/* $NetBSD: nlm_advlock.c,v 1.2 2016/12/13 21:58:17 pgoyette Exp $ */

/* $NetBSD: nlm_advlock.c,v 1.2 2016/12/13 21:58:17 pgoyette Exp $ */
/*-
* Copyright (c) 2008 Isilon Inc http://www.isilon.com/
* Authors: Doug Rabson <[email protected]>
* Developed with Red Inc: Alfred Perlstein <[email protected]>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#include <sys/cdefs.h>
/* __FBSDID("FreeBSD: head/sys/nlm/nlm_advlock.c 302216 2016-06-26 20:08:42Z kib "); */
__RCSID("$NetBSD: nlm_advlock.c,v 1.2 2016/12/13 21:58:17 pgoyette Exp $");

#include <sys/param.h>
#include <sys/fcntl.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/lockf.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <sys/unistd.h>
#include <sys/vnode.h>

#include <fs/nfs/common/nfsproto.h>
#include <fs/nfs/client/nfs.h>
#include <fs/nfs/client/nfsmount.h>

#include <fs/nfs/nlm/nlm_prot.h>
#include <fs/nfs/nlm/nlm.h>

/*
* We need to keep track of the svid values used for F_FLOCK locks.
*/
struct nlm_file_svid {
int ns_refs; /* thread count + 1 if active */
int ns_svid; /* on-the-wire SVID for this file */
struct ucred *ns_ucred; /* creds to use for lock recovery */
void *ns_id; /* local struct file pointer */
bool_t ns_active; /* TRUE if we own a lock */
LIST_ENTRY(nlm_file_svid) ns_link;
};
LIST_HEAD(nlm_file_svid_list, nlm_file_svid);

#define NLM_SVID_HASH_SIZE 256
struct nlm_file_svid_list nlm_file_svids[NLM_SVID_HASH_SIZE];

struct mtx nlm_svid_lock;
static struct unrhdr *nlm_svid_allocator;
static volatile u_int nlm_xid = 1;

static int nlm_setlock(struct nlm_host *host, struct rpc_callextra *ext,
rpcvers_t vers, struct timeval *timo, int retries,
struct vnode *vp, int op, struct flock *fl, int flags,
int svid, size_t fhlen, void *fh, off_t size, bool_t reclaim);
static int nlm_clearlock(struct nlm_host *host, struct rpc_callextra *ext,
rpcvers_t vers, struct timeval *timo, int retries,
struct vnode *vp, int op, struct flock *fl, int flags,
int svid, size_t fhlen, void *fh, off_t size);
static int nlm_getlock(struct nlm_host *host, struct rpc_callextra *ext,
rpcvers_t vers, struct timeval *timo, int retries,
struct vnode *vp, int op, struct flock *fl, int flags,
int svid, size_t fhlen, void *fh, off_t size);
static int nlm_map_status(nlm4_stats stat);
static struct nlm_file_svid *nlm_find_svid(void *id);
static void nlm_free_svid(struct nlm_file_svid *nf);
static int nlm_init_lock(struct flock *fl, int flags, int svid,
rpcvers_t vers, size_t fhlen, void *fh, off_t size,
struct nlm4_lock *lock, char oh_space[32]);

static void
nlm_client_init(void *dummy)
{
int i;

mtx_init(&nlm_svid_lock, "NLM svid lock", NULL, MTX_DEF);
/* pid_max cannot be greater than PID_MAX */
nlm_svid_allocator = new_unrhdr(PID_MAX + 2, INT_MAX, &nlm_svid_lock);
for (i = 0; i < NLM_SVID_HASH_SIZE; i++)
LIST_INIT(&nlm_file_svids[i]);
}
SYSINIT(nlm_client_init, SI_SUB_LOCK, SI_ORDER_FIRST, nlm_client_init, NULL);

static int
nlm_msg(struct thread *td, const char *server, const char *msg, int error)
{
struct proc *p;

p = td ? td->td_proc : NULL;
if (error) {
tprintf(p, LOG_INFO, "nfs server %s: %s, error %d\n", server,
msg, error);
} else {
tprintf(p, LOG_INFO, "nfs server %s: %s\n", server, msg);
}
return (0);
}

struct nlm_feedback_arg {
bool_t nf_printed;
struct nfsmount *nf_nmp;
};

static void
nlm_down(struct nlm_feedback_arg *nf, struct thread *td,
const char *msg, int error)
{
struct nfsmount *nmp = nf->nf_nmp;

