On 06/11/2015 01:09 PM, Hugo Mills wrote:
On Thu, Jun 04, 2015 at 05:17:25PM -0400, Josef Bacik wrote:
Neil Horman pointed out a problem where if he did something like this
receive A
snap A B
change B
send -p A B
and then on another box do
recieve A
receive B
the receive B would fail because we use the UUID of A for the clone sources for
B. This makes sense most of the time because normally you are sending from the
original sources, not a received source. However when you use a recieved subvol
its UUID is going to be something completely different, so if you then try to
receive the diff on a different volume it won't find the UUID because the new A
will be something else. The only constant is the received uuid. So instead
check to see if we have received_uuid set on the root, and if so use that as the
clone source, as btrfs receive looks for matches either in received_uuid or
uuid. Thanks,
While this deals with Neil's problem, there's a few other use-cases
that people have been asking for that (I think) it won't deal with.
I think ultimately we should be sending all three of the parent
UUID, the parent's Received UUID (if it exists), and the parent's
Parent UUID. That would have to go in the FARv2 update, though.
However, since this patch doesn't rule out the above happening at
some future date, and I think it'll do the job as described above,
Yeah I'd like to send more information so we can better find the UUID
we're looking for, but I think at least trying to keep a consistent UUID
we carry around would be good. Received UUID mostly accomplishes this,
I'd like to know what other use cases aren't working so we can think
about what we need to do for them. Thanks,
Josef
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