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mm owner: fix race between swapoff and exit
[linux-2.6/next.git] / drivers / md / dm-ioctl.c
blobb262c0042de3f79394d7ff46c61e36b68da29e48
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 static void init_buckets(struct list_head *buckets)
60 {
61 unsigned int i;
62
63 for (i = 0; i < NUM_BUCKETS; i++)
64 INIT_LIST_HEAD(buckets + i);
65 }
66
67 static int dm_hash_init(void)
68 {
69 init_buckets(_name_buckets);
70 init_buckets(_uuid_buckets);
71 return 0;
72 }
73
74 static void dm_hash_exit(void)
75 {
76 dm_hash_remove_all(0);
77 }
78
79 /*-----------------------------------------------------------------
80 * Hash function:
81 * We're not really concerned with the str hash function being
82 * fast since it's only used by the ioctl interface.
83 *---------------------------------------------------------------*/
84 static unsigned int hash_str(const char *str)
85 {
86 const unsigned int hash_mult = 2654435387U;
87 unsigned int h = 0;
88
89 while (*str)
90 h = (h + (unsigned int) *str++) * hash_mult;
91
92 return h & MASK_BUCKETS;
93 }
94
95 /*-----------------------------------------------------------------
96 * Code for looking up a device by name
97 *---------------------------------------------------------------*/
98 static struct hash_cell *__get_name_cell(const char *str)
99 {
100 struct hash_cell *hc;
101 unsigned int h = hash_str(str);
102
103 list_for_each_entry (hc, _name_buckets + h, name_list)
104 if (!strcmp(hc->name, str)) {
105 dm_get(hc->md);
106 return hc;
107 }
108
109 return NULL;
110 }
111
112 static struct hash_cell *__get_uuid_cell(const char *str)
113 {
114 struct hash_cell *hc;
115 unsigned int h = hash_str(str);
116
117 list_for_each_entry (hc, _uuid_buckets + h, uuid_list)
118 if (!strcmp(hc->uuid, str)) {
119 dm_get(hc->md);
120 return hc;
121 }
122
123 return NULL;
124 }
125
126 /*-----------------------------------------------------------------
127 * Inserting, removing and renaming a device.
128 *---------------------------------------------------------------*/
129 static struct hash_cell *alloc_cell(const char *name, const char *uuid,
130 struct mapped_device *md)
131 {
132 struct hash_cell *hc;
133
134 hc = kmalloc(sizeof(*hc), GFP_KERNEL);
135 if (!hc)
136 return NULL;
137
138 hc->name = kstrdup(name, GFP_KERNEL);
139 if (!hc->name) {
140 kfree(hc);
141 return NULL;
142 }
143
144 if (!uuid)
145 hc->uuid = NULL;
146
147 else {
148 hc->uuid = kstrdup(uuid, GFP_KERNEL);
149 if (!hc->uuid) {
150 kfree(hc->name);
151 kfree(hc);
152 return NULL;
153 }
154 }
155
156 INIT_LIST_HEAD(&hc->name_list);
157 INIT_LIST_HEAD(&hc->uuid_list);
158 hc->md = md;
159 hc->new_map = NULL;
160 return hc;
161 }
162
163 static void free_cell(struct hash_cell *hc)
164 {
165 if (hc) {
166 kfree(hc->name);
167 kfree(hc->uuid);
168 kfree(hc);
169 }
170 }
171
172 /*
173 * The kdev_t and uuid of a device can never change once it is
174 * initially inserted.
175 */
176 static int dm_hash_insert(const char *name, const char *uuid, struct mapped_device *md)
177 {
178 struct hash_cell *cell, *hc;
179
180 /*
181 * Allocate the new cells.
182 */
183 cell = alloc_cell(name, uuid, md);
184 if (!cell)
185 return -ENOMEM;
186
187 /*
188 * Insert the cell into both hash tables.
189 */
190 down_write(&_hash_lock);
191 hc = __get_name_cell(name);
192 if (hc) {
193 dm_put(hc->md);
194 goto bad;
195 }
196
197 list_add(&cell->name_list, _name_buckets + hash_str(name));
198
199 if (uuid) {
200 hc = __get_uuid_cell(uuid);
201 if (hc) {
202 list_del(&cell->name_list);
203 dm_put(hc->md);
204 goto bad;
205 }
206 list_add(&cell->uuid_list, _uuid_buckets + hash_str(uuid));
207 }
208 dm_get(md);
209 dm_set_mdptr(md, cell);
210 up_write(&_hash_lock);
211
212 return 0;
213
214 bad:
215 up_write(&_hash_lock);
216 free_cell(cell);
217 return -EBUSY;
218 }
219
220 static void __hash_remove(struct hash_cell *hc)
221 {
222 struct dm_table *table;
223
224 /* remove from the dev hash */
225 list_del(&hc->uuid_list);
226 list_del(&hc->name_list);
227 dm_set_mdptr(hc->md, NULL);
228
229 table = dm_get_table(hc->md);
230 if (table) {
231 dm_table_event(table);
232 dm_table_put(table);
233 }
234
235 if (hc->new_map)
236 dm_table_put(hc->new_map);
237 dm_put(hc->md);
238 free_cell(hc);
239 }
240
241 static void dm_hash_remove_all(int keep_open_devices)
242 {
243 int i, dev_skipped, dev_removed;
244 struct hash_cell *hc;
245 struct list_head *tmp, *n;
246
247 down_write(&_hash_lock);
248
249 retry:
250 dev_skipped = dev_removed = 0;
251 for (i = 0; i < NUM_BUCKETS; i++) {
252 list_for_each_safe (tmp, n, _name_buckets + i) {
253 hc = list_entry(tmp, struct hash_cell, name_list);
254
255 if (keep_open_devices &&
256 dm_lock_for_deletion(hc->md)) {
257 dev_skipped++;
258 continue;
259 }
260 __hash_remove(hc);
261 dev_removed = 1;
262 }
263 }
264
265 /*
266 * Some mapped devices may be using other mapped devices, so if any
267 * still exist, repeat until we make no further progress.
