thin-provisioning-tools/caching/superblock.cc

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#include "base/bits.h"
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#include "caching/superblock.h"
using namespace base;
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using namespace caching;
using namespace superblock_damage;
//----------------------------------------------------------------
namespace {
using namespace base;
struct superblock_disk {
le32 csum;
le32 flags;
le64 blocknr;
__u8 uuid[16];
le64 magic;
le32 version;
__u8 policy_name[CACHE_POLICY_NAME_SIZE];
le32 policy_hint_size;
__u8 metadata_space_map_root[SPACE_MAP_ROOT_SIZE];
le64 mapping_root;
le64 hint_root;
le64 discard_root;
le64 discard_block_size;
le64 discard_nr_blocks;
le32 data_block_size; /* in 512-byte sectors */
le32 metadata_block_size; /* in 512-byte sectors */
le32 cache_blocks;
le32 compat_flags;
le32 compat_ro_flags;
le32 incompat_flags;
le32 read_hits;
le32 read_misses;
le32 write_hits;
le32 write_misses;
le32 policy_version[CACHE_POLICY_VERSION_SIZE];
} __attribute__ ((packed));
struct superblock_traits {
typedef superblock_disk disk_type;
typedef superblock value_type;
static void unpack(superblock_disk const &disk, superblock &value);
static void pack(superblock const &value, superblock_disk &disk);
};
uint32_t const SUPERBLOCK_MAGIC = 06142003;
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(superblock_flags::flag f)
{
flags_.insert(f);
}
void
superblock_flags::clear_flag(superblock_flags::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(SUPERBLOCK_LOCATION),
magic(SUPERBLOCK_MAGIC),
version(VERSION_END - 1u),
policy_hint_size(4),
mapping_root(0),
hint_root(0),
discard_root(0),
discard_block_size(0),
discard_nr_blocks(0),
data_block_size(0),
metadata_block_size(8),
cache_blocks(0),
compat_flags(0),
compat_ro_flags(0),
incompat_flags(0),
read_hits(0),
read_misses(0),
write_hits(0),
write_misses(0)
{
::memset(uuid, 0, sizeof(uuid));
::memset(policy_name, 0, sizeof(policy_name));
::memset(policy_version, 0, sizeof(policy_version));
::memset(metadata_space_map_root, 0, sizeof(metadata_space_map_root));
}
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//----------------------------------------------------------------
void
superblock_traits::unpack(superblock_disk const &disk, superblock &core)
{
core.compat_flags = to_cpu<uint32_t>(disk.compat_flags);
core.compat_ro_flags = to_cpu<uint32_t>(disk.compat_ro_flags);
core.incompat_flags = to_cpu<uint32_t>(disk.incompat_flags);
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core.csum = to_cpu<uint32_t>(disk.csum);
core.flags = superblock_flags(to_cpu<uint32_t>(disk.flags));
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core.blocknr = to_cpu<uint64_t>(disk.blocknr);
::memcpy(core.uuid, disk.uuid, sizeof(core.uuid));
core.magic = to_cpu<uint64_t>(disk.magic);
core.version = to_cpu<uint32_t>(disk.version);
::memcpy(core.policy_name, disk.policy_name, sizeof(core.policy_name));
for (unsigned i = 0; i < CACHE_POLICY_VERSION_SIZE; i++)
core.policy_version[i] = to_cpu<uint32_t>(disk.policy_version[i]);
core.policy_hint_size = test_bit(core.incompat_flags, VARIABLE_HINT_SIZE_BIT) ?
to_cpu<uint32_t>(disk.policy_hint_size) : 4;
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::memcpy(core.metadata_space_map_root,
disk.metadata_space_map_root,
sizeof(core.metadata_space_map_root));
core.mapping_root = to_cpu<uint64_t>(disk.mapping_root);
core.hint_root = to_cpu<uint64_t>(disk.hint_root);
core.discard_root = to_cpu<uint64_t>(disk.discard_root);
core.discard_block_size = to_cpu<uint64_t>(disk.discard_block_size);
core.discard_nr_blocks = to_cpu<uint64_t>(disk.discard_nr_blocks);
core.data_block_size = to_cpu<uint32_t>(disk.data_block_size);
core.metadata_block_size = to_cpu<uint32_t>(disk.metadata_block_size);
core.cache_blocks = to_cpu<uint32_t>(disk.cache_blocks);
core.read_hits = to_cpu<uint32_t>(disk.read_hits);
core.read_misses = to_cpu<uint32_t>(disk.read_misses);
core.write_hits = to_cpu<uint32_t>(disk.write_hits);
core.write_misses = to_cpu<uint32_t>(disk.write_misses);
}
void
superblock_traits::pack(superblock const &sb, superblock_disk &disk)
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{
// We adjust some of the flags in the superblock, so make a copy
superblock core(sb);
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disk.csum = to_disk<le32>(core.csum);
disk.flags = to_disk<le32>(core.flags.encode());
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disk.blocknr = to_disk<le64>(core.blocknr);
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::memcpy(disk.uuid, core.uuid, sizeof(disk.uuid));
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disk.magic = to_disk<le64>(core.magic);
disk.version = to_disk<le32>(core.version);
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::memcpy(disk.policy_name, core.policy_name, sizeof(disk.policy_name));
for (unsigned i = 0; i < CACHE_POLICY_VERSION_SIZE; i++)
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disk.policy_version[i] = to_disk<le32>(core.policy_version[i]);
if (core.policy_hint_size != 4) {
set_bit(core.incompat_flags, VARIABLE_HINT_SIZE_BIT);
disk.policy_hint_size = to_disk<le32>(core.policy_hint_size);
} else {
clear_bit(core.incompat_flags, VARIABLE_HINT_SIZE_BIT);
disk.policy_hint_size = to_disk<le32>(0u);
}
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::memcpy(disk.metadata_space_map_root,
