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[PATCH] W1: w1_netlink: New init/fini netlink callbacks.
[linux-2.6/verdex.git] / drivers / md / dm-ioctl.c
blob200a0688f717c76759c1165cde20652ad14d07f7
1 /*
2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
3 * Copyright (C) 2004 - 2005 Red Hat, Inc. All rights reserved.
4 *
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>
16 #include <linux/devfs_fs_kernel.h>
17 #include <linux/dm-ioctl.h>
18
19 #include <asm/uaccess.h>
20
21 #define DM_DRIVER_EMAIL "dm-devel@redhat.com"
22
23 /*-----------------------------------------------------------------
24 * The ioctl interface needs to be able to look up devices by
25 * name or uuid.
26 *---------------------------------------------------------------*/
27 struct hash_cell {
28 struct list_head name_list;
29 struct list_head uuid_list;
30
31 char *name;
32 char *uuid;
33 struct mapped_device *md;
34 struct dm_table *new_map;
35 };
36
37 struct vers_iter {
38 size_t param_size;
39 struct dm_target_versions *vers, *old_vers;
40 char *end;
41 uint32_t flags;
42 };
43
44
45 #define NUM_BUCKETS 64
46 #define MASK_BUCKETS (NUM_BUCKETS - 1)
47 static struct list_head _name_buckets[NUM_BUCKETS];
48 static struct list_head _uuid_buckets[NUM_BUCKETS];
49
50 static void dm_hash_remove_all(void);
51
52 /*
53 * Guards access to both hash tables.
54 */
55 static DECLARE_RWSEM(_hash_lock);
56
57 static void init_buckets(struct list_head *buckets)
58 {
59 unsigned int i;
60
61 for (i = 0; i < NUM_BUCKETS; i++)
62 INIT_LIST_HEAD(buckets + i);
63 }
64
65 static int dm_hash_init(void)
66 {
67 init_buckets(_name_buckets);
68 init_buckets(_uuid_buckets);
69 devfs_mk_dir(DM_DIR);
70 return 0;
71 }
72
73 static void dm_hash_exit(void)
74 {
75 dm_hash_remove_all();
76 devfs_remove(DM_DIR);
77 }
78
79 /*-----------------------------------------------------------------
80 * Hash function:
81 * We're not really concerned with the str hash function being
82 * fast since it's only used by the ioctl interface.
83 *---------------------------------------------------------------*/
84 static unsigned int hash_str(const char *str)
85 {
86 const unsigned int hash_mult = 2654435387U;
87 unsigned int h = 0;
88
89 while (*str)
90 h = (h + (unsigned int) *str++) * hash_mult;
91
92 return h & MASK_BUCKETS;
93 }
94
95 /*-----------------------------------------------------------------
96 * Code for looking up a device by name
97 *---------------------------------------------------------------*/
98 static struct hash_cell *__get_name_cell(const char *str)
99 {
100 struct hash_cell *hc;
101 unsigned int h = hash_str(str);
102
103 list_for_each_entry (hc, _name_buckets + h, name_list)
104 if (!strcmp(hc->name, str))
105 return hc;
106
107 return NULL;
108 }
109
110 static struct hash_cell *__get_uuid_cell(const char *str)
111 {
112 struct hash_cell *hc;
113 unsigned int h = hash_str(str);
114
115 list_for_each_entry (hc, _uuid_buckets + h, uuid_list)
116 if (!strcmp(hc->uuid, str))
117 return hc;
118
119 return NULL;
120 }
121
122 /*-----------------------------------------------------------------
123 * Inserting, removing and renaming a device.
124 *---------------------------------------------------------------*/
125 static struct hash_cell *alloc_cell(const char *name, const char *uuid,
126 struct mapped_device *md)
127 {
128 struct hash_cell *hc;
129
130 hc = kmalloc(sizeof(*hc), GFP_KERNEL);
131 if (!hc)
132 return NULL;
133
134 hc->name = kstrdup(name, GFP_KERNEL);
135 if (!hc->name) {
136 kfree(hc);
137 return NULL;
138 }
139
140 if (!uuid)
141 hc->uuid = NULL;
142
143 else {
144 hc->uuid = kstrdup(uuid, GFP_KERNEL);
145 if (!hc->uuid) {
146 kfree(hc->name);
147 kfree(hc);
148 return NULL;
149 }
150 }
151
152 INIT_LIST_HEAD(&hc->name_list);
153 INIT_LIST_HEAD(&hc->uuid_list);
154 hc->md = md;
155 hc->new_map = NULL;
156 return hc;
157 }
158
159 static void free_cell(struct hash_cell *hc)
160 {
161 if (hc) {
162 kfree(hc->name);
163 kfree(hc->uuid);
164 kfree(hc);
165 }
166 }
167
168 /*
169 * devfs stuff.
