Bug 1665689

Description of problem:

vdsm sos plugin contains this note:

    # locking_type is set to 0 in order to match lvm sos commands. With this
    # configuration we don't take any locks, so we will never block because
    # there is a stuck lvm command.

And then it uses:

    global {
        locking_type=0
        use_lvmetad=0
    }

To run pvs, vgs, lvs.

According to David Teigland, any lvm command may attempt to recover VG metadata, so running these commands without locking in oVirt setup, when
lvm is used over shared storage is risky.

The locking_type was change to 0 in this commit:

commit dc362f0f8e43c30c709700222cb3121908170eff
Author: Ala Hino <ahino>
Date:   Sun Sep 17 13:49:24 2017 +0300

    sos-plugin: Add lvm configuration when executing lvm commands
    
    Add lvm configuration when executing lvm command to gather information.
    This is important because, for example, lvmetada could be enabled and we
    want to disable it when creating the sos report, in addition and as
    recommended, the user can define devices filter and we want to override
    that filter to get all relevant devices.
    In this patch we provide the following lvm config:
    
        global {
            locking_type = 0
            use_lvmetad = 0
        }
    
        devices {
            preferred_names = [ '^/dev/mapper/' ]
            ignore_suspended_devices = 1
            write_cache_state = 0
            disable_after_error_count = 3
            filter = [ 'a|^/dev/mapper/.*|', 'r|.*|' ]
        }
    
    Change-Id: I63f1bcb08a0380537e84d9e3ece36fd876b00635
    Bug-Url: https://bugzilla.redhat.com/1474566
    Signed-off-by: Ala Hino <ahino>

Version-Release number of selected component (if applicable):
v4.20.4

How reproducible:
Not reproducible - the chance that 3 sos commands will conflict with SPM
command is very low, but it is possible.

Steps to Reproduce:
1. Run sosreport on oVirt host while many vms are running and extending thin
   provisioned block disks.

Actual results:
Running sosreport may corrupt VG metadata. See bug 1553133 for similar issue.

Expected results:
sosreport should never modify VG metadata.

Additional info:
Same issue exists in sos lvm2 plugin - the locking_type=0 change was copied
from the lvm2 plugin.
We have upstream issue for sos here:
https://github.com/sosreport/sos/issues/1533