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RPC: Do not block on skb allocation
[linux-2.6/verdex.git] / drivers / md / dm-ioctl.c
blob07d44e19536e5c42c12cc00f3b37f23f16a49dfb
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 struct dm_table *table;
234
235 /* remove from the dev hash */
236 list_del(&hc->uuid_list);
237 list_del(&hc->name_list);
238 unregister_with_devfs(hc);
239 dm_set_mdptr(hc->md, NULL);
240
241 table = dm_get_table(hc->md);
242 if (table) {
243 dm_table_event(table);
244 dm_table_put(table);
245 }
246
247 dm_put(hc->md);
248 if (hc->new_map)
249 dm_table_put(hc->new_map);
250 free_cell(hc);
251 }
252
253 static void dm_hash_remove_all(void)
254 {
255 int i;
256 struct hash_cell *hc;
257 struct list_head *tmp, *n;
258
259 down_write(&_hash_lock);
260 for (i = 0; i < NUM_BUCKETS; i++) {
261 list_for_each_safe (tmp, n, _name_buckets + i) {
262 hc = list_entry(tmp, struct hash_cell, name_list);
263 __hash_remove(hc);
264 }
265 }
266 up_write(&_hash_lock);
267 }
268
269 static int dm_hash_rename(const char *old, const char *new)
270 {
271 char *new_name, *old_name;
272 struct hash_cell *hc;
273
274 /*
275 * duplicate new.
276 */
277 new_name = kstrdup(new, GFP_KERNEL);
278 if (!new_name)
279 return -ENOMEM;
280
281 down_write(&_hash_lock);
282
283 /*
284 * Is new free ?
285 */
286 hc = __get_name_cell(new);
287 if (hc) {
288 DMWARN("asked to rename to an already existing name %s -> %s",
289 old, new);
290 up_write(&_hash_lock);
291 kfree(new_name);
292 return -EBUSY;
293 }
294
295 /*
296 * Is there such a device as 'old' ?
297 */
298 hc = __get_name_cell(old);
299 if (!hc) {
300 DMWARN("asked to rename a non existent device %s -> %s",
301 old, new);
302 up_write(&_hash_lock);
303 kfree(new_name);
304 return -ENXIO;
305 }
306
307 /*
308 * rename and move the name cell.
309 */
310 unregister_with_devfs(hc);
311
312 list_del(&hc->name_list);
313 old_name = hc->name;
314 hc->name = new_name;
315 list_add(&hc->name_list, _name_buckets + hash_str(new_name));
316
317 /* rename the device node in devfs */
318 register_with_devfs(hc);
319
320 up_write(&_hash_lock);
321 kfree(old_name);
322 return 0;
323 }
324
325 /*-----------------------------------------------------------------
326 * Implementation of the ioctl commands
327 *---------------------------------------------------------------*/
328 /*
329 * All the ioctl commands get dispatched to functions with this
330 * prototype.
331 */
332 typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
333
334 static int remove_all(struct dm_ioctl *param, size_t param_size)
335 {
336 dm_hash_remove_all();
337 param->data_size = 0;
338 return 0;
339 }
340
341 /*
342 * Round up the ptr to an 8-byte boundary.
343 */
344 #define ALIGN_MASK 7
345 static inline void *align_ptr(void *ptr)
346 {
347 return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
348 }
349
350 /*
351 * Retrieves the data payload buffer from an already allocated
352 * struct dm_ioctl.
353 */
354 static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
355 size_t *len)
356 {
357 param->data_start = align_ptr(param + 1) - (void *) param;
358
359 if (param->data_start < param_size)
360 *len = param_size - param->data_start;
361 else
362 *len = 0;
363
364 return ((void *) param) + param->data_start;
365 }
366
367 static int list_devices(struct dm_ioctl *param, size_t param_size)
368 {
369 unsigned int i;
370 struct hash_cell *hc;
371 size_t len, needed = 0;
372 struct gendisk *disk;
373 struct dm_name_list *nl, *old_nl = NULL;
374
375 down_write(&_hash_lock);
376
377 /*
378 * Loop through all the devices working out how much
379 * space we need.