170 */
171 static int register_with_devfs(struct hash_cell *hc)
172 {
173 struct gendisk *disk = dm_disk(hc->md);
174
175 devfs_mk_bdev(MKDEV(disk->major, disk->first_minor),
176 S_IFBLK | S_IRUSR | S_IWUSR | S_IRGRP,
177 DM_DIR "/%s", hc->name);
178 return 0;
179 }
180
181 static int unregister_with_devfs(struct hash_cell *hc)
182 {
183 devfs_remove(DM_DIR"/%s", hc->name);
184 return 0;
185 }
186
187 /*
188 * The kdev_t and uuid of a device can never change once it is
189 * initially inserted.
190 */
191 static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md)
192 {
193 struct hash_cell *cell;
194
195 /*
196 * Allocate the new cells.
197 */
198 cell = alloc_cell(name, uuid, md);
199 if (!cell)
200 return -ENOMEM;
201
202 /*
203 * Insert the cell into both hash tables.
204 */
205 down_write(&_hash_lock);
206 if (__get_name_cell(name))
207 goto bad;
208
209 list_add(&cell->name_list, _name_buckets + hash_str(name));
210
211 if (uuid) {
212 if (__get_uuid_cell(uuid)) {
213 list_del(&cell->name_list);
214 goto bad;
215 }
216 list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
217 }
218 register_with_devfs(cell);
219 dm_get(md);
220 dm_set_mdptr(md, cell);
221 up_write(&_hash_lock);
222
223 return 0;
224
225 bad:
226 up_write(&_hash_lock);
227 free_cell(cell);
228 return -EBUSY;
229 }
230
231 static void __hash_remove(struct hash_cell *hc)
232 {
233 /* remove from the dev hash */
234 list_del(&hc->uuid_list);
235 list_del(&hc->name_list);
236 unregister_with_devfs(hc);
237 dm_set_mdptr(hc->md, NULL);
238 dm_put(hc->md);
239 if (hc->new_map)
240 dm_table_put(hc->new_map);
241 free_cell(hc);
242 }
243
244 static void dm_hash_remove_all(void)
245 {
246 int i;
247 struct hash_cell *hc;
248 struct list_head *tmp, *n;
249
250 down_write(&_hash_lock);
251 for (i = 0; i < NUM_BUCKETS; i++) {
252 list_for_each_safe (tmp, n, _name_buckets + i) {
253 hc = list_entry(tmp, struct hash_cell, name_list);
254 __hash_remove(hc);
255 }
256 }
257 up_write(&_hash_lock);
258 }
259
260 static int dm_hash_rename(const char *old, const char *new)
261 {
262 char *new_name, *old_name;
263 struct hash_cell *hc;
264
265 /*
266 * duplicate new.
267 */
268 new_name = kstrdup(new, GFP_KERNEL);
269 if (!new_name)
270 return -ENOMEM;
271
272 down_write(&_hash_lock);
273
274 /*
275 * Is new free ?
276 */
277 hc = __get_name_cell(new);
278 if (hc) {
279 DMWARN("asked to rename to an already existing name %s -> %s",
280 old, new);
281 up_write(&_hash_lock);
282 kfree(new_name);
283 return -EBUSY;
284 }
285
286 /*
287 * Is there such a device as 'old' ?
288 */
289 hc = __get_name_cell(old);
290 if (!hc) {
291 DMWARN("asked to rename a non existent device %s -> %s",
292 old, new);
293 up_write(&_hash_lock);
294 kfree(new_name);
295 return -ENXIO;
296 }
297
298 /*
299 * rename and move the name cell.
300 */
301 unregister_with_devfs(hc);
302
303 list_del(&hc->name_list);
304 old_name = hc->name;
305 hc->name = new_name;
306 list_add(&hc->name_list, _name_buckets + hash_str(new_name));
307
308 /* rename the device node in devfs */
309 register_with_devfs(hc);
310
311 up_write(&_hash_lock);
312 kfree(old_name);
313 return 0;
314 }
315
316 /*-----------------------------------------------------------------
317 * Implementation of the ioctl commands
318 *---------------------------------------------------------------*/
319 /*
320 * All the ioctl commands get dispatched to functions with this
321 * prototype.
322 */
323 typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
324
325 static int remove_all(struct dm_ioctl *param, size_t param_size)
326 {
327 dm_hash_remove_all();
328 param->data_size = 0;
329 return 0;
330 }
331
332 /*
333 * Round up the ptr to an 8-byte boundary.
334 */
335 #define ALIGN_MASK 7
336 static inline void *align_ptr(void *ptr)
337 {
338 return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
339 }
340
341 /*
342 * Retrieves the data payload buffer from an already allocated
343 * struct dm_ioctl.
