1) make the program return return success (0) if the symlink should be
created, and return failure (!0) if not
2) return only the plain-text symlinks strings; no "SYMLINK="
assignment
However, that would require updating the drbdadm program output as well as the udev rule.
Alternately, the drbd udev rule could be refactored, so it didn't place multiple symlinks into an env variable; for example, it could do this:
PROGRAM= "/usr/sbin/ drbdadm sh-udev minor-%m", SYMLINK="$result",
GOTO="have_symlink"
however, it would need to:
1) make the program return return success (0) if the symlink should be
created, and return failure (!0) if not
2) return only the plain-text symlinks strings; no "SYMLINK="
assignment
However, that would require updating the drbdadm program output as well as the udev rule.