linux/fs/lockd/clntproc.c
Chuck Lever 6c9dc42551 lockd: Update NSM state from SM_MON replies
When rpc.statd starts up in user space at boot time, it attempts to
write the latest NSM local state number into
/proc/sys/fs/nfs/nsm_local_state.

If lockd.ko isn't loaded yet (as is the case in most configurations),
that file doesn't exist, thus the kernel's NSM state remains set to
its initial value of zero during lockd operation.

This is a problem because rpc.statd and lockd use the NSM state number
to prevent repeated lock recovery on rebooted hosts.  If lockd sends
a zero NSM state, but then a delayed SM_NOTIFY with a real NSM state
number is received, there is no way for lockd or rpc.statd to
distinguish that stale SM_NOTIFY from an actual reboot.  Thus lock
recovery could be performed after the rebooted host has already
started reclaiming locks, and those locks will be lost.

We could change /etc/init.d/nfslock so it always modprobes lockd.ko
before starting rpc.statd.  However, if lockd.ko is ever unloaded
and reloaded, we are back at square one, since the NSM state is not
preserved across an unload/reload cycle.  This may happen frequently
on clients that use automounter.  A period of NFS inactivity causes
lockd.ko to be unloaded, and the kernel loses its NSM state setting.

Instead, let's use the fact that rpc.statd plants the local system's
NSM state in every SM_MON (and SM_UNMON) reply.  lockd performs a
synchronous SM_MON upcall to the local rpc.statd _before_ sending its
first NLM request to a new remote.  This would permit rpc.statd to
provide the current NSM state to lockd, even after lockd.ko had been
unloaded and reloaded.

Note that NLMPROC_LOCK arguments are constructed before the
nsm_monitor() call, so we have to rearrange argument construction very
slightly to make this all work out.

And, the kernel appears to treat NSM state as a u32 (see struct
nlm_args and nsm_res).  Make nsm_local_state a u32 as well, to ensure
we don't get bogus comparison results.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2009-06-17 18:02:10 -07:00

846 lines
21 KiB
C

/*
* linux/fs/lockd/clntproc.c
*
* RPC procedures for the client side NLM implementation
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/nfs_fs.h>
#include <linux/utsname.h>
#include <linux/freezer.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svc.h>
#include <linux/lockd/lockd.h>
#define NLMDBG_FACILITY NLMDBG_CLIENT
#define NLMCLNT_GRACE_WAIT (5*HZ)
#define NLMCLNT_POLL_TIMEOUT (30*HZ)
#define NLMCLNT_MAX_RETRIES 3
static int nlmclnt_test(struct nlm_rqst *, struct file_lock *);
static int nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
static int nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
static int nlm_stat_to_errno(__be32 stat);
static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
static int nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
static const struct rpc_call_ops nlmclnt_unlock_ops;
static const struct rpc_call_ops nlmclnt_cancel_ops;
/*
* Cookie counter for NLM requests
*/
static atomic_t nlm_cookie = ATOMIC_INIT(0x1234);
void nlmclnt_next_cookie(struct nlm_cookie *c)
{
u32 cookie = atomic_inc_return(&nlm_cookie);
memcpy(c->data, &cookie, 4);
c->len=4;
}
static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
{
atomic_inc(&lockowner->count);
return lockowner;
}
