Merge commit 'v2.6.28-rc2' into core/locking
[linux-2.6] / fs / nfs / callback.c
1 /*
2  * linux/fs/nfs/callback.c
3  *
4  * Copyright (C) 2004 Trond Myklebust
5  *
6  * NFSv4 callback handling
7  */
8
9 #include <linux/completion.h>
10 #include <linux/ip.h>
11 #include <linux/module.h>
12 #include <linux/smp_lock.h>
13 #include <linux/sunrpc/svc.h>
14 #include <linux/sunrpc/svcsock.h>
15 #include <linux/nfs_fs.h>
16 #include <linux/mutex.h>
17 #include <linux/freezer.h>
18 #include <linux/kthread.h>
19
20 #include <net/inet_sock.h>
21
22 #include "nfs4_fs.h"
23 #include "callback.h"
24 #include "internal.h"
25
26 #define NFSDBG_FACILITY NFSDBG_CALLBACK
27
28 struct nfs_callback_data {
29         unsigned int users;
30         struct svc_rqst *rqst;
31         struct task_struct *task;
32 };
33
34 static struct nfs_callback_data nfs_callback_info;
35 static DEFINE_MUTEX(nfs_callback_mutex);
36 static struct svc_program nfs4_callback_program;
37
38 unsigned int nfs_callback_set_tcpport;
39 unsigned short nfs_callback_tcpport;
40 static const int nfs_set_port_min = 0;
41 static const int nfs_set_port_max = 65535;
42
43 /*
44  * If the kernel has IPv6 support available, always listen for
45  * both AF_INET and AF_INET6 requests.
46  */
47 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
48 static const sa_family_t        nfs_callback_family = AF_INET6;
49 #else
50 static const sa_family_t        nfs_callback_family = AF_INET;
51 #endif
52
53 static int param_set_port(const char *val, struct kernel_param *kp)
54 {
55         char *endp;
56         int num = simple_strtol(val, &endp, 0);
57         if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max)
58                 return -EINVAL;
59         *((int *)kp->arg) = num;
60         return 0;
61 }
62
63 module_param_call(callback_tcpport, param_set_port, param_get_int,
64                  &nfs_callback_set_tcpport, 0644);
65
66 /*
67  * This is the callback kernel thread.
68  */
69 static int
70 nfs_callback_svc(void *vrqstp)
71 {
72         int err, preverr = 0;
73         struct svc_rqst *rqstp = vrqstp;
74
75         set_freezable();
76
77         /*
78          * FIXME: do we really need to run this under the BKL? If so, please
79          * add a comment about what it's intended to protect.
80          */
81         lock_kernel();
82         while (!kthread_should_stop()) {
83                 /*
84                  * Listen for a request on the socket
85                  */
86                 err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
87                 if (err == -EAGAIN || err == -EINTR) {
88                         preverr = err;
89                         continue;
90                 }
91                 if (err < 0) {
92                         if (err != preverr) {
93                                 printk(KERN_WARNING "%s: unexpected error "
94                                         "from svc_recv (%d)\n", __func__, err);
95                                 preverr = err;
96                         }
97                         schedule_timeout_uninterruptible(HZ);
98                         continue;
99                 }
100                 preverr = err;
101                 svc_process(rqstp);
102         }
103         unlock_kernel();
104         return 0;
105 }
106
107 /*
108  * Bring up the callback thread if it is not already up.
