1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2011 Red Hat, Inc.
4  *
5  * This file is released under the GPL.
6  */
7 
8 #include "dm-space-map.h"
9 #include "dm-space-map-common.h"
10 #include "dm-space-map-metadata.h"
11 
12 #include <linux/list.h>
13 #include <linux/slab.h>
14 #include <linux/device-mapper.h>
15 #include <linux/kernel.h>
16 
17 #define DM_MSG_PREFIX "space map metadata"
18 
19 /*----------------------------------------------------------------*/
20 
21 /*
22  * An edge triggered threshold.
23  */
24 struct threshold {
25 	bool threshold_set;
26 	bool value_set;
27 	dm_block_t threshold;
28 	dm_block_t current_value;
29 	dm_sm_threshold_fn fn;
30 	void *context;
31 };
32 
threshold_init(struct threshold * t)33 static void threshold_init(struct threshold *t)
34 {
35 	t->threshold_set = false;
36 	t->value_set = false;
37 }
38 
set_threshold(struct threshold * t,dm_block_t value,dm_sm_threshold_fn fn,void * context)39 static void set_threshold(struct threshold *t, dm_block_t value,
40 			  dm_sm_threshold_fn fn, void *context)
41 {
42 	t->threshold_set = true;
43 	t->threshold = value;
44 	t->fn = fn;
45 	t->context = context;
46 }
47 
below_threshold(struct threshold * t,dm_block_t value)48 static bool below_threshold(struct threshold *t, dm_block_t value)
49 {
50 	return t->threshold_set && value <= t->threshold;
51 }
52 
threshold_already_triggered(struct threshold * t)53 static bool threshold_already_triggered(struct threshold *t)
54 {
55 	return t->value_set && below_threshold(t, t->current_value);
56 }
57 
check_threshold(struct threshold * t,dm_block_t value)58 static void check_threshold(struct threshold *t, dm_block_t value)
59 {
60 	if (below_threshold(t, value) &&
61 	    !threshold_already_triggered(t))
62 		t->fn(t->context);
63 
64 	t->value_set = true;
65 	t->current_value = value;
66 }
67 
68 /*----------------------------------------------------------------*/
69 
70 /*
71  * Space map interface.
72  *
73  * The low level disk format is written using the standard btree and
74  * transaction manager.  This means that performing disk operations may
75  * cause us to recurse into the space map in order to allocate new blocks.
76  * For this reason we have a pool of pre-allocated blocks large enough to
77  * service any metadata_ll_disk operation.
78  */
79 
80 /*
81  * FIXME: we should calculate this based on the size of the device.
82  * Only the metadata space map needs this functionality.
83  */
84 #define MAX_RECURSIVE_ALLOCATIONS 1024
85 
86 enum block_op_type {
87 	BOP_INC,
88 	BOP_DEC
89 };
90 
91 struct block_op {
92 	enum block_op_type type;
93 	dm_block_t b;
94 	dm_block_t e;
95 };
96 
97 struct bop_ring_buffer {
98 	unsigned int begin;
99 	unsigned int end;
100 	struct block_op bops[MAX_RECURSIVE_ALLOCATIONS + 1];
101 };
102 
brb_init(struct bop_ring_buffer * brb)103 static void brb_init(struct bop_ring_buffer *brb)
104 {
105 	brb->begin = 0;
106 	brb->end = 0;
107 }
108 
brb_empty(struct bop_ring_buffer * brb)109 static bool brb_empty(struct bop_ring_buffer *brb)
110 {
111 	return brb->begin == brb->end;
112 }
113 
brb_next(struct bop_ring_buffer * brb,unsigned int old)114 static unsigned int brb_next(struct bop_ring_buffer *brb, unsigned int old)
115 {
116 	unsigned int r = old + 1;
117 
118 	return r >= ARRAY_SIZE(brb->bops) ? 0 : r;
119 }
120 
brb_push(struct bop_ring_buffer * brb,enum block_op_type type,dm_block_t b,dm_block_t e)121 static int brb_push(struct bop_ring_buffer *brb,
122 		    enum block_op_type type, dm_block_t b, dm_block_t e)
123 {
124 	struct block_op *bop;
125 	unsigned int next = brb_next(brb, brb->end);
126 
127 	/*
128 	 * We don't allow the last bop to be filled, this way we can
129 	 * differentiate between full and empty.
