE);
|
|
wake_up_var(&cell->state);
|
|
goto again;
|
|
|
|
case AFS_CELL_ACTIVE:
|
|
if (atomic_read(&cell->active) > 1) {
|
|
if (test_and_clear_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags)) {
|
|
ret = afs_update_cell(cell);
|
|
if (ret < 0)
|
|
cell->error = ret;
|
|
}
|
|
goto done;
|
|
}
|
|
smp_store_release(&cell->state, AFS_CELL_DEACTIVATING);
|
|
wake_up_var(&cell->state);
|
|
goto again;
|
|
|
|
case AFS_CELL_DEACTIVATING:
|
|
if (atomic_read(&cell->active) > 1)
|
|
goto reverse_deactivation;
|
|
afs_deactivate_cell(net, cell);
|
|
smp_store_release(&cell->state, AFS_CELL_INACTIVE);
|
|
wake_up_var(&cell->state);
|
|
goto again;
|
|
|
|
case AFS_CELL_REMOVED:
|
|
goto done;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
_debug("bad state %u", cell->state);
|
|
BUG(); /* Unhandled state */
|
|
|
|
activation_failed:
|
|
cell->error = ret;
|
|
afs_deactivate_cell(net, cell);
|
|
|
|
smp_store_release(&cell->state, AFS_CELL_FAILED); /* vs error */
|
|
wake_up_var(&cell->state);
|
|
goto again;
|
|
|
|
reverse_deactivation:
|
|
smp_store_release(&cell->state, AFS_CELL_ACTIVE);
|
|
wake_up_var(&cell->state);
|
|
_leave(" [deact->act]");
|
|
return;
|
|
|
|
done:
|
|
_leave(" [done %u]", cell->state);
|
|
return;
|
|
|
|
final_destruction:
|
|
/* The root volume is pinning the cell */
|
|
afs_put_volume(cell->net, cell->root_volume, afs_volume_trace_put_cell_root);
|
|
cell->root_volume = NULL;
|
|
afs_put_cell(cell, afs_cell_trace_put_destroy);
|
|
}
|
|
|
|
static void afs_manage_cell_work(struct work_struct *work)
|
|
{
|
|
struct afs_cell *cell = container_of(work, struct afs_cell, manager);
|
|
|
|
afs_manage_cell(cell);
|
|
afs_put_cell(cell, afs_cell_trace_put_queue_work);
|
|
}
|
|
|
|
/*
|
|
* Manage the records of cells known to a network namespace. This includes
|
|
* updating the DNS records and garbage collecting unused cells that were
|
|
* automatically added.
|
|
*
|
|
* Note that constructed cell records may only be removed from net->cells by
|
|
* this work item, so it is safe for this work item to stash a cursor pointing
|
|
* into the tree and then return to caller (provided it skips cells that are
|
|
* still under construction).
|
|
*
|
|
* Note also that we were given an increment on net->cells_outstanding by
|
|
* whoever queued us that we need to deal with before returning.
|
|
*/
|
|
void afs_manage_cells(struct work_struct *work)
|
|
{
|
|
struct afs_net *net = container_of(work, struct afs_net, cells_manager);
|
|
struct rb_node *cursor;
|
|
time64_t now = ktime_get_real_seconds(), next_manage = TIME64_MAX;
|
|
bool purging = !net->live;
|
|
|
|
_enter("");
|
|
|
|
/* Trawl the cell database looking for cells that have expired from
|
|
* lack of use and cells whose DNS results have expired and dispatch
|
|
* their managers.
|
|
*/
|
|
down_read(&net->cells_lock);
|
|
|
|
for (cursor = rb_first(&net->cells); cursor; cursor = rb_next(cursor)) {
|
|
struct afs_cell *cell =
|
|
rb_entry(cursor, struct afs_cell, net_node);
|
|
unsigned active;
|
|
bool sched_cell = false;
|
|
|
|
active = atomic_read(&cell->active);
|
|
trace_afs_cell(cell->debug_id, refcount_read(&cell->ref),
|
|
active, afs_cell_trace_manage);
|
|
|
|
ASSERTCMP(active, >=, 1);
|
|
|
|
if (purging) {
|
|
if (test_and_clear_bit(AFS_CELL_FL_NO_GC, &cell->flags)) {
|
|
active = atomic_dec_return(&cell->active);
|
|
trace_afs_cell(cell->debug_id, refcount_read(&cell->ref),
|
|
active, afs_cell_trace_unuse_pin);
|
|
}
|
|
}
|
|
|
|
if (active == 1) {
|
|
struct afs_vlserver_list *vllist;
|
|
time64_t expire_at = cell->last_inactive;
|
|
|
|
read_lock(&cell->vl_servers_lock);
|
|
vllist = rcu_dereference_protected(
|
|
cell->vl_servers,
|
|
lockdep_is_held(&cell->vl_servers_lock));
|
|
if (vllist->nr_servers > 0)
|
|
expire_at += afs_cell_gc_delay;
|
|
read_unlock(&cell->vl_servers_lock);
|
|
if (purging || expire_at <= now)
|
|
sched_cell = true;
|
|
else if (expire_at < next_manage)
|
|
next_manage = expire_at;
|
|
}
|
|
|
|
if (!purging) {
|
|
if (test_bit(AFS_CELL_FL_DO_LOOKUP, &cell->flags))
|
|
sched_cell = true;
|
|
}
|
|
|
|
if (sched_cell)
|
|
afs_queue_cell(cell, afs_cell_trace_get_queue_manage);
|
|
}
|
|
|
|
up_read(&net->cells_lock);
|
|
|
|
/* Update the timer on the way out. We have to pass an increment on
|
|
* cells_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->cells_manager))
|
|
atomic_inc(&net->cells_outstanding);
|
|
} else {
|
|
afs_set_cell_timer(net, next_manage - now);
|
|
}
|
|
}
|
|
|
|
afs_dec_cells_outstanding(net);
|
|
_leave(" [%d]", atomic_read(&net->cells_outstanding));
|
|
}
|
|
|
|
/*
|
|
* Purge in-memory cell database.
|
|
*/
|
|
void afs_cell_purge(struct afs_net *net)
|
|
{
|
|
struct afs_cell *ws;
|
|
|
|
_enter("");
|
|
|
|
down_write(&net->cells_lock);
|
|
ws = net->ws_cell;
|
|
net->ws_cell = NULL;
|
|
up_write(&net->cells_lock);
|
|
afs_unuse_cell(net, ws, afs_cell_trace_unuse_ws);
|
|
|
|
_debug("del timer");
|
|
if (del_timer_sync(&net->cells_timer))
|
|
atomic_dec(&net->cells_outstanding);
|
|
|
|
_debug("kick mgr");
|
|
afs_queue_cell_manager(net);
|
|
|
|
_debug("wait");
|
|
wait_var_event(&net->cells_outstanding,
|
|
!atomic_read(&net->cells_outstanding));
|
|
_leave("");
|
|
}
|