-/* 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.
#include "util.h"
#include "vlog.h"
-VLOG_DEFINE_THIS_MODULE(ovsdb_idl)
+VLOG_DEFINE_THIS_MODULE(ovsdb_idl);
/* An arc from one idl_row to another. When row A contains a UUID that
* references row B, this is represented by an arc from A (the source) to B
const struct ovsdb_idl_class *class;
struct jsonrpc_session *session;
struct shash table_by_name;
- struct ovsdb_idl_table *tables;
+ struct ovsdb_idl_table *tables; /* Contains "struct ovsdb_idl_table *"s.*/
struct json *monitor_request_id;
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;
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
* 'class'. (Ordinarily 'class' is compiled from an OVSDB schema automatically
- * by ovsdb-idlc.) */
+ * by ovsdb-idlc.)
+ *
+ * If 'monitor_everything_by_default' is true, then everything in the remote
+ * database will be replicated by default. ovsdb_idl_omit() and
+ * ovsdb_idl_omit_alert() may be used to selectively drop some columns from
+ * monitoring.
+ *
+ * If 'monitor_everything_by_default' is false, then no columns or tables will
+ * be replicated by default. ovsdb_idl_add_column() and ovsdb_idl_add_table()
+ * must be used to choose some columns or tables to replicate.
+ */
struct ovsdb_idl *
-ovsdb_idl_create(const char *remote, const struct ovsdb_idl_class *class)
+ovsdb_idl_create(const char *remote, const struct ovsdb_idl_class *class,
+ bool monitor_everything_by_default)
{
struct ovsdb_idl *idl;
+ uint8_t default_mode;
size_t i;
+ default_mode = (monitor_everything_by_default
+ ? OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT
+ : 0);
+
idl = xzalloc(sizeof *idl);
idl->class = class;
idl->session = jsonrpc_session_open(remote);
shash_add_assert(&idl->table_by_name, tc->name, table);
table->class = tc;
table->modes = xmalloc(tc->n_columns);
- memset(table->modes, OVSDB_IDL_MODE_RW, tc->n_columns);
+ memset(table->modes, default_mode, tc->n_columns);
+ table->need_table = false;
shash_init(&table->columns);
for (j = 0; j < tc->n_columns; j++) {
const struct ovsdb_idl_column *column = &tc->columns[j];
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);
}
}
/* 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,
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);
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;
}
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) {
+ /* 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)) {
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);
}
{
jsonrpc_session_force_reconnect(idl->session);
}
-
-static void
-ovsdb_idl_set_mode(struct ovsdb_idl *idl,
- const struct ovsdb_idl_column *column,
- enum ovsdb_idl_mode mode)
+\f
+static unsigned char *
+ovsdb_idl_get_mode(struct ovsdb_idl *idl,
+ const struct ovsdb_idl_column *column)
{
size_t i;
+ assert(!idl->change_seqno);
+
for (i = 0; i < idl->class->n_tables; i++) {
const struct ovsdb_idl_table *table = &idl->tables[i];
const struct ovsdb_idl_table_class *tc = table->class;
if (column >= tc->columns && column < &tc->columns[tc->n_columns]) {
- unsigned char *modep = &table->modes[column - tc->columns];
- assert(*modep == OVSDB_IDL_MODE_RW || *modep == mode);
- *modep = mode;
- return;
+ return &table->modes[column - tc->columns];
}
}
NOT_REACHED();
}
-/* By default, 'idl' replicates all of the columns in the remote database, and
- * ovsdb_idl_run() returns true upon a change to any column in the database.
- * Call this function to avoid alerting ovsdb_idl_run()'s caller upon changes
- * to 'column'.
+static void
+add_ref_table(struct ovsdb_idl *idl, const struct ovsdb_base_type *base)
+{
+ if (base->type == OVSDB_TYPE_UUID && base->u.uuid.refTableName) {
+ struct ovsdb_idl_table *table;
+
+ table = shash_find_data(&idl->table_by_name,
+ base->u.uuid.refTableName);
+ if (table) {
+ table->need_table = true;
+ } else {
+ VLOG_WARN("%s IDL class missing referenced table %s",
+ idl->class->database, base->u.uuid.refTableName);
+ }
+ }
+}
+
+/* Turns on OVSDB_IDL_MONITOR and OVSDB_IDL_ALERT for 'column' in 'idl'. Also
+ * ensures that any tables referenced by 'column' will be replicated, even if
+ * no columns in that table are selected for replication (see
+ * ovsdb_idl_add_table() for more information).