static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
{
if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
return;
list_del(&lockowner->list);
spin_unlock(&lockowner->host->h_lock);
nlm_release_host(lockowner->host);
kfree(lockowner);
}
static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
{
struct nlm_lockowner *lockowner;
list_for_each_entry(lockowner, &host->h_lockowners, list) {
if (lockowner->pid == pid)
return -EBUSY;
}
return 0;
}
static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
{
uint32_t res;
do {
res = host->h_pidcount++;
} while (nlm_pidbusy(host, res) < 0);
return res;
}
static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
{
struct nlm_lockowner *lockowner;
list_for_each_entry(lockowner, &host->h_lockowners, list) {
if (lockowner->owner != owner)
continue;
return nlm_get_lockowner(lockowner);
}
return NULL;
}
static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
{
struct nlm_lockowner *res, *new = NULL;
spin_lock(&host->h_lock);
res = __nlm_find_lockowner(host, owner);
if (res == NULL) {
spin_unlock(&host->h_lock);
new = kmalloc(sizeof(*new), GFP_KERNEL);
spin_lock(&host->h_lock);
res = __nlm_find_lockowner(host, owner);
if (res == NULL && new != NULL) {
res = new;
atomic_set(&new->count, 1);
new->owner = owner;
new->pid = __nlm_alloc_pid(host);
new->host = nlm_get_host(host);
list_add(&new->list, &host->h_lockowners);
new = NULL;
}
}
spin_unlock(&host->h_lock);
kfree(new);
return res;
}
/*
* Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
*/
static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
{
struct nlm_args *argp = &req->a_args;
struct nlm_lock *lock = &argp->lock;
nlmclnt_next_cookie(&argp->cookie);
memcpy(&lock->fh, NFS_FH(fl->fl_file->f_path.dentry->d_inode), sizeof(struct nfs_fh));
lock->caller = utsname()->nodename;
lock->oh.data = req->a_owner;
lock->oh.len = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
(unsigned int)fl->fl_u.nfs_fl.owner->pid,
utsname()->nodename);
lock->svid = fl->fl_u.nfs_fl.owner->pid;
lock->fl.fl_start = fl->fl_start;
lock->fl.fl_end = fl->fl_end;
lock->fl.fl_type = fl->fl_type;
}
static void nlmclnt_release_lockargs(struct nlm_rqst *req)
{
BUG_ON(req->a_args.lock.fl.fl_ops != NULL);
}
/**
* nlmclnt_proc - Perform a single client-side lock request
* @host: address of a valid nlm_host context representing the NLM server
* @cmd: fcntl-style file lock operation to perform
* @fl: address of arguments for the lock operation
*
*/
int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl)
{
struct nlm_rqst *call;
int status;
nlm_get_host(host);
call = nlm_alloc_call(host);
if (call == NULL)
return -ENOMEM;
nlmclnt_locks_init_private(fl, host);
/* Set up the argument struct */
nlmclnt_setlockargs(call, fl);
lock_kernel();
if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
if (fl->fl_type != F_UNLCK) {
call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
status = nlmclnt_lock(call, fl);
} else
status = nlmclnt_unlock(call, fl);
} else if (IS_GETLK(cmd))
status = nlmclnt_test(call, fl);
else
status = -EINVAL;
fl->fl_ops->fl_release_private(fl);
fl->fl_ops = NULL;
unlock_kernel();
dprintk("lockd: clnt proc returns %d\n", status);
return status;
}
EXPORT_SYMBOL_GPL(nlmclnt_proc);
/*
* Allocate an NLM RPC call struct
*
* Note: the caller must hold a reference to host. In case of failure,
* this reference will be released.