if (nmp == NULL)
return;
mtx_lock(&nmp->nm_mtx);
if (!(nmp->nm_state & NFSSTA_LOCKTIMEO)) {
nmp->nm_state |= NFSSTA_LOCKTIMEO;
mtx_unlock(&nmp->nm_mtx);
vfs_event_signal(&nmp->nm_mountp->mnt_stat.f_fsid,
VQ_NOTRESPLOCK, 0);
} else {
mtx_unlock(&nmp->nm_mtx);
}

nf->nf_printed = TRUE;
nlm_msg(td, nmp->nm_mountp->mnt_stat.f_mntfromname, msg, error);
}

static void
nlm_up(struct nlm_feedback_arg *nf, struct thread *td,
const char *msg)
{
struct nfsmount *nmp = nf->nf_nmp;

if (!nf->nf_printed)
return;

nlm_msg(td, nmp->nm_mountp->mnt_stat.f_mntfromname, msg, 0);

mtx_lock(&nmp->nm_mtx);
if (nmp->nm_state & NFSSTA_LOCKTIMEO) {
nmp->nm_state &= ~NFSSTA_LOCKTIMEO;
mtx_unlock(&nmp->nm_mtx);
vfs_event_signal(&nmp->nm_mountp->mnt_stat.f_fsid,
VQ_NOTRESPLOCK, 1);
} else {
mtx_unlock(&nmp->nm_mtx);
}
}

static void
nlm_feedback(int type, int proc, void *arg)
{
struct thread *td = curthread;
struct nlm_feedback_arg *nf = (struct nlm_feedback_arg *) arg;

switch (type) {
case FEEDBACK_REXMIT2:
case FEEDBACK_RECONNECT:
nlm_down(nf, td, "lockd not responding", 0);
break;

case FEEDBACK_OK:
nlm_up(nf, td, "lockd is alive again");
break;
}
}

/*
* nlm_advlock --
* NFS advisory byte-level locks.
*/
static int
nlm_advlock_internal(struct vnode *vp, void *id, int op, struct flock *fl,
int flags, bool_t reclaim, bool_t unlock_vp)
{
struct thread *td = curthread;
struct nfsmount *nmp;
off_t size;
size_t fhlen;
union nfsfh fh;
struct sockaddr *sa;
struct sockaddr_storage ss;
char servername[MNAMELEN];
struct timeval timo;
int retries;
rpcvers_t vers;
struct nlm_host *host;
struct rpc_callextra ext;
struct nlm_feedback_arg nf;
AUTH *auth;
struct ucred *cred, *cred1;
struct nlm_file_svid *ns;
int svid;
int error;
int is_v3;

ASSERT_VOP_LOCKED(vp, "nlm_advlock_1");

nmp = VFSTONFS(vp->v_mount);
/*
* Push any pending writes to the server and flush our cache
* so that if we are contending with another machine for a
* file, we get whatever they wrote and vice-versa.
*/
if (op == F_SETLK || op == F_UNLCK)
nmp->nm_vinvalbuf(vp, V_SAVE, td, 1);

strcpy(servername, nmp->nm_hostname);
nmp->nm_getinfo(vp, fh.fh_bytes, &fhlen, &ss, &is_v3, &size, &timo);
sa = (struct sockaddr *) &ss;
if (is_v3 != 0)
vers = NLM_VERS4;
else
vers = NLM_VERS;

if (nmp->nm_flag & NFSMNT_SOFT)
retries = nmp->nm_retry;
else
retries = INT_MAX;

/*
* We need to switch to mount-point creds so that we can send
* packets from a privileged port. Reference mnt_cred and
* switch to them before unlocking the vnode, since mount
* point could be unmounted right after unlock.
*/
cred = td->td_ucred;
td->td_ucred = vp->v_mount->mnt_cred;
crhold(td->td_ucred);
if (unlock_vp)
VOP_UNLOCK(vp, 0);

host = nlm_find_host_by_name(servername, sa, vers);
auth = authunix_create(cred);
memset(&ext, 0, sizeof(ext));

nf.nf_printed = FALSE;
nf.nf_nmp = nmp;
ext.rc_auth = auth;

ext.rc_feedback = nlm_feedback;
ext.rc_feedback_arg = &nf;
ext.rc_timers = NULL;

ns = NULL;
if (flags & F_FLOCK) {
ns = nlm_find_svid(id);
KASSERT(fl->l_start == 0 && fl->l_len == 0,
("F_FLOCK lock requests must be whole-file locks"));
if (!ns->ns_ucred) {
/*
* Remember the creds used for locking in case
* we need to recover the lock later.
*/
ns->ns_ucred = crdup(cred);
}
svid = ns->ns_svid;
} else if (flags & F_REMOTE) {
/*
* If we are recovering after a server restart or
* trashing locks on a force unmount, use the same
* svid as last time.
*/
svid = fl->l_pid;
} else {
svid = ((struct proc *) id)->p_pid;
}

