blob: 4510ad8f971c366f4979403f4b0e13075f9d944b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
Alasdair G Kergon2b06cff2006-06-26 00:27:32 -07003 * Copyright (C) 2004 - 2006 Red Hat, Inc. All rights reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 *
5 * This file is released under the GPL.
6 */
7
8#include "dm.h"
9
10#include <linux/module.h>
11#include <linux/vmalloc.h>
12#include <linux/miscdevice.h>
13#include <linux/init.h>
14#include <linux/wait.h>
15#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/dm-ioctl.h>
Darrick J. Wong3ac51e72006-03-27 01:17:54 -080017#include <linux/hdreg.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
19#include <asm/uaccess.h>
20
Alasdair G Kergon72d94862006-06-26 00:27:35 -070021#define DM_MSG_PREFIX "ioctl"
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#define DM_DRIVER_EMAIL "dm-devel@redhat.com"
23
24/*-----------------------------------------------------------------
25 * The ioctl interface needs to be able to look up devices by
26 * name or uuid.
27 *---------------------------------------------------------------*/
28struct hash_cell {
29 struct list_head name_list;
30 struct list_head uuid_list;
31
32 char *name;
33 char *uuid;
34 struct mapped_device *md;
35 struct dm_table *new_map;
36};
37
38struct vers_iter {
39 size_t param_size;
40 struct dm_target_versions *vers, *old_vers;
41 char *end;
42 uint32_t flags;
43};
44
45
46#define NUM_BUCKETS 64
47#define MASK_BUCKETS (NUM_BUCKETS - 1)
48static struct list_head _name_buckets[NUM_BUCKETS];
49static struct list_head _uuid_buckets[NUM_BUCKETS];
50
Alasdair G Kergon5c6bd752006-06-26 00:27:34 -070051static void dm_hash_remove_all(int keep_open_devices);
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53/*
54 * Guards access to both hash tables.
55 */
56static DECLARE_RWSEM(_hash_lock);
57
58static void init_buckets(struct list_head *buckets)
59{
60 unsigned int i;
61
62 for (i = 0; i < NUM_BUCKETS; i++)
63 INIT_LIST_HEAD(buckets + i);
64}
65
66static int dm_hash_init(void)
67{
68 init_buckets(_name_buckets);
69 init_buckets(_uuid_buckets);
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 return 0;
71}
72
73static void dm_hash_exit(void)
74{
Alasdair G Kergon5c6bd752006-06-26 00:27:34 -070075 dm_hash_remove_all(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070076}
77
78/*-----------------------------------------------------------------
79 * Hash function:
80 * We're not really concerned with the str hash function being
81 * fast since it's only used by the ioctl interface.
82 *---------------------------------------------------------------*/
83static unsigned int hash_str(const char *str)
84{
85 const unsigned int hash_mult = 2654435387U;
86 unsigned int h = 0;
87
88 while (*str)
89 h = (h + (unsigned int) *str++) * hash_mult;
90
91 return h & MASK_BUCKETS;
92}
93
94/*-----------------------------------------------------------------
95 * Code for looking up a device by name
96 *---------------------------------------------------------------*/
97static struct hash_cell *__get_name_cell(const char *str)
98{
99 struct hash_cell *hc;
100 unsigned int h = hash_str(str);
101
102 list_for_each_entry (hc, _name_buckets + h, name_list)
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700103 if (!strcmp(hc->name, str)) {
104 dm_get(hc->md);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 return hc;
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700106 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107
108 return NULL;
109}
110
111static struct hash_cell *__get_uuid_cell(const char *str)
112{
113 struct hash_cell *hc;
114 unsigned int h = hash_str(str);
115
116 list_for_each_entry (hc, _uuid_buckets + h, uuid_list)
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700117 if (!strcmp(hc->uuid, str)) {
118 dm_get(hc->md);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 return hc;
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700120 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121
122 return NULL;
123}
124
125/*-----------------------------------------------------------------
126 * Inserting, removing and renaming a device.
127 *---------------------------------------------------------------*/
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128static struct hash_cell *alloc_cell(const char *name, const char *uuid,
129 struct mapped_device *md)
130{
131 struct hash_cell *hc;
132
133 hc = kmalloc(sizeof(*hc), GFP_KERNEL);
134 if (!hc)
135 return NULL;
136
Paulo Marques543537b2005-06-23 00:09:02 -0700137 hc->name = kstrdup(name, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 if (!hc->name) {
139 kfree(hc);
140 return NULL;
141 }
142
143 if (!uuid)
144 hc->uuid = NULL;
145
146 else {
Paulo Marques543537b2005-06-23 00:09:02 -0700147 hc->uuid = kstrdup(uuid, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 if (!hc->uuid) {
149 kfree(hc->name);
150 kfree(hc);
151 return NULL;
152 }
153 }
154
155 INIT_LIST_HEAD(&hc->name_list);
156 INIT_LIST_HEAD(&hc->uuid_list);
157 hc->md = md;
158 hc->new_map = NULL;
159 return hc;
160}
161
162static void free_cell(struct hash_cell *hc)
163{
164 if (hc) {
165 kfree(hc->name);
166 kfree(hc->uuid);
167 kfree(hc);
168 }
169}
170
171/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 * The kdev_t and uuid of a device can never change once it is
173 * initially inserted.
174 */
175static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md)
176{
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700177 struct hash_cell *cell, *hc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
179 /*
180 * Allocate the new cells.
181 */
182 cell = alloc_cell(name, uuid, md);
183 if (!cell)
184 return -ENOMEM;
185
186 /*
187 * Insert the cell into both hash tables.
