Hi,
while we understand what you want to achieve, we have two issues with
this patch:
The assumption that a CDL disk has always 12 blocks per track is not
correct. The number of blocks per track depends on the formatted
blocksize and also on the hardware.
On the one side you add two parameters to distinguish between CDL and
LDL but you do not allow to distinguish between ECKD and FBA. The
difference between CDL and LDL could be deduced from the volume label
itself but the ECKD/FBA distinction is important because the label block
position depends on this (info->label_block).
The case of FBA devices seems important to us because people may want to
use images they can copy from or to z/VM emulated FBA devices on SCSI
disks (EDEV).
Am 31.03.2011 17:59, schrieb Alexander Graf:
Currently we can only use the DASD partition label on DASD disks. When running
a VM in KVM, we only have virtio disks available though. In order to still be
able to use DASD formatted disks, we need a flag that allows us to force enable
detection of the DASD partition label. This patch implements parameters to
achieve this.
For example, to activate the label code to force devices "vda" and "vdb" to be
detected as CDL style label, add "ibm.dasd_force_cdl=vda,vdb" to your kernel
command line. A respective parameter is also added for the LDL label type.
Signed-off-by: Alexander Graf<agraf@xxxxxxx>
---
fs/partitions/ibm.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 48 insertions(+), 2 deletions(-)
diff --git a/fs/partitions/ibm.c b/fs/partitions/ibm.c
index d513a07..5a4b9f6 100644
--- a/fs/partitions/ibm.c
+++ b/fs/partitions/ibm.c
@@ -17,6 +17,30 @@
#include "check.h"
#include "ibm.h"
+static char *dasd_force_ldl[4];
+static char *dasd_force_cdl[4];
+
+module_param_array(dasd_force_ldl, charp, NULL, 0);
+MODULE_PARM_DESC(dasd_force_ldl, "force a block device to be detected as DASD "
+ "(LDL format)");
+module_param_array(dasd_force_cdl, charp, NULL, 0);
+MODULE_PARM_DESC(dasd_force_cdl, "force a block device to be detected as DASD "
+ "(CDL format)");
+
+static inline bool match_array(char **arr, const char *match)
+{
+ if (!arr)
+ return false;
+
+ while (*arr) {
+ if (!strcmp(*arr, match))
+ return true;
+ arr++;
+ }
+
+ return false;
+}
+
/*
* compute the block number from a
* cyl-cyl-head-head structure
@@ -76,6 +100,7 @@ int ibm_partition(struct parsed_partitions *state)
Sector sect;
sector_t labelsect;
char tmp[64];
+ bool fake_cdl = false;
res = 0;
blocksize = bdev_logical_block_size(bdev);
@@ -95,10 +120,31 @@ int ibm_partition(struct parsed_partitions *state)
if (label == NULL)
goto out_nolab;
- if (ioctl_by_bdev(bdev, BIODASDINFO2, (unsigned long)info) != 0 ||
- ioctl_by_bdev(bdev, HDIO_GETGEO, (unsigned long)geo) != 0)
+ if (match_array(dasd_force_ldl, bdev->bd_disk->disk_name)) {
+ memset(info, 0, sizeof(dasd_information2_t));
+ info->format = DASD_FORMAT_LDL;
+ info->label_block = 2;
+ } else if (match_array(dasd_force_cdl, bdev->bd_disk->disk_name)) {
+ memset(info, 0, sizeof(dasd_information2_t));
+ info->format = DASD_FORMAT_CDL;
+ info->label_block = 2;
+ fake_cdl = true;
+ } else if (ioctl_by_bdev(bdev, BIODASDINFO2, (unsigned long)info) != 0) {
+ goto out_freeall;
+ }
+
+ if (ioctl_by_bdev(bdev, HDIO_GETGEO, (unsigned long)geo) != 0)
goto out_freeall;
+ if (fake_cdl) {
+ memset(geo, 0, sizeof(dasd_information2_t));
geo is from type struct hd_geometry
+ /* CDL disks always are on 15/12 layout, so calculate over */
+ geo->cylinders = (geo->heads * geo->sectors * geo->cylinders)
+ / (15 * 12);
geo->cylinders is alway 0 if you calculate with values from geo set to 0
+ geo->heads = 15;
+ geo->sectors = 12;
+ }
+
/*
* Special case for FBA disks: label sector does not depend on
* blocksize.
regards
Stefan
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