blktap2: Fix tapdisk disktype issues.

Stop coercing drivers/disktype code into the tool stack. Make both
blktapctrl and tap-ctl transfer type/path pairs as "<type>:<path>"
strings. Remove the message.disktype integer altogether.

Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>
Signed-off-by: Jake Wires <jake.wires@citrix.com>

22 files changed, 311 insertions, 283 deletions

diff --git a/tools/blktap2/drivers/Makefile b/tools/blktap2/drivers/Makefile
index 56ddfd94d3..88d3a8c8b5 100644
--- a/tools/blktap2/drivers/Makefile
+++ b/tools/blktap2/drivers/Makefile
@@ -65,6 +65,7 @@ TAP-OBJS-y  := scheduler.o
 TAP-OBJS-y  += tapdisk-vbd.o
 TAP-OBJS-y  += tapdisk-image.o
 TAP-OBJS-y  += tapdisk-driver.o
+TAP-OBJS-y  += tapdisk-disktype.o
 TAP-OBJS-y  += tapdisk-interface.o
 TAP-OBJS-y  += tapdisk-server.o
 TAP-OBJS-y  += tapdisk-queue.o
diff --git a/tools/blktap2/drivers/block-qcow.c b/tools/blktap2/drivers/block-qcow.c
index 3e15d15682..ac55ac9387 100644
--- a/tools/blktap2/drivers/block-qcow.c
+++ b/tools/blktap2/drivers/block-qcow.c
@@ -41,6 +41,7 @@
 #include "tapdisk.h"
 #include "tapdisk-driver.h"
 #include "tapdisk-interface.h"
+#include "tapdisk-disktype.h"
 #include "qcow.h"
 #include "blk.h"
 #include "atomicio.h"
diff --git a/tools/blktap2/drivers/block-remus.c b/tools/blktap2/drivers/block-remus.c
index f6da984e27..0af8189ae7 100644
--- a/tools/blktap2/drivers/block-remus.c
+++ b/tools/blktap2/drivers/block-remus.c
@@ -98,6 +98,7 @@ struct req_ring {
  */
 td_vbd_t *device_vbd = NULL;
 td_image_t *remus_image = NULL;
+struct tap_disk tapdisk_remus;
 
 struct ramdisk {
 	size_t sector_size;
diff --git a/tools/blktap2/drivers/block-vhd.c b/tools/blktap2/drivers/block-vhd.c
index 83db6e38ba..649664a8a5 100644
--- a/tools/blktap2/drivers/block-vhd.c
+++ b/tools/blktap2/drivers/block-vhd.c
@@ -58,6 +58,7 @@
 #include "tapdisk.h"
 #include "tapdisk-driver.h"
 #include "tapdisk-interface.h"
+#include "tapdisk-disktype.h"
 
 unsigned int SPB;
 