switch(op) {
case F_SETLK:
if ((flags & (F_FLOCK|F_WAIT)) == (F_FLOCK|F_WAIT)
&& fl->l_type == F_WRLCK) {
/*
* The semantics for flock(2) require that any
* shared lock on the file must be released
* before an exclusive lock is granted. The
* local locking code interprets this by
* unlocking the file before sleeping on a
* blocked exclusive lock request. We
* approximate this by first attempting
* non-blocking and if that fails, we unlock
* the file and block.
*/
error = nlm_setlock(host, &ext, vers, &timo, retries,
vp, F_SETLK, fl, flags & ~F_WAIT,
svid, fhlen, &fh.fh_bytes, size, reclaim);
if (error == EAGAIN) {
fl->l_type = F_UNLCK;
error = nlm_clearlock(host, &ext, vers, &timo,
retries, vp, F_UNLCK, fl, flags,
svid, fhlen, &fh.fh_bytes, size);
fl->l_type = F_WRLCK;
if (!error) {
mtx_lock(&nlm_svid_lock);
if (ns->ns_active) {
ns->ns_refs--;
ns->ns_active = FALSE;
}
mtx_unlock(&nlm_svid_lock);
flags |= F_WAIT;
error = nlm_setlock(host, &ext, vers,
&timo, retries, vp, F_SETLK, fl,
flags, svid, fhlen, &fh.fh_bytes,
size, reclaim);
}
}
} else {
error = nlm_setlock(host, &ext, vers, &timo, retries,
vp, op, fl, flags, svid, fhlen, &fh.fh_bytes,
size, reclaim);
}
if (!error && ns) {
mtx_lock(&nlm_svid_lock);
if (!ns->ns_active) {
/*
* Add one to the reference count to
* hold onto the SVID for the lifetime
* of the lock. Note that since
* F_FLOCK only supports whole-file
* locks, there can only be one active
* lock for this SVID.
*/
ns->ns_refs++;
ns->ns_active = TRUE;
}
mtx_unlock(&nlm_svid_lock);
}
break;

case F_UNLCK:
error = nlm_clearlock(host, &ext, vers, &timo, retries,
vp, op, fl, flags, svid, fhlen, &fh.fh_bytes, size);
if (!error && ns) {
mtx_lock(&nlm_svid_lock);
if (ns->ns_active) {
ns->ns_refs--;
ns->ns_active = FALSE;
}
mtx_unlock(&nlm_svid_lock);
}
break;

case F_GETLK:
error = nlm_getlock(host, &ext, vers, &timo, retries,
vp, op, fl, flags, svid, fhlen, &fh.fh_bytes, size);
break;

default:
error = EINVAL;
break;
}

if (ns)
nlm_free_svid(ns);

cred1 = td->td_ucred;
td->td_ucred = cred;
crfree(cred1);
AUTH_DESTROY(auth);

nlm_host_release(host);

return (error);
}

int
nlm_advlock(struct vop_advlock_args *ap)
{

return (nlm_advlock_internal(ap->a_vp, ap->a_id, ap->a_op, ap->a_fl,
ap->a_flags, FALSE, TRUE));
}

/*
* Set the creds of td to the creds of the given lock's owner. The new
* creds reference count will be incremented via crhold. The caller is
* responsible for calling crfree and restoring td's original creds.
*/
static void
nlm_set_creds_for_lock(struct thread *td, struct flock *fl)
{
int i;
struct nlm_file_svid *ns;
struct proc *p;
struct ucred *cred;

cred = NULL;
if (fl->l_pid > PID_MAX) {
/*
* If this was originally a F_FLOCK-style lock, we
* recorded the creds used when it was originally
* locked in the nlm_file_svid structure.
*/
mtx_lock(&nlm_svid_lock);
for (i = 0; i < NLM_SVID_HASH_SIZE; i++) {
for (ns = LIST_FIRST(&nlm_file_svids[i]); ns;
ns = LIST_NEXT(ns, ns_link)) {
if (ns->ns_svid == fl->l_pid) {
cred = crhold(ns->ns_ucred);
break;
}
}
}
mtx_unlock(&nlm_svid_lock);
} else {
/*
* This lock is owned by a process. Get a reference to
* the process creds.
*/
p = pfind(fl->l_pid);
if (p) {
cred = crhold(p->p_ucred);
PROC_UNLOCK(p);
}
}

