[sweettea]

In my work identity, we saw a similar problem in our testing, where blkid would cause undesired IO on fresh devices. Eventually, we disabled blkid scanning our device mapper devices upon state changes with a file /etc/udev/59-no-scanning-our-devices.rules containing: ENV{DM_NAME}=="ourdevice", OPTIONS:="nowatch"

Alternately, you could call 'udevadm settle' after device creation before doing anything else, which will let blkid get its desired IO done, I think.

[rleigh]

Yes, we did something similar to disable the triggers. Unfortunately, while this resolved some issues such as being unable to delete LVs which were erroneously in use, it didn't resolve the oopses and kernel freezes which were presumably locking problems or similar inside the kernel.