268 */
269 if (dev_skipped) {
270 if (dev_removed)
271 goto retry;
272
273 DMWARN("remove_all left %d open device(s)", dev_skipped);
274 }
275
276 up_write(&_hash_lock);
277 }
278
279 static int dm_hash_rename(const char *old, const char *new)
280 {
281 char *new_name, *old_name;
282 struct hash_cell *hc;
283 struct dm_table *table;
284
285 /*
286 * duplicate new.
287 */
288 new_name = kstrdup(new, GFP_KERNEL);
289 if (!new_name)
290 return -ENOMEM;
291
292 down_write(&_hash_lock);
293
294 /*
295 * Is new free ?
296 */
297 hc = __get_name_cell(new);
298 if (hc) {
299 DMWARN("asked to rename to an already existing name %s -> %s",
300 old, new);
301 dm_put(hc->md);
302 up_write(&_hash_lock);
303 kfree(new_name);
304 return -EBUSY;
305 }
306
307 /*
308 * Is there such a device as 'old' ?
309 */
310 hc = __get_name_cell(old);
311 if (!hc) {
312 DMWARN("asked to rename a non existent device %s -> %s",
313 old, new);
314 up_write(&_hash_lock);
315 kfree(new_name);
316 return -ENXIO;
317 }
318
319 /*
320 * rename and move the name cell.
321 */
322 list_del(&hc->name_list);
323 old_name = hc->name;
324 hc->name = new_name;
325 list_add(&hc->name_list, _name_buckets + hash_str(new_name));
326
327 /*
328 * Wake up any dm event waiters.
329 */
330 table = dm_get_table(hc->md);
331 if (table) {
332 dm_table_event(table);
333 dm_table_put(table);
334 }
335
336 dm_kobject_uevent(hc->md);
337
338 dm_put(hc->md);
339 up_write(&_hash_lock);
340 kfree(old_name);
341 return 0;
342 }
343
344 /*-----------------------------------------------------------------
345 * Implementation of the ioctl commands
346 *---------------------------------------------------------------*/
347 /*
348 * All the ioctl commands get dispatched to functions with this
349 * prototype.
350 */
351 typedef int (*ioctl_fn)(struct dm_ioctl *param, size_t param_size);
352
353 static int remove_all(struct dm_ioctl *param, size_t param_size)
354 {
355 dm_hash_remove_all(1);
356 param->data_size = 0;
357 return 0;
358 }
359
360 /*
361 * Round up the ptr to an 8-byte boundary.
362 */
363 #define ALIGN_MASK 7
364 static inline void *align_ptr(void *ptr)
365 {
366 return (void *) (((size_t) (ptr + ALIGN_MASK)) & ~ALIGN_MASK);
367 }
368
369 /*
370 * Retrieves the data payload buffer from an already allocated
371 * struct dm_ioctl.
372 */
373 static void *get_result_buffer(struct dm_ioctl *param, size_t param_size,
374 size_t *len)
375 {
376 param->data_start = align_ptr(param + 1) - (void *) param;
377
378 if (param->data_start < param_size)
379 *len = param_size - param->data_start;
380 else
381 *len = 0;
382
383 return ((void *) param) + param->data_start;
384 }
385
386 static int list_devices(struct dm_ioctl *param, size_t param_size)
387 {
388 unsigned int i;
389 struct hash_cell *hc;
390 size_t len, needed = 0;
391 struct gendisk *disk;
392 struct dm_name_list *nl, *old_nl = NULL;
393
394 down_write(&_hash_lock);
395
396 /*
397 * Loop through all the devices working out how much
398 * space we need.
399 */
400 for (i = 0; i < NUM_BUCKETS; i++) {
401 list_for_each_entry (hc, _name_buckets + i, name_list) {
402 needed += sizeof(struct dm_name_list);
403 needed += strlen(hc->name) + 1;
404 needed += ALIGN_MASK;
405 }
406 }
407
408 /*
409 * Grab our output buffer.
410 */
411 nl = get_result_buffer(param, param_size, &len);
412 if (len < needed) {
413 param->flags |= DM_BUFFER_FULL_FLAG;
414 goto out;
415 }
416 param->data_size = param->data_start + needed;
417
418 nl->dev = 0; /* Flags no data */
419
420 /*
421 * Now loop through filling out the names.
