ovsdb/file.c

   1 /* Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
   2  *
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #include <config.h>
  17
  18 #include "file.h"
  19
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <unistd.h>
  23
  24 #include "bitmap.h"
  25 #include "column.h"
  26 #include "log.h"
  27 #include "json.h"
  28 #include "lockfile.h"
  29 #include "ovsdb.h"
  30 #include "ovsdb-error.h"
  31 #include "row.h"
  32 #include "socket-util.h"
  33 #include "table.h"
  34 #include "timeval.h"
  35 #include "transaction.h"
  36 #include "uuid.h"
  37 #include "util.h"
  38 #include "openvswitch/vlog.h"
  39
  40 VLOG_DEFINE_THIS_MODULE(ovsdb_file);
  41
  42 /* Minimum number of milliseconds between database compactions. */
  43 #define COMPACT_MIN_MSEC        (10 * 60 * 1000) /* 10 minutes. */
  44
  45 /* Minimum number of milliseconds between trying to compact the database if
  46  * compacting fails. */
  47 #define COMPACT_RETRY_MSEC      (60 * 1000)      /* 1 minute. */
  48
  49 /* A transaction being converted to JSON for writing to a file. */
  50 struct ovsdb_file_txn {
  51     struct json *json;          /* JSON for the whole transaction. */
  52     struct json *table_json;    /* JSON for 'table''s transaction. */
  53     struct ovsdb_table *table;  /* Table described in 'table_json'.  */
  54 };
  55
  56 static void ovsdb_file_txn_init(struct ovsdb_file_txn *);
  57 static void ovsdb_file_txn_add_row(struct ovsdb_file_txn *,
  58                                    const struct ovsdb_row *old,
  59                                    const struct ovsdb_row *new,
  60                                    const unsigned long int *changed);
  61 static struct ovsdb_error *ovsdb_file_txn_commit(struct json *,
  62                                                  const char *comment,
  63                                                  bool durable,
  64                                                  struct ovsdb_log *);
  65
  66 static struct ovsdb_error *ovsdb_file_open__(const char *file_name,
  67                                              const struct ovsdb_schema *,
  68                                              bool read_only, struct ovsdb **,
  69                                              struct ovsdb_file **);
  70 static struct ovsdb_error *ovsdb_file_txn_from_json(
  71     struct ovsdb *, const struct json *, bool converting, struct ovsdb_txn **);
  72 static struct ovsdb_error *ovsdb_file_create(struct ovsdb *,
  73                                              struct ovsdb_log *,
  74                                              const char *file_name,
  75                                              unsigned int n_transactions,
  76                                              struct ovsdb_file **filep);
  77
  78 /* Opens database 'file_name' and stores a pointer to the new database in
  79  * '*dbp'.  If 'read_only' is false, then the database will be locked and
  80  * changes to the database will be written to disk.  If 'read_only' is true,
  81  * the database will not be locked and changes to the database will persist
  82  * only as long as the "struct ovsdb".
  83  *
  84  * If 'filep' is nonnull and 'read_only' is false, then on success sets
  85  * '*filep' to an ovsdb_file that represents the open file.  This ovsdb_file
  86  * persists until '*dbp' is destroyed.
  87  *
  88  * On success, returns NULL.  On failure, returns an ovsdb_error (which the
  89  * caller must destroy) and sets '*dbp' and '*filep' to NULL. */
  90 struct ovsdb_error *
  91 ovsdb_file_open(const char *file_name, bool read_only,
  92                 struct ovsdb **dbp, struct ovsdb_file **filep)
  93 {
  94     return ovsdb_file_open__(file_name, NULL, read_only, dbp, filep);
  95 }
  96
  97 /* Opens database 'file_name' with an alternate schema.  The specified 'schema'
  98  * is used to interpret the data in 'file_name', ignoring the schema actually
  99  * stored in the file.  Data in the file for tables or columns that do not
 100  * exist in 'schema' are ignored, but the ovsdb file format must otherwise be
 101  * observed, including column constraints.
 102  *
 103  * This function can be useful for upgrading or downgrading databases to
 104  * "almost-compatible" formats.
