/* * 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/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/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); static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host); /* * 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++; } 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 = (struct nlm_lockowner *)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); if (new != NULL) 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); 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); } static void nlmclnt_release_lockargs(struct nlm_rqst *req) { struct file_lock *fl = &req->a_args.lock.fl; if (fl->fl_ops && fl->fl_ops->fl_release_private) fl->fl_ops->fl_release_private(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) { nlmclnt_freegrantargs(call); 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) { struct file_lock *fl = &call->a_args.lock.fl; /* * 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); } if (fl->fl_ops && fl->fl_ops->fl_release_private) fl->fl_ops->fl_release_private(fl); } /* * 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->sighand->siglock, 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(); spin_unlock_irqrestore(¤t->sighand->siglock, flags); call = nlmclnt_alloc_call(); if (!call) { status = -ENOMEM; goto out_restore; } call->a_flags = RPC_TASK_ASYNC; } else { spin_unlock_irqrestore(¤t->sighand->siglock, 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; nlmclnt_locks_init_private(fl, 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; out_restore: spin_lock_irqsave(¤t->sighand->siglock, flags); current->blocked = oldset; recalc_sigpending(); spin_unlock_irqrestore(¤t->sighand->siglock, flags); done: dprintk("lockd: clnt proc returns %d\n", status); nlm_release_host(host); return status; } EXPORT_SYMBOL(nlmclnt_proc); /* * 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; } 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(PF_FREEZE); if (!signalled ()) status = 0; } finish_wait(queue, &wait); return status; } /* * Generic NLM call */ static 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 rpc_message msg = { .rpc_argp = argp, .rpc_resp = resp, }; 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. */ 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 rpc_message msg = { .rpc_argp = &req->a_args, .rpc_resp = &req->a_res, }; int status; dprintk("lockd: call procedure %d on %s (async)\n", (int)proc, host->h_name); /* 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]; /* bootstrap and kick off the async RPC call */ status = rpc_call_async(clnt, &msg, RPC_TASK_ASYNC, callback, req); return status; } static 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 rpc_message msg = { .rpc_argp = argp, .rpc_resp = resp, }; int status; dprintk("lockd: call procedure %d on %s (async)\n", (int)proc, host->h_name); /* 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]; /* Increment host refcount */ nlm_get_host(host); /* bootstrap and kick off the async RPC call */ 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; status = nlmclnt_call(req, NLMPROC_TEST); nlmclnt_release_lockargs(req); if (status < 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. */ 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_locks_copy_lock(struct file_lock *new, struct file_lock *fl) { memcpy(&new->fl_u.nfs_fl, &fl->fl_u.nfs_fl, sizeof(new->fl_u.nfs_fl)); nlm_get_lockowner(new->fl_u.nfs_fl.owner); } static void nlmclnt_locks_release_private(struct file_lock *fl) { nlm_put_lockowner(fl->fl_u.nfs_fl.owner); fl->fl_ops = NULL; } 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.flags = 0; fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner); fl->fl_ops = &nlmclnt_lock_ops; } static void 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(); } if (res < 0) printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __FUNCTION__); } /* * 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); status = -ENOLCK; goto out; } 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) goto out; } while (resp->status == NLM_LCK_BLOCKED && req->a_args.block); 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_flags |= FL_SLEEP; do_vfs_lock(fl); } status = nlm_stat_to_errno(resp->status); out: nlmclnt_release_lockargs(req); 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; 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) { status = nlmclnt_async_call(req, NLMPROC_UNLOCK, nlmclnt_unlock_callback); /* Hrmf... Do the unlock early since locks_remove_posix() * really expects us to free the lock synchronously */ do_vfs_lock(fl); if (status < 0) { nlmclnt_release_lockargs(req); kfree(req); } return status; } status = nlmclnt_call(req, NLMPROC_UNLOCK); nlmclnt_release_lockargs(req); if (status < 0) return status; do_vfs_lock(fl); 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); nlmclnt_release_lockargs(req); 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->sighand->siglock, flags); oldset = current->blocked; sigfillset(¤t->blocked); recalc_sigpending(); spin_unlock_irqrestore(¤t->sighand->siglock, 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) { nlmclnt_release_lockargs(req); kfree(req); } spin_lock_irqsave(¤t->sighand->siglock, flags); current->blocked = oldset; recalc_sigpending(); spin_unlock_irqrestore(¤t->sighand->siglock, 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); nlmclnt_release_lockargs(req); 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; }