diff options
Diffstat (limited to 'ctdb/server/ctdb_lock.c')
| -rw-r--r-- | ctdb/server/ctdb_lock.c | 1034 |
1 files changed, 1034 insertions, 0 deletions
diff --git a/ctdb/server/ctdb_lock.c b/ctdb/server/ctdb_lock.c new file mode 100644 index 0000000000..fc437b0fa7 --- /dev/null +++ b/ctdb/server/ctdb_lock.c @@ -0,0 +1,1034 @@ +/* + ctdb lock handling + provide API to do non-blocking locks for single or all databases + + Copyright (C) Amitay Isaacs 2012 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, see <http://www.gnu.org/licenses/>. +*/ +#include "includes.h" +#include "include/ctdb_private.h" +#include "include/ctdb_protocol.h" +#include "tevent.h" +#include "tdb.h" +#include "db_wrap.h" +#include "system/filesys.h" +#include "lib/util/dlinklist.h" + +/* + * Non-blocking Locking API + * + * 1. Create a child process to do blocking locks. + * 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 + * + * ctdb_lock_record() - get a lock on a record + * ctdb_lock_db() - get a lock on a DB + * ctdb_lock_alldb_prio() - get a lock on all DBs with given priority + * ctdb_lock_alldb() - get a lock on all DBs + * + * 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_ALLDB_PRIO, + LOCK_ALLDB, +}; + +static const char * const lock_type_str[] = { + "lock_record", + "lock_db", + "lock_alldb_prio", + "lock_db", +}; + +struct lock_request; + +/* lock_context is the common part for a lock request */ +struct lock_context { + struct lock_context *next, *prev; + enum lock_type type; + struct ctdb_context *ctdb; + struct ctdb_db_context *ctdb_db; + TDB_DATA key; + uint32_t priority; + bool auto_mark; + struct lock_request *req_queue; + 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; +}; + +/* 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; +}; + + +/* + * Support samba 3.6.x (and older) versions which do not set db priority. + * + * By default, all databases are set to priority 1. So only when priority + * is set to 1, check for databases that need higher priority. + */ +static bool later_db(struct ctdb_context *ctdb, const char *name) +{ + if (ctdb->tunable.samba3_hack == 0) { + return false; + } + + if (strstr(name, "brlock") || + strstr(name, "g_lock") || + strstr(name, "notify_onelevel") || + strstr(name, "serverid") || + strstr(name, "xattr_tdb")) { + return true; + } + + return false; +} + +typedef int (*db_handler_t)(struct ctdb_db_context *ctdb_db, + uint32_t priority, + void *private_data); + +static int ctdb_db_iterator(struct ctdb_context *ctdb, uint32_t priority, + db_handler_t handler, void *private_data) +{ + struct ctdb_db_context *ctdb_db; + int ret; + + for (ctdb_db = ctdb->db_list; ctdb_db; ctdb_db = ctdb_db->next) { + if (ctdb_db->priority != priority) { + continue; + } + if (later_db(ctdb, ctdb_db->db_name)) { + continue; + } + ret = handler(ctdb_db, priority, private_data); + if (ret != 0) { + return -1; + } + } + + /* If priority != 1, later_db check is not required and can return */ + if (priority != 1) { + return 0; + } + + for (ctdb_db = ctdb->db_list; ctdb_db; ctdb_db = ctdb_db->next) { + if (!later_db(ctdb, ctdb_db->db_name)) { + continue; + } + ret = handler(ctdb_db, priority, private_data); + if (ret != 0) { + return -1; + } + } + + return 0; +} + + +/* + * lock all databases - mark only + */ +static int db_lock_mark_handler(struct ctdb_db_context *ctdb_db, uint32_t priority, + void *private_data) +{ + int tdb_transaction_write_lock_mark(struct tdb_context *); + + DEBUG(DEBUG_INFO, ("marking locked database %s, priority:%u\n", + ctdb_db->db_name, priority)); + + if (tdb_transaction_write_lock_mark(ctdb_db->ltdb->tdb) != 0) { + DEBUG(DEBUG_ERR, ("Failed to mark (transaction lock) database %s\n", + ctdb_db->db_name)); + return -1; + } + + if (tdb_lockall_mark(ctdb_db->ltdb->tdb) != 0) { + DEBUG(DEBUG_ERR, ("Failed