Set delay_resume_if_new on deptree snapshot origin.

[lvm2.git] / libdm / libdm-deptree.c

/*
 * Copyright (C) 2005-2011 Red Hat, Inc. All rights reserved.
 *
 * This file is part of the device-mapper userspace tools.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU Lesser General Public License v.2.1.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "dmlib.h"
#include "libdm-targets.h"
#include "libdm-common.h"
#include "kdev_t.h"
#include "dm-ioctl.h"

#include <stdarg.h>
#include <sys/param.h>
#include <sys/utsname.h>

#define MAX_TARGET_PARAMSIZE 500000

#define REPLICATOR_LOCAL_SITE 0

/* Supported segment types */
enum {
        SEG_CRYPT,
        SEG_ERROR,
        SEG_LINEAR,
        SEG_MIRRORED,
        SEG_REPLICATOR,
        SEG_REPLICATOR_DEV,
        SEG_SNAPSHOT,
        SEG_SNAPSHOT_ORIGIN,
        SEG_SNAPSHOT_MERGE,
        SEG_STRIPED,
        SEG_ZERO,
        SEG_THIN_POOL,
        SEG_THIN,
        SEG_RAID1,
        SEG_RAID4,
        SEG_RAID5_LA,
        SEG_RAID5_RA,
        SEG_RAID5_LS,
        SEG_RAID5_RS,
        SEG_RAID6_ZR,
        SEG_RAID6_NR,
        SEG_RAID6_NC,
        SEG_LAST,
};

/* FIXME Add crypt and multipath support */

struct {
        unsigned type;
        const char *target;
} dm_segtypes[] = {
        { SEG_CRYPT, "crypt" },
        { SEG_ERROR, "error" },
        { SEG_LINEAR, "linear" },
        { SEG_MIRRORED, "mirror" },
        { SEG_REPLICATOR, "replicator" },
        { SEG_REPLICATOR_DEV, "replicator-dev" },
        { SEG_SNAPSHOT, "snapshot" },
        { SEG_SNAPSHOT_ORIGIN, "snapshot-origin" },
        { SEG_SNAPSHOT_MERGE, "snapshot-merge" },
        { SEG_STRIPED, "striped" },
        { SEG_ZERO, "zero"},
        { SEG_THIN_POOL, "thin-pool"},
        { SEG_THIN, "thin"},
        { SEG_RAID1, "raid1"},
        { SEG_RAID4, "raid4"},
        { SEG_RAID5_LA, "raid5_la"},
        { SEG_RAID5_RA, "raid5_ra"},
        { SEG_RAID5_LS, "raid5_ls"},
        { SEG_RAID5_RS, "raid5_rs"},
        { SEG_RAID6_ZR, "raid6_zr"},
        { SEG_RAID6_NR, "raid6_nr"},
        { SEG_RAID6_NC, "raid6_nc"},

        /*
         *WARNING: Since 'raid' target overloads this 1:1 mapping table
         * for search do not add new enum elements past them!
         */
        { SEG_RAID5_LS, "raid5"}, /* same as "raid5_ls" (default for MD also) */
        { SEG_RAID6_ZR, "raid6"}, /* same as "raid6_zr" */
        { SEG_LAST, NULL },
};

/* Some segment types have a list of areas of other devices attached */
struct seg_area {
        struct dm_list list;

        struct dm_tree_node *dev_node;

        uint64_t offset;

        unsigned rsite_index;           /* Replicator site index */
        struct dm_tree_node *slog;      /* Replicator sync log node */
        uint64_t region_size;           /* Replicator sync log size */
        uint32_t flags;                 /* Replicator sync log flags */
};

struct dm_thin_message {
        dm_thin_message_t type;
        union {
                struct {
                        uint32_t device_id;
                        uint32_t origin_id;
                } m_create_snap;
                struct {
                        uint32_t device_id;
                } m_create_thin;
                struct {
                        uint32_t device_id;
                } m_delete;
                struct {
                        uint64_t current_id;
                        uint64_t new_id;
                } m_set_transaction_id;
        } u;
};

struct thin_message {
        struct dm_list list;
        struct dm_thin_message message;
        int expected_errno;
};

/* Replicator-log has a list of sites */
/* FIXME: maybe move to seg_area too? */
struct replicator_site {
        struct dm_list list;

        unsigned rsite_index;
        dm_replicator_mode_t mode;
        uint32_t async_timeout;
        uint32_t fall_behind_ios;
        uint64_t fall_behind_data;
};

/* Per-segment properties */
struct load_segment {
        struct dm_list list;

        unsigned type;

        uint64_t size;

        unsigned area_count;            /* Linear + Striped + Mirrored + Crypt + Replicator */
        struct dm_list areas;           /* Linear + Striped + Mirrored + Crypt + Replicator */

        uint32_t stripe_size;           /* Striped + raid */

        int persistent;                 /* Snapshot */
        uint32_t chunk_size;            /* Snapshot */
        struct dm_tree_node *cow;       /* Snapshot */
        struct dm_tree_node *origin;    /* Snapshot + Snapshot origin */
        struct dm_tree_node *merge;     /* Snapshot */

        struct dm_tree_node *log;       /* Mirror + Replicator */
        uint32_t region_size;           /* Mirror + raid */
        unsigned clustered;             /* Mirror */
        unsigned mirror_area_count;     /* Mirror */
        uint32_t flags;                 /* Mirror log */
        char *uuid;                     /* Clustered mirror log */

        const char *cipher;             /* Crypt */
        const char *chainmode;          /* Crypt */
        const char *iv;                 /* Crypt */
        uint64_t iv_offset;             /* Crypt */
        const char *key;                /* Crypt */

        const char *rlog_type;          /* Replicator */
        struct dm_list rsites;          /* Replicator */
        unsigned rsite_count;           /* Replicator */
        unsigned rdevice_count;         /* Replicator */
        struct dm_tree_node *replicator;/* Replicator-dev */
        uint64_t rdevice_index;         /* Replicator-dev */

        uint64_t rebuilds;            /* raid */

        struct dm_tree_node *metadata;  /* Thin_pool */
        struct dm_tree_node *pool;      /* Thin_pool, Thin */
        struct dm_list thin_messages;   /* Thin_pool */
        uint64_t transaction_id;        /* Thin_pool */
        uint64_t low_water_mark;        /* Thin_pool */
        uint32_t data_block_size;       /* Thin_pool */
        unsigned skip_block_zeroing;    /* Thin_pool */
        uint32_t device_id;             /* Thin */

};

/* Per-device properties */
struct load_properties {
        int read_only;
        uint32_t major;
        uint32_t minor;

        uint32_t read_ahead;
        uint32_t read_ahead_flags;

        unsigned segment_count;
        unsigned size_changed;
        struct dm_list segs;

        const char *new_name;

        /* If immediate_dev_node is set to 1, try to create the dev node
         * as soon as possible (e.g. in preload stage even during traversal
         * and processing of dm tree). This will also flush all stacked dev
         * node operations, synchronizing with udev.
         */
        unsigned immediate_dev_node;

        /*
         * If the device size changed from zero and this is set,
         * don't resume the device immediately, even if the device
         * has parents.  This works provided the parents do not
         * validate the device size and is required by pvmove to
         * avoid starting the mirror resync operation too early.
         */
        unsigned delay_resume_if_new;

        /* Send messages for this node in preload */
        unsigned send_messages;
};

/* Two of these used to join two nodes with uses and used_by. */
struct dm_tree_link {
        struct dm_list list;
        struct dm_tree_node *node;
};

struct dm_tree_node {
        struct dm_tree *dtree;

        const char *name;
        const char *uuid;
        struct dm_info info;

        struct dm_list uses;            /* Nodes this node uses */
        struct dm_list used_by;         /* Nodes that use this node */

        int activation_priority;        /* 0 gets activated first */

        uint16_t udev_flags;            /* Udev control flags */

        void *context;                  /* External supplied context */

        struct load_properties props;   /* For creation/table (re)load */

        /*
         * If presuspend of child node is needed
         * Note: only direct child is allowed
         */
        struct dm_tree_node *presuspend_node;

        /* Callback */
        dm_node_callback_fn callback;
        void *callback_data;
};

struct dm_tree {
        struct dm_pool *mem;
        struct dm_hash_table *devs;
        struct dm_hash_table *uuids;
        struct dm_tree_node root;
        int skip_lockfs;                /* 1 skips lockfs (for non-snapshots) */
        int no_flush;                   /* 1 sets noflush (mirrors/multipath) */
        int retry_remove;               /* 1 retries remove if not successful */
        uint32_t cookie;
};

/*
 * Tree functions.
 */
struct dm_tree *dm_tree_create(void)
{
        struct dm_pool *dmem;
        struct dm_tree *dtree;

        if (!(dmem = dm_pool_create("dtree", 1024)) ||
            !(dtree = dm_pool_zalloc(dmem, sizeof(*dtree)))) {
                log_error("Failed to allocate dtree.");
                if (dmem)
                        dm_pool_destroy(dmem);
                return NULL;
        }

        dtree->root.dtree = dtree;
        dm_list_init(&dtree->root.uses);
        dm_list_init(&dtree->root.used_by);
        dtree->skip_lockfs = 0;
        dtree->no_flush = 0;
        dtree->mem = dmem;

        if (!(dtree->devs = dm_hash_create(8))) {
                log_error("dtree hash creation failed");
                dm_pool_destroy(dtree->mem);
                return NULL;
        }

        if (!(dtree->uuids = dm_hash_create(32))) {
                log_error("dtree uuid hash creation failed");
                dm_hash_destroy(dtree->devs);
                dm_pool_destroy(dtree->mem);
                return NULL;
        }

        return dtree;
}

void dm_tree_free(struct dm_tree *dtree)
{
        if (!dtree)
                return;

        dm_hash_destroy(dtree->uuids);
        dm_hash_destroy(dtree->devs);
        dm_pool_destroy(dtree->mem);
}

void dm_tree_set_cookie(struct dm_tree_node *node, uint32_t cookie)
{
        node->dtree->cookie = cookie;
}

uint32_t dm_tree_get_cookie(struct dm_tree_node *node)
{
        return node->dtree->cookie;
}

void dm_tree_skip_lockfs(struct dm_tree_node *dnode)
{
        dnode->dtree->skip_lockfs = 1;
}

void dm_tree_use_no_flush_suspend(struct dm_tree_node *dnode)
{
        dnode->dtree->no_flush = 1;
}

void dm_tree_retry_remove(struct dm_tree_node *dnode)
{
        dnode->dtree->retry_remove = 1;
}

/*
 * Node functions.
 */
static int _nodes_are_linked(const struct dm_tree_node *parent,
                             const struct dm_tree_node *child)
{
        struct dm_tree_link *dlink;

        dm_list_iterate_items(dlink, &parent->uses)
                if (dlink->node == child)
                        return 1;

        return 0;
}

static int _link(struct dm_list *list, struct dm_tree_node *node)
{
        struct dm_tree_link *dlink;

        if (!(dlink = dm_pool_alloc(node->dtree->mem, sizeof(*dlink)))) {
                log_error("dtree link allocation failed");
                return 0;
        }

        dlink->node = node;
        dm_list_add(list, &dlink->list);

        return 1;
}

static int _link_nodes(struct dm_tree_node *parent,
                       struct dm_tree_node *child)
{
        if (_nodes_are_linked(parent, child))
                return 1;

        if (!_link(&parent->uses, child))
                return 0;

        if (!_link(&child->used_by, parent))
                return 0;

        return 1;
}

static void _unlink(struct dm_list *list, struct dm_tree_node *node)
{
        struct dm_tree_link *dlink;

        dm_list_iterate_items(dlink, list)
                if (dlink->node == node) {
                        dm_list_del(&dlink->list);
                        break;
                }
}

static void _unlink_nodes(struct dm_tree_node *parent,
                          struct dm_tree_node *child)
{
        if (!_nodes_are_linked(parent, child))
                return;

