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RT-AC56 3.0.0.4.374.37 core
[tomato.git] / release / src-rt-6.x.4708 / linux / linux-2.6.36 / drivers / md / dm-ioctl.c
blob3e39193e5036e709665e08345ba242d83662c606
1 /*
2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
3 * Copyright (C) 2004 - 2006 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/dm-ioctl.h>
17 #include <linux/hdreg.h>
18 #include <linux/compat.h>
19
20 #include <asm/uaccess.h>
21
22 #define DM_MSG_PREFIX "ioctl"
23 #define DM_DRIVER_EMAIL "dm-devel@redhat.com"
24
25 /*-----------------------------------------------------------------
26 * The ioctl interface needs to be able to look up devices by
27 * name or uuid.
28 *---------------------------------------------------------------*/
29 struct hash_cell {
30 struct list_head name_list;
31 struct list_head uuid_list;
32
33 char *name;
34 char *uuid;
35 struct mapped_device *md;
36 struct dm_table *new_map;
37 };
38
39 struct vers_iter {
40 size_t param_size;
41 struct dm_target_versions *vers, *old_vers;
42 char *end;
43 uint32_t flags;
44 };
45
46
47 #define NUM_BUCKETS 64
48 #define MASK_BUCKETS (NUM_BUCKETS - 1)
49 static struct list_head _name_buckets[NUM_BUCKETS];
50 static struct list_head _uuid_buckets[NUM_BUCKETS];
51
52 static void dm_hash_remove_all(int keep_open_devices);
53
54 /*
55 * Guards access to both hash tables.
56 */
57 static DECLARE_RWSEM(_hash_lock);
58
59 /*
60 * Protects use of mdptr to obtain hash cell name and uuid from mapped device.
61 */
62 static DEFINE_MUTEX(dm_hash_cells_mutex);
63
64 static void init_buckets(struct list_head *buckets)
65 {
66 unsigned int i;
67
68 for (i = 0; i < NUM_BUCKETS; i++)
69 INIT_LIST_HEAD(buckets + i);
70 }
71
72 static int dm_hash_init(void)
73 {
74 init_buckets(_name_buckets);
75 init_buckets(_uuid_buckets);
76 return 0;
77 }
78
79 static void dm_hash_exit(void)
80 {
81 dm_hash_remove_all(0);
82 }
83
84 /*-----------------------------------------------------------------
85 * Hash function:
86 * We're not really concerned with the str hash function being
87 * fast since it's only used by the ioctl interface.
88 *---------------------------------------------------------------*/
89 static unsigned int hash_str(const char *str)
90 {
91 const unsigned int hash_mult = 2654435387U;
92 unsigned int h = 0;
93
94 while (*str)
95 h = (h + (unsigned int) *str++) * hash_mult;
96
97 return h & MASK_BUCKETS;
98 }
99
100 /*-----------------------------------------------------------------
101 * Code for looking up a device by name
102 *---------------------------------------------------------------*/
103 static struct hash_cell *__get_name_cell(const char *str)
104 {
105 struct hash_cell *hc;
106 unsigned int h = hash_str(str);
107
108 list_for_each_entry (hc, _name_buckets + h, name_list)
109 if (!strcmp(hc->name, str)) {
110 dm_get(hc->md);
111 return hc;
112 }
113
114 return NULL;
115 }
116
117 static struct hash_cell *__get_uuid_cell(const char *str)
118 {
119 struct hash_cell *hc;
120 unsigned int h = hash_str(str);
121
122 list_for_each_entry (hc, _uuid_buckets + h, uuid_list)
123 if (!strcmp(hc->uuid, str)) {
124 dm_get(hc->md);
125 return hc;
126 }
127
128 return NULL;
129 }
130
131 /*-----------------------------------------------------------------
132 * Inserting, removing and renaming a device.
133 *---------------------------------------------------------------*/
134 static struct hash_cell *alloc_cell(const char *name, const char *uuid,
135 struct mapped_device *md)
136 {
137 struct hash_cell *hc;
138
139 hc = kmalloc(sizeof(*hc), GFP_KERNEL);
140 if (!hc)
141 return NULL;
142
143 hc->name = kstrdup(name, GFP_KERNEL);
144 if (!hc->name) {
145 kfree(hc);
146 return NULL;
147 }
148
149 if (!uuid)
150 hc->uuid = NULL;
151
152 else {
153 hc->uuid = kstrdup(uuid, GFP_KERNEL);
154 if (!hc->uuid) {
155 kfree(hc->name);
156 kfree(hc);
157 return NULL;
158 }
159 }
160
161 INIT_LIST_HEAD(&hc->name_list);
162 INIT_LIST_HEAD(&hc->uuid_list);
163 hc->md = md;
164 hc->new_map = NULL;
165 return hc;
166 }
167
168 static void free_cell(struct hash_cell *hc)
169 {
170 if (hc) {
171 kfree(hc->name);
172 kfree(hc->uuid);
173 kfree(hc);
174 }
175 }
176
177 /*
178 * The kdev_t and uuid of a device can never change once it is
179 * initially inserted.
180 */
181 static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md)
182 {
183 struct hash_cell *cell, *hc;
184
185 /*
186 * Allocate the new cells.
187 */
188 cell = alloc_cell(name, uuid, md);
189 if (!cell)
190 return -ENOMEM;
191
192 /*
193 * Insert the cell into both hash tables.
