diff --git a/Makefile.in b/Makefile.in

index a82ff67..1e7bd54 100644

--- a/Makefile.in

+++ b/Makefile.in

@@ -24,7 +24,8 @@ PROGRAMS=\

 	thin_dump \

 	thin_restore \

 	thin_repair \

-	thin_rmap

+	thin_rmap \

+	thin_metadata_size

 all: $(PROGRAMS)

@@ -64,7 +65,7 @@ SOURCE=\

 PDATA_OBJECTS=$(subst .cc,.o,$(SOURCE))

-PROGRAM_SOURCE=\

+CXX_PROGRAM_SOURCE=\

 	cache/check.cc \

 	\

 	thin-provisioning/thin_check.cc \

@@ -73,10 +74,15 @@ PROGRAM_SOURCE=\

 	thin-provisioning/thin_repair.cc \

 	thin-provisioning/thin_rmap.cc

+C_PROGRAM_SOURCE=\

+	thin-provisioning/thin_metadata_size.c

+

+CC:=@CC@

 CXX:=@CXX@

 OBJECTS:=$(subst .cc,.o,$(SOURCE))

 TOP_DIR:=@top_srcdir@

 TOP_BUILDDIR:=@top_builddir@

+CFLAGS+=-g -Wall -O3

 CXXFLAGS+=-std=c++11 -g -Wall -fno-strict-aliasing

 CXXFLAGS+=@CXXOPTIMISE_FLAG@

 CXXFLAGS+=@CXXDEBUG_FLAG@

@@ -104,6 +110,14 @@ endif

 .SUFFIXES: .d

+%.o: %.c

+	@echo "    [CC] $<"

+	$(V) $(CC) -c $(INCLUDES) $(CFLAGS) -o $@ $<

+	@echo "    [DEP] $<"

+	$(V) $(CC) -MM -MT $(subst .c,.o,$<) $(INCLUDES) $(CFLAGS) $< > $*.$$$$; \

+	sed 's,\([^ :]*\)\.o[ :]*,\1.o \1.gmo $* : Makefile ,g' < $*.$$$$ > $*.d; \

+	$(RM) $*.$$$$

+

 %.o: %.cc

 	@echo "    [CXX] $<"

 	$(V) $(CXX) -c $(INCLUDES) $(CXXFLAGS) -o $@ $<

@@ -195,6 +209,10 @@ thin_rmap: $(THIN_RMAP_OBJECTS) thin-provisioning/thin_rmap.o

 	@echo "    [LD]  $@"

 	$(V) $(CXX) $(CXXFLAGS) -o $@ $+ $(LIBS)

+thin_metadata_size: thin-provisioning/thin_metadata_size.o

+	@echo "    [LD]  $@"

+	$(V) $(CC) $(CFLAGS) -o $@ $+ -lm

+

 #----------------------------------------------------------------

 # Cache tools

@@ -221,29 +239,33 @@ cache_check: $(CACHE_CHECK_OBJECTS) cache/check.o

 DEPEND_FILES=\

 	$(subst .cc,.d,$(SOURCE)) \

 	$(subst .cc,.d,$(TEST_SOURCE)) \

-	$(subst .cc,.d,$(PROGRAM_SOURCE))

+	$(subst .cc,.d,$(CXX_PROGRAM_SOURCE)) \

+	$(subst .c,.d,$(C_PROGRAM_SOURCE))

 .PHONY: clean distclean

 clean:

 	find . -name \*.o -delete

 	find . -name \*.gmo -delete

-	$(RM) $(DEPEND_FILES) $(TEST_PROGRAMS) $(PROGRAMS) $(GMOCK_OBJECTS) lib/*.a

+	find . -name \*.d -delete

+	$(RM) $(TEST_PROGRAMS) $(PROGRAMS) $(GMOCK_OBJECTS) lib/*.a

 distclean: clean

 	$(RM) config.cache config.log config.status configure.h version.h Makefile unit-tests/Makefile

 install: $(PROGRAMS)

 	$(INSTALL_DIR) $(BINDIR)

-	$(INSTALL_PROGRAM) thin_check $(BINDIR)

-	$(INSTALL_PROGRAM) thin_dump $(BINDIR)

-	$(INSTALL_PROGRAM) thin_repair $(BINDIR)

-	$(INSTALL_PROGRAM) thin_restore $(BINDIR)

-	$(INSTALL_PROGRAM) thin_rmap $(BINDIR)

+	$(INSTALL_PROGRAM) thin_check $(BINDIR)

+	$(INSTALL_PROGRAM) thin_dump $(BINDIR)

+	$(INSTALL_PROGRAM) thin_repair $(BINDIR)

+	$(INSTALL_PROGRAM) thin_restore $(BINDIR)