        _unlink(&parent->uses, child);
        _unlink(&child->used_by, parent);
}

static int _add_to_toplevel(struct dm_tree_node *node)
{
        return _link_nodes(&node->dtree->root, node);
}

static void _remove_from_toplevel(struct dm_tree_node *node)
{
        _unlink_nodes(&node->dtree->root, node);
}

static int _add_to_bottomlevel(struct dm_tree_node *node)
{
        return _link_nodes(node, &node->dtree->root);
}

static void _remove_from_bottomlevel(struct dm_tree_node *node)
{
        _unlink_nodes(node, &node->dtree->root);
}

static int _link_tree_nodes(struct dm_tree_node *parent, struct dm_tree_node *child)
{
        /* Don't link to root node if child already has a parent */
        if (parent == &parent->dtree->root) {
                if (dm_tree_node_num_children(child, 1))
                        return 1;
        } else
                _remove_from_toplevel(child);

        if (child == &child->dtree->root) {
                if (dm_tree_node_num_children(parent, 0))
                        return 1;
        } else
                _remove_from_bottomlevel(parent);

        return _link_nodes(parent, child);
}

static struct dm_tree_node *_create_dm_tree_node(struct dm_tree *dtree,
                                                 const char *name,
                                                 const char *uuid,
                                                 struct dm_info *info,
                                                 void *context,
                                                 uint16_t udev_flags)
{
        struct dm_tree_node *node;
        uint64_t dev;

        if (!(node = dm_pool_zalloc(dtree->mem, sizeof(*node)))) {
                log_error("_create_dm_tree_node alloc failed");
                return NULL;
        }

        node->dtree = dtree;

        node->name = name;
        node->uuid = uuid;
        node->info = *info;
        node->context = context;
        node->udev_flags = udev_flags;
        node->activation_priority = 0;

        dm_list_init(&node->uses);
        dm_list_init(&node->used_by);
        dm_list_init(&node->props.segs);

        dev = MKDEV(info->major, info->minor);

        if (!dm_hash_insert_binary(dtree->devs, (const char *) &dev,
                                sizeof(dev), node)) {
                log_error("dtree node hash insertion failed");
                dm_pool_free(dtree->mem, node);
                return NULL;
        }

        if (uuid && *uuid &&
            !dm_hash_insert(dtree->uuids, uuid, node)) {
                log_error("dtree uuid hash insertion failed");
                dm_hash_remove_binary(dtree->devs, (const char *) &dev,
                                      sizeof(dev));
                dm_pool_free(dtree->mem, node);
                return NULL;
        }

        return node;
}

static struct dm_tree_node *_find_dm_tree_node(struct dm_tree *dtree,
                                               uint32_t major, uint32_t minor)
{
        uint64_t dev = MKDEV(major, minor);

        return dm_hash_lookup_binary(dtree->devs, (const char *) &dev,
                                  sizeof(dev));
}

static struct dm_tree_node *_find_dm_tree_node_by_uuid(struct dm_tree *dtree,
                                                       const char *uuid)
{
        struct dm_tree_node *node;
        const char *default_uuid_prefix;
        size_t default_uuid_prefix_len;

        if ((node = dm_hash_lookup(dtree->uuids, uuid)))
                return node;

        default_uuid_prefix = dm_uuid_prefix();
        default_uuid_prefix_len = strlen(default_uuid_prefix);

        if (strncmp(uuid, default_uuid_prefix, default_uuid_prefix_len))
                return NULL;

        return dm_hash_lookup(dtree->uuids, uuid + default_uuid_prefix_len);
}

void dm_tree_node_set_udev_flags(struct dm_tree_node *dnode, uint16_t udev_flags)

{
        struct dm_info *dinfo = &dnode->info;

        if (udev_flags != dnode->udev_flags)
                log_debug("Resetting %s (%" PRIu32 ":%" PRIu32
                          ") udev_flags from 0x%x to 0x%x",
                          dnode->name, dinfo->major, dinfo->minor,
                          dnode->udev_flags, udev_flags);
        dnode->udev_flags = udev_flags;
}

void dm_tree_node_set_read_ahead(struct dm_tree_node *dnode,
                                 uint32_t read_ahead,
                                 uint32_t read_ahead_flags)
{
        dnode->props.read_ahead = read_ahead;
        dnode->props.read_ahead_flags = read_ahead_flags;
}

void dm_tree_node_set_presuspend_node(struct dm_tree_node *node,
                                      struct dm_tree_node *presuspend_node)
{
        node->presuspend_node = presuspend_node;
}

const char *dm_tree_node_get_name(const struct dm_tree_node *node)
{
        return node->info.exists ? node->name : "";
}

const char *dm_tree_node_get_uuid(const struct dm_tree_node *node)
{
        return node->info.exists ? node->uuid : "";
}

const struct dm_info *dm_tree_node_get_info(const struct dm_tree_node *node)
{
        return &node->info;
}

void *dm_tree_node_get_context(const struct dm_tree_node *node)
{
        return node->context;
}

int dm_tree_node_size_changed(const struct dm_tree_node *dnode)
{
        return dnode->props.size_changed;
}

int dm_tree_node_num_children(const struct dm_tree_node *node, uint32_t inverted)
{
        if (inverted) {
                if (_nodes_are_linked(&node->dtree->root, node))
                        return 0;
                return dm_list_size(&node->used_by);
        }

        if (_nodes_are_linked(node, &node->dtree->root))
                return 0;

        return dm_list_size(&node->uses);
}

/*
 * Returns 1 if no prefix supplied
 */
static int _uuid_prefix_matches(const char *uuid, const char *uuid_prefix, size_t uuid_prefix_len)
{
        const char *default_uuid_prefix = dm_uuid_prefix();
        size_t default_uuid_prefix_len = strlen(default_uuid_prefix);

        if (!uuid_prefix)
                return 1;

        if (!strncmp(uuid, uuid_prefix, uuid_prefix_len))
                return 1;

        /* Handle transition: active device uuids might be missing the prefix */
        if (uuid_prefix_len <= 4)
                return 0;

        if (!strncmp(uuid, default_uuid_prefix, default_uuid_prefix_len))
                return 0;

        if (strncmp(uuid_prefix, default_uuid_prefix, default_uuid_prefix_len))
                return 0;

        if (!strncmp(uuid, uuid_prefix + default_uuid_prefix_len, uuid_prefix_len - default_uuid_prefix_len))
                return 1;

        return 0;
}

/*
 * Returns 1 if no children.
 */
static int _children_suspended(struct dm_tree_node *node,
                               uint32_t inverted,
                               const char *uuid_prefix,
                               size_t uuid_prefix_len)
{
        struct dm_list *list;
        struct dm_tree_link *dlink;
        const struct dm_info *dinfo;
        const char *uuid;

        if (inverted) {
                if (_nodes_are_linked(&node->dtree->root, node))
                        return 1;
                list = &node->used_by;
        } else {
                if (_nodes_are_linked(node, &node->dtree->root))
                        return 1;
                list = &node->uses;
        }

        dm_list_iterate_items(dlink, list) {
                if (!(uuid = dm_tree_node_get_uuid(dlink->node))) {
                        stack;
                        continue;
                }

                /* Ignore if it doesn't belong to this VG */
                if (!_uuid_prefix_matches(uuid, uuid_prefix, uuid_prefix_len))
                        continue;

                /* Ignore if parent node wants to presuspend this node */
                if (dlink->node->presuspend_node == node)
                        continue;

                if (!(dinfo = dm_tree_node_get_info(dlink->node))) {
                        stack;  /* FIXME Is this normal? */
                        return 0;
                }

                if (!dinfo->suspended)
                        return 0;
        }

        return 1;
}

/*
 * Set major and minor to zero for root of tree.
 */
struct dm_tree_node *dm_tree_find_node(struct dm_tree *dtree,
                                          uint32_t major,
                                          uint32_t minor)
{
        if (!major && !minor)
                return &dtree->root;

        return _find_dm_tree_node(dtree, major, minor);
}

/*
 * Set uuid to NULL for root of tree.
 */
struct dm_tree_node *dm_tree_find_node_by_uuid(struct dm_tree *dtree,
                                                  const char *uuid)
{
        if (!uuid || !*uuid)
                return &dtree->root;

        return _find_dm_tree_node_by_uuid(dtree, uuid);
}

/*
 * First time set *handle to NULL.
 * Set inverted to invert the tree.
 */
struct dm_tree_node *dm_tree_next_child(void **handle,
                                        const struct dm_tree_node *parent,
                                        uint32_t inverted)
{
        struct dm_list **dlink = (struct dm_list **) handle;
        const struct dm_list *use_list;

        if (inverted)
                use_list = &parent->used_by;
        else
                use_list = &parent->uses;

        if (!*dlink)
                *dlink = dm_list_first(use_list);
        else
                *dlink = dm_list_next(use_list, *dlink);

        return (*dlink) ? dm_list_item(*dlink, struct dm_tree_link)->node : NULL;
}

static int _deps(struct dm_task **dmt, struct dm_pool *mem, uint32_t major, uint32_t minor,
                 const char **name, const char **uuid, unsigned inactive_table,
                 struct dm_info *info, struct dm_deps **deps)
{
        memset(info, 0, sizeof(*info));

        if (!dm_is_dm_major(major)) {
                if (name)
                        *name = "";
                if (uuid)
                        *uuid = "";
                *deps = NULL;
                info->major = major;
                info->minor = minor;
                return 1;
        }

        if (!(*dmt = dm_task_create(DM_DEVICE_DEPS))) {
                log_error("deps dm_task creation failed");
                return 0;
        }

        if (!dm_task_set_major(*dmt, major)) {
                log_error("_deps: failed to set major for (%" PRIu32 ":%" PRIu32 ")",
                          major, minor);
                goto failed;
        }

        if (!dm_task_set_minor(*dmt, minor)) {
                log_error("_deps: failed to set minor for (%" PRIu32 ":%" PRIu32 ")",
                          major, minor);
                goto failed;
        }

        if (inactive_table && !dm_task_query_inactive_table(*dmt)) {
                log_error("_deps: failed to set inactive table for (%" PRIu32 ":%" PRIu32 ")",
                          major, minor);
                goto failed;
        }

        if (!dm_task_run(*dmt)) {
                log_error("_deps: task run failed for (%" PRIu32 ":%" PRIu32 ")",
                          major, minor);
                goto failed;
        }

        if (!dm_task_get_info(*dmt, info)) {
                log_error("_deps: failed to get info for (%" PRIu32 ":%" PRIu32 ")",
                          major, minor);
                goto failed;
        }

        if (!info->exists) {
                if (name)
                        *name = "";
                if (uuid)
                        *uuid = "";
                *deps = NULL;
        } else {
                if (info->major != major) {
                        log_error("Inconsistent dtree major number: %u != %u",
                                  major, info->major);
                        goto failed;
                }
                if (info->minor != minor) {
                        log_error("Inconsistent dtree minor number: %u != %u",
                                  minor, info->minor);
                        goto failed;
                }
                if (name && !(*name = dm_pool_strdup(mem, dm_task_get_name(*dmt)))) {
                        log_error("name pool_strdup failed");
                        goto failed;
                }
                if (uuid && !(*uuid = dm_pool_strdup(mem, dm_task_get_uuid(*dmt)))) {
                        log_error("uuid pool_strdup failed");
                        goto failed;
                }
                *deps = dm_task_get_deps(*dmt);
        }

        return 1;

failed:
        dm_task_destroy(*dmt);
        return 0;
}

/*
 * Deactivate a device with its dependencies if the uuid prefix matches.
 */
static int _info_by_dev(uint32_t major, uint32_t minor, int with_open_count,
                        struct dm_info *info, struct dm_pool *mem,
                        const char **name, const char **uuid)
{
        struct dm_task *dmt;
        int r;

        if (!(dmt = dm_task_create(DM_DEVICE_INFO))) {
                log_error("_info_by_dev: dm_task creation failed");
                return 0;
        }

        if (!dm_task_set_major(dmt, major) || !dm_task_set_minor(dmt, minor)) {
                log_error("_info_by_dev: Failed to set device number");
                dm_task_destroy(dmt);
                return 0;
        }

        if (!with_open_count && !dm_task_no_open_count(dmt))
                log_error("Failed to disable open_count");

        if (!(r = dm_task_run(dmt)))
                goto_out;

        if (!(r = dm_task_get_info(dmt, info)))
                goto_out;

        if (name && !(*name = dm_pool_strdup(mem, dm_task_get_name(dmt)))) {
                log_error("name pool_strdup failed");
                r = 0;
                goto_out;
        }

        if (uuid && !(*uuid = dm_pool_strdup(mem, dm_task_get_uuid(dmt)))) {
                log_error("uuid pool_strdup failed");
                r = 0;
                goto_out;
        }

out:
        dm_task_destroy(dmt);

        return r;
}

static int _check_device_not_in_use(const char *name, struct dm_info *info)
{
        if (!info->exists)
                return 1;

        /* If sysfs is not used, use open_count information only. */
        if (!*dm_sysfs_dir()) {
                if (info->open_count) {
                        log_error("Device %s (%" PRIu32 ":%" PRIu32 ") in use",
                                  name, info->major, info->minor);
                        return 0;
                }

                return 1;
        }

        if (dm_device_has_holders(info->major, info->minor)) {
                log_error("Device %s (%" PRIu32 ":%" PRIu32 ") is used "
                          "by another device.", name, info->major, info->minor);
                return 0;
        }

        if (dm_device_has_mounted_fs(info->major, info->minor)) {
                log_error("Device %s (%" PRIu32 ":%" PRIu32 ") contains "
                          "a filesystem in use.", name, info->major, info->minor);
                return 0;
        }

        return 1;
}

/* Check if all parent nodes of given node have open_count == 0 */
static int _node_has_closed_parents(struct dm_tree_node *node,
                                    const char *uuid_prefix,
                                    size_t uuid_prefix_len)
{
        struct dm_tree_link *dlink;
        const struct dm_info *dinfo;
        struct dm_info info;
        const char *uuid;

