vold/devmapper.c - third_party/android/platform/system/core - Git at Google


 /*
  * Copyright (C) 2008 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 #include <dirent.h>
 #include <unistd.h>
 #include <sched.h>
 #include <fcntl.h>

 #include <sys/mount.h>

 #include <linux/loop.h>
 #include <linux/dm-ioctl.h>

 #include <cutils/config_utils.h>
 #include <cutils/properties.h>

 #include "vold.h"
 #include "devmapper.h"

 #define DEBUG_DEVMAPPER 1

 static void *_align(void *ptr, unsigned int a)
 {
         register unsigned long agn = --a;

         return (void *) (((unsigned long) ptr + agn) & ~agn);
 }

 static struct dm_ioctl *_dm_ioctl_setup(struct devmapping *dm, int flags)
 {
     void *buffer;
     void *p;
     const size_t min_size = 16 * 1024;
     size_t len = sizeof(struct dm_ioctl);
     struct dm_ioctl *io;
     struct dm_target_spec *tgt;
     int i;
     char params[1024];
     char key[80];

     key[0] = '\0';
     for (i = 0; i < (int) sizeof(dm->key); i++) {
         char tmp[8];

         sprintf(tmp, "%02x", dm->key[i]);
         strcat(key, tmp);
     }

     char srcdev[128];

     // XXX: Handle non crypt targets and non twofish (use param)
     if (dm->src_type == dmsrc_loopback)
         strcpy(srcdev, dm->type_data.loop.loop_dev);
     else if (dm->src_type == dmsrc_partition)
         strcpy(srcdev, dm->type_data.part.part_dev);

     sprintf(params, "twofish %s 0 %s 0", key, srcdev);

 LOG_VOL("Params = '%s'", params);

     if (len < min_size)
         len = min_size;

     if (!(buffer = malloc(len))) {
         LOGE("out of memory");
         return NULL;
     }

     memset(buffer, 0, len);
     io = buffer;
     tgt = (struct dm_target_spec *) &buffer[sizeof(struct dm_ioctl)];

     io->version[0] = 4;
     io->version[1] = 0;
     io->version[2] = 0;

     io->data_size = len;
     io->data_start = sizeof(struct dm_ioctl);

     io->flags = flags;
     io->dev = 0;

     io->target_count = 1;
     io->event_nr = 1;
     strncpy(io->name, dm->target, sizeof(io->name));

     tgt->status = 0;
     tgt->sector_start = 0;
     tgt->length = (dm->size_mb * (1024 * 1024)) / 512;
     strncpy(tgt->target_type, "crypt", sizeof(tgt->target_type));

     p = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec);
     strcpy((char *) p, params);
     p+= strlen(params) + 1;

     p = _align(p, 8);
     tgt->next = p - buffer;

     return io;
 }

 static int get_next_available_dm()
 {
     int i;

     for (i = 0; i < 8; i++) {
         char path[255];
         sprintf(path, "/dev/block/dm-%d", i);
         if ((access(path, F_OK) < 0) && (errno == ENOENT))
             return i;
     }

     LOGE("Out of device mapper numbers");
     return -1;
 }

 static int create_devmapping(struct devmapping *dm)
 {
     struct dm_ioctl *io;
     int rc, fd;

 #if DEBUG_DEVMAPPER
     LOG_VOL("create_devmapping():");
 #endif

     if (dm->dm_no < 0) {
         LOGE("Invalid dm_no set");
         return -EINVAL;
     }

     if ((fd = open("/dev/device-mapper", O_RDWR)) < 0) {
         LOGE("Error opening device mapper (%d)", errno);
         return -errno;
     }

     if (!(io = _dm_ioctl_setup(dm, 0))) {
         LOGE("Unable to setup ioctl (out of memory)");
         close(fd);
         return -ENOMEM;
     }

     if ((rc = ioctl(fd, DM_DEV_CREATE, io)) < 0) {
         LOGE("device-mapper create ioctl failed (%d)", errno);
         rc = -errno;
         goto out_free;
     }

     free(io);