380 */
381 for (i = 0; i < NUM_BUCKETS; i++) {
382 list_for_each_entry (hc, _name_buckets + i, name_list) {
383 needed += sizeof(struct dm_name_list);
384 needed += strlen(hc->name) + 1;
385 needed += ALIGN_MASK;
386 }
387 }
388
389 /*
390 * Grab our output buffer.
391 */
392 nl = get_result_buffer(param, param_size, &len);
393 if (len < needed) {
394 param->flags |= DM_BUFFER_FULL_FLAG;
395 goto out;
396 }
397 param->data_size = param->data_start + needed;
398
399 nl->dev = 0; /* Flags no data */
400
401 /*
402 * Now loop through filling out the names.
403 */
404 for (i = 0; i < NUM_BUCKETS; i++) {
405 list_for_each_entry (hc, _name_buckets + i, name_list) {
406 if (old_nl)
407 old_nl->next = (uint32_t) ((void *) nl -
408 (void *) old_nl);
409 disk = dm_disk(hc->md);
410 nl->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
411 nl->next = 0;
412 strcpy(nl->name, hc->name);
413
414 old_nl = nl;
415 nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
416 }
417 }
418
419 out:
420 up_write(&_hash_lock);
421 return 0;
422 }
423
424 static void list_version_get_needed(struct target_type *tt, void *needed_param)
425 {
426 size_t *needed = needed_param;
427
428 *needed += sizeof(struct dm_target_versions);
429 *needed += strlen(tt->name);
430 *needed += ALIGN_MASK;
431 }
432
433 static void list_version_get_info(struct target_type *tt, void *param)
434 {
435 struct vers_iter *info = param;
436
437 /* Check space - it might have changed since the first iteration */
438 if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
439 info->end) {
440
441 info->flags = DM_BUFFER_FULL_FLAG;
442 return;
443 }
444
445 if (info->old_vers)
446 info->old_vers->next = (uint32_t) ((void *)info->vers -
447 (void *)info->old_vers);
448 info->vers->version[0] = tt->version[0];
449 info->vers->version[1] = tt->version[1];
450 info->vers->version[2] = tt->version[2];
451 info->vers->next = 0;
452 strcpy(info->vers->name, tt->name);
453
454 info->old_vers = info->vers;
455 info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
456 }
457
458 static int list_versions(struct dm_ioctl *param, size_t param_size)
459 {
460 size_t len, needed = 0;
461 struct dm_target_versions *vers;
462 struct vers_iter iter_info;
463
464 /*
465 * Loop through all the devices working out how much
466 * space we need.
467 */
468 dm_target_iterate(list_version_get_needed, &needed);
469
470 /*
471 * Grab our output buffer.
472 */
473 vers = get_result_buffer(param, param_size, &len);
474 if (len < needed) {
475 param->flags |= DM_BUFFER_FULL_FLAG;
476 goto out;
477 }
478 param->data_size = param->data_start + needed;
479
480 iter_info.param_size = param_size;
481 iter_info.old_vers = NULL;
482 iter_info.vers = vers;
483 iter_info.flags = 0;
484 iter_info.end = (char *)vers+len;
485
486 /*
487 * Now loop through filling out the names & versions.
488 */
489 dm_target_iterate(list_version_get_info, &iter_info);
490 param->flags |= iter_info.flags;
491
492 out:
493 return 0;
494 }
495
496
497
498 static int check_name(const char *name)
499 {
500 if (strchr(name, '/')) {
501 DMWARN("invalid device name");
502 return -EINVAL;
503 }
504
505 return 0;
506 }
507
508 /*
509 * Fills in a dm_ioctl structure, ready for sending back to
510 * userland.
511 */
512 static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
513 {
514 struct gendisk *disk = dm_disk(md);
515 struct dm_table *table;
516 struct block_device *bdev;
517
518 param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
519 DM_ACTIVE_PRESENT_FLAG);
520
521 if (dm_suspended(md))
522 param->flags |= DM_SUSPEND_FLAG;
523
524 param->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
525
526 if (!(param->flags & DM_SKIP_BDGET_FLAG)) {
527 bdev = bdget_disk(disk, 0);
528 if (!bdev)
529 return -ENXIO;
530
531 /*
532 * Yes, this will be out of date by the time it gets back
533 * to userland, but it is still very useful for
534 * debugging.
