Subject: [PATCH] libparted: add support for implicit FBA DASD partitions

From: Nageswara R Sastry <rnsastry@linux.vnet.ibm.com>

Fixed Block Access (FBA) DASDs are mainframe-specific disk devices

which are layed out as a sequence of 512-byte sectors. In contrast

to ECKD DASDs, these disks do not require formatting and resemble

the LBA layout of non-mainframe disks. Despite this resemblance,

the Linux kernel applies special handling during partition detection

for FBA DASDs, resulting in a single, immutable partition being

reported.

While actual FBA DASD hardware is no longer available, the z/VM

hypervisor can simulate FBA DASD disks, backed by either ECKD or

SCSI devices.

This patch adds support for recognizing FBA DASD partitions

to parted.

Signed-off-by: Nageswara R Sastry <rnsastry@linux.vnet.ibm.com>

Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>

---

 include/parted/fdasd.h   |    2 +

 libparted/labels/dasd.c  |   63 ++++++++++++++++++++++++++++++++++++++++-------

 libparted/labels/fdasd.c |    5 +++

 3 files changed, 61 insertions(+), 9 deletions(-)

--- a/include/parted/fdasd.h

+++ b/include/parted/fdasd.h

@@ -194,6 +194,8 @@ typedef struct fdasd_anchor {

 	volume_label_t   *vlabel;

 	config_data_t confdata[USABLE_PARTITIONS];

 	struct fdasd_hd_geometry geo;

+	unsigned int label_block;

+	unsigned int FBA_layout;

 } fdasd_anchor_t;

 enum offset {lower, upper};

--- a/libparted/labels/dasd.c

+++ b/libparted/labels/dasd.c

@@ -71,6 +71,7 @@ typedef struct {

 typedef struct {

 	unsigned int format_type;

+	unsigned int label_block;

 	volume_label_t vlabel;

 } DasdDiskSpecific;

@@ -151,6 +152,7 @@ dasd_alloc (const PedDevice* dev)

 	/* CDL format, newer */

 	disk_specific->format_type = 2;

+	disk_specific->label_block = 2;

 	/* Setup volume label (for fresh disks) */

 	snprintf(volser, sizeof(volser), "0X%04X", arch_specific->devno);

@@ -226,7 +228,9 @@ dasd_probe (const PedDevice *dev)

 	fdasd_check_api_version(&anchor, arch_specific->fd);

-	if (fdasd_check_volume(&anchor, arch_specific->fd))

+	/* Labels are required on CDL formatted DASDs. */

+	if (fdasd_check_volume(&anchor, arch_specific->fd) &&

+	    anchor.FBA_layout == 0)

 		goto error_cleanup;

 	fdasd_cleanup(&anchor);

@@ -273,17 +277,53 @@ dasd_read (PedDisk* disk)

 	fdasd_initialize_anchor(&anchor);

 	fdasd_get_geometry(disk->dev, &anchor, arch_specific->fd);

+	disk_specific->label_block = anchor.label_block;

+

+	if ((anchor.geo.cylinders * anchor.geo.heads) > BIG_DISK_SIZE)

+		anchor.big_disk++;

 	/* check dasd for labels and vtoc */

-	if (fdasd_check_volume(&anchor, arch_specific->fd))

-		goto error_close_dev;

+	if (fdasd_check_volume(&anchor, arch_specific->fd)) {

+		DasdPartitionData* dasd_data;

+

+		/* Kernel partitioning code will report 'implicit' partitions

+		 * for non-CDL format DASDs even when there is no

+		 * label/VTOC.  */

+		if (anchor.FBA_layout == 0)

+			goto error_close_dev;

+

+		disk_specific->format_type = 1;

+

+		/* Register implicit partition */

+		ped_disk_delete_all (disk);

+

+		start = (PedSector) arch_specific->real_sector_size /

+			(PedSector) disk->dev->sector_size *

+			(PedSector) (anchor.label_block + 1);

