1402 строки
41 KiB
C
1402 строки
41 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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static bool drbd_may_do_local_read(struct drbd_conf *mdev, sector_t sector, int size);
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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)
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{
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const int rw = bio_data_dir(req->master_bio);
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int cpu;
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cpu = part_stat_lock();
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part_round_stats(cpu, &mdev->vdisk->part0);
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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], req->i.size >> 9);
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(void) cpu; /* The macro invocations above want the cpu argument, I do not like
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the compiler warning about cpu only assigned but never used... */
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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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/* one reference to be put by __drbd_make_request */
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atomic_set(&req->completion_ref, 1);
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/* one kref as long as completion_ref > 0 */
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kref_init(&req->kref);
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return req;
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}
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void drbd_req_destroy(struct kref *kref)
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{
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struct drbd_request *req = container_of(kref, struct drbd_request, kref);
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struct drbd_conf *mdev = req->w.mdev;
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const unsigned s = req->rq_state;
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if ((req->master_bio && !(s & RQ_POSTPONED)) ||
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atomic_read(&req->completion_ref) ||
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(s & RQ_LOCAL_PENDING) ||
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((s & RQ_NET_MASK) && !(s & RQ_NET_DONE))) {
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dev_err(DEV, "drbd_req_destroy: Logic BUG rq_state = 0x%x, completion_ref = %d\n",
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s, atomic_read(&req->completion_ref));
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return;
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}
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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_init(&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 (s & RQ_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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/* There is a special case:
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* we may notice late that IO was suspended,
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* and postpone, or schedule for retry, a write,
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* before it even was submitted or sent.
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* In that case we do not want to touch the bitmap at all.
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*/
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if ((s & (RQ_POSTPONED|RQ_LOCAL_MASK|RQ_NET_MASK)) != RQ_POSTPONED) {
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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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}
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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_request_endio.
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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_IN_ACT_LOG) {
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if (get_ldev_if_state(mdev, D_FAILED)) {
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drbd_al_complete_io(mdev, &req->i);
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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, %u), "
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"but my Disk seems to have failed :(\n",
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(unsigned long long) req->i.sector, req->i.size);
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}
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}
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}
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mempool_free(req, drbd_request_mempool);
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}
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static void wake_all_senders(struct drbd_tconn *tconn) {
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wake_up(&tconn->sender_work.q_wait);
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}
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/* must hold resource->req_lock */
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void start_new_tl_epoch(struct drbd_tconn *tconn)
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{
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/* no point closing an epoch, if it is empty, anyways. */
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if (tconn->current_tle_writes == 0)
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return;
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tconn->current_tle_writes = 0;
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atomic_inc(&tconn->current_tle_nr);
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wake_all_senders(tconn);
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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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static
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void drbd_req_complete(struct drbd_request *req, struct bio_and_error *m)
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{
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const unsigned s = req->rq_state;
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struct drbd_conf *mdev = req->w.mdev;
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int rw;
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int error, ok;
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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_LOCAL_PENDING && !(s & RQ_LOCAL_ABORTED)) ||
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(s & RQ_NET_QUEUED) || (s & RQ_NET_PENDING) ||
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(s & RQ_COMPLETION_SUSP)) {
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dev_err(DEV, "drbd_req_complete: Logic BUG rq_state = 0x%x\n", s);
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return;
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}
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if (!req->master_bio) {
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dev_err(DEV, "drbd_req_complete: Logic BUG, master_bio == NULL!\n");
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return;
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}
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rw = bio_rw(req->master_bio);
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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_request_endio.
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*/
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ok = (s & RQ_LOCAL_OK) || (s & RQ_NET_OK);
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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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}
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/* Before we can signal completion to the upper layers,
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* we may need to close the current transfer log epoch.
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* We are within the request lock, so we can simply compare
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* the request epoch number with the current transfer log
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* epoch number. If they match, increase the current_tle_nr,
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* and reset the transfer log epoch write_cnt.
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*/
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if (rw == WRITE &&
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req->epoch == atomic_read(&mdev->tconn->current_tle_nr))
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start_new_tl_epoch(mdev->tconn);
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/* Update disk stats */
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_drbd_end_io_acct(mdev, req);
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/* If READ failed,
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* have it be pushed back to the retry work queue,
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* so it will re-enter __drbd_make_request(),
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* and be re-assigned to a suitable local or remote path,
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* or failed if we do not have access to good data anymore.
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*
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* Unless it was failed early by __drbd_make_request(),
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* because no path was available, in which case
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* it was not even added to the transfer_log.
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*
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* READA may fail, and will not be retried.
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*
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* WRITE should have used all available paths already.
