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alistair23-linux/fs/afs/main.c
David Howells 6b3944e42e afs: Fix cell proc list 
Access to the list of cells by /proc/net/afs/cells has a couple of
problems:

 (1) It should be checking against SEQ_START_TOKEN for the keying the
     header line.

 (2) It's only holding the RCU read lock, so it can't just walk over the
     list without following the proper RCU methods.

Fix these by using an hlist instead of an ordinary list and using the
appropriate accessor functions to follow it with RCU.

Since the code that adds a cell to the list must also necessarily change,
sort the list on insertion whilst we're at it.

Fixes: 989782dcdc ("afs: Overhaul cell database management")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-10-12 13:18:57 +02:00

256 lines
6.3 KiB
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/* AFS client file system
*
* Copyright (C) 2002,5 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/sched.h>
#include <linux/random.h>
#include <linux/proc_fs.h>
#define CREATE_TRACE_POINTS
#include "internal.h"
MODULE_DESCRIPTION("AFS Client File System");
MODULE_AUTHOR("Red Hat, Inc.");
MODULE_LICENSE("GPL");
unsigned afs_debug;
module_param_named(debug, afs_debug, uint, S_IWUSR | S_IRUGO);
MODULE_PARM_DESC(debug, "AFS debugging mask");
static char *rootcell;
module_param(rootcell, charp, 0);
MODULE_PARM_DESC(rootcell, "root AFS cell name and VL server IP addr list");
struct workqueue_struct *afs_wq;
static struct proc_dir_entry *afs_proc_symlink;
#if defined(CONFIG_ALPHA)
const char afs_init_sysname[] = "alpha_linux26";
#elif defined(CONFIG_X86_64)
const char afs_init_sysname[] = "amd64_linux26";
#elif defined(CONFIG_ARM)
const char afs_init_sysname[] = "arm_linux26";
#elif defined(CONFIG_ARM64)
const char afs_init_sysname[] = "aarch64_linux26";
#elif defined(CONFIG_X86_32)
const char afs_init_sysname[] = "i386_linux26";
#elif defined(CONFIG_IA64)
const char afs_init_sysname[] = "ia64_linux26";
#elif defined(CONFIG_PPC64)
const char afs_init_sysname[] = "ppc64_linux26";
#elif defined(CONFIG_PPC32)
const char afs_init_sysname[] = "ppc_linux26";
#elif defined(CONFIG_S390)
#ifdef CONFIG_64BIT
const char afs_init_sysname[] = "s390x_linux26";
#else
const char afs_init_sysname[] = "s390_linux26";
#endif
#elif defined(CONFIG_SPARC64)
const char afs_init_sysname[] = "sparc64_linux26";
#elif defined(CONFIG_SPARC32)
const char afs_init_sysname[] = "sparc_linux26";
#else
const char afs_init_sysname[] = "unknown_linux26";
#endif
/*
* Initialise an AFS network namespace record.
*/
static int __net_init afs_net_init(struct net *net_ns)
{
struct afs_sysnames *sysnames;
struct afs_net *net = afs_net(net_ns);
int ret;
net->net = net_ns;
net->live = true;
generate_random_uuid((unsigned char *)&net->uuid);
INIT_WORK(&net->charge_preallocation_work, afs_charge_preallocation);
mutex_init(&net->socket_mutex);
net->cells = RB_ROOT;
seqlock_init(&net->cells_lock);
INIT_WORK(&net->cells_manager, afs_manage_cells);
timer_setup(&net->cells_timer, afs_cells_timer, 0);
mutex_init(&net->proc_cells_lock);
INIT_HLIST_HEAD(&net->proc_cells);
seqlock_init(&net->fs_lock);
net->fs_servers = RB_ROOT;
INIT_LIST_HEAD(&net->fs_updates);
INIT_HLIST_HEAD(&net->fs_proc);
INIT_HLIST_HEAD(&net->fs_addresses4);
INIT_HLIST_HEAD(&net->fs_addresses6);
seqlock_init(&net->fs_addr_lock);