194 */
195 down_write(&_hash_lock);
196 hc = __get_name_cell(name);
197 if (hc) {
198 dm_put(hc->md);
199 goto bad;
200 }
201
202 list_add(&cell->name_list, _name_buckets + hash_str(name));
203
204 if (uuid) {
205 hc = __get_uuid_cell(uuid);
206 if (hc) {
207 list_del(&cell->name_list);
208 dm_put(hc->md);
209 goto bad;
210 }
211 list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
212 }
213 dm_get(md);
214 mutex_lock(&dm_hash_cells_mutex);
215 dm_set_mdptr(md, cell);
216 mutex_unlock(&dm_hash_cells_mutex);
217 up_write(&_hash_lock);
218
219 return 0;
220
221 bad:
222 up_write(&_hash_lock);
223 free_cell(cell);
224 return -EBUSY;
225 }
226
227 static void __hash_remove(struct hash_cell *hc)
228 {
229 struct dm_table *table;
230
231 /* remove from the dev hash */
232 list_del(&hc->uuid_list);
233 list_del(&hc->name_list);
234 mutex_lock(&dm_hash_cells_mutex);
235 dm_set_mdptr(hc->md, NULL);
236 mutex_unlock(&dm_hash_cells_mutex);
237
238 table = dm_get_live_table(hc->md);
239 if (table) {
240 dm_table_event(table);
241 dm_table_put(table);
242 }
243
244 if (hc->new_map)
245 dm_table_destroy(hc->new_map);
246 dm_put(hc->md);
247 free_cell(hc);
248 }
249
250 static void dm_hash_remove_all(int keep_open_devices)
251 {
252 int i, dev_skipped;
253 struct hash_cell *hc;
254 struct mapped_device *md;
255
256 retry:
257 dev_skipped = 0;
258
259 down_write(&_hash_lock);
260
261 for (i = 0; i < NUM_BUCKETS; i++) {
262 list_for_each_entry(hc, _name_buckets + i, name_list) {
263 md = hc->md;
264 dm_get(md);
265
266 if (keep_open_devices && dm_lock_for_deletion(md)) {
267 dm_put(md);
268 dev_skipped++;
269 continue;
270 }
271
272 __hash_remove(hc);
273
274 up_write(&_hash_lock);
275
276 dm_put(md);
277 if (likely(keep_open_devices))
278 dm_destroy(md);
279 else
280 dm_destroy_immediate(md);
281
282 /*
283 * Some mapped devices may be using other mapped
284 * devices, so repeat until we make no further
285 * progress. If a new mapped device is created
286 * here it will also get removed.
287 */
288 goto retry;
289 }
290 }
291
292 up_write(&_hash_lock);
293
294 if (dev_skipped)
295 DMWARN("remove_all left %d open device(s)", dev_skipped);
296 }
297
298 static struct mapped_device *dm_hash_rename(struct dm_ioctl *param,
299 const char *new)
300 {
301 char *new_name, *old_name;
302 struct hash_cell *hc;
303 struct dm_table *table;
304 struct mapped_device *md;
305
306 /*
307 * duplicate new.
308 */
309 new_name = kstrdup(new, GFP_KERNEL);
310 if (!new_name)
311 return ERR_PTR(-ENOMEM);
312
313 down_write(&_hash_lock);
314
315 /*
316 * Is new free ?
317 */
318 hc = __get_name_cell(new);
319 if (hc) {
320 DMWARN("asked to rename to an already-existing name %s -> %s",
321 param->name, new);
322 dm_put(hc->md);
323 up_write(&_hash_lock);
324 kfree(new_name);
325 return ERR_PTR(-EBUSY);
326 }
327
328 /*
329 * Is there such a device as 'old' ?
330 */
331 hc = __get_name_cell(param->name);
332 if (!hc) {
333 DMWARN("asked to rename a non-existent device %s -> %s",
334 param->name, new);
335 up_write(&_hash_lock);
336 kfree(new_name);
337 return ERR_PTR(-ENXIO);
338 }
339
340 /*
341 * rename and move the name cell.
342 */
343 list_del(&hc->name_list);
344 old_name = hc->name;
345 mutex_lock(&dm_hash_cells_mutex);
346 hc->name = new_name;
347 mutex_unlock(&dm_hash_cells_mutex);
348 list_add(&hc->name_list, _name_buckets + hash_str(new_name));
349
350 /*
351 * Wake up any dm event waiters.
352 */
353 table = dm_get_live_table(hc->md);
354 if (table) {
355 dm_table_event(table);
356 dm_table_put(table);
357 }
358
359 if (!dm_kobject_uevent(hc->md, KOBJ_CHANGE, param->event_nr))
360 param->flags |= DM_UEVENT_GENERATED_FLAG;
361
362 md = hc->md;
363 up_write(&_hash_lock);
364 kfree(old_name);
365
366 return md;
367 }
368
369 /*-----------------------------------------------------------------
370 * Implementation of the ioctl commands
371 *---------------------------------------------------------------*/
372 /*
373 * All the ioctl commands get dispatched to functions with this
374 * prototype.
375 */
376 typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
377
378 static int remove_all(struct dm_ioctl *param, size_t param_size)
379 {
380 dm_hash_remove_all(1);
381 param->data_size = 0;
382 return 0;
383 }
384
385 /*
386 * Round up the ptr to an 8-byte boundary.
387 */
388 #define ALIGN_MASK 7
389 static inline void *align_ptr(void *ptr)
390 {
391 return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
392 }
393
394 /*
395 * Retrieves the data payload buffer from an already allocated
396 * struct dm_ioctl.
397 */
398 static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
399 size_t *len)
400 {
401 param->data_start = align_ptr(param + 1) - (void *) param;
402
403 if (param->data_start < param_size)
404 *len = param_size - param->data_start;
405 else
406 *len = 0;
407
408 return ((void *) param) + param->data_start;
409 }
410
411 static int list_devices(struct dm_ioctl *param, size_t param_size)
412 {
413 unsigned int i;
414 struct hash_cell *hc;
415 size_t len, needed = 0;
416 struct gendisk *disk;
417 struct dm_name_list *nl, *old_nl = NULL;
418
419 down_write(&_hash_lock);
420
421 /*
422 * Loop through all the devices working out how much
423 * space we need.
424 */
425 for (i = 0; i < NUM_BUCKETS; i++) {
426 list_for_each_entry (hc, _name_buckets + i, name_list) {
427 needed += sizeof(struct dm_name_list);
428 needed += strlen(hc->name) + 1;
429 needed += ALIGN_MASK;
430 }
431 }
432
433 /*
434 * Grab our output buffer.
