[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, 15 insertions, 2 deletions

diff --git a/include/linux/dm-ioctl.h b/include/linux/dm-ioctl.h
index fa75ba0d635e..c67c6786612a 100644
--- a/include/linux/dm-ioctl.h
+++ b/include/linux/dm-ioctl.h
@@ -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 */