     if (!(io = _dm_ioctl_setup(dm, DM_STATUS_TABLE_FLAG))) {
         LOGE("Unable to setup ioctl (out of memory)");
         rc = -ENOMEM;
         goto out_nofree;
     }

     if ((rc = ioctl(fd, DM_TABLE_LOAD, io)) < 0) {
         LOGE("device-mapper load ioctl failed (%d)", errno);
         rc = -errno;
         goto out_free;
     }

     free(io);

     if (!(io = _dm_ioctl_setup(dm, 0))) {
         LOGE("Unable to setup ioctl (out of memory)");
         rc = -ENOMEM;
         goto out_nofree;
     }

     if ((rc = ioctl(fd, DM_DEV_SUSPEND, io)) < 0) {
         LOGE("device-mapper resume ioctl failed (%d)", errno);
         rc = -errno;
         goto out_free;
     }

 out_free:
     free (io);
 out_nofree:
     close (fd);
     return rc;
 }

 static int loopback_start(struct devmapping *dm)
 {
     int i;
     int fd;
     char filename[255];
     int rc;

 #if DEBUG_DEVMAPPER
     LOG_VOL("loopback_start(%s):", dm->type_data.loop.loop_src);
 #endif

     for (i = 0; i < MAX_LOOP; i++) {
         struct loop_info info;

         sprintf(filename, "/dev/block/loop%d", i);

         if ((fd = open(filename, O_RDWR)) < 0) {
             LOGE("Unable to open %s (%s)", filename, strerror(errno));
             return -errno;
         }

         rc = ioctl(fd, LOOP_GET_STATUS, &info);
         if (rc < 0 && errno == ENXIO)
             break;

         close(fd);

         if (rc < 0) {
             LOGE("Unable to get loop status for %s (%s)", filename,
                  strerror(errno));
             return -errno;
         }
     }

     if (i == MAX_LOOP) {
         LOGE("Out of loop devices");
         return -ENOSPC;
     }

     int file_fd;

     if ((file_fd = open(dm->type_data.loop.loop_src, O_RDWR)) < 0) {
         LOGE("Unable to open %s (%s)", dm->type_data.loop.loop_src,
              strerror(errno));
         return -errno;
     }

     if (ioctl(fd, LOOP_SET_FD, file_fd) < 0) {
         LOGE("Error setting up loopback interface (%s)", strerror(errno));
         return -errno;
     }

     dm->type_data.loop.loop_dev = strdup(filename);
     dm->type_data.loop.loop_no  = i;

     close(fd);
     close(file_fd);

 #if DEBUG_DEVMAPPER
     LOG_VOL("Loop setup on %s for %s", dm->type_data.loop.loop_dev,
             dm->type_data.loop.loop_src);
 #endif

     return 0;
 }

 int devmapper_start(struct devmapping *dm)
 {
     int rc;
     char src_blkdev_path[255];

 #if DEBUG_DEVMAPPER
     LOG_VOL("devmapper_start()");
 #endif

     if (dm->src_type == dmsrc_loopback) {
        if ((rc = loopback_start(dm)) < 0)
            return rc;
     } else if (dm->src_type == dmsrc_partition) {
         LOGE("partition maps not yet supported");
         return -ENOSYS;
     } else {
         LOGE("devmapper_start(): Unsupported source type '%d'", dm->src_type);
         return -ENOENT;
     }

     /*
      * Configure the device mapper
      */
     if ((rc = create_devmapping(dm)) < 0) {
         LOGE("Failed to create devmapping (%d)", rc);
         // XXX: if loopback then tear down
         return rc;
     }

     return 0;
 }

 struct devmapping *devmapper_init(char *src, char *src_type, uint32_t size_mb,
                   char *target, char *params, char *tgt_fs, char *mediapath)
 {
     struct devmapping *dm;

     if (!(dm = malloc(sizeof(struct devmapping)))) {
         LOGE("devmapper_init(): out of memory");
         return NULL;
     }

     memset(dm, 0, sizeof(struct devmapping));

     if (!strcmp(src_type, "loopback_file")) {
         dm->src_type = dmsrc_loopback;
         dm->type_data.loop.loop_src = strdup(src);
     } else if (!strncmp(src_type, "partition ", strlen("partition "))) {
         dm->src_type = dmsrc_partition;
         char *p = strtok(src_type, " ");
         if (!p) {
             LOGE("Invalid partition specifier");
             goto out_free;
         }
         dm->type_data.part.part_type = strtoul(p, NULL, 0);
     } else {
         LOGE("Invalid src_type defined (%s)", src_type);
         goto out_free;
     }

