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Joe Thornber3241b1d2011-10-31 20:19:11 +00001/*
2 * Copyright (C) 2011 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6#include "dm-transaction-manager.h"
7#include "dm-space-map.h"
Joe Thornber3241b1d2011-10-31 20:19:11 +00008#include "dm-space-map-disk.h"
9#include "dm-space-map-metadata.h"
10#include "dm-persistent-data-internal.h"
11
Paul Gortmaker1944ce62011-09-28 18:29:32 -040012#include <linux/export.h>
Joe Thornber46460152014-10-06 15:27:26 +010013#include <linux/mutex.h>
14#include <linux/hash.h>
Joe Thornber3241b1d2011-10-31 20:19:11 +000015#include <linux/slab.h>
16#include <linux/device-mapper.h>
17
18#define DM_MSG_PREFIX "transaction manager"
19
20/*----------------------------------------------------------------*/
21
Joe Thornber46460152014-10-06 15:27:26 +010022#define PREFETCH_SIZE 128
23#define PREFETCH_BITS 7
24#define PREFETCH_SENTINEL ((dm_block_t) -1ULL)
25
26struct prefetch_set {
27 struct mutex lock;
28 dm_block_t blocks[PREFETCH_SIZE];
29};
30
31static unsigned prefetch_hash(dm_block_t b)
32{
33 return hash_64(b, PREFETCH_BITS);
34}
35
36static void prefetch_wipe(struct prefetch_set *p)
37{
38 unsigned i;
39 for (i = 0; i < PREFETCH_SIZE; i++)
40 p->blocks[i] = PREFETCH_SENTINEL;
41}
42
43static void prefetch_init(struct prefetch_set *p)
44{
45 mutex_init(&p->lock);
46 prefetch_wipe(p);
47}
48
49static void prefetch_add(struct prefetch_set *p, dm_block_t b)
50{
51 unsigned h = prefetch_hash(b);
52
53 mutex_lock(&p->lock);
54 if (p->blocks[h] == PREFETCH_SENTINEL)
55 p->blocks[h] = b;
56
57 mutex_unlock(&p->lock);
58}
59
60static void prefetch_issue(struct prefetch_set *p, struct dm_block_manager *bm)
61{
62 unsigned i;
63
64 mutex_lock(&p->lock);
65
66 for (i = 0; i < PREFETCH_SIZE; i++)
67 if (p->blocks[i] != PREFETCH_SENTINEL) {
68 dm_bm_prefetch(bm, p->blocks[i]);
69 p->blocks[i] = PREFETCH_SENTINEL;
70 }
71
72 mutex_unlock(&p->lock);
73}
74
75/*----------------------------------------------------------------*/
76
Joe Thornber3241b1d2011-10-31 20:19:11 +000077struct shadow_info {
78 struct hlist_node hlist;
79 dm_block_t where;
80};
81
82/*
83 * It would be nice if we scaled with the size of transaction.
84 */
Andrew Mortondf855792013-02-22 16:32:03 -080085#define DM_HASH_SIZE 256
86#define DM_HASH_MASK (DM_HASH_SIZE - 1)
Joe Thornber3241b1d2011-10-31 20:19:11 +000087
88struct dm_transaction_manager {
89 int is_clone;
90 struct dm_transaction_manager *real;
91
92 struct dm_block_manager *bm;
93 struct dm_space_map *sm;
94
95 spinlock_t lock;
Andrew Mortondf855792013-02-22 16:32:03 -080096 struct hlist_head buckets[DM_HASH_SIZE];
Joe Thornber46460152014-10-06 15:27:26 +010097
98 struct prefetch_set prefetches;
Joe Thornber3241b1d2011-10-31 20:19:11 +000099};
100
101/*----------------------------------------------------------------*/
102
103static int is_shadow(struct dm_transaction_manager *tm, dm_block_t b)
104{
105 int r = 0;
Andrew Mortondf855792013-02-22 16:32:03 -0800106 unsigned bucket = dm_hash_block(b, DM_HASH_MASK);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000107 struct shadow_info *si;
Joe Thornber3241b1d2011-10-31 20:19:11 +0000108
109 spin_lock(&tm->lock);
Sasha Levinb67bfe02013-02-27 17:06:00 -0800110 hlist_for_each_entry(si, tm->buckets + bucket, hlist)
Joe Thornber3241b1d2011-10-31 20:19:11 +0000111 if (si->where == b) {
112 r = 1;
113 break;
114 }
115 spin_unlock(&tm->lock);
116
117 return r;
118}
119
120/*
121 * This can silently fail if there's no memory. We're ok with this since
122 * creating redundant shadows causes no harm.
