thin_metadata_size.c: new C implementation of metadata size calculation tool

thin-provisioning/thin_metadata_size.c

@@ -0,0 +1,209 @@
+/*
+ * Copyright (C) 2013 Red Hat, GmbH
+ * 
+ * This file is released under the GPL
+ *
+ *
+ * Calculates device-mapper thin privisioning
+ * metadata device size based on pool, block size and
+ * maximum expected thin provisioned devices and snapshots.
+ *
+ */
+
+#include <getopt.h>
+#include <libgen.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/*----------------------------------------------------------------*/
+
+static char *prg;
+
+enum numeric_options { blocksize, poolsize, maxthins, numeric, opt_end};
+struct global {
+	#define UNIT_ARRAY_SZ	18
+	struct {
+		char *chars;
+		char *strings[UNIT_ARRAY_SZ];
+		unsigned long long factors[UNIT_ARRAY_SZ];
+	} unit;
+
+	struct options {
+		unsigned long long n[opt_end];
+		char unit;
+	} options;
+};
+#define bytes_per_sector g->unit.factors[1]
+
+static struct global *init(void)
+{
+	unsigned u;
+	static struct global r;
+	static char *unit_strings[] = { "bytes", "sectors",
+					"kilobytes", "kibibytes", "megabytes",  "mebibytes",
+					"gigabytes", "gibibytes", "terabytes",  "tebibytes",
+					"petabytes", "pebibytes", "exabytes",   "ebibytes",
+					"zetabytes", "zebibytes", "yottabytes", "yobibytes" };
+
+	memset(&r, 0, sizeof(r));
+	r.unit.chars = "bskKmMgGtTpPeEzZyY";
+	u = 0;
+	r.unit.factors[u++] = 1;
+	r.unit.factors[u++] = 512;
+	r.unit.factors[u++] = 1024;
+	r.unit.factors[u++] = 1000;
+	for ( ; u < UNIT_ARRAY_SZ; u += 2) {
+		r.unit.factors[u] = r.unit.factors[2] * r.unit.factors[u - 2];
+		r.unit.factors[u+1] = r.unit.factors[3] * r.unit.factors[u - 1];
+	}
+
+	u = UNIT_ARRAY_SZ;
+	while (u--)
+		r.unit.strings[u] = unit_strings[u];
+
+	r.options.unit = 's';
+
+	return &r;
+}
+
+static unsigned get_index(struct global *g, char unit_char)
+{
+	char *o = strchr(g->unit.chars, unit_char);
+
+	return o ? o - g->unit.chars : 1;
+}
+
+static void abort_prg(const char *msg)
+{
+	fprintf(stderr, "%s - %s\n", prg, msg);
+	exit(1);
+}
+
+static void check_opts(struct options *options)
+{
+	if (!options->n[blocksize] || !options->n[poolsize] || !options->n[maxthins])
+		abort_prg("3 arguments required!");
+	else if (options->n[blocksize] & (options->n[blocksize] - 1))
+  		abort_prg("block size must be 2^^N");
+	else if (options->n[poolsize] < options->n[blocksize])
+  		abort_prg("poolsize must be much larger than blocksize");
+	else if (!options->n[maxthins])
+		abort_prg("maximum number of thin provisioned devices must be > 0");
+}
+
+static unsigned long long to_bytes(struct global *g, char *sz, int div)
+{
+	unsigned len = strlen(sz);
+	char uc = 's', *us = strchr(g->unit.chars, sz[len-1]);
+
+	if (us)
+		uc = sz[len-1], sz[len-1] = 0;
+
+	return g->unit.factors[get_index(g, uc)] * atoll(sz) / (div ? bytes_per_sector : 1);
+}
+
+static void printf_aligned(struct global *g, char *a, char *b, char *c, int units)
+{
+	char buf[80];
+
+	strcpy(buf, b);
+	if (units)
+		strcat(buf, "["), strcat(buf, g->unit.chars), strcat(buf, "]");
+
+	printf("\t%-4s%-45s%s\n", a, buf, c);
+}
+
+static void help(struct global *g)
+{
+	printf ("Thin Provisioning Metadata Device Size Calculator.\nUsage: %s [opts]\n", prg);
+	printf_aligned(g, "-b", "--block-size BLOCKSIZE", "Block size of thin provisioned devices.", 1);
+	printf_aligned(g, "-s", "--pool-size SIZE", "Size of pool device.", 1);
+	printf_aligned(g, "-m", "--max-thins #MAXTHINS", "Maximum sum of all thin devices and snapshots.", 0);
+	printf_aligned(g, "-u", "--unit ", "Output unit specifier.", 1);
+	printf_aligned(g, "-n", "--numeric-only", "Output numeric value only.", 0);
+	printf_aligned(g, "-h", "--help", "This help.", 0);
+	exit(0);
+}
+
+static struct global *parse_command_line(struct global *g, int argc, char **argv)
+{
+	int c;
+	static struct option long_options[] = {
+		{"block-size",	required_argument, 0,  'b' },
+		{"pool-size",	required_argument, 0,  's' },
+		{"max-thins",	required_argument, 0,  'm' },
+		{"unit",	required_argument, 0,  'u' },
+		{"numeric-only",required_argument, 0,  'n' },
+		{"help",	no_argument,       0,  'h' },
+		{NULL,		0,		   0,  0 }
+	};
+
+	while ((c = getopt_long(argc, argv, "b:s:m:u:nh", long_options, NULL)) != -1) {
+		if (c == 'b')
+      			g->options.n[blocksize] = to_bytes(g, optarg, 1);
+		else if (c == 's')
+      			g->options.n[poolsize] = to_bytes(g, optarg, 1);
+		else if (c == 'm')
+      			g->options.n[maxthins] = to_bytes(g, optarg, 0);
+		else if (c == 'u') {
+			if (*(optarg + 1))
+				abort_prg("only one unit specifier allowed!");
+			else if (!strchr(g->unit.chars, *optarg))
+				abort_prg("output unit specifier invalid!");
+
+      			g->options.unit = *optarg;
+		} else if (c == 'n')
+			g->options.n[numeric] = 1;
+		else if (c == 'h')
+			help(g);
+		else
+			abort_prg("Invalid option!");
+	}
+
+	check_opts(&g->options);
+
+	return 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 unsigned precision(double r)
+{
+	return r == truncl(r) ? 0 : 3;
+}
+
+static void estimated_result(struct global *g)
+{
+	unsigned idx = get_index(g, g->options.unit);
+	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])) * 8 * bytes_per_sector; /* in bytes! */
+	r /= g->unit.factors[idx]; /* in requested unit */
+
+// printf("%c idx=%u factor=%llu r=%f\n", g->options.unit, idx, g->unit.factors[idx], r);
+
+	/* FIXME: correct output */
+	if (g->options.n[numeric])
+		printf("%.*f\n", precision(r), r);
+	else
+		printf("%s - estimated metadata area size is %.*f %s\n", prg, precision(r), r, g->unit.strings[idx]);
+}
+
+int main(int argc, char **argv)
+{
+	prg = basename(*argv);
+	estimated_result(parse_command_line(init(), argc, argv));
+	return 0;
+}