     // XXX: Validate these
     dm->size_mb = size_mb;
     dm->target = strdup(target);
     dm->params = strdup(params);
     dm->tgt_fs = strdup(tgt_fs);

     if ((dm->dm_no = get_next_available_dm()) < 0)
         goto out_free;

     sprintf(mediapath, "/devices/virtual/block/dm-%d", dm->dm_no);

     if (!(dm->media = media_create(mediapath,
                                    "unknown",
                                    "unknown",
                                    media_devmapper))) {
         LOGE("Unable to create media");
         goto out_free;
     }

     return dm;
  out_free:
     if (dm->target)
         free(dm->target);
     if (dm->params)
         free(dm->params);
     if (dm->tgt_fs)
         free(dm->tgt_fs);

     free(dm);
     return NULL;
 }

 int devmapper_genesis(struct devmapping *dm)
 {

     if (dm->src_type == dmsrc_loopback) {
         int fd;

         LOG_VOL("devmapper_genesis(): Working on %s",
                 dm->type_data.loop.loop_src);

         unlink(dm->type_data.loop.loop_src);

         LOG_VOL("devmapper_genesis(): Creating imagefile (%u MB)",
                 dm->size_mb);

         if ((fd = creat(dm->type_data.loop.loop_src, 0600)) < 0) {
             LOGE("Error creating imagefile (%s)", strerror(errno));
             return -errno;
         }

         if (ftruncate(fd, (dm->size_mb * (1024 * 1024))) < 0) {
             LOGE("Error truncating imagefile (%s)", strerror(errno));
             close(fd);
             return -errno;
         }
         close(fd);
     } else if (dm->src_type == dmsrc_partition) {
         LOGE("partition maps not yet supported");
         return -ENOSYS;
     }

     return devmapper_start(dm);
 }

 static int destroy_devmapping(struct devmapping *dm)
 {
     struct dm_ioctl       *io;
     int                   dmFd;
     int                   rc = 0;

     LOG_VOL("destroy_devmapping():");

     if ((dmFd = open("/dev/device-mapper", O_RDWR)) < 0) {
         LOGE("Error opening device mapper (%d)", errno);
         return -errno;
     }

     if (!(io = _dm_ioctl_setup(dm, DM_PERSISTENT_DEV_FLAG))) {
         LOGE("Unable to setup ioctl (out of memory)");
         rc = -ENOMEM;
         goto out_nofree;
     }

     if ((rc = ioctl(dmFd, DM_DEV_REMOVE, io)) < 0) {
         LOGE("device-mapper remove ioctl failed (%d)", errno);
         rc = -errno;
         goto out_free;
     }

 out_free:
     free (io);
 out_nofree:
     close (dmFd);
     return rc;
 }

 static int loopback_stop(struct devmapping *dm)
 {
     char devname[255];
     int device_fd;
     int rc = 0;

     LOG_VOL("loopback_stop():");

     device_fd = open(dm->type_data.loop.loop_dev, O_RDONLY);
     if (device_fd < 0) {
         LOG_ERROR("Failed to open loop (%d)", errno);
         return -errno;
     }

     if (ioctl(device_fd, LOOP_CLR_FD, 0) < 0) {
         LOG_ERROR("Failed to destroy loop (%d)", errno);
         rc = -errno;
     }

     close(device_fd);
     return rc;
 }

 int devmapper_stop(struct devmapping *dm)
 {
     int rc;

     LOG_VOL("devmapper_stop():");

     if ((rc = destroy_devmapping(dm)))
         return rc;

     if (dm->src_type == dmsrc_loopback) {
         if ((rc = loopback_stop(dm)))
             return rc;
     } else if (dm->src_type == dmsrc_partition) {
         LOGE("partition maps not yet supported");
         return -ENOSYS;
     }
     return 0;
 }

