[libvirt] [PATCH v4] Ignore backing file errors in FS storage pool

[Philipp Hahn]

Hello Daniel, hello Eric,

Ping?

Am Dienstag 01 März 2011 16:48:20 schrieb Philipp Hahn:
> Currently a single storage volume with a broken backing file will disable
> the whole storage pool. This can happen when the backing file is on some
> unavailable network storage or if the backing volume is deleted, while the
> storage volumes using it remain.
> Since the storage pool can not be re-activated, re-creating the missing
> or deleting the now useless volumes using libvirt only is not possible.
>
> Fixing this is a little bit tricky:
> 1. virStorageBackendProbeTarget() only detects the missing backing file,
>    if the backing file format is not explicitly specified. If the
>    backing file is created using
> 	   kvm-img create -f qcow2 -o backing_fmt=qcow2,backing_file=... ...
>    no error is detected at this stage.
>    The new return code -3 signals that the backing file could not be
>    opened.
> 2. The backingStore.format must be >= 0, since values < 0 would break
>    virStorageVolTargetDefFormat() when dumping the XML data such as
>        <format type='...'/>
>    Because of this the format is faked as VIR_STORAGE_FILE_RAW.
> 3. virStorageBackendUpdateVolTargetInfo() always opens the backing file
>    and thus always detects a missing backing file.
>    Since it "only" updates the capacity, allocation, owner, group, mode
>    and SELinux label, just ignore errors at this stage, print an error
>    message and continue.
> 4. Using vol-dump on a broken volume still doesn't work, but at leas
>    vol-destroy and pool-refresh do work now.

Any news on the review front for this issue? I know the patch might not be the 
perfect solution, but without any comment I don't know how to proceed or 
which part I should improve.

Sincerely
Philipp Hahn
-- 
Philipp Hahn           Open Source Software Engineer      hahn at univention.de
Univention GmbH        Linux for Your Business        fon: +49 421 22 232- 0
Mary-Somerville-Str.1  28359 Bremen                   fax: +49 421 22 232-99
                                                   http://www.univention.de/
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