1166 lines
36 KiB
C
1166 lines
36 KiB
C
/*
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drbd_req.c
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This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
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Copyright (C) 2001-2008, LINBIT Information Technologies GmbH.
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Copyright (C) 1999-2008, Philipp Reisner <philipp.reisner@linbit.com>.
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Copyright (C) 2002-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
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drbd is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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drbd is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with drbd; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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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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#include "drbd_req.h"
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/* Update disk stats at start of I/O request */
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static void _drbd_start_io_acct(struct drbd_conf *mdev, struct drbd_request *req, struct bio *bio)
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{
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const int rw = bio_data_dir(bio);
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int cpu;
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cpu = part_stat_lock();
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part_stat_inc(cpu, &mdev->vdisk->part0, ios[rw]);
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part_stat_add(cpu, &mdev->vdisk->part0, sectors[rw], bio_sectors(bio));
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part_inc_in_flight(&mdev->vdisk->part0, rw);
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part_stat_unlock();
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}
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/* Update disk stats when completing request upwards */
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static void _drbd_end_io_acct(struct drbd_conf *mdev, struct drbd_request *req)
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{
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int rw = bio_data_dir(req->master_bio);
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unsigned long duration = jiffies - req->start_time;
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int cpu;
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cpu = part_stat_lock();
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part_stat_add(cpu, &mdev->vdisk->part0, ticks[rw], duration);
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part_round_stats(cpu, &mdev->vdisk->part0);
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part_dec_in_flight(&mdev->vdisk->part0, rw);
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part_stat_unlock();
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}
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static struct drbd_request *drbd_req_new(struct drbd_conf *mdev,
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struct bio *bio_src)
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{
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struct drbd_request *req;
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req = mempool_alloc(drbd_request_mempool, GFP_NOIO);
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if (!req)
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return NULL;
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drbd_req_make_private_bio(req, bio_src);
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req->rq_state = bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0;
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req->w.mdev = mdev;
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req->master_bio = bio_src;
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req->epoch = 0;
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drbd_clear_interval(&req->i);
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req->i.sector = bio_src->bi_sector;
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req->i.size = bio_src->bi_size;
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req->i.local = true;
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req->i.waiting = false;
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INIT_LIST_HEAD(&req->tl_requests);
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INIT_LIST_HEAD(&req->w.list);
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return req;
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}
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static void drbd_req_free(struct drbd_request *req)
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{
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mempool_free(req, drbd_request_mempool);
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}
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/* rw is bio_data_dir(), only READ or WRITE */
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static void _req_is_done(struct drbd_conf *mdev, struct drbd_request *req, const int rw)
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{
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const unsigned long s = req->rq_state;
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/* remove it from the transfer log.
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* well, only if it had been there in the first
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* place... if it had not (local only or conflicting
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* and never sent), it should still be "empty" as
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* initialized in drbd_req_new(), so we can list_del() it
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* here unconditionally */
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list_del(&req->tl_requests);
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/* if it was a write, we may have to set the corresponding
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* bit(s) out-of-sync first. If it had a local part, we need to
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* release the reference to the activity log. */
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if (rw == WRITE) {
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/* Set out-of-sync unless both OK flags are set
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* (local only or remote failed).
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* Other places where we set out-of-sync:
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* READ with local io-error */
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if (!(s & RQ_NET_OK) || !(s & RQ_LOCAL_OK))
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drbd_set_out_of_sync(mdev, req->i.sector, req->i.size);
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if ((s & RQ_NET_OK) && (s & RQ_LOCAL_OK) && (s & RQ_NET_SIS))
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drbd_set_in_sync(mdev, req->i.sector, req->i.size);
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/* one might be tempted to move the drbd_al_complete_io
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* to the local io completion callback drbd_endio_pri.
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* but, if this was a mirror write, we may only
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* drbd_al_complete_io after this is RQ_NET_DONE,
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* otherwise the extent could be dropped from the al
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* before it has actually been written on the peer.
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* if we crash before our peer knows about the request,
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* but after the extent has been dropped from the al,
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* we would forget to resync the corresponding extent.
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*/
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if (s & RQ_LOCAL_MASK) {
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if (get_ldev_if_state(mdev, D_FAILED)) {
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if (s & RQ_IN_ACT_LOG)
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drbd_al_complete_io(mdev, req->i.sector);
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put_ldev(mdev);
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} else if (__ratelimit(&drbd_ratelimit_state)) {
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dev_warn(DEV, "Should have called drbd_al_complete_io(, %llu), "
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"but my Disk seems to have failed :(\n",
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(unsigned long long) req->i.sector);
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}
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}
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}
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drbd_req_free(req);
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}
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static void queue_barrier(struct drbd_conf *mdev)
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{
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struct drbd_tl_epoch *b;
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/* We are within the req_lock. Once we queued the barrier for sending,
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* we set the CREATE_BARRIER bit. It is cleared as soon as a new
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* barrier/epoch object is added. This is the only place this bit is
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* set. It indicates that the barrier for this epoch is already queued,
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* and no new epoch has been created yet. */
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if (test_bit(CREATE_BARRIER, &mdev->flags))
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return;
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b = mdev->tconn->newest_tle;
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b->w.cb = w_send_barrier;
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b->w.mdev = mdev;
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/* inc_ap_pending done here, so we won't
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* get imbalanced on connection loss.
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* dec_ap_pending will be done in got_BarrierAck
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* or (on connection loss) in tl_clear. */
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inc_ap_pending(mdev);
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drbd_queue_work(&mdev->tconn->data.work, &b->w);
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set_bit(CREATE_BARRIER, &mdev->flags);
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}
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static void _about_to_complete_local_write(struct drbd_conf *mdev,
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struct drbd_request *req)
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{
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const unsigned long s = req->rq_state;
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/* Before we can signal completion to the upper layers,
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* we may need to close the current epoch.
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* We can skip this, if this request has not even been sent, because we
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* did not have a fully established connection yet/anymore, during
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* bitmap exchange, or while we are C_AHEAD due to congestion policy.
