linux/fs/lockd/svc.c
Marc Eshel 9a8db97e77 knfsd: lockd: nfsd4: use same grace period for lockd and nfsd4
Both lockd and (in the nfsv4 case) nfsd enforce a "grace period" after reboot,
during which clients may reclaim locks from the previous server instance, but
may not acquire new locks.

Currently the lockd and nfsd enforce grace periods of different lengths.  This
may cause problems when we reboot a server with both v2/v3 and v4 clients.
For example, if the lockd grace period is shorter (as is likely the case),
then a v3 client might acquire a new lock that conflicts with a lock already
held (but not yet reclaimed) by a v4 client.

This patch calculates a lease time that lockd and nfsd can both use.

Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 10:23:07 -07:00

581 lines
14 KiB
C

/*
* linux/fs/lockd/svc.c
*
* This is the central lockd service.
*
* FIXME: Separate the lockd NFS server functionality from the lockd NFS
* client functionality. Oh why didn't Sun create two separate
* services in the first place?
*
* Authors: Olaf Kirch (okir@monad.swb.de)
*
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/uio.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/mutex.h>
#include <linux/freezer.h>
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/svcsock.h>
#include <net/ip.h>
#include <linux/lockd/lockd.h>
#include <linux/lockd/sm_inter.h>
#include <linux/nfs.h>
#define NLMDBG_FACILITY NLMDBG_SVC
#define LOCKD_BUFSIZE (1024 + NLMSVC_XDRSIZE)
#define ALLOWED_SIGS (sigmask(SIGKILL))
static struct svc_program nlmsvc_program;
struct nlmsvc_binding * nlmsvc_ops;
EXPORT_SYMBOL(nlmsvc_ops);
static DEFINE_MUTEX(nlmsvc_mutex);
static unsigned int nlmsvc_users;
static pid_t nlmsvc_pid;
static struct svc_serv *nlmsvc_serv;
int nlmsvc_grace_period;
unsigned long nlmsvc_timeout;
static DECLARE_COMPLETION(lockd_start_done);
static DECLARE_WAIT_QUEUE_HEAD(lockd_exit);
/*
* These can be set at insmod time (useful for NFS as root filesystem),
* and also changed through the sysctl interface. -- Jamie Lokier, Aug 2003
*/
static unsigned long nlm_grace_period;
static unsigned long nlm_timeout = LOCKD_DFLT_TIMEO;
static int nlm_udpport, nlm_tcpport;
int nsm_use_hostnames = 0;
/*
* Constants needed for the sysctl interface.
*/
static const unsigned long nlm_grace_period_min = 0;
static const unsigned long nlm_grace_period_max = 240;
static const unsigned long nlm_timeout_min = 3;
static const unsigned long nlm_timeout_max = 20;
static const int nlm_port_min = 0, nlm_port_max = 65535;
static struct ctl_table_header * nlm_sysctl_table;
static unsigned long get_lockd_grace_period(void)
{
/* Note: nlm_timeout should always be nonzero */
if (nlm_grace_period)
return roundup(nlm_grace_period, nlm_timeout) * HZ;
else
return nlm_timeout * 5 * HZ;
}
unsigned long get_nfs_grace_period(void)
{
unsigned long lockdgrace = get_lockd_grace_period();
unsigned long nfsdgrace = 0;
if (nlmsvc_ops)
nfsdgrace = nlmsvc_ops->get_grace_period();
return max(lockdgrace, nfsdgrace);
}
EXPORT_SYMBOL(get_nfs_grace_period);
static unsigned long set_grace_period(void)
{
nlmsvc_grace_period = 1;
return get_nfs_grace_period() + jiffies;
}
static inline void clear_grace_period(void)
{
nlmsvc_grace_period = 0;
}
/*
* This is the lockd kernel thread
*/
static void
lockd(struct svc_rqst *rqstp)
{
int err = 0;
unsigned long grace_period_expire;
/* Lock module and set up kernel thread */
/* lockd_up is waiting for us to startup, so will
* be holding a reference to this module, so it
* is safe to just claim another reference
*/
__module_get(THIS_MODULE);
lock_kernel();
/*
* Let our maker know we're running.