188 */
189 down_write(&_hash_lock);
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700190 hc = __get_name_cell(name);
191 if (hc) {
192 dm_put(hc->md);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 goto bad;
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700194 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195
196 list_add(&cell->name_list, _name_buckets + hash_str(name));
197
198 if (uuid) {
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700199 hc = __get_uuid_cell(uuid);
200 if (hc) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 list_del(&cell->name_list);
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700202 dm_put(hc->md);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 goto bad;
204 }
205 list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
206 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 dm_get(md);
208 dm_set_mdptr(md, cell);
209 up_write(&_hash_lock);
210
211 return 0;
212
213 bad:
214 up_write(&_hash_lock);
215 free_cell(cell);
216 return -EBUSY;
217}
218
219static void __hash_remove(struct hash_cell *hc)
220{
goggin, edward269fd2a2005-09-27 21:45:44 -0700221 struct dm_table *table;
222
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 /* remove from the dev hash */
224 list_del(&hc->uuid_list);
225 list_del(&hc->name_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 dm_set_mdptr(hc->md, NULL);
goggin, edward269fd2a2005-09-27 21:45:44 -0700227
228 table = dm_get_table(hc->md);
229 if (table) {
230 dm_table_event(table);
231 dm_table_put(table);
232 }
233
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 if (hc->new_map)
235 dm_table_put(hc->new_map);
Mike Anderson1134e5a2006-03-27 01:17:54 -0800236 dm_put(hc->md);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 free_cell(hc);
238}
239
Alasdair G Kergon5c6bd752006-06-26 00:27:34 -0700240static void dm_hash_remove_all(int keep_open_devices)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241{
Alasdair G Kergon5c6bd752006-06-26 00:27:34 -0700242 int i, dev_skipped, dev_removed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 struct hash_cell *hc;
244 struct list_head *tmp, *n;
245
246 down_write(&_hash_lock);
Alasdair G Kergon5c6bd752006-06-26 00:27:34 -0700247
248retry:
249 dev_skipped = dev_removed = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 for (i = 0; i < NUM_BUCKETS; i++) {
251 list_for_each_safe (tmp, n, _name_buckets + i) {
252 hc = list_entry(tmp, struct hash_cell, name_list);
Alasdair G Kergon5c6bd752006-06-26 00:27:34 -0700253
254 if (keep_open_devices &&
255 dm_lock_for_deletion(hc->md)) {
256 dev_skipped++;
257 continue;
258 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 __hash_remove(hc);
Alasdair G Kergon5c6bd752006-06-26 00:27:34 -0700260 dev_removed = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 }
262 }
Alasdair G Kergon5c6bd752006-06-26 00:27:34 -0700263
264 /*
265 * Some mapped devices may be using other mapped devices, so if any
266 * still exist, repeat until we make no further progress.
267 */
268 if (dev_skipped) {
269 if (dev_removed)
270 goto retry;
271
272 DMWARN("remove_all left %d open device(s)", dev_skipped);
273 }
274
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 up_write(&_hash_lock);
276}
277
278static int dm_hash_rename(const char *old, const char *new)
279{
280 char *new_name, *old_name;
281 struct hash_cell *hc;
goggin, edward81f17772006-01-06 00:20:01 -0800282 struct dm_table *table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283
284 /*
285 * duplicate new.
286 */
Paulo Marques543537b2005-06-23 00:09:02 -0700287 new_name = kstrdup(new, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 if (!new_name)
289 return -ENOMEM;
290
291 down_write(&_hash_lock);
292
293 /*
294 * Is new free ?
295 */
296 hc = __get_name_cell(new);
297 if (hc) {
298 DMWARN("asked to rename to an already existing name %s -> %s",
299 old, new);
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700300 dm_put(hc->md);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 up_write(&_hash_lock);
302 kfree(new_name);
303 return -EBUSY;
304 }
305
306 /*
307 * Is there such a device as 'old' ?
308 */
309 hc = __get_name_cell(old);
310 if (!hc) {
311 DMWARN("asked to rename a non existent device %s -> %s",
312 old, new);
313 up_write(&_hash_lock);
314 kfree(new_name);
315 return -ENXIO;
316 }
317
318 /*
319 * rename and move the name cell.
320 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 list_del(&hc->name_list);
322 old_name = hc->name;
323 hc->name = new_name;
324 list_add(&hc->name_list, _name_buckets + hash_str(new_name));
325
goggin, edward81f17772006-01-06 00:20:01 -0800326 /*
327 * Wake up any dm event waiters.
328 */
329 table = dm_get_table(hc->md);
330 if (table) {
331 dm_table_event(table);
332 dm_table_put(table);
333 }
334
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700335 dm_put(hc->md);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 up_write(&_hash_lock);
337 kfree(old_name);
338 return 0;
339}
340
341/*-----------------------------------------------------------------
342 * Implementation of the ioctl commands
343 *---------------------------------------------------------------*/
344/*
345 * All the ioctl commands get dispatched to functions with this
346 * prototype.
347 */
348typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
349
350static int remove_all(struct dm_ioctl *param, size_t param_size)
351{
Alasdair G Kergon5c6bd752006-06-26 00:27:34 -0700352 dm_hash_remove_all(1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 param->data_size = 0;
354 return 0;
355}
356
357/*
358 * Round up the ptr to an 8-byte boundary.
359 */
360#define ALIGN_MASK 7
361static inline void *align_ptr(void *ptr)
362{
363 return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
364}
365
366/*
367 * Retrieves the data payload buffer from an already allocated
368 * struct dm_ioctl.
