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/urcu.hpp>
  20 #include <common/utils.hpp>
  21
  22 /*
  23  * Allocate a new relay index object. Pass the stream in which it is
  24  * contained as parameter. The sequence number will be used as the hash
  25  * table key.
  26  *
  27  * Called with stream mutex held.
  28  * Return allocated object or else NULL on error.
  29  */
  30 static struct relay_index *relay_index_create(struct relay_stream *stream, uint64_t net_seq_num)
  31 {
  32         struct relay_index *index;
  33
  34         DBG2("Creating relay index for stream id %" PRIu64 " and seqnum %" PRIu64,
  35              stream->stream_handle,
  36              net_seq_num);
  37
  38         index = zmalloc<relay_index>();
  39         if (!index) {
  40                 PERROR("Relay index zmalloc");
  41                 goto end;
  42         }
  43         if (!stream_get(stream)) {
  44                 ERR("Cannot get stream");
  45                 free(index);
  46                 index = nullptr;
  47                 goto end;
  48         }
  49         index->stream = stream;
  50
  51         lttng_ht_node_init_u64(&index->index_n, net_seq_num);
  52         pthread_mutex_init(&index->lock, nullptr);
  53         urcu_ref_init(&index->ref);
  54
  55 end:
  56         return index;
  57 }
  58
  59 /*
  60  * Add unique relay index to the given hash table. In case of a collision, the
  61  * already existing object is put in the given _index variable.
  62  *
  63  * RCU read side lock MUST be acquired.
  64  */
  65 static struct relay_index *relay_index_add_unique(struct relay_stream *stream,
  66                                                   struct relay_index *index)
  67 {
  68         struct cds_lfht_node *node_ptr;
  69         struct relay_index *_index;
  70
  71         ASSERT_RCU_READ_LOCKED();
  72
  73         DBG2("Adding relay index with stream id %" PRIu64 " and seqnum %" PRIu64,
  74              stream->stream_handle,
  75              index->index_n.key);
  76
  77         node_ptr = cds_lfht_add_unique(stream->indexes_ht->ht,
  78                                        stream->indexes_ht->hash_fct(&index->index_n.key, lttng_ht_seed),
  79                                        stream->indexes_ht->match_fct,
  80                                        &index->index_n.key,
  81                                        &index->index_n.node);
  82         if (node_ptr != &index->index_n.node) {
  83                 _index = lttng_ht_node_container_of(node_ptr, &relay_index::index_n);
  84         } else {
  85                 _index = nullptr;
  86         }
  87         return _index;
  88 }
  89
  90 /*
  91  * Should be called with RCU read-side lock held.
  92  */
  93 static bool relay_index_get(struct relay_index *index)
  94 {
  95         ASSERT_RCU_READ_LOCKED();
  96
  97         DBG2("index get for stream id %" PRIu64 " and seqnum %" PRIu64 " refcount %d",
  98              index->stream->stream_handle,
  99              index->index_n.key,
 100              (int) index->ref.refcount);
 101
 102         return urcu_ref_get_unless_zero(&index->ref);
 103 }
 104
 105 /*
 106  * Get a relayd index in within the given stream, or create it if not
 107  * present.
 108  *
 109  * Called with stream mutex held.
 110  * Return index object or else NULL on error.
 111  */
 112 struct relay_index *relay_index_get_by_id_or_create(struct relay_stream *stream,
 113                                                     uint64_t net_seq_num)
 114 {
 115         struct lttng_ht_node_u64 *node;
 116         struct lttng_ht_iter iter;
 117         struct relay_index *index = nullptr;
 118
 119         DBG3("Finding index for stream id %" PRIu64 " and seq_num %" PRIu64,
 120              stream->stream_handle,
 121              net_seq_num);
 122
 123         const lttng::urcu::read_lock_guard read_lock;
 124         lttng_ht_lookup(stream->indexes_ht, &net_seq_num, &iter);
 125         node = lttng_ht_iter_get_node<lttng_ht_node_u64>(&iter);
 126         if (node) {
 127                 index = lttng::utils::container_of(node, &relay_index::index_n);
 128         } else {
 129                 struct relay_index *oldindex;
 130
 131                 index = relay_index_create(stream, net_seq_num);
 132                 if (!index) {
 133                         ERR("Cannot create index for stream id %" PRIu64 " and seq_num %" PRIu64,
 134                             stream->stream_handle,
 135                             net_seq_num);
 136                         goto end;
 137                 }
 138                 oldindex = relay_index_add_unique(stream, index);
 139                 if (oldindex) {
 140                         /* Added concurrently, keep old. */
 141                         relay_index_put(index);
 142                         index = oldindex;
 143                         if (!relay_index_get(index)) {
 144                                 index = nullptr;
 145                         }
 146                 } else {
 147                         stream->indexes_in_flight++;
 148                         index->in_hash_table = true;
 149                 }
 150         }
 151 end:
 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         const lttng::urcu::read_lock_guard 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 }
 260
 261 /*
 262  * Try to flush index to disk. Releases self-reference to index once
 263  * flush succeeds.
 264  *
 265  * Stream lock must be held by the caller.
 266  * Return 0 on successful flush, a negative value on error, or positive
 267  * value if no flush was performed.
