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linux/drivers/md/dm-ioctl.c
goggin, edward 269fd2a6f8 [PATCH] device-mapper: Trigger an event when a table is deleted 
If anything is waiting on a device's table when the device is removed, we
must first wake it up so it will release its reference.  Otherwise the
table's reference count will not drop to zero and the table will not get
removed.

Signed-Off-By: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-28 07:46:42 -07:00

1418 lines
29 KiB
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/*
* Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
* Copyright (C) 2004 - 2005 Red Hat, Inc. All rights reserved.
*
* 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/devfs_fs_kernel.h>
#include <linux/dm-ioctl.h>
#include <asm/uaccess.h>
#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];
static void dm_hash_remove_all(void);
/*
* Guards access to both hash tables.
*/
static DECLARE_RWSEM(_hash_lock);
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);
devfs_mk_dir(DM_DIR);
return 0;
}
static void dm_hash_exit(void)
{
dm_hash_remove_all();
devfs_remove(DM_DIR);
}
/*-----------------------------------------------------------------
* 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)
if (!strcmp(hc->name, str))
return hc;
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)
if (!strcmp(hc->uuid, str))
return hc;
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;
hc->name = kstrdup(name, GFP_KERNEL);
if (!hc->name) {
kfree(hc);
return NULL;
}
if (!uuid)
hc->uuid = NULL;
else {
hc->uuid = kstrdup(uuid, GFP_KERNEL);
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);
}
}
/*
* devfs stuff.
*/
static int register_with_devfs(struct hash_cell *hc)
{
struct gendisk *disk = dm_disk(hc->md);
devfs_mk_bdev(MKDEV(disk->major, disk->first_minor),
S_IFBLK | S_IRUSR | S_IWUSR | S_IRGRP,
DM_DIR "/%s", hc->name);
return 0;
}
static int unregister_with_devfs(struct hash_cell *hc)
{
devfs_remove(DM_DIR"/%s", hc->name);
return 0;
}
/*
* 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)
{
struct hash_cell *cell;
/*
* 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);
if (__get_name_cell(name))
goto bad;
list_add(&cell->name_list, _name_buckets + hash_str(name));
if (uuid) {
if (__get_uuid_cell(uuid)) {
list_del(&cell->name_list);
goto bad;
}
list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
}
register_with_devfs(cell);
dm_get(md);
dm_set_mdptr(md, cell);
up_write(&_hash_lock);
return 0;
bad:
up_write(&_hash_lock);
free_cell(cell);
return -EBUSY;
}
static void __hash_remove(struct hash_cell *hc)
{
struct dm_table *table;
/* remove from the dev hash */
list_del(&hc->uuid_list);
list_del(&hc->name_list);
unregister_with_devfs(hc);
dm_set_mdptr(hc->md, NULL);
table = dm_get_table(hc->md);
if (table) {
dm_table_event(table);
dm_table_put(table);
}
dm_put(hc->md);
if (hc->new_map)
dm_table_put(hc->new_map);
free_cell(hc);
}
static void dm_hash_remove_all(void)
{
int i;
struct hash_cell *hc;
struct list_head *tmp, *n;
down_write(&_hash_lock);
for (i = 0; i < NUM_BUCKETS; i++) {
list_for_each_safe (tmp, n, _name_buckets + i) {
hc = list_entry(tmp, struct hash_cell, name_list);
__hash_remove(hc);
}
}
up_write(&_hash_lock);
}
static int dm_hash_rename(const char *old, const char *new)
{
char *new_name, *old_name;
struct hash_cell *hc;
/*
* duplicate new.
*/
new_name = kstrdup(new, GFP_KERNEL);
if (!new_name)
return -ENOMEM;
down_write(&_hash_lock);
/*
* Is new free ?
*/
hc = __get_name_cell(new);
if (hc) {
DMWARN("asked to rename to an already existing name %s -> %s",
old, new);
up_write(&_hash_lock);
kfree(new_name);
return -EBUSY;
}
/*
* Is there such a device as 'old' ?
*/
hc = __get_name_cell(old);
if (!hc) {
DMWARN("asked to rename a non existent device %s -> %s",
old, new);
up_write(&_hash_lock);
kfree(new_name);
return -ENXIO;
}
/*
* rename and move the name cell.
