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fs: use kmem_cache_zalloc instead
[pv_ops_mirror.git] / drivers / md / dm-ioctl.c
blobb441d82c338a32156a6d270eaa1f7cb5553178f9
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
19 #include <asm/uaccess.h>
20
21 #define DM_MSG_PREFIX "ioctl"
22 #define DM_DRIVER_EMAIL "dm-devel@redhat.com"
23
24 /*-----------------------------------------------------------------
25 * The ioctl interface needs to be able to look up devices by
26 * name or uuid.
27 *---------------------------------------------------------------*/
28 struct hash_cell {
29 struct list_head name_list;
30 struct list_head uuid_list;
31
32 char *name;
33 char *uuid;
34 struct mapped_device *md;
35 struct dm_table *new_map;
36 };
37
38 struct vers_iter {
39 size_t param_size;
40 struct dm_target_versions *vers, *old_vers;
41 char *end;
42 uint32_t flags;
43 };
44
45
46 #define NUM_BUCKETS 64
47 #define MASK_BUCKETS (NUM_BUCKETS - 1)
48 static struct list_head _name_buckets[NUM_BUCKETS];
49 static struct list_head _uuid_buckets[NUM_BUCKETS];
50
51 static void dm_hash_remove_all(int keep_open_devices);
52
53 /*
54 * Guards access to both hash tables.
55 */
56 static DECLARE_RWSEM(_hash_lock);
57
58 static void init_buckets(struct list_head *buckets)
59 {
60 unsigned int i;
61
62 for (i = 0; i < NUM_BUCKETS; i++)
63 INIT_LIST_HEAD(buckets + i);
64 }
65
66 static int dm_hash_init(void)
67 {
68 init_buckets(_name_buckets);
69 init_buckets(_uuid_buckets);
70 return 0;
71 }
72
73 static void dm_hash_exit(void)
74 {
75 dm_hash_remove_all(0);
76 }
77
78 /*-----------------------------------------------------------------
79 * Hash function:
80 * We're not really concerned with the str hash function being
81 * fast since it's only used by the ioctl interface.
82 *---------------------------------------------------------------*/
83 static unsigned int hash_str(const char *str)
84 {
85 const unsigned int hash_mult = 2654435387U;
86 unsigned int h = 0;
87
88 while (*str)
89 h = (h + (unsigned int) *str++) * hash_mult;
90
91 return h & MASK_BUCKETS;
92 }
93
94 /*-----------------------------------------------------------------
95 * Code for looking up a device by name
96 *---------------------------------------------------------------*/
97 static struct hash_cell *__get_name_cell(const char *str)
98 {
99 struct hash_cell *hc;
100 unsigned int h = hash_str(str);
101
102 list_for_each_entry (hc, _name_buckets + h, name_list)
103 if (!strcmp(hc->name, str)) {
104 dm_get(hc->md);
105 return hc;
106 }
107
108 return NULL;
109 }
110
111 static struct hash_cell *__get_uuid_cell(const char *str)
112 {
113 struct hash_cell *hc;
114 unsigned int h = hash_str(str);
115
116 list_for_each_entry (hc, _uuid_buckets + h, uuid_list)
117 if (!strcmp(hc->uuid, str)) {
118 dm_get(hc->md);
119 return hc;
120 }
121
122 return NULL;
123 }
124
125 /*-----------------------------------------------------------------
126 * Inserting, removing and renaming a device.
127 *---------------------------------------------------------------*/
128 static struct hash_cell *alloc_cell(const char *name, const char *uuid,
129 struct mapped_device *md)
130 {
131 struct hash_cell *hc;
132
133 hc = kmalloc(sizeof(*hc), GFP_KERNEL);
134 if (!hc)
135 return NULL;
136
137 hc->name = kstrdup(name, GFP_KERNEL);
138 if (!hc->name) {
139 kfree(hc);
140 return NULL;
141 }
142
143 if (!uuid)
144 hc->uuid = NULL;
145
146 else {
147 hc->uuid = kstrdup(uuid, GFP_KERNEL);
148 if (!hc->uuid) {
149 kfree(hc->name);
150 kfree(hc);
151 return NULL;
152 }
153 }
154
155 INIT_LIST_HEAD(&hc->name_list);
156 INIT_LIST_HEAD(&hc->uuid_list);
157 hc->md = md;
158 hc->new_map = NULL;
159 return hc;
160 }
161
162 static void free_cell(struct hash_cell *hc)
163 {
164 if (hc) {
165 kfree(hc->name);
166 kfree(hc->uuid);
167 kfree(hc);
168 }
169 }
170
171 /*
172 * The kdev_t and uuid of a device can never change once it is
173 * initially inserted.
174 */
175 static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md)
176 {
177 struct hash_cell *cell, *hc;
178
179 /*
180 * Allocate the new cells.
181 */
182 cell = alloc_cell(name, uuid, md);
183 if (!cell)
184 return -ENOMEM;
185
186 /*
187 * Insert the cell into both hash tables.
