Immutable files on UFS?

[Garrett Cooper]

Hi all,
    This seems like a bit more than a basic question, but I apologize
if I overlooked anything trivial. Basically I have some paths that
don't seem to be removable. I'm not sure what needs to be done to make
the paths mutable.
    I'm open to any and all suggestions in trying to clear out the
filesystem :).
Thanks!
-Garrett

# uname -a
FreeBSD fbsd-vm.zonarsystems.net 11.0-CURRENT FreeBSD 11.0-CURRENT #2
5dc0f18(atf): Tue Apr  8 18:39:49 PDT 2014
root at fbsd-vm.zonarsystems.net:/usr/obj/usr/src/sys/GENERIC  i386
# whoami
root
# mount | grep /dev/ada0p2
/dev/ada0p2 on / (ufs, local, journaled soft-updates)
# chflags -R 0 /usr/obj~/
# rm -Rf /usr/obj~/
rm: /usr/obj~/usr/src/tmp/usr/lib/engines: Directory not empty
rm: /usr/obj~/usr/src/tmp/usr/lib: Directory not empty
rm: /usr/obj~/usr/src/tmp/usr: Directory not empty
rm: /usr/obj~/usr/src/tmp: Directory not empty
rm: /usr/obj~/usr/src: Directory not empty
rm: /usr/obj~/usr: Directory not empty
rm: /usr/obj~/obj/usr/src/tmp/usr/tests/bin/pkill: Directory not empty
rm: /usr/obj~/obj/usr/src/tmp/usr/tests/bin: Directory not empty
rm: /usr/obj~/obj/usr/src/tmp/usr/tests: Directory not empty
rm: /usr/obj~/obj/usr/src/tmp/usr: Directory not empty
rm: /usr/obj~/obj/usr/src/tmp: Directory not empty
rm: /usr/obj~/obj/usr/src: Directory not empty
rm: /usr/obj~/obj/usr: Directory not empty
rm: /usr/obj~/obj: Directory not empty
rm: /usr/obj~/: Directory not empty
# truss -o log rm -Rf
pjdfstest_0144459825150ee4088883866736d6ed/pjdfstest_5927dfc58a61fcfd500945dc28976d89
rm: pjdfstest_0144459825150ee4088883866736d6ed/pjdfstest_5927dfc58a61fcfd500945dc28976d89:
Operation not permitted
# egrep 'rmdir|unlink' log
unlink("pjdfstest_0144459825150ee4088883866736d6ed/pjdfstest_5927dfc58a61fcfd500945dc28976d89")
ERR#1 'Operation not permitted'

# truss -o log rm -Rf /usr/obj~/usr/src/tmp/usr/lib/engines/
rm: /usr/obj~/usr/src/tmp/usr/lib/engines/: Directory not empty
# find /usr/obj~/usr/src/tmp/usr/lib/engines/ -mindepth 1 | wc -l
       0
# egrep 'rmdir|unlink' log
rmdir(0x2880b100,0x10,0x0,0xbfbfec10,0x0,0x2)    ERR#66 'Directory not empty'