130 	 */
131 	if (next == brb->begin)
132 		return -ENOMEM;
133 
134 	bop = brb->bops + brb->end;
135 	bop->type = type;
136 	bop->b = b;
137 	bop->e = e;
138 
139 	brb->end = next;
140 
141 	return 0;
142 }
143 
brb_peek(struct bop_ring_buffer * brb,struct block_op * result)144 static int brb_peek(struct bop_ring_buffer *brb, struct block_op *result)
145 {
146 	struct block_op *bop;
147 
148 	if (brb_empty(brb))
149 		return -ENODATA;
150 
151 	bop = brb->bops + brb->begin;
152 	memcpy(result, bop, sizeof(*result));
153 	return 0;
154 }
155 
brb_pop(struct bop_ring_buffer * brb)156 static int brb_pop(struct bop_ring_buffer *brb)
157 {
158 	if (brb_empty(brb))
159 		return -ENODATA;
160 
161 	brb->begin = brb_next(brb, brb->begin);
162 
163 	return 0;
164 }
165 
166 /*----------------------------------------------------------------*/
167 
168 struct sm_metadata {
169 	struct dm_space_map sm;
170 
171 	struct ll_disk ll;
172 	struct ll_disk old_ll;
173 
174 	dm_block_t begin;
175 
176 	unsigned int recursion_count;
177 	unsigned int allocated_this_transaction;
178 	struct bop_ring_buffer uncommitted;
179 
180 	struct threshold threshold;
181 };
182 
add_bop(struct sm_metadata * smm,enum block_op_type type,dm_block_t b,dm_block_t e)183 static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b, dm_block_t e)
184 {
185 	int r = brb_push(&smm->uncommitted, type, b, e);
186 
187 	if (r) {
188 		DMERR("too many recursive allocations");
189 		return -ENOMEM;
190 	}
191 
192 	return 0;
193 }
194 
commit_bop(struct sm_metadata * smm,struct block_op * op)195 static int commit_bop(struct sm_metadata *smm, struct block_op *op)
196 {
197 	int r = 0;
198 	int32_t nr_allocations;
199 
200 	switch (op->type) {
201 	case BOP_INC:
202 		r = sm_ll_inc(&smm->ll, op->b, op->e, &nr_allocations);
203 		break;
204 
205 	case BOP_DEC:
206 		r = sm_ll_dec(&smm->ll, op->b, op->e, &nr_allocations);
207 		break;
208 	}
209 
210 	return r;
211 }
212 
in(struct sm_metadata * smm)213 static void in(struct sm_metadata *smm)
214 {
215 	smm->recursion_count++;
216 }
217 
apply_bops(struct sm_metadata * smm)218 static int apply_bops(struct sm_metadata *smm)
219 {
220 	int r = 0;
221 
222 	while (!brb_empty(&smm->uncommitted)) {
223 		struct block_op bop;
224 
225 		r = brb_peek(&smm->uncommitted, &bop);
226 		if (r) {
227 			DMERR("bug in bop ring buffer");
228 			break;
229 		}
230 
231 		r = commit_bop(smm, &bop);
232 		if (r)
233 			break;
234 
235 		brb_pop(&smm->uncommitted);
236 	}
237 
238 	return r;
239 }
240 
out(struct sm_metadata * smm)241 static int out(struct sm_metadata *smm)
242 {
243 	int r = 0;
244 
245 	/*
246 	 * If we're not recursing then very bad things are happening.
