Re: [libvirt] [PATCHv2 01/16] storage: list more file types

When an image has no backing file, using VIR_STORAGE_FILE_AUTO for its type is a bit confusing. Additionally, a future patch would like to reserve a default value for the case of no file type specified in the XML, but different from the current use of -1 to imply probing, since probing is not always safe. Also, a couple of file types were missing compared to supported code: libxl supports 'vhd', and qemu supports 'fat' for directories passed through as a file system. +++ b/src/util/storage_file.c

@@ -335,8 +351,12 @@ qcowXGetBackingStore(char **res, * between the end of the header (QCOW2_HDR_TOTAL_SIZE) * and the start of the backingStoreName (offset) */ - if (isQCow2 && format) - qcow2GetBackingStoreFormat(format, buf, buf_size, QCOW2_HDR_TOTAL_SIZE, offset); + if (isQCow2 && format) { + qcow2GetBackingStoreFormat(format, buf, buf_size, QCOW2_HDR_TOTAL_SIZE, + offset); + if (*format <= VIR_STORAGE_FILE_NONE) + return BACKING_STORE_INVALID; + }