+	$(INSTALL_PROGRAM) thin_rmap $(BINDIR)

+	$(INSTALL_PROGRAM) thin_metadata_size $(BINDIR)

 	$(INSTALL_DIR) $(MANPATH)/man8

 	$(INSTALL_DATA) man8/thin_check.8 $(MANPATH)/man8

 	$(INSTALL_DATA) man8/thin_dump.8 $(MANPATH)/man8

 	$(INSTALL_DATA) man8/thin_restore.8 $(MANPATH)/man8

+

 .PHONY: install

 ifeq ("@TESTING@", "yes")

diff --git a/configure.in b/configure.in

index 78d88c1..8f25002 100644

--- a/configure.in

+++ b/configure.in

@@ -30,6 +30,7 @@ dnl -- Setup the directory where autoconf has auxilary files

 AC_CONFIG_AUX_DIR(autoconf)

 AC_CANONICAL_TARGET([])

 AC_PROG_CXX([g++])

+AC_PROG_CC([gcc])

 AC_LANG(C++)

 ################################################################

diff --git a/thin-provisioning/thin_metadata_size.c b/thin-provisioning/thin_metadata_size.c

new file mode 100755

index 0000000..1f52d51

--- /dev/null

+++ b/thin-provisioning/thin_metadata_size.c

@@ -0,0 +1,370 @@

+/*

+ * Copyright (C) 2013 Red Hat, GmbH

+ * 

+ * Calculates device-mapper thin privisioning

+ * metadata device size based on pool, block size and

+ * maximum expected thin provisioned devices and snapshots.

+ *

+ * This file is part of the thin-provisioning-tools source.

+ *

+ * thin-provisioning-tools is free software: you can redistribute it

+ * and/or modify it under the terms of the GNU General Public License

+ * as published by the Free Software Foundation, either version 3 of

+ * the License, or (at your option) any later version.

+ *

+ * thin-provisioning-tools is distributed in the hope that it will be

+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty

+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+ * GNU General Public License for more details.

+ *

+ * You should have received a copy of the GNU General Public License along

+ * with thin-provisioning-tools.  If not, see

+ * <http://www.gnu.org/licenses/>.

+ *

+ */

+

+#include <getopt.h>

+#include <libgen.h>

+#include <math.h>

+#include <stdio.h>

+#include <stdlib.h>

+#include <string.h>

+#include "version.h"

+

+#include <search.h>

+

+/*----------------------------------------------------------------*/

+

+enum numeric_options { BLOCKSIZE, POOLSIZE, MAXTHINS, NUMERIC, OPT_END};

+enum return_units { RETURN_BYTES, RETURN_SECTORS };

+enum numeric_type { NO_NUMBER, NUMBER, NUMBER_SHORT, NUMBER_LONG };

+typedef	unsigned bool;

+enum bool_value { false = 0, true = 1};

+struct global {

+	char *prg; /* program name */

+

+	/* Unit representations in characters, strings and numeric factors. */

+	struct {

+		char *chars;

+		char **strings;

+		unsigned long long *factors;

+	} unit;

+

+	/* Command line option properties. */

+	struct options {

+		unsigned unit_idx;

+		char *s[OPT_END];

+		unsigned long long n[OPT_END];

+	} options;

+};

+

+static void exit_prg(struct global *g, int ret)

+{

+	if (g) {

+		unsigned u = OPT_END;

+

+		while (u--) {

+			if (g->options.s[u])

+				free (g->options.s[u]);

+		}

+

+		free(g);

+	}

+

+	exit(ret);

+}

+

+static void abort_prg(struct global *g, const char *msg)

+{

+	fprintf(stderr, "%s - %s\n", g ? g->prg : "fatal", msg);

+	exit_prg(g, 1);

+}

+

+static int unit_index(struct global *g, char *unit_string)

+{

+	unsigned len;

+

+	if (!unit_string)

+		return unit_index(g, "sectors");

+

+	len = strlen(unit_string);

+	if (len == 1) {

+		char *o = strchr(g->unit.chars, *unit_string);

+

+		if (o)

+			return o - g->unit.chars;

+

+	} else {

+		char **s;

+

+		for (s = g->unit.strings; *s; s++)

+			if (!strncmp(*s, unit_string, len))

+				return s - g->unit.strings;

+	}

+

+	return -1;

+}

+

+#define ARRAY_SIZE(a) (sizeof(a)/sizeof(a[0]))

+static struct global *init_prg(char *prg_path)

+{

+	unsigned u;

+	static char *unit_chars = "bskKmMgGtTpPeEzZyY";