+		end = disk->dev->length - 1;

+		part = ped_partition_new (disk, PED_PARTITION_NORMAL, NULL,

+					  start, end);

+		if (!part)

+			goto error_close_dev;

+

+		part->num = 1;

+		part->fs_type = ped_file_system_probe (&part->geom);

+		dasd_data = part->disk_specific;

+		dasd_data->raid = 0;

+		dasd_data->lvm = 0;

+		dasd_data->type = 0;

+

+		if (!ped_disk_add_partition (disk, part, NULL))

+			goto error_close_dev;

+

+		fdasd_cleanup(&anchor);

+

+		return 1;

+	}

 	/* Save volume label (read by fdasd_check_volume) for writing */

 	memcpy(&disk_specific->vlabel, anchor.vlabel, sizeof(volume_label_t));

-	if ((anchor.geo.cylinders * anchor.geo.heads) > BIG_DISK_SIZE)

-		anchor.big_disk++;

-

 	ped_disk_delete_all (disk);

 	bool is_ldl = strncmp(anchor.vlabel->volkey,

@@ -348,7 +388,7 @@ dasd_read (PedDisk* disk)

 			    / (long long) disk->dev->sector_size

 			    * (long long) (cms_ptr->block_count - 1) - 1;

-		part = ped_partition_new (disk, PED_PARTITION_PROTECTED, NULL, start, end);

+		part = ped_partition_new (disk, PED_PARTITION_NORMAL, NULL, start, end);

 		if (!part)

 			goto error_close_dev;

@@ -923,7 +963,12 @@ dasd_alloc_metadata (PedDisk* disk)

 	   the start of the first partition */

 	if (disk_specific->format_type == 1) {

 	        part = ped_disk_get_partition(disk, 1);

-		vtoc_end = part->geom.start - 1;

+		if (part)

+			vtoc_end = part->geom.start - 1;

+		else

+			vtoc_end = (PedSector) arch_specific->real_sector_size /

+				   (PedSector) disk->dev->sector_size *

+				   (PedSector) disk_specific->label_block;

 	}

 	else {

                 if (disk->dev->type == PED_DEVICE_FILE)

@@ -943,7 +988,7 @@ dasd_alloc_metadata (PedDisk* disk)

 		goto error;

 	}

-	if (disk_specific->format_type == 1) {

+	if (disk_specific->format_type == 1 && part) {

 	   /*

 	      For LDL or CMS there may be trailing metadata as well.

 	      For example: the last block of a CMS reserved file,

--- a/libparted/labels/fdasd.c

+++ b/libparted/labels/fdasd.c

@@ -721,6 +721,7 @@ fdasd_check_volume (fdasd_anchor_t *anc,

 	unsigned long b = -1;

 	char str[LINE_LENGTH];

+	memset(v, 0, sizeof(volume_label_t));

 	vtoc_read_volume_label (fd, anc->label_pos, v);

 	if (strncmp(v->vollbl, vtoc_ebcdic_enc ("VOL1", str, 4), 4) == 0) {

@@ -800,6 +801,8 @@ fdasd_get_geometry (const PedDevice *dev

 	    dasd_info.dev_type = 13200;

 	    dasd_info.label_block = 2;

 	    dasd_info.devno = 513;

+	    dasd_info.label_block = 2;

+	    dasd_info.FBA_layout = 0;

 	} else {

 		if (ioctl(f, HDIO_GETGEO, &anc->geo) != 0)

 			fdasd_error(anc, unable_to_ioctl,

@@ -820,6 +823,8 @@ fdasd_get_geometry (const PedDevice *dev

 	anc->label_pos  = dasd_info.label_block * blksize;

 	anc->devno      = dasd_info.devno;

 	anc->fspace_trk = anc->geo.cylinders * anc->geo.heads - FIRST_USABLE_TRK;

+	anc->label_block = dasd_info.label_block;

+	anc->FBA_layout = dasd_info.FBA_layout;

 }

 /*