fix(dd): handle O_DIRECT partial block writes #9016
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CodSpeed Performance ReportMerging #9016 will not alter performanceComparing Summary
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naoNao89
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I had a different approach in mind, but your is faster. |
sylvestre
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Fix dd failures with 'IO Error: Invalid input' when using oflag=direct with partial blocks. The issue occurs because O_DIRECT requires proper alignment for all writes, but the final partial block may not meet these requirements. This fix: - Detects EINVAL errors that might be O_DIRECT alignment issues - Temporarily removes O_DIRECT flag using fcntl(F_SETFL) - Retries the write operation without the direct flag - Restores original flags (safer than GNU approach) - Only activates on Linux/Android platforms where O_DIRECT is supported Matches GNU dd behavior discovered through strace analysis.
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hey, got a fix for that dd oflag=direct "invalid input" error on this branch.
addresses issue #9003 where dd fails with 'IO Error: Invalid input' when using oflag=direct with partial blocks.
also related to issue #6078 about gnu test failures. turns out gnu dd temporarily removes the o_direct flag for blocks, but
we weren't doing that. added a simple helper function that detects the alignment error, removes the flag, retries the write, then puts it.
only affects linux/android where o_direct actually works. studied the codebase history, the original file write code
4621557 hasn't changed since so this builds on established patterns.