[ovirt-devel] Re: [VDSM] TestMount.testSymlinkMount failing

On Wed, Nov 7, 2018 at 6:27 AM Germano Veit Michel <germano(a)redhat.com&gt; wrote: > Hi, > > I have seen CI failing with some "random" errors which makes submitting a > series of patches a bit annoying, as some patch always fails with some > error, then next run another patch fails. > > One of these problems is TestMount.testSymlinkMount. Looks like its > getting EBUSY when doing a rmdir. So probably something still using it? > > =================================== FAILURES =================================== > __________________________ TestMount.testSymlinkMount __________________________ > > args = (<storage.mount_test.TestMount testMethod=testSymlinkMount>,) > kwargs = {} > > @wraps(f) > def wrapper(*args, **kwargs): > if cond: > raise SkipTest(reason) > > return f(*args, **kwargs) > > testValidation.py:274: > _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ > testValidation.py:333: in wrapper > return f(*args, **kwargs) > storage/mount_test.py:167: in testSymlinkMount > m.umount() > /usr/lib64/python2.7/contextlib.py:35: in __exit__ > self.gen.throw(type, value, traceback) > testlib.py:218: in namedTemporaryDir > shutil.rmtree(tmpDir) > /usr/lib64/python2.7/shutil.py:261: in rmtree > rmtree(fullname, ignore_errors, onerror) > /usr/lib64/python2.7/shutil.py:270: in rmtree > onerror(os.rmdir, path, sys.exc_info()) > _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ > > path = '/var/tmp/tmpOYMiHx/mountpoint', ignore_errors = False > onerror = <function onerror at 0x7fd68afc9938> > > def rmtree(path, ignore_errors=False, onerror=None): > """Recursively delete a directory tree. > > If ignore_errors is set, errors are ignored; otherwise, if onerror > is set, it is called to handle the error with arguments (func, > path, exc_info) where func is os.listdir, os.remove, or os.rmdir; > path is the argument to that function that caused it to fail; and > exc_info is a tuple returned by sys.exc_info(). If ignore_errors > is false and onerror is None, an exception is raised. > > """ > if ignore_errors: > def onerror(*args): > pass > elif onerror is None: > def onerror(*args): > raise > try: > if os.path.islink(path): > # symlinks to directories are forbidden, see bug #1669 > raise OSError("Cannot call rmtree on a symbolic link") > except OSError: > onerror(os.path.islink, path, sys.exc_info()) > # can't continue even if onerror hook returns > return > names = [] > try: > names = os.listdir(path) > except os.error, err: > onerror(os.listdir, path, sys.exc_info()) > for name in names: > fullname = os.path.join(path, name) > try: > mode = os.lstat(fullname).st_mode > except os.error: > mode = 0 > if stat.S_ISDIR(mode): > rmtree(fullname, ignore_errors, onerror) > else: > try: > os.remove(fullname) > except os.error, err: > onerror(os.remove, fullname, sys.exc_info()) > try: > > os.rmdir(path) > E OSError: [Errno 16] Device or resource busy: '/var/tmp/tmpOYMiHx/mountpoint' > > /usr/lib64/python2.7/shutil.py:268: OSError > ----------------------------- Captured stderr call ----------------------------- > 2018-11-07 00:41:55,518 DEBUG (MainThread) [storage.Misc.excCmd] /usr/bin/taskset --cpu-list 0-1 /sbin/mkfs.ext2 -F /var/tmp/tmpOYMiHx/backing.img (cwd None) (commands:68) > 2018-11-07 00:41:55,561 DEBUG (MainThread) [storage.Misc.excCmd] SUCCESS: <err> = 'mke2fs 1.44.2 (14-May-2018)\n'; <rc> = 0 (commands:89) > 2018-11-07 00:41:55,562 INFO (MainThread) [storage.Mount] mounting /var/tmp/tmpOYMiHx/link_to_image at /var/tmp/tmpOYMiHx/mountpoint (mount:204) > 2018-11-07 00:41:55,563 DEBUG (MainThread) [root] /usr/bin/taskset --cpu-list 0-1 /usr/bin/mount -o loop /var/tmp/tmpOYMiHx/link_to_image /var/tmp/tmpOYMiHx/mountpoint (cwd None) (commands:68) > 2018-11-07 00:41:55,598 DEBUG (MainThread) [root] SUCCESS: <err> = ''; <rc> = 0 (commands:89) > 2018-11-07 00:41:55,599 DEBUG (MainThread) [storage.Mount] /var/tmp/tmpOYMiHx/mountpoint mounted: 0.03 seconds (utils:454) > 2018-11-07 00:41:55,599 DEBUG (MainThread) [root] /usr/bin/taskset --cpu-list 0-1 /sbin/udevadm settle --timeout=5 (cwd None) (commands:68) > 2018-11-07 00:41:55,624 DEBUG (MainThread) [root] SUCCESS: <err> = ''; <rc> = 0 (commands:89) > 2018-11-07 00:41:55,625 DEBUG (MainThread) [storage.Mount] Waiting for udev mount events: 0.03 seconds (utils:454) > 2018-11-07 00:41:55,628 INFO (MainThread) [storage.Mount] unmounting /var/tmp/tmpOYMiHx/mountpoint (mount:212) > 2018-11-07 00:41:55,629 DEBUG (MainThread) [root] /usr/bin/taskset --cpu-list 0-1 /usr/bin/umount /var/tmp/tmpOYMiHx/mountpoint (cwd None) (commands:68) > 2018-11-07 00:41:55,658 DEBUG (MainThread) [root] FAILED: <err> = 'umount: /var/tmp/tmpOYMiHx/mountpoint: target is busy.\n'; <rc> = 32 (commands:89) > > The test is doing: 163 m.mount(mntOpts="loop") 164 try: 165 self.assertTrue(m.isMounted()) 166 finally: 167 m.umount() So nothing can use this mount - except systemd, creating a mount unit for every mount created by "mount". If you can reproduce this with calling "mount" and "umount" in a loop, we can open a systemd bug for this. Adding little sleep before unmounting will probably avoid this issue. In production we never unmount write after mount. A possible fix is to use m.umount(force=True, lazy=True) - this is how we unmount file based storage mounts in lib/vdsm/storage/storageServer.py: 201 def disconnect(self): 202 self._mount.umount(True, True) Nir