[PATCH] Add complex block layout discovery and mapping daemon

[Jim Rees <rees@umich.edu>]

This is a replacement for the patch I sent 21 July, incorporating feedback
from list members.  Thank you for your comments.

I have tried to settle on "blkmapd" as the name and use it consistently for
the executable, service name, syslog, etc.

I did not change atomicio.c.  That's because this is a copy of the file by
the same name in both idmapd and spnfsd.  There is a patch in the works to
move this to the support library.  I think the right thing to do is move
that patch forward, then fix atomicio.

Signed-off-by: Jim Rees <rees@umich.edu>
---
 configure.ac                         |    4 +
 utils/Makefile.am                    |    4 +
 utils/blkmapd/Makefile.am            |   63 +++++
 utils/blkmapd/atomicio.c             |   54 ++++
 utils/blkmapd/cfg.c                  |  248 +++++++++++++++++
 utils/blkmapd/cfg.h                  |   47 +++
 utils/blkmapd/device-discovery.c     |  502 +++++++++++++++++++++++++++++++++
 utils/blkmapd/device-discovery.h     |  162 +++++++++++
 utils/blkmapd/device-inq.c           |  235 ++++++++++++++++
 utils/blkmapd/device-process.c       |  394 ++++++++++++++++++++++++++
 utils/blkmapd/dm-device.c            |  509 ++++++++++++++++++++++++++++++++++
 utils/blkmapd/etc/blkmapd.conf       |   10 +
 utils/blkmapd/etc/initd/initd.redhat |   76 +++++
 13 files changed, 2308 insertions(+), 0 deletions(-)
 create mode 100644 utils/blkmapd/Makefile.am
 create mode 100644 utils/blkmapd/atomicio.c
 create mode 100644 utils/blkmapd/cfg.c
 create mode 100644 utils/blkmapd/cfg.h
 create mode 100644 utils/blkmapd/device-discovery.c
 create mode 100644 utils/blkmapd/device-discovery.h
 create mode 100644 utils/blkmapd/device-inq.c
 create mode 100644 utils/blkmapd/device-process.c
 create mode 100644 utils/blkmapd/dm-device.c
 create mode 100644 utils/blkmapd/etc/blkmapd.conf
 create mode 100644 utils/blkmapd/etc/initd/initd.redhat

diff --git a/configure.ac b/configure.ac
index 4d12715..f57cd45 100644
--- a/configure.ac
+++ b/configure.ac
@@ -64,12 +64,15 @@ AC_ARG_ENABLE(nfsv4,
 	enable_nfsv4=yes)
 	if test "$enable_nfsv4" = yes; then
 		AC_DEFINE(NFS4_SUPPORTED, 1, [Define this if you want NFSv4 support compiled in])
+		BLKMAPD=blkmapd
 		IDMAPD=idmapd
 		SPNFSD=spnfsd
 	else
 		enable_nfsv4=
+		BLKMAPD=
 		IDMAPD=
 	fi
+	AC_SUBST(BLKMAPD)
 	AC_SUBST(IDMAPD)
 	AC_SUBST(enable_nfsv4)
 	AM_CONDITIONAL(CONFIG_NFSV4, [test "$enable_nfsv4" = "yes"])
@@ -429,6 +432,7 @@ AC_CONFIG_FILES([
 	tools/mountstats/Makefile
 	tools/nfs-iostat/Makefile
 	utils/Makefile
+	utils/blkmapd/Makefile
 	utils/exportfs/Makefile
 	utils/gssd/Makefile
 	utils/idmapd/Makefile
diff --git a/utils/Makefile.am b/utils/Makefile.am
index c777d21..c33835a 100644
--- a/utils/Makefile.am
+++ b/utils/Makefile.am
@@ -10,6 +10,10 @@ if CONFIG_NFSV4
 OPTDIRS += spnfsd
 endif
 
+if CONFIG_NFSV4
+OPTDIRS += blkmapd
+endif
+
 if CONFIG_GSS
 OPTDIRS += gssd
 endif
diff --git a/utils/blkmapd/Makefile.am b/utils/blkmapd/Makefile.am
new file mode 100644
index 0000000..81cc420
--- /dev/null
+++ b/utils/blkmapd/Makefile.am
@@ -0,0 +1,63 @@
+## Process this file with automake to produce Makefile.in
+
+#man8_MANS	= blkmapd.man
+
+AM_CFLAGS	+= -D_LARGEFILE64_SOURCE
+KPREFIX		= @kprefix@
+sbin_PROGRAMS	= blkmapd
+
+blkmapd_SOURCES = \
+	atomicio.c \
+	cfg.c \
+	device-discovery.c \
+	device-inq.c \
+	device-process.c \
+	dm-device.c \
+	\
+	cfg.h \
+	device-discovery.h
+
+blkmapd_LDADD = -ldevmapper ../../support/nfs/libnfs.a
+
+MAINTAINERCLEANFILES = Makefile.in
+
+#######################################################################
+# The following allows the current practice of having
+# daemons renamed during the install to include RPCPREFIX
+# and the KPREFIX
+# This could all be done much easier with program_transform_name
+# ( program_transform_name = s/^/$(RPCPREFIX)$(KPREFIX)/ )
+# but that also renames the man pages, which the current
+# practice does not do.
+install-exec-hook:
+	(cd $(DESTDIR)$(sbindir) && \
+	  for p in $(sbin_PROGRAMS); do \
+	    mv -f $$p$(EXEEXT) $(RPCPREFIX)$(KPREFIX)$$p$(EXEEXT) ;\
+	  done)
+uninstall-hook:
+	(cd $(DESTDIR)$(sbindir) && \
+	  for p in $(sbin_PROGRAMS); do \
+	    rm -f $(RPCPREFIX)$(KPREFIX)$$p$(EXEEXT) ;\
+	  done)
+
+
+# XXX This makes some assumptions about what automake does.
+# XXX But there is no install-man-hook or install-man-local.
+install-man: install-man8 install-man-links
+uninstall-man: uninstall-man8 uninstall-man-links
+
+install-man-links:
+	(cd $(DESTDIR)$(man8dir) && \
+	  for m in $(man8_MANS) $(dist_man8_MANS) $(nodist_man8_MANS); do \
+	    inst=`echo $$m | sed -e 's/man$$/8/'`; \
+	    rm -f $(RPCPREFIX)$$inst ; \
+	    $(LN_S) $$inst $(RPCPREFIX)$$inst ; \
+	  done)
+
+uninstall-man-links:
+	(cd $(DESTDIR)$(man8dir) && \
+	  for m in $(man8_MANS) $(dist_man8_MANS) $(nodist_man8_MANS); do \
+	    inst=`echo $$m | sed -e 's/man$$/8/'`; \
+	    rm -f $(RPCPREFIX)$$inst ; \
+	  done)
+
diff --git a/utils/blkmapd/atomicio.c b/utils/blkmapd/atomicio.c
new file mode 100644
index 0000000..8db626e
--- /dev/null
+++ b/utils/blkmapd/atomicio.c
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2002 Marius Aamodt Eriksen <marius@monkey.org>
+ * Copyright (c) 1995,1999 Theo de Raadt.  All rights reserved.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <sys/types.h>
+#include <unistd.h>
+#include <errno.h>
+
+/*
+ * ensure all of data on socket comes through. f==read || f==write
+ */
+ssize_t atomicio(ssize_t(*f) (int, void *, size_t), int fd, void *_s, size_t n)
+{
+	char *s = _s;
+	ssize_t res, pos = 0;
+
+	while (n > pos) {
+		res = (f) (fd, s + pos, n - pos);
+		switch (res) {
+		case -1:
+			if (errno == EINTR || errno == EAGAIN)
+				continue;
+		case 0:
+			if (pos != 0)
+				return pos;
+			return res;
+		default:
+			pos += res;
+		}
+	}
+	return pos;
+}
diff --git a/utils/blkmapd/cfg.c b/utils/blkmapd/cfg.c
new file mode 100644
index 0000000..dab9d0f
--- /dev/null
+++ b/utils/blkmapd/cfg.c
@@ -0,0 +1,248 @@
+/*
+ * Copyright (c) 2010 EMC Corporation, Haiying Tang <Tang_Haiying@emc.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <sys/param.h>
+#include <sys/stat.h>
+#include <linux/errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <ctype.h>
+
+#include "device-discovery.h"
+#include "cfg.h"
+
+char *conf_path = "/etc/blkmapd.conf";
+
+struct scan_root_list *scan_root_list_head;
+
+void bl_release_list(void)
+{
+	struct scan_root_list *root = scan_root_list_head;
+	struct scan_device_list *disk;
+
+	while (root) {
+		disk = root->disk;
+		while (disk) {
+			root->disk = disk->next;
+			free(disk->name);
+			free(disk);
+			disk = root->disk;
+		}
+		scan_root_list_head = root->next;
+		free(root->name);
+		free(root);
+		root = scan_root_list_head;
+	}
+}
+
+struct scan_root_list *bl_alloc_root_list(char *name, int all_disk)
+{
+	struct scan_root_list *root;
+
+	root = malloc(sizeof(struct scan_root_list));
+	if (!root)
+		goto nomem;
+
+	root->name = strdup(name);
+	if (!root->name)
+		goto nomem;
+	root->next = scan_root_list_head;
+	root->all_disk = all_disk;
+	scan_root_list_head = root;
+	return root;
+
+ nomem:
+	BL_LOG_ERR("%s: Out of memory!\n", __func__);
+	if (root)
+		free(root);
+	return NULL;
+}
+
+struct scan_device_list *bl_alloc_device_list(struct scan_root_list *root,