 105  *
 106  * The database will not be locked.  Changes to the database will persist only
 107  * as long as the "struct ovsdb".
 108  *
 109  * On success, stores a pointer to the new database in '*dbp' and returns a
 110  * null pointer.  On failure, returns an ovsdb_error (which the caller must
 111  * destroy) and sets '*dbp' to NULL. */
 112 struct ovsdb_error *
 113 ovsdb_file_open_as_schema(const char *file_name,
 114                           const struct ovsdb_schema *schema,
 115                           struct ovsdb **dbp)
 116 {
 117     return ovsdb_file_open__(file_name, schema, true, dbp, NULL);
 118 }
 119
 120 static struct ovsdb_error *
 121 ovsdb_file_open_log(const char *file_name, enum ovsdb_log_open_mode open_mode,
 122                     struct ovsdb_log **logp, struct ovsdb_schema **schemap)
 123 {
 124     struct ovsdb_schema *schema = NULL;
 125     struct ovsdb_log *log = NULL;
 126     struct ovsdb_error *error;
 127     struct json *json = NULL;
 128
 129     ovs_assert(logp || schemap);
 130
 131     error = ovsdb_log_open(file_name, open_mode, -1, &log);
 132     if (error) {
 133         goto error;
 134     }
 135
 136     error = ovsdb_log_read(log, &json);
 137     if (error) {
 138         goto error;
 139     } else if (!json) {
 140         error = ovsdb_io_error(EOF, "%s: database file contains no schema",
 141                                file_name);
 142         goto error;
 143     }
 144
 145     if (schemap) {
 146         error = ovsdb_schema_from_json(json, &schema);
 147         if (error) {
 148             error = ovsdb_wrap_error(error,
 149                                      "failed to parse \"%s\" as ovsdb schema",
 150                                      file_name);
 151             goto error;
 152         }
 153     }
 154     json_destroy(json);
 155
 156     if (logp) {
 157         *logp = log;
 158     } else {
 159         ovsdb_log_close(log);
 160     }
 161     if (schemap) {
 162         *schemap = schema;
 163     }
 164     return NULL;
 165
 166 error:
 167     ovsdb_log_close(log);
 168     json_destroy(json);
 169     if (logp) {
 170         *logp = NULL;
 171     }
 172     if (schemap) {
 173         *schemap = NULL;
 174     }
 175     return error;
 176 }
 177
 178 static struct ovsdb_error *
 179 ovsdb_file_open__(const char *file_name,
 180                   const struct ovsdb_schema *alternate_schema,
 181                   bool read_only, struct ovsdb **dbp,
 182                   struct ovsdb_file **filep)
 183 {
 184     enum ovsdb_log_open_mode open_mode;
 185     unsigned int n_transactions;
 186     struct ovsdb_schema *schema = NULL;
 187     struct ovsdb_error *error;
 188     struct ovsdb_log *log;
 189     struct json *json;
 190     struct ovsdb *db = NULL;
 191
 192     /* In read-only mode there is no ovsdb_file so 'filep' must be null. */
 193     ovs_assert(!(read_only && filep));
 194
 195     open_mode = read_only ? OVSDB_LOG_READ_ONLY : OVSDB_LOG_READ_WRITE;
 196     error = ovsdb_file_open_log(file_name, open_mode, &log,
 197                                 alternate_schema ? NULL : &schema);
 198     if (error) {
 199         goto error;
 200     }
 201
 202     db = ovsdb_create(schema ? schema : ovsdb_schema_clone(alternate_schema));
 203
 204     n_transactions = 0;
 205     while ((error = ovsdb_log_read(log, &json)) == NULL && json) {
 206         struct ovsdb_txn *txn;
 207
 208         error = ovsdb_file_txn_from_json(db, json, alternate_schema != NULL,
 209                                          &txn);
 210         json_destroy(json);
 211         if (error) {
 212             ovsdb_log_unread(log);
 213             break;
 214         }
 215
 216         n_transactions++;
 217         error = ovsdb_txn_commit(txn, false);
 218         if (error) {
 219             ovsdb_log_unread(log);
 220             break;
 221         }
 222     }
 223     if (error) {
 224         /* Log error but otherwise ignore it.  Probably the database just got
 225          * truncated due to power failure etc. and we should use its current
 226          * contents. */
 227         char *msg = ovsdb_error_to_string(error);
 228         VLOG_ERR("%s", msg);
 229         free(msg);
 230
 231         ovsdb_error_destroy(error);
 232     }
 233
 234     if (!read_only) {
 235         struct ovsdb_file *file;
 236
 237         error = ovsdb_file_create(db, log, file_name, n_transactions, &file);
 238         if (error) {