        /* Iterate through parents of this node */
        dm_list_iterate_items(dlink, &node->used_by) {
                if (!(uuid = dm_tree_node_get_uuid(dlink->node))) {
                        stack;
                        continue;
                }

                /* Ignore if it doesn't belong to this VG */
                if (!_uuid_prefix_matches(uuid, uuid_prefix, uuid_prefix_len))
                        continue;

                if (!(dinfo = dm_tree_node_get_info(dlink->node))) {
                        stack;  /* FIXME Is this normal? */
                        return 0;
                }

                /* Refresh open_count */
                if (!_info_by_dev(dinfo->major, dinfo->minor, 1, &info, NULL, NULL, NULL) ||
                    !info.exists)
                        continue;

                if (info.open_count) {
                        log_debug("Node %s %d:%d has open_count %d", uuid_prefix,
                                  dinfo->major, dinfo->minor, info.open_count);
                        return 0;
                }
        }

        return 1;
}

static int _deactivate_node(const char *name, uint32_t major, uint32_t minor,
                            uint32_t *cookie, uint16_t udev_flags, int retry)
{
        struct dm_task *dmt;
        int r = 0;

        log_verbose("Removing %s (%" PRIu32 ":%" PRIu32 ")", name, major, minor);

        if (!(dmt = dm_task_create(DM_DEVICE_REMOVE))) {
                log_error("Deactivation dm_task creation failed for %s", name);
                return 0;
        }

        if (!dm_task_set_major(dmt, major) || !dm_task_set_minor(dmt, minor)) {
                log_error("Failed to set device number for %s deactivation", name);
                goto out;
        }

        if (!dm_task_no_open_count(dmt))
                log_error("Failed to disable open_count");

        if (cookie)
                if (!dm_task_set_cookie(dmt, cookie, udev_flags))
                        goto out;

        if (retry)
                dm_task_retry_remove(dmt);

        r = dm_task_run(dmt);

        /* FIXME Until kernel returns actual name so dm-iface.c can handle it */
        rm_dev_node(name, dmt->cookie_set && !(udev_flags & DM_UDEV_DISABLE_DM_RULES_FLAG),
                    dmt->cookie_set && (udev_flags & DM_UDEV_DISABLE_LIBRARY_FALLBACK));

        /* FIXME Remove node from tree or mark invalid? */

out:
        dm_task_destroy(dmt);

        return r;
}

static int _node_clear_table(struct dm_tree_node *dnode, uint16_t udev_flags)
{
        struct dm_task *dmt = NULL, *deps_dmt = NULL;
        struct dm_info *info, deps_info;
        struct dm_deps *deps = NULL;
        const char *name, *uuid;
        const char *default_uuid_prefix;
        size_t default_uuid_prefix_len;
        uint32_t i;
        int r = 0;

        if (!(info = &dnode->info)) {
                log_error("_node_clear_table failed: missing info");
                return 0;
        }

        if (!(name = dm_tree_node_get_name(dnode))) {
                log_error("_node_clear_table failed: missing name");
                return 0;
        }

        /* Is there a table? */
        if (!info->exists || !info->inactive_table)
                return 1;

        /* Get devices used by inactive table that's about to be deleted. */
        if (!_deps(&deps_dmt, dnode->dtree->mem, info->major, info->minor, NULL, NULL, 1, info, &deps)) {
                log_error("Failed to obtain dependencies for %s before clearing table.", name);
                return 0;
        }

        log_verbose("Clearing inactive table %s (%" PRIu32 ":%" PRIu32 ")",
                    name, info->major, info->minor);

        if (!(dmt = dm_task_create(DM_DEVICE_CLEAR))) {
                log_error("Table clear dm_task creation failed for %s", name);
                goto_out;
        }

        if (!dm_task_set_major(dmt, info->major) ||
            !dm_task_set_minor(dmt, info->minor)) {
                log_error("Failed to set device number for %s table clear", name);
                goto_out;
        }

        r = dm_task_run(dmt);

        if (!dm_task_get_info(dmt, info)) {
                log_error("_node_clear_table failed: info missing after running task for %s", name);
                r = 0;
        }

        if (!r || !deps)
                goto_out;

        /*
         * Remove (incomplete) devices that the inactive table referred to but
         * which are not in the tree, no longer referenced and don't have a live
         * table.
         */
        default_uuid_prefix = dm_uuid_prefix();
        default_uuid_prefix_len = strlen(default_uuid_prefix);

        for (i = 0; i < deps->count; i++) {
                /* If already in tree, assume it's under control */
                if (_find_dm_tree_node(dnode->dtree, MAJOR(deps->device[i]), MINOR(deps->device[i])))
                        continue;

                if (!_info_by_dev(MAJOR(deps->device[i]), MINOR(deps->device[i]), 1,
                                  &deps_info, dnode->dtree->mem, &name, &uuid))
                        continue;

                /* Proceed if device is an 'orphan' - unreferenced and without a live table. */
                if (!deps_info.exists || deps_info.live_table || deps_info.open_count)
                        continue;

                if (strncmp(uuid, default_uuid_prefix, default_uuid_prefix_len))
                        continue;

                /* Remove device. */
                if (!_deactivate_node(name, deps_info.major, deps_info.minor, &dnode->dtree->cookie, udev_flags, 0)) {
                        log_error("Failed to deactivate no-longer-used device %s (%"
                                  PRIu32 ":%" PRIu32 ")", name, deps_info.major, deps_info.minor);
                } else if (deps_info.suspended)
                        dec_suspended();
        }

out:
        if (dmt)
                dm_task_destroy(dmt);

        if (deps_dmt)
                dm_task_destroy(deps_dmt);

        return r;
}

struct dm_tree_node *dm_tree_add_new_dev_with_udev_flags(struct dm_tree *dtree,
                                                         const char *name,
                                                         const char *uuid,
                                                         uint32_t major,
                                                         uint32_t minor,
                                                         int read_only,
                                                         int clear_inactive,
                                                         void *context,
                                                         uint16_t udev_flags)
{
        struct dm_tree_node *dnode;
        struct dm_info info;
        const char *name2;
        const char *uuid2;

        if (!name || !uuid) {
                log_error("Cannot add device without name and uuid.");
                return NULL;
        }

        /* Do we need to add node to tree? */
        if (!(dnode = dm_tree_find_node_by_uuid(dtree, uuid))) {
                if (!(name2 = dm_pool_strdup(dtree->mem, name))) {
                        log_error("name pool_strdup failed");
                        return NULL;
                }
                if (!(uuid2 = dm_pool_strdup(dtree->mem, uuid))) {
                        log_error("uuid pool_strdup failed");
                        return NULL;
                }

                memset(&info, 0, sizeof(info));

                if (!(dnode = _create_dm_tree_node(dtree, name2, uuid2, &info,
                                                   context, 0)))
                        return_NULL;

                /* Attach to root node until a table is supplied */
                if (!_add_to_toplevel(dnode) || !_add_to_bottomlevel(dnode))
                        return_NULL;

                dnode->props.major = major;
                dnode->props.minor = minor;
                dnode->props.new_name = NULL;
                dnode->props.size_changed = 0;
        } else if (strcmp(name, dnode->name)) {
                /* Do we need to rename node? */
                if (!(dnode->props.new_name = dm_pool_strdup(dtree->mem, name))) {
                        log_error("name pool_strdup failed");
                        return NULL;
                }
        }

        dnode->props.read_only = read_only ? 1 : 0;
        dnode->props.read_ahead = DM_READ_AHEAD_AUTO;
        dnode->props.read_ahead_flags = 0;

        if (clear_inactive && !_node_clear_table(dnode, udev_flags))
                return_NULL;

        dnode->context = context;
        dnode->udev_flags = udev_flags;

        return dnode;
}

struct dm_tree_node *dm_tree_add_new_dev(struct dm_tree *dtree, const char *name,
                                         const char *uuid, uint32_t major, uint32_t minor,
                                         int read_only, int clear_inactive, void *context)
{
        return dm_tree_add_new_dev_with_udev_flags(dtree, name, uuid, major, minor,
                                                   read_only, clear_inactive, context, 0);
}

static struct dm_tree_node *_add_dev(struct dm_tree *dtree,
                                     struct dm_tree_node *parent,
                                     uint32_t major, uint32_t minor,
                                     uint16_t udev_flags)
{
        struct dm_task *dmt = NULL;
        struct dm_info info;
        struct dm_deps *deps = NULL;
        const char *name = NULL;
        const char *uuid = NULL;
        struct dm_tree_node *node = NULL;
        uint32_t i;
        int new = 0;

        /* Already in tree? */
        if (!(node = _find_dm_tree_node(dtree, major, minor))) {
                if (!_deps(&dmt, dtree->mem, major, minor, &name, &uuid, 0, &info, &deps))
                        return_NULL;

                if (!(node = _create_dm_tree_node(dtree, name, uuid, &info,
                                                  NULL, udev_flags)))
                        goto_out;
                new = 1;
        }

        if (!_link_tree_nodes(parent, node)) {
                node = NULL;
                goto_out;
        }

        /* If node was already in tree, no need to recurse. */
        if (!new)
                goto out;

        /* Can't recurse if not a mapped device or there are no dependencies */
        if (!node->info.exists || !deps || !deps->count) {
                if (!_add_to_bottomlevel(node)) {
                        stack;
                        node = NULL;
                }
                goto out;
        }

        /* Add dependencies to tree */
        for (i = 0; i < deps->count; i++)
                if (!_add_dev(dtree, node, MAJOR(deps->device[i]),
                              MINOR(deps->device[i]), udev_flags)) {
                        node = NULL;
                        goto_out;
                }

out:
        if (dmt)
                dm_task_destroy(dmt);

        return node;
}

int dm_tree_add_dev(struct dm_tree *dtree, uint32_t major, uint32_t minor)
{
        return _add_dev(dtree, &dtree->root, major, minor, 0) ? 1 : 0;
}

int dm_tree_add_dev_with_udev_flags(struct dm_tree *dtree, uint32_t major,
                                    uint32_t minor, uint16_t udev_flags)
{
        return _add_dev(dtree, &dtree->root, major, minor, udev_flags) ? 1 : 0;
}

static int _rename_node(const char *old_name, const char *new_name, uint32_t major,
                        uint32_t minor, uint32_t *cookie, uint16_t udev_flags)
{
        struct dm_task *dmt;
        int r = 0;

        log_verbose("Renaming %s (%" PRIu32 ":%" PRIu32 ") to %s", old_name, major, minor, new_name);

        if (!(dmt = dm_task_create(DM_DEVICE_RENAME))) {
                log_error("Rename dm_task creation failed for %s", old_name);
                return 0;
        }

        if (!dm_task_set_name(dmt, old_name)) {
                log_error("Failed to set name for %s rename.", old_name);
                goto out;
        }

        if (!dm_task_set_newname(dmt, new_name))
                goto_out;

        if (!dm_task_no_open_count(dmt))
                log_error("Failed to disable open_count");

        if (!dm_task_set_cookie(dmt, cookie, udev_flags))
                goto out;

        r = dm_task_run(dmt);

out:
        dm_task_destroy(dmt);

        return r;
}

/* FIXME Merge with _suspend_node? */
static int _resume_node(const char *name, uint32_t major, uint32_t minor,
                        uint32_t read_ahead, uint32_t read_ahead_flags,
                        struct dm_info *newinfo, uint32_t *cookie,
                        uint16_t udev_flags, int already_suspended)
{
        struct dm_task *dmt;
        int r = 0;

        log_verbose("Resuming %s (%" PRIu32 ":%" PRIu32 ")", name, major, minor);

        if (!(dmt = dm_task_create(DM_DEVICE_RESUME))) {
                log_debug("Suspend dm_task creation failed for %s.", name);
                return 0;
        }