to mark (all lock) database %s\n", + ctdb_db->db_name)); + return -1; + } + + return 0; +} + +int ctdb_lockall_mark_prio(struct ctdb_context *ctdb, uint32_t priority) +{ + /* + * This function is only used by the main dameon 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. + */ + + if (ctdb->freeze_mode[priority] != CTDB_FREEZE_FROZEN) { + DEBUG(DEBUG_ERR, ("Attempt to mark all databases locked when not frozen\n")); + return -1; + } + + return ctdb_db_iterator(ctdb, priority, db_lock_mark_handler, NULL); +} + +static int ctdb_lockall_mark(struct ctdb_context *ctdb) +{ + uint32_t priority; + + for (priority=1; priority<=NUM_DB_PRIORITIES; priority++) { + if (ctdb_db_iterator(ctdb, priority, db_lock_mark_handler, NULL) != 0) { + return -1; + } + } + + return 0; +} + + +/* + * lock all databases - unmark only + */ +static int db_lock_unmark_handler(struct ctdb_db_context *ctdb_db, uint32_t priority, + void *private_data) +{ + int tdb_transaction_write_lock_unmark(struct tdb_context *); + + DEBUG(DEBUG_INFO, ("unmarking locked database %s, priority:%u\n", + ctdb_db->db_name, priority)); + + if (tdb_transaction_write_lock_unmark(ctdb_db->ltdb->tdb) != 0) { + DEBUG(DEBUG_ERR, ("Failed to unmark (transaction lock) database %s\n", + ctdb_db->db_name)); + return -1; + } + + if (tdb_lockall_unmark(ctdb_db->ltdb->tdb) != 0) { + DEBUG(DEBUG_ERR, ("Failed to unmark (all lock) database %s\n", + ctdb_db->db_name)); + return -1; + } + + return 0; +} + +int ctdb_lockall_unmark_prio(struct ctdb_context *ctdb, uint32_t priority) +{ + /* + * This function is only used by the main dameon 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. + */ + + if (ctdb->freeze_mode[priority] != CTDB_FREEZE_FROZEN) { + DEBUG(DEBUG_ERR, ("Attempt to unmark all databases locked when not frozen\n")); + return -1; + } + + return ctdb_db_iterator(ctdb, priority, db_lock_unmark_handler, NULL); +} + +static int ctdb_lockall_unmark(struct ctdb_context *ctdb) +{ + uint32_t priority; + + for (priority=NUM_DB_PRIORITIES; priority>=0; priority--) { + if (ctdb_db_iterator(ctdb, priority, db_lock_unmark_handler, NULL) != 0) { + return -1; + } + } + + return 0; +} + + +static void ctdb_lock_schedule(struct ctdb_context *ctdb); + +/* + * Destructor to kill the child locking process + */ +static int ctdb_lock_context_destructor(struct lock_context *lock_ctx) +{ + 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--; + CTDB_DECREMENT_STAT(lock_ctx->ctdb, locks.num_current); + if (lock_ctx->type == LOCK_RECORD || lock_ctx->type == LOCK_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) { + CTDB_DECREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_pending); + } + } + + ctdb_lock_schedule(lock_ctx->ctdb); + + return 0; +} + + +/* + * Destructor to remove lock request + */ +static int ctdb_lock_request_destructor(struct lock_request *lock_request) +{ + DLIST_REMOVE(lock_request->lctx->req_queue, lock_request); + return 0; +} + + +void ctdb_lock_free_request_context(struct lock_request *lock_req) +{ + struct lock_context *lock_ctx; + + lock_ctx = lock_req->lctx; + talloc_free(lock_req); + talloc_free(lock_ctx); +} + + +/* + * Process all the callbacks waiting for lock + * + * If lock has failed, callback is executed with locked=false + */ +static void process_callbacks(struct lock_context *lock_ctx, bool locked) +{ + struct lock_request *request, *next; + + if (lock_ctx->auto_mark && locked) { + switch (lock_ctx->type) { + case LOCK_RECORD: + tdb_chainlock_mark(lock_ctx->ctdb_db->ltdb->tdb, lock_ctx->key); + break; + + case LOCK_DB: + tdb_lockall_mark(lock_ctx->ctdb_db->ltdb->tdb); + break; + + case LOCK_ALLDB_PRIO: + ctdb_lockall_mark_prio(lock_ctx->ctdb, lock_ctx->priority); + break; + + case LOCK_ALLDB: + ctdb_lockall_mark(lock_ctx->ctdb); + break; + } + } + + /* 