/*
* If we can't find a cred, fall back on the recovery
* thread's cred.
*/
if (!cred) {
cred = crhold(td->td_ucred);
}

td->td_ucred = cred;
}

static int
nlm_reclaim_free_lock(struct vnode *vp, struct flock *fl, void *arg)
{
struct flock newfl;
struct thread *td = curthread;
struct ucred *oldcred;
int error;

newfl = *fl;
newfl.l_type = F_UNLCK;

oldcred = td->td_ucred;
nlm_set_creds_for_lock(td, &newfl);

error = nlm_advlock_internal(vp, NULL, F_UNLCK, &newfl, F_REMOTE,
FALSE, FALSE);

crfree(td->td_ucred);
td->td_ucred = oldcred;

return (error);
}

int
nlm_reclaim(struct vop_reclaim_args *ap)
{

nlm_cancel_wait(ap->a_vp);
lf_iteratelocks_vnode(ap->a_vp, nlm_reclaim_free_lock, NULL);
return (0);
}

struct nlm_recovery_context {
struct nlm_host *nr_host; /* host we are recovering */
int nr_state; /* remote NSM state for recovery */
};

static int
nlm_client_recover_lock(struct vnode *vp, struct flock *fl, void *arg)
{
struct nlm_recovery_context *nr = (struct nlm_recovery_context *) arg;
struct thread *td = curthread;
struct ucred *oldcred;
int state, error;

/*
* If the remote NSM state changes during recovery, the host
* must have rebooted a second time. In that case, we must
* restart the recovery.
*/
state = nlm_host_get_state(nr->nr_host);
if (nr->nr_state != state)
return (ERESTART);

error = vn_lock(vp, LK_SHARED);
if (error)
return (error);

oldcred = td->td_ucred;
nlm_set_creds_for_lock(td, fl);

error = nlm_advlock_internal(vp, NULL, F_SETLK, fl, F_REMOTE,
TRUE, TRUE);

crfree(td->td_ucred);
td->td_ucred = oldcred;

return (error);
}

void
nlm_client_recovery(struct nlm_host *host)
{
struct nlm_recovery_context nr;
int sysid, error;

sysid = NLM_SYSID_CLIENT | nlm_host_get_sysid(host);
do {
nr.nr_host = host;
nr.nr_state = nlm_host_get_state(host);
error = lf_iteratelocks_sysid(sysid,
nlm_client_recover_lock, &nr);
} while (error == ERESTART);
}

static void
nlm_convert_to_nlm_lock(struct nlm_lock *dst, struct nlm4_lock *src)
{

dst->caller_name = src->caller_name;
dst->fh = src->fh;
dst->oh = src->oh;
dst->svid = src->svid;
dst->l_offset = src->l_offset;
dst->l_len = src->l_len;
}

static void
nlm_convert_to_nlm4_holder(struct nlm4_holder *dst, struct nlm_holder *src)
{

dst->exclusive = src->exclusive;
dst->svid = src->svid;
dst->oh = src->oh;
dst->l_offset = src->l_offset;
dst->l_len = src->l_len;
}

static void
nlm_convert_to_nlm4_res(struct nlm4_res *dst, struct nlm_res *src)
{
dst->cookie = src->cookie;
dst->stat.stat = (enum nlm4_stats) src->stat.stat;
}

static enum clnt_stat
nlm_test_rpc(rpcvers_t vers, nlm4_testargs *args, nlm4_testres *res, CLIENT *client,
struct rpc_callextra *ext, struct timeval timo)
{
if (vers == NLM_VERS4) {
return nlm4_test_4(args, res, client, ext, timo);
} else {
nlm_testargs args1;
nlm_testres res1;
enum clnt_stat stat;

args1.cookie = args->cookie;
args1.exclusive = args->exclusive;
nlm_convert_to_nlm_lock(&args1.alock, &args->alock);
memset(&res1, 0, sizeof(res1));

stat = nlm_test_1(&args1, &res1, client, ext, timo);

if (stat == RPC_SUCCESS) {
res->cookie = res1.cookie;
res->stat.stat = (enum nlm4_stats) res1.stat.stat;
if (res1.stat.stat == nlm_denied)
nlm_convert_to_nlm4_holder(
&res->stat.nlm4_testrply_u.holder,
&res1.stat.nlm_testrply_u.holder);
}

