X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fovsdb-idl.c;h=7556b7f390122ed6b6eab4611572be6025d2d1ad;hb=HEAD;hp=ba58895af6e1e2ddff3698addf5c8f4670b7e541;hpb=1e86ae6f51bcc91d2fa36e4154bc6e540251eaf8;p=sliver-openvswitch.git diff --git a/lib/ovsdb-idl.c b/lib/ovsdb-idl.c index ba58895af..7556b7f39 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, 2012, 2013 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -17,7 +17,6 @@ #include "ovsdb-idl.h" -#include #include #include #include @@ -25,6 +24,7 @@ #include "bitmap.h" #include "dynamic-string.h" +#include "fatal-signal.h" #include "json.h" #include "jsonrpc.h" #include "ovsdb-data.h" @@ -33,10 +33,10 @@ #include "poll-loop.h" #include "shash.h" #include "util.h" - -#define THIS_MODULE VLM_ovsdb_idl #include "vlog.h" +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 * (the destination). @@ -65,10 +65,17 @@ struct ovsdb_idl { 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; + bool verify_write_only; + + /* 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; @@ -86,14 +93,14 @@ struct ovsdb_idl_txn { struct ds comment; /* Increments. */ - char *inc_table; - char *inc_column; - struct json *inc_where; + const char *inc_table; + const char *inc_column; + struct uuid inc_row; unsigned int inc_index; 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 { @@ -111,13 +118,13 @@ static void ovsdb_idl_send_monitor_request(struct ovsdb_idl *); static void ovsdb_idl_parse_update(struct ovsdb_idl *, const struct json *); static struct ovsdb_error *ovsdb_idl_parse_update__(struct ovsdb_idl *, const struct json *); -static void ovsdb_idl_process_update(struct ovsdb_idl_table *, +static bool ovsdb_idl_process_update(struct ovsdb_idl_table *, const struct uuid *, const struct json *old, const struct json *new); static void ovsdb_idl_insert_row(struct ovsdb_idl_row *, const struct json *); static void ovsdb_idl_delete_row(struct ovsdb_idl_row *); -static void ovsdb_idl_modify_row(struct ovsdb_idl_row *, const struct json *); +static bool ovsdb_idl_modify_row(struct ovsdb_idl_row *, const struct json *); static bool ovsdb_idl_row_is_orphan(const struct ovsdb_idl_row *); static struct ovsdb_idl_row *ovsdb_idl_row_create__( @@ -135,15 +142,47 @@ 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 + * 'class'. (Ordinarily 'class' is compiled from an OVSDB schema automatically + * by ovsdb-idlc.) + * + * Passes 'retry' to jsonrpc_session_open(). See that function for + * documentation. + * + * 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, bool retry) { 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); + idl->session = jsonrpc_session_open(remote, retry); shash_init(&idl->table_by_name); idl->tables = xmalloc(class->n_tables * sizeof *idl->tables); for (i = 0; i < class->n_tables; i++) { @@ -151,15 +190,16 @@ ovsdb_idl_create(const char *remote, const struct ovsdb_idl_class *class) struct ovsdb_idl_table *table = &idl->tables[i]; size_t j; - assert(!shash_find(&idl->table_by_name, tc->name)); - shash_add(&idl->table_by_name, tc->name, table); + shash_add_assert(&idl->table_by_name, tc->name, table); table->class = tc; + table->modes = xmalloc(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]; - assert(!shash_find(&table->columns, column->name)); - shash_add(&table->columns, column->name, column); + shash_add_assert(&table->columns, column->name, column); } hmap_init(&table->rows); table->idl = idl; @@ -170,13 +210,14 @@ ovsdb_idl_create(const char *remote, const struct ovsdb_idl_class *class) return idl; } +/* Destroys 'idl' and all of the data structures that it manages. */ void ovsdb_idl_destroy(struct ovsdb_idl *idl) { if (idl) { size_t i; - assert(!idl->txn); + ovs_assert(!idl->txn); ovsdb_idl_clear(idl); jsonrpc_session_close(idl->session); @@ -184,10 +225,14 @@ ovsdb_idl_destroy(struct ovsdb_idl *idl) struct ovsdb_idl_table *table = &idl->tables[i]; shash_destroy(&table->columns); hmap_destroy(&table->rows); + free(table->modes); } 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); + hmap_destroy(&idl->outstanding_txns); free(idl); } } @@ -207,15 +252,13 @@ ovsdb_idl_clear(struct ovsdb_idl *idl) } changed = true; - HMAP_FOR_EACH_SAFE (row, next_row, struct ovsdb_idl_row, hmap_node, - &table->rows) { + HMAP_FOR_EACH_SAFE (row, next_row, hmap_node, &table->rows) { struct ovsdb_idl_arc *arc, *next_arc; if (!ovsdb_idl_row_is_orphan(row)) { ovsdb_idl_row_unparse(row); } - LIST_FOR_EACH_SAFE (arc, next_arc, struct ovsdb_idl_arc, src_node, - &row->src_arcs) { + LIST_FOR_EACH_SAFE (arc, next_arc, src_node, &row->src_arcs) { free(arc); } /* No need to do anything with dst_arcs: some node has those arcs @@ -230,15 +273,18 @@ ovsdb_idl_clear(struct ovsdb_idl *idl) } } +/* Processes a batch of messages from the database server on 'idl'. This may + * cause the IDL's contents to change. The client may check for that with + * ovsdb_idl_get_seqno(). */ void ovsdb_idl_run(struct ovsdb_idl *idl) { int i; - assert(!idl->txn); + ovs_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); @@ -246,6 +292,9 @@ 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; } @@ -254,24 +303,35 @@ 