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 "base/error_string.h"
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.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;
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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) {
ostringstream out;
out << "syscall '" << call << "' failed: " << base::error_string(errno);
throw runtime_error(out.str());
}
void syscall_failed(string const &call, string const &message)
{
ostringstream out;
out << "syscall '" << call << "' failed: " << base::error_string(errno) << "\n"
<< message;
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",
"Note: you cannot run this tool with these options on live metadata.");
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_EXCL | O_RDWR);
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int r = ::ftruncate(fd, file_size);
if (r < 0)
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syscall_failed("ftruncate");
return fd;
}
int open_block_file(string const &path, off_t min_size, bool writeable, bool excl = true) {
if (!file_exists(path)) {
ostringstream out;
out << __FUNCTION__ << ": file '" << path << "' doesn't exist";
throw runtime_error(out.str());
}
int flags = writeable ? O_RDWR : O_RDONLY;
if (excl)
flags |= O_EXCL;
return open_file(path, flags);
}
};
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namespace persistent_data {
template <uint32_t BlockSize>
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block_manager<BlockSize>::read_ref::read_ref(block_cache::block &b)
: b_(b)
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{
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}
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template <uint32_t BlockSize>
block_manager<BlockSize>::read_ref::read_ref(read_ref const &rhs)
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: b_(rhs.b_)
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{
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b_.get();
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}
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template <uint32_t BlockSize>
block_manager<BlockSize>::read_ref::~read_ref()
{
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b_.put();
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}
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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) {
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b_ = rhs.b_;
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b_.get();
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}
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return *this;
}
template <uint32_t BlockSize>
block_address
block_manager<BlockSize>::read_ref::get_location() const
{
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return b_.get_index();
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}
template <uint32_t BlockSize>
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void const *
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block_manager<BlockSize>::read_ref::data() const
{
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return b_.get_data();
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}
//--------------------------------
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template <uint32_t BlockSize>
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block_manager<BlockSize>::write_ref::write_ref(block_cache::block &b)
: read_ref(b),
ref_count_(NULL)
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{
}
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template <uint32_t BlockSize>
block_manager<BlockSize>::write_ref::write_ref(block_cache::block &b, unsigned &ref_count)
: read_ref(b),
ref_count_(&ref_count) {
if (*ref_count_)
throw std::runtime_error("superblock already locked");
(*ref_count_)++;
}
template <uint32_t BlockSize>
block_manager<BlockSize>::write_ref::write_ref(write_ref const &rhs)
: read_ref(rhs),
ref_count_(rhs.ref_count_) {
if (ref_count_)
(*ref_count_)++;
}
template <uint32_t BlockSize>
block_manager<BlockSize>::write_ref::~write_ref()
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{
if (ref_count_) {
if (!*ref_count_)
throw std::runtime_error("write_ref ref_count going below zero");
(*ref_count_)--;
}
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}
template <uint32_t BlockSize>
typename block_manager<BlockSize>::write_ref const &
block_manager<BlockSize>::write_ref::operator =(write_ref const &rhs)
{
if (&rhs != this) {
read_ref::operator =(rhs);
ref_count_ = rhs.ref_count_;
if (ref_count_)
(*ref_count_)++;
}
}
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template <uint32_t BlockSize>
void *
block_manager<BlockSize>::write_ref::data()
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{
return read_ref::b_.get_data();
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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,
bool excl)
: fd_(open_or_create_block_file(path, nr_blocks * BlockSize, m, excl)),
bc_(fd_, BlockSize >> SECTOR_SHIFT, nr_blocks, 1024u * 1024u * 16),
superblock_ref_count_(0)
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{
}
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template <uint32_t BlockSize>
int
block_manager<BlockSize>::open_or_create_block_file(string const &path, off_t file_size, mode m, bool excl)
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{
switch (m) {
case READ_ONLY:
return open_block_file(path, file_size, false, excl);
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case READ_WRITE:
return open_block_file(path, file_size, true, excl);
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case CREATE:
return create_block_file(path, file_size);
default:
throw std::runtime_error("unsupported mode");
}
}
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template <uint32_t BlockSize>
typename block_manager<BlockSize>::read_ref
block_manager<BlockSize>::read_lock(block_address location,
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typename bcache::validator::ptr v) const
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{
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block_cache::block &b = bc_.get(location, 0, v);
return read_ref(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,
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typename bcache::validator::ptr v)
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{
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block_cache::block &b = bc_.get(location, block_cache::GF_DIRTY, v);
return write_ref(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,
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typename bcache::validator::ptr v)
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{
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block_cache::block &b = bc_.get(location, block_cache::GF_ZERO, v);
return write_ref(b);
}
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template <uint32_t BlockSize>
typename block_manager<BlockSize>::write_ref
block_manager<BlockSize>::superblock(block_address location,
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typename bcache::validator::ptr v)
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{
if (bc_.get_nr_locked() > 0)
throw std::runtime_error("attempt to lock superblock while other locks are still held");
block_cache::block &b = bc_.get(location, block_cache::GF_DIRTY | block_cache::GF_BARRIER, v);
return write_ref(b, superblock_ref_count_);
}
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template <uint32_t BlockSize>
typename block_manager<BlockSize>::write_ref
block_manager<BlockSize>::superblock_zero(block_address location,
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typename bcache::validator::ptr v)
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{
if (bc_.get_nr_locked() > 0)
throw std::runtime_error("attempt to lock superblock while other locks are still held");
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block_cache::block &b = bc_.get(location, block_cache::GF_ZERO | block_cache::GF_BARRIER, v);
return write_ref(b, superblock_ref_count_);
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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>::prefetch(block_address b) const
{
bc_.prefetch(b);
}
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template <uint32_t BlockSize>
void
block_manager<BlockSize>::flush() const
{
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bc_.flush();
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}
}
//----------------------------------------------------------------