344 */
345 static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
346 size_t *len)
347 {
348 param->data_start = align_ptr(param + 1) - (void *) param;
349
350 if (param->data_start < param_size)
351 *len = param_size - param->data_start;
352 else
353 *len = 0;
354
355 return ((void *) param) + param->data_start;
356 }
357
358 static int list_devices(struct dm_ioctl *param, size_t param_size)
359 {
360 unsigned int i;
361 struct hash_cell *hc;
362 size_t len, needed = 0;
363 struct gendisk *disk;
364 struct dm_name_list *nl, *old_nl = NULL;
365
366 down_write(&_hash_lock);
367
368 /*
369 * Loop through all the devices working out how much
370 * space we need.
371 */
372 for (i = 0; i < NUM_BUCKETS; i++) {
373 list_for_each_entry (hc, _name_buckets + i, name_list) {
374 needed += sizeof(struct dm_name_list);
375 needed += strlen(hc->name) + 1;
376 needed += ALIGN_MASK;
377 }
378 }
379
380 /*
381 * Grab our output buffer.
382 */
383 nl = get_result_buffer(param, param_size, &len);
384 if (len < needed) {
385 param->flags |= DM_BUFFER_FULL_FLAG;
386 goto out;
387 }
388 param->data_size = param->data_start + needed;
389
390 nl->dev = 0; /* Flags no data */
391
392 /*
393 * Now loop through filling out the names.
394 */
395 for (i = 0; i < NUM_BUCKETS; i++) {
396 list_for_each_entry (hc, _name_buckets + i, name_list) {
397 if (old_nl)
398 old_nl->next = (uint32_t) ((void *) nl -
399 (void *) old_nl);
400 disk = dm_disk(hc->md);
401 nl->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
402 nl->next = 0;
403 strcpy(nl->name, hc->name);
404
405 old_nl = nl;
406 nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
407 }
408 }
409
410 out:
411 up_write(&_hash_lock);
412 return 0;
413 }
414
415 static void list_version_get_needed(struct target_type *tt, void *needed_param)
416 {
417 size_t *needed = needed_param;
418
419 *needed += strlen(tt->name);
420 *needed += sizeof(tt->version);
421 *needed += ALIGN_MASK;
422 }
423
424 static void list_version_get_info(struct target_type *tt, void *param)
425 {
426 struct vers_iter *info = param;
427
428 /* Check space - it might have changed since the first iteration */
429 if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
430 info->end) {
431
432 info->flags = DM_BUFFER_FULL_FLAG;
433 return;
434 }
435
436 if (info->old_vers)
437 info->old_vers->next = (uint32_t) ((void *)info->vers -
438 (void *)info->old_vers);
439 info->vers->version[0] = tt->version[0];
440 info->vers->version[1] = tt->version[1];
441 info->vers->version[2] = tt->version[2];
442 info->vers->next = 0;
443 strcpy(info->vers->name, tt->name);
444
445 info->old_vers = info->vers;
446 info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
447 }
448
449 static int list_versions(struct dm_ioctl *param, size_t param_size)
450 {
451 size_t len, needed = 0;
452 struct dm_target_versions *vers;
453 struct vers_iter iter_info;
454
455 /*
456 * Loop through all the devices working out how much
457 * space we need.
458 */
459 dm_target_iterate(list_version_get_needed, &needed);
460
461 /*
462 * Grab our output buffer.
463 */
464 vers = get_result_buffer(param, param_size, &len);
465 if (len < needed) {
466 param->flags |= DM_BUFFER_FULL_FLAG;
467 goto out;
468 }
469 param->data_size = param->data_start + needed;
470
471 iter_info.param_size = param_size;
472 iter_info.old_vers = NULL;
473 iter_info.vers = vers;
474 iter_info.flags = 0;
475 iter_info.end = (char *)vers+len;
476
477 /*
478 * Now loop through filling out the names & versions.
479 */
480 dm_target_iterate(list_version_get_info, &iter_info);
481 param->flags |= iter_info.flags;
482
483 out:
484 return 0;
485 }
486
487
488
489 static int check_name(const char *name)
490 {
491 if (strchr(name, '/')) {
492 DMWARN("invalid device name");
493 return -EINVAL;
494 }
495
496 return 0;
497 }
498
499 /*
500 * Fills in a dm_ioctl structure, ready for sending back to
501 * userland.
502 */
503 static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
504 {
505 struct gendisk *disk = dm_disk(md);
506 struct dm_table *table;
507 struct block_device *bdev;
508
509 param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
510 DM_ACTIVE_PRESENT_FLAG);
511
512 if (dm_suspended(md))
513 param->flags |= DM_SUSPEND_FLAG;
514
515 param->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
516
517 if (!(param->flags & DM_SKIP_BDGET_FLAG)) {
518 bdev = bdget_disk(disk, 0);
519 if (!bdev)
520 return -ENXIO;
521
522 /*
523 * Yes, this will be out of date by the time it gets back
524 * to userland, but it is still very useful for
525 * debugging.