*/
struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
{
struct nlm_rqst *call;
for(;;) {
call = kzalloc(sizeof(*call), GFP_KERNEL);
if (call != NULL) {
atomic_set(&call->a_count, 1);
locks_init_lock(&call->a_args.lock.fl);
locks_init_lock(&call->a_res.lock.fl);
call->a_host = host;
return call;
}
if (signalled())
break;
printk("nlm_alloc_call: failed, waiting for memory\n");
schedule_timeout_interruptible(5*HZ);
}
nlm_release_host(host);
return NULL;
}
void nlm_release_call(struct nlm_rqst *call)
{
if (!atomic_dec_and_test(&call->a_count))
return;
nlm_release_host(call->a_host);
nlmclnt_release_lockargs(call);
kfree(call);
}
static void nlmclnt_rpc_release(void *data)
{
lock_kernel();
nlm_release_call(data);
unlock_kernel();
}
static int nlm_wait_on_grace(wait_queue_head_t *queue)
{
DEFINE_WAIT(wait);
int status = -EINTR;
prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
if (!signalled ()) {
schedule_timeout(NLMCLNT_GRACE_WAIT);
try_to_freeze();
if (!signalled ())
status = 0;
}
finish_wait(queue, &wait);
return status;
}
/*
* Generic NLM call
*/
static int
nlmclnt_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc)
{
struct nlm_host *host = req->a_host;
struct rpc_clnt *clnt;
struct nlm_args *argp = &req->a_args;
struct nlm_res *resp = &req->a_res;
struct rpc_message msg = {
.rpc_argp = argp,
.rpc_resp = resp,
.rpc_cred = cred,
};
int status;
dprintk("lockd: call procedure %d on %s\n",
(int)proc, host->h_name);
do {
if (host->h_reclaiming && !argp->reclaim)
goto in_grace_period;
/* If we have no RPC client yet, create one. */
if ((clnt = nlm_bind_host(host)) == NULL)
return -ENOLCK;
msg.rpc_proc = &clnt->cl_procinfo[proc];
/* Perform the RPC call. If an error occurs, try again */
if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
dprintk("lockd: rpc_call returned error %d\n", -status);
switch (status) {
case -EPROTONOSUPPORT:
status = -EINVAL;
break;
case -ECONNREFUSED:
case -ETIMEDOUT:
case -ENOTCONN:
nlm_rebind_host(host);
status = -EAGAIN;
break;
case -ERESTARTSYS:
return signalled () ? -EINTR : status;
default:
break;
}
break;
} else
if (resp->status == nlm_lck_denied_grace_period) {
dprintk("lockd: server in grace period\n");
if (argp->reclaim) {
printk(KERN_WARNING
"lockd: spurious grace period reject?!\n");
return -ENOLCK;
}
} else {
if (!argp->reclaim) {
/* We appear to be out of the grace period */
wake_up_all(&host->h_gracewait);
}
dprintk("lockd: server returns status %d\n", resp->status);
return 0; /* Okay, call complete */
}
in_grace_period:
/*
* The server has rebooted and appears to be in the grace
* period during which locks are only allowed to be
* reclaimed.
* We can only back off and try again later.
*/
status = nlm_wait_on_grace(&host->h_gracewait);
} while (status == 0);
return status;
}
/*
* Generic NLM call, async version.
*/
static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
{
struct nlm_host *host = req->a_host;
struct rpc_clnt *clnt;
struct rpc_task_setup task_setup_data = {
.rpc_message = msg,
.callback_ops = tk_ops,
.callback_data = req,
.flags = RPC_TASK_ASYNC,
};
dprintk("lockd: call procedure %d on %s (async)\n",
(int)proc, host->h_name);
/* If we have no RPC client yet, create one. */
clnt = nlm_bind_host(host);
if (clnt == NULL)
goto out_err;
msg->rpc_proc = &clnt->cl_procinfo[proc];
task_setup_data.rpc_client = clnt;
/* bootstrap and kick off the async RPC call */
return rpc_run_task(&task_setup_data);
out_err:
tk_ops->rpc_release(req);
return ERR_PTR(-ENOLCK);
}
static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
{
struct rpc_task *task;
task = __nlm_async_call(req, proc, msg, tk_ops);
if (IS_ERR(task))
return PTR_ERR(task);
rpc_put_task(task);
return 0;
}
/*
* NLM asynchronous call.
*/
int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
{
struct rpc_message msg = {
.rpc_argp = &req->a_args,
.rpc_resp = &req->a_res,
};
return nlm_do_async_call(req, proc, &msg, tk_ops);
}
int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
{
struct rpc_message msg = {
.rpc_argp = &req->a_res,
};
return nlm_do_async_call(req, proc, &msg, tk_ops);
}
/*
* NLM client asynchronous call.
