Ryota Ozaki wrote:

Hi,

I've found a regression in using a backing store of a volume (qcow2) in a pool (dir). The following code of 0.6.4 hits my system that works with 0.6.3.

static int createQemuImg(virConnectPtr conn, virStorageVolDefPtr vol, virStorageVolDefPtr inputvol) {

(snip)

const char *inputBackingPath = (inputvol ? inputvol->backingStore.path : NULL);

(snip)

/* XXX: Not strictly required: qemu-img has an option a different * backing store, not really sure what use it serves though, and it * may cause issues with lvm. Untested essentially. */ if (!inputBackingPath || !STREQ(inputBackingPath, vol->backingStore.path)) { virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR, "%s", _("a different backing store can not " "be specified.")); return -1; }

The inputBackingPath will be always NULL when it is called via virStorageBackendFileSystemVolBuild(). (The third argument is passed to that of createQemuImg as it is.)

static int virStorageBackendFileSystemVolBuild(virConnectPtr conn, virStorageVolDefPtr vol) { return _virStorageBackendFileSystemVolBuild(conn, vol, NULL); }

I've addressed the regression with the patch

- if (!inputBackingPath || + if (inputBackingPath &&

However, I'm not sure whether this fix satisfies the aim of the original code. Any idea?

Ahh, that's my fault. The idea is that if cloning a volume, the backing store from the original vol must match the backing store in the new XML. Thanks for looking into this. I think the correct fix is: diff --git a/src/storage_backend_fs.c b/src/storage_backend_fs.c index be6d011..3e26fce 100644 --- a/src/storage_backend_fs.c +++ b/src/storage_backend_fs.c @@ -1255,8 +1255,9 @@ static int createQemuImg(virConnectPtr conn, * backing store, not really sure what use it serves though, and it * may cause issues with lvm. Untested essentially. */ - if (!inputBackingPath || - !STREQ(inputBackingPath, vol->backingStore.path)) { + if (inputvol && + (!inputBackingPath || + !STREQ(inputBackingPath, vol->backingStore.path))) { virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR, "%s", _("a different backing store can not " "be specified.")); <minus the line wrapping> - Cole