* 2. Once the locks are obtained, signal parent process via fd.
* 3. Invoke registered callback routine with locking status.
* 4. If the child process cannot get locks within certain time,
- * diagnose using /proc/locks and log warning message
+ * execute an external script to debug.
*
* ctdb_lock_record() - get a lock on a record
* ctdb_lock_db() - get a lock on a DB
* auto_mark - whether to mark/unmark DBs in before/after callback
*/
-/* FIXME: Add a tunable max_lock_processes_per_db */
-#define MAX_LOCK_PROCESSES_PER_DB (100)
-
enum lock_type {
LOCK_RECORD,
LOCK_DB,
"lock_record",
"lock_db",
"lock_alldb_prio",
- "lock_db",
+ "lock_alldb",
};
struct lock_request;
TDB_DATA key;
uint32_t priority;
bool auto_mark;
- struct lock_request *req_queue;
+ struct lock_request *request;
pid_t child;
int fd[2];
struct tevent_fd *tfd;
struct tevent_timer *ttimer;
- pid_t block_child;
- int block_fd[2];
struct timeval start_time;
+ uint32_t key_hash;
+ bool can_schedule;
};
/* lock_request is the client specific part for a lock request */
struct lock_request {
- struct lock_request *next, *prev;
struct lock_context *lctx;
void (*callback)(void *, bool);
void *private_data;
int ctdb_lockall_unmark_prio(struct ctdb_context *ctdb, uint32_t priority)
{
/*
- * This function is only used by the main dameon during recovery.
+ * This function is only used by the main daemon during recovery.
* At this stage, the databases have already been locked, by a
* dedicated child process. The freeze_mode variable is used to track
* whether the actual locks are held by the child process or not.
{
uint32_t priority;
- for (priority=NUM_DB_PRIORITIES; priority>=0; priority--) {
+ for (priority=NUM_DB_PRIORITIES; priority>0; priority--) {
if (ctdb_db_iterator(ctdb, priority, db_lock_unmark_handler, NULL) != 0) {
return -1;
}
if (lock_ctx->child > 0) {
ctdb_kill(lock_ctx->ctdb, lock_ctx->child, SIGKILL);
DLIST_REMOVE(lock_ctx->ctdb->lock_current, lock_ctx);
- lock_ctx->ctdb->lock_num_current--;
+ if (lock_ctx->ctdb_db) {
+ lock_ctx->ctdb_db->lock_num_current--;
+ }
CTDB_DECREMENT_STAT(lock_ctx->ctdb, locks.num_current);
- if (lock_ctx->type == LOCK_RECORD || lock_ctx->type == LOCK_DB) {
+ if (lock_ctx->ctdb_db) {
CTDB_DECREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_current);
}
} else {
DLIST_REMOVE(lock_ctx->ctdb->lock_pending, lock_ctx);
- lock_ctx->ctdb->lock_num_pending--;
CTDB_DECREMENT_STAT(lock_ctx->ctdb, locks.num_pending);
- if (lock_ctx->type == LOCK_RECORD || lock_ctx->type == LOCK_DB) {
+ if (lock_ctx->ctdb_db) {
CTDB_DECREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_pending);
}
}
*/
static int ctdb_lock_request_destructor(struct lock_request *lock_request)
{
- DLIST_REMOVE(lock_request->lctx->req_queue, lock_request);
+ lock_request->lctx->request = NULL;
return 0;
}
-
void ctdb_lock_free_request_context(struct lock_request *lock_req)
{
struct lock_context *lock_ctx;
*/
static void process_callbacks(struct lock_context *lock_ctx, bool locked)
{
- struct lock_request *request, *next;
+ struct lock_request *request;