422 */
423 for (i = 0; i < NUM_BUCKETS; i++) {
424 list_for_each_entry (hc, _name_buckets + i, name_list) {
425 if (old_nl)
426 old_nl->next = (uint32_t) ((void *) nl -
427 (void *) old_nl);
428 disk = dm_disk(hc->md);
429 nl->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
430 nl->next = 0;
431 strcpy(nl->name, hc->name);
432
433 old_nl = nl;
434 nl = align_ptr(((void *) ++nl) + strlen(hc->name) + 1);
435 }
436 }
437
438 out:
439 up_write(&_hash_lock);
440 return 0;
441 }
442
443 static void list_version_get_needed(struct target_type *tt, void *needed_param)
444 {
445 size_t *needed = needed_param;
446
447 *needed += sizeof(struct dm_target_versions);
448 *needed += strlen(tt->name);
449 *needed += ALIGN_MASK;
450 }
451
452 static void list_version_get_info(struct target_type *tt, void *param)
453 {
454 struct vers_iter *info = param;
455
456 /* Check space - it might have changed since the first iteration */
457 if ((char *)info->vers + sizeof(tt->version) + strlen(tt->name) + 1 >
458 info->end) {
459
460 info->flags = DM_BUFFER_FULL_FLAG;
461 return;
462 }
463
464 if (info->old_vers)
465 info->old_vers->next = (uint32_t) ((void *)info->vers -
466 (void *)info->old_vers);
467 info->vers->version[0] = tt->version[0];
468 info->vers->version[1] = tt->version[1];
469 info->vers->version[2] = tt->version[2];
470 info->vers->next = 0;
471 strcpy(info->vers->name, tt->name);
472
473 info->old_vers = info->vers;
474 info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
475 }
476
477 static int list_versions(struct dm_ioctl *param, size_t param_size)
478 {
479 size_t len, needed = 0;
480 struct dm_target_versions *vers;
481 struct vers_iter iter_info;
482
483 /*
484 * Loop through all the devices working out how much
485 * space we need.
486 */
487 dm_target_iterate(list_version_get_needed, &needed);
488
489 /*
490 * Grab our output buffer.
491 */
492 vers = get_result_buffer(param, param_size, &len);
493 if (len < needed) {
494 param->flags |= DM_BUFFER_FULL_FLAG;
495 goto out;
496 }
497 param->data_size = param->data_start + needed;
498
499 iter_info.param_size = param_size;
500 iter_info.old_vers = NULL;
501 iter_info.vers = vers;
502 iter_info.flags = 0;
503 iter_info.end = (char *)vers+len;
504
505 /*
506 * Now loop through filling out the names & versions.
507 */
508 dm_target_iterate(list_version_get_info, &iter_info);
509 param->flags |= iter_info.flags;
510
511 out:
512 return 0;
513 }
514
515
516
517 static int check_name(const char *name)
518 {
519 if (strchr(name, '/')) {
520 DMWARN("invalid device name");
521 return -EINVAL;
522 }
523
524 return 0;
525 }
526
527 /*
528 * Fills in a dm_ioctl structure, ready for sending back to
529 * userland.
530 */
531 static int __dev_status(struct mapped_device *md, struct dm_ioctl *param)
532 {
533 struct gendisk *disk = dm_disk(md);
534 struct dm_table *table;
535
536 param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
537 DM_ACTIVE_PRESENT_FLAG);
538
539 if (dm_suspended(md))
540 param->flags |= DM_SUSPEND_FLAG;
541
542 param->dev = huge_encode_dev(MKDEV(disk->major, disk->first_minor));
543
544 /*
545 * Yes, this will be out of date by the time it gets back
546 * to userland, but it is still very useful for
547 * debugging.
548 */
549 param->open_count = dm_open_count(md);
550
551 if (disk->policy)
552 param->flags |= DM_READONLY_FLAG;
553
554 param->event_nr = dm_get_event_nr(md);
555
556 table = dm_get_table(md);
557 if (table) {
558 param->flags |= DM_ACTIVE_PRESENT_FLAG;
559 param->target_count = dm_table_get_num_targets(table);
560 dm_table_put(table);
561 } else
562 param->target_count = 0;
563
564 return 0;
565 }
566
567 static int dev_create(struct dm_ioctl *param, size_t param_size)
568 {
569 int r, m = DM_ANY_MINOR;
570 struct mapped_device *md;
571
572 r = check_name(param->name);
573 if (r)
574 return r;
575
576 if (param->flags & DM_PERSISTENT_DEV_FLAG)
577 m = MINOR(huge_decode_dev(param->dev));
578
579 r = dm_create(m, &md);
580 if (r)
581 return r;
582
583 r = dm_hash_insert(param->name, *param->uuid ? param->uuid : NULL, md);
584 if (r) {
585 dm_put(md);
586 return r;
587 }
588
589 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
590
591 r = __dev_status(md, param);
592 dm_put(md);
593
594 return r;
595 }
596
597 /*
598 * Always use UUID for lookups if it's present, otherwise use name or dev.
599 */
600 static struct hash_cell *__find_device_hash_cell(struct dm_ioctl *param)
601 {
602 struct mapped_device *md;
603 void *mdptr = NULL;
604
605 if (*param->uuid)
606 return __get_uuid_cell(param->uuid);
607
608 if (*param->name)
609 return __get_name_cell(param->name);
610
611 md = dm_get_md(huge_decode_dev(param->dev));
612 if (!md)
613 goto out;
614
615 mdptr = dm_get_mdptr(md);
616 if (!mdptr)
617 dm_put(md);
618
619 out:
620 return mdptr;
621 }
622
623 static struct mapped_device *find_device(struct dm_ioctl *param)
624 {
625 struct hash_cell *hc;
626 struct mapped_device *md = NULL;
627
628 down_read(&_hash_lock);
629 hc = __find_device_hash_cell(param);
630 if (hc) {
631 md = hc->md;
632
633 /*
634 * Sneakily write in both the name and the uuid
635 * while we have the cell.