435 */
436 nl = get_result_buffer(param, param_size, &len);
437 if (len < needed) {
438 param->flags |= DM_BUFFER_FULL_FLAG;
439 goto out;
440 }
441 param->data_size = param->data_start + needed;
442
443 nl->dev = 0; /* Flags no data */
444
445 /*
446 * Now loop through filling out the names.
447 */
448 for (i = 0; i < NUM_BUCKETS; i++) {
449 list_for_each_entry (hc, _name_buckets + i, name_list) {
450 if (old_nl)
451 old_nl->next = (uint32_t) ((void *) nl -
452 (void *) old_nl);
453 disk = dm_disk(hc->md);
454 nl->dev = huge_encode_dev(disk_devt(disk));
455 nl->next = 0;
456 strcpy(nl->name, hc->name);
457
458 old_nl = nl;
459 nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
460 }
461 }
462
463 out:
464 up_write(&_hash_lock);
465 return 0;
466 }
467
468 static void list_version_get_needed(struct target_type *tt, void *needed_param)
469 {
470 size_t *needed = needed_param;
471
472 *needed += sizeof(struct dm_target_versions);
473 *needed += strlen(tt->name);
474 *needed += ALIGN_MASK;
475 }
476
477 static void list_version_get_info(struct target_type *tt, void *param)
478 {
479 struct vers_iter *info = param;
480
481 /* Check space - it might have changed since the first iteration */
482 if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
483 info->end) {
484
485 info->flags = DM_BUFFER_FULL_FLAG;
486 return;
487 }
488
489 if (info->old_vers)
490 info->old_vers->next = (uint32_t) ((void *)info->vers -
491 (void *)info->old_vers);
492 info->vers->version[0] = tt->version[0];
493 info->vers->version[1] = tt->version[1];
494 info->vers->version[2] = tt->version[2];
495 info->vers->next = 0;
496 strcpy(info->vers->name, tt->name);
497
498 info->old_vers = info->vers;
499 info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
500 }
501
502 static int list_versions(struct dm_ioctl *param, size_t param_size)
503 {
504 size_t len, needed = 0;
505 struct dm_target_versions *vers;
506 struct vers_iter iter_info;
507
508 /*
509 * Loop through all the devices working out how much
510 * space we need.
511 */
512 dm_target_iterate(list_version_get_needed, &needed);
513
514 /*
515 * Grab our output buffer.
516 */
517 vers = get_result_buffer(param, param_size, &len);
518 if (len < needed) {
519 param->flags |= DM_BUFFER_FULL_FLAG;
520 goto out;
521 }
522 param->data_size = param->data_start + needed;
523
524 iter_info.param_size = param_size;
525 iter_info.old_vers = NULL;
526 iter_info.vers = vers;
527 iter_info.flags = 0;
528 iter_info.end = (char *)vers+len;
529
530 /*
531 * Now loop through filling out the names & versions.
532 */
533 dm_target_iterate(list_version_get_info, &iter_info);
534 param->flags |= iter_info.flags;
535
536 out:
537 return 0;
538 }
539
540 static int check_name(const char *name)
541 {
542 if (strchr(name, '/')) {
543 DMWARN("invalid device name");
544 return -EINVAL;
545 }
546
547 return 0;
548 }
549
550 /*
551 * On successful return, the caller must not attempt to acquire
552 * _hash_lock without first calling dm_table_put, because dm_table_destroy
553 * waits for this dm_table_put and could be called under this lock.
554 */
555 static struct dm_table *dm_get_inactive_table(struct mapped_device *md)
556 {
557 struct hash_cell *hc;
558 struct dm_table *table = NULL;
559
560 down_read(&_hash_lock);
561 hc = dm_get_mdptr(md);
562 if (!hc || hc->md != md) {
563 DMWARN("device has been removed from the dev hash table.");
564 goto out;
565 }
566
567 table = hc->new_map;
568 if (table)
569 dm_table_get(table);
570
571 out:
572 up_read(&_hash_lock);
573
574 return table;
575 }
576
577 static struct dm_table *dm_get_live_or_inactive_table(struct mapped_device *md,
578 struct dm_ioctl *param)
579 {
580 return (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) ?
581 dm_get_inactive_table(md) : dm_get_live_table(md);
582 }
583
584 /*
585 * Fills in a dm_ioctl structure, ready for sending back to
586 * userland.
587 */
588 static void __dev_status(struct mapped_device *md, struct dm_ioctl *param)
589 {
590 struct gendisk *disk = dm_disk(md);
591 struct dm_table *table;
592
593 param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
594 DM_ACTIVE_PRESENT_FLAG);
595
596 if (dm_suspended_md(md))
597 param->flags |= DM_SUSPEND_FLAG;
598
599 param->dev = huge_encode_dev(disk_devt(disk));
600
601 /*
602 * Yes, this will be out of date by the time it gets back
603 * to userland, but it is still very useful for
604 * debugging.
605 */
606 param->open_count = dm_open_count(md);
607
608 param->event_nr = dm_get_event_nr(md);
609 param->target_count = 0;
610
611 table = dm_get_live_table(md);
612 if (table) {
613 if (!(param->flags & DM_QUERY_INACTIVE_TABLE_FLAG)) {
614 if (get_disk_ro(disk))
615 param->flags |= DM_READONLY_FLAG;
616 param->target_count = dm_table_get_num_targets(table);
617 }
618 dm_table_put(table);
619
620 param->flags |= DM_ACTIVE_PRESENT_FLAG;
621 }
622
623 if (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) {
624 table = dm_get_inactive_table(md);
625 if (table) {
626 if (!(dm_table_get_mode(table) & FMODE_WRITE))
627 param->flags |= DM_READONLY_FLAG;
628 param->target_count = dm_table_get_num_targets(table);
629 dm_table_put(table);
630 }
631 }
632 }
633
634 static int dev_create(struct dm_ioctl *param, size_t param_size)
635 {
636 int r, m = DM_ANY_MINOR;
637 struct mapped_device *md;
638
639 r = check_name(param->name);
640 if (r)
641 return r;
642
643 if (param->flags & DM_PERSISTENT_DEV_FLAG)
644 m = MINOR(huge_decode_dev(param->dev));
645
646 r = dm_create(m, &md);
647 if (r)
648 return r;
649
650 r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
651 if (r) {
652 dm_put(md);
653 dm_destroy(md);
654 return r;
655 }
656
657 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
658
659 __dev_status(md, param);
660
661 dm_put(md);
662
663 return 0;
664 }
665
666 /*
667 * Always use UUID for lookups if it's present, otherwise use name or dev.
