dm-ioctl.c 34.9 KB
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/*
 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
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 * Copyright (C) 2004 - 2006 Red Hat, Inc. All rights reserved.
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 *
 * This file is released under the GPL.
 */

#include "dm.h"

#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/miscdevice.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <linux/dm-ioctl.h>
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#include <linux/hdreg.h>
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#include <linux/compat.h>
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#include <asm/uaccess.h>

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#define DM_MSG_PREFIX "ioctl"
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#define DM_DRIVER_EMAIL "dm-devel@redhat.com"

/*-----------------------------------------------------------------
 * The ioctl interface needs to be able to look up devices by
 * name or uuid.
 *---------------------------------------------------------------*/
struct hash_cell {
	struct list_head name_list;
	struct list_head uuid_list;

	char *name;
	char *uuid;
	struct mapped_device *md;
	struct dm_table *new_map;
};

struct vers_iter {
    size_t param_size;
    struct dm_target_versions *vers, *old_vers;
    char *end;
    uint32_t flags;
};


#define NUM_BUCKETS 64
#define MASK_BUCKETS (NUM_BUCKETS - 1)
static struct list_head _name_buckets[NUM_BUCKETS];
static struct list_head _uuid_buckets[NUM_BUCKETS];

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static void dm_hash_remove_all(int keep_open_devices);
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/*
 * Guards access to both hash tables.
 */
static DECLARE_RWSEM(_hash_lock);

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/*
 * Protects use of mdptr to obtain hash cell name and uuid from mapped device.
 */
static DEFINE_MUTEX(dm_hash_cells_mutex);

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static void init_buckets(struct list_head *buckets)
{
	unsigned int i;

	for (i = 0; i < NUM_BUCKETS; i++)
		INIT_LIST_HEAD(buckets + i);
}

static int dm_hash_init(void)
{
	init_buckets(_name_buckets);
	init_buckets(_uuid_buckets);
	return 0;
}

static void dm_hash_exit(void)
{
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	dm_hash_remove_all(0);
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}

/*-----------------------------------------------------------------
 * Hash function:
 * We're not really concerned with the str hash function being
 * fast since it's only used by the ioctl interface.
 *---------------------------------------------------------------*/
static unsigned int hash_str(const char *str)
{
	const unsigned int hash_mult = 2654435387U;
	unsigned int h = 0;

	while (*str)
		h = (h + (unsigned int) *str++) * hash_mult;

	return h & MASK_BUCKETS;
}

/*-----------------------------------------------------------------
 * Code for looking up a device by name
 *---------------------------------------------------------------*/
static struct hash_cell *__get_name_cell(const char *str)
{
	struct hash_cell *hc;
	unsigned int h = hash_str(str);

	list_for_each_entry (hc, _name_buckets + h, name_list)
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		if (!strcmp(hc->name, str)) {
			dm_get(hc->md);
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			return hc;
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		}
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	return NULL;
}

static struct hash_cell *__get_uuid_cell(const char *str)
{
	struct hash_cell *hc;
	unsigned int h = hash_str(str);

	list_for_each_entry (hc, _uuid_buckets + h, uuid_list)
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		if (!strcmp(hc->uuid, str)) {
			dm_get(hc->md);
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			return hc;
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		}
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	return NULL;
}

/*-----------------------------------------------------------------
 * Inserting, removing and renaming a device.
 *---------------------------------------------------------------*/
static struct hash_cell *alloc_cell(const char *name, const char *uuid,
				    struct mapped_device *md)
{
	struct hash_cell *hc;

	hc = kmalloc(sizeof(*hc), GFP_KERNEL);
	if (!hc)
		return NULL;

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	hc->name = kstrdup(name, GFP_KERNEL);
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	if (!hc->name) {
		kfree(hc);
		return NULL;
	}

	if (!uuid)
		hc->uuid = NULL;

	else {
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		hc->uuid = kstrdup(uuid, GFP_KERNEL);
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		if (!hc->uuid) {
			kfree(hc->name);
			kfree(hc);
			return NULL;
		}
	}

	INIT_LIST_HEAD(&hc->name_list);
	INIT_LIST_HEAD(&hc->uuid_list);
	hc->md = md;
	hc->new_map = NULL;
	return hc;
}

static void free_cell(struct hash_cell *hc)
{
	if (hc) {
		kfree(hc->name);
		kfree(hc->uuid);
		kfree(hc);
	}
}

/*
 * The kdev_t and uuid of a device can never change once it is
 * initially inserted.
 */
static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md)
{
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	struct hash_cell *cell, *hc;
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	/*
	 * Allocate the new cells.
	 */
	cell = alloc_cell(name, uuid, md);
	if (!cell)
		return -ENOMEM;

	/*
	 * Insert the cell into both hash tables.
	 */
	down_write(&_hash_lock);
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	hc = __get_name_cell(name);
	if (hc) {
		dm_put(hc->md);
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		goto bad;
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	}
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	list_add(&cell->name_list, _name_buckets + hash_str(name));

	if (uuid) {
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		hc = __get_uuid_cell(uuid);
		if (hc) {
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			list_del(&cell->name_list);
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			dm_put(hc->md);
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			goto bad;
		}
		list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
	}
	dm_get(md);
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	mutex_lock(&dm_hash_cells_mutex);
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	dm_set_mdptr(md, cell);
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	mutex_unlock(&dm_hash_cells_mutex);
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	up_write(&_hash_lock);

	return 0;

 bad:
	up_write(&_hash_lock);
	free_cell(cell);
	return -EBUSY;
}

static void __hash_remove(struct hash_cell *hc)
{
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	struct dm_table *table;

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	/* remove from the dev hash */
	list_del(&hc->uuid_list);
	list_del(&hc->name_list);
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	mutex_lock(&dm_hash_cells_mutex);
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	dm_set_mdptr(hc->md, NULL);
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	mutex_unlock(&dm_hash_cells_mutex);
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	table = dm_get_live_table(hc->md);
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	if (table) {
		dm_table_event(table);
		dm_table_put(table);
	}

