/* 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 <lars.ellenberg@linbit.com>. Copyright (C) 2006-2008, Philipp Reisner <philipp.reisner@linbit.com>. */ #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 { CREATED, TO_BE_SENT, TO_BE_SUBMITTED, /* XXX yes, now I am inconsistent... * these are not "events" but "actions" * oh, well... */ QUEUE_FOR_NET_WRITE, QUEUE_FOR_NET_READ, QUEUE_FOR_SEND_OOS, /* An empty flush is queued as P_BARRIER, * which will cause it to complete "successfully", * even if the local disk flush failed. * * Just like "real" requests, empty flushes (blkdev_issue_flush()) will * only see an error if neither local nor remote data is reachable. */ QUEUE_AS_DRBD_BARRIER, SEND_CANCELED, SEND_FAILED, HANDED_OVER_TO_NETWORK, OOS_HANDED_TO_NETWORK, CONNECTION_LOST_WHILE_PENDING, READ_RETRY_REMOTE_CANCELED, RECV_ACKED_BY_PEER, WRITE_ACKED_BY_PEER, WRITE_ACKED_BY_PEER_AND_SIS, /* and set_in_sync */ CONFLICT_RESOLVED, POSTPONE_WRITE, NEG_ACKED, BARRIER_ACKED, /* in protocol A and B */ DATA_RECEIVED, /* (remote read) */ COMPLETED_OK, READ_COMPLETED_WITH_ERROR, READ_AHEAD_COMPLETED_WITH_ERROR, WRITE_COMPLETED_WITH_ERROR, DISCARD_COMPLETED_NOTSUPP, DISCARD_COMPLETED_WITH_ERROR, ABORT_DISK_IO, RESEND, FAIL_FROZEN_DISK_IO, RESTART_FROZEN_DISK_IO, NOTHING, }; /* 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 { /* 3210 * 0000: no local possible * 0001: to be submitted * UNUSED, we could map: 011: submitted, completion still pending * 0110: completed ok * 0010: completed with error * 1001: Aborted (before completion) * 1x10: Aborted and completed -> free */ __RQ_LOCAL_PENDING, __RQ_LOCAL_COMPLETED, __RQ_LOCAL_OK, __RQ_LOCAL_ABORTED, /* 87654 * 00000: no network possible * 00001: to be send * 00011: to be send, on worker queue * 00101: sent, expecting recv_ack (B) or write_ack (C) * 11101: sent, * recv_ack (B) or implicit "ack" (A), * still waiting for the barrier ack. * master_bio may already be completed and invalidated. * 11100: write acked (C), * data received (for remote read, any protocol) * or finally the barrier ack has arrived (B,A)... * request can be freed * 01100: neg-acked (write, protocol C) * or neg-d-acked (read, any protocol) * or killed from the transfer log * during cleanup after connection loss * request can be freed * 01000: canceled or send failed... * request can be freed */ /* if "SENT" is not set, yet, this can still fail or be canceled. * if "SENT" is set already, we still wait for an Ack packet. * when cleared, the master_bio may be completed. * in (B,A) the request object may still linger on the transaction log * until the corresponding barrier ack comes in */ __RQ_NET_PENDING, /* If it is QUEUED, and it is a WRITE, it is also registered in the * transfer log. Currently we need this flag to avoid conflicts between * worker canceling the request and tl_clear_barrier killing it from * transfer log. We should restructure the code so this conflict does * no longer occur. */ __RQ_NET_QUEUED, /* well, actually only "handed over to the network stack". * * TODO can potentially be dropped because of the similar meaning * of RQ_NET_SENT and ~RQ_NET_QUEUED. * however it is not exactly the same. before we drop