*
* Note that although the calls are asynchronous, and are therefore
* guaranteed to complete, we still always attempt to wait for
* completion in order to be able to correctly track the lock
* state.
*/
static int nlmclnt_async_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
{
struct rpc_message msg = {
.rpc_argp = &req->a_args,
.rpc_resp = &req->a_res,
.rpc_cred = cred,
};
struct rpc_task *task;
int err;
task = __nlm_async_call(req, proc, &msg, tk_ops);
if (IS_ERR(task))
return PTR_ERR(task);
err = rpc_wait_for_completion_task(task);
rpc_put_task(task);
return err;
}
/*
* TEST for the presence of a conflicting lock
*/
static int
nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
{
int status;
status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_TEST);
if (status < 0)
goto out;
switch (req->a_res.status) {
case nlm_granted:
fl->fl_type = F_UNLCK;
break;
case nlm_lck_denied:
/*
* Report the conflicting lock back to the application.
*/
fl->fl_start = req->a_res.lock.fl.fl_start;
fl->fl_end = req->a_res.lock.fl.fl_end;
fl->fl_type = req->a_res.lock.fl.fl_type;
fl->fl_pid = 0;
break;
default:
status = nlm_stat_to_errno(req->a_res.status);
}
out:
nlm_release_call(req);
return status;
}
static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
{
new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
}
static void nlmclnt_locks_release_private(struct file_lock *fl)
{
list_del(&fl->fl_u.nfs_fl.list);
nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
}
static struct file_lock_operations nlmclnt_lock_ops = {
.fl_copy_lock = nlmclnt_locks_copy_lock,
.fl_release_private = nlmclnt_locks_release_private,
};
static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
{
BUG_ON(fl->fl_ops != NULL);
fl->fl_u.nfs_fl.state = 0;
fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
fl->fl_ops = &nlmclnt_lock_ops;
}
static int do_vfs_lock(struct file_lock *fl)
{
int res = 0;
switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
case FL_POSIX:
res = posix_lock_file_wait(fl->fl_file, fl);
break;
case FL_FLOCK:
res = flock_lock_file_wait(fl->fl_file, fl);
break;
default:
BUG();
}
return res;
}
/*
* LOCK: Try to create a lock
*
* Programmer Harassment Alert
*
* When given a blocking lock request in a sync RPC call, the HPUX lockd
* will faithfully return LCK_BLOCKED but never cares to notify us when
* the lock could be granted. This way, our local process could hang
* around forever waiting for the callback.
*
* Solution A: Implement busy-waiting
* Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
*
* For now I am implementing solution A, because I hate the idea of
* re-implementing lockd for a third time in two months. The async
* calls shouldn't be too hard to do, however.
*
* This is one of the lovely things about standards in the NFS area:
* they're so soft and squishy you can't really blame HP for doing this.
