thin-provisioning-tools/persistent-data/block.tcc

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// Copyright (C) 2011 Red Hat, Inc. All rights reserved.
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//
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// 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 "block.h"
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
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#include <boost/bind.hpp>
#include <stdexcept>
#include <sstream>
//----------------------------------------------------------------
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// FIXME: give this namesace a name
namespace {
using namespace std;
int const DEFAULT_MODE = 0666;
unsigned const SECTOR_SHIFT = 9;
// FIXME: these will slow it down until we start doing async io.
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int const OPEN_FLAGS = O_DIRECT;
// FIXME: introduce a new exception for this, or at least lift this
// to exception.h
void syscall_failed(char const *call) {
char buffer[128];
char *msg = strerror_r(errno, buffer, sizeof(buffer));
ostringstream out;
out << "syscall '" << call << "' failed: " << msg;
throw runtime_error(out.str());
}
int open_file(string const &path, int flags) {
int fd = ::open(path.c_str(), OPEN_FLAGS | flags, DEFAULT_MODE);
if (fd < 0)
syscall_failed("open");
return fd;
}
bool file_exists(string const &path) {
struct ::stat info;
int r = ::stat(path.c_str(), &info);
if (r) {
if (errno == ENOENT)
return false;
syscall_failed("stat");
return false; // never get here
} else
return S_ISREG(info.st_mode) || S_ISBLK(info.st_mode);
}
int create_block_file(string const &path, off_t file_size) {
if (file_exists(path)) {
ostringstream out;
out << __FUNCTION__ << ": file '" << path << "' already exists";
throw runtime_error(out.str());
}
int fd = open_file(path, O_CREAT | O_RDWR);
// fallocate didn't seem to work
int r = ::lseek(fd, file_size, SEEK_SET);
if (r < 0)
syscall_failed("lseek");
return fd;
}
int open_block_file(string const &path, off_t min_size, bool writeable) {
if (!file_exists(path)) {
ostringstream out;
out << __FUNCTION__ << ": file '" << path << "' doesn't exist";
throw runtime_error(out.str());
}
return open_file(path, writeable ? O_RDWR : O_RDONLY);
}
};
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namespace persistent_data {
template <uint32_t BlockSize>
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block_manager<BlockSize>::block::block(block_cache &bc,
block_address location,
block_type bt,
typename validator::ptr v,
bool zero)
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: bc_(bc),
validator_(v),
bt_(bt),
dirty_(false),
unlocked_(false),
buffer_(0, true) // FIXME: we don't know if it's writeable here :(
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{
if (zero) {
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internal_ = &bc.get(location, block_cache::GF_ZERO | block_cache::GF_CAN_BLOCK);
dirty_ = true;
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buffer_.set_data(internal_->get_data());
} else {
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internal_ = &bc.get(location, block_cache::GF_CAN_BLOCK);
buffer_.set_data(internal_->get_data());
validator_->check(buffer_, internal_->get_index());
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}
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}
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template <uint32_t BlockSize>
block_manager<BlockSize>::block::~block()
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{
if (!unlocked_)
unlock();
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}
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template <uint32_t BlockSize>
void
block_manager<BlockSize>::block::unlock()
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{
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if (dirty_)
validator_->prepare(buffer_, internal_->get_index());
bc_.put(*internal_, dirty_ ? block_cache::PF_DIRTY : 0);
unlocked_ = true;
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}
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template <uint32_t BlockSize>
typename block_manager<BlockSize>::block_type
block_manager<BlockSize>::block::get_type() const
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{
return bt_;
}
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template <uint32_t BlockSize>
uint64_t
block_manager<BlockSize>::block::get_location() const
{
check_not_unlocked();
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return internal_->get_index();
}
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template <uint32_t BlockSize>
buffer<BlockSize> const &
block_manager<BlockSize>::block::get_buffer() const
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{
return buffer_;
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}
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template <uint32_t BlockSize>
buffer<BlockSize> &
block_manager<BlockSize>::block::get_buffer()
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{
return buffer_;
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}
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template <uint32_t BlockSize>
void
block_manager<BlockSize>::block::mark_dirty()
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{
check_not_unlocked();
dirty_ = true;
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}
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template <uint32_t BlockSize>
void
block_manager<BlockSize>::block::change_validator(typename block_manager<BlockSize>::validator::ptr v,
bool check)
{
check_not_unlocked();
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if (v.get() != validator_.get()) {
if (dirty_)
// It may have already happened, by calling
// this we ensure we're consistent.
