- Ownership is applied before permissions: chown clears setuid/setgid,
so saving a 06755 file left it 0755.
- The umask is read once during static initialisation. Reading it at
save time needed umask(0)/umask(old), briefly changing it for the swap
writer thread creating files.
- Before rewriting a hard-linked file in place, the new content is
written and synced to a copy beside it; if the in-place write fails
(ENOSPC, EIO) the copy is kept and named in the error.
- Journal headers also record a CRC-32 of the base file (flags bit 1,
bytes 40..43). A changed mtime with the same size and content
(touch, checkout back and forth) no longer marks a journal stale.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015rcVQiiWyTzoNrsvLSaAfB
Claude
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