 239             goto error;
 240         }
 241         if (filep) {
 242             *filep = file;
 243         }
 244     } else {
 245         ovsdb_log_close(log);
 246     }
 247
 248     *dbp = db;
 249     return NULL;
 250
 251 error:
 252     *dbp = NULL;
 253     if (filep) {
 254         *filep = NULL;
 255     }
 256     ovsdb_destroy(db);
 257     ovsdb_log_close(log);
 258     return error;
 259 }
 260
 261 static struct ovsdb_error *
 262 ovsdb_file_update_row_from_json(struct ovsdb_row *row, bool converting,
 263                                 const struct json *json)
 264 {
 265     struct ovsdb_table_schema *schema = row->table->schema;
 266     struct ovsdb_error *error;
 267     struct shash_node *node;
 268
 269     if (json->type != JSON_OBJECT) {
 270         return ovsdb_syntax_error(json, NULL, "row must be JSON object");
 271     }
 272
 273     SHASH_FOR_EACH (node, json_object(json)) {
 274         const char *column_name = node->name;
 275         const struct ovsdb_column *column;
 276         struct ovsdb_datum datum;
 277
 278         column = ovsdb_table_schema_get_column(schema, column_name);
 279         if (!column) {
 280             if (converting) {
 281                 continue;
 282             }
 283             return ovsdb_syntax_error(json, "unknown column",
 284                                       "No column %s in table %s.",
 285                                       column_name, schema->name);
 286         }
 287
 288         error = ovsdb_datum_from_json(&datum, &column->type, node->data, NULL);
 289         if (error) {
 290             return error;
 291         }
 292         ovsdb_datum_swap(&row->fields[column->index], &datum);
 293         ovsdb_datum_destroy(&datum, &column->type);
 294     }
 295
 296     return NULL;
 297 }
 298
 299 static struct ovsdb_error *
 300 ovsdb_file_txn_row_from_json(struct ovsdb_txn *txn, struct ovsdb_table *table,
 301                              bool converting,
 302                              const struct uuid *row_uuid, struct json *json)
 303 {
 304     const struct ovsdb_row *row = ovsdb_table_get_row(table, row_uuid);
 305     if (json->type == JSON_NULL) {
 306         if (!row) {
 307             return ovsdb_syntax_error(NULL, NULL, "transaction deletes "
 308                                       "row "UUID_FMT" that does not exist",
 309                                       UUID_ARGS(row_uuid));
 310         }
 311         ovsdb_txn_row_delete(txn, row);
 312         return NULL;
 313     } else if (row) {
 314         return ovsdb_file_update_row_from_json(ovsdb_txn_row_modify(txn, row),
 315                                                converting, json);
 316     } else {
 317         struct ovsdb_error *error;
 318         struct ovsdb_row *new;
 319
 320         new = ovsdb_row_create(table);
 321         *ovsdb_row_get_uuid_rw(new) = *row_uuid;
 322         error = ovsdb_file_update_row_from_json(new, converting, json);
 323         if (error) {
 324             ovsdb_row_destroy(new);
 325         } else {
 326             ovsdb_txn_row_insert(txn, new);
 327         }
 328         return error;
 329     }
 330 }
 331
 332 static struct ovsdb_error *
 333 ovsdb_file_txn_table_from_json(struct ovsdb_txn *txn,
 334                                struct ovsdb_table *table,
 335                                bool converting, struct json *json)
 336 {
 337     struct shash_node *node;
 338
 339     if (json->type != JSON_OBJECT) {
 340         return ovsdb_syntax_error(json, NULL, "object expected");
 341     }
 342
 343     SHASH_FOR_EACH (node, json->u.object) {
 344         const char *uuid_string = node->name;
 345         struct json *txn_row_json = node->data;
 346         struct ovsdb_error *error;
 347         struct uuid row_uuid;
 348
 349         if (!uuid_from_string(&row_uuid, uuid_string)) {
 350             return ovsdb_syntax_error(json, NULL, "\"%s\" is not a valid UUID",
 351                                       uuid_string);
 352         }
 353
 354         error = ovsdb_file_txn_row_from_json(txn, table, converting,
 355                                              &row_uuid, txn_row_json);
 356         if (error) {
 357             return error;
 358         }
 359     }
 360
 361     return NULL;
 362 }
 363
 364 /* Converts 'json' to an ovsdb_txn for 'db', storing the new transaction in
 365  * '*txnp'.  Returns NULL if successful, otherwise an error.