636 */
637 strncpy(param->name, hc->name, sizeof(param->name));
638 if (hc->uuid)
639 strncpy(param->uuid, hc->uuid, sizeof(param->uuid)-1);
640 else
641 param->uuid[0] = '\0';
642
643 if (hc->new_map)
644 param->flags |= DM_INACTIVE_PRESENT_FLAG;
645 else
646 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
647 }
648 up_read(&_hash_lock);
649
650 return md;
651 }
652
653 static int dev_remove(struct dm_ioctl *param, size_t param_size)
654 {
655 struct hash_cell *hc;
656 struct mapped_device *md;
657 int r;
658
659 down_write(&_hash_lock);
660 hc = __find_device_hash_cell(param);
661
662 if (!hc) {
663 DMWARN("device doesn't appear to be in the dev hash table.");
664 up_write(&_hash_lock);
665 return -ENXIO;
666 }
667
668 md = hc->md;
669
670 /*
671 * Ensure the device is not open and nothing further can open it.
672 */
673 r = dm_lock_for_deletion(md);
674 if (r) {
675 DMWARN("unable to remove open device %s", hc->name);
676 up_write(&_hash_lock);
677 dm_put(md);
678 return r;
679 }
680
681 __hash_remove(hc);
682 up_write(&_hash_lock);
683 dm_put(md);
684 param->data_size = 0;
685 return 0;
686 }
687
688 /*
689 * Check a string doesn't overrun the chunk of
690 * memory we copied from userland.
691 */
692 static int invalid_str(char *str, void *end)
693 {
694 while ((void *) str < end)
695 if (!*str++)
696 return 0;
697
698 return -EINVAL;
699 }
700
701 static int dev_rename(struct dm_ioctl *param, size_t param_size)
702 {
703 int r;
704 char *new_name = (char *) param + param->data_start;
705
706 if (new_name < param->data ||
707 invalid_str(new_name, (void *) param + param_size)) {
708 DMWARN("Invalid new logical volume name supplied.");
709 return -EINVAL;
710 }
711
712 r = check_name(new_name);
713 if (r)
714 return r;
715
716 param->data_size = 0;
717 return dm_hash_rename(param->name, new_name);
718 }
719
720 static int dev_set_geometry(struct dm_ioctl *param, size_t param_size)
721 {
722 int r = -EINVAL, x;
723 struct mapped_device *md;
724 struct hd_geometry geometry;
725 unsigned long indata[4];
726 char *geostr = (char *) param + param->data_start;
727
728 md = find_device(param);
729 if (!md)
730 return -ENXIO;
731
732 if (geostr < param->data ||
733 invalid_str(geostr, (void *) param + param_size)) {
734 DMWARN("Invalid geometry supplied.");
735 goto out;
736 }
737
738 x = sscanf(geostr, "%lu %lu %lu %lu", indata,
739 indata + 1, indata + 2, indata + 3);
740
741 if (x != 4) {
742 DMWARN("Unable to interpret geometry settings.");
743 goto out;
744 }
745
746 if (indata[0] > 65535 || indata[1] > 255 ||
747 indata[2] > 255 || indata[3] > ULONG_MAX) {
748 DMWARN("Geometry exceeds range limits.");
749 goto out;
750 }
751
752 geometry.cylinders = indata[0];
753 geometry.heads = indata[1];
754 geometry.sectors = indata[2];
755 geometry.start = indata[3];
756
757 r = dm_set_geometry(md, &geometry);
758 if (!r)
759 r = __dev_status(md, param);
760
761 param->data_size = 0;
762
763 out:
764 dm_put(md);
765 return r;
766 }
767
768 static int do_suspend(struct dm_ioctl *param)
769 {
770 int r = 0;
771 unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
772 struct mapped_device *md;
773
774 md = find_device(param);
775 if (!md)
776 return -ENXIO;
777
778 if (param->flags & DM_SKIP_LOCKFS_FLAG)
779 suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
780 if (param->flags & DM_NOFLUSH_FLAG)
781 suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
782
783 if (!dm_suspended(md))
784 r = dm_suspend(md, suspend_flags);
785
786 if (!r)
787 r = __dev_status(md, param);
788
789 dm_put(md);
790 return r;
791 }
792
793 static int do_resume(struct dm_ioctl *param)
794 {
795 int r = 0;
796 unsigned suspend_flags = DM_SUSPEND_LOCKFS_FLAG;
797 struct hash_cell *hc;
798 struct mapped_device *md;
799 struct dm_table *new_map;
800
801 down_write(&_hash_lock);
802
803 hc = __find_device_hash_cell(param);
804 if (!hc) {
805 DMWARN("device doesn't appear to be in the dev hash table.");
806 up_write(&_hash_lock);
807 return -ENXIO;
808 }
809
810 md = hc->md;
811
812 new_map = hc->new_map;
813 hc->new_map = NULL;
814 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
815
816 up_write(&_hash_lock);
817
818 /* Do we need to load a new map ? */
819 if (new_map) {
820 /* Suspend if it isn't already suspended */
821 if (param->flags & DM_SKIP_LOCKFS_FLAG)
822 suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
823 if (param->flags & DM_NOFLUSH_FLAG)
824 suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG;
825 if (!dm_suspended(md))
826 dm_suspend(md, suspend_flags);
827
828 r = dm_swap_table(md, new_map);
829 if (r) {
830 dm_put(md);
831 dm_table_put(new_map);
832 return r;
833 }
834
835 if (dm_table_get_mode(new_map) & FMODE_WRITE)
836 set_disk_ro(dm_disk(md), 0);
837 else
838 set_disk_ro(dm_disk(md), 1);
839
840 dm_table_put(new_map);
841 }
842
843 if (dm_suspended(md))
844 r = dm_resume(md);
845
846 if (!r)
847 r = __dev_status(md, param);
848
849 dm_put(md);
850 return r;
851 }
852
853 /*
854 * Set or unset the suspension state of a device.
