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1 | // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- | |
2 | // vim: ts=8 sw=2 smarttab | |
3 | /* | |
4 | * Ceph - scalable distributed file system | |
5 | * | |
6 | * Copyright (C) 2014 Cloudwatt <libre.licensing@cloudwatt.com> | |
7 | * Copyright (C) 2014 Red Hat <contact@redhat.com> | |
8 | * | |
9 | * Author: Loic Dachary <loic@dachary.org> | |
10 | * | |
11 | * This library is free software; you can redistribute it and/or | |
12 | * modify it under the terms of the GNU Lesser General Public | |
13 | * License as published by the Free Software Foundation; either | |
14 | * version 2.1 of the License, or (at your option) any later version. | |
15 | * | |
16 | */ | |
17 | ||
18 | #include <errno.h> | |
19 | #include <algorithm> | |
20 | ||
21 | #include "include/str_map.h" | |
22 | #include "common/debug.h" | |
23 | #include "crush/CrushWrapper.h" | |
24 | #include "osd/osd_types.h" | |
25 | #include "include/stringify.h" | |
26 | #include "erasure-code/ErasureCodePlugin.h" | |
27 | #include "json_spirit/json_spirit_writer.h" | |
28 | ||
29 | #include "ErasureCodeLrc.h" | |
30 | ||
31 | // re-include our assert to clobber boost's | |
32 | #include "include/assert.h" | |
33 | ||
34 | #define dout_context g_ceph_context | |
35 | #define dout_subsys ceph_subsys_osd | |
36 | #undef dout_prefix | |
37 | #define dout_prefix _prefix(_dout) | |
38 | ||
39 | using namespace std; | |
40 | ||
41 | static ostream& _prefix(std::ostream* _dout) | |
42 | { | |
43 | return *_dout << "ErasureCodeLrc: "; | |
44 | } | |
45 | ||
46 | int ErasureCodeLrc::create_ruleset(const string &name, | |
47 | CrushWrapper &crush, | |
48 | ostream *ss) const | |
49 | { | |
50 | if (crush.rule_exists(name)) { | |
51 | *ss << "rule " << name << " exists"; | |
52 | return -EEXIST; | |
53 | } | |
54 | if (!crush.name_exists(ruleset_root)) { | |
55 | *ss << "root item " << ruleset_root << " does not exist"; | |
56 | return -ENOENT; | |
57 | } | |
58 | int root = crush.get_item_id(ruleset_root); | |
59 | ||
60 | int ruleset = 0; | |
61 | int rno = 0; | |
62 | for (rno = 0; rno < crush.get_max_rules(); rno++) { | |
63 | if (!crush.rule_exists(rno) && !crush.ruleset_exists(rno)) | |
64 | break; | |
65 | } | |
66 | ruleset = rno; | |
67 | ||
68 | int steps = 4 + ruleset_steps.size(); | |
69 | int min_rep = 3; | |
70 | int max_rep = get_chunk_count(); | |
71 | int ret; | |
72 | ret = crush.add_rule(steps, ruleset, pg_pool_t::TYPE_ERASURE, | |
73 | min_rep, max_rep, rno); | |
74 | assert(ret == rno); | |
75 | int step = 0; | |
76 | ||
77 | ret = crush.set_rule_step(rno, step++, CRUSH_RULE_SET_CHOOSELEAF_TRIES, 5, 0); | |
78 | assert(ret == 0); | |
79 | ret = crush.set_rule_step(rno, step++, CRUSH_RULE_SET_CHOOSE_TRIES, 100, 0); | |
80 | assert(ret == 0); | |
81 | ret = crush.set_rule_step(rno, step++, CRUSH_RULE_TAKE, root, 0); | |
82 | assert(ret == 0); | |
83 | // [ [ "choose", "rack", 2 ], | |
84 | // [ "chooseleaf", "host", 5 ] ] | |
85 | for (vector<Step>::const_iterator i = ruleset_steps.begin(); | |
86 | i != ruleset_steps.end(); | |
87 | ++i) { | |
88 | int op = i->op == "chooseleaf" ? | |
89 | CRUSH_RULE_CHOOSELEAF_INDEP : CRUSH_RULE_CHOOSE_INDEP; | |
90 | int type = crush.get_type_id(i->type); | |
91 | if (type < 0) { | |
92 | *ss << "unknown crush type " << i->type; | |
93 | return -EINVAL; | |
94 | } | |
95 | ret = crush.set_rule_step(rno, step++, op, i->n, type); | |
96 | assert(ret == 0); | |
97 | } | |
98 | ret = crush.set_rule_step(rno, step++, CRUSH_RULE_EMIT, 0, 0); | |
99 | assert(ret == 0); | |
100 | crush.set_rule_name(rno, name); | |
101 | return ruleset; | |
102 | } | |
103 | ||
104 | int ErasureCodeLrc::layers_description(const ErasureCodeProfile &profile, | |
105 | json_spirit::mArray *description, | |
106 | ostream *ss) const | |
107 | { | |
