* librbd diff_iterate question
@ 2016-09-14 19:13 Max Yehorov
2016-09-14 20:10 ` Jason Dillaman
0 siblings, 1 reply; 2+ messages in thread
From: Max Yehorov @ 2016-09-14 19:13 UTC (permalink / raw)
To: ceph-devel
Hi,
according to code comments: diff_iterate2 returns the differences
between two versions of an image via a callback, which gets the offset
and length and a flag indicating whether the extent exists.
Now, there are two code paths to calculate diff, one that uses
fast-diff/obj-map and the other which asks osds. It appears that only
fast-diff code path can set "exists" flag to false in the
diff_iterate's callback. Is that the correct assumtion?
thanks!
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: librbd diff_iterate question
2016-09-14 19:13 librbd diff_iterate question Max Yehorov
@ 2016-09-14 20:10 ` Jason Dillaman
0 siblings, 0 replies; 2+ messages in thread
From: Jason Dillaman @ 2016-09-14 20:10 UTC (permalink / raw)
To: Max Yehorov; +Cc: ceph-devel
On Wed, Sep 14, 2016 at 3:13 PM, Max Yehorov <myehorov@skytap.com> wrote:
> It appears that only
> fast-diff code path can set "exists" flag to false in the
> diff_iterate's callback. Is that the correct assumtion?
The fast-diff code path within diff_iterate can set the "exists" flag
to true (1) if the object exists and has been updated since the "from"
snapshot (i.e. there is a delta), otherwise it is set to false (0).
--
Jason
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2016-09-14 20:10 ` Jason Dillaman
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