526 */
527 param->open_count = bdev->bd_openers;
528 bdput(bdev);
529 } else
530 param->open_count = -1;
531
532 if (disk->policy)
533 param->flags |= DM_READONLY_FLAG;
534
535 param->event_nr = dm_get_event_nr(md);
536
537 table = dm_get_table(md);
538 if (table) {
539 param->flags |= DM_ACTIVE_PRESENT_FLAG;
540 param->target_count = dm_table_get_num_targets(table);
541 dm_table_put(table);
542 } else
543 param->target_count = 0;
544
545 return 0;
546 }
547
548 static int dev_create(struct dm_ioctl *param, size_t param_size)
549 {
550 int r;
551 struct mapped_device *md;
552
553 r = check_name(param->name);
554 if (r)
555 return r;
556
557 if (param->flags & DM_PERSISTENT_DEV_FLAG)
558 r = dm_create_with_minor(MINOR(huge_decode_dev(param->dev)), &md);
559 else
560 r = dm_create(&md);
561
562 if (r)
563 return r;
564
565 r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
566 if (r) {
567 dm_put(md);
568 return r;
569 }
570
571 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
572
573 r = __dev_status(md, param);
574 dm_put(md);
575
576 return r;
577 }
578
579 /*
580 * Always use UUID for lookups if it's present, otherwise use name or dev.
581 */
582 static inline struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
583 {
584 if (*param->uuid)
585 return __get_uuid_cell(param->uuid);
586 else if (*param->name)
587 return __get_name_cell(param->name);
588 else
589 return dm_get_mdptr(huge_decode_dev(param->dev));
590 }
591
592 static inline struct mapped_device *find_device(struct dm_ioctl *param)
593 {
594 struct hash_cell *hc;
595 struct mapped_device *md = NULL;
596
597 down_read(&_hash_lock);
598 hc = __find_device_hash_cell(param);
599 if (hc) {
600 md = hc->md;
601 dm_get(md);
602
603 /*
604 * Sneakily write in both the name and the uuid
605 * while we have the cell.
606 */
607 strncpy(param->name, hc->name, sizeof(param->name));
608 if (hc->uuid)
609 strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
610 else
611 param->uuid[0] = '\0';
612
613 if (hc->new_map)
614 param->flags |= DM_INACTIVE_PRESENT_FLAG;
615 else
616 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
617 }
618 up_read(&_hash_lock);
619
620 return md;
621 }
622
623 static int dev_remove(struct dm_ioctl *param, size_t param_size)
624 {
625 struct hash_cell *hc;
626
627 down_write(&_hash_lock);
628 hc = __find_device_hash_cell(param);
629
630 if (!hc) {
631 DMWARN("device doesn't appear to be in the dev hash table.");
632 up_write(&_hash_lock);
633 return -ENXIO;
634 }
635
636 __hash_remove(hc);
637 up_write(&_hash_lock);
638 param->data_size = 0;
639 return 0;
640 }
641
642 /*
643 * Check a string doesn't overrun the chunk of
644 * memory we copied from userland.
645 */
646 static int invalid_str(char *str, void *end)
647 {
648 while ((void *) str < end)
649 if (!*str++)
650 return 0;
651
652 return -EINVAL;
653 }
654
655 static int dev_rename(struct dm_ioctl *param, size_t param_size)
656 {
657 int r;
658 char *new_name = (char *) param + param->data_start;
659
660 if (new_name < (char *) (param + 1) ||
661 invalid_str(new_name, (void *) param + param_size)) {
662 DMWARN("Invalid new logical volume name supplied.");
663 return -EINVAL;
664 }
665
666 r = check_name(new_name);
667 if (r)
668 return r;
669
670 param->data_size = 0;
671 return dm_hash_rename(param->name, new_name);
672 }
673
674 static int do_suspend(struct dm_ioctl *param)
675 {
676 int r = 0;
677 struct mapped_device *md;
678
679 md = find_device(param);
680 if (!md)
681 return -ENXIO;
682
683 if (!dm_suspended(md))
684 r = dm_suspend(md);
685
686 if (!r)
687 r = __dev_status(md, param);
688
689 dm_put(md);
690 return r;
691 }
692
693 static int do_resume(struct dm_ioctl *param)
694 {
695 int r = 0;
696 struct hash_cell *hc;
697 struct mapped_device *md;
698 struct dm_table *new_map;
699
700 down_write(&_hash_lock);
701
702 hc = __find_device_hash_cell(param);
703 if (!hc) {
704 DMWARN("device doesn't appear to be in the dev hash table.");
705 up_write(&_hash_lock);
706 return -ENXIO;
707 }
708
709 md = hc->md;
710 dm_get(md);
711
712 new_map = hc->new_map;
713 hc->new_map = NULL;
714 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
715
716 up_write(&_hash_lock);
717
718 /* Do we need to load a new map ? */
719 if (new_map) {
720 /* Suspend if it isn't already suspended */
721 if (!dm_suspended(md))
722 dm_suspend(md);
723
724 r = dm_swap_table(md, new_map);
725 if (r) {
726 dm_put(md);
727 dm_table_put(new_map);
728 return r;
729 }
730
731 if (dm_table_get_mode(new_map) & FMODE_WRITE)
732 set_disk_ro(dm_disk(md), 0);
733 else
734 set_disk_ro(dm_disk(md), 1);
735
736 dm_table_put(new_map);
737 }
738
739 if (dm_suspended(md))
740 r = dm_resume(md);
741
742 if (!r)
743 r = __dev_status(md, param);
744
745 dm_put(md);
746 return r;
747 }
748
749 /*
750 * Set or unset the suspension state of a device.
