src/bin/lttng-relayd/index.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *               2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License, version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 51
  17  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #define _LGPL_SOURCE
  21 #include <assert.h>
  22
  23 #include <common/common.h>
  24 #include <common/utils.h>
  25 #include <common/compat/endian.h>
  26
  27 #include "lttng-relayd.h"
  28 #include "stream.h"
  29 #include "index.h"
  30 #include "connection.h"
  31
  32 /*
  33  * Allocate a new relay index object. Pass the stream in which it is
  34  * contained as parameter. The sequence number will be used as the hash
  35  * table key.
  36  *
  37  * Called with stream mutex held.
  38  * Return allocated object or else NULL on error.
  39  */
  40 static struct relay_index *relay_index_create(struct relay_stream *stream,
  41                 uint64_t net_seq_num)
  42 {
  43         struct relay_index *index;
  44
  45         DBG2("Creating relay index for stream id %" PRIu64 " and seqnum %" PRIu64,
  46                         stream->stream_handle, net_seq_num);
  47
  48         index = zmalloc(sizeof(*index));
  49         if (!index) {
  50                 PERROR("Relay index zmalloc");
  51                 goto end;
  52         }
  53         if (!stream_get(stream)) {
  54                 ERR("Cannot get stream");
  55                 free(index);
  56                 index = NULL;
  57                 goto end;
  58         }
  59         index->stream = stream;
  60
  61         lttng_ht_node_init_u64(&index->index_n, net_seq_num);
  62         pthread_mutex_init(&index->lock, NULL);
  63         urcu_ref_init(&index->ref);
  64
  65 end:
  66         return index;
  67 }
  68
  69 /*
  70  * Add unique relay index to the given hash table. In case of a collision, the
  71  * already existing object is put in the given _index variable.
  72  *
  73  * RCU read side lock MUST be acquired.
  74  */
  75 static struct relay_index *relay_index_add_unique(struct relay_stream *stream,
  76                 struct relay_index *index)
  77 {
  78         struct cds_lfht_node *node_ptr;
  79         struct relay_index *_index;
  80
  81         DBG2("Adding relay index with stream id %" PRIu64 " and seqnum %" PRIu64,
  82                         stream->stream_handle, index->index_n.key);
  83
  84         node_ptr = cds_lfht_add_unique(stream->indexes_ht->ht,
  85                         stream->indexes_ht->hash_fct(&index->index_n, lttng_ht_seed),
  86                         stream->indexes_ht->match_fct, &index->index_n,
  87                         &index->index_n.node);
  88         if (node_ptr != &index->index_n.node) {
  89                 _index = caa_container_of(node_ptr, struct relay_index,
  90                                 index_n.node);
  91         } else {
  92                 _index = NULL;
  93         }
  94         return _index;
  95 }
  96
  97 /*
  98  * Should be called with RCU read-side lock held.
  99  */
 100 static bool relay_index_get(struct relay_index *index)
 101 {
 102         DBG2("index get for stream id %" PRIu64 " and seqnum %" PRIu64 " refcount %d",
 103                         index->stream->stream_handle, index->index_n.key,
 104                         (int) index->ref.refcount);
 105
 106         return urcu_ref_get_unless_zero(&index->ref);
 107 }
 108
 109 /*
 110  * Get a relayd index in within the given stream, or create it if not
 111  * present.
 112  *
 113  * Called with stream mutex held.
 114  * Return index object or else NULL on error.
 115  */
 116 struct relay_index *relay_index_get_by_id_or_create(struct relay_stream *stream,
 117                  uint64_t net_seq_num)
 118 {
 119         struct lttng_ht_node_u64 *node;
 120         struct lttng_ht_iter iter;
 121         struct relay_index *index = NULL;
 122
 123         DBG3("Finding index for stream id %" PRIu64 " and seq_num %" PRIu64,
 124                         stream->stream_handle, net_seq_num);
 125
 126         rcu_read_lock();
 127         lttng_ht_lookup(stream->indexes_ht, &net_seq_num, &iter);
 128         node = lttng_ht_iter_get_node_u64(&iter);
 129         if (node) {
 130                 index = caa_container_of(node, struct relay_index, index_n);
 131         } else {
 132                 struct relay_index *oldindex;
 133
 134                 index = relay_index_create(stream, net_seq_num);
 135                 if (!index) {
 136                         ERR("Cannot create index for stream id %" PRIu64 " and seq_num %" PRIu64,
 137                                 stream->stream_handle, net_seq_num);
 138                         goto end;
 139                 }
 140                 oldindex = relay_index_add_unique(stream, index);
 141                 if (oldindex) {
 142                         /* Added concurrently, keep old. */
 143                         relay_index_put(index);
 144                         index = oldindex;
 145                         if (!relay_index_get(index)) {
 146                                 index = NULL;
 147                         }
 148                 } else {
 149                         stream->indexes_in_flight++;
 150                         index->in_hash_table = true;