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*/
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if (mdev->state.conn >= C_CONNECTED &&
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(s & RQ_NET_SENT) != 0 &&
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req->epoch == mdev->tconn->newest_tle->br_number)
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queue_barrier(mdev);
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}
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void complete_master_bio(struct drbd_conf *mdev,
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struct bio_and_error *m)
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{
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bio_endio(m->bio, m->error);
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dec_ap_bio(mdev);
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}
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static void drbd_remove_request_interval(struct rb_root *root,
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struct drbd_request *req)
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{
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struct drbd_conf *mdev = req->w.mdev;
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struct drbd_interval *i = &req->i;
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drbd_remove_interval(root, i);
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/* Wake up any processes waiting for this request to complete. */
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if (i->waiting)
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wake_up(&mdev->misc_wait);
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}
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/* Helper for __req_mod().
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* Set m->bio to the master bio, if it is fit to be completed,
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* or leave it alone (it is initialized to NULL in __req_mod),
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* if it has already been completed, or cannot be completed yet.
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* If m->bio is set, the error status to be returned is placed in m->error.
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*/
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void _req_may_be_done(struct drbd_request *req, struct bio_and_error *m)
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{
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const unsigned long s = req->rq_state;
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struct drbd_conf *mdev = req->w.mdev;
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/* only WRITES may end up here without a master bio (on barrier ack) */
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int rw = req->master_bio ? bio_data_dir(req->master_bio) : WRITE;
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/* we must not complete the master bio, while it is
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* still being processed by _drbd_send_zc_bio (drbd_send_dblock)
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* not yet acknowledged by the peer
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* not yet completed by the local io subsystem
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* these flags may get cleared in any order by
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* the worker,
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* the receiver,
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* the bio_endio completion callbacks.
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*/
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if (s & RQ_NET_QUEUED)
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return;
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if (s & RQ_NET_PENDING)
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return;
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if (s & RQ_LOCAL_PENDING)
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return;
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if (req->master_bio) {
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/* this is DATA_RECEIVED (remote read)
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* or protocol C P_WRITE_ACK
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* or protocol B P_RECV_ACK
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* or protocol A "HANDED_OVER_TO_NETWORK" (SendAck)
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* or canceled or failed,
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* or killed from the transfer log due to connection loss.
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*/
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/*
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* figure out whether to report success or failure.
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*
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* report success when at least one of the operations succeeded.
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* or, to put the other way,
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* only report failure, when both operations failed.
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*
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* what to do about the failures is handled elsewhere.
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* what we need to do here is just: complete the master_bio.
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*
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* local completion error, if any, has been stored as ERR_PTR
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* in private_bio within drbd_endio_pri.
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*/
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int ok = (s & RQ_LOCAL_OK) || (s & RQ_NET_OK);
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int error = PTR_ERR(req->private_bio);
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/* remove the request from the conflict detection
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* respective block_id verification hash */
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if (!drbd_interval_empty(&req->i)) {
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struct rb_root *root;
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if (rw == WRITE)
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root = &mdev->write_requests;
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else
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root = &mdev->read_requests;
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drbd_remove_request_interval(root, req);
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} else
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D_ASSERT((s & (RQ_NET_MASK & ~RQ_NET_DONE)) == 0);
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/* for writes we need to do some extra housekeeping */
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if (rw == WRITE)
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_about_to_complete_local_write(mdev, req);
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/* Update disk stats */
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_drbd_end_io_acct(mdev, req);
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m->error = ok ? 0 : (error ?: -EIO);
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m->bio = req->master_bio;
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req->master_bio = NULL;
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}
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if ((s & RQ_NET_MASK) == 0 || (s & RQ_NET_DONE)) {
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/* this is disconnected (local only) operation,
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* or protocol C P_WRITE_ACK,
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* or protocol A or B P_BARRIER_ACK,
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* or killed from the transfer log due to connection loss. */
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_req_is_done(mdev, req, rw);
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}
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/* else: network part and not DONE yet. that is
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* protocol A or B, barrier ack still pending... */
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}
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static void _req_may_be_done_not_susp(struct drbd_request *req, struct bio_and_error *m)
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{
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struct drbd_conf *mdev = req->w.mdev;
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if (!is_susp(mdev->state))
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_req_may_be_done(req, m);
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}
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/* obviously this could be coded as many single functions
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* instead of one huge switch,
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* or by putting the code directly in the respective locations
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* (as it has been before).
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*
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* but having it this way
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* enforces that it is all in this one place, where it is easier to audit,
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* it makes it obvious that whatever "event" "happens" to a request should
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* happen "atomically" within the req_lock,
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* and it enforces that we have to think in a very structured manner
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* about the "events" that may happen to a request during its life time ...
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*/
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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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{
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struct drbd_conf *mdev = req->w.mdev;
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int rv = 0;
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m->bio = NULL;
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switch (what) {
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default:
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dev_err(DEV, "LOGIC BUG in %s:%u\n", __FILE__ , __LINE__);
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break;
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/* does not happen...