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 - && !strcmp(msg->id->u.string, "echo")) { - /* It's a reply to our echo request. Ignore it. */ + && 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_ERROR || msg->type == JSONRPC_REPLY) && ovsdb_idl_txn_process_reply(idl, msg)) { @@ -284,13 +344,12 @@ 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); } } +/* Arranges for poll_block() to wake up when ovsdb_idl_run() has something to + * do or when activity occurs on a transaction on 'idl'. */ void ovsdb_idl_wait(struct ovsdb_idl *idl) { @@ -298,23 +357,188 @@ ovsdb_idl_wait(struct ovsdb_idl *idl) jsonrpc_session_recv_wait(idl->session); } +/* Returns a "sequence number" that represents the state of 'idl'. When + * ovsdb_idl_run() changes the database, the sequence number changes. The + * initial fetch of the entire contents of the remote database is considered to + * be one kind of change. Successfully acquiring a lock, if one has been + * configured with ovsdb_idl_set_lock(), is also considered to be a change. + * + * As long as the sequence number does not change, the client may continue to + * use any data structures it obtains from 'idl'. But when it changes, the + * client must not access any of these data structures again, because they + * could have freed or reused for other purposes. + * + * The sequence number can occasionally change even if the database does not. + * This happens if the connection to the database drops and reconnects, which + * causes the database contents to be reloaded even if they didn't change. (It + * could also happen if the database server sends out a "change" that reflects + * what the IDL already thought was in the database. The database server is + * not supposed to do that, but bugs could in theory cause it to do so.) */ unsigned int ovsdb_idl_get_seqno(const struct ovsdb_idl *idl) { return idl->change_seqno; } +/* Returns true if 'idl' successfully connected to the remote database and + * retrieved its contents (even if the connection subsequently dropped and is + * in the process of reconnecting). If so, then 'idl' contains an atomic + * snapshot of the database's contents (but it might be arbitrarily old if the + * connection dropped). + * + * Returns false if 'idl' has never connected or retrieved the database's + * contents. If so, 'idl' is empty. */ bool ovsdb_idl_has_ever_connected(const struct ovsdb_idl *idl) { return ovsdb_idl_get_seqno(idl) != 0; } +/* Reconfigures 'idl' so that it would reconnect to the database, if + * connection was dropped. */ +void +ovsdb_idl_enable_reconnect(struct ovsdb_idl *idl) +{ + jsonrpc_session_enable_reconnect(idl->session); +} + +/* Forces 'idl' to drop its connection to the database and reconnect. In the + * meantime, the contents of 'idl' will not change. */ void ovsdb_idl_force_reconnect(struct ovsdb_idl *idl) { jsonrpc_session_force_reconnect(idl->session); } + +/* Some IDL users should only write to write-only columns. Furthermore, + * writing to a column which is not write-only can cause serious performance + * degradations for these users. This function causes 'idl' to reject writes + * to columns which are not marked write only using ovsdb_idl_omit_alert(). */ +void +ovsdb_idl_verify_write_only(struct ovsdb_idl *idl) +{ + idl->verify_write_only = true; +} + +bool +ovsdb_idl_is_alive(const struct ovsdb_idl *idl) +{ + return jsonrpc_session_is_alive(idl->session); +} + +int +ovsdb_idl_get_last_error(const struct ovsdb_idl *idl) +{ + return jsonrpc_session_get_last_error(idl->session); +} + +static unsigned char * +ovsdb_idl_get_mode(struct ovsdb_idl *idl, + const struct ovsdb_idl_column *column) +{ + size_t i; + + ovs_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]) { + return &table->modes[column - tc->columns]; + } + } + + OVS_NOT_REACHED(); +} + +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 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.) + * + * 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; + } + } + + OVS_NOT_REACHED(); +} + +/* Turns off OVSDB_IDL_ALERT for 'column' in 'idl'. + * + * This function should be called between ovsdb_idl_create() and the first call + * to ovsdb_idl_run(). + */ +void +ovsdb_idl_omit_alert(struct ovsdb_idl *idl, + const struct ovsdb_idl_column *column) +{ + *ovsdb_idl_get_mode(idl, column) &= ~OVSDB_IDL_ALERT; +} + +/* Sets the mode for 'column' in 'idl' to 0. See the big comment above + * OVSDB_IDL_MONITOR for details. + * + * 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_get_mode(idl, column) = 0; +} static void ovsdb_idl_send_monitor_request(struct ovsdb_idl *idl) @@ -328,16 +552,24 @@ ovsdb_idl_send_monitor_request(struct ovsdb_idl *idl) const struct ovsdb_idl_table *table = &idl->tables[i]; const struct ovsdb_idl_table_class *tc = table->class; struct json *monitor_request, *columns; - size_t i; + size_t j; - monitor_request = json_object_create(); - columns = json_array_create_empty(); - for (i = 0; i < tc->n_columns; i++) { - const struct ovsdb_idl_column *column = &tc->columns[i]; - json_array_add(columns, json_string_create(column->name)); + 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_MONITOR) { + if (!columns) { + columns = json_array_create_empty(); + } + json_array_add(columns, json_string_create(column->name)); + } + } + + if (columns) { + monitor_request = json_object_create(); + json_object_put(monitor_request, "columns", columns); + json_object_put(monitor_requests, tc->name, monitor_request); } - json_object_put(monitor_request, "columns", columns); - json_object_put(monitor_requests, tc->name, monitor_request); } json_destroy(idl->monitor_request_id); @@ -352,11 +584,7 @@ ovsdb_idl_send_monitor_request(struct ovsdb_idl *idl) static void ovsdb_idl_parse_update(struct ovsdb_idl *idl, const struct json *table_updates) { - struct ovsdb_error *error; - - idl->change_seqno++; - - error = ovsdb_idl_parse_update__(idl, table_updates); + struct ovsdb_error *error = ovsdb_idl_parse_update__(idl, table_updates); if (error) { if (!VLOG_DROP_WARN(&syntax_rl)) { char *s = ovsdb_error_to_string(error); @@ -436,7 +664,9 @@ ovsdb_idl_parse_update__(struct ovsdb_idl *idl, "and \"new\" members"); } - ovsdb_idl_process_update(table, &uuid, old_json, new_json); + if (ovsdb_idl_process_update(table, &uuid, old_json, new_json)) { + idl->change_seqno++; + } } } @@ -448,8 +678,7 @@ ovsdb_idl_get_row(struct ovsdb_idl_table *table, const struct uuid *uuid) { struct ovsdb_idl_row *row; - HMAP_FOR_EACH_WITH_HASH (row, struct ovsdb_idl_row, hmap_node, - uuid_hash(uuid), &table->rows) { + HMAP_FOR_EACH_WITH_HASH (row, hmap_node, uuid_hash(uuid), &table->rows) { if (uuid_equals(&row->uuid, uuid)) { return row; } @@ -457,7 +686,9 @@ ovsdb_idl_get_row(struct ovsdb_idl_table *table, const struct uuid *uuid) return NULL; } -static void +/* Returns true if a column with mode OVSDB_IDL_MODE_RW changed, false + * otherwise. */ +static bool ovsdb_idl_process_update(struct ovsdb_idl_table *table, const struct uuid *uuid, const struct json *old, const struct json *new) @@ -474,6 +705,7 @@ ovsdb_idl_process_update(struct ovsdb_idl_table *table, VLOG_WARN_RL(&semantic_rl, "cannot delete missing row "UUID_FMT" " "from table %s", UUID_ARGS(uuid), table->class->name); + return false; } } else if (!old) { /* Insert row. */ @@ -484,14 +716,14 @@ ovsdb_idl_process_update(struct ovsdb_idl_table *table, } else { VLOG_WARN_RL(&semantic_rl, "cannot add existing row "UUID_FMT" to " "table %s", UUID_ARGS(uuid), table->class->name); - ovsdb_idl_modify_row(row, new); + return ovsdb_idl_modify_row(row, new); } } else { /* Modify row. */ if (row) { /* XXX perhaps we should check the 'old' values? */ if (!ovsdb_idl_row_is_orphan(row)) { - ovsdb_idl_modify_row(row, new); + return ovsdb_idl_modify_row(row, new); } else { VLOG_WARN_RL(&semantic_rl, "cannot modify missing but " "referenced row "UUID_FMT" in table %s", @@ -504,13 +736,18 @@ ovsdb_idl_process_update(struct ovsdb_idl_table *table, ovsdb_idl_insert_row(ovsdb_idl_row_create(table, uuid), new); } } + + return true; } -static void +/* Returns true if a column with mode OVSDB_IDL_MODE_RW changed, false + * otherwise. */ +static bool ovsdb_idl_row_update(struct ovsdb_idl_row *row, const struct json *row_json) { struct ovsdb_idl_table *table = row->table; struct shash_node *node; + bool changed = false; SHASH_FOR_EACH (node, json_object(row_json)) { const char *column_name = node->name; @@ -527,8 +764,19 @@ ovsdb_idl_row_update(struct ovsdb_idl_row *row, const struct json *row_json) error = ovsdb_datum_from_json(&datum, &column->type, node->data, NULL); if (!error) { - ovsdb_datum_swap(&row->old[column - table->class->columns], - &datum); + unsigned int column_idx = column - table->class->columns; + struct ovsdb_datum *old = &row->old[column_idx]; + + if (!ovsdb_datum_equals(old, &datum, &column->type)) { + ovsdb_datum_swap(old, &datum); + if (table->modes[column_idx] & OVSDB_IDL_ALERT) { + changed = true; + } + } else { + /* Didn't really change but the OVSDB monitor protocol always + * includes every value in a row. */ + } + ovsdb_datum_destroy(&datum, &column->type); } else { char *s = ovsdb_error_to_string(error); @@ -539,6 +787,7 @@ ovsdb_idl_row_update(struct ovsdb_idl_row *row, const struct json *row_json) ovsdb_error_destroy(error); } } + return changed; } /* When a row A refers to row B through a column with a "refTable" constraint, @@ -605,7 +854,7 @@ ovsdb_idl_row_unparse(struct ovsdb_idl_row *row) static void ovsdb_idl_row_clear_old(struct ovsdb_idl_row *row) { - assert(row->old == row->new); + ovs_assert(row->old == row->new); if (!ovsdb_idl_row_is_orphan(row)) { const struct ovsdb_idl_table_class *class = row->table->class; size_t i; @@ -626,8 +875,10 @@ ovsdb_idl_row_clear_new(struct ovsdb_idl_row *row) const struct ovsdb_idl_table_class *class = row->table->class; size_t i; - BITMAP_FOR_EACH_1 (i, class->n_columns, row->written) { - ovsdb_datum_destroy(&row->new[i], &class->columns[i].type); + if (row->written) { + BITMAP_FOR_EACH_1 (i, class->n_columns, row->written) { + ovsdb_datum_destroy(&row->new[i], &class->columns[i].type); + } } free(row->new); free(row->written); @@ -644,8 +895,7 @@ ovsdb_idl_row_clear_arcs(struct ovsdb_idl_row *row, bool destroy_dsts) /* Delete all forward arcs. If 'destroy_dsts', destroy any orphaned rows * that this causes to be unreferenced. */ - LIST_FOR_EACH_SAFE (arc, next, struct ovsdb_idl_arc, src_node, - &row->src_arcs) { + LIST_FOR_EACH_SAFE (arc, next, src_node, &row->src_arcs) { list_remove(&arc->dst_node); if (destroy_dsts && ovsdb_idl_row_is_orphan(arc->dst) @@ -673,8 +923,7 @@ ovsdb_idl_row_reparse_backrefs(struct ovsdb_idl_row *row) * (If duplicate arcs were possible then we would need to make sure that * 'next' didn't also point into 'arc''s destination, but we forbid * duplicate arcs.) */ - LIST_FOR_EACH_SAFE (arc, next, struct ovsdb_idl_arc, dst_node, - &row->dst_arcs) { + LIST_FOR_EACH_SAFE (arc, next, dst_node, &row->dst_arcs) { struct ovsdb_idl_row *ref = arc->src; ovsdb_idl_row_unparse(ref); @@ -687,6 +936,7 @@ static struct ovsdb_idl_row * ovsdb_idl_row_create__(const struct ovsdb_idl_table_class *class) { struct ovsdb_idl_row *row = xzalloc(class->allocation_size); + class->row_init(row); list_init(&row->src_arcs); list_init(&row->dst_arcs); hmap_node_nullify(&row->txn_node); @@ -719,7 +969,7 @@ ovsdb_idl_insert_row(struct ovsdb_idl_row *row, const struct json *row_json) const struct ovsdb_idl_table_class *class = row->table->class; size_t i; - assert(!row->old && !row->new); + ovs_assert(!row->old && !row->new); row->old = row->new = xmalloc(class->n_columns * sizeof *row->old); for (i = 0; i < class->n_columns; i++) { ovsdb_datum_init_default(&row->old[i], &class->columns[i].type); @@ -743,13 +993,19 @@ ovsdb_idl_delete_row(struct ovsdb_idl_row *row) } } -static void +/* Returns true if a column with mode OVSDB_IDL_MODE_RW changed, false + * otherwise. */ +static bool ovsdb_idl_modify_row(struct ovsdb_idl_row *row, const struct json *row_json) { + bool changed; + ovsdb_idl_row_unparse(row); ovsdb_idl_row_clear_arcs(row, true); - ovsdb_idl_row_update(row, row_json); + changed = ovsdb_idl_row_update(row, row_json); ovsdb_idl_row_parse(row); + + return changed; } static bool @@ -782,6 +1038,7 @@ ovsdb_idl_table_from_class(const struct ovsdb_idl *idl, return &idl->tables[table_class - idl->class->tables]; } +/* Called by ovsdb-idlc generated code. */ struct ovsdb_idl_row * ovsdb_idl_get_row_arc(struct ovsdb_idl_row *src, struct ovsdb_idl_table_class *dst_table_class, @@ -826,6 +1083,8 @@ ovsdb_idl_get_row_arc(struct ovsdb_idl_row *src, } } +/* Searches 'tc''s table in 'idl' for a row with UUID 'uuid'. Returns a + * pointer to the row if there is one, otherwise a null pointer. */ const struct ovsdb_idl_row * ovsdb_idl_get_row_for_uuid(const struct ovsdb_idl *idl, const struct ovsdb_idl_table_class *tc, @@ -848,6 +1107,12 @@ next_real_row(struct ovsdb_idl_table *table, struct hmap_node *node) return NULL; } +/* Returns a row in 'table_class''s table in 'idl', or a null pointer if that + * table is empty. + * + * Database tables are internally maintained as hash tables, so adding or + * removing rows while traversing the same table can cause some rows to be + * visited twice or not at apply. */ const struct ovsdb_idl_row * ovsdb_idl_first_row(const struct ovsdb_idl *idl, const struct ovsdb_idl_table_class *table_class) @@ -857,6 +1122,8 @@ ovsdb_idl_first_row(const struct ovsdb_idl *idl, return next_real_row(table, hmap_first(&table->rows)); } +/* Returns a row following 'row' within its table, or a null pointer if 'row' + * is the last row in its table. */ const struct ovsdb_idl_row * ovsdb_idl_next_row(const struct ovsdb_idl_row *row) { @@ -864,16 +1131,86 @@ ovsdb_idl_next_row(const struct ovsdb_idl_row *row) return next_real_row(table, hmap_next(&table->rows, &row->hmap_node)); } + +/* Reads and returns the value of 'column' within 'row'. If an ongoing + * transaction has changed 'column''s value, the modified value is returned. + * + * The caller must not modify or free the returned value. + * + * Various kinds of changes can invalidate the returned value: writing to the + * same 'column' in 'row' (e.g. with ovsdb_idl_txn_write()), deleting 'row' + * (e.g. with ovsdb_idl_txn_delete()), or completing an ongoing transaction + * (e.g. with ovsdb_idl_txn_commit() or ovsdb_idl_txn_abort()). If the + * returned value is needed for a long time, it is best to make a copy of it + * with ovsdb_datum_clone(). */ +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; + size_t column_idx; + + ovs_assert(!ovsdb_idl_row_is_synthetic(row)); + + class = row->table->class; + column_idx = column - class->columns; + + ovs_assert(row->new != NULL); + ovs_assert(column_idx < class->n_columns); + + if (row->written && bitmap_is_set(row->written, column_idx)) { + return &row->new[column_idx]; + } else if (row->old) { + return &row->old[column_idx]; + } else { + return ovsdb_datum_default(&column->type); + } +} + +/* Same as ovsdb_idl_read(), except that it also asserts that 'column' has key + * type 'key_type' and value type 'value_type'. (Scalar and set types will + * have a value type of OVSDB_TYPE_VOID.) + * + * This is useful in code that "knows" that a particular column has a given + * type, so that it will abort if someone changes the column's type without + * updating the code that uses it. */ +const struct ovsdb_datum * +ovsdb_idl_get(const struct ovsdb_idl_row *row, + const struct ovsdb_idl_column *column, + enum