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

On Wed, Nov 7, 2018 at 9:34 PM Nir Soffer <nsoffer(a)redhat.com&gt; wrote: > 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 > Thanks Nir! I'll see if I can reproduce it next week. I have only seen this one on FC28, so it could be a FC28 bug. Yesterday the rebase CI also failed on 2 patches, but the errors were different and I did not have time to investigate.