[dm-devel] 2 TB wraparound on snapshots

[James Bottomley]

On Sat, 2010-06-12 at 14:47 -0400, Phillip Susi wrote:
> Update: it seems this is a problem specific to snapshots.  I used 
> dmsetup to create a linear mapping > 2tb which worked fine.  When 
> writing beyond the 2TB mark to the snapshot, it aliases exceptions 
> starting at sector 0.

So do you have a 64 bit system (like an amd64) that you can try this
with?  If it only occurs on the i686 system, then it's likely a long to
sector conversion bug somewhere in the snapshot code.  If it occurs on
both, there's some 2TB limit coded directly into snapshots.

James