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/******************************************************************************
*******************************************************************************
**
** Copyright (C) 2005-2007 Red Hat, Inc. All rights reserved.
**
** This copyrighted material is made available to anyone wishing to use,
** modify, copy, or redistribute it subject to the terms and conditions
** of the GNU General Public License v.2.
**
*******************************************************************************
******************************************************************************/
#include "dlm_internal.h"
#include "member.h"
#include "lock.h"
#include "dir.h"
#include "config.h"
#include "requestqueue.h"
struct rq_entry {
struct list_head list;
int nodeid;
char request[0];
};
/*
* Requests received while the lockspace is in recovery get added to the
* request queue and processed when recovery is complete. This happens when
* the lockspace is suspended on some nodes before it is on others, or the
* lockspace is enabled on some while still suspended on others.
*/
void dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_header *hd)
{
struct rq_entry *e;
int length = hd->h_length;
e = kmalloc(sizeof(struct rq_entry) + length, GFP_KERNEL);
if (!e) {
log_print("dlm_add_requestqueue: out of memory len %d", length);
return;
}
e->nodeid = nodeid;
memcpy(e->request, hd, length);
mutex_lock(&ls->ls_requestqueue_mutex);
list_add_tail(&e->list, &ls->ls_requestqueue);
mutex_unlock(&ls->ls_requestqueue_mutex);
}
/*
* Called by dlm_recoverd to process normal messages saved while recovery was
* happening. Normal locking has been enabled before this is called. dlm_recv
* upon receiving a message, will wait for all saved messages to be drained
* here before processing the message it got. If a new dlm_ls_stop() arrives
* while we're processing these saved messages, it may block trying to suspend
* dlm_recv if dlm_recv is waiting for us in dlm_wait_requestqueue. In that
* case, we don't abort since locking_stopped is still 0. If dlm_recv is not
* waiting for us, then this processing may be aborted due to locking_stopped.
*/
int dlm_process_requestqueue(struct dlm_ls *ls)
{
struct rq_entry *e;
int error = 0;
mutex_lock(&ls->ls_requestqueue_mutex);
for (;;) {
if (list_empty(&ls->ls_requestqueue)) {
mutex_unlock(&ls->ls_requestqueue_mutex);
error = 0;
break;
}
e = list_entry(ls->ls_requestqueue.next, struct rq_entry, list);
mutex_unlock(&ls->ls_requestqueue_mutex);
dlm_receive_message_saved(ls, (struct dlm_message *)e->request);
mutex_lock(&ls->ls_requestqueue_mutex);
list_del(&e->list);
kfree(e);
if (dlm_locking_stopped(ls)) {
log_debug(ls, "process_requestqueue abort running");
mutex_unlock(&ls->ls_requestqueue_mutex);
error = -EINTR;
break;
}
schedule();
}
return error;
}
/*
* After recovery is done, locking is resumed and dlm_recoverd takes all the
* saved requests and processes them as they would have been by dlm_recv. At
* the same time, dlm_recv will start receiving new requests from remote nodes.
* We want to delay dlm_recv processing new requests until dlm_recoverd has
* finished processing the old saved requests. We don't check for locking
* stopped here because dlm_ls_stop won't stop locking until it's suspended us
* (dlm_recv).
*/
void dlm_wait_requestqueue(struct dlm_ls *ls)
{
for (;;) {
mutex_lock(&ls->ls_requestqueue_mutex);
if (list_empty(&ls->ls_requestqueue))
break;
mutex_unlock(&ls->ls_requestqueue_mutex);
schedule();
}
mutex_unlock(&ls->ls_requestqueue_mutex);
}
static int purge_request(struct dlm_ls *ls, struct dlm_message *ms, int nodeid)
{
uint32_t type = ms->m_type;
/* the ls is being cleaned up and freed by release_lockspace */
if (!ls->ls_count)
return 1;
if (dlm_is_removed(ls, nodeid))
return 1;
/* directory operations are always purged because the directory is
always rebuilt during recovery and the lookups resent */
if (type == DLM_MSG_REMOVE ||
type == DLM_MSG_LOOKUP ||
type == DLM_MSG_LOOKUP_REPLY)
return 1;
if (!dlm_no_directory(ls))
return 0;
/* with no directory, the master is likely to change as a part of
recovery; requests to/from the defunct master need to be purged */
switch (type) {
case DLM_MSG_REQUEST:
case DLM_MSG_CONVERT:
case DLM_MSG_UNLOCK:
case DLM_MSG_CANCEL:
/* we're no longer the master of this resource, the sender
will resend to the new master (see waiter_needs_recovery) */
if (dlm_hash2nodeid(ls, ms->m_hash) != dlm_our_nodeid())
return 1;
break;
case DLM_MSG_REQUEST_REPLY:
case DLM_MSG_CONVERT_REPLY:
case DLM_MSG_UNLOCK_REPLY:
case DLM_MSG_CANCEL_REPLY:
case DLM_MSG_GRANT:
/* this reply is from the former master of the resource,
we'll resend to the new master if needed */
if (dlm_hash2nodeid(ls, ms->m_hash) != nodeid)
return 1;
break;
}
return 0;
}
void dlm_purge_requestqueue(struct dlm_ls *ls)
{
struct dlm_message *ms;
struct rq_entry *e, *safe;
mutex_lock(&ls->ls_requestqueue_mutex);
list_for_each_entry_safe(e, safe, &ls->ls_requestqueue, list) {
ms = (struct dlm_message *) e->request;
if (purge_request(ls, ms, e->nodeid)) {
list_del(&e->list);
kfree(e);
}
}
mutex_unlock(&ls->ls_requestqueue_mutex);
}
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