mirror of
git://sourceware.org/git/lvm2.git
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328 lines
6.5 KiB
C
328 lines
6.5 KiB
C
/*
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* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
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* Copyright (C) 2004 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 General Public License v.2.
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*
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* You should have received a copy of the GNU 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 "toolcontext.h"
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#include "memlock.h"
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#include <signal.h>
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#include <sys/stat.h>
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#include <limits.h>
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#include <unistd.h>
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static struct locking_type _locking;
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static sigset_t _oldset;
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static int _vg_lock_count = 0; /* Number of locks held */
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static int _vg_write_lock_held = 0; /* VG write lock held? */
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static int _signals_blocked = 0;
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static void _block_signals(int flags)
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{
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sigset_t set;
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if (_signals_blocked)
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return;
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if (sigfillset(&set)) {
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log_sys_error("sigfillset", "_block_signals");
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return;
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}
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if (sigprocmask(SIG_SETMASK, &set, &_oldset)) {
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log_sys_error("sigprocmask", "_block_signals");
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return;
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}
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_signals_blocked = 1;
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return;
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}
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static void _unblock_signals(void)
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{
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/* Don't unblock signals while any locks are held */
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if (!_signals_blocked || _vg_lock_count)
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return;
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if (sigprocmask(SIG_SETMASK, &_oldset, NULL)) {
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log_sys_error("sigprocmask", "_block_signals");
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return;
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}
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_signals_blocked = 0;
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return;
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}
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static void _lock_memory(int flags)
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{
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if (!(_locking.flags & LCK_PRE_MEMLOCK))
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return;
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if ((flags & (LCK_SCOPE_MASK | LCK_TYPE_MASK)) == LCK_LV_SUSPEND)
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memlock_inc();
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}
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static void _unlock_memory(int flags)
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{
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if (!(_locking.flags & LCK_PRE_MEMLOCK))
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return;
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if ((flags & (LCK_SCOPE_MASK | LCK_TYPE_MASK)) == LCK_LV_RESUME)
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memlock_dec();
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}
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void reset_locking(void)
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{
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int was_locked = _vg_lock_count;
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_vg_lock_count = 0;
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_vg_write_lock_held = 0;
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_locking.reset_locking();
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if (was_locked)
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_unblock_signals();
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}
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static inline void _update_vg_lock_count(int flags)
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{
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if ((flags & LCK_SCOPE_MASK) != LCK_VG)
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return;
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if ((flags & LCK_TYPE_MASK) == LCK_UNLOCK)
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_vg_lock_count--;
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else
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_vg_lock_count++;
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/* We don't bother to reset this until all VG locks are dropped */
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if ((flags & LCK_TYPE_MASK) == LCK_WRITE)
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_vg_write_lock_held = 1;
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else if (!_vg_lock_count)
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_vg_write_lock_held = 0;
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}
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/*
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* Select a locking type
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*/
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int init_locking(int type, struct config_tree *cft)
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{
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init_lockingfailed(0);
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switch (type) {
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case 0:
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init_no_locking(&_locking, cft);
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log_print("WARNING: Locking disabled. Be careful! "
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"This could corrupt your metadata.");
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return 1;
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case 1:
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if (!init_file_locking(&_locking, cft))
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break;
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log_very_verbose("File-based locking enabled.");
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return 1;
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#ifdef HAVE_LIBDL
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case 2:
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if (!init_external_locking(&_locking, cft))
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break;
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log_very_verbose("External locking enabled.");
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return 1;
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#endif
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#ifdef CLUSTER_LOCKING_INTERNAL
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case 3:
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if (!init_cluster_locking(&_locking, cft))
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break;
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log_very_verbose("Cluster locking enabled.");
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return 1;
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#endif
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default:
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log_error("Unknown locking type requested.");
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return 0;
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}
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if (!ignorelockingfailure())
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return 0;
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/* FIXME Ensure only read ops are permitted */
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log_verbose("Locking disabled - only read operations permitted.");
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init_no_locking(&_locking, cft);
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init_lockingfailed(1);
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return 1;
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}
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void fin_locking(void)
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{
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_locking.fin_locking();
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}
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/*
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* Does the LVM1 driver know of this VG name?