751 * If the device already is in the requested state we just return its status.
752 */
753 static int dev_suspend(struct dm_ioctl *param, size_t param_size)
754 {
755 if (param->flags & DM_SUSPEND_FLAG)
756 return do_suspend(param);
757
758 return do_resume(param);
759 }
760
761 /*
762 * Copies device info back to user space, used by
763 * the create and info ioctls.
764 */
765 static int dev_status(struct dm_ioctl *param, size_t param_size)
766 {
767 int r;
768 struct mapped_device *md;
769
770 md = find_device(param);
771 if (!md)
772 return -ENXIO;
773
774 r = __dev_status(md, param);
775 dm_put(md);
776 return r;
777 }
778
779 /*
780 * Build up the status struct for each target
781 */
782 static void retrieve_status(struct dm_table *table,
783 struct dm_ioctl *param, size_t param_size)
784 {
785 unsigned int i, num_targets;
786 struct dm_target_spec *spec;
787 char *outbuf, *outptr;
788 status_type_t type;
789 size_t remaining, len, used = 0;
790
791 outptr = outbuf = get_result_buffer(param, param_size, &len);
792
793 if (param->flags & DM_STATUS_TABLE_FLAG)
794 type = STATUSTYPE_TABLE;
795 else
796 type = STATUSTYPE_INFO;
797
798 /* Get all the target info */
799 num_targets = dm_table_get_num_targets(table);
800 for (i = 0; i < num_targets; i++) {
801 struct dm_target *ti = dm_table_get_target(table, i);
802
803 remaining = len - (outptr - outbuf);
804 if (remaining <= sizeof(struct dm_target_spec)) {
805 param->flags |= DM_BUFFER_FULL_FLAG;
806 break;
807 }
808
809 spec = (struct dm_target_spec *) outptr;
810
811 spec->status = 0;
812 spec->sector_start = ti->begin;
813 spec->length = ti->len;
814 strncpy(spec->target_type, ti->type->name,
815 sizeof(spec->target_type));
816
817 outptr += sizeof(struct dm_target_spec);
818 remaining = len - (outptr - outbuf);
819 if (remaining <= 0) {
820 param->flags |= DM_BUFFER_FULL_FLAG;
821 break;
822 }
823
824 /* Get the status/table string from the target driver */
825 if (ti->type->status) {
826 if (ti->type->status(ti, type, outptr, remaining)) {
827 param->flags |= DM_BUFFER_FULL_FLAG;
828 break;
829 }
830 } else
831 outptr[0] = '\0';
832
833 outptr += strlen(outptr) + 1;
834 used = param->data_start + (outptr - outbuf);
835
836 outptr = align_ptr(outptr);
837 spec->next = outptr - outbuf;
838 }
839
840 if (used)
841 param->data_size = used;
842
843 param->target_count = num_targets;
844 }
845
846 /*
847 * Wait for a device to report an event
848 */
849 static int dev_wait(struct dm_ioctl *param, size_t param_size)
850 {
851 int r;
852 struct mapped_device *md;
853 struct dm_table *table;
854
855 md = find_device(param);
856 if (!md)
857 return -ENXIO;
858
859 /*
860 * Wait for a notification event
861 */
862 if (dm_wait_event(md, param->event_nr)) {
863 r = -ERESTARTSYS;
864 goto out;
865 }
866
867 /*
868 * The userland program is going to want to know what
869 * changed to trigger the event, so we may as well tell
870 * him and save an ioctl.
