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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) 2004-2006 Sage Weil <sage@newdream.net> | |
7 | * | |
8 | * This is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License version 2.1, as published by the Free Software | |
11 | * Foundation. See file COPYING. | |
12 | * | |
13 | */ | |
14 | ||
15 | #ifndef CEPH_HASHINDEX_H | |
16 | #define CEPH_HASHINDEX_H | |
17 | ||
18 | #include "include/buffer_fwd.h" | |
19 | #include "include/encoding.h" | |
20 | #include "LFNIndex.h" | |
21 | ||
22 | extern string reverse_hexdigit_bits_string(string l); | |
23 | ||
24 | /** | |
25 | * Implements collection prehashing. | |
26 | * | |
27 | * @verbatim | |
28 | * (root) - 0 - 0 | |
29 | * - 1 | |
30 | * - E | |
31 | * - 1 | |
32 | * - 2 - D - 0 | |
33 | * . | |
34 | * . | |
35 | * . | |
36 | * - F - 0 | |
37 | * @endverbatim | |
38 | * | |
39 | * A file is located at the longest existing directory from the root | |
40 | * given by the hex characters in the hash beginning with the least | |
41 | * significant. | |
42 | * | |
43 | * ex: ghobject_t("object", CEPH_NO_SNAP, 0xA4CEE0D2) | |
44 | * would be located in (root)/2/D/0/ | |
45 | * | |
224ce89b WB |
46 | * Subdirectories are created when the number of objects in a |
47 | * directory exceed 16 * (abs(merge_threshhold)) * split_multiplier + | |
48 | * split_rand_factor). The number of objects in a directory is encoded | |
49 | * as subdir_info_s in an xattr on the directory. | |
7c673cae FG |
50 | */ |
51 | class HashIndex : public LFNIndex { | |
52 | private: | |
53 | /// Attribute name for storing subdir info @see subdir_info_s | |
54 | static const string SUBDIR_ATTR; | |
224ce89b WB |
55 | /// Attribute name for storing index-wide settings |
56 | static const string SETTINGS_ATTR; | |
7c673cae FG |
57 | /// Attribute name for storing in progress op tag |
58 | static const string IN_PROGRESS_OP_TAG; | |
59 | /// Size (bits) in object hash | |
60 | static const int PATH_HASH_LEN = 32; | |
61 | /// Max length of hashed path | |
62 | static const int MAX_HASH_LEVEL = (PATH_HASH_LEN/4); | |
63 | ||
64 | /** | |
65 | * Merges occur when the number of object drops below | |
66 | * merge_threshold and splits occur when the number of objects | |
224ce89b WB |
67 | * exceeds: |
68 | * | |
69 | * 16 * (abs(merge_threshold) * split_multiplier + split_rand_factor) | |
70 | * | |
71 | * Please note if merge_threshold is less than zero, it will never | |
72 | * do merging | |
7c673cae FG |
73 | */ |
74 | int merge_threshold; | |
75 | int split_multiplier; | |
76 | ||
77 | /// Encodes current subdir state for determining when to split/merge. | |
78 | struct subdir_info_s { | |
79 | uint64_t objs; ///< Objects in subdir. | |
80 | uint32_t subdirs; ///< Subdirs in subdir. | |
81 | uint32_t hash_level; ///< Hashlevel of subdir. | |
82 | ||
83 | subdir_info_s() : objs(0), subdirs(0), hash_level(0) {} | |
84 | ||
85 | void encode(bufferlist &bl) const | |
86 | { | |
87 | __u8 v = 1; | |
88 | ::encode(v, bl); | |
89 | ::encode(objs, bl); | |
90 | ::encode(subdirs, bl); | |
91 | ::encode(hash_level, bl); | |
92 | } | |
93 | ||
94 | void decode(bufferlist::iterator &bl) | |
95 | { | |
96 | __u8 v; | |
97 | ::decode(v, bl); | |
98 | assert(v == 1); | |
99 | ::decode(objs, bl); | |
100 | ::decode(subdirs, bl); | |
101 | ::decode(hash_level, bl); | |
102 | } | |
103 | }; | |
104 | ||
224ce89b WB |
105 | struct settings_s { |
106 | uint32_t split_rand_factor; ///< random factor added to split threshold (only on root of collection) | |
107 | settings_s() : split_rand_factor(0) {} | |
108 | void encode(bufferlist &bl) const | |
109 | { | |
110 | __u8 v = 1; | |
111 | ::encode(v, bl); | |
112 | ::encode(split_rand_factor, bl); | |
113 | } | |
114 | void decode(bufferlist::iterator &bl) | |
115 | { | |
116 | __u8 v; | |
117 | ::decode(v, bl); | |
118 | ::decode(split_rand_factor, bl); | |
119 | } | |
120 | } settings; | |
121 | ||
7c673cae FG |
122 | /// Encodes in progress split or merge |