535 */
536 param->open_count = bdev->bd_openers;
537 bdput(bdev);
538 } else
539 param->open_count = -1;
540
541 if (disk->policy)
542 param->flags |= DM_READONLY_FLAG;
543
544 param->event_nr = dm_get_event_nr(md);
545
546 table = dm_get_table(md);
547 if (table) {
548 param->flags |= DM_ACTIVE_PRESENT_FLAG;
549 param->target_count = dm_table_get_num_targets(table);
550 dm_table_put(table);
551 } else
552 param->target_count = 0;
553
554 return 0;
555 }
556
557 static int dev_create(struct dm_ioctl *param, size_t param_size)
558 {
559 int r;
560 struct mapped_device *md;
561
562 r = check_name(param->name);
563 if (r)
564 return r;
565
566 if (param->flags & DM_PERSISTENT_DEV_FLAG)
567 r = dm_create_with_minor(MINOR(huge_decode_dev(param->dev)), &md);
568 else
569 r = dm_create(&md);
570
571 if (r)
572 return r;
573
574 r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
575 if (r) {
576 dm_put(md);
577 return r;
578 }
579
580 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
581
582 r = __dev_status(md, param);
583 dm_put(md);
584
585 return r;
586 }
587
588 /*
589 * Always use UUID for lookups if it's present, otherwise use name or dev.
590 */
591 static inline struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
592 {
593 if (*param->uuid)
594 return __get_uuid_cell(param->uuid);
595 else if (*param->name)
596 return __get_name_cell(param->name);
597 else
598 return dm_get_mdptr(huge_decode_dev(param->dev));
599 }
600
601 static inline struct mapped_device *find_device(struct dm_ioctl *param)
602 {
603 struct hash_cell *hc;
604 struct mapped_device *md = NULL;
605
606 down_read(&_hash_lock);
607 hc = __find_device_hash_cell(param);
608 if (hc) {
609 md = hc->md;
610 dm_get(md);
611
612 /*
613 * Sneakily write in both the name and the uuid
614 * while we have the cell.
615 */
616 strncpy(param->name, hc->name, sizeof(param->name));
617 if (hc->uuid)
618 strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
619 else
620 param->uuid[0] = '\0';
621
622 if (hc->new_map)
623 param->flags |= DM_INACTIVE_PRESENT_FLAG;
624 else
625 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
626 }
627 up_read(&_hash_lock);
628
629 return md;
630 }
631
632 static int dev_remove(struct dm_ioctl *param, size_t param_size)
633 {
634 struct hash_cell *hc;
635
636 down_write(&_hash_lock);
637 hc = __find_device_hash_cell(param);
638
639 if (!hc) {
640 DMWARN("device doesn't appear to be in the dev hash table.");
641 up_write(&_hash_lock);
642 return -ENXIO;
643 }
644
645 __hash_remove(hc);
646 up_write(&_hash_lock);
647 param->data_size = 0;
648 return 0;
649 }
650
651 /*
652 * Check a string doesn't overrun the chunk of
653 * memory we copied from userland.