369 */
370static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
371 size_t *len)
372{
373 param->data_start = align_ptr(param + 1) - (void *) param;
374
375 if (param->data_start < param_size)
376 *len = param_size - param->data_start;
377 else
378 *len = 0;
379
380 return ((void *) param) + param->data_start;
381}
382
383static int list_devices(struct dm_ioctl *param, size_t param_size)
384{
385 unsigned int i;
386 struct hash_cell *hc;
387 size_t len, needed = 0;
388 struct gendisk *disk;
389 struct dm_name_list *nl, *old_nl = NULL;
390
391 down_write(&_hash_lock);
392
393 /*
394 * Loop through all the devices working out how much
395 * space we need.
396 */
397 for (i = 0; i < NUM_BUCKETS; i++) {
398 list_for_each_entry (hc, _name_buckets + i, name_list) {
399 needed += sizeof(struct dm_name_list);
400 needed += strlen(hc->name) + 1;
401 needed += ALIGN_MASK;
402 }
403 }
404
405 /*
406 * Grab our output buffer.
407 */
408 nl = get_result_buffer(param, param_size, &len);
409 if (len < needed) {
410 param->flags |= DM_BUFFER_FULL_FLAG;
411 goto out;
412 }
413 param->data_size = param->data_start + needed;
414
415 nl->dev = 0; /* Flags no data */
416
417 /*
418 * Now loop through filling out the names.
419 */
420 for (i = 0; i < NUM_BUCKETS; i++) {
421 list_for_each_entry (hc, _name_buckets + i, name_list) {
422 if (old_nl)
423 old_nl->next = (uint32_t) ((void *) nl -
424 (void *) old_nl);
425 disk = dm_disk(hc->md);
426 nl->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
427 nl->next = 0;
428 strcpy(nl->name, hc->name);
429
430 old_nl = nl;
431 nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
432 }
433 }
434
435 out:
436 up_write(&_hash_lock);
437 return 0;
438}
439
440static void list_version_get_needed(struct target_type *tt, void *needed_param)
441{
442 size_t *needed = needed_param;
443
Alasdair G Kergonc4cc6632005-11-21 21:32:33 -0800444 *needed += sizeof(struct dm_target_versions);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445 *needed += strlen(tt->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 *needed += ALIGN_MASK;
447}
448
449static void list_version_get_info(struct target_type *tt, void *param)
450{
451 struct vers_iter *info = param;
452
453 /* Check space - it might have changed since the first iteration */
454 if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
455 info->end) {
456
457 info->flags = DM_BUFFER_FULL_FLAG;
458 return;
459 }
460
461 if (info->old_vers)
462 info->old_vers->next = (uint32_t) ((void *)info->vers -
463 (void *)info->old_vers);
464 info->vers->version[0] = tt->version[0];
465 info->vers->version[1] = tt->version[1];
466 info->vers->version[2] = tt->version[2];
467 info->vers->next = 0;
468 strcpy(info->vers->name, tt->name);
469
470 info->old_vers = info->vers;
471 info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
472}
473
474static int list_versions(struct dm_ioctl *param, size_t param_size)
475{
476 size_t len, needed = 0;
477 struct dm_target_versions *vers;
478 struct vers_iter iter_info;
479
480 /*
481 * Loop through all the devices working out how much
482 * space we need.
483 */
484 dm_target_iterate(list_version_get_needed, &needed);
485
486 /*
487 * Grab our output buffer.
488 */
489 vers = get_result_buffer(param, param_size, &len);
490 if (len < needed) {
491 param->flags |= DM_BUFFER_FULL_FLAG;
492 goto out;
493 }
494 param->data_size = param->data_start + needed;
495
496 iter_info.param_size = param_size;
497 iter_info.old_vers = NULL;
498 iter_info.vers = vers;
499 iter_info.flags = 0;
500 iter_info.end = (char *)vers+len;
501
502 /*
503 * Now loop through filling out the names & versions.
504 */
505 dm_target_iterate(list_version_get_info, &iter_info);
506 param->flags |= iter_info.flags;
507
508 out:
509 return 0;
510}
511
512
513
514static int check_name(const char *name)
515{
516 if (strchr(name, '/')) {
517 DMWARN("invalid device name");
518 return -EINVAL;
519 }
520
521 return 0;
522}
523
524/*
525 * Fills in a dm_ioctl structure, ready for sending back to
526 * userland.
527 */
528static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
529{
530 struct gendisk *disk = dm_disk(md);
531 struct dm_table *table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532
533 param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
534 DM_ACTIVE_PRESENT_FLAG);
535
536 if (dm_suspended(md))
537 param->flags |= DM_SUSPEND_FLAG;
538
539 param->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
540
Alasdair G Kergon5c6bd752006-06-26 00:27:34 -0700541 /*
542 * Yes, this will be out of date by the time it gets back
543 * to userland, but it is still very useful for
544 * debugging.
545 */
546 param->open_count = dm_open_count(md);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547
548 if (disk->policy)
549 param->flags |= DM_READONLY_FLAG;
550
551 param->event_nr = dm_get_event_nr(md);
552
553 table = dm_get_table(md);
554 if (table) {
555 param->flags |= DM_ACTIVE_PRESENT_FLAG;
556 param->target_count = dm_table_get_num_targets(table);
557 dm_table_put(table);
558 } else
559 param->target_count = 0;
560
561 return 0;
562}
563
564static int dev_create(struct dm_ioctl *param, size_t param_size)
565{
Alasdair G Kergon2b06cff2006-06-26 00:27:32 -0700566 int r, m = DM_ANY_MINOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 struct mapped_device *md;
568
569 r = check_name(param->name);
570 if (r)
571 return r;
572
573 if (param->flags & DM_PERSISTENT_DEV_FLAG)
Alasdair G Kergon2b06cff2006-06-26 00:27:32 -0700574 m = MINOR(huge_decode_dev(param->dev));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575
Alasdair G Kergon2b06cff2006-06-26 00:27:32 -0700576 r = dm_create(m, &md);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 if (r)
578 return r;
579
580 r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
581 if (r) {
582 dm_put(md);
583 return r;
584 }
585
586 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
587
588 r = __dev_status(md, param);
589 dm_put(md);
590
591 return r;
592}
593
594/*
595 * Always use UUID for lookups if it's present, otherwise use name or dev.
