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[PATCH] dquot: add proper locking when using current->signal->tty
[usb.git] / drivers / md / dm-ioctl.c
blobd13bb15a8a02981f69706048d32bfc64b83b73c1
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 mdptr = dm_get_mdptr(md);
611
612 return mdptr;
613 }
614
615 static struct mapped_device *find_device(struct dm_ioctl *param)
616 {
617 struct hash_cell *hc;
618 struct mapped_device *md = NULL;
619
620 down_read(&_hash_lock);
621 hc = __find_device_hash_cell(param);
622 if (hc) {
623 md = hc->md;
624
625 /*
626 * Sneakily write in both the name and the uuid
627 * while we have the cell.
628 */
629 strncpy(param->name, hc->name, sizeof(param->name));
630 if (hc->uuid)
631 strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
632 else
633 param->uuid[0] = '\0';
634
635 if (hc->new_map)
636 param->flags |= DM_INACTIVE_PRESENT_FLAG;
637 else
638 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
639 }
640 up_read(&_hash_lock);
641
642 return md;
643 }
644
645 static int dev_remove(struct dm_ioctl *param, size_t param_size)
646 {
647 struct hash_cell *hc;
648 struct mapped_device *md;
649 int r;
650
651 down_write(&_hash_lock);
652 hc = __find_device_hash_cell(param);
653
654 if (!hc) {
655 DMWARN("device doesn't appear to be in the dev hash table.");
656 up_write(&_hash_lock);
657 return -ENXIO;
658 }
659
660 md = hc->md;
661
662 /*
663 * Ensure the device is not open and nothing further can open it.
664 */
665 r = dm_lock_for_deletion(md);
666 if (r) {
667 DMWARN("unable to remove open device %s", hc->name);
668 up_write(&_hash_lock);
669 dm_put(md);
670 return r;
671 }
672
673 __hash_remove(hc);
674 up_write(&_hash_lock);
675 dm_put(md);
676 param->data_size = 0;
677 return 0;
678 }
679
680 /*
681 * Check a string doesn't overrun the chunk of
682 * memory we copied from userland.
683 */
684 static int invalid_str(char *str, void *end)
685 {
686 while ((void *) str < end)
687 if (!*str++)
688 return 0;
689
690 return -EINVAL;
691 }
692
693 static int dev_rename(struct dm_ioctl *param, size_t param_size)
694 {
695 int r;
696 char *new_name = (char *) param + param->data_start;
697
698 if (new_name < (char *) (param + 1) ||
699 invalid_str(new_name, (void *) param + param_size)) {
700 DMWARN("Invalid new logical volume name supplied.");
701 return -EINVAL;
702 }
703
704 r = check_name(new_name);
705 if (r)
706 return r;
707
708 param->data_size = 0;
709 return dm_hash_rename(param->name, new_name);
710 }
711
712 static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
713 {
714 int r = -EINVAL, x;
715 struct mapped_device *md;
716 struct hd_geometry geometry;
717 unsigned long indata[4];
718 char *geostr = (char *) param + param->data_start;
719
720 md = find_device(param);
721 if (!md)
722 return -ENXIO;
723
724 if (geostr < (char *) (param + 1) ||
725 invalid_str(geostr, (void *) param + param_size)) {
726 DMWARN("Invalid geometry supplied.");
727 goto out;
728 }
729
730 x = sscanf(geostr, "%lu %lu %lu %lu", indata,
731 indata + 1, indata + 2, indata + 3);
732
733 if (x != 4) {
734 DMWARN("Unable to interpret geometry settings.");
735 goto out;
736 }
737
738 if (indata[0] > 65535 || indata[1] > 255 ||
739 indata[2] > 255 || indata[3] > ULONG_MAX) {
740 DMWARN("Geometry exceeds range limits.");
741 goto out;
742 }
743
744 geometry.cylinders = indata[0];
745 geometry.heads = indata[1];
746 geometry.sectors = indata[2];
747 geometry.start = indata[3];
748
749 r = dm_set_geometry(md, &geometry);
750 if (!r)
751 r = __dev_status(md, param);
752
753 param->data_size = 0;
754
755 out:
756 dm_put(md);
757 return r;
758 }
759
760 static int do_suspend(struct dm_ioctl *param)
761 {
762 int r = 0;
763 int do_lockfs = 1;
764 struct mapped_device *md;
765
766 md = find_device(param);
767 if (!md)
768 return -ENXIO;
769
770 if (param->flags & DM_SKIP_LOCKFS_FLAG)
771 do_lockfs = 0;
772
773 if (!dm_suspended(md))
774 r = dm_suspend(md, do_lockfs);
775
776 if (!r)
777 r = __dev_status(md, param);
778
779 dm_put(md);
780 return r;
781 }
782
783 static int do_resume(struct dm_ioctl *param)
784 {
785 int r = 0;
786 int do_lockfs = 1;