654 */
655 static int invalid_str(char *str, void *end)
656 {
657 while ((void *) str < end)
658 if (!*str++)
659 return 0;
660
661 return -EINVAL;
662 }
663
664 static int dev_rename(struct dm_ioctl *param, size_t param_size)
665 {
666 int r;
667 char *new_name = (char *) param + param->data_start;
668
669 if (new_name < (char *) (param + 1) ||
670 invalid_str(new_name, (void *) param + param_size)) {
671 DMWARN("Invalid new logical volume name supplied.");
672 return -EINVAL;
673 }
674
675 r = check_name(new_name);
676 if (r)
677 return r;
678
679 param->data_size = 0;
680 return dm_hash_rename(param->name, new_name);
681 }
682
683 static int do_suspend(struct dm_ioctl *param)
684 {
685 int r = 0;
686 struct mapped_device *md;
687
688 md = find_device(param);
689 if (!md)
690 return -ENXIO;
691
692 if (!dm_suspended(md))
693 r = dm_suspend(md);
694
695 if (!r)
696 r = __dev_status(md, param);
697
698 dm_put(md);
699 return r;
700 }
701
702 static int do_resume(struct dm_ioctl *param)
703 {
704 int r = 0;
705 struct hash_cell *hc;
706 struct mapped_device *md;
707 struct dm_table *new_map;
708
709 down_write(&_hash_lock);
710
711 hc = __find_device_hash_cell(param);
712 if (!hc) {
713 DMWARN("device doesn't appear to be in the dev hash table.");
714 up_write(&_hash_lock);
715 return -ENXIO;
716 }
717
718 md = hc->md;
719 dm_get(md);
720
721 new_map = hc->new_map;
722 hc->new_map = NULL;
723 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
724
725 up_write(&_hash_lock);
726
727 /* Do we need to load a new map ? */
728 if (new_map) {
729 /* Suspend if it isn't already suspended */
730 if (!dm_suspended(md))
731 dm_suspend(md);
732
733 r = dm_swap_table(md, new_map);
734 if (r) {
735 dm_put(md);
736 dm_table_put(new_map);
737 return r;
738 }
739
740 if (dm_table_get_mode(new_map) & FMODE_WRITE)
741 set_disk_ro(dm_disk(md), 0);
742 else
743 set_disk_ro(dm_disk(md), 1);
744
745 dm_table_put(new_map);
746 }
747
748 if (dm_suspended(md))
749 r = dm_resume(md);
750
751 if (!r)
752 r = __dev_status(md, param);
753
754 dm_put(md);
755 return r;
756 }
757
758 /*
759 * Set or unset the suspension state of a device.
760 * If the device already is in the requested state we just return its status.
761 */
762 static int dev_suspend(struct dm_ioctl *param, size_t param_size)
763 {
764 if (param->flags & DM_SUSPEND_FLAG)
765 return do_suspend(param);
766
767 return do_resume(param);
768 }
769
770 /*
771 * Copies device info back to user space, used by
772 * the create and info ioctls.
773 */
774 static int dev_status(struct dm_ioctl *param, size_t param_size)
775 {
776 int r;
777 struct mapped_device *md;
778
779 md = find_device(param);
780 if (!md)
781 return -ENXIO;
782
783 r = __dev_status(md, param);
784 dm_put(md);
785 return r;
786 }
787
788 /*
789 * Build up the status struct for each target
790 */
791 static void retrieve_status(struct dm_table *table,
792 struct dm_ioctl *param, size_t param_size)
793 {
794 unsigned int i, num_targets;
795 struct dm_target_spec *spec;
796 char *outbuf, *outptr;
797 status_type_t type;
798 size_t remaining, len, used = 0;
799
800 outptr = outbuf = get_result_buffer(param, param_size, &len);
801
802 if (param->flags & DM_STATUS_TABLE_FLAG)
803 type = STATUSTYPE_TABLE;
804 else
805 type = STATUSTYPE_INFO;
806
807 /* Get all the target info */
808 num_targets = dm_table_get_num_targets(table);
809 for (i = 0; i < num_targets; i++) {
810 struct dm_target *ti = dm_table_get_target(table, i);
811
812 remaining = len - (outptr - outbuf);
813 if (remaining <= sizeof(struct dm_target_spec)) {
814 param->flags |= DM_BUFFER_FULL_FLAG;
815 break;
816 }
817
818 spec = (struct dm_target_spec *) outptr;
819
820 spec->status = 0;
821 spec->sector_start = ti->begin;
822 spec->length = ti->len;
823 strncpy(spec->target_type, ti->type->name,
824 sizeof(spec->target_type));
825
826 outptr += sizeof(struct dm_target_spec);
827 remaining = len - (outptr - outbuf);
828 if (remaining <= 0) {
829 param->flags |= DM_BUFFER_FULL_FLAG;
830 break;
831 }
832
833 /* Get the status/table string from the target driver */
834 if (ti->type->status) {
835 if (ti->type->status(ti, type, outptr, remaining)) {
836 param->flags |= DM_BUFFER_FULL_FLAG;
837 break;
838 }
839 } else
840 outptr[0] = '\0';
841
842 outptr += strlen(outptr) + 1;
843 used = param->data_start + (outptr - outbuf);
844
845 outptr = align_ptr(outptr);
846 spec->next = outptr - outbuf;
847 }
848
849 if (used)
850 param->data_size = used;
851
852 param->target_count = num_targets;
853 }
854
855 /*
856 * Wait for a device to report an event
857 */
858 static int dev_wait(struct dm_ioctl *param, size_t param_size)
859 {
860 int r;
861 struct mapped_device *md;
862 struct dm_table *table;
863
864 md = find_device(param);
865 if (!md)
866 return -ENXIO;
867
868 /*
869 * Wait for a notification event
870 */
871 if (dm_wait_event(md, param->event_nr)) {
872 r = -ERESTARTSYS;
873 goto out;
874 }
875
876 /*
877 * The userland program is going to want to know what
878 * changed to trigger the event, so we may as well tell
879 * him and save an ioctl.
