clntproc.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 809 行 · 第 1/2 页

/*
 * linux/fs/lockd/clntproc.c
 *
 * RPC procedures for the client side NLM implementation
 *
 * Copyright (C) 1996, Olaf Kirch <[e-mail]>
 */

#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);
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(&current->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(&current->blocked);	/* Mask all signals */
		recalc_sigpending();
		spin_unlock_irqrestore(&current->sighand->siglock, flags);

		call = nlmclnt_alloc_call();
		if (!call) {
			status = -ENOMEM;
			goto out_restore;
		}
		call->a_flags = RPC_TASK_ASYNC;
	} else {
		spin_unlock_irqrestore(&current->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(&current->sighand->siglock, flags);
	current->blocked = oldset;
	recalc_sigpending();
	spin_unlock_irqrestore(&current->sighand->siglock, flags);

done:
	dprintk("lockd: clnt proc returns %d\n", status);
	nlm_release_host(host);
	return status;
}

/*
 * 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);
		if (!signalled ())
			status = 0;
	}
	finish_wait(queue, &wait);
	return status;
}

/*
 * 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 = {
		.rpc_argp	= argp,
		.rpc_resp	= resp,
	};
	int		status;

	dprintk("lockd: call procedure %d on %s\n",
			(int)proc, host->h_name);

	if (filp)
		msg.rpc_cred = nfs_file_cred(filp);

	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)