X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fovsdb-idl.c;h=19ae16fe54d0282b6bf3ae249dea6cbbce60db8e;hb=ece72d2415c62548751ba7276e5ca5e2dde11c04;hp=448f9c94424e35030f9d4794c7133c476db831b7;hpb=ef73f86cd4f7ec0cd2d3f9526167a0d0f6be4f63;p=sliver-openvswitch.git diff --git a/lib/ovsdb-idl.c b/lib/ovsdb-idl.c index 448f9c944..19ae16fe5 100644 --- a/lib/ovsdb-idl.c +++ b/lib/ovsdb-idl.c @@ -1,4 +1,4 @@ -/* Copyright (c) 2009, 2010 Nicira Networks. +/* Copyright (c) 2009, 2010, 2011 Nicira Networks. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -71,6 +71,12 @@ struct ovsdb_idl { unsigned int last_monitor_request_seqno; unsigned int change_seqno; + /* Database locking. */ + char *lock_name; /* Name of lock we need, NULL if none. */ + bool has_lock; /* Has db server told us we have the lock? */ + bool is_lock_contended; /* Has db server told us we can't get lock? */ + struct json *lock_request_id; /* JSON-RPC ID of in-flight lock request. */ + /* Transaction support. */ struct ovsdb_idl_txn *txn; struct hmap outstanding_txns; @@ -85,6 +91,7 @@ struct ovsdb_idl_txn { char *error; bool dry_run; struct ds comment; + unsigned int commit_seqno; /* Increments. */ char *inc_table; @@ -94,7 +101,7 @@ struct ovsdb_idl_txn { int64_t inc_new_value; /* Inserted rows. */ - struct hmap inserted_rows; + struct hmap inserted_rows; /* Contains "struct ovsdb_idl_txn_insert"s. */ }; struct ovsdb_idl_txn_insert { @@ -136,6 +143,14 @@ static void ovsdb_idl_txn_abort_all(struct ovsdb_idl *); static bool ovsdb_idl_txn_process_reply(struct ovsdb_idl *, const struct jsonrpc_msg *msg); +static void ovsdb_idl_send_lock_request(struct ovsdb_idl *); +static void ovsdb_idl_send_unlock_request(struct ovsdb_idl *); +static void ovsdb_idl_parse_lock_reply(struct ovsdb_idl *, + const struct json *); +static void ovsdb_idl_parse_lock_notify(struct ovsdb_idl *, + const struct json *params, + bool new_has_lock); + /* Creates and returns a connection to database 'remote', which should be in a * form acceptable to jsonrpc_session_open(). The connection will maintain an * in-memory replica of the remote database whose schema is described by @@ -213,6 +228,8 @@ ovsdb_idl_destroy(struct ovsdb_idl *idl) shash_destroy(&idl->table_by_name); free(idl->tables); json_destroy(idl->monitor_request_id); + free(idl->lock_name); + json_destroy(idl->lock_request_id); free(idl); } } @@ -256,7 +273,9 @@ ovsdb_idl_clear(struct ovsdb_idl *idl) /* Processes a batch of messages from the database server on 'idl'. Returns * true if the database as seen through 'idl' changed, false if it did not * change. The initial fetch of the entire contents of the remote database is - * considered to be one kind of change. + * considered to be one kind of change. If 'idl' has been configured to + * acquire a database lock (with ovsdb_idl_set_lock()), then successfully + * acquiring the lock is also considered to be a change. * * When this function returns false, the client may continue to use any data * structures it obtained from 'idl' in the past. But when it returns true, @@ -282,7 +301,7 @@ ovsdb_idl_run(struct ovsdb_idl *idl) assert(!idl->txn); jsonrpc_session_run(idl->session); for (i = 0; jsonrpc_session_is_connected(idl->session) && i < 50; i++) { - struct jsonrpc_msg *msg, *reply; + struct jsonrpc_msg *msg; unsigned int seqno; seqno = jsonrpc_session_get_seqno(idl->session); @@ -290,6 +309,9 @@ ovsdb_idl_run(struct ovsdb_idl *idl) idl->last_monitor_request_seqno = seqno; ovsdb_idl_txn_abort_all(idl); ovsdb_idl_send_monitor_request(idl); + if (idl->lock_name) { + ovsdb_idl_send_lock_request(idl); + } break; } @@ -298,25 +320,38 @@ ovsdb_idl_run(struct ovsdb_idl *idl) break; } - reply = NULL; if (msg->type == JSONRPC_NOTIFY - && !strcmp(msg->method, "update") - && msg->params->type == JSON_ARRAY - && msg->params->u.array.n == 2 - && msg->params->u.array.elems[0]->type == JSON_NULL) { + && !strcmp(msg->method, "update") + && msg->params->type == JSON_ARRAY + && msg->params->u.array.n == 2 + && msg->params->u.array.elems[0]->type == JSON_NULL) { + /* Database contents changed. */ ovsdb_idl_parse_update(idl, msg->params->u.array.elems[1]); } else if (msg->type == JSONRPC_REPLY && idl->monitor_request_id && json_equal(idl->monitor_request_id, msg->id)) { + /* Reply to our "monitor" request. */ idl->change_seqno++; json_destroy(idl->monitor_request_id); idl->monitor_request_id = NULL; ovsdb_idl_clear(idl); ovsdb_idl_parse_update(idl, msg->result); } else if (msg->type == JSONRPC_REPLY - && msg->id && msg->id->type == JSON_STRING + && idl->lock_request_id + && json_equal(idl->lock_request_id, msg->id)) { + /* Reply to our "lock" request. */ + ovsdb_idl_parse_lock_reply(idl, msg->result); + } else if (msg->type == JSONRPC_NOTIFY + && !strcmp(msg->method, "locked")) { + /* We got our lock. */ + ovsdb_idl_parse_lock_notify(idl, msg->params, true); + } else if (msg->type == JSONRPC_NOTIFY + && !strcmp(msg->method, "stolen")) { + /* Someone else stole our lock. */ + ovsdb_idl_parse_lock_notify(idl, msg->params, false); + } else if (msg->type == JSONRPC_REPLY && msg->id->type == JSON_STRING && !strcmp(msg->id->u.string, "echo")) { - /* It's a reply to our echo request. Ignore it. */ + /* Reply to our echo request. Ignore it. */ } else if ((msg->type == JSONRPC_ERROR || msg->type == JSONRPC_REPLY) && ovsdb_idl_txn_process_reply(idl, msg)) { @@ -329,9 +364,6 @@ ovsdb_idl_run(struct ovsdb_idl *idl) jsonrpc_session_get_name(idl->session), jsonrpc_msg_type_to_string(msg->type)); } - if (reply) { - jsonrpc_session_send(idl->session, reply); - } jsonrpc_msg_destroy(msg); } @@ -1080,8 +1112,13 @@ const struct ovsdb_datum * ovsdb_idl_read(const struct ovsdb_idl_row *row, const struct ovsdb_idl_column *column) { - const struct ovsdb_idl_table_class *class = row->table->class; - size_t column_idx = column - class->columns; + const struct ovsdb_idl_table_class *class; + size_t column_idx; + + assert(!ovsdb_idl_row_is_synthetic(row)); + + class = row->table->class; + column_idx = column - class->columns; assert(row->new != NULL); assert(column_idx < class->n_columns); @@ -1113,6 +1150,15 @@ ovsdb_idl_get(const struct ovsdb_idl_row *row, return ovsdb_idl_read(row, column); } + +/* Returns false if 'row' was obtained from the IDL, true if it was initialized + * to all-zero-bits by some other entity. If 'row' was set up some other way + * then the return value is indeterminate. */ +bool +ovsdb_idl_row_is_synthetic(const struct ovsdb_idl_row *row) +{ + return row->table == NULL; +} /* Transactions. */ @@ -1123,6 +1169,8 @@ const char * ovsdb_idl_txn_status_to_string(enum ovsdb_idl_txn_status status) { switch (status) { + case TXN_UNCOMMITTED: + return "uncommitted"; case TXN_UNCHANGED: return "unchanged"; case TXN_INCOMPLETE: @@ -1131,8 +1179,12 @@ ovsdb_idl_txn_status_to_string(enum ovsdb_idl_txn_status status) return "aborted"; case TXN_SUCCESS: return "success"; - case TXN_TRY_AGAIN: - return "try again"; + case TXN_AGAIN_WAIT: + return "wait then try again"; + case TXN_AGAIN_NOW: + return "try again now"; + case TXN_NOT_LOCKED: + return "not locked"; case TXN_ERROR: return "error"; } @@ -1149,10 +1201,11 @@ ovsdb_idl_txn_create(struct ovsdb_idl *idl) txn->request_id = NULL; txn->idl = idl; hmap_init(&txn->txn_rows); - txn->status = TXN_INCOMPLETE; + txn->status = TXN_UNCOMMITTED; txn->error = NULL; txn->dry_run = false; ds_init(&txn->comment); + txn->commit_seqno = txn->idl->change_seqno; txn->inc_table = NULL; txn->inc_column = NULL; @@ -1222,7 +1275,7 @@ ovsdb_idl_txn_destroy(struct ovsdb_idl_txn *txn) void ovsdb_idl_txn_wait(const struct ovsdb_idl_txn *txn) { - if (txn->status != TXN_INCOMPLETE) { + if (txn->status != TXN_UNCOMMITTED && txn->status != TXN_INCOMPLETE) { poll_immediate_wake(); } } @@ -1360,9 +1413,24 @@ ovsdb_idl_txn_commit(struct ovsdb_idl_txn *txn) return txn->status; } + /* If we need a lock but don't have it, give up quickly. */ + if (txn->idl->lock_name && !ovsdb_idl_has_lock(txn->idl)) { + txn->status = TXN_NOT_LOCKED; + ovsdb_idl_txn_disassemble(txn); + return txn->status; + } + operations = json_array_create_1( json_string_create(txn->idl->class->database)); + /* Assert that we have the required lock (avoiding a race). */ + if (txn->idl->lock_name) { + struct json *op = json_object_create(); + json_array_add(operations, op); + json_object_put_string(op, "op", "assert"); + json_object_put_string(op, "lock", txn->idl->lock_name); + } + /* Add prerequisites and declarations of new rows. */ HMAP_FOR_EACH (row, txn_node, &txn->txn_rows) { /* XXX check that deleted rows exist even if no prereqs? */ @@ -1399,16 +1467,18 @@ ovsdb_idl_txn_commit(struct ovsdb_idl_txn *txn) HMAP_FOR_EACH (row, txn_node, &txn->txn_rows) { const struct ovsdb_idl_table_class *class = row->table->class; - if (row->old == row->new) { - continue; - } else if (!row->new) { - struct json *op = json_object_create(); - json_object_put_string(op, "op", "delete"); - json_object_put_string(op, "table", class->name); - json_object_put(op, "where", where_uuid_equals(&row->uuid)); - json_array_add(operations, op); - any_updates = true; - } else { + if (!row->new) { + if (class->is_root) { + struct json *op = json_object_create(); + json_object_put_string(op, "op", "delete"); + json_object_put_string(op, "table", class->name); + json_object_put(op, "where", where_uuid_equals(&row->uuid)); + json_array_add(operations, op); + any_updates = true; + } else { + /* Let ovsdb-server decide whether to really delete it. */ + } + } else if (row->old != row->new) { struct json *row_json; struct json *op; size_t idx; @@ -1421,6 +1491,8 @@ ovsdb_idl_txn_commit(struct ovsdb_idl_txn *txn) } else { struct ovsdb_idl_txn_insert *insert; + any_updates = true; + json_object_put(op, "uuid-name", json_string_create_nocopy( uuid_name_from_uuid(&row->uuid))); @@ -1441,22 +1513,29 @@ ovsdb_idl_txn_commit(struct ovsdb_idl_txn *txn) &class->columns[idx]; if (row->old - ? !ovsdb_datum_equals(&row->old[idx], &row->new[idx], - &column->type) - : !ovsdb_datum_is_default(&row->new[idx], + || !ovsdb_datum_is_default(&row->new[idx], &column->type)) { json_object_put(row_json, column->name, substitute_uuids( ovsdb_datum_to_json(&row->new[idx], &column->type), txn)); + + /* If