kernel-ark/fs/dlm/requestqueue.c
David Teigland 573c24c4af dlm: always use GFP_NOFS
Replace all GFP_KERNEL and ls_allocation with GFP_NOFS.
ls_allocation would be GFP_KERNEL for userland lockspaces
and GFP_NOFS for file system lockspaces.

It was discovered that any lockspaces on the system can
affect all others by triggering memory reclaim in the
file system which could in turn call back into the dlm
to acquire locks, deadlocking dlm threads that were
shared by all lockspaces, like dlm_recv.

Signed-off-by: David Teigland <teigland@redhat.com>
2009-11-30 16:34:43 -06:00

189 lines
5.3 KiB
C

/******************************************************************************
*******************************************************************************
**
** 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;
struct dlm_message request;
};
/*
* 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_message *ms)
{
struct rq_entry *e;
int length = ms->m_header.h_length - sizeof(struct dlm_message);
e = kmalloc(sizeof(struct rq_entry) + length, GFP_NOFS);
if (!e) {
log_print("dlm_add_requestqueue: out of memory len %d", length);
return;
}
e->nodeid = nodeid;
memcpy(&e->request, ms, ms->m_header.h_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, &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 = &e->request;
if (purge_request(ls, ms, e->nodeid)) {
list_del(&e->list);
kfree(e);
}
}
mutex_unlock(&ls->ls_requestqueue_mutex);
}