596 */
Arjan van de Ven858119e2006-01-14 13:20:43 -0800597static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598{
Alasdair G Kergon9ade92a2006-03-27 01:17:53 -0800599 struct mapped_device *md;
600 void *mdptr = NULL;
601
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 if (*param->uuid)
603 return __get_uuid_cell(param->uuid);
Alasdair G Kergon9ade92a2006-03-27 01:17:53 -0800604
605 if (*param->name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 return __get_name_cell(param->name);
Alasdair G Kergon9ade92a2006-03-27 01:17:53 -0800607
608 md = dm_get_md(huge_decode_dev(param->dev));
Alasdair G Kergonbfc5ecd2006-11-08 17:44:42 -0800609 if (!md)
610 goto out;
Alasdair G Kergon9ade92a2006-03-27 01:17:53 -0800611
Alasdair G Kergonbfc5ecd2006-11-08 17:44:42 -0800612 mdptr = dm_get_mdptr(md);
613 if (!mdptr)
614 dm_put(md);
615
616out:
Alasdair G Kergon9ade92a2006-03-27 01:17:53 -0800617 return mdptr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618}
619
Arjan van de Ven858119e2006-01-14 13:20:43 -0800620static struct mapped_device *find_device(struct dm_ioctl *param)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621{
622 struct hash_cell *hc;
623 struct mapped_device *md = NULL;
624
625 down_read(&_hash_lock);
626 hc = __find_device_hash_cell(param);
627 if (hc) {
628 md = hc->md;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629
630 /*
631 * Sneakily write in both the name and the uuid
632 * while we have the cell.
633 */
634 strncpy(param->name, hc->name, sizeof(param->name));
635 if (hc->uuid)
636 strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
637 else
638 param->uuid[0] = '\0';
639
640 if (hc->new_map)
641 param->flags |= DM_INACTIVE_PRESENT_FLAG;
642 else
643 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
644 }
645 up_read(&_hash_lock);
646
647 return md;
648}
649
650static int dev_remove(struct dm_ioctl *param, size_t param_size)
651{
652 struct hash_cell *hc;
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700653 struct mapped_device *md;
Alasdair G Kergon5c6bd752006-06-26 00:27:34 -0700654 int r;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655
656 down_write(&_hash_lock);
657 hc = __find_device_hash_cell(param);
658
659 if (!hc) {
660 DMWARN("device doesn't appear to be in the dev hash table.");
661 up_write(&_hash_lock);
662 return -ENXIO;
663 }
664
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700665 md = hc->md;
666
Alasdair G Kergon5c6bd752006-06-26 00:27:34 -0700667 /*
668 * Ensure the device is not open and nothing further can open it.
669 */
670 r = dm_lock_for_deletion(md);
671 if (r) {
672 DMWARN("unable to remove open device %s", hc->name);
673 up_write(&_hash_lock);
674 dm_put(md);
675 return r;
676 }
677
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 __hash_remove(hc);
679 up_write(&_hash_lock);
Jeff Mahoney7ec75f22006-06-26 00:27:24 -0700680 dm_put(md);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 param->data_size = 0;
682 return 0;
683}
684
685/*
686 * Check a string doesn't overrun the chunk of
687 * memory we copied from userland.
688 */
689static int invalid_str(char *str, void *end)
690{
691 while ((void *) str < end)
692 if (!*str++)
693 return 0;
694
695 return -EINVAL;
696}
697
698static int dev_rename(struct dm_ioctl *param, size_t param_size)
699{
700 int r;
701 char *new_name = (char *) param + param->data_start;
702
703 if (new_name < (char *) (param + 1) ||
704 invalid_str(new_name, (void *) param + param_size)) {
705 DMWARN("Invalid new logical volume name supplied.");
706 return -EINVAL;
707 }
708
709 r = check_name(new_name);
710 if (r)
711 return r;
712
713 param->data_size = 0;
714 return dm_hash_rename(param->name, new_name);
715}
716
Darrick J. Wong3ac51e72006-03-27 01:17:54 -0800717static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
718{
719 int r = -EINVAL, x;
720 struct mapped_device *md;
721 struct hd_geometry geometry;
722 unsigned long indata[4];
723 char *geostr = (char *) param + param->data_start;
724
725 md = find_device(param);
726 if (!md)
727 return -ENXIO;
728
729 if (geostr < (char *) (param + 1) ||
730 invalid_str(geostr, (void *) param + param_size)) {
731 DMWARN("Invalid geometry supplied.");
732 goto out;
733 }
734
735 x = sscanf(geostr, "%lu %lu %lu %lu", indata,
736 indata + 1, indata + 2, indata + 3);
737
738 if (x != 4) {
739 DMWARN("Unable to interpret geometry settings.");
740 goto out;
741 }
742
743 if (indata[0] > 65535 || indata[1] > 255 ||
744 indata[2] > 255 || indata[3] > ULONG_MAX) {
745 DMWARN("Geometry exceeds range limits.");
746 goto out;
747 }
748
749 geometry.cylinders = indata[0];
750 geometry.heads = indata[1];
751 geometry.sectors = indata[2];
752 geometry.start = indata[3];
753
754 r = dm_set_geometry(md, &geometry);
755 if (!r)
756 r = __dev_status(md, param);
757
758 param->data_size = 0;
759
760out:
761 dm_put(md);
762 return r;
763}
764
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765static int do_suspend(struct dm_ioctl *param)
766{
767 int r = 0;
Alasdair G Kergon6da487d2006-01-06 00:20:07 -0800768 int do_lockfs = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 struct mapped_device *md;
