/* SPDX-License-Identifier: GPL-2.0-only */ /* drbd_req.h This file is part of DRBD by Philipp Reisner and Lars Ellenberg. Copyright (C) 2006-2008, LINBIT Information Technologies GmbH. Copyright (C) 2006-2008, Lars Ellenberg <[email protected]>. Copyright (C) 2006-2008, Philipp Reisner <[email protected]>. */ #ifndef _DRBD_REQ_H #define _DRBD_REQ_H #include <linux/module.h> #include <linux/slab.h> #include <linux/drbd.h> #include "drbd_int.h" /* The request callbacks will be called in irq context by the IDE drivers, and in Softirqs/Tasklets/BH context by the SCSI drivers, and by the receiver and worker in kernel-thread context. Try to get the locking right :) */ /* * Objects of type struct drbd_request do only exist on a R_PRIMARY node, and are * associated with IO requests originating from the block layer above us. * * There are quite a few things that may happen to a drbd request * during its lifetime. * * It will be created. * It will be marked with the intention to be * submitted to local disk and/or * send via the network. * * It has to be placed on the transfer log and other housekeeping lists, * In case we have a network connection. * * It may be identified as a concurrent (write) request * and be handled accordingly. * * It may me handed over to the local disk subsystem. * It may be completed by the local disk subsystem, * either successfully or with io-error. * In case it is a READ request, and it failed locally, * it may be retried remotely. * * It may be queued for sending. * It may be handed over to the network stack, * which may fail. * It may be acknowledged by the "peer" according to the wire_protocol in use. * this may be a negative ack. * It may receive a faked ack when the network connection is lost and the * transfer log is cleaned up. * Sending may be canceled due to network connection loss. * When it finally has outlived its time, * corresponding dirty bits in the resync-bitmap may be cleared or set, * it will be destroyed, * and completion will be signalled to the originator, * with or without "success". */ enum drbd_req_event { … }; /* encoding of request states for now. we don't actually need that many bits. * we don't need to do atomic bit operations either, since most of the time we * need to look at the connection state and/or manipulate some lists at the * same time, so we should hold the request lock anyways. */ enum drbd_req_state_bits { … }; #define RQ_LOCAL_PENDING … #define RQ_LOCAL_COMPLETED … #define RQ_LOCAL_OK … #define RQ_LOCAL_ABORTED … #define RQ_LOCAL_MASK … #define RQ_NET_PENDING … #define RQ_NET_QUEUED … #define RQ_NET_SENT … #define RQ_NET_DONE … #define RQ_NET_OK … #define RQ_NET_SIS … #define RQ_NET_MASK … #define RQ_WRITE … #define RQ_WSAME … #define RQ_UNMAP … #define RQ_ZEROES … #define RQ_IN_ACT_LOG … #define RQ_UNPLUG … #define RQ_POSTPONED … #define RQ_COMPLETION_SUSP … #define RQ_EXP_RECEIVE_ACK … #define RQ_EXP_WRITE_ACK … #define RQ_EXP_BARR_ACK … /* For waking up the frozen transfer log mod_req() has to return if the request should be counted in the epoch object*/ #define MR_WRITE … #define MR_READ … /* Short lived temporary struct on the stack. * We could squirrel the error to be returned into * bio->bi_iter.bi_size, or similar. But that would be too ugly. */ struct bio_and_error { … }; extern void start_new_tl_epoch(struct drbd_connection *connection); extern void drbd_req_destroy(struct kref *kref); extern int __req_mod(struct drbd_request *req, enum drbd_req_event what, struct drbd_peer_device *peer_device, struct bio_and_error *m); extern void complete_master_bio(struct drbd_device *device, struct bio_and_error *m); extern void request_timer_fn(struct timer_list *t); extern void tl_restart(struct drbd_connection *connection, enum drbd_req_event what); extern void _tl_restart(struct drbd_connection *connection, enum drbd_req_event what); extern void tl_abort_disk_io(struct drbd_device *device); /* this is in drbd_main.c */ extern void drbd_restart_request(struct drbd_request *req); /* use this if you don't want to deal with calling complete_master_bio() * outside the spinlock, e.g. when walking some list on cleanup. */ static inline int _req_mod(struct drbd_request *req, enum drbd_req_event what, struct drbd_peer_device *peer_device) { … } /* completion of master bio is outside of our spinlock. * We still may or may not be inside some irqs disabled section * of the lower level driver completion callback, so we need to * spin_lock_irqsave here. */ static inline int req_mod(struct drbd_request *req, enum drbd_req_event what, struct drbd_peer_device *peer_device) { … } extern bool drbd_should_do_remote(union drbd_dev_state); #endif
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