+	static char *unit_strings[] = { "bytes", "sectors",

+					"kilobytes", "kibibytes", "megabytes",  "mebibytes",

+					"gigabytes", "gibibytes", "terabytes",  "tebibytes",

+					"petabytes", "pebibytes", "exabytes",   "ebibytes",

+					"zetabytes", "zebibytes", "yottabytes", "yobibytes", NULL };

+	static unsigned long long unit_factors[ARRAY_SIZE(unit_strings) - 1] = { 1, 512, 1024, 1000 };

+	struct global *r = malloc(sizeof(*r));

+

+	if (!r)

+		abort_prg(r, "failed to allocate global context!");

+

+	memset(r, 0, sizeof(*r));

+

+	for (u = 4; unit_strings[u]; u += 2) {

+		unit_factors[u]   = unit_factors[u-2] * unit_factors[2];

+		unit_factors[u+1] = unit_factors[u-1] * unit_factors[3];

+	}

+

+	r->prg = basename(prg_path);

+	r->unit.chars = unit_chars;

+	r->unit.strings = unit_strings;

+	r->unit.factors = unit_factors;

+	r->options.unit_idx = unit_index(r, NULL);

+

+	return r;

+}

+

+static unsigned long long bytes_per_sector(struct global *g)

+{

+	return g->unit.factors[unit_index(g, "sectors")];

+}

+

+static void check_opts(struct global *g)

+{

+	struct options *o = &g->options;

+

+	if (!o->n[BLOCKSIZE])

+		abort_prg(g, "block size required!");

+	else if (!o->n[POOLSIZE])

+		abort_prg(g, "pool size required!");

+	else if (!o->n[MAXTHINS])

+		abort_prg(g, "max thins required!");

+	else if (o->n[BLOCKSIZE] & (o->n[BLOCKSIZE] - 1))

+  		abort_prg(g, "block size must be 2^^N");

+	else if (o->n[POOLSIZE] <= o->n[BLOCKSIZE])

+  		abort_prg(g, "pool size must be larger than block size");

+}

+

+static unsigned long long to_bytes(struct global *g, char *sz, enum return_units unit, int *index)

+{

+	int idx;

+	unsigned long long r;

+	char *us = sz;

+

+	/* Get pointer to unit identifier. */

+	us += strspn(sz, "0123456789");

+	if (*us) {

+		idx = unit_index(g, us);

+		if (idx < 0)

+			abort_prg(g, "Invalid unit specifier!");

+

+		*us = 0;

+		*index = idx;

+	} else {

+		idx = unit_index(g, NULL);

+		us = NULL;

+		*index = -1;

+	}

+

+	r = atoll(sz) * g->unit.factors[idx];

+	return (!us || unit == RETURN_SECTORS) ? r / bytes_per_sector(g) : r;

+}

+

+static void printf_aligned(struct global *g, char *a, char *b, char *c, bool units, bool mandatory)

+{

+	char buf[80];

+

+	strcpy(buf, b);

+	if (units)

+		strcat(buf, mandatory ? "{" :"["), strcat(buf, g->unit.chars), strcat(buf, mandatory ? "}" : "]");

+

+	printf("\t%-4s%-44s%s\n", a, buf, c);

+}

+

+static void help(struct global *g)

+{

+	printf ("Thin Provisioning Metadata Device Size Calculator.\nUsage: %s [options]\n", g->prg);

+	printf_aligned(g, "-b", "--block-size BLOCKSIZE", "Block size of thin provisioned devices.", true, false);

+	printf_aligned(g, "-s", "--pool-size SIZE", "Size of pool device.", true, false);

+	printf_aligned(g, "-m", "--max-thins #MAXTHINS", "Maximum sum of all thin devices and snapshots.", true, false);

+	printf_aligned(g, "-u", "--unit ", "Output unit specifier.", true, true);

+	printf_aligned(g, "-n", "--numeric-only [short|long]", "Output numeric value only (optionally with short/long unit identifier).", false, false);

+	printf_aligned(g, "-h", "--help", "This help.", false, false);

+	printf_aligned(g, "-V", "--version", "Print thin provisioning tools version.", false, false);

+	exit_prg(g, 0);

+}

+

+static void version(struct global *g)

+{

+	printf("%s\n", THIN_PROVISIONING_TOOLS_VERSION);

+	exit_prg(g, 1);

+}

+

+static void check_unit(struct global *g, char *arg)

+{

+	int idx = unit_index(g, arg);

+

+	if (idx < 0)

+		abort_prg(g, "output unit specifier invalid!");

+

+      	g->options.unit_idx = idx;

+}

+

+static void check_numeric_option(struct global *g, char *arg)

+{

+	if (g->options.n[NUMERIC] != NO_NUMBER)

+		abort_prg(g, "-n already given!");

+

+	g->options.n[NUMERIC] = NUMBER;

+

+	if (arg) {

+		bool unit_long = !strncmp("long", arg, strlen(arg));