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*/
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int check_lvm1_vg_inactive(struct cmd_context *cmd, const char *vgname)
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{
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struct stat info;
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char path[PATH_MAX];
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/* We'll allow operations on orphans */
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if (!*vgname)
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return 1;
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if (lvm_snprintf(path, sizeof(path), "%s/lvm/VGs/%s", cmd->proc_dir,
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vgname) < 0) {
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log_error("LVM1 proc VG pathname too long for %s", vgname);
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return 0;
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}
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if (stat(path, &info) == 0) {
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log_error("%s exists: Is the original LVM driver using "
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"this volume group?", path);
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return 0;
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} else if (errno != ENOENT && errno != ENOTDIR) {
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log_sys_error("stat", path);
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return 0;
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}
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return 1;
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}
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/*
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* VG locking is by VG name.
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* FIXME This should become VG uuid.
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*/
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static int _lock_vol(struct cmd_context *cmd, const char *resource, int flags)
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{
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_block_signals(flags);
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_lock_memory(flags);
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if (!(_locking.lock_resource(cmd, resource, flags))) {
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_unlock_memory(flags);
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_unblock_signals();
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return 0;
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}
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_update_vg_lock_count(flags);
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_unlock_memory(flags);
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_unblock_signals();
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return 1;
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}
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int lock_vol(struct cmd_context *cmd, const char *vol, int flags)
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{
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char resource[258];
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switch (flags & LCK_SCOPE_MASK) {
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case LCK_VG:
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/* Lock VG to change on-disk metadata. */
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/* If LVM1 driver knows about the VG, it can't be accessed. */
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if (!check_lvm1_vg_inactive(cmd, vol))
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return 0;
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case LCK_LV:
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/* Suspend LV if it's active. */
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strncpy(resource, vol, sizeof(resource));
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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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if (!_lock_vol(cmd, resource, flags))
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return 0;
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/* Perform immediate unlock unless LCK_HOLD set */
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if (!(flags & LCK_HOLD) && ((flags & LCK_TYPE_MASK) != LCK_UNLOCK)) {
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if (!_lock_vol(cmd, resource,
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(flags & ~LCK_TYPE_MASK) | LCK_UNLOCK))
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return 0;
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}
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return 1;
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}
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/* Unlock list of LVs */
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int resume_lvs(struct cmd_context *cmd, struct list *lvs)
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{
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struct lv_list *lvl;
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list_iterate_items(lvl, lvs)
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resume_lv(cmd, lvl->lv->lvid.s);
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return 1;
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}
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/* Lock a list of LVs */
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int suspend_lvs(struct cmd_context *cmd, struct list *lvs)
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{
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struct list *lvh;
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struct lv_list *lvl;
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list_iterate_items(lvl, lvs) {
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if (!suspend_lv(cmd, lvl->lv->lvid.s)) {
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log_error("Failed to suspend %s", lvl->lv->name);
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list_uniterate(lvh, lvs, &lvl->list) {
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lvl = list_item(lvh, struct lv_list);
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resume_lv(cmd, lvl->lv->lvid.s);
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}
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return 0;
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}
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}
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return 1;
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}
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/* Lock a list of LVs */
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int activate_lvs_excl(struct cmd_context *cmd, struct list *lvs)
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{
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struct list *lvh;
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struct lv_list *lvl;
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list_iterate_items(lvl, lvs) {
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if (!activate_lv_excl(cmd, lvl->lv->lvid.s)) {
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log_error("Failed to activate %s", lvl->lv->name);
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list_uniterate(lvh, lvs, &lvl->list) {
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lvl = list_item(lvh, struct lv_list);
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activate_lv(cmd, lvl->lv->lvid.s);
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}
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return 0;
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}
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}
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return 1;
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}
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int vg_write_lock_held(void)
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{
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return _vg_write_lock_held;
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}
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int locking_is_clustered(void)
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{
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return (_locking.flags & LCK_CLUSTERED) ? 1 : 0;
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}
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