188 */
189 down_write(&_hash_lock);
190 hc = __get_name_cell(name);
191 if (hc) {
192 dm_put(hc->md);
193 goto bad;
194 }
195
196 list_add(&cell->name_list, _name_buckets + hash_str(name));
197
198 if (uuid) {
199 hc = __get_uuid_cell(uuid);
200 if (hc) {
201 list_del(&cell->name_list);
202 dm_put(hc->md);
203 goto bad;
204 }
205 list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
206 }
207 dm_get(md);
208 dm_set_mdptr(md, cell);
209 up_write(&_hash_lock);
210
211 return 0;
212
213 bad:
214 up_write(&_hash_lock);
215 free_cell(cell);
216 return -EBUSY;
217 }
218
219 static void __hash_remove(struct hash_cell *hc)
220 {
221 struct dm_table *table;
222
223 /* remove from the dev hash */
224 list_del(&hc->uuid_list);
225 list_del(&hc->name_list);
226 dm_set_mdptr(hc->md, NULL);
227
228 table = dm_get_table(hc->md);
229 if (table) {
230 dm_table_event(table);
231 dm_table_put(table);
232 }
233
234 if (hc->new_map)
235 dm_table_put(hc->new_map);
236 dm_put(hc->md);
237 free_cell(hc);
238 }
239
240 static void dm_hash_remove_all(int keep_open_devices)
241 {
242 int i, dev_skipped, dev_removed;
243 struct hash_cell *hc;
244 struct list_head *tmp, *n;
245
246 down_write(&_hash_lock);
247
248 retry:
249 dev_skipped = dev_removed = 0;
250 for (i = 0; i < NUM_BUCKETS; i++) {
251 list_for_each_safe (tmp, n, _name_buckets + i) {
252 hc = list_entry(tmp, struct hash_cell, name_list);
253
254 if (keep_open_devices &&
255 dm_lock_for_deletion(hc->md)) {
256 dev_skipped++;
257 continue;
258 }
259 __hash_remove(hc);
260 dev_removed = 1;
261 }
262 }
263
264 /*
265 * Some mapped devices may be using other mapped devices, so if any
266 * still exist, repeat until we make no further progress.
267 */
268 if (dev_skipped) {
269 if (dev_removed)
270 goto retry;
271
272 DMWARN("remove_all left %d open device(s)", dev_skipped);
273 }
274
275 up_write(&_hash_lock);
276 }
277
278 static int dm_hash_rename(const char *old, const char *new)
279 {
280 char *new_name, *old_name;
281 struct hash_cell *hc;
282 struct dm_table *table;
283
284 /*
285 * duplicate new.
286 */
287 new_name = kstrdup(new, GFP_KERNEL);
288 if (!new_name)
289 return -ENOMEM;
290
291 down_write(&_hash_lock);
292
293 /*
294 * Is new free ?
295 */
296 hc = __get_name_cell(new);
297 if (hc) {
298 DMWARN("asked to rename to an already existing name %s -> %s",
299 old, new);
300 dm_put(hc->md);
301 up_write(&_hash_lock);
302 kfree(new_name);
303 return -EBUSY;
304 }
305
306 /*
307 * Is there such a device as 'old' ?
308 */
309 hc = __get_name_cell(old);
310 if (!hc) {
311 DMWARN("asked to rename a non existent device %s -> %s",
312 old, new);
313 up_write(&_hash_lock);
314 kfree(new_name);
315 return -ENXIO;
316 }
317
318 /*
319 * rename and move the name cell.
320 */
321 list_del(&hc->name_list);
322 old_name = hc->name;
323 hc->name = new_name;
324 list_add(&hc->name_list, _name_buckets + hash_str(new_name));
325
326 /*
327 * Wake up any dm event waiters.
328 */
329 table = dm_get_table(hc->md);
330 if (table) {
331 dm_table_event(table);
332 dm_table_put(table);
333 }
334
335 dm_put(hc->md);
336 up_write(&_hash_lock);
337 kfree(old_name);
338 return 0;
339 }
340
341 /*-----------------------------------------------------------------
342 * Implementation of the ioctl commands
343 *---------------------------------------------------------------*/
344 /*
345 * All the ioctl commands get dispatched to functions with this
346 * prototype.
347 */
348 typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
349
350 static int remove_all(struct dm_ioctl *param, size_t param_size)
351 {
352 dm_hash_remove_all(1);
353 param->data_size = 0;
354 return 0;
355 }
356
357 /*
358 * Round up the ptr to an 8-byte boundary.
359 */
360 #define ALIGN_MASK 7
361 static inline void *align_ptr(void *ptr)
362 {
363 return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
364 }
365
366 /*
367 * Retrieves the data payload buffer from an already allocated
368 * struct dm_ioctl.
369 */
370 static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
371 size_t *len)
372 {
373 param->data_start = align_ptr(param + 1) - (void *) param;
374
375 if (param->data_start < param_size)
376 *len = param_size - param->data_start;
377 else
378 *len = 0;
379
380 return ((void *) param) + param->data_start;
381 }
382
383 static int list_devices(struct dm_ioctl *param, size_t param_size)
384 {
385 unsigned int i;
386 struct hash_cell *hc;
387 size_t len, needed = 0;
388 struct gendisk *disk;
389 struct dm_name_list *nl, *old_nl = NULL;
390
391 down_write(&_hash_lock);
392
393 /*
394 * Loop through all the devices working out how much
395 * space we need.