	/*
	* Copyright (C) 2008 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <stdlib.h>
	#include <string.h>
	#include <errno.h>
	#include <dirent.h>
	#include <unistd.h>
	#include <sched.h>
	#include <fcntl.h>

	#include <sys/mount.h>

	#include <linux/loop.h>
	#include <linux/dm-ioctl.h>

	#include <cutils/config_utils.h>
	#include <cutils/properties.h>

	#include "vold.h"
	#include "devmapper.h"

	#define DEBUG_DEVMAPPER 1

	static void _align(void ptr, unsigned int a)
	{
	register unsigned long agn = --a;

	return (void *) (((unsigned long) ptr + agn) & ~agn);
	}

	static struct dm_ioctl _dm_ioctl_setup(struct devmapping dm, int flags)
	{
	void *buffer;
	void *p;
	const size_t min_size = 16 * 1024;
	size_t len = sizeof(struct dm_ioctl);
	struct dm_ioctl *io;
	struct dm_target_spec *tgt;
	int i;
	char params[1024];
	char key[80];

	key[0] = '\0';
	for (i = 0; i < (int) sizeof(dm->key); i++) {
	char tmp[8];

	sprintf(tmp, "%02x", dm->key[i]);
	strcat(key, tmp);
	}

	char srcdev[128];

	// XXX: Handle non crypt targets and non twofish (use param)
	if (dm->src_type == dmsrc_loopback)
	strcpy(srcdev, dm->type_data.loop.loop_dev);
	else if (dm->src_type == dmsrc_partition)
	strcpy(srcdev, dm->type_data.part.part_dev);

	sprintf(params, "twofish %s 0 %s 0", key, srcdev);

	LOG_VOL("Params = '%s'", params);

	if (len < min_size)
	len = min_size;

	if (!(buffer = malloc(len))) {
	LOGE("out of memory");
	return NULL;
	}

	memset(buffer, 0, len);
	io = buffer;
	tgt = (struct dm_target_spec *) &buffer[sizeof(struct dm_ioctl)];

	io->version[0] = 4;
	io->version[1] = 0;
	io->version[2] = 0;

	io->data_size = len;
	io->data_start = sizeof(struct dm_ioctl);

	io->flags = flags;
	io->dev = 0;

	io->target_count = 1;
	io->event_nr = 1;
	strncpy(io->name, dm->target, sizeof(io->name));

	tgt->status = 0;
	tgt->sector_start = 0;
	tgt->length = (dm->size_mb * (1024 * 1024)) / 512;
	strncpy(tgt->target_type, "crypt", sizeof(tgt->target_type));

	p = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec);
	strcpy((char *) p, params);
	p+= strlen(params) + 1;

	p = _align(p, 8);
	tgt->next = p - buffer;

	return io;
	}

	static int get_next_available_dm()
	{
	int i;

	for (i = 0; i < 8; i++) {
	char path[255];
	sprintf(path, "/dev/block/dm-%d", i);
	if ((access(path, F_OK) < 0) && (errno == ENOENT))
	return i;
	}

	LOGE("Out of device mapper numbers");
	return -1;
	}

	static int create_devmapping(struct devmapping *dm)
	{
	struct dm_ioctl *io;
	int rc, fd;

	#if DEBUG_DEVMAPPER
	LOG_VOL("create_devmapping():");
	#endif

	if (dm->dm_no < 0) {
	LOGE("Invalid dm_no set");
	return -EINVAL;
	}

	if ((fd = open("/dev/device-mapper", O_RDWR)) < 0) {
	LOGE("Error opening device mapper (%d)", errno);
	return -errno;
	}

	if (!(io = _dm_ioctl_setup(dm, 0))) {
	LOGE("Unable to setup ioctl (out of memory)");
	close(fd);
	return -ENOMEM;
	}

	if ((rc = ioctl(fd, DM_DEV_CREATE, io)) < 0) {
	LOGE("device-mapper create ioctl failed (%d)", errno);
	rc = -errno;
	goto out_free;
	}

	free(io);