diff --git a/tools/blktap2/drivers/disktypes.h b/tools/blktap2/drivers/disktypes.h
deleted file mode 100644
index 74a98d2c34..0000000000
--- a/tools/blktap2/drivers/disktypes.h
+++ /dev/null
@@ -1,197 +0,0 @@
-/* 
- * Copyright (c) 2007, XenSource Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *     * Redistributions of source code must retain the above copyright
- *       notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above copyright
- *       notice, this list of conditions and the following disclaimer in the
- *       documentation and/or other materials provided with the distribution.
- *     * Neither the name of XenSource Inc. nor the names of its contributors
- *       may be used to endorse or promote products derived from this software
- *       without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
- * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
- * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
- * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#ifndef __DISKTYPES_H__
-#define __DISKTYPES_H__
-
-typedef struct disk_info {
-       int  idnum;
-       char name[50];       /* e.g. "RAMDISK" */
-       char handle[10];     /* xend handle, e.g. 'ram' */
-       int  single_handler; /* is there a single controller for all */
-                            /* instances of disk type? */
-#ifdef TAPDISK
-       struct tap_disk *drv;
-#endif
-} disk_info_t;
-
-extern struct tap_disk tapdisk_aio;
-/* extern struct tap_disk tapdisk_sync;    */
-/* extern struct tap_disk tapdisk_vmdk;    */
-/* extern struct tap_disk tapdisk_vhdsync; */
-extern struct tap_disk tapdisk_vhd;
-extern struct tap_disk tapdisk_ram;
- extern struct tap_disk tapdisk_qcow; 
-extern struct tap_disk tapdisk_block_cache;
-extern struct tap_disk tapdisk_log;
-extern struct tap_disk tapdisk_remus;
-
-#define MAX_DISK_TYPES        20
-
-#define DISK_TYPE_AIO         0
-#define DISK_TYPE_SYNC        1
-#define DISK_TYPE_VMDK        2
-#define DISK_TYPE_VHDSYNC     3
-#define DISK_TYPE_VHD         4
-#define DISK_TYPE_RAM         5
-#define DISK_TYPE_QCOW        6
-#define DISK_TYPE_BLOCK_CACHE 7
-#define DISK_TYPE_LOG         9
-#define DISK_TYPE_REMUS       10
-
-/*Define Individual Disk Parameters here */
-static disk_info_t null_disk = {
-       -1,
-       "null disk",
-       "null",
-       0,
-#ifdef TAPDISK
-       0,
-#endif
-};
-
-static disk_info_t aio_disk = {
-       DISK_TYPE_AIO,
-       "raw image (aio)",
-       "aio",
-       0,
-#ifdef TAPDISK
-       &tapdisk_aio,
-#endif
-};
-/*
-static disk_info_t sync_disk = {
-       DISK_TYPE_SYNC,
-       "raw image (sync)",
-       "sync",
-       0,
-#ifdef TAPDISK
-       &tapdisk_sync,
-#endif
-};
-
-static disk_info_t vmdk_disk = {
-       DISK_TYPE_VMDK,
-       "vmware image (vmdk)",
-       "vmdk",
-       1,
-#ifdef TAPDISK
-       &tapdisk_vmdk,
-#endif
-};
-
-static disk_info_t vhdsync_disk = {
-       DISK_TYPE_VHDSYNC,
-       "virtual server image (vhd) - synchronous",
-       "vhdsync",
-       1,
-#ifdef TAPDISK
-       &tapdisk_vhdsync,
-#endif
-};
-*/
-
-static disk_info_t vhd_disk = {
-       DISK_TYPE_VHD,
-       "virtual server image (vhd)",
-       "vhd",
-       0,
-#ifdef TAPDISK
-       &tapdisk_vhd,
-#endif
-};
-
-
-static disk_info_t ram_disk = {
-       DISK_TYPE_RAM,
-       "ramdisk image (ram)",
-       "ram",
-       1,
-#ifdef TAPDISK
-       &tapdisk_ram,
-#endif
-};
-
-
-static disk_info_t qcow_disk = {
-       DISK_TYPE_QCOW,
-       "qcow disk (qcow)",
-       "qcow",
-       0,
-#ifdef TAPDISK
-       &tapdisk_qcow,
-#endif
-};
-
-
-static disk_info_t block_cache_disk = {
-       DISK_TYPE_BLOCK_CACHE,
-       "block cache image (bc)",
-       "bc",
-       1,
-#ifdef TAPDISK
-       &tapdisk_block_cache,
-#endif
-};
-
-static disk_info_t log_disk = {
-	DISK_TYPE_LOG,
-	"write logger (log)",
-	"log",
-	0,
-#ifdef TAPDISK
-	&tapdisk_log,
-#endif
-};
-
-static disk_info_t remus_disk = {
-       DISK_TYPE_REMUS,
-       "remus disk replicator (remus)",
-       "remus",
-       0,
-#ifdef TAPDISK
-       &tapdisk_remus,
-#endif
-};
-
-/*Main disk info array */
-static disk_info_t *dtypes[] = {
-       &aio_disk,
-       &null_disk, /* &sync_disk, */
-       &null_disk, /* &vmdk_disk, */
-        &null_disk, /* &vhdsync_disk, */
-       &vhd_disk,
-       &ram_disk,
-       &qcow_disk,
-       &block_cache_disk,
-       &null_disk,
-       &log_disk,
-       &remus_disk,
-};
-
-#endif
diff --git a/tools/blktap2/drivers/img2qcow.c b/tools/blktap2/drivers/img2qcow.c
index 08f3335dbb..17a89296f9 100644
--- a/tools/blktap2/drivers/img2qcow.c
+++ b/tools/blktap2/drivers/img2qcow.c
@@ -48,6 +48,7 @@
 #include "tapdisk-server.h"
 #include "tapdisk-driver.h"
 #include "tapdisk-interface.h"
+#include "tapdisk-disktype.h"
 #include "qcow.h"
 #include "blk.h"
 
