[parted-devel] [Parted-maintainers] Debian Bug #578097: No support for CMS-formatted disks

[Stephen Powell]

Praise the Lord!  I do believe I've got it now.  Parted now supports all
DASD types (CKD and FBA), drivers (ECKD, FBA, and DIAG) and disk formats
(CDL, LDL, and CMS) that are supported by the Linux kernel on the s390
architecture.  I even have that last remaining case covered: old LDL
disk format (pre version 2) on CKD DASD using the DIAG driver.  It was
the only case left that required knowledge of device geometry when device
geometry was bogus.  disk->dev->length proved to be the key to solving
that problem.  This is the size of the disk in 512-byte sectors and is
correct even when device geometry (cylinders, heads, and sectors per
track) is bogus.

Only CDL format on CKD DASD using the ECKD driver is supported for
actual partition editing (create, delete, move, re-size, etc.)  The
other combinations are read-only.  That is, parted recognizes the
preexisting partition, but it cannot be deleted, moved, or re-sized.
New partitions cannot be added either.  You should be able to make
a file system on the pre-existing partition with parted though.

Speaking of file systems, I think there may be a bug in the file system
code.  I haven't touched that portion of the code, but when I issue
a command like

   parted /dev/dasde print 1

for a disk on which a file system has been created on the partition
directly by Linux (such as with mke2fs) I get funny errors.  (For
some reason I have to take the device offline and bring it back
online again after I run mke2fs in order for parted to see the file
system.)  For example, the output of the above command is

   Error: File system has an incompatible feature enabled.  Compatible
   features are has_journal, dir_index, filetype, sparse_super, and
   large_file.  Use tune2fs or debugfs to remove features.

I just made this file system seconds ago.  And it was made with a
native file system tool.  How can it be invalid already?
Someone ought to take a look at that.  I have the same problem with
the original code; so I don't think I broke it.

I intend to put the changed code through some fairly extensive
final tests next week, and after that I will upload a unified diff
with all my changes.  It will, however, have my original changes
published via the context diffs as a prerequisite.  Sorry.  I'm
a novice at this.  In fact, my only qualifications for making these
changes seems to be that (a) I need the new functionality, and
(b) I have the necessary hardware with which to test.  Programming
skills, Linux knowledge, C knowledge, knowledge of "how things are
done procedurally", etc. are probably all sub-par.  I ask for your
patience and forbearance as I slowly and painfully learn all that
stuff.

-- 
  .''`.     Stephen Powell    
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