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/*
* linux/fs/lockd/clntproc.c
*
* RPC procedures for the client side NLM implementation
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/config.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/nfs_fs.h>
#include <linux/utsname.h>
#include <linux/smp_lock.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svc.h>
#include <linux/lockd/lockd.h>
#include <linux/lockd/sm_inter.h>
#define NLMDBG_FACILITY NLMDBG_CLIENT
#define NLMCLNT_GRACE_WAIT (5*HZ)
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 void nlmclnt_unlock_callback(struct rpc_task *);
static void nlmclnt_cancel_callback(struct rpc_task *);
static int nlm_stat_to_errno(u32 stat);
/*
* Cookie counter for NLM requests
*/
static u32 nlm_cookie = 0x1234;
static inline void nlmclnt_next_cookie(struct nlm_cookie *c)
{
memcpy(c->data, &nlm_cookie, 4);
memset(c->data+4, 0, 4);
c->len=4;
nlm_cookie++;
}
/*
* Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
*/
static inline 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);
argp->state = nsm_local_state;
memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh));
lock->caller = system_utsname.nodename;
lock->oh.data = req->a_owner;
lock->oh.len = sprintf(req->a_owner, "%d@%s",
current->pid, system_utsname.nodename);
locks_copy_lock(&lock->fl, fl);
}
/*
* Initialize arguments for GRANTED call. The nlm_rqst structure
* has been cleared already.
*/
int
nlmclnt_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
{
locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
call->a_args.lock.caller = system_utsname.nodename;
call->a_args.lock.oh.len = lock->oh.len;
/* set default data area */
call->a_args.lock.oh.data = call->a_owner;
if (lock->oh.len > NLMCLNT_OHSIZE) {
void *data = kmalloc(lock->oh.len, GFP_KERNEL);
if (!data)
return 0;
call->a_args.lock.oh.data = (u8 *) data;
}
memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
return 1;
}
void
nlmclnt_freegrantargs(struct nlm_rqst *call)
{
/*
* Check whether we allocated memory for the owner.
*/
if (call->a_args.lock.oh.data != (u8 *) call->a_owner) {
kfree(call->a_args.lock.oh.data);
}
}
/*
* This is the main entry point for the NLM client.
*/
int
nlmclnt_proc(struct inode *inode, int cmd, struct file_lock *fl)
{
struct nfs_server *nfssrv = NFS_SERVER(inode);
struct nlm_host *host;
struct nlm_rqst reqst, *call = &reqst;
sigset_t oldset;
unsigned long flags;
int status, proto, vers;
vers = (NFS_PROTO(inode)->version == 3) ? 4 : 1;
if (NFS_PROTO(inode)->version > 3) {
printk(KERN_NOTICE "NFSv4 file locking not implemented!\n");
return -ENOLCK;
}
/* Retrieve transport protocol from NFS client */
proto = NFS_CLIENT(inode)->cl_xprt->prot;
if (!(host = nlmclnt_lookup_host(NFS_ADDR(inode), proto, vers)))
return -ENOLCK;
/* Create RPC client handle if not there, and copy soft
* and intr flags from NFS client. */
if (host->h_rpcclnt == NULL) {
struct rpc_clnt *clnt;
/* Bind an rpc client to this host handle (does not
* perform a portmapper lookup) */
if (!(clnt = nlm_bind_host(host))) {
status = -ENOLCK;
goto done;
}
clnt->cl_softrtry = nfssrv->client->cl_softrtry;
clnt->cl_intr = nfssrv->client->cl_intr;
clnt->cl_chatty = nfssrv->client->cl_chatty;
}
/* Keep the old signal mask */
spin_lock_irqsave(¤t->sigmask_lock, flags);
oldset = current->blocked;
/* If we're cleaning up locks because the process is exiting,
* perform the RPC call asynchronously. */
if ((IS_SETLK(cmd) || IS_SETLKW(cmd))
&& fl->fl_type == F_UNLCK
&& (current->flags & PF_EXITING)) {
sigfillset(¤t->blocked); /* Mask all signals */
recalc_sigpending(current);
spin_unlock_irqrestore(¤t->sigmask_lock, flags);
call = nlmclnt_alloc_call();
if (!call) {
status = -ENOMEM;
goto out_restore;
}
call->a_flags = RPC_TASK_ASYNC;
} else {
spin_unlock_irqrestore(¤t->sigmask_lock, flags);
memset(call, 0, sizeof(*call));
locks_init_lock(&call->a_args.lock.fl);
locks_init_lock(&call->a_res.lock.fl);
}
call->a_host = host;
/* Set up the argument struct */