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	if (hc->new_map)
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		dm_table_destroy(hc->new_map);
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	dm_put(hc->md);
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	free_cell(hc);
}

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static void dm_hash_remove_all(int keep_open_devices)
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{
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	int i, dev_skipped;
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	struct hash_cell *hc;
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	struct mapped_device *md;

retry:
	dev_skipped = 0;
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	down_write(&_hash_lock);
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	for (i = 0; i < NUM_BUCKETS; i++) {
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		list_for_each_entry(hc, _name_buckets + i, name_list) {
			md = hc->md;
			dm_get(md);
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			if (keep_open_devices && dm_lock_for_deletion(md)) {
				dm_put(md);
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				dev_skipped++;
				continue;
			}
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			__hash_remove(hc);
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			up_write(&_hash_lock);
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			dm_put(md);
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			if (likely(keep_open_devices))
				dm_destroy(md);
			else
				dm_destroy_immediate(md);
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			/*
			 * Some mapped devices may be using other mapped
			 * devices, so repeat until we make no further
			 * progress.  If a new mapped device is created
			 * here it will also get removed.
			 */
			goto retry;
		}
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	}

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	up_write(&_hash_lock);
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	if (dev_skipped)
		DMWARN("remove_all left %d open device(s)", dev_skipped);
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}

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static struct mapped_device *dm_hash_rename(struct dm_ioctl *param,
					    const char *new)
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{
	char *new_name, *old_name;
	struct hash_cell *hc;
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	struct dm_table *table;
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	struct mapped_device *md;
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	/*
	 * duplicate new.
	 */
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	new_name = kstrdup(new, GFP_KERNEL);
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	if (!new_name)
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		return ERR_PTR(-ENOMEM);
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	down_write(&_hash_lock);

	/*
	 * Is new free ?
	 */
	hc = __get_name_cell(new);
	if (hc) {
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		DMWARN("asked to rename to an already-existing name %s -> %s",
		       param->name, new);
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		dm_put(hc->md);
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		up_write(&_hash_lock);
		kfree(new_name);
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		return ERR_PTR(-EBUSY);
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	}

	/*
	 * Is there such a device as 'old' ?
	 */
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	hc = __get_name_cell(param->name);
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	if (!hc) {
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		DMWARN("asked to rename a non-existent device %s -> %s",
		       param->name, new);
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		up_write(&_hash_lock);
		kfree(new_name);
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		return ERR_PTR(-ENXIO);
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	}

	/*
	 * rename and move the name cell.
	 */
	list_del(&hc->name_list);
	old_name = hc->name;
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	mutex_lock(&dm_hash_cells_mutex);
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	hc->name = new_name;
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	mutex_unlock(&dm_hash_cells_mutex);
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	list_add(&hc->name_list, _name_buckets + hash_str(new_name));

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	/*
	 * Wake up any dm event waiters.
	 */
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	table = dm_get_live_table(hc->md);
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	if (table) {
		dm_table_event(table);
		dm_table_put(table);
	}

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	if (!dm_kobject_uevent(hc->md, KOBJ_CHANGE, param->event_nr))
		param->flags |= DM_UEVENT_GENERATED_FLAG;
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	md = hc->md;
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	up_write(&_hash_lock);
	kfree(old_name);
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	return md;
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}

/*-----------------------------------------------------------------
 * Implementation of the ioctl commands
 *---------------------------------------------------------------*/
/*
 * All the ioctl commands get dispatched to functions with this
 * prototype.
 */
typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);

static int remove_all(struct dm_ioctl *param, size_t param_size)
{
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	dm_hash_remove_all(1);
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	param->data_size = 0;
	return 0;
}

/*
 * Round up the ptr to an 8-byte boundary.
 */
#define ALIGN_MASK 7
static inline void *align_ptr(void *ptr)
{
	return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
}

/*
 * Retrieves the data payload buffer from an already allocated
 * struct dm_ioctl.
 */
static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
			       size_t *len)
{
	param->data_start = align_ptr(param + 1) - (void *) param;

	if (param->data_start < param_size)
		*len = param_size - param->data_start;
	else
		*len = 0;

	return ((void *) param) + param->data_start;
}

static int list_devices(struct dm_ioctl *param, size_t param_size)
{
	unsigned int i;
	struct hash_cell *hc;
	size_t len, needed = 0;
	struct gendisk *disk;
	struct dm_name_list *nl, *old_nl = NULL;

	down_write(&_hash_lock);

	/*
	 * Loop through all the devices working out how much
	 * space we need.
	 */
	for (i = 0; i < NUM_BUCKETS; i++) {
		list_for_each_entry (hc, _name_buckets + i, name_list) {
			needed += sizeof(struct dm_name_list);
			needed += strlen(hc->name) + 1;
			needed += ALIGN_MASK;
		}
	}

	/*
	 * Grab our output buffer.
	 */
	nl = get_result_buffer(param, param_size, &len);
	if (len < needed) {
		param->flags |= DM_BUFFER_FULL_FLAG;
		goto out;
	}
	param->data_size = param->data_start + needed;

	nl->dev = 0;	/* Flags no data */

	/*
	 * Now loop through filling out the names.
	 */
	for (i = 0; i < NUM_BUCKETS; i++) {
		list_for_each_entry (hc, _name_buckets + i, name_list) {
			if (old_nl)
				old_nl->next = (uint32_t) ((void *) nl -
							   (void *) old_nl);
			disk = dm_disk(hc->md);
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			nl->dev = huge_encode_dev(disk_devt(disk));
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			nl->next = 0;
			strcpy(nl->name, hc->name);

			old_nl = nl;
			nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
		}
	}

 out:
	up_write(&_hash_lock);
	return 0;
}

static void list_version_get_needed(struct target_type *tt, void *needed_param)
{
    size_t *needed = needed_param;

