thin-provisioning-tools/transaction_manager.cc

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#include "transaction_manager.h"
#include <string.h>
using namespace boost;
using namespace persistent_data;
using namespace std;
//----------------------------------------------------------------
2011-09-01 15:12:57 +05:30
transaction_manager::transaction_manager(block_manager<>::ptr bm,
space_map::ptr sm)
: bm_(bm),
sm_(sm)
{
}
transaction_manager::~transaction_manager()
{
}
transaction_manager::write_ref
transaction_manager::begin(block_address superblock)
{
write_ref wr = bm_->superblock(superblock);
wipe_shadow_table();
return wr;
}
transaction_manager::write_ref
transaction_manager::begin(block_address superblock, validator v)
{
write_ref wr = bm_->superblock(superblock, v);
wipe_shadow_table();
return wr;
}
// FIXME: these explicit try/catches are gross
transaction_manager::write_ref
transaction_manager::new_block()
{
block_address b = sm_->new_block();
try {
add_shadow(b);
try {
return bm_->write_lock_zero(b);
} catch (...) {
remove_shadow(b);
throw;
}
} catch (...) {
sm_->dec(b);
throw;
}
}
transaction_manager::write_ref
transaction_manager::new_block(validator v)
{
block_address b = sm_->new_block();
try {
add_shadow(b);
try {
return bm_->write_lock_zero(b, v);
} catch (...) {
remove_shadow(b);
throw;
}
} catch (...) {
sm_->dec(b);
throw;
}
}
// FIXME: make exception safe
pair<transaction_manager::write_ref, bool>
transaction_manager::shadow(block_address orig)
{
if (is_shadow(orig) &&
!sm_->count_possibly_greater_than_one(orig))
return make_pair(bm_->write_lock(orig), false);
read_ref src = bm_->read_lock(orig);
write_ref dest = bm_->write_lock_zero(sm_->new_block());
::memcpy(dest.data(), src.data(), MD_BLOCK_SIZE);
ref_t count = sm_->get_count(orig);
if (count == 0)
throw runtime_error("shadowing free block");
sm_->dec(orig);
add_shadow(dest.get_location());
return make_pair(dest, count > 1);
}
// FIXME: duplicate code
pair<transaction_manager::write_ref, bool>
transaction_manager::shadow(block_address orig, validator v)
{
if (is_shadow(orig) &&
!sm_->count_possibly_greater_than_one(orig))
return make_pair(bm_->write_lock(orig, v), false);
read_ref src = bm_->read_lock(orig, v);
write_ref dest = bm_->write_lock_zero(sm_->new_block(), v);
::memcpy(dest.data(), src.data(), MD_BLOCK_SIZE);
ref_t count = sm_->get_count(orig);
if (count == 0)
throw runtime_error("shadowing free block");
sm_->dec(orig);
add_shadow(dest.get_location());
return make_pair(dest, count > 1);
}
transaction_manager::read_ref
transaction_manager::read_lock(block_address b)
{
return bm_->read_lock(b);
}
transaction_manager::read_ref
transaction_manager::read_lock(block_address b, validator v)
{
return bm_->read_lock(b, v);
}
void
transaction_manager::add_shadow(block_address b)
{
shadows_.insert(b);
}
void
transaction_manager::remove_shadow(block_address b)
{
shadows_.erase(b);
}
bool
transaction_manager::is_shadow(block_address b) const
{
return shadows_.count(b) > 0;
}
void
transaction_manager::wipe_shadow_table()
{
shadows_.clear();
}
//----------------------------------------------------------------