return (stat);
}
}

static enum clnt_stat
nlm_lock_rpc(rpcvers_t vers, nlm4_lockargs *args, nlm4_res *res, CLIENT *client,
struct rpc_callextra *ext, struct timeval timo)
{
if (vers == NLM_VERS4) {
return nlm4_lock_4(args, res, client, ext, timo);
} else {
nlm_lockargs args1;
nlm_res res1;
enum clnt_stat stat;

args1.cookie = args->cookie;
args1.block = args->block;
args1.exclusive = args->exclusive;
nlm_convert_to_nlm_lock(&args1.alock, &args->alock);
args1.reclaim = args->reclaim;
args1.state = args->state;
memset(&res1, 0, sizeof(res1));

stat = nlm_lock_1(&args1, &res1, client, ext, timo);

if (stat == RPC_SUCCESS) {
nlm_convert_to_nlm4_res(res, &res1);
}

return (stat);
}
}

static enum clnt_stat
nlm_cancel_rpc(rpcvers_t vers, nlm4_cancargs *args, nlm4_res *res, CLIENT *client,
struct rpc_callextra *ext, struct timeval timo)
{
if (vers == NLM_VERS4) {
return nlm4_cancel_4(args, res, client, ext, timo);
} else {
nlm_cancargs args1;
nlm_res res1;
enum clnt_stat stat;

args1.cookie = args->cookie;
args1.block = args->block;
args1.exclusive = args->exclusive;
nlm_convert_to_nlm_lock(&args1.alock, &args->alock);
memset(&res1, 0, sizeof(res1));

stat = nlm_cancel_1(&args1, &res1, client, ext, timo);

if (stat == RPC_SUCCESS) {
nlm_convert_to_nlm4_res(res, &res1);
}

return (stat);
}
}

static enum clnt_stat
nlm_unlock_rpc(rpcvers_t vers, nlm4_unlockargs *args, nlm4_res *res, CLIENT *client,
struct rpc_callextra *ext, struct timeval timo)
{
if (vers == NLM_VERS4) {
return nlm4_unlock_4(args, res, client, ext, timo);
} else {
nlm_unlockargs args1;
nlm_res res1;
enum clnt_stat stat;

args1.cookie = args->cookie;
nlm_convert_to_nlm_lock(&args1.alock, &args->alock);
memset(&res1, 0, sizeof(res1));

stat = nlm_unlock_1(&args1, &res1, client, ext, timo);

if (stat == RPC_SUCCESS) {
nlm_convert_to_nlm4_res(res, &res1);
}

return (stat);
}
}

/*
* Called after a lock request (set or clear) succeeded. We record the
* details in the local lock manager. Note that since the remote
* server has granted the lock, we can be sure that it doesn't
* conflict with any other locks we have in the local lock manager.
*
* Since it is possible that host may also make NLM client requests to
* our NLM server, we use a different sysid value to record our own
* client locks.
*
* Note that since it is possible for us to receive replies from the
* server in a different order than the locks were granted (e.g. if
* many local threads are contending for the same lock), we must use a
* blocking operation when registering with the local lock manager.
* We expect that any actual wait will be rare and short hence we
* ignore signals for this.
*/
static void
nlm_record_lock(struct vnode *vp, int op, struct flock *fl,
int svid, int sysid, off_t size)
{
struct vop_advlockasync_args a;
struct flock newfl;
struct proc *p;
int error, stops_deferred;

a.a_vp = vp;
a.a_id = NULL;
a.a_op = op;
a.a_fl = &newfl;
a.a_flags = F_REMOTE|F_WAIT|F_NOINTR;
a.a_task = NULL;
a.a_cookiep = NULL;
newfl.l_start = fl->l_start;
newfl.l_len = fl->l_len;
newfl.l_type = fl->l_type;
newfl.l_whence = fl->l_whence;
newfl.l_pid = svid;
newfl.l_sysid = NLM_SYSID_CLIENT | sysid;

for (;;) {
error = lf_advlockasync(&a, &vp->v_lockf, size);
if (error == EDEADLK) {
/*
* Locks are associated with the processes and
* not with threads. Suppose we have two
* threads A1 A2 in one process, A1 locked
* file f1, A2 is locking file f2, and A1 is
* unlocking f1. Then remote server may
* already unlocked f1, while local still not
* yet scheduled A1 to make the call to local
* advlock manager. The process B owns lock on
* f2 and issued the lock on f1. Remote would
* grant B the request on f1, but local would
* return EDEADLK.
*/
pause("nlmdlk", 1);
p = curproc;
stops_deferred = sigdeferstop(SIGDEFERSTOP_OFF);
PROC_LOCK(p);
thread_suspend_check(0);
PROC_UNLOCK(p);
sigallowstop(stops_deferred);
} else if (error == EINTR) {
/*
* lf_purgelocks() might wake up the lock
* waiter and removed our lock graph edges.
* There is no sense in re-trying recording
* the lock to the local manager after
* reclaim.
*/
error = 0;
break;
} else
break;
}
KASSERT(error == 0 || error == ENOENT,
("Failed to register NFS lock locally - error=%d", error));
}