770
771 md = find_device(param);
772 if (!md)
773 return -ENXIO;
774
Alasdair G Kergon6da487d2006-01-06 00:20:07 -0800775 if (param->flags & DM_SKIP_LOCKFS_FLAG)
776 do_lockfs = 0;
777
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778 if (!dm_suspended(md))
Alasdair G Kergon6da487d2006-01-06 00:20:07 -0800779 r = dm_suspend(md, do_lockfs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780
781 if (!r)
782 r = __dev_status(md, param);
783
784 dm_put(md);
785 return r;
786}
787
788static int do_resume(struct dm_ioctl *param)
789{
790 int r = 0;
Alasdair G Kergon6da487d2006-01-06 00:20:07 -0800791 int do_lockfs = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 struct hash_cell *hc;
793 struct mapped_device *md;
794 struct dm_table *new_map;
795
796 down_write(&_hash_lock);
797
798 hc = __find_device_hash_cell(param);
799 if (!hc) {
800 DMWARN("device doesn't appear to be in the dev hash table.");
801 up_write(&_hash_lock);
802 return -ENXIO;
803 }
804
805 md = hc->md;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806
807 new_map = hc->new_map;
808 hc->new_map = NULL;
809 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
810
811 up_write(&_hash_lock);
812
813 /* Do we need to load a new map ? */
814 if (new_map) {
815 /* Suspend if it isn't already suspended */
Alasdair G Kergon6da487d2006-01-06 00:20:07 -0800816 if (param->flags & DM_SKIP_LOCKFS_FLAG)
817 do_lockfs = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 if (!dm_suspended(md))
Alasdair G Kergon6da487d2006-01-06 00:20:07 -0800819 dm_suspend(md, do_lockfs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820
821 r = dm_swap_table(md, new_map);
822 if (r) {
823 dm_put(md);
824 dm_table_put(new_map);
825 return r;
826 }
827
828 if (dm_table_get_mode(new_map) & FMODE_WRITE)
829 set_disk_ro(dm_disk(md), 0);
830 else
831 set_disk_ro(dm_disk(md), 1);
832
833 dm_table_put(new_map);
834 }
835
836 if (dm_suspended(md))
837 r = dm_resume(md);
838
839 if (!r)
840 r = __dev_status(md, param);
841
842 dm_put(md);
843 return r;
844}
845
846/*
847 * Set or unset the suspension state of a device.
848 * If the device already is in the requested state we just return its status.
849 */
850static int dev_suspend(struct dm_ioctl *param, size_t param_size)
851{
852 if (param->flags & DM_SUSPEND_FLAG)
853 return do_suspend(param);
854
855 return do_resume(param);
856}
857
858/*
859 * Copies device info back to user space, used by
860 * the create and info ioctls.
861 */
862static int dev_status(struct dm_ioctl *param, size_t param_size)
863{
864 int r;
865 struct mapped_device *md;
866
867 md = find_device(param);
868 if (!md)
869 return -ENXIO;
870
871 r = __dev_status(md, param);
872 dm_put(md);
873 return r;
874}
875
876/*
877 * Build up the status struct for each target
878 */
879static void retrieve_status(struct dm_table *table,
880 struct dm_ioctl *param, size_t param_size)
881{
882 unsigned int i, num_targets;
883 struct dm_target_spec *spec;
884 char *outbuf, *outptr;
885 status_type_t type;
886 size_t remaining, len, used = 0;
887
888 outptr = outbuf = get_result_buffer(param, param_size, &len);
889
890 if (param->flags & DM_STATUS_TABLE_FLAG)
891 type = STATUSTYPE_TABLE;
892 else
893 type = STATUSTYPE_INFO;
894
895 /* Get all the target info */
896 num_targets = dm_table_get_num_targets(table);
897 for (i = 0; i < num_targets; i++) {
898 struct dm_target *ti = dm_table_get_target(table, i);
899
900 remaining = len - (outptr - outbuf);
901 if (remaining <= sizeof(struct dm_target_spec)) {
902 param->flags |= DM_BUFFER_FULL_FLAG;
903 break;
904 }
905
906 spec = (struct dm_target_spec *) outptr;
907
908 spec->status = 0;
909 spec->sector_start = ti->begin;
910 spec->length = ti->len;
911 strncpy(spec->target_type, ti->type->name,
912 sizeof(spec->target_type));
913
914 outptr += sizeof(struct dm_target_spec);
915 remaining = len - (outptr - outbuf);
916 if (remaining <= 0) {
917 param->flags |= DM_BUFFER_FULL_FLAG;
918 break;
919 }
920
921 /* Get the status/table string from the target driver */
922 if (ti->type->status) {
923 if (ti->type->status(ti, type, outptr, remaining)) {
924 param->flags |= DM_BUFFER_FULL_FLAG;
925 break;
926 }
927 } else
928 outptr[0] = '\0';
929
930 outptr += strlen(outptr) + 1;
931 used = param->data_start + (outptr - outbuf);
932
933 outptr = align_ptr(outptr);
934 spec->next = outptr - outbuf;
935 }
936
937 if (used)
938 param->data_size = used;
939
940 param->target_count = num_targets;
941}
942
943/*
944 * Wait for a device to report an event
945 */
946static int dev_wait(struct dm_ioctl *param, size_t param_size)
947{
948 int r;
949 struct mapped_device *md;
950 struct dm_table *table;
951
952 md = find_device(param);
953 if (!md)
954 return -ENXIO;
955
956 /*
957 * Wait for a notification event
958 */
959 if (dm_wait_event(md, param->event_nr)) {
960 r = -ERESTARTSYS;
961 goto out;
962 }
963
964 /*
965 * The userland program is going to want to know what
966 * changed to trigger the event, so we may as well tell
967 * him and save an ioctl.