396 */
397 for (i = 0; i < NUM_BUCKETS; i++) {
398 list_for_each_entry (hc, _name_buckets + i, name_list) {
399 needed += sizeof(struct dm_name_list);
400 needed += strlen(hc->name) + 1;
401 needed += ALIGN_MASK;
402 }
403 }
404
405 /*
406 * Grab our output buffer.
407 */
408 nl = get_result_buffer(param, param_size, &len);
409 if (len < needed) {
410 param->flags |= DM_BUFFER_FULL_FLAG;
411 goto out;
412 }
413 param->data_size = param->data_start + needed;
414
415 nl->dev = 0; /* Flags no data */
416
417 /*
418 * Now loop through filling out the names.
419 */
420 for (i = 0; i < NUM_BUCKETS; i++) {
421 list_for_each_entry (hc, _name_buckets + i, name_list) {
422 if (old_nl)
423 old_nl->next = (uint32_t) ((void *) nl -
424 (void *) old_nl);
425 disk = dm_disk(hc->md);
426 nl->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
427 nl->next = 0;
428 strcpy(nl->name, hc->name);
429
430 old_nl = nl;
431 nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
432 }
433 }
434
435 out:
436 up_write(&_hash_lock);
437 return 0;
438 }
439
440 static void list_version_get_needed(struct target_type *tt, void *needed_param)
441 {
442 size_t *needed = needed_param;
443
444 *needed += sizeof(struct dm_target_versions);
445 *needed += strlen(tt->name);
446 *needed += ALIGN_MASK;
447 }
448
449 static void list_version_get_info(struct target_type *tt, void *param)
450 {
451 struct vers_iter *info = param;
452
453 /* Check space - it might have changed since the first iteration */
454 if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
455 info->end) {
456
457 info->flags = DM_BUFFER_FULL_FLAG;
458 return;
459 }
460
461 if (info->old_vers)
462 info->old_vers->next = (uint32_t) ((void *)info->vers -
463 (void *)info->old_vers);
464 info->vers->version[0] = tt->version[0];
465 info->vers->version[1] = tt->version[1];
466 info->vers->version[2] = tt->version[2];
467 info->vers->next = 0;
468 strcpy(info->vers->name, tt->name);
469
470 info->old_vers = info->vers;
471 info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
472 }
473
474 static int list_versions(struct dm_ioctl *param, size_t param_size)
475 {
476 size_t len, needed = 0;
477 struct dm_target_versions *vers;
478 struct vers_iter iter_info;
479
480 /*
481 * Loop through all the devices working out how much
482 * space we need.
483 */
484 dm_target_iterate(list_version_get_needed, &needed);
485
486 /*
487 * Grab our output buffer.
488 */
489 vers = get_result_buffer(param, param_size, &len);
490 if (len < needed) {
491 param->flags |= DM_BUFFER_FULL_FLAG;
492 goto out;
493 }
494 param->data_size = param->data_start + needed;
495
496 iter_info.param_size = param_size;
497 iter_info.old_vers = NULL;
498 iter_info.vers = vers;
499 iter_info.flags = 0;
500 iter_info.end = (char *)vers+len;
501
502 /*
503 * Now loop through filling out the names & versions.
504 */
505 dm_target_iterate(list_version_get_info, &iter_info);
506 param->flags |= iter_info.flags;
507
508 out:
509 return 0;
510 }
511
512
513
514 static int check_name(const char *name)
515 {
516 if (strchr(name, '/')) {
517 DMWARN("invalid device name");
518 return -EINVAL;
519 }
520
521 return 0;
522 }
523
524 /*
525 * Fills in a dm_ioctl structure, ready for sending back to
526 * userland.
527 */
528 static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
529 {
530 struct gendisk *disk = dm_disk(md);
531 struct dm_table *table;
532
533 param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
534 DM_ACTIVE_PRESENT_FLAG);
535
536 if (dm_suspended(md))
537 param->flags |= DM_SUSPEND_FLAG;
538
539 param->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
540
541 /*
542 * Yes, this will be out of date by the time it gets back
543 * to userland, but it is still very useful for
544 * debugging.
545 */
546 param->open_count = dm_open_count(md);
547
548 if (disk->policy)
549 param->flags |= DM_READONLY_FLAG;
550
551 param->event_nr = dm_get_event_nr(md);
552
553 table = dm_get_table(md);
554 if (table) {
555 param->flags |= DM_ACTIVE_PRESENT_FLAG;
556 param->target_count = dm_table_get_num_targets(table);
557 dm_table_put(table);
558 } else
559 param->target_count = 0;
560
561 return 0;
562 }
563
564 static int dev_create(struct dm_ioctl *param, size_t param_size)
565 {
566 int r, m = DM_ANY_MINOR;
567 struct mapped_device *md;
568
569 r = check_name(param->name);
570 if (r)
571 return r;
572
573 if (param->flags & DM_PERSISTENT_DEV_FLAG)
574 m = MINOR(huge_decode_dev(param->dev));
575
576 r = dm_create(m, &md);
577 if (r)
578 return r;
579
580 r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
581 if (r) {
582 dm_put(md);
583 return r;
584 }
585
586 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
587
588 r = __dev_status(md, param);
589 dm_put(md);
590
591 return r;
592 }
593
594 /*
595 * Always use UUID for lookups if it's present, otherwise use name or dev.
