[libvirt] Re: [PATCH] Fix raw storage volume creation for allocation < capacity.

Cole Robinson crobinso at redhat.com
Thu Jun 18 19:13:06 UTC 2009


Cole Robinson wrote:
> CreateXMLFrom changes accidentally caused all raw volume creation to be
> fully allocated (as though allocation == capacity). Fix this.
> 
> Also force CreateXMLFrom to maintain the previous behavior: sparseness
> should still be maintained since we search for holes when copying, and the
> clone behavior hasn't been tested with anything but the broken behavior.
> 
> Signed-off-by: Cole Robinson <crobinso at redhat.com>
> ---
>  src/storage_backend_fs.c |    2 +-
>  src/storage_driver.c     |    5 +++++
>  2 files changed, 6 insertions(+), 1 deletions(-)
> 
> diff --git a/src/storage_backend_fs.c b/src/storage_backend_fs.c
> index 0e93e54..c3d66b5 100644
> --- a/src/storage_backend_fs.c
> +++ b/src/storage_backend_fs.c
> @@ -1047,7 +1047,7 @@ static int createRaw(virConnectPtr conn,
>          goto cleanup;
>      }
>  
> -    remain = vol->capacity;
> +    remain = vol->allocation;
>  
>      if (inputfd != -1) {
>          int amtread = -1;
> diff --git a/src/storage_driver.c b/src/storage_driver.c
> index 71e64a4..57a93c1 100644
> --- a/src/storage_driver.c
> +++ b/src/storage_driver.c
> @@ -1377,6 +1377,11 @@ storageVolumeCreateXMLFrom(virStoragePoolPtr obj,
>      if (newvol->capacity < origvol->capacity)
>          newvol->capacity = origvol->capacity;
>  
> +    /* Make sure allocation is at least as large as the destination cap,
> +     * to make absolutely sure we copy all possible contents */
> +    if (newvol->allocation < origvol->capacity;
> +        newvol->allocation = origvol->capacity;
> +

Of course the tweak I make at the last second is completely invalid
syntax :(. Besides needing the obvious fix above, the patch does work as
expected.

Thanks,
Cole

>      if (!backend->buildVolFrom) {
>          virStorageReportError(obj->conn, VIR_ERR_NO_SUPPORT,
>                                "%s", _("storage pool does not support volume creation from an existing volume"));




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