108 | if (profile.count("layers") == 0) { | |
109 | *ss << "could not find 'layers' in " << profile << std::endl; | |
110 | return ERROR_LRC_DESCRIPTION; | |
111 | } | |
112 | string str = profile.find("layers")->second; | |
113 | try { | |
114 | json_spirit::mValue json; | |
115 | json_spirit::read_or_throw(str, json); | |
116 | ||
117 | if (json.type() != json_spirit::array_type) { | |
118 | *ss << "layers='" << str | |
119 | << "' must be a JSON array but is of type " | |
120 | << json.type() << " instead" << std::endl; | |
121 | return ERROR_LRC_ARRAY; | |
122 | } | |
123 | *description = json.get_array(); | |
124 | } catch (json_spirit::Error_position &e) { | |
125 | *ss << "failed to parse layers='" << str << "'" | |
126 | << " at line " << e.line_ << ", column " << e.column_ | |
127 | << " : " << e.reason_ << std::endl; | |
128 | return ERROR_LRC_PARSE_JSON; | |
129 | } | |
130 | return 0; | |
131 | } | |
132 | ||
133 | int ErasureCodeLrc::layers_parse(string description_string, | |
134 | json_spirit::mArray description, | |
135 | ostream *ss) | |
136 | { | |
137 | int position = 0; | |
138 | for (vector<json_spirit::mValue>::iterator i = description.begin(); | |
139 | i != description.end(); | |
140 | ++i, position++) { | |
141 | if (i->type() != json_spirit::array_type) { | |
142 | stringstream json_string; | |
143 | json_spirit::write(*i, json_string); | |
144 | *ss << "each element of the array " | |
145 | << description_string << " must be a JSON array but " | |
146 | << json_string.str() << " at position " << position | |
147 | << " is of type " << i->type() << " instead" << std::endl; | |
148 | return ERROR_LRC_ARRAY; | |
149 | } | |
150 | json_spirit::mArray layer_json = i->get_array(); | |
151 | ErasureCodeProfile profile; | |
152 | int index = 0; | |
153 | for (vector<json_spirit::mValue>::iterator j = layer_json.begin(); | |
154 | j != layer_json.end(); | |
155 | ++j, ++index) { | |
156 | if (index == 0) { | |
157 | if (j->type() != json_spirit::str_type) { | |
158 | stringstream element; | |
159 | json_spirit::write(*j, element); | |
160 | *ss << "the first element of the entry " | |
161 | << element.str() << " (first is zero) " | |
162 | << position << " in " << description_string | |
163 | << " is of type " << (*j).type() << " instead of string" << std::endl; | |
164 | return ERROR_LRC_STR; | |
165 | } | |
166 | layers.push_back(Layer(j->get_str())); | |
167 | Layer &layer = layers.back(); | |
168 | layer.chunks_map = j->get_str(); | |
169 | } else if(index == 1) { | |
170 | Layer &layer = layers.back(); | |
171 | if (j->type() != json_spirit::str_type && | |
172 | j->type() != json_spirit::obj_type) { | |
173 | stringstream element; | |
174 | json_spirit::write(*j, element); | |
175 | *ss << "the second element of the entry " | |
176 | << element.str() << " (first is zero) " | |
177 | << position << " in " << description_string | |
178 | << " is of type " << (*j).type() << " instead of string or object" | |
179 | << std::endl; | |
180 | return ERROR_LRC_CONFIG_OPTIONS; | |
181 | } | |
182 | if (j->type() == json_spirit::str_type) { | |
183 | int err = get_json_str_map(j->get_str(), *ss, &layer.profile); | |
184 | if (err) | |
185 | return err; | |
186 | } else if (j->type() == json_spirit::obj_type) { | |
187 | json_spirit::mObject o = j->get_obj(); | |
188 | ||
189 | for (map<string, json_spirit::mValue>::iterator i = o.begin(); | |
190 | i != o.end(); | |
191 | ++i) { | |
192 | layer.profile[i->first] = i->second.get_str(); | |
193 | } | |
194 | } | |
195 | } else { | |
196 | // ignore trailing elements | |
197 | } | |
198 | } | |
199 | } | |
200 | return 0; | |
201 | } | |
202 | ||
203 | int ErasureCodeLrc::layers_init(ostream *ss) | |
204 | { | |
205 | ErasureCodePluginRegistry ®istry = ErasureCodePluginRegistry::instance(); | |
206 | for (unsigned int i = 0; i < layers.size(); i++) { | |