        /* FIXME Kernel should fill in name on return instead */
        if (!dm_task_set_name(dmt, name)) {
                log_debug("Failed to set device name for %s resumption.", name);
                goto out;
        }

        if (!dm_task_set_major(dmt, major) || !dm_task_set_minor(dmt, minor)) {
                log_error("Failed to set device number for %s resumption.", name);
                goto out;
        }

        if (!dm_task_no_open_count(dmt))
                log_error("Failed to disable open_count");

        if (!dm_task_set_read_ahead(dmt, read_ahead, read_ahead_flags))
                log_error("Failed to set read ahead");

        if (!dm_task_set_cookie(dmt, cookie, udev_flags))
                goto_out;

        if (!(r = dm_task_run(dmt)))
                goto_out;

        if (already_suspended)
                dec_suspended();

        if (!(r = dm_task_get_info(dmt, newinfo)))
                stack;

out:
        dm_task_destroy(dmt);

        return r;
}

static int _suspend_node(const char *name, uint32_t major, uint32_t minor,
                         int skip_lockfs, int no_flush, struct dm_info *newinfo)
{
        struct dm_task *dmt;
        int r;

        log_verbose("Suspending %s (%" PRIu32 ":%" PRIu32 ")%s%s",
                    name, major, minor,
                    skip_lockfs ? "" : " with filesystem sync",
                    no_flush ? "" : " with device flush");

        if (!(dmt = dm_task_create(DM_DEVICE_SUSPEND))) {
                log_error("Suspend dm_task creation failed for %s", name);
                return 0;
        }

        if (!dm_task_set_major(dmt, major) || !dm_task_set_minor(dmt, minor)) {
                log_error("Failed to set device number for %s suspension.", name);
                dm_task_destroy(dmt);
                return 0;
        }

        if (!dm_task_no_open_count(dmt))
                log_error("Failed to disable open_count");

        if (skip_lockfs && !dm_task_skip_lockfs(dmt))
                log_error("Failed to set skip_lockfs flag.");

        if (no_flush && !dm_task_no_flush(dmt))
                log_error("Failed to set no_flush flag.");

        if ((r = dm_task_run(dmt))) {
                inc_suspended();
                r = dm_task_get_info(dmt, newinfo);
        }

        dm_task_destroy(dmt);

        return r;
}

static int _thin_pool_status_transaction_id(struct dm_tree_node *dnode, uint64_t *transaction_id)
{
        struct dm_task *dmt;
        int r = 0;
        uint64_t start, length;
        char *type = NULL;
        char *params = NULL;

        if (!(dmt = dm_task_create(DM_DEVICE_STATUS)))
                return_0;

        if (!dm_task_set_major(dmt, dnode->info.major) ||
            !dm_task_set_minor(dmt, dnode->info.minor)) {
                log_error("Failed to set major minor.");
                goto out;
        }

        if (!dm_task_run(dmt))
                goto_out;

        dm_get_next_target(dmt, NULL, &start, &length, &type, &params);

        if (type && (strcmp(type, "thin-pool") != 0)) {
                log_error("Expected thin-pool target for %d:%d and got %s.",
                          dnode->info.major, dnode->info.minor, type);
                goto out;
        }

        if (!params || (sscanf(params, "%" PRIu64, transaction_id) != 1)) {
                log_error("Failed to parse transaction_id from %s.", params);
                goto out;
        }

        log_debug("Thin pool transaction id: %" PRIu64 " status: %s.", *transaction_id, params);

        r = 1;
out:
        dm_task_destroy(dmt);

        return r;
}

static int _thin_pool_node_message(struct dm_tree_node *dnode, struct thin_message *tm)
{
        struct dm_task *dmt;
        struct dm_thin_message *m = &tm->message;
        char buf[64];
        int r;

        switch (m->type) {
        case DM_THIN_MESSAGE_CREATE_SNAP:
                r = dm_snprintf(buf, sizeof(buf), "create_snap %u %u",
                                m->u.m_create_snap.device_id,
                                m->u.m_create_snap.origin_id);
                break;
        case DM_THIN_MESSAGE_CREATE_THIN:
                r = dm_snprintf(buf, sizeof(buf), "create_thin %u",
                                m->u.m_create_thin.device_id);
                break;
        case DM_THIN_MESSAGE_DELETE:
                r = dm_snprintf(buf, sizeof(buf), "delete %u",
                                m->u.m_delete.device_id);
                break;
        case DM_THIN_MESSAGE_SET_TRANSACTION_ID:
                r = dm_snprintf(buf, sizeof(buf),
                                "set_transaction_id %" PRIu64 " %" PRIu64,
                                m->u.m_set_transaction_id.current_id,
                                m->u.m_set_transaction_id.new_id);
                break;
        default:
                r = -1;
        }

        if (r < 0) {
                log_error("Failed to prepare message.");
                return 0;
        }

        r = 0;

        if (!(dmt = dm_task_create(DM_DEVICE_TARGET_MSG)))
                return_0;

        if (!dm_task_set_major(dmt, dnode->info.major) ||
            !dm_task_set_minor(dmt, dnode->info.minor)) {
                log_error("Failed to set message major minor.");
                goto out;
        }

        if (!dm_task_set_message(dmt, buf))
                goto_out;

        /* Internal functionality of dm_task */
        dmt->expected_errno = tm->expected_errno;

        if (!dm_task_run(dmt))
                goto_out;

        r = 1;
out:
        dm_task_destroy(dmt);

        return r;
}

static int _node_send_messages(struct dm_tree_node *dnode,
                               const char *uuid_prefix,
                               size_t uuid_prefix_len)
{
        struct load_segment *seg;
        struct thin_message *tmsg;
        uint64_t trans_id;
        const char *uuid;

        if (!dnode->info.exists || (dm_list_size(&dnode->props.segs) != 1))
                return 1;

        seg = dm_list_item(dm_list_last(&dnode->props.segs), struct load_segment);
        if (seg->type != SEG_THIN_POOL)
                return 1;

        if (!(uuid = dm_tree_node_get_uuid(dnode)))
                return_0;

        if (!_uuid_prefix_matches(uuid, uuid_prefix, uuid_prefix_len)) {
                log_debug("UUID \"%s\" does not match.", uuid);
                return 1;
        }

        if (!_thin_pool_status_transaction_id(dnode, &trans_id))
                goto_bad;

        if (trans_id == seg->transaction_id)
                return 1; /* In sync - skip messages */

        if (trans_id != (seg->transaction_id - 1)) {
                log_error("Thin pool transaction_id=%" PRIu64 ", while expected: %" PRIu64 ".",
                          trans_id, seg->transaction_id - 1);
                goto bad; /* Nothing to send */
        }

        dm_list_iterate_items(tmsg, &seg->thin_messages)
                if (!(_thin_pool_node_message(dnode, tmsg)))
                        goto_bad;

        return 1;
bad:
        /* Try to deactivate */
        if (!(dm_tree_deactivate_children(dnode, uuid_prefix, uuid_prefix_len)))
                log_error("Failed to deactivate %s", dnode->name);

        return 0;
}

/*
 * FIXME Don't attempt to deactivate known internal dependencies.
 */
static int _dm_tree_deactivate_children(struct dm_tree_node *dnode,
                                        const char *uuid_prefix,
                                        size_t uuid_prefix_len,
                                        unsigned level)
{
        int r = 1;
        void *handle = NULL;
        struct dm_tree_node *child = dnode;
        struct dm_info info;
        const struct dm_info *dinfo;
        const char *name;
        const char *uuid;

        while ((child = dm_tree_next_child(&handle, dnode, 0))) {
                if (!(dinfo = dm_tree_node_get_info(child))) {
                        stack;
                        continue;
                }

                if (!(name = dm_tree_node_get_name(child))) {
                        stack;
                        continue;
                }

                if (!(uuid = dm_tree_node_get_uuid(child))) {
                        stack;
                        continue;
                }

                /* Ignore if it doesn't belong to this VG */
                if (!_uuid_prefix_matches(uuid, uuid_prefix, uuid_prefix_len))
                        continue;

                /* Refresh open_count */
                if (!_info_by_dev(dinfo->major, dinfo->minor, 1, &info, NULL, NULL, NULL) ||
                    !info.exists)
                        continue;

                if (info.open_count) {
                        /* Skip internal non-toplevel opened nodes */
                        if (level)
                                continue;

                        /* When retry is not allowed, error */
                        if (!child->dtree->retry_remove) {
                                log_error("Unable to deactivate open %s (%" PRIu32
                                          ":%" PRIu32 ")", name, info.major, info.minor);
                                r = 0;
                                continue;
                        }

                        /* Check toplevel node for holders/mounted fs */
                        if (!_check_device_not_in_use(name, &info)) {
                                stack;
                                r = 0;
                                continue;
                        }
                        /* Go on with retry */
                }

                /* Also checking open_count in parent nodes of presuspend_node */
                if ((child->presuspend_node &&
                     !_node_has_closed_parents(child->presuspend_node,
                                               uuid_prefix, uuid_prefix_len))) {
                        /* Only report error from (likely non-internal) dependency at top level */
                        if (!level) {
                                log_error("Unable to deactivate open %s (%" PRIu32
                                          ":%" PRIu32 ")", name, info.major,
                                        info.minor);
                                r = 0;
                        }
                        continue;
                }

                /* Suspend child node first if requested */
                if (child->presuspend_node &&
                    !dm_tree_suspend_children(child, uuid_prefix, uuid_prefix_len))
                        continue;

                if (!_deactivate_node(name, info.major, info.minor,
                                      &child->dtree->cookie, child->udev_flags,
                                      (level == 0) ? child->dtree->retry_remove : 0)) {
                        log_error("Unable to deactivate %s (%" PRIu32
                                  ":%" PRIu32 ")", name, info.major,
                                  info.minor);
                        r = 0;
                        continue;
                } else if (info.suspended)
                        dec_suspended();

                if (child->callback &&
                    !child->callback(child, DM_NODE_CALLBACK_DEACTIVATED,
                                     child->callback_data))
                        stack;
                        // FIXME: We need to let lvremove pass,
                        // so for now deactivation ignores check result
                        //r = 0; // FIXME: _node_clear_table() without callback ?

                if (dm_tree_node_num_children(child, 0) &&
                    !_dm_tree_deactivate_children(child, uuid_prefix, uuid_prefix_len, level + 1))
                        return_0;
        }

        return r;
}

int dm_tree_deactivate_children(struct dm_tree_node *dnode,
                                   const char *uuid_prefix,
                                   size_t uuid_prefix_len)
{
        return _dm_tree_deactivate_children(dnode, uuid_prefix, uuid_prefix_len, 0);
}

int dm_tree_suspend_children(struct dm_tree_node *dnode,
                             const char *uuid_prefix,
                             size_t uuid_prefix_len)
{
        int r = 1;
        void *handle = NULL;
        struct dm_tree_node *child = dnode;
        struct dm_info info, newinfo;
        const struct dm_info *dinfo;
        const char *name;
        const char *uuid;

        /* Suspend nodes at this level of the tree */
        while ((child = dm_tree_next_child(&handle, dnode, 0))) {
                if (!(dinfo = dm_tree_node_get_info(child))) {
                        stack;
                        continue;
                }

                if (!(name = dm_tree_node_get_name(child))) {
                        stack;
                        continue;
                }

                if (!(uuid = dm_tree_node_get_uuid(child))) {
                        stack;
                        continue;
                }

                /* Ignore if it doesn't belong to this VG */
                if (!_uuid_prefix_matches(uuid, uuid_prefix, uuid_prefix_len))
                        continue;

                /* Ensure immediate parents are already suspended */
                if (!_children_suspended(child, 1, uuid_prefix, uuid_prefix_len))
                        continue;

                if (!_info_by_dev(dinfo->major, dinfo->minor, 0, &info, NULL, NULL, NULL) ||
                    !info.exists || info.suspended)
                        continue;

                if (!_suspend_node(name, info.major, info.minor,
                                   child->dtree->skip_lockfs,
                                   child->dtree->no_flush, &newinfo)) {
                        log_error("Unable to suspend %s (%" PRIu32
                                  ":%" PRIu32 ")", name, info.major,
                                  info.minor);
                        r = 0;
                        continue;
                }

                /* Update cached info */
                child->info = newinfo;
        }

        /* Then suspend any child nodes */
        handle = NULL;

        while ((child = dm_tree_next_child(&handle, dnode, 0))) {
                if (!(uuid = dm_tree_node_get_uuid(child))) {
                        stack;
                        continue;
                }

                /* Ignore if it doesn't belong to this VG */
                if (!_uuid_prefix_matches(uuid, uuid_prefix, uuid_prefix_len))
                        continue;

                if (dm_tree_node_num_children(child, 0))
                        if (!dm_tree_suspend_children(child, uuid_prefix, uuid_prefix_len))
                                return_0;
        }

        return r;
}

int dm_tree_activate_children(struct dm_tree_node *dnode,
                                 const char *uuid_prefix,
                                 size_t uuid_prefix_len)
{
        int r = 1;
        void *handle = NULL;
        struct dm_tree_node *child = dnode;
        struct dm_info newinfo;
        const char *name;
        const char *uuid;
        int priority;

