![Jeff Layton](/assets/img/avatar_default.png)
If the nfsv4 callback thread is rapidly brought up and down, it's possible that nfs_callback_svc might never get a chance to run. If this happens, the cleanup at thread exit might never occur, throwing the refcounting off and nfs_callback_info in an incorrect state. Move the clean functions into nfs_callback_down. Also change the nfs_callback_info struct to track the svc_rqst rather than svc_serv since we need to know that to call svc_exit_thread. Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
220 lines
5.2 KiB
C
220 lines
5.2 KiB
C
/*
|
|
* linux/fs/nfs/callback.c
|
|
*
|
|
* Copyright (C) 2004 Trond Myklebust
|
|
*
|
|
* NFSv4 callback handling
|
|
*/
|
|
|
|
#include <linux/completion.h>
|
|
#include <linux/ip.h>
|
|
#include <linux/module.h>
|
|
#include <linux/smp_lock.h>
|
|
#include <linux/sunrpc/svc.h>
|
|
#include <linux/sunrpc/svcsock.h>
|
|
#include <linux/nfs_fs.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/freezer.h>
|
|
#include <linux/kthread.h>
|
|
|
|
#include <net/inet_sock.h>
|
|
|
|
#include "nfs4_fs.h"
|
|
#include "callback.h"
|
|
#include "internal.h"
|
|
|
|
#define NFSDBG_FACILITY NFSDBG_CALLBACK
|
|
|
|
struct nfs_callback_data {
|
|
unsigned int users;
|
|
struct svc_rqst *rqst;
|
|
struct task_struct *task;
|
|
};
|
|
|
|
static struct nfs_callback_data nfs_callback_info;
|
|
static DEFINE_MUTEX(nfs_callback_mutex);
|
|
static struct svc_program nfs4_callback_program;
|
|
|
|
unsigned int nfs_callback_set_tcpport;
|
|
unsigned short nfs_callback_tcpport;
|
|
static const int nfs_set_port_min = 0;
|
|
static const int nfs_set_port_max = 65535;
|
|
|
|
static int param_set_port(const char *val, struct kernel_param *kp)
|
|
{
|
|
char *endp;
|
|
int num = simple_strtol(val, &endp, 0);
|
|
if (endp == val || *endp || num < nfs_set_port_min || num > nfs_set_port_max)
|
|
return -EINVAL;
|
|
*((int *)kp->arg) = num;
|
|
return 0;
|
|
}
|
|
|
|
module_param_call(callback_tcpport, param_set_port, param_get_int,
|
|
&nfs_callback_set_tcpport, 0644);
|
|
|
|
/*
|
|
* This is the callback kernel thread.
|
|
*/
|
|
static int
|
|
nfs_callback_svc(void *vrqstp)
|
|
{
|
|
int err, preverr = 0;
|
|
struct svc_rqst *rqstp = vrqstp;
|
|
|
|
set_freezable();
|
|
|
|
/*
|
|
* FIXME: do we really need to run this under the BKL? If so, please
|
|
* add a comment about what it's intended to protect.
|
|
*/
|
|
lock_kernel();
|
|
while (!kthread_should_stop()) {
|
|
/*
|
|
* Listen for a request on the socket
|
|
*/
|
|
err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
|
|
if (err == -EAGAIN || err == -EINTR) {
|
|
preverr = err;
|
|
continue;
|
|
}
|
|
if (err < 0) {
|
|
if (err != preverr) {
|
|
printk(KERN_WARNING "%s: unexpected error "
|
|
"from svc_recv (%d)\n", __func__, err);
|
|
preverr = err;
|
|
}
|
|
schedule_timeout_uninterruptible(HZ);
|
|
continue;
|
|
}
|
|
preverr = err;
|
|
svc_process(rqstp);
|
|
}
|
|
unlock_kernel();
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Bring up the callback thread if it is not already up.