207 | Layer &layer = layers[i]; | |
208 | int position = 0; | |
209 | for(std::string::iterator it = layer.chunks_map.begin(); | |
210 | it != layer.chunks_map.end(); | |
211 | ++it) { | |
212 | if (*it == 'D') | |
213 | layer.data.push_back(position); | |
214 | if (*it == 'c') | |
215 | layer.coding.push_back(position); | |
216 | if (*it == 'c' || *it == 'D') | |
217 | layer.chunks_as_set.insert(position); | |
218 | position++; | |
219 | } | |
220 | layer.chunks = layer.data; | |
221 | layer.chunks.insert(layer.chunks.end(), | |
222 | layer.coding.begin(), layer.coding.end()); | |
223 | if (layer.profile.find("k") == layer.profile.end()) | |
224 | layer.profile["k"] = stringify(layer.data.size()); | |
225 | if (layer.profile.find("m") == layer.profile.end()) | |
226 | layer.profile["m"] = stringify(layer.coding.size()); | |
227 | if (layer.profile.find("plugin") == layer.profile.end()) | |
228 | layer.profile["plugin"] = "jerasure"; | |
229 | if (layer.profile.find("technique") == layer.profile.end()) | |
230 | layer.profile["technique"] = "reed_sol_van"; | |
231 | int err = registry.factory(layer.profile["plugin"], | |
232 | directory, | |
233 | layer.profile, | |
234 | &layer.erasure_code, | |
235 | ss); | |
236 | if (err) | |
237 | return err; | |
238 | } | |
239 | return 0; | |
240 | } | |
241 | ||
242 | int ErasureCodeLrc::layers_sanity_checks(string description_string, | |
243 | ostream *ss) const | |
244 | { | |
245 | int position = 0; | |
246 | ||
247 | if (layers.size() < 1) { | |
248 | *ss << "layers parameter has " << layers.size() | |
249 | << " which is less than the minimum of one. " | |
250 | << description_string << std::endl; | |
251 | return ERROR_LRC_LAYERS_COUNT; | |
252 | } | |
253 | for (vector<Layer>::const_iterator layer = layers.begin(); | |
254 | layer != layers.end(); | |
255 | ++layer) { | |
256 | if (chunk_count != layer->chunks_map.length()) { | |
257 | *ss << "the first element of the array at position " | |
258 | << position << " (starting from zero) " | |
259 | << " is the string '" << layer->chunks_map | |
260 | << " found in the layers parameter " | |
261 | << description_string << ". It is expected to be " | |
262 | << chunk_count << " characters long but is " | |
263 | << layer->chunks_map.length() << " characters long instead " | |
264 | << std::endl; | |
265 | return ERROR_LRC_MAPPING_SIZE; | |
266 | } | |
267 | } | |
268 | return 0; | |
269 | } | |
270 | ||
271 | int ErasureCodeLrc::parse(ErasureCodeProfile &profile, | |
272 | ostream *ss) | |
273 | { | |
274 | int r = ErasureCode::parse(profile, ss); | |
275 | if (r) | |
276 | return r; | |
277 | ||
278 | return parse_ruleset(profile, ss); | |
279 | } | |
280 | ||
281 | const string ErasureCodeLrc::DEFAULT_KML("-1"); | |
282 | ||
283 | int ErasureCodeLrc::parse_kml(ErasureCodeProfile &profile, | |
284 | ostream *ss) | |
285 | { | |
286 | int err = ErasureCode::parse(profile, ss); | |
287 | const int DEFAULT_INT = -1; | |
288 | int k, m, l; | |
289 | err |= to_int("k", profile, &k, DEFAULT_KML, ss); | |
290 | err |= to_int("m", profile, &m, DEFAULT_KML, ss); | |
291 | err |= to_int("l", profile, &l, DEFAULT_KML, ss); | |
292 | ||
293 | if (k == DEFAULT_INT && m == DEFAULT_INT && l == DEFAULT_INT) | |
294 | return err; | |
295 | ||
296 | if ((k != DEFAULT_INT || m != DEFAULT_INT || l != DEFAULT_INT) && | |
297 | (k == DEFAULT_INT || m == DEFAULT_INT || l == DEFAULT_INT)) { | |
298 | *ss << "All of k, m, l must be set or none of them in " | |
299 | << profile << std::endl; | |
300 | return ERROR_LRC_ALL_OR_NOTHING; | |
301 | } | |
302 | ||
303 | const char *generated[] = { "mapping", | |
304 | "layers", | |
305 | "ruleset-steps" }; | |
306 | ||
307 | for (int i = 0; i < 3; i++) { | |
308 | if (profile.count(generated[i])) { | |
309 | *ss << "The " << generated[i] << " parameter cannot be set " | |
