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docs/pre12-batch-01.md

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+# Pre12 Batch 01
+
+This batch aligns the planned in-memory NID, block-number, and byte-offset
+declarations with the existing `erofs_nid_t`, `erofs_blk_t`, and
+`erofs_off_t` aliases.
+
+The source whitelist was limited to eight fields in `internal.h`, the
+`erofs_iloc`, `erofs_nid_is_valid`, `erofs_read_inode`, and `erofs_vfs_hash`
+declarations and definitions, and the byte-offset parameters of
+`erofs_bread`, `erofs_read_physical`, and `erofs_read_metadata`.
+
+All three aliases are direct `uint64_t` typedefs.  Static assertions confirmed
+that each is an unsigned, 8-byte type with the same alignment and exact C type
+compatibility as `uint64_t`.  Consequently every replaced field has identical
+size and alignment, so both structure sizes, alignments, field order, and all
+target `offsetof` values are unchanged.  Function parameter and return ABI
+representations are also unchanged, and the vnode hash still consumes the
+same complete 8-byte NID object.
+
+The source diff is limited to the planned fields, function declarations and
+definitions, and necessary local declaration splits.  No expressions, field
+order, on-disk types, control flow, error handling, or formatting outside
+those declarations changed.
+
+Validation used exact declaration inventory checks, token-diff inspection,
+declaration/definition signature comparison, arithmetic and hash review,
+compile-time type assertions, and `git diff --check`.  No planned point was
+skipped and no out-of-scope candidate was changed.  No build, QEMU, smoke,
+feature, or other dynamic test was run.