*/
nlmsvc_pid = current->pid;
nlmsvc_serv = rqstp->rq_server;
complete(&lockd_start_done);
daemonize("lockd");
set_freezable();
/* Process request with signals blocked, but allow SIGKILL. */
allow_signal(SIGKILL);
dprintk("NFS locking service started (ver " LOCKD_VERSION ").\n");
if (!nlm_timeout)
nlm_timeout = LOCKD_DFLT_TIMEO;
nlmsvc_timeout = nlm_timeout * HZ;
grace_period_expire = set_grace_period();
/*
* The main request loop. We don't terminate until the last
* NFS mount or NFS daemon has gone away, and we've been sent a
* signal, or else another process has taken over our job.
*/
while ((nlmsvc_users || !signalled()) && nlmsvc_pid == current->pid) {
long timeout = MAX_SCHEDULE_TIMEOUT;
char buf[RPC_MAX_ADDRBUFLEN];
if (signalled()) {
flush_signals(current);
if (nlmsvc_ops) {
nlmsvc_invalidate_all();
grace_period_expire = set_grace_period();
}
}
/*
* Retry any blocked locks that have been notified by
* the VFS. Don't do this during grace period.
* (Theoretically, there shouldn't even be blocked locks
* during grace period).
*/
if (!nlmsvc_grace_period) {
timeout = nlmsvc_retry_blocked();
} else if (time_before(grace_period_expire, jiffies))
clear_grace_period();
/*
* Find a socket with data available and call its
* recvfrom routine.
*/
err = svc_recv(rqstp, timeout);
if (err == -EAGAIN || err == -EINTR)
continue;
if (err < 0) {
printk(KERN_WARNING
"lockd: terminating on error %d\n",
-err);
break;
}
dprintk("lockd: request from %s\n",
svc_print_addr(rqstp, buf, sizeof(buf)));
svc_process(rqstp);
}
flush_signals(current);
/*
* Check whether there's a new lockd process before
* shutting down the hosts and clearing the slot.
*/
if (!nlmsvc_pid || current->pid == nlmsvc_pid) {
if (nlmsvc_ops)
nlmsvc_invalidate_all();
nlm_shutdown_hosts();
nlmsvc_pid = 0;
nlmsvc_serv = NULL;
} else
printk(KERN_DEBUG
"lockd: new process, skipping host shutdown\n");
wake_up(&lockd_exit);
/* Exit the RPC thread */
svc_exit_thread(rqstp);
/* Release module */
unlock_kernel();
module_put_and_exit(0);
}
static int find_socket(struct svc_serv *serv, int proto)
{
struct svc_sock *svsk;
int found = 0;
list_for_each_entry(svsk, &serv->sv_permsocks, sk_list)
if (svsk->sk_sk->sk_protocol == proto) {
found = 1;
break;
}
return found;
}
/*
* Make any sockets that are needed but not present.
* If nlm_udpport or nlm_tcpport were set as module
* options, make those sockets unconditionally
*/
static int make_socks(struct svc_serv *serv, int proto)
{
static int warned;
int err = 0;
if (proto == IPPROTO_UDP || nlm_udpport)
if (!find_socket(serv, IPPROTO_UDP))
err = svc_makesock(serv, IPPROTO_UDP, nlm_udpport,
SVC_SOCK_DEFAULTS);
if (err >= 0 && (proto == IPPROTO_TCP || nlm_tcpport))
if (!find_socket(serv, IPPROTO_TCP))
err = svc_makesock(serv, IPPROTO_TCP, nlm_tcpport,
SVC_SOCK_DEFAULTS);
if (err >= 0) {
warned = 0;
err = 0;
} else if (warned++ == 0)
printk(KERN_WARNING
"lockd_up: makesock failed, error=%d\n", err);
return err;
}
/*
* Bring up the lockd process if it's not already up.
*/
int
lockd_up(int proto) /* Maybe add a 'family' option when IPv6 is supported ?? */
{
struct svc_serv * serv;
int error = 0;
mutex_lock(&nlmsvc_mutex);
/*
* Check whether we're already up and running.
*/
if (nlmsvc_pid) {
if (proto)
error = make_socks(nlmsvc_serv, proto);
goto out;
}
/*
* Sanity check: if there's no pid,
* we should be the first user ...
