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335 lines
11 KiB
335 lines
11 KiB
/* SPDX-License-Identifier: GPL-2.0-or-later */ |
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/* |
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drbd_req.h |
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This file is part of DRBD by Philipp Reisner and Lars Ellenberg. |
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Copyright (C) 2006-2008, LINBIT Information Technologies GmbH. |
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Copyright (C) 2006-2008, Lars Ellenberg <[email protected]>. |
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Copyright (C) 2006-2008, Philipp Reisner <[email protected]>. |
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*/ |
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#ifndef _DRBD_REQ_H |
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#define _DRBD_REQ_H |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/drbd.h> |
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#include "drbd_int.h" |
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/* The request callbacks will be called in irq context by the IDE drivers, |
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and in Softirqs/Tasklets/BH context by the SCSI drivers, |
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and by the receiver and worker in kernel-thread context. |
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Try to get the locking right :) */ |
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/* |
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* Objects of type struct drbd_request do only exist on a R_PRIMARY node, and are |
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* associated with IO requests originating from the block layer above us. |
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* |
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* There are quite a few things that may happen to a drbd request |
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* during its lifetime. |
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* |
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* It will be created. |
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* It will be marked with the intention to be |
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* submitted to local disk and/or |
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* send via the network. |
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* |
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* It has to be placed on the transfer log and other housekeeping lists, |
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* In case we have a network connection. |
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* |
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* It may be identified as a concurrent (write) request |
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* and be handled accordingly. |
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* |
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* It may me handed over to the local disk subsystem. |
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* It may be completed by the local disk subsystem, |
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* either successfully or with io-error. |
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* In case it is a READ request, and it failed locally, |
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* it may be retried remotely. |
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* |
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* It may be queued for sending. |
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* It may be handed over to the network stack, |
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* which may fail. |
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* It may be acknowledged by the "peer" according to the wire_protocol in use. |
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* this may be a negative ack. |
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* It may receive a faked ack when the network connection is lost and the |
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* transfer log is cleaned up. |
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* Sending may be canceled due to network connection loss. |
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* When it finally has outlived its time, |
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* corresponding dirty bits in the resync-bitmap may be cleared or set, |
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* it will be destroyed, |
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* and completion will be signalled to the originator, |
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* with or without "success". |
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*/ |
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enum drbd_req_event { |
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CREATED, |
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TO_BE_SENT, |
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TO_BE_SUBMITTED, |
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/* XXX yes, now I am inconsistent... |
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* these are not "events" but "actions" |
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* oh, well... */ |
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QUEUE_FOR_NET_WRITE, |
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QUEUE_FOR_NET_READ, |
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QUEUE_FOR_SEND_OOS, |
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/* An empty flush is queued as P_BARRIER, |
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* which will cause it to complete "successfully", |
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* even if the local disk flush failed. |
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* |
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* Just like "real" requests, empty flushes (blkdev_issue_flush()) will |
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* only see an error if neither local nor remote data is reachable. */ |
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QUEUE_AS_DRBD_BARRIER, |
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SEND_CANCELED, |
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SEND_FAILED, |
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HANDED_OVER_TO_NETWORK, |
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OOS_HANDED_TO_NETWORK, |
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CONNECTION_LOST_WHILE_PENDING, |
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READ_RETRY_REMOTE_CANCELED, |
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RECV_ACKED_BY_PEER, |
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WRITE_ACKED_BY_PEER, |
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WRITE_ACKED_BY_PEER_AND_SIS, /* and set_in_sync */ |
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CONFLICT_RESOLVED, |
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POSTPONE_WRITE, |
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NEG_ACKED, |
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BARRIER_ACKED, /* in protocol A and B */ |
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DATA_RECEIVED, /* (remote read) */ |
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COMPLETED_OK, |
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READ_COMPLETED_WITH_ERROR, |
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READ_AHEAD_COMPLETED_WITH_ERROR, |
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WRITE_COMPLETED_WITH_ERROR, |
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DISCARD_COMPLETED_NOTSUPP, |
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DISCARD_COMPLETED_WITH_ERROR, |
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ABORT_DISK_IO, |
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RESEND, |
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FAIL_FROZEN_DISK_IO, |
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RESTART_FROZEN_DISK_IO, |
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NOTHING, |
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}; |
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/* encoding of request states for now. we don't actually need that many bits. |