        /* Activate children first */
        while ((child = dm_tree_next_child(&handle, dnode, 0))) {
                if (!(uuid = dm_tree_node_get_uuid(child))) {
                        stack;
                        continue;
                }

                if (!_uuid_prefix_matches(uuid, uuid_prefix, uuid_prefix_len))
                        continue;

                if (dm_tree_node_num_children(child, 0))
                        if (!dm_tree_activate_children(child, uuid_prefix, uuid_prefix_len))
                                return_0;
        }

        handle = NULL;

        for (priority = 0; priority < 3; priority++) {
                while ((child = dm_tree_next_child(&handle, dnode, 0))) {
                        if (priority != child->activation_priority)
                                continue;

                        if (!(uuid = dm_tree_node_get_uuid(child))) {
                                stack;
                                continue;
                        }

                        if (!_uuid_prefix_matches(uuid, uuid_prefix, uuid_prefix_len))
                                continue;

                        if (!(name = dm_tree_node_get_name(child))) {
                                stack;
                                continue;
                        }

                        /* Rename? */
                        if (child->props.new_name) {
                                if (!_rename_node(name, child->props.new_name, child->info.major,
                                                  child->info.minor, &child->dtree->cookie,
                                                  child->udev_flags)) {
                                        log_error("Failed to rename %s (%" PRIu32
                                                  ":%" PRIu32 ") to %s", name, child->info.major,
                                                  child->info.minor, child->props.new_name);
                                        return 0;
                                }
                                child->name = child->props.new_name;
                                child->props.new_name = NULL;
                        }

                        if (!child->info.inactive_table && !child->info.suspended)
                                continue;

                        if (!_resume_node(child->name, child->info.major, child->info.minor,
                                          child->props.read_ahead, child->props.read_ahead_flags,
                                          &newinfo, &child->dtree->cookie, child->udev_flags, child->info.suspended)) {
                                log_error("Unable to resume %s (%" PRIu32
                                          ":%" PRIu32 ")", child->name, child->info.major,
                                          child->info.minor);
                                r = 0;
                                continue;
                        }

                        /* Update cached info */
                        child->info = newinfo;
                }
        }

        /*
         * FIXME: Implement delayed error reporting
         * activation should be stopped only in the case,
         * the submission of transation_id message fails,
         * resume should continue further, just whole command
         * has to report failure.
         */
        if (r && dnode->props.send_messages &&
            !(r = _node_send_messages(dnode, uuid_prefix, uuid_prefix_len)))
                stack;

        handle = NULL;

        return r;
}

static int _create_node(struct dm_tree_node *dnode)
{
        int r = 0;
        struct dm_task *dmt;

        log_verbose("Creating %s", dnode->name);

        if (!(dmt = dm_task_create(DM_DEVICE_CREATE))) {
                log_error("Create dm_task creation failed for %s", dnode->name);
                return 0;
        }

        if (!dm_task_set_name(dmt, dnode->name)) {
                log_error("Failed to set device name for %s", dnode->name);
                goto out;
        }

        if (!dm_task_set_uuid(dmt, dnode->uuid)) {
                log_error("Failed to set uuid for %s", dnode->name);
                goto out;
        }

        if (dnode->props.major &&
            (!dm_task_set_major(dmt, dnode->props.major) ||
             !dm_task_set_minor(dmt, dnode->props.minor))) {
                log_error("Failed to set device number for %s creation.", dnode->name);
                goto out;
        }

        if (dnode->props.read_only && !dm_task_set_ro(dmt)) {
                log_error("Failed to set read only flag for %s", dnode->name);
                goto out;
        }

        if (!dm_task_no_open_count(dmt))
                log_error("Failed to disable open_count");

        if ((r = dm_task_run(dmt)))
                r = dm_task_get_info(dmt, &dnode->info);

out:
        dm_task_destroy(dmt);

        return r;
}


static int _build_dev_string(char *devbuf, size_t bufsize, struct dm_tree_node *node)
{
        if (!dm_format_dev(devbuf, bufsize, node->info.major, node->info.minor)) {
                log_error("Failed to format %s device number for %s as dm "
                          "target (%u,%u)",
                          node->name, node->uuid, node->info.major, node->info.minor);
                return 0;
        }

        return 1;
}

/* simplify string emiting code */
#define EMIT_PARAMS(p, str...)\
do {\
        int w;\
        if ((w = dm_snprintf(params + p, paramsize - (size_t) p, str)) < 0) {\
                stack; /* Out of space */\
                return -1;\
        }\
        p += w;\
} while (0)

/*
 * _emit_areas_line
 *
 * Returns: 1 on success, 0 on failure
 */
static int _emit_areas_line(struct dm_task *dmt __attribute__((unused)),
                            struct load_segment *seg, char *params,
                            size_t paramsize, int *pos)
{
        struct seg_area *area;
        char devbuf[DM_FORMAT_DEV_BUFSIZE];
        unsigned first_time = 1;
        const char *logtype, *synctype;
        unsigned log_parm_count;

        dm_list_iterate_items(area, &seg->areas) {
                switch (seg->type) {
                case SEG_REPLICATOR_DEV:
                        if (!_build_dev_string(devbuf, sizeof(devbuf), area->dev_node))
                                return_0;

                        EMIT_PARAMS(*pos, " %d 1 %s", area->rsite_index, devbuf);
                        if (first_time)
                                EMIT_PARAMS(*pos, " nolog 0");
                        else {
                                /* Remote devices */
                                log_parm_count = (area->flags &
                                                  (DM_NOSYNC | DM_FORCESYNC)) ? 2 : 1;

                                if (!area->slog) {
                                        devbuf[0] = 0;          /* Only core log parameters */
                                        logtype = "core";
                                } else {
                                        devbuf[0] = ' ';        /* Extra space before device name */
                                        if (!_build_dev_string(devbuf + 1,
                                                               sizeof(devbuf) - 1,
                                                               area->slog))
                                                return_0;
                                        logtype = "disk";
                                        log_parm_count++;       /* Extra sync log device name parameter */
                                }

                                EMIT_PARAMS(*pos, " %s %u%s %" PRIu64, logtype,
                                            log_parm_count, devbuf, area->region_size);

                                synctype = (area->flags & DM_NOSYNC) ?
                                                " nosync" : (area->flags & DM_FORCESYNC) ?
                                                                " sync" : NULL;

                                if (synctype)
                                        EMIT_PARAMS(*pos, "%s", synctype);
                        }
                        break;
                case SEG_RAID1:
                case SEG_RAID4:
                case SEG_RAID5_LA:
                case SEG_RAID5_RA:
                case SEG_RAID5_LS:
                case SEG_RAID5_RS:
                case SEG_RAID6_ZR:
                case SEG_RAID6_NR:
                case SEG_RAID6_NC:
                        if (!area->dev_node) {
                                EMIT_PARAMS(*pos, " -");
                                break;
                        }
                        if (!_build_dev_string(devbuf, sizeof(devbuf), area->dev_node))
                                return_0;

                        EMIT_PARAMS(*pos, " %s", devbuf);
                        break;
                default:
                        if (!_build_dev_string(devbuf, sizeof(devbuf), area->dev_node))
                                return_0;

                        EMIT_PARAMS(*pos, "%s%s %" PRIu64, first_time ? "" : " ",
                                    devbuf, area->offset);
                }

                first_time = 0;
        }

        return 1;
}

static int _replicator_emit_segment_line(const struct load_segment *seg, char *params,
                                         size_t paramsize, int *pos)
{
        const struct load_segment *rlog_seg;
        struct replicator_site *rsite;
        char rlogbuf[DM_FORMAT_DEV_BUFSIZE];
        unsigned parm_count;

        if (!seg->log || !_build_dev_string(rlogbuf, sizeof(rlogbuf), seg->log))
                return_0;

        rlog_seg = dm_list_item(dm_list_last(&seg->log->props.segs),
                                struct load_segment);

        EMIT_PARAMS(*pos, "%s 4 %s 0 auto %" PRIu64,
                    seg->rlog_type, rlogbuf, rlog_seg->size);

        dm_list_iterate_items(rsite, &seg->rsites) {
                parm_count = (rsite->fall_behind_data
                              || rsite->fall_behind_ios
                              || rsite->async_timeout) ? 4 : 2;

                EMIT_PARAMS(*pos, " blockdev %u %u %s", parm_count, rsite->rsite_index,
                            (rsite->mode == DM_REPLICATOR_SYNC) ? "synchronous" : "asynchronous");

                if (rsite->fall_behind_data)
                        EMIT_PARAMS(*pos, " data %" PRIu64, rsite->fall_behind_data);
                else if (rsite->fall_behind_ios)
                        EMIT_PARAMS(*pos, " ios %" PRIu32, rsite->fall_behind_ios);
                else if (rsite->async_timeout)
                        EMIT_PARAMS(*pos, " timeout %" PRIu32, rsite->async_timeout);
        }

        return 1;
}

/*
 * Returns: 1 on success, 0 on failure
 */
static int _mirror_emit_segment_line(struct dm_task *dmt, struct load_segment *seg,
                                     char *params, size_t paramsize)
{
        int block_on_error = 0;
        int handle_errors = 0;
        int dm_log_userspace = 0;
        struct utsname uts;
        unsigned log_parm_count;
        int pos = 0, parts;
        char logbuf[DM_FORMAT_DEV_BUFSIZE];
        const char *logtype;
        unsigned kmaj = 0, kmin = 0, krel = 0;

        if (uname(&uts) == -1) {
                log_error("Cannot read kernel release version.");
                return 0;
        }

        /* Kernels with a major number of 2 always had 3 parts. */
        parts = sscanf(uts.release, "%u.%u.%u", &kmaj, &kmin, &krel);
        if (parts < 1 || (kmaj < 3 && parts < 3)) {
                log_error("Wrong kernel release version %s.", uts.release);
                return 0;
        }

        if ((seg->flags & DM_BLOCK_ON_ERROR)) {
                /*
                 * Originally, block_on_error was an argument to the log
                 * portion of the mirror CTR table.  It was renamed to
                 * "handle_errors" and now resides in the 'features'
                 * section of the mirror CTR table (i.e. at the end).
                 *
                 * We can identify whether to use "block_on_error" or
                 * "handle_errors" by the dm-mirror module's version
                 * number (>= 1.12) or by the kernel version (>= 2.6.22).
                 */
                if (KERNEL_VERSION(kmaj, kmin, krel) >= KERNEL_VERSION(2, 6, 22))
                        handle_errors = 1;
                else
                        block_on_error = 1;
        }

        if (seg->clustered) {
                /* Cluster mirrors require a UUID */
                if (!seg->uuid)
                        return_0;

                /*
                 * Cluster mirrors used to have their own log
                 * types.  Now they are accessed through the
                 * userspace log type.
                 *
                 * The dm-log-userspace module was added to the
                 * 2.6.31 kernel.
                 */
                if (KERNEL_VERSION(kmaj, kmin, krel) >= KERNEL_VERSION(2, 6, 31))
                        dm_log_userspace = 1;
        }

        /* Region size */
        log_parm_count = 1;

        /* [no]sync, block_on_error etc. */
        log_parm_count += hweight32(seg->flags);

        /* "handle_errors" is a feature arg now */
        if (handle_errors)
                log_parm_count--;

        /* DM_CORELOG does not count in the param list */
        if (seg->flags & DM_CORELOG)
                log_parm_count--;

        if (seg->clustered) {
                log_parm_count++; /* For UUID */

                if (!dm_log_userspace)
                        EMIT_PARAMS(pos, "clustered-");
                else
                        /* For clustered-* type field inserted later */
                        log_parm_count++;
        }

        if (!seg->log)
                logtype = "core";
        else {
                logtype = "disk";
                log_parm_count++;
                if (!_build_dev_string(logbuf, sizeof(logbuf), seg->log))
                        return_0;
        }

        if (dm_log_userspace)
                EMIT_PARAMS(pos, "userspace %u %s clustered-%s",
                            log_parm_count, seg->uuid, logtype);
        else
                EMIT_PARAMS(pos, "%s %u", logtype, log_parm_count);

        if (seg->log)
                EMIT_PARAMS(pos, " %s", logbuf);

        EMIT_PARAMS(pos, " %u", seg->region_size);

        if (seg->clustered && !dm_log_userspace)
                EMIT_PARAMS(pos, " %s", seg->uuid);

        if ((seg->flags & DM_NOSYNC))
                EMIT_PARAMS(pos, " nosync");
        else if ((seg->flags & DM_FORCESYNC))
                EMIT_PARAMS(pos, " sync");

        if (block_on_error)
                EMIT_PARAMS(pos, " block_on_error");