ovsdb_atomic_type key_type OVS_UNUSED, + enum ovsdb_atomic_type value_type OVS_UNUSED) +{ + ovs_assert(column->type.key.type == key_type); + ovs_assert(column->type.value.type == value_type); + + 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. */ static void ovsdb_idl_txn_complete(struct ovsdb_idl_txn *txn, enum ovsdb_idl_txn_status); +/* Returns a string representation of 'status'. The caller must not modify or + * free the returned string. + * + * The return value is probably useful only for debug log messages and unit + * tests. */ 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: @@ -884,61 +1221,102 @@ ovsdb_idl_txn_status_to_string(enum ovsdb_idl_txn_status status) return "success"; case TXN_TRY_AGAIN: return "try again"; + case TXN_NOT_LOCKED: + return "not locked"; case TXN_ERROR: return "error"; } return ""; } +/* Starts a new transaction on 'idl'. A given ovsdb_idl may only have a single + * active transaction at a time. See the large comment in ovsdb-idl.h for + * general information on transactions. */ struct ovsdb_idl_txn * ovsdb_idl_txn_create(struct ovsdb_idl *idl) { struct ovsdb_idl_txn *txn; - assert(!idl->txn); + ovs_assert(!idl->txn); idl->txn = txn = xmalloc(sizeof *txn); 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->inc_table = NULL; txn->inc_column = NULL; - txn->inc_where = NULL; hmap_init(&txn->inserted_rows); return txn; } +/* Appends 's', which is treated as a printf()-type format string, to the + * comments that will be passed to the OVSDB server when 'txn' is committed. + * (The comment will be committed to the OVSDB log, which "ovsdb-tool + * show-log" can print in a relatively human-readable form.) */ void -ovsdb_idl_txn_add_comment(struct ovsdb_idl_txn *txn, const char *s) +ovsdb_idl_txn_add_comment(struct ovsdb_idl_txn *txn, const char *s, ...) { + va_list args; + if (txn->comment.length) { ds_put_char(&txn->comment, '\n'); } - ds_put_cstr(&txn->comment, s); + + va_start(args, s); + ds_put_format_valist(&txn->comment, s, args); + va_end(args); } +/* Marks 'txn' as a transaction that will not actually modify the database. In + * almost every way, the transaction is treated like other transactions. It + * must be committed or aborted like other transactions, it will be sent to the + * database server like other transactions, and so on. The only difference is + * that the operations sent to the database server will include, as the last + * step, an "abort" operation, so that any changes made by the transaction will + * not actually take effect. */ void ovsdb_idl_txn_set_dry_run(struct ovsdb_idl_txn *txn) { txn->dry_run = true; } +/* Causes 'txn', when committed, to increment the value of 'column' within + * 'row' by 1. 'column' must have an integer type. After 'txn' commits + * successfully, the client may retrieve the final (incremented) value of + * 'column' with ovsdb_idl_txn_get_increment_new_value(). + * + * The client could accomplish something similar with ovsdb_idl_read(), + * ovsdb_idl_txn_verify() and ovsdb_idl_txn_write(), or with ovsdb-idlc + * generated wrappers for these functions. However, ovsdb_idl_txn_increment() + * will never (by itself) fail because of a verify error. + * + * The intended use is for incrementing the "next_cfg" column in the + * Open_vSwitch table. */ void -ovsdb_idl_txn_increment(struct ovsdb_idl_txn *txn, const char *table, - const char *column, const struct json *where) +ovsdb_idl_txn_increment(struct ovsdb_idl_txn *txn, + const struct ovsdb_idl_row *row, + const struct ovsdb_idl_column *column) { - assert(!txn->inc_table); - txn->inc_table = xstrdup(table); - txn->inc_column = xstrdup(column); - txn->inc_where = where ? json_clone(where) : json_array_create_empty(); + ovs_assert(!txn->inc_table); + ovs_assert(column->type.key.type == OVSDB_TYPE_INTEGER); + ovs_assert(column->type.value.type == OVSDB_TYPE_VOID); + + txn->inc_table = row->table->class->name; + txn->inc_column = column->name; + txn->inc_row = row->uuid; } +/* Destroys 'txn' and frees all associated memory. If ovsdb_idl_txn_commit() + * has been called for 'txn' but the commit is still incomplete (that is, the + * last call returned TXN_INCOMPLETE) then the transaction may or may not still + * end up committing at the database server, but the client will not be able to + * get any further status information back. */ void ovsdb_idl_txn_destroy(struct ovsdb_idl_txn *txn) { @@ -951,21 +1329,18 @@ ovsdb_idl_txn_destroy(struct ovsdb_idl_txn *txn) ovsdb_idl_txn_abort(txn); ds_destroy(&txn->comment); free(txn->error); - free(txn->inc_table); - free(txn->inc_column); - json_destroy(txn->inc_where); - HMAP_FOR_EACH_SAFE (insert, next, struct ovsdb_idl_txn_insert, hmap_node, - &txn->inserted_rows) { + HMAP_FOR_EACH_SAFE (insert, next, hmap_node, &txn->inserted_rows) { free(insert); } hmap_destroy(&txn->inserted_rows); free(txn); } +/* Causes poll_block() to wake up if 'txn' has completed committing. */ 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(); } } @@ -1005,8 +1380,7 @@ ovsdb_idl_txn_get_row(const struct ovsdb_idl_txn *txn, const struct uuid *uuid) { const struct ovsdb_idl_row *row; - HMAP_FOR_EACH_WITH_HASH (row, struct