140 lines
2.6 KiB
C++
140 lines
2.6 KiB
C++
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#include <algorithm>
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#include <cerrno>
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#include <cstring>
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#include <cstddef>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <unistd.h>
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#include <Cache/MappedBlockCache.h>
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#include <Device/BlockDevice.h>
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#include <Common/Exception.h>
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#include <POSIX/Exception.h>
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using namespace Device;
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BlockCachePointer MappedBlockCache::Create(BlockDevicePointer device, void *data)
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{
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//return BlockCachePointer(new MappedBlockCache(device, data));
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return MAKE_SHARED(MappedBlockCache, device, data);
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}
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MappedBlockCache::MappedBlockCache(BlockDevicePointer device, void *data) :
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BlockCache(device)
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{
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_data = (uint8_t *)data;
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_dirty = false;
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}
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MappedBlockCache::~MappedBlockCache()
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{
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if (_dirty) sync();
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}
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void *MappedBlockCache::acquire(unsigned block)
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{
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#undef __METHOD__
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#define __METHOD__ "MappedBlockCache::load"
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if (block >= blocks())
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throw Exception(__METHOD__ ": Invalid block.");
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return _data + block * 512;
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}
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void MappedBlockCache::release(unsigned block, int flags)
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{
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#undef __METHOD__
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#define __METHOD__ "MappedBlockCache::unload"
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// kBlockCommitNow implies kBlockDirty.
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if (flags & kBlockCommitNow)
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{
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sync(block);
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return;
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}
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if (flags & kBlockDirty) _dirty = true;
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}
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void MappedBlockCache::write(unsigned block, const void *vp)
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{
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#undef __METHOD__
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#define __METHOD__ "MappedBlockCache::write"
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if (block >= blocks())
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throw Exception(__METHOD__ ": Invalid block.");
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_dirty = true;
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std::memcpy(_data + block * 512, vp, 512);
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}
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void MappedBlockCache::zeroBlock(unsigned block)
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{
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#undef __METHOD__
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#define __METHOD__ "MappedBlockCache::zeroBlock"
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if (block >= blocks())
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throw Exception(__METHOD__ ": Invalid block.");
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_dirty = true;
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std::memset(_data + block * 512, 0, 512);
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}
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// sync everything.
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void MappedBlockCache::sync()
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{
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_device->sync();
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_dirty = false;
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}
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/*
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*
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* sync an individual page.
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*
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*/
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void MappedBlockCache::sync(unsigned block)
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{
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#undef __METHOD__
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#define __METHOD__ "MappedBlockCache::sync"
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int pagesize = ::getpagesize();
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void *start = _data + block * 512;
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void *end = _data + 512 + block * 512;
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start = (void *)((ptrdiff_t)start / pagesize * pagesize);
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end = (void *)((ptrdiff_t)end / pagesize * pagesize);
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if (::msync(start, pagesize, MS_SYNC) != 0)
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throw POSIX::Exception(__METHOD__ ": msync", errno);
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if (start != end)
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{
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if (::msync(end, pagesize, MS_SYNC) != 0)
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throw POSIX::Exception(__METHOD__ ": msync", errno);
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}
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}
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void MappedBlockCache::markDirty(unsigned block)
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{
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_dirty = true;
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}
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