787 struct hash_cell *hc;
788 struct mapped_device *md;
789 struct dm_table *new_map;
790
791 down_write(&_hash_lock);
792
793 hc = __find_device_hash_cell(param);
794 if (!hc) {
795 DMWARN("device doesn't appear to be in the dev hash table.");
796 up_write(&_hash_lock);
797 return -ENXIO;
798 }
799
800 md = hc->md;
801
802 new_map = hc->new_map;
803 hc->new_map = NULL;
804 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
805
806 up_write(&_hash_lock);
807
808 /* Do we need to load a new map ? */
809 if (new_map) {
810 /* Suspend if it isn't already suspended */
811 if (param->flags & DM_SKIP_LOCKFS_FLAG)
812 do_lockfs = 0;
813 if (!dm_suspended(md))
814 dm_suspend(md, do_lockfs);
815
816 r = dm_swap_table(md, new_map);
817 if (r) {
818 dm_put(md);
819 dm_table_put(new_map);
820 return r;
821 }
822
823 if (dm_table_get_mode(new_map) & FMODE_WRITE)
824 set_disk_ro(dm_disk(md), 0);
825 else
826 set_disk_ro(dm_disk(md), 1);
827
828 dm_table_put(new_map);
829 }
830
831 if (dm_suspended(md))
832 r = dm_resume(md);
833
834 if (!r)
835 r = __dev_status(md, param);
836
837 dm_put(md);
838 return r;
839 }
840
841 /*
842 * Set or unset the suspension state of a device.
843 * If the device already is in the requested state we just return its status.
844 */
845 static int dev_suspend(struct dm_ioctl *param, size_t param_size)
846 {
847 if (param->flags & DM_SUSPEND_FLAG)
848 return do_suspend(param);
849
850 return do_resume(param);
851 }
852
853 /*
854 * Copies device info back to user space, used by
855 * the create and info ioctls.
856 */
857 static int dev_status(struct dm_ioctl *param, size_t param_size)
858 {
859 int r;
860 struct mapped_device *md;
861
862 md = find_device(param);
863 if (!md)
864 return -ENXIO;
865
866 r = __dev_status(md, param);
867 dm_put(md);
868 return r;
869 }
870
871 /*
872 * Build up the status struct for each target
873 */
874 static void retrieve_status(struct dm_table *table,
875 struct dm_ioctl *param, size_t param_size)
876 {
877 unsigned int i, num_targets;
878 struct dm_target_spec *spec;
879 char *outbuf, *outptr;
880 status_type_t type;
881 size_t remaining, len, used = 0;
882
883 outptr = outbuf = get_result_buffer(param, param_size, &len);
884
885 if (param->flags & DM_STATUS_TABLE_FLAG)
886 type = STATUSTYPE_TABLE;
887 else
888 type = STATUSTYPE_INFO;
889
890 /* Get all the target info */
891 num_targets = dm_table_get_num_targets(table);
892 for (i = 0; i < num_targets; i++) {
893 struct dm_target *ti = dm_table_get_target(table, i);
894
895 remaining = len - (outptr - outbuf);
896 if (remaining <= sizeof(struct dm_target_spec)) {
897 param->flags |= DM_BUFFER_FULL_FLAG;
898 break;
899 }
900
901 spec = (struct dm_target_spec *) outptr;
902
903 spec->status = 0;
904 spec->sector_start = ti->begin;
905 spec->length = ti->len;
906 strncpy(spec->target_type, ti->type->name,
907 sizeof(spec->target_type));
908
909 outptr += sizeof(struct dm_target_spec);
910 remaining = len - (outptr - outbuf);
911 if (remaining <= 0) {
912 param->flags |= DM_BUFFER_FULL_FLAG;
913 break;
914 }
915
916 /* Get the status/table string from the target driver */
917 if (ti->type->status) {
918 if (ti->type->status(ti, type, outptr, remaining)) {
919 param->flags |= DM_BUFFER_FULL_FLAG;
920 break;
921 }
922 } else
923 outptr[0] = '\0';
924
925 outptr += strlen(outptr) + 1;
926 used = param->data_start + (outptr - outbuf);
927
928 outptr = align_ptr(outptr);
929 spec->next = outptr - outbuf;
930 }
931
932 if (used)
933 param->data_size = used;
934
935 param->target_count = num_targets;
936 }
937
938 /*
939 * Wait for a device to report an event
940 */
941 static int dev_wait(struct dm_ioctl *param, size_t param_size)
942 {
943 int r;
944 struct mapped_device *md;
945 struct dm_table *table;
946
947 md = find_device(param);
948 if (!md)
949 return -ENXIO;
950
951 /*
952 * Wait for a notification event
953 */
954 if (dm_wait_event(md, param->event_nr)) {
955 r = -ERESTARTSYS;
956 goto out;
957 }
958
959 /*
960 * The userland program is going to want to know what
961 * changed to trigger the event, so we may as well tell
962 * him and save an ioctl.