247 	 */
248 	if (!smm->recursion_count) {
249 		DMERR("lost track of recursion depth");
250 		return -ENOMEM;
251 	}
252 
253 	if (smm->recursion_count == 1)
254 		r = apply_bops(smm);
255 
256 	smm->recursion_count--;
257 
258 	return r;
259 }
260 
261 /*
262  * When using the out() function above, we often want to combine an error
263  * code for the operation run in the recursive context with that from
264  * out().
265  */
combine_errors(int r1,int r2)266 static int combine_errors(int r1, int r2)
267 {
268 	return r1 ? r1 : r2;
269 }
270 
recursing(struct sm_metadata * smm)271 static int recursing(struct sm_metadata *smm)
272 {
273 	return smm->recursion_count;
274 }
275 
sm_metadata_destroy(struct dm_space_map * sm)276 static void sm_metadata_destroy(struct dm_space_map *sm)
277 {
278 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
279 
280 	kvfree(smm);
281 }
282 
sm_metadata_get_nr_blocks(struct dm_space_map * sm,dm_block_t * count)283 static int sm_metadata_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
284 {
285 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
286 
287 	*count = smm->ll.nr_blocks;
288 
289 	return 0;
290 }
291 
sm_metadata_get_nr_free(struct dm_space_map * sm,dm_block_t * count)292 static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
293 {
294 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
295 
296 	*count = smm->old_ll.nr_blocks - smm->old_ll.nr_allocated -
297 		 smm->allocated_this_transaction;
298 
299 	return 0;
300 }
301 
sm_metadata_get_count(struct dm_space_map * sm,dm_block_t b,uint32_t * result)302 static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
303 				 uint32_t *result)
304 {
305 	int r;
306 	unsigned int i;
307 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
308 	unsigned int adjustment = 0;
309 
310 	/*
311 	 * We may have some uncommitted adjustments to add.  This list
312 	 * should always be really short.
313 	 */
314 	for (i = smm->uncommitted.begin;
315 	     i != smm->uncommitted.end;
316 	     i = brb_next(&smm->uncommitted, i)) {
317 		struct block_op *op = smm->uncommitted.bops + i;
318 
319 		if (b < op->b || b >= op->e)
320 			continue;
321 
322 		switch (op->type) {
323 		case BOP_INC:
324 			adjustment++;
325 			break;
326 
327 		case BOP_DEC:
328 			adjustment--;
329 			break;
330 		}
331 	}
332 
333 	r = sm_ll_lookup(&smm->ll, b, result);
334 	if (r)
335 		return r;
336 
337 	*result += adjustment;
338 
339 	return 0;
340 }
341 
sm_metadata_count_is_more_than_one(struct dm_space_map * sm,dm_block_t b,int * result)342 static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
343 					      dm_block_t b, int *result)
344 {
345 	int r, adjustment = 0;
346 	unsigned int i;
347 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
348 	uint32_t rc;
349 
350 	/*
351 	 * We may have some uncommitted adjustments to add.  This list
352 	 * should always be really short.
353 	 */
354 	for (i = smm->uncommitted.begin;
355 	     i != smm->uncommitted.end;
356 	     i = brb_next(&smm->uncommitted, i)) {
357 
358 		struct block_op *op = smm->uncommitted.bops + i;
359 
360 		if (b < op->b || b >= op->e)
361 			continue;
362 
363 		switch (op->type) {
364 		case BOP_INC:
365 			adjustment++;
366 			break;
367 
368 		case BOP_DEC:
369 			adjustment--;
370 			break;
371 		}
372 	}
373 
374 	if (adjustment > 1) {
375 		*result = 1;
376 		return 0;
377 	}
378 
379 	r = sm_ll_lookup_bitmap(&smm->ll, b, &rc);
380 	if (r)
381 		return r;
382 
383 	if (rc == 3)
384 		/*
385 		 * We err on the side of caution, and always return true.
