Change in vdsm[master]: Invalidate filters on HSMs before rescanning extended VG

[Dan Kenigsberg]

Dan Kenigsberg has posted comments on this change.

Change subject: Invalidate filters  on HSMs before rescanning extended VG
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Patch Set 18: Code-Review-1

I am reluctant to merge, since I have understood (guess how) that this patch does not eliminate the race between extendVG (on the SPM) and domainMonitor (on an HSM).

After getDevVis is called on HSM (but before extendVG), the domainMonitor can sample the storage, and re-create an exact same filter.

Later, after the vg is extended, the domainMonitor would report it as "partial" again.

We should find a way to halt domainMonitor on HSMs before a vgextend, and restart it later. Alternatively, Engine should ignore false negative results during that period.

Alter