+					      char *name)
+{
+	struct scan_device_list *device;
+
+	device = malloc(sizeof(struct scan_device_list));
+	if (!device)
+		goto nomem;
+
+	device->name = strdup(name);
+	if (!device->name)
+		goto nomem;
+	device->next = root->disk;
+	root->disk = device;
+	return device;
+
+ nomem:
+	BL_LOG_ERR("%s: Out of memory!\n", __func__);
+	if (device)
+		free(device);
+	return NULL;
+}
+
+struct scan_device_list *bl_insert_device_list(struct scan_root_list *root,
+					       char *name)
+{
+	struct scan_device_list *device = root->disk;
+
+	/* Check whether this device has been inserted */
+	while (device) {
+		if (device->name && !strcmp(device->name, name))
+			return device;
+		device = device->next;
+	}
+
+	return bl_alloc_device_list(root, name);
+}
+
+struct scan_root_list *bl_insert_root_list(char *name, int all_disk)
+{
+	struct scan_root_list *root = scan_root_list_head;
+
+	/* Check whether this root has been inserted */
+	while (root) {
+		if (root->name && !strcmp(root->name, name))
+			return root;
+		root = root->next;
+	}
+
+	return bl_alloc_root_list(name, all_disk);
+}
+
+int bl_parse_line(char *line, struct scan_root_list **bl_root)
+{
+	char *root, *device, *end;
+
+	root = strdup(line);
+	end = root + strlen(line);
+
+	/* Skip comments */
+	if (*root == '#')
+		return 0;
+
+	/* Trim leading space */
+	while (*root != '\0' && isspace(*root))
+		root++;
+	if (*root == '\0')
+		return 0;
+
+	/* Trim trailing space and set "end" to last char */
+	while ((isspace(*end) || (*end == '\0')) && (end > root))
+		end--;
+
+	/* For lines ending with '/' or '/','*': add as a dir root */
+	if ((*end == '/') ||
+	    ((*end == '*') && (end - root >= 1) && (*(end - 1) == '/'))) {
+		if (*end == '*')
+			end--;
+		if (*end == '/')
+			end--;
+		*(end + 1) = '\0';
+		*bl_root = bl_insert_root_list(root, 1);
+		return 0;
+	}
+
+	/* Other lines: add as a device */
+	device = end;
+	while ((*device != '/') && (device > root))
+		device--;
+	if (device == root) {
+		BL_LOG_ERR("%s: invalid config line\n", __func__);
+		return -1;
+	}
+	*device = '\0';
+	*bl_root = bl_insert_root_list(root, 0);
+	if (*bl_root == NULL)
+		return -ENOMEM;
+	if (*end == '*')
+		end--;
+	*(end + 1) = '\0';
+	if (bl_insert_device_list(*bl_root, device + 1) == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+
+int bl_set_default_conf(void)
+{
+	struct scan_root_list *root = NULL;
+	int rv;
+
+	bl_release_list();
+	rv = bl_parse_line("/dev/sd*", &root);
+	if (rv < 0)
+		return rv;
+	rv = bl_parse_line("/dev/mapper/", &root);
+	return rv;
+}
+
+int bl_parse_conf(char *buf)
+{
+	char *tmp = buf, *line = buf, *end = buf + strlen(buf);
+	struct scan_root_list *bl_root = NULL;
+	int rv;
+
+	while (tmp < end) {
+		if (*tmp == '\n') {
+			*tmp = '\0';
+			rv = bl_parse_line(line, &bl_root);
+			if (rv < 0)
+				return rv;
+			line = tmp + 1;
+		}
+		tmp++;
+	}
+
+	return 0;
+}
+
+int bl_cfg_init(void)
+{
+	struct scan_root_list *root = NULL;
+	FILE *f = NULL;
+	char buf[PATH_MAX];
+	int rv = 0;
+
+	f = fopen(conf_path, "r");
+	if (f == NULL)
+		rv = bl_set_default_conf();
+	else {
+		while (fgets(buf, sizeof buf, f) != NULL) {
+			rv = bl_parse_line(buf, &root);
+			if (rv < 0)
+				break;
+		}
+	}
+	if (!scan_root_list_head)
+		rv = -EINVAL;
+
+	if (f)
+		fclose(f);
+	return rv;
+}
diff --git a/utils/blkmapd/cfg.h b/utils/blkmapd/cfg.h
new file mode 100644
index 0000000..b9bf930
--- /dev/null
+++ b/utils/blkmapd/cfg.h
@@ -0,0 +1,47 @@
+/*
+ * bl-cfg.h
+ *
+ * Copyright (c) 2010 EMC Corporation, Haiying Tang <Tang_Haiying@emc.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 BL_CFG_H
+#define BL_CFG_H
+
+extern char *conf_path;
+extern struct scan_root_list *scan_root_list_head;
+
+struct scan_device_list {
+	struct scan_device_list *next;
+	char *name;
+};
+
+struct scan_root_list {
+	struct scan_root_list *next;
+	unsigned int all_disk;
+	char *name;
+	struct scan_device_list *disk;
+};
+
+int bl_cfg_init(void);
+
+#endif
diff --git a/utils/blkmapd/device-discovery.c b/utils/blkmapd/device-discovery.c
new file mode 100644
index 0000000..f42ddc8
--- /dev/null
+++ b/utils/blkmapd/device-discovery.c
@@ -0,0 +1,502 @@
+/*
+ * device-discovery.c: main function, discovering device and processing
+ * pipe request from kernel.
+ *
+ * Copyright (c) 2010 EMC Corporation, Haiying Tang <Tang_Haiying@emc.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <dirent.h>
+#include <ctype.h>
+#include <linux/kdev_t.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/mount.h>
+#include <sys/select.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <libgen.h>
+#include <errno.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_ioctl.h>
+#include <scsi/sg.h>
+#include "device-discovery.h"
+#include "cfg.h"
+
+#define BL_PIPE_FILE	"/var/lib/nfs/rpc_pipefs/bl_device_pipe"
+#define PID_FILE	"/var/run/blkmapd.pid"
+
+struct bl_disk *visible_disk_list;
+
+struct bl_disk_path *bl_get_path(const char *filepath,
+				 struct bl_disk_path *paths)
+{
+	struct bl_disk_path *tmp = paths;
+	while (tmp) {
+		if (!strcmp(tmp->full_path, filepath))
+			break;
+		tmp = tmp->next;
+	}
+	return tmp;
+}
+
+/* Check whether valid_path is a substring(partition) of path */
+int bl_is_partition(struct bl_disk_path *valid_path, struct bl_disk_path *path)
+{
+	if (!strncmp(valid_path->full_path, path->full_path,
+		     strlen(valid_path->full_path)))
+		return 1;
+
+	return 0;
+}
+
+/*
+ * For multipath devices, devices state could be PASSIVE/ACTIVE/PSEUDO,
+ * where PSEUDO > ACTIVE > PASSIVE. Device with highest state is used to
+ * create pseudo device. So if state is higher, the device path needs to
+ * be updated.
+ * If device-mapper multipath support is a must, pseudo devices should
+ * exist for each multipath device. If not, active device path will be
+ * chosen for device creation.
+ * Treat partition as invalid path.
+ */
+int bl_update_path(struct bl_disk_path *path, enum bl_path_state_e state,
+		   struct bl_disk *disk)
+{
+	struct bl_disk_path *valid_path = disk->valid_path;
+
+	if (valid_path) {
+		if (valid_path->state >= state) {
+			if (bl_is_partition(valid_path, path))
+				return 0;
+		}
+	}
+	return 1;
+}
+
+void bl_release_disk(void)
+{
+	struct bl_disk *disk;
+	struct bl_disk_path *path = NULL;
+
+	while (visible_disk_list) {
+		disk = visible_disk_list;
+		path = disk->paths;
+		while (path) {
+			disk->paths = path->next;
+			free(path->full_path);
+			free(path);
+			path = disk->paths;
+		}
+		if (disk->serial)
+			free(disk->serial);
+		visible_disk_list = disk->next;
+		free(disk);
+	}
+}
+
+void bl_add_disk(char *filepath)
+{
+	struct bl_disk *disk = NULL;
+	int fd = 0;
+	struct stat sb;
+	off_t size = 0;
+	struct bl_serial *serial = NULL;
+	enum bl_path_state_e ap_state = BL_PATH_STATE_PASSIVE;
+	struct bl_disk_path *diskpath = NULL, *path = NULL;
+	dev_t dev;
+
+	BL_LOG_ERR("%s: %s\n", __func__, filepath);
+
+	fd = open(filepath, O_RDONLY | O_LARGEFILE);
+	if (fd < 0)
+		return;
+
+	if (fstat(fd, &sb)) {
+		close(fd);
+		return;
+	}
+
+	if (!sb.st_size)
+		ioctl(fd, BLKGETSIZE, &size);
+	else
+		size = sb.st_size;
+
+	if (!size) {
+		close(fd);
+		return;
+	}
+
+	dev = sb.st_rdev;
+	serial = bldev_read_serial(fd, filepath);
+
+	for (disk = visible_disk_list; disk != NULL; disk = disk->next) {
+		/* Already scanned or a partition?