668 */
669 static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
670 {
671 struct mapped_device *md;
672 void *mdptr = NULL;
673
674 if (*param->uuid)
675 return __get_uuid_cell(param->uuid);
676
677 if (*param->name)
678 return __get_name_cell(param->name);
679
680 md = dm_get_md(huge_decode_dev(param->dev));
681 if (!md)
682 goto out;
683
684 mdptr = dm_get_mdptr(md);
685 if (!mdptr)
686 dm_put(md);
687
688 out:
689 return mdptr;
690 }
691
692 static struct mapped_device *find_device(struct dm_ioctl *param)
693 {
694 struct hash_cell *hc;
695 struct mapped_device *md = NULL;
696
697 down_read(&_hash_lock);
698 hc = __find_device_hash_cell(param);
699 if (hc) {
700 md = hc->md;
701
702 /*
703 * Sneakily write in both the name and the uuid
704 * while we have the cell.
705 */
706 strlcpy(param->name, hc->name, sizeof(param->name));
707 if (hc->uuid)
708 strlcpy(param->uuid, hc->uuid, sizeof(param->uuid));
709 else
710 param->uuid[0] = '\0';
711
712 if (hc->new_map)
713 param->flags |= DM_INACTIVE_PRESENT_FLAG;
714 else
715 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
716 }
717 up_read(&_hash_lock);
718
719 return md;
720 }
721
722 static int dev_remove(struct dm_ioctl *param, size_t param_size)
723 {
724 struct hash_cell *hc;
725 struct mapped_device *md;
726 int r;
727
728 down_write(&_hash_lock);
729 hc = __find_device_hash_cell(param);
730
731 if (!hc) {
732 DMWARN("device doesn't appear to be in the dev hash table.");
733 up_write(&_hash_lock);
734 return -ENXIO;
735 }
736
737 md = hc->md;
738
739 /*
740 * Ensure the device is not open and nothing further can open it.
741 */
742 r = dm_lock_for_deletion(md);
743 if (r) {
744 DMWARN("unable to remove open device %s", hc->name);
745 up_write(&_hash_lock);
746 dm_put(md);
747 return r;
748 }
749
750 __hash_remove(hc);
751 up_write(&_hash_lock);
752
753 if (!dm_kobject_uevent(md, KOBJ_REMOVE, param->event_nr))
754 param->flags |= DM_UEVENT_GENERATED_FLAG;
755
756 dm_put(md);
757 dm_destroy(md);
758 return 0;
759 }
760
761 /*
762 * Check a string doesn't overrun the chunk of
763 * memory we copied from userland.
764 */
765 static int invalid_str(char *str, void *end)
766 {
767 while ((void *) str < end)
768 if (!*str++)
769 return 0;
770
771 return -EINVAL;
772 }
773
774 static int dev_rename(struct dm_ioctl *param, size_t param_size)
775 {
776 int r;
777 char *new_name = (char *) param + param->data_start;
778 struct mapped_device *md;
779
780 if (new_name < param->data ||
781 invalid_str(new_name, (void *) param + param_size) ||
782 strlen(new_name) > DM_NAME_LEN - 1) {
783 DMWARN("Invalid new logical volume name supplied.");
784 return -EINVAL;
785 }
786
787 r = check_name(new_name);
788 if (r)
789 return r;
790
791 md = dm_hash_rename(param, new_name);
792 if (IS_ERR(md))
793 return PTR_ERR(md);
794
795 __dev_status(md, param);
796 dm_put(md);
797
798 return 0;
799 }
800
801 static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
802 {
803 int r = -EINVAL, x;
804 struct mapped_device *md;
805 struct hd_geometry geometry;
806 unsigned long indata[4];
807 char *geostr = (char *) param + param->data_start;
808
809 md = find_device(param);
810 if (!md)
811 return -ENXIO;
812
813 if (geostr < param->data ||
814 invalid_str(geostr, (void *) param + param_size)) {
815 DMWARN("Invalid geometry supplied.");
816 goto out;
817 }
818
819 x = sscanf(geostr, "%lu %lu %lu %lu", indata,
820 indata + 1, indata + 2, indata + 3);
821
822 if (x != 4) {
823 DMWARN("Unable to interpret geometry settings.");
824 goto out;
825 }
826
827 if (indata[0] > 65535 || indata[1] > 255 ||
828 indata[2] > 255 || indata[3] > ULONG_MAX) {
829 DMWARN("Geometry exceeds range limits.");
830 goto out;
831 }
832
833 geometry.cylinders = indata[0];
834 geometry.heads = indata[1];
835 geometry.sectors = indata[2];
836 geometry.start = indata[3];
837
838 r = dm_set_geometry(md, &geometry);
839
840 param->data_size = 0;
841
842 out:
843 dm_put(md);
844 return r;
845 }
846
847 static int do_suspend(struct dm_ioctl *param)
848 {
849 int r = 0;
850 unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
851 struct mapped_device *md;
852
853 md = find_device(param);
854 if (!md)
855 return -ENXIO;
856
857 if (param->flags & DM_SKIP_LOCKFS_FLAG)
858 suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
859 if (param->flags & DM_NOFLUSH_FLAG)
860 suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
861
862 if (!dm_suspended_md(md)) {
863 r = dm_suspend(md, suspend_flags);
864 if (r)
865 goto out;
866 }
867
868 __dev_status(md, param);
869
870 out:
871 dm_put(md);
872
873 return r;
874 }
875
876 static int do_resume(struct dm_ioctl *param)
877 {
878 int r = 0;
879 unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
880 struct hash_cell *hc;
881 struct mapped_device *md;
882 struct dm_table *new_map, *old_map = NULL;
883
884 down_write(&_hash_lock);
885
886 hc = __find_device_hash_cell(param);
887 if (!hc) {
888 DMWARN("device doesn't appear to be in the dev hash table.");
889 up_write(&_hash_lock);
890 return -ENXIO;
891 }
892
893 md = hc->md;
894
895 new_map = hc->new_map;
896 hc->new_map = NULL;
897 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
898
899 up_write(&_hash_lock);
900
901 /* Do we need to load a new map ? */
902 if (new_map) {
903 /* Suspend if it isn't already suspended */
904 if (param->flags & DM_SKIP_LOCKFS_FLAG)
905 suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
906 if (param->flags & DM_NOFLUSH_FLAG)
907 suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
908 if (!dm_suspended_md(md))
909 dm_suspend(md, suspend_flags);
910
911 old_map = dm_swap_table(md, new_map);
912 if (IS_ERR(old_map)) {
913 dm_table_destroy(new_map);
914 dm_put(md);
915 return PTR_ERR(old_map);
916 }
917
918 if (dm_table_get_mode(new_map) & FMODE_WRITE)
919 set_disk_ro(dm_disk(md), 0);
920 else
921 set_disk_ro(dm_disk(md), 1);
922 }
923
924 if (dm_suspended_md(md)) {
925 r = dm_resume(md);
926 if (!r && !dm_kobject_uevent(md, KOBJ_CHANGE, param->event_nr))
927 param->flags |= DM_UEVENT_GENERATED_FLAG;
928 }
929
930 if (old_map)
931 dm_table_destroy(old_map);
932
933 if (!r)
934 __dev_status(md, param);
935
936 dm_put(md);
937 return r;
938 }
939
940 /*
941 * Set or unset the suspension state of a device.
