lvm2/libdm/libdm-deptree.c

/*
 * Copyright (C) 2005-2007 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 "lib.h"
#include "libdm-targets.h"
#include "libdm-common.h"
#include "list.h"
#include "kdev_t.h"
#include "dm-ioctl.h"

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

#define MAX_TARGET_PARAMSIZE 500000

/* FIXME Fix interface so this is used only by LVM */
#define UUID_PREFIX "LVM-"

/* Supported segment types */
enum {
	SEG_ERROR, 
	SEG_LINEAR,
	SEG_MIRRORED,
	SEG_SNAPSHOT,
	SEG_SNAPSHOT_ORIGIN,
	SEG_STRIPED,
	SEG_ZERO,
};

/* FIXME Add crypt and multipath support */

struct {
	unsigned type;
	const char *target;
} dm_segtypes[] = {
	{ SEG_ERROR, "error" },
	{ SEG_LINEAR, "linear" },
	{ SEG_MIRRORED, "mirror" },
	{ SEG_SNAPSHOT, "snapshot" },
	{ SEG_SNAPSHOT_ORIGIN, "snapshot-origin" },
	{ SEG_STRIPED, "striped" },
	{ SEG_ZERO, "zero"},
};

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

	struct dm_tree_node *dev_node;

	uint64_t offset;
};

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

	unsigned type;

	uint64_t size;

	unsigned area_count;		/* Linear + Striped + Mirrored */
	struct list areas;		/* Linear + Striped + Mirrored */

	uint32_t stripe_size;		/* Striped */

	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 *log;	/* Mirror */
	uint32_t region_size;		/* Mirror */
	unsigned clustered;		/* Mirror */
	unsigned mirror_area_count;	/* Mirror */
	uint32_t flags;			/* Mirror log */
	char *uuid;			/* Clustered mirror log */
};

/* 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 list segs;

	const char *new_name;
};

/* Two of these used to join two nodes with uses and used_by. */
struct dm_tree_link {
	struct 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 list uses;       	/* Nodes this node uses */
        struct list used_by;    	/* Nodes that use this node */

	int activation_priority;	/* 0 gets activated first */

	void *context;			/* External supplied context */

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

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) */
};

/* FIXME Consider exporting this */
static int _dm_snprintf(char *buf, size_t bufsize, const char *format, ...)
{
        int n;
        va_list ap;

        va_start(ap, format);
        n = vsnprintf(buf, bufsize, format, ap);
        va_end(ap);

        if (n < 0 || (n > (int) bufsize - 1))
                return -1;

        return n;
}

struct dm_tree *dm_tree_create(void)
{
	struct dm_tree *dtree;

	if (!(dtree = dm_malloc(sizeof(*dtree)))) {
		log_error("dm_tree_create malloc failed");
		return NULL;
	}

	memset(dtree, 0, sizeof(*dtree));
	dtree->root.dtree = dtree;
	list_init(&dtree->root.uses);
	list_init(&dtree->root.used_by);
	dtree->skip_lockfs = 0;
	dtree->no_flush = 0;

	if (!(dtree->mem = dm_pool_create("dtree", 1024))) {
		log_error("dtree pool creation failed");
		dm_free(dtree);
		return NULL;
	}

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

static int _nodes_are_linked(struct dm_tree_node *parent,
			     struct dm_tree_node *child)
{
	struct dm_tree_link *dlink;

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

	return 0;
}

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

	list_iterate_items(dlink, list)
		if (dlink->node == node) {
			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)
{
	return _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)
{
	return _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)
{
	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->activation_priority = 0;

	list_init(&node->uses);
	list_init(&node->used_by);
	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;

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

	if (strncmp(uuid, UUID_PREFIX, sizeof(UUID_PREFIX) - 1))
		return NULL;

	return dm_hash_lookup(dtree->uuids, uuid + sizeof(UUID_PREFIX) - 1);
}

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

	if (!dm_is_dm_major(major)) {
		*name = "";
		*uuid = "";
		*deps = NULL;
		info->major = major;
		info->minor = minor;
		info->exists = 0;
		info->live_table = 0;
		info->inactive_table = 0;
		info->read_only = 0;
		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 (!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) {
		*name = "";
		*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 = dm_pool_strdup(mem, dm_task_get_name(*dmt)))) {
			log_error("name pool_strdup failed");
			goto failed;
		}
		if (!(*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;
}

static struct dm_tree_node *_add_dev(struct dm_tree *dtree,
				     struct dm_tree_node *parent,
				     uint32_t major, uint32_t minor)
{
	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, &info, &deps))
			return_NULL;

		if (!(node = _create_dm_tree_node(dtree, name, uuid,
						  &info, NULL)))
			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->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]))) {
			node = NULL;
			goto_out;
		}

out:
	if (dmt)
		dm_task_destroy(dmt);

	return node;
}

static int _node_clear_table(struct dm_tree_node *dnode)
{
	struct dm_task *dmt;
	struct dm_info *info;
	const char *name;
	int r;

	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;

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

	if (!(dmt = dm_task_create(DM_DEVICE_CLEAR))) {
		dm_task_destroy(dmt);
		log_error("Table clear dm_task creation failed for %s", name);
		return 0;
	}

	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);
		dm_task_destroy(dmt);
		return 0;
	}

	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;
	}

	dm_task_destroy(dmt);

	return r;
}

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)
{
	struct dm_tree_node *dnode;
	struct dm_info info;
	const char *name2;
	const char *uuid2;

	/* 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;
		}

		info.major = 0;
		info.minor = 0;
		info.exists = 0;
		info.live_table = 0;
		info.inactive_table = 0;
		info.read_only = 0;

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

	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))
		return_NULL;

	dnode->context = context;

	return dnode;
}

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;
}

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

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

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

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

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

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

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

	return 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)
{
	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, UUID_PREFIX, sizeof(UUID_PREFIX) - 1))
		return 0;

	if (strncmp(uuid_prefix, UUID_PREFIX, sizeof(UUID_PREFIX) - 1))
		return 0;

	if (!strncmp(uuid, uuid_prefix + sizeof(UUID_PREFIX) - 1, uuid_prefix_len - (sizeof(UUID_PREFIX) - 1)))
		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 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;
	}

	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;

		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,
					   struct dm_tree_node *parent,
					   uint32_t inverted)
{
	struct list **dlink = (struct list **) handle;
	struct list *use_list;

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

	if (!*dlink)
		*dlink =