968 */
969 r = __dev_status(md, param);
970 if (r)
971 goto out;
972
973 table = dm_get_table(md);
974 if (table) {
975 retrieve_status(table, param, param_size);
976 dm_table_put(table);
977 }
978
979 out:
980 dm_put(md);
981 return r;
982}
983
984static inline int get_mode(struct dm_ioctl *param)
985{
986 int mode = FMODE_READ | FMODE_WRITE;
987
988 if (param->flags & DM_READONLY_FLAG)
989 mode = FMODE_READ;
990
991 return mode;
992}
993
994static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
995 struct dm_target_spec **spec, char **target_params)
996{
997 *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
998 *target_params = (char *) (*spec + 1);
999
1000 if (*spec < (last + 1))
1001 return -EINVAL;
1002
1003 return invalid_str(*target_params, end);
1004}
1005
1006static int populate_table(struct dm_table *table,
1007 struct dm_ioctl *param, size_t param_size)
1008{
1009 int r;
1010 unsigned int i = 0;
1011 struct dm_target_spec *spec = (struct dm_target_spec *) param;
1012 uint32_t next = param->data_start;
1013 void *end = (void *) param + param_size;
1014 char *target_params;
1015
1016 if (!param->target_count) {
1017 DMWARN("populate_table: no targets specified");
1018 return -EINVAL;
1019 }
1020
1021 for (i = 0; i < param->target_count; i++) {
1022
1023 r = next_target(spec, next, end, &spec, &target_params);
1024 if (r) {
1025 DMWARN("unable to find target");
1026 return r;
1027 }
1028
1029 r = dm_table_add_target(table, spec->target_type,
1030 (sector_t) spec->sector_start,
1031 (sector_t) spec->length,
1032 target_params);
1033 if (r) {
1034 DMWARN("error adding target to table");
1035 return r;
1036 }
1037
1038 next = spec->next;
1039 }
1040
1041 return dm_table_complete(table);
1042}
1043
1044static int table_load(struct dm_ioctl *param, size_t param_size)
1045{
1046 int r;
1047 struct hash_cell *hc;
1048 struct dm_table *t;
Mike Anderson1134e5a2006-03-27 01:17:54 -08001049 struct mapped_device *md;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001050
Mike Anderson1134e5a2006-03-27 01:17:54 -08001051 md = find_device(param);
1052 if (!md)
1053 return -ENXIO;
1054
1055 r = dm_table_create(&t, get_mode(param), param->target_count, md);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001056 if (r)
Mike Anderson1134e5a2006-03-27 01:17:54 -08001057 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001058
1059 r = populate_table(t, param, param_size);
1060 if (r) {
1061 dm_table_put(t);
Mike Anderson1134e5a2006-03-27 01:17:54 -08001062 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001063 }
1064
1065 down_write(&_hash_lock);
Mike Anderson1134e5a2006-03-27 01:17:54 -08001066 hc = dm_get_mdptr(md);
1067 if (!hc || hc->md != md) {
1068 DMWARN("device has been removed from the dev hash table.");
Kiyoshi Uedab6fcc802005-11-21 21:32:32 -08001069 dm_table_put(t);
Mike Anderson1134e5a2006-03-27 01:17:54 -08001070 up_write(&_hash_lock);
1071 r = -ENXIO;
1072 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073 }
1074
1075 if (hc->new_map)
1076 dm_table_put(hc->new_map);
1077 hc->new_map = t;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001078 up_write(&_hash_lock);
Mike Anderson1134e5a2006-03-27 01:17:54 -08001079
1080 param->flags |= DM_INACTIVE_PRESENT_FLAG;
1081 r = __dev_status(md, param);
1082
1083out:
1084 dm_put(md);
1085
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086 return r;
1087}
1088
1089static int table_clear(struct dm_ioctl *param, size_t param_size)
1090{
1091 int r;
1092 struct hash_cell *hc;
Jeff Mahoney7ec75f22006-06-26 00:27:24 -07001093 struct mapped_device *md;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094
1095 down_write(&_hash_lock);
1096
1097 hc = __find_device_hash_cell(param);
1098 if (!hc) {
1099 DMWARN("device doesn't appear to be in the dev hash table.");
1100 up_write(&_hash_lock);
1101 return -ENXIO;
1102 }
1103
1104 if (hc->new_map) {
1105 dm_table_put(hc->new_map);
1106 hc->new_map = NULL;
1107 }
1108
1109 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
1110
1111 r = __dev_status(hc->md, param);
Jeff Mahoney7ec75f22006-06-26 00:27:24 -07001112 md = hc->md;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113 up_write(&_hash_lock);
Jeff Mahoney7ec75f22006-06-26 00:27:24 -07001114 dm_put(md);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001115 return r;
1116}
1117
1118/*
1119 * Retrieves a list of devices used by a particular dm device.
1120 */
1121static void retrieve_deps(struct dm_table *table,
1122 struct dm_ioctl *param, size_t param_size)
1123{
1124 unsigned int count = 0;
1125 struct list_head *tmp;
1126 size_t len, needed;
1127 struct dm_dev *dd;
1128 struct dm_target_deps *deps;
1129
1130 deps = get_result_buffer(param, param_size, &len);
1131
1132 /*
1133 * Count the devices.