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* we don't need to do atomic bit operations either, since most of the time we |
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* need to look at the connection state and/or manipulate some lists at the |
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* same time, so we should hold the request lock anyways. |
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*/ |
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enum drbd_req_state_bits { |
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/* 3210 |
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* 0000: no local possible |
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* 0001: to be submitted |
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* UNUSED, we could map: 011: submitted, completion still pending |
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* 0110: completed ok |
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* 0010: completed with error |
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* 1001: Aborted (before completion) |
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* 1x10: Aborted and completed -> free |
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*/ |
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__RQ_LOCAL_PENDING, |
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__RQ_LOCAL_COMPLETED, |
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__RQ_LOCAL_OK, |
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__RQ_LOCAL_ABORTED, |
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/* 87654 |
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* 00000: no network possible |
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* 00001: to be send |
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* 00011: to be send, on worker queue |
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* 00101: sent, expecting recv_ack (B) or write_ack (C) |
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* 11101: sent, |
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* recv_ack (B) or implicit "ack" (A), |
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* still waiting for the barrier ack. |
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* master_bio may already be completed and invalidated. |
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* 11100: write acked (C), |
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* data received (for remote read, any protocol) |
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* or finally the barrier ack has arrived (B,A)... |
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* request can be freed |
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* 01100: neg-acked (write, protocol C) |
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* or neg-d-acked (read, any protocol) |
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* or killed from the transfer log |
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* during cleanup after connection loss |
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* request can be freed |
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* 01000: canceled or send failed... |
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* request can be freed |
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*/ |
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/* if "SENT" is not set, yet, this can still fail or be canceled. |
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* if "SENT" is set already, we still wait for an Ack packet. |
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* when cleared, the master_bio may be completed. |
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* in (B,A) the request object may still linger on the transaction log |
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* until the corresponding barrier ack comes in */ |
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__RQ_NET_PENDING, |
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/* If it is QUEUED, and it is a WRITE, it is also registered in the |
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* transfer log. Currently we need this flag to avoid conflicts between |
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* worker canceling the request and tl_clear_barrier killing it from |
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* transfer log. We should restructure the code so this conflict does |
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* no longer occur. */ |
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__RQ_NET_QUEUED, |
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/* well, actually only "handed over to the network stack". |
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* |
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* TODO can potentially be dropped because of the similar meaning |
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* of RQ_NET_SENT and ~RQ_NET_QUEUED. |
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* however it is not exactly the same. before we drop it |
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* we must ensure that we can tell a request with network part |
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* from a request without, regardless of what happens to it. */ |
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__RQ_NET_SENT, |
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/* when set, the request may be freed (if RQ_NET_QUEUED is clear). |
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* basically this means the corresponding P_BARRIER_ACK was received */ |
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__RQ_NET_DONE, |
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/* whether or not we know (C) or pretend (B,A) that the write |
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* was successfully written on the peer. |
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*/ |
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__RQ_NET_OK, |
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/* peer called drbd_set_in_sync() for this write */ |
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__RQ_NET_SIS, |
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/* keep this last, its for the RQ_NET_MASK */ |
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__RQ_NET_MAX, |
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/* Set when this is a write, clear for a read */ |
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__RQ_WRITE, |
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__RQ_WSAME, |
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__RQ_UNMAP, |
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__RQ_ZEROES, |
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/* Should call drbd_al_complete_io() for this request... */ |
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__RQ_IN_ACT_LOG, |
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/* This was the most recent request during some blk_finish_plug() |
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* or its implicit from-schedule equivalent. |
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* We may use it as hint to send a P_UNPLUG_REMOTE */ |
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__RQ_UNPLUG, |
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/* The peer has sent a retry ACK */ |
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__RQ_POSTPONED, |
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/* would have been completed, |
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* but was not, because of drbd_suspended() */ |
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__RQ_COMPLETION_SUSP, |
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/* We expect a receive ACK (wire proto B) */ |
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__RQ_EXP_RECEIVE_ACK, |
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/* We expect a write ACK (wite proto C) */ |
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__RQ_EXP_WRITE_ACK, |
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/* waiting for a barrier ack, did an extra kref_get */ |
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__RQ_EXP_BARR_ACK, |
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}; |