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    *needed += sizeof(struct dm_target_versions);
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    *needed += strlen(tt->name);
    *needed += ALIGN_MASK;
}

static void list_version_get_info(struct target_type *tt, void *param)
{
    struct vers_iter *info = param;

    /* Check space - it might have changed since the first iteration */
    if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
	info->end) {

	info->flags = DM_BUFFER_FULL_FLAG;
	return;
    }

    if (info->old_vers)
	info->old_vers->next = (uint32_t) ((void *)info->vers -
					   (void *)info->old_vers);
    info->vers->version[0] = tt->version[0];
    info->vers->version[1] = tt->version[1];
    info->vers->version[2] = tt->version[2];
    info->vers->next = 0;
    strcpy(info->vers->name, tt->name);

    info->old_vers = info->vers;
    info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
}

static int list_versions(struct dm_ioctl *param, size_t param_size)
{
	size_t len, needed = 0;
	struct dm_target_versions *vers;
	struct vers_iter iter_info;

	/*
	 * Loop through all the devices working out how much
	 * space we need.
	 */
	dm_target_iterate(list_version_get_needed, &needed);

	/*
	 * Grab our output buffer.
	 */
	vers = get_result_buffer(param, param_size, &len);
	if (len < needed) {
		param->flags |= DM_BUFFER_FULL_FLAG;
		goto out;
	}
	param->data_size = param->data_start + needed;

	iter_info.param_size = param_size;
	iter_info.old_vers = NULL;
	iter_info.vers = vers;
	iter_info.flags = 0;
	iter_info.end = (char *)vers+len;

	/*
	 * Now loop through filling out the names & versions.
	 */
	dm_target_iterate(list_version_get_info, &iter_info);
	param->flags |= iter_info.flags;

 out:
	return 0;
}

static int check_name(const char *name)
{
	if (strchr(name, '/')) {
		DMWARN("invalid device name");
		return -EINVAL;
	}

	return 0;
}

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/*
 * On successful return, the caller must not attempt to acquire
 * _hash_lock without first calling dm_table_put, because dm_table_destroy
 * waits for this dm_table_put and could be called under this lock.
 */
static struct dm_table *dm_get_inactive_table(struct mapped_device *md)
{
	struct hash_cell *hc;
	struct dm_table *table = NULL;

	down_read(&_hash_lock);
	hc = dm_get_mdptr(md);
	if (!hc || hc->md != md) {
		DMWARN("device has been removed from the dev hash table.");
		goto out;
	}

	table = hc->new_map;
	if (table)
		dm_table_get(table);

out:
	up_read(&_hash_lock);

	return table;
}

static struct dm_table *dm_get_live_or_inactive_table(struct mapped_device *md,
						      struct dm_ioctl *param)
{
	return (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) ?
		dm_get_inactive_table(md) : dm_get_live_table(md);
}

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/*
 * Fills in a dm_ioctl structure, ready for sending back to
 * userland.
 */
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static void __dev_status(struct mapped_device *md, struct dm_ioctl *param)
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{
	struct gendisk *disk = dm_disk(md);
	struct dm_table *table;

	param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
			  DM_ACTIVE_PRESENT_FLAG);

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	if (dm_suspended_md(md))
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		param->flags |= DM_SUSPEND_FLAG;

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	param->dev = huge_encode_dev(disk_devt(disk));
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	/*
	 * Yes, this will be out of date by the time it gets back
	 * to userland, but it is still very useful for
	 * debugging.
	 */
	param->open_count = dm_open_count(md);
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	param->event_nr = dm_get_event_nr(md);
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	param->target_count = 0;
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	table = dm_get_live_table(md);
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	if (table) {
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		if (!(param->flags & DM_QUERY_INACTIVE_TABLE_FLAG)) {
			if (get_disk_ro(disk))
				param->flags |= DM_READONLY_FLAG;
			param->target_count = dm_table_get_num_targets(table);
		}
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		dm_table_put(table);
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		param->flags |= DM_ACTIVE_PRESENT_FLAG;
	}

	if (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) {
		table = dm_get_inactive_table(md);
		if (table) {
			if (!(dm_table_get_mode(table) & FMODE_WRITE))
				param->flags |= DM_READONLY_FLAG;
			param->target_count = dm_table_get_num_targets(table);
			dm_table_put(table);
		}
	}
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}

static int dev_create(struct dm_ioctl *param, size_t param_size)
{
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	int r, m = DM_ANY_MINOR;
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	struct mapped_device *md;

	r = check_name(param->name);
	if (r)
		return r;

	if (param->flags & DM_PERSISTENT_DEV_FLAG)
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		m = MINOR(huge_decode_dev(param->dev));
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	r = dm_create(m, &md);
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	if (r)
		return r;

	r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
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	if (r) {
		dm_put(md);
		dm_destroy(md);
		return r;
	}
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	param->flags &= ~DM_INACTIVE_PRESENT_FLAG;

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	__dev_status(md, param);

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	dm_put(md);

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	return 0;
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}

/*
 * Always use UUID for lookups if it's present, otherwise use name or dev.
 */
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static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
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{
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	struct mapped_device *md;
	void *mdptr = NULL;

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	if (*param->uuid)
		return __get_uuid_cell(param->uuid);
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	if (*param->name)
L
Linus Torvalds 已提交
678
		return __get_name_cell(param->name);
A
Alasdair G Kergon 已提交
679 680

	md = dm_get_md(huge_decode_dev(param->dev));
681 682 683 684 685 686
	if (!md)
		goto out;

	mdptr = dm_get_mdptr(md);
	if (!mdptr)
		dm_put(md);
A
Alasdair G Kergon 已提交
687

688
out:
A
Alasdair G Kergon 已提交
689
	return mdptr;
L
Linus Torvalds 已提交
690 691
}

692
static struct mapped_device *find_device(struct dm_ioctl *param)
L
Linus Torvalds 已提交
693 694 695 696 697 698 699 700 701 702 703 704 705
{
	struct hash_cell *hc;
	struct mapped_device *md = NULL;

	down_read(&_hash_lock);
	hc = __find_device_hash_cell(param);
	if (hc) {
		md = hc->md;