ovsdb_idl_row, txn_node, - uuid_hash(uuid), &txn->txn_rows) { + HMAP_FOR_EACH_WITH_HASH (row, txn_node, uuid_hash(uuid), &txn->txn_rows) { if (uuid_equals(&row->uuid, uuid)) { return row; } @@ -1064,8 +1438,7 @@ ovsdb_idl_txn_disassemble(struct ovsdb_idl_txn *txn) * transaction and fail to update the graph. */ txn->idl->txn = NULL; - HMAP_FOR_EACH_SAFE (row, next, struct ovsdb_idl_row, txn_node, - &txn->txn_rows) { + HMAP_FOR_EACH_SAFE (row, next, txn_node, &txn->txn_rows) { if (row->old) { if (row->written) { ovsdb_idl_row_unparse(row); @@ -1094,6 +1467,55 @@ ovsdb_idl_txn_disassemble(struct ovsdb_idl_txn *txn) hmap_init(&txn->txn_rows); } +/* Attempts to commit 'txn'. Returns the status of the commit operation, one + * of the following TXN_* constants: + * + * TXN_INCOMPLETE: + * + * The transaction is in progress, but not yet complete. The caller + * should call again later, after calling ovsdb_idl_run() to let the IDL + * do OVSDB protocol processing. + * + * TXN_UNCHANGED: + * + * The transaction is complete. (It didn't actually change the database, + * so the IDL didn't send any request to the database server.) + * + * TXN_ABORTED: + * + * The caller previously called ovsdb_idl_txn_abort(). + * + * TXN_SUCCESS: + * + * The transaction was successful. The update made by the transaction + * (and possibly other changes made by other database clients) should + * already be visible in the IDL. + * + * TXN_TRY_AGAIN: + * + * The transaction failed for some transient reason, e.g. because a + * "verify" operation reported an inconsistency or due to a network + * problem. The caller should wait for a change to the database, then + * compose a new transaction, and commit the new transaction. + * + * Use the return value of ovsdb_idl_get_seqno() to wait for a change in + * the database. It is important to use its return value *before* the + * initial call to ovsdb_idl_txn_commit() as the baseline for this + * purpose, because the change that one should wait for can happen after + * the initial call but before the call that returns TXN_TRY_AGAIN, and + * using some other baseline value in that situation could cause an + * indefinite wait if the database rarely changes. + * + * TXN_NOT_LOCKED: + * + * The transaction failed because the IDL has been configured to require + * a database lock (with ovsdb_idl_set_lock()) but didn't get it yet or + * has already lost it. + * + * Committing a transaction rolls back all of the changes that it made to the + * IDL's copy of the database. If the transaction commits successfully, then + * the database server will send an update and, thus, the IDL will be updated + * with the committed changes. */ enum ovsdb_idl_txn_status ovsdb_idl_txn_commit(struct ovsdb_idl_txn *txn) { @@ -1105,11 +1527,26 @@ 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, struct ovsdb_idl_row, txn_node, &txn->txn_rows) { + HMAP_FOR_EACH (row, txn_node, &txn->txn_rows) { /* XXX check that deleted rows exist even if no prereqs? */ if (row->prereqs) { const struct ovsdb_idl_table_class *class = row->table->class; @@ -1141,19 +1578,21 @@ ovsdb_idl_txn_commit(struct ovsdb_idl_txn *txn) /* Add updates. */ any_updates = false; - HMAP_FOR_EACH (row, struct ovsdb_idl_row, txn_node, &txn->txn_rows) { + 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; @@ -1166,6 +1605,8 @@ 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))); @@ -1180,24 +1621,35 @@ ovsdb_idl_txn_commit(struct ovsdb_idl_txn *txn) row_json = json_object_create(); json_object_put(op, "row", row_json); - BITMAP_FOR_EACH_1 (idx, class->n_columns, row->written) { - const struct ovsdb_idl_column *column = &class->columns[idx]; - - if (row->old - ? !ovsdb_datum_equals(&row->old[idx], &row->new[idx], - &column->type) - : !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 (row->written) { + BITMAP_FOR_EACH_1 (idx, class->n_columns, row->written) { + const struct ovsdb_idl_column *column = + &class->columns[idx]; + + if (row->old + || !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); } @@ -1214,7 +1666,8 @@ ovsdb_idl_txn_commit(struct ovsdb_idl_txn *txn) json_object_put_string(op, "op", "mutate"); json_object_put_string(op, "table", txn->inc_table); json_object_put(op, "where", - substitute_uuids(json_clone(txn->inc_where), txn)); + substitute_uuids(where_uuid_equals(&txn->inc_row), + txn)); json_object_put(op, "mutations", json_array_create_1( json_array_create_3( @@ -1227,7 +1680,8 @@ ovsdb_idl_txn_commit(struct ovsdb_idl_txn *txn) json_object_put_string(op, "op", "select"); json_object_put_string(op, "table", txn->inc_table); json_object_put(op, "where", - substitute_uuids(json_clone(txn->inc_where), txn)); + substitute_uuids(where_uuid_equals(&txn->inc_row), + txn)); json_object_put(op, "columns", json_array_create_1(json_string_create( txn->inc_column))); @@ -1256,6 +1710,7 @@ 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; } @@ -1266,12 +1721,16 @@ ovsdb_idl_txn_commit(struct ovsdb_idl_txn *txn) /* Attempts to commit 'txn', blocking until the commit either succeeds or * fails. Returns the final commit status, which may be any TXN_* value other - * than TXN_INCOMPLETE. */ + * than TXN_INCOMPLETE. + * + * This function calls ovsdb_idl_run() on 'txn''s IDL, so it may cause the + * return value of ovsdb_idl_get_seqno() to change. */ enum ovsdb_idl_txn_status ovsdb_idl_txn_commit_block(struct ovsdb_idl_txn *txn) { enum ovsdb_idl_txn_status status; + fatal_signal_run(); while ((status = ovsdb_idl_txn_commit(txn)) == TXN_INCOMPLETE) { ovsdb_idl_run(txn->idl); ovsdb_idl_wait(txn->idl); @@ -1281,22 +1740,39 @@ ovsdb_idl_txn_commit_block(struct ovsdb_idl_txn *txn) return status; } +/* Returns the final (incremented) value of the column in 'txn' that was set to + * be incremented by ovsdb_idl_txn_increment(). 