	if (!(io = _dm_ioctl_setup(dm, DM_STATUS_TABLE_FLAG))) {
	LOGE("Unable to setup ioctl (out of memory)");
	rc = -ENOMEM;
	goto out_nofree;
	}

	if ((rc = ioctl(fd, DM_TABLE_LOAD, io)) < 0) {
	LOGE("device-mapper load ioctl failed (%d)", errno);
	rc = -errno;
	goto out_free;
	}

	free(io);

	if (!(io = _dm_ioctl_setup(dm, 0))) {
	LOGE("Unable to setup ioctl (out of memory)");
	rc = -ENOMEM;
	goto out_nofree;
	}

	if ((rc = ioctl(fd, DM_DEV_SUSPEND, io)) < 0) {
	LOGE("device-mapper resume ioctl failed (%d)", errno);
	rc = -errno;
	goto out_free;
	}

	out_free:
	free (io);
	out_nofree:
	close (fd);
	return rc;
	}

	static int loopback_start(struct devmapping *dm)
	{
	int i;
	int fd;
	char filename[255];
	int rc;

	#if DEBUG_DEVMAPPER
	LOG_VOL("loopback_start(%s):", dm->type_data.loop.loop_src);
	#endif

	for (i = 0; i < MAX_LOOP; i++) {
	struct loop_info info;

	sprintf(filename, "/dev/block/loop%d", i);

	if ((fd = open(filename, O_RDWR)) < 0) {
	LOGE("Unable to open %s (%s)", filename, strerror(errno));
	return -errno;
	}

	rc = ioctl(fd, LOOP_GET_STATUS, &info);
	if (rc < 0 && errno == ENXIO)
	break;

	close(fd);

	if (rc < 0) {
	LOGE("Unable to get loop status for %s (%s)", filename,
	strerror(errno));
	return -errno;
	}
	}

	if (i == MAX_LOOP) {
	LOGE("Out of loop devices");
	return -ENOSPC;
	}

	int file_fd;

	if ((file_fd = open(dm->type_data.loop.loop_src, O_RDWR)) < 0) {
	LOGE("Unable to open %s (%s)", dm->type_data.loop.loop_src,
	strerror(errno));
	return -errno;
	}

	if (ioctl(fd, LOOP_SET_FD, file_fd) < 0) {
	LOGE("Error setting up loopback interface (%s)", strerror(errno));
	return -errno;
	}

	dm->type_data.loop.loop_dev = strdup(filename);
	dm->type_data.loop.loop_no = i;

	close(fd);
	close(file_fd);

	#if DEBUG_DEVMAPPER
	LOG_VOL("Loop setup on %s for %s", dm->type_data.loop.loop_dev,
	dm->type_data.loop.loop_src);
	#endif

	return 0;
	}

	int devmapper_start(struct devmapping *dm)
	{
	int rc;
	char src_blkdev_path[255];

	#if DEBUG_DEVMAPPER
	LOG_VOL("devmapper_start()");
	#endif

	if (dm->src_type == dmsrc_loopback) {
	if ((rc = loopback_start(dm)) < 0)
	return rc;
	} else if (dm->src_type == dmsrc_partition) {
	LOGE("partition maps not yet supported");
	return -ENOSYS;
	} else {
	LOGE("devmapper_start(): Unsupported source type '%d'", dm->src_type);
	return -ENOENT;
	}

	/*
	* Configure the device mapper
	*/
	if ((rc = create_devmapping(dm)) < 0) {
	LOGE("Failed to create devmapping (%d)", rc);
	// XXX: if loopback then tear down
	return rc;
	}

	return 0;
	}

	struct devmapping devmapper_init(char src, char *src_type, uint32_t size_mb,
	char target, char params, char tgt_fs, char mediapath)
	{
	struct devmapping *dm;

	if (!(dm = malloc(sizeof(struct devmapping)))) {
	LOGE("devmapper_init(): out of memory");
	return NULL;
	}

	memset(dm, 0, sizeof(struct devmapping));

	if (!strcmp(src_type, "loopback_file")) {
	dm->src_type = dmsrc_loopback;
	dm->type_data.loop.loop_src = strdup(src);
	} else if (!strncmp(src_type, "partition ", strlen("partition "))) {
	dm->src_type = dmsrc_partition;
	char *p = strtok(src_type, " ");
	if (!p) {
	LOGE("Invalid partition specifier");
	goto out_free;
	}
	dm->type_data.part.part_type = strtoul(p, NULL, 0);
	} else {
	LOGE("Invalid src_type defined (%s)", src_type);
	goto out_free;
	}