nlmclnt_setlockargs(call, fl);
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;
if (status < 0 && (call->a_flags & RPC_TASK_ASYNC))
kfree(call);
out_restore:
spin_lock_irqsave(¤t->sigmask_lock, flags);
current->blocked = oldset;
recalc_sigpending(current);
spin_unlock_irqrestore(¤t->sigmask_lock, flags);
done:
dprintk("lockd: clnt proc returns %d\n", status);
nlm_release_host(host);
return status;
}
/*
* Wait while server is in grace period
*/
static inline int
nlmclnt_grace_wait(struct nlm_host *host)
{
if (!host->h_reclaiming)
interruptible_sleep_on_timeout(&host->h_gracewait, 10*HZ);
else
interruptible_sleep_on(&host->h_gracewait);
return signalled()? -ERESTARTSYS : 0;
}
/*
* Allocate an NLM RPC call struct
*/
struct nlm_rqst *
nlmclnt_alloc_call(void)
{
struct nlm_rqst *call;
while (!signalled()) {
call = (struct nlm_rqst *) kmalloc(sizeof(struct nlm_rqst), GFP_KERNEL);
if (call) {
memset(call, 0, sizeof(*call));
locks_init_lock(&call->a_args.lock.fl);
locks_init_lock(&call->a_res.lock.fl);
return call;
}
printk("nlmclnt_alloc_call: failed, waiting for memory\n");
current->state = TASK_INTERRUPTIBLE;
schedule_timeout(5*HZ);
}
return NULL;
}
/*
* Generic NLM call
*/
int
nlmclnt_call(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 file *filp = argp->lock.fl.fl_file;
struct rpc_message msg;
int status;
dprintk("lockd: call procedure %s on %s\n",
nlm_procname(proc), host->h_name);
msg.rpc_proc = proc;
msg.rpc_argp = argp;
msg.rpc_resp = resp;
if (filp)
msg.rpc_cred = nfs_file_cred(filp);
else
msg.rpc_cred = NULL;
do {
if (host->h_reclaiming && !argp->reclaim) {
interruptible_sleep_on(&host->h_gracewait);
continue;
}
/* If we have no RPC client yet, create one. */
if ((clnt = nlm_bind_host(host)) == NULL)
return -ENOLCK;
/* 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 {
dprintk("lockd: server returns status %d\n", resp->status);
return 0; /* Okay, call complete */
}
/* Back off a little and try again */
interruptible_sleep_on_timeout(&host->h_gracewait, 15*HZ);
/* When the lock requested by F_SETLKW isn't available,
we will wait until the request can be satisfied. If
a signal is received during wait, we should return
-EINTR. */
if (signalled ()) {
status = -EINTR;
break;
}
} while (1);
return status;
}
/*
* Generic NLM call, async version.
*/
int
nlmsvc_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback)
{
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;
int status;
dprintk("lockd: call procedure %s on %s (async)\n",
nlm_procname(proc), host->h_name);
/* If we have no RPC client yet, create one. */
if ((clnt = nlm_bind_host(host)) == NULL)
return -ENOLCK;
/* bootstrap and kick off the async RPC call */
msg.rpc_proc = proc;
msg.rpc_argp = argp;
msg.rpc_resp =resp;
msg.rpc_cred = NULL;
status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req);
return status;
}
int
nlmclnt_async_call(struct nlm_rqst *req, u32 proc, rpc_action callback)
{
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 file *file = argp->lock.fl.fl_file;
struct rpc_message msg;
int status;
dprintk("lockd: call procedure %s on %s (async)\n",
nlm_procname(proc), host->h_name);
/* If we have no RPC client yet, create one. */
if ((clnt = nlm_bind_host(host)) == NULL)
return -ENOLCK;
/* bootstrap and kick off the async RPC call */
msg.rpc_proc = proc;
msg.rpc_argp = argp;
msg.rpc_resp =resp;
if (file)
msg.rpc_cred = nfs_file_cred(file);
else
msg.rpc_cred = NULL;
/* Increment host refcount */
nlm_get_host(host);
status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req);
if (status < 0)
nlm_release_host(host);
return status;
}
/*
* TEST for the presence of a conflicting lock
*/
static int
nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
{
int status;
if ((status = nlmclnt_call(req, NLMPROC_TEST)) < 0)
return status;
status = req->a_res.status;
if (status == NLM_LCK_GRANTED) {
fl->fl_type = F_UNLCK;
} if (status == NLM_LCK_DENIED) {
/*
* Report the conflicting lock back to the application.
* FIXME: Is it OK to report the pid back as well?