310 | << "when k, m, l are set in " << profile << std::endl; | |
311 | return ERROR_LRC_GENERATED; | |
312 | } | |
313 | } | |
314 | ||
315 | if ((k + m) % l) { | |
316 | *ss << "k + m must be a multiple of l in " | |
317 | << profile << std::endl; | |
318 | return ERROR_LRC_K_M_MODULO; | |
319 | } | |
320 | ||
321 | int local_group_count = (k + m) / l; | |
322 | ||
323 | if (k % local_group_count) { | |
324 | *ss << "k must be a multiple of (k + m) / l in " | |
325 | << profile << std::endl; | |
326 | return ERROR_LRC_K_MODULO; | |
327 | } | |
328 | ||
329 | if (m % local_group_count) { | |
330 | *ss << "m must be a multiple of (k + m) / l in " | |
331 | << profile << std::endl; | |
332 | return ERROR_LRC_M_MODULO; | |
333 | } | |
334 | ||
335 | string mapping; | |
336 | for (int i = 0; i < local_group_count; i++) { | |
337 | mapping += string(k / local_group_count, 'D') + | |
338 | string(m / local_group_count, '_') + "_"; | |
339 | } | |
340 | profile["mapping"] = mapping; | |
341 | ||
342 | string layers = "[ "; | |
343 | ||
344 | // global layer | |
345 | layers += " [ \""; | |
346 | for (int i = 0; i < local_group_count; i++) { | |
347 | layers += string(k / local_group_count, 'D') + | |
348 | string(m / local_group_count, 'c') + "_"; | |
349 | } | |
350 | layers += "\", \"\" ],"; | |
351 | ||
352 | // local layers | |
353 | for (int i = 0; i < local_group_count; i++) { | |
354 | layers += " [ \""; | |
355 | for (int j = 0; j < local_group_count; j++) { | |
356 | if (i == j) | |
357 | layers += string(l, 'D') + "c"; | |
358 | else | |
359 | layers += string(l + 1, '_'); | |
360 | } | |
361 | layers += "\", \"\" ],"; | |
362 | } | |
363 | profile["layers"] = layers + "]"; | |
364 | ||
365 | ErasureCodeProfile::const_iterator parameter; | |
366 | string ruleset_locality; | |
367 | parameter = profile.find("ruleset-locality"); | |
368 | if (parameter != profile.end()) | |
369 | ruleset_locality = parameter->second; | |
370 | string ruleset_failure_domain = "host"; | |
371 | parameter = profile.find("ruleset-failure-domain"); | |
372 | if (parameter != profile.end()) | |
373 | ruleset_failure_domain = parameter->second; | |
374 | ||
375 | if (ruleset_locality != "") { | |
376 | ruleset_steps.clear(); | |
377 | ruleset_steps.push_back(Step("choose", ruleset_locality, | |
378 | local_group_count)); | |
379 | ruleset_steps.push_back(Step("chooseleaf", ruleset_failure_domain, | |
380 | l + 1)); | |
381 | } else if (ruleset_failure_domain != "") { | |
382 | ruleset_steps.clear(); | |
383 | ruleset_steps.push_back(Step("chooseleaf", ruleset_failure_domain, 0)); | |
384 | } | |
385 | ||
386 | return err; | |
387 | } | |
388 | ||
389 | int ErasureCodeLrc::parse_ruleset(ErasureCodeProfile &profile, | |
390 | ostream *ss) | |
391 | { | |
392 | int err = 0; | |
393 | err |= to_string("ruleset-root", profile, | |
394 | &ruleset_root, | |
395 | "default", ss); | |
396 | ||
397 | if (profile.count("ruleset-steps") != 0) { | |
398 | ruleset_steps.clear(); | |
399 | string str = profile.find("ruleset-steps")->second; | |
400 | json_spirit::mArray description; | |
401 | try { | |
402 | json_spirit::mValue json; | |
403 | json_spirit::read_or_throw(str, json); | |
404 | ||
405 | if (json.type() != json_spirit::array_type) { | |
406 | *ss << "ruleset-steps='" << str | |
407 | << "' must be a JSON array but is of type " | |
408 | << json.type() << " instead" << std::endl; | |
409 | return ERROR_LRC_ARRAY; | |
410 | } | |
411 | description = json.get_array(); | |
412 | } catch (json_spirit::Error_position &e) { | |
413 | *ss << "failed to parse ruleset-steps='" << str << "'" | |
414 | << " at line " << e.line_ << ", column " << e.column_ | |
415 | << " : " << e.reason_ << std::endl; | |
416 | return ERROR_LRC_PARSE_JSON; | |
417 | } | |
418 | ||
419 | int position = 0; | |