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* initialization done in drbd_req_new
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case CREATED:
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break;
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*/
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case TO_BE_SENT: /* via network */
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/* reached via drbd_make_request_common
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* and from w_read_retry_remote */
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D_ASSERT(!(req->rq_state & RQ_NET_MASK));
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req->rq_state |= RQ_NET_PENDING;
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inc_ap_pending(mdev);
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break;
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case TO_BE_SUBMITTED: /* locally */
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/* reached via drbd_make_request_common */
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D_ASSERT(!(req->rq_state & RQ_LOCAL_MASK));
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req->rq_state |= RQ_LOCAL_PENDING;
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break;
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case COMPLETED_OK:
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if (bio_data_dir(req->master_bio) == WRITE)
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mdev->writ_cnt += req->i.size >> 9;
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else
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mdev->read_cnt += req->i.size >> 9;
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req->rq_state |= (RQ_LOCAL_COMPLETED|RQ_LOCAL_OK);
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req->rq_state &= ~RQ_LOCAL_PENDING;
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_req_may_be_done_not_susp(req, m);
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put_ldev(mdev);
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break;
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case WRITE_COMPLETED_WITH_ERROR:
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req->rq_state |= RQ_LOCAL_COMPLETED;
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req->rq_state &= ~RQ_LOCAL_PENDING;
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__drbd_chk_io_error(mdev, false);
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_req_may_be_done_not_susp(req, m);
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put_ldev(mdev);
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break;
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case READ_AHEAD_COMPLETED_WITH_ERROR:
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/* it is legal to fail READA */
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req->rq_state |= RQ_LOCAL_COMPLETED;
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req->rq_state &= ~RQ_LOCAL_PENDING;
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_req_may_be_done_not_susp(req, m);
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put_ldev(mdev);
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break;
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case READ_COMPLETED_WITH_ERROR:
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drbd_set_out_of_sync(mdev, req->i.sector, req->i.size);
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req->rq_state |= RQ_LOCAL_COMPLETED;
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req->rq_state &= ~RQ_LOCAL_PENDING;
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D_ASSERT(!(req->rq_state & RQ_NET_MASK));
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__drbd_chk_io_error(mdev, false);
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put_ldev(mdev);
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/* no point in retrying if there is no good remote data,
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* or we have no connection. */
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if (mdev->state.pdsk != D_UP_TO_DATE) {
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_req_may_be_done_not_susp(req, m);
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break;
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}
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/* _req_mod(req,TO_BE_SENT); oops, recursion... */
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req->rq_state |= RQ_NET_PENDING;
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inc_ap_pending(mdev);
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/* fall through: _req_mod(req,QUEUE_FOR_NET_READ); */
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case QUEUE_FOR_NET_READ:
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/* READ or READA, and
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* no local disk,
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* or target area marked as invalid,
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* or just got an io-error. */
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/* from drbd_make_request_common
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* or from bio_endio during read io-error recovery */
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/* so we can verify the handle in the answer packet
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* corresponding hlist_del is in _req_may_be_done() */
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drbd_insert_interval(&mdev->read_requests, &req->i);
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set_bit(UNPLUG_REMOTE, &mdev->flags);
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D_ASSERT(req->rq_state & RQ_NET_PENDING);
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req->rq_state |= RQ_NET_QUEUED;
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req->w.cb = (req->rq_state & RQ_LOCAL_MASK)
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? w_read_retry_remote
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: w_send_read_req;
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drbd_queue_work(&mdev->tconn->data.work, &req->w);
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break;
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case QUEUE_FOR_NET_WRITE:
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/* assert something? */
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/* from drbd_make_request_common only */
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/* corresponding hlist_del is in _req_may_be_done() */
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drbd_insert_interval(&mdev->write_requests, &req->i);
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/* NOTE
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* In case the req ended up on the transfer log before being
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* queued on the worker, it could lead to this request being
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* missed during cleanup after connection loss.
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* So we have to do both operations here,
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* within the same lock that protects the transfer log.
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*
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* _req_add_to_epoch(req); this has to be after the
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* _maybe_start_new_epoch(req); which happened in
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* drbd_make_request_common, because we now may set the bit
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* again ourselves to close the current epoch.
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*
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* Add req to the (now) current epoch (barrier). */
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/* otherwise we may lose an unplug, which may cause some remote
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* io-scheduler timeout to expire, increasing maximum latency,
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* hurting performance. */
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set_bit(UNPLUG_REMOTE, &mdev->flags);
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/* see drbd_make_request_common,
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* just after it grabs the req_lock */
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D_ASSERT(test_bit(CREATE_BARRIER, &mdev->flags) == 0);
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req->epoch = mdev->tconn->newest_tle->br_number;
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/* increment size of current epoch */
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mdev->tconn->newest_tle->n_writes++;
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|
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/* queue work item to send data */
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D_ASSERT(req->rq_state & RQ_NET_PENDING);
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req->rq_state |= RQ_NET_QUEUED;
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req->w.cb = w_send_dblock;
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drbd_queue_work(&mdev->tconn->data.work, &req->w);
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/* close the epoch, in case it outgrew the limit */
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if (mdev->tconn->newest_tle->n_writes >= mdev->tconn->net_conf->max_epoch_size)
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queue_barrier(mdev);
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break;
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case QUEUE_FOR_SEND_OOS:
|
|
req->rq_state |= RQ_NET_QUEUED;
|
|
req->w.cb = w_send_oos;
|
|
drbd_queue_work(&mdev->tconn->data.work, &req->w);
|
|
break;
|
|
|
|
case OOS_HANDED_TO_NETWORK:
|
|
/* actually the same */
|
|
case SEND_CANCELED:
|
|
/* treat it the same */
|
|
case SEND_FAILED:
|
|
/* real cleanup will be done from tl_clear. just update flags
|
|
* so it is no longer marked as on the worker queue */
|
|
req->rq_state &= ~RQ_NET_QUEUED;
|
|
/* if we did it right, tl_clear should be scheduled only after
|
|
* this, so this should not be necessary! */
|
|
_req_may_be_done_not_susp(req, m);
|
|
break;
|
|
|
|
case HANDED_OVER_TO_NETWORK:
|
|
/* assert something? */
|
|
if (bio_data_dir(req->master_bio) == WRITE)
|
|
atomic_add(req->i.size >> 9, &mdev->ap_in_flight);
|
|
|
|
if (bio_data_dir(req->master_bio) == WRITE &&
|
|
mdev->tconn->net_conf->wire_protocol == DRBD_PROT_A) {
|
|
/* this is what is dangerous about protocol A:
|
|
* pretend it was successfully written on the peer. */
|
|
if (req->rq_state & RQ_NET_PENDING) {
|
|
dec_ap_pending(mdev);
|
|
req->rq_state &= ~RQ_NET_PENDING;
|
|
req->rq_state |= RQ_NET_OK;
|
|
} /* else: neg-ack was faster... */
|
|
/* it is still not yet RQ_NET_DONE until the
|
|
* corresponding epoch barrier got acked as well,
|
|
* so we know what to dirty on connection loss */
|
|
}
|
|
req->rq_state &= ~RQ_NET_QUEUED;
|
|
req->rq_state |= RQ_NET_SENT;
|
|
/* because _drbd_send_zc_bio could sleep, and may want to
|
|
* dereference the bio even after the "WRITE_ACKED_BY_PEER" and
|
|
* "COMPLETED_OK" events came in, once we return from
|
|
* _drbd_send_zc_bio (drbd_send_dblock), we have to check
|
|
* whether it is done already, and end it. */
|
|
_req_may_be_done_not_susp(req, m);
|
|
break;
|
|
|
|
case READ_RETRY_REMOTE_CANCELED:
|
|
req->rq_state &= ~RQ_NET_QUEUED;
|
|
/* fall through, in case we raced with drbd_disconnect */
|
|
case CONNECTION_LOST_WHILE_PENDING:
|
|
/* transfer log cleanup after connection loss */
|
|
/* assert something? */
|
|
if (req->rq_state & RQ_NET_PENDING)
|
|
dec_ap_pending(mdev);
|
|
req->rq_state &= ~(RQ_NET_OK|RQ_NET_PENDING);
|
|
req->rq_state |= RQ_NET_DONE;
|
|
if (req->rq_state & RQ_NET_SENT && req->rq_state & RQ_WRITE)
|
|
atomic_sub(req->i.size >> 9, &mdev->ap_in_flight);
|
|
|
|
/* if it is still queued, we may not complete it here.