static int
nlm_setlock(struct nlm_host *host, struct rpc_callextra *ext,
rpcvers_t vers, struct timeval *timo, int retries,
struct vnode *vp, int op, struct flock *fl, int flags,
int svid, size_t fhlen, void *fh, off_t size, bool_t reclaim)
{
struct nlm4_lockargs args;
char oh_space[32];
struct nlm4_res res;
u_int xid;
CLIENT *client;
enum clnt_stat stat;
int retry, block, exclusive;
void *wait_handle = NULL;
int error;

memset(&args, 0, sizeof(args));
memset(&res, 0, sizeof(res));

block = (flags & F_WAIT) ? TRUE : FALSE;
exclusive = (fl->l_type == F_WRLCK);

error = nlm_init_lock(fl, flags, svid, vers, fhlen, fh, size,
&args.alock, oh_space);
if (error)
return (error);
args.block = block;
args.exclusive = exclusive;
args.reclaim = reclaim;
args.state = nlm_nsm_state;

retry = 5*hz;
for (;;) {
client = nlm_host_get_rpc(host, FALSE);
if (!client)
return (ENOLCK); /* XXX retry? */

if (block)
wait_handle = nlm_register_wait_lock(&args.alock, vp);

xid = atomic_fetchadd_int(&nlm_xid, 1);
args.cookie.n_len = sizeof(xid);
args.cookie.n_bytes = (char*) &xid;

stat = nlm_lock_rpc(vers, &args, &res, client, ext, *timo);

CLNT_RELEASE(client);

if (stat != RPC_SUCCESS) {
if (block)
nlm_deregister_wait_lock(wait_handle);
if (retries) {
retries--;
continue;
}
return (EINVAL);
}

/*
* Free res.cookie.
*/
xdr_free((xdrproc_t) xdr_nlm4_res, &res);

if (block && res.stat.stat != nlm4_blocked)
nlm_deregister_wait_lock(wait_handle);

if (res.stat.stat == nlm4_denied_grace_period) {
/*
* The server has recently rebooted and is
* giving old clients a change to reclaim
* their locks. Wait for a few seconds and try
* again.
*/
error = tsleep(&args, PCATCH, "nlmgrace", retry);
if (error && error != EWOULDBLOCK)
return (error);
retry = 2*retry;
if (retry > 30*hz)
retry = 30*hz;
continue;
}

if (block && res.stat.stat == nlm4_blocked) {
/*
* The server should call us back with a
* granted message when the lock succeeds. In
* order to deal with broken servers, lost
* granted messages and server reboots, we
* will also re-try every few seconds.
*/
error = nlm_wait_lock(wait_handle, retry);
if (error == EWOULDBLOCK) {
retry = 2*retry;
if (retry > 30*hz)
retry = 30*hz;
continue;
}
if (error) {
/*
* We need to call the server to
* cancel our lock request.
*/
nlm4_cancargs cancel;

memset(&cancel, 0, sizeof(cancel));

xid = atomic_fetchadd_int(&nlm_xid, 1);
cancel.cookie.n_len = sizeof(xid);
cancel.cookie.n_bytes = (char*) &xid;
cancel.block = block;
cancel.exclusive = exclusive;
cancel.alock = args.alock;

do {
client = nlm_host_get_rpc(host, FALSE);
if (!client)
/* XXX retry? */
return (ENOLCK);

stat = nlm_cancel_rpc(vers, &cancel,
&res, client, ext, *timo);

CLNT_RELEASE(client);

if (stat != RPC_SUCCESS) {
/*
* We need to cope
* with temporary
* network partitions
* as well as server
* reboots. This means
* we have to keep
* trying to cancel
* until the server
* wakes up again.
*/
pause("nlmcancel", 10*hz);
}
} while (stat != RPC_SUCCESS);

/*
* Free res.cookie.
*/
xdr_free((xdrproc_t) xdr_nlm4_res, &res);

switch (res.stat.stat) {
case nlm_denied:
/*
* There was nothing
* to cancel. We are
* going to go ahead
* and assume we got
* the lock.
*/
error = 0;
break;

case nlm4_denied_grace_period:
/*
* The server has
* recently rebooted -
* treat this as a
* successful
* cancellation.
*/
break;

case nlm4_granted:
/*
* We managed to
* cancel.
*/
break;

default:
/*
* Broken server
* implementation -
* can't really do
* anything here.
*/
break;
}

