src/bin/lttng-relayd/index.cpp

   1 /*
   2  * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
   3  * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
   4  * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * SPDX-License-Identifier: GPL-2.0-only
   7  *
   8  */
   9
  10 #define _LGPL_SOURCE
  11
  12 #include "connection.hpp"
  13 #include "index.hpp"
  14 #include "lttng-relayd.hpp"
  15 #include "stream.hpp"
  16
  17 #include <common/common.hpp>
  18 #include <common/compat/endian.hpp>
  19 #include <common/utils.hpp>
  20
  21 /*
  22  * Allocate a new relay index object. Pass the stream in which it is
  23  * contained as parameter. The sequence number will be used as the hash
  24  * table key.
  25  *
  26  * Called with stream mutex held.
  27  * Return allocated object or else NULL on error.
  28  */
  29 static struct relay_index *relay_index_create(struct relay_stream *stream, uint64_t net_seq_num)
  30 {
  31         struct relay_index *index;
  32
  33         DBG2("Creating relay index for stream id %" PRIu64 " and seqnum %" PRIu64,
  34              stream->stream_handle,
  35              net_seq_num);
  36
  37         index = zmalloc<relay_index>();
  38         if (!index) {
  39                 PERROR("Relay index zmalloc");
  40                 goto end;
  41         }
  42         if (!stream_get(stream)) {
  43                 ERR("Cannot get stream");
  44                 free(index);
  45                 index = nullptr;
  46                 goto end;
  47         }
  48         index->stream = stream;
  49
  50         lttng_ht_node_init_u64(&index->index_n, net_seq_num);
  51         pthread_mutex_init(&index->lock, nullptr);
  52         urcu_ref_init(&index->ref);
  53
  54 end:
  55         return index;
  56 }
  57
  58 /*
  59  * Add unique relay index to the given hash table. In case of a collision, the
  60  * already existing object is put in the given _index variable.
  61  *
  62  * RCU read side lock MUST be acquired.
  63  */
  64 static struct relay_index *relay_index_add_unique(struct relay_stream *stream,
  65                                                   struct relay_index *index)
  66 {
  67         struct cds_lfht_node *node_ptr;
  68         struct relay_index *_index;
  69
  70         ASSERT_RCU_READ_LOCKED();
  71
  72         DBG2("Adding relay index with stream id %" PRIu64 " and seqnum %" PRIu64,
  73              stream->stream_handle,
  74              index->index_n.key);
  75
  76         node_ptr = cds_lfht_add_unique(stream->indexes_ht->ht,
  77                                        stream->indexes_ht->hash_fct(&index->index_n, lttng_ht_seed),
  78                                        stream->indexes_ht->match_fct,
  79                                        &index->index_n,
  80                                        &index->index_n.node);
  81         if (node_ptr != &index->index_n.node) {
  82                 _index = caa_container_of(node_ptr, struct relay_index, index_n.node);
  83         } else {
  84                 _index = nullptr;
  85         }
  86         return _index;
  87 }
  88
  89 /*
  90  * Should be called with RCU read-side lock held.
  91  */
  92 static bool relay_index_get(struct relay_index *index)
  93 {
  94         ASSERT_RCU_READ_LOCKED();
  95
  96         DBG2("index get for stream id %" PRIu64 " and seqnum %" PRIu64 " refcount %d",
  97              index->stream->stream_handle,
  98              index->index_n.key,
  99              (int) index->ref.refcount);
 100
 101         return urcu_ref_get_unless_zero(&index->ref);
 102 }
 103
 104 /*
 105  * Get a relayd index in within the given stream, or create it if not
 106  * present.
 107  *
 108  * Called with stream mutex held.
 109  * Return index object or else NULL on error.