386 		 */
387 		*result = 1;
388 	else
389 		*result = rc + adjustment > 1;
390 
391 	return 0;
392 }
393 
sm_metadata_set_count(struct dm_space_map * sm,dm_block_t b,uint32_t count)394 static int sm_metadata_set_count(struct dm_space_map *sm, dm_block_t b,
395 				 uint32_t count)
396 {
397 	int r, r2;
398 	int32_t nr_allocations;
399 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
400 
401 	if (smm->recursion_count) {
402 		DMERR("cannot recurse set_count()");
403 		return -EINVAL;
404 	}
405 
406 	in(smm);
407 	r = sm_ll_insert(&smm->ll, b, count, &nr_allocations);
408 	r2 = out(smm);
409 
410 	return combine_errors(r, r2);
411 }
412 
sm_metadata_inc_blocks(struct dm_space_map * sm,dm_block_t b,dm_block_t e)413 static int sm_metadata_inc_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
414 {
415 	int r, r2 = 0;
416 	int32_t nr_allocations;
417 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
418 
419 	if (recursing(smm)) {
420 		r = add_bop(smm, BOP_INC, b, e);
421 		if (r)
422 			return r;
423 	} else {
424 		in(smm);
425 		r = sm_ll_inc(&smm->ll, b, e, &nr_allocations);
426 		r2 = out(smm);
427 	}
428 
429 	return combine_errors(r, r2);
430 }
431 
sm_metadata_dec_blocks(struct dm_space_map * sm,dm_block_t b,dm_block_t e)432 static int sm_metadata_dec_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
433 {
434 	int r, r2 = 0;
435 	int32_t nr_allocations;
436 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
437 
438 	if (recursing(smm))
439 		r = add_bop(smm, BOP_DEC, b, e);
440 	else {
441 		in(smm);
442 		r = sm_ll_dec(&smm->ll, b, e, &nr_allocations);
443 		r2 = out(smm);
444 	}
445 
446 	return combine_errors(r, r2);
447 }
448 
sm_metadata_new_block_(struct dm_space_map * sm,dm_block_t * b)449 static int sm_metadata_new_block_(struct dm_space_map *sm, dm_block_t *b)
450 {
451 	int r, r2 = 0;
452 	int32_t nr_allocations;
453 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
454 
455 	/*
456 	 * Any block we allocate has to be free in both the old and current ll.
457 	 */
458 	r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, smm->begin, smm->ll.nr_blocks, b);
459 	if (r == -ENOSPC) {
460 		/*
461 		 * There's no free block between smm->begin and the end of the metadata device.
462 		 * We search before smm->begin in case something has been freed.
463 		 */
464 		r = sm_ll_find_common_free_block(&smm->old_ll, &smm->ll, 0, smm->begin, b);
465 	}
466 
467 	if (r)
468 		return r;
469 
470 	smm->begin = *b + 1;
471 
472 	if (recursing(smm))
473 		r = add_bop(smm, BOP_INC, *b, *b + 1);
474 	else {
475 		in(smm);
476 		r = sm_ll_inc(&smm->ll, *b, *b + 1, &nr_allocations);
477 		r2 = out(smm);
478 	}
479 
480 	if (!r)
481 		smm->allocated_this_transaction++;
482 
483 	return combine_errors(r, r2);
484 }
485 
sm_metadata_new_block(struct dm_space_map * sm,dm_block_t * b)486 static int sm_metadata_new_block(struct dm_space_map *sm, dm_block_t *b)
487 {
488 	dm_block_t count;
489 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
490 
491 	int r = sm_metadata_new_block_(sm, b);
492 
493 	if (r) {
494 		DMERR_LIMIT("unable to allocate new metadata block");
495 		return r;
496 	}
497 
498 	r = sm_metadata_get_nr_free(sm, &count);
499 	if (r) {
500 		DMERR_LIMIT("couldn't get free block count");
501 		return r;
502 	}
503 
504 	check_threshold(&smm->threshold, count);
505 
506 	return r;
507 }
508 
sm_metadata_commit(struct dm_space_map * sm)509 static int sm_metadata_commit(struct dm_space_map *sm)
510 {
511 	int r;
512 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
513 
514 	r = sm_ll_commit(&smm->ll);
515 	if (r)
516 		return r;
517 
518 	memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
519 	smm->allocated_this_transaction = 0;
520 
521 	return 0;
522 }
523 
sm_metadata_register_threshold_callback(struct dm_space_map * sm,dm_block_t threshold,dm_sm_threshold_fn fn,void * context)524 static int sm_metadata_register_threshold_callback(struct dm_space_map *sm,
525 						   dm_block_t threshold,
526 						   dm_sm_threshold_fn fn,
527 						   void *context)