855 * If the device already is in the requested state we just return its status.
856 */
857 static int dev_suspend(struct dm_ioctl *param, size_t param_size)
858 {
859 if (param->flags & DM_SUSPEND_FLAG)
860 return do_suspend(param);
861
862 return do_resume(param);
863 }
864
865 /*
866 * Copies device info back to user space, used by
867 * the create and info ioctls.
868 */
869 static int dev_status(struct dm_ioctl *param, size_t param_size)
870 {
871 int r;
872 struct mapped_device *md;
873
874 md = find_device(param);
875 if (!md)
876 return -ENXIO;
877
878 r = __dev_status(md, param);
879 dm_put(md);
880 return r;
881 }
882
883 /*
884 * Build up the status struct for each target
885 */
886 static void retrieve_status(struct dm_table *table,
887 struct dm_ioctl *param, size_t param_size)
888 {
889 unsigned int i, num_targets;
890 struct dm_target_spec *spec;
891 char *outbuf, *outptr;
892 status_type_t type;
893 size_t remaining, len, used = 0;
894
895 outptr = outbuf = get_result_buffer(param, param_size, &len);
896
897 if (param->flags & DM_STATUS_TABLE_FLAG)
898 type = STATUSTYPE_TABLE;
899 else
900 type = STATUSTYPE_INFO;
901
902 /* Get all the target info */
903 num_targets = dm_table_get_num_targets(table);
904 for (i = 0; i < num_targets; i++) {
905 struct dm_target *ti = dm_table_get_target(table, i);
906
907 remaining = len - (outptr - outbuf);
908 if (remaining <= sizeof(struct dm_target_spec)) {
909 param->flags |= DM_BUFFER_FULL_FLAG;
910 break;
911 }
912
913 spec = (struct dm_target_spec *) outptr;
914
915 spec->status = 0;
916 spec->sector_start = ti->begin;
917 spec->length = ti->len;
918 strncpy(spec->target_type, ti->type->name,
919 sizeof(spec->target_type));
920
921 outptr += sizeof(struct dm_target_spec);
922 remaining = len - (outptr - outbuf);
923 if (remaining <= 0) {
924 param->flags |= DM_BUFFER_FULL_FLAG;
925 break;
926 }
927
928 /* Get the status/table string from the target driver */
929 if (ti->type->status) {
930 if (ti->type->status(ti, type, outptr, remaining)) {
931 param->flags |= DM_BUFFER_FULL_FLAG;
932 break;
933 }
934 } else
935 outptr[0] = '\0';
936
937 outptr += strlen(outptr) + 1;
938 used = param->data_start + (outptr - outbuf);
939
940 outptr = align_ptr(outptr);
941 spec->next = outptr - outbuf;
942 }
943
944 if (used)
945 param->data_size = used;
946
947 param->target_count = num_targets;
948 }
949
950 /*
951 * Wait for a device to report an event
952 */
953 static int dev_wait(struct dm_ioctl *param, size_t param_size)
954 {
955 int r;
956 struct mapped_device *md;
957 struct dm_table *table;
958
959 md = find_device(param);
960 if (!md)
961 return -ENXIO;
962
963 /*
964 * Wait for a notification event
965 */
966 if (dm_wait_event(md, param->event_nr)) {
967 r = -ERESTARTSYS;
968 goto out;
969 }
970
971 /*
972 * The userland program is going to want to know what
973 * changed to trigger the event, so we may as well tell
974 * him and save an ioctl.
