1/*
  2 * Copyright (C) 2011 Red Hat, Inc.
  3 *
  4 * This file is released under the GPL.
  5 */
  6
  7#include "dm-space-map-common.h"
  8#include "dm-space-map-disk.h"
  9#include "dm-space-map.h"
 10#include "dm-transaction-manager.h"
 11
 12#include <linux/list.h>
 13#include <linux/slab.h>
 14#include <linux/export.h>
 15#include <linux/device-mapper.h>
 16
 17#define DM_MSG_PREFIX "space map disk"
 18
 19/*----------------------------------------------------------------*/
 20
 21/*
 22 * Space map interface.
 23 */
 24struct sm_disk {
 25	struct dm_space_map sm;
 26
 27	struct ll_disk ll;
 28	struct ll_disk old_ll;
 29
 30	dm_block_t begin;
 31	dm_block_t nr_allocated_this_transaction;
 32};
 33
 34static void sm_disk_destroy(struct dm_space_map *sm)
 35{
 36	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 37
 38	kfree(smd);
 39}
 40
 41static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
 42{
 43	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 44
 45	return sm_ll_extend(&smd->ll, extra_blocks);
 46}
 47
 48static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
 49{
 50	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 51	*count = smd->old_ll.nr_blocks;
 52
 53	return 0;
 54}
 55
 56static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
 57{
 58	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 59	*count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction;
 60
 61	return 0;
 62}
 63
 64static int sm_disk_get_count(struct dm_space_map *sm, dm_block_t b,
 65			     uint32_t *result)
 66{
 67	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 68	return sm_ll_lookup(&smd->ll, b, result);
 69}
 70
 71static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b,
 72					  int *result)
 73{
 74	int r;
 75	uint32_t count;
 76
 77	r = sm_disk_get_count(sm, b, &count);
 78	if (r)
 79		return r;
 80
 81	*result = count > 1;
 82
 83	return 0;
 84}
 85
 86static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b,
 87			     uint32_t count)
 88{
 89	int r;
 90	uint32_t old_count;
 91	enum allocation_event ev;
 92	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 93
 94	r = sm_ll_insert(&smd->ll, b, count, &ev);
 95	if (!r) {
 96		switch (ev) {
 97		case SM_NONE:
 98			break;
 99
100		case SM_ALLOC:
101			/*
102			 * This _must_ be free in the prior transaction
103			 * otherwise we've lost atomicity.
104			 */
105			smd->nr_allocated_this_transaction++;
106			break;
107
108		case SM_FREE:
109			/*
110			 * It's only free if it's also free in the last
111			 * transaction.
112			 */
113			r = sm_ll_lookup(&smd->old_ll, b, &old_count);
114			if (r)
115				return r;
116
117			if (!old_count)
118				smd->nr_allocated_this_transaction--;
119			break;
120		}
121	}
122
123	return r;
124}
125
126static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b)
127{
128	int r;
129	enum allocation_event ev;
130	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
131
132	r = sm_ll_inc(&smd->ll, b, &ev);
133	if (!r && (ev == SM_ALLOC))
134		/*
135		 * This _must_ be free in the prior transaction
136		 * otherwise we've lost atomicity.
137		 */
138		smd->nr_allocated_this_transaction++;
139
140	return r;
141}
142
143static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b)
144{
145	int r;
146	uint32_t old_count;
147	enum allocation_event ev;
148	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
149
150	r = sm_ll_dec(&smd->ll, b, &ev);
151	if (!r && (ev == SM_FREE)) {
152		/*
153		 * It's only free if it's also free in the last
154		 * transaction.
155		 */
156		r = sm_ll_lookup(&smd->old_ll, b, &old_count);
157		if (!r && !old_count)
158			smd->nr_allocated_this_transaction--;
159	}
160
161	return r;
162}
163
164static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)
165{
166	int r;
167	enum allocation_event ev;
168	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
169
170	/*
171	 * Any block we allocate has to be free in both the old and current ll.
