thin-provisioning-tools/thin-provisioning/thin_trim.cc
Joe Thornber 8e92158055 [thin_trim] first code drop.
No testing done as yet.
2014-11-18 16:03:03 +00:00

199 lines
4.3 KiB
C++

#include <iostream>
#include <getopt.h>
#include <sys/ioctl.h>
#include <linux/fs.h>
#undef BLOCK_SIZE
#include "thin-provisioning/commands.h"
#include "metadata.h"
#include "version.h"
using namespace persistent_data;
using namespace std;
using namespace thin_provisioning;
//----------------------------------------------------------------
namespace {
void confirm_pool_is_not_active() {
cout << "The pool must *not* be active when running this tool.\n"
<< "Do you wish to continue? [Y/N]\n"
<< endl;
string input;
cin >> input;
if (input != "Y")
exit(0);
}
class discard_emitter {
public:
discard_emitter(string const &data_dev, unsigned block_size, uint64_t nr_blocks)
: fd_(open_dev(data_dev, block_size * nr_blocks)),
block_size_(block_size) {
}
~discard_emitter() {
::close(fd_);
}
void emit(block_address b, block_address e) {
uint64_t range[2];
range[0] = block_to_byte(b);
range[1] = block_to_byte(e) - range[0];
if (ioctl(fd_, BLKDISCARD, &range))
throw runtime_error("discard ioctl failed");
}
private:
static int open_dev(string const &data_dev, uint64_t expected_size) {
int r, fd;
uint64_t blksize;
struct stat info;
fd = ::open(data_dev.c_str(), O_WRONLY);
if (fd < 0) {
ostringstream out;
out << "Couldn't open data device '" << data_dev << "'";
throw runtime_error(out.str());
}
try {
r = fstat(fd, &info);
if (r)
throw runtime_error("Couldn't stat data device");
if (!S_ISBLK(info.st_mode))
throw runtime_error("Data device is not a block device");
r = ioctl(fd, BLKGETSIZE64, &blksize);
if (r)
throw runtime_error("Couldn't get data device size");
if (blksize != (expected_size << 9))
throw runtime_error("Data device is not the expected size");
} catch (...) {
::close(fd);
throw;
}
return fd;
}
uint64_t block_to_byte(block_address b) {
return (b * block_size_) << 9;
}
int fd_;
unsigned block_size_;
};
class trim_visitor : public space_map_detail::visitor {
public:
trim_visitor(discard_emitter &e)
: emitter_(e) {
}
virtual void visit(space_map_detail::missing_counts const &mc) {
throw std::runtime_error("corrupt metadata, please use thin_check for details");
}
virtual void visit(block_address b, uint32_t count) {
if (last_visited_ && (b > *last_visited_ + 1))
emitter_.emit(*last_visited_ + 1, b);
last_visited_ = b;
}
private:
discard_emitter &emitter_;
boost::optional<block_address> last_visited_;
};
int trim(string const &metadata_dev, string const &data_dev) {
// We can trim any block that has zero count in the data
// space map.
metadata md(metadata_dev, 0);
if (!md.data_sm_->get_nr_free())
return 0;
discard_emitter de(data_dev, md.sb_.data_block_size_,
md.data_sm_->get_nr_blocks());
trim_visitor tv(de);
confirm_pool_is_not_active();
md.data_sm_->visit(tv);
return 0;
}
void usage(ostream &out, string const &cmd) {
out << "Usage: " << cmd << " [options] {device|file}\n"
<< "Options:\n"
<< " {--pool-inactive}\n"
<< " {-h|--help}\n"
<< " {-V|--version}" << endl;
}
struct flags {
boost::optional<string> metadata_dev;
boost::optional<string> data_dev;
};
}
//----------------------------------------------------------------
int thin_trim_main(int argc, char **argv)
{
int c;
flags fs;
const char shortopts[] = "hV";
const struct option longopts[] = {
{ "help", no_argument, NULL, 'h' },
{ "version", no_argument, NULL, 'V' },
{ "metadata-dev", required_argument, NULL, 0 },
{ "data-dev", required_argument, NULL, 1 },
{ "pool-inactive", no_argument, NULL, 2 },
{ NULL, no_argument, NULL, 0 }
};
while ((c = getopt_long(argc, argv, shortopts, longopts, NULL)) != -1) {
switch(c) {
case 0:
fs.metadata_dev = optarg;
break;
case 1:
fs.data_dev = optarg;
break;
case 'h':
usage(cout, basename(argv[0]));
return 0;
case 'V':
cout << THIN_PROVISIONING_TOOLS_VERSION << endl;
return 0;
default:
usage(cerr, basename(argv[0]));
return 1;
}
}
if (!fs.metadata_dev || !fs.data_dev) {
usage(cerr, basename(argv[0]));
return 1;
}
return trim(*fs.metadata_dev, *fs.data_dev);
}
//----------------------------------------------------------------