942 * If the device already is in the requested state we just return its status.
943 */
944 static int dev_suspend(struct dm_ioctl *param, size_t param_size)
945 {
946 if (param->flags & DM_SUSPEND_FLAG)
947 return do_suspend(param);
948
949 return do_resume(param);
950 }
951
952 /*
953 * Copies device info back to user space, used by
954 * the create and info ioctls.
955 */
956 static int dev_status(struct dm_ioctl *param, size_t param_size)
957 {
958 struct mapped_device *md;
959
960 md = find_device(param);
961 if (!md)
962 return -ENXIO;
963
964 __dev_status(md, param);
965 dm_put(md);
966
967 return 0;
968 }
969
970 /*
971 * Build up the status struct for each target
972 */
973 static void retrieve_status(struct dm_table *table,
974 struct dm_ioctl *param, size_t param_size)
975 {
976 unsigned int i, num_targets;
977 struct dm_target_spec *spec;
978 char *outbuf, *outptr;
979 status_type_t type;
980 size_t remaining, len, used = 0;
981
982 outptr = outbuf = get_result_buffer(param, param_size, &len);
983
984 if (param->flags & DM_STATUS_TABLE_FLAG)
985 type = STATUSTYPE_TABLE;
986 else
987 type = STATUSTYPE_INFO;
988
989 /* Get all the target info */
990 num_targets = dm_table_get_num_targets(table);
991 for (i = 0; i < num_targets; i++) {
992 struct dm_target *ti = dm_table_get_target(table, i);
993
994 remaining = len - (outptr - outbuf);
995 if (remaining <= sizeof(struct dm_target_spec)) {
996 param->flags |= DM_BUFFER_FULL_FLAG;
997 break;
998 }
999
1000 spec = (struct dm_target_spec *) outptr;
1001
1002 spec->status = 0;
1003 spec->sector_start = ti->begin;
1004 spec->length = ti->len;
1005 strncpy(spec->target_type, ti->type->name,
1006 sizeof(spec->target_type));
1007
1008 outptr += sizeof(struct dm_target_spec);
1009 remaining = len - (outptr - outbuf);
1010 if (remaining <= 0) {
1011 param->flags |= DM_BUFFER_FULL_FLAG;
1012 break;
1013 }
1014
1015 /* Get the status/table string from the target driver */
1016 if (ti->type->status) {
1017 if (ti->type->status(ti, type, outptr, remaining)) {
1018 param->flags |= DM_BUFFER_FULL_FLAG;
1019 break;
1020 }
1021 } else
1022 outptr[0] = '\0';
1023
1024 outptr += strlen(outptr) + 1;
1025 used = param->data_start + (outptr - outbuf);
1026
1027 outptr = align_ptr(outptr);
1028 spec->next = outptr - outbuf;
1029 }
1030
1031 if (used)
1032 param->data_size = used;
1033
1034 param->target_count = num_targets;
1035 }
1036
1037 /*
1038 * Wait for a device to report an event
1039 */
1040 static int dev_wait(struct dm_ioctl *param, size_t param_size)
1041 {
1042 int r = 0;
1043 struct mapped_device *md;
1044 struct dm_table *table;
1045
1046 md = find_device(param);
1047 if (!md)
1048 return -ENXIO;
1049
1050 /*
1051 * Wait for a notification event
1052 */
1053 if (dm_wait_event(md, param->event_nr)) {
1054 r = -ERESTARTSYS;
1055 goto out;
1056 }
1057
1058 /*
1059 * The userland program is going to want to know what
1060 * changed to trigger the event, so we may as well tell
1061 * him and save an ioctl.
