thin-provisioning-tools/caching/cache_metadata_size.cc

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#include "version.h"
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#include "caching/commands.h"
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#include <boost/lexical_cast.hpp>
#include <boost/optional.hpp>
#include <iostream>
#include <getopt.h>
#include <stdint.h>
#include <stdexcept>
using namespace std;
//----------------------------------------------------------------
namespace {
struct flags {
flags()
: max_hint_width(4) {
// Dance around some spurious compiler warnings
device_size = 0;
block_size = 0;
nr_blocks = 0;
device_size.reset();
block_size.reset();
nr_blocks.reset();
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}
boost::optional<uint64_t> device_size;
boost::optional<uint32_t> block_size;
boost::optional<uint64_t> nr_blocks;
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uint32_t max_hint_width;
};
void usage(ostream &out, string const &cmd) {
out << "Usage: " << cmd << " [options]" << endl
<< "Options:" << endl
<< " {-h|--help}" << endl
<< " {-V|--version}" << endl
<< " {--block-size <sectors>}" << endl
<< " {--device-size <sectors>}" << endl
<< " {--nr-blocks <natural>}" << endl << endl
<< "These all relate to the size of the fast device (eg, SSD), rather" << endl
<< "than the whole cached device." << endl;
}
enum parse_result {
FINISH,
CONTINUE
};
parse_result parse_command_line(string const &prog_name, int argc, char **argv, flags &fs) {
int c;
char const short_opts[] = "hV";
option const long_opts[] = {
{ "block-size", required_argument, NULL, 0 },
{ "device-size", required_argument, NULL, 1 },
{ "nr-blocks", required_argument, NULL, 2 },
{ "max-hint-width", required_argument, NULL, 3 },
{ "help", no_argument, NULL, 'h' },
{ "version", no_argument, NULL, 'V' },
{ NULL, no_argument, NULL, 0 }
};
while ((c = getopt_long(argc, argv, short_opts, long_opts, NULL)) != -1) {
switch (c) {
case 0:
fs.block_size = boost::lexical_cast<uint32_t>(optarg);
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break;
case 1:
fs.device_size = boost::lexical_cast<uint64_t>(optarg);
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break;
case 2:
fs.nr_blocks = boost::lexical_cast<uint64_t>(optarg);
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break;
case 3:
fs.max_hint_width = boost::lexical_cast<uint32_t>(optarg);
break;
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case 'h':
usage(cout, prog_name);
return FINISH;
break;
case 'V':
cout << THIN_PROVISIONING_TOOLS_VERSION << endl;
return FINISH;
break;
default:
usage(cerr, prog_name);
throw runtime_error("Invalid command line");
break;
}
}
return CONTINUE;
}
uint64_t get_nr_blocks(flags &fs) {
if (fs.device_size) {
if (!fs.block_size)
throw runtime_error("If you specify --device-size you must also give --block-size.");
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uint64_t nr_blocks = *fs.device_size / *fs.block_size;
if (fs.nr_blocks) {
if (nr_blocks != *fs.nr_blocks)
throw runtime_error(
"Contradictory arguments given, --nr-blocks doesn't match the --device-size and --block-size.");
}
return nr_blocks;
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}
if (fs.block_size && !fs.device_size)
throw runtime_error("If you specify --block-size you must also give --device-size.");
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if (fs.nr_blocks)
return *fs.nr_blocks;
throw runtime_error("Please specify either --device-size and --block-size, or --nr-blocks.");
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}
uint64_t meg(uint64_t n) {
return n * 2048;
}
uint64_t calc_size(uint64_t nr_blocks, uint32_t max_hint_width) {
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uint64_t const SECTOR_SIZE = 512;
uint64_t const TRANSACTION_OVERHEAD = meg(4);
uint64_t const BYTES_PER_BLOCK = 16;
uint64_t const HINT_OVERHEAD_PER_BLOCK = 8;
uint64_t mapping_size = (nr_blocks * BYTES_PER_BLOCK) / SECTOR_SIZE;
uint64_t hint_size = (nr_blocks * (max_hint_width + HINT_OVERHEAD_PER_BLOCK)) / SECTOR_SIZE;
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return TRANSACTION_OVERHEAD + mapping_size + hint_size;
}
}
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int cache_metadata_size_main(int argc, char **argv)
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{
flags fs;
try {
switch (parse_command_line(argv[0], argc, argv, fs)) {
case FINISH:
return 0;
case CONTINUE:
break;
}
uint64_t nr_blocks = get_nr_blocks(fs);
cout << calc_size(nr_blocks, fs.max_hint_width) << " sectors" << endl;
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} catch (std::exception const &e) {
cerr << e.what();
return 1;
}
return 0;
}
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base::command caching::cache_metadata_size_cmd("cache_metadata_size", cache_metadata_size_main);
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//----------------------------------------------------------------