		/*
		 * Sneakily write in both the name and the uuid
		 * while we have the cell.
		 */
R
Roel Kluin 已提交
706
		strlcpy(param->name, hc->name, sizeof(param->name));
L
Linus Torvalds 已提交
707
		if (hc->uuid)
R
Roel Kluin 已提交
708
			strlcpy(param->uuid, hc->uuid, sizeof(param->uuid));
L
Linus Torvalds 已提交
709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724
		else
			param->uuid[0] = '\0';

		if (hc->new_map)
			param->flags |= DM_INACTIVE_PRESENT_FLAG;
		else
			param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
	}
	up_read(&_hash_lock);

	return md;
}

static int dev_remove(struct dm_ioctl *param, size_t param_size)
{
	struct hash_cell *hc;
725
	struct mapped_device *md;
726
	int r;
L
Linus Torvalds 已提交
727 728 729 730 731 732 733 734 735 736

	down_write(&_hash_lock);
	hc = __find_device_hash_cell(param);

	if (!hc) {
		DMWARN("device doesn't appear to be in the dev hash table.");
		up_write(&_hash_lock);
		return -ENXIO;
	}

737 738
	md = hc->md;

739 740 741 742 743 744 745 746 747 748 749
	/*
	 * Ensure the device is not open and nothing further can open it.
	 */
	r = dm_lock_for_deletion(md);
	if (r) {
		DMWARN("unable to remove open device %s", hc->name);
		up_write(&_hash_lock);
		dm_put(md);
		return r;
	}

L
Linus Torvalds 已提交
750 751
	__hash_remove(hc);
	up_write(&_hash_lock);
M
Milan Broz 已提交
752

753 754
	if (!dm_kobject_uevent(md, KOBJ_REMOVE, param->event_nr))
		param->flags |= DM_UEVENT_GENERATED_FLAG;
M
Milan Broz 已提交
755

756
	dm_put(md);
757
	dm_destroy(md);
L
Linus Torvalds 已提交
758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777
	return 0;
}

/*
 * Check a string doesn't overrun the chunk of
 * memory we copied from userland.
 */
static int invalid_str(char *str, void *end)
{
	while ((void *) str < end)
		if (!*str++)
			return 0;

	return -EINVAL;
}

static int dev_rename(struct dm_ioctl *param, size_t param_size)
{
	int r;
	char *new_name = (char *) param + param->data_start;
778
	struct mapped_device *md;
L
Linus Torvalds 已提交
779

A
Alasdair G Kergon 已提交
780
	if (new_name < param->data ||
781 782
	    invalid_str(new_name, (void *) param + param_size) ||
	    strlen(new_name) > DM_NAME_LEN - 1) {
L
Linus Torvalds 已提交
783 784 785 786 787 788 789 790
		DMWARN("Invalid new logical volume name supplied.");
		return -EINVAL;
	}

	r = check_name(new_name);
	if (r)
		return r;

791 792 793
	md = dm_hash_rename(param, new_name);
	if (IS_ERR(md))
		return PTR_ERR(md);
794

795 796 797 798
	__dev_status(md, param);
	dm_put(md);

	return 0;
L
Linus Torvalds 已提交
799 800
}

D
Darrick J. Wong 已提交
801 802 803 804 805 806 807 808 809 810 811 812
static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
{
	int r = -EINVAL, x;
	struct mapped_device *md;
	struct hd_geometry geometry;
	unsigned long indata[4];
	char *geostr = (char *) param + param->data_start;

	md = find_device(param);
	if (!md)
		return -ENXIO;

A
Alasdair G Kergon 已提交
813
	if (geostr < param->data ||
D
Darrick J. Wong 已提交
814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846
	    invalid_str(geostr, (void *) param + param_size)) {
		DMWARN("Invalid geometry supplied.");
		goto out;
	}

	x = sscanf(geostr, "%lu %lu %lu %lu", indata,
		   indata + 1, indata + 2, indata + 3);

	if (x != 4) {
		DMWARN("Unable to interpret geometry settings.");
		goto out;
	}

	if (indata[0] > 65535 || indata[1] > 255 ||
	    indata[2] > 255 || indata[3] > ULONG_MAX) {
		DMWARN("Geometry exceeds range limits.");
		goto out;
	}

	geometry.cylinders = indata[0];
	geometry.heads = indata[1];
	geometry.sectors = indata[2];
	geometry.start = indata[3];

	r = dm_set_geometry(md, &geometry);

	param->data_size = 0;

out:
	dm_put(md);
	return r;
}

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Linus Torvalds 已提交
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static int do_suspend(struct dm_ioctl *param)
{
	int r = 0;
850
	unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
L
Linus Torvalds 已提交
851 852 853 854 855 856
	struct mapped_device *md;

	md = find_device(param);
	if (!md)
		return -ENXIO;

857
	if (param->flags & DM_SKIP_LOCKFS_FLAG)
858
		suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
859 860
	if (param->flags & DM_NOFLUSH_FLAG)
		suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
861

862
	if (!dm_suspended_md(md)) {
863
		r = dm_suspend(md, suspend_flags);
864 865 866
		if (r)
			goto out;
	}
L
Linus Torvalds 已提交
867

868
	__dev_status(md, param);
L
Linus Torvalds 已提交
869

870
out:
L
Linus Torvalds 已提交
871
	dm_put(md);
872

L
Linus Torvalds 已提交
873 874 875 876 877 878
	return r;
}

static int do_resume(struct dm_ioctl *param)
{
	int r = 0;
879
	unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
L
Linus Torvalds 已提交
880 881
	struct hash_cell *hc;
	struct mapped_device *md;
882
	struct dm_table *new_map, *old_map = NULL;
L
Linus Torvalds 已提交
883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903

	down_write(&_hash_lock);

	hc = __find_device_hash_cell(param);
	if (!hc) {
		DMWARN("device doesn't appear to be in the dev hash table.");
		up_write(&_hash_lock);
		return -ENXIO;
	}

	md = hc->md;

	new_map = hc->new_map;
	hc->new_map = NULL;
	param->flags &= ~DM_INACTIVE_PRESENT_FLAG;

	up_write(&_hash_lock);