528 {
529 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
530 
531 	set_threshold(&smm->threshold, threshold, fn, context);
532 
533 	return 0;
534 }
535 
sm_metadata_root_size(struct dm_space_map * sm,size_t * result)536 static int sm_metadata_root_size(struct dm_space_map *sm, size_t *result)
537 {
538 	*result = sizeof(struct disk_sm_root);
539 
540 	return 0;
541 }
542 
sm_metadata_copy_root(struct dm_space_map * sm,void * where_le,size_t max)543 static int sm_metadata_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
544 {
545 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
546 	struct disk_sm_root root_le;
547 
548 	root_le.nr_blocks = cpu_to_le64(smm->ll.nr_blocks);
549 	root_le.nr_allocated = cpu_to_le64(smm->ll.nr_allocated);
550 	root_le.bitmap_root = cpu_to_le64(smm->ll.bitmap_root);
551 	root_le.ref_count_root = cpu_to_le64(smm->ll.ref_count_root);
552 
553 	if (max < sizeof(root_le))
554 		return -ENOSPC;
555 
556 	memcpy(where_le, &root_le, sizeof(root_le));
557 
558 	return 0;
559 }
560 
561 static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks);
562 
563 static const struct dm_space_map ops = {
564 	.destroy = sm_metadata_destroy,
565 	.extend = sm_metadata_extend,
566 	.get_nr_blocks = sm_metadata_get_nr_blocks,
567 	.get_nr_free = sm_metadata_get_nr_free,
568 	.get_count = sm_metadata_get_count,
569 	.count_is_more_than_one = sm_metadata_count_is_more_than_one,
570 	.set_count = sm_metadata_set_count,
571 	.inc_blocks = sm_metadata_inc_blocks,
572 	.dec_blocks = sm_metadata_dec_blocks,
573 	.new_block = sm_metadata_new_block,
574 	.commit = sm_metadata_commit,
575 	.root_size = sm_metadata_root_size,
576 	.copy_root = sm_metadata_copy_root,
577 	.register_threshold_callback = sm_metadata_register_threshold_callback
578 };
579 
580 /*----------------------------------------------------------------*/
581 
582 /*
583  * When a new space map is created that manages its own space.  We use
584  * this tiny bootstrap allocator.
585  */
sm_bootstrap_destroy(struct dm_space_map * sm)586 static void sm_bootstrap_destroy(struct dm_space_map *sm)
587 {
588 }
589 
sm_bootstrap_extend(struct dm_space_map * sm,dm_block_t extra_blocks)590 static int sm_bootstrap_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
591 {
592 	DMERR("bootstrap doesn't support extend");
593 
594 	return -EINVAL;
595 }
596 
sm_bootstrap_get_nr_blocks(struct dm_space_map * sm,dm_block_t * count)597 static int sm_bootstrap_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
598 {
599 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
600 
601 	*count = smm->ll.nr_blocks;
602 
603 	return 0;
604 }
605 
sm_bootstrap_get_nr_free(struct dm_space_map * sm,dm_block_t * count)606 static int sm_bootstrap_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
607 {
608 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
609 
610 	*count = smm->ll.nr_blocks - smm->begin;
611 
612 	return 0;
613 }
614 
sm_bootstrap_get_count(struct dm_space_map * sm,dm_block_t b,uint32_t * result)615 static int sm_bootstrap_get_count(struct dm_space_map *sm, dm_block_t b,
616 				  uint32_t *result)
617 {
618 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
619 
620 	*result = (b < smm->begin) ? 1 : 0;
621 
622 	return 0;
623 }
624 
sm_bootstrap_count_is_more_than_one(struct dm_space_map * sm,dm_block_t b,int * result)625 static int sm_bootstrap_count_is_more_than_one(struct dm_space_map *sm,
626 					       dm_block_t b, int *result)
627 {
628 	*result = 0;
629 
630 	return 0;
631 }
632 
sm_bootstrap_set_count(struct dm_space_map * sm,dm_block_t b,uint32_t count)633 static int sm_bootstrap_set_count(struct dm_space_map *sm, dm_block_t b,
634 				  uint32_t count)
635 {
636 	DMERR("bootstrap doesn't support set_count");
637 
638 	return -EINVAL;
639 }
640 
sm_bootstrap_new_block(struct dm_space_map * sm,dm_block_t * b)641 static int sm_bootstrap_new_block(struct dm_space_map *sm, dm_block_t *b)
642 {
643 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
644 
645 	/*
646 	 * We know the entire device is unused.