|
|
* it will be canceled soon. */
|
|
if (!(req->rq_state & RQ_NET_QUEUED))
|
|
_req_may_be_done(req, m); /* Allowed while state.susp */
|
|
break;
|
|
|
|
case WRITE_ACKED_BY_PEER_AND_SIS:
|
|
req->rq_state |= RQ_NET_SIS;
|
|
case CONFLICT_DISCARDED_BY_PEER:
|
|
/* for discarded conflicting writes of multiple primaries,
|
|
* there is no need to keep anything in the tl, potential
|
|
* node crashes are covered by the activity log. */
|
|
if (what == CONFLICT_DISCARDED_BY_PEER)
|
|
dev_alert(DEV, "Got DiscardAck packet %llus +%u!"
|
|
" DRBD is not a random data generator!\n",
|
|
(unsigned long long)req->i.sector, req->i.size);
|
|
req->rq_state |= RQ_NET_DONE;
|
|
/* fall through */
|
|
case WRITE_ACKED_BY_PEER:
|
|
/* protocol C; successfully written on peer.
|
|
* Nothing to do here.
|
|
* We want to keep the tl in place for all protocols, to cater
|
|
* for volatile write-back caches on lower level devices.
|
|
*
|
|
* A barrier request is expected to have forced all prior
|
|
* requests onto stable storage, so completion of a barrier
|
|
* request could set NET_DONE right here, and not wait for the
|
|
* P_BARRIER_ACK, but that is an unnecessary optimization. */
|
|
|
|
/* this makes it effectively the same as for: */
|
|
case RECV_ACKED_BY_PEER:
|
|
/* protocol B; pretends to be successfully written on peer.
|
|
* see also notes above in HANDED_OVER_TO_NETWORK about
|
|
* protocol != C */
|
|
req->rq_state |= RQ_NET_OK;
|
|
D_ASSERT(req->rq_state & RQ_NET_PENDING);
|
|
dec_ap_pending(mdev);
|
|
atomic_sub(req->i.size >> 9, &mdev->ap_in_flight);
|
|
req->rq_state &= ~RQ_NET_PENDING;
|
|
_req_may_be_done_not_susp(req, m);
|
|
break;
|
|
|
|
case NEG_ACKED:
|
|
/* assert something? */
|
|
if (req->rq_state & RQ_NET_PENDING) {
|
|
dec_ap_pending(mdev);
|
|
atomic_sub(req->i.size >> 9, &mdev->ap_in_flight);
|
|
}
|
|
req->rq_state &= ~(RQ_NET_OK|RQ_NET_PENDING);
|
|
|
|
req->rq_state |= RQ_NET_DONE;
|
|
_req_may_be_done_not_susp(req, m);
|
|
/* else: done by HANDED_OVER_TO_NETWORK */
|
|
break;
|
|
|
|
case FAIL_FROZEN_DISK_IO:
|
|
if (!(req->rq_state & RQ_LOCAL_COMPLETED))
|
|
break;
|
|
|
|
_req_may_be_done(req, m); /* Allowed while state.susp */
|
|
break;
|
|
|
|
case RESTART_FROZEN_DISK_IO:
|
|
if (!(req->rq_state & RQ_LOCAL_COMPLETED))
|
|
break;
|
|
|
|
req->rq_state &= ~RQ_LOCAL_COMPLETED;
|
|
|
|
rv = MR_READ;
|
|
if (bio_data_dir(req->master_bio) == WRITE)
|
|
rv = MR_WRITE;
|
|
|
|
get_ldev(mdev);
|
|
req->w.cb = w_restart_disk_io;
|
|
drbd_queue_work(&mdev->tconn->data.work, &req->w);
|
|
break;
|
|
|
|
case RESEND:
|
|
/* If RQ_NET_OK is already set, we got a P_WRITE_ACK or P_RECV_ACK
|
|
before the connection loss (B&C only); only P_BARRIER_ACK was missing.
|
|
Trowing them out of the TL here by pretending we got a BARRIER_ACK
|
|
We ensure that the peer was not rebooted */
|
|
if (!(req->rq_state & RQ_NET_OK)) {
|
|
if (req->w.cb) {
|
|
drbd_queue_work(&mdev->tconn->data.work, &req->w);
|
|
rv = req->rq_state & RQ_WRITE ? MR_WRITE : MR_READ;
|
|
}
|
|
break;
|
|
}
|
|
/* else, fall through to BARRIER_ACKED */
|
|
|
|
case BARRIER_ACKED:
|
|
if (!(req->rq_state & RQ_WRITE))
|
|
break;
|
|
|
|
if (req->rq_state & RQ_NET_PENDING) {
|
|
/* barrier came in before all requests have been acked.
