Implement lock-override options without locking type

The options: --nolocking, --readonly, --sysinit
override, or make exceptions to, the normal file locking
behavior.  Implement these by just checking for the
options in the file locking path instead of using
special locking types.

lib/locking/file_locking.c

@@ -92,7 +92,7 @@ int init_file_locking(struct locking_type *locking, struct cmd_context *cmd,
 	locking->lock_resource = _file_lock_resource;
 	locking->reset_locking = _reset_file_locking;
 	locking->fin_locking = _fin_file_locking;
-	locking->flags = 0;
+	locking->flags = LCK_FLOCK;
 
 	/* Get lockfile directory from config file */
 	locking_dir = find_config_tree_str(cmd, global_locking_dir_CFG, NULL);

lib/locking/locking.c

@@ -34,6 +34,8 @@ static struct locking_type _locking;
 static int _vg_lock_count = 0;		/* Number of locks held */
 static int _vg_write_lock_held = 0;	/* VG write lock held? */
 static int _blocking_supported = 0;
+static int _file_locking_readonly = 0;
+static int _file_locking_sysinit = 0;
 
 static void _unblock_signals(void)
 {
@@ -46,6 +48,10 @@ void reset_locking(void)
 {
 	int was_locked = _vg_lock_count;
 
+	/* file locking disabled */
+	if (!_locking.flags)
+		return;
+
 	_vg_lock_count = 0;
 	_vg_write_lock_held = 0;
 
@@ -82,21 +88,19 @@ static void _update_vg_lock_count(const char *resource, uint32_t flags)
  * Select a locking type
  * type: locking type; if < 0, then read config tree value
  */
-int init_locking(int type, struct cmd_context *cmd, int suppress_messages)
+int init_locking(struct cmd_context *cmd, int file_locking_sysinit, int file_locking_readonly)
 {
+	int suppress_messages = 0;
+
 	if (getenv("LVM_SUPPRESS_LOCKING_FAILURE_MESSAGES"))
 		suppress_messages = 1;
 
-	if (type < 0)
-		type = find_config_tree_int(cmd, global_locking_type_CFG, NULL);
+	if (file_locking_sysinit)
+		suppress_messages = 1;
 
 	_blocking_supported = find_config_tree_bool(cmd, global_wait_for_locks_CFG, NULL);
-
-	if (type != 1)
-		log_warn("WARNING: locking_type deprecated, using file locking.");
-
-	if (type == 3)
-		log_warn("WARNING: See lvmlockd(8) for information on using cluster/clvm VGs.");
+	_file_locking_readonly = file_locking_readonly;
+	_file_locking_sysinit = file_locking_sysinit;
 
 	log_very_verbose("%sFile-based locking selected.", _blocking_supported ? "" : "Non-blocking ");
 
@@ -108,6 +112,10 @@ int init_locking(int type, struct cmd_context *cmd, int suppress_messages)
 
 void fin_locking(void)
 {
+	/* file locking disabled */
+	if (!_locking.flags)
+		return;
+
 	_locking.fin_locking();
 }
 
@@ -135,10 +143,30 @@ static int _lock_vol(struct cmd_context *cmd, const char *resource, uint32_t fla
 		goto out;
 	}
 
-	if (cmd->metadata_read_only && lck_type == LCK_WRITE &&
+	if ((lck_type == LCK_WRITE) && (lck_scope == LCK_VG) && !(flags & LCK_CACHE) &&
 	    strcmp(resource, VG_GLOBAL)) {
-		log_error("Operation prohibited while global/metadata_read_only is set.");
-		goto out;
+
+		/* read only locking set in lvm.conf metadata_read_only */
+
+		if (cmd->metadata_read_only) {
+			log_error("Operation prohibited while global/metadata_read_only is set.");
+			goto out;
+		}
+
+		/* read only locking set with option --readonly */
+
+		if (_file_locking_readonly) {
+			log_error("Read-only locking specified. Write locks are prohibited.");
+			goto out;
+		}
+
+		/* read only locking (except activation) set with option --sysinit */
+		/* FIXME: sysinit is intended to allow activation, add that exception here */
+
+		if (_file_locking_sysinit) {
+			log_error("Read-only sysinit locking specified. Write locks are prohibited.");
+			goto out;
+		}
 	}
 
 	if ((ret = _locking.lock_resource(cmd, resource, flags, NULL))) {
@@ -169,6 +197,10 @@ int lock_vol(struct cmd_context *cmd, const char *vol, uint32_t flags, const str
 	char resource[258] __attribute__((aligned(8)));
 	int lck_type = flags & LCK_TYPE_MASK;
 