if (lock_ctx->auto_mark && locked) {
switch (lock_ctx->type) {
}
}
- /* Iterate through all callbacks */
- request = lock_ctx->req_queue;
- while (request) {
- if (lock_ctx->auto_mark) {
- /* Reset the destructor, so request is not removed from the list */
- talloc_set_destructor(request, NULL);
- }
-
- /* In case, callback frees the request, store next */
- next = request->next;
- request->callback(request->private_data, locked);
- request = next;
+ request = lock_ctx->request;
+ if (lock_ctx->auto_mark) {
+ /* Reset the destructor, so request is not removed from the list */
+ talloc_set_destructor(request, NULL);
}
+ request->callback(request->private_data, locked);
if (lock_ctx->auto_mark && locked) {
switch (lock_ctx->type) {
}
/* Read the status from the child process */
- read(lock_ctx->fd[0], &c, 1);
- locked = (c == 0 ? true : false);
+ if (read(lock_ctx->fd[0], &c, 1) != 1) {
+ locked = false;
+ } else {
+ locked = (c == 0 ? true : false);
+ }
/* Update statistics */
- CTDB_DECREMENT_STAT(lock_ctx->ctdb, locks.num_pending);
CTDB_INCREMENT_STAT(lock_ctx->ctdb, locks.num_calls);
if (lock_ctx->ctdb_db) {
- CTDB_DECREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_pending);
CTDB_INCREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_calls);
}
if (locked) {
if (lock_ctx->ctdb_db) {
- CTDB_INCREMENT_STAT(lock_ctx->ctdb, locks.num_current);
CTDB_INCREMENT_STAT(lock_ctx->ctdb, locks.buckets[id]);
CTDB_UPDATE_LATENCY(lock_ctx->ctdb, lock_ctx->ctdb_db,
lock_type_str[lock_ctx->type], locks.latency,
lock_ctx->start_time);
- CTDB_INCREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_current);
CTDB_UPDATE_DB_LATENCY(lock_ctx->ctdb_db, lock_type_str[lock_ctx->type], locks.latency, t);
CTDB_INCREMENT_DB_STAT(lock_ctx->ctdb_db, locks.buckets[id]);
}
struct timeval current_time,
void *private_data)
{
- const char *cmd = getenv("CTDB_DEBUG_LOCKS");
+ static const char * debug_locks = NULL;
struct lock_context *lock_ctx;
struct ctdb_context *ctdb;
pid_t pid;
lock_ctx = talloc_get_type_abort(private_data, struct lock_context);
ctdb = lock_ctx->ctdb;
- if (lock_ctx->type == LOCK_RECORD || lock_ctx->type == LOCK_DB) {
+ if (lock_ctx->ctdb_db) {
DEBUG(DEBUG_WARNING,
("Unable to get %s lock on database %s for %.0lf seconds\n",
(lock_ctx->type == LOCK_RECORD ? "RECORD" : "DB"),
timeval_elapsed(&lock_ctx->start_time)));
}
- /* fire a child process to find the blocking process */
- if (cmd != NULL) {
- pid = fork();
+ /* Fire a child process to find the blocking process. */
+ if (debug_locks == NULL) {
+ debug_locks = getenv("CTDB_DEBUG_LOCKS");
+ if (debug_locks == NULL) {
+ debug_locks = talloc_asprintf(ctdb,
+ "%s/debug_locks.sh",
+ getenv("CTDB_BASE"));
+ }
+ }
+ if (debug_locks != NULL) {
+ pid = vfork();
if (pid == 0) {
- execl(cmd, cmd, NULL);
+ execl(debug_locks, debug_locks, NULL);
+ _exit(0);
}
+ ctdb_track_child(ctdb, pid);
+ } else {
+ DEBUG(DEBUG_WARNING,
+ (__location__
+ " Unable to setup lock debugging - no memory?\n"));
}
/* reset the timeout timer */
}
-/*
- * Find the lock context of a given type