647 	 */
648 	if (smm->begin == smm->ll.nr_blocks)
649 		return -ENOSPC;
650 
651 	*b = smm->begin++;
652 
653 	return 0;
654 }
655 
sm_bootstrap_inc_blocks(struct dm_space_map * sm,dm_block_t b,dm_block_t e)656 static int sm_bootstrap_inc_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
657 {
658 	int r;
659 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
660 
661 	r = add_bop(smm, BOP_INC, b, e);
662 	if (r)
663 		return r;
664 
665 	return 0;
666 }
667 
sm_bootstrap_dec_blocks(struct dm_space_map * sm,dm_block_t b,dm_block_t e)668 static int sm_bootstrap_dec_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
669 {
670 	int r;
671 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
672 
673 	r = add_bop(smm, BOP_DEC, b, e);
674 	if (r)
675 		return r;
676 
677 	return 0;
678 }
679 
sm_bootstrap_commit(struct dm_space_map * sm)680 static int sm_bootstrap_commit(struct dm_space_map *sm)
681 {
682 	return 0;
683 }
684 
sm_bootstrap_root_size(struct dm_space_map * sm,size_t * result)685 static int sm_bootstrap_root_size(struct dm_space_map *sm, size_t *result)
686 {
687 	DMERR("bootstrap doesn't support root_size");
688 
689 	return -EINVAL;
690 }
691 
sm_bootstrap_copy_root(struct dm_space_map * sm,void * where,size_t max)692 static int sm_bootstrap_copy_root(struct dm_space_map *sm, void *where,
693 				  size_t max)
694 {
695 	DMERR("bootstrap doesn't support copy_root");
696 
697 	return -EINVAL;
698 }
699 
700 static const struct dm_space_map bootstrap_ops = {
701 	.destroy = sm_bootstrap_destroy,
702 	.extend = sm_bootstrap_extend,
703 	.get_nr_blocks = sm_bootstrap_get_nr_blocks,
704 	.get_nr_free = sm_bootstrap_get_nr_free,
705 	.get_count = sm_bootstrap_get_count,
706 	.count_is_more_than_one = sm_bootstrap_count_is_more_than_one,
707 	.set_count = sm_bootstrap_set_count,
708 	.inc_blocks = sm_bootstrap_inc_blocks,
709 	.dec_blocks = sm_bootstrap_dec_blocks,
710 	.new_block = sm_bootstrap_new_block,
711 	.commit = sm_bootstrap_commit,
712 	.root_size = sm_bootstrap_root_size,
713 	.copy_root = sm_bootstrap_copy_root,
714 	.register_threshold_callback = NULL
715 };
716 
717 /*----------------------------------------------------------------*/
718 
sm_metadata_extend(struct dm_space_map * sm,dm_block_t extra_blocks)719 static int sm_metadata_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
720 {
721 	int r;
722 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
723 	dm_block_t old_len = smm->ll.nr_blocks;
724 
725 	/*
726 	 * Flick into a mode where all blocks get allocated in the new area.