*/
static int
nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
{
struct rpc_cred *cred = nfs_file_cred(fl->fl_file);
struct nlm_host *host = req->a_host;
struct nlm_res *resp = &req->a_res;
struct nlm_wait *block = NULL;
unsigned char fl_flags = fl->fl_flags;
unsigned char fl_type;
int status = -ENOLCK;
if (nsm_monitor(host) < 0)
goto out;
req->a_args.state = nsm_local_state;
fl->fl_flags |= FL_ACCESS;
status = do_vfs_lock(fl);
fl->fl_flags = fl_flags;
if (status < 0)
goto out;
block = nlmclnt_prepare_block(host, fl);
again:
/*
* Initialise resp->status to a valid non-zero value,
* since 0 == nlm_lck_granted
*/
resp->status = nlm_lck_blocked;
for(;;) {
/* Reboot protection */
fl->fl_u.nfs_fl.state = host->h_state;
status = nlmclnt_call(cred, req, NLMPROC_LOCK);
if (status < 0)
break;
/* Did a reclaimer thread notify us of a server reboot? */
if (resp->status == nlm_lck_denied_grace_period)
continue;
if (resp->status != nlm_lck_blocked)
break;
/* Wait on an NLM blocking lock */
status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
if (status < 0)
break;
if (resp->status != nlm_lck_blocked)
break;
}
/* if we were interrupted while blocking, then cancel the lock request
* and exit
*/
if (resp->status == nlm_lck_blocked) {
if (!req->a_args.block)
goto out_unlock;
if (nlmclnt_cancel(host, req->a_args.block, fl) == 0)
goto out_unblock;
}
if (resp->status == nlm_granted) {
down_read(&host->h_rwsem);
/* Check whether or not the server has rebooted */
if (fl->fl_u.nfs_fl.state != host->h_state) {
up_read(&host->h_rwsem);
goto again;
}
/* Ensure the resulting lock will get added to granted list */
fl->fl_flags |= FL_SLEEP;
if (do_vfs_lock(fl) < 0)
printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__);
up_read(&host->h_rwsem);
fl->fl_flags = fl_flags;
status = 0;
}
if (status < 0)
goto out_unlock;
/*
* EAGAIN doesn't make sense for sleeping locks, and in some
* cases NLM_LCK_DENIED is returned for a permanent error. So
* turn it into an ENOLCK.
*/
if (resp->status == nlm_lck_denied && (fl_flags & FL_SLEEP))
status = -ENOLCK;
else
status = nlm_stat_to_errno(resp->status);
out_unblock:
nlmclnt_finish_block(block);
out:
nlm_release_call(req);
return status;
out_unlock:
/* Fatal error: ensure that we remove the lock altogether */
dprintk("lockd: lock attempt ended in fatal error.\n"
" Attempting to unlock.\n");
nlmclnt_finish_block(block);
fl_type = fl->fl_type;
fl->fl_type = F_UNLCK;
down_read(&host->h_rwsem);
do_vfs_lock(fl);
up_read(&host->h_rwsem);
fl->fl_type = fl_type;
fl->fl_flags = fl_flags;
nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
return status;
}
/*
* RECLAIM: Try to reclaim a lock
*/
int
nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl)
{
struct nlm_rqst reqst, *req;
int status;
req = &reqst;
memset(req, 0, sizeof(*req));
locks_init_lock(&req->a_args.lock.fl);
locks_init_lock(&req->a_res.lock.fl);
req->a_host = host;
req->a_flags = 0;
/* Set up the argument struct */
nlmclnt_setlockargs(req, fl);
req->a_args.reclaim = 1;
status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_LOCK);
if (status >= 0 && req->a_res.status == nlm_granted)
return 0;
printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
"(errno %d, status %d)\n", fl->fl_pid,
status, ntohl(req->a_res.status));
/*
* FIXME: This is a serious failure. We can
*
* a. Ignore the problem
* b. Send the owning process some signal (Linux doesn't have
* SIGLOST, though...)
* c. Retry the operation
*
* Until someone comes up with a simple implementation
* for b or c, I'll choose option a.
*/
return -ENOLCK;
}
/*
* UNLOCK: remove an existing lock
*/
static int
nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
{
struct nlm_host *host = req->a_host;
struct nlm_res *resp = &req->a_res;
int status;
unsigned char fl_flags = fl->fl_flags;
/*
* Note: the server is supposed to either grant us the unlock
* request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
* case, we want to unlock.