+		 * XXX: if released each time, maybe not need to compare
+		 */
+		if ((serial->len == disk->serial->len) &&
+		    !memcmp(serial->data, disk->serial->data, serial->len)) {
+			diskpath = bl_get_path(filepath, disk->paths);
+			break;
+		}
+	}
+
+	if (disk && diskpath) {
+		close(fd);
+		return;
+	}
+
+	bldev_read_ap_state(fd, &ap_state);
+	close(fd);
+
+	/*
+	 * Not sure how to identify a pseudo device created by
+	 * device-mapper, so leave /dev/mapper for now.
+	 */
+	if (strncmp(filepath, "/dev/mapper", 11) == 0)
+		ap_state = BL_PATH_STATE_PSEUDO;
+
+	/* add path */
+	path = malloc(sizeof(struct bl_disk_path));
+	if (!path) {
+		BL_LOG_ERR("%s: Out of memory!\n", __func__);
+		goto out_err;
+	}
+	path->next = NULL;
+	path->state = ap_state;
+	path->full_path = strdup(filepath);
+	if (!path->full_path)
+		goto out_err;
+
+	if (!disk) {		/* add disk */
+		disk = malloc(sizeof(struct bl_disk));
+		if (!disk) {
+			BL_LOG_ERR("%s: Out of memory!\n", __func__);
+			goto out_err;
+		}
+		disk->next = visible_disk_list;
+		disk->dev = dev;
+		disk->size = size;
+		disk->serial = serial;
+		disk->valid_path = path;
+		disk->paths = path;
+		visible_disk_list = disk;
+	} else {
+		path->next = disk->paths;
+		disk->paths = path;
+		/* check whether we need to update disk info */
+		if (bl_update_path(path, path->state, disk)) {
+			disk->dev = dev;
+			disk->size = size;
+			disk->valid_path = path;
+		}
+	}
+	return;
+
+ out_err:
+	if (path) {
+		if (path->full_path)
+			free(path->full_path);
+		free(path);
+	}
+	return;
+}
+
+void bl_devicescan(const char *filename, struct scan_root_list *root)
+{
+	/* scan all disks */
+	char filepath[PATH_MAX];
+	struct scan_device_list *device;
+
+	if (!strcmp(filename, ".") || !strcmp(filename, ".."))
+		return;
+
+	memset(filepath, 0, sizeof(filepath));
+	if (strlen(filename) < (PATH_MAX - strlen(root->name) - 2))
+		sprintf(filepath, "%s/%s", root->name, filename);
+	else {
+		BL_LOG_ERR("%s: name too long\n", __func__);
+		return;
+	}
+	if (root->all_disk)
+		goto valid;
+
+	device = root->disk;
+	while (device) {
+		/* If device->name is a subset of filename, this disk should be
+		 * valid for scanning.
+		 * For example, device->name is "sd", filename is "sda".
+		 */
+		if (device->name
+		    && !memcmp(filename, device->name, strlen(device->name)))
+			goto valid;
+		device = device->next;
+	}
+
+	return;
+
+ valid:
+	/*
+	 * sg device is not a real device, but a device created according
+	 * to each scsi device. It won't be used for pseudo device creation.
+	 * I moved it here, so that sg devices will not be scanned.
+	 */
+	if (!strncmp(filepath, "/dev/sg", 7))
+		return;
+	bl_add_disk(filepath);
+	return;
+}
+
+int bl_discover_devices(void)
+{
+	DIR *dir;
+	struct dirent *dp;
+	struct scan_root_list *root = scan_root_list_head;
+
+	/* release previous list */
+	bl_release_disk();
+
+	/* scan all disks */
+	while (root) {
+		dir = opendir(root->name);
+		if (dir == NULL) {
+			root = root->next;
+			continue;
+		}
+
+		while ((dp = readdir(dir)) != NULL)
+			bl_devicescan(dp->d_name, root);
+
+		root = root->next;
+		closedir(dir);
+	}
+
+	return 0;
+}
+
+/* process kernel request
+ * return 0: request processed, and no more request waiting;
+ * return 1: request processed, and more requests waiting;
+ * return < 0: error
+ */
+int bl_disk_inquiry_process(int fd)
+{
+	int ret = 0;
+	struct pipefs_hdr *head = NULL, *tmp;
+	char *buf = NULL;
+	uint32_t major, minor;
+	uint16_t buflen;
+	unsigned int len = 0;
+
+	head = calloc(1, sizeof(struct pipefs_hdr));
+	if (!head) {
+		BL_LOG_ERR("%s: Out of memory!\n", __func__);
+		return -ENOMEM;
+	}
+
+	/* read request */
+	if (atomicio(read, fd, head, sizeof(*head)) != sizeof(*head)) {
+		/* Note that an error in this or the next read is pretty
+		 * catastrophic, as there is no good way to resync into
+		 * the pipe's stream.
+		 */
+		BL_LOG_ERR("Read pipefs head error!\n");
+		ret = -EIO;
+		goto out;
+	}
+
+	buflen = head->totallen - sizeof(*head);
+	buf = malloc(buflen);
+	if (!buf) {
+		BL_LOG_ERR("%s: Out of memory!\n", __func__);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	if (atomicio(read, fd, buf, buflen) != buflen) {
+		BL_LOG_ERR("Read pipefs content error!\n");
+		ret = -EIO;
+		goto out;
+	}
+
+	head->status = BL_DEVICE_REQUEST_PROC;
+	switch (head->type) {
+	case BL_DEVICE_MOUNT:
+		if (!process_deviceinfo(buf, buflen, &major, &minor)) {
+			head->status = BL_DEVICE_REQUEST_ERR;
+			goto out;
+		}
+		tmp = realloc(head, sizeof(major) + sizeof(minor) +
+			      sizeof(struct pipefs_hdr));
+		if (!tmp) {
+			BL_LOG_ERR("%s: Out of memory!\n", __func__);
+			ret = -ENOMEM;
+			goto out;
+		}
+		head = tmp;
+		memcpy((void *)head + sizeof(struct pipefs_hdr),
+		       &major, sizeof(major));
+		memcpy((void *)head + sizeof(struct pipefs_hdr) + sizeof(major),
+		       &minor, sizeof(minor));
+		len = sizeof(major) + sizeof(minor);
+		break;
+	case BL_DEVICE_UMOUNT:
+		if (!dm_device_remove_all((uint64_t *) buf))
+			head->status = BL_DEVICE_REQUEST_ERR;
+		bl_discover_devices();
+		break;
+	default:
+		head->status = BL_DEVICE_REQUEST_ERR;
+	}
+
+	head->totallen = sizeof(struct pipefs_hdr) + len;
+	/* write to pipefs */
+	if (atomicio((void *)write, fd, head, head->totallen)
+	    != head->totallen) {
+		BL_LOG_ERR("Write pipefs error!\n");
+		ret = -EIO;
+	}
+
+ out:
+	if (buf)
+		free(buf);
+	if (head)
+		free(head);
+	return ret;
+}
+
+/* TODO: set bl_process_stop to 1 in command */
+unsigned int bl_process_stop;
+
+int bl_run_disk_inquiry_process(int fd)
+{
+	fd_set rset;
+	struct timeval tv;
+	int ret;
+
+	bl_process_stop = 0;
+
+	for (;;) {
+		if (bl_process_stop)
+			return 1;
+		FD_ZERO(&rset);
+		FD_SET(fd, &rset);
+		ret = 0;
+		tv.tv_sec = BL_DEVICE_DISCOVERY_INTERVAL;
+		switch (select(fd + 1, &rset, NULL, NULL, &tv)) {
+		case -1:
+			if (errno == EINTR)
+				continue;
+			else {
+				ret = -errno;