	/* Do we need to load a new map ? */
	if (new_map) {
		/* Suspend if it isn't already suspended */
904
		if (param->flags & DM_SKIP_LOCKFS_FLAG)
905
			suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
906 907
		if (param->flags & DM_NOFLUSH_FLAG)
			suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
908
		if (!dm_suspended_md(md))
909
			dm_suspend(md, suspend_flags);
L
Linus Torvalds 已提交
910

911 912
		old_map = dm_swap_table(md, new_map);
		if (IS_ERR(old_map)) {
913
			dm_table_destroy(new_map);
L
Linus Torvalds 已提交
914
			dm_put(md);
915
			return PTR_ERR(old_map);
L
Linus Torvalds 已提交
916 917 918 919 920 921 922 923
		}

		if (dm_table_get_mode(new_map) & FMODE_WRITE)
			set_disk_ro(dm_disk(md), 0);
		else
			set_disk_ro(dm_disk(md), 1);
	}

924
	if (dm_suspended_md(md)) {
L
Linus Torvalds 已提交
925
		r = dm_resume(md);
926 927
		if (!r && !dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr))
			param->flags |= DM_UEVENT_GENERATED_FLAG;
928
	}
L
Linus Torvalds 已提交
929

930 931
	if (old_map)
		dm_table_destroy(old_map);
M
Milan Broz 已提交
932

933
	if (!r)
934
		__dev_status(md, param);
L
Linus Torvalds 已提交
935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963

	dm_put(md);
	return r;
}

/*
 * Set or unset the suspension state of a device.
 * If the device already is in the requested state we just return its status.
 */
static int dev_suspend(struct dm_ioctl *param, size_t param_size)
{
	if (param->flags & DM_SUSPEND_FLAG)
		return do_suspend(param);

	return do_resume(param);
}

/*
 * Copies device info back to user space, used by
 * the create and info ioctls.
 */
static int dev_status(struct dm_ioctl *param, size_t param_size)
{
	struct mapped_device *md;

	md = find_device(param);
	if (!md)
		return -ENXIO;

964
	__dev_status(md, param);
L
Linus Torvalds 已提交
965
	dm_put(md);
966 967

	return 0;
L
Linus Torvalds 已提交
968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041
}

/*
 * Build up the status struct for each target
 */
static void retrieve_status(struct dm_table *table,
			    struct dm_ioctl *param, size_t param_size)
{
	unsigned int i, num_targets;
	struct dm_target_spec *spec;
	char *outbuf, *outptr;
	status_type_t type;
	size_t remaining, len, used = 0;

	outptr = outbuf = get_result_buffer(param, param_size, &len);

	if (param->flags & DM_STATUS_TABLE_FLAG)
		type = STATUSTYPE_TABLE;
	else
		type = STATUSTYPE_INFO;

	/* Get all the target info */
	num_targets = dm_table_get_num_targets(table);
	for (i = 0; i < num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(table, i);

		remaining = len - (outptr - outbuf);
		if (remaining <= sizeof(struct dm_target_spec)) {
			param->flags |= DM_BUFFER_FULL_FLAG;
			break;
		}

		spec = (struct dm_target_spec *) outptr;

		spec->status = 0;
		spec->sector_start = ti->begin;
		spec->length = ti->len;
		strncpy(spec->target_type, ti->type->name,
			sizeof(spec->target_type));

		outptr += sizeof(struct dm_target_spec);
		remaining = len - (outptr - outbuf);
		if (remaining <= 0) {
			param->flags |= DM_BUFFER_FULL_FLAG;
			break;
		}

		/* Get the status/table string from the target driver */
		if (ti->type->status) {
			if (ti->type->status(ti, type, outptr, remaining)) {
				param->flags |= DM_BUFFER_FULL_FLAG;
				break;
			}
		} else
			outptr[0] = '\0';

		outptr += strlen(outptr) + 1;
		used = param->data_start + (outptr - outbuf);

		outptr = align_ptr(outptr);
		spec->next = outptr - outbuf;
	}

	if (used)
		param->data_size = used;

	param->target_count = num_targets;
}

/*
 * Wait for a device to report an event
 */
static int dev_wait(struct dm_ioctl *param, size_t param_size)
{
1042
	int r = 0;
L
Linus Torvalds 已提交
1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062
	struct mapped_device *md;
	struct dm_table *table;

	md = find_device(param);
	if (!md)
		return -ENXIO;

	/*
	 * Wait for a notification event
	 */
	if (dm_wait_event(md, param->event_nr)) {
		r = -ERESTARTSYS;
		goto out;
	}

	/*
	 * The userland program is going to want to know what
	 * changed to trigger the event, so we may as well tell
	 * him and save an ioctl.
	 */
1063
	__dev_status(md, param);
L
Linus Torvalds 已提交
1064

1065
	table = dm_get_live_or_inactive_table(md, param);
L
Linus Torvalds 已提交
1066 1067 1068 1069 1070
	if (table) {
		retrieve_status(table, param, param_size);
		dm_table_put(table);
	}