anything really changed, consider it an update. + * We can't suppress not-really-changed values earlier + * or transactions would become nonatomic (see the big + * comment inside ovsdb_idl_txn_write()). */ + if (!any_updates && row->old && + !ovsdb_datum_equals(&row->old[idx], &row->new[idx], + &column->type)) { + any_updates = true; + } } } } if (!row->old || !shash_is_empty(json_object(row_json))) { json_array_add(operations, op); - any_updates = true; } else { json_destroy(op); } @@ -1515,8 +1594,9 @@ ovsdb_idl_txn_commit(struct ovsdb_idl_txn *txn) "transact", operations, &txn->request_id))) { hmap_insert(&txn->idl->outstanding_txns, &txn->hmap_node, json_hash(txn->request_id, 0)); + txn->status = TXN_INCOMPLETE; } else { - txn->status = TXN_TRY_AGAIN; + txn->status = TXN_AGAIN_WAIT; } ovsdb_idl_txn_disassemble(txn); @@ -1552,7 +1632,7 @@ void ovsdb_idl_txn_abort(struct ovsdb_idl_txn *txn) { ovsdb_idl_txn_disassemble(txn); - if (txn->status == TXN_INCOMPLETE) { + if (txn->status == TXN_UNCOMMITTED || txn->status == TXN_INCOMPLETE) { txn->status = TXN_ABORTED; } } @@ -1623,21 +1703,50 @@ ovsdb_idl_txn_complete(struct ovsdb_idl_txn *txn, * been disabled (by calling ovsdb_idl_omit()). * * Usually this function is used indirectly through one of the "set" functions - * generated by ovsdb-idlc. */ + * generated by ovsdb-idlc. + * + * Takes ownership of what 'datum' points to (and in some cases destroys that + * data before returning) but makes a copy of 'datum' itself. (Commonly + * 'datum' is on the caller's stack.) */ void ovsdb_idl_txn_write(const struct ovsdb_idl_row *row_, const struct ovsdb_idl_column *column, struct ovsdb_datum *datum) { struct ovsdb_idl_row *row = (struct ovsdb_idl_row *) row_; - const struct ovsdb_idl_table_class *class = row->table->class; - size_t column_idx = column - class->columns; + const struct ovsdb_idl_table_class *class; + size_t column_idx; + + if (ovsdb_idl_row_is_synthetic(row)) { + return; + } + + class = row->table->class; + column_idx = column - class->columns; assert(row->new != NULL); assert(column_idx < class->n_columns); assert(row->old == NULL || row->table->modes[column_idx] & OVSDB_IDL_MONITOR); + /* If this is a write-only column and the datum being written is the same + * as the one already there, just skip the update entirely. This is worth + * optimizing because we have a lot of columns that get periodically + * refreshed into the database but don't actually change that often. + * + * We don't do this for read/write columns because that would break + * atomicity of transactions--some other client might have written a + * different value in that column since we read it. (But if a whole + * transaction only does writes of existing values, without making any real + * changes, we will drop the whole transaction later in + * ovsdb_idl_txn_commit().) */ + if (row->table->modes[column_idx] == OVSDB_IDL_MONITOR + && ovsdb_datum_equals(ovsdb_idl_read(row, column), + datum, &column->type)) { + ovsdb_datum_destroy(datum, &column->type); + return; + } + if (hmap_node_is_null(&row->txn_node)) { hmap_insert(&row->table->idl->txn->txn_rows, &row->txn_node, uuid_hash(&row->uuid)); @@ -1662,7 +1771,9 @@ ovsdb_idl_txn_write(const struct ovsdb_idl_row *row_, * prerequisite to completing the transaction. That is, if 'column' in 'row_' * changed (or if 'row_' was deleted) between the time that the IDL originally * read its contents and the time that the transaction commits, then the - * transaction aborts and ovsdb_idl_txn_commit() returns TXN_TRY_AGAIN. + * transaction aborts and ovsdb_idl_txn_commit() returns TXN_AGAIN_WAIT or + * TXN_AGAIN_NOW (depending on whether the database change has already been + * received). * * The intention is that, to ensure that no transaction commits based on dirty * reads, an application should call ovsdb_idl_txn_verify() on each data item @@ -1689,10 +1800,19 @@ ovsdb_idl_txn_verify(const struct ovsdb_idl_row *row_, const struct ovsdb_idl_column *column) { struct ovsdb_idl_row *row = (struct ovsdb_idl_row *) row_; - const struct ovsdb_idl_table_class *class = row->table->class; - size_t column_idx = column - class->columns; + const struct ovsdb_idl_table_class *class; + size_t column_idx; + + if (ovsdb_idl_row_is_synthetic(row)) { + return; + } + + class = row->table->class; + column_idx = column - class->columns; assert(row->new != NULL); + assert(row->old == NULL || + row->table->modes[column_idx] & OVSDB_IDL_MONITOR); if (!row->old || (row->written && bitmap_is_set(row->written, column_idx))) { return; @@ -1720,6 +1840,10 @@ ovsdb_idl_txn_delete(const struct ovsdb_idl_row *row_) { struct ovsdb_idl_row *row = (struct ovsdb_idl_row *) row_; + if (ovsdb_idl_row_is_synthetic(row)) { + return; + } + assert(row->new != NULL); if (!row->old) { ovsdb_idl_row_unparse(row); @@ -1777,7 +1901,7 @@ ovsdb_idl_txn_abort_all(struct ovsdb_idl *idl) struct ovsdb_idl_txn *txn; HMAP_FOR_EACH (txn, hmap_node, &idl->outstanding_txns) { - ovsdb_idl_txn_complete(txn, TXN_TRY_AGAIN); + ovsdb_idl_txn_complete(txn, TXN_AGAIN_WAIT); } } @@ -1923,6 +2047,7 @@ ovsdb_idl_txn_process_reply(struct ovsdb_idl *idl, struct json_array *ops = &msg->result->u.array; int hard_errors = 0; int soft_errors = 0; + int lock_errors = 0; size_t i; for (i = 0; i < ops->n; i++) { @@ -1940,6 +2065,8 @@ ovsdb_idl_txn_process_reply(struct ovsdb_idl *idl, if (error->type == JSON_STRING) { if (!strcmp(error->u.string, "timed out")) { soft_errors++; + } else if (!strcmp(error->u.string, "not owner")) { + lock_errors++; } else if (strcmp(error->u.string, "aborted")) { hard_errors++; ovsdb_idl_txn_set_error_json(txn, op); @@ -1959,7 +2086,7 @@ ovsdb_idl_txn_process_reply(struct ovsdb_idl *idl, } } - if (!soft_errors && !hard_errors) { + if (!soft_errors && !hard_errors && !lock_errors) { struct ovsdb_idl_txn_insert *insert; if (txn->inc_table && !ovsdb_idl_txn_process_inc_reply(txn, ops)) { @@ -1974,7 +2101,10 @@ ovsdb_idl_txn_process_reply(struct ovsdb_idl *idl, } status = (hard_errors ? TXN_ERROR - : soft_errors ? TXN_TRY_AGAIN + : lock_errors ? TXN_NOT_LOCKED + : soft_errors ? (txn->commit_seqno == idl->change_seqno + ? TXN_AGAIN_WAIT + : TXN_AGAIN_NOW) : TXN_SUCCESS); } @@ -1995,4 +2125,139 @@ ovsdb_idl_txn_get_idl (struct ovsdb_idl_txn *txn) { return txn->idl; } + +/* If 'lock_name' is nonnull, configures 'idl' to obtain the named lock from + * the database server and to avoid modifying the database when the lock cannot + * be acquired (that is, when another client has the same lock). + * + * If 'lock_name' is NULL, drops the locking requirement and releases the + * lock. */ +void +ovsdb_idl_set_lock(struct ovsdb_idl *idl, const char *lock_name) +{ + assert(!idl->txn); + assert(hmap_is_empty(&idl->outstanding_txns)); + + if (idl->lock_name && (!lock_name || strcmp(lock_name, idl->lock_name))) { + /* Release previous lock. */ + ovsdb_idl_send_unlock_request(idl); + free(idl->lock_name); + idl->lock_name = NULL; + idl->is_lock_contended = false; + } + + if (lock_name && !idl->lock_name) { + /* Acquire new lock. */ + idl->lock_name = xstrdup(lock_name); + ovsdb_idl_send_lock_request(idl); + } +} + +/* Returns true if 'idl' is configured to obtain a lock and owns that lock. + * + * Locking and unlocking happens asynchronously from the database client's + * point of view, so the information is only useful for optimization (e.g. if + * the client doesn't have the lock then there's no point in trying to write to + * the database). */ +bool +ovsdb_idl_has_lock(const struct ovsdb_idl *idl) +{ + return idl->has_lock; +} + +/* Returns true if 'idl' is configured to obtain a lock but the database server + * has indicated that some other client already owns the requested lock. */ +bool +ovsdb_idl_is_lock_contended(const struct ovsdb_idl *idl) +{ + return idl->is_lock_contended; +} + +static void +ovsdb_idl_update_has_lock(struct ovsdb_idl *idl, bool new_has_lock) +{ + if (new_has_lock && !idl->has_lock) { + if (!idl->monitor_request_id) { + idl->change_seqno++; + } else { + /* We're waiting for a monitor reply, so don't signal that the + * database changed. The monitor reply will increment change_seqno + * anyhow. */ + } + idl->is_lock_contended = false; + } + idl->has_lock = new_has_lock; +} + +static void +ovsdb_idl_send_lock_request__(struct ovsdb_idl *idl, const char *method, + struct json **idp) +{ + ovsdb_idl_update_has_lock(idl, false); + + json_destroy(idl->lock_request_id); + idl->lock_request_id = NULL; + if (jsonrpc_session_is_connected(idl->session)) { + struct json *params; + + params = json_array_create_1(json_string_create(idl->lock_name)); + jsonrpc_session_send(idl->session, + jsonrpc_create_request(method, params, idp)); + } +} + +static void +ovsdb_idl_send_lock_request(struct ovsdb_idl *idl) +{ + ovsdb_idl_send_lock_request__(idl, "lock", &idl->lock_request_id); +} + +static void +ovsdb_idl_send_unlock_request(struct ovsdb_idl *idl) +{ + ovsdb_idl_send_lock_request__(idl, "unlock", NULL); +} + +static void +ovsdb_idl_parse_lock_reply(struct ovsdb_idl *idl, const struct json *result) +{ + bool got_lock; + + json_destroy(idl->lock_request_id); + idl->lock_request_id = NULL; + + if (result->type == JSON_OBJECT) { + const struct json *locked; + + locked = shash_find_data(json_object(result), "locked"); + got_lock = locked && locked->type == JSON_TRUE; + } else { + got_lock = false; + } + + ovsdb_idl_update_has_lock(idl, got_lock); + if (!got_lock) { + idl->is_lock_contended = true; + } +} + +static void +ovsdb_idl_parse_lock_notify(struct ovsdb_idl *idl, + const struct json *params, + bool new_has_lock) +{ + if (idl->lock_name + && params->type == JSON_ARRAY + && json_array(params)->n > 0 + && json_array(params)->elems[0]->type == JSON_STRING) { + const char *lock_name = json_string(json_array(params)->elems[0]); + + if (!strcmp(idl->lock_name, lock_name)) { + ovsdb_idl_update_has_lock(idl, new_has_lock); + if (!new_has_lock) { + idl->is_lock_contended = true; + } + } + } +}