Reads the disk geometry to be able to align disk partitions on cylinder boundries. Msdos partition tables really like this stuff.

--- libvirt-0.6.4.org/src/parthelper.c 2009-06-23 13:07:38.167048000 +0200 +++ libvirt-0.6.4/src/parthelper.c 2009-06-23 17:13:27.636892000 +0200 @@ -41,14 +41,22 @@ # define PED_PARTITION_PROTECTED 0 #endif +enum diskCommand { + DISK_LAYOUT = 0, + DISK_GEOMETRY +}; + int main(int argc, char **argv) { PedDevice *dev; PedDisk *disk; PedPartition *part; + int cmd = DISK_LAYOUT; - if (argc != 2) { - fprintf(stderr, "syntax: %s DEVICE\n", argv[0]); + if (argc == 3 && !strcmp(argv[2], "-g")) { + cmd = DISK_GEOMETRY; + } else if (argc != 2) { + fprintf(stderr, "syntax: %s DEVICE [-g]\n", argv[0]); return 1; } @@ -57,6 +65,15 @@ int main(int argc, char **argv) return 2; } + /* return the geometry of the disk and then exit */ + if(cmd == DISK_GEOMETRY) { + printf("%d%c%d%c%d%c%", + dev->hw_geom.cylinders, '\0', + dev->hw_geom.heads, '\0', + dev->hw_geom.sectors, '\0'); + return 0; + } + if ((disk = ped_disk_new(dev)) == NULL) { fprintf(stderr, "unable to access disk %s\n", argv[1]); return 2; --- libvirt-0.6.4.org/src/storage_conf.h 2009-06-23 16:46:47.946019000 +0200 +++ libvirt-0.6.4/src/storage_conf.h 2009-06-23 17:38:23.705006000 +0200 @@ -188,6 +188,13 @@ struct _virStoragePoolSourceDevice { virStoragePoolSourceDeviceExtentPtr freeExtents; char *path; int format; /* Pool specific source format */ + /* When the source device is a physical disk, + the geometry data is needed */ + struct _geometry { + int cyliders; + int heads; + int sectors; + } geometry; }; --- libvirt-0.6.4.org/src/storage_backend_disk.c 2009-06-23 16:46:47.957024000 +0200 +++ libvirt-0.6.4/src/storage_backend_disk.c 2009-06-23 17:47:35.118203000 +0200 @@ -303,6 +303,35 @@ virStorageBackendDiskReadPartitions(virC vol); } +static int +virStorageBackendDiskMakePoolGeometry(virConnectPtr conn ATTRIBUTE_UNUSED, + virStoragePoolObjPtr pool, + size_t ntok ATTRIBUTE_UNUSED, + char **const groups, + void *data ATTRIBUTE_UNUSED) +{ + + pool->def->source.devices[0].geometry.cyliders = atoi(groups[0]); + pool->def->source.devices[0].geometry.heads = atoi(groups[1]); + pool->def->source.devices[0].geometry.sectors = atoi(groups[2]); + + return 0; +} + +static int +virStorageBackendDiskReadGeometry(virConnectPtr conn, virStoragePoolObjPtr pool) +{ + const char *prog[] = { + PARTHELPER, pool->def->source.devices[0].path, "-g", NULL, + }; + + return virStorageBackendRunProgNul(conn, + pool, + prog, + 3, + virStorageBackendDiskMakePoolGeometry, + NULL); +} static int virStorageBackendDiskRefreshPool(virConnectPtr conn, @@ -313,6 +342,10 @@ virStorageBackendDiskRefreshPool(virConn virStorageBackendWaitForDevices(conn); + if (virStorageBackendDiskReadGeometry(conn, pool) != 0) { + return -1; + } + return virStorageBackendDiskReadPartitions(conn, pool, NULL); }