1134 */
1135 list_for_each (tmp, dm_table_get_devices(table))
1136 count++;
1137
1138 /*
1139 * Check we have enough space.
1140 */
1141 needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
1142 if (len < needed) {
1143 param->flags |= DM_BUFFER_FULL_FLAG;
1144 return;
1145 }
1146
1147 /*
1148 * Fill in the devices.
1149 */
1150 deps->count = count;
1151 count = 0;
1152 list_for_each_entry (dd, dm_table_get_devices(table), list)
1153 deps->dev[count++] = huge_encode_dev(dd->bdev->bd_dev);
1154
1155 param->data_size = param->data_start + needed;
1156}
1157
1158static int table_deps(struct dm_ioctl *param, size_t param_size)
1159{
1160 int r = 0;
1161 struct mapped_device *md;
1162 struct dm_table *table;
1163
1164 md = find_device(param);
1165 if (!md)
1166 return -ENXIO;
1167
1168 r = __dev_status(md, param);
1169 if (r)
1170 goto out;
1171
1172 table = dm_get_table(md);
1173 if (table) {
1174 retrieve_deps(table, param, param_size);
1175 dm_table_put(table);
1176 }
1177
1178 out:
1179 dm_put(md);
1180 return r;
1181}
1182
1183/*
1184 * Return the status of a device as a text string for each
1185 * target.
1186 */
1187static int table_status(struct dm_ioctl *param, size_t param_size)
1188{
1189 int r;
1190 struct mapped_device *md;
1191 struct dm_table *table;
1192
1193 md = find_device(param);
1194 if (!md)
1195 return -ENXIO;
1196
1197 r = __dev_status(md, param);
1198 if (r)
1199 goto out;
1200
1201 table = dm_get_table(md);
1202 if (table) {
1203 retrieve_status(table, param, param_size);
1204 dm_table_put(table);
1205 }
1206
1207 out:
1208 dm_put(md);
1209 return r;
1210}
1211
1212/*
1213 * Pass a message to the target that's at the supplied device offset.
1214 */
1215static int target_message(struct dm_ioctl *param, size_t param_size)
1216{
1217 int r, argc;
1218 char **argv;
1219 struct mapped_device *md;
1220 struct dm_table *table;
1221 struct dm_target *ti;
1222 struct dm_target_msg *tmsg = (void *) param + param->data_start;
1223
1224 md = find_device(param);
1225 if (!md)
1226 return -ENXIO;
1227
1228 r = __dev_status(md, param);
1229 if (r)
1230 goto out;
1231
1232 if (tmsg < (struct dm_target_msg *) (param + 1) ||
1233 invalid_str(tmsg->message, (void *) param + param_size)) {
1234 DMWARN("Invalid target message parameters.");
1235 r = -EINVAL;
1236 goto out;
1237 }
1238
1239 r = dm_split_args(&argc, &argv, tmsg->message);
1240 if (r) {
1241 DMWARN("Failed to split target message parameters");
1242 goto out;
1243 }
1244
1245 table = dm_get_table(md);
1246 if (!table)
1247 goto out_argv;
1248
1249 if (tmsg->sector >= dm_table_get_size(table)) {
1250 DMWARN("Target message sector outside device.");
1251 r = -EINVAL;
1252 goto out_table;
1253 }
1254
1255 ti = dm_table_find_target(table, tmsg->sector);
1256 if (ti->type->message)
1257 r = ti->type->message(ti, argc, argv);
1258 else {
1259 DMWARN("Target type does not support messages");
1260 r = -EINVAL;
1261 }
1262
1263 out_table:
1264 dm_table_put(table);
1265 out_argv:
1266 kfree(argv);
1267 out:
1268 param->data_size = 0;
1269 dm_put(md);
1270 return r;
1271}
1272
1273/*-----------------------------------------------------------------
1274 * Implementation of open/close/ioctl on the special char
1275 * device.
1276 *---------------------------------------------------------------*/
1277static ioctl_fn lookup_ioctl(unsigned int cmd)
1278{
1279 static struct {
1280 int cmd;
1281 ioctl_fn fn;
1282 } _ioctls[] = {
1283 {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
1284 {DM_REMOVE_ALL_CMD, remove_all},
1285 {DM_LIST_DEVICES_CMD, list_devices},
1286
1287 {DM_DEV_CREATE_CMD, dev_create},
1288 {DM_DEV_REMOVE_CMD, dev_remove},
1289 {DM_DEV_RENAME_CMD, dev_rename},
1290 {DM_DEV_SUSPEND_CMD, dev_suspend},
1291 {DM_DEV_STATUS_CMD, dev_status},
1292 {DM_DEV_WAIT_CMD, dev_wait},
1293
1294 {DM_TABLE_LOAD_CMD, table_load},
1295 {DM_TABLE_CLEAR_CMD, table_clear},
1296 {DM_TABLE_DEPS_CMD, table_deps},
1297 {DM_TABLE_STATUS_CMD, table_status},
1298
1299 {DM_LIST_VERSIONS_CMD, list_versions},
1300
Darrick J. Wong3ac51e72006-03-27 01:17:54 -08001301 {DM_TARGET_MSG_CMD, target_message},
1302 {DM_DEV_SET_GEOMETRY_CMD, dev_set_geometry}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303 };
1304
1305 return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
1306}
1307
1308/*
1309 * As well as checking the version compatibility this always
1310 * copies the kernel interface version out.
