diff options
| -rw-r--r-- | source3/lib/g_lock.c | 139 |
1 files changed, 101 insertions, 38 deletions
diff --git a/source3/lib/g_lock.c b/source3/lib/g_lock.c index 0eae3f2131e..8a44b22e11f 100644 --- a/source3/lib/g_lock.c +++ b/source3/lib/g_lock.c @@ -266,7 +266,9 @@ NTSTATUS g_lock_lock(struct g_lock_ctx *ctx, const char *name, struct tevent_timer *te = NULL; NTSTATUS status; bool retry = false; - bool timedout = false; + struct timeval timeout_end; + struct timeval timeout_remaining; + struct timeval time_now; DEBUG(10, ("Trying to acquire lock %d for %s\n", (int)lock_type, name)); @@ -295,52 +297,113 @@ NTSTATUS g_lock_lock(struct g_lock_ctx *ctx, const char *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; - } - - DEBUG(10, ("g_lock_trylock: Did not get lock, waiting...\n")); - - 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; - } - } + time_now = timeval_current(); + timeout_end = timeval_sum(&time_now, &timeout); 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; + fd_set _r_fds; + fd_set *r_fds = NULL; + int max_fd = 0; + int ret; + + 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; } - if (retry) { - goto again; + + 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 corasely 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. + */ + +#ifdef CLUSTER_SUPPORT + if (lp_clustering()) { + struct ctdbd_connection *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); } - if (timedout) { - DEBUG(10, ("g_lock_lock timed out\n")); +#endif - te = NULL; + time_now = timeval_current(); + timeout_remaining = timeval_until(&time_now, &timeout_end); - status = NT_STATUS_LOCK_NOT_GRANTED; - goto done; + ret = sys_select(max_fd + 1, r_fds, NULL, NULL, + &timeout_remaining); + + 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: strange - 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 + */ } + done: if (!NT_STATUS_IS_OK(status)) { |