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b5f8f452ac
Offer lock-free access to display virtual machine or clustered VG metadata while it might be in use.
125 lines
3.5 KiB
C
125 lines
3.5 KiB
C
/*
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* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
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* Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
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*
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* This file is part of LVM2.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU Lesser General Public License v.2.1.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "lib.h"
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#include "locking.h"
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#include "locking_types.h"
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#include "lvm-string.h"
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#include "activate.h"
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#include <signal.h>
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/*
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* No locking
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*/
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static void _no_fin_locking(void)
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{
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}
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static void _no_reset_locking(void)
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{
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}
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static int _no_lock_resource(struct cmd_context *cmd, const char *resource,
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uint32_t flags, struct logical_volume *lv)
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{
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switch (flags & LCK_SCOPE_MASK) {
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case LCK_VG:
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if (!strcmp(resource, VG_SYNC_NAMES))
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fs_unlock();
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break;
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case LCK_LV:
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switch (flags & LCK_TYPE_MASK) {
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case LCK_NULL:
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return lv_deactivate(cmd, resource, lv_ondisk(lv));
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case LCK_UNLOCK:
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return lv_resume_if_active(cmd, resource, (flags & LCK_ORIGIN_ONLY) ? 1: 0, 0, (flags & LCK_REVERT) ? 1 : 0, lv_ondisk(lv));
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case LCK_READ:
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return lv_activate_with_filter(cmd, resource, 0, lv->status & LV_NOSCAN ? 1 : 0,
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lv->status & LV_TEMPORARY ? 1 : 0, lv_ondisk(lv));
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case LCK_WRITE:
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return lv_suspend_if_active(cmd, resource, (flags & LCK_ORIGIN_ONLY) ? 1 : 0, 0, lv_ondisk(lv), lv);
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case LCK_EXCL:
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return lv_activate_with_filter(cmd, resource, 1, lv->status & LV_NOSCAN ? 1 : 0,
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lv->status & LV_TEMPORARY ? 1 : 0, lv_ondisk(lv));
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default:
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break;
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}
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break;
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default:
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log_error("Unrecognised lock scope: %d",
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flags & LCK_SCOPE_MASK);
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return 0;
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}
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return 1;
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}
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static int _no_query_resource(const char *resource, int *mode)
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{
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log_very_verbose("Locking is disabled: Treating lock %s as not held.",
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resource);
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return 1;
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}
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static int _readonly_lock_resource(struct cmd_context *cmd,
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const char *resource,
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uint32_t flags, struct logical_volume *lv)
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{
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if ((flags & LCK_TYPE_MASK) == LCK_WRITE &&
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(flags & LCK_SCOPE_MASK) == LCK_VG &&
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!(flags & LCK_CACHE) &&
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strcmp(resource, VG_GLOBAL)) {
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log_error("Read-only locking type set. "
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"Write locks are prohibited.");
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return 0;
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}
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return _no_lock_resource(cmd, resource, flags, lv);
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}
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void init_no_locking(struct locking_type *locking, struct cmd_context *cmd __attribute__((unused)),
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int suppress_messages)
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{
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locking->lock_resource = _no_lock_resource;
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locking->query_resource = _no_query_resource;
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locking->reset_locking = _no_reset_locking;
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locking->fin_locking = _no_fin_locking;
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locking->flags = LCK_CLUSTERED;
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}
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int init_readonly_locking(struct locking_type *locking, struct cmd_context *cmd __attribute__((unused)),
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int suppress_messages)
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{
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locking->lock_resource = _readonly_lock_resource;
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locking->query_resource = _no_query_resource;
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locking->reset_locking = _no_reset_locking;
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locking->fin_locking = _no_fin_locking;
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locking->flags = 0;
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return 1;
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}
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void init_dummy_locking(struct locking_type *locking, struct cmd_context *cmd __attribute__((unused)),
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int suppress_messages)
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{
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locking->lock_resource = _readonly_lock_resource;
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locking->query_resource = _no_query_resource;
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locking->reset_locking = _no_reset_locking;
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locking->fin_locking = _no_fin_locking;
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locking->flags = LCK_CLUSTERED;
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}
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