123 | struct InProgressOp { | |
124 | static const int SPLIT = 0; | |
125 | static const int MERGE = 1; | |
126 | static const int COL_SPLIT = 2; | |
127 | int op; | |
128 | vector<string> path; | |
129 | ||
130 | InProgressOp(int op, const vector<string> &path) | |
131 | : op(op), path(path) {} | |
132 | ||
133 | explicit InProgressOp(bufferlist::iterator &bl) { | |
134 | decode(bl); | |
135 | } | |
136 | ||
137 | bool is_split() const { return op == SPLIT; } | |
138 | bool is_col_split() const { return op == COL_SPLIT; } | |
139 | bool is_merge() const { return op == MERGE; } | |
140 | ||
141 | void encode(bufferlist &bl) const { | |
142 | __u8 v = 1; | |
143 | ::encode(v, bl); | |
144 | ::encode(op, bl); | |
145 | ::encode(path, bl); | |
146 | } | |
147 | ||
148 | void decode(bufferlist::iterator &bl) { | |
149 | __u8 v; | |
150 | ::decode(v, bl); | |
151 | assert(v == 1); | |
152 | ::decode(op, bl); | |
153 | ::decode(path, bl); | |
154 | } | |
155 | }; | |
156 | ||
157 | ||
158 | public: | |
159 | /// Constructor. | |
160 | HashIndex( | |
161 | CephContext* cct, | |
162 | coll_t collection, ///< [in] Collection | |
163 | const char *base_path, ///< [in] Path to the index root. | |
164 | int merge_at, ///< [in] Merge threshhold. | |
165 | int split_multiple, ///< [in] Split threshhold. | |
166 | uint32_t index_version,///< [in] Index version | |
167 | double retry_probability=0) ///< [in] retry probability | |
168 | : LFNIndex(cct, collection, base_path, index_version, retry_probability), | |
169 | merge_threshold(merge_at), | |
224ce89b WB |
170 | split_multiplier(split_multiple) |
171 | {} | |
172 | ||
173 | int read_settings() override; | |
7c673cae FG |
174 | |
175 | /// @see CollectionIndex | |
176 | uint32_t collection_version() override { return index_version; } | |
177 | ||
178 | /// @see CollectionIndex | |
179 | int cleanup() override; | |
180 | ||
181 | /// @see CollectionIndex | |
182 | int prep_delete() override; | |
183 | ||
184 | /// @see CollectionIndex | |
185 | int _split( | |
186 | uint32_t match, | |
187 | uint32_t bits, | |
188 | CollectionIndex* dest | |
189 | ) override; | |
190 | ||
191 | /// @see CollectionIndex | |
192 | int apply_layout_settings() override; | |
193 | ||
194 | protected: | |
195 | int _init() override; | |
196 | ||
197 | int _created( | |
198 | const vector<string> &path, | |
199 | const ghobject_t &oid, | |
200 | const string &mangled_name | |
201 | ) override; | |
202 | int _remove( | |
203 | const vector<string> &path, | |
204 | const ghobject_t &oid, | |
205 | const string &mangled_name | |
206 | ) override; | |
207 | int _lookup( | |
208 | const ghobject_t &oid, | |
209 | vector<string> *path, | |
210 | string *mangled_name, | |
211 | int *hardlink | |
212 | ) override; | |
213 | ||
214 | /** | |
215 | * Pre-hash the collection to create folders according to the expected number | |
216 | * of objects in this collection. | |
217 | */ | |
218 | int _pre_hash_collection( | |
219 | uint32_t pg_num, | |
220 | uint64_t expected_num_objs | |
221 | ) override; | |
222 | ||
223 | int _collection_list_partial( | |
224 | const ghobject_t &start, | |
225 | const ghobject_t &end, | |
226 | int max_count, | |
227 | vector<ghobject_t> *ls, | |
228 | ghobject_t *next | |
229 | ) override; | |
230 | private: | |
231 | /// Internal recursively remove path and its subdirs | |
232 | int _recursive_remove( | |
233 | const vector<string> &path, ///< [in] path to remove | |
234 | bool top ///< [in] internal tracking of first caller | |
235 | ); /// @return Error Code, 0 on success | |
236 | /// Recursively remove path and its subdirs | |
237 | int recursive_remove( | |
238 | const vector<string> &path ///< [in] path to remove | |
239 | ); /// @return Error Code, 0 on success | |
240 | /// Tag root directory at beginning of col_split | |
241 | int start_col_split( | |
242 | const vector<string> &path ///< [in] path to split | |
243 | ); ///< @return Error Code, 0 on success | |
244 | /// Tag root directory at beginning of split | |
