thin-provisioning-tools/thin-provisioning/thin_trim.cc
Joe Thornber e801cc607b [block_manager] Hard code block size to 4k.
We're never going to use anything other than 4k, and by hard coding it we
avoid making block_manager a template.
2020-04-30 14:30:01 +01:00

224 lines
4.7 KiB
C++

#include <iostream>
#include <getopt.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <linux/fs.h>
#include <libgen.h>
#include <fcntl.h>
#undef BLOCK_SIZE
#ifndef BLKDISCARD
#define BLKDISCARD _IO(0x12,119)
#endif
#include "persistent-data/file_utils.h"
#include "thin-provisioning/commands.h"
#include "metadata.h"
#include "version.h"
using namespace persistent_data;
using namespace std;
using namespace thin_provisioning;
//----------------------------------------------------------------
namespace {
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];
cerr << "emitting discard for blocks (" << b << ", " << e << "]\n";
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_iterator : public space_map::iterator {
public:
trim_iterator(discard_emitter &e)
: emitter_(e) {
}
virtual void operator() (block_address b, ref_t count) {
highest_ = b;
if (count) {
if (last_referenced_ && (b > *last_referenced_ + 1))
emitter_.emit(*last_referenced_ + 1, b);
last_referenced_ = b;
}
}
void complete() {
if (last_referenced_) {
if (*last_referenced_ != *highest_)
emitter_.emit(*last_referenced_, *highest_ + 1ull);
} else if (highest_)
emitter_.emit(0ull, *highest_ + 1);
}
private:
discard_emitter &emitter_;
boost::optional<block_address> last_referenced_;
boost::optional<block_address> highest_;
};
int trim(string const &metadata_dev, string const &data_dev) {
cerr << "in trim\n";
// We can trim any block that has zero count in the data
// space map.
block_manager::ptr bm = open_bm(metadata_dev, block_manager::READ_ONLY);
metadata md(bm);
if (!md.data_sm_->get_nr_free()) {
cerr << "All data blocks allocated, nothing to discard\n";
return 0;
}
discard_emitter de(data_dev, md.sb_.data_block_size_,
md.data_sm_->get_nr_blocks());
trim_iterator ti(de);
md.data_sm_->iterate(ti);
ti.complete();
return 0;
}
struct flags {
boost::optional<string> metadata_dev;
boost::optional<string> data_dev;
};
}
//----------------------------------------------------------------
thin_trim_cmd::thin_trim_cmd()
: command("thin_trim")
{
}
void
thin_trim_cmd::usage(std::ostream &out) const
{
out << "Usage: " << get_name() << " [options] --metadata-dev {device|file} --data-dev {device|file}\n"
<< "Options:\n"
<< " {-h|--help}\n"
<< " {-V|--version}" << endl;
}
int
thin_trim_cmd::run(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 2:
cerr << "--pool-inactive no longer required since we ensure the metadata device is opened exclusively.\n";
break;
case 'h':
usage(cout);
return 0;
case 'V':
cout << THIN_PROVISIONING_TOOLS_VERSION << endl;
return 0;
default:
usage(cerr);
return 1;
}
}
if (!fs.metadata_dev || !fs.data_dev) {
usage(cerr);
return 1;
}
return trim(*fs.metadata_dev, *fs.data_dev);
}
//----------------------------------------------------------------