 268  */
 269 int relay_index_try_flush(struct relay_index *index)
 270 {
 271         int ret = 1;
 272         bool flushed = false;
 273
 274         pthread_mutex_lock(&index->lock);
 275         if (index->flushed) {
 276                 goto skip;
 277         }
 278         /* Check if we are ready to flush. */
 279         if (!index->has_index_data || !index->index_file) {
 280                 goto skip;
 281         }
 282
 283         DBG2("Writing index for stream ID %" PRIu64 " and seq num %" PRIu64,
 284              index->stream->stream_handle,
 285              index->index_n.key);
 286         flushed = true;
 287         index->flushed = true;
 288         ret = lttng_index_file_write(index->index_file, &index->index_data);
 289 skip:
 290         pthread_mutex_unlock(&index->lock);
 291
 292         if (flushed) {
 293                 /* Put self-ref from index now that it has been flushed. */
 294                 relay_index_put(index);
 295         }
 296         return ret;
 297 }
 298
 299 /*
 300  * Close every relay index within a given stream, without flushing
 301  * them.
 302  */
 303 void relay_index_close_all(struct relay_stream *stream)
 304 {
 305         for (auto *index :
 306              lttng::urcu::lfht_iteration_adapter<relay_index,
 307                                                  decltype(relay_index::index_n),
 308                                                  &relay_index::index_n>(*stream->indexes_ht->ht)) {
 309                 /* Put self-ref from index. */
 310                 relay_index_put(index);
 311         }
 312 }
 313
 314 void relay_index_close_partial_fd(struct relay_stream *stream)
 315 {
 316         for (auto *index :
 317              lttng::urcu::lfht_iteration_adapter<relay_index,
 318                                                  decltype(relay_index::index_n),
 319                                                  &relay_index::index_n>(*stream->indexes_ht->ht)) {
 320                 if (!index->index_file) {
 321                         continue;
 322                 }
 323                 /*
 324                  * Partial index has its index_file: we have only
 325                  * received its info from the data socket.
 326                  * Put self-ref from index.
 327                  */
 328                 relay_index_put(index);
 329         }
 330 }
 331
 332 uint64_t relay_index_find_last(struct relay_stream *stream)
 333 {
 334         uint64_t net_seq_num = -1ULL;
 335
 336         for (auto *index :
 337              lttng::urcu::lfht_iteration_adapter<relay_index,
 338                                                  decltype(relay_index::index_n),
 339                                                  &relay_index::index_n>(*stream->indexes_ht->ht)) {
 340                 if (net_seq_num == -1ULL || index->index_n.key > net_seq_num) {
 341                         net_seq_num = index->index_n.key;
 342                 }
 343         }
 344
 345         return net_seq_num;
 346 }
 347
 348 /*
 349  * Update the index file of an already existing relay_index.
 350  * Offsets by 'removed_data_count' the offset field of an index.
 351  */
 352 static int relay_index_switch_file(struct relay_index *index,
 353                                    struct lttng_index_file *new_index_file,
 354                                    uint64_t removed_data_count)
 355 {
 356         int ret = 0;
 357         uint64_t offset;
 358
 359         pthread_mutex_lock(&index->lock);
 360         if (!index->index_file) {
 361                 ERR("No index_file");
 362                 ret = 0;
 363                 goto end;
 364         }
 365
 366         lttng_index_file_put(index->index_file);
 367         lttng_index_file_get(new_index_file);
 368         index->index_file = new_index_file;
 369         offset = be64toh(index->index_data.offset);
 370         index->index_data.offset = htobe64(offset - removed_data_count);
 371
 372 end:
 373         pthread_mutex_unlock(&index->lock);
 374         return ret;
 375 }
 376
 377 /*
 378  * Switch the index file of all pending indexes for a stream and update the
 379  * data offset by substracting the last safe position.
 380  * Stream lock must be held.
 381  */
 382 int relay_index_switch_all_files(struct relay_stream *stream)
 383 {
 384         for (auto *index :
 385              lttng::urcu::lfht_iteration_adapter<relay_index,
 386                                                  decltype(relay_index::index_n),
 387                                                  &relay_index::index_n>(*stream->indexes_ht->ht)) {
 388                 const auto ret = relay_index_switch_file(
 389                         index, stream->index_file, stream->pos_after_last_complete_data_index);
 390                 if (ret) {
 391                         return ret;
 392                 }
 393         }
 394
 395         return 0;
 396 }
 397
 398 /*
 399  * Set index data from the control port to a given index object.
 400  */
 401 int relay_index_set_control_data(struct relay_index *index,
 402                                  const struct lttcomm_relayd_index *data,
 403                                  unsigned int minor_version)
 404 {
 405         /* The index on disk is encoded in big endian. */
 406         ctf_packet_index index_data{};
 407
 408         index_data.packet_size = htobe64(data->packet_size);
 409         index_data.content_size = htobe64(data->content_size);
 410         index_data.timestamp_begin = htobe64(data->timestamp_begin);
 411         index_data.timestamp_end = htobe64(data->timestamp_end);
 412         index_data.events_discarded = htobe64(data->events_discarded);
 413         index_data.stream_id = htobe64(data->stream_id);
 414
 415         if (minor_version >= 8) {
 416                 index->index_data.stream_instance_id = htobe64(data->stream_instance_id);
 417                 index->index_data.packet_seq_num = htobe64(data->packet_seq_num);
 418         } else {
 419                 const uint64_t unset_value = -1ULL;
 420
 421                 index->index_data.stream_instance_id = htobe64(unset_value);
 422                 index->index_data.packet_seq_num = htobe64(unset_value);
 423         }
 424
 425         return relay_index_set_data(index, &index_data);
 426 }