Re: [dm-devel] Re: [PATCH] User-configurable HDIO_GETGEO for dm volumes
From: Alasdair G Kergon
Date: Wed Feb 22 2006 - 17:30:34 EST
On Fri, Feb 17, 2006 at 04:59:58PM -0800, Darrick J. Wong wrote:
> Here's the third revision, with the geometry pushed into mapped_device
> as well as fixes for the problems that you pointed out wrt string
> passing, lack of warning messages, etc. Thanks for all the great feedback!
Almost there now: how does the version below look?
Corresponding userspace changes are in device-mapper CVS.
Alasdair
From: "Darrick J. Wong" <djwong@xxxxxxxxxx>
Allow drive geometry to be stored with a new DM_DEV_SET_GEOMETRY ioctl.
Device-mapper will now respond to HDIO_GETGEO.
If the geometry information is not available, zero will
be returned for all of the parameters.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Signed-off-by: Alasdair G Kergon <agk@xxxxxxxxxx>
Index: linux-2.6.16-rc1/drivers/md/dm.c
===================================================================
--- linux-2.6.16-rc1.orig/drivers/md/dm.c 2006-02-22 20:44:55.000000000 +0000
+++ linux-2.6.16-rc1/drivers/md/dm.c 2006-02-22 20:44:57.000000000 +0000
@@ -17,6 +17,7 @@
#include <linux/mempool.h>
#include <linux/slab.h>
#include <linux/idr.h>
+#include <linux/hdreg.h>
static const char *_name = DM_NAME;
@@ -101,6 +102,9 @@ struct mapped_device {
*/
struct super_block *frozen_sb;
struct block_device *suspended_bdev;
+
+ /* forced geometry settings */
+ struct hd_geometry geometry;
};
#define MIN_IOS 256
@@ -226,6 +230,13 @@ static int dm_blk_close(struct inode *in
return 0;
}
+static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
+{
+ struct mapped_device *md = bdev->bd_disk->private_data;
+
+ return dm_get_geometry(md, geo);
+}
+
static inline struct dm_io *alloc_io(struct mapped_device *md)
{
return mempool_alloc(md->io_pool, GFP_NOIO);
@@ -312,6 +323,33 @@ struct dm_table *dm_get_table(struct map
return t;
}
+/*
+ * Get the geometry associated with a dm device
+ */
+int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
+{
+ *geo = md->geometry;
+
+ return 0;
+}
+
+/*
+ * Set the geometry of a device.
+ */
+int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
+{
+ sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
+
+ if (geo->start > sz) {
+ DMWARN("Start sector is beyond the geometry limits.");
+ return -EINVAL;
+ }
+
+ md->geometry = *geo;
+
+ return 0;
+}
+
/*-----------------------------------------------------------------
* CRUD START:
* A more elegant soln is in the works that uses the queue
@@ -886,6 +924,13 @@ static int __bind(struct mapped_device *
sector_t size;
size = dm_table_get_size(t);
+
+ /*
+ * Wipe any geometry if the size of the table changed.
+ */
+ if (size != get_capacity(md->disk))
+ memset(&md->geometry, 0, sizeof(md->geometry));
+
__set_size(md, size);
if (size == 0)
return 0;
@@ -1238,6 +1283,7 @@ int dm_suspended(struct mapped_device *m
static struct block_device_operations dm_blk_dops = {
.open = dm_blk_open,
.release = dm_blk_close,
+ .getgeo = dm_blk_getgeo,
.owner = THIS_MODULE
};
Index: linux-2.6.16-rc1/drivers/md/dm.h
===================================================================
--- linux-2.6.16-rc1.orig/drivers/md/dm.h 2006-02-22 20:44:56.000000000 +0000
+++ linux-2.6.16-rc1/drivers/md/dm.h 2006-02-22 20:44:57.000000000 +0000
@@ -14,6 +14,7 @@
#include <linux/device-mapper.h>
#include <linux/list.h>
#include <linux/blkdev.h>
+#include <linux/hdreg.h>
#define DM_NAME "device-mapper"
#define DMWARN(f, x...) printk(KERN_WARNING DM_NAME ": " f "\n" , ## x)
@@ -85,6 +86,12 @@ int dm_wait_event(struct mapped_device *
struct gendisk *dm_disk(struct mapped_device *md);
int dm_suspended(struct mapped_device *md);
+/*
+ * Geometry functions.
+ */
+int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo);
+int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo);
+
/*-----------------------------------------------------------------
* Functions for manipulating a table. Tables are also reference
* counted.
