6 #include "index-session.h"
15 #include "index.h"
16 #include "index-layout.h"
19  * The index session contains a lock (the request_mutex) which ensures that only one thread can
20  * change the state of its index at a time. The state field indicates the current state of the
21  * index through a set of descriptive flags. The request_mutex must be notified whenever a
23  * requests currently in progress so that they can be drained when suspending or closing the index.
25  * If the index session is suspended shortly after opening an index, it may have to suspend during
26  * a rebuild. Depending on the size of the index, a rebuild may take a significant amount of time,
28  * the index session is resumed, the rebuild can continue from where it left off. If the index
30  * will start from the beginning the next time the index is loaded. The mutex and status fields in
36 	/* The session has started loading an index but not completed it. */
38 	/* The session has loaded an index, which can handle requests. */
40 	/* The session's index has been permanently disabled. */
42 	/* The session's index is suspended. */
44 	/* The session is handling some index state change. */
46 	/* The session's index is closing and draining requests. */
62 /* Release a reference to an index session. */
72  * Acquire a reference to the index session for an asynchronous index request. The reference must
131 	request->index = request->session->index;  in uds_launch_request()
256 		vdo_log_info("Index session is suspended");  in start_loading_index_session()
259 		vdo_log_info("Index is already loaded");  in start_loading_index_session()
295 				enter_callback_stage, &index_session->index);  in initialize_index_session()
297 		vdo_log_error_strerror(result, "Failed to make index");  in initialize_index_session()
309 		return "creating index";  in get_open_type_string()
311 		return "loading or rebuilding index";  in get_open_type_string()
313 		return "loading index";  in get_open_type_string()
320  * Open an index under the given session. This operation will fail if the
321  * index session is suspended, or if there is already an open index.
373 	return uds_save_index(index_session->index);  in save_index()
383 		/* Wait until the index indicates that it is not replaying. */  in suspend_rebuild()
393 		/* Index load does not need to be suspended. */  in suspend_rebuild()
409  * Suspend index operation, draining all current index requests and preventing new index requests
410  * from starting. Optionally saves all index data before returning.
418 	/* Wait for any current index state change to complete. */  in uds_suspend_index_session()
425 		vdo_log_info("Index session is already changing state");  in uds_suspend_index_session()
463 	result = uds_replace_index_storage(session->index, bdev);  in replace_device()
472  * Resume index operation after being suspended. If the index is suspended and the supplied block
473  * device differs from the current backing store, the index will start using the new backing store.
484 		vdo_log_info("Index session is already changing state");  in uds_resume_index_session()
501 	if ((session->index != NULL) && (bdev != session->parameters.bdev)) {  in uds_resume_index_session()
517 			/* Notify the index to start replaying again. */  in uds_resume_index_session()
522 			/* There is no index rebuild to resume. */  in uds_resume_index_session()
549 	struct uds_index *index = index_session->index;  in save_and_free_index()  local
551 	if (index == NULL)  in save_and_free_index()
559 		result = uds_save_index(index);  in save_and_free_index()
564 	uds_free_index(index);  in save_and_free_index()
565 	index_session->index = NULL;  in save_and_free_index()
568 	 * Reset all index state that happens to be in the index  in save_and_free_index()
569 	 * session, so it doesn't affect any future index.  in save_and_free_index()
583 /* Save and close the current index. */
588 	/* Wait for any current index state change to complete. */  in uds_close_index()
597 		vdo_log_info("Index session is suspended");  in uds_close_index()
601 		/* The index doesn't exist, hasn't finished loading, or is being destroyed. */  in uds_close_index()
610 	vdo_log_debug("Closing index");  in uds_close_index()
613 	vdo_log_debug("Closed index");  in uds_close_index()
622 /* This will save and close an open index before destroying the session. */
628 	vdo_log_debug("Destroying index session");  in uds_destroy_index_session()
630 	/* Wait for any current index state change to complete. */  in uds_destroy_index_session()
640 		vdo_log_info("Index session is already closing");  in uds_destroy_index_session()
650 		/* Tell the index to terminate the rebuild. */  in uds_destroy_index_session()
671 	vdo_log_debug("Destroyed index session");  in uds_destroy_index_session()
676 /* Wait until all callbacks for index operations are complete. */
680 	uds_wait_for_idle_index(index_session->index);  in uds_flush_index_session()
709 		vdo_log_error("received a NULL index stats pointer");  in uds_get_index_session_stats()
714 	if (index_session->index != NULL) {  in uds_get_index_session_stats()
715 		uds_get_index_stats(index_session->index, stats);  in uds_get_index_session_stats()