/* * Copyright (C) 2001 Sistina Software (UK) Limited. * * This file is released under the LGPL. * */ #include "log.h" #include "locking.h" #include "locking_types.h" #include "lvm-string.h" #include "activate.h" #include <signal.h> static struct locking_type _locking; static int _lock_count = 0; /* Number of locks held */ static int _signals_ignored = 0; static void _ignore_signals(void) { int s; if (_signals_ignored) return; for (s = 0; s < NSIG; s++) signal(s, SIG_IGN); _signals_ignored = 1; return; } static void _enable_signals(void) { int s; /* Don't enable signals while any locks are held */ if (!_signals_ignored || _lock_count) return; for (s = 0; s < NSIG; s++) signal(s, SIG_DFL); _signals_ignored = 0; return; } static inline void _update_lock_count(int flags) { if ((flags & LCK_TYPE_MASK) == LCK_NONE) _lock_count--; else _lock_count++; } /* * No locking - currently does nothing. */ int no_lock_resource(const char *resource, int flags) { return 1; } void no_fin_locking(void) { return; } static void _init_no_locking(struct locking_type *locking, struct config_file *cf) { locking->lock_resource = no_lock_resource; locking->fin_locking = no_fin_locking; } /* * Select a locking type */ int init_locking(int type, struct config_file *cf) { switch (type) { case 0: _init_no_locking(&_locking, cf); log_print("WARNING: Locking disabled. Be carefui! " "This could corrupt your metadata."); break; case 1: if (!init_file_locking(&_locking, cf)) return 0; log_very_verbose("File-based locking enabled."); break; /****** case 2: if (!init_other_locking(&_locking, cf)) return 0; log_very_verbose("Other locking enabled."); break; ******/ default: log_error("Unknown locking type requested."); return 0; } return 1; } void fin_locking(void) { _locking.fin_locking(); } /* * VG locking is by name * LV locking is by struct logical_volume * FIXME This should take a unique name or id for an LV */ int lock_vol(const void *vol, int flags) { char resource[258]; switch (flags & LCK_SCOPE_MASK) { case LCK_VG: /* * Lock a volume group before changing on-disk metadata. */ strncpy(resource, (char *) vol, sizeof(resource)); break; case LCK_LV: /* * Suspends LV if it's active. */ default: log_error("Unrecognised lock scope: %d", flags & LCK_SCOPE_MASK); return 0; } _ignore_signals(); if (!(_locking.lock_resource(resource, flags))) { _enable_signals(); return 0; } _update_lock_count(flags); _enable_signals(); return 1; }