596 */
597 static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
598 {
599 struct mapped_device *md;
600 void *mdptr = NULL;
601
602 if (*param->uuid)
603 return __get_uuid_cell(param->uuid);
604
605 if (*param->name)
606 return __get_name_cell(param->name);
607
608 md = dm_get_md(huge_decode_dev(param->dev));
609 if (!md)
610 goto out;
611
612 mdptr = dm_get_mdptr(md);
613 if (!mdptr)
614 dm_put(md);
615
616 out:
617 return mdptr;
618 }
619
620 static struct mapped_device *find_device(struct dm_ioctl *param)
621 {
622 struct hash_cell *hc;
623 struct mapped_device *md = NULL;
624
625 down_read(&_hash_lock);
626 hc = __find_device_hash_cell(param);
627 if (hc) {
628 md = hc->md;
629
630 /*
631 * Sneakily write in both the name and the uuid
632 * while we have the cell.
633 */
634 strncpy(param->name, hc->name, sizeof(param->name));
635 if (hc->uuid)
636 strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
637 else
638 param->uuid[0] = '\0';
639
640 if (hc->new_map)
641 param->flags |= DM_INACTIVE_PRESENT_FLAG;
642 else
643 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
644 }
645 up_read(&_hash_lock);
646
647 return md;
648 }
649
650 static int dev_remove(struct dm_ioctl *param, size_t param_size)
651 {
652 struct hash_cell *hc;
653 struct mapped_device *md;
654 int r;
655
656 down_write(&_hash_lock);
657 hc = __find_device_hash_cell(param);
658
659 if (!hc) {
660 DMWARN("device doesn't appear to be in the dev hash table.");
661 up_write(&_hash_lock);
662 return -ENXIO;
663 }
664
665 md = hc->md;
666
667 /*
668 * Ensure the device is not open and nothing further can open it.
669 */
670 r = dm_lock_for_deletion(md);
671 if (r) {
672 DMWARN("unable to remove open device %s", hc->name);
673 up_write(&_hash_lock);
674 dm_put(md);
675 return r;
676 }
677
678 __hash_remove(hc);
679 up_write(&_hash_lock);
680 dm_put(md);
681 param->data_size = 0;
682 return 0;
683 }
684
685 /*
686 * Check a string doesn't overrun the chunk of
687 * memory we copied from userland.
688 */
689 static int invalid_str(char *str, void *end)
690 {
691 while ((void *) str < end)
692 if (!*str++)
693 return 0;
694
695 return -EINVAL;
696 }
697
698 static int dev_rename(struct dm_ioctl *param, size_t param_size)
699 {
700 int r;
701 char *new_name = (char *) param + param->data_start;
702
703 if (new_name < (char *) (param + 1) ||
704 invalid_str(new_name, (void *) param + param_size)) {
705 DMWARN("Invalid new logical volume name supplied.");
706 return -EINVAL;
707 }
708
709 r = check_name(new_name);
710 if (r)
711 return r;
712
713 param->data_size = 0;
714 return dm_hash_rename(param->name, new_name);
715 }
716
717 static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
718 {
719 int r = -EINVAL, x;
720 struct mapped_device *md;
721 struct hd_geometry geometry;
722 unsigned long indata[4];
723 char *geostr = (char *) param + param->data_start;
724
725 md = find_device(param);
726 if (!md)
727 return -ENXIO;
728
729 if (geostr < (char *) (param + 1) ||
730 invalid_str(geostr, (void *) param + param_size)) {
731 DMWARN("Invalid geometry supplied.");
732 goto out;
733 }
734
735 x = sscanf(geostr, "%lu %lu %lu %lu", indata,
736 indata + 1, indata + 2, indata + 3);
737
738 if (x != 4) {
739 DMWARN("Unable to interpret geometry settings.");
740 goto out;
741 }
742
743 if (indata[0] > 65535 || indata[1] > 255 ||
744 indata[2] > 255 || indata[3] > ULONG_MAX) {
745 DMWARN("Geometry exceeds range limits.");
746 goto out;
747 }
748
749 geometry.cylinders = indata[0];
750 geometry.heads = indata[1];
751 geometry.sectors = indata[2];
752 geometry.start = indata[3];
753
754 r = dm_set_geometry(md, &geometry);
755 if (!r)
756 r = __dev_status(md, param);
757
758 param->data_size = 0;
759
760 out:
761 dm_put(md);
762 return r;
763 }
764
765 static int do_suspend(struct dm_ioctl *param)
766 {
767 int r = 0;
768 unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
769 struct mapped_device *md;
770
771 md = find_device(param);
772 if (!md)
773 return -ENXIO;
774
775 if (param->flags & DM_SKIP_LOCKFS_FLAG)
776 suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
777 if (param->flags & DM_NOFLUSH_FLAG)
778 suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
779
780 if (!dm_suspended(md))
781 r = dm_suspend(md, suspend_flags);
782
783 if (!r)
784 r = __dev_status(md, param);
785
786 dm_put(md);
787 return r;
788 }
789
790 static int do_resume(struct dm_ioctl *param)
791 {
792 int r = 0;
793 unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
794 struct hash_cell *hc;
795 struct mapped_device *md;
796 struct dm_table *new_map;
797
798 down_write(&_hash_lock);
799
800 hc = __find_device_hash_cell(param);
801 if (!hc) {
802 DMWARN("device doesn't appear to be in the dev hash table.");
803 up_write(&_hash_lock);
804 return -ENXIO;
805 }
806
807 md = hc->md;
808
809 new_map = hc->new_map;
810 hc->new_map = NULL;
811 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
812
813 up_write(&_hash_lock);
814
815 /* Do we need to load a new map ? */
816 if (new_map) {
817 /* Suspend if it isn't already suspended */
818 if (param->flags & DM_SKIP_LOCKFS_FLAG)
819 suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
820 if (param->flags & DM_NOFLUSH_FLAG)
821 suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
822 if (!dm_suspended(md))
823 dm_suspend(md, suspend_flags);
824
825 r = dm_swap_table(md, new_map);
826 if (r) {
827 dm_put(md);
828 dm_table_put(new_map);
829 return r;
830 }
831
832 if (dm_table_get_mode(new_map) & FMODE_WRITE)
833 set_disk_ro(dm_disk(md), 0);
834 else
835 set_disk_ro(dm_disk(md), 1);
836
837 dm_table_put(new_map);
838 }
839
840 if (dm_suspended(md))
841 r = dm_resume(md);
842
843 if (!r)
844 r = __dev_status(md, param);
845
846 dm_put(md);
847 return r;
848 }
849
850 /*
851 * Set or unset the suspension state of a device.