INIT_WORK(&net->fs_manager, afs_manage_servers);
timer_setup(&net->fs_timer, afs_servers_timer, 0);
ret = -ENOMEM;
sysnames = kzalloc(sizeof(*sysnames), GFP_KERNEL);
if (!sysnames)
goto error_sysnames;
sysnames->subs[0] = (char *)&afs_init_sysname;
sysnames->nr = 1;
refcount_set(&sysnames->usage, 1);
net->sysnames = sysnames;
rwlock_init(&net->sysnames_lock);
/* Register the /proc stuff */
ret = afs_proc_init(net);
if (ret < 0)
goto error_proc;
/* Initialise the cell DB */
ret = afs_cell_init(net, rootcell);
if (ret < 0)
goto error_cell_init;
/* Create the RxRPC transport */
ret = afs_open_socket(net);
if (ret < 0)
goto error_open_socket;
return 0;
error_open_socket:
net->live = false;
afs_cell_purge(net);
afs_purge_servers(net);
error_cell_init:
net->live = false;
afs_proc_cleanup(net);
error_proc:
afs_put_sysnames(net->sysnames);
error_sysnames:
net->live = false;
return ret;
}
/*
* Clean up and destroy an AFS network namespace record.
*/
static void __net_exit afs_net_exit(struct net *net_ns)
{
struct afs_net *net = afs_net(net_ns);
net->live = false;
afs_cell_purge(net);
afs_purge_servers(net);
afs_close_socket(net);
afs_proc_cleanup(net);
afs_put_sysnames(net->sysnames);
}
static struct pernet_operations afs_net_ops = {
.init = afs_net_init,
.exit = afs_net_exit,
.id = &afs_net_id,
.size = sizeof(struct afs_net),
};
/*
* initialise the AFS client FS module
*/
static int __init afs_init(void)
{
int ret = -ENOMEM;
printk(KERN_INFO "kAFS: Red Hat AFS client v0.1 registering.\n");
afs_wq = alloc_workqueue("afs", 0, 0);
if (!afs_wq)
goto error_afs_wq;
afs_async_calls = alloc_workqueue("kafsd", WQ_MEM_RECLAIM, 0);
if (!afs_async_calls)
goto error_async;
afs_lock_manager = alloc_workqueue("kafs_lockd", WQ_MEM_RECLAIM, 0);
if (!afs_lock_manager)
goto error_lockmgr;
#ifdef CONFIG_AFS_FSCACHE
/* we want to be able to cache */
ret = fscache_register_netfs(&afs_cache_netfs);
if (ret < 0)
goto error_cache;
#endif
ret = register_pernet_subsys(&afs_net_ops);
if (ret < 0)
goto error_net;
/* register the filesystems */
ret = afs_fs_init();
if (ret < 0)
goto error_fs;
afs_proc_symlink = proc_symlink("fs/afs", NULL, "../self/net/afs");
if (IS_ERR(afs_proc_symlink)) {
ret = PTR_ERR(afs_proc_symlink);
goto error_proc;
}
return ret;
error_proc:
afs_fs_exit();
error_fs:
unregister_pernet_subsys(&afs_net_ops);
error_net:
#ifdef CONFIG_AFS_FSCACHE
fscache_unregister_netfs(&afs_cache_netfs);
error_cache:
#endif
destroy_workqueue(afs_lock_manager);
error_lockmgr:
destroy_workqueue(afs_async_calls);
error_async:
destroy_workqueue(afs_wq);
error_afs_wq:
rcu_barrier();
printk(KERN_ERR "kAFS: failed to register: %d\n", ret);
return ret;
}
/* XXX late_initcall is kludgy, but the only alternative seems to create
* a transport upon the first mount, which is worse. Or is it?
*/
late_initcall(afs_init); /* must be called after net/ to create socket */
/*
* clean up on module removal
*/
static void __exit afs_exit(void)
{
printk(KERN_INFO "kAFS: Red Hat AFS client v0.1 unregistering.\n");
proc_remove(afs_proc_symlink);
afs_fs_exit();
unregister_pernet_subsys(&afs_net_ops);
#ifdef CONFIG_AFS_FSCACHE
fscache_unregister_netfs(&afs_cache_netfs);
#endif
destroy_workqueue(afs_lock_manager);
destroy_workqueue(afs_async_calls);
destroy_workqueue(afs_wq);
afs_clean_up_permit_cache();
rcu_barrier();
}
module_exit(afs_exit);
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