871 */
872 r = __dev_status(md, param);
873 if (r)
874 goto out;
875
876 table = dm_get_table(md);
877 if (table) {
878 retrieve_status(table, param, param_size);
879 dm_table_put(table);
880 }
881
882 out:
883 dm_put(md);
884 return r;
885 }
886
887 static inline int get_mode(struct dm_ioctl *param)
888 {
889 int mode = FMODE_READ | FMODE_WRITE;
890
891 if (param->flags & DM_READONLY_FLAG)
892 mode = FMODE_READ;
893
894 return mode;
895 }
896
897 static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
898 struct dm_target_spec **spec, char **target_params)
899 {
900 *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
901 *target_params = (char *) (*spec + 1);
902
903 if (*spec < (last + 1))
904 return -EINVAL;
905
906 return invalid_str(*target_params, end);
907 }
908
909 static int populate_table(struct dm_table *table,
910 struct dm_ioctl *param, size_t param_size)
911 {
912 int r;
913 unsigned int i = 0;
914 struct dm_target_spec *spec = (struct dm_target_spec *) param;
915 uint32_t next = param->data_start;
916 void *end = (void *) param + param_size;
917 char *target_params;
918
919 if (!param->target_count) {
920 DMWARN("populate_table: no targets specified");
921 return -EINVAL;
922 }
923
924 for (i = 0; i < param->target_count; i++) {
925
926 r = next_target(spec, next, end, &spec, &target_params);
927 if (r) {
928 DMWARN("unable to find target");
929 return r;
930 }
931
932 r = dm_table_add_target(table, spec->target_type,
933 (sector_t) spec->sector_start,
934 (sector_t) spec->length,
935 target_params);
936 if (r) {
937 DMWARN("error adding target to table");
938 return r;
939 }
940
941 next = spec->next;
942 }
943
944 return dm_table_complete(table);
945 }
946
947 static int table_load(struct dm_ioctl *param, size_t param_size)
948 {
949 int r;
950 struct hash_cell *hc;
951 struct dm_table *t;
952
953 r = dm_table_create(&t, get_mode(param), param->target_count);
954 if (r)
955 return r;
956
957 r = populate_table(t, param, param_size);
958 if (r) {
959 dm_table_put(t);
960 return r;
961 }
962
963 down_write(&_hash_lock);
964 hc = __find_device_hash_cell(param);
965 if (!hc) {
966 DMWARN("device doesn't appear to be in the dev hash table.");
967 up_write(&_hash_lock);
968 return -ENXIO;
969 }
970
971 if (hc->new_map)
972 dm_table_put(hc->new_map);
973 hc->new_map = t;
974 param->flags |= DM_INACTIVE_PRESENT_FLAG;
975
976 r = __dev_status(hc->md, param);
977 up_write(&_hash_lock);
978 return r;
979 }
980
981 static int table_clear(struct dm_ioctl *param, size_t param_size)
982 {
983 int r;
984 struct hash_cell *hc;
985
986 down_write(&_hash_lock);
987
988 hc = __find_device_hash_cell(param);
989 if (!hc) {
990 DMWARN("device doesn't appear to be in the dev hash table.");
991 up_write(&_hash_lock);
992 return -ENXIO;
993 }
994
995 if (hc->new_map) {
996 dm_table_put(hc->new_map);
997 hc->new_map = NULL;
998 }
999
1000 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
1001
1002 r = __dev_status(hc->md, param);
1003 up_write(&_hash_lock);
1004 return r;
1005 }
1006
1007 /*
1008 * Retrieves a list of devices used by a particular dm device.
1009 */
1010 static void retrieve_deps(struct dm_table *table,
1011 struct dm_ioctl *param, size_t param_size)
1012 {
1013 unsigned int count = 0;
1014 struct list_head *tmp;
1015 size_t len, needed;
1016 struct dm_dev *dd;
1017 struct dm_target_deps *deps;
1018
1019 deps = get_result_buffer(param, param_size, &len);
1020
1021 /*
1022 * Count the devices.
1023 */
1024 list_for_each (tmp, dm_table_get_devices(table))
1025 count++;
1026
1027 /*
1028 * Check we have enough space.
1029 */
1030 needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
1031 if (len < needed) {
1032 param->flags |= DM_BUFFER_FULL_FLAG;
1033 return;
1034 }
1035
1036 /*
1037 * Fill in the devices.
1038 */
1039 deps->count = count;
1040 count = 0;
1041 list_for_each_entry (dd, dm_table_get_devices(table), list)
1042 deps->dev[count++] = huge_encode_dev(dd->bdev->bd_dev);
1043
1044 param->data_size = param->data_start + needed;
1045 }
1046
1047 static int table_deps(struct dm_ioctl *param, size_t param_size)
1048 {
1049 int r = 0;
1050 struct mapped_device *md;
1051 struct dm_table *table;
1052
1053 md = find_device(param);
1054 if (!md)
1055 return -ENXIO;
1056
1057 r = __dev_status(md, param);
1058 if (r)
1059 goto out;
1060
1061 table = dm_get_table(md);
1062 if (table) {
1063 retrieve_deps(table, param, param_size);
1064 dm_table_put(table);
1065 }
1066
1067 out:
1068 dm_put(md);
1069 return r;
1070 }
1071
1072 /*
1073 * Return the status of a device as a text string for each
1074 * target.
1075 */
1076 static int table_status(struct dm_ioctl *param, size_t param_size)
1077 {
1078 int r;
1079 struct mapped_device *md;
1080 struct dm_table *table;
1081
1082 md = find_device(param);
1083 if (!md)
1084 return -ENXIO;
1085
1086 r = __dev_status(md, param);
1087 if (r)
1088 goto out;
1089
1090 table = dm_get_table(md);
1091 if (table) {
1092 retrieve_status(table, param, param_size);
1093 dm_table_put(table);
1094 }
1095
1096 out:
1097 dm_put(md);
1098 return r;
1099 }
1100
1101 /*
1102 * Pass a message to the target that's at the supplied device offset.