diff --git a/tools/blktap2/drivers/qcow2raw.c b/tools/blktap2/drivers/qcow2raw.c
index e581b1e40e..04cb26eae4 100644
--- a/tools/blktap2/drivers/qcow2raw.c
+++ b/tools/blktap2/drivers/qcow2raw.c
@@ -47,6 +47,7 @@
 #include "tapdisk-server.h"
 #include "tapdisk-driver.h"
 #include "tapdisk-interface.h"
+#include "tapdisk-disktype.h"
 #include "qcow.h"
 
 #if 1
diff --git a/tools/blktap2/drivers/tapdisk-diff.c b/tools/blktap2/drivers/tapdisk-diff.c
index 2c4994888d..1d2ba8e682 100644
--- a/tools/blktap2/drivers/tapdisk-diff.c
+++ b/tools/blktap2/drivers/tapdisk-diff.c
@@ -38,6 +38,7 @@
 #include "scheduler.h"
 #include "tapdisk-vbd.h"
 #include "tapdisk-server.h"
+#include "tapdisk-disktype.h"
 #include "libvhd.h"
 
 #define POLL_READ                        0
@@ -670,11 +671,11 @@ static int
 tapdisk_stream_open(struct tapdisk_stream *s, const char *arg)
 {
 	int err, type;
-	char *path;
+	const char *path;
 
-	err = tapdisk_parse_disk_type(arg, &path, &type);
-	if (err)
-		return err;
+	type = tapdisk_disktype_parse_params(arg, &path);
+	if (type < 0)
+		return type;
 
 	tapdisk_stream_initialize(s);
 
@@ -716,7 +717,8 @@ main(int argc, char *argv[])
 {
 	int c, err, type1;
 	const char *arg1 = NULL, *arg2 = NULL;
-	char *path1;
+	const disk_info_t *info;
+	const char *path1;
 
 	err    = 0;
 
@@ -741,9 +743,10 @@ main(int argc, char *argv[])
 	if (!arg1 || !arg2)
 		goto fail_usage;
 