|
|
* this is bad, because if the connection is lost now,
|
|
* we won't be able to clean them up... */
|
|
dev_err(DEV, "FIXME (BARRIER_ACKED but pending)\n");
|
|
list_move(&req->tl_requests, &mdev->tconn->out_of_sequence_requests);
|
|
}
|
|
if ((req->rq_state & RQ_NET_MASK) != 0) {
|
|
req->rq_state |= RQ_NET_DONE;
|
|
if (mdev->tconn->net_conf->wire_protocol == DRBD_PROT_A)
|
|
atomic_sub(req->i.size>>9, &mdev->ap_in_flight);
|
|
}
|
|
_req_may_be_done(req, m); /* Allowed while state.susp */
|
|
break;
|
|
|
|
case DATA_RECEIVED:
|
|
D_ASSERT(req->rq_state & RQ_NET_PENDING);
|
|
dec_ap_pending(mdev);
|
|
req->rq_state &= ~RQ_NET_PENDING;
|
|
req->rq_state |= (RQ_NET_OK|RQ_NET_DONE);
|
|
_req_may_be_done_not_susp(req, m);
|
|
break;
|
|
};
|
|
|
|
return rv;
|
|
}
|
|
|
|
/* we may do a local read if:
|
|
* - we are consistent (of course),
|
|
* - or we are generally inconsistent,
|
|
* BUT we are still/already IN SYNC for this area.
|
|
* since size may be bigger than BM_BLOCK_SIZE,
|
|
* we may need to check several bits.
|
|
*/
|
|
static int drbd_may_do_local_read(struct drbd_conf *mdev, sector_t sector, int size)
|
|
{
|
|
unsigned long sbnr, ebnr;
|
|
sector_t esector, nr_sectors;
|
|
|
|
if (mdev->state.disk == D_UP_TO_DATE)
|
|
return 1;
|
|
if (mdev->state.disk >= D_OUTDATED)
|
|
return 0;
|
|
if (mdev->state.disk < D_INCONSISTENT)
|
|
return 0;
|
|
/* state.disk == D_INCONSISTENT We will have a look at the BitMap */
|
|
nr_sectors = drbd_get_capacity(mdev->this_bdev);
|
|
esector = sector + (size >> 9) - 1;
|
|
|
|
D_ASSERT(sector < nr_sectors);
|
|
D_ASSERT(esector < nr_sectors);
|
|
|
|
sbnr = BM_SECT_TO_BIT(sector);
|
|
ebnr = BM_SECT_TO_BIT(esector);
|
|
|
|
return 0 == drbd_bm_count_bits(mdev, sbnr, ebnr);
|
|
}
|
|
|
|
/*
|
|
* complete_conflicting_writes - wait for any conflicting write requests
|
|
*
|
|
* The write_requests tree contains all active write requests which we
|
|
* currently know about. Wait for any requests to complete which conflict with
|
|
* the new one.
|
|
*/
|
|
static int complete_conflicting_writes(struct drbd_conf *mdev,
|
|
sector_t sector, int size)
|
|
{
|
|
for(;;) {
|
|
DEFINE_WAIT(wait);
|
|
struct drbd_interval *i;
|
|
|
|
i = drbd_find_overlap(&mdev->write_requests, sector, size);
|
|
if (!i)
|
|
return 0;
|
|
i->waiting = true;
|
|
prepare_to_wait(&mdev->misc_wait, &wait, TASK_INTERRUPTIBLE);
|
|
spin_unlock_irq(&mdev->tconn->req_lock);
|
|
schedule();
|
|
finish_wait(&mdev->misc_wait, &wait);
|
|
spin_lock_irq(&mdev->tconn->req_lock);
|
|
if (signal_pending(current))
|
|
return -ERESTARTSYS;
|
|
}
|
|
}
|
|
|
|
static int drbd_make_request_common(struct drbd_conf *mdev, struct bio *bio, unsigned long start_time)
|
|
{
|
|
const int rw = bio_rw(bio);
|
|
const int size = bio->bi_size;
|
|
const sector_t sector = bio->bi_sector;
|
|
struct drbd_tl_epoch *b = NULL;
|
|
struct drbd_request *req;
|
|
int local, remote, send_oos = 0;
|
|
int err;
|
|
int ret = 0;
|
|
|
|
/* allocate outside of all locks; */
|
|
req = drbd_req_new(mdev, bio);
|
|
if (!req) {
|
|
dec_ap_bio(mdev);
|
|
/* only pass the error to the upper layers.
|
|
* if user cannot handle io errors, that's not our business. */
|
|
dev_err(DEV, "could not kmalloc() req\n");
|
|
bio_endio(bio, -ENOMEM);
|
|
return 0;
|
|
}
|
|
req->start_time = start_time;
|
|
|
|
local = get_ldev(mdev);
|
|
if (!local) {
|
|
bio_put(req->private_bio); /* or we get a bio leak */
|
|
req->private_bio = NULL;
|
|
}
|
|
if (rw == WRITE) {
|
|
remote = 1;
|
|
} else {
|
|
/* READ || READA */
|
|
if (local) {
|
|
if (!drbd_may_do_local_read(mdev, sector, size)) {
|
|
/* we could kick the syncer to
|
|
* sync this extent asap, wait for
|
|
* it, then continue locally.
|
|
* Or just issue the request remotely.
|
|
*/
|
|
local = 0;
|
|
bio_put(req->private_bio);
|
|
req->private_bio = NULL;
|
|
put_ldev(mdev);
|
|
}
|
|
}
|
|
remote = !local && mdev->state.pdsk >= D_UP_TO_DATE;
|
|
}
|
|
|
|
/* If we have a disk, but a READA request is mapped to remote,
|
|
* we are R_PRIMARY, D_INCONSISTENT, SyncTarget.
|
|
* Just fail that READA request right here.
|
|
*
|
|
* THINK: maybe fail all READA when not local?
|
|
* or make this configurable...
|
|
* if network is slow, READA won't do any good.
