thin-provisioning-tools/era/superblock.cc
2014-07-25 14:46:51 +01:00

338 lines
8.6 KiB
C++

#include "era/superblock.h"
#include "persistent-data/checksum.h"
#include "persistent-data/errors.h"
using namespace base;
using namespace era;
using namespace superblock_damage;
using namespace persistent_data;
//----------------------------------------------------------------
namespace {
using namespace base;
size_t const SPACE_MAP_ROOT_SIZE = 128;
size_t const UUID_LEN = 16;
struct superblock_disk {
le32 csum;
le32 flags;
le64 blocknr;
__u8 uuid[UUID_LEN];
le64 magic;
le32 version;
__u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
le32 data_block_size;
le32 metadata_block_size;
le32 nr_blocks;
le32 current_era;
era_detail_disk current_detail;
le64 writeset_tree_root;
le64 era_array_root;
le64 metadata_snap;
} __attribute__ ((packed));
struct superblock_traits {
typedef superblock_disk disk_type;
typedef superblock value_type;
static void unpack(disk_type const &disk, value_type &value);
static void pack(value_type const &value, disk_type &disk);
};
uint32_t const SUPERBLOCK_MAGIC = 2126579579;
uint32_t const VERSION_BEGIN = 1;
uint32_t const VERSION_END = 2;
}
//----------------------------------------------------------------
superblock_flags::superblock_flags()
: unhandled_flags_(0)
{
}
superblock_flags::superblock_flags(uint32_t bits)
{
if (bits & (1 << CLEAN_SHUTDOWN_BIT)) {
flags_.insert(CLEAN_SHUTDOWN);
bits &= ~(1 << CLEAN_SHUTDOWN_BIT);
}
unhandled_flags_ = bits;
}
void
superblock_flags::set_flag(flag f)
{
flags_.insert(f);
}
void
superblock_flags::clear_flag(flag f)
{
flags_.erase(f);
}
bool
superblock_flags::get_flag(flag f) const
{
return flags_.find(f) != flags_.end();
}
uint32_t
superblock_flags::encode() const
{
uint32_t r = 0;
if (get_flag(CLEAN_SHUTDOWN))
r = r | (1 << CLEAN_SHUTDOWN_BIT);
return r;
}
uint32_t
superblock_flags::get_unhandled_flags() const
{
return unhandled_flags_;
}
//----------------------------------------------------------------
superblock::superblock()
: csum(0),
blocknr(0),
flags(),
magic(SUPERBLOCK_MAGIC),
version(VERSION_END - 1),
data_block_size(0),
metadata_block_size(8),
nr_blocks(0),
current_era(0),
writeset_tree_root(0),
era_array_root(0)
{
memset(uuid, 0, sizeof(uuid));
memset(metadata_space_map_root, 0, sizeof(metadata_space_map_root));
}
//----------------------------------------------------------------
void
superblock_traits::unpack(disk_type const &disk, value_type &value)
{
//value.flags = to_cpu<uint32_t>(disk.flags);
value.blocknr = to_cpu<uint64_t>(disk.blocknr);
value.magic = to_cpu<uint64_t>(disk.magic);
value.version = to_cpu<uint32_t>(disk.version);
memcpy(value.metadata_space_map_root, disk.metadata_space_map_root,
sizeof(value.metadata_space_map_root));
value.data_block_size = to_cpu<uint32_t>(disk.data_block_size);
value.metadata_block_size = to_cpu<uint32_t>(disk.metadata_block_size);
value.nr_blocks = to_cpu<uint32_t>(disk.nr_blocks);
value.current_era = to_cpu<uint32_t>(disk.current_era);
era_detail_traits::unpack(disk.current_detail, value.current_detail);
value.writeset_tree_root = to_cpu<uint64_t>(disk.writeset_tree_root);
value.era_array_root = to_cpu<uint64_t>(disk.era_array_root);
block_address ms = to_cpu<uint64_t>(disk.metadata_snap);
value.metadata_snap = (ms == SUPERBLOCK_LOCATION) ?
boost::optional<block_address>() :
boost::optional<block_address>(ms);
}
void
superblock_traits::pack(value_type const &value, disk_type &disk)
{
//disk.flags = to_disk<uint32_t>(value.flags);
disk.blocknr = to_disk<le64>(value.blocknr);
disk.magic = to_disk<le64>(value.magic);
disk.version = to_disk<le32>(value.version);
memcpy(disk.metadata_space_map_root, value.metadata_space_map_root,
sizeof(disk.metadata_space_map_root));
disk.data_block_size = to_disk<le32>(value.data_block_size);
disk.metadata_block_size = to_disk<le32>(value.metadata_block_size);
disk.nr_blocks = to_disk<le32>(value.nr_blocks);
disk.current_era = to_disk<le32>(value.current_era);
era_detail_traits::pack(value.current_detail, disk.current_detail);
disk.writeset_tree_root = to_disk<le64>(value.writeset_tree_root);
disk.era_array_root = to_disk<le64>(value.era_array_root);
disk.metadata_snap = value.metadata_snap ?
