Commit | Line | Data |
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3241b1d3 JT |
1 | /* |
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" | |
3241b1d3 JT |
8 | #include "dm-space-map-disk.h" |
9 | #include "dm-space-map-metadata.h" | |
10 | #include "dm-persistent-data-internal.h" | |
11 | ||
1944ce60 | 12 | #include <linux/export.h> |
4646015d JT |
13 | #include <linux/mutex.h> |
14 | #include <linux/hash.h> | |
3241b1d3 JT |
15 | #include <linux/slab.h> |
16 | #include <linux/device-mapper.h> | |
17 | ||
18 | #define DM_MSG_PREFIX "transaction manager" | |
19 | ||
20 | /*----------------------------------------------------------------*/ | |
21 | ||
4646015d JT |
22 | #define PREFETCH_SIZE 128 |
23 | #define PREFETCH_BITS 7 | |
24 | #define PREFETCH_SENTINEL ((dm_block_t) -1ULL) | |
25 | ||
26 | struct prefetch_set { | |
27 | struct mutex lock; | |
28 | dm_block_t blocks[PREFETCH_SIZE]; | |
29 | }; | |
30 | ||
31 | static unsigned prefetch_hash(dm_block_t b) | |
32 | { | |
33 | return hash_64(b, PREFETCH_BITS); | |
34 | } | |
35 | ||
36 | static 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 | ||
43 | static void prefetch_init(struct prefetch_set *p) | |
44 | { | |
45 | mutex_init(&p->lock); | |
46 | prefetch_wipe(p); | |
47 | } | |
48 | ||
49 | static 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 | ||
60 | static 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 | ||
3241b1d3 JT |
77 | struct 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 | */ | |
df855798 AM |
85 | #define DM_HASH_SIZE 256 |
86 | #define DM_HASH_MASK (DM_HASH_SIZE - 1) | |
3241b1d3 JT |
87 | |
88 | struct 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; | |
df855798 | 96 | struct hlist_head buckets[DM_HASH_SIZE]; |
4646015d JT |
97 | |
98 | struct prefetch_set prefetches; | |
3241b1d3 JT |
99 | }; |
100 | ||
101 | /*----------------------------------------------------------------*/ | |
102 | ||
103 | static int is_shadow(struct dm_transaction_manager *tm, dm_block_t b) | |
104 | { | |
105 | int r = 0; | |
df855798 | 106 | unsigned bucket = dm_hash_block(b, DM_HASH_MASK); |
3241b1d3 | 107 | struct shadow_info *si; |
3241b1d3 JT |
108 | |
109 | spin_lock(&tm->lock); | |
b67bfe0d | 110 | hlist_for_each_entry(si, tm->buckets + bucket, hlist) |
3241b1d3 JT |
111 | 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 | */ | |
124 | static 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; | |
df855798 | 132 | bucket = dm_hash_block(b, DM_HASH_MASK); |
3241b1d3 JT |
133 | spin_lock(&tm->lock); |
134 | hlist_add_head(&si->hlist, tm->buckets + bucket); | |
135 | spin_unlock(&tm->lock); | |
136 | } | |
137 | } | |
138 | ||
139 | static void wipe_shadow_table(struct dm_transaction_manager *tm) | |
140 | { | |
141 | struct shadow_info *si; | |
b67bfe0d | 142 | struct hlist_node *tmp; |
3241b1d3 JT |
143 | struct hlist_head *bucket; |
144 | int i; | |
145 | ||
146 | spin_lock(&tm->lock); | |
df855798 | 147 | for (i = 0; i < DM_HASH_SIZE; i++) { |
3241b1d3 | 148 | bucket = tm->buckets + i; |
b67bfe0d | 149 | hlist_for_each_entry_safe(si, tmp, bucket, hlist) |
3241b1d3 JT |
150 | kfree(si); |
151 | ||
152 | INIT_HLIST_HEAD(bucket); | |
153 | } | |
154 | ||
155 | spin_unlock(&tm->lock); | |
156 | } | |
157 | ||
158 | /*----------------------------------------------------------------*/ | |
159 | ||
160 | static 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); | |
df855798 | 176 | for (i = 0; i < DM_HASH_SIZE; i++) |
3241b1d3 JT |
177 | INIT_HLIST_HEAD(tm->buckets + i); |
178 | ||
4646015d JT |
179 | prefetch_init(&tm->prefetches); |
180 | ||
3241b1d3 JT |
181 | return tm; |
182 | } | |
183 | ||
184 | struct 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 | } | |
196 | EXPORT_SYMBOL_GPL(dm_tm_create_non_blocking_clone); | |
197 | ||
198 | void dm_tm_destroy(struct dm_transaction_manager *tm) | |
199 | { | |
25d7cd6f MS |
200 | if (!tm->is_clone) |
201 | wipe_shadow_table(tm); | |
202 | ||
3241b1d3 JT |
203 | kfree(tm); |
204 | } | |
205 | EXPORT_SYMBOL_GPL(dm_tm_destroy); | |
206 | ||
207 | int 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 | ||
a9d45396 | 218 | return dm_bm_flush(tm->bm); |
3241b1d3 JT |
219 | } |
220 | EXPORT_SYMBOL_GPL(dm_tm_pre_commit); | |
221 | ||
222 | int 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); | |