1062 */
1063 __dev_status(md, param);
1064
1065 table = dm_get_live_or_inactive_table(md, param);
1066 if (table) {
1067 retrieve_status(table, param, param_size);
1068 dm_table_put(table);
1069 }
1070
1071 out:
1072 dm_put(md);
1073
1074 return r;
1075 }
1076
1077 static inline fmode_t get_mode(struct dm_ioctl *param)
1078 {
1079 fmode_t mode = FMODE_READ | FMODE_WRITE;
1080
1081 if (param->flags & DM_READONLY_FLAG)
1082 mode = FMODE_READ;
1083
1084 return mode;
1085 }
1086
1087 static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
1088 struct dm_target_spec **spec, char **target_params)
1089 {
1090 *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
1091 *target_params = (char *) (*spec + 1);
1092
1093 if (*spec < (last + 1))
1094 return -EINVAL;
1095
1096 return invalid_str(*target_params, end);
1097 }
1098
1099 static int populate_table(struct dm_table *table,
1100 struct dm_ioctl *param, size_t param_size)
1101 {
1102 int r;
1103 unsigned int i = 0;
1104 struct dm_target_spec *spec = (struct dm_target_spec *) param;
1105 uint32_t next = param->data_start;
1106 void *end = (void *) param + param_size;
1107 char *target_params;
1108
1109 if (!param->target_count) {
1110 DMWARN("populate_table: no targets specified");
1111 return -EINVAL;
1112 }
1113
1114 for (i = 0; i < param->target_count; i++) {
1115
1116 r = next_target(spec, next, end, &spec, &target_params);
1117 if (r) {
1118 DMWARN("unable to find target");
1119 return r;
1120 }
1121
1122 r = dm_table_add_target(table, spec->target_type,
1123 (sector_t) spec->sector_start,
1124 (sector_t) spec->length,
1125 target_params);
1126 if (r) {
1127 DMWARN("error adding target to table");
1128 return r;
1129 }
1130
1131 next = spec->next;
1132 }
1133
1134 return dm_table_complete(table);
1135 }
1136
1137 static int table_load(struct dm_ioctl *param, size_t param_size)
1138 {
1139 int r;
1140 struct hash_cell *hc;
1141 struct dm_table *t;
1142 struct mapped_device *md;
1143
1144 md = find_device(param);
1145 if (!md)
1146 return -ENXIO;
1147
1148 r = dm_table_create(&t, get_mode(param), param->target_count, md);
1149 if (r)
1150 goto out;
1151
1152 r = populate_table(t, param, param_size);
1153 if (r) {
1154 dm_table_destroy(t);
1155 goto out;
1156 }
1157
1158 /* Protect md->type and md->queue against concurrent table loads. */
1159 dm_lock_md_type(md);
1160 if (dm_get_md_type(md) == DM_TYPE_NONE)
1161 /* Initial table load: acquire type of table. */
1162 dm_set_md_type(md, dm_table_get_type(t));
1163 else if (dm_get_md_type(md) != dm_table_get_type(t)) {
1164 DMWARN("can't change device type after initial table load.");
1165 dm_table_destroy(t);
1166 dm_unlock_md_type(md);
1167 r = -EINVAL;
1168 goto out;
1169 }
1170
1171 /* setup md->queue to reflect md's type (may block) */
1172 r = dm_setup_md_queue(md);
1173 if (r) {
1174 DMWARN("unable to set up device queue for new table.");
1175 dm_table_destroy(t);
1176 dm_unlock_md_type(md);
1177 goto out;
1178 }
1179 dm_unlock_md_type(md);
1180
1181 /* stage inactive table */
1182 down_write(&_hash_lock);
1183 hc = dm_get_mdptr(md);
1184 if (!hc || hc->md != md) {
1185 DMWARN("device has been removed from the dev hash table.");
1186 dm_table_destroy(t);
1187 up_write(&_hash_lock);
1188 r = -ENXIO;
1189 goto out;
1190 }
1191
1192 if (hc->new_map)
1193 dm_table_destroy(hc->new_map);
1194 hc->new_map = t;
1195 up_write(&_hash_lock);
1196
1197 param->flags |= DM_INACTIVE_PRESENT_FLAG;
1198 __dev_status(md, param);
1199
1200 out:
1201 dm_put(md);
1202
1203 return r;
1204 }
1205
1206 static int table_clear(struct dm_ioctl *param, size_t param_size)
1207 {
1208 struct hash_cell *hc;
1209 struct mapped_device *md;
1210
1211 down_write(&_hash_lock);
1212
1213 hc = __find_device_hash_cell(param);
1214 if (!hc) {
1215 DMWARN("device doesn't appear to be in the dev hash table.");
1216 up_write(&_hash_lock);
1217 return -ENXIO;
1218 }
1219
1220 if (hc->new_map) {
1221 dm_table_destroy(hc->new_map);
1222 hc->new_map = NULL;
1223 }
1224
1225 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
1226
1227 __dev_status(hc->md, param);
1228 md = hc->md;
1229 up_write(&_hash_lock);
1230 dm_put(md);
1231
1232 return 0;
1233 }
1234
1235 /*
1236 * Retrieves a list of devices used by a particular dm device.
1237 */
1238 static void retrieve_deps(struct dm_table *table,
1239 struct dm_ioctl *param, size_t param_size)
1240 {
1241 unsigned int count = 0;
1242 struct list_head *tmp;
1243 size_t len, needed;
1244 struct dm_dev_internal *dd;
1245 struct dm_target_deps *deps;
1246
1247 deps = get_result_buffer(param, param_size, &len);
1248
1249 /*
1250 * Count the devices.
1251 */
1252 list_for_each (tmp, dm_table_get_devices(table))
1253 count++;
1254
1255 /*
1256 * Check we have enough space.
1257 */
1258 needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
1259 if (len < needed) {
1260 param->flags |= DM_BUFFER_FULL_FLAG;
1261 return;
1262 }
1263
1264 /*
1265 * Fill in the devices.
1266 */
1267 deps->count = count;
1268 count = 0;
1269 list_for_each_entry (dd, dm_table_get_devices(table), list)
1270 deps->dev[count++] = huge_encode_dev(dd->dm_dev.bdev->bd_dev);
1271
1272 param->data_size = param->data_start + needed;
1273 }
1274
1275 static int table_deps(struct dm_ioctl *param, size_t param_size)
1276 {
1277 struct mapped_device *md;
1278 struct dm_table *table;
1279
1280 md = find_device(param);
1281 if (!md)
1282 return -ENXIO;
1283
1284 __dev_status(md, param);
1285
1286 table = dm_get_live_or_inactive_table(md, param);
1287 if (table) {
1288 retrieve_deps(table, param, param_size);
1289 dm_table_put(table);
1290 }
1291
1292 dm_put(md);
1293
1294 return 0;
1295 }
1296
1297 /*
1298 * Return the status of a device as a text string for each
1299 * target.