852 * If the device already is in the requested state we just return its status.
853 */
854 static int dev_suspend(struct dm_ioctl *param, size_t param_size)
855 {
856 if (param->flags & DM_SUSPEND_FLAG)
857 return do_suspend(param);
858
859 return do_resume(param);
860 }
861
862 /*
863 * Copies device info back to user space, used by
864 * the create and info ioctls.
865 */
866 static int dev_status(struct dm_ioctl *param, size_t param_size)
867 {
868 int r;
869 struct mapped_device *md;
870
871 md = find_device(param);
872 if (!md)
873 return -ENXIO;
874
875 r = __dev_status(md, param);
876 dm_put(md);
877 return r;
878 }
879
880 /*
881 * Build up the status struct for each target
882 */
883 static void retrieve_status(struct dm_table *table,
884 struct dm_ioctl *param, size_t param_size)
885 {
886 unsigned int i, num_targets;
887 struct dm_target_spec *spec;
888 char *outbuf, *outptr;
889 status_type_t type;
890 size_t remaining, len, used = 0;
891
892 outptr = outbuf = get_result_buffer(param, param_size, &len);
893
894 if (param->flags & DM_STATUS_TABLE_FLAG)
895 type = STATUSTYPE_TABLE;
896 else
897 type = STATUSTYPE_INFO;
898
899 /* Get all the target info */
900 num_targets = dm_table_get_num_targets(table);
901 for (i = 0; i < num_targets; i++) {
902 struct dm_target *ti = dm_table_get_target(table, i);
903
904 remaining = len - (outptr - outbuf);
905 if (remaining <= sizeof(struct dm_target_spec)) {
906 param->flags |= DM_BUFFER_FULL_FLAG;
907 break;
908 }
909
910 spec = (struct dm_target_spec *) outptr;
911
912 spec->status = 0;
913 spec->sector_start = ti->begin;
914 spec->length = ti->len;
915 strncpy(spec->target_type, ti->type->name,
916 sizeof(spec->target_type));
917
918 outptr += sizeof(struct dm_target_spec);
919 remaining = len - (outptr - outbuf);
920 if (remaining <= 0) {
921 param->flags |= DM_BUFFER_FULL_FLAG;
922 break;
923 }
924
925 /* Get the status/table string from the target driver */
926 if (ti->type->status) {
927 if (ti->type->status(ti, type, outptr, remaining)) {
928 param->flags |= DM_BUFFER_FULL_FLAG;
929 break;
930 }
931 } else
932 outptr[0] = '\0';
933
934 outptr += strlen(outptr) + 1;
935 used = param->data_start + (outptr - outbuf);
936
937 outptr = align_ptr(outptr);
938 spec->next = outptr - outbuf;
939 }
940
941 if (used)
942 param->data_size = used;
943
944 param->target_count = num_targets;
945 }
946
947 /*
948 * Wait for a device to report an event
949 */
950 static int dev_wait(struct dm_ioctl *param, size_t param_size)
951 {
952 int r;
953 struct mapped_device *md;
954 struct dm_table *table;
955
956 md = find_device(param);
957 if (!md)
958 return -ENXIO;
959
960 /*
961 * Wait for a notification event
962 */
963 if (dm_wait_event(md, param->event_nr)) {
964 r = -ERESTARTSYS;
965 goto out;
966 }
967
968 /*
969 * The userland program is going to want to know what
970 * changed to trigger the event, so we may as well tell
971 * him and save an ioctl.