-	err = tapdisk_parse_disk_type(arg1, &path1, &type1);
-	if (err)
-		return err;
+	type1 = tapdisk_disktype_parse_params(arg1, &path1);
+	if (type1 < 0)
+		return type1;
+
 	if (type1 != DISK_TYPE_VHD) {
 		printf("error: first VDI is not VHD\n");
 		return EINVAL;
diff --git a/tools/blktap2/drivers/tapdisk-disktype.c b/tools/blktap2/drivers/tapdisk-disktype.c
new file mode 100644
index 0000000000..98379a6d8b
--- /dev/null
+++ b/tools/blktap2/drivers/tapdisk-disktype.c
@@ -0,0 +1,204 @@
+/*
+ * Copyright (c) 2007, 2010, XenSource Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of XenSource Inc. nor the names of its contributors
+ *       may be used to endorse or promote products derived from this software
+ *       without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+ * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stddef.h>
+#include <string.h>
+#include <errno.h>
+
+#include "tapdisk-disktype.h"
+#include "tapdisk-message.h"
+
+static const disk_info_t aio_disk = {
+       "aio",
+       "raw image (aio)",
+       0,
+};
+
+static const disk_info_t sync_disk = {
+       "sync",
+       "raw image (sync)",
+       0,
+};
+
+static const disk_info_t vmdk_disk = {
+       "vmdk",
+       "vmware image (vmdk)",
+       1,
+};
+
+static const disk_info_t vhdsync_disk = {
+       "vhdsync",
+       "virtual server image (vhd) - synchronous",
+       1,
+};
+
+static const disk_info_t vhd_disk = {
+       "vhd",
+       "virtual server image (vhd)",
+       0,
+};
+
+
+static const disk_info_t ram_disk = {
+       "ram",
+       "ramdisk image (ram)",
+       1,
+};
+
+static const disk_info_t qcow_disk = {
+       "qcow",
+       "qcow disk (qcow)",
+       0,
+};
+
+static const disk_info_t block_cache_disk = {
+       "bc",
+       "block cache image (bc)",
+       1,
+};
+
+static const disk_info_t vhd_index_disk = {
+       "vhdi",
+       "vhd index image (vhdi)",
+       1,
+};
+
+static const disk_info_t log_disk = {
+	"log",
+	"write logger (log)",
+	0,
+};
+
+static disk_info_t remus_disk = {
+       "remus disk replicator (remus)",
+       "remus",
+       0,
+};
+
+const disk_info_t *tapdisk_disk_types[] = {
+	[DISK_TYPE_AIO]	= &aio_disk,
+	[DISK_TYPE_SYNC]	= &sync_disk,
+	[DISK_TYPE_VMDK]	= &vmdk_disk,
+	[DISK_TYPE_VHDSYNC]	= &vhdsync_disk,
+	[DISK_TYPE_VHD]	= &vhd_disk,
+	[DISK_TYPE_RAM]	= &ram_disk,
+	[DISK_TYPE_QCOW]	= &qcow_disk,
+	[DISK_TYPE_BLOCK_CACHE] = &block_cache_disk,
+	[DISK_TYPE_LOG]	= &log_disk,
+	[DISK_TYPE_VINDEX]	= &vhd_index_disk,
+	[DISK_TYPE_REMUS]	= &remus_disk,
+	0,
+};
+
+extern struct tap_disk tapdisk_aio;
+extern struct tap_disk tapdisk_sync;
+extern struct tap_disk tapdisk_vmdk;
+extern struct tap_disk tapdisk_vhdsync;
+extern struct tap_disk tapdisk_vhd;
+extern struct tap_disk tapdisk_ram;
+extern struct tap_disk tapdisk_qcow;
+extern struct tap_disk tapdisk_block_cache;
+extern struct tap_disk tapdisk_vhd_index;
+extern struct tap_disk tapdisk_log;
+extern struct tap_disk tapdisk_remus;
+
+const struct tap_disk *tapdisk_disk_drivers[] = {
+	[DISK_TYPE_AIO]         = &tapdisk_aio,
+#if 0
+	[DISK_TYPE_SYNC]        = &tapdisk_sync,
+	[DISK_TYPE_VMDK]        = &tapdisk_vmdk,
