#include "includes.h"
#include "g_lock.h"
+#include "librpc/gen_ndr/messaging.h"
+#include "ctdbd_conn.h"
+#include "../lib/util/select.h"
static NTSTATUS g_lock_force_unlock(struct g_lock_ctx *ctx, const char *name,
struct server_id pid);
result->msg = msg;
result->db = db_open(result, lock_path("g_lock.tdb"), 0,
- TDB_CLEAR_IF_FIRST, O_RDWR|O_CREAT, 0700);
+ TDB_CLEAR_IF_FIRST|TDB_INCOMPATIBLE_HASH, O_RDWR|O_CREAT, 0700);
if (result->db == NULL) {
DEBUG(1, ("g_lock_init: Could not open g_lock.tdb"));
TALLOC_FREE(result);
(locks[i].lock_type & G_LOCK_PENDING) ?
"(pending)" : "(owner)"));
+ if (((locks[i].lock_type & G_LOCK_PENDING) == 0)
+ && !process_exists(locks[i].pid)) {
+
+ DEBUGADD(10, ("lock owner %s died -- discarding\n",
+ procid_str(talloc_tos(),
+ &locks[i].pid)));
+
+ if (i < (num_locks-1)) {
+ locks[i] = locks[num_locks-1];
+ }
+ num_locks -= 1;
+ }
+ }
+
+ *plocks = locks;
+ *pnum_locks = num_locks;
+ return true;
+}
+
+static void g_lock_cleanup(int *pnum_locks, struct g_lock_rec *locks)
+{
+ int i, num_locks;
+
+ num_locks = *pnum_locks;
+
+ DEBUG(10, ("g_lock_cleanup: %d locks\n", num_locks));
+
+ for (i=0; i<num_locks; i++) {
if (process_exists(locks[i].pid)) {
continue;
}
}
num_locks -= 1;
}
-
- *plocks = locks;
*pnum_locks = num_locks;
- return true;
+ return;
}
static struct g_lock_rec *g_lock_addrec(TALLOC_CTX *mem_ctx,
struct g_lock_rec *locks,
- int num_locks,
+ int *pnum_locks,
const struct server_id pid,
enum g_lock_type lock_type)
{
struct g_lock_rec *result;
+ int num_locks = *pnum_locks;
result = talloc_realloc(mem_ctx, locks, struct g_lock_rec,
num_locks+1);
result[num_locks].pid = pid;
result[num_locks].lock_type = lock_type;
+ *pnum_locks += 1;
return result;
}
uint32_t msg_type,
struct server_id server_id,
DATA_BLOB *data);
-static void g_lock_timedout(struct tevent_context *ev,
- struct tevent_timer *te,
- struct timeval current_time,
- void *private_data);
static NTSTATUS g_lock_trylock(struct g_lock_ctx *ctx, const char *name,
enum g_lock_type lock_type)
goto done;
}
- self = procid_self();
+ self = messaging_server_id(ctx->msg);
our_index = -1;
for (i=0; i<num_locks; i++) {
if (our_index == -1) {
/* First round, add ourself */
- locks = g_lock_addrec(talloc_tos(), locks, num_locks,
+ locks = g_lock_addrec(talloc_tos(), locks, &num_locks,
self, lock_type);
if (locks == NULL) {
DEBUG(10, ("g_lock_addrec failed\n"));
locks[our_index].lock_type = lock_type;
}
- data = make_tdb_data((uint8_t *)locks, talloc_get_size(locks));
+ if (NT_STATUS_IS_OK(status) && ((lock_type & G_LOCK_PENDING) == 0)) {
+ /*
+ * Walk through the list of locks, search for dead entries
+ */
+ g_lock_cleanup(&num_locks, locks);
+ }
+
+ data = make_tdb_data((uint8_t *)locks, num_locks * sizeof(*locks));
store_status = rec->store(rec, data, 0);
if (!NT_STATUS_IS_OK(store_status)) {
DEBUG(1, ("rec->store failed: %s\n",
struct tevent_timer *te = NULL;
NTSTATUS status;
bool retry = false;
- bool timedout = false;
+ struct timeval timeout_end;
+ struct timeval time_now;
DEBUG(10, ("Trying to acquire lock %d for %s\n", (int)lock_type,
name));
nt_errstr(status)));
return status;
}
-again:
- retry = false;
- status = g_lock_trylock(ctx, name, lock_type);
- if (NT_STATUS_IS_OK(status)) {
- DEBUG(10, ("Got lock %s\n", name));
- goto done;
- }
- if (!NT_STATUS_EQUAL(status, STATUS_PENDING)) {
- DEBUG(10, ("g_lock_trylock failed: %s\n",
- nt_errstr(status)));
- goto done;
- }
+ time_now = timeval_current();
+ timeout_end = timeval_sum(&time_now, &timeout);
- if (retry) {
- goto again;
- }
+ while (true) {
+#ifdef CLUSTER_SUPPORT
+ fd_set _r_fds;
+#endif
+ fd_set *r_fds = NULL;
+ int max_fd = 0;
+ int ret;
+ struct timeval timeout_remaining, select_timeout;
+
+ status = g_lock_trylock(ctx, name, lock_type);
+ if (NT_STATUS_IS_OK(status)) {
+ DEBUG(10, ("Got lock %s\n", name));
+ break;
+ }
+ if (!NT_STATUS_EQUAL(status, STATUS_PENDING)) {
+ DEBUG(10, ("g_lock_trylock failed: %s\n",
+ nt_errstr(status)));
+ break;
+ }
- DEBUG(10, ("g_lock_trylock: Did not get lock, waiting...\n"));
+ DEBUG(10, ("g_lock_trylock: Did not get lock, waiting...\n"));
+
+ /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * !!! HACK ALERT --- FIX ME !!!