|
|
*/
|
|
if (rw == READA && mdev->state.disk >= D_INCONSISTENT && !local) {
|
|
err = -EWOULDBLOCK;
|
|
goto fail_and_free_req;
|
|
}
|
|
|
|
/* For WRITES going to the local disk, grab a reference on the target
|
|
* extent. This waits for any resync activity in the corresponding
|
|
* resync extent to finish, and, if necessary, pulls in the target
|
|
* extent into the activity log, which involves further disk io because
|
|
* of transactional on-disk meta data updates. */
|
|
if (rw == WRITE && local && !test_bit(AL_SUSPENDED, &mdev->flags)) {
|
|
req->rq_state |= RQ_IN_ACT_LOG;
|
|
drbd_al_begin_io(mdev, sector);
|
|
}
|
|
|
|
remote = remote && drbd_should_do_remote(mdev->state);
|
|
send_oos = rw == WRITE && drbd_should_send_oos(mdev->state);
|
|
D_ASSERT(!(remote && send_oos));
|
|
|
|
if (!(local || remote) && !is_susp(mdev->state)) {
|
|
if (__ratelimit(&drbd_ratelimit_state))
|
|
dev_err(DEV, "IO ERROR: neither local nor remote disk\n");
|
|
err = -EIO;
|
|
goto fail_free_complete;
|
|
}
|
|
|
|
/* For WRITE request, we have to make sure that we have an
|
|
* unused_spare_tle, in case we need to start a new epoch.
|
|
* I try to be smart and avoid to pre-allocate always "just in case",
|
|
* but there is a race between testing the bit and pointer outside the
|
|
* spinlock, and grabbing the spinlock.
|
|
* if we lost that race, we retry. */
|
|
if (rw == WRITE && (remote || send_oos) &&
|
|
mdev->tconn->unused_spare_tle == NULL &&
|
|
test_bit(CREATE_BARRIER, &mdev->flags)) {
|
|
allocate_barrier:
|
|
b = kmalloc(sizeof(struct drbd_tl_epoch), GFP_NOIO);
|
|
if (!b) {
|
|
dev_err(DEV, "Failed to alloc barrier.\n");
|
|
err = -ENOMEM;
|
|
goto fail_free_complete;
|
|
}
|
|
}
|
|
|
|
/* GOOD, everything prepared, grab the spin_lock */
|
|
spin_lock_irq(&mdev->tconn->req_lock);
|
|
|
|
if (rw == WRITE) {
|
|
err = complete_conflicting_writes(mdev, sector, size);
|
|
if (err) {
|
|
spin_unlock_irq(&mdev->tconn->req_lock);
|
|
goto fail_free_complete;
|
|
}
|
|
}
|
|
|
|
if (is_susp(mdev->state)) {
|
|
/* If we got suspended, use the retry mechanism of
|
|
generic_make_request() to restart processing of this
|
|
bio. In the next call to drbd_make_request
|
|
we sleep in inc_ap_bio() */
|
|
ret = 1;
|
|
spin_unlock_irq(&mdev->tconn->req_lock);
|
|
goto fail_free_complete;
|
|
}
|
|
|
|
if (remote || send_oos) {
|
|
remote = drbd_should_do_remote(mdev->state);
|
|
send_oos = rw == WRITE && drbd_should_send_oos(mdev->state);
|
|
D_ASSERT(!(remote && send_oos));
|
|
|
|
if (!(remote || send_oos))
|
|
dev_warn(DEV, "lost connection while grabbing the req_lock!\n");
|
|
if (!(local || remote)) {
|
|
dev_err(DEV, "IO ERROR: neither local nor remote disk\n");
|
|
spin_unlock_irq(&mdev->tconn->req_lock);
|
|
err = -EIO;
|
|
goto fail_free_complete;
|
|
}
|
|
}
|
|
|
|
if (b && mdev->tconn->unused_spare_tle == NULL) {
|
|
mdev->tconn->unused_spare_tle = b;
|
|
b = NULL;
|
|
}
|
|
if (rw == WRITE && (remote || send_oos) &&
|
|
mdev->tconn->unused_spare_tle == NULL &&
|
|
test_bit(CREATE_BARRIER, &mdev->flags)) {
|
|
/* someone closed the current epoch
|
|
* while we were grabbing the spinlock */
|
|
spin_unlock_irq(&mdev->tconn->req_lock);
|
|
goto allocate_barrier;
|
|
}
|
|
|
|
|
|
/* Update disk stats */
|
|
_drbd_start_io_acct(mdev, req, bio);
|
|
|
|
/* _maybe_start_new_epoch(mdev);
|
|
* If we need to generate a write barrier packet, we have to add the
|
|
* new epoch (barrier) object, and queue the barrier packet for sending,
|
|
* and queue the req's data after it _within the same lock_, otherwise
|
|
* we have race conditions were the reorder domains could be mixed up.
|
|
*
|
|
* Even read requests may start a new epoch and queue the corresponding
|
|
* barrier packet. To get the write ordering right, we only have to
|
|
* make sure that, if this is a write request and it triggered a
|
|
* barrier packet, this request is queued within the same spinlock. */
|
|
if ((remote || send_oos) && mdev->tconn->unused_spare_tle &&
|
|
test_and_clear_bit(CREATE_BARRIER, &mdev->flags)) {
|
|
_tl_add_barrier(mdev, mdev->tconn->unused_spare_tle);
|
|
mdev->tconn->unused_spare_tle = NULL;
|
|
} else {
|
|
D_ASSERT(!(remote && rw == WRITE &&
|
|
test_bit(CREATE_BARRIER, &mdev->flags)));
|
|
}
|
|
|
|
/* NOTE
|
|
* Actually, 'local' may be wrong here already, since we may have failed
|
|
* to write to the meta data, and may become wrong anytime because of
|
|
* local io-error for some other request, which would lead to us
|
|
* "detaching" the local disk.
|
|
*
|
|
* 'remote' may become wrong any time because the network could fail.
|
|
*
|
|
* This is a harmless race condition, though, since it is handled
|
|
* correctly at the appropriate places; so it just defers the failure
|
|
* of the respective operation.