'txn' must have committed + * successfully. */ int64_t ovsdb_idl_txn_get_increment_new_value(const struct ovsdb_idl_txn *txn) { - assert(txn->status == TXN_SUCCESS); + ovs_assert(txn->status == TXN_SUCCESS); return txn->inc_new_value; } +/* Aborts 'txn' without sending it to the database server. This is effective + * only if ovsdb_idl_txn_commit() has not yet been called for 'txn'. + * Otherwise, it has no effect. + * + * Aborting a transaction doesn't free its memory. Use + * ovsdb_idl_txn_destroy() to do that. */ 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; } } +/* Returns a string that reports the error status for 'txn'. The caller must + * not modify or free the returned string. A call to ovsdb_idl_txn_destroy() + * for 'txn' may free the returned string. + * + * The return value is ordinarily one of the strings that + * ovsdb_idl_txn_status_to_string() would return, but if the transaction failed + * due to an error reported by the database server, the return value is that + * error. */ const char * ovsdb_idl_txn_get_error(const struct ovsdb_idl_txn *txn) { @@ -1333,8 +1809,8 @@ ovsdb_idl_txn_get_insert_uuid(const struct ovsdb_idl_txn *txn, { const struct ovsdb_idl_txn_insert *insert; - assert(txn->status == TXN_SUCCESS || txn->status == TXN_UNCHANGED); - HMAP_FOR_EACH_IN_BUCKET (insert, struct ovsdb_idl_txn_insert, hmap_node, + ovs_assert(txn->status == TXN_SUCCESS || txn->status == TXN_UNCHANGED); + HMAP_FOR_EACH_IN_BUCKET (insert, hmap_node, uuid_hash(uuid), &txn->inserted_rows) { if (uuid_equals(uuid, &insert->dummy)) { return &insert->real; @@ -1351,35 +1827,68 @@ ovsdb_idl_txn_complete(struct ovsdb_idl_txn *txn, hmap_remove(&txn->idl->outstanding_txns, &txn->hmap_node); } -void -ovsdb_idl_txn_read(const struct ovsdb_idl_row *row, - const struct ovsdb_idl_column *column, - struct ovsdb_datum *datum) +/* 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.) */ +static void +ovsdb_idl_txn_write__(const struct ovsdb_idl_row *row_, + const struct ovsdb_idl_column *column, + struct ovsdb_datum *datum, bool owns_datum) { - const struct ovsdb_idl_table_class *class = row->table->class; - size_t column_idx = column - class->columns; + struct ovsdb_idl_row *row = CONST_CAST(struct ovsdb_idl_row *, row_); + const struct ovsdb_idl_table_class *class; + size_t column_idx; + bool write_only; - assert(row->new != NULL); - if (row->written && bitmap_is_set(row->written, column_idx)) { - ovsdb_datum_clone(datum, &row->new[column_idx], &column->type); - } else if (row->old) { - ovsdb_datum_clone(datum, &row->old[column_idx], &column->type); - } else { - ovsdb_datum_init_default(datum, &column->type); + if (ovsdb_idl_row_is_synthetic(row)) { + goto discard_datum; } -} -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; + class = row->table->class; + column_idx = column - class->columns; + write_only = row->table->modes[column_idx] == OVSDB_IDL_MONITOR; + + ovs_assert(row->new != NULL); + ovs_assert(column_idx < class->n_columns); + ovs_assert(row->old == NULL || + row->table->modes[column_idx] & OVSDB_IDL_MONITOR); + + if (row->table->idl->verify_write_only && !write_only) { + VLOG_ERR("Bug: Attempt to write to a read/write column (%s:%s) when" + " explicitly configured not to.", class->name, column->name); + goto discard_datum; + } + + /* 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 (write_only && ovsdb_datum_equals(ovsdb_idl_read(row, column), + datum, &column->type)) { + goto discard_datum; + } - assert(row->new != NULL); - assert(column_idx < class->n_columns); if (hmap_node_is_null(&row->txn_node)) { hmap_insert(&row->table->idl->txn->txn_rows, &row->txn_node, uuid_hash(&row->uuid)); @@ -1395,20 +1904,84 @@ ovsdb_idl_txn_write(const struct ovsdb_idl_row *row_, } else { bitmap_set1(row->written, column_idx); } - row->new[column_idx] = *datum; + if (owns_datum) { + row->new[column_idx] = *datum; + } else { + ovsdb_datum_clone(&row->new[column_idx], datum, &column->type); + } (column->unparse)(row); (column->parse)(row, &row->new[column_idx]); + return; + +discard_datum: + if (owns_datum) { + ovsdb_datum_destroy(datum, &column->type); + } +} + +void +ovsdb_idl_txn_write(const struct ovsdb_idl_row *row, + const struct ovsdb_idl_column *column, + struct ovsdb_datum *datum) +{ + ovsdb_idl_txn_write__(row, column, datum, true); } +void +ovsdb_idl_txn_write_clone(const struct ovsdb_idl_row *row, + const struct ovsdb_idl_column *column, + const struct ovsdb_datum *datum) +{ + ovsdb_idl_txn_write__(row, column, + CONST_CAST(struct ovsdb_datum *, datum), false); +} + +/* 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_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 + * 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) { - 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; + struct ovsdb_idl_row *row = CONST_CAST(struct ovsdb_idl_row *, row_); + 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); + ovs_assert(row->new != NULL); + ovs_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; @@ -1424,16 +1997,27 @@ ovsdb_idl_txn_verify(const struct ovsdb_idl_row *row_, 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_) { - struct ovsdb_idl_row *row = (struct ovsdb_idl_row *) row_; + struct ovsdb_idl_row *row = CONST_CAST(struct ovsdb_idl_row *, row_); - assert(row->new != NULL); + if (ovsdb_idl_row_is_synthetic(row)) { + return; + } + + ovs_assert(row->new != NULL); if (!row->old) { ovsdb_idl_row_unparse(row); ovsdb_idl_row_clear_new(row); - assert(!row->prereqs); + ovs_assert(!row->prereqs); hmap_remove(&row->table->rows, &row->hmap_node); hmap_remove(&row->table->idl->txn->txn_rows, &row->txn_node); free(row); @@ -1447,15 +2031,34 @@ 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) + const struct ovsdb_idl_table_class *class, + const struct uuid *uuid) { struct ovsdb_idl_row *row = ovsdb_idl_row_create__(class); - uuid_generate(&row->uuid); + + if (uuid) { + ovs_assert(!ovsdb_idl_txn_get_row(txn, uuid)); + row->uuid = *uuid; + } else { + uuid_generate(&row->uuid); + } + row->table = ovsdb_idl_table_from_class(txn->idl, class); row->new = xmalloc(class->n_columns * sizeof *row->new); - row->written = bitmap_allocate(class->n_columns); hmap_insert(&row->table->rows, &row->hmap_node, uuid_hash(&row->uuid)); hmap_insert(&txn->txn_rows, &row->txn_node, uuid_hash(&row->uuid)); return row; @@ -1466,8 +2069,7 @@ ovsdb_idl_txn_abort_all(struct ovsdb_idl *idl) { struct ovsdb_idl_txn *txn; - HMAP_FOR_EACH (txn, struct ovsdb_idl_txn, hmap_node, - &idl->outstanding_txns) { + HMAP_FOR_EACH (txn, hmap_node, &idl->outstanding_txns) { ovsdb_idl_txn_complete(txn, TXN_TRY_AGAIN); } } @@ -1477,7 +2079,7 @@ ovsdb_idl_txn_find(struct ovsdb_idl *idl, const struct json *id) { struct ovsdb_idl_txn *txn; - HMAP_FOR_EACH_WITH_HASH (txn, struct ovsdb_idl_txn, hmap_node, + HMAP_FOR_EACH_WITH_HASH (txn, hmap_node, json_hash(id, 0), &idl->outstanding_txns) { if (json_equal(id, txn->request_id)) { return txn; @@ -1511,7 +2113,7 @@ ovsdb_idl_txn_process_inc_reply(struct ovsdb_idl_txn *txn, if (txn->inc_index + 2 > results->n) { VLOG_WARN_RL(&syntax_rl, "reply does not contain enough operations " - "for increment (has %u, needs %u)", + "for increment (has %"PRIuSIZE", needs %u)", results->n, txn->inc_index + 2); return false; } @@ -1525,7 +2127,7 @@ ovsdb_idl_txn_process_inc_reply(struct ovsdb_idl_txn *txn, } if (count->u.integer != 1) { VLOG_WARN_RL(&syntax_rl, - "\"mutate\" reply \"count\" is %"PRId64" instead of 1", + "\"mutate\" reply \"count\" is %lld instead of 1", count->u.integer); return false; } @@ -1536,7 +2138,7 @@ ovsdb_idl_txn_process_inc_reply(struct ovsdb_idl_txn *txn, return false; } if (rows->u.array.n != 1) { - VLOG_WARN_RL(&syntax_rl, "\"select\" reply \"rows\" has %u elements " + VLOG_WARN_RL(&syntax_rl, "\"select\" reply \"rows\" has %"PRIuSIZE" elements " "instead of 1", rows->u.array.n); return false; @@ -1566,7 +2168,7 @@ ovsdb_idl_txn_process_insert_reply(struct ovsdb_idl_txn_insert *insert, if (insert->op_index >= results->n) { VLOG_WARN_RL(&syntax_rl, "reply does not contain enough operations " - "for insert (has %u, needs %u)", + "for insert (has %"PRIuSIZE", needs %u)", results->n, insert->op_index); return false; } @@ -1585,6 +2187,7 @@ ovsdb_idl_txn_process_insert_reply(struct ovsdb_idl_txn_insert *insert, VLOG_WARN_RL(&syntax_rl, "\"insert\" reply \"uuid\" is not a JSON " "UUID: %s", s); free(s); + ovsdb_error_destroy(error); return false; } @@ -1614,6 +2217,7 @@ 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++) { @@ -1631,6 +2235,8 @@ 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); @@ -1650,15 +2256,14 @@ 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)) { hard_errors++; } - HMAP_FOR_EACH (insert, struct ovsdb_idl_txn_insert, hmap_node, - &txn->inserted_rows) { + HMAP_FOR_EACH (insert, hmap_node, &txn->inserted_rows) { if (!ovsdb_idl_txn_process_insert_reply(insert, ops)) { hard_errors++; } @@ -1666,6 +2271,7 @@ ovsdb_idl_txn_process_reply(struct ovsdb_idl *idl, } status = (hard_errors ? TXN_ERROR + : lock_errors ? TXN_NOT_LOCKED : soft_errors ? TXN_TRY_AGAIN : TXN_SUCCESS); } @@ -1674,17 +2280,155 @@ ovsdb_idl_txn_process_reply(struct ovsdb_idl *idl, return true; } +/* Returns the transaction currently active for 'row''s IDL. A transaction + * must currently be active. */ struct ovsdb_idl_txn * ovsdb_idl_txn_get(const struct ovsdb_idl_row *row) { struct ovsdb_idl_txn *txn = row->table->idl->txn; - assert(txn != NULL); + ovs_assert(txn != NULL); return txn; } +/* Returns the IDL on which 'txn' acts. */ struct ovsdb_idl * 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) +{ + ovs_assert(!idl->txn); + ovs_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; + } + } + } +}