+#endif
+	[DISK_TYPE_VHD]         = &tapdisk_vhd,
+	[DISK_TYPE_RAM]         = &tapdisk_ram,
+	[DISK_TYPE_QCOW]        = &tapdisk_qcow,
+	[DISK_TYPE_BLOCK_CACHE] = &tapdisk_block_cache,
+	[DISK_TYPE_VINDEX]      = &tapdisk_vhd_index,
+	[DISK_TYPE_LOG]         = &tapdisk_log,
+	[DISK_TYPE_REMUS]       = &tapdisk_remus,
+	0,
+};
+
+int
+tapdisk_disktype_find(const char *name)
+{
+	const disk_info_t *info;
+	int i;
+
+	for (i = 0; info = tapdisk_disk_types[i], info != NULL; ++i) {
+		if (strcmp(name, info->name))
+			continue;
+
+		if (!tapdisk_disk_drivers[i])
+			return -ENOSYS;
+
+		return i;
+	}
+
+	return -ENOENT;
+}
+
+int
+tapdisk_disktype_parse_params(const char *params, const char **_path)
+{
+	char name[DISK_TYPE_NAME_MAX], *ptr;
+	size_t len;
+	int type;
+
+	ptr = strchr(params, ':');
+	if (!ptr)
+		return -EINVAL;
+
+	len = ptr - params;
+
+	if (len > sizeof(name) - 1)
+		return -ENAMETOOLONG;
+
+	memset(name, 0, sizeof(name));
+	strncpy(name, params, len);
+
+	type = tapdisk_disktype_find(name);
+
+	if (type >= 0)
+		*_path = params + len + 1;
+
+	return type;
+}
+
+int
+tapdisk_parse_disk_type(const char *params, const char **_path, int *_type)
+{
+	int type;
+
+	type = tapdisk_disktype_parse_params(params, _path);
+	if (type < 0)
+		return type;
+
+	*_type = type;
+
+	return 0;
+}
diff --git a/tools/blktap2/drivers/tapdisk-disktype.h b/tools/blktap2/drivers/tapdisk-disktype.h
new file mode 100644
index 0000000000..61adc21e55
--- /dev/null
+++ b/tools/blktap2/drivers/tapdisk-disktype.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2007, 2010, XenSource Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of XenSource Inc. nor the names of its contributors
+ *       may be used to endorse or promote products derived from this software
+ *       without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+ * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __DISKTYPES_H__
+#define __DISKTYPES_H__
+
+#define DISK_TYPE_AIO         0
+#define DISK_TYPE_SYNC        1
+#define DISK_TYPE_VMDK        2
+#define DISK_TYPE_VHDSYNC     3
+#define DISK_TYPE_VHD         4
+#define DISK_TYPE_RAM         5
+#define DISK_TYPE_QCOW        6
+#define DISK_TYPE_BLOCK_CACHE 7
+#define DISK_TYPE_LOG         9
+#define DISK_TYPE_REMUS       10
+#define DISK_TYPE_VINDEX      11
+
+#define DISK_TYPE_NAME_MAX    32
+
+typedef struct disk_info {
+	const char     *name; /* driver name, e.g. 'aio' */
+	char           *desc;  /* e.g. "raw image" */
+	unsigned int    flags; 
+} disk_info_t;
+
+extern const disk_info_t     *tapdisk_disk_types[];
+extern const struct tap_disk *tapdisk_disk_drivers[];
+
+/* one single controller for all instances of disk type */
+#define DISK_TYPE_SINGLE_CONTROLLER (1<<0)
+
+int tapdisk_disktype_find(const char *name);
+int tapdisk_disktype_parse_params(const char *params, const char **_path);
+int tapdisk_parse_disk_type(const char *, const char **, int *);
+
+#endif
diff --git a/tools/blktap2/drivers/tapdisk-driver.c b/tools/blktap2/drivers/tapdisk-driver.c
index ca5629ab73..aa1ed15f40 100644
--- a/tools/blktap2/drivers/tapdisk-driver.c
+++ b/tools/blktap2/drivers/tapdisk-driver.c
@@ -29,15 +29,16 @@
 