*/
unregister_with_devfs(hc);
list_del(&hc->name_list);
old_name = hc->name;
hc->name = new_name;
list_add(&hc->name_list, _name_buckets + hash_str(new_name));
/* rename the device node in devfs */
register_with_devfs(hc);
up_write(&_hash_lock);
kfree(old_name);
return 0;
}
/*-----------------------------------------------------------------
* 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)
{
dm_hash_remove_all();
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);
nl->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
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;
*needed += strlen(tt->name);
*needed += sizeof(tt->version);
*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;
}
/*
* Fills in a dm_ioctl structure, ready for sending back to
* userland.
*/
static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
{
struct gendisk *disk = dm_disk(md);
struct dm_table *table;
struct block_device *bdev;
param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
DM_ACTIVE_PRESENT_FLAG);
if (dm_suspended(md))
param->flags |= DM_SUSPEND_FLAG;
param->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
if (!(param->flags & DM_SKIP_BDGET_FLAG)) {
bdev = bdget_disk(disk, 0);
if (!bdev)
return -ENXIO;
/*
* 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 = bdev->bd_openers;
bdput(bdev);
} else
param->open_count = -1;
if (disk->policy)
param->flags |= DM_READONLY_FLAG;
param->event_nr = dm_get_event_nr(md);
table = dm_get_table(md);
if (table) {
param->flags |= DM_ACTIVE_PRESENT_FLAG;
param->target_count = dm_table_get_num_targets(table);
dm_table_put(table);
} else
param->target_count = 0;
return 0;
}
static int dev_create(struct dm_ioctl *param, size_t param_size)
{
int r;
struct mapped_device *md;
r = check_name(param->name);
if (r)
return r;
if (param->flags & DM_PERSISTENT_DEV_FLAG)
r = dm_create_with_minor(MINOR(huge_decode_dev(param->dev)), &md);
else
r = dm_create(&md);
if (r)
return r;
r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
if (r) {
dm_put(md);
return r;
}
param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
r = __dev_status(md, param);
dm_put(md);
return r;
}
/*
* Always use UUID for lookups if it's present, otherwise use name or dev.
*/
static inline struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
{
if (*param->uuid)
return __get_uuid_cell(param->uuid);
else if (*param->name)
return __get_name_cell(param->name);
else
return dm_get_mdptr(huge_decode_dev(param->dev));
}
static inline struct mapped_device *find_device(struct dm_ioctl *param)
{
struct hash_cell *hc;
struct mapped_device *md = NULL;
down_read(&_hash_lock);
hc = __find_device_hash_cell(param);
if (hc) {
md = hc->md;
dm_get(md);
/*
* Sneakily write in both the name and the uuid
* while we have the cell.
*/
strncpy(param->name, hc->name, sizeof(param->name));
if (hc->uuid)
strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
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;
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;
}
__hash_remove(hc);
up_write(&_hash_lock);
param->data_size = 0;
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;
if (new_name < (char *) (param + 1) ||
invalid_str(new_name, (void *) param + param_size)) {
DMWARN("Invalid new logical volume name supplied.");
return -EINVAL;
}
r = check_name(new_name);
if (r)
return r;
param->data_size = 0;
return dm_hash_rename(param->name, new_name);
}
static int do_suspend(struct dm_ioctl *param)
{
int r = 0;
struct mapped_device *md;
md = find_device(param);
if (!md)
return -ENXIO;
if (!dm_suspended(md))
r = dm_suspend(md);
if (!r)
r = __dev_status(md, param);
dm_put(md);
return r;
}
static int do_resume(struct dm_ioctl *param)
{
int r = 0;
struct hash_cell *hc;
struct mapped_device *md;
struct dm_table *new_map;
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;
dm_get(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 */
if (!dm_suspended(md))
dm_suspend(md);
r = dm_swap_table(md, new_map);
if (r) {
dm_put(md);
dm_table_put(new_map);
return r;
}
if (dm_table_get_mode(new_map) & FMODE_WRITE)
set_disk_ro(dm_disk(md), 0);
else
set_disk_ro(dm_disk(md), 1);
dm_table_put(new_map);
}
if (dm_suspended(md))
r = dm_resume(md);
if (!r)
r = __dev_status(md, param);
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)
{
int r;
struct mapped_device *md;
md = find_device(param);
if (!md)
return -ENXIO;
r = __dev_status(md, param);
dm_put(md);
return r;
}
/*
* 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)
{
int r;
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.