420 | for (vector<json_spirit::mValue>::iterator i = description.begin(); | |
421 | i != description.end(); | |
422 | ++i, position++) { | |
423 | if (i->type() != json_spirit::array_type) { | |
424 | stringstream json_string; | |
425 | json_spirit::write(*i, json_string); | |
426 | *ss << "element of the array " | |
427 | << str << " must be a JSON array but " | |
428 | << json_string.str() << " at position " << position | |
429 | << " is of type " << i->type() << " instead" << std::endl; | |
430 | return ERROR_LRC_ARRAY; | |
431 | } | |
432 | int r = parse_ruleset_step(str, i->get_array(), ss); | |
433 | if (r) | |
434 | return r; | |
435 | } | |
436 | } | |
437 | return 0; | |
438 | } | |
439 | ||
440 | int ErasureCodeLrc::parse_ruleset_step(string description_string, | |
441 | json_spirit::mArray description, | |
442 | ostream *ss) | |
443 | { | |
444 | stringstream json_string; | |
445 | json_spirit::write(description, json_string); | |
446 | string op; | |
447 | string type; | |
448 | int n = 0; | |
449 | int position = 0; | |
450 | for (vector<json_spirit::mValue>::iterator i = description.begin(); | |
451 | i != description.end(); | |
452 | ++i, position++) { | |
453 | if ((position == 0 || position == 1) && | |
454 | i->type() != json_spirit::str_type) { | |
455 | *ss << "element " << position << " of the array " | |
456 | << json_string.str() << " found in " << description_string | |
457 | << " must be a JSON string but is of type " | |
458 | << i->type() << " instead" << std::endl; | |
459 | return position == 0 ? ERROR_LRC_RULESET_OP : ERROR_LRC_RULESET_TYPE; | |
460 | } | |
461 | if (position == 2 && i->type() != json_spirit::int_type) { | |
462 | *ss << "element " << position << " of the array " | |
463 | << json_string.str() << " found in " << description_string | |
464 | << " must be a JSON int but is of type " | |
465 | << i->type() << " instead" << std::endl; | |
466 | return ERROR_LRC_RULESET_N; | |
467 | } | |
468 | ||
469 | if (position == 0) | |
470 | op = i->get_str(); | |
471 | if (position == 1) | |
472 | type = i->get_str(); | |
473 | if (position == 2) | |
474 | n = i->get_int(); | |
475 | } | |
476 | ruleset_steps.push_back(Step(op, type, n)); | |
477 | return 0; | |
478 | } | |
479 | ||
480 | int ErasureCodeLrc::init(ErasureCodeProfile &profile, | |
481 | ostream *ss) | |
482 | { | |
483 | int r; | |
484 | ||
485 | r = parse_kml(profile, ss); | |
486 | if (r) | |
487 | return r; | |
488 | ||
489 | r = parse(profile, ss); | |
490 | if (r) | |
491 | return r; | |
492 | ||
493 | json_spirit::mArray description; | |
494 | r = layers_description(profile, &description, ss); | |
495 | if (r) | |
496 | return r; | |
497 | ||
498 | string description_string = profile.find("layers")->second; | |
499 | ||
500 | dout(10) << "init(" << description_string << ")" << dendl; | |
501 | ||
502 | r = layers_parse(description_string, description, ss); | |
503 | if (r) | |
504 | return r; | |
505 | ||
506 | r = layers_init(ss); | |
507 | if (r) | |
508 | return r; | |
509 | ||
510 | if (profile.count("mapping") == 0) { | |
511 | *ss << "the 'mapping' profile is missing from " << profile; | |
512 | return ERROR_LRC_MAPPING; | |
513 | } | |
514 | string mapping = profile.find("mapping")->second; | |
515 | data_chunk_count = 0; | |
516 | for(std::string::iterator it = mapping.begin(); it != mapping.end(); ++it) { | |
517 | if (*it == 'D') | |
518 | data_chunk_count++; | |
519 | } | |
520 | chunk_count = mapping.length(); | |
521 | ||
522 | r = layers_sanity_checks(description_string, ss); | |
523 | if (r) | |
524 | return r; | |
525 | ||
526 | // | |
527 | // When initialized with kml, the profile parameters | |
528 | // that were generated should not be stored because | |
529 | // they would otherwise be exposed to the caller. | |
530 | // | |
531 | if (profile.find("l") != profile.end() && | |