975 */
976 r = __dev_status(md, param);
977 if (r)
978 goto out;
979
980 table = dm_get_table(md);
981 if (table) {
982 retrieve_status(table, param, param_size);
983 dm_table_put(table);
984 }
985
986 out:
987 dm_put(md);
988 return r;
989 }
990
991 static inline int get_mode(struct dm_ioctl *param)
992 {
993 int mode = FMODE_READ | FMODE_WRITE;
994
995 if (param->flags & DM_READONLY_FLAG)
996 mode = FMODE_READ;
997
998 return mode;
999 }
1000
1001 static int next_target(struct dm_target_spec *last, uint32_t next, void *end,
1002 struct dm_target_spec **spec, char **target_params)
1003 {
1004 *spec = (struct dm_target_spec *) ((unsigned char *) last + next);
1005 *target_params = (char *) (*spec + 1);
1006
1007 if (*spec < (last + 1))
1008 return -EINVAL;
1009
1010 return invalid_str(*target_params, end);
1011 }
1012
1013 static int populate_table(struct dm_table *table,
1014 struct dm_ioctl *param, size_t param_size)
1015 {
1016 int r;
1017 unsigned int i = 0;
1018 struct dm_target_spec *spec = (struct dm_target_spec *) param;
1019 uint32_t next = param->data_start;
1020 void *end = (void *) param + param_size;
1021 char *target_params;
1022
1023 if (!param->target_count) {
1024 DMWARN("populate_table: no targets specified");
1025 return -EINVAL;
1026 }
1027
1028 for (i = 0; i < param->target_count; i++) {
1029
1030 r = next_target(spec, next, end, &spec, &target_params);
1031 if (r) {
1032 DMWARN("unable to find target");
1033 return r;
1034 }
1035
1036 r = dm_table_add_target(table, spec->target_type,
1037 (sector_t) spec->sector_start,
1038 (sector_t) spec->length,
1039 target_params);
1040 if (r) {
1041 DMWARN("error adding target to table");
1042 return r;
1043 }
1044
1045 next = spec->next;
1046 }
1047
1048 return dm_table_complete(table);
1049 }
1050
1051 static int table_load(struct dm_ioctl *param, size_t param_size)
1052 {
1053 int r;
1054 struct hash_cell *hc;
1055 struct dm_table *t;
1056 struct mapped_device *md;
1057
1058 md = find_device(param);
1059 if (!md)
1060 return -ENXIO;
1061
1062 r = dm_table_create(&t, get_mode(param), param->target_count, md);
1063 if (r)
1064 goto out;
1065
1066 r = populate_table(t, param, param_size);
1067 if (r) {
1068 dm_table_put(t);
1069 goto out;
1070 }
1071
1072 down_write(&_hash_lock);
1073 hc = dm_get_mdptr(md);
1074 if (!hc || hc->md != md) {
1075 DMWARN("device has been removed from the dev hash table.");
1076 dm_table_put(t);
1077 up_write(&_hash_lock);
1078 r = -ENXIO;
1079 goto out;
1080 }
1081
1082 if (hc->new_map)
1083 dm_table_put(hc->new_map);
1084 hc->new_map = t;
1085 up_write(&_hash_lock);
1086
1087 param->flags |= DM_INACTIVE_PRESENT_FLAG;
1088 r = __dev_status(md, param);
1089
1090 out:
1091 dm_put(md);
1092
1093 return r;
1094 }
1095
1096 static int table_clear(struct dm_ioctl *param, size_t param_size)
1097 {
1098 int r;
1099 struct hash_cell *hc;
1100 struct mapped_device *md;
1101
1102 down_write(&_hash_lock);
1103
1104 hc = __find_device_hash_cell(param);
1105 if (!hc) {
1106 DMWARN("device doesn't appear to be in the dev hash table.");
1107 up_write(&_hash_lock);
1108 return -ENXIO;
1109 }
1110
1111 if (hc->new_map) {
1112 dm_table_put(hc->new_map);
1113 hc->new_map = NULL;
1114 }
1115
1116 param->flags &= ~DM_INACTIVE_PRESENT_FLAG;
1117
1118 r = __dev_status(hc->md, param);
1119 md = hc->md;
1120 up_write(&_hash_lock);
1121 dm_put(md);
1122 return r;
1123 }
1124
1125 /*
1126 * Retrieves a list of devices used by a particular dm device.
1127 */
1128 static void retrieve_deps(struct dm_table *table,
1129 struct dm_ioctl *param, size_t param_size)
1130 {
1131 unsigned int count = 0;
1132 struct list_head *tmp;
1133 size_t len, needed;
1134 struct dm_dev *dd;
1135 struct dm_target_deps *deps;
1136
1137 deps = get_result_buffer(param, param_size, &len);
1138
1139 /*
1140 * Count the devices.
1141 */
1142 list_for_each (tmp, dm_table_get_devices(table))
1143 count++;
1144
1145 /*
1146 * Check we have enough space.
1147 */
1148 needed = sizeof(*deps) + (sizeof(*deps->dev) * count);
1149 if (len < needed) {
1150 param->flags |= DM_BUFFER_FULL_FLAG;
1151 return;
1152 }
1153
1154 /*
1155 * Fill in the devices.
1156 */
1157 deps->count = count;
1158 count = 0;
1159 list_for_each_entry (dd, dm_table_get_devices(table), list)
1160 deps->dev[count++] = huge_encode_dev(dd->bdev->bd_dev);
1161
1162 param->data_size = param->data_start + needed;
1163 }
1164
1165 static int table_deps(struct dm_ioctl *param, size_t param_size)
1166 {
1167 int r = 0;
1168 struct mapped_device *md;
1169 struct dm_table *table;
1170
1171 md = find_device(param);
1172 if (!md)
1173 return -ENXIO;
1174
1175 r = __dev_status(md, param);
1176 if (r)
1177 goto out;
1178
1179 table = dm_get_table(md);
1180 if (table) {
1181 retrieve_deps(table, param, param_size);
1182 dm_table_put(table);
1183 }
1184
1185 out:
1186 dm_put(md);
1187 return r;
1188 }
1189
1190 /*
1191 * Return the status of a device as a text string for each
1192 * target.
1193 */
1194 static int table_status(struct dm_ioctl *param, size_t param_size)
1195 {
1196 int r;
1197 struct mapped_device *md;
1198 struct dm_table *table;
1199
1200 md = find_device(param);
1201 if (!md)
1202 return -ENXIO;
1203
1204 r = __dev_status(md, param);
1205 if (r)
1206 goto out;
1207
1208 table = dm_get_table(md);
1209 if (table) {
1210 retrieve_status(table, param, param_size);
1211 dm_table_put(table);
1212 }
1213
1214 out:
1215 dm_put(md);
1216 return r;
1217 }
1218
1219 /*
1220 * Pass a message to the target that's at the supplied device offset.
