[Libguestfs] Question: running appliance commands over guest fs (resize2fs -P).

[Richard W.M. Jones]

On Tue, Sep 15, 2015 at 04:31:46PM +0300, Maxim Perevedentsev wrote:
> Hello everyone!
> 
> I am working on resizing qcow2 images using virt-resize+liguestfs.

If you're shrinking, I believe a better way to do this is to sparsify
the image.

> E.g. I when shrinking a partition, I have to resize filesystem using
> resize2fs-size. The problem is that I cannot find out minimal
> partition size (aka resize2fs -P). The only way is calling
> "resize2fs-size 1K", wait for resize2fs to claim "resize2fs: New
> size smaller than minimum (510050)" and parse this output.
> 
> It is known that resize2fs carries out complex calculations (no
> always correct) to get minimal size, so statvfs/tune2fs-l cannot
> help.
> 
> The questions are:
> 1) How to get minimal partition size (equal to resize2fs -P)?

There's no binding for that, but it would be a worthwhile addition to
the API.

> 2) More general, how to execute commands from appliance but make
> them run over image (which may not have anything but filesystem) - I
> saw something like that in source.

Not sure I understand the question?

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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