utils_disk/libvirt_disk: add way to handle disk by path

Partitions in /proc/partitions are not persistent which
can lead to problems when a test checks if a disk was cold
plugged.

Use persistent naming from /dev/disk/by-path which allows
us to easily identify those disks and partitions with
the attached disk by their libvirt <address/>.

Add and update other functions to be compatible with this way
of dealing with partitions.

Signed-off-by: Sebastian Mitterle <[email protected]>

virttest/utils_disk.py

@@ -26,6 +26,7 @@
 
 from virttest import error_context
 from virttest import utils_numeric
+from virttest import utils_misc
 from virttest import remote
 
 PARTITION_TABLE_TYPE_MBR = "msdos"
@@ -1083,6 +1084,19 @@ def linux_disk_check(session, did):
         clean_partition_linux(session, did)
 
 
+def get_parts_list_by_path(session=None):
+    """
+    Get all partitions as listed on /dev/disk/by-path
+    """
+    err, out = utils_misc.cmd_status_output("ls /dev/disk/by-path",
+                                            shell=True, session=session)
+    if err:
+        raise exceptions.TestError("Failed to list partitions in /dev/disk/by-path")
+    r = out.split()
+    logging.debug("Partitions by path: %s", r)
+    return r
+
+
 def get_parts_list(session=None):
     """
     Get all partition lists.
@@ -1118,6 +1132,23 @@ def get_added_parts(session, old_parts):
     return added_parts
 
 
+def get_added_parts_by_path(session, old_parts):
+    """
+    Get newly added partition list comparing to old parts
+    Uses the information below /dev/disk/by-path instead
+    of /proc/partitions
+
+    :param session: the vm session
+    :param old_parts: list, the old partition list as listed
+                      below /dev/disk/by-path
+    :return: list, the newly added partition list
+    """
+    new_parts = get_parts_list_by_path(session)
+    added_parts = list(set(new_parts).difference(set(old_parts)))
+    LOG.info("Added parts:%s", added_parts)
+    return added_parts
+
+
 def get_first_disk(session=None):
     """
     Get the first disk device on host or guest

virttest/utils_libvirt/libvirt_disk.py

@@ -588,21 +588,22 @@ def fill_null_in_vm(vm, target, size_value=500):
         raise exceptions.TestError(str(e))
 
 
-def check_virtual_disk_io(vm, partition):
+def check_virtual_disk_io(vm, partition, path="/dev/%s"):
     """
     Check if the disk partition in vm can be normally used.
 
     :param vm: Vm instance
     :param partition: the disk partition in vm to be checked.
+    :param path: the folder path for the partition
     :return: if the disk can be used, return True
     """
     session = None
     try:
         session = vm.wait_for_login()
-        cmd = ("fdisk -l /dev/{0} && mkfs.ext4 -F /dev/{0} && "
-               "mkdir -p test && mount /dev/{0} test && echo"
+        cmd = ("fdisk -l && mkfs.ext4 -F {0} && "
+               "mkdir -p test && mount {0} test && echo"
                " teststring > test/testfile && umount test"
-               .format(partition))
+               .format(path % partition))
         status, output = session.cmd_status_output(cmd)
         LOG.debug("Disk operation in VM:\nexit code:\n%s\noutput:\n%s",
                   status, output)