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dm-ioctl.c
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dm-ioctl.c
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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 <linux/hdreg.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);
}
if (hc->new_map)
dm_table_put(hc->new_map);
dm_put(hc->md);
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;
struct dm_table *table;
/*
* 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);
/*
* Wake up any dm event waiters.
*/
table = dm_get_table(hc->md);
if (table) {
dm_table_event(table);
dm_table_put(table);
}
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 += sizeof(struct dm_target_versions);
*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;
}
/*
* 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 struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
{
struct mapped_device *md;
void *mdptr = NULL;
if (*param->uuid)
return __get_uuid_cell(param->uuid);
if (*param->name)
return __get_name_cell(param->name);
md = dm_get_md(huge_decode_dev(param->dev));
if (md) {
mdptr = dm_get_mdptr(md);
dm_put(md);
}
return mdptr;
}
static 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 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;
if (geostr < (char *) (param + 1) ||
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);
if (!r)
r = __dev_status(md, param);
param->data_size = 0;
out:
dm_put(md);
return r;
}
static int do_suspend(struct dm_ioctl *param)
{
int r = 0;
int do_lockfs = 1;
struct mapped_device *md;
md = find_device(param);
if (!md)
return -ENXIO;
if (param->flags & DM_SKIP_LOCKFS_FLAG)
do_lockfs = 0;
if (!dm_suspended(md))
r = dm_suspend(md, do_lockfs);
if (!r)
r = __dev_status(md, param);
dm_put(md);
return r;
}
static int do_resume(struct dm_ioctl *param)
{
int r = 0;
int do_lockfs = 1;
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 (param->flags & DM_SKIP_LOCKFS_FLAG)
do_lockfs = 0;
if (!dm_suspended(md))
dm_suspend(md, do_lockfs);
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;