 366  *
 367  * If 'converting' is true, then unknown table and column names are ignored
 368  * (which can ease upgrading and downgrading schemas); otherwise, they are
 369  * treated as errors. */
 370 static struct ovsdb_error *
 371 ovsdb_file_txn_from_json(struct ovsdb *db, const struct json *json,
 372                          bool converting, struct ovsdb_txn **txnp)
 373 {
 374     struct ovsdb_error *error;
 375     struct shash_node *node;
 376     struct ovsdb_txn *txn;
 377
 378     *txnp = NULL;
 379
 380     if (json->type != JSON_OBJECT) {
 381         return ovsdb_syntax_error(json, NULL, "object expected");
 382     }
 383
 384     txn = ovsdb_txn_create(db);
 385     SHASH_FOR_EACH (node, json->u.object) {
 386         const char *table_name = node->name;
 387         struct json *node_json = node->data;
 388         struct ovsdb_table *table;
 389
 390         table = shash_find_data(&db->tables, table_name);
 391         if (!table) {
 392             if (!strcmp(table_name, "_date")
 393                 && node_json->type == JSON_INTEGER) {
 394                 continue;
 395             } else if (!strcmp(table_name, "_comment") || converting) {
 396                 continue;
 397             }
 398
 399             error = ovsdb_syntax_error(json, "unknown table",
 400                                        "No table named %s.", table_name);
 401             goto error;
 402         }
 403
 404         error = ovsdb_file_txn_table_from_json(txn, table, converting,
 405                                                node_json);
 406         if (error) {
 407             goto error;
 408         }
 409     }
 410     *txnp = txn;
 411     return NULL;
 412
 413 error:
 414     ovsdb_txn_abort(txn);
 415     return error;
 416 }
 417
 418 static struct ovsdb_error *
 419 ovsdb_file_save_copy__(const char *file_name, int locking,
 420                        const char *comment, const struct ovsdb *db,
 421                        struct ovsdb_log **logp)
 422 {
 423     const struct shash_node *node;
 424     struct ovsdb_file_txn ftxn;
 425     struct ovsdb_error *error;
 426     struct ovsdb_log *log;
 427     struct json *json;
 428
 429     error = ovsdb_log_open(file_name, OVSDB_LOG_CREATE, locking, &log);
 430     if (error) {
 431         return error;
 432     }
 433
 434     /* Write schema. */
 435     json = ovsdb_schema_to_json(db->schema);
 436     error = ovsdb_log_write(log, json);
 437     json_destroy(json);
 438     if (error) {
 439         goto exit;
 440     }
 441
 442     /* Write data. */
 443     ovsdb_file_txn_init(&ftxn);
 444     SHASH_FOR_EACH (node, &db->tables) {
 445         const struct ovsdb_table *table = node->data;
 446         const struct ovsdb_row *row;
 447
 448         HMAP_FOR_EACH (row, hmap_node, &table->rows) {
 449             ovsdb_file_txn_add_row(&ftxn, NULL, row, NULL);
 450         }
 451     }
 452     error = ovsdb_file_txn_commit(ftxn.json, comment, true, log);
 453
 454 exit:
 455     if (logp) {
 456         if (!error) {
 457             *logp = log;
 458             log = NULL;
 459         } else {
 460             *logp = NULL;
 461         }
 462     }
 463     ovsdb_log_close(log);
 464     if (error) {
 465         remove(file_name);
 466     }
 467     return error;
 468 }
 469
 470 /* Saves a snapshot of 'db''s current contents as 'file_name'.  If 'comment' is
 471  * nonnull, then it is added along with the data contents and can be viewed
 472  * with "ovsdb-tool show-log".