+	/* file locking disabled */
+	if (!_locking.flags)
+		return 1;
+
 	if (flags == LCK_NONE) {
 		log_debug_locking(INTERNAL_ERROR "%s: LCK_NONE lock requested", vol);
 		return 1;
@@ -240,7 +272,7 @@ int vg_write_lock_held(void)
 
 int locking_is_clustered(void)
 {
-	return (_locking.flags & LCK_CLUSTERED) ? 1 : 0;
+	return 0;
 }
 
 int sync_local_dev_names(struct cmd_context* cmd)

lib/locking/locking.h

@@ -21,7 +21,7 @@
 
 struct logical_volume;
 
-int init_locking(int type, struct cmd_context *cmd, int suppress_messages);
+int init_locking(struct cmd_context *cmd, int suppress_messages, int only_read_locks);
 void fin_locking(void);
 void reset_locking(void);
 int vg_write_lock_held(void);

lib/locking/locking_types.h

@@ -23,12 +23,10 @@ typedef int (*query_resource_fn) (const char *resource, const char *node, int *m
 typedef void (*fin_lock_fn) (void);
 typedef void (*reset_lock_fn) (void);
 
-#define LCK_PRE_MEMLOCK			0x00000001	/* Is memlock() needed before calls? */
-#define LCK_CLUSTERED			0x00000002
-#define LCK_SUPPORTS_REMOTE_QUERIES	0x00000004
+#define LCK_FLOCK			0x00000001
 
 struct locking_type {
-	uint32_t flags;
+	uint32_t flags;   /* 0 means file locking is disabled */
 	lock_resource_fn lock_resource;
 	query_resource_fn query_resource;
 
@@ -36,17 +34,5 @@ struct locking_type {
 	fin_lock_fn fin_locking;
 };
 
-/*
- * Locking types
- */
-void init_no_locking(struct locking_type *locking, struct cmd_context *cmd,
-		     int suppress_messages);
-
-void init_dummy_locking(struct locking_type *locking, struct cmd_context *cmd,
-			int suppress_messages);
-
-int init_readonly_locking(struct locking_type *locking, struct cmd_context *cmd,
-			  int suppress_messages);
-
 int init_file_locking(struct locking_type *locking, struct cmd_context *cmd,
 		      int suppress_messages);

tools/lvmcmdline.c

@@ -2734,6 +2734,9 @@ int lvm_run_command(struct cmd_context *cmd, int argc, char **argv)
 	const char *reason = NULL;
 	int ret = 0;
 	int locking_type;
+	int file_locking_disable = 0;
+	int file_locking_sysinit = 0;
+	int file_locking_readonly = 0;
 	int monitoring;
 	char *arg_new, *arg;
 	int i;
@@ -2908,34 +2911,31 @@ int lvm_run_command(struct cmd_context *cmd, int argc, char **argv)
 		goto out;
 	}
 
-	if (_cmd_no_meta_proc(cmd))
-		locking_type = 0;
-	else if (arg_is_set(cmd, readonly_ARG)) {
-		if (find_config_tree_bool(cmd, global_use_lvmlockd_CFG, NULL)) {
-			/*
-			 * FIXME: we could use locking_type 5 here if that didn't
-			 * cause CLUSTERED to be set, which conflicts with using lvmlockd.
-			 */
-			locking_type = 1;
-			cmd->lockd_gl_disable = 1;
-			cmd->lockd_vg_disable = 1;
-			cmd->lockd_lv_disable = 1;
-		} else {
-			locking_type = 5;
-		}
+	if (arg_is_set(cmd, nolocking_ARG) || _cmd_no_meta_proc(cmd))
+		file_locking_disable = 1;
 
-		if (lvmetad_used()) {
-			lvmetad_make_unused(cmd);
-			log_verbose("Not using lvmetad because read-only is set.");
-		}
-	} else if (arg_is_set(cmd, nolocking_ARG))
-		locking_type = 0;
-	else
-		locking_type = -1;
+	else if (arg_is_set(cmd, sysinit_ARG))
+		file_locking_sysinit = 1;
 
-	if (!init_locking(locking_type, cmd, _cmd_no_meta_proc(cmd) || arg_is_set(cmd, sysinit_ARG))) {
-		ret = ECMD_FAILED;
-		goto_out;
+	else if (arg_is_set(cmd, readonly_ARG))
+		file_locking_readonly = 1;
+
+	locking_type = find_config_tree_int(cmd, global_locking_type_CFG, NULL);
+
+	if (locking_type == 3)
+		log_warn("WARNING: See lvmlockd(8) for information on using cluster/clvm VGs.");
+
+	if (locking_type != 1) {
+		log_warn("WARNING: locking_type deprecated, using file locking.");
+		locking_type = 1;
+	}
+
+	if (!file_locking_disable) {
+		/* Set up file locking */
+		if (!init_locking(cmd, file_locking_sysinit, file_locking_readonly)) {
+			ret = ECMD_FAILED;
+			goto_out;
+		}
 	}
 
 	if (!_cmd_no_meta_proc(cmd) && !_init_lvmlockd(cmd)) {