880 */
881 r = __dev_status(md, param);
882 if (r)
883 goto out;
884
885 table = dm_get_table(md);
886 if (table) {
887 retrieve_status(table, param, param_size);
888 dm_table_put(table);
889 }
890
891 out:
892 dm_put(md);
893 return r;
894 }
895
896 static inline int get_mode(struct dm_ioctl *param)
897 {
898 int mode = FMODE_READ | FMODE_WRITE;
899
900 if (param->flags & DM_READONLY_FLAG)
901 mode = FMODE_READ;
902
903 return mode;
904 }
905
906 static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
907 struct dm_target_spec **spec, char **target_params)
908 {
909 *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
910 *target_params = (char *) (*spec + 1);
911
912 if (*spec < (last + 1))
913 return -EINVAL;
914
915 return invalid_str(*target_params, end);
916 }
917
918 static int populate_table(struct dm_table *table,
919 struct dm_ioctl *param, size_t param_size)
920 {
921 int r;
922 unsigned int i = 0;
923 struct dm_target_spec *spec = (struct dm_target_spec *) param;
924 uint32_t next = param->data_start;
925 void *end = (void *) param + param_size;
926 char *target_params;
927
928 if (!param->target_count) {
929 DMWARN("populate_table: no targets specified");
930 return -EINVAL;
931 }
932
933 for (i = 0; i < param->target_count; i++) {
934
935 r = next_target(spec, next, end, &spec, &target_params);
936 if (r) {
937 DMWARN("unable to find target");
938 return r;
939 }
940
941 r = dm_table_add_target(table, spec->target_type,
942 (sector_t) spec->sector_start,
943 (sector_t) spec->length,
944 target_params);
945 if (r) {
946 DMWARN("error adding target to table");
947 return r;
948 }
949
950 next = spec->next;
951 }
952
953 return dm_table_complete(table);
954 }
955
956 static int table_load(struct dm_ioctl *param, size_t param_size)
957 {
958 int r;
959 struct hash_cell *hc;
960 struct dm_table *t;
961
962 r = dm_table_create(&t, get_mode(param), param->target_count);
963 if (r)
964 return r;
965
966 r = populate_table(t, param, param_size);
967 if (r) {
968 dm_table_put(t);
969 return r;
970 }
971
972 down_write(&_hash_lock);
973 hc = __find_device_hash_cell(param);
974 if (!hc) {
975 DMWARN("device doesn't appear to be in the dev hash table.");
976 up_write(&_hash_lock);
977 dm_table_put(t);
978 return -ENXIO;
979 }
980
981 if (hc->new_map)
982 dm_table_put(hc->new_map);
983 hc->new_map = t;
984 param->flags |= DM_INACTIVE_PRESENT_FLAG;
985
986 r = __dev_status(hc->md, param);
987 up_write(&_hash_lock);
988 return r;
989 }
990
991 static int table_clear(struct dm_ioctl *param, size_t param_size)
992 {
993 int r;
994 struct hash_cell *hc;
995
996 down_write(&_hash_lock);
997
998 hc = __find_device_hash_cell(param);
999 if (!hc) {
1000 DMWARN("device doesn't appear to be in the dev hash table.");
1001 up_write(&_hash_lock);
1002 return -ENXIO;
1003 }
1004
1005 if (hc->new_map) {
1006 dm_table_put(hc->new_map);
1007 hc->new_map = NULL;
1008 }
1009
1010 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
1011
1012 r = __dev_status(hc->md, param);
1013 up_write(&_hash_lock);
1014 return r;
1015 }
1016
1017 /*
1018 * Retrieves a list of devices used by a particular dm device.