 473  *
 474  * 'locking' is passed along to ovsdb_log_open() untouched. */
 475 struct ovsdb_error *
 476 ovsdb_file_save_copy(const char *file_name, int locking,
 477                      const char *comment, const struct ovsdb *db)
 478 {
 479     return ovsdb_file_save_copy__(file_name, locking, comment, db, NULL);
 480 }
 481
 482 /* Opens database 'file_name', reads its schema, and closes it.  On success,
 483  * stores the schema into '*schemap' and returns NULL; the caller then owns the
 484  * schema.  On failure, returns an ovsdb_error (which the caller must destroy)
 485  * and sets '*dbp' to NULL. */
 486 struct ovsdb_error *
 487 ovsdb_file_read_schema(const char *file_name, struct ovsdb_schema **schemap)
 488 {
 489     ovs_assert(schemap != NULL);
 490     return ovsdb_file_open_log(file_name, OVSDB_LOG_READ_ONLY, NULL, schemap);
 491 }
 492 \f
 493 /* Replica implementation. */
 494
 495 struct ovsdb_file {
 496     struct ovsdb_replica replica;
 497     struct ovsdb *db;
 498     struct ovsdb_log *log;
 499     char *file_name;
 500     long long int last_compact;
 501     long long int next_compact;
 502     unsigned int n_transactions;
 503 };
 504
 505 static const struct ovsdb_replica_class ovsdb_file_class;
 506
 507 static struct ovsdb_error *
 508 ovsdb_file_create(struct ovsdb *db, struct ovsdb_log *log,
 509                   const char *file_name,
 510                   unsigned int n_transactions,
 511                   struct ovsdb_file **filep)
 512 {
 513     struct ovsdb_file *file;
 514     char *deref_name;
 515     char *abs_name;
 516
 517     /* Use the absolute name of the file because ovsdb-server opens its
 518      * database before daemonize() chdirs to "/". */
 519     deref_name = follow_symlinks(file_name);
 520     abs_name = abs_file_name(NULL, deref_name);
 521     free(deref_name);
 522     if (!abs_name) {
 523         *filep = NULL;
 524         return ovsdb_io_error(0, "could not determine current "
 525                               "working directory");
 526     }
 527
 528     file = xmalloc(sizeof *file);
 529     ovsdb_replica_init(&file->replica, &ovsdb_file_class);
 530     file->db = db;
 531     file->log = log;
 532     file->file_name = abs_name;
 533     file->last_compact = time_msec();
 534     file->next_compact = file->last_compact + COMPACT_MIN_MSEC;
 535     file->n_transactions = n_transactions;
 536     ovsdb_add_replica(db, &file->replica);
 537
 538     *filep = file;
 539     return NULL;
 540 }
 541
 542 static struct ovsdb_file *
 543 ovsdb_file_cast(struct ovsdb_replica *replica)
 544 {
 545     ovs_assert(replica->class == &ovsdb_file_class);
 546     return CONTAINER_OF(replica, struct ovsdb_file, replica);
 547 }
 548
 549 static bool
 550 ovsdb_file_change_cb(const struct ovsdb_row *old,
 551                      const struct ovsdb_row *new,
 552                      const unsigned long int *changed,
 553                      void *ftxn_)
 554 {
 555     struct ovsdb_file_txn *ftxn = ftxn_;
 556     ovsdb_file_txn_add_row(ftxn, old, new, changed);
 557     return true;
 558 }
 559
 560 static struct ovsdb_error *
 561 ovsdb_file_commit(struct ovsdb_replica *replica,
 562                   const struct ovsdb_txn *txn, bool durable)
 563 {
 564     struct ovsdb_file *file = ovsdb_file_cast(replica);
 565     struct ovsdb_file_txn ftxn;
 566     struct ovsdb_error *error;
 567
 568     ovsdb_file_txn_init(&ftxn);
 569     ovsdb_txn_for_each_change(txn, ovsdb_file_change_cb, &ftxn);
 570     if (!ftxn.json) {
 571         /* Nothing to commit. */
 572         return NULL;
 573     }
 574
 575     error = ovsdb_file_txn_commit(ftxn.json, ovsdb_txn_get_comment(txn),
