s390: improve/correct DASD support

The long title would be "corrections to partition size and location
calculations for type 1 partitions for s390 dasd".

This could be treated as two separate fixes, one to make corrections
for LDL formatted disks and one to add support for CMS formatted
disks.  I see CMS formatted disks as a variant of LDL formatted
disks, with the additional twist that CMS formatted disks can
be reserved or recomped, which LDL formatted disks cannot be.
This affects the size and location of the partition.

With these patches, parted matches the behavior of the Linux kernel
in recognizing partitions on CMS- and LDL-formatted disks, as documented
in the Linux kernel source code in routine fs/partitions/ibm.c.
Calculation of the metadata has also been changed so that parted will
show no free space on such a disk.  In some cases there are now two
non-contiguous metadata extents: one at the beginning of the disk and
one at the end.

As before, parted only supports CKD DASD using the ECKD driver.
FBA DASD and CKD DASD using the DIAG driver are still not supported.

In my regression testing I have discovered some problems in the area
of recognizing file system options.  However, since I can duplicate
these errors on a version of parted which does not contain my changes,
I have concluded that my changes did not cause this and therefore
this is an unrelated bug.

1 files changed, 55 insertions, 1 deletions

diff --git a/include/parted/vtoc.h b/include/parted/vtoc.h
index 6b41584..d79ce39 100644
--- a/include/parted/vtoc.h
+++ b/include/parted/vtoc.h
@@ -49,6 +49,8 @@ typedef struct cchhb            cchhb_t;
 typedef struct cchh             cchh_t;
 typedef struct labeldate        labeldate_t;
 typedef struct volume_label     volume_label_t;
+typedef struct cms_volume_label cms_volume_label_t;
+typedef struct ldl_volume_label ldl_volume_label_t;
 typedef struct extent           extent_t;
 typedef struct dev_const        dev_const_t;
 typedef struct format1_label    format1_label_t;
@@ -81,7 +83,7 @@ struct __attribute__ ((packed)) labeldate {
 
 struct __attribute__ ((packed)) volume_label {
 	char volkey[4];         /* volume key = volume label                 */
-	char vollbl[4];	        /* volume label                              */
+	char vollbl[4];	        /* volume label ("VOL1" in EBCDIC)           */
 	char volid[6];	        /* volume identifier                         */
 	u_int8_t security;	/* security byte                             */
 	cchhb_t vtoc;           /* VTOC address                              */
@@ -93,6 +95,58 @@ struct __attribute__ ((packed)) volume_label {
 	char res2[4];	        /* reserved                                  */
 	char lvtoc[14];	        /* owner code for LVTOC                      */
 	char res3[29];	        /* reserved                                  */
+        char fudge[4];          /* filler to match length of ldl label       */
+};
+
+struct __attribute__ ((packed)) ldl_volume_label {
+	char vollbl[4];         /* Label identifier ("LNX1" in EBCDIC)       */
+        char volid[6];          /* Volume identifier                         */
+        char res3[69];          /* Reserved field                            */
+        char ldl_version[1];    /* Version number, valid for ldl format      */
+        u_int64_t formatted_blocks;  /* valid when ldl_version >= "2" (in
+                                        EBCDIC)                              */
+};
+
+/*
+ * See:
+ *	z/VM V5R2.0 CMS Planning and Administration
+ *	SC24-6078-01
+ *	What CMS Does / Disk and File Management / Disk File Format
+ * http://publib.boulder.ibm.com/infocenter/zvm/v5r4/topic/com.ibm.zvm.v54.dmsd1/hcsg2b1018.htm
+ */
+struct __attribute__ ((packed)) cms_volume_label {
+	char label_id[4];       /* Label identifier ("CMS1" in EBCDIC)       */
+	char vol_id[6];         /* Volume identifier                         */
+	char version_id[2];     /* Version identifier ("\0\0")               */
+	u_int32_t block_size;   /* Disk block size (512, 1024, 2048 or 4096) */
+	u_int32_t origin_ptr;   /* Disk origin pointer (4 or 5)              */
+	u_int32_t usable_count; /* Number of usable cylinders/blocks         */
+	u_int32_t formatted_count; /* Max # of formatted cylinders/blocks    */
+	u_int32_t block_count;  /* Disk size in CMS blocks                   */
+	u_int32_t used_count;   /* Number of CMS blocks in use               */
+	u_int32_t fst_size;     /* File Status Table (FST) size (64)         */
+	u_int32_t fst_count;    /* Number of FSTs per CMS block              */
+	char format_date[6];    /* Disk FORMAT date (YYMMDDhhmmss)           */
+	char reserved1[2];      /* Reserved fields.
+	                           The low-order bit of the first byte is a
+	                           century flag.  0 = 1900s, 1 = 2000s.
+	                           It is used in conjunction with
+	                           "format_date" to determine the
+	                           four-digit year.                          */
+	u_int32_t disk_offset;  /* Offset in blocks to the start of the
+	                           reserved file when the disk is reserved.
+	                           This is the number of blocks to skip
+	                           before the partition starts.              */
+	u_int32_t map_block;    /* Allocation map block with next hole       */
+	u_int32_t hblk_disp;    /* Displacement in HBLK data of next hole    */
+	u_int32_t user_disp;    /* Disp into user part of allocation map     */
+	u_int32_t open_files;   /* Count of SFS open files for this ADT.
+	                           open_files is not really part of the
+	                           volume label.  It is not used for
+	                           minidisks.                                */
+	char segment_name[8];   /* Name of the shared segment.
+	                           segment_name is not really part of the
+	                           volume label.  It is not stored on disk.  */
 };
 
 struct __attribute__ ((packed)) extent {