2005-04-16 22:20:36 +00:00
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/* kafsasyncd.c: AFS asynchronous operation daemon
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*
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* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*
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* The AFS async daemon is used to the following:
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* - probe "dead" servers to see whether they've come back to life yet.
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* - probe "live" servers that we haven't talked to for a while to see if they are better
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* candidates for serving than what we're currently using
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* - poll volume location servers to keep up to date volume location lists
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/completion.h>
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#include "cell.h"
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#include "server.h"
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#include "volume.h"
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#include "kafsasyncd.h"
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#include "kafstimod.h"
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#include <rxrpc/call.h>
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#include <asm/errno.h>
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#include "internal.h"
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static DECLARE_COMPLETION(kafsasyncd_alive);
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static DECLARE_COMPLETION(kafsasyncd_dead);
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static DECLARE_WAIT_QUEUE_HEAD(kafsasyncd_sleepq);
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static struct task_struct *kafsasyncd_task;
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static int kafsasyncd_die;
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static int kafsasyncd(void *arg);
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static LIST_HEAD(kafsasyncd_async_attnq);
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static LIST_HEAD(kafsasyncd_async_busyq);
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static DEFINE_SPINLOCK(kafsasyncd_async_lock);
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static void kafsasyncd_null_call_attn_func(struct rxrpc_call *call)
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{
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}
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static void kafsasyncd_null_call_error_func(struct rxrpc_call *call)
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{
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}
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/*****************************************************************************/
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/*
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* start the async daemon
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*/
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int afs_kafsasyncd_start(void)
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{
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int ret;
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ret = kernel_thread(kafsasyncd, NULL, 0);
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if (ret < 0)
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return ret;
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wait_for_completion(&kafsasyncd_alive);
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return ret;
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} /* end afs_kafsasyncd_start() */
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/*****************************************************************************/
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/*
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* stop the async daemon
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*/
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void afs_kafsasyncd_stop(void)
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{
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/* get rid of my daemon */
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kafsasyncd_die = 1;
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wake_up(&kafsasyncd_sleepq);
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wait_for_completion(&kafsasyncd_dead);
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} /* end afs_kafsasyncd_stop() */
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/*****************************************************************************/
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/*
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* probing daemon
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*/
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static int kafsasyncd(void *arg)
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{
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struct afs_async_op *op;
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int die;
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DECLARE_WAITQUEUE(myself, current);
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kafsasyncd_task = current;
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printk("kAFS: Started kafsasyncd %d\n", current->pid);
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daemonize("kafsasyncd");
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complete(&kafsasyncd_alive);
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/* loop around looking for things to attend to */
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do {
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set_current_state(TASK_INTERRUPTIBLE);
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add_wait_queue(&kafsasyncd_sleepq, &myself);
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for (;;) {
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if (!list_empty(&kafsasyncd_async_attnq) ||
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signal_pending(current) ||
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kafsasyncd_die)
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break;
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schedule();
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set_current_state(TASK_INTERRUPTIBLE);
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}
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remove_wait_queue(&kafsasyncd_sleepq, &myself);
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set_current_state(TASK_RUNNING);
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2005-06-25 06:13:50 +00:00
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try_to_freeze();
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2005-04-16 22:20:36 +00:00
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/* discard pending signals */
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afs_discard_my_signals();
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die = kafsasyncd_die;
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/* deal with the next asynchronous operation requiring
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* attention */
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if (!list_empty(&kafsasyncd_async_attnq)) {
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struct afs_async_op *op;
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_debug("@@@ Begin Asynchronous Operation");
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op = NULL;
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spin_lock(&kafsasyncd_async_lock);
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if (!list_empty(&kafsasyncd_async_attnq)) {
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op = list_entry(kafsasyncd_async_attnq.next,
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struct afs_async_op, link);
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2006-06-26 07:24:46 +00:00
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list_move_tail(&op->link,
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2005-04-16 22:20:36 +00:00
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&kafsasyncd_async_busyq);
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}
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spin_unlock(&kafsasyncd_async_lock);
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_debug("@@@ Operation %p {%p}\n",
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op, op ? op->ops : NULL);
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if (op)
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op->ops->attend(op);
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_debug("@@@ End Asynchronous Operation");
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}
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} while(!die);
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/* need to kill all outstanding asynchronous operations before
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* exiting */
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kafsasyncd_task = NULL;
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spin_lock(&kafsasyncd_async_lock);
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/* fold the busy and attention queues together */
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list_splice_init(&kafsasyncd_async_busyq,
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&kafsasyncd_async_attnq);
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/* dequeue kafsasyncd from all their wait queues */
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list_for_each_entry(op, &kafsasyncd_async_attnq, link) {
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op->call->app_attn_func = kafsasyncd_null_call_attn_func;
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op->call->app_error_func = kafsasyncd_null_call_error_func;
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remove_wait_queue(&op->call->waitq, &op->waiter);
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}
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spin_unlock(&kafsasyncd_async_lock);
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/* abort all the operations */
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while (!list_empty(&kafsasyncd_async_attnq)) {
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op = list_entry(kafsasyncd_async_attnq.next, struct afs_async_op, link);
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list_del_init(&op->link);
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rxrpc_call_abort(op->call, -EIO);
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rxrpc_put_call(op->call);
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op->call = NULL;
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op->ops->discard(op);
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}
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/* and that's all */
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_leave("");
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complete_and_exit(&kafsasyncd_dead, 0);
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} /* end kafsasyncd() */
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/*****************************************************************************/
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/*
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* begin an operation
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* - place operation on busy queue
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*/
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void afs_kafsasyncd_begin_op(struct afs_async_op *op)
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{
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_enter("");
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spin_lock(&kafsasyncd_async_lock);
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init_waitqueue_entry(&op->waiter, kafsasyncd_task);
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add_wait_queue(&op->call->waitq, &op->waiter);
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2006-06-26 07:24:46 +00:00
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list_move_tail(&op->link, &kafsasyncd_async_busyq);
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2005-04-16 22:20:36 +00:00
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spin_unlock(&kafsasyncd_async_lock);
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_leave("");
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} /* end afs_kafsasyncd_begin_op() */
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/*****************************************************************************/
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/*
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* request attention for an operation
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* - move to attention queue
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*/
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void afs_kafsasyncd_attend_op(struct afs_async_op *op)
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{
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_enter("");
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spin_lock(&kafsasyncd_async_lock);
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2006-06-26 07:24:46 +00:00
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list_move_tail(&op->link, &kafsasyncd_async_attnq);
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2005-04-16 22:20:36 +00:00
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spin_unlock(&kafsasyncd_async_lock);
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wake_up(&kafsasyncd_sleepq);
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_leave("");
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} /* end afs_kafsasyncd_attend_op() */
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/*****************************************************************************/
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/*
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* terminate an operation
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* - remove from either queue
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*/
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void afs_kafsasyncd_terminate_op(struct afs_async_op *op)
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{
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_enter("");
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spin_lock(&kafsasyncd_async_lock);
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if (!list_empty(&op->link)) {
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list_del_init(&op->link);
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remove_wait_queue(&op->call->waitq, &op->waiter);
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}
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spin_unlock(&kafsasyncd_async_lock);
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wake_up(&kafsasyncd_sleepq);
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_leave("");
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} /* end afs_kafsasyncd_terminate_op() */
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