ubuntu-installer/partman does not properly detect partitions on FBA device

------- Comment From <email address hidden> 2016-12-15 10:07 EDT-------
Canonical, please assign to correct component within LP. Thx

Default Comment by Bridge

This ticket is a replacement to LP 1578232 which was a bit screwed up ...

Please excuse my ignorance, but I am working under the assumption that FBA devices should be partitioned using DASD partitioning table just like the ECKD drives (using fdasd tool). If this is wrong, and e.g. ms-dos partition table should be used for FBA devices, we need to change the logic that decides which partitioning tables to use in the installer.

I can reproduce this bug, in a sense that kernel manages to read DASD partitioning table, and partitions, off FBA device including volume label, yet userspace tools parted and fdasd cannot.

syslog:
Jan 11 07:07:27 kernel: [ 156.679393] dasd-fba 0.0.0104: New FBA DASD 9336/10 (CU 6310/80) with 59025 MB and 512 B/blk
Jan 11 07:07:27 kernel: [ 156.682792] dasdb:VOL1/ 0X0104: dasdb1 dasdb2

# cat /proc/dasd/devices
0.0.0104(FBA ) at ( 94: 4) is dasdb : active at blocksize: 512, 120884827 blocks, 59025 MB

# cat /proc/partitions | grep dasdb
  94 4 60442413 dasdb
  94 5 585920 dasdb1
  94 6 59856256 dasdb2

# fdasd -p /dev/dasdb

fdasd error: Unsupported disk type
/dev/dasdb is not an ECKD disk! This disk type is not supported!

# fdasd -f -p /dev/dasdb
reading volume label ..:
Cannot show requested information because the disk label block is invalid
exiting...

# parted /dev/dasdb print
Model: IBM S390 DASD drive (dasd)
Disk /dev/dasdb: 61.9GB
Sector size (logical/physical): 512B/512B
Partition Table: dasd
Disk Flags:

Number Start End Size File system Flags
 1 1024B 61.9GB 61.9GB

------- Comment From <email address hidden> 2017-01-11 10:18 EDT-------
Hi Dimitri,

FBA DASDs must be treated differently from regular DASDs, i.e. to create a partition, you should use fdisk, parted etc. and not fdasd.

(In reply to comment #8)
> Please excuse my ignorance, but I am working under the assumption that FBA
> devices should be partitioned using DASD partitioning table just like the
> ECKD drives (using fdasd tool). If this is wrong, and e.g. ms-dos partition
> table should be used for FBA devices, we need to change the logic that
> decides which partitioning tables to use in the installer.
>
> I can reproduce this bug, in a sense that kernel manages to read DASD
> partitioning table, and partitions, off FBA device including volume label,
> yet userspace tools parted and fdasd cannot.
>
> syslog:
> Jan 11 07:07:27 kernel: [ 156.679393] dasd-fba 0.0.0104: New FBA DASD
> 9336/10 (CU 6310/80) with 59025 MB and 512 B/blk
> Jan 11 07:07:27 kernel: [ 156.682792] dasdb:VOL1/ 0X0104: dasdb1 dasdb2
>
> # cat /proc/dasd/devices
> 0.0.0104(FBA ) at ( 94: 4) is dasdb : active at blocksize: 512,
> 120884827 blocks, 59025 MB
>
> # cat /proc/partitions | grep dasdb
> 94 4 60442413 dasdb
> 94 5 585920 dasdb1
> 94 6 59856256 dasdb2
>
> # fdasd -p /dev/dasdb
>
> fdasd error: Unsupported disk type
> /dev/dasdb is not an ECKD disk! This disk type is not supported!
>
> # fdasd -f -p /dev/dasdb
> reading volume label ..:
> Cannot show requested information because the disk label block is invalid
> exiting...
>
> # parted /dev/dasdb print
> Model: IBM S390 DASD drive (dasd)
> Disk /dev/dasdb: 61.9GB
> Sector size (logical/physical): 512B/512B
> Partition Table: dasd
> Disk Flags:
>
> Number Start End Size File system Flags
> 1 1024B 61.9GB 61.9GB

Hello,

I think I should add a condition in partman-partitioning that checks /proc/dasd/devices to see if the drive with `dasd` label is FBA, and if so, fallback to msdos partioning table. I'm not sure if FBA drive via virtio in KVM has /proc/dasd/devices with the right information or not. I guess using BIODASDINFO ioctl is better.