*
- * This is useful for columns that a client treats as "write-only", that is, it
- * updates them but doesn't want to get alerted about its own updates. It also
- * won't be alerted about other clients' updates, so this is suitable only for
- * use by a client that "owns" a particular column.
+ * This function is only useful if 'monitor_everything_by_default' was false in
+ * the call to ovsdb_idl_create(). This function should be called between
+ * ovsdb_idl_create() and the first call to ovsdb_idl_run().
+ */
+void
+ovsdb_idl_add_column(struct ovsdb_idl *idl,
+ const struct ovsdb_idl_column *column)
+{
+ *ovsdb_idl_get_mode(idl, column) = OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT;
+ add_ref_table(idl, &column->type.key);
+ add_ref_table(idl, &column->type.value);
+}
+
+/* Ensures that the table with class 'tc' will be replicated on 'idl' even if
+ * no columns are selected for replication. This can be useful because it
+ * allows 'idl' to keep track of what rows in the table actually exist, which
+ * in turn allows columns that reference the table to have accurate contents.
+ * (The IDL presents the database with references to rows that do not exist
+ * removed.)
*
- * The client must be careful not to retain pointers to data in 'column' across
- * calls to ovsdb_idl_run(), even when that function returns false, because
- * the client is not alerted to changes.
+ * This function is only useful if 'monitor_everything_by_default' was false in
+ * the call to ovsdb_idl_create(). This function should be called between
+ * ovsdb_idl_create() and the first call to ovsdb_idl_run().
+ */
+void
+ovsdb_idl_add_table(struct ovsdb_idl *idl,
+ const struct ovsdb_idl_table_class *tc)
+{
+ size_t i;
+
+ for (i = 0; i < idl->class->n_tables; i++) {
+ struct ovsdb_idl_table *table = &idl->tables[i];
+
+ if (table->class == tc) {
+ table->need_table = true;
+ return;
+ }
+ }
+
+ NOT_REACHED();
+}
+
+/* Turns off OVSDB_IDL_ALERT for 'column' in 'idl'.
*
- * This function should be called after ovsdb_idl_create(), but before the
- * first call to ovsdb_idl_run(). For any given column, this function may be
- * called or ovsdb_idl_omit() may be called, but not both. */
+ * This function should be called between ovsdb_idl_create() and the first call
+ * to ovsdb_idl_run().
+ */
void
-ovsdb_idl_set_write_only(struct ovsdb_idl *idl,
- const struct ovsdb_idl_column *column)
+ovsdb_idl_omit_alert(struct ovsdb_idl *idl,
+ const struct ovsdb_idl_column *column)
{
- ovsdb_idl_set_mode(idl, column, OVSDB_IDL_MODE_WO);
+ *ovsdb_idl_get_mode(idl, column) &= ~OVSDB_IDL_ALERT;
}
-/* By default, 'idl' replicates all of the columns in the remote database.
- * Call this function to omit replicating 'column'. This saves CPU time and
- * bandwidth to the database.
+/* Sets the mode for 'column' in 'idl' to 0. See the big comment above
+ * OVSDB_IDL_MONITOR for details.
*
- * This function should be called after ovsdb_idl_create(), but before the
- * first call to ovsdb_idl_run(). For any given column, this function may be
- * called or ovsdb_idl_set_write_only() may be called, but not both. */
+ * This function should be called between ovsdb_idl_create() and the first call
+ * to ovsdb_idl_run().
