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/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2014 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 "activate.h"
#include "config.h"
#include "defaults.h"
#include "lvm-string.h"
#include "lvm-flock.h"
#include "lvmcache.h"
#include <limits.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <signal.h>
static char _lock_dir[PATH_MAX];
static void _fin_file_locking(void)
{
release_flocks(1);
}
static void _reset_file_locking(void)
{
release_flocks(0);
}
static int _file_lock_resource(struct cmd_context *cmd, const char *resource,
uint32_t flags, struct logical_volume *lv)
{
char lockfile[PATH_MAX];
unsigned origin_only = (flags & LCK_ORIGIN_ONLY) ? 1 : 0;
unsigned revert = (flags & LCK_REVERT) ? 1 : 0;
switch (flags & LCK_SCOPE_MASK) {
case LCK_VG:
/* Skip cache refresh for VG_GLOBAL - the caller handles it */
if (strcmp(resource, VG_GLOBAL))
lvmcache_drop_metadata(resource, 0);
if (!strcmp(resource, VG_SYNC_NAMES))
fs_unlock();
/* LCK_CACHE does not require a real lock */
if (flags & LCK_CACHE)
break;
if (is_orphan_vg(resource) || is_global_vg(resource)) {
if (dm_snprintf(lockfile, sizeof(lockfile),
"%s/P_%s", _lock_dir, resource + 1) < 0) {
log_error("Too long locking filename %s/P_%s.",
_lock_dir, resource + 1);
return 0;
}
} else
if (dm_snprintf(lockfile, sizeof(lockfile),
"%s/V_%s", _lock_dir, resource) < 0) {
log_error("Too long locking filename %s/V_%s.",
_lock_dir, resource);
return 0;
}
if (!lock_file(lockfile, flags))
return_0;
break;
case LCK_LV:
switch (flags & LCK_TYPE_MASK) {
case LCK_UNLOCK:
log_very_verbose("Unlocking LV %s%s%s", resource, origin_only ? " without snapshots" : "", revert ? " (reverting)" : "");
if (!lv_resume_if_active(cmd, resource, origin_only, 0, revert, lv_ondisk(lv)))
return 0;
break;
case LCK_NULL:
log_very_verbose("Locking LV %s (NL)", resource);
if (!lv_deactivate(cmd, resource, lv_ondisk(lv)))
return 0;
break;
case LCK_READ:
log_very_verbose("Locking LV %s (R)", resource);
if (!lv_activate_with_filter(cmd, resource, 0, lv->status & LV_NOSCAN ? 1 : 0,
lv->status & LV_TEMPORARY ? 1 : 0, lv_ondisk(lv)))
return 0;
break;
case LCK_PREAD:
log_very_verbose("Locking LV %s (PR) - ignored", resource);
break;
case LCK_WRITE:
log_very_verbose("Locking LV %s (W)%s", resource, origin_only ? " without snapshots" : "");
if (!lv_suspend_if_active(cmd, resource, origin_only, 0, lv_ondisk(lv), lv))
return 0;
break;
case LCK_EXCL:
log_very_verbose("Locking LV %s (EX)", resource);
if (!lv_activate_with_filter(cmd, resource, 1, lv->status & LV_NOSCAN ? 1 : 0,
lv->status & LV_TEMPORARY ? 1 : 0, lv_ondisk(lv)))
return 0;
break;
default:
break;
}
break;
default:
log_error("Unrecognised lock scope: %d",
flags & LCK_SCOPE_MASK);
return 0;
}
return 1;
}
int init_file_locking(struct locking_type *locking, struct cmd_context *cmd,
int suppress_messages)
{
int r;
const char *locking_dir;
init_flock(cmd);
locking->lock_resource = _file_lock_resource;
locking->reset_locking = _reset_file_locking;
locking->fin_locking = _fin_file_locking;
locking->flags = 0;
/* Get lockfile directory from config file */
locking_dir = find_config_tree_str(cmd, global_locking_dir_CFG, NULL);
if (strlen(locking_dir) >= sizeof(_lock_dir)) {
log_error("Path for locking_dir %s is invalid.", locking_dir);
return 0;
}
strcpy(_lock_dir, locking_dir);
(void) dm_prepare_selinux_context(_lock_dir, S_IFDIR);
r = dm_create_dir(_lock_dir);
(void) dm_prepare_selinux_context(NULL, 0);
if (!r)
return 0;
/* Trap a read-only file system */
if ((access(_lock_dir, R_OK | W_OK | X_OK) == -1) && (errno == EROFS))
return 0;
return 1;
}
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