123 */
124static void insert_shadow(struct dm_transaction_manager *tm, dm_block_t b)
125{
126 unsigned bucket;
127 struct shadow_info *si;
128
129 si = kmalloc(sizeof(*si), GFP_NOIO);
130 if (si) {
131 si->where = b;
Andrew Mortondf855792013-02-22 16:32:03 -0800132 bucket = dm_hash_block(b, DM_HASH_MASK);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000133 spin_lock(&tm->lock);
134 hlist_add_head(&si->hlist, tm->buckets + bucket);
135 spin_unlock(&tm->lock);
136 }
137}
138
139static void wipe_shadow_table(struct dm_transaction_manager *tm)
140{
141 struct shadow_info *si;
Sasha Levinb67bfe02013-02-27 17:06:00 -0800142 struct hlist_node *tmp;
Joe Thornber3241b1d2011-10-31 20:19:11 +0000143 struct hlist_head *bucket;
144 int i;
145
146 spin_lock(&tm->lock);
Andrew Mortondf855792013-02-22 16:32:03 -0800147 for (i = 0; i < DM_HASH_SIZE; i++) {
Joe Thornber3241b1d2011-10-31 20:19:11 +0000148 bucket = tm->buckets + i;
Sasha Levinb67bfe02013-02-27 17:06:00 -0800149 hlist_for_each_entry_safe(si, tmp, bucket, hlist)
Joe Thornber3241b1d2011-10-31 20:19:11 +0000150 kfree(si);
151
152 INIT_HLIST_HEAD(bucket);
153 }
154
155 spin_unlock(&tm->lock);
156}
157
158/*----------------------------------------------------------------*/
159
160static struct dm_transaction_manager *dm_tm_create(struct dm_block_manager *bm,
161 struct dm_space_map *sm)
162{
163 int i;
164 struct dm_transaction_manager *tm;
165
166 tm = kmalloc(sizeof(*tm), GFP_KERNEL);
167 if (!tm)
168 return ERR_PTR(-ENOMEM);
169
170 tm->is_clone = 0;
171 tm->real = NULL;
172 tm->bm = bm;
173 tm->sm = sm;
174
175 spin_lock_init(&tm->lock);
Andrew Mortondf855792013-02-22 16:32:03 -0800176 for (i = 0; i < DM_HASH_SIZE; i++)
Joe Thornber3241b1d2011-10-31 20:19:11 +0000177 INIT_HLIST_HEAD(tm->buckets + i);
178
Joe Thornber46460152014-10-06 15:27:26 +0100179 prefetch_init(&tm->prefetches);
180
Joe Thornber3241b1d2011-10-31 20:19:11 +0000181 return tm;
182}
183
184struct dm_transaction_manager *dm_tm_create_non_blocking_clone(struct dm_transaction_manager *real)
185{
186 struct dm_transaction_manager *tm;
187
188 tm = kmalloc(sizeof(*tm), GFP_KERNEL);
189 if (tm) {
190 tm->is_clone = 1;
191 tm->real = real;
192 }
193
194 return tm;
195}
196EXPORT_SYMBOL_GPL(dm_tm_create_non_blocking_clone);
197
198void dm_tm_destroy(struct dm_transaction_manager *tm)
199{
Mike Snitzer25d7cd62012-07-03 12:55:33 +0100200 if (!tm->is_clone)
201 wipe_shadow_table(tm);
202
Joe Thornber3241b1d2011-10-31 20:19:11 +0000203 kfree(tm);
204}
205EXPORT_SYMBOL_GPL(dm_tm_destroy);
206
207int dm_tm_pre_commit(struct dm_transaction_manager *tm)
208{
209 int r;
210
211 if (tm->is_clone)
212 return -EWOULDBLOCK;
213
214 r = dm_sm_commit(tm->sm);
215 if (r < 0)
216 return r;
217
Joe Thornbera9d45392014-03-27 14:13:20 +0000218 return dm_bm_flush(tm->bm);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000219}
220EXPORT_SYMBOL_GPL(dm_tm_pre_commit);
221
222int dm_tm_commit(struct dm_transaction_manager *tm, struct dm_block *root)
223{
224 if (tm->is_clone)
225 return -EWOULDBLOCK;
226
227 wipe_shadow_table(tm);
Joe Thornbera9d45392014-03-27 14:13:20 +0000228 dm_bm_unlock(root);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000229
Joe Thornbera9d45392014-03-27 14:13:20 +0000230 return dm_bm_flush(tm->bm);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000231}
232EXPORT_SYMBOL_GPL(dm_tm_commit);
233
234int dm_tm_new_block(struct dm_transaction_manager *tm,
235 struct dm_block_validator *v,
236 struct dm_block **result)
237{
238 int r;
239 dm_block_t new_block;
240
241 if (tm->is_clone)
242 return -EWOULDBLOCK;
243
244 r = dm_sm_new_block(tm->sm, &new_block);
245 if (r < 0)
246 return r;
247
248 r = dm_bm_write_lock_zero(tm->bm, new_block, v, result);
249 if (r < 0) {
250 dm_sm_dec_block(tm->sm, new_block);
251 return r;
252 }
253
254 /*
255 * New blocks count as shadows in that they don't need to be
256 * shadowed again.
