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lvm2/lib/locking/no_locking.c
Alasdair G Kergon 78533f72d3 locking: Introduce LCK_ACTIVATION.
Take a local file lock to prevent concurrent activation/deactivation of LVs.
Thin/cache types and an extension for cluster support are excluded for
now.

'lvchange -ay $lv' and 'lvchange -an $lv' should no longer cause trouble
if issued concurrently: the new lock should make sure they
activate/deactivate $lv one-after-the-other, instead of overlapping.

(If anyone wants to experiment with the cluster patch, please get in touch.)
2014-06-20 13:24:02 +01:00

127 lines
3.5 KiB
C

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* 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 Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "lib.h"
#include "locking.h"
#include "locking_types.h"
#include "lvm-string.h"
#include "activate.h"
#include <signal.h>
/*
* No locking
*/
static void _no_fin_locking(void)
{
}
static void _no_reset_locking(void)
{
}
static int _no_lock_resource(struct cmd_context *cmd, const char *resource,
uint32_t flags, struct logical_volume *lv)
{
switch (flags & LCK_SCOPE_MASK) {
case LCK_ACTIVATION:
break;
case LCK_VG:
if (!strcmp(resource, VG_SYNC_NAMES))
fs_unlock();
break;
case LCK_LV:
switch (flags & LCK_TYPE_MASK) {
case LCK_NULL:
return lv_deactivate(cmd, resource, lv_ondisk(lv));
case LCK_UNLOCK:
return lv_resume_if_active(cmd, resource, (flags & LCK_ORIGIN_ONLY) ? 1: 0, 0, (flags & LCK_REVERT) ? 1 : 0, lv_ondisk(lv));
case LCK_READ:
return lv_activate_with_filter(cmd, resource, 0, lv->status & LV_NOSCAN ? 1 : 0,
lv->status & LV_TEMPORARY ? 1 : 0, lv_ondisk(lv));
case LCK_WRITE:
return lv_suspend_if_active(cmd, resource, (flags & LCK_ORIGIN_ONLY) ? 1 : 0, 0, lv_ondisk(lv), lv);
case LCK_EXCL:
return lv_activate_with_filter(cmd, resource, 1, lv->status & LV_NOSCAN ? 1 : 0,
lv->status & LV_TEMPORARY ? 1 : 0, lv_ondisk(lv));
default:
break;
}
break;
default:
log_error("Unrecognised lock scope: %d",
flags & LCK_SCOPE_MASK);
return 0;
}
return 1;
}
static int _no_query_resource(const char *resource, int *mode)
{
log_very_verbose("Locking is disabled: Treating lock %s as not held.",
resource);
return 1;
}
static int _readonly_lock_resource(struct cmd_context *cmd,
const char *resource,
uint32_t flags, struct logical_volume *lv)
{
if ((flags & LCK_TYPE_MASK) == LCK_WRITE &&
(flags & LCK_SCOPE_MASK) == LCK_VG &&
!(flags & LCK_CACHE) &&
strcmp(resource, VG_GLOBAL)) {
log_error("Read-only locking type set. "
"Write locks are prohibited.");
return 0;
}
return _no_lock_resource(cmd, resource, flags, lv);
}
void init_no_locking(struct locking_type *locking, struct cmd_context *cmd __attribute__((unused)),
int suppress_messages)
{
locking->lock_resource = _no_lock_resource;
locking->query_resource = _no_query_resource;
locking->reset_locking = _no_reset_locking;
locking->fin_locking = _no_fin_locking;
locking->flags = LCK_CLUSTERED;
}
int init_readonly_locking(struct locking_type *locking, struct cmd_context *cmd __attribute__((unused)),
int suppress_messages)
{
locking->lock_resource = _readonly_lock_resource;
locking->query_resource = _no_query_resource;
locking->reset_locking = _no_reset_locking;
locking->fin_locking = _no_fin_locking;
locking->flags = 0;
return 1;
}
void init_dummy_locking(struct locking_type *locking, struct cmd_context *cmd __attribute__((unused)),
int suppress_messages)
{
locking->lock_resource = _readonly_lock_resource;
locking->query_resource = _no_query_resource;
locking->reset_locking = _no_reset_locking;
locking->fin_locking = _no_fin_locking;
locking->flags = LCK_CLUSTERED;
}