|
|
*/
|
|
int nfs_callback_up(void)
|
|
{
|
|
struct svc_serv *serv = NULL;
|
|
int ret = 0;
|
|
|
|
mutex_lock(&nfs_callback_mutex);
|
|
if (nfs_callback_info.users++ || nfs_callback_info.task != NULL)
|
|
goto out;
|
|
serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
|
|
ret = -ENOMEM;
|
|
if (!serv)
|
|
goto out_err;
|
|
|
|
ret = svc_create_xprt(serv, "tcp", nfs_callback_set_tcpport,
|
|
SVC_SOCK_ANONYMOUS);
|
|
if (ret <= 0)
|
|
goto out_err;
|
|
nfs_callback_tcpport = ret;
|
|
dprintk("Callback port = 0x%x\n", nfs_callback_tcpport);
|
|
|
|
nfs_callback_info.rqst = svc_prepare_thread(serv, &serv->sv_pools[0]);
|
|
if (IS_ERR(nfs_callback_info.rqst)) {
|
|
ret = PTR_ERR(nfs_callback_info.rqst);
|
|
nfs_callback_info.rqst = NULL;
|
|
goto out_err;
|
|
}
|
|
|
|
svc_sock_update_bufs(serv);
|
|
|
|
nfs_callback_info.task = kthread_run(nfs_callback_svc,
|
|
nfs_callback_info.rqst,
|
|
"nfsv4-svc");
|
|
if (IS_ERR(nfs_callback_info.task)) {
|
|
ret = PTR_ERR(nfs_callback_info.task);
|
|
svc_exit_thread(nfs_callback_info.rqst);
|
|
nfs_callback_info.rqst = NULL;
|
|
nfs_callback_info.task = NULL;
|
|
goto out_err;
|
|
}
|
|
out:
|
|
/*
|
|
* svc_create creates the svc_serv with sv_nrthreads == 1, and then
|
|
* svc_prepare_thread increments that. So we need to call svc_destroy
|
|
* on both success and failure so that the refcount is 1 when the
|
|
* thread exits.
|
|
*/
|
|
if (serv)
|
|
svc_destroy(serv);
|
|
mutex_unlock(&nfs_callback_mutex);
|
|
return ret;
|
|
out_err:
|
|
dprintk("Couldn't create callback socket or server thread; err = %d\n",
|
|
ret);
|
|
nfs_callback_info.users--;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Kill the callback thread if it's no longer being used.
|
|
*/
|
|
void nfs_callback_down(void)
|
|
{
|
|
mutex_lock(&nfs_callback_mutex);
|
|
nfs_callback_info.users--;
|
|
if (nfs_callback_info.users == 0 && nfs_callback_info.task != NULL) {
|
|
kthread_stop(nfs_callback_info.task);
|
|
svc_exit_thread(nfs_callback_info.rqst);
|
|
nfs_callback_info.rqst = NULL;
|
|
nfs_callback_info.task = NULL;
|
|
}
|
|
mutex_unlock(&nfs_callback_mutex);
|
|
}
|
|
|
|
static int nfs_callback_authenticate(struct svc_rqst *rqstp)
|
|
{
|
|
struct nfs_client *clp;
|
|
RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
|
|
|
|
/* Don't talk to strangers */
|
|
clp = nfs_find_client(svc_addr(rqstp), 4);
|
|
if (clp == NULL)
|
|
return SVC_DROP;
|
|
|
|
dprintk("%s: %s NFSv4 callback!\n", __func__,
|
|
svc_print_addr(rqstp, buf, sizeof(buf)));
|
|
nfs_put_client(clp);
|
|
|
|
switch (rqstp->rq_authop->flavour) {
|
|
case RPC_AUTH_NULL:
|
|
if (rqstp->rq_proc != CB_NULL)
|
|
return SVC_DENIED;
|
|
break;
|
|
case RPC_AUTH_UNIX:
|
|
break;
|
|
case RPC_AUTH_GSS:
|
|
/* FIXME: RPCSEC_GSS handling? */
|
|
default:
|
|
return SVC_DENIED;
|
|
}
|
|
return SVC_OK;
|
|
}
|
|
|
|
/*
|
|
* Define NFS4 callback program
|
|
*/
|
|
static struct svc_version *nfs4_callback_version[] = {
|
|
[1] = &nfs4_callback_version1,
|
|
};
|
|
|
|
static struct svc_stat nfs4_callback_stats;
|
|
|
|
static struct svc_program nfs4_callback_program = {
|
|
.pg_prog = NFS4_CALLBACK, /* RPC service number */
|
|
.pg_nvers = ARRAY_SIZE(nfs4_callback_version), /* Number of entries */
|
|
.pg_vers = nfs4_callback_version, /* version table */
|
|
.pg_name = "NFSv4 callback", /* service name */
|
|
.pg_class = "nfs", /* authentication class */
|
|
.pg_stats = &nfs4_callback_stats,
|
|
.pg_authenticate = nfs_callback_authenticate,
|
|
};
|