core.metadata_space_map_root,
sizeof(disk.metadata_space_map_root));
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disk.mapping_root = to_disk<le64>(core.mapping_root);
disk.hint_root = to_disk<le64>(core.hint_root);
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disk.discard_root = to_disk<le64>(core.discard_root);
disk.discard_block_size = to_disk<le64>(core.discard_block_size);
disk.discard_nr_blocks = to_disk<le64>(core.discard_nr_blocks);
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disk.data_block_size = to_disk<le32>(core.data_block_size);
disk.metadata_block_size = to_disk<le32>(core.metadata_block_size);
disk.cache_blocks = to_disk<le32>(core.cache_blocks);
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disk.compat_flags = to_disk<le32>(core.compat_flags);
disk.compat_ro_flags = to_disk<le32>(core.compat_ro_flags);
disk.incompat_flags = to_disk<le32>(core.incompat_flags);
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disk.read_hits = to_disk<le32>(core.read_hits);
disk.read_misses = to_disk<le32>(core.read_misses);
disk.write_hits = to_disk<le32>(core.write_hits);
disk.write_misses = to_disk<le32>(core.write_misses);
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}
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//--------------------------------
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)
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{
}
void
superblock_invalid::visit(damage_visitor &v) const
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{
v.visit(*this);
}
//--------------------------------
// anonymous namespace doesn't work for some reason
namespace validator {
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using namespace persistent_data;
uint32_t const VERSION = 1;
unsigned const SECTOR_TO_BLOCK_SHIFT = 3;
uint32_t const SUPERBLOCK_CSUM_SEED = 9031977;
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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);
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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");
}
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virtual void prepare(void *raw, block_address location) const {
superblock_disk *sbd = reinterpret_cast<superblock_disk *>(raw);
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crc32c sum(SUPERBLOCK_CSUM_SEED);
sum.append(&sbd->flags, MD_BLOCK_SIZE - sizeof(uint32_t));
sbd->csum = to_disk<base::le32>(sum.get_sum());
}
};
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bcache::validator::ptr mk_v() {
return bcache::validator::ptr(new sb_validator);
}
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}
//--------------------------------
superblock
caching::read_superblock(block_manager<>::ptr bm, block_address location)
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{
using namespace validator;
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superblock sb;
block_manager<>::read_ref r = bm->read_lock(location, mk_v());
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superblock_disk const *sbd = reinterpret_cast<superblock_disk const *>(r.data());
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superblock_traits::unpack(*sbd, sb);
return sb;
}
void
caching::write_superblock(block_manager<>::ptr bm, superblock const &sb, block_address location)
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{
using namespace validator;
block_manager<>::write_ref w = bm->superblock_zero(location, mk_v());
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superblock_traits::pack(sb, *reinterpret_cast<superblock_disk *>(w.data()));
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}
void
caching::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 (::strnlen((char const *) sb.policy_name, CACHE_POLICY_NAME_SIZE) == CACHE_POLICY_NAME_SIZE) {
visitor.visit(superblock_invalid("policy name is not null terminated"));
}
if (sb.policy_hint_size % 4 || sb.policy_hint_size > 128) {
ostringstream msg;
msg << "policy hint size invalid: " << sb.policy_hint_size;
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.compat_flags != 0) {
ostringstream msg;
msg << "compat_flags invalid (can only be 0): " << sb.compat_flags;
visitor.visit(superblock_invalid(msg.str()));
}
if (sb.compat_ro_flags != 0) {
ostringstream msg;
msg << "compat_ro_flags invalid (can only be 0): " << sb.compat_ro_flags;
visitor.visit(superblock_invalid(msg.str()));
}
if (sb.incompat_flags & ~(1 << VARIABLE_HINT_SIZE_BIT)) {
ostringstream msg;
msg << "incompat_flags invalid (can only be 0): " << sb.incompat_flags;
visitor.visit(superblock_invalid(msg.str()));
}
}
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void
caching::check_superblock(persistent_data::block_manager<>::ptr bm,
block_address nr_metadata_blocks,
damage_visitor &visitor)
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{
superblock sb;
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try {
sb = read_superblock(bm, SUPERBLOCK_LOCATION);
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} 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()));
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}
check_superblock(sb, nr_metadata_blocks, visitor);
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}
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//----------------------------------------------------------------