727 	 */
728 	smm->begin = old_len;
729 	memcpy(sm, &bootstrap_ops, sizeof(*sm));
730 
731 	/*
732 	 * Extend.
733 	 */
734 	r = sm_ll_extend(&smm->ll, extra_blocks);
735 	if (r)
736 		goto out;
737 
738 	/*
739 	 * We repeatedly increment then commit until the commit doesn't
740 	 * allocate any new blocks.
741 	 */
742 	do {
743 		r = add_bop(smm, BOP_INC, old_len, smm->begin);
744 		if (r)
745 			goto out;
746 
747 		old_len = smm->begin;
748 
749 		r = apply_bops(smm);
750 		if (r) {
751 			DMERR("%s: apply_bops failed", __func__);
752 			goto out;
753 		}
754 
755 		r = sm_ll_commit(&smm->ll);
756 		if (r)
757 			goto out;
758 
759 	} while (old_len != smm->begin);
760 
761 out:
762 	/*
763 	 * Switch back to normal behaviour.
764 	 */
765 	memcpy(sm, &ops, sizeof(*sm));
766 	return r;
767 }
768 
769 /*----------------------------------------------------------------*/
770 
dm_sm_metadata_init(void)771 struct dm_space_map *dm_sm_metadata_init(void)
772 {
773 	struct sm_metadata *smm;
774 
775 	smm = kvmalloc(sizeof(*smm), GFP_KERNEL);
776 	if (!smm)
777 		return ERR_PTR(-ENOMEM);
778 
779 	memcpy(&smm->sm, &ops, sizeof(smm->sm));
780 
781 	return &smm->sm;
782 }
783 
dm_sm_metadata_create(struct dm_space_map * sm,struct dm_transaction_manager * tm,dm_block_t nr_blocks,dm_block_t superblock)784 int dm_sm_metadata_create(struct dm_space_map *sm,
785 			  struct dm_transaction_manager *tm,
786 			  dm_block_t nr_blocks,
787 			  dm_block_t superblock)
788 {
789 	int r;
790 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
791 
792 	smm->begin = superblock + 1;
793 	smm->recursion_count = 0;
794 	smm->allocated_this_transaction = 0;
795 	brb_init(&smm->uncommitted);
796 	threshold_init(&smm->threshold);
797 
798 	memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
799 
800 	r = sm_ll_new_metadata(&smm->ll, tm);
801 	if (!r) {
802 		if (nr_blocks > DM_SM_METADATA_MAX_BLOCKS)
803 			nr_blocks = DM_SM_METADATA_MAX_BLOCKS;
804 		r = sm_ll_extend(&smm->ll, nr_blocks);
805 	}
806 	memcpy(&smm->sm, &ops, sizeof(smm->sm));
807 	if (r)
808 		return r;
809 
810 	/*
811 	 * Now we need to update the newly created data structures with the
812 	 * allocated blocks that they were built from.
813 	 */
814 	r = add_bop(smm, BOP_INC, superblock, smm->begin);
815 	if (r)
816 		return r;
817 
818 	r = apply_bops(smm);
819 	if (r) {
820 		DMERR("%s: apply_bops failed", __func__);
821 		return r;
822 	}
823 
824 	return sm_metadata_commit(sm);
825 }
826 
dm_sm_metadata_open(struct dm_space_map * sm,struct dm_transaction_manager * tm,void * root_le,size_t len)827 int dm_sm_metadata_open(struct dm_space_map *sm,
828 			struct dm_transaction_manager *tm,
829 			void *root_le, size_t len)
830 {
831 	int r;
832 	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
833 
834 	r = sm_ll_open_metadata(&smm->ll, tm, root_le, len);
835 	if (r)
836 		return r;
837 
838 	smm->begin = 0;
839 	smm->recursion_count = 0;
840 	smm->allocated_this_transaction = 0;
841 	brb_init(&smm->uncommitted);
842 	threshold_init(&smm->threshold);
843 
844 	memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));
845 	return 0;
846 }
847