 #include "tapdisk-driver.h"
 #include "tapdisk-server.h"
+#include "tapdisk-disktype.h"
 
 td_driver_t *
 tapdisk_driver_allocate(int type, char *name, td_flag_t flags, int storage)
 {
 	int err;
 	td_driver_t *driver;
-	struct tap_disk *ops;
+	const struct tap_disk *ops;
 
-	ops = tapdisk_server_find_driver_interface(type);
+	ops = tapdisk_disk_drivers[type];
 	if (!ops)
 		return NULL;
 
diff --git a/tools/blktap2/drivers/tapdisk-driver.h b/tools/blktap2/drivers/tapdisk-driver.h
index de0a9be233..42de05db1d 100644
--- a/tools/blktap2/drivers/tapdisk-driver.h
+++ b/tools/blktap2/drivers/tapdisk-driver.h
@@ -47,7 +47,7 @@ struct td_driver_handle {
 	td_disk_info_t               info;
 
 	void                        *data;
-	struct tap_disk             *ops;
+	const struct tap_disk       *ops;
 
 	struct list_head             next;
 };
diff --git a/tools/blktap2/drivers/tapdisk-image.c b/tools/blktap2/drivers/tapdisk-image.c
index 2193ceddc6..042cdd5ad2 100644
--- a/tools/blktap2/drivers/tapdisk-image.c
+++ b/tools/blktap2/drivers/tapdisk-image.c
@@ -39,7 +39,7 @@
 #define ERR(_err, _f, _a...) tlog_error(_err, _f, ##_a)
 
 td_image_t *
-tapdisk_image_allocate(char *file, int type, int storage,
+tapdisk_image_allocate(const char *file, int type, int storage,
 		       td_flag_t flags, void *private)
 {
 	int err;
diff --git a/tools/blktap2/drivers/tapdisk-image.h b/tools/blktap2/drivers/tapdisk-image.h
index 33b1b851c3..60375aeab2 100644
--- a/tools/blktap2/drivers/tapdisk-image.h
+++ b/tools/blktap2/drivers/tapdisk-image.h
@@ -47,7 +47,7 @@ struct td_image_handle {
 	struct list_head             next;
 };
 
-td_image_t *tapdisk_image_allocate(char *, int, int, td_flag_t, void *);
+td_image_t *tapdisk_image_allocate(const char *, int, int, td_flag_t, void *);
 void tapdisk_image_free(td_image_t *);
 
 int tapdisk_image_check_td_request(td_image_t *, td_request_t);
diff --git a/tools/blktap2/drivers/tapdisk-server.c b/tools/blktap2/drivers/tapdisk-server.c
index 869fa239a1..73e9717815 100644
--- a/tools/blktap2/drivers/tapdisk-server.c
+++ b/tools/blktap2/drivers/tapdisk-server.c
@@ -32,7 +32,6 @@
 #include <sys/ioctl.h>
 #include <sys/signal.h>
 
-#define TAPDISK
 #include "tapdisk-utils.h"
 #include "tapdisk-server.h"
 #include "tapdisk-driver.h"
@@ -46,18 +45,6 @@
 #define tapdisk_server_for_each_vbd(vbd, tmp)			        \
 	list_for_each_entry_safe(vbd, tmp, &server.vbds, next)
 
-struct tap_disk *
-tapdisk_server_find_driver_interface(int type)
-{
-	int n;
-
-	n = sizeof(dtypes) / sizeof(struct disk_info_t *);
-	if (type >= n)
-		return NULL;
-
-	return dtypes[type]->drv;
-}
-
 td_image_t *
 tapdisk_server_get_shared_image(td_image_t *image)
 {
diff --git a/tools/blktap2/drivers/tapdisk-stream.c b/tools/blktap2/drivers/tapdisk-stream.c
index 4e0f9a8f12..1795abddfd 100644
--- a/tools/blktap2/drivers/tapdisk-stream.c
+++ b/tools/blktap2/drivers/tapdisk-stream.c
@@ -37,6 +37,7 @@
 #include "scheduler.h"
 #include "tapdisk-vbd.h"
 #include "tapdisk-server.h"
+#include "tapdisk-disktype.h"
 
 #define POLL_READ                        0
 #define POLL_WRITE                       1
@@ -545,7 +546,9 @@ int
 main(int argc, char *argv[])
 {
 	int c, err, type;
-	char *params, *path;
+	const char *params;
+	const disk_info_t *info;
+	const char *path;
 	uint64_t count, skip;
 	struct tapdisk_stream stream;
 
@@ -575,8 +578,9 @@ main(int argc, char *argv[])
 	if (!params)
 		usage(argv[0], EINVAL);
 