963 */
964 r = __dev_status(md, param);
965 if (r)
966 goto out;
967
968 table = dm_get_table(md);
969 if (table) {
970 retrieve_status(table, param, param_size);
971 dm_table_put(table);
972 }
973
974 out:
975 dm_put(md);
976 return r;
977 }
978
979 static inline int get_mode(struct dm_ioctl *param)
980 {
981 int mode = FMODE_READ | FMODE_WRITE;
982
983 if (param->flags & DM_READONLY_FLAG)
984 mode = FMODE_READ;
985
986 return mode;
987 }
988
989 static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
990 struct dm_target_spec **spec, char **target_params)
991 {
992 *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
993 *target_params = (char *) (*spec + 1);
994
995 if (*spec < (last + 1))
996 return -EINVAL;
997
998 return invalid_str(*target_params, end);
999 }
1000
1001 static int populate_table(struct dm_table *table,
1002 struct dm_ioctl *param, size_t param_size)
1003 {
1004 int r;
1005 unsigned int i = 0;
1006 struct dm_target_spec *spec = (struct dm_target_spec *) param;
1007 uint32_t next = param->data_start;
1008 void *end = (void *) param + param_size;
1009 char *target_params;
1010
1011 if (!param->target_count) {
1012 DMWARN("populate_table: no targets specified");
1013 return -EINVAL;
1014 }
1015
1016 for (i = 0; i < param->target_count; i++) {
1017
1018 r = next_target(spec, next, end, &spec, &target_params);
1019 if (r) {
1020 DMWARN("unable to find target");
1021 return r;
1022 }
1023
1024 r = dm_table_add_target(table, spec->target_type,
1025 (sector_t) spec->sector_start,
1026 (sector_t) spec->length,
1027 target_params);
1028 if (r) {
1029 DMWARN("error adding target to table");
1030 return r;
1031 }
1032
1033 next = spec->next;
1034 }
1035
1036 return dm_table_complete(table);
1037 }
1038
1039 static int table_load(struct dm_ioctl *param, size_t param_size)
1040 {
1041 int r;
1042 struct hash_cell *hc;
1043 struct dm_table *t;
1044 struct mapped_device *md;
1045
1046 md = find_device(param);
1047 if (!md)
1048 return -ENXIO;
1049
1050 r = dm_table_create(&t, get_mode(param), param->target_count, md);
1051 if (r)
1052 goto out;
1053
1054 r = populate_table(t, param, param_size);
1055 if (r) {
1056 dm_table_put(t);
1057 goto out;
1058 }
1059
1060 down_write(&_hash_lock);
1061 hc = dm_get_mdptr(md);
1062 if (!hc || hc->md != md) {
1063 DMWARN("device has been removed from the dev hash table.");
1064 dm_table_put(t);
1065 up_write(&_hash_lock);
1066 r = -ENXIO;
1067 goto out;
1068 }
1069
1070 if (hc->new_map)
1071 dm_table_put(hc->new_map);
1072 hc->new_map = t;
1073 up_write(&_hash_lock);
1074
1075 param->flags |= DM_INACTIVE_PRESENT_FLAG;
1076 r = __dev_status(md, param);
1077
1078 out:
1079 dm_put(md);
1080
1081 return r;
1082 }
1083
1084 static int table_clear(struct dm_ioctl *param, size_t param_size)
1085 {
1086 int r;
1087 struct hash_cell *hc;
1088 struct mapped_device *md;
1089
1090 down_write(&_hash_lock);
1091
1092 hc = __find_device_hash_cell(param);
1093 if (!hc) {
1094 DMWARN("device doesn't appear to be in the dev hash table.");
1095 up_write(&_hash_lock);
1096 return -ENXIO;
1097 }
1098
1099 if (hc->new_map) {
1100 dm_table_put(hc->new_map);
1101 hc->new_map = NULL;
1102 }
1103
1104 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
1105
1106 r = __dev_status(hc->md, param);
1107 md = hc->md;
1108 up_write(&_hash_lock);
1109 dm_put(md);
1110 return r;
1111 }
1112
1113 /*
1114 * Retrieves a list of devices used by a particular dm device.