*/
if (nlmsvc_users)
printk(KERN_WARNING
"lockd_up: no pid, %d users??\n", nlmsvc_users);
error = -ENOMEM;
serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);
if (!serv) {
printk(KERN_WARNING "lockd_up: create service failed\n");
goto out;
}
if ((error = make_socks(serv, proto)) < 0)
goto destroy_and_out;
/*
* Create the kernel thread and wait for it to start.
*/
error = svc_create_thread(lockd, serv);
if (error) {
printk(KERN_WARNING
"lockd_up: create thread failed, error=%d\n", error);
goto destroy_and_out;
}
wait_for_completion(&lockd_start_done);
/*
* Note: svc_serv structures have an initial use count of 1,
* so we exit through here on both success and failure.
*/
destroy_and_out:
svc_destroy(serv);
out:
if (!error)
nlmsvc_users++;
mutex_unlock(&nlmsvc_mutex);
return error;
}
EXPORT_SYMBOL(lockd_up);
/*
* Decrement the user count and bring down lockd if we're the last.
*/
void
lockd_down(void)
{
static int warned;
mutex_lock(&nlmsvc_mutex);
if (nlmsvc_users) {
if (--nlmsvc_users)
goto out;
} else
printk(KERN_WARNING "lockd_down: no users! pid=%d\n", nlmsvc_pid);
if (!nlmsvc_pid) {
if (warned++ == 0)
printk(KERN_WARNING "lockd_down: no lockd running.\n");
goto out;
}
warned = 0;
kill_proc(nlmsvc_pid, SIGKILL, 1);
/*
* Wait for the lockd process to exit, but since we're holding
* the lockd semaphore, we can't wait around forever ...
*/
clear_thread_flag(TIF_SIGPENDING);
interruptible_sleep_on_timeout(&lockd_exit, HZ);
if (nlmsvc_pid) {
printk(KERN_WARNING
"lockd_down: lockd failed to exit, clearing pid\n");
nlmsvc_pid = 0;
}
spin_lock_irq(&current->sighand->siglock);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
out:
mutex_unlock(&nlmsvc_mutex);
}
EXPORT_SYMBOL(lockd_down);
/*
* Sysctl parameters (same as module parameters, different interface).
*/
static ctl_table nlm_sysctls[] = {
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nlm_grace_period",
.data = &nlm_grace_period,
.maxlen = sizeof(unsigned long),
.mode = 0644,
.proc_handler = &proc_doulongvec_minmax,
.extra1 = (unsigned long *) &nlm_grace_period_min,
.extra2 = (unsigned long *) &nlm_grace_period_max,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nlm_timeout",
.data = &nlm_timeout,
.maxlen = sizeof(unsigned long),
.mode = 0644,
.proc_handler = &proc_doulongvec_minmax,
.extra1 = (unsigned long *) &nlm_timeout_min,
.extra2 = (unsigned long *) &nlm_timeout_max,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nlm_udpport",
.data = &nlm_udpport,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.extra1 = (int *) &nlm_port_min,
.extra2 = (int *) &nlm_port_max,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nlm_tcpport",
.data = &nlm_tcpport,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec_minmax,
.extra1 = (int *) &nlm_port_min,
.extra2 = (int *) &nlm_port_max,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nsm_use_hostnames",
.data = &nsm_use_hostnames,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec,
},
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nsm_local_state",
.data = &nsm_local_state,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec,
},
{ .ctl_name = 0 }
};
static ctl_table nlm_sysctl_dir[] = {
{
.ctl_name = CTL_UNNUMBERED,
.procname = "nfs",
.mode = 0555,
.child = nlm_sysctls,
},
{ .ctl_name = 0 }
};
static ctl_table nlm_sysctl_root[] = {
{
.ctl_name = CTL_FS,
.procname = "fs",
.mode = 0555,
.child = nlm_sysctl_dir,
},
{ .ctl_name = 0 }
};
/*
* Module (and sysfs) parameters.
