fiemap: use hint index in get_extent to avoid O(n*m) extent lookups - #399
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zorbathut wants to merge 1 commit into
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fiemap: use hint index in get_extent to avoid O(n*m) extent lookups#399zorbathut wants to merge 1 commit into
zorbathut wants to merge 1 commit into
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During file scanning, get_extent() was called per-block with a linear scan from index 0. For fragmented files with many extents this made process_blocks and process_extents O(blocks * extents) per file. Add a cursor hint to get_extent() that lets callers resume the search from where they left off, turning the common forward-scan case into O(blocks + extents). The hint is validated before use so a stale value silently falls back to a full scan. Co-Authored-By: Claude Opus 4.6 <[email protected]>
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During file scanning, get_extent() was called per-block with a linear scan from index 0. For fragmented files with many extents this made process_blocks and process_extents O(blocks * extents) per file.
Add a cursor hint to get_extent() that lets callers resume the search from where they left off, turning the common forward-scan case into O(blocks + extents). The hint is validated before use so a stale value silently falls back to a full scan.
Co-authored with Claude; improved and verified by me.