1071
out:
L
Linus Torvalds 已提交
1072
	dm_put(md);
1073

L
Linus Torvalds 已提交
1074 1075 1076
	return r;
}

1077
static inline fmode_t get_mode(struct dm_ioctl *param)
L
Linus Torvalds 已提交
1078
{
1079
	fmode_t mode = FMODE_READ | FMODE_WRITE;
L
Linus Torvalds 已提交
1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133

	if (param->flags & DM_READONLY_FLAG)
		mode = FMODE_READ;

	return mode;
}

static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
		       struct dm_target_spec **spec, char **target_params)
{
	*spec = (struct dm_target_spec *) ((unsigned char *) last + next);
	*target_params = (char *) (*spec + 1);

	if (*spec < (last + 1))
		return -EINVAL;

	return invalid_str(*target_params, end);
}

static int populate_table(struct dm_table *table,
			  struct dm_ioctl *param, size_t param_size)
{
	int r;
	unsigned int i = 0;
	struct dm_target_spec *spec = (struct dm_target_spec *) param;
	uint32_t next = param->data_start;
	void *end = (void *) param + param_size;
	char *target_params;

	if (!param->target_count) {
		DMWARN("populate_table: no targets specified");
		return -EINVAL;
	}

	for (i = 0; i < param->target_count; i++) {

		r = next_target(spec, next, end, &spec, &target_params);
		if (r) {
			DMWARN("unable to find target");
			return r;
		}

		r = dm_table_add_target(table, spec->target_type,
					(sector_t) spec->sector_start,
					(sector_t) spec->length,
					target_params);
		if (r) {
			DMWARN("error adding target to table");
			return r;
		}

		next = spec->next;
	}

K
Kiyoshi Ueda 已提交
1134 1135 1136 1137 1138 1139
	r = dm_table_set_type(table);
	if (r) {
		DMWARN("unable to set table type");
		return r;
	}

L
Linus Torvalds 已提交
1140 1141 1142
	return dm_table_complete(table);
}

M
Martin K. Petersen 已提交
1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155
static int table_prealloc_integrity(struct dm_table *t,
				    struct mapped_device *md)
{
	struct list_head *devices = dm_table_get_devices(t);
	struct dm_dev_internal *dd;

	list_for_each_entry(dd, devices, list)
		if (bdev_get_integrity(dd->dm_dev.bdev))
			return blk_integrity_register(dm_disk(md), NULL);

	return 0;
}

L
Linus Torvalds 已提交
1156 1157 1158 1159 1160
static int table_load(struct dm_ioctl *param, size_t param_size)
{
	int r;
	struct hash_cell *hc;
	struct dm_table *t;
M
Mike Anderson 已提交
1161 1162 1163 1164 1165
	struct mapped_device *md;

	md = find_device(param);
	if (!md)
		return -ENXIO;
L
Linus Torvalds 已提交
1166

M
Mike Anderson 已提交
1167
	r = dm_table_create(&t, get_mode(param), param->target_count, md);
L
Linus Torvalds 已提交
1168
	if (r)
M
Mike Anderson 已提交
1169
		goto out;
L
Linus Torvalds 已提交
1170 1171 1172

	r = populate_table(t, param, param_size);
	if (r) {
1173
		dm_table_destroy(t);
M
Mike Anderson 已提交
1174
		goto out;
L
Linus Torvalds 已提交
1175 1176
	}

M
Martin K. Petersen 已提交
1177 1178 1179 1180 1181 1182 1183 1184
	r = table_prealloc_integrity(t, md);
	if (r) {
		DMERR("%s: could not register integrity profile.",
		      dm_device_name(md));
		dm_table_destroy(t);
		goto out;
	}

K
Kiyoshi Ueda 已提交
1185 1186 1187 1188 1189 1190 1191
	r = dm_table_alloc_md_mempools(t);
	if (r) {
		DMWARN("unable to allocate mempools for this table");
		dm_table_destroy(t);
		goto out;
	}

1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206
	/* Protect md->type against concurrent table loads. */
	dm_lock_md_type(md);
	if (dm_get_md_type(md) == DM_TYPE_NONE)
		/* Initial table load: acquire type of table. */
		dm_set_md_type(md, dm_table_get_type(t));
	else if (dm_get_md_type(md) != dm_table_get_type(t)) {
		DMWARN("can't change device type after initial table load.");
		dm_table_destroy(t);
		dm_unlock_md_type(md);
		r = -EINVAL;
		goto out;
	}
	dm_unlock_md_type(md);

	/* stage inactive table */
L
Linus Torvalds 已提交
1207
	down_write(&_hash_lock);
M
Mike Anderson 已提交
1208 1209 1210
	hc = dm_get_mdptr(md);
	if (!hc || hc->md != md) {
		DMWARN("device has been removed from the dev hash table.");
1211
		dm_table_destroy(t);
M
Mike Anderson 已提交
1212 1213 1214
		up_write(&_hash_lock);
		r = -ENXIO;
		goto out;
L
Linus Torvalds 已提交
1215 1216 1217
	}

	if (hc->new_map)
1218
		dm_table_destroy(hc->new_map);
L
Linus Torvalds 已提交
1219
	hc->new_map = t;
M
Mike Anderson 已提交
1220 1221
	up_write(&_hash_lock);

L
Linus Torvalds 已提交
1222
	param->flags |= DM_INACTIVE_PRESENT_FLAG;
1223
	__dev_status(md, param);
M
Mike Anderson 已提交
1224 1225 1226

out:
	dm_put(md);
L
Linus Torvalds 已提交
1227 1228 1229 1230 1231 1232 1233

	return r;
}

static int table_clear(struct dm_ioctl *param, size_t param_size)
{
	struct hash_cell *hc;
1234
	struct mapped_device *md;
L
Linus Torvalds 已提交
1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245

	down_write(&_hash_lock);

	hc = __find_device_hash_cell(param);
	if (!hc) {
		DMWARN("device doesn't appear to be in the dev hash table.");
		up_write(&_hash_lock);
		return -ENXIO;
	}

	if (hc->new_map) {
1246
		dm_table_destroy(hc->new_map);
L
Linus Torvalds 已提交
1247 1248 1249 1250 1251
		hc->new_map = NULL;
	}

	param->flags &= ~DM_INACTIVE_PRESENT_FLAG;

1252
	__dev_status(hc->md, param);
1253
	md = hc->md;
L
Linus Torvalds 已提交
1254
	up_write(&_hash_lock);
1255
	dm_put(md);
1256 1257

	return 0;
L
Linus Torvalds 已提交
1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268
}