972 */
973 r = __dev_status(md, param);
974 if (r)
975 goto out;
976
977 table = dm_get_table(md);
978 if (table) {
979 retrieve_status(table, param, param_size);
980 dm_table_put(table);
981 }
982
983 out:
984 dm_put(md);
985 return r;
986 }
987
988 static inline int get_mode(struct dm_ioctl *param)
989 {
990 int mode = FMODE_READ | FMODE_WRITE;
991
992 if (param->flags & DM_READONLY_FLAG)
993 mode = FMODE_READ;
994
995 return mode;
996 }
997
998 static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
999 struct dm_target_spec **spec, char **target_params)
1000 {
1001 *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
1002 *target_params = (char *) (*spec + 1);
1003
1004 if (*spec < (last + 1))
1005 return -EINVAL;
1006
1007 return invalid_str(*target_params, end);
1008 }
1009
1010 static int populate_table(struct dm_table *table,
1011 struct dm_ioctl *param, size_t param_size)
1012 {
1013 int r;
1014 unsigned int i = 0;
1015 struct dm_target_spec *spec = (struct dm_target_spec *) param;
1016 uint32_t next = param->data_start;
1017 void *end = (void *) param + param_size;
1018 char *target_params;
1019
1020 if (!param->target_count) {
1021 DMWARN("populate_table: no targets specified");
1022 return -EINVAL;
1023 }
1024
1025 for (i = 0; i < param->target_count; i++) {
1026
1027 r = next_target(spec, next, end, &spec, &target_params);
1028 if (r) {
1029 DMWARN("unable to find target");
1030 return r;
1031 }
1032
1033 r = dm_table_add_target(table, spec->target_type,
1034 (sector_t) spec->sector_start,
1035 (sector_t) spec->length,
1036 target_params);
1037 if (r) {
1038 DMWARN("error adding target to table");
1039 return r;
1040 }
1041
1042 next = spec->next;
1043 }
1044
1045 return dm_table_complete(table);
1046 }
1047
1048 static int table_load(struct dm_ioctl *param, size_t param_size)
1049 {
1050 int r;
1051 struct hash_cell *hc;
1052 struct dm_table *t;
1053 struct mapped_device *md;
1054
1055 md = find_device(param);
1056 if (!md)
1057 return -ENXIO;
1058
1059 r = dm_table_create(&t, get_mode(param), param->target_count, md);
1060 if (r)
1061 goto out;
1062
1063 r = populate_table(t, param, param_size);
1064 if (r) {
1065 dm_table_put(t);
1066 goto out;
1067 }
1068
1069 down_write(&_hash_lock);
1070 hc = dm_get_mdptr(md);
1071 if (!hc || hc->md != md) {
1072 DMWARN("device has been removed from the dev hash table.");
1073 dm_table_put(t);
1074 up_write(&_hash_lock);
1075 r = -ENXIO;
1076 goto out;
1077 }
1078
1079 if (hc->new_map)
1080 dm_table_put(hc->new_map);
1081 hc->new_map = t;
1082 up_write(&_hash_lock);
1083
1084 param->flags |= DM_INACTIVE_PRESENT_FLAG;
1085 r = __dev_status(md, param);
1086
1087 out:
1088 dm_put(md);
1089
1090 return r;
1091 }
1092
1093 static int table_clear(struct dm_ioctl *param, size_t param_size)
1094 {
1095 int r;
1096 struct hash_cell *hc;
1097 struct mapped_device *md;
1098
1099 down_write(&_hash_lock);
1100
1101 hc = __find_device_hash_cell(param);
1102 if (!hc) {
1103 DMWARN("device doesn't appear to be in the dev hash table.");
1104 up_write(&_hash_lock);
1105 return -ENXIO;
1106 }
1107
1108 if (hc->new_map) {
1109 dm_table_put(hc->new_map);
1110 hc->new_map = NULL;
1111 }
1112
1113 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
1114
1115 r = __dev_status(hc->md, param);
1116 md = hc->md;
1117 up_write(&_hash_lock);
1118 dm_put(md);
1119 return r;
1120 }
1121
1122 /*
1123 * Retrieves a list of devices used by a particular dm device.
1124 */
1125 static void retrieve_deps(struct dm_table *table,
1126 struct dm_ioctl *param, size_t param_size)
1127 {
1128 unsigned int count = 0;
1129 struct list_head *tmp;
1130 size_t len, needed;
1131 struct dm_dev *dd;
1132 struct dm_target_deps *deps;
1133
1134 deps = get_result_buffer(param, param_size, &len);
1135
1136 /*
1137 * Count the devices.
1138 */
1139 list_for_each (tmp, dm_table_get_devices(table))
1140 count++;
1141
1142 /*
1143 * Check we have enough space.
1144 */
1145 needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
1146 if (len < needed) {
1147 param->flags |= DM_BUFFER_FULL_FLAG;
1148 return;
1149 }
1150
1151 /*
1152 * Fill in the devices.
1153 */
1154 deps->count = count;
1155 count = 0;
1156 list_for_each_entry (dd, dm_table_get_devices(table), list)
1157 deps->dev[count++] = huge_encode_dev(dd->bdev->bd_dev);
1158
1159 param->data_size = param->data_start + needed;
1160 }
1161
1162 static int table_deps(struct dm_ioctl *param, size_t param_size)
1163 {
1164 int r = 0;
1165 struct mapped_device *md;
1166 struct dm_table *table;
1167
1168 md = find_device(param);
1169 if (!md)
1170 return -ENXIO;
1171
1172 r = __dev_status(md, param);
1173 if (r)
1174 goto out;
1175
1176 table = dm_get_table(md);
1177 if (table) {
1178 retrieve_deps(table, param, param_size);
1179 dm_table_put(table);
1180 }
1181
1182 out:
1183 dm_put(md);
1184 return r;
1185 }
1186
1187 /*
1188 * Return the status of a device as a text string for each
1189 * target.
