On Wed, Aug 07, 2013 at 11:13:53AM +0200, Zdenek Kabelac wrote: > Dne 6.8.2013 19:37, Bastian Blank napsal(a): > >I hold the cow device open so it will run into the error condition: > >| $ sleep 100 < /dev/mapper/vg-test_snap-cow& > You are breaking the lvm2 logic thus pushing the code to go through > unexpected error code path - user is never supposed to open so > called 'private' /dev/mapper/ devices. I'm a developer and use it to trigger an error condition. Please don't start with that crap about what a user should or should not do. > >Then try to remove the LV: > >| $ lvremove vg/test_snap > With upstream lvm2 code - there is embedded 'retry' loop - so the removal > should be retried for couple times (controllable by lvm.conf). Please show that it actually does anything in this case. This is no condition that goes away, but a logic bug. > That's because udev WATCH rule might be fired basically anytime > after close of device opened in write mode - so it may happen lvm2 > checks device is not opened and could be removed, but the udev WATCH > rules opens temporarily device and lvm2 then fails to remove device, > which has been previously detected as unused. There is not udevd running! Please explain how udev can be a problem in this case. > There has been bug affecting cluster usage of exclusive snapshots in > pre .99 version - the order of taking locks for devices was not > correct, and if there > has been clvmd restart during snapshot - it has caused some problems. Did you actually read the code? At least I can clearly see that the error logic is broken. > But for current (.99) code - in normal case the operation should > work properly. For any unpredictable errors - lvm2 command should > print error message and it's up-to admin to fix dangling device and > table entries. It is up to LVM to not break the system with suspended devices. Bastian -- Insufficient facts always invite danger. -- Spock, "Space Seed", stardate 3141.9 _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
