[PATCH] dm store geometry

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@us.ibm.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 51 insertions, 1 deletions

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 65826bdac00c..8edd6435414d 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -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 *param, size_t param_size)
         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;
@@ -1234,7 +1283,8 @@ static ioctl_fn lookup_ioctl(unsigned int cmd)
 
                 {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;