172	 */
173	r = sm_ll_find_common_free_block(&smd->old_ll, &smd->ll, smd->begin, smd->ll.nr_blocks, b);
174	if (r)
175		return r;
176
177	smd->begin = *b + 1;
178	r = sm_ll_inc(&smd->ll, *b, &ev);
179	if (!r) {
180		BUG_ON(ev != SM_ALLOC);
181		smd->nr_allocated_this_transaction++;
182	}
183
184	return r;
185}
186
187static int sm_disk_commit(struct dm_space_map *sm)
188{
189	int r;
190	dm_block_t nr_free;
191	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
192
193	r = sm_disk_get_nr_free(sm, &nr_free);
194	if (r)
195		return r;
196
197	r = sm_ll_commit(&smd->ll);
198	if (r)
199		return r;
200
201	memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll));
202	smd->begin = 0;
203	smd->nr_allocated_this_transaction = 0;
204
205	r = sm_disk_get_nr_free(sm, &nr_free);
206	if (r)
207		return r;
208
209	return 0;
210}
211
212static int sm_disk_root_size(struct dm_space_map *sm, size_t *result)
213{
214	*result = sizeof(struct disk_sm_root);
215
216	return 0;
217}
218
219static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
220{
221	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
222	struct disk_sm_root root_le;
223
224	root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks);
225	root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated);
226	root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root);
227	root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root);
228
229	if (max < sizeof(root_le))
230		return -ENOSPC;
231
232	memcpy(where_le, &root_le, sizeof(root_le));
233
234	return 0;
235}
236
237/*----------------------------------------------------------------*/
238
239static struct dm_space_map ops = {
240	.destroy = sm_disk_destroy,
241	.extend = sm_disk_extend,
242	.get_nr_blocks = sm_disk_get_nr_blocks,
243	.get_nr_free = sm_disk_get_nr_free,
244	.get_count = sm_disk_get_count,
245	.count_is_more_than_one = sm_disk_count_is_more_than_one,
246	.set_count = sm_disk_set_count,
247	.inc_block = sm_disk_inc_block,
248	.dec_block = sm_disk_dec_block,
249	.new_block = sm_disk_new_block,
250	.commit = sm_disk_commit,
251	.root_size = sm_disk_root_size,
252	.copy_root = sm_disk_copy_root,
253	.register_threshold_callback = NULL
254};
255
256struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,
257				       dm_block_t nr_blocks)
258{
259	int r;
260	struct sm_disk *smd;
261
262	smd = kmalloc(sizeof(*smd), GFP_KERNEL);
263	if (!smd)
264		return ERR_PTR(-ENOMEM);
265
266	smd->begin = 0;
267	smd->nr_allocated_this_transaction = 0;
268	memcpy(&smd->sm, &ops, sizeof(smd->sm));
269
270	r = sm_ll_new_disk(&smd->ll, tm);
271	if (r)
272		goto bad;
273
274	r = sm_ll_extend(&smd->ll, nr_blocks);
275	if (r)
276		goto bad;
277
278	r = sm_disk_commit(&smd->sm);
279	if (r)
280		goto bad;
281
282	return &smd->sm;
283
284bad:
285	kfree(smd);
286	return ERR_PTR(r);
287}
288EXPORT_SYMBOL_GPL(dm_sm_disk_create);
289
290struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm,
291				     void *root_le, size_t len)
292{
293	int r;
294	struct sm_disk *smd;
295
296	smd = kmalloc(sizeof(*smd), GFP_KERNEL);
297	if (!smd)
298		return ERR_PTR(-ENOMEM);
299
300	smd->begin = 0;
301	smd->nr_allocated_this_transaction = 0;
302	memcpy(&smd->sm, &ops, sizeof(smd->sm));
303
304	r = sm_ll_open_disk(&smd->ll, tm, root_le, len);
305	if (r)
306		goto bad;
307
308	r = sm_disk_commit(&smd->sm);
309	if (r)
310		goto bad;
311
312	return &smd->sm;
313
314bad:
315	kfree(smd);
316	return ERR_PTR(r);
317}
318EXPORT_SYMBOL_GPL(dm_sm_disk_open);
319
320/*----------------------------------------------------------------*/