1300 */
1301 static int table_status(struct dm_ioctl *param, size_t param_size)
1302 {
1303 struct mapped_device *md;
1304 struct dm_table *table;
1305
1306 md = find_device(param);
1307 if (!md)
1308 return -ENXIO;
1309
1310 __dev_status(md, param);
1311
1312 table = dm_get_live_or_inactive_table(md, param);
1313 if (table) {
1314 retrieve_status(table, param, param_size);
1315 dm_table_put(table);
1316 }
1317
1318 dm_put(md);
1319
1320 return 0;
1321 }
1322
1323 /*
1324 * Pass a message to the target that's at the supplied device offset.
1325 */
1326 static int target_message(struct dm_ioctl *param, size_t param_size)
1327 {
1328 int r, argc;
1329 char **argv;
1330 struct mapped_device *md;
1331 struct dm_table *table;
1332 struct dm_target *ti;
1333 struct dm_target_msg *tmsg = (void *) param + param->data_start;
1334
1335 md = find_device(param);
1336 if (!md)
1337 return -ENXIO;
1338
1339 if (tmsg < (struct dm_target_msg *) param->data ||
1340 invalid_str(tmsg->message, (void *) param + param_size)) {
1341 DMWARN("Invalid target message parameters.");
1342 r = -EINVAL;
1343 goto out;
1344 }
1345
1346 r = dm_split_args(&argc, &argv, tmsg->message);
1347 if (r) {
1348 DMWARN("Failed to split target message parameters");
1349 goto out;
1350 }
1351
1352 table = dm_get_live_table(md);
1353 if (!table)
1354 goto out_argv;
1355
1356 if (dm_deleting_md(md)) {
1357 r = -ENXIO;
1358 goto out_table;
1359 }
1360
1361 ti = dm_table_find_target(table, tmsg->sector);
1362 if (!dm_target_is_valid(ti)) {
1363 DMWARN("Target message sector outside device.");
1364 r = -EINVAL;
1365 } else if (ti->type->message)
1366 r = ti->type->message(ti, argc, argv);
1367 else {
1368 DMWARN("Target type does not support messages");
1369 r = -EINVAL;
1370 }
1371
1372 out_table:
1373 dm_table_put(table);
1374 out_argv:
1375 kfree(argv);
1376 out:
1377 param->data_size = 0;
1378 dm_put(md);
1379 return r;
1380 }
1381
1382 /*-----------------------------------------------------------------
1383 * Implementation of open/close/ioctl on the special char
1384 * device.
1385 *---------------------------------------------------------------*/
1386 static ioctl_fn lookup_ioctl(unsigned int cmd)
1387 {
1388 static struct {
1389 int cmd;
1390 ioctl_fn fn;
1391 } _ioctls[] = {
1392 {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
1393 {DM_REMOVE_ALL_CMD, remove_all},
1394 {DM_LIST_DEVICES_CMD, list_devices},
1395
1396 {DM_DEV_CREATE_CMD, dev_create},
1397 {DM_DEV_REMOVE_CMD, dev_remove},
1398 {DM_DEV_RENAME_CMD, dev_rename},
1399 {DM_DEV_SUSPEND_CMD, dev_suspend},
1400 {DM_DEV_STATUS_CMD, dev_status},
1401 {DM_DEV_WAIT_CMD, dev_wait},
1402
1403 {DM_TABLE_LOAD_CMD, table_load},
1404 {DM_TABLE_CLEAR_CMD, table_clear},
1405 {DM_TABLE_DEPS_CMD, table_deps},
1406 {DM_TABLE_STATUS_CMD, table_status},
1407
1408 {DM_LIST_VERSIONS_CMD, list_versions},
1409
1410 {DM_TARGET_MSG_CMD, target_message},
1411 {DM_DEV_SET_GEOMETRY_CMD, dev_set_geometry}
1412 };
1413
1414 return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
1415 }
1416
1417 /*
1418 * As well as checking the version compatibility this always
1419 * copies the kernel interface version out.
1420 */
1421 static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
1422 {
1423 uint32_t version[3];
1424 int r = 0;
1425
1426 if (copy_from_user(version, user->version, sizeof(version)))
1427 return -EFAULT;
1428
1429 if ((DM_VERSION_MAJOR != version[0]) ||
1430 (DM_VERSION_MINOR < version[1])) {
1431 DMWARN("ioctl interface mismatch: "
1432 "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
1433 DM_VERSION_MAJOR, DM_VERSION_MINOR,
1434 DM_VERSION_PATCHLEVEL,
1435 version[0], version[1], version[2], cmd);
1436 r = -EINVAL;
1437 }
1438
1439 /*
1440 * Fill in the kernel version.