+				goto out;
+			}
+		case 0:
+			goto out;
+		default:
+			if (FD_ISSET(fd, &rset))
+				ret = bl_disk_inquiry_process(fd);
+		}
+	}
+ out:
+	return ret;
+}
+
+/* Daemon */
+int main(int argc, char **argv)
+{
+	int fd, opt, fg = 0, ret = 1;
+	struct stat statbuf;
+	char pidbuf[64];
+
+	while ((opt = getopt(argc, argv, "c:f")) != -1) {
+		switch (opt) {
+		case 'c':
+			conf_path = optarg;
+			break;
+		case 'f':
+			fg = 1;
+			break;
+		}
+	}
+
+	if (!stat(PID_FILE, &statbuf)) {
+		fprintf(stderr, "Pid file already existed\n");
+		return -1;
+	}
+
+	if (!fg && daemon(0, 0) != 0) {
+		fprintf(stderr, "Daemonize failed\n");
+		return -1;
+	}
+
+	openlog("blkmapd", LOG_PID, 0);
+	fd = open(PID_FILE, O_WRONLY | O_CREAT, 0644);
+	if (fd < 0) {
+		BL_LOG_ERR("Create pid file failed\n");
+		return -1;
+	}
+
+	if (lockf(fd, F_TLOCK, 0) < 0) {
+		BL_LOG_ERR("Lock pid file failed\n");
+		close(fd);
+		return -1;
+	}
+	ftruncate(fd, 0);
+	sprintf(pidbuf, "%d\n", getpid());
+	write(fd, pidbuf, strlen(pidbuf));
+
+	/* open pipe file */
+	fd = open(BL_PIPE_FILE, O_RDWR);
+	if (fd < 0) {
+		BL_LOG_ERR("open pipe file error\n");
+		return -1;
+	}
+
+	ret = bl_cfg_init();
+	if (ret < 0) {
+		if (ret == -ENOENT)
+			BL_LOG_WARNING("Config file not exist, use default\n");
+		else {
+			BL_LOG_ERR("Open/read Block pNFS config file error\n");
+			return -1;
+		}
+	}
+
+	while (1) {
+		/* discover device when needed */
+		bl_discover_devices();
+
+		ret = bl_run_disk_inquiry_process(fd);
+		if (ret < 0) {
+			/* what should we do with process error? */
+			BL_LOG_ERR("inquiry process return %d\n", ret);
+		}
+	}
+	close(fd);
+	return ret;
+}
diff --git a/utils/blkmapd/device-discovery.h b/utils/blkmapd/device-discovery.h
new file mode 100644
index 0000000..9f87ebe
--- /dev/null
+++ b/utils/blkmapd/device-discovery.h
@@ -0,0 +1,162 @@
+/*
+ * bl-device-discovery.h
+ *
+ * Copyright (c) 2010 EMC Corporation, Haiying Tang <Tang_Haiying@emc.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 BL_DEVICE_DISCOVERY_H
+#define BL_DEVICE_DISCOVERY_H
+
+#define BL_DEVICE_DISCOVERY_INTERVAL 60
+
+#include <stdint.h>
+#include <syslog.h>
+
+enum blk_vol_type {
+	BLOCK_VOLUME_SIMPLE = 0,	/* maps to a single LU */
+	BLOCK_VOLUME_SLICE = 1,	/* slice of another volume */
+	BLOCK_VOLUME_CONCAT = 2,	/* concatenation of multiple volumes */
+	BLOCK_VOLUME_STRIPE = 3,	/* striped across multiple volumes */
+	BLOCK_VOLUME_PSEUDO = 4,
+};
+
+/* All disk offset/lengths are stored in 512-byte sectors */
+struct bl_volume {
+	uint32_t bv_type;
+	off_t bv_size;
+	struct bl_volume **bv_vols;
+	int bv_vol_n;
+	union {
+		dev_t bv_dev;	/*for BLOCK_VOLUME_SIMPLE(PSEUDO) */
+		off_t bv_stripe_unit;	/*for BLOCK_VOLUME_STRIPE(CONCAT) */
+		off_t bv_offset;	/*for BLOCK_VOLUME_SLICE */
+	} param;
+};
+
+struct bl_sig_comp {
+	int64_t bs_offset;	/* In bytes */
+	uint32_t bs_length;	/* In bytes */
+	char *bs_string;
+};
+
+/* Maximum number of signatures components in a simple volume */
+# define BLOCK_MAX_SIG_COMP 16
+
+struct bl_sig {
+	int si_num_comps;
+	struct bl_sig_comp si_comps[BLOCK_MAX_SIG_COMP];
+};
+
+/*
+ * Multipath support: ACTIVE or PSEUDO device is valid,
+ *		      PASSIVE is a standby for ACTIVE.
+ */
+enum bl_path_state_e {
+	BL_PATH_STATE_PASSIVE = 1,
+	BL_PATH_STATE_ACTIVE = 2,
+	BL_PATH_STATE_PSEUDO = 3,
+};
+
+struct bl_serial {
+	int len;
+	char *data;
+};
+
+struct bl_disk_path {
+	struct bl_disk_path *next;
+	char *full_path;
+	enum bl_path_state_e state;
+};
+
+struct bl_disk {
+	struct bl_disk *next;
+	struct bl_serial *serial;
+	dev_t dev;
+	off_t size;
+	struct bl_disk_path *valid_path;
+	struct bl_disk_path *paths;
+};
+
+struct bl_dev_id {
+	unsigned char type;
+	unsigned char ids;
+	unsigned char reserve;
+	unsigned char len;
+	char data[0];
+};
+
+struct pipefs_hdr {
+	uint32_t msgid;
+	uint8_t type;
+	uint8_t flags;
+	uint16_t totallen;	/* length of entire message, including hdr */
+	uint32_t status;
+};
+
+#define BL_DEVICE_UMOUNT                0x0	/* Umount--delete devices */
+#define BL_DEVICE_MOUNT                 0x1	/* Mount--create devices */
+#define BL_DEVICE_REQUEST_INIT          0x0	/* Start request */
+#define BL_DEVICE_REQUEST_PROC          0x1	/* User process succeeds */
+#define BL_DEVICE_REQUEST_ERR           0x2	/* User process fails */
+
+uint32_t *blk_overflow(uint32_t * p, uint32_t * end, size_t nbytes);
+
+#define BLK_READBUF(p, e, nbytes)  do { \
+	p = blk_overflow(p, e, nbytes); \
+	if (!p) {\
+		goto out_err;\
+	} \
+} while (0)
+
+#define READ32(x)         (x) = ntohl(*p++)
+
+#define READ64(x)         do {                  \
+	(x) = (uint64_t)ntohl(*p++) << 32;           \
+	(x) |= ntohl(*p++);                     \
+} while (0)
+
+#define READ_SECTOR(x)     do { \
+	READ64(tmp); \
+	if (tmp & 0x1ff) { \
+		goto out_err; \
+	} \
+	(x) = tmp >> 9; \
+} while (0)
+
+extern struct bl_disk *visible_disk_list;
+uint64_t dm_device_create(struct bl_volume *vols, int num_vols);
+int dm_device_remove_all(uint64_t *dev);
+uint64_t process_deviceinfo(const char *dev_addr_buf,
+			    unsigned int dev_addr_len,
+			    uint32_t *major, uint32_t *minor);
+
+extern ssize_t atomicio(ssize_t(*f) (int, void *, size_t),
+			int fd, void *_s, size_t n);
+extern struct bl_serial *bldev_read_serial(int fd, const char *filename);
+extern void bldev_read_ap_state(int fd, enum bl_path_state_e *ap_state_out);
+extern int bl_discover_devices(void);
+
+#define BL_LOG_WARNING(fmt...)		syslog(LOG_WARNING, fmt)
+#define BL_LOG_ERR(fmt...)		syslog(LOG_ERR, fmt)
+#define BL_LOG_DEBUG(fmt...)		syslog(LOG_DEBUG, fmt)
+#endif
diff --git a/utils/blkmapd/device-inq.c b/utils/blkmapd/device-inq.c
new file mode 100644
index 0000000..ff38fd6
--- /dev/null
+++ b/utils/blkmapd/device-inq.c
@@ -0,0 +1,235 @@
+/*
+ * device-inq.c: inquire SCSI device information.
+ *
+ * Copyright (c) 2010 EMC Corporation, Haiying Tang <Tang_Haiying@emc.com>
+ * All rights reserved.