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; + } + + if (lock_ctx->auto_mark && locked) { + switch (lock_ctx->type) { + case LOCK_RECORD: + tdb_chainlock_unmark(lock_ctx->ctdb_db->ltdb->tdb, lock_ctx->key); + break; + + case LOCK_DB: + tdb_lockall_unmark(lock_ctx->ctdb_db->ltdb->tdb); + break; + + case LOCK_ALLDB_PRIO: + ctdb_lockall_unmark_prio(lock_ctx->ctdb, lock_ctx->priority); + break; + + case LOCK_ALLDB: + ctdb_lockall_unmark(lock_ctx->ctdb); + break; + } + } +} + + +static int lock_bucket_id(double t) +{ + double ms = 1.e-3, s = 1; + int id; + + if (t < 1*ms) { + id = 0; + } else if (t < 10*ms) { + id = 1; + } else if (t < 100*ms) { + id = 2; + } else if (t < 1*s) { + id = 3; + } else if (t < 2*s) { + id = 4; + } else if (t < 4*s) { + id = 5; + } else if (t < 8*s) { + id = 6; + } else if (t < 16*s) { + id = 7; + } else if (t < 32*s) { + id = 8; + } else if (t < 64*s) { + id = 9; + } else { + id = 10; + } + + return id; +} + +/* + * Callback routine when the required locks are obtained. + * Called from parent context + */ +static void ctdb_lock_handler(struct tevent_context *ev, + struct tevent_fd *tfd, + uint16_t flags, + void *private_data) +{ + struct lock_context *lock_ctx; + TALLOC_CTX *tmp_ctx = NULL; + char c; + bool locked; + double t; + int id; + + lock_ctx = talloc_get_type_abort(private_data, struct lock_context); + + /* cancel the timeout event */ + if (lock_ctx->ttimer) { + TALLOC_FREE(lock_ctx->ttimer); + } + + t = timeval_elapsed(&lock_ctx->start_time); + id = lock_bucket_id(t); + + if (lock_ctx->auto_mark) { + tmp_ctx = talloc_new(ev); + talloc_steal(tmp_ctx, lock_ctx); + } + + /* Read the status from the child process */ + read(lock_ctx->fd[0], &c, 1); + 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]); + } + } else { + CTDB_INCREMENT_STAT(lock_ctx->ctdb, locks.num_failed); + if (lock_ctx->ctdb_db) { + CTDB_INCREMENT_DB_STAT(lock_ctx->ctdb_db, locks.num_failed); + } + } + + process_callbacks(lock_ctx, locked); + + if (lock_ctx->auto_mark) { + talloc_free(tmp_ctx); + } +} + + +/* + * Callback routine when required locks are not obtained within timeout + * Called from parent context + */ +static void ctdb_lock_timeout_handler(struct tevent_context *ev, + struct tevent_timer *ttimer, + struct timeval current_time, + void *private_data) +{ + 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) { + DEBUG(DEBUG_WARNING, + ("Unable to get %s lock on database %s for %.0lf seconds\n", + (lock_ctx->type == LOCK_RECORD ? "RECORD" : "DB"), + lock_ctx->ctdb_db->db_name, + timeval_elapsed(&lock_ctx->start_time))); + } else { + DEBUG(DEBUG_WARNING, + ("Unable to get ALLDB locks for %.0lf seconds\n", + timeval_elapsed(&lock_ctx->start_time))); + } + + /* 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 = fork(); + if (pid == 0) { + execl(debug_locks, debug_locks, NULL); + } + } else { + DEBUG(DEBUG_WARNING, + (__location__ + " Unable to setup lock debugging - no memory?\n")); + } + + /* reset the timeout timer */ + // talloc_free(lock_ctx->ttimer); + lock_ctx->ttimer = tevent_add_timer(ctdb->ev, + lock_ctx, + timeval_current_ofs(10, 0), + ctdb_lock_timeout_handler, + (void *)lock_ctx); +} + + +static int db_count_handler(struct ctdb_db_context *ctdb_db, uint32_t priority, + void *private_data) +{ + int *count = (int *)private_data; + + (*count)++; + + return 0; +} + +struct db_namelist { + char **names; + int n; +}; + +static int db_name_handler(struct ctdb_db_context *ctdb_db, uint32_t priority, + void *private_data) +{ + struct db_namelist *list = (struct db_namelist *)private_data; + + list->names[list->n] = talloc_strdup(list->names, ctdb_db->db_path); + list->n++; + + return 0; +} + +static char **lock_helper_args(TALLOC_CTX *mem_ctx, struct lock_context *lock_ctx, int fd) +{ + struct ctdb_context *ctdb = lock_ctx->ctdb; + char **args = NULL; + int nargs, i; + int priority; + struct db_namelist list; + + switch (lock_ctx->type) { + case LOCK_RECORD: + nargs = 6; + break; + + case LOCK_DB: + nargs = 5; + break; + + case LOCK_ALLDB_PRIO: + nargs = 4; + ctdb_db_iterator(ctdb, lock_ctx->priority, db_count_handler, &nargs); + break; + + case LOCK_ALLDB: + nargs = 4; + for (priority=1; priority<NUM_DB_PRIORITIES; priority++) { + ctdb_db_iterator(ctdb, priority, db_count_handler, &nargs); + } + break; + } + + /* Add extra argument for null termination */ + nargs++; + + args = talloc_array(mem_ctx, char *, nargs); + if (args == NULL) { + return NULL; + } + + args[0] = talloc_strdup(args, "ctdb_lock_helper"); + args[1] = talloc_asprintf(args, "%d", getpid()); + args[2] = talloc_asprintf(args, "%d", fd); + + switch (lock_ctx->type) { + case LOCK_RECORD: + args[3] = talloc_strdup(args, "RECORD"); + args[4] = talloc_strdup(args, lock_ctx->ctdb_db->db_path); + if (lock_ctx->key.dsize == 0) { + args[5] = talloc_strdup(args, "NULL"); + } else { + args[5] = hex_encode_talloc(args, lock_ctx->key.dptr, lock_ctx->key.dsize); + } + break; + + case LOCK_DB: + args[3] = talloc_strdup(args, "DB"); + args[4] = talloc_strdup(args, lock_ctx->ctdb_db->db_path); + break; + + case LOCK_ALLDB_PRIO: + args[3] = talloc_strdup(args, "DB"); + list.names = args; + list.n = 4; + ctdb_db_iterator(ctdb, lock_ctx->priority, db_name_handler, &list); + break; + + case LOCK_ALLDB: + args[3] = talloc_strdup(args, "DB"); + list.names = args; + list.n = 4; + for (priority=1; priority<NUM_DB_PRIORITIES; priority++) { + ctdb_db_iterator(ctdb, priority, db_name_handler, &list); + } + break; + } + + /* Make sure last argument is NULL */ + args[nargs-1] = NULL; + + for (i=0; i<nargs-1; i++) { + if (args[i] == NULL) { + talloc_free(args); + return NULL; + } + } + + return args; +} + + +/* + * 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 + */ +static void ctdb_lock_schedule(struct ctdb_context *ctdb) +{ + struct lock_context *lock_ctx, *next_ctx, *active_ctx; + int ret; + TALLOC_CTX *tmp_ctx; + const char *helper = BINDIR "/ctdb_lock_helper"; + static const char *prog = NULL; + char **args; + + if (prog == NULL) { + const char *t; + + t = getenv("CTDB_LOCK_HELPER"); + if (t != NULL) { + prog = talloc_strdup(ctdb, t); + } else { + prog = talloc_strdup(ctdb, helper); + } + 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) { + next_ctx = lock_ctx->next; + if (! lock_ctx->req_queue) { + DEBUG(DEBUG_INFO, ("Removing lock context without lock requests\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); + } else { + active_ctx = find_lock_context(ctdb->lock_current, lock_ctx->ctdb_db, + lock_ctx->key, lock_ctx->priority, + lock_ctx->type); + if (active_ctx == NULL) { + /* Found a lock context with lock requests */ + break; + } + + /* There is already a child waiting for the + * same key. So don't schedule another child + * just yet. + */ + } + lock_ctx = next_ctx; + } + + if (lock_ctx == NULL) { + return; + } + + lock_ctx->child = -1; + ret = pipe(lock_ctx->fd); + if (ret != 0) { + DEBUG(DEBUG_ERR, ("Failed to create pipe in ctdb_lock_schedule\n")); + return; + } + + set_close_on_exec(lock_ctx->fd[0]); + + /* Create data for child process */ + tmp_ctx = talloc_new(lock_ctx); + if (tmp_ctx == NULL) { + DEBUG(DEBUG_ERR, ("Failed to allocate memory for helper args\n")); + close(lock_ctx->fd[0]); + close(lock_ctx->fd[1]); + return; + } + + /* Create arguments for lock helper */ + args = lock_helper_args(tmp_ctx, lock_ctx, lock_ctx->fd[1]); + if (args == NULL) { + DEBUG(DEBUG_ERR, ("Failed to create lock helper args\n")); + close(lock_ctx->fd[0]); + close(lock_ctx->fd[1]); + talloc_free(tmp_ctx); + return; + } + + lock_ctx->child = ctdb_fork(ctdb); + + if (lock_ctx->child == (pid_t)-1) { + DEBUG(DEBUG_ERR, ("Failed to create