- */
-static struct lock_context *find_lock_context(struct lock_context *lock_list,
- struct ctdb_db_context *ctdb_db,
- TDB_DATA key,
- uint32_t priority,
- enum lock_type type)
-{
- struct lock_context *lock_ctx;
-
- /* Search active locks */
- for (lock_ctx=lock_list; lock_ctx; lock_ctx=lock_ctx->next) {
- if (lock_ctx->type != type) {
- continue;
- }
-
- switch (lock_ctx->type) {
- case LOCK_RECORD:
- if (ctdb_db == lock_ctx->ctdb_db &&
- key.dsize == lock_ctx->key.dsize &&
- memcmp(key.dptr, lock_ctx->key.dptr, key.dsize) == 0) {
- goto done;
- }
- break;
-
- case LOCK_DB:
- if (ctdb_db == lock_ctx->ctdb_db) {
- goto done;
- }
- break;
-
- case LOCK_ALLDB_PRIO:
- if (priority == lock_ctx->priority) {
- goto done;
- }
- break;
-
- case LOCK_ALLDB:
- goto done;
- break;
- }
- }
-
- /* Did not find the lock context we are searching for */
- lock_ctx = NULL;
-
-done:
- return lock_ctx;
-
-}
-
-
/*
* Schedule a new lock child process
* Set up callback handler and timeout handler
CTDB_NO_MEMORY_VOID(ctdb, prog);
}
- if (ctdb->lock_num_current >= MAX_LOCK_PROCESSES_PER_DB) {
- return;
- }
-
if (ctdb->lock_pending == NULL) {
return;
}
/* Find a lock context with requests */
lock_ctx = ctdb->lock_pending;
while (lock_ctx != NULL) {
- if (! lock_ctx->req_queue) {
- next_ctx = lock_ctx->next;
- DEBUG(DEBUG_INFO, ("Removing lock context without lock requests\n"));
+ next_ctx = lock_ctx->next;
+ if (! lock_ctx->request) {
+ DEBUG(DEBUG_INFO, ("Removing lock context without lock request\n"));
DLIST_REMOVE(ctdb->lock_pending, lock_ctx);
- ctdb->lock_num_pending--;
CTDB_DECREMENT_STAT(ctdb, locks.num_pending);
if (lock_ctx->ctdb_db) {
CTDB_DECREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_pending);
}
talloc_free(lock_ctx);
- lock_ctx = next_ctx;
- continue;
} else {
- /* Found a lock context with lock requests */
- break;
+ if (lock_ctx->ctdb_db == NULL ||
+ lock_ctx->ctdb_db->lock_num_current < ctdb->tunable.lock_processes_per_db) {
+ /* Found a lock context with lock requests */
+ break;
+ }
}
+ lock_ctx = next_ctx;
}
if (lock_ctx == NULL) {
return;
}
- lock_ctx->child = ctdb_fork(ctdb);
+ lock_ctx->child = vfork();
if (lock_ctx->child == (pid_t)-1) {
DEBUG(DEBUG_ERR, ("Failed to create a child in ctdb_lock_schedule\n"));
}
/* Parent process */
+ ctdb_track_child(ctdb, lock_ctx->child);
close(lock_ctx->fd[1]);
talloc_set_destructor(lock_ctx, ctdb_lock_context_destructor);
/* Move the context from pending to current */
DLIST_REMOVE(ctdb->lock_pending, lock_ctx);
- ctdb->lock_num_pending--;
DLIST_ADD_END(ctdb->lock_current, lock_ctx, NULL);
- ctdb->lock_num_current++;
+ CTDB_DECREMENT_STAT(lock_ctx->ctdb, locks.num_pending);
+ CTDB_INCREMENT_STAT(lock_ctx->ctdb, locks.num_current);
+ if (lock_ctx->ctdb_db) {
+ lock_ctx->ctdb_db->lock_num_current++;
+ CTDB_DECREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_pending);
+ CTDB_INCREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_current);
+ }
}
enum lock_type type,
bool auto_mark)
{
- struct lock_context *lock_ctx;
+ struct lock_context *lock_ctx = NULL;