245 | int start_split( | |
246 | const vector<string> &path ///< [in] path to split | |
247 | ); ///< @return Error Code, 0 on success | |
248 | /// Tag root directory at beginning of split | |
249 | int start_merge( | |
250 | const vector<string> &path ///< [in] path to merge | |
251 | ); ///< @return Error Code, 0 on success | |
252 | /// Remove tag at end of split or merge | |
253 | int end_split_or_merge( | |
254 | const vector<string> &path ///< [in] path to split or merged | |
255 | ); ///< @return Error Code, 0 on success | |
256 | /// Gets info from the xattr on the subdir represented by path | |
257 | int get_info( | |
258 | const vector<string> &path, ///< [in] Path from which to read attribute. | |
259 | subdir_info_s *info ///< [out] Attribute value | |
260 | ); /// @return Error Code, 0 on success | |
261 | ||
262 | /// Sets info to the xattr on the subdir represented by path | |
263 | int set_info( | |
264 | const vector<string> &path, ///< [in] Path on which to set attribute. | |
265 | const subdir_info_s &info ///< [in] Value to set | |
266 | ); /// @return Error Code, 0 on success | |
267 | ||
268 | /// Encapsulates logic for when to split. | |
269 | bool must_merge( | |
270 | const subdir_info_s &info ///< [in] Info to check | |
271 | ); /// @return True if info must be merged, False otherwise | |
272 | ||
273 | /// Encapsulates logic for when to merge. | |
274 | bool must_split( | |
275 | const subdir_info_s &info ///< [in] Info to check | |
276 | ); /// @return True if info must be split, False otherwise | |
277 | ||
278 | /// Initiates merge | |
279 | int initiate_merge( | |
280 | const vector<string> &path, ///< [in] Subdir to merge | |
281 | subdir_info_s info ///< [in] Info attached to path | |
282 | ); /// @return Error Code, 0 on success | |
283 | ||
284 | /// Completes merge | |
285 | int complete_merge( | |
286 | const vector<string> &path, ///< [in] Subdir to merge | |
287 | subdir_info_s info ///< [in] Info attached to path | |
288 | ); /// @return Error Code, 0 on success | |
289 | ||
290 | /// Resets attr to match actual subdir contents | |
291 | int reset_attr( | |
292 | const vector<string> &path ///< [in] path to cleanup | |
293 | ); | |
294 | ||
295 | /// Initiate Split | |
296 | int initiate_split( | |
297 | const vector<string> &path, ///< [in] Subdir to split | |
298 | subdir_info_s info ///< [in] Info attached to path | |
299 | ); /// @return Error Code, 0 on success | |
300 | ||
301 | /// Completes Split | |
302 | int complete_split( | |
303 | const vector<string> &path, ///< [in] Subdir to split | |
304 | subdir_info_s info ///< [in] Info attached to path | |
305 | ); /// @return Error Code, 0 on success | |
306 | ||
307 | /// Determine path components from hoid hash | |
308 | void get_path_components( | |
309 | const ghobject_t &oid, ///< [in] Object for which to get path components | |
310 | vector<string> *path ///< [out] Path components for hoid. | |
311 | ); | |
312 | ||
313 | /// Pre-hash and split folders to avoid runtime splitting | |
314 | /// according to the given expected object number. | |
315 | int pre_split_folder(uint32_t pg_num, uint64_t expected_num_objs); | |
316 | ||
317 | /// Initialize the folder (dir info) with the given hash | |
318 | /// level and number of its subdirs. | |
319 | int init_split_folder(vector<string> &path, uint32_t hash_level); | |
320 | ||
321 | /// do collection split for path | |
322 | static int col_split_level( | |
323 | HashIndex &from, ///< [in] from index | |
324 | HashIndex &dest, ///< [in] to index | |
325 | const vector<string> &path, ///< [in] path to split | |
326 | uint32_t bits, ///< [in] num bits to match | |
327 | uint32_t match, ///< [in] bits to match | |
328 | unsigned *mkdirred ///< [in,out] path[:mkdirred] has been mkdirred | |
329 | ); | |
330 | ||
331 | ||
332 | /** | |
333 | * Get string representation of ghobject_t/hash | |
334 | * | |
335 | * e.g: 0x01234567 -> "76543210" | |
336 | */ | |
337 | static string get_path_str( | |
338 | const ghobject_t &oid ///< [in] Object to get hash string for | |