/*
 * Retrieves a list of devices used by a particular dm device.
 */
static void retrieve_deps(struct dm_table *table,
			  struct dm_ioctl *param, size_t param_size)
{
	unsigned int count = 0;
	struct list_head *tmp;
	size_t len, needed;
M
Mikulas Patocka 已提交
1269
	struct dm_dev_internal *dd;
L
Linus Torvalds 已提交
1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294
	struct dm_target_deps *deps;

	deps = get_result_buffer(param, param_size, &len);

	/*
	 * Count the devices.
	 */
	list_for_each (tmp, dm_table_get_devices(table))
		count++;

	/*
	 * Check we have enough space.
	 */
	needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
	if (len < needed) {
		param->flags |= DM_BUFFER_FULL_FLAG;
		return;
	}

	/*
	 * Fill in the devices.
	 */
	deps->count = count;
	count = 0;
	list_for_each_entry (dd, dm_table_get_devices(table), list)
M
Mikulas Patocka 已提交
1295
		deps->dev[count++] = huge_encode_dev(dd->dm_dev.bdev->bd_dev);
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Linus Torvalds 已提交
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	param->data_size = param->data_start + needed;
}

static int table_deps(struct dm_ioctl *param, size_t param_size)
{
	struct mapped_device *md;
	struct dm_table *table;

	md = find_device(param);
	if (!md)
		return -ENXIO;

1309
	__dev_status(md, param);
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1311
	table = dm_get_live_or_inactive_table(md, param);
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	if (table) {
		retrieve_deps(table, param, param_size);
		dm_table_put(table);
	}

	dm_put(md);
1318 1319

	return 0;
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}

/*
 * Return the status of a device as a text string for each
 * target.
 */
static int table_status(struct dm_ioctl *param, size_t param_size)
{
	struct mapped_device *md;
	struct dm_table *table;

	md = find_device(param);
	if (!md)
		return -ENXIO;

1335
	__dev_status(md, param);
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1337
	table = dm_get_live_or_inactive_table(md, param);
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	if (table) {
		retrieve_status(table, param, param_size);
		dm_table_put(table);
	}

	dm_put(md);
1344 1345

	return 0;
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}

/*
 * Pass a message to the target that's at the supplied device offset.
 */
static int target_message(struct dm_ioctl *param, size_t param_size)
{
	int r, argc;
	char **argv;
	struct mapped_device *md;
	struct dm_table *table;
	struct dm_target *ti;
	struct dm_target_msg *tmsg = (void *) param + param->data_start;

	md = find_device(param);
	if (!md)
		return -ENXIO;

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	if (tmsg < (struct dm_target_msg *) param->data ||
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	    invalid_str(tmsg->message, (void *) param + param_size)) {
		DMWARN("Invalid target message parameters.");
		r = -EINVAL;
		goto out;
	}

	r = dm_split_args(&argc, &argv, tmsg->message);
	if (r) {
		DMWARN("Failed to split target message parameters");
		goto out;
	}

1377
	table = dm_get_live_table(md);
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	if (!table)
		goto out_argv;

1381 1382 1383 1384 1385
	if (dm_deleting_md(md)) {
		r = -ENXIO;
		goto out_table;
	}

1386 1387
	ti = dm_table_find_target(table, tmsg->sector);
	if (!dm_target_is_valid(ti)) {
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		DMWARN("Target message sector outside device.");
		r = -EINVAL;
1390
	} else if (ti->type->message)
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		r = ti->type->message(ti, argc, argv);
	else {
		DMWARN("Target type does not support messages");
		r = -EINVAL;
	}

1397
 out_table:
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	dm_table_put(table);
 out_argv:
	kfree(argv);
 out:
	param->data_size = 0;
	dm_put(md);
	return r;
}

/*-----------------------------------------------------------------
 * Implementation of open/close/ioctl on the special char
 * device.
 *---------------------------------------------------------------*/
static ioctl_fn lookup_ioctl(unsigned int cmd)
{
	static struct {
		int cmd;
		ioctl_fn fn;
	} _ioctls[] = {
		{DM_VERSION_CMD, NULL},	/* version is dealt with elsewhere */
		{DM_REMOVE_ALL_CMD, remove_all},
		{DM_LIST_DEVICES_CMD, list_devices},

		{DM_DEV_CREATE_CMD, dev_create},
		{DM_DEV_REMOVE_CMD, dev_remove},
		{DM_DEV_RENAME_CMD, dev_rename},
		{DM_DEV_SUSPEND_CMD, dev_suspend},
		{DM_DEV_STATUS_CMD, dev_status},
		{DM_DEV_WAIT_CMD, dev_wait},

		{DM_TABLE_LOAD_CMD, table_load},
		{DM_TABLE_CLEAR_CMD, table_clear},
		{DM_TABLE_DEPS_CMD, table_deps},
		{DM_TABLE_STATUS_CMD, table_status},

		{DM_LIST_VERSIONS_CMD, list_versions},

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		{DM_TARGET_MSG_CMD, target_message},
		{DM_DEV_SET_GEOMETRY_CMD, dev_set_geometry}
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	};

	return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
}

/*
 * As well as checking the version compatibility this always
 * copies the kernel interface version out.
 */
static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
{
	uint32_t version[3];
	int r = 0;

	if (copy_from_user(version, user->version, sizeof(version)))
		return -EFAULT;

	if ((DM_VERSION_MAJOR != version[0]) ||
	    (DM_VERSION_MINOR < version[1])) {
		DMWARN("ioctl interface mismatch: "
		       "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
		       DM_VERSION_MAJOR, DM_VERSION_MINOR,
		       DM_VERSION_PATCHLEVEL,
		       version[0], version[1], version[2], cmd);
		r = -EINVAL;
	}

	/*
	 * Fill in the kernel version.
	 */
	version[0] = DM_VERSION_MAJOR;
	version[1] = DM_VERSION_MINOR;
	version[2] = DM_VERSION_PATCHLEVEL;
	if (copy_to_user(user->version, version, sizeof(version)))
		return -EFAULT;

	return r;
}

static void free_params(struct dm_ioctl *param)
{
	vfree(param);
}

static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
{
	struct dm_ioctl tmp, *dmi;