1221 */
1222 static int target_message(struct dm_ioctl *param, size_t param_size)
1223 {
1224 int r, argc;
1225 char **argv;
1226 struct mapped_device *md;
1227 struct dm_table *table;
1228 struct dm_target *ti;
1229 struct dm_target_msg *tmsg = (void *) param + param->data_start;
1230
1231 md = find_device(param);
1232 if (!md)
1233 return -ENXIO;
1234
1235 r = __dev_status(md, param);
1236 if (r)
1237 goto out;
1238
1239 if (tmsg < (struct dm_target_msg *) param->data ||
1240 invalid_str(tmsg->message, (void *) param + param_size)) {
1241 DMWARN("Invalid target message parameters.");
1242 r = -EINVAL;
1243 goto out;
1244 }
1245
1246 r = dm_split_args(&argc, &argv, tmsg->message);
1247 if (r) {
1248 DMWARN("Failed to split target message parameters");
1249 goto out;
1250 }
1251
1252 table = dm_get_table(md);
1253 if (!table)
1254 goto out_argv;
1255
1256 ti = dm_table_find_target(table, tmsg->sector);
1257 if (!dm_target_is_valid(ti)) {
1258 DMWARN("Target message sector outside device.");
1259 r = -EINVAL;
1260 } else 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 dm_table_put(table);
1268 out_argv:
1269 kfree(argv);
1270 out:
1271 param->data_size = 0;
1272 dm_put(md);
1273 return r;
1274 }
1275
1276 /*-----------------------------------------------------------------
1277 * Implementation of open/close/ioctl on the special char
1278 * device.
1279 *---------------------------------------------------------------*/
1280 static ioctl_fn lookup_ioctl(unsigned int cmd)
1281 {
1282 static struct {
1283 int cmd;
1284 ioctl_fn fn;
1285 } _ioctls[] = {
1286 {DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
1287 {DM_REMOVE_ALL_CMD, remove_all},
1288 {DM_LIST_DEVICES_CMD, list_devices},
1289
1290 {DM_DEV_CREATE_CMD, dev_create},
1291 {DM_DEV_REMOVE_CMD, dev_remove},
1292 {DM_DEV_RENAME_CMD, dev_rename},
1293 {DM_DEV_SUSPEND_CMD, dev_suspend},
1294 {DM_DEV_STATUS_CMD, dev_status},
1295 {DM_DEV_WAIT_CMD, dev_wait},
1296
1297 {DM_TABLE_LOAD_CMD, table_load},
1298 {DM_TABLE_CLEAR_CMD, table_clear},
1299 {DM_TABLE_DEPS_CMD, table_deps},
1300 {DM_TABLE_STATUS_CMD, table_status},
1301
1302 {DM_LIST_VERSIONS_CMD, list_versions},
1303
1304 {DM_TARGET_MSG_CMD, target_message},
1305 {DM_DEV_SET_GEOMETRY_CMD, dev_set_geometry}
1306 };
1307
1308 return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
1309 }
1310
1311 /*
1312 * As well as checking the version compatibility this always
1313 * copies the kernel interface version out.
1314 */
1315 static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
1316 {
1317 uint32_t version[3];
1318 int r = 0;
1319
1320 if (copy_from_user(version, user->version, sizeof(version)))
1321 return -EFAULT;
1322
1323 if ((DM_VERSION_MAJOR != version[0]) ||
1324 (DM_VERSION_MINOR < version[1])) {
1325 DMWARN("ioctl interface mismatch: "
1326 "kernel(%u.%u.%u), user(%u.%u.%u), cmd(%d)",
1327 DM_VERSION_MAJOR, DM_VERSION_MINOR,
1328 DM_VERSION_PATCHLEVEL,
1329 version[0], version[1], version[2], cmd);
1330 r = -EINVAL;
1331 }
1332
1333 /*
1334 * Fill in the kernel version.
1335 */
1336 version[0] = DM_VERSION_MAJOR;
1337 version[1] = DM_VERSION_MINOR;
1338 version[2] = DM_VERSION_PATCHLEVEL;
1339 if (copy_to_user(user->version, version, sizeof(version)))
1340 return -EFAULT;
1341
1342 return r;
1343 }
1344
1345 static void free_params(struct dm_ioctl *param)
1346 {
1347 vfree(param);
1348 }
1349
1350 static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl **param)
1351 {
1352 struct dm_ioctl tmp, *dmi;
1353
1354 if (copy_from_user(&tmp, user, sizeof(tmp) - sizeof(tmp.data)))
1355 return -EFAULT;
1356
1357 if (tmp.data_size < (sizeof(tmp) - sizeof(tmp.data)))
1358 return -EINVAL;
1359
1360 dmi = vmalloc(tmp.data_size);
1361 if (!dmi)
1362 return -ENOMEM;
1363
1364 if (copy_from_user(dmi, user, tmp.data_size)) {
1365 vfree(dmi);
1366 return -EFAULT;
1367 }
1368
1369 *param = dmi;
1370 return 0;
1371 }
1372
1373 static int validate_params(uint cmd, struct dm_ioctl *param)
1374 {
1375 /* Always clear this flag */
1376 param->flags &= ~DM_BUFFER_FULL_FLAG;
1377
1378 /* Ignores parameters */
1379 if (cmd == DM_REMOVE_ALL_CMD ||
1380 cmd == DM_LIST_DEVICES_CMD ||
1381 cmd == DM_LIST_VERSIONS_CMD)
1382 return 0;
1383
1384 if ((cmd == DM_DEV_CREATE_CMD)) {
1385 if (!*param->name) {
1386 DMWARN("name not supplied when creating device");
1387 return -EINVAL;
1388 }
1389 } else if ((*param->uuid && *param->name)) {
1390 DMWARN("only supply one of name or uuid, cmd(%u)", cmd);
1391 return -EINVAL;
1392 }
1393
1394 /* Ensure strings are terminated */
1395 param->name[DM_NAME_LEN - 1] = '\0';
1396 param->uuid[DM_UUID_LEN - 1] = '\0';
1397
1398 return 0;
1399 }
1400
1401 static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
1402 {
1403 int r = 0;
1404 unsigned int cmd;
1405 struct dm_ioctl *uninitialized_var(param);
1406 ioctl_fn fn = NULL;
1407 size_t param_size;
1408
1409 /* only root can play with this */
1410 if (!capable(CAP_SYS_ADMIN))
1411 return -EACCES;
1412
1413 if (_IOC_TYPE(command) != DM_IOCTL)
1414 return -ENOTTY;
1415
1416 cmd = _IOC_NR(command);
1417
1418 /*
1419 * Check the interface version passed in. This also
1420 * writes out the kernel's interface version.
