| /* |
| 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>. |
| |
| DRBD is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| DRBD is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with drbd; see the file COPYING. If not, write to |
| the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
| */ |
| |
| #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, |
| |
| /* Should call drbd_al_complete_io() for this request... */ |
| __RQ_IN_ACT_LOG, |
| |
| /* 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_IN_ACT_LOG (1UL << __RQ_IN_ACT_LOG) |
| #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 |
| |
| static inline void drbd_req_make_private_bio(struct drbd_request *req, struct bio *bio_src) |
| { |
| struct bio *bio; |
| bio = bio_clone_fast(bio_src, GFP_NOIO, drbd_io_bio_set); |
| |
| req->private_bio = bio; |
| |
| bio->bi_private = req; |
| bio->bi_end_io = drbd_request_endio; |
| bio->bi_next = NULL; |
| } |
| |
| /* 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 void _req_may_be_done(struct drbd_request *req, |
| struct bio_and_error *m); |
| extern int __req_mod(struct drbd_request *req, enum drbd_req_event what, |
| struct bio_and_error *m); |
| extern void complete_master_bio(struct drbd_device *device, |
| struct bio_and_error *m); |
| extern void request_timer_fn(unsigned long data); |
| 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_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, &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) |
| { |
| 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, &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 |