to_disk<le64>(*value.metadata_snap) :
to_disk<le64>(SUPERBLOCK_LOCATION);
}
//--------------------------------
superblock_corrupt::superblock_corrupt(std::string const &desc)
: damage(desc)
{
}
void
superblock_corrupt::visit(damage_visitor &v) const
{
v.visit(*this);
}
superblock_invalid::superblock_invalid(std::string const &desc)
: damage(desc)
{
}
void
superblock_invalid::visit(damage_visitor &v) const
{
v.visit(*this);
}
//----------------------------------------------------------------
namespace era_validator {
using namespace persistent_data;
uint32_t const VERSION = 1;
unsigned const SECTOR_TO_BLOCK_SHIFT = 3;
uint32_t const SUPERBLOCK_CSUM_SEED = 146538381;
// FIXME: turn into a template, we have 3 similar classes now
struct sb_validator : public bcache::validator {
virtual void check(void const *raw, block_address location) const {
superblock_disk const *sbd = reinterpret_cast<superblock_disk const *>(raw);
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(void *raw, block_address location) const {
superblock_disk *sbd = reinterpret_cast<superblock_disk *>(raw);
crc32c sum(SUPERBLOCK_CSUM_SEED);
sum.append(&sbd->flags, MD_BLOCK_SIZE - sizeof(uint32_t));
sbd->csum = to_disk<base::le32>(sum.get_sum());
}
};
bcache::validator::ptr mk_v() {
return bcache::validator::ptr(new sb_validator);
}
}
//----------------------------------------------------------------
superblock
era::read_superblock(block_manager<>::ptr bm, block_address location)
{
superblock sb;
block_manager<>::read_ref r = bm->read_lock(location, era_validator::mk_v());
superblock_disk const *sbd = reinterpret_cast<superblock_disk const *>(r.data());
superblock_traits::unpack(*sbd, sb);
return sb;
}
void
era::write_superblock(block_manager<>::ptr bm, superblock const &sb, block_address location)
{
block_manager<>::write_ref w = bm->superblock_zero(location, era_validator::mk_v());
superblock_traits::pack(sb, *reinterpret_cast<superblock_disk *>(w.data()));
}
void
era::check_superblock(superblock const &sb,
block_address nr_metadata_blocks,
damage_visitor &visitor)
{
if (sb.flags.get_unhandled_flags()) {
ostringstream msg;
msg << "invalid flags: " << sb.flags.get_unhandled_flags();
visitor.visit(superblock_invalid(msg.str()));
}
if (sb.blocknr >= nr_metadata_blocks) {
ostringstream msg;
msg << "blocknr out of bounds: " << sb.blocknr << " >= " << nr_metadata_blocks;
visitor.visit(superblock_invalid(msg.str()));
}
if (sb.magic != SUPERBLOCK_MAGIC) {
ostringstream msg;
msg << "magic in incorrect: " << sb.magic;
visitor.visit(superblock_invalid(msg.str()));
}
if (sb.version >= VERSION_END) {
ostringstream msg;
msg << "version incorrect: " << sb.version;
visitor.visit(superblock_invalid(msg.str()));
}
if (sb.version < VERSION_BEGIN) {
ostringstream msg;
msg << "version incorrect: " << sb.version;
visitor.visit(superblock_invalid(msg.str()));
}
if (sb.metadata_block_size != 8) {
ostringstream msg;
msg << "metadata block size incorrect: " << sb.metadata_block_size;
visitor.visit(superblock_invalid(msg.str()));
}
if (sb.writeset_tree_root == SUPERBLOCK_LOCATION) {
string msg("writeset tree root points back to the superblock");
visitor.visit(superblock_invalid(msg));
}
if (sb.era_array_root == SUPERBLOCK_LOCATION) {
string msg("era array root points back to the superblock");
visitor.visit(superblock_invalid(msg));
}
if (sb.writeset_tree_root == sb.era_array_root) {
ostringstream msg;
msg << "writeset tree root and era array both point to the same block: "
<< sb.era_array_root;
visitor.visit(superblock_invalid(msg.str()));
}
}
void
era::check_superblock(persistent_data::block_manager<>::ptr bm,
block_address nr_metadata_blocks,
damage_visitor &visitor)
{
superblock sb;
try {
sb = read_superblock(bm, SUPERBLOCK_LOCATION);
} catch (std::exception const &e) {
// FIXME: what if it fails due to a zero length file? Not
// really a corruption, so much as an io error. Should we
// separate these?
visitor.visit(superblock_corrupt(e.what()));
}
check_superblock(sb, nr_metadata_blocks, visitor);
}
//----------------------------------------------------------------