[libvirt] [PATCH v3 5/5] disk: Use virStorageBackendZeroPartitionTable

https://bugzilla.redhat.com/show_bug.cgi?id=1439132 During 'matrix' testing of all possible combinations I found that if device is formated with "gpt" first, then an attempt is made to format using "mac", a startup will fail. Deeper analysis by Peter Krempa indicates that the "mac" table fits into the first block on the disk. Since the GPT disklabel is stored at LBA address 1 it is not overwritten at all. Thus it's apparent that the (blkid) detection tool then prefers GPT over a older disklabel. The GPT disklabel has also a secondary copy at the last LBA of the disk. So, follow the same logic as the logical pool in clearing a 1MB swath at the beginning and end of the device to avoid potential issues with larger sector sizes for the device. Also fixed a minor formatting nit in virStorageBackendDeviceIsEmpty call. Signed-off-by: John Ferlan <jferlan(a)redhat.com&gt; --- src/storage/storage_backend_disk.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/src/storage/storage_backend_disk.c b/src/storage/storage_backend_disk.c index 39371f2..e8f67bb 100644 --- a/src/storage/storage_backend_disk.c +++ b/src/storage/storage_backend_disk.c @@ -491,11 +491,15 @@ virStorageBackendDiskBuildPool(virConnectPtr conn ATTRIBUTE_UNUSED, ok_to_mklabel = true; } else { if (virStorageBackendDeviceIsEmpty(pool->def->source.devices[0].path, - fmt, true)) + fmt, true)) ok_to_mklabel = true; } if (ok_to_mklabel) { + if (virStorageBackendZeroPartitionTable(pool->def->source.devices[0].path, + 1024 * 1024) < 0) + goto error; + /* eg parted /dev/sda mklabel --script msdos */ if (format == VIR_STORAGE_POOL_DISK_UNKNOWN) format = pool->def->source.format = VIR_STORAGE_POOL_DISK_DOS; -- 2.9.3