1115 */
1116 static void retrieve_deps(struct dm_table *table,
1117 struct dm_ioctl *param, size_t param_size)
1118 {
1119 unsigned int count = 0;
1120 struct list_head *tmp;
1121 size_t len, needed;
1122 struct dm_dev *dd;
1123 struct dm_target_deps *deps;
1124
1125 deps = get_result_buffer(param, param_size, &len);
1126
1127 /*
1128 * Count the devices.
1129 */
1130 list_for_each (tmp, dm_table_get_devices(table))
1131 count++;
1132
1133 /*
1134 * Check we have enough space.
1135 */
1136 needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
1137 if (len < needed) {
1138 param->flags |= DM_BUFFER_FULL_FLAG;
1139 return;
1140 }
1141
1142 /*
1143 * Fill in the devices.
1144 */
1145 deps->count = count;
1146 count = 0;
1147 list_for_each_entry (dd, dm_table_get_devices(table), list)
1148 deps->dev[count++] = huge_encode_dev(dd->bdev->bd_dev);
1149
1150 param->data_size = param->data_start + needed;
1151 }
1152
1153 static int table_deps(struct dm_ioctl *param, size_t param_size)
1154 {
1155 int r = 0;
1156 struct mapped_device *md;
1157 struct dm_table *table;
1158
1159 md = find_device(param);
1160 if (!md)
1161 return -ENXIO;
1162
1163 r = __dev_status(md, param);
1164 if (r)
1165 goto out;
1166
1167 table = dm_get_table(md);
1168 if (table) {
1169 retrieve_deps(table, param, param_size);
1170 dm_table_put(table);
1171 }
1172
1173 out:
1174 dm_put(md);
1175 return r;
1176 }
1177
1178 /*
1179 * Return the status of a device as a text string for each
1180 * target.
1181 */
1182 static int table_status(struct dm_ioctl *param, size_t param_size)
1183 {
1184 int r;
1185 struct mapped_device *md;
1186 struct dm_table *table;
1187
1188 md = find_device(param);
1189 if (!md)
1190 return -ENXIO;
1191
1192 r = __dev_status(md, param);
1193 if (r)
1194 goto out;
1195
1196 table = dm_get_table(md);
1197 if (table) {
1198 retrieve_status(table, param, param_size);
1199 dm_table_put(table);
1200 }
1201
1202 out:
1203 dm_put(md);
1204 return r;
1205 }
1206
1207 /*
1208 * Pass a message to the target that's at the supplied device offset.