}
} else {
error = nlm_map_status(res.stat.stat);
}

if (!error && !reclaim) {
nlm_record_lock(vp, op, fl, args.alock.svid,
nlm_host_get_sysid(host), size);
nlm_host_monitor(host, 0);
}

return (error);
}
}

static int
nlm_clearlock(struct nlm_host *host, struct rpc_callextra *ext,
rpcvers_t vers, struct timeval *timo, int retries,
struct vnode *vp, int op, struct flock *fl, int flags,
int svid, size_t fhlen, void *fh, off_t size)
{
struct nlm4_unlockargs args;
char oh_space[32];
struct nlm4_res res;
u_int xid;
CLIENT *client;
enum clnt_stat stat;
int error;

memset(&args, 0, sizeof(args));
memset(&res, 0, sizeof(res));

error = nlm_init_lock(fl, flags, svid, vers, fhlen, fh, size,
&args.alock, oh_space);
if (error)
return (error);

for (;;) {
client = nlm_host_get_rpc(host, FALSE);
if (!client)
return (ENOLCK); /* XXX retry? */

xid = atomic_fetchadd_int(&nlm_xid, 1);
args.cookie.n_len = sizeof(xid);
args.cookie.n_bytes = (char*) &xid;

stat = nlm_unlock_rpc(vers, &args, &res, client, ext, *timo);

CLNT_RELEASE(client);

if (stat != RPC_SUCCESS) {
if (retries) {
retries--;
continue;
}
return (EINVAL);
}

/*
* Free res.cookie.
*/
xdr_free((xdrproc_t) xdr_nlm4_res, &res);

if (res.stat.stat == nlm4_denied_grace_period) {
/*
* The server has recently rebooted and is
* giving old clients a change to reclaim
* their locks. Wait for a few seconds and try
* again.
*/
error = tsleep(&args, PCATCH, "nlmgrace", 5*hz);
if (error && error != EWOULDBLOCK)
return (error);
continue;
}

/*
* If we are being called via nlm_reclaim (which will
* use the F_REMOTE flag), don't record the lock
* operation in the local lock manager since the vnode
* is going away.
*/
if (!(flags & F_REMOTE))
nlm_record_lock(vp, op, fl, args.alock.svid,
nlm_host_get_sysid(host), size);

return (0);
}
}

static int
nlm_getlock(struct nlm_host *host, struct rpc_callextra *ext,
rpcvers_t vers, struct timeval *timo, int retries,
struct vnode *vp, int op, struct flock *fl, int flags,
int svid, size_t fhlen, void *fh, off_t size)
{
struct nlm4_testargs args;
char oh_space[32];
struct nlm4_testres res;
u_int xid;
CLIENT *client;
enum clnt_stat stat;
int exclusive;
int error;

KASSERT(!(flags & F_FLOCK), ("unexpected F_FLOCK for F_GETLK"));

memset(&args, 0, sizeof(args));
memset(&res, 0, sizeof(res));

exclusive = (fl->l_type == F_WRLCK);

error = nlm_init_lock(fl, flags, svid, vers, fhlen, fh, size,
&args.alock, oh_space);
if (error)
return (error);
args.exclusive = exclusive;

for (;;) {
client = nlm_host_get_rpc(host, FALSE);
if (!client)
return (ENOLCK); /* XXX retry? */

xid = atomic_fetchadd_int(&nlm_xid, 1);
args.cookie.n_len = sizeof(xid);
args.cookie.n_bytes = (char*) &xid;

stat = nlm_test_rpc(vers, &args, &res, client, ext, *timo);

CLNT_RELEASE(client);

if (stat != RPC_SUCCESS) {
if (retries) {
retries--;
continue;
}
return (EINVAL);
}

if (res.stat.stat == nlm4_denied_grace_period) {
/*
* The server has recently rebooted and is
* giving old clients a change to reclaim
* their locks. Wait for a few seconds and try
* again.
*/
xdr_free((xdrproc_t) xdr_nlm4_testres, &res);
error = tsleep(&args, PCATCH, "nlmgrace", 5*hz);
if (error && error != EWOULDBLOCK)
return (error);
continue;
}