a child in ctdb_lock_schedule\n")); + close(lock_ctx->fd[0]); + close(lock_ctx->fd[1]); + talloc_free(tmp_ctx); + return; + } + + + /* Child process */ + if (lock_ctx->child == 0) { + ret = execv(prog, args); + if (ret < 0) { + DEBUG(DEBUG_ERR, ("Failed to execute helper %s (%d, %s)\n", + prog, errno, strerror(errno))); + } + _exit(1); + } + + /* Parent process */ + close(lock_ctx->fd[1]); + + talloc_set_destructor(lock_ctx, ctdb_lock_context_destructor); + + talloc_free(tmp_ctx); + + /* Set up timeout handler */ + lock_ctx->ttimer = tevent_add_timer(ctdb->ev, + lock_ctx, + timeval_current_ofs(10, 0), + ctdb_lock_timeout_handler, + (void *)lock_ctx); + if (lock_ctx->ttimer == NULL) { + ctdb_kill(ctdb, lock_ctx->child, SIGKILL); + lock_ctx->child = -1; + talloc_set_destructor(lock_ctx, NULL); + close(lock_ctx->fd[0]); + return; + } + + /* Set up callback */ + lock_ctx->tfd = tevent_add_fd(ctdb->ev, + lock_ctx, + lock_ctx->fd[0], + EVENT_FD_READ, + ctdb_lock_handler, + (void *)lock_ctx); + if (lock_ctx->tfd == NULL) { + TALLOC_FREE(lock_ctx->ttimer); + ctdb_kill(ctdb, lock_ctx->child, SIGKILL); + lock_ctx->child = -1; + talloc_set_destructor(lock_ctx, NULL); + close(lock_ctx->fd[0]); + return; + } + tevent_fd_set_auto_close(lock_ctx->tfd); + + /* 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++; +} + + +/* + * Lock record / db depending on type + */ +static struct lock_request *ctdb_lock_internal(struct ctdb_context *ctdb, + struct ctdb_db_context *ctdb_db, + TDB_DATA key, + uint32_t priority, + void (*callback)(void *, bool), + void *private_data, + enum lock_type type, + bool auto_mark) +{ + struct lock_context *lock_ctx; + struct lock_request *request; + + if (callback == NULL) { + DEBUG(DEBUG_WARNING, ("No callback function specified, not locking\n")); + 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 */ + 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; + } + + 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; + } + lock_ctx->priority = priority; + lock_ctx->auto_mark = auto_mark; + + lock_ctx->child = -1; + lock_ctx->block_child = -1; + + 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(); + } + + if ((request = talloc_zero(lock_ctx, struct lock_request)) == NULL) { + return NULL; + } + + 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); + + return request; +} + + +/* + * obtain a lock on a record in a database + */ +struct lock_request *ctdb_lock_record(struct ctdb_db_context *ctdb_db, + TDB_DATA key, + bool auto_mark, + void (*callback)(void *, bool), + void *private_data) +{ + return ctdb_lock_internal(ctdb_db->ctdb, + ctdb_db, + key, + 0, + callback, + private_data, + LOCK_RECORD, + auto_mark); +} + + +/* + * obtain a lock on a database + */ +struct lock_request *ctdb_lock_db(struct ctdb_db_context *ctdb_db, + bool auto_mark, + void (*callback)(void *, bool), + void *private_data) +{ + return ctdb_lock_internal(ctdb_db->ctdb, + ctdb_db, + tdb_null, + 0, + callback, + private_data, + LOCK_DB, + auto_mark); +} + + +/* + * obtain locks on all databases of specified priority + */ +struct lock_request *ctdb_lock_alldb_prio(struct ctdb_context *ctdb, + uint32_t priority, + bool auto_mark, + void (*callback)(void *, bool), + void *private_data) +{ + if (priority < 0 || priority > NUM_DB_PRIORITIES) { + DEBUG(DEBUG_ERR, ("Invalid db priority: %u\n", priority)); + return NULL; + } + + return ctdb_lock_internal(ctdb, + NULL, + tdb_null, + priority, + callback, + private_data, + LOCK_ALLDB_PRIO, + auto_mark); +} + + +/* + * obtain locks on all databases + */ +struct lock_request *ctdb_lock_alldb(struct ctdb_context *ctdb, + bool auto_mark, + void (*callback)(void *, bool), + void *private_data) +{ + return ctdb_lock_internal(ctdb, + NULL, + tdb_null, + 0, + callback, + private_data, + LOCK_ALLDB, + auto_mark); +} + |