Ceph

h1. Export rbd diff between clone and parent

h3. Summary

<pre>

                      s1

parent           O----O-------O

                        |   s2

clone                 O---O----O

                     (f)

</pre>

Currently,  there is no way to export diff betwen s2 and s1, if I forget to create snap (f) when clone image created.

So, this blueprint will add the function to handle it.

h3. Owners

Li Wang (liwang@ubuntukyiln.com)

Yunchuan Wen(yunchuanwen@ubuntukylin.com)

Name

h3. Interested Parties

Name (Affiliation)

Name (Affiliation)

Name

h3. Current Status

when from_snap_id equal zero, librbd::diff_iterate would iterate parent image and gather the parent's diff information.

h3. Detailed Description

1. Add a flag to diff_iterate routine, let it to skip the work of gather parent's diff when the flag is set.

2. Modify rbd export-diff command, like: rbd export-diff foo --from-parent  file

h3. Work items

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