sync: allow target partition larger than source#406
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deitch merged 1 commit intoJun 1, 2026
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verifyBlockCopy required both partitions' full ReadContents byte count to equal expectedSize, so copying a smaller source into a larger target failed even when the leading bytes matched. That larger-target shape is the normal one when growing a partition before a later swap-and-delete renames it into place. Require each side to hold at least expectedSize bytes, hash exactly expectedSize bytes per side via NewLimitWriter, and drop the equality check on the target's full size. A smaller-than-expected partition is still treated as an error. Closes diskfs#403. Signed-off-by: eriknordmark <erik@zededa.com> Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
deitch
approved these changes
Jun 1, 2026
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Split out of #404 per review feedback.
verifyBlockCopyrequired both partitions' fullReadContentsbytecount to equal
expectedSize, so copying a smaller source into a largertarget failed even when the leading bytes matched — the normal shape
when growing a partition before a later swap-and-delete renames it into
place.
It now requires each side to hold at least
expectedSizebytes, hashesexactly
expectedSizebytes per side viaNewLimitWriter, and drops theequality check on the target's full size. A smaller-than-expected
partition is still an error.
Adds an internal regression test (
TestVerifyBlockCopyTargetLargerThanSource)that copies an 8 MiB source into a 24 MiB target and confirms both the
clean-grow and corrupted-target cases.
Closes #403.