532 | profile.find("l")->second != DEFAULT_KML) { | |
533 | profile.erase("mapping"); | |
534 | profile.erase("layers"); | |
535 | } | |
536 | ErasureCode::init(profile, ss); | |
537 | return 0; | |
538 | } | |
539 | ||
540 | set<int> ErasureCodeLrc::get_erasures(const set<int> &want, | |
541 | const set<int> &available) const | |
542 | { | |
543 | set<int> result; | |
544 | set_difference(want.begin(), want.end(), | |
545 | available.begin(), available.end(), | |
546 | inserter(result, result.end())); | |
547 | return result; | |
548 | } | |
549 | ||
550 | unsigned int ErasureCodeLrc::get_chunk_size(unsigned int object_size) const | |
551 | { | |
552 | return layers.front().erasure_code->get_chunk_size(object_size); | |
553 | } | |
554 | ||
555 | void p(const set<int> &s) { cerr << s; } // for gdb | |
556 | ||
557 | int ErasureCodeLrc::minimum_to_decode(const set<int> &want_to_read, | |
558 | const set<int> &available_chunks, | |
559 | set<int> *minimum) | |
560 | { | |
561 | dout(20) << __func__ << " want_to_read " << want_to_read | |
562 | << " available_chunks " << available_chunks << dendl; | |
563 | { | |
564 | set<int> erasures_total; | |
565 | set<int> erasures_not_recovered; | |
566 | set<int> erasures_want; | |
567 | for (unsigned int i = 0; i < get_chunk_count(); ++i) { | |
568 | if (available_chunks.count(i) == 0) { | |
569 | erasures_total.insert(i); | |
570 | erasures_not_recovered.insert(i); | |
571 | if (want_to_read.count(i) != 0) | |
572 | erasures_want.insert(i); | |
573 | } | |
574 | } | |
575 | ||
576 | // | |
577 | // Case 1: | |
578 | // | |
579 | // When no chunk is missing there is no need to read more than what | |
580 | // is wanted. | |
581 | // | |
582 | if (erasures_want.empty()) { | |
583 | *minimum = want_to_read; | |
584 | dout(20) << __func__ << " minimum == want_to_read == " | |
585 | << want_to_read << dendl; | |
586 | return 0; | |
587 | } | |
588 | ||
589 | // | |
590 | // Case 2: | |
591 | // | |
592 | // Try to recover erasures with as few chunks as possible. | |
593 | // | |
594 | for (vector<Layer>::reverse_iterator i = layers.rbegin(); | |
595 | i != layers.rend(); | |
596 | ++i) { | |
597 | // | |
598 | // If this layer has no chunk that we want, skip it. | |
599 | // | |
600 | set<int> layer_want; | |
601 | set_intersection(want_to_read.begin(), want_to_read.end(), | |
602 | i->chunks_as_set.begin(), i->chunks_as_set.end(), | |
603 | inserter(layer_want, layer_want.end())); | |
604 | if (layer_want.empty()) | |
605 | continue; | |
606 | // | |
607 | // Are some of the chunks we want missing ? | |
608 | // | |
609 | set<int> layer_erasures; | |
610 | set_intersection(layer_want.begin(), layer_want.end(), | |
611 | erasures_want.begin(), erasures_want.end(), | |
612 | inserter(layer_erasures, layer_erasures.end())); | |
613 | set<int> layer_minimum; | |
614 | if (layer_erasures.empty()) { | |
615 | // | |
616 | // The chunks we want are available, this is the minimum we need | |
617 | // to read. | |
618 | // | |
619 | layer_minimum = layer_want; | |
620 | } else { | |
621 | set<int> erasures; | |
622 | set_intersection(i->chunks_as_set.begin(), i->chunks_as_set.end(), | |
623 | erasures_not_recovered.begin(), erasures_not_recovered.end(), | |
624 | inserter(erasures, erasures.end())); | |
625 | ||
626 | if (erasures.size() > i->erasure_code->get_coding_chunk_count()) { | |
627 | // | |
628 | // There are too many erasures for this layer to recover: skip | |
629 | // it and hope that an upper layer will be do better. | |
630 | // | |
631 | continue; | |
632 | } else { | |
633 | // | |
634 | // Get all available chunks in that layer to recover the | |
635 | // missing one(s). | |
636 | // | |
637 | set_difference(i->chunks_as_set.begin(), i->chunks_as_set.end(), | |
638 | erasures_not_recovered.begin(), erasures_not_recovered.end(), | |
639 | inserter(layer_minimum, layer_minimum.end())); | |