+ *
+ * This program refers to "SCSI Primary Commands - 3 (SPC-3)
+ * at http://www.t10.org and sg_inq.c in sg3_utils-1.26 for
+ * Linux OS SCSI subsystem, by D. Gilbert.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <dirent.h>
+#include <ctype.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/mount.h>
+#include <sys/select.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <libgen.h>
+#include <errno.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_ioctl.h>
+#include <scsi/sg.h>
+#include "device-discovery.h"
+
+#define DEF_ALLOC_LEN	255
+#define MX_ALLOC_LEN	(0xc000 + 0x80)
+
+struct bl_serial *bl_create_scsi_string(int len, const char *bytes)
+{
+	struct bl_serial *s;
+	s = malloc(sizeof(*s) + len);
+	if (s) {
+		s->data = (char *)&s[1];
+		s->len = len;
+		memcpy(s->data, bytes, len);
+	}
+	return s;
+}
+
+void bl_free_scsi_string(struct bl_serial *str)
+{
+	if (str)
+		free(str);
+}
+
+#define sg_io_ok(io_hdr) \
+	((((io_hdr).status & 0x7e) == 0) && \
+	((io_hdr).host_status == 0) && \
+	(((io_hdr).driver_status & 0x0f) == 0))
+
+static int sg_timeout = 1 * 1000;
+
+static int bldev_inquire_page(int fd, int page, char *buffer, int len)
+{
+	unsigned char cmd[] = { INQUIRY, 0, 0, 0, 0, 0 };
+	unsigned char sense_b[28];
+	struct sg_io_hdr io_hdr;
+	if (page >= 0) {
+		cmd[1] = 1;
+		cmd[2] = page;
+	}
+	cmd[3] = (unsigned char)((len >> 8) & 0xff);
+	cmd[4] = (unsigned char)(len & 0xff);
+
+	memset(&io_hdr, 0, sizeof(struct sg_io_hdr));
+	io_hdr.interface_id = 'S';
+	io_hdr.cmd_len = sizeof(cmd);
+	io_hdr.mx_sb_len = sizeof(sense_b);
+	io_hdr.dxfer_direction = SG_DXFER_FROM_DEV;
+	io_hdr.dxfer_len = len;
+	io_hdr.dxferp = buffer;
+	io_hdr.cmdp = cmd;
+	io_hdr.sbp = sense_b;
+	io_hdr.timeout = sg_timeout;
+	if (ioctl(fd, SG_IO, &io_hdr) < 0)
+		return -1;
+
+	if (sg_io_ok(io_hdr))
+		return 0;
+	return -1;
+}
+
+int bldev_inquire_pages(int fd, int page, char **buffer)
+{
+	int status = 0;
+	char *tmp;
+	int len;
+
+	*buffer = calloc(DEF_ALLOC_LEN, sizeof(char));
+	if (!*buffer) {
+		BL_LOG_ERR("%s: Out of memory!\n", __func__);
+		return -ENOMEM;
+	}
+
+	status = bldev_inquire_page(fd, page, *buffer, DEF_ALLOC_LEN);
+	if (status)
+		goto out;
+
+	status = -1;
+	if ((*(*buffer + 1) & 0xff) != page)
+		goto out;
+
+	len = (*(*buffer + 2) << 8) + *(*buffer + 3) + 4;
+	if (len > MX_ALLOC_LEN) {
+		BL_LOG_ERR("SCSI response length too long: %d\n", len);
+		goto out;
+	}
+	if (len > DEF_ALLOC_LEN) {
+		tmp = realloc(*buffer, len);
+		if (!tmp) {
+			BL_LOG_ERR("%s: Out of memory!\n", __func__);
+			status = -ENOMEM;
+			goto out;
+		}
+		*buffer = tmp;
+		status = bldev_inquire_page(fd, page, *buffer, len);
+		if (status)
+			goto out;
+	}
+	status = 0;
+ out:
+	return status;
+}
+
+/* For EMC multipath devices, use VPD page (0xc0) to get status.
+ * For other devices, return ACTIVE for now
+ */
+void bldev_read_ap_state(int fd, enum bl_path_state_e *ap_state_out)
+{
+	int status = 0;
+	char *buffer;
+
+	*ap_state_out = BL_PATH_STATE_ACTIVE;
+
+	status = bldev_inquire_pages(fd, 0xc0, &buffer);
+	if (status)
+		goto out;
+
+	if (buffer[4] < 0x02)
+		*ap_state_out = BL_PATH_STATE_PASSIVE;
+ out:
+	if (buffer)
+		free(buffer);
+	return;
+}
+
+struct bl_serial *bldev_read_serial(int fd, const char *filename)
+{
+	struct bl_serial *serial_out = NULL;
+	int status = 0, pos, len;
+	char *buffer;
+	struct bl_dev_id *dev_root, *dev_id;
+	unsigned int current_id = 0;
+
+	status = bldev_inquire_pages(fd, 0x83, &buffer);
+	if (status)
+		goto out;
+
+	dev_root = (struct bl_dev_id *)buffer;
+
+	pos = 0;
+	current_id = 0;
+	len = dev_root->len;
+	while (pos < (len - sizeof(struct bl_dev_id) + sizeof(unsigned char))) {
+		dev_id = (struct bl_dev_id *)&(dev_root->data[pos]);
+		if ((dev_id->ids & 0xf) < current_id)
+			continue;
+		switch (dev_id->ids & 0xf) {
+			/* We process SCSI ID with four ID cases: 0, 1, 2 and 3.
+			 * When more than one ID is available, priority is
+			 * 3>2>1>0.
+			 */
+		case 2:	/* EUI-64 based */
+			if ((dev_id->len != 8) && (dev_id->len != 12) &&
+			    (dev_id->len != 16)) {
+				BL_LOG_ERR("EUI-64 only decodes 8, "
+					   "12 and 16\n");
+				break;
+			}
+		case 3:	/* NAA */
+			/* TODO: NAA validity judgement too complicated,
+			 * so just ingore it here.
+			 */
+			if ((dev_id->type & 0xf) != 1) {
+				BL_LOG_ERR("Binary code_set expected\n");
+				break;
+			}
+		case 0:	/* vendor specific */
+		case 1:	/* T10 vendor identification */
+			current_id = dev_id->ids & 0xf;
+			if (serial_out)
+				bl_free_scsi_string(serial_out);
+			serial_out = bl_create_scsi_string(dev_id->len,
+							   dev_id->data);
+			break;
+		default:
+			break;
+		}
+		if (current_id == 3)
+			break;
+		pos += (dev_id->len + sizeof(struct bl_dev_id) -
+			sizeof(unsigned char));
+	}
+ out:
+	if (!serial_out)
+		serial_out = bl_create_scsi_string(strlen(filename), filename);
+	if (buffer)
+		free(buffer);
+	return serial_out;
+}
diff --git a/utils/blkmapd/device-process.c b/utils/blkmapd/device-process.c
new file mode 100644
index 0000000..9e91840
--- /dev/null
+++ b/utils/blkmapd/device-process.c
@@ -0,0 +1,394 @@
+/*
+ * device-process.c: detailed processing of device information sent
+ * from kernel.
+ *
+ * Copyright (c) 2006 The Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ *  Andy Adamson <andros@citi.umich.edu>
+ *  Fred Isaman <iisaman@umich.edu>
+ *
+ * Copyright (c) 2010 EMC Corporation, Haiying Tang <Tang_Haiying@emc.com>
+ *
+ * Used codes in linux/fs/nfs/blocklayout/blocklayoutdev.c.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <libdevmapper.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/user.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <arpa/inet.h>
+#include <linux/kdev_t.h>
+#include "device-discovery.h"
+
+uint32_t *blk_overflow(uint32_t * p, uint32_t * end, size_t nbytes)
+{
+	uint32_t *q = p + ((nbytes + 3) >> 2);
+	if (q > end || q < p)
+		return NULL;
+	return p;
+}
+
+static int decode_blk_signature(uint32_t **pp, uint32_t *end,
+				struct bl_sig *sig)
+{
+	int i, tmp;
+	uint32_t *p = *pp;
+
+	BLK_READBUF(p, end, 4);
+	READ32(sig->si_num_comps);
+	if (sig->si_num_comps == 0) {
+		BL_LOG_ERR("0 components in sig\n");
+		goto out_err;
+	}
+	if (sig->si_num_comps >= BLOCK_MAX_SIG_COMP) {
+		BL_LOG_ERR("number of sig comps %i >= BLOCK_MAX_SIG_COMP\n",
+			   sig->si_num_comps);
+		goto out_err;
+	}
+	for (i = 0; i < sig->si_num_comps; i++) {
+		BLK_READBUF(p, end, 12);
+		READ64(sig->si_comps[i].bs_offset);
+		READ32(tmp);
+		sig->si_comps[i].bs_length = tmp;
+		BLK_READBUF(p, end, tmp);
+		/* Note we rely here on fact that sig is used immediately
+		 * for mapping, then thrown away.
+		 */
+		sig->si_comps[i].bs_string = (char *)p;
+		BL_LOG_ERR("%s: si_comps[%d]: bs_length %d, bs_string %s\n",
+			   __func__, i, sig->si_comps[i].bs_length,
+			   sig->si_comps[i].bs_string);
+		p += ((tmp + 3) >> 2);
+	}
+	*pp = p;
+	return 0;
+ out_err:
+	return -EIO;
+}
+
+/* Read signature from device
+ * return 0: read successfully
+ * return -1: error
+ */
+int
+read_cmp_blk_sig(const char *dev_name, struct bl_sig_comp *comp,
+		 int64_t bs_offset)
+{
+	int fd, ret = -1;
+	char *sig = NULL;
+
+	fd = open(dev_name, O_RDONLY | O_LARGEFILE);
+	if (fd < 0) {
+		BL_LOG_ERR("%s could not be opened for read\n", dev_name);
+		goto error;
+	}
+
+	sig = (char *)malloc(comp->bs_length);
+	if (!sig) {
+		BL_LOG_ERR("%s: Out of memory\n", __func__);
+		goto error;
+	}
+
+	if (lseek64(fd, bs_offset, SEEK_SET) == -1) {
+		BL_LOG_ERR("File %s lseek error\n", dev_name);
+		goto error;
+	}
+
+	if (atomicio(read, fd, sig, comp->bs_length) != comp->bs_length) {
+		BL_LOG_ERR("File %s read error\n", dev_name);
+		goto error;
+	}
+
+	BL_LOG_ERR
+	    ("%s: %s sig: %s, bs_string: %s, bs_length: %d, bs_offset: %lld\n",
+	     __func__, dev_name, sig, comp->bs_string, comp->bs_length,
+	     (long long)bs_offset);
+	ret = memcmp(sig, comp->bs_string, comp->bs_length);
+
+ error:
+	if (sig)
+		free(sig);
+	if (fd >= 0)
+		close(fd);
+	return ret;
+}
+
+/*
+ * All signatures in sig must be found on disk for verification.