1103 */
1104 static int target_message(struct dm_ioctl *param, size_t param_size)
1105 {
1106 int r, argc;
1107 char **argv;
1108 struct mapped_device *md;
1109 struct dm_table *table;
1110 struct dm_target *ti;
1111 struct dm_target_msg *tmsg = (void *) param + param->data_start;
1112
1113 md = find_device(param);
1114 if (!md)
1115 return -ENXIO;
1116
1117 r = __dev_status(md, param);
1118 if (r)
1119 goto out;
1120
1121 if (tmsg < (struct dm_target_msg *) (param + 1) ||
1122 invalid_str(tmsg->message, (void *) param + param_size)) {
1123 DMWARN("Invalid target message parameters.");
1124 r = -EINVAL;
1125 goto out;
1126 }
1127
1128 r = dm_split_args(&argc, &argv, tmsg->message);
1129 if (r) {
1130 DMWARN("Failed to split target message parameters");
1131 goto out;
1132 }
1133
1134 table = dm_get_table(md);
1135 if (!table)
1136 goto out_argv;
1137
1138 if (tmsg->sector >= dm_table_get_size(table)) {
1139 DMWARN("Target message sector outside device.");
1140 r = -EINVAL;
1141 goto out_table;
1142 }
1143
1144 ti = dm_table_find_target(table, tmsg->sector);
1145 if (ti->type->message)
1146 r = ti->type->message(ti, argc, argv);
1147 else {
1148 DMWARN("Target type does not support messages");
1149 r = -EINVAL;
1150 }
1151
1152 out_table:
1153 dm_table_put(table);
1154 out_argv:
1155 kfree(argv);
1156 out:
1157 param->data_size = 0;
1158 dm_put(md);
1159 return r;
1160 }
1161
1162 /*-----------------------------------------------------------------
1163 * Implementation of open/close/ioctl on the special char
1164 * device.
1165 *---------------------------------------------------------------*/
1166 static ioctl_fn lookup_ioctl(unsigned int cmd)
1167 {
1168 static struct {
1169 int cmd;
1170 ioctl_fn fn;
1171 } _ioctls[] = {
1172 {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
1173 {DM_REMOVE_ALL_CMD, remove_all},
1174 {DM_LIST_DEVICES_CMD, list_devices},
1175
1176 {DM_DEV_CREATE_CMD, dev_create},
1177 {DM_DEV_REMOVE_CMD, dev_remove},
1178 {DM_DEV_RENAME_CMD, dev_rename},
1179 {DM_DEV_SUSPEND_CMD, dev_suspend},
1180 {DM_DEV_STATUS_CMD, dev_status},
1181 {DM_DEV_WAIT_CMD, dev_wait},
1182
1183 {DM_TABLE_LOAD_CMD, table_load},
1184 {DM_TABLE_CLEAR_CMD, table_clear},
1185 {DM_TABLE_DEPS_CMD, table_deps},
1186 {DM_TABLE_STATUS_CMD, table_status},
1187
1188 {DM_LIST_VERSIONS_CMD, list_versions},
1189
1190 {DM_TARGET_MSG_CMD, target_message}
1191 };
1192
1193 return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
1194 }
1195
1196 /*
1197 * As well as checking the version compatibility this always
1198 * copies the kernel interface version out.
1199 */
1200 static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
1201 {
1202 uint32_t version[3];
1203 int r = 0;
1204
1205 if (copy_from_user(version, user->version, sizeof(version)))
1206 return -EFAULT;
1207
1208 if ((DM_VERSION_MAJOR != version[0]) ||
1209 (DM_VERSION_MINOR < version[1])) {
1210 DMWARN("ioctl interface mismatch: "
1211 "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
1212 DM_VERSION_MAJOR, DM_VERSION_MINOR,
1213 DM_VERSION_PATCHLEVEL,
1214 version[0], version[1], version[2], cmd);
1215 r = -EINVAL;
1216 }
1217
1218 /*
1219 * Fill in the kernel version.