257 */
258 insert_shadow(tm, new_block);
259
260 return 0;
261}
262
263static int __shadow_block(struct dm_transaction_manager *tm, dm_block_t orig,
264 struct dm_block_validator *v,
265 struct dm_block **result)
266{
267 int r;
268 dm_block_t new;
269 struct dm_block *orig_block;
270
271 r = dm_sm_new_block(tm->sm, &new);
272 if (r < 0)
273 return r;
274
275 r = dm_sm_dec_block(tm->sm, orig);
276 if (r < 0)
277 return r;
278
279 r = dm_bm_read_lock(tm->bm, orig, v, &orig_block);
280 if (r < 0)
281 return r;
282
Joe Thornber3c9ad9b2012-07-27 15:08:09 +0100283 /*
284 * It would be tempting to use dm_bm_unlock_move here, but some
285 * code, such as the space maps, keeps using the old data structures
286 * secure in the knowledge they won't be changed until the next
287 * transaction. Using unlock_move would force a synchronous read
288 * since the old block would no longer be in the cache.
289 */
290 r = dm_bm_write_lock_zero(tm->bm, new, v, result);
291 if (r) {
Joe Thornber3241b1d2011-10-31 20:19:11 +0000292 dm_bm_unlock(orig_block);
293 return r;
294 }
295
Joe Thornber3c9ad9b2012-07-27 15:08:09 +0100296 memcpy(dm_block_data(*result), dm_block_data(orig_block),
297 dm_bm_block_size(tm->bm));
298
299 dm_bm_unlock(orig_block);
300 return r;
Joe Thornber3241b1d2011-10-31 20:19:11 +0000301}
302
303int dm_tm_shadow_block(struct dm_transaction_manager *tm, dm_block_t orig,
304 struct dm_block_validator *v, struct dm_block **result,
305 int *inc_children)
306{
307 int r;
308
309 if (tm->is_clone)
310 return -EWOULDBLOCK;
311
312 r = dm_sm_count_is_more_than_one(tm->sm, orig, inc_children);
313 if (r < 0)
314 return r;
315
316 if (is_shadow(tm, orig) && !*inc_children)
317 return dm_bm_write_lock(tm->bm, orig, v, result);
318
319 r = __shadow_block(tm, orig, v, result);
320 if (r < 0)
321 return r;
322 insert_shadow(tm, dm_block_location(*result));
323
324 return r;
325}
Joe Thornbercc8394d2012-06-03 00:30:01 +0100326EXPORT_SYMBOL_GPL(dm_tm_shadow_block);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000327
328int dm_tm_read_lock(struct dm_transaction_manager *tm, dm_block_t b,
329 struct dm_block_validator *v,
330 struct dm_block **blk)
331{
Joe Thornber46460152014-10-06 15:27:26 +0100332 if (tm->is_clone) {
333 int r = dm_bm_read_try_lock(tm->real->bm, b, v, blk);
334
335 if (r == -EWOULDBLOCK)
336 prefetch_add(&tm->real->prefetches, b);
337
338 return r;
339 }
Joe Thornber3241b1d2011-10-31 20:19:11 +0000340
341 return dm_bm_read_lock(tm->bm, b, v, blk);
342}
Joe Thornbercc8394d2012-06-03 00:30:01 +0100343EXPORT_SYMBOL_GPL(dm_tm_read_lock);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000344
Mikulas Patocka4c7da062015-10-22 16:46:59 -0400345void dm_tm_unlock(struct dm_transaction_manager *tm, struct dm_block *b)
Joe Thornber3241b1d2011-10-31 20:19:11 +0000346{
Mikulas Patocka4c7da062015-10-22 16:46:59 -0400347 dm_bm_unlock(b);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000348}
349EXPORT_SYMBOL_GPL(dm_tm_unlock);
350
351void dm_tm_inc(struct dm_transaction_manager *tm, dm_block_t b)
352{
353 /*
354 * The non-blocking clone doesn't support this.
355 */
356 BUG_ON(tm->is_clone);
357
358 dm_sm_inc_block(tm->sm, b);
359}
360EXPORT_SYMBOL_GPL(dm_tm_inc);
361
362void dm_tm_dec(struct dm_transaction_manager *tm, dm_block_t b)
363{
364 /*
365 * The non-blocking clone doesn't support this.