+ * Returns True if sig matches, False otherwise.
+ */
+static int verify_sig(struct bl_disk *disk, struct bl_sig *sig)
+{
+	struct bl_sig_comp *comp;
+	int i, ret;
+	int64_t bs_offset;
+
+	for (i = 0; i < sig->si_num_comps; i++) {
+		comp = &sig->si_comps[i];
+		bs_offset = comp->bs_offset;
+		if (bs_offset < 0)
+			bs_offset += (((int64_t) disk->size) << 9);
+		BL_LOG_ERR("%s: bs_offset: %lld\n",
+			   __func__, (long long) bs_offset);
+		ret = read_cmp_blk_sig(disk->valid_path->full_path,
+				       comp, bs_offset);
+		if (ret)
+			return 0;
+	}
+	return 1;
+}
+
+/*
+ * map_sig_to_device()
+ * Given a signature, walk the list of visible disks searching for
+ * a match. Returns True if mapping was done, False otherwise.
+ *
+ * While we're at it, fill in the vol->bv_size.
+ */
+static int map_sig_to_device(struct bl_sig *sig, struct bl_volume *vol)
+{
+	int mapped = 0;
+	struct bl_disk *disk = visible_disk_list;
+	char *filepath = 0;
+	struct bl_disk *lolDisk = disk;
+
+	while (lolDisk) {
+		BL_LOG_ERR("%s: visible_disk_list: %s\n", __func__,
+			   lolDisk->valid_path->full_path);
+		lolDisk = lolDisk->next;
+	}
+
+	/* scan disk list to find out match device */
+	while (disk) {
+		/* FIXME: should we use better algorithm for disk scan? */
+		mapped = verify_sig(disk, sig);
+		if (mapped) {
+			vol->param.bv_dev = disk->dev;
+			filepath = disk->valid_path->full_path;
+			vol->bv_size = disk->size;
+			break;
+		}
+		disk = disk->next;
+	}
+	return mapped;
+}
+
+/* We are given an array of XDR encoded array indices, each of which should
+ * refer to a previously decoded device.  Translate into a list of pointers
+ * to the appropriate pnfs_blk_volume's.
+ */
+static int set_vol_array(uint32_t **pp, uint32_t *end,
+			 struct bl_volume *vols, int working)
+{
+	int i, index;
+	uint32_t *p = *pp;
+	struct bl_volume **array = vols[working].bv_vols;
+	for (i = 0; i < vols[working].bv_vol_n; i++) {
+		BLK_READBUF(p, end, 4);
+		READ32(index);
+		if ((index < 0) || (index >= working)) {
+			BL_LOG_ERR("set_vol_array: Id %i out of range\n",
+				   index);
+			goto out_err;
+		}
+		array[i] = &vols[index];
+	}
+	*pp = p;
+	return 0;
+ out_err:
+	return -EIO;
+}
+
+static uint64_t sum_subvolume_sizes(struct bl_volume *vol)
+{
+	int i;
+	uint64_t sum = 0;
+	for (i = 0; i < vol->bv_vol_n; i++)
+		sum += vol->bv_vols[i]->bv_size;
+	return sum;
+}
+
+static int decode_blk_volume(uint32_t **pp, uint32_t *end,
+			     struct bl_volume *vols, int i, int *array_cnt)
+{
+	int status = 0, j;
+	struct bl_sig sig;
+	uint32_t *p = *pp;
+	struct bl_volume *vol = &vols[i];
+	uint64_t tmp, tmp_size;
+	div_t d;
+
+	BLK_READBUF(p, end, 4);
+	READ32(vol->bv_type);
+	switch (vol->bv_type) {
+	case BLOCK_VOLUME_SIMPLE:
+		*array_cnt = 0;
+		status = decode_blk_signature(&p, end, &sig);
+		if (status)
+			return status;
+		status = map_sig_to_device(&sig, vol);
+		if (!status) {
+			BL_LOG_ERR("Could not find disk for device\n");
+			return -ENXIO;
+		}
+		status = 0;
+		break;
+	case BLOCK_VOLUME_SLICE:
+		BLK_READBUF(p, end, 16);
+		READ_SECTOR(vol->param.bv_offset);
+		READ_SECTOR(vol->bv_size);
+		*array_cnt = vol->bv_vol_n = 1;
+		status = set_vol_array(&p, end, vols, i);
+		break;
+	case BLOCK_VOLUME_STRIPE:
+		BLK_READBUF(p, end, 8);
+		READ_SECTOR(vol->param.bv_stripe_unit);
+		off_t chunksize = vol->param.bv_stripe_unit;
+		if ((chunksize == 0) ||
+		    ((chunksize & (chunksize - 1)) != 0) ||
+		    (chunksize < (PAGE_SIZE >> 9)))
+			return -EIO;
+		BLK_READBUF(p, end, 4);
+		READ32(vol->bv_vol_n);
+		if (!vol->bv_vol_n)
+			return -EIO;
+		*array_cnt = vol->bv_vol_n;
+		status = set_vol_array(&p, end, vols, i);
+		if (status)
+			return status;
+		for (j = 1; j < vol->bv_vol_n; j++) {
+			if (vol->bv_vols[j]->bv_size !=
+			    vol->bv_vols[0]->bv_size) {
+				BL_LOG_ERR("varying subvol size\n");
+				return -EIO;
+			}
+		}
+		/* Make sure total size only includes addressable areas */
+		tmp_size = vol->bv_vols[0]->bv_size;
+		d = div(tmp_size, (uint32_t) vol->param.bv_stripe_unit);
+		tmp_size = d.quot;
+		vol->bv_size = tmp_size * vol->param.bv_stripe_unit;
+		break;
+	case BLOCK_VOLUME_CONCAT:
+		BLK_READBUF(p, end, 4);
+		READ32(vol->bv_vol_n);
+		if (!vol->bv_vol_n)
+			return -EIO;
+		*array_cnt = vol->bv_vol_n;
+		status = set_vol_array(&p, end, vols, i);
+		if (status)
+			return status;
+		vol->bv_size = sum_subvolume_sizes(vol);
+		break;
+	default:
+		BL_LOG_ERR("Unknown volume type %i\n", vol->bv_type);
+ out_err:
+		return -EIO;
+	}
+	*pp = p;
+	return status;
+}
+
+uint64_t process_deviceinfo(const char *dev_addr_buf,
+			    unsigned int dev_addr_len,
+			    uint32_t *major, uint32_t *minor)
+{
+	int num_vols, i, status, count;
+	uint32_t *p, *end;
+	struct bl_volume *vols = NULL, **arrays = NULL, **arrays_ptr = NULL;
+	uint64_t dev = 0;
+	int tried = 0;
+
+ restart:
+	p = (uint32_t *) dev_addr_buf;
+	end = (uint32_t *) ((char *)p + dev_addr_len);
+	/* Decode block volume */
+	BLK_READBUF(p, end, 4);
+	READ32(num_vols);
+	if (num_vols <= 0) {
+		BL_LOG_WARNING("Error: number of vols: %d\n", num_vols);
+		goto out_err;
+	}
+
+	vols = (struct bl_volume *)malloc(num_vols * sizeof(struct bl_volume));
+	if (!vols) {
+		BL_LOG_ERR("%s: Out of memory\n", __func__);
+		goto out_err;
+	}
+
+	/* Each volume in vols array needs its own array.  Save time by
+	 * allocating them all in one large hunk.  Because each volume
+	 * array can only reference previous volumes, and because once
+	 * a concat or stripe references a volume, it may never be
+	 * referenced again, the volume arrays are guaranteed to fit
+	 * in the suprisingly small space allocated.
+	 */
+	arrays =
+	    (struct bl_volume **)malloc(num_vols * 2 *
+					sizeof(struct bl_volume *));
+	if (!arrays) {
+		BL_LOG_ERR("%s: Out of memory\n", __func__);
+		goto out_err;
+	}
+
+	arrays_ptr = arrays;
+
+	for (i = 0; i < num_vols; i++) {
+		vols[i].bv_vols = arrays_ptr;
+		status = decode_blk_volume(&p, end, vols, i, &count);
+		if (status == -ENXIO && (tried <= 5)) {
+			sleep(1);
+			BL_LOG_DEBUG("%s: discover again!\n", __func__);
+			bl_discover_devices();
+			tried++;
+			free(vols);
+			free(arrays);
+			goto restart;
+		}
+		if (status)
+			goto out_err;
+		arrays_ptr += count;
+	}
+
+	if (p != end) {
+		BL_LOG_ERR("p is not equal to end!\n");
+		goto out_err;
+	}
+
+	dev = dm_device_create(vols, num_vols);
+	*major = MAJOR(dev);
+	*minor = MINOR(dev);
+ out_err:
+	if (vols)
+		free(vols);
+	if (arrays)
+		free(arrays);
+	return dev;
+}
diff --git a/utils/blkmapd/dm-device.c b/utils/blkmapd/dm-device.c
new file mode 100644
index 0000000..8162706
--- /dev/null
+++ b/utils/blkmapd/dm-device.c
@@ -0,0 +1,509 @@
+/*
+ * dm-device.c: create or remove device via device mapper API.