1220 */
1221 version[0] = DM_VERSION_MAJOR;
1222 version[1] = DM_VERSION_MINOR;
1223 version[2] = DM_VERSION_PATCHLEVEL;
1224 if (copy_to_user(user->version, version, sizeof(version)))
1225 return -EFAULT;
1226
1227 return r;
1228 }
1229
1230 static void free_params(struct dm_ioctl *param)
1231 {
1232 vfree(param);
1233 }
1234
1235 static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
1236 {
1237 struct dm_ioctl tmp, *dmi;
1238
1239 if (copy_from_user(&tmp, user, sizeof(tmp)))
1240 return -EFAULT;
1241
1242 if (tmp.data_size < sizeof(tmp))
1243 return -EINVAL;
1244
1245 dmi = (struct dm_ioctl *) vmalloc(tmp.data_size);
1246 if (!dmi)
1247 return -ENOMEM;
1248
1249 if (copy_from_user(dmi, user, tmp.data_size)) {
1250 vfree(dmi);
1251 return -EFAULT;
1252 }
1253
1254 *param = dmi;
1255 return 0;
1256 }
1257
1258 static int validate_params(uint cmd, struct dm_ioctl *param)
1259 {
1260 /* Always clear this flag */
1261 param->flags &= ~DM_BUFFER_FULL_FLAG;
1262
1263 /* Ignores parameters */
1264 if (cmd == DM_REMOVE_ALL_CMD ||
1265 cmd == DM_LIST_DEVICES_CMD ||
1266 cmd == DM_LIST_VERSIONS_CMD)
1267 return 0;
1268
1269 if ((cmd == DM_DEV_CREATE_CMD)) {
1270 if (!*param->name) {
1271 DMWARN("name not supplied when creating device");
1272 return -EINVAL;
1273 }
1274 } else if ((*param->uuid && *param->name)) {
1275 DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
1276 return -EINVAL;
1277 }
1278
1279 /* Ensure strings are terminated */
1280 param->name[DM_NAME_LEN - 1] = '\0';
1281 param->uuid[DM_UUID_LEN - 1] = '\0';
1282
1283 return 0;
1284 }
1285
1286 static int ctl_ioctl(struct inode *inode, struct file *file,
1287 uint command, ulong u)
1288 {
1289 int r = 0;
1290 unsigned int cmd;
1291 struct dm_ioctl *param;
1292 struct dm_ioctl __user *user = (struct dm_ioctl __user *) u;
1293 ioctl_fn fn = NULL;
1294 size_t param_size;
1295
1296 /* only root can play with this */
1297 if (!capable(CAP_SYS_ADMIN))
1298 return -EACCES;
1299
1300 if (_IOC_TYPE(command) != DM_IOCTL)
1301 return -ENOTTY;
1302
1303 cmd = _IOC_NR(command);
1304
1305 /*
1306 * Check the interface version passed in. This also
1307 * writes out the kernel's interface version.
1308 */
1309 r = check_version(cmd, user);
1310 if (r)
1311 return r;
1312
1313 /*
1314 * Nothing more to do for the version command.
1315 */
1316 if (cmd == DM_VERSION_CMD)
1317 return 0;
1318
1319 fn = lookup_ioctl(cmd);
1320 if (!fn) {
1321 DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
1322 return -ENOTTY;
1323 }
1324
1325 /*
1326 * Trying to avoid low memory issues when a device is
1327 * suspended.
1328 */
1329 current->flags |= PF_MEMALLOC;
1330
1331 /*
1332 * Copy the parameters into kernel space.
1333 */
1334 r = copy_params(user, &param);
1335 if (r) {
1336 current->flags &= ~PF_MEMALLOC;
1337 return r;
1338 }
1339
1340 /*
1341 * FIXME: eventually we will remove the PF_MEMALLOC flag
1342 * here. However the tools still do nasty things like
1343 * 'load' while a device is suspended.
1344 */
1345
1346 r = validate_params(cmd, param);
1347 if (r)
1348 goto out;
1349
1350 param_size = param->data_size;
1351 param->data_size = sizeof(*param);
1352 r = fn(param, param_size);
1353
1354 /*
1355 * Copy the results back to userland.
1356 */
1357 if (!r && copy_to_user(user, param, param->data_size))
1358 r = -EFAULT;
1359
1360 out:
1361 free_params(param);
1362 current->flags &= ~PF_MEMALLOC;
1363 return r;
1364 }
1365
1366 static struct file_operations _ctl_fops = {
1367 .ioctl = ctl_ioctl,
1368 .owner = THIS_MODULE,
1369 };
1370
1371 static struct miscdevice _dm_misc = {
1372 .minor = MISC_DYNAMIC_MINOR,
1373 .name = DM_NAME,
1374 .devfs_name = "mapper/control",
1375 .fops = &_ctl_fops
1376 };
1377
1378 /*
1379 * Create misc character device and link to DM_DIR/control.
1380 */
1381 int __init dm_interface_init(void)
1382 {
1383 int r;
1384
1385 r = dm_hash_init();
1386 if (r)
1387 return r;
1388
1389 r = misc_register(&_dm_misc);
1390 if (r) {
1391 DMERR("misc_register failed for control device");
1392 dm_hash_exit();
1393 return r;
1394 }
1395
1396 DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
1397 DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
1398 DM_DRIVER_EMAIL);
1399 return 0;
1400 }
1401
1402 void dm_interface_exit(void)
1403 {
1404 if (misc_deregister(&_dm_misc) < 0)
1405 DMERR("misc_deregister failed for control device");
1406
1407 dm_hash_exit();
1408 }
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