1190 */
1191 static int table_status(struct dm_ioctl *param, size_t param_size)
1192 {
1193 int r;
1194 struct mapped_device *md;
1195 struct dm_table *table;
1196
1197 md = find_device(param);
1198 if (!md)
1199 return -ENXIO;
1200
1201 r = __dev_status(md, param);
1202 if (r)
1203 goto out;
1204
1205 table = dm_get_table(md);
1206 if (table) {
1207 retrieve_status(table, param, param_size);
1208 dm_table_put(table);
1209 }
1210
1211 out:
1212 dm_put(md);
1213 return r;
1214 }
1215
1216 /*
1217 * Pass a message to the target that's at the supplied device offset.
1218 */
1219 static int target_message(struct dm_ioctl *param, size_t param_size)
1220 {
1221 int r, argc;
1222 char **argv;
1223 struct mapped_device *md;
1224 struct dm_table *table;
1225 struct dm_target *ti;
1226 struct dm_target_msg *tmsg = (void *) param + param->data_start;
1227
1228 md = find_device(param);
1229 if (!md)
1230 return -ENXIO;
1231
1232 r = __dev_status(md, param);
1233 if (r)
1234 goto out;
1235
1236 if (tmsg < (struct dm_target_msg *) (param + 1) ||
1237 invalid_str(tmsg->message, (void *) param + param_size)) {
1238 DMWARN("Invalid target message parameters.");
1239 r = -EINVAL;
1240 goto out;
1241 }
1242
1243 r = dm_split_args(&argc, &argv, tmsg->message);
1244 if (r) {
1245 DMWARN("Failed to split target message parameters");
1246 goto out;
1247 }
1248
1249 table = dm_get_table(md);
1250 if (!table)
1251 goto out_argv;
1252
1253 if (tmsg->sector >= dm_table_get_size(table)) {
1254 DMWARN("Target message sector outside device.");
1255 r = -EINVAL;
1256 goto out_table;
1257 }
1258
1259 ti = dm_table_find_target(table, tmsg->sector);
1260 if (ti->type->message)
1261 r = ti->type->message(ti, argc, argv);
1262 else {
1263 DMWARN("Target type does not support messages");
1264 r = -EINVAL;
1265 }
1266
1267 out_table:
1268 dm_table_put(table);
1269 out_argv:
1270 kfree(argv);
1271 out:
1272 param->data_size = 0;
1273 dm_put(md);
1274 return r;
1275 }
1276
1277 /*-----------------------------------------------------------------
1278 * Implementation of open/close/ioctl on the special char
1279 * device.
1280 *---------------------------------------------------------------*/
1281 static ioctl_fn lookup_ioctl(unsigned int cmd)
1282 {
1283 static struct {
1284 int cmd;
1285 ioctl_fn fn;
1286 } _ioctls[] = {
1287 {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
1288 {DM_REMOVE_ALL_CMD, remove_all},
1289 {DM_LIST_DEVICES_CMD, list_devices},
1290
1291 {DM_DEV_CREATE_CMD, dev_create},
1292 {DM_DEV_REMOVE_CMD, dev_remove},
1293 {DM_DEV_RENAME_CMD, dev_rename},
1294 {DM_DEV_SUSPEND_CMD, dev_suspend},
1295 {DM_DEV_STATUS_CMD, dev_status},
1296 {DM_DEV_WAIT_CMD, dev_wait},
1297
1298 {DM_TABLE_LOAD_CMD, table_load},
1299 {DM_TABLE_CLEAR_CMD, table_clear},
1300 {DM_TABLE_DEPS_CMD, table_deps},
1301 {DM_TABLE_STATUS_CMD, table_status},
1302
1303 {DM_LIST_VERSIONS_CMD, list_versions},
1304
1305 {DM_TARGET_MSG_CMD, target_message},
1306 {DM_DEV_SET_GEOMETRY_CMD, dev_set_geometry}
1307 };
1308
1309 return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
1310 }
1311
1312 /*
1313 * As well as checking the version compatibility this always
1314 * copies the kernel interface version out.
1315 */
1316 static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
1317 {
1318 uint32_t version[3];
1319 int r = 0;
1320
1321 if (copy_from_user(version, user->version, sizeof(version)))
1322 return -EFAULT;
1323
1324 if ((DM_VERSION_MAJOR != version[0]) ||
1325 (DM_VERSION_MINOR < version[1])) {
1326 DMWARN("ioctl interface mismatch: "
1327 "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
1328 DM_VERSION_MAJOR, DM_VERSION_MINOR,
1329 DM_VERSION_PATCHLEVEL,
1330 version[0], version[1], version[2], cmd);
1331 r = -EINVAL;
1332 }
1333
1334 /*
1335 * Fill in the kernel version.