+ *
+ * Copyright (c) 2010 EMC Corporation, Haiying Tang <Tang_Haiying@emc.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <libdevmapper.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <linux/kdev_t.h>
+#include "device-discovery.h"
+
+#define DM_DEV_NAME_LEN		256
+
+#ifndef DM_MAX_TYPE_NAME
+#define DM_MAX_TYPE_NAME	16
+#endif
+
+#define DM_PARAMS_LEN		512	/* XXX: is this enough for target? */
+#define DM_DIR			"/dev/mapper"
+#define DM_DIR_LEN12
+#define TYPE_HAS_DEV(type)	((type == BLOCK_VOLUME_SIMPLE) || \
+			 (type == BLOCK_VOLUME_PSEUDO))
+
+struct bl_dm_table {
+	uint64_t offset;
+	uint64_t size;
+	char target_type[DM_MAX_TYPE_NAME];
+	char params[DM_PARAMS_LEN];
+	struct bl_dm_table *next;
+};
+
+struct bl_dm_tree {
+	uint64_t dev;
+	struct dm_tree *tree;
+	struct bl_dm_tree *next;
+};
+
+static inline struct bl_dm_table *bl_dm_table_alloc(void)
+{
+	return (struct bl_dm_table *)calloc(1, sizeof(struct bl_dm_table));
+}
+
+void bl_dm_table_free(struct bl_dm_table *bl_table_head)
+{
+	struct bl_dm_table *p = bl_table_head;
+	while (bl_table_head) {
+		p = bl_table_head->next;
+		free(bl_table_head);
+		bl_table_head = p;
+	}
+}
+
+void add_to_bl_dm_table(struct bl_dm_table **bl_table_head,
+			struct bl_dm_table *table)
+{
+	struct bl_dm_table *pre;
+	if (!*bl_table_head) {
+		*bl_table_head = table;
+		return;
+	}
+	pre = *bl_table_head;
+	while (pre->next)
+		pre = pre->next;
+	pre->next = table;
+	return;
+}
+
+struct bl_dm_tree *bl_tree_head;
+
+struct bl_dm_tree *find_bl_dm_tree(uint64_t dev)
+{
+	struct bl_dm_tree *p = bl_tree_head;
+	while (p) {
+		if (p->dev == dev)
+			return p;
+		p = p->next;
+	}
+	return NULL;
+}
+
+void del_from_bl_dm_tree(uint64_t dev)
+{
+	struct bl_dm_tree *pre = bl_tree_head;
+	struct bl_dm_tree *p;
+
+	p = pre;
+	while (p) {
+		if (p->dev == dev) {
+			pre->next = p->next;
+			if (p == bl_tree_head)
+				bl_tree_head = bl_tree_head->next;
+			free(p);
+			break;
+		}
+		pre = p;
+		p = pre->next;
+	}
+}
+
+void add_to_bl_dm_tree(struct bl_dm_tree *tree)
+{
+	struct bl_dm_tree *pre;
+	if (!bl_tree_head) {
+		bl_tree_head = tree;
+		return;
+	}
+	pre = bl_tree_head;
+	while (pre->next)
+		pre = pre->next;
+	pre->next = tree;
+	return;
+}
+
+/* Create device via device mapper
+ * return 0 when creation failed
+ * return dev no for created device
+ */
+uint64_t dm_single_device_create(const char *dev_name, struct bl_dm_table * p)
+{
+	struct dm_task *dmt;
+	struct dm_info dminfo;
+	int ret = 0;
+
+	dmt = dm_task_create(DM_DEVICE_CREATE);
+	if (!dmt) {
+		BL_LOG_ERR("Create dm_task for %s failed\n", dev_name);
+		return 0;
+	}
+	ret = dm_task_set_name(dmt, dev_name);
+	if (!ret)
+		goto err_out;
+
+	while (p) {
+		ret = dm_task_add_target(dmt, p->offset, p->size,
+					 p->target_type, p->params);
+		if (!ret)
+			goto err_out;
+		p = p->next;
+	}
+
+	ret = dm_task_run(dmt) &&
+	    dm_task_get_info(dmt, &dminfo) && dminfo.exists;
+
+	if (!ret)
+		goto err_out;
+
+	dm_task_update_nodes();
+
+ err_out:
+	dm_task_destroy(dmt);
+
+	if (!ret) {
+		BL_LOG_ERR("Create device %s failed\n", dev_name);
+		return 0;
+	}
+	return MKDEV(dminfo.major, dminfo.minor);
+}
+
+int dm_device_remove_byname(const char *dev_name)
+{
+	struct dm_task *dmt;
+	int ret = 0;
+
+	dmt = dm_task_create(DM_DEVICE_REMOVE);
+	if (!dmt)
+		return -ENODEV;
+
+	ret = dm_task_set_name(dmt, dev_name) && dm_task_run(dmt);
+
+	dm_task_update_nodes();
+
+	if (dmt)
+		dm_task_destroy(dmt);
+
+	return ret;
+}
+
+int dm_device_remove(uint64_t dev)
+{
+	struct dm_task *dmt;
+	struct dm_names *dmnames;
+	char *names = NULL;
+	int ret = -1;
+
+	/* Look for dev_name via dev, if dev_name could be transferred here,
+	   we could jump to DM_DEVICE_REMOVE directly */
+	dmt = dm_task_create(DM_DEVICE_LIST);
+	if (!dmt) {
+		BL_LOG_ERR("dm_task creation failed\n");
+		return -ENODEV;
+	}
+
+	ret = dm_task_run(dmt);
+	if (!ret) {
+		BL_LOG_ERR("dm_task_run failed\n");
+		goto error;
+	}
+
+	dmnames = dm_task_get_names(dmt);
+	if (!dmnames || !dmnames->dev) {
+		BL_LOG_ERR("dm_task_get_names failed\n");
+		goto error;
+	}
+
+	do {
+		if (dmnames->dev == dev) {
+			names = dmnames->name;
+			break;
+		}
+		dmnames = (void *)dmnames + dmnames->next;
+	} while (dmnames);
+
+	if (!names) {
+		BL_LOG_ERR("Could not find device\n");
+		goto error;
+	}
+
+	dm_task_update_nodes();
+
+ error:
+	dm_task_destroy(dmt);
+
+	/* Start to remove device */
+	if (names)
+		ret = dm_device_remove_byname(names);
+	return ret;
+}
+
+static unsigned long dev_count;
+
+void dm_devicelist_remove(unsigned long start, unsigned long end)
+{
+	char dev_name[DM_DEV_NAME_LEN];
+	unsigned long count;
+
+	if ((start >= dev_count) || (end <= 1) || (start >= end - 1))
+		return;
+
+	for (count = end - 1; count > start; count--) {
+		sprintf(dev_name, "pnfs_vol_%lu", count - 1);
+		dm_device_remove_byname(dev_name);
+	}
+
+	return;
+}
+
+void bl_dm_remove_tree(uint64_t dev)
+{
+	struct bl_dm_tree *p;
+
+	p = find_bl_dm_tree(dev);
+	if (!p)
+		return;
+
+	dm_tree_free(p->tree);
+	del_from_bl_dm_tree(dev);
+}
+
+void bl_dm_create_tree(uint64_t dev)
+{
+	struct dm_tree *tree;
+	struct bl_dm_tree *bl_tree;
+
+	bl_tree = find_bl_dm_tree(dev);
+	if (bl_tree)
+		return;		/* XXX: error? */
+
+	tree = dm_tree_create();
+	if (!tree)
+		return;
+
+	if (!dm_tree_add_dev(tree, MAJOR(dev), MINOR(dev))) {
+		dm_tree_free(tree);
+		return;
+	}
+
+	bl_tree = malloc(sizeof(struct bl_dm_tree));
+	if (!bl_tree) {
+		dm_tree_free(tree);
+		return;
+	}
+
+	bl_tree->dev = dev;
+	bl_tree->tree = tree;
+	bl_tree->next = NULL;
+	add_to_bl_dm_tree(bl_tree);
+
+	return;
+}
+
+uint64_t dm_device_nametodev(char *dev_name)
+{
+	struct dm_task *dmt;
+	int ret = 0;
+	struct dm_info dminfo;
+
+	dmt = dm_task_create(DM_DEVICE_INFO);
+	if (!dmt)
+		return -ENODEV;
+
+	ret = dm_task_set_name(dmt, dev_name) &&
+	    dm_task_run(dmt) && dm_task_get_info(dmt, &dminfo);
+
+	if (dmt)
+		dm_task_destroy(dmt);
+
+	if (!ret)
+		return 0;
+
+	return MKDEV(dminfo.major, dminfo.minor);
+}
+
+int dm_device_remove_all(uint64_t *dev)
+{
+	struct bl_dm_tree *p;
+	struct dm_tree_node *node;
+	const char *uuid;
+	int ret = 0;
+	uint32_t major, minor;
+	uint64_t bl_dev;
+