it * we must ensure that we can tell a request with network part * from a request without, regardless of what happens to it. */ __RQ_NET_SENT, /* when set, the request may be freed (if RQ_NET_QUEUED is clear). * basically this means the corresponding P_BARRIER_ACK was received */ __RQ_NET_DONE, /* whether or not we know (C) or pretend (B,A) that the write * was successfully written on the peer. */ __RQ_NET_OK, /* peer called drbd_set_in_sync() for this write */ __RQ_NET_SIS, /* keep this last, its for the RQ_NET_MASK */ __RQ_NET_MAX, /* Set when this is a write, clear for a read */ __RQ_WRITE, __RQ_WSAME, __RQ_UNMAP, __RQ_ZEROES, /* Should call drbd_al_complete_io() for this request... */ __RQ_IN_ACT_LOG, /* This was the most recent request during some blk_finish_plug() * or its implicit from-schedule equivalent. * We may use it as hint to send a P_UNPLUG_REMOTE */ __RQ_UNPLUG, /* The peer has sent a retry ACK */ __RQ_POSTPONED, /* would have been completed, * but was not, because of drbd_suspended() */ __RQ_COMPLETION_SUSP, /* We expect a receive ACK (wire proto B) */ __RQ_EXP_RECEIVE_ACK, /* We expect a write ACK (wite proto C) */ __RQ_EXP_WRITE_ACK, /* waiting for a barrier ack, did an extra kref_get */ __RQ_EXP_BARR_ACK, }; #define RQ_LOCAL_PENDING (1UL << __RQ_LOCAL_PENDING) #define RQ_LOCAL_COMPLETED (1UL << __RQ_LOCAL_COMPLETED) #define RQ_LOCAL_OK (1UL << __RQ_LOCAL_OK) #define RQ_LOCAL_ABORTED (1UL << __RQ_LOCAL_ABORTED) #define RQ_LOCAL_MASK ((RQ_LOCAL_ABORTED << 1)-1) #define RQ_NET_PENDING (1UL << __RQ_NET_PENDING) #define RQ_NET_QUEUED (1UL << __RQ_NET_QUEUED) #define RQ_NET_SENT (1UL << __RQ_NET_SENT) #define RQ_NET_DONE (1UL << __RQ_NET_DONE) #define RQ_NET_OK (1UL << __RQ_NET_OK) #define RQ_NET_SIS (1UL << __RQ_NET_SIS) #define RQ_NET_MASK (((1UL << __RQ_NET_MAX)-1) & ~RQ_LOCAL_MASK) #define RQ_WRITE (1UL << __RQ_WRITE) #define RQ_WSAME (1UL << __RQ_WSAME) #define RQ_UNMAP (1UL << __RQ_UNMAP) #define RQ_ZEROES (1UL << __RQ_ZEROES) #define RQ_IN_ACT_LOG (1UL << __RQ_IN_ACT_LOG) #define RQ_UNPLUG (1UL << __RQ_UNPLUG) #define RQ_POSTPONED (1UL << __RQ_POSTPONED) #define RQ_COMPLETION_SUSP (1UL << __RQ_COMPLETION_SUSP) #define RQ_EXP_RECEIVE_ACK (1UL << __RQ_EXP_RECEIVE_ACK) #define RQ_EXP_WRITE_ACK (1UL << __RQ_EXP_WRITE_ACK) #define RQ_EXP_BARR_ACK (1UL << __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 1 #define MR_READ 2 /* 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 { struct bio *bio; int 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) { struct drbd_device *device = req->device; struct bio_and_error m; int rv; /* __req_mod possibly frees req, do not touch req after that! */ rv = __req_mod(req, what, peer_device, &m); if (m.bio) complete_master_bio(device, &m); return rv; } /* 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) { unsigned long flags; struct drbd_device *device = req->device; struct bio_and_error m; int rv; spin_lock_irqsave(&device->resource->req_lock, flags); rv = __req_mod(req, what, peer_device, &m); spin_unlock_irqrestore(&device->resource->req_lock, flags); if (m.bio) complete_master_bio(device, &m); return rv; } extern bool drbd_should_do_remote(union drbd_dev_state); #endif