1336 */
1337 version[0] = DM_VERSION_MAJOR;
1338 version[1] = DM_VERSION_MINOR;
1339 version[2] = DM_VERSION_PATCHLEVEL;
1340 if (copy_to_user(user->version, version, sizeof(version)))
1341 return -EFAULT;
1342
1343 return r;
1344 }
1345
1346 static void free_params(struct dm_ioctl *param)
1347 {
1348 vfree(param);
1349 }
1350
1351 static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
1352 {
1353 struct dm_ioctl tmp, *dmi;
1354
1355 if (copy_from_user(&tmp, user, sizeof(tmp)))
1356 return -EFAULT;
1357
1358 if (tmp.data_size < sizeof(tmp))
1359 return -EINVAL;
1360
1361 dmi = (struct dm_ioctl *) vmalloc(tmp.data_size);
1362 if (!dmi)
1363 return -ENOMEM;
1364
1365 if (copy_from_user(dmi, user, tmp.data_size)) {
1366 vfree(dmi);
1367 return -EFAULT;
1368 }
1369
1370 *param = dmi;
1371 return 0;
1372 }
1373
1374 static int validate_params(uint cmd, struct dm_ioctl *param)
1375 {
1376 /* Always clear this flag */
1377 param->flags &= ~DM_BUFFER_FULL_FLAG;
1378
1379 /* Ignores parameters */
1380 if (cmd == DM_REMOVE_ALL_CMD ||
1381 cmd == DM_LIST_DEVICES_CMD ||
1382 cmd == DM_LIST_VERSIONS_CMD)
1383 return 0;
1384
1385 if ((cmd == DM_DEV_CREATE_CMD)) {
1386 if (!*param->name) {
1387 DMWARN("name not supplied when creating device");
1388 return -EINVAL;
1389 }
1390 } else if ((*param->uuid && *param->name)) {
1391 DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
1392 return -EINVAL;
1393 }
1394
1395 /* Ensure strings are terminated */
1396 param->name[DM_NAME_LEN - 1] = '\0';
1397 param->uuid[DM_UUID_LEN - 1] = '\0';
1398
1399 return 0;
1400 }
1401
1402 static int ctl_ioctl(struct inode *inode, struct file *file,
1403 uint command, ulong u)
1404 {
1405 int r = 0;
1406 unsigned int cmd;
1407 struct dm_ioctl *param;
1408 struct dm_ioctl __user *user = (struct dm_ioctl __user *) u;
1409 ioctl_fn fn = NULL;
1410 size_t param_size;
1411
1412 /* only root can play with this */
1413 if (!capable(CAP_SYS_ADMIN))
1414 return -EACCES;
1415
1416 if (_IOC_TYPE(command) != DM_IOCTL)
1417 return -ENOTTY;
1418
1419 cmd = _IOC_NR(command);
1420
1421 /*
1422 * Check the interface version passed in. This also
1423 * writes out the kernel's interface version.
1424 */
1425 r = check_version(cmd, user);
1426 if (r)
1427 return r;
1428
1429 /*
1430 * Nothing more to do for the version command.
1431 */
1432 if (cmd == DM_VERSION_CMD)
1433 return 0;
1434
1435 fn = lookup_ioctl(cmd);
1436 if (!fn) {
1437 DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
1438 return -ENOTTY;
1439 }
1440
1441 /*
1442 * Trying to avoid low memory issues when a device is
1443 * suspended.
1444 */
1445 current->flags |= PF_MEMALLOC;
1446
1447 /*
1448 * Copy the parameters into kernel space.
1449 */
1450 r = copy_params(user, &param);
1451
1452 current->flags &= ~PF_MEMALLOC;
1453
1454 if (r)
1455 return r;
1456
1457 r = validate_params(cmd, param);
1458 if (r)
1459 goto out;
1460
1461 param_size = param->data_size;
1462 param->data_size = sizeof(*param);
1463 r = fn(param, param_size);
1464
1465 /*
1466 * Copy the results back to userland.
1467 */
1468 if (!r && copy_to_user(user, param, param->data_size))
1469 r = -EFAULT;
1470
1471 out:
1472 free_params(param);
1473 return r;
1474 }
1475
1476 static const struct file_operations _ctl_fops = {
1477 .ioctl = ctl_ioctl,
1478 .owner = THIS_MODULE,
1479 };
1480
1481 static struct miscdevice _dm_misc = {
1482 .minor = MISC_DYNAMIC_MINOR,
1483 .name = DM_NAME,
1484 .fops = &_ctl_fops
1485 };
1486
1487 /*
1488 * Create misc character device and link to DM_DIR/control.
1489 */
1490 int __init dm_interface_init(void)
1491 {
1492 int r;
1493
1494 r = dm_hash_init();
1495 if (r)
1496 return r;
1497
1498 r = misc_register(&_dm_misc);
1499 if (r) {
1500 DMERR("misc_register failed for control device");
1501 dm_hash_exit();
1502 return r;
1503 }
1504
1505 DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
1506 DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
1507 DM_DRIVER_EMAIL);
1508 return 0;
1509 }
1510
1511 void dm_interface_exit(void)
1512 {
1513 if (misc_deregister(&_dm_misc) < 0)
1514 DMERR("misc_deregister failed for control device");
1515
1516 dm_hash_exit();
1517 }
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