*/
fl->fl_flags |= FL_EXISTS;
down_read(&host->h_rwsem);
status = do_vfs_lock(fl);
up_read(&host->h_rwsem);
fl->fl_flags = fl_flags;
if (status == -ENOENT) {
status = 0;
goto out;
}
atomic_inc(&req->a_count);
status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
if (status < 0)
goto out;
if (resp->status == nlm_granted)
goto out;
if (resp->status != nlm_lck_denied_nolocks)
printk("lockd: unexpected unlock status: %d\n", resp->status);
/* What to do now? I'm out of my depth... */
status = -ENOLCK;
out:
nlm_release_call(req);
return status;
}
static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
{
struct nlm_rqst *req = data;
u32 status = ntohl(req->a_res.status);
if (RPC_ASSASSINATED(task))
goto die;
if (task->tk_status < 0) {
dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
goto retry_rebind;
}
if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
rpc_delay(task, NLMCLNT_GRACE_WAIT);
goto retry_unlock;
}
if (status != NLM_LCK_GRANTED)
printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
die:
return;
retry_rebind:
lock_kernel();
nlm_rebind_host(req->a_host);
unlock_kernel();
retry_unlock:
rpc_restart_call(task);
}
static const struct rpc_call_ops nlmclnt_unlock_ops = {
.rpc_call_done = nlmclnt_unlock_callback,
.rpc_release = nlmclnt_rpc_release,
};
/*
* Cancel a blocked lock request.
* We always use an async RPC call for this in order not to hang a
* process that has been Ctrl-C'ed.
*/
static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
{
struct nlm_rqst *req;
int status;
dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
" Attempting to cancel lock.\n");
req = nlm_alloc_call(nlm_get_host(host));
if (!req)
return -ENOMEM;
req->a_flags = RPC_TASK_ASYNC;
nlmclnt_setlockargs(req, fl);
req->a_args.block = block;
atomic_inc(&req->a_count);
status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
NLMPROC_CANCEL, &nlmclnt_cancel_ops);
if (status == 0 && req->a_res.status == nlm_lck_denied)
status = -ENOLCK;
nlm_release_call(req);
return status;
}
static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
{
struct nlm_rqst *req = data;
u32 status = ntohl(req->a_res.status);
if (RPC_ASSASSINATED(task))
goto die;
if (task->tk_status < 0) {
dprintk("lockd: CANCEL call error %d, retrying.\n",
task->tk_status);
goto retry_cancel;
}
dprintk("lockd: cancel status %u (task %u)\n",
status, task->tk_pid);
switch (status) {
case NLM_LCK_GRANTED:
case NLM_LCK_DENIED_GRACE_PERIOD:
case NLM_LCK_DENIED:
/* Everything's good */
break;
case NLM_LCK_DENIED_NOLOCKS:
dprintk("lockd: CANCEL failed (server has no locks)\n");
goto retry_cancel;
default:
printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
status);
}
die:
return;
retry_cancel:
/* Don't ever retry more than 3 times */
if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
goto die;
lock_kernel();
nlm_rebind_host(req->a_host);
unlock_kernel();
rpc_restart_call(task);
rpc_delay(task, 30 * HZ);
}
static const struct rpc_call_ops nlmclnt_cancel_ops = {
.rpc_call_done = nlmclnt_cancel_callback,
.rpc_release = nlmclnt_rpc_release,
};
/*
* Convert an NLM status code to a generic kernel errno
*/
static int
nlm_stat_to_errno(__be32 status)
{
switch(ntohl(status)) {
case NLM_LCK_GRANTED:
return 0;
case NLM_LCK_DENIED:
return -EAGAIN;
case NLM_LCK_DENIED_NOLOCKS:
case NLM_LCK_DENIED_GRACE_PERIOD:
return -ENOLCK;
case NLM_LCK_BLOCKED:
printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
return -ENOLCK;
#ifdef CONFIG_LOCKD_V4
case NLM_DEADLCK:
return -EDEADLK;
case NLM_ROFS:
return -EROFS;
case NLM_STALE_FH:
return -ESTALE;
case NLM_FBIG:
return -EOVERFLOW;
case NLM_FAILED:
return -ENOLCK;
#endif
}
printk(KERN_NOTICE "lockd: unexpected server status %d\n", status);
return -ENOLCK;
}