 576                                   durable, file->log);
 577     if (error) {
 578         return error;
 579     }
 580     file->n_transactions++;
 581
 582     /* If it has been at least COMPACT_MIN_MSEC ms since the last time we
 583      * compacted (or at least COMPACT_RETRY_MSEC ms since the last time we
 584      * tried), and if there are at least 100 transactions in the database, and
 585      * if the database is at least 10 MB, then compact the database. */
 586     if (time_msec() >= file->next_compact
 587         && file->n_transactions >= 100
 588         && ovsdb_log_get_offset(file->log) >= 10 * 1024 * 1024)
 589     {
 590         error = ovsdb_file_compact(file);
 591         if (error) {
 592             char *s = ovsdb_error_to_string(error);
 593             ovsdb_error_destroy(error);
 594             VLOG_WARN("%s: compacting database failed (%s), retrying in "
 595                       "%d seconds",
 596                       file->file_name, s, COMPACT_RETRY_MSEC / 1000);
 597             free(s);
 598
 599             file->next_compact = time_msec() + COMPACT_RETRY_MSEC;
 600         }
 601     }
 602
 603     return NULL;
 604 }
 605
 606 struct ovsdb_error *
 607 ovsdb_file_compact(struct ovsdb_file *file)
 608 {
 609     struct ovsdb_log *new_log = NULL;
 610     struct lockfile *tmp_lock = NULL;
 611     struct ovsdb_error *error;
 612     char *tmp_name = NULL;
 613     char *comment = NULL;
 614     int retval;
 615
 616     comment = xasprintf("compacting database online "
 617                         "(%.3f seconds old, %u transactions, %llu bytes)",
 618                         (time_wall_msec() - file->last_compact) / 1000.0,
 619                         file->n_transactions,
 620                         (unsigned long long) ovsdb_log_get_offset(file->log));
 621     VLOG_INFO("%s: %s", file->file_name, comment);
 622
 623     /* Commit the old version, so that we can be assured that we'll eventually
 624      * have either the old or the new version. */
 625     error = ovsdb_log_commit(file->log);
 626     if (error) {
 627         goto exit;
 628     }
 629
 630     /* Lock temporary file. */
 631     tmp_name = xasprintf("%s.tmp", file->file_name);
 632     retval = lockfile_lock(tmp_name, &tmp_lock);
 633     if (retval) {
 634         error = ovsdb_io_error(retval, "could not get lock on %s", tmp_name);
 635         goto exit;
 636     }
 637
 638     /* Remove temporary file.  (It might not exist.) */
 639     if (unlink(tmp_name) < 0 && errno != ENOENT) {
 640         error = ovsdb_io_error(errno, "failed to remove %s", tmp_name);
 641         goto exit;
 642     }
 643
 644     /* Save a copy. */
 645     error = ovsdb_file_save_copy__(tmp_name, false, comment, file->db,
 646                                    &new_log);
 647     if (error) {
 648         goto exit;
 649     }
 650
 651     /* Replace original by temporary. */
 652     if (rename(tmp_name, file->file_name)) {
 653         error = ovsdb_io_error(errno, "failed to rename \"%s\" to \"%s\"",
 654                                tmp_name, file->file_name);
 655         goto exit;
 656     }
 657     fsync_parent_dir(file->file_name);
 658
 659 exit:
 660     if (!error) {
 661         ovsdb_log_close(file->log);
 662         file->log = new_log;
 663         file->last_compact = time_msec();
 664         file->next_compact = file->last_compact + COMPACT_MIN_MSEC;
 665         file->n_transactions = 1;
 666     } else {
 667         ovsdb_log_close(new_log);
 668         if (tmp_lock) {
 669             unlink(tmp_name);
 670         }
 671     }
 672
 673     lockfile_unlock(tmp_lock);