1019 */
1020 static void retrieve_deps(struct dm_table *table,
1021 struct dm_ioctl *param, size_t param_size)
1022 {
1023 unsigned int count = 0;
1024 struct list_head *tmp;
1025 size_t len, needed;
1026 struct dm_dev *dd;
1027 struct dm_target_deps *deps;
1028
1029 deps = get_result_buffer(param, param_size, &len);
1030
1031 /*
1032 * Count the devices.
1033 */
1034 list_for_each (tmp, dm_table_get_devices(table))
1035 count++;
1036
1037 /*
1038 * Check we have enough space.
1039 */
1040 needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
1041 if (len < needed) {
1042 param->flags |= DM_BUFFER_FULL_FLAG;
1043 return;
1044 }
1045
1046 /*
1047 * Fill in the devices.
1048 */
1049 deps->count = count;
1050 count = 0;
1051 list_for_each_entry (dd, dm_table_get_devices(table), list)
1052 deps->dev[count++] = huge_encode_dev(dd->bdev->bd_dev);
1053
1054 param->data_size = param->data_start + needed;
1055 }
1056
1057 static int table_deps(struct dm_ioctl *param, size_t param_size)
1058 {
1059 int r = 0;
1060 struct mapped_device *md;
1061 struct dm_table *table;
1062
1063 md = find_device(param);
1064 if (!md)
1065 return -ENXIO;
1066
1067 r = __dev_status(md, param);
1068 if (r)
1069 goto out;
1070
1071 table = dm_get_table(md);
1072 if (table) {
1073 retrieve_deps(table, param, param_size);
1074 dm_table_put(table);
1075 }
1076
1077 out:
1078 dm_put(md);
1079 return r;
1080 }
1081
1082 /*
1083 * Return the status of a device as a text string for each
1084 * target.
1085 */
1086 static int table_status(struct dm_ioctl *param, size_t param_size)
1087 {
1088 int r;
1089 struct mapped_device *md;
1090 struct dm_table *table;
1091
1092 md = find_device(param);
1093 if (!md)
1094 return -ENXIO;
1095
1096 r = __dev_status(md, param);
1097 if (r)
1098 goto out;
1099
1100 table = dm_get_table(md);
1101 if (table) {
1102 retrieve_status(table, param, param_size);
1103 dm_table_put(table);
1104 }
1105
1106 out:
1107 dm_put(md);
1108 return r;
1109 }
1110
1111 /*
1112 * Pass a message to the target that's at the supplied device offset.
1113 */
1114 static int target_message(struct dm_ioctl *param, size_t param_size)
1115 {
1116 int r, argc;
1117 char **argv;
1118 struct mapped_device *md;
1119 struct dm_table *table;
1120 struct dm_target *ti;
1121 struct dm_target_msg *tmsg = (void *) param + param->data_start;
1122
1123 md = find_device(param);
1124 if (!md)
1125 return -ENXIO;
1126
1127 r = __dev_status(md, param);
1128 if (r)
1129 goto out;
1130
1131 if (tmsg < (struct dm_target_msg *) (param + 1) ||
1132 invalid_str(tmsg->message, (void *) param + param_size)) {
1133 DMWARN("Invalid target message parameters.");
1134 r = -EINVAL;
1135 goto out;
1136 }
1137
1138 r = dm_split_args(&argc, &argv, tmsg->message);
1139 if (r) {
1140 DMWARN("Failed to split target message parameters");
1141 goto out;
1142 }
1143
1144 table = dm_get_table(md);
1145 if (!table)
1146 goto out_argv;
1147
1148 if (tmsg->sector >= dm_table_get_size(table)) {
1149 DMWARN("Target message sector outside device.");
1150 r = -EINVAL;
1151 goto out_table;
1152 }
1153
1154 ti = dm_table_find_target(table, tmsg->sector);
1155 if (ti->type->message)
1156 r = ti->type->message(ti, argc, argv);
1157 else {
1158 DMWARN("Target type does not support messages");
1159 r = -EINVAL;
1160 }
1161
1162 out_table:
1163 dm_table_put(table);
1164 out_argv:
1165 kfree(argv);
1166 out:
1167 param->data_size = 0;
1168 dm_put(md);
1169 return r;
1170 }
1171
1172 /*-----------------------------------------------------------------
1173 * Implementation of open/close/ioctl on the special char
1174 * device.