Index: linux-2.6.16-rc1/drivers/md/dm-ioctl.c
===================================================================
--- linux-2.6.16-rc1.orig/drivers/md/dm-ioctl.c 2006-02-22 20:44:56.000000000 +0000
+++ linux-2.6.16-rc1/drivers/md/dm-ioctl.c 2006-02-22 20:44:57.000000000 +0000
@@ -15,6 +15,7 @@
#include <linux/slab.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/dm-ioctl.h>
+#include <linux/hdreg.h>
#include <asm/uaccess.h>
@@ -700,6 +701,54 @@ static int dev_rename(struct dm_ioctl *p
return dm_hash_rename(param->name, new_name);
}
+static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
+{
+ int r = -EINVAL, x;
+ struct mapped_device *md;
+ struct hd_geometry geometry;
+ unsigned long indata[4];
+ char *geostr = (char *) param + param->data_start;
+
+ md = find_device(param);
+ if (!md)
+ return -ENXIO;
+
+ if (geostr < (char *) (param + 1) ||
+ invalid_str(geostr, (void *) param + param_size)) {
+ DMWARN("Invalid geometry supplied.");
+ goto out;
+ }
+
+ x = sscanf(geostr, "%lu %lu %lu %lu", indata,
+ indata + 1, indata + 2, indata + 3);
+
+ if (x != 4) {
+ DMWARN("Unable to interpret geometry settings.");
+ goto out;
+ }
+
+ if (indata[0] > 65535 || indata[1] > 255 ||
+ indata[2] > 255 || indata[3] > ULONG_MAX) {
+ DMWARN("Geometry exceeds range limits.");
+ goto out;
+ }
+
+ geometry.cylinders = indata[0];
+ geometry.heads = indata[1];
+ geometry.sectors = indata[2];
+ geometry.start = indata[3];
+
+ r = dm_set_geometry(md, &geometry);
+ if (!r)
+ r = __dev_status(md, param);
+
+ param->data_size = 0;
+
+out:
+ dm_put(md);
+ return r;
+}
+
static int do_suspend(struct dm_ioctl *param)
{
int r = 0;
@@ -1233,7 +1282,8 @@ static ioctl_fn lookup_ioctl(unsigned in
{DM_LIST_VERSIONS_CMD, list_versions},
- {DM_TARGET_MSG_CMD, target_message}
+ {DM_TARGET_MSG_CMD, target_message},
+ {DM_DEV_SET_GEOMETRY_CMD, dev_set_geometry}
};
return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
Index: linux-2.6.16-rc1/include/linux/compat_ioctl.h
===================================================================
--- linux-2.6.16-rc1.orig/include/linux/compat_ioctl.h 2006-02-22 20:42:48.000000000 +0000
+++ linux-2.6.16-rc1/include/linux/compat_ioctl.h 2006-02-22 20:44:57.000000000 +0000
@@ -136,6 +136,7 @@ COMPATIBLE_IOCTL(DM_TABLE_DEPS_32)
COMPATIBLE_IOCTL(DM_TABLE_STATUS_32)
COMPATIBLE_IOCTL(DM_LIST_VERSIONS_32)
COMPATIBLE_IOCTL(DM_TARGET_MSG_32)
+COMPATIBLE_IOCTL(DM_DEV_SET_GEOMETRY_32)
COMPATIBLE_IOCTL(DM_VERSION)
COMPATIBLE_IOCTL(DM_REMOVE_ALL)
COMPATIBLE_IOCTL(DM_LIST_DEVICES)
@@ -151,6 +152,7 @@ COMPATIBLE_IOCTL(DM_TABLE_DEPS)
COMPATIBLE_IOCTL(DM_TABLE_STATUS)
COMPATIBLE_IOCTL(DM_LIST_VERSIONS)
COMPATIBLE_IOCTL(DM_TARGET_MSG)
+COMPATIBLE_IOCTL(DM_DEV_SET_GEOMETRY)
/* Big K */
COMPATIBLE_IOCTL(PIO_FONT)
COMPATIBLE_IOCTL(GIO_FONT)
Index: linux-2.6.16-rc1/include/linux/dm-ioctl.h
===================================================================
--- linux-2.6.16-rc1.orig/include/linux/dm-ioctl.h 2006-02-22 20:42:48.000000000 +0000
+++ linux-2.6.16-rc1/include/linux/dm-ioctl.h 2006-02-22 20:44:57.000000000 +0000
@@ -80,6 +80,16 @@
*
* DM_TARGET_MSG:
* Pass a message string to the target at a specific offset of a device.
+ *
+ * DM_DEV_SET_GEOMETRY:
+ * Set the geometry of a device by passing in a string in this format:
+ *
+ * "cylinders heads sectors_per_track start_sector"
+ *
+ * Beware that CHS geometry is nearly obsolete and only provided
+ * for compatibility with dm devices that can be booted by a PC
+ * BIOS. See struct hd_geometry for range limits. Also note that
+ * the geometry is erased if the device size changes.
*/
/*
@@ -218,6 +228,7 @@ enum {
/* Added later */
DM_LIST_VERSIONS_CMD,
DM_TARGET_MSG_CMD,
+ DM_DEV_SET_GEOMETRY_CMD
};
/*
@@ -247,6 +258,7 @@ typedef char ioctl_struct[308];
#define DM_TABLE_STATUS_32 _IOWR(DM_IOCTL, DM_TABLE_STATUS_CMD, ioctl_struct)
#define DM_LIST_VERSIONS_32 _IOWR(DM_IOCTL, DM_LIST_VERSIONS_CMD, ioctl_struct)
#define DM_TARGET_MSG_32 _IOWR(DM_IOCTL, DM_TARGET_MSG_CMD, ioctl_struct)
+#define DM_DEV_SET_GEOMETRY_32 _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, ioctl_struct)
#endif
#define DM_IOCTL 0xfd
@@ -270,11 +282,12 @@ typedef char ioctl_struct[308];
#define DM_LIST_VERSIONS _IOWR(DM_IOCTL, DM_LIST_VERSIONS_CMD, struct dm_ioctl)
#define DM_TARGET_MSG _IOWR(DM_IOCTL, DM_TARGET_MSG_CMD, struct dm_ioctl)
+#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
#define DM_VERSION_MAJOR 4
-#define DM_VERSION_MINOR 5
+#define DM_VERSION_MINOR 6
#define DM_VERSION_PATCHLEVEL 0
-#define DM_VERSION_EXTRA "-ioctl (2005-10-04)"
+#define DM_VERSION_EXTRA "-ioctl (2006-02-17)"
/* Status bits */
#define DM_READONLY_FLAG (1 << 0) /* In/Out */
-
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