dm-ioctl.c 34.3 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);

			/*
			 * 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)
		goto out;
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	param->flags &= ~DM_INACTIVE_PRESENT_FLAG;

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	__dev_status(md, param);

out:
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	dm_put(md);

	return r;
}

/*
 * 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)
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		return __get_name_cell(param->name);
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	md = dm_get_md(huge_decode_dev(param->dev));
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	if (!md)
		goto out;

	mdptr = dm_get_mdptr(md);
	if (!mdptr)
		dm_put(md);
A
Alasdair G Kergon 已提交
681

682
out:
A
Alasdair G Kergon 已提交
683
	return mdptr;
L
Linus Torvalds 已提交
684 685
}

686
static struct mapped_device *find_device(struct dm_ioctl *param)
L
Linus Torvalds 已提交
687 688 689 690 691 692 693 694 695 696 697 698 699
{
	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
700
		strlcpy(param->name, hc->name, sizeof(param->name));
L
Linus Torvalds 已提交
701
		if (hc->uuid)
R
Roel Kluin 已提交
702
			strlcpy(param->uuid, hc->uuid, sizeof(param->uuid));
L
Linus Torvalds 已提交
703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718
		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;
719
	struct mapped_device *md;
720
	int r;
L
Linus Torvalds 已提交
721 722 723 724 725 726 727 728 729 730

	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;
	}

731 732
	md = hc->md;

733 734 735 736 737 738 739 740 741 742 743
	/*
	 * 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
744 745
	__hash_remove(hc);
	up_write(&_hash_lock);
M
Milan Broz 已提交
746

747 748
	if (!dm_kobject_uevent(md, KOBJ_REMOVE, param->event_nr))
		param->flags |= DM_UEVENT_GENERATED_FLAG;
M
Milan Broz 已提交
749

750
	dm_put(md);
L
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751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770
	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;
771
	struct mapped_device *md;
L
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772

A
Alasdair G Kergon 已提交
773
	if (new_name < param->data ||
774 775
	    invalid_str(new_name, (void *) param + param_size) ||
	    strlen(new_name) > DM_NAME_LEN - 1) {
L
Linus Torvalds 已提交
776 777 778 779 780 781 782 783
		DMWARN("Invalid new logical volume name supplied.");
		return -EINVAL;
	}

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

784 785 786
	md = dm_hash_rename(param, new_name);
	if (IS_ERR(md))
		return PTR_ERR(md);
787

788 789 790 791
	__dev_status(md, param);
	dm_put(md);

	return 0;
L
Linus Torvalds 已提交
792 793
}

D
Darrick J. Wong 已提交
794 795 796 797 798 799 800 801 802 803 804 805
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;

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Alasdair G Kergon 已提交
806
	if (geostr < param->data ||
D
Darrick J. Wong 已提交
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	    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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static int do_suspend(struct dm_ioctl *param)
{
	int r = 0;
843
	unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
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Linus Torvalds 已提交
844 845 846 847 848 849
	struct mapped_device *md;

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

850
	if (param->flags & DM_SKIP_LOCKFS_FLAG)
851
		suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
852 853
	if (param->flags & DM_NOFLUSH_FLAG)
		suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
854

855
	if (!dm_suspended_md(md)) {
856
		r = dm_suspend(md, suspend_flags);
857 858 859
		if (r)
			goto out;
	}
L
Linus Torvalds 已提交
860

861
	__dev_status(md, param);
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862

863
out:
L
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864
	dm_put(md);
865

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866 867 868 869 870 871
	return r;
}

static int do_resume(struct dm_ioctl *param)
{
	int r = 0;
872
	unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
L
Linus Torvalds 已提交
873 874
	struct hash_cell *hc;
	struct mapped_device *md;
875
	struct dm_table *new_map, *old_map = NULL;
L
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876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896

	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 */
897
		if (param->flags & DM_SKIP_LOCKFS_FLAG)
898
			suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
899 900
		if (param->flags & DM_NOFLUSH_FLAG)
			suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
901
		if (!dm_suspended_md(md))
902
			dm_suspend(md, suspend_flags);
L
Linus Torvalds 已提交
903

904 905
		old_map = dm_swap_table(md, new_map);
		if (IS_ERR(old_map)) {
906
			dm_table_destroy(new_map);
L
Linus Torvalds 已提交
907
			dm_put(md);
908
			return PTR_ERR(old_map);
L
Linus Torvalds 已提交
909 910 911 912 913 914 915 916
		}

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

917
	if (dm_suspended_md(md)) {
L
Linus Torvalds 已提交
918
		r = dm_resume(md);
919 920
		if (!r && !dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr))
			param->flags |= DM_UEVENT_GENERATED_FLAG;
921
	}
L
Linus Torvalds 已提交
922

923 924
	if (old_map)
		dm_table_destroy(old_map);
M
Milan Broz 已提交
925

926
	if (!r)
927
		__dev_status(md, param);
L
Linus Torvalds 已提交
928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956

	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;

957
	__dev_status(md, param);
L
Linus Torvalds 已提交
958
	dm_put(md);
959 960

	return 0;
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961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 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
}

/*
 * 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)
{
1035
	int r = 0;
L
Linus Torvalds 已提交
1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055
	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.
	 */
1056
	__dev_status(md, param);
L
Linus Torvalds 已提交
1057

1058
	table = dm_get_live_or_inactive_table(md, param);
L
Linus Torvalds 已提交
1059 1060 1061 1062 1063
	if (table) {
		retrieve_status(table, param, param_size);
		dm_table_put(table);
	}