	// XXX: Validate these
	dm->size_mb = size_mb;
	dm->target = strdup(target);
	dm->params = strdup(params);
	dm->tgt_fs = strdup(tgt_fs);

	if ((dm->dm_no = get_next_available_dm()) < 0)
	goto out_free;

	sprintf(mediapath, "/devices/virtual/block/dm-%d", dm->dm_no);

	if (!(dm->media = media_create(mediapath,
	"unknown",
	"unknown",
	media_devmapper))) {
	LOGE("Unable to create media");
	goto out_free;
	}

	return dm;
	out_free:
	if (dm->target)
	free(dm->target);
	if (dm->params)
	free(dm->params);
	if (dm->tgt_fs)
	free(dm->tgt_fs);

	free(dm);
	return NULL;
	}

	int devmapper_genesis(struct devmapping *dm)
	{

	if (dm->src_type == dmsrc_loopback) {
	int fd;

	LOG_VOL("devmapper_genesis(): Working on %s",
	dm->type_data.loop.loop_src);

	unlink(dm->type_data.loop.loop_src);

	LOG_VOL("devmapper_genesis(): Creating imagefile (%u MB)",
	dm->size_mb);

	if ((fd = creat(dm->type_data.loop.loop_src, 0600)) < 0) {
	LOGE("Error creating imagefile (%s)", strerror(errno));
	return -errno;
	}

	if (ftruncate(fd, (dm->size_mb * (1024 * 1024))) < 0) {
	LOGE("Error truncating imagefile (%s)", strerror(errno));
	close(fd);
	return -errno;
	}
	close(fd);
	} else if (dm->src_type == dmsrc_partition) {
	LOGE("partition maps not yet supported");
	return -ENOSYS;
	}

	return devmapper_start(dm);
	}

	static int destroy_devmapping(struct devmapping *dm)
	{
	struct dm_ioctl *io;
	int dmFd;
	int rc = 0;

	LOG_VOL("destroy_devmapping():");

	if ((dmFd = open("/dev/device-mapper", O_RDWR)) < 0) {
	LOGE("Error opening device mapper (%d)", errno);
	return -errno;
	}

	if (!(io = _dm_ioctl_setup(dm, DM_PERSISTENT_DEV_FLAG))) {
	LOGE("Unable to setup ioctl (out of memory)");
	rc = -ENOMEM;
	goto out_nofree;
	}

	if ((rc = ioctl(dmFd, DM_DEV_REMOVE, io)) < 0) {
	LOGE("device-mapper remove ioctl failed (%d)", errno);
	rc = -errno;
	goto out_free;
	}

	out_free:
	free (io);
	out_nofree:
	close (dmFd);
	return rc;
	}

	static int loopback_stop(struct devmapping *dm)
	{
	char devname[255];
	int device_fd;
	int rc = 0;

	LOG_VOL("loopback_stop():");

	device_fd = open(dm->type_data.loop.loop_dev, O_RDONLY);
	if (device_fd < 0) {
	LOG_ERROR("Failed to open loop (%d)", errno);
	return -errno;
	}

	if (ioctl(device_fd, LOOP_CLR_FD, 0) < 0) {
	LOG_ERROR("Failed to destroy loop (%d)", errno);
	rc = -errno;
	}

	close(device_fd);
	return rc;
	}

	int devmapper_stop(struct devmapping *dm)
	{
	int rc;

	LOG_VOL("devmapper_stop():");

	if ((rc = destroy_devmapping(dm)))
	return rc;

	if (dm->src_type == dmsrc_loopback) {
	if ((rc = loopback_stop(dm)))
	return rc;
	} else if (dm->src_type == dmsrc_partition) {
	LOGE("partition maps not yet supported");
	return -ENOSYS;
	}
	return 0;
	}