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Disk: Fix improper offset calculation

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This would cause an underflow previously
This commit is contained in:
Paul Hollinsky
2022-02-25 01:14:57 -05:00
parent 242c7259ac
commit 241502c2a2
2 changed files with 13 additions and 4 deletions
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disk/diskreaddriver.cpp
+6 -1
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@@ -24,7 +24,12 @@ optional<uint64_t> ReadDriver::readLogicalDisk(Communication& com, device_eventh
while(blocksProcessed < blocks && timeout >= std::chrono::milliseconds::zero()) {
const uint64_t currentBlock = startBlock + blocksProcessed;
const uint64_t intoOffset = std::max<uint64_t>((blocksProcessed * idealBlockSize) - posWithinFirstBlock, 0);
uint64_t intoOffset = blocksProcessed * idealBlockSize;;
if(intoOffset < posWithinFirstBlock)
intoOffset = 0;
else
intoOffset -= posWithinFirstBlock;
const uint32_t posWithinCurrentBlock = (blocksProcessed ? 0 : posWithinFirstBlock);
uint32_t curAmt = idealBlockSize - posWithinCurrentBlock;
const auto amountLeft = amount - ret.value_or(0);
disk/diskwritedriver.cpp
+7 -3
View File
@@ -32,7 +32,12 @@ optional<uint64_t> WriteDriver::writeLogicalDisk(Communication& com, device_even
while(blocksProcessed < blocks && timeout >= std::chrono::milliseconds::zero()) {
const uint64_t currentBlock = startBlock + blocksProcessed;
const uint64_t fromOffset = std::max<uint64_t>((blocksProcessed * idealBlockSize) - posWithinFirstBlock, 0);
uint64_t fromOffset = blocksProcessed * idealBlockSize;
if(fromOffset < posWithinFirstBlock)
fromOffset = 0;
else
fromOffset -= posWithinFirstBlock;
const uint32_t posWithinCurrentBlock = (blocksProcessed ? 0 : posWithinFirstBlock);
uint32_t curAmt = idealBlockSize - posWithinCurrentBlock;
const auto amountLeft = amount - ret.value_or(0);
@@ -54,8 +59,7 @@ optional<uint64_t> WriteDriver::writeLogicalDisk(Communication& com, device_even
const bool useAlignedWriteBuffer = (posWithinCurrentBlock != 0 || curAmt != idealBlockSize);
if(useAlignedWriteBuffer) {
if(alignedWriteBuffer.size() < idealBlockSize)
alignedWriteBuffer.resize(idealBlockSize);
alignedWriteBuffer = atomicBuffer;
memcpy(alignedWriteBuffer.data() + posWithinCurrentBlock, from + fromOffset, curAmt);
}