640 | // | |
641 | // Chunks recovered by this layer are removed from the list of | |
642 | // erasures so that upper levels do not attempt to recover | |
643 | // them. | |
644 | // | |
645 | for (set<int>::const_iterator j = erasures.begin(); | |
646 | j != erasures.end(); | |
647 | ++j) { | |
648 | erasures_not_recovered.erase(*j); | |
649 | if (erasures_want.count(*j)) | |
650 | erasures_want.erase(*j); | |
651 | } | |
652 | } | |
653 | } | |
654 | minimum->insert(layer_minimum.begin(), layer_minimum.end()); | |
655 | } | |
656 | if (erasures_want.empty()) { | |
657 | minimum->insert(want_to_read.begin(), want_to_read.end()); | |
658 | for (set<int>::const_iterator i = erasures_total.begin(); | |
659 | i != erasures_total.end(); | |
660 | ++i) { | |
661 | if (minimum->count(*i)) | |
662 | minimum->erase(*i); | |
663 | } | |
664 | dout(20) << __func__ << " minimum = " << *minimum << dendl; | |
665 | return 0; | |
666 | } | |
667 | } | |
668 | ||
669 | { | |
670 | // | |
671 | // Case 3: | |
672 | // | |
673 | // The previous strategy failed to recover from all erasures. | |
674 | // | |
675 | // Try to recover as many chunks as possible, even from layers | |
676 | // that do not contain chunks that we want, in the hope that it | |
677 | // will help the upper layers. | |
678 | // | |
679 | set<int> erasures_total; | |
680 | for (unsigned int i = 0; i < get_chunk_count(); ++i) { | |
681 | if (available_chunks.count(i) == 0) | |
682 | erasures_total.insert(i); | |
683 | } | |
684 | ||
685 | for (vector<Layer>::reverse_iterator i = layers.rbegin(); | |
686 | i != layers.rend(); | |
687 | ++i) { | |
688 | set<int> layer_erasures; | |
689 | set_intersection(i->chunks_as_set.begin(), i->chunks_as_set.end(), | |
690 | erasures_total.begin(), erasures_total.end(), | |
691 | inserter(layer_erasures, layer_erasures.end())); | |
692 | // | |
693 | // If this layer has no erasure, skip it | |
694 | // | |
695 | if (layer_erasures.empty()) | |
696 | continue; | |
697 | ||
698 | if (layer_erasures.size() > 0 && | |
699 | layer_erasures.size() <= i->erasure_code->get_coding_chunk_count()) { | |
700 | // | |
701 | // chunks recovered by this layer are removed from the list of | |
702 | // erasures so that upper levels know they can rely on their | |
703 | // availability | |
704 | // | |
705 | for (set<int>::const_iterator j = layer_erasures.begin(); | |
706 | j != layer_erasures.end(); | |
707 | ++j) { | |
708 | erasures_total.erase(*j); | |
709 | } | |
710 | } | |
711 | } | |
712 | if (erasures_total.empty()) { | |
713 | // | |
714 | // Do not try to be smart about what chunks are necessary to | |
715 | // recover, use all available chunks. | |
716 | // | |
717 | *minimum = available_chunks; | |
718 | dout(20) << __func__ << " minimum == available_chunks == " | |
719 | << available_chunks << dendl; | |
720 | return 0; | |
721 | } | |
722 | } | |
723 | ||
724 | derr << __func__ << " not enough chunks in " << available_chunks | |
725 | << " to read " << want_to_read << dendl; | |
726 | return -EIO; | |
727 | } | |
728 | ||
729 | int ErasureCodeLrc::encode_chunks(const set<int> &want_to_encode, | |
730 | map<int, bufferlist> *encoded) | |
731 | { | |
732 | unsigned int top = layers.size(); | |
733 | for (vector<Layer>::reverse_iterator i = layers.rbegin(); | |
734 | i != layers.rend(); | |
735 | ++i) { | |
736 | --top; | |
737 | if (includes(i->chunks_as_set.begin(), i->chunks_as_set.end(), | |
738 | want_to_encode.begin(), want_to_encode.end())) | |
739 | break; | |
740 | } | |
741 | ||
742 | for (unsigned int i = top; i < layers.size(); ++i) { | |
743 | const Layer &layer = layers[i]; | |
744 | set<int> layer_want_to_encode; | |
745 | map<int, bufferlist> layer_encoded; | |
746 | int j = 0; | |
747 | for (vector<int>::const_iterator c = layer.chunks.begin(); | |