*/
r = __dev_status(md, param);
if (r)
goto out;
table = dm_get_table(md);
if (table) {
retrieve_status(table, param, param_size);
dm_table_put(table);
}
out:
dm_put(md);
return r;
}
static inline int get_mode(struct dm_ioctl *param)
{
int mode = FMODE_READ | FMODE_WRITE;
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;
}
return dm_table_complete(table);
}
static int table_load(struct dm_ioctl *param, size_t param_size)
{
int r;
struct hash_cell *hc;
struct dm_table *t;
r = dm_table_create(&t, get_mode(param), param->target_count);
if (r)
return r;
r = populate_table(t, param, param_size);
if (r) {
dm_table_put(t);
return r;
}
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)
dm_table_put(hc->new_map);
hc->new_map = t;
param->flags |= DM_INACTIVE_PRESENT_FLAG;
r = __dev_status(hc->md, param);
up_write(&_hash_lock);
return r;
}
static int table_clear(struct dm_ioctl *param, size_t param_size)
{
int r;
struct hash_cell *hc;
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) {
dm_table_put(hc->new_map);
hc->new_map = NULL;
}
param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
r = __dev_status(hc->md, param);
up_write(&_hash_lock);
return r;
}
/*
* 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;
struct dm_dev *dd;
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)
deps->dev[count++] = huge_encode_dev(dd->bdev->bd_dev);
param->data_size = param->data_start + needed;
}
static int table_deps(struct dm_ioctl *param, size_t param_size)
{
int r = 0;
struct mapped_device *md;
struct dm_table *table;
md = find_device(param);
if (!md)
return -ENXIO;
r = __dev_status(md, param);
if (r)
goto out;
table = dm_get_table(md);
if (table) {
retrieve_deps(table, param, param_size);
dm_table_put(table);
}
out:
dm_put(md);
return r;
}
/*
* 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)
{
int r;
struct mapped_device *md;
struct dm_table *table;
md = find_device(param);
if (!md)
return -ENXIO;
r = __dev_status(md, param);
if (r)
goto out;
table = dm_get_table(md);
if (table) {
retrieve_status(table, param, param_size);
dm_table_put(table);
}
out:
dm_put(md);
return r;
}
/*
* 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;
r = __dev_status(md, param);
if (r)
goto out;
if (tmsg < (struct dm_target_msg *) (param + 1) ||
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;
}
table = dm_get_table(md);
if (!table)
goto out_argv;
if (tmsg->sector >= dm_table_get_size(table)) {
DMWARN("Target message sector outside device.");
r = -EINVAL;
goto out_table;
}
ti = dm_table_find_target(table, tmsg->sector);
if (ti->type->message)
r = ti->type->message(ti, argc, argv);
else {
DMWARN("Target type does not support messages");
r = -EINVAL;
}
out_table:
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},
{DM_TARGET_MSG_CMD, target_message}
};
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;
if (copy_from_user(&tmp, user, sizeof(tmp)))
return -EFAULT;
if (tmp.data_size < sizeof(tmp))
return -EINVAL;
dmi = (struct dm_ioctl *) vmalloc(tmp.data_size);
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;
/* 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;
}
static int ctl_ioctl(struct inode *inode, struct file *file,
uint command, ulong u)
{
int r = 0;
unsigned int cmd;
struct dm_ioctl *param;
struct dm_ioctl __user *user = (struct dm_ioctl __user *) u;
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);
if (r) {
current->flags &= ~PF_MEMALLOC;
return r;
}
/*
* FIXME: eventually we will remove the PF_MEMALLOC flag
* here. However the tools still do nasty things like
* 'load' while a device is suspended.
*/
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);
current->flags &= ~PF_MEMALLOC;
return r;
}
static struct file_operations _ctl_fops = {
.ioctl = ctl_ioctl,
.owner = THIS_MODULE,
};
static struct miscdevice _dm_misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = DM_NAME,
.devfs_name = "mapper/control",
.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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