        EMIT_PARAMS(pos, " %u ", seg->mirror_area_count);

        if (_emit_areas_line(dmt, seg, params, paramsize, &pos) <= 0)
                return_0;

        if (handle_errors)
                EMIT_PARAMS(pos, " 1 handle_errors");

        return 1;
}

static int _raid_emit_segment_line(struct dm_task *dmt, uint32_t major,
                                   uint32_t minor, struct load_segment *seg,
                                   uint64_t *seg_start, char *params,
                                   size_t paramsize)
{
        uint32_t i;
        int param_count = 1; /* mandatory 'chunk size'/'stripe size' arg */
        int pos = 0;

        if ((seg->flags & DM_NOSYNC) || (seg->flags & DM_FORCESYNC))
                param_count++;

        if (seg->region_size)
                param_count += 2;

        /* rebuilds is 64-bit */
        param_count += 2 * hweight32(seg->rebuilds & 0xFFFFFFFF);
        param_count += 2 * hweight32(seg->rebuilds >> 32);

        if ((seg->type == SEG_RAID1) && seg->stripe_size)
                log_error("WARNING: Ignoring RAID1 stripe size");

        EMIT_PARAMS(pos, "%s %d %u", dm_segtypes[seg->type].target,
                    param_count, seg->stripe_size);

        if (seg->flags & DM_NOSYNC)
                EMIT_PARAMS(pos, " nosync");
        else if (seg->flags & DM_FORCESYNC)
                EMIT_PARAMS(pos, " sync");

        if (seg->region_size)
                EMIT_PARAMS(pos, " region_size %u", seg->region_size);

        for (i = 0; i < (seg->area_count / 2); i++)
                if (seg->rebuilds & (1 << i))
                        EMIT_PARAMS(pos, " rebuild %u", i);

        /* Print number of metadata/data device pairs */
        EMIT_PARAMS(pos, " %u", seg->area_count/2);

        if (_emit_areas_line(dmt, seg, params, paramsize, &pos) <= 0)
                return_0;

        return 1;
}

static int _emit_segment_line(struct dm_task *dmt, uint32_t major,
                              uint32_t minor, struct load_segment *seg,
                              uint64_t *seg_start, char *params,
                              size_t paramsize)
{
        int pos = 0;
        int r;
        int target_type_is_raid = 0;
        char originbuf[DM_FORMAT_DEV_BUFSIZE], cowbuf[DM_FORMAT_DEV_BUFSIZE];
        char pool[DM_FORMAT_DEV_BUFSIZE], metadata[DM_FORMAT_DEV_BUFSIZE];

        switch(seg->type) {
        case SEG_ERROR:
        case SEG_ZERO:
        case SEG_LINEAR:
                break;
        case SEG_MIRRORED:
                /* Mirrors are pretty complicated - now in separate function */
                r = _mirror_emit_segment_line(dmt, seg, params, paramsize);
                if (!r)
                        return_0;
                break;
        case SEG_REPLICATOR:
                if ((r = _replicator_emit_segment_line(seg, params, paramsize,
                                                       &pos)) <= 0) {
                        stack;
                        return r;
                }
                break;
        case SEG_REPLICATOR_DEV:
                if (!seg->replicator || !_build_dev_string(originbuf,
                                                           sizeof(originbuf),
                                                           seg->replicator))
                        return_0;

                EMIT_PARAMS(pos, "%s %" PRIu64, originbuf, seg->rdevice_index);
                break;
        case SEG_SNAPSHOT:
        case SEG_SNAPSHOT_MERGE:
                if (!_build_dev_string(originbuf, sizeof(originbuf), seg->origin))
                        return_0;
                if (!_build_dev_string(cowbuf, sizeof(cowbuf), seg->cow))
                        return_0;
                EMIT_PARAMS(pos, "%s %s %c %d", originbuf, cowbuf,
                            seg->persistent ? 'P' : 'N', seg->chunk_size);
                break;
        case SEG_SNAPSHOT_ORIGIN:
                if (!_build_dev_string(originbuf, sizeof(originbuf), seg->origin))
                        return_0;
                EMIT_PARAMS(pos, "%s", originbuf);
                break;
        case SEG_STRIPED:
                EMIT_PARAMS(pos, "%u %u ", seg->area_count, seg->stripe_size);
                break;
        case SEG_CRYPT:
                EMIT_PARAMS(pos, "%s%s%s%s%s %s %" PRIu64 " ", seg->cipher,
                            seg->chainmode ? "-" : "", seg->chainmode ?: "",
                            seg->iv ? "-" : "", seg->iv ?: "", seg->key,
                            seg->iv_offset != DM_CRYPT_IV_DEFAULT ?
                            seg->iv_offset : *seg_start);
                break;
        case SEG_RAID1:
        case SEG_RAID4:
        case SEG_RAID5_LA:
        case SEG_RAID5_RA:
        case SEG_RAID5_LS:
        case SEG_RAID5_RS:
        case SEG_RAID6_ZR:
        case SEG_RAID6_NR:
        case SEG_RAID6_NC:
                target_type_is_raid = 1;
                r = _raid_emit_segment_line(dmt, major, minor, seg, seg_start,
                                            params, paramsize);
                if (!r)
                        return_0;

                break;
        case SEG_THIN_POOL:
                if (!_build_dev_string(metadata, sizeof(metadata), seg->metadata))
                        return_0;
                if (!_build_dev_string(pool, sizeof(pool), seg->pool))
                        return_0;
                EMIT_PARAMS(pos, "%s %s %d %" PRIu64 " %s", metadata, pool,
                            seg->data_block_size, seg->low_water_mark,
                            seg->skip_block_zeroing ? "1 skip_block_zeroing" : "0");
                break;
        case SEG_THIN:
                if (!_build_dev_string(pool, sizeof(pool), seg->pool))
                        return_0;
                EMIT_PARAMS(pos, "%s %d", pool, seg->device_id);
                break;
        }

        switch(seg->type) {
        case SEG_ERROR:
        case SEG_REPLICATOR:
        case SEG_SNAPSHOT:
        case SEG_SNAPSHOT_ORIGIN:
        case SEG_SNAPSHOT_MERGE:
        case SEG_ZERO:
        case SEG_THIN_POOL:
        case SEG_THIN:
                break;
        case SEG_CRYPT:
        case SEG_LINEAR:
        case SEG_REPLICATOR_DEV:
        case SEG_STRIPED:
                if ((r = _emit_areas_line(dmt, seg, params, paramsize, &pos)) <= 0) {
                        stack;
                        return r;
                }
                if (!params[0]) {
                        log_error("No parameters supplied for %s target "
                                  "%u:%u.", dm_segtypes[seg->type].target,
                                  major, minor);
                        return 0;
                }
                break;
        }

        log_debug("Adding target to (%" PRIu32 ":%" PRIu32 "): %" PRIu64
                  " %" PRIu64 " %s %s", major, minor,
                  *seg_start, seg->size, target_type_is_raid ? "raid" :
                  dm_segtypes[seg->type].target, params);

        if (!dm_task_add_target(dmt, *seg_start, seg->size,
                                target_type_is_raid ? "raid" :
                                dm_segtypes[seg->type].target, params))
                return_0;

        *seg_start += seg->size;

        return 1;
}

#undef EMIT_PARAMS

static int _emit_segment(struct dm_task *dmt, uint32_t major, uint32_t minor,
                         struct load_segment *seg, uint64_t *seg_start)
{
        char *params;
        size_t paramsize = 4096;
        int ret;

        do {
                if (!(params = dm_malloc(paramsize))) {
                        log_error("Insufficient space for target parameters.");
                        return 0;
                }

                params[0] = '\0';
                ret = _emit_segment_line(dmt, major, minor, seg, seg_start,
                                         params, paramsize);
                dm_free(params);

                if (!ret)
                        stack;

                if (ret >= 0)
                        return ret;

                log_debug("Insufficient space in params[%" PRIsize_t
                          "] for target parameters.", paramsize);

                paramsize *= 2;
        } while (paramsize < MAX_TARGET_PARAMSIZE);

        log_error("Target parameter size too big. Aborting.");
        return 0;
}

static int _load_node(struct dm_tree_node *dnode)
{
        int r = 0;
        struct dm_task *dmt;
        struct load_segment *seg;
        uint64_t seg_start = 0, existing_table_size;

        log_verbose("Loading %s table (%" PRIu32 ":%" PRIu32 ")", dnode->name,
                    dnode->info.major, dnode->info.minor);

        if (!(dmt = dm_task_create(DM_DEVICE_RELOAD))) {
                log_error("Reload dm_task creation failed for %s", dnode->name);
                return 0;
        }

        if (!dm_task_set_major(dmt, dnode->info.major) ||
            !dm_task_set_minor(dmt, dnode->info.minor)) {
                log_error("Failed to set device number for %s reload.", dnode->name);
                goto out;
        }

        if (dnode->props.read_only && !dm_task_set_ro(dmt)) {
                log_error("Failed to set read only flag for %s", dnode->name);
                goto out;
        }

        if (!dm_task_no_open_count(dmt))
                log_error("Failed to disable open_count");

        dm_list_iterate_items(seg, &dnode->props.segs)
                if (!_emit_segment(dmt, dnode->info.major, dnode->info.minor,
                                   seg, &seg_start))
                        goto_out;

        if (!dm_task_suppress_identical_reload(dmt))
                log_error("Failed to suppress reload of identical tables.");

        if ((r = dm_task_run(dmt))) {
                r = dm_task_get_info(dmt, &dnode->info);
                if (r && !dnode->info.inactive_table)
                        log_verbose("Suppressed %s (%" PRIu32 ":%" PRIu32
                                    ") identical table reload.",
                                    dnode->name,
                                    dnode->info.major, dnode->info.minor);

                existing_table_size = dm_task_get_existing_table_size(dmt);
                if ((dnode->props.size_changed =
                     (existing_table_size == seg_start) ? 0 : 1)) {
                        /*
                         * Kernel usually skips size validation on zero-length devices
                         * now so no need to preload them.
                         */
                        /* FIXME In which kernel version did this begin? */
                        if (!existing_table_size && dnode->props.delay_resume_if_new)
                                dnode->props.size_changed = 0;

                        log_debug("Table size changed from %" PRIu64 " to %"
                                  PRIu64 " for %s (%" PRIu32 ":%" PRIu32 ").%s",
                                  existing_table_size, seg_start, dnode->name,
                                  dnode->info.major, dnode->info.minor,
                                  dnode->props.size_changed ? "" : " (Ignoring.)");
                }
        }

        dnode->props.segment_count = 0;

out:
        dm_task_destroy(dmt);

        return r;
}

int dm_tree_preload_children(struct dm_tree_node *dnode,
                             const char *uuid_prefix,
                             size_t uuid_prefix_len)
{
        int r = 1;
        void *handle = NULL;
        struct dm_tree_node *child;
        struct dm_info newinfo;
        int update_devs_flag = 0;

        /* Preload children first */
        while ((child = dm_tree_next_child(&handle, dnode, 0))) {
                /* Skip existing non-device-mapper devices */
                if (!child->info.exists && child->info.major)
                        continue;

                /* Ignore if it doesn't belong to this VG */
                if (child->info.exists &&
                    !_uuid_prefix_matches(child->uuid, uuid_prefix, uuid_prefix_len))
                        continue;

                if (dm_tree_node_num_children(child, 0))
                        if (!dm_tree_preload_children(child, uuid_prefix, uuid_prefix_len))
                                return_0;

                /* FIXME Cope if name exists with no uuid? */
                if (!child->info.exists && !_create_node(child))
                        return_0;

                if (!child->info.inactive_table &&
                    child->props.segment_count &&
                    !_load_node(child))
                        return_0;

                /* Propagate device size change change */
                if (child->props.size_changed)
                        dnode->props.size_changed = 1;

                /* Resume device immediately if it has parents and its size changed */
                if (!dm_tree_node_num_children(child, 1) || !child->props.size_changed)
                        continue;

                if (!child->info.inactive_table && !child->info.suspended)
                        continue;

                if (!_resume_node(child->name, child->info.major, child->info.minor,
                                  child->props.read_ahead, child->props.read_ahead_flags,
                                  &newinfo, &child->dtree->cookie, child->udev_flags,
                                  child->info.suspended)) {
                        log_error("Unable to resume %s (%" PRIu32
                                  ":%" PRIu32 ")", child->name, child->info.major,
                                  child->info.minor);
                        r = 0;
                        continue;
                }