748 | c != layer.chunks.end(); | |
749 | ++c) { | |
750 | layer_encoded[j] = (*encoded)[*c]; | |
751 | if (want_to_encode.find(*c) != want_to_encode.end()) | |
752 | layer_want_to_encode.insert(j); | |
753 | j++; | |
754 | } | |
755 | int err = layer.erasure_code->encode_chunks(layer_want_to_encode, | |
756 | &layer_encoded); | |
757 | if (err) { | |
758 | derr << __func__ << " layer " << layer.chunks_map | |
759 | << " failed with " << err << " trying to encode " | |
760 | << layer_want_to_encode << dendl; | |
761 | return err; | |
762 | } | |
763 | } | |
764 | return 0; | |
765 | } | |
766 | ||
767 | int ErasureCodeLrc::decode_chunks(const set<int> &want_to_read, | |
768 | const map<int, bufferlist> &chunks, | |
769 | map<int, bufferlist> *decoded) | |
770 | { | |
771 | set<int> available_chunks; | |
772 | set<int> erasures; | |
773 | for (unsigned int i = 0; i < get_chunk_count(); ++i) { | |
774 | if (chunks.count(i) != 0) | |
775 | available_chunks.insert(i); | |
776 | else | |
777 | erasures.insert(i); | |
778 | } | |
779 | ||
780 | set<int> want_to_read_erasures; | |
781 | ||
782 | for (vector<Layer>::reverse_iterator layer = layers.rbegin(); | |
783 | layer != layers.rend(); | |
784 | ++layer) { | |
785 | set<int> layer_erasures; | |
786 | set_intersection(layer->chunks_as_set.begin(), layer->chunks_as_set.end(), | |
787 | erasures.begin(), erasures.end(), | |
788 | inserter(layer_erasures, layer_erasures.end())); | |
789 | ||
790 | if (layer_erasures.size() > | |
791 | layer->erasure_code->get_coding_chunk_count()) { | |
792 | // skip because there are too many erasures for this layer to recover | |
793 | } else if(layer_erasures.size() == 0) { | |
794 | // skip because all chunks are already available | |
795 | } else { | |
796 | set<int> layer_want_to_read; | |
797 | map<int, bufferlist> layer_chunks; | |
798 | map<int, bufferlist> layer_decoded; | |
799 | int j = 0; | |
800 | for (vector<int>::const_iterator c = layer->chunks.begin(); | |
801 | c != layer->chunks.end(); | |
802 | ++c) { | |
803 | // | |
804 | // Pick chunks from *decoded* instead of *chunks* to re-use | |
805 | // chunks recovered by previous layers. In other words | |
806 | // *chunks* does not change but *decoded* gradually improves | |
807 | // as more layers recover from erasures. | |
808 | // | |
809 | if (erasures.count(*c) == 0) | |
810 | layer_chunks[j] = (*decoded)[*c]; | |
811 | if (want_to_read.count(*c) != 0) | |
812 | layer_want_to_read.insert(j); | |
813 | layer_decoded[j] = (*decoded)[*c]; | |
814 | ++j; | |
815 | } | |
816 | int err = layer->erasure_code->decode_chunks(layer_want_to_read, | |
817 | layer_chunks, | |
818 | &layer_decoded); | |
819 | if (err) { | |
820 | derr << __func__ << " layer " << layer->chunks_map | |
821 | << " failed with " << err << " trying to decode " | |
822 | << layer_want_to_read << " with " << available_chunks << dendl; | |
823 | return err; | |
824 | } | |
825 | j = 0; | |
826 | for (vector<int>::const_iterator c = layer->chunks.begin(); | |
827 | c != layer->chunks.end(); | |
828 | ++c) { | |
829 | (*decoded)[*c] = layer_decoded[j]; | |
830 | ++j; | |
831 | if (erasures.count(*c) != 0) | |
832 | erasures.erase(*c); | |
833 | } | |
834 | want_to_read_erasures.clear(); | |
835 | set_intersection(erasures.begin(), erasures.end(), | |
836 | want_to_read.begin(), want_to_read.end(), | |
837 | inserter(want_to_read_erasures, want_to_read_erasures.end())); | |
838 | if (want_to_read_erasures.size() == 0) | |
839 | break; | |
840 | } | |
841 | } | |
842 | ||
843 | if (want_to_read_erasures.size() > 0) { | |
844 | derr << __func__ << " want to read " << want_to_read | |
845 | << " with available_chunks = " << available_chunks | |
846 | << " end up being unable to read " << want_to_read_erasures << dendl; | |
847 | return -EIO; | |
848 | } else { | |
849 | return 0; | |
850 | } | |
851 | } |