*/
#define param_set_min_max(name, type, which_strtol, min, max) \
static int param_set_##name(const char *val, struct kernel_param *kp) \
{ \
char *endp; \
__typeof__(type) num = which_strtol(val, &endp, 0); \
if (endp == val || *endp || num < (min) || num > (max)) \
return -EINVAL; \
*((int *) kp->arg) = num; \
return 0; \
}
static inline int is_callback(u32 proc)
{
return proc == NLMPROC_GRANTED
|| proc == NLMPROC_GRANTED_MSG
|| proc == NLMPROC_TEST_RES
|| proc == NLMPROC_LOCK_RES
|| proc == NLMPROC_CANCEL_RES
|| proc == NLMPROC_UNLOCK_RES
|| proc == NLMPROC_NSM_NOTIFY;
}
static int lockd_authenticate(struct svc_rqst *rqstp)
{
rqstp->rq_client = NULL;
switch (rqstp->rq_authop->flavour) {
case RPC_AUTH_NULL:
case RPC_AUTH_UNIX:
if (rqstp->rq_proc == 0)
return SVC_OK;
if (is_callback(rqstp->rq_proc)) {
/* Leave it to individual procedures to
* call nlmsvc_lookup_host(rqstp)
*/
return SVC_OK;
}
return svc_set_client(rqstp);
}
return SVC_DENIED;
}
param_set_min_max(port, int, simple_strtol, 0, 65535)
param_set_min_max(grace_period, unsigned long, simple_strtoul,
nlm_grace_period_min, nlm_grace_period_max)
param_set_min_max(timeout, unsigned long, simple_strtoul,
nlm_timeout_min, nlm_timeout_max)
MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
MODULE_DESCRIPTION("NFS file locking service version " LOCKD_VERSION ".");
MODULE_LICENSE("GPL");
module_param_call(nlm_grace_period, param_set_grace_period, param_get_ulong,
&nlm_grace_period, 0644);
module_param_call(nlm_timeout, param_set_timeout, param_get_ulong,
&nlm_timeout, 0644);
module_param_call(nlm_udpport, param_set_port, param_get_int,
&nlm_udpport, 0644);
module_param_call(nlm_tcpport, param_set_port, param_get_int,
&nlm_tcpport, 0644);
module_param(nsm_use_hostnames, bool, 0644);
/*
* Initialising and terminating the module.
*/
static int __init init_nlm(void)
{
nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root);
return nlm_sysctl_table ? 0 : -ENOMEM;
}
static void __exit exit_nlm(void)
{
/* FIXME: delete all NLM clients */
nlm_shutdown_hosts();
unregister_sysctl_table(nlm_sysctl_table);
}
module_init(init_nlm);
module_exit(exit_nlm);
/*
* Define NLM program and procedures
*/
static struct svc_version nlmsvc_version1 = {
.vs_vers = 1,
.vs_nproc = 17,
.vs_proc = nlmsvc_procedures,
.vs_xdrsize = NLMSVC_XDRSIZE,
};
static struct svc_version nlmsvc_version3 = {
.vs_vers = 3,
.vs_nproc = 24,
.vs_proc = nlmsvc_procedures,
.vs_xdrsize = NLMSVC_XDRSIZE,
};
#ifdef CONFIG_LOCKD_V4
static struct svc_version nlmsvc_version4 = {
.vs_vers = 4,
.vs_nproc = 24,
.vs_proc = nlmsvc_procedures4,
.vs_xdrsize = NLMSVC_XDRSIZE,
};
#endif
static struct svc_version * nlmsvc_version[] = {
[1] = &nlmsvc_version1,
[3] = &nlmsvc_version3,
#ifdef CONFIG_LOCKD_V4
[4] = &nlmsvc_version4,
#endif
};
static struct svc_stat nlmsvc_stats;
#define NLM_NRVERS ARRAY_SIZE(nlmsvc_version)
static struct svc_program nlmsvc_program = {
.pg_prog = NLM_PROGRAM, /* program number */
.pg_nvers = NLM_NRVERS, /* number of entries in nlmsvc_version */
.pg_vers = nlmsvc_version, /* version table */
.pg_name = "lockd", /* service name */
.pg_class = "nfsd", /* share authentication with nfsd */
.pg_stats = &nlmsvc_stats, /* stats table */
.pg_authenticate = &lockd_authenticate /* export authentication */
};