1441 */
1442 version[0] = DM_VERSION_MAJOR;
1443 version[1] = DM_VERSION_MINOR;
1444 version[2] = DM_VERSION_PATCHLEVEL;
1445 if (copy_to_user(user->version, version, sizeof(version)))
1446 return -EFAULT;
1447
1448 return r;
1449 }
1450
1451 static void free_params(struct dm_ioctl *param)
1452 {
1453 vfree(param);
1454 }
1455
1456 static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
1457 {
1458 struct dm_ioctl tmp, *dmi;
1459
1460 if (copy_from_user(&tmp, user, sizeof(tmp) - sizeof(tmp.data)))
1461 return -EFAULT;
1462
1463 if (tmp.data_size < (sizeof(tmp) - sizeof(tmp.data)))
1464 return -EINVAL;
1465
1466 dmi = vmalloc(tmp.data_size);
1467 if (!dmi)
1468 return -ENOMEM;
1469
1470 if (copy_from_user(dmi, user, tmp.data_size)) {
1471 vfree(dmi);
1472 return -EFAULT;
1473 }
1474
1475 *param = dmi;
1476 return 0;
1477 }
1478
1479 static int validate_params(uint cmd, struct dm_ioctl *param)
1480 {
1481 /* Always clear this flag */
1482 param->flags &= ~DM_BUFFER_FULL_FLAG;
1483 param->flags &= ~DM_UEVENT_GENERATED_FLAG;
1484
1485 /* Ignores parameters */
1486 if (cmd == DM_REMOVE_ALL_CMD ||
1487 cmd == DM_LIST_DEVICES_CMD ||
1488 cmd == DM_LIST_VERSIONS_CMD)
1489 return 0;
1490
1491 if ((cmd == DM_DEV_CREATE_CMD)) {
1492 if (!*param->name) {
1493 DMWARN("name not supplied when creating device");
1494 return -EINVAL;
1495 }
1496 } else if ((*param->uuid && *param->name)) {
1497 DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
1498 return -EINVAL;
1499 }
1500
1501 /* Ensure strings are terminated */
1502 param->name[DM_NAME_LEN - 1] = '\0';
1503 param->uuid[DM_UUID_LEN - 1] = '\0';
1504
1505 return 0;
1506 }
1507
1508 static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
1509 {
1510 int r = 0;
1511 unsigned int cmd;
1512 struct dm_ioctl *uninitialized_var(param);
1513 ioctl_fn fn = NULL;
1514 size_t param_size;
1515
1516 /* only root can play with this */
1517 if (!capable(CAP_SYS_ADMIN))
1518 return -EACCES;
1519
1520 if (_IOC_TYPE(command) != DM_IOCTL)
1521 return -ENOTTY;
1522
1523 cmd = _IOC_NR(command);
1524
1525 /*
1526 * Check the interface version passed in. This also
1527 * writes out the kernel's interface version.
1528 */
1529 r = check_version(cmd, user);
1530 if (r)
1531 return r;
1532
1533 /*
1534 * Nothing more to do for the version command.
1535 */
1536 if (cmd == DM_VERSION_CMD)
1537 return 0;
1538
1539 fn = lookup_ioctl(cmd);
1540 if (!fn) {
1541 DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
1542 return -ENOTTY;
1543 }
1544
1545 /*
1546 * Trying to avoid low memory issues when a device is
1547 * suspended.
1548 */
1549 current->flags |= PF_MEMALLOC;
1550
1551 /*
1552 * Copy the parameters into kernel space.
1553 */
1554 r = copy_params(user, &param);
1555
1556 current->flags &= ~PF_MEMALLOC;
1557
1558 if (r)
1559 return r;
1560
1561 r = validate_params(cmd, param);
1562 if (r)
1563 goto out;
1564
1565 param_size = param->data_size;
1566 param->data_size = sizeof(*param);
1567 r = fn(param, param_size);
1568
1569 /*
1570 * Copy the results back to userland.
1571 */
1572 if (!r && copy_to_user(user, param, param->data_size))
1573 r = -EFAULT;
1574
1575 out:
1576 free_params(param);
1577 return r;
1578 }
1579
1580 static long dm_ctl_ioctl(struct file *file, uint command, ulong u)
1581 {
1582 return (long)ctl_ioctl(command, (struct dm_ioctl __user *)u);
1583 }
1584
1585 #ifdef CONFIG_COMPAT
1586 static long dm_compat_ctl_ioctl(struct file *file, uint command, ulong u)
1587 {
1588 return (long)dm_ctl_ioctl(file, command, (ulong) compat_ptr(u));
1589 }
1590 #else
1591 #define dm_compat_ctl_ioctl NULL
1592 #endif
1593
1594 static const struct file_operations _ctl_fops = {
1595 .open = nonseekable_open,
1596 .unlocked_ioctl = dm_ctl_ioctl,
1597 .compat_ioctl = dm_compat_ctl_ioctl,
1598 .owner = THIS_MODULE,
1599 };
1600
1601 static struct miscdevice _dm_misc = {
1602 .minor = MAPPER_CTRL_MINOR,
1603 .name = DM_NAME,
1604 .nodename = DM_DIR "/" DM_CONTROL_NODE,
1605 .fops = &_ctl_fops
1606 };
1607
1608 MODULE_ALIAS_MISCDEV(MAPPER_CTRL_MINOR);
1609 MODULE_ALIAS("devname:" DM_DIR "/" DM_CONTROL_NODE);
1610
1611 /*
1612 * Create misc character device and link to DM_DIR/control.
1613 */
1614 int __init dm_interface_init(void)
1615 {
1616 int r;
1617
1618 r = dm_hash_init();
1619 if (r)
1620 return r;
1621
1622 r = misc_register(&_dm_misc);
1623 if (r) {
1624 DMERR("misc_register failed for control device");
1625 dm_hash_exit();
1626 return r;
1627 }
1628
1629 DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
1630 DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
1631 DM_DRIVER_EMAIL);
1632 return 0;
1633 }
1634
1635 void dm_interface_exit(void)
1636 {
1637 if (misc_deregister(&_dm_misc) < 0)
1638 DMERR("misc_deregister failed for control device");
1639
1640 dm_hash_exit();
1641 }
1642
1643 /**
1644 * dm_copy_name_and_uuid - Copy mapped device name & uuid into supplied buffers
1645 * @md: Pointer to mapped_device
1646 * @name: Buffer (size DM_NAME_LEN) for name
1647 * @uuid: Buffer (size DM_UUID_LEN) for uuid or empty string if uuid not defined
1648 */
1649 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
1650 {
1651 int r = 0;
1652 struct hash_cell *hc;
1653
1654 if (!md)
1655 return -ENXIO;
1656
1657 mutex_lock(&dm_hash_cells_mutex);
1658 hc = dm_get_mdptr(md);
1659 if (!hc || hc->md != md) {
1660 r = -ENXIO;
1661 goto out;
1662 }
1663
1664 if (name)
1665 strcpy(name, hc->name);
1666 if (uuid)
1667 strcpy(uuid, hc->uuid ? : "");
1668
1669 out:
1670 mutex_unlock(&dm_hash_cells_mutex);
1671
1672 return r;
1673 }
Tomato firmware and modifications.