+

+		if (!*arg || (strncmp("short", arg, strlen(arg)) && !unit_long))

+			abort_prg(g, "-n invalid option argument");

+

+		g->options.n[NUMERIC] = unit_long ? NUMBER_LONG : NUMBER_SHORT;

+	}

+}

+

+static void check_size(struct global *g, enum numeric_options o, char *arg)

+{

+	int idx;

+	bool valid_index = true;

+

+	if (g->options.n[o])

+		abort_prg(g, "option already given!");

+

+	g->options.n[o] = to_bytes(g, arg, o == MAXTHINS ? RETURN_BYTES : RETURN_SECTORS, &idx);

+	if (idx < 0) {

+		valid_index = false;

+		idx = g->options.unit_idx;

+	}

+

+	g->options.s[o] = malloc(strlen(arg) + strlen(g->unit.strings[idx]) + 1);

+	if (!g->options.s[o])

+		abort_prg(g, "failed to allocate string!");

+

+	strcpy(g->options.s[o], arg);

+	if (o != MAXTHINS || valid_index)

+		strcat(g->options.s[o], g->unit.strings[idx]);

+

+}

+

+static void parse_command_line(struct global *g, int argc, char **argv)

+{

+	int c;

+	static struct option long_options[] = {

+		{"block-size",	required_argument, NULL, 'b' },

+		{"pool-size",	required_argument, NULL, 's' },

+		{"max-thins",	required_argument, NULL, 'm' },

+		{"unit",	required_argument, NULL, 'u' },

+		{"numeric-only",optional_argument, NULL, 'n' },

+		{"help",	no_argument,       NULL, 'h' },

+		{"version",	no_argument,       NULL, 'V' },

+		{NULL,		0,		   NULL, 0   }

+	};

+

+	while ((c = getopt_long(argc, argv, "b:s:m:u:n::hV", long_options, NULL)) != -1) {

+		switch (c) {

+		case 'b':

+			check_size(g, BLOCKSIZE, optarg);

+			break;

+		case 's':

+			check_size(g, POOLSIZE, optarg);

+			break;

+		case 'm':

+			check_size(g, MAXTHINS, optarg);

+			break;

+		case 'u':

+			check_unit(g, optarg);

+			break;

+		case 'n':

+			check_numeric_option(g, optarg);

+			break;

+		case 'h':

+			help(g); /* exits */

+		case 'V':

+			version(g); /* exits */

+		default:

+			exit_prg(g, 1);

+		}

+	}

+

+	check_opts(g);

+}

+

+static const unsigned mappings_per_block(void)

+{

+	const struct {

+		const unsigned node;

+		const unsigned node_header;

+		const unsigned entry;

+	} btree_size = { 4096, 64, 16 };

+

+	return (btree_size.node - btree_size.node_header) / btree_size.entry;

+}

+

+static void print_precision(struct global *g, double r, unsigned idx)

+{

+	bool full = g->options.n[NUMERIC] == NO_NUMBER;

+	double rtrunc = truncl(r);

+

+	if (full)

+		printf("%s - ", g->prg);

+

+	if (r == rtrunc)

+		printf("%llu", (unsigned long long) r);

+	else

+		printf(r - rtrunc < 1E-2 ? "%0.2e" : "%0.2f", r);

+

+	if (full)

+		printf(" %s", g->unit.strings[idx]);

+	else if (g->options.n[NUMERIC] > NUMBER) {

+		if (g->options.n[NUMERIC] == NUMBER_SHORT)

+			printf("%c", g->unit.chars[idx]);

+		else

+			printf("%s", g->unit.strings[idx]);

+	}

+

+	if (full)

+		printf(" estimated metadata area size for \"--block-size=%s --pool-size=%s --max-thins=%s\"",

+		       g->options.s[BLOCKSIZE], g->options.s[POOLSIZE], g->options.s[MAXTHINS]);

+

+	putchar('\n');

+}

+

+static void print_estimated_result(struct global *g)

+{

+	double r;

+

+	/* double-fold # of nodes, because they aren't fully populated in average */

+	r = (1.0 + (2 * g->options.n[POOLSIZE] / g->options.n[BLOCKSIZE] / mappings_per_block() + g->options.n[MAXTHINS])); /* in 4k blocks */

+	r *=  8 * bytes_per_sector(g); /* in bytes! */

+	r /= g->unit.factors[g->options.unit_idx]; /* in requested unit */

+

+	print_precision(g, r, g->options.unit_idx);

+}

+

+int main(int argc, char **argv)

+{

+	struct global *g = init_prg(*argv);

+

+	parse_command_line(g, argc, argv);

+	print_estimated_result(g);

+	exit_prg(g, 0);

+	return 0; /* Doesn't get here... */

+}