1175 *---------------------------------------------------------------*/
1176 static ioctl_fn lookup_ioctl(unsigned int cmd)
1177 {
1178 static struct {
1179 int cmd;
1180 ioctl_fn fn;
1181 } _ioctls[] = {
1182 {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
1183 {DM_REMOVE_ALL_CMD, remove_all},
1184 {DM_LIST_DEVICES_CMD, list_devices},
1185
1186 {DM_DEV_CREATE_CMD, dev_create},
1187 {DM_DEV_REMOVE_CMD, dev_remove},
1188 {DM_DEV_RENAME_CMD, dev_rename},
1189 {DM_DEV_SUSPEND_CMD, dev_suspend},
1190 {DM_DEV_STATUS_CMD, dev_status},
1191 {DM_DEV_WAIT_CMD, dev_wait},
1192
1193 {DM_TABLE_LOAD_CMD, table_load},
1194 {DM_TABLE_CLEAR_CMD, table_clear},
1195 {DM_TABLE_DEPS_CMD, table_deps},
1196 {DM_TABLE_STATUS_CMD, table_status},
1197
1198 {DM_LIST_VERSIONS_CMD, list_versions},
1199
1200 {DM_TARGET_MSG_CMD, target_message}
1201 };
1202
1203 return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
1204 }
1205
1206 /*
1207 * As well as checking the version compatibility this always
1208 * copies the kernel interface version out.
1209 */
1210 static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
1211 {
1212 uint32_t version[3];
1213 int r = 0;
1214
1215 if (copy_from_user(version, user->version, sizeof(version)))
1216 return -EFAULT;
1217
1218 if ((DM_VERSION_MAJOR != version[0]) ||
1219 (DM_VERSION_MINOR < version[1])) {
1220 DMWARN("ioctl interface mismatch: "
1221 "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
1222 DM_VERSION_MAJOR, DM_VERSION_MINOR,
1223 DM_VERSION_PATCHLEVEL,
1224 version[0], version[1], version[2], cmd);
1225 r = -EINVAL;
1226 }
1227
1228 /*
1229 * Fill in the kernel version.
1230 */
1231 version[0] = DM_VERSION_MAJOR;
1232 version[1] = DM_VERSION_MINOR;
1233 version[2] = DM_VERSION_PATCHLEVEL;
1234 if (copy_to_user(user->version, version, sizeof(version)))
1235 return -EFAULT;
1236
1237 return r;
1238 }
1239
1240 static void free_params(struct dm_ioctl *param)
1241 {
1242 vfree(param);
1243 }
1244
1245 static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
1246 {
1247 struct dm_ioctl tmp, *dmi;
1248
1249 if (copy_from_user(&tmp, user, sizeof(tmp)))
1250 return -EFAULT;
1251
1252 if (tmp.data_size < sizeof(tmp))
1253 return -EINVAL;
1254
1255 dmi = (struct dm_ioctl *) vmalloc(tmp.data_size);
1256 if (!dmi)
1257 return -ENOMEM;
1258
1259 if (copy_from_user(dmi, user, tmp.data_size)) {
1260 vfree(dmi);
1261 return -EFAULT;
1262 }
1263
1264 *param = dmi;
1265 return 0;
1266 }
1267
1268 static int validate_params(uint cmd, struct dm_ioctl *param)
1269 {
1270 /* Always clear this flag */
1271 param->flags &= ~DM_BUFFER_FULL_FLAG;
1272
1273 /* Ignores parameters */
1274 if (cmd == DM_REMOVE_ALL_CMD ||
1275 cmd == DM_LIST_DEVICES_CMD ||
1276 cmd == DM_LIST_VERSIONS_CMD)
1277 return 0;
1278
1279 if ((cmd == DM_DEV_CREATE_CMD)) {
1280 if (!*param->name) {
1281 DMWARN("name not supplied when creating device");
1282 return -EINVAL;
1283 }
1284 } else if ((*param->uuid && *param->name)) {
1285 DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
1286 return -EINVAL;
