[lvm-devel] Aborting. LV mythinpool_tmeta is now incomplete

[Zdenek Kabelac]

Dne 11. 04. 19 v 12:01 Eric Ren napsal(a):
> Hi,
> 
> Another error message is:
> 
> "Failed to suspend thin snapshot origin ..."
> 
> which is in _lv_create_an_lv():
> 
> ```
> 7829         } else if (lv_is_thin_volume(lv)) {
> 7830                 /* For snapshot, suspend active thin origin first */
...

> is active */
> 7843                         if (!update_pool_lv(pool_lv, 0)) {
> 7844                                 stack;
> 7845                                 goto revert_new_lv;
> 7846                         }
> ```
> 
> I don't understand why we need to suspend_lv_origin() and resume_lv_origin() 
> in line?
> 
> And, what reasons might cause this errors?


Hi

When you take any snapshot (thin or thick) the origin LV is suspend with 
fsfreeze operation - so the snapshot is takes with filesystem in 'consistent' 
state.

Otherwise without this - you may end-up with fs junk in your device - as the 
metadata of the filesystem might have stated in page-cache - and no fsck 
utility would be able to figure out what should be correct state of 'fs' 
without losing various amount of data in this operation.


Regards

Zdenek