 110  */
 111 struct relay_index *relay_index_get_by_id_or_create(struct relay_stream *stream,
 112                                                     uint64_t net_seq_num)
 113 {
 114         struct lttng_ht_node_u64 *node;
 115         struct lttng_ht_iter iter;
 116         struct relay_index *index = nullptr;
 117
 118         DBG3("Finding index for stream id %" PRIu64 " and seq_num %" PRIu64,
 119              stream->stream_handle,
 120              net_seq_num);
 121
 122         rcu_read_lock();
 123         lttng_ht_lookup(stream->indexes_ht, &net_seq_num, &iter);
 124         node = lttng_ht_iter_get_node_u64(&iter);
 125         if (node) {
 126                 index = lttng::utils::container_of(node, &relay_index::index_n);
 127         } else {
 128                 struct relay_index *oldindex;
 129
 130                 index = relay_index_create(stream, net_seq_num);
 131                 if (!index) {
 132                         ERR("Cannot create index for stream id %" PRIu64 " and seq_num %" PRIu64,
 133                             stream->stream_handle,
 134                             net_seq_num);
 135                         goto end;
 136                 }
 137                 oldindex = relay_index_add_unique(stream, index);
 138                 if (oldindex) {
 139                         /* Added concurrently, keep old. */
 140                         relay_index_put(index);
 141                         index = oldindex;
 142                         if (!relay_index_get(index)) {
 143                                 index = nullptr;
 144                         }
 145                 } else {
 146                         stream->indexes_in_flight++;
 147                         index->in_hash_table = true;
 148                 }
 149         }
 150 end:
 151         rcu_read_unlock();
 152         DBG2("Index %sfound or created in HT for stream ID %" PRIu64 " and seqnum %" PRIu64,
 153              (index == NULL) ? "NOT " : "",
 154              stream->stream_handle,
 155              net_seq_num);
 156         return index;
 157 }
 158
 159 int relay_index_set_file(struct relay_index *index,
 160                          struct lttng_index_file *index_file,
 161                          uint64_t data_offset)
 162 {
 163         int ret = 0;
 164
 165         pthread_mutex_lock(&index->lock);
 166         if (index->index_file) {
 167                 ret = -1;
 168                 goto end;
 169         }
 170         lttng_index_file_get(index_file);
 171         index->index_file = index_file;
 172         index->index_data.offset = data_offset;
 173 end:
 174         pthread_mutex_unlock(&index->lock);
 175         return ret;
 176 }
 177
 178 int relay_index_set_data(struct relay_index *index, const struct ctf_packet_index *data)
 179 {
 180         int ret = 0;
 181
 182         pthread_mutex_lock(&index->lock);
 183         if (index->has_index_data) {
 184                 ret = -1;
 185                 goto end;
 186         }
 187         /* Set everything except data_offset. */
 188         index->index_data.packet_size = data->packet_size;
 189         index->index_data.content_size = data->content_size;
 190         index->index_data.timestamp_begin = data->timestamp_begin;
 191         index->index_data.timestamp_end = data->timestamp_end;
 192         index->index_data.events_discarded = data->events_discarded;
 193         index->index_data.stream_id = data->stream_id;
 194         index->has_index_data = true;
 195 end:
 196         pthread_mutex_unlock(&index->lock);
 197         return ret;
 198 }
 199
 200 static void index_destroy(struct relay_index *index)
 201 {
 202         free(index);
 203 }
 204
 205 static void index_destroy_rcu(struct rcu_head *rcu_head)
 206 {
 207         struct relay_index *index = lttng::utils::container_of(rcu_head, &relay_index::rcu_node);
 208
 209         index_destroy(index);
 210 }
 211
 212 /* Stream lock must be held by the caller. */
 213 static void index_release(struct urcu_ref *ref)
 214 {
 215         struct relay_index *index = lttng::utils::container_of(ref, &relay_index::ref);
 216         struct relay_stream *stream = index->stream;
 217         int ret;
 218         struct lttng_ht_iter iter;
 219
 220         if (index->index_file) {
 221                 lttng_index_file_put(index->index_file);
 222                 index->index_file = nullptr;
 223         }
 224         if (index->in_hash_table) {
 225                 /* Delete index from hash table. */
 226                 iter.iter.node = &index->index_n.node;
 227                 ret = lttng_ht_del(stream->indexes_ht, &iter);
 228                 LTTNG_ASSERT(!ret);
 229                 stream->indexes_in_flight--;
 230         }
 231
 232         stream_put(index->stream);
 233         index->stream = nullptr;
 234
 235         call_rcu(&index->rcu_node, index_destroy_rcu);
 236 }
 237
 238 /*
 239  * Called with stream mutex held.
 240  *
 241  * Stream lock must be held by the caller.
 242  */
 243 void relay_index_put(struct relay_index *index)
 244 {
 245         DBG2("index put for stream id %" PRIu64 " and seqnum %" PRIu64 " refcount %d",
 246              index->stream->stream_handle,
 247              index->index_n.key,
 248              (int) index->ref.refcount);
 249         /*
 250          * Ensure existence of index->lock for index unlock.
 251          */
 252         rcu_read_lock();
 253         /*
 254          * Index lock ensures that concurrent test and update of stream
 255          * ref is atomic.
 256          */
 257         LTTNG_ASSERT(index->ref.refcount != 0);
 258         urcu_ref_put(&index->ref, index_release);
 259         rcu_read_unlock();
 260 }
 261
 262 /*
 263  * Try to flush index to disk. Releases self-reference to index once
 264  * flush succeeds.
 265  *
 266  * Stream lock must be held by the caller.
 267  * Return 0 on successful flush, a negative value on error, or positive
 268  * value if no flush was performed.
 269  */
 270 int relay_index_try_flush(struct relay_index *index)
 271 {
 272         int ret = 1;
 273         bool flushed = false;
 274
 275         pthread_mutex_lock(&index->lock);
 276         if (index->flushed) {
 277                 goto skip;
 278         }
 279         /* Check if we are ready to flush. */
 280         if (!index->has_index_data || !index->index_file) {
 281                 goto skip;
 282         }
 283
 284         DBG2("Writing index for stream ID %" PRIu64 " and seq num %" PRIu64,
 285              index->stream->stream_handle,
 286              index->index_n.key);
 287         flushed = true;
 288         index->flushed = true;
 289         ret = lttng_index_file_write(index->index_file, &index->index_data);
 290 skip:
 291         pthread_mutex_unlock(&index->lock);
 292
 293         if (flushed) {
 294                 /* Put self-ref from index now that it has been flushed. */
 295                 relay_index_put(index);
 296         }
 297         return ret;
 298 }
 299
 300 /*
 301  * Close every relay index within a given stream, without flushing
 302  * them.