+ */
void
ovsdb_idl_omit(struct ovsdb_idl *idl, const struct ovsdb_idl_column *column)
{
- ovsdb_idl_set_mode(idl, column, OVSDB_IDL_MODE_NONE);
+ *ovsdb_idl_get_mode(idl, column) = 0;
}
\f
static void
struct json *monitor_request, *columns;
size_t j;
- monitor_request = json_object_create();
- columns = json_array_create_empty();
+ columns = table->need_table ? json_array_create_empty() : NULL;
for (j = 0; j < tc->n_columns; j++) {
const struct ovsdb_idl_column *column = &tc->columns[j];
- if (table->modes[j] != OVSDB_IDL_MODE_NONE) {
+ if (table->modes[j] & OVSDB_IDL_MONITOR) {
+ if (!columns) {
+ columns = json_array_create_empty();
+ }
json_array_add(columns, json_string_create(column->name));
}
}
- json_object_put(monitor_request, "columns", columns);
- json_object_put(monitor_requests, tc->name, monitor_request);
+
+ if (columns) {
+ monitor_request = json_object_create();
+ json_object_put(monitor_request, "columns", columns);
+ json_object_put(monitor_requests, tc->name, monitor_request);
+ }
}
json_destroy(idl->monitor_request_id);
if (!ovsdb_datum_equals(old, &datum, &column->type)) {
ovsdb_datum_swap(old, &datum);
- if (table->modes[column_idx] == OVSDB_IDL_MODE_RW) {
+ if (table->modes[column_idx] & OVSDB_IDL_ALERT) {
changed = true;
}
} else {
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;
+}
\f
/* Transactions. */
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:
return "success";
case TXN_TRY_AGAIN:
return "try again";
+ case TXN_NOT_LOCKED:
+ return "not locked";
case TXN_ERROR:
return "error";
}
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);
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();
}
}
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? */
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;
+ 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 {
struct json *row_json;
struct json *op;
} 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)));
&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);
}
"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;
}
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;
}
}
hmap_remove(&txn->idl->outstanding_txns, &txn->hmap_node);
}
+/* Writes 'datum' to the specified 'column' in 'row_'. Updates both 'row_'
+ * itself and the structs derived from it (e.g. the "struct ovsrec_*", for
+ * ovs-vswitchd).
+ *
+ * 'datum' must have the correct type for its column. The IDL does not check
+ * that it meets schema constraints, but ovsdb-server will do so at commit time
+ * so it had better be correct.
+ *
+ * A transaction must be in progress. Replication of 'column' must not have
+ * been disabled (by calling ovsdb_idl_omit()).
+ *
+ * Usually this function is used indirectly through one of the "set" functions
+ * 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,
assert(row->new != NULL);
assert(column_idx < class->n_columns);
- assert(row->table->modes[column_idx] != OVSDB_IDL_MODE_NONE);
+ 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,
(column->parse)(row, &row->new[column_idx]);
}
+/* Causes the original contents of 'column' in 'row_' to be verified as a
+ * 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.
+ *
+ * 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
+ * read as part of a read-modify-write operation.
+ *
+ * In some cases ovsdb_idl_txn_verify() reduces to a no-op, because the current
+ * value of 'column' is already known:
+ *
+ * - If 'row_' is a row created by the current transaction (returned by
+ * ovsdb_idl_txn_insert()).
+ *
+ * - If 'column' has already been modified (with ovsdb_idl_txn_write())
+ * within the current transaction.
+ *
+ * Because of the latter property, always call ovsdb_idl_txn_verify() *before*
+ * ovsdb_idl_txn_write() for a given read-modify-write.
+ *
+ * A transaction must be in progress.
+ *
+ * Usually this function is used indirectly through one of the "verify"
+ * functions generated by ovsdb-idlc. */
void
ovsdb_idl_txn_verify(const struct ovsdb_idl_row *row_,
const struct ovsdb_idl_column *column)
size_t 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;
bitmap_set1(row->prereqs, column_idx);
}
+/* Deletes 'row_' from its table. May free 'row_', so it must not be
+ * accessed afterward.
+ *
+ * A transaction must be in progress.
+ *
+ * Usually this function is used indirectly through one of the "delete"
+ * functions generated by ovsdb-idlc. */
void
ovsdb_idl_txn_delete(const struct ovsdb_idl_row *row_)
{
row->new = NULL;
}
+/* Inserts and returns a new row in the table with the specified 'class' in the
+ * database with open transaction 'txn'.
+ *
+ * The new row is assigned a provisional UUID. If 'uuid' is null then one is
+ * randomly generated; otherwise 'uuid' should specify a randomly generated
+ * UUID not otherwise in use. ovsdb-server will assign a different UUID when
+ * 'txn' is committed, but the IDL will replace any uses of the provisional
+ * UUID in the data to be to be committed by the UUID assigned by
+ * ovsdb-server.
+ *
+ * Usually this function is used indirectly through one of the "insert"
+ * functions generated by ovsdb-idlc. */
const struct ovsdb_idl_row *
ovsdb_idl_txn_insert(struct ovsdb_idl_txn *txn,
const struct ovsdb_idl_table_class *class,
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++) {
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);
}
}
- 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)) {
}
status = (hard_errors ? TXN_ERROR
+ : lock_errors ? TXN_NOT_LOCKED
: soft_errors ? TXN_TRY_AGAIN
: TXN_SUCCESS);
}
{
return txn->idl;
}
+\f
+/* 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;
+ }
+ }
+ }
+}
git://git.onelab.eu / sliver-openvswitch.git / blobdiff