TrueNAS 25.x mounts /usr as a read-only filesystem. Writing
sitecustomize.py to site-packages and patching the Angular bundle
both fail with EROFS.
Fix: mount a writable overlayfs on each target directory before
writing to it. Upper/work dirs live in /run (tmpfs), so overlays are
volatile per boot and are recreated by apply.sh on every PREINIT run
before middlewared starts.
apply.sh:
- Add _ensure_writable(dir, tag): probes writability; mounts overlay
in /run/truecloud-{tag}-{upper,work} if the directory is read-only;
detects if the overlay is already mounted (idempotent)
- Call _ensure_writable before site-packages writes (tag "sc")
- Detect webui dir with bash loop; call _ensure_writable before
patch_ui.py (tag "ui") — non-fatal if mount fails
uninstall.sh:
- Add overlay unmounting section after file restoration and before
rm -rf, so the lower layer's originals are exposed immediately
- Move _restore_failed exit 1 to after unmount so overlays are
cleaned up even on partial failure
- Update "no backup files" message for immutable OS context
flan
3afca7075e