 303  */
 304 void relay_index_close_all(struct relay_stream *stream)
 305 {
 306         struct lttng_ht_iter iter;
 307         struct relay_index *index;
 308
 309         rcu_read_lock();
 310         cds_lfht_for_each_entry (stream->indexes_ht->ht, &iter.iter, index, index_n.node) {
 311                 /* Put self-ref from index. */
 312                 relay_index_put(index);
 313         }
 314         rcu_read_unlock();
 315 }
 316
 317 void relay_index_close_partial_fd(struct relay_stream *stream)
 318 {
 319         struct lttng_ht_iter iter;
 320         struct relay_index *index;
 321
 322         rcu_read_lock();
 323         cds_lfht_for_each_entry (stream->indexes_ht->ht, &iter.iter, index, index_n.node) {
 324                 if (!index->index_file) {
 325                         continue;
 326                 }
 327                 /*
 328                  * Partial index has its index_file: we have only
 329                  * received its info from the data socket.
 330                  * Put self-ref from index.
 331                  */
 332                 relay_index_put(index);
 333         }
 334         rcu_read_unlock();
 335 }
 336
 337 uint64_t relay_index_find_last(struct relay_stream *stream)
 338 {
 339         struct lttng_ht_iter iter;
 340         struct relay_index *index;
 341         uint64_t net_seq_num = -1ULL;
 342
 343         rcu_read_lock();
 344         cds_lfht_for_each_entry (stream->indexes_ht->ht, &iter.iter, index, index_n.node) {
 345                 if (net_seq_num == -1ULL || index->index_n.key > net_seq_num) {
 346                         net_seq_num = index->index_n.key;
 347                 }
 348         }
 349         rcu_read_unlock();
 350         return net_seq_num;
 351 }
 352
 353 /*
 354  * Update the index file of an already existing relay_index.
 355  * Offsets by 'removed_data_count' the offset field of an index.
 356  */
 357 static int relay_index_switch_file(struct relay_index *index,
 358                                    struct lttng_index_file *new_index_file,
 359                                    uint64_t removed_data_count)
 360 {
 361         int ret = 0;
 362         uint64_t offset;
 363
 364         pthread_mutex_lock(&index->lock);
 365         if (!index->index_file) {
 366                 ERR("No index_file");
 367                 ret = 0;
 368                 goto end;
 369         }
 370
 371         lttng_index_file_put(index->index_file);
 372         lttng_index_file_get(new_index_file);
 373         index->index_file = new_index_file;
 374         offset = be64toh(index->index_data.offset);
 375         index->index_data.offset = htobe64(offset - removed_data_count);
 376
 377 end:
 378         pthread_mutex_unlock(&index->lock);
 379         return ret;
 380 }
 381
 382 /*
 383  * Switch the index file of all pending indexes for a stream and update the
 384  * data offset by substracting the last safe position.
 385  * Stream lock must be held.
 386  */
 387 int relay_index_switch_all_files(struct relay_stream *stream)
 388 {
 389         struct lttng_ht_iter iter;
 390         struct relay_index *index;
 391         int ret = 0;
 392
 393         rcu_read_lock();
 394         cds_lfht_for_each_entry (stream->indexes_ht->ht, &iter.iter, index, index_n.node) {
 395                 ret = relay_index_switch_file(
 396                         index, stream->index_file, stream->pos_after_last_complete_data_index);
 397                 if (ret) {
 398                         goto end;
 399                 }
 400         }
 401 end:
 402         rcu_read_unlock();
 403         return ret;
 404 }
 405
 406 /*
 407  * Set index data from the control port to a given index object.
 408  */
 409 int relay_index_set_control_data(struct relay_index *index,
 410                                  const struct lttcomm_relayd_index *data,
 411                                  unsigned int minor_version)
 412 {
 413         /* The index on disk is encoded in big endian. */
 414         ctf_packet_index index_data{};
 415
 416         index_data.packet_size = htobe64(data->packet_size);
 417         index_data.content_size = htobe64(data->content_size);
 418         index_data.timestamp_begin = htobe64(data->timestamp_begin);
 419         index_data.timestamp_end = htobe64(data->timestamp_end);
 420         index_data.events_discarded = htobe64(data->events_discarded);
 421         index_data.stream_id = htobe64(data->stream_id);
 422
 423         if (minor_version >= 8) {
 424                 index->index_data.stream_instance_id = htobe64(data->stream_instance_id);
 425                 index->index_data.packet_seq_num = htobe64(data->packet_seq_num);
 426         } else {
 427                 uint64_t unset_value = -1ULL;
 428
 429                 index->index_data.stream_instance_id = htobe64(unset_value);
 430                 index->index_data.packet_seq_num = htobe64(unset_value);
 431         }
 432
 433         return relay_index_set_data(index, &index_data);
 434 }