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * What we really want to do here is to react to
+ * MSG_DBWRAP_G_LOCK_RETRY messages that are either sent
+ * by a client doing g_lock_unlock or by ourselves when
+ * we receive a CTDB_SRVID_SAMBA_NOTIFY or
+ * CTDB_SRVID_RECONFIGURE message from ctdbd, i.e. when
+ * either a client holding a lock or a complete node
+ * has died.
+ *
+ * Doing this properly involves calling tevent_loop_once(),
+ * but doing this here with the main ctdbd messaging context
+ * creates a nested event loop when g_lock_lock() is called
+ * from the main event loop, e.g. in a tcon_and_X where the
+ * share_info.tdb needs to be initialized and is locked by
+ * another process, or when the remore registry is accessed
+ * for writing and some other process already holds a lock
+ * on the registry.tdb.
+ *
+ * So as a quick fix, we act a little coarsely here: we do
+ * a select on the ctdb connection fd and when it is readable
+ * or we get EINTR, then we retry without actually parsing
+ * any ctdb packages or dispatching messages. This means that
+ * we retry more often than intended by design, but this does
+ * not harm and it is unobtrusive. When we have finished,
+ * the main loop will pick up all the messages and ctdb
+ * packets. The only extra twist is that we cannot use timed
+ * events here but have to handcode a timeout.
+ */
- if (te == NULL) {
- te = tevent_add_timer(
- ctx->msg->event_ctx, talloc_tos(),
- timeval_current_ofs(timeout.tv_sec, timeout.tv_usec),
- g_lock_timedout, &timedout);
- if (te == NULL) {
- DEBUG(10, ("tevent_add_timer failed\n"));
- status = NT_STATUS_NO_MEMORY;
- goto done;
+#ifdef CLUSTER_SUPPORT
+ if (lp_clustering()) {
+ struct ctdbd_connection *conn;
+ conn = messaging_ctdbd_connection();
+
+ r_fds = &_r_fds;
+ FD_ZERO(r_fds);
+ max_fd = ctdbd_conn_get_fd(conn);
+ FD_SET(max_fd, r_fds);
}
- }
+#endif
- while (true) {
- if (tevent_loop_once(ctx->msg->event_ctx) == -1) {
- DEBUG(1, ("tevent_loop_once failed\n"));
- status = NT_STATUS_INTERNAL_ERROR;
- goto done;
- }
- if (retry) {
- goto again;
- }
- if (timedout) {
- DEBUG(10, ("g_lock_lock timed out\n"));
+ time_now = timeval_current();
+ timeout_remaining = timeval_until(&time_now, &timeout_end);
+ select_timeout = timeval_set(60, 0);
- te = NULL;
+ select_timeout = timeval_min(&select_timeout,
+ &timeout_remaining);
- status = NT_STATUS_LOCK_NOT_GRANTED;
- goto done;
+ ret = sys_select(max_fd + 1, r_fds, NULL, NULL,
+ &select_timeout);
+ if (ret == -1) {
+ if (errno != EINTR) {
+ DEBUG(1, ("error calling select: %s\n",
+ strerror(errno)));
+ status = NT_STATUS_INTERNAL_ERROR;
+ break;
+ }
+ /*
+ * errno == EINTR:
+ * This means a signal was received.
+ * It might have been a MSG_DBWRAP_G_LOCK_RETRY message.
+ * ==> retry
+ */
+ } else if (ret == 0) {
+ if (timeval_expired(&timeout_end)) {
+ DEBUG(10, ("g_lock_lock timed out\n"));
+ status = NT_STATUS_LOCK_NOT_GRANTED;
+ break;
+ } else {
+ DEBUG(10, ("select returned 0 but timeout not "
+ "not expired, retrying\n"));
+ }
+ } else if (ret != 1) {
+ DEBUG(1, ("invalid return code of select: %d\n", ret));
+ status = NT_STATUS_INTERNAL_ERROR;
+ break;
}
+ /*
+ * ret == 1:
+ * This means ctdbd has sent us some data.