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validator_->prepare(*internal_->get_data(), internal_->get_index());
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validator_ = v;
if (check)
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validator_->check(*internal_->get_data(), internal_->get_index());
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}
}
template <uint32_t BlockSize>
void
block_manager<BlockSize>::block::check_not_unlocked() const
{
if (unlocked_)
throw std::runtime_error("block prematurely unlocked");
}
//----------------------------------------------------------------
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template <uint32_t BlockSize>
block_manager<BlockSize>::read_ref::read_ref(block_manager<BlockSize> const &bm,
typename block::ptr b)
: bm_(&bm),
block_(b),
holders_(new unsigned)
{
*holders_ = 1;
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}
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template <uint32_t BlockSize>
block_manager<BlockSize>::read_ref::read_ref(read_ref const &rhs)
: bm_(rhs.bm_),
block_(rhs.block_),
holders_(rhs.holders_)
{
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(*holders_)++;
}
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template <uint32_t BlockSize>
block_manager<BlockSize>::read_ref::~read_ref()
{
if (!--(*holders_)) {
if (block_->get_type() == BT_SUPERBLOCK) {
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bm_->flush();
block_->unlock();
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bm_->flush();
} else
block_->unlock();
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delete holders_;
}
}
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template <uint32_t BlockSize>
typename block_manager<BlockSize>::read_ref const &
block_manager<BlockSize>::read_ref::operator =(read_ref const &rhs)
{
if (this != &rhs) {
block_ = rhs.block_;
bm_ = rhs.bm_;
holders_ = rhs.holders_;
(*holders_)++;
}
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return *this;
}
template <uint32_t BlockSize>
block_address
block_manager<BlockSize>::read_ref::get_location() const
{
return block_->get_location();
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}
template <uint32_t BlockSize>
buffer<BlockSize> const &
block_manager<BlockSize>::read_ref::data() const
{
return block_->get_buffer();
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}
//--------------------------------
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template <uint32_t BlockSize>
block_manager<BlockSize>::write_ref::write_ref(block_manager<BlockSize> const &bm,
typename block::ptr b)
: read_ref(bm, b)
{
b->mark_dirty();
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}
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template <uint32_t BlockSize>
buffer<BlockSize> &
block_manager<BlockSize>::write_ref::data()
{
return read_ref::block_->get_buffer();
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}
//----------------------------------------------------------------
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template <uint32_t BlockSize>
block_manager<BlockSize>::block_manager(std::string const &path,
block_address nr_blocks,
unsigned max_concurrent_blocks,
mode m)
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: fd_(open_block_file(path, nr_blocks * BlockSize, m == READ_WRITE)),
bc_(fd_, BlockSize >> SECTOR_SHIFT, nr_blocks, 1024u * 1024u * 4)
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{
}
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template <uint32_t BlockSize>
typename block_manager<BlockSize>::read_ref
block_manager<BlockSize>::read_lock(block_address location,
typename block_manager<BlockSize>::validator::ptr v) const
{
typename block::ptr b(new block(bc_, location, BT_NORMAL, v, false));
return read_ref(*this, b);
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}
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template <uint32_t BlockSize>
typename block_manager<BlockSize>::write_ref
block_manager<BlockSize>::write_lock(block_address location,
typename block_manager<BlockSize>::validator::ptr v)
{
typename block::ptr b(new block(bc_, location, BT_NORMAL, v, false));
return write_ref(*this, b);
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}
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template <uint32_t BlockSize>
typename block_manager<BlockSize>::write_ref
block_manager<BlockSize>::write_lock_zero(block_address location,
typename block_manager<BlockSize>::validator::ptr v)
{
typename block::ptr b(new block(bc_, location, BT_NORMAL, v, true));
return write_ref(*this, b);
}
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template <uint32_t BlockSize>
typename block_manager<BlockSize>::write_ref
block_manager<BlockSize>::superblock(block_address location,
typename block_manager<BlockSize>::validator::ptr v)
{
typename block::ptr b(new block(bc_, location, BT_SUPERBLOCK, v, false));
return write_ref(*this, b);
}
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template <uint32_t BlockSize>
typename block_manager<BlockSize>::write_ref
block_manager<BlockSize>::superblock_zero(block_address location,
typename block_manager<BlockSize>::validator::ptr v)
{
typename block::ptr b(new block(bc_, location, BT_SUPERBLOCK, v, true));
return write_ref(*this, b);
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}
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template <uint32_t BlockSize>
block_address
block_manager<BlockSize>::get_nr_blocks() const
{
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return bc_.get_nr_blocks();
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}
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template <uint32_t BlockSize>
void
block_manager<BlockSize>::write_block(typename block::ptr b) const
{
b->flush();
}
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template <uint32_t BlockSize>
void
block_manager<BlockSize>::flush() const
{
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bc_.flush();
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}
}
//----------------------------------------------------------------