thin-provisioning-tools/thin-provisioning/metadata.cc
2013-01-02 12:55:41 +00:00

220 lines
7.7 KiB
C++

// Copyright (C) 2011 Red Hat, Inc. All rights reserved.
//
// This file is part of the thin-provisioning-tools source.
//
// thin-provisioning-tools is free software: you can redistribute it
// and/or modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation, either version 3 of
// the License, or (at your option) any later version.
//
// thin-provisioning-tools is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty
// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with thin-provisioning-tools. If not, see
// <http://www.gnu.org/licenses/>.
#include "thin-provisioning/metadata.h"
#include "persistent-data/math_utils.h"
#include "persistent-data/space_map_core.h"
#include "persistent-data/space_map_disk.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;
uint32_t const SUPERBLOCK_CSUM_SEED = 160774;
struct superblock_validator : public block_manager<>::validator {
virtual void check(buffer<> const &b, block_address location) const {
superblock_disk const *sbd = reinterpret_cast<superblock_disk const *>(&b);
crc32c sum(SUPERBLOCK_CSUM_SEED);
sum.append(&sbd->flags_, MD_BLOCK_SIZE - sizeof(uint32_t));
if (sum.get_sum() != to_cpu<uint32_t>(sbd->csum_))
throw checksum_error("bad checksum in superblock");
}
virtual void prepare(buffer<> &b, block_address location) const {
superblock_disk *sbd = reinterpret_cast<superblock_disk *>(&b);
crc32c sum(SUPERBLOCK_CSUM_SEED);
sum.append(&sbd->flags_, MD_BLOCK_SIZE - sizeof(uint32_t));
sbd->csum_ = to_disk<base::__le32>(sum.get_sum());
}
};
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) && info.st_size)
nr_blocks = div_up<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, bool writeable) {
block_address nr_blocks = get_nr_blocks(dev_path);
block_manager<>::ptr bm(new block_manager<>(dev_path, nr_blocks, 1, writeable));
space_map::ptr sm(new core_map(nr_blocks));
sm->inc(SUPERBLOCK_LOCATION);
transaction_manager::ptr tm(new transaction_manager(bm, sm));
return tm;
}
superblock
read_superblock(block_manager<>::ptr bm, block_address location = SUPERBLOCK_LOCATION) {
superblock sb;
block_manager<>::read_ref r = bm->read_lock(location,
mk_validator(new superblock_validator));
superblock_disk const *sbd = reinterpret_cast<superblock_disk const *>(&r.data());
superblock_traits::unpack(*sbd, sb);
return sb;
}
void
copy_space_maps(space_map::ptr lhs, space_map::ptr rhs) {
for (block_address b = 0; b < rhs->get_nr_blocks(); b++) {
uint32_t count = rhs->get_count(b);
if (count > 0)
lhs->set_count(b, rhs->get_count(b));
}
}
}
//----------------------------------------------------------------
metadata::metadata(std::string const &dev_path, open_type ot,
sector_t data_block_size, block_address nr_data_blocks)
{
switch (ot) {
case OPEN:
tm_ = open_tm(dev_path, false);
sb_ = read_superblock(tm_->get_bm());
if (sb_.version_ != 1)
throw runtime_error("unknown metadata version");
metadata_sm_ = open_metadata_sm(tm_, &sb_.metadata_space_map_root_);
tm_->set_sm(metadata_sm_);
data_sm_ = open_disk_sm(tm_, static_cast<void *>(&sb_.data_space_map_root_));
details_ = detail_tree::ptr(new detail_tree(tm_, sb_.device_details_root_, device_details_traits::ref_counter()));
mappings_top_level_ = dev_tree::ptr(new dev_tree(tm_, sb_.data_mapping_root_, mtree_ref_counter(tm_)));
mappings_ = mapping_tree::ptr(new mapping_tree(tm_, sb_.data_mapping_root_, block_time_ref_counter(data_sm_)));
break;
case CREATE:
tm_ = open_tm(dev_path, true);
space_map::ptr core = tm_->get_sm();
metadata_sm_ = create_metadata_sm(tm_, tm_->get_bm()->get_nr_blocks());
copy_space_maps(metadata_sm_, core);
tm_->set_sm(metadata_sm_);
data_sm_ = create_disk_sm(tm_, nr_data_blocks);
details_ = detail_tree::ptr(new detail_tree(tm_, device_details_traits::ref_counter()));
mappings_ = mapping_tree::ptr(new mapping_tree(tm_, block_time_ref_counter(data_sm_)));
mappings_top_level_ = dev_tree::ptr(new dev_tree(tm_, mappings_->get_root(), mtree_ref_counter(tm_)));
::memset(&sb_, 0, sizeof(sb_));
sb_.magic_ = SUPERBLOCK_MAGIC;
sb_.version_ = 1;
sb_.data_mapping_root_ = mappings_->get_root();
sb_.device_details_root_ = details_->get_root();
sb_.data_block_size_ = data_block_size;
sb_.metadata_block_size_ = MD_BLOCK_SIZE;
sb_.metadata_nr_blocks_ = tm_->get_bm()->get_nr_blocks();
break;
}
}
metadata::metadata(std::string const &dev_path, block_address metadata_snap)
{
tm_ = open_tm(dev_path, false);
sb_ = read_superblock(tm_->get_bm(), metadata_snap);
// We don't open the metadata sm for a held root
//metadata_sm_ = open_metadata_sm(tm_, &sb_.metadata_space_map_root_);
tm_->set_sm(metadata_sm_);
data_sm_ = open_disk_sm(tm_, static_cast<void *>(&sb_.data_space_map_root_));
details_ = detail_tree::ptr(new detail_tree(tm_, sb_.device_details_root_, device_details_traits::ref_counter()));
mappings_top_level_ = dev_tree::ptr(new dev_tree(tm_, sb_.data_mapping_root_, mtree_ref_counter(tm_)));
mappings_ = mapping_tree::ptr(new mapping_tree(tm_, sb_.data_mapping_root_, block_time_ref_counter(data_sm_)));
}
namespace {
void print_superblock(superblock const &sb) {
using namespace std;
cerr << "superblock " << sb.csum_ << endl
<< "flags " << sb.flags_ << endl
<< "blocknr " << sb.blocknr_ << endl
<< "transaction id " << sb.trans_id_ << endl
<< "data mapping root " << sb.data_mapping_root_ << endl
<< "details root " << sb.device_details_root_ << endl
<< "data block size " << sb.data_block_size_ << endl
<< "metadata block size " << sb.metadata_block_size_ << endl
<< "metadata nr blocks " << sb.metadata_nr_blocks_ << endl
;
}
}
void
metadata::commit()
{
sb_.data_mapping_root_ = mappings_->get_root();
sb_.device_details_root_ = details_->get_root();
data_sm_->commit();
data_sm_->copy_root(&sb_.data_space_map_root_, sizeof(sb_.data_space_map_root_));
metadata_sm_->commit();
metadata_sm_->copy_root(&sb_.metadata_space_map_root_, sizeof(sb_.metadata_space_map_root_));
print_superblock(sb_);
superblock_validator v;
write_ref superblock = tm_->get_bm()->superblock_zero(SUPERBLOCK_LOCATION,
mk_validator(new superblock_validator()));
superblock_disk *disk = reinterpret_cast<superblock_disk *>(superblock.data().raw());
superblock_traits::pack(sb_, *disk);
}
//----------------------------------------------------------------