However, shouldn't the GNU parted use BIODASDINFO ioctl and report/export dasd_info.type such that partman-partioning can use that? Or e.g. not set `dasd` label when dasd_info.type != "ECKD" (same logic as fdasd)?

Regards,

Dimitri.

------- Comment From <email address hidden> 2017-01-12 07:23 EDT-------
Unfortunately, the term dasd is overloaded as it describes a) a disk device type in terms of access method (more comparable with SCSI or IDE) and b) the format of the disk in a misleading manner (instead of dasd it should rather be called eckd).
This becomes quite obvious by looking at KVM: here the device typein the guest is virtio_blk, whereas the data format is determined by the device type in the host, which can be an ECKD DASD. BIODASDINFO won't work in this case because it needs the dasd driver.
The way I'd suggest to attack this would be in partman-base rather than in partman-partitioning, because the former package determines the label type to be written. I.e. one could check whether the disk is of type dasd_fba and in this case not request a dasd label.
Alternatively, one could consider changing parted, but this might be more complex/error prone.

This bug was fixed in the package partman-partitioning - 114ubuntu2

---------------
partman-partitioning (114ubuntu2) zesty; urgency=medium

  * DASD-FBA drives should still use msdos partition table, and not dasd
    one. LP: #1650300

 -- Dimitri John Ledkov <email address hidden> Thu, 12 Jan 2017 12:36:28 +0000

"I.e. one could check whether the disk is of type dasd_fba and in this case not request a dasd label." but how would one do that in partman-base? given that parted does report "dasd" type to partman. Note that partman-partitioning ultimately decides what the default partition table is, and users can override that. What I have uploaded is a whitelist, thus if somebody export FBA via virtio, it will result in using dasd partition table =(. However, the combination of FBA and KVM is niche no? (as in running kvm, in z/VM, with FBA pass-through virtio devices)

------- Comment From <email address hidden> 2017-01-12 10:39 EDT-------
My point of view was more a structural one: the parameters for the "make label" operation are assembled in partman-base and the extra check for FBA could be done there as well. But that may just be a matter of taste.

And the comment about virtio and DASD may have been misleading, I wanted to point out that using DASD-specific ioctls as only means of identifying DASD type disks would break the (ECKD) DASD detection in KVM.

And the current DASD detection in KVM, detects both ECKD and FBA as the same thing? or does it manage to make a distinction? I'll need to test that.

Default Comment by Bridge

Default Comment by Bridge

Hello bugproxy, or anyone else affected,

Accepted partman-partitioning into yakkety-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/partman-partitioning/112ubuntu1.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed.Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

Hello bugproxy, or anyone else affected,

Accepted partman-partitioning into xenial-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/partman-partitioning/110ubuntu4.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed.Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

Testing yakkety d-i 20101020ubuntu483.1 with apt-setup/proposed=true with partman-partitioning_112ubuntu1.1_s390x.udeb. Successful.

Testing xenial d-i 20101020ubuntu451.9 with apt-setup/proposed=true with partman-partitioning_110ubuntu4.1_s390x.udeb. Successful.

The verification of the Stable Release Update for partman-partitioning has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

This bug was fixed in the package partman-partitioning - 112ubuntu1.1

---------------
partman-partitioning (112ubuntu1.1) yakkety; urgency=medium

  * DASD-FBA drives should still use msdos partition table, and not dasd
    one. LP: #1650300

 -- Dimitri John Ledkov <email address hidden> Thu, 12 Jan 2017 16:51:03 +0000

This bug was fixed in the package partman-partitioning - 110ubuntu4.1

---------------
partman-partitioning (110ubuntu4.1) xenial; urgency=medium

  * DASD-FBA drives should still use msdos partition table, and not dasd
    one. LP: #1650300

 -- Dimitri John Ledkov <email address hidden> Thu, 12 Jan 2017 16:56:44 +0000

------- Comment From <email address hidden> 2017-01-25 06:45 EDT-------
IBM Bugzilla -> closed