1209 */
1210 static int target_message(struct dm_ioctl *param, size_t param_size)
1211 {
1212 int r, argc;
1213 char **argv;
1214 struct mapped_device *md;
1215 struct dm_table *table;
1216 struct dm_target *ti;
1217 struct dm_target_msg *tmsg = (void *) param + param->data_start;
1218
1219 md = find_device(param);
1220 if (!md)
1221 return -ENXIO;
1222
1223 r = __dev_status(md, param);
1224 if (r)
1225 goto out;
1226
1227 if (tmsg < (struct dm_target_msg *) (param + 1) ||
1228 invalid_str(tmsg->message, (void *) param + param_size)) {
1229 DMWARN("Invalid target message parameters.");
1230 r = -EINVAL;
1231 goto out;
1232 }
1233
1234 r = dm_split_args(&argc, &argv, tmsg->message);
1235 if (r) {
1236 DMWARN("Failed to split target message parameters");
1237 goto out;
1238 }
1239
1240 table = dm_get_table(md);
1241 if (!table)
1242 goto out_argv;
1243
1244 if (tmsg->sector >= dm_table_get_size(table)) {
1245 DMWARN("Target message sector outside device.");
1246 r = -EINVAL;
1247 goto out_table;
1248 }
1249
1250 ti = dm_table_find_target(table, tmsg->sector);
1251 if (ti->type->message)
1252 r = ti->type->message(ti, argc, argv);
1253 else {
1254 DMWARN("Target type does not support messages");
1255 r = -EINVAL;
1256 }
1257
1258 out_table:
1259 dm_table_put(table);
1260 out_argv:
1261 kfree(argv);
1262 out:
1263 param->data_size = 0;
1264 dm_put(md);
1265 return r;
1266 }
1267
1268 /*-----------------------------------------------------------------
1269 * Implementation of open/close/ioctl on the special char
1270 * device.
1271 *---------------------------------------------------------------*/
1272 static ioctl_fn lookup_ioctl(unsigned int cmd)
1273 {
1274 static struct {
1275 int cmd;
1276 ioctl_fn fn;
1277 } _ioctls[] = {
1278 {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
1279 {DM_REMOVE_ALL_CMD, remove_all},
1280 {DM_LIST_DEVICES_CMD, list_devices},
1281
1282 {DM_DEV_CREATE_CMD, dev_create},
1283 {DM_DEV_REMOVE_CMD, dev_remove},
1284 {DM_DEV_RENAME_CMD, dev_rename},
1285 {DM_DEV_SUSPEND_CMD, dev_suspend},
1286 {DM_DEV_STATUS_CMD, dev_status},
1287 {DM_DEV_WAIT_CMD, dev_wait},
1288
1289 {DM_TABLE_LOAD_CMD, table_load},
1290 {DM_TABLE_CLEAR_CMD, table_clear},
1291 {DM_TABLE_DEPS_CMD, table_deps},
1292 {DM_TABLE_STATUS_CMD, table_status},
1293
1294 {DM_LIST_VERSIONS_CMD, list_versions},
1295
1296 {DM_TARGET_MSG_CMD, target_message},
1297 {DM_DEV_SET_GEOMETRY_CMD, dev_set_geometry}
1298 };
1299
1300 return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
1301 }
1302
1303 /*
1304 * As well as checking the version compatibility this always
1305 * copies the kernel interface version out.
1306 */
1307 static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
1308 {
1309 uint32_t version[3];
1310 int r = 0;
1311
1312 if (copy_from_user(version, user->version, sizeof(version)))
1313 return -EFAULT;
1314
1315 if ((DM_VERSION_MAJOR != version[0]) ||
1316 (DM_VERSION_MINOR < version[1])) {
1317 DMWARN("ioctl interface mismatch: "
1318 "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
1319 DM_VERSION_MAJOR, DM_VERSION_MINOR,
1320 DM_VERSION_PATCHLEVEL,
1321 version[0], version[1], version[2], cmd);
1322 r = -EINVAL;
1323 }
1324
1325 /*
1326 * Fill in the kernel version.