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#define RQ_LOCAL_PENDING (1UL << __RQ_LOCAL_PENDING) |
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#define RQ_LOCAL_COMPLETED (1UL << __RQ_LOCAL_COMPLETED) |
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#define RQ_LOCAL_OK (1UL << __RQ_LOCAL_OK) |
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#define RQ_LOCAL_ABORTED (1UL << __RQ_LOCAL_ABORTED) |
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#define RQ_LOCAL_MASK ((RQ_LOCAL_ABORTED << 1)-1) |
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#define RQ_NET_PENDING (1UL << __RQ_NET_PENDING) |
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#define RQ_NET_QUEUED (1UL << __RQ_NET_QUEUED) |
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#define RQ_NET_SENT (1UL << __RQ_NET_SENT) |
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#define RQ_NET_DONE (1UL << __RQ_NET_DONE) |
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#define RQ_NET_OK (1UL << __RQ_NET_OK) |
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#define RQ_NET_SIS (1UL << __RQ_NET_SIS) |
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#define RQ_NET_MASK (((1UL << __RQ_NET_MAX)-1) & ~RQ_LOCAL_MASK) |
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#define RQ_WRITE (1UL << __RQ_WRITE) |
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#define RQ_WSAME (1UL << __RQ_WSAME) |
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#define RQ_UNMAP (1UL << __RQ_UNMAP) |
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#define RQ_ZEROES (1UL << __RQ_ZEROES) |
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#define RQ_IN_ACT_LOG (1UL << __RQ_IN_ACT_LOG) |
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#define RQ_UNPLUG (1UL << __RQ_UNPLUG) |
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#define RQ_POSTPONED (1UL << __RQ_POSTPONED) |
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#define RQ_COMPLETION_SUSP (1UL << __RQ_COMPLETION_SUSP) |
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#define RQ_EXP_RECEIVE_ACK (1UL << __RQ_EXP_RECEIVE_ACK) |
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#define RQ_EXP_WRITE_ACK (1UL << __RQ_EXP_WRITE_ACK) |
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#define RQ_EXP_BARR_ACK (1UL << __RQ_EXP_BARR_ACK) |
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/* For waking up the frozen transfer log mod_req() has to return if the request |
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should be counted in the epoch object*/ |
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#define MR_WRITE 1 |
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#define MR_READ 2 |
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static inline void drbd_req_make_private_bio(struct drbd_request *req, struct bio *bio_src) |
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{ |
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struct bio *bio; |
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bio = bio_clone_fast(bio_src, GFP_NOIO, &drbd_io_bio_set); |
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req->private_bio = bio; |
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bio->bi_private = req; |
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bio->bi_end_io = drbd_request_endio; |
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bio->bi_next = NULL; |
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} |
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/* Short lived temporary struct on the stack. |
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* We could squirrel the error to be returned into |
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* bio->bi_iter.bi_size, or similar. But that would be too ugly. */ |
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struct bio_and_error { |
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struct bio *bio; |
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int error; |
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}; |
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extern void start_new_tl_epoch(struct drbd_connection *connection); |
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extern void drbd_req_destroy(struct kref *kref); |
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extern void _req_may_be_done(struct drbd_request *req, |
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struct bio_and_error *m); |
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extern int __req_mod(struct drbd_request *req, enum drbd_req_event what, |
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struct bio_and_error *m); |
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extern void complete_master_bio(struct drbd_device *device, |
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struct bio_and_error *m); |
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extern void request_timer_fn(struct timer_list *t); |
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extern void tl_restart(struct drbd_connection *connection, enum drbd_req_event what); |
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extern void _tl_restart(struct drbd_connection *connection, enum drbd_req_event what); |
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extern void tl_abort_disk_io(struct drbd_device *device); |
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/* this is in drbd_main.c */ |
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extern void drbd_restart_request(struct drbd_request *req); |
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/* use this if you don't want to deal with calling complete_master_bio() |
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* outside the spinlock, e.g. when walking some list on cleanup. */ |
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static inline int _req_mod(struct drbd_request *req, enum drbd_req_event what) |
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{ |
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struct drbd_device *device = req->device; |
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struct bio_and_error m; |
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int rv; |
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/* __req_mod possibly frees req, do not touch req after that! */ |
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rv = __req_mod(req, what, &m); |
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if (m.bio) |
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complete_master_bio(device, &m); |
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return rv; |
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} |
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/* completion of master bio is outside of our spinlock. |
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* We still may or may not be inside some irqs disabled section |
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* of the lower level driver completion callback, so we need to |
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* spin_lock_irqsave here. */ |
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static inline int req_mod(struct drbd_request *req, |
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enum drbd_req_event what) |
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{ |
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unsigned long flags; |
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struct drbd_device *device = req->device; |
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struct bio_and_error m; |
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int rv; |
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spin_lock_irqsave(&device->resource->req_lock, flags); |
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rv = __req_mod(req, what, &m); |
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spin_unlock_irqrestore(&device->resource->req_lock, flags); |
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if (m.bio) |
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complete_master_bio(device, &m); |
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return rv; |
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} |
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extern bool drbd_should_do_remote(union drbd_dev_state); |
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#endif
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