1287 }
1288
1289 /* Ensure strings are terminated */
1290 param->name[DM_NAME_LEN - 1] = '\0';
1291 param->uuid[DM_UUID_LEN - 1] = '\0';
1292
1293 return 0;
1294 }
1295
1296 static int ctl_ioctl(struct inode *inode, struct file *file,
1297 uint command, ulong u)
1298 {
1299 int r = 0;
1300 unsigned int cmd;
1301 struct dm_ioctl *param;
1302 struct dm_ioctl __user *user = (struct dm_ioctl __user *) u;
1303 ioctl_fn fn = NULL;
1304 size_t param_size;
1305
1306 /* only root can play with this */
1307 if (!capable(CAP_SYS_ADMIN))
1308 return -EACCES;
1309
1310 if (_IOC_TYPE(command) != DM_IOCTL)
1311 return -ENOTTY;
1312
1313 cmd = _IOC_NR(command);
1314
1315 /*
1316 * Check the interface version passed in. This also
1317 * writes out the kernel's interface version.
1318 */
1319 r = check_version(cmd, user);
1320 if (r)
1321 return r;
1322
1323 /*
1324 * Nothing more to do for the version command.
1325 */
1326 if (cmd == DM_VERSION_CMD)
1327 return 0;
1328
1329 fn = lookup_ioctl(cmd);
1330 if (!fn) {
1331 DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
1332 return -ENOTTY;
1333 }
1334
1335 /*
1336 * Trying to avoid low memory issues when a device is
1337 * suspended.
1338 */
1339 current->flags |= PF_MEMALLOC;
1340
1341 /*
1342 * Copy the parameters into kernel space.
1343 */
1344 r = copy_params(user, &param);
1345 if (r) {
1346 current->flags &= ~PF_MEMALLOC;
1347 return r;
1348 }
1349
1350 /*
1351 * FIXME: eventually we will remove the PF_MEMALLOC flag
1352 * here. However the tools still do nasty things like
1353 * 'load' while a device is suspended.
1354 */
1355
1356 r = validate_params(cmd, param);
1357 if (r)
1358 goto out;
1359
1360 param_size = param->data_size;
1361 param->data_size = sizeof(*param);
1362 r = fn(param, param_size);
1363
1364 /*
1365 * Copy the results back to userland.
1366 */
1367 if (!r && copy_to_user(user, param, param->data_size))
1368 r = -EFAULT;
1369
1370 out:
1371 free_params(param);
1372 current->flags &= ~PF_MEMALLOC;
1373 return r;
1374 }
1375
1376 static struct file_operations _ctl_fops = {
1377 .ioctl = ctl_ioctl,
1378 .owner = THIS_MODULE,
1379 };
1380
1381 static struct miscdevice _dm_misc = {
1382 .minor = MISC_DYNAMIC_MINOR,
1383 .name = DM_NAME,
1384 .devfs_name = "mapper/control",
1385 .fops = &_ctl_fops
1386 };
1387
1388 /*
1389 * Create misc character device and link to DM_DIR/control.
1390 */
1391 int __init dm_interface_init(void)
1392 {
1393 int r;
1394
1395 r = dm_hash_init();
1396 if (r)
1397 return r;
1398
1399 r = misc_register(&_dm_misc);
1400 if (r) {
1401 DMERR("misc_register failed for control device");
1402 dm_hash_exit();
1403 return r;
1404 }
1405
1406 DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
1407 DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
1408 DM_DRIVER_EMAIL);
1409 return 0;
1410 }
1411
1412 void dm_interface_exit(void)
1413 {
1414 if (misc_deregister(&_dm_misc) < 0)
1415 DMERR("misc_deregister failed for control device");
1416
1417 dm_hash_exit();
1418 }
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