struct lock_request *request;
if (callback == NULL) {
return NULL;
}
- /* get a context for this key - search only the pending contexts,
- * current contexts might in the middle of processing callbacks */
- lock_ctx = find_lock_context(ctdb->lock_pending, ctdb_db, key, priority, type);
-
- /* No existing context, create one */
+ lock_ctx = talloc_zero(ctdb, struct lock_context);
if (lock_ctx == NULL) {
- lock_ctx = talloc_zero(ctdb, struct lock_context);
- if (lock_ctx == NULL) {
- DEBUG(DEBUG_ERR, ("Failed to create a new lock context\n"));
- return NULL;
- }
+ DEBUG(DEBUG_ERR, ("Failed to create a new lock context\n"));
+ return NULL;
+ }
- lock_ctx->type = type;
- lock_ctx->ctdb = ctdb;
- lock_ctx->ctdb_db = ctdb_db;
- lock_ctx->key.dsize = key.dsize;
- if (key.dsize > 0) {
- lock_ctx->key.dptr = talloc_memdup(lock_ctx, key.dptr, key.dsize);
- } else {
- lock_ctx->key.dptr = NULL;
+ if ((request = talloc_zero(lock_ctx, struct lock_request)) == NULL) {
+ talloc_free(lock_ctx);
+ return NULL;
+ }
+
+ lock_ctx->type = type;
+ lock_ctx->ctdb = ctdb;
+ lock_ctx->ctdb_db = ctdb_db;
+ lock_ctx->key.dsize = key.dsize;
+ if (key.dsize > 0) {
+ lock_ctx->key.dptr = talloc_memdup(lock_ctx, key.dptr, key.dsize);
+ if (lock_ctx->key.dptr == NULL) {
+ DEBUG(DEBUG_ERR, (__location__ "Memory allocation error\n"));
+ talloc_free(lock_ctx);
+ return NULL;
}
- lock_ctx->priority = priority;
- lock_ctx->auto_mark = auto_mark;
+ lock_ctx->key_hash = ctdb_hash(&key);
+ } else {
+ lock_ctx->key.dptr = NULL;
+ }
+ lock_ctx->priority = priority;
+ lock_ctx->auto_mark = auto_mark;
- lock_ctx->child = -1;
- lock_ctx->block_child = -1;
+ lock_ctx->request = request;
+ lock_ctx->child = -1;
+ /* Non-record locks are required by recovery and should be scheduled
+ * immediately, so keep them at the head of the pending queue.
+ */
+ if (lock_ctx->type == LOCK_RECORD) {
DLIST_ADD_END(ctdb->lock_pending, lock_ctx, NULL);
- ctdb->lock_num_pending++;
- CTDB_INCREMENT_STAT(ctdb, locks.num_pending);
- if (ctdb_db) {
- CTDB_INCREMENT_DB_STAT(ctdb_db, locks.num_pending);
- }
-
- /* Start the timer when we activate the context */
- lock_ctx->start_time = timeval_current();
+ } else {
+ DLIST_ADD(ctdb->lock_pending, lock_ctx);
}
-
- if ((request = talloc_zero(lock_ctx, struct lock_request)) == NULL) {
- return NULL;
+ CTDB_INCREMENT_STAT(ctdb, locks.num_pending);
+ if (ctdb_db) {
+ CTDB_INCREMENT_DB_STAT(ctdb_db, locks.num_pending);
}
+ /* Start the timer when we activate the context */
+ lock_ctx->start_time = timeval_current();
+
request->lctx = lock_ctx;
request->callback = callback;
request->private_data = private_data;
talloc_set_destructor(request, ctdb_lock_request_destructor);
- DLIST_ADD_END(lock_ctx->req_queue, request, NULL);
ctdb_lock_schedule(ctdb);
void (*callback)(void *, bool),
void *private_data)
{
- if (priority < 0 || priority > NUM_DB_PRIORITIES) {
+ if (priority < 1 || priority > NUM_DB_PRIORITIES) {
DEBUG(DEBUG_ERR, ("Invalid db priority: %u\n", priority));
return NULL;
}
git.samba.org / obnox / samba / samba-obnox.git / blobdiff