*/
locks_copy_lock(fl, &req->a_res.lock.fl);
/* fl->fl_pid = 0; */
} else {
return nlm_stat_to_errno(req->a_res.status);
}
return 0;
}
static
void nlmclnt_insert_lock_callback(struct file_lock *fl)
{
nlm_get_host(fl->fl_u.nfs_fl.host);
}
static
void nlmclnt_remove_lock_callback(struct file_lock *fl)
{
if (fl->fl_u.nfs_fl.host) {
nlm_release_host(fl->fl_u.nfs_fl.host);
fl->fl_u.nfs_fl.host = NULL;
}
}
/*
* 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 nlm_host *host = req->a_host;
struct nlm_res *resp = &req->a_res;
int status;
if (!host->h_monitored && nsm_monitor(host) < 0) {
printk(KERN_NOTICE "lockd: failed to monitor %s\n",
host->h_name);
return -ENOLCK;
}
do {
if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0) {
if (resp->status != NLM_LCK_BLOCKED)
break;
status = nlmclnt_block(host, fl, &resp->status);
}
if (status < 0)
return status;
} while (resp->status == NLM_LCK_BLOCKED);
if (resp->status == NLM_LCK_GRANTED) {
fl->fl_u.nfs_fl.state = host->h_state;
fl->fl_u.nfs_fl.flags |= NFS_LCK_GRANTED;
fl->fl_u.nfs_fl.host = host;
fl->fl_insert = nlmclnt_insert_lock_callback;
fl->fl_remove = nlmclnt_remove_lock_callback;
}
return nlm_stat_to_errno(resp->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;
if ((status = nlmclnt_call(req, NLMPROC_LOCK)) >= 0
&& req->a_res.status == NLM_LCK_GRANTED)
return 0;
printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
"(errno %d, status %d)\n", fl->fl_pid,
status, 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_res *resp = &req->a_res;
int status;
/* Clean the GRANTED flag now so the lock doesn't get
* reclaimed while we're stuck in the unlock call. */
fl->fl_u.nfs_fl.flags &= ~NFS_LCK_GRANTED;
if (req->a_flags & RPC_TASK_ASYNC) {
return nlmclnt_async_call(req, NLMPROC_UNLOCK,
nlmclnt_unlock_callback);
}
if ((status = nlmclnt_call(req, NLMPROC_UNLOCK)) < 0)
return status;
if (resp->status == NLM_LCK_GRANTED)
return 0;
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... */
return -ENOLCK;
}
static void
nlmclnt_unlock_callback(struct rpc_task *task)
{
struct nlm_rqst *req = (struct nlm_rqst *) task->tk_calldata;
int status = 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:
nlm_release_host(req->a_host);
kfree(req);
return;
retry_rebind:
nlm_rebind_host(req->a_host);
retry_unlock:
rpc_restart_call(task);
}
/*
* 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.
*/
int
nlmclnt_cancel(struct nlm_host *host, struct file_lock *fl)
{
struct nlm_rqst *req;
unsigned long flags;
sigset_t oldset;
int status;
/* Block all signals while setting up call */
spin_lock_irqsave(¤t->sigmask_lock, flags);
oldset = current->blocked;
sigfillset(¤t->blocked);
recalc_sigpending(current);
spin_unlock_irqrestore(¤t->sigmask_lock, flags);
req = nlmclnt_alloc_call();
if (!req)
return -ENOMEM;
req->a_host = host;
req->a_flags = RPC_TASK_ASYNC;
nlmclnt_setlockargs(req, fl);
status = nlmclnt_async_call(req, NLMPROC_CANCEL,
nlmclnt_cancel_callback);
if (status < 0)
kfree(req);
spin_lock_irqsave(¤t->sigmask_lock, flags);
current->blocked = oldset;
recalc_sigpending(current);
spin_unlock_irqrestore(¤t->sigmask_lock, flags);
return status;
}
static void
nlmclnt_cancel_callback(struct rpc_task *task)
{
struct nlm_rqst *req = (struct nlm_rqst *) task->tk_calldata;
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 %d (task %d)\n",
req->a_res.status, task->tk_pid);
switch (req->a_res.status) {
case NLM_LCK_GRANTED:
case NLM_LCK_DENIED_GRACE_PERIOD:
/* 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",
req->a_res.status);
}
die:
nlm_release_host(req->a_host);
kfree(req);
return;
retry_cancel:
nlm_rebind_host(req->a_host);
rpc_restart_call(task);
rpc_delay(task, 30 * HZ);
}
/*
* Convert an NLM status code to a generic kernel errno
*/
static int
nlm_stat_to_errno(u32 status)
{
switch(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;
}
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