On Thu, 28 Oct 2010 12:26:00 -0400 (EDT), Jim Meyering wrote: > Thank you. > I confirmed that it applies and doesn't cause any trouble on x86_64/linux. > I'll actually look at the code and make sure tests pass on an > s390x next week, assuming I can get access. > > Speaking of tests, can you outline a couple > that will exercise some (more the merrier) of this new code?
I primarily use the print command for testing. For example, suppose that device number 0200 is /dev/dasda. I would issue the command parted /dev/dasda unit s print free and compare the starting sector and number of sectors to the output of cat /sys/bus/ccw/devices/0.0.0200/block/dasda/dasda1/start and cat /sys/bus/ccw/devices/0.0.0200/block/dasda/dasda1/size to check to see if parted is calculating the size of the partition the same way as the Linux kernel does. (Believe it or not I found a bug in the Linux kernel this way about five months ago. See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=582281 for details.) The key, of course, is to try as many different combinations of DASD type (CKD and FBA), DASD format (CDL, LDL, CMS non-reserved, and CMS reserved), and DASD driver (ECKD, FBA, and DIAG) as possible. Only the following combinations are supported by the Linux kernel: DASD type DASD format DASD driver --------- ----------- ----------- CKD CDL ECKD CKD LDL ECKD CKD LDL DIAG CKD CMS-NR ECKD CKD CMS-NR DIAG CKD CMS-R ECKD CKD CMS-R DIAG FBA CMS-NR FBA FBA CMS-NR DIAG FBA CMS-R FBA FBA CMS-R DIAG The DIAG driver can only be used when Linux for s390 is running in a virtual machine under z/VM. And the CMS DASD format can only be created by the CMS operating system, which only runs in a virtual machine under z/VM. So nine of the eleven combinations will require z/VM in some way to test them. parted only supports the first combination for read-write operations. The others are supported read-only. By read-only I mean that a new partition cannot be created, the pre-existing partition cannot be deleted, and the pre-existing partition cannot be moved or changed in size. I do not mean that write operations cannot be performed on the data in the partition. They can. For example, a file system or swap space can be created on the partition. The other variant is the block size of the disk. The block size can be 512, 1024, 2048, or 4096. With 11 combinations of DASD type, DASD format, and driver times 4 possible block sizes that yields 44 possible configurations for exhaustive testing. And that does not take into account variations in the size of the disk. I have tested all combinations that do not involve the CDL format, since I didn't touch that code. One thing I did discover during testing: it is essential to take the disk offline echo 0 >/sys/bus/ccw/devices/0.0.nnnn/online where nnnn is the device number, and bring it online again echo 1 >/sys/bus/ccw/devices/0.0.nnnn/online after changing the block size of the disk. Simply refreshing the operating system's view of the partition table is not sufficient. (Of course, all partitions on the disk that are currently mounted must be unmounted before the disk can be taken offline; but you wouldn't normally re-format the disk while partitions are mounted anyway. Similarly, any active swap spaces on the disk must be deactivated before taking the disk offline.) -- .''`. Stephen Powell : :' : `. `'` `- -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