 151                 }
 152         }
 153 end:
 154         rcu_read_unlock();
 155         DBG2("Index %sfound or created in HT for stream ID %" PRIu64 " and seqnum %" PRIu64,
 156                         (index == NULL) ? "NOT " : "", stream->stream_handle, net_seq_num);
 157         return index;
 158 }
 159
 160 int relay_index_set_file(struct relay_index *index,
 161                 struct lttng_index_file *index_file,
 162                 uint64_t data_offset)
 163 {
 164         int ret = 0;
 165
 166         pthread_mutex_lock(&index->lock);
 167         if (index->index_file) {
 168                 ret = -1;
 169                 goto end;
 170         }
 171         lttng_index_file_get(index_file);
 172         index->index_file = index_file;
 173         index->index_data.offset = data_offset;
 174 end:
 175         pthread_mutex_unlock(&index->lock);
 176         return ret;
 177 }
 178
 179 int relay_index_set_data(struct relay_index *index,
 180                 const struct ctf_packet_index *data)
 181 {
 182         int ret = 0;
 183
 184         pthread_mutex_lock(&index->lock);
 185         if (index->has_index_data) {
 186                 ret = -1;
 187                 goto end;
 188         }
 189         /* Set everything except data_offset. */
 190         index->index_data.packet_size = data->packet_size;
 191         index->index_data.content_size = data->content_size;
 192         index->index_data.timestamp_begin = data->timestamp_begin;
 193         index->index_data.timestamp_end = data->timestamp_end;
 194         index->index_data.events_discarded = data->events_discarded;
 195         index->index_data.stream_id = data->stream_id;
 196         index->has_index_data = true;
 197 end:
 198         pthread_mutex_unlock(&index->lock);
 199         return ret;
 200 }
 201
 202 static void index_destroy(struct relay_index *index)
 203 {
 204         free(index);
 205 }
 206
 207 static void index_destroy_rcu(struct rcu_head *rcu_head)
 208 {
 209         struct relay_index *index =
 210                 caa_container_of(rcu_head, struct relay_index, rcu_node);
 211
 212         index_destroy(index);
 213 }
 214
 215 /* Stream lock must be held by the caller. */
 216 static void index_release(struct urcu_ref *ref)
 217 {
 218         struct relay_index *index = caa_container_of(ref, struct relay_index, ref);
 219         struct relay_stream *stream = index->stream;
 220         int ret;
 221         struct lttng_ht_iter iter;
 222
 223         if (index->index_file) {
 224                 lttng_index_file_put(index->index_file);
 225                 index->index_file = NULL;
 226         }
 227         if (index->in_hash_table) {
 228                 /* Delete index from hash table. */
 229                 iter.iter.node = &index->index_n.node;
 230                 ret = lttng_ht_del(stream->indexes_ht, &iter);
 231                 assert(!ret);
 232                 stream->indexes_in_flight--;
 233         }
 234
 235         stream_put(index->stream);
 236         index->stream = NULL;
 237
 238         call_rcu(&index->rcu_node, index_destroy_rcu);
 239 }
 240
 241 /*
 242  * Called with stream mutex held.
 243  *
 244  * Stream lock must be held by the caller.
 245  */
 246 void relay_index_put(struct relay_index *index)
 247 {
 248         DBG2("index put for stream id %" PRIu64 " and seqnum %" PRIu64 " refcount %d",
 249                         index->stream->stream_handle, index->index_n.key,
 250                         (int) index->ref.refcount);
 251         /*
 252          * Ensure existance of index->lock for index unlock.
 253          */
 254         rcu_read_lock();
 255         /*
 256          * Index lock ensures that concurrent test and update of stream
 257          * ref is atomic.
 258          */
 259         assert(index->ref.refcount != 0);
 260         urcu_ref_put(&index->ref, index_release);
 261         rcu_read_unlock();
 262 }
 263
 264 /*
 265  * Try to flush index to disk. Releases self-reference to index once
 266  * flush succeeds.
 267  *
 268  * Stream lock must be held by the caller.
 269  * Return 0 on successful flush, a negative value on error, or positive
 270  * value if no flush was performed.
 271  */
 272 int relay_index_try_flush(struct relay_index *index)
 273 {
 274         int ret = 1;
 275         bool flushed = false;
 276
 277         pthread_mutex_lock(&index->lock);
 278         if (index->flushed) {
 279                 goto skip;
 280         }
 281         /* Check if we are ready to flush. */
 282         if (!index->has_index_data || !index->index_file) {
 283                 goto skip;
 284         }
 285
 286         DBG2("Writing index for stream ID %" PRIu64 " and seq num %" PRIu64,
 287                         index->stream->stream_handle, index->index_n.key);
 288         flushed = true;
 289         index->flushed = true;
 290         ret = lttng_index_file_write(index->index_file, &index->index_data);
 291 skip:
 292         pthread_mutex_unlock(&index->lock);
 293
 294         if (flushed) {
 295                 /* Put self-ref from index now that it has been flushed. */
 296                 relay_index_put(index);
 297         }
 298         return ret;
 299 }
 300
 301 /*
 302  * Close every relay index within a given stream, without flushing
 303  * them.