a9d45396 | 228 | dm_bm_unlock(root); |
3241b1d3 | 229 | |
a9d45396 | 230 | return dm_bm_flush(tm->bm); |
3241b1d3 JT |
231 | } |
232 | EXPORT_SYMBOL_GPL(dm_tm_commit); | |
233 | ||
234 | int 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 | ||
263 | static 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 | ||
3c9ad9bd JT |
283 | /* |
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) { | |
3241b1d3 JT |
292 | dm_bm_unlock(orig_block); |
293 | return r; | |
294 | } | |
295 | ||
3c9ad9bd JT |
296 | 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; | |
3241b1d3 JT |
301 | } |
302 | ||
303 | int 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 | } | |
cc8394d8 | 326 | EXPORT_SYMBOL_GPL(dm_tm_shadow_block); |
3241b1d3 JT |
327 | |
328 | int 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 | { | |
4646015d JT |
332 | 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 | } | |
3241b1d3 JT |
340 | |
341 | return dm_bm_read_lock(tm->bm, b, v, blk); | |
342 | } | |
cc8394d8 | 343 | EXPORT_SYMBOL_GPL(dm_tm_read_lock); |
3241b1d3 JT |
344 | |
345 | int dm_tm_unlock(struct dm_transaction_manager *tm, struct dm_block *b) | |
346 | { | |
347 | return dm_bm_unlock(b); | |
348 | } | |
349 | EXPORT_SYMBOL_GPL(dm_tm_unlock); | |
350 | ||
351 | void 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 | } | |
360 | EXPORT_SYMBOL_GPL(dm_tm_inc); | |
361 | ||
362 | void 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 | } | |
371 | EXPORT_SYMBOL_GPL(dm_tm_dec); | |
372 | ||
373 | int 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 | ||
382 | struct dm_block_manager *dm_tm_get_bm(struct dm_transaction_manager *tm) | |
383 | { | |
384 | return tm->bm; | |
385 | } | |
386 | ||
4646015d JT |
387 | void dm_tm_issue_prefetches(struct dm_transaction_manager *tm) |
388 | { | |
389 | prefetch_issue(&tm->prefetches, tm->bm); | |
390 | } | |
391 | EXPORT_SYMBOL_GPL(dm_tm_issue_prefetches); | |
392 | ||
3241b1d3 JT |
393 | /*----------------------------------------------------------------*/ |
394 | ||
395 | static int dm_tm_create_internal(struct dm_block_manager *bm, | |
396 | dm_block_t sb_location, | |
3241b1d3 JT |
397 | struct dm_transaction_manager **tm, |
398 | struct dm_space_map **sm, | |
384ef0e6 JT |
399 | int create, |
400 | void *sm_root, size_t sm_len) | |
3241b1d3 JT |
401 | { |
402 | int r; | |
3241b1d3 | 403 | |
3caf6d73 JT |
404 | *sm = dm_sm_metadata_init(); |
405 | if (IS_ERR(*sm)) | |
406 | return PTR_ERR(*sm); | |
3241b1d3 | 407 | |
3caf6d73 | 408 | *tm = dm_tm_create(bm, *sm); |
3241b1d3 | 409 | if (IS_ERR(*tm)) { |
3caf6d73 | 410 | dm_sm_destroy(*sm); |
3241b1d3 JT |
411 | return PTR_ERR(*tm); |
412 | } | |
413 | ||
414 | if (create) { | |
3caf6d73 | 415 | r = dm_sm_metadata_create(*sm, *tm, dm_bm_nr_blocks(bm), |
3241b1d3 JT |
416 | sb_location); |
417 | if (r) { | |
418 | DMERR("couldn't create metadata space map"); | |
384ef0e6 | 419 | goto bad; |
3241b1d3 JT |
420 | } |
421 | ||
3241b1d3 | 422 | } else { |
384ef0e6 | 423 | r = dm_sm_metadata_open(*sm, *tm, sm_root, sm_len); |
3241b1d3 JT |
424 | if (r) { |
425 | DMERR("couldn't open metadata space map"); | |
384ef0e6 | 426 | goto bad; |
3241b1d3 | 427 | } |
3241b1d3 JT |
428 | } |
429 | ||
430 | return 0; | |
431 | ||
384ef0e6 | 432 | bad: |
3241b1d3 | 433 | dm_tm_destroy(*tm); |
384ef0e6 | 434 | dm_sm_destroy(*sm); |
3241b1d3 JT |
435 | return r; |
436 | } | |
437 | ||
438 | int dm_tm_create_with_sm(struct dm_block_manager *bm, dm_block_t sb_location, | |
3241b1d3 | 439 | struct dm_transaction_manager **tm, |
384ef0e6 | 440 | struct dm_space_map **sm) |
3241b1d3 | 441 | { |
384ef0e6 | 442 | return dm_tm_create_internal(bm, sb_location, tm, sm, 1, NULL, 0); |
3241b1d3 JT |
443 | } |
444 | EXPORT_SYMBOL_GPL(dm_tm_create_with_sm); | |
445 | ||
446 | int dm_tm_open_with_sm(struct dm_block_manager *bm, dm_block_t sb_location, | |
384ef0e6 | 447 | void *sm_root, size_t root_len, |
3241b1d3 | 448 | struct dm_transaction_manager **tm, |
384ef0e6 | 449 | struct dm_space_map **sm) |
3241b1d3 | 450 | { |
384ef0e6 | 451 | return dm_tm_create_internal(bm, sb_location, tm, sm, 0, sm_root, root_len); |
3241b1d3 JT |
452 | } |
453 | EXPORT_SYMBOL_GPL(dm_tm_open_with_sm); | |
454 | ||
455 | /*----------------------------------------------------------------*/ |