 674     free(tmp_name);
 675     free(comment);
 676
 677     return error;
 678 }
 679
 680 static void
 681 ovsdb_file_destroy(struct ovsdb_replica *replica)
 682 {
 683     struct ovsdb_file *file = ovsdb_file_cast(replica);
 684
 685     ovsdb_log_close(file->log);
 686     free(file->file_name);
 687     free(file);
 688 }
 689
 690 static const struct ovsdb_replica_class ovsdb_file_class = {
 691     ovsdb_file_commit,
 692     ovsdb_file_destroy
 693 };
 694 \f
 695 static void
 696 ovsdb_file_txn_init(struct ovsdb_file_txn *ftxn)
 697 {
 698     ftxn->json = NULL;
 699     ftxn->table_json = NULL;
 700     ftxn->table = NULL;
 701 }
 702
 703 static void
 704 ovsdb_file_txn_add_row(struct ovsdb_file_txn *ftxn,
 705                        const struct ovsdb_row *old,
 706                        const struct ovsdb_row *new,
 707                        const unsigned long int *changed)
 708 {
 709     struct json *row;
 710
 711     if (!new) {
 712         row = json_null_create();
 713     } else {
 714         struct shash_node *node;
 715
 716         row = old ? NULL : json_object_create();
 717         SHASH_FOR_EACH (node, &new->table->schema->columns) {
 718             const struct ovsdb_column *column = node->data;
 719             const struct ovsdb_type *type = &column->type;
 720             unsigned int idx = column->index;
 721
 722             if (idx != OVSDB_COL_UUID && column->persistent
 723                 && (old
 724                     ? bitmap_is_set(changed, idx)
 725                     : !ovsdb_datum_is_default(&new->fields[idx], type)))
 726             {
 727                 if (!row) {
 728                     row = json_object_create();
 729                 }
 730                 json_object_put(row, column->name,
 731                                 ovsdb_datum_to_json(&new->fields[idx], type));
 732             }
 733         }
 734     }
 735
 736     if (row) {
 737         struct ovsdb_table *table = new ? new->table : old->table;
 738         char uuid[UUID_LEN + 1];
 739
 740         if (table != ftxn->table) {
 741             /* Create JSON object for transaction overall. */
 742             if (!ftxn->json) {
 743                 ftxn->json = json_object_create();
 744             }
 745
 746             /* Create JSON object for transaction on this table. */
 747             ftxn->table_json = json_object_create();
 748             ftxn->table = table;
 749             json_object_put(ftxn->json, table->schema->name, ftxn->table_json);
 750         }
 751
 752         /* Add row to transaction for this table. */
 753         snprintf(uuid, sizeof uuid,
 754                  UUID_FMT, UUID_ARGS(ovsdb_row_get_uuid(new ? new : old)));
 755         json_object_put(ftxn->table_json, uuid, row);
 756     }
 757 }
 758
 759 static struct ovsdb_error *
 760 ovsdb_file_txn_commit(struct json *json, const char *comment,
 761                       bool durable, struct ovsdb_log *log)
 762 {
 763     struct ovsdb_error *error;
 764
 765     if (!json) {
 766         json = json_object_create();
 767     }
 768     if (comment) {
 769         json_object_put_string(json, "_comment", comment);
 770     }
 771     json_object_put(json, "_date", json_integer_create(time_wall_msec()));
 772
 773     error = ovsdb_log_write(log, json);
 774     json_destroy(json);
 775     if (error) {
 776         return ovsdb_wrap_error(error, "writing transaction failed");
 777     }
 778
 779     if (durable) {
 780         error = ovsdb_log_commit(log);
 781         if (error) {
 782             return ovsdb_wrap_error(error, "committing transaction failed");
 783         }
 784     }
 785
 786     return NULL;
 787 }