if (res.stat.stat == nlm4_denied) {
struct nlm4_holder *h =
&res.stat.nlm4_testrply_u.holder;
fl->l_start = h->l_offset;
fl->l_len = h->l_len;
fl->l_pid = h->svid;
if (h->exclusive)
fl->l_type = F_WRLCK;
else
fl->l_type = F_RDLCK;
fl->l_whence = SEEK_SET;
fl->l_sysid = 0;
} else {
fl->l_type = F_UNLCK;
}

xdr_free((xdrproc_t) xdr_nlm4_testres, &res);

return (0);
}
}

static int
nlm_map_status(nlm4_stats stat)
{
switch (stat) {
case nlm4_granted:
return (0);

case nlm4_denied:
return (EAGAIN);

case nlm4_denied_nolocks:
return (ENOLCK);

case nlm4_deadlck:
return (EDEADLK);

case nlm4_rofs:
return (EROFS);

case nlm4_stale_fh:
return (ESTALE);

case nlm4_fbig:
return (EFBIG);

case nlm4_failed:
return (EACCES);

default:
return (EINVAL);
}
}

static struct nlm_file_svid *
nlm_find_svid(void *id)
{
struct nlm_file_svid *ns, *newns;
int h;

h = (((uintptr_t) id) >> 7) % NLM_SVID_HASH_SIZE;

mtx_lock(&nlm_svid_lock);
LIST_FOREACH(ns, &nlm_file_svids[h], ns_link) {
if (ns->ns_id == id) {
ns->ns_refs++;
break;
}
}
mtx_unlock(&nlm_svid_lock);
if (!ns) {
int svid = alloc_unr(nlm_svid_allocator);
newns = malloc(sizeof(struct nlm_file_svid), M_NLM,
M_WAITOK);
newns->ns_refs = 1;
newns->ns_id = id;
newns->ns_svid = svid;
newns->ns_ucred = NULL;
newns->ns_active = FALSE;

/*
* We need to check for a race with some other
* thread allocating a svid for this file.
*/
mtx_lock(&nlm_svid_lock);
LIST_FOREACH(ns, &nlm_file_svids[h], ns_link) {
if (ns->ns_id == id) {
ns->ns_refs++;
break;
}
}
if (ns) {
mtx_unlock(&nlm_svid_lock);
free_unr(nlm_svid_allocator, newns->ns_svid);
free(newns, M_NLM);
} else {
LIST_INSERT_HEAD(&nlm_file_svids[h], newns,
ns_link);
ns = newns;
mtx_unlock(&nlm_svid_lock);
}
}

return (ns);
}

static void
nlm_free_svid(struct nlm_file_svid *ns)
{

mtx_lock(&nlm_svid_lock);
ns->ns_refs--;
if (!ns->ns_refs) {
KASSERT(!ns->ns_active, ("Freeing active SVID"));
LIST_REMOVE(ns, ns_link);
mtx_unlock(&nlm_svid_lock);
free_unr(nlm_svid_allocator, ns->ns_svid);
if (ns->ns_ucred)
crfree(ns->ns_ucred);
free(ns, M_NLM);
} else {
mtx_unlock(&nlm_svid_lock);
}
}

static int
nlm_init_lock(struct flock *fl, int flags, int svid,
rpcvers_t vers, size_t fhlen, void *fh, off_t size,
struct nlm4_lock *lock, char oh_space[32])
{
size_t oh_len;
off_t start, len;

if (fl->l_whence == SEEK_END) {
if (size > OFF_MAX
|| (fl->l_start > 0 && size > OFF_MAX - fl->l_start))
return (EOVERFLOW);
start = size + fl->l_start;
} else if (fl->l_whence == SEEK_SET || fl->l_whence == SEEK_CUR) {
start = fl->l_start;
} else {
return (EINVAL);
}
if (start < 0)
return (EINVAL);
if (fl->l_len < 0) {
len = -fl->l_len;
start -= len;
if (start < 0)
return (EINVAL);
} else {
len = fl->l_len;
}

if (vers == NLM_VERS) {
/*
* Enforce range limits on V1 locks
*/
if (start > 0xffffffffLL || len > 0xffffffffLL)
return (EOVERFLOW);
}

snprintf(oh_space, 32, "%d@", svid);
oh_len = strlen(oh_space);
getcredhostname(NULL, oh_space + oh_len, 32 - oh_len);
oh_len = strlen(oh_space);

memset(lock, 0, sizeof(*lock));
lock->caller_name = prison0.pr_hostname;
lock->fh.n_len = fhlen;
lock->fh.n_bytes = fh;
lock->oh.n_len = oh_len;
lock->oh.n_bytes = oh_space;
lock->svid = svid;
lock->l_offset = start;
lock->l_len = len;

return (0);
}