+ * Might be a CTDB_SRVID_RECONFIGURE or a
+ * CTDB_SRVID_SAMBA_NOTIFY message.
+ * ==> retry
+ */
}
+
+#ifdef CLUSTER_SUPPORT
done:
+#endif
if (!NT_STATUS_IS_OK(status)) {
NTSTATUS unlock_status;
*pretry = true;
}
-static void g_lock_timedout(struct tevent_context *ev,
- struct tevent_timer *te,
- struct timeval current_time,
- void *private_data)
-{
- bool *ptimedout = (bool *)private_data;
- *ptimedout = true;
- TALLOC_FREE(te);
-}
-
static NTSTATUS g_lock_force_unlock(struct g_lock_ctx *ctx, const char *name,
struct server_id pid)
{
goto done;
}
+ TALLOC_FREE(rec);
+
if ((lock_type & G_LOCK_PENDING) == 0) {
+ int num_wakeups = 0;
+
/*
- * We've been the lock holder. Tell all others to retry.
+ * We've been the lock holder. Others to retry. Don't
+ * tell all others to avoid a thundering herd. In case
+ * this leads to a complete stall because we miss some
+ * processes, the loop in g_lock_lock tries at least
+ * once a minute.
*/
+
for (i=0; i<num_locks; i++) {
if ((locks[i].lock_type & G_LOCK_PENDING) == 0) {
continue;
}
+ if (!process_exists(locks[i].pid)) {
+ continue;
+ }
/*
* Ping all waiters to retry
procid_str(talloc_tos(),
&locks[i].pid),
nt_errstr(status)));
+ } else {
+ num_wakeups += 1;
+ }
+ if (num_wakeups > 5) {
+ break;
}
}
}
done:
+ /*
+ * For the error path, TALLOC_FREE(rec) as well. In the good
+ * path we have already freed it.
+ */
+ TALLOC_FREE(rec);
TALLOC_FREE(locks);
- TALLOC_FREE(rec);
return status;
}
{
NTSTATUS status;
- status = g_lock_force_unlock(ctx, name, procid_self());
+ status = g_lock_force_unlock(ctx, name, messaging_server_id(ctx->msg));
#ifdef CLUSTER_SUPPORT
if (lp_clustering()) {
}
return NT_STATUS_OK;
}
+
+static bool g_lock_init_all(TALLOC_CTX *mem_ctx,
+ struct tevent_context **pev,
+ struct messaging_context **pmsg,
+ const struct server_id self,
+ struct g_lock_ctx **pg_ctx)
+{
+ struct tevent_context *ev = NULL;
+ struct messaging_context *msg = NULL;
+ struct g_lock_ctx *g_ctx = NULL;
+
+ ev = tevent_context_init(mem_ctx);
+ if (ev == NULL) {
+ d_fprintf(stderr, "ERROR: could not init event context\n");
+ goto fail;
+ }
+ msg = messaging_init(mem_ctx, self, ev);
+ if (msg == NULL) {
+ d_fprintf(stderr, "ERROR: could not init messaging context\n");
+ goto fail;
+ }
+ g_ctx = g_lock_ctx_init(mem_ctx, msg);
+ if (g_ctx == NULL) {
+ d_fprintf(stderr, "ERROR: could not init g_lock context\n");
+ goto fail;
+ }
+
+ *pev = ev;
+ *pmsg = msg;
+ *pg_ctx = g_ctx;
+ return true;
+fail:
+ TALLOC_FREE(g_ctx);
+ TALLOC_FREE(msg);
+ TALLOC_FREE(ev);
+ return false;
+}
+
+NTSTATUS g_lock_do(const char *name, enum g_lock_type lock_type,
+ struct timeval timeout, const struct server_id self,
+ void (*fn)(void *private_data), void *private_data)
+{
+ struct tevent_context *ev = NULL;
+ struct messaging_context *msg = NULL;
+ struct g_lock_ctx *g_ctx = NULL;
+ NTSTATUS status;
+
+ if (!g_lock_init_all(talloc_tos(), &ev, &msg, self, &g_ctx)) {
+ status = NT_STATUS_ACCESS_DENIED;
+ goto done;
+ }
+
+ status = g_lock_lock(g_ctx, name, lock_type, timeout);
+ if (!NT_STATUS_IS_OK(status)) {
+ goto done;
+ }
+ fn(private_data);
+ g_lock_unlock(g_ctx, name);
+
+done:
+ TALLOC_FREE(g_ctx);
+ TALLOC_FREE(msg);
+ TALLOC_FREE(ev);
+ return status;
+}
git.samba.org / samba.git / blobdiff