                /* Update cached info */
                child->info = newinfo;
                /*
                 * Prepare for immediate synchronization with udev and flush all stacked
                 * dev node operations if requested by immediate_dev_node property. But
                 * finish processing current level in the tree first.
                 */
                if (child->props.immediate_dev_node)
                        update_devs_flag = 1;
        }

        if (update_devs_flag ||
            (!dnode->info.exists && dnode->callback)) {
                if (!dm_udev_wait(dm_tree_get_cookie(dnode)))
                        stack;
                dm_tree_set_cookie(dnode, 0);

                if (!dnode->info.exists && dnode->callback &&
                    !dnode->callback(child, DM_NODE_CALLBACK_PRELOADED,
                                     dnode->callback_data))
                        return_0;
        }

        return r;
}

/*
 * Returns 1 if unsure.
 */
int dm_tree_children_use_uuid(struct dm_tree_node *dnode,
                                 const char *uuid_prefix,
                                 size_t uuid_prefix_len)
{
        void *handle = NULL;
        struct dm_tree_node *child = dnode;
        const char *uuid;

        while ((child = dm_tree_next_child(&handle, dnode, 0))) {
                if (!(uuid = dm_tree_node_get_uuid(child))) {
                        log_error("Failed to get uuid for dtree node.");
                        return 1;
                }

                if (_uuid_prefix_matches(uuid, uuid_prefix, uuid_prefix_len))
                        return 1;

                if (dm_tree_node_num_children(child, 0))
                        dm_tree_children_use_uuid(child, uuid_prefix, uuid_prefix_len);
        }

        return 0;
}

/*
 * Target functions
 */
static struct load_segment *_add_segment(struct dm_tree_node *dnode, unsigned type, uint64_t size)
{
        struct load_segment *seg;

        if (!(seg = dm_pool_zalloc(dnode->dtree->mem, sizeof(*seg)))) {
                log_error("dtree node segment allocation failed");
                return NULL;
        }

        seg->type = type;
        seg->size = size;
        seg->area_count = 0;
        dm_list_init(&seg->areas);
        seg->stripe_size = 0;
        seg->persistent = 0;
        seg->chunk_size = 0;
        seg->cow = NULL;
        seg->origin = NULL;
        seg->merge = NULL;

        dm_list_add(&dnode->props.segs, &seg->list);
        dnode->props.segment_count++;

        return seg;
}

int dm_tree_node_add_snapshot_origin_target(struct dm_tree_node *dnode,
                                               uint64_t size,
                                               const char *origin_uuid)
{
        struct load_segment *seg;
        struct dm_tree_node *origin_node;

        if (!(seg = _add_segment(dnode, SEG_SNAPSHOT_ORIGIN, size)))
                return_0;

        if (!(origin_node = dm_tree_find_node_by_uuid(dnode->dtree, origin_uuid))) {
                log_error("Couldn't find snapshot origin uuid %s.", origin_uuid);
                return 0;
        }

        seg->origin = origin_node;
        if (!_link_tree_nodes(dnode, origin_node))
                return_0;

        /* Resume snapshot origins after new snapshots */
        dnode->activation_priority = 1;

        /*
         * Don't resume the origin immediately in case it is a non-trivial 
         * target that must not be active more than once concurrently!
         */
        origin_node->props.delay_resume_if_new = 1;

        return 1;
}

static int _add_snapshot_target(struct dm_tree_node *node,
                                   uint64_t size,
                                   const char *origin_uuid,
                                   const char *cow_uuid,
                                   const char *merge_uuid,
                                   int persistent,
                                   uint32_t chunk_size)
{
        struct load_segment *seg;
        struct dm_tree_node *origin_node, *cow_node, *merge_node;
        unsigned seg_type;

        seg_type = !merge_uuid ? SEG_SNAPSHOT : SEG_SNAPSHOT_MERGE;

        if (!(seg = _add_segment(node, seg_type, size)))
                return_0;

        if (!(origin_node = dm_tree_find_node_by_uuid(node->dtree, origin_uuid))) {
                log_error("Couldn't find snapshot origin uuid %s.", origin_uuid);
                return 0;
        }

        seg->origin = origin_node;
        if (!_link_tree_nodes(node, origin_node))
                return_0;

        if (!(cow_node = dm_tree_find_node_by_uuid(node->dtree, cow_uuid))) {
                log_error("Couldn't find snapshot COW device uuid %s.", cow_uuid);
                return 0;
        }

        seg->cow = cow_node;
        if (!_link_tree_nodes(node, cow_node))
                return_0;

        seg->persistent = persistent ? 1 : 0;
        seg->chunk_size = chunk_size;

        if (merge_uuid) {
                if (!(merge_node = dm_tree_find_node_by_uuid(node->dtree, merge_uuid))) {
                        /* not a pure error, merging snapshot may have been deactivated */
                        log_verbose("Couldn't find merging snapshot uuid %s.", merge_uuid);
                } else {
                        seg->merge = merge_node;
                        /* must not link merging snapshot, would undermine activation_priority below */
                }

                /* Resume snapshot-merge (acting origin) after other snapshots */
                node->activation_priority = 1;
                if (seg->merge) {
                        /* Resume merging snapshot after snapshot-merge */
                        seg->merge->activation_priority = 2;
                }
        }

        return 1;
}


int dm_tree_node_add_snapshot_target(struct dm_tree_node *node,
                                     uint64_t size,
                                     const char *origin_uuid,
                                     const char *cow_uuid,
                                     int persistent,
                                     uint32_t chunk_size)
{
        return _add_snapshot_target(node, size, origin_uuid, cow_uuid,
                                    NULL, persistent, chunk_size);
}

int dm_tree_node_add_snapshot_merge_target(struct dm_tree_node *node,
                                           uint64_t size,
                                           const char *origin_uuid,
                                           const char *cow_uuid,
                                           const char *merge_uuid,
                                           uint32_t chunk_size)
{
        return _add_snapshot_target(node, size, origin_uuid, cow_uuid,
                                    merge_uuid, 1, chunk_size);
}

int dm_tree_node_add_error_target(struct dm_tree_node *node,
                                     uint64_t size)
{
        if (!_add_segment(node, SEG_ERROR, size))
                return_0;

        return 1;
}

int dm_tree_node_add_zero_target(struct dm_tree_node *node,
                                    uint64_t size)
{
        if (!_add_segment(node, SEG_ZERO, size))
                return_0;

        return 1;
}

int dm_tree_node_add_linear_target(struct dm_tree_node *node,
                                      uint64_t size)
{
        if (!_add_segment(node, SEG_LINEAR, size))
                return_0;

        return 1;
}

int dm_tree_node_add_striped_target(struct dm_tree_node *node,
                                       uint64_t size,
                                       uint32_t stripe_size)
{
        struct load_segment *seg;

        if (!(seg = _add_segment(node, SEG_STRIPED, size)))
                return_0;

        seg->stripe_size = stripe_size;

        return 1;
}

int dm_tree_node_add_crypt_target(struct dm_tree_node *node,
                                  uint64_t size,
                                  const char *cipher,
                                  const char *chainmode,
                                  const char *iv,
                                  uint64_t iv_offset,
                                  const char *key)
{
        struct load_segment *seg;

        if (!(seg = _add_segment(node, SEG_CRYPT, size)))
                return_0;

        seg->cipher = cipher;
        seg->chainmode = chainmode;
        seg->iv = iv;
        seg->iv_offset = iv_offset;
        seg->key = key;

        return 1;
}

int dm_tree_node_add_mirror_target_log(struct dm_tree_node *node,
                                          uint32_t region_size,
                                          unsigned clustered,
                                          const char *log_uuid,
                                          unsigned area_count,
                                          uint32_t flags)
{
        struct dm_tree_node *log_node = NULL;
        struct load_segment *seg;

        if (!node->props.segment_count) {
                log_error(INTERNAL_ERROR "Attempt to add target area to missing segment.");
                return 0;
        }

        seg = dm_list_item(dm_list_last(&node->props.segs), struct load_segment);

        if (log_uuid) {
                if (!(seg->uuid = dm_pool_strdup(node->dtree->mem, log_uuid))) {
                        log_error("log uuid pool_strdup failed");
                        return 0;
                }
                if ((flags & DM_CORELOG))
                        /* For pvmove: immediate resume (for size validation) isn't needed. */
                        node->props.delay_resume_if_new = 1;
                else {
                        if (!(log_node = dm_tree_find_node_by_uuid(node->dtree, log_uuid))) {
                                log_error("Couldn't find mirror log uuid %s.", log_uuid);
                                return 0;
                        }

                        if (clustered)
                                log_node->props.immediate_dev_node = 1;

                        /* The kernel validates the size of disk logs. */
                        /* FIXME Propagate to any devices below */
                        log_node->props.delay_resume_if_new = 0;

                        if (!_link_tree_nodes(node, log_node))
                                return_0;
                }
        }

        seg->log = log_node;
        seg->region_size = region_size;
        seg->clustered = clustered;
        seg->mirror_area_count = area_count;
        seg->flags = flags;

        return 1;
}

int dm_tree_node_add_mirror_target(struct dm_tree_node *node,
                                      uint64_t size)
{
        if (!_add_segment(node, SEG_MIRRORED, size))
                return_0;

        return 1;
}

int dm_tree_node_add_raid_target(struct dm_tree_node *node,
                                 uint64_t size,
                                 const char *raid_type,
                                 uint32_t region_size,
                                 uint32_t stripe_size,
                                 uint64_t rebuilds,
                                 uint64_t flags)
{
        int i;
        struct load_segment *seg = NULL;

        for (i = 0; dm_segtypes[i].target && !seg; i++)
                if (!strcmp(raid_type, dm_segtypes[i].target))
                        if (!(seg = _add_segment(node,
                                                 dm_segtypes[i].type, size)))
                                return_0;

        if (!seg)
                return_0;

        seg->region_size = region_size;
        seg->stripe_size = stripe_size;
        seg->area_count = 0;
        seg->rebuilds = rebuilds;
        seg->flags = flags;

        return 1;
}

int dm_tree_node_add_replicator_target(struct dm_tree_node *node,
                                       uint64_t size,
                                       const char *rlog_uuid,
                                       const char *rlog_type,
                                       unsigned rsite_index,
                                       dm_replicator_mode_t mode,
                                       uint32_t async_timeout,
                                       uint64_t fall_behind_data,
                                       uint32_t fall_behind_ios)
{
        struct load_segment *rseg;
        struct replicator_site *rsite;

        /* Local site0 - adds replicator segment and links rlog device */
        if (rsite_index == REPLICATOR_LOCAL_SITE) {
                if (node->props.segment_count) {
                        log_error(INTERNAL_ERROR "Attempt to add replicator segment to already used node.");
                        return 0;
                }

                if (!(rseg = _add_segment(node, SEG_REPLICATOR, size)))
                        return_0;

                if (!(rseg->log = dm_tree_find_node_by_uuid(node->dtree, rlog_uuid))) {
                        log_error("Missing replicator log uuid %s.", rlog_uuid);
                        return 0;
                }

                if (!_link_tree_nodes(node, rseg->log))
                        return_0;

                if (strcmp(rlog_type, "ringbuffer") != 0) {
                        log_error("Unsupported replicator log type %s.", rlog_type);
                        return 0;
                }

                if (!(rseg->rlog_type = dm_pool_strdup(node->dtree->mem, rlog_type)))
                        return_0;

                dm_list_init(&rseg->rsites);
                rseg->rdevice_count = 0;
                node->activation_priority = 1;
        }

        /* Add site to segment */
        if (mode == DM_REPLICATOR_SYNC
            && (async_timeout || fall_behind_ios || fall_behind_data)) {
                log_error("Async parameters passed for synchronnous replicator.");
                return 0;
        }

        if (node->props.segment_count != 1) {
                log_error(INTERNAL_ERROR "Attempt to add remote site area before setting replicator log.");
                return 0;
        }

        rseg = dm_list_item(dm_list_last(&node->props.segs), struct load_segment);
        if (rseg->type != SEG_REPLICATOR) {
                log_error(INTERNAL_ERROR "Attempt to use non replicator segment %s.",
                          dm_segtypes[rseg->type].target);
                return 0;
        }

        if (!(rsite = dm_pool_zalloc(node->dtree->mem, sizeof(*rsite)))) {
                log_error("Failed to allocate remote site segment.");
                return 0;
        }

        dm_list_add(&rseg->rsites, &rsite->list);
        rseg->rsite_count++;

        rsite->mode = mode;
        rsite->async_timeout = async_timeout;
        rsite->fall_behind_data = fall_behind_data;
        rsite->fall_behind_ios = fall_behind_ios;
        rsite->rsite_index = rsite_index;

        return 1;
}

/* Appends device node to Replicator */
int dm_tree_node_add_replicator_dev_target(struct dm_tree_node *node,
                                           uint64_t size,
                                           const char *replicator_uuid,
                                           uint64_t rdevice_index,
                                           const char *rdev_uuid,
                                           unsigned rsite_index,
                                           const char *slog_uuid,
                                           uint32_t slog_flags,
                                           uint32_t slog_region_size)
{
        struct seg_area *area;
        struct load_segment *rseg;
        struct load_segment *rep_seg;

        if (rsite_index == REPLICATOR_LOCAL_SITE) {
                /* Site index for local target */
                if (!(rseg = _add_segment(node, SEG_REPLICATOR_DEV, size)))
                        return_0;

                if (!(rseg->replicator = dm_tree_find_node_by_uuid(node->dtree, replicator_uuid))) {
                        log_error("Missing replicator uuid %s.", replicator_uuid);
                        return 0;
                }