109  */
110 int nfs_callback_up(void)
111 {
112         struct svc_serv *serv = NULL;
113         int ret = 0;
114
115         mutex_lock(&nfs_callback_mutex);
116         if (nfs_callback_info.users++ || nfs_callback_info.task != NULL)
117                 goto out;
118         serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE,
119                                 nfs_callback_family, NULL);
120         ret = -ENOMEM;
121         if (!serv)
122                 goto out_err;
123
124         ret = svc_create_xprt(serv, "tcp", nfs_callback_set_tcpport,
125                               SVC_SOCK_ANONYMOUS);
126         if (ret <= 0)
127                 goto out_err;
128         nfs_callback_tcpport = ret;
129         dprintk("NFS: Callback listener port = %u (af %u)\n",
130                         nfs_callback_tcpport, nfs_callback_family);
131
132         nfs_callback_info.rqst = svc_prepare_thread(serv, &serv->sv_pools[0]);
133         if (IS_ERR(nfs_callback_info.rqst)) {
134                 ret = PTR_ERR(nfs_callback_info.rqst);
135                 nfs_callback_info.rqst = NULL;
136                 goto out_err;
137         }
138
139         svc_sock_update_bufs(serv);
140
141         nfs_callback_info.task = kthread_run(nfs_callback_svc,
142                                              nfs_callback_info.rqst,
143                                              "nfsv4-svc");
144         if (IS_ERR(nfs_callback_info.task)) {
145                 ret = PTR_ERR(nfs_callback_info.task);
146                 svc_exit_thread(nfs_callback_info.rqst);
147                 nfs_callback_info.rqst = NULL;
148                 nfs_callback_info.task = NULL;
149                 goto out_err;
150         }
151 out:
152         /*
153          * svc_create creates the svc_serv with sv_nrthreads == 1, and then
154          * svc_prepare_thread increments that. So we need to call svc_destroy
155          * on both success and failure so that the refcount is 1 when the
156          * thread exits.
157          */
158         if (serv)
159                 svc_destroy(serv);
160         mutex_unlock(&nfs_callback_mutex);
161         return ret;
162 out_err:
163         dprintk("NFS: Couldn't create callback socket or server thread; "
164                 "err = %d\n", ret);
165         nfs_callback_info.users--;
166         goto out;
167 }
168
169 /*
170  * Kill the callback thread if it's no longer being used.
171  */
172 void nfs_callback_down(void)
173 {
174         mutex_lock(&nfs_callback_mutex);
175         nfs_callback_info.users--;
176         if (nfs_callback_info.users == 0 && nfs_callback_info.task != NULL) {
177                 kthread_stop(nfs_callback_info.task);
178                 svc_exit_thread(nfs_callback_info.rqst);
179                 nfs_callback_info.rqst = NULL;
180                 nfs_callback_info.task = NULL;
181         }
182         mutex_unlock(&nfs_callback_mutex);
183 }
184
185 static int nfs_callback_authenticate(struct svc_rqst *rqstp)
186 {
187         struct nfs_client *clp;
188         RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
189
190         /* Don't talk to strangers */
191         clp = nfs_find_client(svc_addr(rqstp), 4);
192         if (clp == NULL)
193                 return SVC_DROP;
194
195         dprintk("%s: %s NFSv4 callback!\n", __func__,
196                         svc_print_addr(rqstp, buf, sizeof(buf)));
197         nfs_put_client(clp);
198
199         switch (rqstp->rq_authop->flavour) {
200                 case RPC_AUTH_NULL:
201                         if (rqstp->rq_proc != CB_NULL)
202                                 return SVC_DENIED;
203                         break;
204                 case RPC_AUTH_UNIX:
205                         break;
206                 case RPC_AUTH_GSS:
207                         /* FIXME: RPCSEC_GSS handling? */
208                 default:
209                         return SVC_DENIED;
210         }
211         return SVC_OK;
212 }
213
214 /*
215  * Define NFS4 callback program
216  */
217 static struct svc_version *nfs4_callback_version[] = {
218         [1] = &nfs4_callback_version1,
219 };
220
221 static struct svc_stat nfs4_callback_stats;
222
223 static struct svc_program nfs4_callback_program = {
224         .pg_prog = NFS4_CALLBACK,                       /* RPC service number */
225         .pg_nvers = ARRAY_SIZE(nfs4_callback_version),  /* Number of entries */
226         .pg_vers = nfs4_callback_version,               /* version table */
227         .pg_name = "NFSv4 callback",                    /* service name */
228         .pg_class = "nfs",                              /* authentication class */
229         .pg_stats = &nfs4_callback_stats,
230         .pg_authenticate = nfs_callback_authenticate,
231 };