|
|
*/
|
|
|
|
/* mark them early for readability.
|
|
* this just sets some state flags. */
|
|
if (remote)
|
|
_req_mod(req, TO_BE_SENT);
|
|
if (local)
|
|
_req_mod(req, TO_BE_SUBMITTED);
|
|
|
|
list_add_tail(&req->tl_requests, &mdev->tconn->newest_tle->requests);
|
|
|
|
/* NOTE remote first: to get the concurrent write detection right,
|
|
* we must register the request before start of local IO. */
|
|
if (remote) {
|
|
/* either WRITE and C_CONNECTED,
|
|
* or READ, and no local disk,
|
|
* or READ, but not in sync.
|
|
*/
|
|
_req_mod(req, (rw == WRITE)
|
|
? QUEUE_FOR_NET_WRITE
|
|
: QUEUE_FOR_NET_READ);
|
|
}
|
|
if (send_oos && drbd_set_out_of_sync(mdev, sector, size))
|
|
_req_mod(req, QUEUE_FOR_SEND_OOS);
|
|
|
|
if (remote &&
|
|
mdev->tconn->net_conf->on_congestion != OC_BLOCK && mdev->tconn->agreed_pro_version >= 96) {
|
|
int congested = 0;
|
|
|
|
if (mdev->tconn->net_conf->cong_fill &&
|
|
atomic_read(&mdev->ap_in_flight) >= mdev->tconn->net_conf->cong_fill) {
|
|
dev_info(DEV, "Congestion-fill threshold reached\n");
|
|
congested = 1;
|
|
}
|
|
|
|
if (mdev->act_log->used >= mdev->tconn->net_conf->cong_extents) {
|
|
dev_info(DEV, "Congestion-extents threshold reached\n");
|
|
congested = 1;
|
|
}
|
|
|
|
if (congested) {
|
|
queue_barrier(mdev); /* last barrier, after mirrored writes */
|
|
|
|
if (mdev->tconn->net_conf->on_congestion == OC_PULL_AHEAD)
|
|
_drbd_set_state(_NS(mdev, conn, C_AHEAD), 0, NULL);
|
|
else /*mdev->tconn->net_conf->on_congestion == OC_DISCONNECT */
|
|
_drbd_set_state(_NS(mdev, conn, C_DISCONNECTING), 0, NULL);
|
|
}
|
|
}
|
|
|
|
spin_unlock_irq(&mdev->tconn->req_lock);
|
|
kfree(b); /* if someone else has beaten us to it... */
|
|
|
|
if (local) {
|
|
req->private_bio->bi_bdev = mdev->ldev->backing_bdev;
|
|
|
|
/* State may have changed since we grabbed our reference on the
|
|
* mdev->ldev member. Double check, and short-circuit to endio.
|
|
* In case the last activity log transaction failed to get on
|
|
* stable storage, and this is a WRITE, we may not even submit
|
|
* this bio. */
|
|
if (get_ldev(mdev)) {
|
|
if (drbd_insert_fault(mdev, rw == WRITE ? DRBD_FAULT_DT_WR
|
|
: rw == READ ? DRBD_FAULT_DT_RD
|
|
: DRBD_FAULT_DT_RA))
|
|
bio_endio(req->private_bio, -EIO);
|
|
else
|
|
generic_make_request(req->private_bio);
|
|
put_ldev(mdev);
|
|
} else
|
|
bio_endio(req->private_bio, -EIO);
|
|
}
|
|
|
|
return 0;
|
|
|
|
fail_free_complete:
|
|
if (req->rq_state & RQ_IN_ACT_LOG)
|
|
drbd_al_complete_io(mdev, sector);
|
|
fail_and_free_req:
|
|
if (local) {
|
|
bio_put(req->private_bio);
|
|
req->private_bio = NULL;
|
|
put_ldev(mdev);
|
|
}
|
|
if (!ret)
|
|
bio_endio(bio, err);
|
|
|
|
drbd_req_free(req);
|
|
dec_ap_bio(mdev);
|
|
kfree(b);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* helper function for drbd_make_request
|
|
* if we can determine just by the mdev (state) that this request will fail,
|
|
* return 1
|
|
* otherwise return 0
|
|
*/
|
|
static int drbd_fail_request_early(struct drbd_conf *mdev, int is_write)
|
|
{
|
|
if (mdev->state.role != R_PRIMARY &&
|
|
(!allow_oos || is_write)) {
|
|
if (__ratelimit(&drbd_ratelimit_state)) {
|
|
dev_err(DEV, "Process %s[%u] tried to %s; "
|
|
"since we are not in Primary state, "
|
|
"we cannot allow this\n",
|
|
current->comm, current->pid,
|
|
is_write ? "WRITE" : "READ");
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int drbd_make_request(struct request_queue *q, struct bio *bio)
|
|
{
|
|
unsigned int s_enr, e_enr;
|
|
struct drbd_conf *mdev = (struct drbd_conf *) q->queuedata;
|
|
unsigned long start_time;
|
|
|
|
if (drbd_fail_request_early(mdev, bio_data_dir(bio) & WRITE)) {
|
|
bio_endio(bio, -EPERM);
|
|
return 0;
|
|
}
|
|
|
|
start_time = jiffies;
|
|
|
|
/*
|
|
* what we "blindly" assume:
|
|
*/
|
|
D_ASSERT(bio->bi_size > 0);
|
|
D_ASSERT((bio->bi_size & 0x1ff) == 0);
|
|
D_ASSERT(bio->bi_idx == 0);
|
|
|
|
/* to make some things easier, force alignment of requests within the
|
|
* granularity of our hash tables */
|
|
s_enr = bio->bi_sector >> HT_SHIFT;
|
|
e_enr = (bio->bi_sector+(bio->bi_size>>9)-1) >> HT_SHIFT;
|
|
|
|
if (likely(s_enr == e_enr)) {
|
|
inc_ap_bio(mdev, 1);
|
|
return drbd_make_request_common(mdev, bio, start_time);
|
|
}
|
|
|
|
/* can this bio be split generically?