                /* Local slink0 for replicator must be always initialized first */
                if (rseg->replicator->props.segment_count != 1) {
                        log_error(INTERNAL_ERROR "Attempt to use non replicator segment.");
                        return 0;
                }

                rep_seg = dm_list_item(dm_list_last(&rseg->replicator->props.segs), struct load_segment);
                if (rep_seg->type != SEG_REPLICATOR) {
                        log_error(INTERNAL_ERROR "Attempt to use non replicator segment %s.",
                                  dm_segtypes[rep_seg->type].target);
                        return 0;
                }
                rep_seg->rdevice_count++;

                if (!_link_tree_nodes(node, rseg->replicator))
                        return_0;

                rseg->rdevice_index = rdevice_index;
        } else {
                /* Local slink0 for replicator must be always initialized first */
                if (node->props.segment_count != 1) {
                        log_error(INTERNAL_ERROR "Attempt to use non replicator-dev segment.");
                        return 0;
                }

                rseg = dm_list_item(dm_list_last(&node->props.segs), struct load_segment);
                if (rseg->type != SEG_REPLICATOR_DEV) {
                        log_error(INTERNAL_ERROR "Attempt to use non replicator-dev segment %s.",
                                  dm_segtypes[rseg->type].target);
                        return 0;
                }
        }

        if (!(slog_flags & DM_CORELOG) && !slog_uuid) {
                log_error("Unspecified sync log uuid.");
                return 0;
        }

        if (!dm_tree_node_add_target_area(node, NULL, rdev_uuid, 0))
                return_0;

        area = dm_list_item(dm_list_last(&rseg->areas), struct seg_area);

        if (!(slog_flags & DM_CORELOG)) {
                if (!(area->slog = dm_tree_find_node_by_uuid(node->dtree, slog_uuid))) {
                        log_error("Couldn't find sync log uuid %s.", slog_uuid);
                        return 0;
                }

                if (!_link_tree_nodes(node, area->slog))
                        return_0;
        }

        area->flags = slog_flags;
        area->region_size = slog_region_size;
        area->rsite_index = rsite_index;

        return 1;
}

static int _thin_validate_device_id(uint32_t device_id)
{
        if (device_id > DM_THIN_MAX_DEVICE_ID) {
                log_error("Device id %u is higher then %u.",
                          device_id, DM_THIN_MAX_DEVICE_ID);
                return 0;
        }

        return 1;
}

int dm_tree_node_add_thin_pool_target(struct dm_tree_node *node,
                                      uint64_t size,
                                      uint64_t transaction_id,
                                      const char *metadata_uuid,
                                      const char *pool_uuid,
                                      uint32_t data_block_size,
                                      uint64_t low_water_mark,
                                      unsigned skip_block_zeroing)
{
        struct load_segment *seg, *mseg;
        uint64_t devsize = 0;
        /*
         * Max supported size for thin pool  metadata device
         * Limitation is hardcoded into kernel and bigger
         * device size is not accepted. (16978542592)
         */
        const uint64_t max_metadata_size =
                255ULL * (1 << 14) * (4096 / (1 << 9)) - 256 * 1024;

        if (data_block_size < DM_THIN_MIN_DATA_BLOCK_SIZE) {
                log_error("Data block size %u is lower then %u sectors.",
                          data_block_size, DM_THIN_MIN_DATA_BLOCK_SIZE);
                return 0;
        }

        if (data_block_size > DM_THIN_MAX_DATA_BLOCK_SIZE) {
                log_error("Data block size %u is higher then %u sectors.",
                          data_block_size, DM_THIN_MAX_DATA_BLOCK_SIZE);
                return 0;
        }

        if (!(seg = _add_segment(node, SEG_THIN_POOL, size)))
                return_0;

        if (!(seg->metadata = dm_tree_find_node_by_uuid(node->dtree, metadata_uuid))) {
                log_error("Missing metadata uuid %s.", metadata_uuid);
                return 0;
        }

        if (!_link_tree_nodes(node, seg->metadata))
                return_0;

        /* FIXME: more complex target may need more tweaks */
        dm_list_iterate_items(mseg, &seg->metadata->props.segs) {
                devsize += mseg->size;
                if (devsize > max_metadata_size) {
                        log_debug("Ignoring %" PRIu64 " of device.",
                                  devsize - max_metadata_size);
                        mseg->size -= (devsize - max_metadata_size);
                        devsize = max_metadata_size;
                        /* FIXME: drop remaining segs */
                }
        }

        if (!(seg->pool = dm_tree_find_node_by_uuid(node->dtree, pool_uuid))) {
                log_error("Missing pool uuid %s.", pool_uuid);
                return 0;
        }

        if (!_link_tree_nodes(node, seg->pool))
                return_0;

        node->props.send_messages = 1;
        seg->transaction_id = transaction_id;
        seg->low_water_mark = low_water_mark;
        seg->data_block_size = data_block_size;
        seg->skip_block_zeroing = skip_block_zeroing;
        dm_list_init(&seg->thin_messages);

        return 1;
}

int dm_tree_node_add_thin_pool_message(struct dm_tree_node *node,
                                       dm_thin_message_t type,
                                       uint64_t id1, uint64_t id2)
{
        struct load_segment *seg;
        struct thin_message *tm;

        if (node->props.segment_count != 1) {
                log_error("Thin pool node must have only one segment.");
                return 0;
        }

        seg = dm_list_item(dm_list_last(&node->props.segs), struct load_segment);
        if (seg->type != SEG_THIN_POOL) {
                log_error("Thin pool node has segment type %s.",
                          dm_segtypes[seg->type].target);
                return 0;
        }

        if (!(tm = dm_pool_zalloc(node->dtree->mem, sizeof (*tm)))) {
                log_error("Failed to allocate thin message.");
                return 0;
        }

        switch (type) {
        case DM_THIN_MESSAGE_CREATE_SNAP:
                /* If the thin origin is active, it must be suspend first! */
                if (id1 == id2) {
                        log_error("Cannot use same device id for origin and its snapshot.");
                        return 0;
                }
                if (!_thin_validate_device_id(id1) ||
                    !_thin_validate_device_id(id2))
                        return_0;
                tm->message.u.m_create_snap.device_id = id1;
                tm->message.u.m_create_snap.origin_id = id2;
                break;
        case DM_THIN_MESSAGE_CREATE_THIN:
                if (!_thin_validate_device_id(id1))
                        return_0;
                tm->message.u.m_create_thin.device_id = id1;
                tm->expected_errno = EEXIST;
                break;
        case DM_THIN_MESSAGE_DELETE:
                if (!_thin_validate_device_id(id1))
                        return_0;
                tm->message.u.m_delete.device_id = id1;
                tm->expected_errno = ENODATA;
                break;
        case DM_THIN_MESSAGE_SET_TRANSACTION_ID:
                if ((id1 + 1) != id2) {
                        log_error("New transaction id must be sequential.");
                        return 0; /* FIXME: Maybe too strict here? */
                }
                if (id2 != seg->transaction_id) {
                        log_error("Current transaction id is different from thin pool.");
                        return 0; /* FIXME: Maybe too strict here? */
                }
                tm->message.u.m_set_transaction_id.current_id = id1;
                tm->message.u.m_set_transaction_id.new_id = id2;
                break;
        default:
                log_error("Unsupported message type %d.", (int) type);
                return 0;
        }

        tm->message.type = type;
        dm_list_add(&seg->thin_messages, &tm->list);

        return 1;
}

int dm_tree_node_add_thin_target(struct dm_tree_node *node,
                                 uint64_t size,
                                 const char *pool_uuid,
                                 uint32_t device_id)
{
        struct dm_tree_node *pool;
        struct load_segment *seg;

        if (!(pool = dm_tree_find_node_by_uuid(node->dtree, pool_uuid))) {
                log_error("Missing thin pool uuid %s.", pool_uuid);
                return 0;
        }

        if (!_link_tree_nodes(node, pool))
                return_0;

        if (!_thin_validate_device_id(device_id))
                return_0;

        if (!(seg = _add_segment(node, SEG_THIN, size)))
                return_0;

        seg->pool = pool;
        seg->device_id = device_id;

        return 1;
}


int dm_get_status_thin_pool(struct dm_pool *mem, const char *params,
                            struct dm_status_thin_pool **status)
{
        struct dm_status_thin_pool *s;

        if (!(s = dm_pool_zalloc(mem, sizeof(struct dm_status_thin_pool)))) {
                log_error("Failed to allocate thin_pool status structure.");
                return 0;
        }

        /* FIXME: add support for held metadata root */
        if (sscanf(params, "%" PRIu64 " %" PRIu64 "/%" PRIu64 " %" PRIu64 "/%" PRIu64,
                   &s->transaction_id,
                   &s->used_metadata_blocks,
                   &s->total_metadata_blocks,
                   &s->used_data_blocks,
                   &s->total_data_blocks) != 5) {
                log_error("Failed to parse thin pool params: %s.", params);
                return 0;
        }

        *status = s;

        return 1;
}

int dm_get_status_thin(struct dm_pool *mem, const char *params,
                       struct dm_status_thin **status)
{
        struct dm_status_thin *s;

        if (!(s = dm_pool_zalloc(mem, sizeof(struct dm_status_thin)))) {
                log_error("Failed to allocate thin status structure.");
                return 0;
        }

        if (strchr(params, '-')) {
                s->mapped_sectors = 0;
                s->highest_mapped_sector = 0;
        } else if (sscanf(params, "%" PRIu64 " %" PRIu64,
                   &s->mapped_sectors,
                   &s->highest_mapped_sector) != 2) {
                log_error("Failed to parse thin params: %s.", params);
                return 0;
        }

        *status = s;

        return 1;
}

static int _add_area(struct dm_tree_node *node, struct load_segment *seg, struct dm_tree_node *dev_node, uint64_t offset)
{
        struct seg_area *area;

        if (!(area = dm_pool_zalloc(node->dtree->mem, sizeof (*area)))) {
                log_error("Failed to allocate target segment area.");
                return 0;
        }

        area->dev_node = dev_node;
        area->offset = offset;

        dm_list_add(&seg->areas, &area->list);
        seg->area_count++;

        return 1;
}

int dm_tree_node_add_target_area(struct dm_tree_node *node,
                                    const char *dev_name,
                                    const char *uuid,
                                    uint64_t offset)
{
        struct load_segment *seg;
        struct stat info;
        struct dm_tree_node *dev_node;

        if ((!dev_name || !*dev_name) && (!uuid || !*uuid)) {
                log_error("dm_tree_node_add_target_area called without device");
                return 0;
        }

        if (uuid) {
                if (!(dev_node = dm_tree_find_node_by_uuid(node->dtree, uuid))) {
                        log_error("Couldn't find area uuid %s.", uuid);
                        return 0;
                }
                if (!_link_tree_nodes(node, dev_node))
                        return_0;
        } else {
                if (stat(dev_name, &info) < 0) {
                        log_error("Device %s not found.", dev_name);
                        return 0;
                }

                if (!S_ISBLK(info.st_mode)) {
                        log_error("Device %s is not a block device.", dev_name);
                        return 0;
                }

                /* FIXME Check correct macro use */
                if (!(dev_node = _add_dev(node->dtree, node, MAJOR(info.st_rdev),
                                          MINOR(info.st_rdev), 0)))
                        return_0;
        }

        if (!node->props.segment_count) {
                log_error(INTERNAL_ERROR "Attempt to add target area to missing segment.");
                return 0;
        }

        seg = dm_list_item(dm_list_last(&node->props.segs), struct load_segment);

        if (!_add_area(node, seg, dev_node, offset))
                return_0;

        return 1;
}

int dm_tree_node_add_null_area(struct dm_tree_node *node, uint64_t offset)
{
        struct load_segment *seg;

        seg = dm_list_item(dm_list_last(&node->props.segs), struct load_segment);

        switch (seg->type) {
        case SEG_RAID1:
        case SEG_RAID4:
        case SEG_RAID5_LA:
        case SEG_RAID5_RA:
        case SEG_RAID5_LS:
        case SEG_RAID5_RS:
        case SEG_RAID6_ZR:
        case SEG_RAID6_NR:
        case SEG_RAID6_NC:
                break;
        default:
                log_error("dm_tree_node_add_null_area() called on an unsupported segment type");
                return 0;
        }

        if (!_add_area(node, seg, NULL, offset))
                return_0;

        return 1;
}

void dm_tree_node_set_callback(struct dm_tree_node *dnode,
                               dm_node_callback_fn cb, void *data)
{
        dnode->callback = cb;
        dnode->callback_data = data;
}