366 */
367 BUG_ON(tm->is_clone);
368
369 dm_sm_dec_block(tm->sm, b);
370}
371EXPORT_SYMBOL_GPL(dm_tm_dec);
372
373int dm_tm_ref(struct dm_transaction_manager *tm, dm_block_t b,
374 uint32_t *result)
375{
376 if (tm->is_clone)
377 return -EWOULDBLOCK;
378
379 return dm_sm_get_count(tm->sm, b, result);
380}
381
382struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm)
383{
384 return tm->bm;
385}
386
Joe Thornber46460152014-10-06 15:27:26 +0100387void dm_tm_issue_prefetches(struct dm_transaction_manager *tm)
388{
389 prefetch_issue(&tm->prefetches, tm->bm);
390}
391EXPORT_SYMBOL_GPL(dm_tm_issue_prefetches);
392
Joe Thornber3241b1d2011-10-31 20:19:11 +0000393/*----------------------------------------------------------------*/
394
395static int dm_tm_create_internal(struct dm_block_manager *bm,
396 dm_block_t sb_location,
Joe Thornber3241b1d2011-10-31 20:19:11 +0000397 struct dm_transaction_manager **tm,
398 struct dm_space_map **sm,
Joe Thornber384ef0e2012-07-27 15:08:09 +0100399 int create,
400 void *sm_root, size_t sm_len)
Joe Thornber3241b1d2011-10-31 20:19:11 +0000401{
402 int r;
Joe Thornber3241b1d2011-10-31 20:19:11 +0000403
Joe Thornber3caf6d72012-07-27 15:07:58 +0100404 *sm = dm_sm_metadata_init();
405 if (IS_ERR(*sm))
406 return PTR_ERR(*sm);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000407
Joe Thornber3caf6d72012-07-27 15:07:58 +0100408 *tm = dm_tm_create(bm, *sm);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000409 if (IS_ERR(*tm)) {
Joe Thornber3caf6d72012-07-27 15:07:58 +0100410 dm_sm_destroy(*sm);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000411 return PTR_ERR(*tm);
412 }
413
414 if (create) {
Joe Thornber3caf6d72012-07-27 15:07:58 +0100415 r = dm_sm_metadata_create(*sm, *tm, dm_bm_nr_blocks(bm),
Joe Thornber3241b1d2011-10-31 20:19:11 +0000416 sb_location);
417 if (r) {
418 DMERR("couldn't create metadata space map");
Joe Thornber384ef0e2012-07-27 15:08:09 +0100419 goto bad;
Joe Thornber3241b1d2011-10-31 20:19:11 +0000420 }
421
Joe Thornber3241b1d2011-10-31 20:19:11 +0000422 } else {
Joe Thornber384ef0e2012-07-27 15:08:09 +0100423 r = dm_sm_metadata_open(*sm, *tm, sm_root, sm_len);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000424 if (r) {
425 DMERR("couldn't open metadata space map");
Joe Thornber384ef0e2012-07-27 15:08:09 +0100426 goto bad;
Joe Thornber3241b1d2011-10-31 20:19:11 +0000427 }
Joe Thornber3241b1d2011-10-31 20:19:11 +0000428 }
429
430 return 0;
431
Joe Thornber384ef0e2012-07-27 15:08:09 +0100432bad:
Joe Thornber3241b1d2011-10-31 20:19:11 +0000433 dm_tm_destroy(*tm);
Joe Thornber384ef0e2012-07-27 15:08:09 +0100434 dm_sm_destroy(*sm);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000435 return r;
436}
437
438int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
Joe Thornber3241b1d2011-10-31 20:19:11 +0000439 struct dm_transaction_manager **tm,
Joe Thornber384ef0e2012-07-27 15:08:09 +0100440 struct dm_space_map **sm)
Joe Thornber3241b1d2011-10-31 20:19:11 +0000441{
Joe Thornber384ef0e2012-07-27 15:08:09 +0100442 return dm_tm_create_internal(bm, sb_location, tm, sm, 1, NULL, 0);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000443}
444EXPORT_SYMBOL_GPL(dm_tm_create_with_sm);
445
446int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location,
Joe Thornber384ef0e2012-07-27 15:08:09 +0100447 void *sm_root, size_t root_len,
Joe Thornber3241b1d2011-10-31 20:19:11 +0000448 struct dm_transaction_manager **tm,
Joe Thornber384ef0e2012-07-27 15:08:09 +0100449 struct dm_space_map **sm)
Joe Thornber3241b1d2011-10-31 20:19:11 +0000450{
Joe Thornber384ef0e2012-07-27 15:08:09 +0100451 return dm_tm_create_internal(bm, sb_location, tm, sm, 0, sm_root, root_len);
Joe Thornber3241b1d2011-10-31 20:19:11 +0000452}
453EXPORT_SYMBOL_GPL(dm_tm_open_with_sm);
454
455/*----------------------------------------------------------------*/