+	memcpy(&major, dev, sizeof(uint32_t));
+	memcpy(&minor, (void *)dev + sizeof(uint32_t), sizeof(uint32_t));
+	bl_dev = MKDEV(major, minor);
+	p = find_bl_dm_tree(bl_dev);
+	if (!p)
+		return ret;
+
+	node = dm_tree_find_node(p->tree, MAJOR(bl_dev), MINOR(bl_dev));
+	if (!node)
+		return ret;
+
+	uuid = dm_tree_node_get_uuid(node);
+	if (!uuid)
+		return ret;
+
+	dm_device_remove(bl_dev);
+	ret = dm_tree_deactivate_children(node, uuid, strlen(uuid));
+	dm_task_update_nodes();
+	bl_dm_remove_tree(bl_dev);
+	return ret;
+}
+
+/* TODO: check the value for DM_DEV_NAME_LEN, DM_TYPE_LEN, DM_PARAMS_LEN */
+uint64_t dm_device_create(struct bl_volume *vols, int num_vols)
+{
+	uint64_t size, dev = 0;
+	unsigned long count = dev_count;
+	int number = 0, i, pos;
+	struct bl_volume *node;
+	char *tmp;
+	struct bl_dm_table *table = NULL;
+	struct bl_dm_table *bl_table_head = NULL;
+	unsigned int len;
+	char *dev_name = NULL;
+	/* Create pseudo device here */
+	while (number < num_vols) {
+		node = &vols[number];
+		switch (node->bv_type) {
+		case BLOCK_VOLUME_SIMPLE:
+			/* Do not need to create device here */
+			dev = node->param.bv_dev;
+			goto continued;
+		case BLOCK_VOLUME_SLICE:
+			table = bl_dm_table_alloc();
+			if (!table)
+				goto out;
+			table->offset = 0;
+			table->size = node->bv_size;
+			strcpy(table->target_type, "linear");
+			if (!TYPE_HAS_DEV(node->bv_vols[0]->bv_type)) {
+				free(table);
+				goto out;
+			}
+			dev = node->bv_vols[0]->param.bv_dev;
+			tmp = table->params;
+			if (!dm_format_dev(tmp, DM_PARAMS_LEN,
+					   MAJOR(dev), MINOR(dev))) {
+				free(table);
+				goto out;
+			}
+			tmp += strlen(tmp);
+			sprintf(tmp, " %lu", node->param.bv_offset);
+			add_to_bl_dm_table(&bl_table_head, table);
+			break;
+		case BLOCK_VOLUME_STRIPE:
+			table = bl_dm_table_alloc();
+			if (!table)
+				goto out;
+			table->offset = 0;
+			table->size = node->bv_size;
+			strcpy(table->target_type, "striped");
+			sprintf(table->params, "%d %lu %n", node->bv_vol_n,
+				node->param.bv_stripe_unit, &pos);
+			/* Repeatedly copy subdev to params */
+			tmp = table->params + pos;
+			len = DM_PARAMS_LEN - pos;
+			for (i = 0; i < node->bv_vol_n; i++) {
+				if (!TYPE_HAS_DEV(node->bv_vols[i]->bv_type)) {
+					free(table);
+					goto out;
+				}
+				dev = node->bv_vols[i]->param.bv_dev;
+				if (!dm_format_dev(tmp, len, MAJOR(dev),
+						   MINOR(dev))) {
+					free(table);
+					goto out;
+				}
+				pos = strlen(tmp);
+				tmp += pos;
+				len -= pos;
+				sprintf(tmp, " %d ", 0);
+				tmp += 3;
+				len -= 3;
+			}
+			add_to_bl_dm_table(&bl_table_head, table);
+			break;
+		case BLOCK_VOLUME_CONCAT:
+			size = 0;
+			for (i = 0; i < node->bv_vol_n; i++) {
+				table = bl_dm_table_alloc();
+				if (!table)
+					goto out;
+				table->offset = size;
+				table->size = node->bv_vols[i]->bv_size;
+				if (!TYPE_HAS_DEV(node->bv_vols[i]->bv_type)) {
+					free(table);
+					goto out;
+				}
+				strcpy(table->target_type, "linear");
+				tmp = table->params;
+				dev = node->bv_vols[i]->param.bv_dev;
+				if (!dm_format_dev(tmp, DM_PARAMS_LEN,
+						   MAJOR(dev), MINOR(dev))) {
+					free(table);
+					goto out;
+				}
+				tmp += strlen(tmp);
+				sprintf(tmp, " %d", 0);
+				size += table->size;
+				add_to_bl_dm_table(&bl_table_head, table);
+			}
+			break;
+		default:
+			/* Delete previous temporary devices */
+			dm_devicelist_remove(count, dev_count);
+			goto out;
+		}		/* end of swtich */
+		/* Create dev_name here. Name of device is pnfs_vol_XXX */
+		if (dev_name)
+			free(dev_name);
+		dev_name = (char *)calloc(DM_DEV_NAME_LEN, sizeof(char));
+		if (!dev_name) {
+			BL_LOG_ERR("%s: Out of memory\n", __func__);
+			goto out;
+		}
+		sprintf(dev_name, "pnfs_vol_%lu", dev_count++);
+
+		dev = dm_single_device_create(dev_name, bl_table_head);
+		if (!dev) {
+			/* Delete previous temporary devices */
+			dm_devicelist_remove(count, dev_count);
+			goto out;
+		}
+		node->param.bv_dev = dev;
+		/* TODO: extend use with PSEUDO later */
+		node->bv_type = BLOCK_VOLUME_PSEUDO;
+ continued:
+		number++;
+		if (bl_table_head)
+			bl_dm_table_free(bl_table_head);
+		bl_table_head = NULL;
+	}
+ out:
+	if (bl_table_head)
+		bl_dm_table_free(bl_table_head);
+	bl_table_head = NULL;
+	if (dev)
+		bl_dm_create_tree(dev);
+	if (dev_name)
+		free(dev_name);
+	return dev;
+}
diff --git a/utils/blkmapd/etc/blkmapd.conf b/utils/blkmapd/etc/blkmapd.conf
new file mode 100644
index 0000000..da70d94
--- /dev/null
+++ b/utils/blkmapd/etc/blkmapd.conf
@@ -0,0 +1,10 @@
+# This is an example config file
+
+# Look at all /dev/sd* devices
+# /dev/sd or /dev/sd*
+/dev/sd*
+
+# Look at all /dev/mapper/* devices
+# /dev/mapper/* or
+# /dev/mapper/
+/dev/mapper/*
diff --git a/utils/blkmapd/etc/initd/initd.redhat b/utils/blkmapd/etc/initd/initd.redhat
new file mode 100644
index 0000000..d6a77e8
--- /dev/null
+++ b/utils/blkmapd/etc/initd/initd.redhat
@@ -0,0 +1,76 @@
+#!/bin/sh
+#
+# description: Starts and stops the iSCSI initiator
+#
+# processname: blkmapd
+# pidfile: /var/run/blkmapd.pid
+# config:  /etc/blkmapd.conf
+
+# Source function library.
+if [ -f /etc/init.d/functions ] ; then
+	. /etc/init.d/functions
+elif [ -f /etc/rc.d/init.d/functions ] ; then
+	. /etc/rc.d/init.d/functions
+else
+	exit 0
+fi
+
+PATH=/sbin:/bin:/usr/sbin:/usr/bin
+
+RETVAL=0
+
+start()
+{
+	echo -n $"Starting pNFS block-layout device discovery service: "
+	modprobe -q blocklayoutdriver
+	daemon /usr/sbin/blkmapd
+	RETVAL=$?
+	if [ $RETVAL -eq 0 ]; then
+		touch /var/lock/subsys/blkmapd
+	fi
+	echo
+	return $RETVAL
+}
+
+stop()
+{
+	echo -n $"Stopping pNFS block-layout device discovery service: "
+	killproc blkmapd 2> /dev/null
+	rm -f /var/run/blkmapd.pid
+	RETVAL=$?
+	[ $RETVAL -eq 0 ] && rm -f /var/lock/subsys/blkmapd
+	if [ $RETVAL -eq 0 ]; then
+                echo_success
+        else
+                echo_failure
+        fi
+	echo
+	return $RETVAL
+}
+
+restart()
+{
+	stop
+	start
+}
+
+case "$1" in
+	start)
+		start
+		;;
+	stop)
+		stop
+		;;
+	restart)
+		stop
+		start
+		;;
+	status)
+		status blkmapd
+		;;
+	*)
+	echo $"Usage: $0 {start|stop|restart|status}"
+	exit 1
+esac
+
+exit $RETVAL
-- 
1.7.0.4