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	if (copy_from_user(&tmp, user, sizeof(tmp) - sizeof(tmp.data)))
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		return -EFAULT;

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	if (tmp.data_size < (sizeof(tmp) - sizeof(tmp.data)))
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		return -EINVAL;

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	dmi = vmalloc(tmp.data_size);
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	if (!dmi)
		return -ENOMEM;

	if (copy_from_user(dmi, user, tmp.data_size)) {
		vfree(dmi);
		return -EFAULT;
	}

	*param = dmi;
	return 0;
}

static int validate_params(uint cmd, struct dm_ioctl *param)
{
	/* Always clear this flag */
	param->flags &= ~DM_BUFFER_FULL_FLAG;
1508
	param->flags &= ~DM_UEVENT_GENERATED_FLAG;
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	/* Ignores parameters */
	if (cmd == DM_REMOVE_ALL_CMD ||
	    cmd == DM_LIST_DEVICES_CMD ||
	    cmd == DM_LIST_VERSIONS_CMD)
		return 0;

	if ((cmd == DM_DEV_CREATE_CMD)) {
		if (!*param->name) {
			DMWARN("name not supplied when creating device");
			return -EINVAL;
		}
	} else if ((*param->uuid && *param->name)) {
		DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
		return -EINVAL;
	}

	/* Ensure strings are terminated */
	param->name[DM_NAME_LEN - 1] = '\0';
	param->uuid[DM_UUID_LEN - 1] = '\0';

	return 0;
}

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Alasdair G Kergon 已提交
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static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
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{
	int r = 0;
	unsigned int cmd;
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Andrew Morton 已提交
1537
	struct dm_ioctl *uninitialized_var(param);
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	ioctl_fn fn = NULL;
	size_t param_size;

	/* only root can play with this */
	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	if (_IOC_TYPE(command) != DM_IOCTL)
		return -ENOTTY;

	cmd = _IOC_NR(command);

	/*
	 * Check the interface version passed in.  This also
	 * writes out the kernel's interface version.
	 */
	r = check_version(cmd, user);
	if (r)
		return r;

	/*
	 * Nothing more to do for the version command.
	 */
	if (cmd == DM_VERSION_CMD)
		return 0;

	fn = lookup_ioctl(cmd);
	if (!fn) {
		DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
		return -ENOTTY;
	}

	/*
	 * Trying to avoid low memory issues when a device is
	 * suspended.
	 */
	current->flags |= PF_MEMALLOC;

	/*
	 * Copy the parameters into kernel space.
	 */
	r = copy_params(user, &param);

1581 1582 1583 1584
	current->flags &= ~PF_MEMALLOC;

	if (r)
		return r;
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	r = validate_params(cmd, param);
	if (r)
		goto out;

	param_size = param->data_size;
	param->data_size = sizeof(*param);
	r = fn(param, param_size);

	/*
	 * Copy the results back to userland.
	 */
	if (!r && copy_to_user(user, param, param->data_size))
		r = -EFAULT;

 out:
	free_params(param);
	return r;
}

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Alasdair G Kergon 已提交
1605 1606 1607 1608 1609
static long dm_ctl_ioctl(struct file *file, uint command, ulong u)
{
	return (long)ctl_ioctl(command, (struct dm_ioctl __user *)u);
}

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Milan Broz 已提交
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#ifdef CONFIG_COMPAT
static long dm_compat_ctl_ioctl(struct file *file, uint command, ulong u)
{
	return (long)dm_ctl_ioctl(file, command, (ulong) compat_ptr(u));
}
#else
#define dm_compat_ctl_ioctl NULL
#endif

1619
static const struct file_operations _ctl_fops = {
A
Arnd Bergmann 已提交
1620
	.open = nonseekable_open,
A
Alasdair G Kergon 已提交
1621
	.unlocked_ioctl	 = dm_ctl_ioctl,
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Milan Broz 已提交
1622
	.compat_ioctl = dm_compat_ctl_ioctl,
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	.owner	 = THIS_MODULE,
};

static struct miscdevice _dm_misc = {
	.minor 		= MISC_DYNAMIC_MINOR,
	.name  		= DM_NAME,
1629
	.nodename	= "mapper/control",
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	.fops  		= &_ctl_fops
};

/*
 * Create misc character device and link to DM_DIR/control.
 */
int __init dm_interface_init(void)
{
	int r;

	r = dm_hash_init();
	if (r)
		return r;

	r = misc_register(&_dm_misc);
	if (r) {
		DMERR("misc_register failed for control device");
		dm_hash_exit();
		return r;
	}

	DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
	       DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
	       DM_DRIVER_EMAIL);
	return 0;
}

void dm_interface_exit(void)
{
	if (misc_deregister(&_dm_misc) < 0)
		DMERR("misc_deregister failed for control device");

	dm_hash_exit();
}
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/**
 * dm_copy_name_and_uuid - Copy mapped device name & uuid into supplied buffers
 * @md: Pointer to mapped_device
 * @name: Buffer (size DM_NAME_LEN) for name
 * @uuid: Buffer (size DM_UUID_LEN) for uuid or empty string if uuid not defined
 */
int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
{
	int r = 0;
	struct hash_cell *hc;

	if (!md)
		return -ENXIO;

M
Mikulas Patocka 已提交
1679
	mutex_lock(&dm_hash_cells_mutex);
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1680 1681 1682 1683 1684 1685
	hc = dm_get_mdptr(md);
	if (!hc || hc->md != md) {
		r = -ENXIO;
		goto out;
	}

1686 1687 1688 1689
	if (name)
		strcpy(name, hc->name);
	if (uuid)
		strcpy(uuid, hc->uuid ? : "");
M
Mike Anderson 已提交
1690 1691

out:
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Mikulas Patocka 已提交
1692
	mutex_unlock(&dm_hash_cells_mutex);
M
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1693 1694 1695

	return r;
}