1064
out:
L
Linus Torvalds 已提交
1065
	dm_put(md);
1066

L
Linus Torvalds 已提交
1067 1068 1069
	return r;
}

1070
static inline fmode_t get_mode(struct dm_ioctl *param)
L
Linus Torvalds 已提交
1071
{
1072
	fmode_t mode = FMODE_READ | FMODE_WRITE;
L
Linus Torvalds 已提交
1073 1074 1075 1076 1077 1078 1079 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

	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
1127 1128 1129 1130 1131 1132
	r = dm_table_set_type(table);
	if (r) {
		DMWARN("unable to set table type");
		return r;
	}

L
Linus Torvalds 已提交
1133 1134 1135
	return dm_table_complete(table);
}

M
Martin K. Petersen 已提交
1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148
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
1149 1150 1151 1152 1153
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
1154 1155 1156 1157 1158
	struct mapped_device *md;

	md = find_device(param);
	if (!md)
		return -ENXIO;
L
Linus Torvalds 已提交
1159

M
Mike Anderson 已提交
1160
	r = dm_table_create(&t, get_mode(param), param->target_count, md);
L
Linus Torvalds 已提交
1161
	if (r)
M
Mike Anderson 已提交
1162
		goto out;
L
Linus Torvalds 已提交
1163 1164 1165

	r = populate_table(t, param, param_size);
	if (r) {
1166
		dm_table_destroy(t);
M
Mike Anderson 已提交
1167
		goto out;
L
Linus Torvalds 已提交
1168 1169
	}

M
Martin K. Petersen 已提交
1170 1171 1172 1173 1174 1175 1176 1177
	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
1178 1179 1180 1181 1182 1183 1184
	r = dm_table_alloc_md_mempools(t);
	if (r) {
		DMWARN("unable to allocate mempools for this table");
		dm_table_destroy(t);
		goto out;
	}

L
Linus Torvalds 已提交
1185
	down_write(&_hash_lock);
M
Mike Anderson 已提交
1186 1187 1188
	hc = dm_get_mdptr(md);
	if (!hc || hc->md != md) {
		DMWARN("device has been removed from the dev hash table.");
1189
		dm_table_destroy(t);
M
Mike Anderson 已提交
1190 1191 1192
		up_write(&_hash_lock);
		r = -ENXIO;
		goto out;
L
Linus Torvalds 已提交
1193 1194 1195
	}

	if (hc->new_map)
1196
		dm_table_destroy(hc->new_map);
L
Linus Torvalds 已提交
1197
	hc->new_map = t;
M
Mike Anderson 已提交
1198 1199
	up_write(&_hash_lock);

L
Linus Torvalds 已提交
1200
	param->flags |= DM_INACTIVE_PRESENT_FLAG;
1201
	__dev_status(md, param);
M
Mike Anderson 已提交
1202 1203 1204

out:
	dm_put(md);
L
Linus Torvalds 已提交
1205 1206 1207 1208 1209 1210 1211

	return r;
}

static int table_clear(struct dm_ioctl *param, size_t param_size)
{
	struct hash_cell *hc;
1212
	struct mapped_device *md;
L
Linus Torvalds 已提交
1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223

	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) {
1224
		dm_table_destroy(hc->new_map);
L
Linus Torvalds 已提交
1225 1226 1227 1228 1229
		hc->new_map = NULL;
	}

	param->flags &= ~DM_INACTIVE_PRESENT_FLAG;

1230
	__dev_status(hc->md, param);
1231
	md = hc->md;
L
Linus Torvalds 已提交
1232
	up_write(&_hash_lock);
1233
	dm_put(md);
1234 1235

	return 0;
L
Linus Torvalds 已提交
1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246
}

/*
 * 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
1247
	struct dm_dev_internal *dd;
L
Linus Torvalds 已提交
1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272
	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
1273
		deps->dev[count++] = huge_encode_dev(dd->dm_dev.bdev->bd_dev);
L
Linus Torvalds 已提交
1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286

	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;

1287
	__dev_status(md, param);
L
Linus Torvalds 已提交
1288

1289
	table = dm_get_live_or_inactive_table(md, param);
L
Linus Torvalds 已提交
1290 1291 1292 1293 1294 1295
	if (table) {
		retrieve_deps(table, param, param_size);
		dm_table_put(table);
	}

	dm_put(md);
1296 1297

	return 0;
L
Linus Torvalds 已提交
1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312
}

/*
 * 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;

1313
	__dev_status(md, param);
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1315
	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);
1322 1323

	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;
	}

1355
	table = dm_get_live_table(md);
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	if (!table)
		goto out_argv;

1359 1360 1361 1362 1363
	if (dm_deleting_md(md)) {
		r = -ENXIO;
		goto out_table;
	}

1364 1365
	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;
1368
	} 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;
	}

1375
 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;
1486
	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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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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	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);

1559 1560 1561 1562
	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
1583 1584 1585 1586 1587
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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#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

1597
static const struct file_operations _ctl_fops = {
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Alasdair G Kergon 已提交
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	.unlocked_ioctl	 = dm_ctl_ioctl,
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	.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,
1606
	.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;

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Mikulas Patocka 已提交
1656
	mutex_lock(&dm_hash_cells_mutex);
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1657 1658 1659 1660 1661 1662
	hc = dm_get_mdptr(md);
	if (!hc || hc->md != md) {
		r = -ENXIO;
		goto out;
	}

1663 1664 1665 1666
	if (name)
		strcpy(name, hc->name);
	if (uuid)
		strcpy(uuid, hc->uuid ? : "");
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out:
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Mikulas Patocka 已提交
1669
	mutex_unlock(&dm_hash_cells_mutex);
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	return r;
}