linux/fs/dlm/ast.c
David Teigland 32f105a123 [DLM] down conversion clearing flags
The down-conversion optimization was resulting in the lkb flags being
cleared because the stub message reply had no flags value set.  Copy the
current flags into the stub message so they'll be copied back into the lkb
as part of processing the fake reply.  Also add an assertion to catch this
error more directly if it exists elsewhere.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-08-23 16:07:31 -04:00

173 lines
3.7 KiB
C

/******************************************************************************
*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
** Copyright (C) 2004-2005 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 "lock.h"
#include "user.h"
#define WAKE_ASTS 0
static struct list_head ast_queue;
static spinlock_t ast_queue_lock;
static struct task_struct * astd_task;
static unsigned long astd_wakeflags;
static struct mutex astd_running;
void dlm_del_ast(struct dlm_lkb *lkb)
{
spin_lock(&ast_queue_lock);
if (lkb->lkb_ast_type & (AST_COMP | AST_BAST))
list_del(&lkb->lkb_astqueue);
spin_unlock(&ast_queue_lock);
}
void dlm_add_ast(struct dlm_lkb *lkb, int type)
{
if (lkb->lkb_flags & DLM_IFL_USER) {
dlm_user_add_ast(lkb, type);
return;
}
DLM_ASSERT(lkb->lkb_astaddr != DLM_FAKE_USER_AST, dlm_print_lkb(lkb););
spin_lock(&ast_queue_lock);
if (!(lkb->lkb_ast_type & (AST_COMP | AST_BAST))) {
kref_get(&lkb->lkb_ref);
list_add_tail(&lkb->lkb_astqueue, &ast_queue);
}
lkb->lkb_ast_type |= type;
spin_unlock(&ast_queue_lock);
set_bit(WAKE_ASTS, &astd_wakeflags);
wake_up_process(astd_task);
}
static void process_asts(void)
{
struct dlm_ls *ls = NULL;
struct dlm_rsb *r = NULL;
struct dlm_lkb *lkb;
void (*cast) (long param);
void (*bast) (long param, int mode);
int type = 0, found, bmode;
for (;;) {
found = 0;
spin_lock(&ast_queue_lock);
list_for_each_entry(lkb, &ast_queue, lkb_astqueue) {
r = lkb->lkb_resource;
ls = r->res_ls;
if (dlm_locking_stopped(ls))
continue;
list_del(&lkb->lkb_astqueue);
type = lkb->lkb_ast_type;
lkb->lkb_ast_type = 0;
found = 1;
break;
}
spin_unlock(&ast_queue_lock);
if (!found)
break;
cast = lkb->lkb_astaddr;
bast = lkb->lkb_bastaddr;
bmode = lkb->lkb_bastmode;
if ((type & AST_COMP) && cast)
cast(lkb->lkb_astparam);
/* FIXME: Is it safe to look at lkb_grmode here
without doing a lock_rsb() ?
Look at other checks in v1 to avoid basts. */
if ((type & AST_BAST) && bast)
if (!dlm_modes_compat(lkb->lkb_grmode, bmode))
bast(lkb->lkb_astparam, bmode);
/* this removes the reference added by dlm_add_ast
and may result in the lkb being freed */
dlm_put_lkb(lkb);
schedule();
}
}
static inline int no_asts(void)
{
int ret;
spin_lock(&ast_queue_lock);
ret = list_empty(&ast_queue);
spin_unlock(&ast_queue_lock);
return ret;
}
static int dlm_astd(void *data)
{
while (!kthread_should_stop()) {
set_current_state(TASK_INTERRUPTIBLE);
if (!test_bit(WAKE_ASTS, &astd_wakeflags))
schedule();
set_current_state(TASK_RUNNING);
mutex_lock(&astd_running);
if (test_and_clear_bit(WAKE_ASTS, &astd_wakeflags))
process_asts();
mutex_unlock(&astd_running);
}
return 0;
}
void dlm_astd_wake(void)
{
if (!no_asts()) {
set_bit(WAKE_ASTS, &astd_wakeflags);
wake_up_process(astd_task);
}
}
int dlm_astd_start(void)
{
struct task_struct *p;
int error = 0;
INIT_LIST_HEAD(&ast_queue);
spin_lock_init(&ast_queue_lock);
mutex_init(&astd_running);
p = kthread_run(dlm_astd, NULL, "dlm_astd");
if (IS_ERR(p))
error = PTR_ERR(p);
else
astd_task = p;
return error;
}
void dlm_astd_stop(void)
{
kthread_stop(astd_task);
}
void dlm_astd_suspend(void)
{
mutex_lock(&astd_running);
}
void dlm_astd_resume(void)
{
mutex_unlock(&astd_running);
}