 304  */
 305 void relay_index_close_all(struct relay_stream *stream)
 306 {
 307         struct lttng_ht_iter iter;
 308         struct relay_index *index;
 309
 310         rcu_read_lock();
 311         cds_lfht_for_each_entry(stream->indexes_ht->ht, &iter.iter,
 312                         index, index_n.node) {
 313                 /* Put self-ref from index. */
 314                 relay_index_put(index);
 315         }
 316         rcu_read_unlock();
 317 }
 318
 319 void relay_index_close_partial_fd(struct relay_stream *stream)
 320 {
 321         struct lttng_ht_iter iter;
 322         struct relay_index *index;
 323
 324         rcu_read_lock();
 325         cds_lfht_for_each_entry(stream->indexes_ht->ht, &iter.iter,
 326                         index, index_n.node) {
 327                 if (!index->index_file) {
 328                         continue;
 329                 }
 330                 /*
 331                  * Partial index has its index_file: we have only
 332                  * received its info from the data socket.
 333                  * Put self-ref from index.
 334                  */
 335                 relay_index_put(index);
 336         }
 337         rcu_read_unlock();
 338 }
 339
 340 uint64_t relay_index_find_last(struct relay_stream *stream)
 341 {
 342         struct lttng_ht_iter iter;
 343         struct relay_index *index;
 344         uint64_t net_seq_num = -1ULL;
 345
 346         rcu_read_lock();
 347         cds_lfht_for_each_entry(stream->indexes_ht->ht, &iter.iter,
 348                         index, index_n.node) {
 349                 if (net_seq_num == -1ULL ||
 350                                 index->index_n.key > net_seq_num) {
 351                         net_seq_num = index->index_n.key;
 352                 }
 353         }
 354         rcu_read_unlock();
 355         return net_seq_num;
 356 }
 357
 358 /*
 359  * Update the index file of an already existing relay_index.
 360  * Offsets by 'removed_data_count' the offset field of an index.
 361  */
 362 static
 363 int relay_index_switch_file(struct relay_index *index,
 364                 struct lttng_index_file *new_index_file,
 365                 uint64_t removed_data_count)
 366 {
 367         int ret = 0;
 368         uint64_t offset;
 369
 370         pthread_mutex_lock(&index->lock);
 371         if (!index->index_file) {
 372                 ERR("No index_file");
 373                 ret = 0;
 374                 goto end;
 375         }
 376
 377         lttng_index_file_put(index->index_file);
 378         lttng_index_file_get(new_index_file);
 379         index->index_file = new_index_file;
 380         offset = be64toh(index->index_data.offset);
 381         index->index_data.offset = htobe64(offset - removed_data_count);
 382
 383 end:
 384         pthread_mutex_unlock(&index->lock);
 385         return ret;
 386 }
 387
 388 /*
 389  * Switch the index file of all pending indexes for a stream and update the
 390  * data offset by substracting the last safe position.
 391  * Stream lock must be held.
 392  */
 393 int relay_index_switch_all_files(struct relay_stream *stream)
 394 {
 395         struct lttng_ht_iter iter;
 396         struct relay_index *index;
 397         int ret = 0;
 398
 399         rcu_read_lock();
 400         cds_lfht_for_each_entry(stream->indexes_ht->ht, &iter.iter,
 401                         index, index_n.node) {
 402                 ret = relay_index_switch_file(index, stream->index_file,
 403                                 stream->pos_after_last_complete_data_index);
 404                 if (ret) {
 405                         goto end;
 406                 }
 407         }
 408 end:
 409         rcu_read_unlock();
 410         return ret;
 411 }
 412
 413 /*
 414  * Set index data from the control port to a given index object.
 415  */
 416 int relay_index_set_control_data(struct relay_index *index,
 417                 const struct lttcomm_relayd_index *data,
 418                 unsigned int minor_version)
 419 {
 420         /* The index on disk is encoded in big endian. */
 421         const struct ctf_packet_index index_data = {
 422                 .packet_size = htobe64(data->packet_size),
 423                 .content_size = htobe64(data->content_size),
 424                 .timestamp_begin = htobe64(data->timestamp_begin),
 425                 .timestamp_end = htobe64(data->timestamp_end),
 426                 .events_discarded = htobe64(data->events_discarded),
 427                 .stream_id = htobe64(data->stream_id),
 428         };
 429
 430         if (minor_version >= 8) {
 431                 index->index_data.stream_instance_id = htobe64(data->stream_instance_id);
 432                 index->index_data.packet_seq_num = htobe64(data->packet_seq_num);
 433         } else {
 434                 uint64_t unset_value = -1ULL;
 435
 436                 index->index_data.stream_instance_id = htobe64(unset_value);
 437                 index->index_data.packet_seq_num = htobe64(unset_value);
 438         }
 439
 440         return relay_index_set_data(index, &index_data);
 441 }