-	err = tapdisk_parse_disk_type(params, &path, &type);
-	if (err) {
+	type = tapdisk_disktype_parse_params(params, &path);
+	if (type < 0) {
+		err = type;
 		fprintf(stderr, "invalid argument %s: %d\n", params, err);
 		return err;
 	}
diff --git a/tools/blktap2/drivers/tapdisk-utils.c b/tools/blktap2/drivers/tapdisk-utils.c
index 757c0bdc77..1b15f12154 100644
--- a/tools/blktap2/drivers/tapdisk-utils.c
+++ b/tools/blktap2/drivers/tapdisk-utils.c
@@ -40,7 +40,6 @@
 
 #include "blk.h"
 #include "tapdisk.h"
-#include "disktypes.h"
 #include "blktaplib.h"
 #include "tapdisk-log.h"
 #include "tapdisk-utils.h"
@@ -108,45 +107,6 @@ tapdisk_namedup(char **dup, const char *name)
 	return 0;
 }
 
-int
-tapdisk_parse_disk_type(const char *params, char **_path, int *_type)
-{
-        int i, err, size, handle_len;
-	char *ptr, *path, handle[10];
-
-	if (strlen(params) + 1 >= MAX_NAME_LEN)
-		return -ENAMETOOLONG;
-
-	ptr = strchr(params, ':');
-	if (!ptr)
-		return -EINVAL;
-
-	path = ptr + 1;
-
-        handle_len = ptr - params;
-        if (handle_len > sizeof(handle))
-          return -ENAMETOOLONG;
-        
-        memcpy(handle, params, handle_len);
-        handle[handle_len] = '\0';
-               
-	size = sizeof(dtypes) / sizeof(disk_info_t *);
-	for (i = 0; i < size; i++) {
-          if (strncmp(handle, dtypes[i]->handle, handle_len))
-			continue;
-
-		if (dtypes[i]->idnum == -1)
-			return -ENODEV;
-
-		*_type = dtypes[i]->idnum;
-		*_path = path;
-
-		return 0;
-	}
-
-	return -ENODEV;
-}
-
 /*Get Image size, secsize*/
 int
 tapdisk_get_image_size(int fd, uint64_t *_sectors, uint32_t *_sector_size)
diff --git a/tools/blktap2/drivers/tapdisk-utils.h b/tools/blktap2/drivers/tapdisk-utils.h
index 5e08aa8326..7b7c3d5e92 100644
--- a/tools/blktap2/drivers/tapdisk-utils.h
+++ b/tools/blktap2/drivers/tapdisk-utils.h
@@ -36,7 +36,6 @@ void tapdisk_start_logging(const char *);
 void tapdisk_stop_logging(void);
 int tapdisk_set_resource_limits(void);
 int tapdisk_namedup(char **, const char *);
-int tapdisk_parse_disk_type(const char *, char **, int *);
 int tapdisk_get_image_size(int, uint64_t *, uint32_t *);
 int tapdisk_linux_version(void);
 
diff --git a/tools/blktap2/drivers/tapdisk-vbd.c b/tools/blktap2/drivers/tapdisk-vbd.c
index fee1bad68f..65300acbf9 100644
--- a/tools/blktap2/drivers/tapdisk-vbd.c
+++ b/tools/blktap2/drivers/tapdisk-vbd.c
@@ -43,6 +43,7 @@
 #include "tapdisk-driver.h"
 #include "tapdisk-server.h"
 #include "tapdisk-interface.h"
+#include "tapdisk-disktype.h"
 #include "tapdisk-vbd.h"
 #include "blktap2.h"
 
@@ -282,9 +283,9 @@ fail:
 
 /* TODO: ugh, lets not call it parent info... */
 static struct list_head *
-tapdisk_vbd_open_level(td_vbd_t *vbd, char* params, int driver_type, td_disk_info_t *parent_info, td_flag_t flags)
+tapdisk_vbd_open_level(td_vbd_t *vbd, const char* params, int driver_type, td_disk_info_t *parent_info, td_flag_t flags)
 {
-	char *name;
+	const char *name;
 	int type, err;
 	td_image_t *image;
 	td_disk_id_t id;
@@ -294,19 +295,16 @@ tapdisk_vbd_open_level(td_vbd_t *vbd, char* params, int driver_type, td_disk_inf
 	images = calloc(1, sizeof(struct list_head));
 	INIT_LIST_HEAD(images);
 
