thin-provisioning-tools/metadata.cc
2011-10-28 12:25:06 +01:00

116 lines
3.4 KiB
C++

#include "metadata.h"
#include "math_utils.h"
#include "space_map_disk.h"
#include "core_map.h"
#include <linux/fs.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
using namespace thin_provisioning;
//----------------------------------------------------------------
namespace {
uint32_t const SUPERBLOCK_MAGIC = 27022010;
uint32_t const VERSION = 1;
unsigned const METADATA_CACHE_SIZE = 1024;
unsigned const SECTOR_TO_BLOCK_SHIFT = 3;
block_address get_nr_blocks(string const &path) {
struct stat info;
block_address nr_blocks;
int r = ::stat(path.c_str(), &info);
if (r)
throw runtime_error("Couldn't stat dev path");
if (S_ISREG(info.st_mode))
nr_blocks = div_down<block_address>(info.st_size, MD_BLOCK_SIZE);
else if (S_ISBLK(info.st_mode)) {
// To get the size of a block device we need to
// open it, and then make an ioctl call.
int fd = ::open(path.c_str(), O_RDONLY);
if (fd < 0)
throw runtime_error("couldn't open block device to ascertain size");
r = ::ioctl(fd, BLKGETSIZE64, &nr_blocks);
if (r) {
::close(fd);
throw runtime_error("ioctl BLKGETSIZE64 failed");
}
::close(fd);
nr_blocks = div_down<block_address>(nr_blocks, MD_BLOCK_SIZE);
} else
throw runtime_error("bad path");
return nr_blocks;
}
transaction_manager::ptr
open_tm(string const &dev_path) {
block_address nr_blocks = get_nr_blocks(dev_path);
block_manager<>::ptr bm(new block_manager<>(dev_path, nr_blocks, 8));
space_map::ptr sm(new core_map(nr_blocks));
transaction_manager::ptr tm(new transaction_manager(bm, sm));
return tm;
}
superblock read_superblock(block_manager<>::ptr bm) {
superblock sb;
block_manager<>::read_ref r = bm->read_lock(SUPERBLOCK_LOCATION);
superblock_disk const *sbd = reinterpret_cast<superblock_disk const *>(&r.data());
crc32c sum(160774);
sum.append(&sbd->flags_, MD_BLOCK_SIZE - sizeof(uint32_t));
if (sum.get_sum() != to_cpu<uint32_t>(sbd->csum_)) {
ostringstream out;
out << "bad checksum in superblock, calculated "
<< sum.get_sum()
<< ", superblock contains " << to_cpu<uint32_t>(sbd->csum_);
throw runtime_error(out.str());
}
superblock_traits::unpack(*sbd, sb);
return sb;
}
}
//----------------------------------------------------------------
metadata::metadata(std::string const &dev_path)
: tm_(open_tm(dev_path)),
sb_(read_superblock(tm_->get_bm())),
metadata_sm_(open_metadata_sm(tm_, static_cast<void *>(&sb_.metadata_space_map_root_))),
data_sm_(open_disk_sm(tm_, static_cast<void *>(&sb_.data_space_map_root_))),
details_(tm_, sb_.device_details_root_, device_details_traits::ref_counter()),
mappings_top_level_(tm_, sb_.data_mapping_root_, mtree_ref_counter(tm_)),
mappings_(tm_, sb_.data_mapping_root_, block_time_ref_counter(data_sm_))
{
}
#if 0
::memset(&sb_, 0, sizeof(sb_));
sb_.data_mapping_root_ = mappings_.get_root();
sb_.device_details_root_ = details_.get_root();
sb_.metadata_block_size_ = MD_BLOCK_SIZE;
sb_.metadata_nr_blocks_ = tm_->get_bm()->get_nr_blocks();
#endif
void
metadata::commit()
{
sb_.data_mapping_root_ = mappings_.get_root();
sb_.device_details_root_ = details_.get_root();
write_ref superblock = tm_->get_bm()->superblock(SUPERBLOCK_LOCATION);
superblock_disk *disk = reinterpret_cast<superblock_disk *>(superblock.data());
superblock_traits::pack(sb_, *disk);
}
//----------------------------------------------------------------