1327 */
1328 version[0] = DM_VERSION_MAJOR;
1329 version[1] = DM_VERSION_MINOR;
1330 version[2] = DM_VERSION_PATCHLEVEL;
1331 if (copy_to_user(user->version, version, sizeof(version)))
1332 return -EFAULT;
1333
1334 return r;
1335 }
1336
1337 static void free_params(struct dm_ioctl *param)
1338 {
1339 vfree(param);
1340 }
1341
1342 static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
1343 {
1344 struct dm_ioctl tmp, *dmi;
1345
1346 if (copy_from_user(&tmp, user, sizeof(tmp)))
1347 return -EFAULT;
1348
1349 if (tmp.data_size < sizeof(tmp))
1350 return -EINVAL;
1351
1352 dmi = (struct dm_ioctl *) vmalloc(tmp.data_size);
1353 if (!dmi)
1354 return -ENOMEM;
1355
1356 if (copy_from_user(dmi, user, tmp.data_size)) {
1357 vfree(dmi);
1358 return -EFAULT;
1359 }
1360
1361 *param = dmi;
1362 return 0;
1363 }
1364
1365 static int validate_params(uint cmd, struct dm_ioctl *param)
1366 {
1367 /* Always clear this flag */
1368 param->flags &= ~DM_BUFFER_FULL_FLAG;
1369
1370 /* Ignores parameters */
1371 if (cmd == DM_REMOVE_ALL_CMD ||
1372 cmd == DM_LIST_DEVICES_CMD ||
1373 cmd == DM_LIST_VERSIONS_CMD)
1374 return 0;
1375
1376 if ((cmd == DM_DEV_CREATE_CMD)) {
1377 if (!*param->name) {
1378 DMWARN("name not supplied when creating device");
1379 return -EINVAL;
1380 }
1381 } else if ((*param->uuid && *param->name)) {
1382 DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
1383 return -EINVAL;
1384 }
1385
1386 /* Ensure strings are terminated */
1387 param->name[DM_NAME_LEN - 1] = '\0';
1388 param->uuid[DM_UUID_LEN - 1] = '\0';
1389
1390 return 0;
1391 }
1392
1393 static int ctl_ioctl(struct inode *inode, struct file *file,
1394 uint command, ulong u)
1395 {
1396 int r = 0;
1397 unsigned int cmd;
1398 struct dm_ioctl *param;
1399 struct dm_ioctl __user *user = (struct dm_ioctl __user *) u;
1400 ioctl_fn fn = NULL;
1401 size_t param_size;
1402
1403 /* only root can play with this */
1404 if (!capable(CAP_SYS_ADMIN))
1405 return -EACCES;
1406
1407 if (_IOC_TYPE(command) != DM_IOCTL)
1408 return -ENOTTY;
1409
1410 cmd = _IOC_NR(command);
1411
1412 /*
1413 * Check the interface version passed in. This also
1414 * writes out the kernel's interface version.
1415 */
1416 r = check_version(cmd, user);
1417 if (r)
1418 return r;
1419
1420 /*
1421 * Nothing more to do for the version command.
1422 */
1423 if (cmd == DM_VERSION_CMD)
1424 return 0;
1425
1426 fn = lookup_ioctl(cmd);
1427 if (!fn) {
1428 DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
1429 return -ENOTTY;
1430 }
1431
1432 /*
1433 * Trying to avoid low memory issues when a device is
1434 * suspended.
1435 */
1436 current->flags |= PF_MEMALLOC;
1437
1438 /*
1439 * Copy the parameters into kernel space.
1440 */
1441 r = copy_params(user, &param);
1442
1443 current->flags &= ~PF_MEMALLOC;
1444
1445 if (r)
1446 return r;
1447
1448 r = validate_params(cmd, param);
1449 if (r)
1450 goto out;
1451
1452 param_size = param->data_size;
1453 param->data_size = sizeof(*param);
1454 r = fn(param, param_size);
1455
1456 /*
1457 * Copy the results back to userland.
1458 */
1459 if (!r && copy_to_user(user, param, param->data_size))
1460 r = -EFAULT;
1461
1462 out:
1463 free_params(param);
1464 return r;
1465 }
1466
1467 static struct file_operations _ctl_fops = {
1468 .ioctl = ctl_ioctl,
1469 .owner = THIS_MODULE,
1470 };
1471
1472 static struct miscdevice _dm_misc = {
1473 .minor = MISC_DYNAMIC_MINOR,
1474 .name = DM_NAME,
1475 .fops = &_ctl_fops
1476 };
1477
1478 /*
1479 * Create misc character device and link to DM_DIR/control.
1480 */
1481 int __init dm_interface_init(void)
1482 {
1483 int r;
1484
1485 r = dm_hash_init();
1486 if (r)
1487 return r;
1488
1489 r = misc_register(&_dm_misc);
1490 if (r) {
1491 DMERR("misc_register failed for control device");
1492 dm_hash_exit();
1493 return r;
1494 }
1495
1496 DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
1497 DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
1498 DM_DRIVER_EMAIL);
1499 return 0;
1500 }
1501
1502 void dm_interface_exit(void)
1503 {
1504 if (misc_deregister(&_dm_misc) < 0)
1505 DMERR("misc_deregister failed for control device");
1506
1507 dm_hash_exit();
1508 }
USB Experimental Work