1311 */
1312static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
1313{
1314 uint32_t version[3];
1315 int r = 0;
1316
1317 if (copy_from_user(version, user->version, sizeof(version)))
1318 return -EFAULT;
1319
1320 if ((DM_VERSION_MAJOR != version[0]) ||
1321 (DM_VERSION_MINOR < version[1])) {
1322 DMWARN("ioctl interface mismatch: "
1323 "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
1324 DM_VERSION_MAJOR, DM_VERSION_MINOR,
1325 DM_VERSION_PATCHLEVEL,
1326 version[0], version[1], version[2], cmd);
1327 r = -EINVAL;
1328 }
1329
1330 /*
1331 * Fill in the kernel version.
1332 */
1333 version[0] = DM_VERSION_MAJOR;
1334 version[1] = DM_VERSION_MINOR;
1335 version[2] = DM_VERSION_PATCHLEVEL;
1336 if (copy_to_user(user->version, version, sizeof(version)))
1337 return -EFAULT;
1338
1339 return r;
1340}
1341
1342static void free_params(struct dm_ioctl *param)
1343{
1344 vfree(param);
1345}
1346
1347static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
1348{
1349 struct dm_ioctl tmp, *dmi;
1350
1351 if (copy_from_user(&tmp, user, sizeof(tmp)))
1352 return -EFAULT;
1353
1354 if (tmp.data_size < sizeof(tmp))
1355 return -EINVAL;
1356
1357 dmi = (struct dm_ioctl *) vmalloc(tmp.data_size);
1358 if (!dmi)
1359 return -ENOMEM;
1360
1361 if (copy_from_user(dmi, user, tmp.data_size)) {
1362 vfree(dmi);
1363 return -EFAULT;
1364 }
1365
1366 *param = dmi;
1367 return 0;
1368}
1369
1370static int validate_params(uint cmd, struct dm_ioctl *param)
1371{
1372 /* Always clear this flag */
1373 param->flags &= ~DM_BUFFER_FULL_FLAG;
1374
1375 /* Ignores parameters */
1376 if (cmd == DM_REMOVE_ALL_CMD ||
1377 cmd == DM_LIST_DEVICES_CMD ||
1378 cmd == DM_LIST_VERSIONS_CMD)
1379 return 0;
1380
1381 if ((cmd == DM_DEV_CREATE_CMD)) {
1382 if (!*param->name) {
1383 DMWARN("name not supplied when creating device");
1384 return -EINVAL;
1385 }
1386 } else if ((*param->uuid && *param->name)) {
1387 DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
1388 return -EINVAL;
1389 }
1390
1391 /* Ensure strings are terminated */
1392 param->name[DM_NAME_LEN - 1] = '\0';
1393 param->uuid[DM_UUID_LEN - 1] = '\0';
1394
1395 return 0;
1396}
1397
1398static int ctl_ioctl(struct inode *inode, struct file *file,
1399 uint command, ulong u)
1400{
1401 int r = 0;
1402 unsigned int cmd;
1403 struct dm_ioctl *param;
1404 struct dm_ioctl __user *user = (struct dm_ioctl __user *) u;
1405 ioctl_fn fn = NULL;
1406 size_t param_size;
1407
1408 /* only root can play with this */
1409 if (!capable(CAP_SYS_ADMIN))
1410 return -EACCES;
1411
1412 if (_IOC_TYPE(command) != DM_IOCTL)
1413 return -ENOTTY;
1414
1415 cmd = _IOC_NR(command);
1416
1417 /*
1418 * Check the interface version passed in. This also
1419 * writes out the kernel's interface version.
1420 */
1421 r = check_version(cmd, user);
1422 if (r)
1423 return r;
1424
1425 /*
1426 * Nothing more to do for the version command.
1427 */
1428 if (cmd == DM_VERSION_CMD)
1429 return 0;
1430
1431 fn = lookup_ioctl(cmd);
1432 if (!fn) {
1433 DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
1434 return -ENOTTY;
1435 }
1436
1437 /*
1438 * Trying to avoid low memory issues when a device is
1439 * suspended.
1440 */
1441 current->flags |= PF_MEMALLOC;
1442
1443 /*
1444 * Copy the parameters into kernel space.
1445 */
1446 r = copy_params(user, &param);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447
Alasdair G Kergondab6a422006-02-01 03:04:52 -08001448 current->flags &= ~PF_MEMALLOC;
1449
1450 if (r)
1451 return r;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001452
1453 r = validate_params(cmd, param);
1454 if (r)
1455 goto out;
1456
1457 param_size = param->data_size;
1458 param->data_size = sizeof(*param);
1459 r = fn(param, param_size);
1460
1461 /*
1462 * Copy the results back to userland.
1463 */
1464 if (!r && copy_to_user(user, param, param->data_size))
1465 r = -EFAULT;
1466
1467 out:
1468 free_params(param);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469 return r;
1470}
1471
1472static struct file_operations _ctl_fops = {
1473 .ioctl = ctl_ioctl,
1474 .owner = THIS_MODULE,
1475};
1476
1477static struct miscdevice _dm_misc = {
1478 .minor = MISC_DYNAMIC_MINOR,
1479 .name = DM_NAME,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480 .fops = &_ctl_fops
1481};
1482
1483/*
1484 * Create misc character device and link to DM_DIR/control.
1485 */
1486int __init dm_interface_init(void)
1487{
1488 int r;
1489
1490 r = dm_hash_init();
1491 if (r)
1492 return r;
1493
1494 r = misc_register(&_dm_misc);
1495 if (r) {
1496 DMERR("misc_register failed for control device");
1497 dm_hash_exit();
1498 return r;
1499 }
1500
1501 DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
1502 DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
1503 DM_DRIVER_EMAIL);
1504 return 0;
1505}
1506
1507void dm_interface_exit(void)
1508{
1509 if (misc_deregister(&_dm_misc) < 0)
1510 DMERR("misc_deregister failed for control device");
1511
1512 dm_hash_exit();
1513}