1421 */
1422 r = check_version(cmd, user);
1423 if (r)
1424 return r;
1425
1426 /*
1427 * Nothing more to do for the version command.
1428 */
1429 if (cmd == DM_VERSION_CMD)
1430 return 0;
1431
1432 fn = lookup_ioctl(cmd);
1433 if (!fn) {
1434 DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
1435 return -ENOTTY;
1436 }
1437
1438 /*
1439 * Trying to avoid low memory issues when a device is
1440 * suspended.
1441 */
1442 current->flags |= PF_MEMALLOC;
1443
1444 /*
1445 * Copy the parameters into kernel space.
1446 */
1447 r = copy_params(user, &param);
1448
1449 current->flags &= ~PF_MEMALLOC;
1450
1451 if (r)
1452 return r;
1453
1454 r = validate_params(cmd, param);
1455 if (r)
1456 goto out;
1457
1458 param_size = param->data_size;
1459 param->data_size = sizeof(*param);
1460 r = fn(param, param_size);
1461
1462 /*
1463 * Copy the results back to userland.
1464 */
1465 if (!r && copy_to_user(user, param, param->data_size))
1466 r = -EFAULT;
1467
1468 out:
1469 free_params(param);
1470 return r;
1471 }
1472
1473 static long dm_ctl_ioctl(struct file *file, uint command, ulong u)
1474 {
1475 return (long)ctl_ioctl(command, (struct dm_ioctl __user *)u);
1476 }
1477
1478 #ifdef CONFIG_COMPAT
1479 static long dm_compat_ctl_ioctl(struct file *file, uint command, ulong u)
1480 {
1481 return (long)dm_ctl_ioctl(file, command, (ulong) compat_ptr(u));
1482 }
1483 #else
1484 #define dm_compat_ctl_ioctl NULL
1485 #endif
1486
1487 static const struct file_operations _ctl_fops = {
1488 .unlocked_ioctl = dm_ctl_ioctl,
1489 .compat_ioctl = dm_compat_ctl_ioctl,
1490 .owner = THIS_MODULE,
1491 };
1492
1493 static struct miscdevice _dm_misc = {
1494 .minor = MISC_DYNAMIC_MINOR,
1495 .name = DM_NAME,
1496 .fops = &_ctl_fops
1497 };
1498
1499 /*
1500 * Create misc character device and link to DM_DIR/control.
1501 */
1502 int __init dm_interface_init(void)
1503 {
1504 int r;
1505
1506 r = dm_hash_init();
1507 if (r)
1508 return r;
1509
1510 r = misc_register(&_dm_misc);
1511 if (r) {
1512 DMERR("misc_register failed for control device");
1513 dm_hash_exit();
1514 return r;
1515 }
1516
1517 DMINFO("%d.%d.%d%s initialised: %s", DM_VERSION_MAJOR,
1518 DM_VERSION_MINOR, DM_VERSION_PATCHLEVEL, DM_VERSION_EXTRA,
1519 DM_DRIVER_EMAIL);
1520 return 0;
1521 }
1522
1523 void dm_interface_exit(void)
1524 {
1525 if (misc_deregister(&_dm_misc) < 0)
1526 DMERR("misc_deregister failed for control device");
1527
1528 dm_hash_exit();
1529 }
1530
1531 /**
1532 * dm_copy_name_and_uuid - Copy mapped device name & uuid into supplied buffers
1533 * @md: Pointer to mapped_device
1534 * @name: Buffer (size DM_NAME_LEN) for name
1535 * @uuid: Buffer (size DM_UUID_LEN) for uuid or empty string if uuid not defined
1536 */
1537 int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
1538 {
1539 int r = 0;
1540 struct hash_cell *hc;
1541
1542 if (!md)
1543 return -ENXIO;
1544
1545 dm_get(md);
1546 down_read(&_hash_lock);
1547 hc = dm_get_mdptr(md);
1548 if (!hc || hc->md != md) {
1549 r = -ENXIO;
1550 goto out;
1551 }
1552
1553 strcpy(name, hc->name);
1554 strcpy(uuid, hc->uuid ? : "");
1555
1556 out:
1557 up_read(&_hash_lock);
1558 dm_put(md);
1559
1560 return r;
1561 }
linux-next