Tested failing because of missing loop devices

[Nir Soffer]

Hi all,

We see too many failures of tests using loop devices. Is it possible
that we run tests
concurrently on the same slave, using all the available loop devices, or maybe
creating races between different tests?

It seems that we need new decorator for disabling tests on the CI
slaves, since this
environment is too fragile.

Here are some failures:

01:10:33 ======================================================================
01:10:33 ERROR: testLoopMount (mountTests.MountTests)
01:10:33 ----------------------------------------------------------------------
01:10:33 Traceback (most recent call last):
01:10:33   File
"/home/jenkins/workspace/vdsm_master_check-patch-fc23-x86_64/vdsm/tests/mountTests.py",
line 128, in testLoopMount
01:10:33     m.mount(mntOpts="loop")
01:10:33   File
"/home/jenkins/workspace/vdsm_master_check-patch-fc23-x86_64/vdsm/vdsm/storage/mount.py",
line 225, in mount
01:10:33     return self._runcmd(cmd, timeout)
01:10:33   File
"/home/jenkins/workspace/vdsm_master_check-patch-fc23-x86_64/vdsm/vdsm/storage/mount.py",
line 241, in _runcmd
01:10:33     raise MountError(rc, ";".join((out, err)))
01:10:33 MountError: (32, ';mount: /tmp/tmpZuJRNk: failed to setup
loop device: No such file or directory\n')
01:10:33 -------------------- >> begin captured logging << --------------------
01:10:33 Storage.Misc.excCmd: DEBUG: /usr/bin/taskset --cpu-list 0-1
/sbin/mkfs.ext2 -F /tmp/tmpZuJRNk (cwd None)
01:10:33 Storage.Misc.excCmd: DEBUG: SUCCESS: <err> = 'mke2fs 1.42.13
(17-May-2015)\n'; <rc> = 0
01:10:33 Storage.Misc.excCmd: DEBUG: /usr/bin/taskset --cpu-list 0-1
/usr/bin/mount -o loop /tmp/tmpZuJRNk /var/tmp/tmpJO52Xj (cwd None)
01:10:33 --------------------- >> end captured logging << ---------------------
01:10:33
01:10:33 ======================================================================
01:10:33 ERROR: testSymlinkMount (mountTests.MountTests)
01:10:33 ----------------------------------------------------------------------
01:10:33 Traceback (most recent call last):
01:10:33   File
"/home/jenkins/workspace/vdsm_master_check-patch-fc23-x86_64/vdsm/tests/mountTests.py",
line 150, in testSymlinkMount
01:10:33     m.mount(mntOpts="loop")
01:10:33   File
"/home/jenkins/workspace/vdsm_master_check-patch-fc23-x86_64/vdsm/vdsm/storage/mount.py",
line 225, in mount
01:10:33     return self._runcmd(cmd, timeout)
01:10:33   File
"/home/jenkins/workspace/vdsm_master_check-patch-fc23-x86_64/vdsm/vdsm/storage/mount.py",
line 241, in _runcmd
01:10:33     raise MountError(rc, ";".join((out, err)))
01:10:33 MountError: (32, ';mount: /var/tmp/tmp1UQFPz/backing.img:
failed to setup loop device: No such file or directory\n')
01:10:33 -------------------- >> begin captured logging << --------------------
01:10:33 Storage.Misc.excCmd: DEBUG: /usr/bin/taskset --cpu-list 0-1
/sbin/mkfs.ext2 -F /var/tmp/tmp1UQFPz/backing.img (cwd None)
01:10:33 Storage.Misc.excCmd: DEBUG: SUCCESS: <err> = 'mke2fs 1.42.13
(17-May-2015)\n'; <rc> = 0
01:10:33 Storage.Misc.excCmd: DEBUG: /usr/bin/taskset --cpu-list 0-1
/usr/bin/mount -o loop /var/tmp/tmp1UQFPz/link_to_image
/var/tmp/tmp1UQFPz/mountpoint (cwd None)
01:10:33 --------------------- >> end captured logging << ---------------------
01:10:33
01:10:33 ======================================================================
01:10:33 ERROR: test_getDevicePartedInfo (parted_utils_tests.PartedUtilsTests)
01:10:33 ----------------------------------------------------------------------
01:10:33 Traceback (most recent call last):
01:10:33   File
"/home/jenkins/workspace/vdsm_master_check-patch-fc23-x86_64/vdsm/tests/testValidation.py",
line 97, in wrapper
01:10:33     return f(*args, **kwargs)
01:10:33   File
"/home/jenkins/workspace/vdsm_master_check-patch-fc23-x86_64/vdsm/tests/parted_utils_tests.py",
line 61, in setUp
01:10:33     self.assertEquals(rc, 0)
01:10:33 AssertionError: 1 != 0
01:10:33 -------------------- >> begin captured logging << --------------------
01:10:33 root: DEBUG: /usr/bin/taskset --cpu-list 0-1 dd if=/dev/zero
of=/tmp/tmpasV8TD bs=100M count=1 (cwd None)
01:10:33 root: DEBUG: SUCCESS: <err> = '1+0 records in\n1+0 records
out\n104857600 bytes (105 MB) copied, 0.368498 s, 285 MB/s\n'; <rc> =
0
01:10:33 root: DEBUG: /usr/bin/taskset --cpu-list 0-1 losetup -f
--show /tmp/tmpasV8TD (cwd None)
01:10:33 root: DEBUG: FAILED: <err> = 'losetup: /tmp/tmpasV8TD: failed
to set up loop device: No such file or directory\n'; <rc> = 1
01:10:33 --------------------- >> end captured logging << ---------------------

Nir