-	name   = params;
-	type   = driver_type;
+	name    = params;
+	id.name = NULL;
+	type    = driver_type;
 
 	for (;;) {
 		err   = -ENOMEM;
 		image = tapdisk_image_allocate(name, type,
 					       vbd->storage, flags, vbd);
 
-		/* free 'name' if it was created by td_get_parent_id() */
-		if (name != params) {
-			free(name);
-			name = NULL;
-		}
+		free(id.name);
 
 		if (!image)
 			return NULL;
@@ -382,7 +380,7 @@ tapdisk_vbd_open_level(td_vbd_t *vbd, char* params, int driver_type, td_disk_inf
 static int
 __tapdisk_vbd_open_vdi(td_vbd_t *vbd, td_flag_t extra_flags)
 {
-	char *file;
+	const char *file;
 	int err, type;
 	td_flag_t flags;
 	td_disk_id_t id;
@@ -524,9 +522,9 @@ tapdisk_vbd_open_vdi(td_vbd_t *vbd, const char *path,
 		     uint16_t drivertype, uint16_t storage, td_flag_t flags)
 {
 	int i, err;
-	struct tap_disk *ops;
+	const struct tap_disk *ops;
 
-	ops = tapdisk_server_find_driver_interface(drivertype);
+	ops = tapdisk_disk_drivers[drivertype];
 	if (!ops)
 		return -EINVAL;
 	DPRINTF("Loaded %s driver for vbd %u %s 0x%08x\n",
@@ -1573,7 +1571,8 @@ static int
 tapdisk_vbd_resume_ring(td_vbd_t *vbd)
 {
 	int i, err, type;
-	char *path, message[BLKTAP2_MAX_MESSAGE_LEN];
+	char message[BLKTAP2_MAX_MESSAGE_LEN];
+	const char *path;
 
 	memset(message, 0, sizeof(message));
 
diff --git a/tools/blktap2/drivers/tapdisk-vbd.h b/tools/blktap2/drivers/tapdisk-vbd.h
index 033a6b796d..3d26942582 100644
--- a/tools/blktap2/drivers/tapdisk-vbd.h
+++ b/tools/blktap2/drivers/tapdisk-vbd.h
@@ -80,7 +80,7 @@ struct td_vbd_request {
 };
 
 struct td_vbd_driver_info {
-	char                       *params;
+	const char                 *params;
 	int                         type;
 	struct list_head            next;
 };
diff --git a/tools/blktap2/drivers/tapdisk.h b/tools/blktap2/drivers/tapdisk.h
index 460bc88d97..6625de0001 100644
--- a/tools/blktap2/drivers/tapdisk.h
+++ b/tools/blktap2/drivers/tapdisk.h
@@ -61,7 +61,6 @@
 
 #include "list.h"
 #include "blktaplib.h"
-#include "disktypes.h"
 #include "tapdisk-log.h"
 #include "tapdisk-utils.h"
 
diff --git a/tools/blktap2/drivers/tapdisk2.c b/tools/blktap2/drivers/tapdisk2.c
index 237b856dde..0eb10cb5e5 100644
--- a/tools/blktap2/drivers/tapdisk2.c
+++ b/tools/blktap2/drivers/tapdisk2.c
@@ -43,6 +43,7 @@
 #include "tapdisk-vbd.h"
 #include "tapdisk-utils.h"
 #include "tapdisk-server.h"
+#include "tapdisk-disktype.h"
 
 #define TAPDISK2_VBD 0
 
@@ -327,7 +328,7 @@ tapdisk2_set_child_fds(void)
 static int
 tapdisk2_create_device(const char *params)
 {
-	char *path;
+	const char *path;
 	int err, type;
 
 	chdir("/");