339 | ); ///< @return Hash string for hoid. | |
340 | ||
341 | /// Get string from hash, @see get_path_str | |
342 | static string get_hash_str( | |
343 | uint32_t hash ///< [in] Hash to convert to a string. | |
344 | ); ///< @return String representation of hash | |
345 | ||
346 | /// Get hash from hash prefix string e.g. "FFFFAB" -> 0xFFFFAB00 | |
347 | static uint32_t hash_prefix_to_hash( | |
348 | string prefix ///< [in] string to convert | |
349 | ); ///< @return Hash | |
350 | ||
351 | /// Get hash mod from path | |
352 | static void path_to_hobject_hash_prefix( | |
353 | const vector<string> &path,///< [in] path to convert | |
354 | uint32_t *bits, ///< [out] bits | |
355 | uint32_t *hash ///< [out] hash | |
356 | ) { | |
357 | string hash_str; | |
358 | for (vector<string>::const_iterator i = path.begin(); | |
359 | i != path.end(); | |
360 | ++i) { | |
361 | hash_str.push_back(*i->begin()); | |
362 | } | |
363 | uint32_t rev_hash = hash_prefix_to_hash(hash_str); | |
364 | if (hash) | |
365 | *hash = rev_hash; | |
366 | if (bits) | |
367 | *bits = path.size() * 4; | |
368 | } | |
369 | ||
370 | /// Calculate the number of bits. | |
371 | static int calc_num_bits(uint64_t n) { | |
372 | int ret = 0; | |
373 | while (n > 0) { | |
374 | n = n >> 1; | |
375 | ret++; | |
376 | } | |
377 | return ret; | |
378 | } | |
379 | ||
380 | /// Convert a number to hex string (upper case). | |
381 | static string to_hex(int n) { | |
382 | assert(n >= 0 && n < 16); | |
383 | char c = (n <= 9 ? ('0' + n) : ('A' + n - 10)); | |
384 | string str; | |
385 | str.append(1, c); | |
386 | return str; | |
387 | } | |
388 | ||
389 | struct CmpPairBitwise { | |
390 | bool operator()(const pair<string, ghobject_t>& l, | |
391 | const pair<string, ghobject_t>& r) | |
392 | { | |
393 | if (l.first < r.first) | |
394 | return true; | |
395 | if (l.first > r.first) | |
396 | return false; | |
397 | if (cmp(l.second, r.second) < 0) | |
398 | return true; | |
399 | return false; | |
400 | } | |
401 | }; | |
402 | ||
403 | struct CmpHexdigitStringBitwise { | |
404 | bool operator()(const string& l, const string& r) { | |
405 | return reverse_hexdigit_bits_string(l) < reverse_hexdigit_bits_string(r); | |
406 | } | |
407 | }; | |
408 | ||
409 | /// Get path contents by hash | |
410 | int get_path_contents_by_hash_bitwise( | |
411 | const vector<string> &path, /// [in] Path to list | |
412 | const ghobject_t *next_object, /// [in] list > *next_object | |
413 | set<string, CmpHexdigitStringBitwise> *hash_prefixes, /// [out] prefixes in dir | |
414 | set<pair<string, ghobject_t>, CmpPairBitwise> *objects /// [out] objects | |
415 | ); | |
416 | ||
417 | /// List objects in collection in ghobject_t order | |
418 | int list_by_hash( | |
419 | const vector<string> &path, /// [in] Path to list | |
420 | const ghobject_t &end, /// [in] List only objects < end | |
421 | int max_count, /// [in] List at most max_count | |
422 | ghobject_t *next, /// [in,out] List objects >= *next | |
423 | vector<ghobject_t> *out /// [out] Listed objects | |
424 | ); ///< @return Error Code, 0 on success | |
425 | /// List objects in collection in ghobject_t order | |
426 | int list_by_hash_bitwise( | |
427 | const vector<string> &path, /// [in] Path to list | |
428 | const ghobject_t &end, /// [in] List only objects < end | |
429 | int max_count, /// [in] List at most max_count | |
430 | ghobject_t *next, /// [in,out] List objects >= *next | |
431 | vector<ghobject_t> *out /// [out] Listed objects | |
432 | ); ///< @return Error Code, 0 on success | |
433 | ||
434 | /// Create the given levels of sub directories from the given root. | |
435 | /// The contents of *path* is not changed after calling this function. | |
436 | int recursive_create_path(vector<string>& path, int level); | |
437 | ||
438 | /// split each dir below the given path | |
439 | int split_dirs(const vector<string> &path); | |
224ce89b WB |
440 | |
441 | int write_settings(); | |
7c673cae FG |
442 | }; |
443 | ||
444 | #endif |