|
|
* Maybe add our own split-arbitrary-bios function. */
|
|
if (bio->bi_vcnt != 1 || bio->bi_idx != 0 || bio->bi_size > DRBD_MAX_BIO_SIZE) {
|
|
/* rather error out here than BUG in bio_split */
|
|
dev_err(DEV, "bio would need to, but cannot, be split: "
|
|
"(vcnt=%u,idx=%u,size=%u,sector=%llu)\n",
|
|
bio->bi_vcnt, bio->bi_idx, bio->bi_size,
|
|
(unsigned long long)bio->bi_sector);
|
|
bio_endio(bio, -EINVAL);
|
|
} else {
|
|
/* This bio crosses some boundary, so we have to split it. */
|
|
struct bio_pair *bp;
|
|
/* works for the "do not cross hash slot boundaries" case
|
|
* e.g. sector 262269, size 4096
|
|
* s_enr = 262269 >> 6 = 4097
|
|
* e_enr = (262269+8-1) >> 6 = 4098
|
|
* HT_SHIFT = 6
|
|
* sps = 64, mask = 63
|
|
* first_sectors = 64 - (262269 & 63) = 3
|
|
*/
|
|
const sector_t sect = bio->bi_sector;
|
|
const int sps = 1 << HT_SHIFT; /* sectors per slot */
|
|
const int mask = sps - 1;
|
|
const sector_t first_sectors = sps - (sect & mask);
|
|
bp = bio_split(bio, first_sectors);
|
|
|
|
/* we need to get a "reference count" (ap_bio_cnt)
|
|
* to avoid races with the disconnect/reconnect/suspend code.
|
|
* In case we need to split the bio here, we need to get three references
|
|
* atomically, otherwise we might deadlock when trying to submit the
|
|
* second one! */
|
|
inc_ap_bio(mdev, 3);
|
|
|
|
D_ASSERT(e_enr == s_enr + 1);
|
|
|
|
while (drbd_make_request_common(mdev, &bp->bio1, start_time))
|
|
inc_ap_bio(mdev, 1);
|
|
|
|
while (drbd_make_request_common(mdev, &bp->bio2, start_time))
|
|
inc_ap_bio(mdev, 1);
|
|
|
|
dec_ap_bio(mdev);
|
|
|
|
bio_pair_release(bp);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* This is called by bio_add_page(). With this function we reduce
|
|
* the number of BIOs that span over multiple DRBD_MAX_BIO_SIZEs
|
|
* units (was AL_EXTENTs).
|
|
*
|
|
* we do the calculation within the lower 32bit of the byte offsets,
|
|
* since we don't care for actual offset, but only check whether it
|
|
* would cross "activity log extent" boundaries.
|
|
*
|
|
* As long as the BIO is empty we have to allow at least one bvec,
|
|
* regardless of size and offset. so the resulting bio may still
|
|
* cross extent boundaries. those are dealt with (bio_split) in
|
|
* drbd_make_request.
|
|
*/
|
|
int drbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct bio_vec *bvec)
|
|
{
|
|
struct drbd_conf *mdev = (struct drbd_conf *) q->queuedata;
|
|
unsigned int bio_offset =
|
|
(unsigned int)bvm->bi_sector << 9; /* 32 bit */
|
|
unsigned int bio_size = bvm->bi_size;
|
|
int limit, backing_limit;
|
|
|
|
limit = DRBD_MAX_BIO_SIZE
|
|
- ((bio_offset & (DRBD_MAX_BIO_SIZE-1)) + bio_size);
|
|
if (limit < 0)
|
|
limit = 0;
|
|
if (bio_size == 0) {
|
|
if (limit <= bvec->bv_len)
|
|
limit = bvec->bv_len;
|
|
} else if (limit && get_ldev(mdev)) {
|
|
struct request_queue * const b =
|
|
mdev->ldev->backing_bdev->bd_disk->queue;
|
|
if (b->merge_bvec_fn) {
|
|
backing_limit = b->merge_bvec_fn(b, bvm, bvec);
|
|
limit = min(limit, backing_limit);
|
|
}
|
|
put_ldev(mdev);
|
|
}
|
|
return limit;
|
|
}
|
|
|
|
void request_timer_fn(unsigned long data)
|
|
{
|
|
struct drbd_conf *mdev = (struct drbd_conf *) data;
|
|
struct drbd_request *req; /* oldest request */
|
|
struct list_head *le;
|
|
unsigned long et = 0; /* effective timeout = ko_count * timeout */
|
|
|
|
if (get_net_conf(mdev->tconn)) {
|
|
et = mdev->tconn->net_conf->timeout*HZ/10 * mdev->tconn->net_conf->ko_count;
|
|
put_net_conf(mdev->tconn);
|
|
}
|
|
if (!et || mdev->state.conn < C_WF_REPORT_PARAMS)
|
|
return; /* Recurring timer stopped */
|
|
|
|
spin_lock_irq(&mdev->tconn->req_lock);
|
|
le = &mdev->tconn->oldest_tle->requests;
|
|
if (list_empty(le)) {
|
|
spin_unlock_irq(&mdev->tconn->req_lock);
|
|
mod_timer(&mdev->request_timer, jiffies + et);
|
|
return;
|
|
}
|
|
|
|
le = le->prev;
|
|
req = list_entry(le, struct drbd_request, tl_requests);
|
|
if (time_is_before_eq_jiffies(req->start_time + et)) {
|
|
if (req->rq_state & RQ_NET_PENDING) {
|
|
dev_warn(DEV, "Remote failed to finish a request within ko-count * timeout\n");
|
|
_drbd_set_state(_NS(mdev, conn, C_TIMEOUT), CS_VERBOSE, NULL);
|
|
} else {
|
|
dev_warn(DEV, "Local backing block device frozen?\n");
|
|
mod_timer(&mdev->request_timer, jiffies + et);
|
|
}
|
|
} else {
|
|
mod_timer(&mdev->request_timer, req->start_time + et);
|
|
}
|
|
|
|
spin_unlock_irq(&mdev->tconn->req_lock);
|
|
}
|