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*/
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if (!ok && rw == READ && !list_empty(&req->tl_requests))
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req->rq_state |= RQ_POSTPONED;
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if (!(req->rq_state & RQ_POSTPONED)) {
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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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}
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static int drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put)
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{
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struct drbd_conf *mdev = req->w.mdev;
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D_ASSERT(m || (req->rq_state & RQ_POSTPONED));
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if (!atomic_sub_and_test(put, &req->completion_ref))
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return 0;
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drbd_req_complete(req, m);
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if (req->rq_state & RQ_POSTPONED) {
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/* don't destroy the req object just yet,
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* but queue it for retry */
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drbd_restart_request(req);
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return 0;
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}
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return 1;
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}
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/* I'd like this to be the only place that manipulates
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* req->completion_ref and req->kref. */
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static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m,
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int clear, int set)
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{
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struct drbd_conf *mdev = req->w.mdev;
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unsigned s = req->rq_state;
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int c_put = 0;
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int k_put = 0;
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if (drbd_suspended(mdev) && !((s | clear) & RQ_COMPLETION_SUSP))
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set |= RQ_COMPLETION_SUSP;
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/* apply */
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req->rq_state &= ~clear;
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req->rq_state |= set;
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/* no change? */
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if (req->rq_state == s)
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return;
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/* intent: get references */
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if (!(s & RQ_LOCAL_PENDING) && (set & RQ_LOCAL_PENDING))
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atomic_inc(&req->completion_ref);
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if (!(s & RQ_NET_PENDING) && (set & RQ_NET_PENDING)) {
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inc_ap_pending(mdev);
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atomic_inc(&req->completion_ref);
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}
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if (!(s & RQ_NET_QUEUED) && (set & RQ_NET_QUEUED))
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atomic_inc(&req->completion_ref);
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if (!(s & RQ_EXP_BARR_ACK) && (set & RQ_EXP_BARR_ACK))
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kref_get(&req->kref); /* wait for the DONE */
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if (!(s & RQ_NET_SENT) && (set & RQ_NET_SENT))
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atomic_add(req->i.size >> 9, &mdev->ap_in_flight);
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if (!(s & RQ_COMPLETION_SUSP) && (set & RQ_COMPLETION_SUSP))
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atomic_inc(&req->completion_ref);
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/* progress: put references */
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if ((s & RQ_COMPLETION_SUSP) && (clear & RQ_COMPLETION_SUSP))
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++c_put;
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if (!(s & RQ_LOCAL_ABORTED) && (set & RQ_LOCAL_ABORTED)) {
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D_ASSERT(req->rq_state & RQ_LOCAL_PENDING);
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/* local completion may still come in later,
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* we need to keep the req object around. */
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kref_get(&req->kref);
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++c_put;
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}
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if ((s & RQ_LOCAL_PENDING) && (clear & RQ_LOCAL_PENDING)) {
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if (req->rq_state & RQ_LOCAL_ABORTED)
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++k_put;
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else
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++c_put;
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}
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if ((s & RQ_NET_PENDING) && (clear & RQ_NET_PENDING)) {
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dec_ap_pending(mdev);
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++c_put;
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}
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if ((s & RQ_NET_QUEUED) && (clear & RQ_NET_QUEUED))
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++c_put;
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if ((s & RQ_EXP_BARR_ACK) && !(s & RQ_NET_DONE) && (set & RQ_NET_DONE)) {
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if (req->rq_state & RQ_NET_SENT)
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atomic_sub(req->i.size >> 9, &mdev->ap_in_flight);
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++k_put;
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}
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/* potentially complete and destroy */
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if (k_put || c_put) {
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/* Completion does it's own kref_put. If we are going to
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* kref_sub below, we need req to be still around then. */
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int at_least = k_put + !!c_put;
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int refcount = atomic_read(&req->kref.refcount);
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if (refcount < at_least)
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dev_err(DEV,
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"mod_rq_state: Logic BUG: %x -> %x: refcount = %d, should be >= %d\n",
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s, req->rq_state, refcount, at_least);
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}
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/* If we made progress, retry conflicting peer requests, if any. */
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if (req->i.waiting)
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wake_up(&mdev->misc_wait);
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if (c_put)
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k_put += drbd_req_put_completion_ref(req, m, c_put);
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if (k_put)
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kref_sub(&req->kref, k_put, drbd_req_destroy);
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}
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static void drbd_report_io_error(struct drbd_conf *mdev, struct drbd_request *req)
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{
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char b[BDEVNAME_SIZE];
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if (!__ratelimit(&drbd_ratelimit_state))
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return;
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dev_warn(DEV, "local %s IO error sector %llu+%u on %s\n",
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(req->rq_state & RQ_WRITE) ? "WRITE" : "READ",
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(unsigned long long)req->i.sector,
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req->i.size >> 9,
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bdevname(mdev->ldev->backing_bdev, b));
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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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struct net_conf *nc;
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int p, rv = 0;
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if (m)
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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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*/
|
|
|
|
case TO_BE_SENT: /* via network */
|
|
/* reached via __drbd_make_request
|
|
* and from w_read_retry_remote */
|
|
D_ASSERT(!(req->rq_state & RQ_NET_MASK));
|
|
rcu_read_lock();
|
|
nc = rcu_dereference(mdev->tconn->net_conf);
|
|
p = nc->wire_protocol;
|
|
rcu_read_unlock();
|
|
req->rq_state |=
|
|
p == DRBD_PROT_C ? RQ_EXP_WRITE_ACK :
|
|
p == DRBD_PROT_B ? RQ_EXP_RECEIVE_ACK : 0;
|
|
mod_rq_state(req, m, 0, RQ_NET_PENDING);
|
|
break;
|
|
|
|
case TO_BE_SUBMITTED: /* locally */
|
|
/* reached via __drbd_make_request */
|
|
D_ASSERT(!(req->rq_state & RQ_LOCAL_MASK));
|
|
mod_rq_state(req, m, 0, RQ_LOCAL_PENDING);
|
|
break;
|
|
|
|
case COMPLETED_OK:
|
|
if (req->rq_state & RQ_WRITE)
|
|
mdev->writ_cnt += req->i.size >> 9;
|
|
else
|
|
mdev->read_cnt += req->i.size >> 9;
|
|
|
|
mod_rq_state(req, m, RQ_LOCAL_PENDING,
|
|
RQ_LOCAL_COMPLETED|RQ_LOCAL_OK);
|
|
break;
|
|
|
|
case ABORT_DISK_IO:
|
|
mod_rq_state(req, m, 0, RQ_LOCAL_ABORTED);
|
|
break;
|
|
|
|
case WRITE_COMPLETED_WITH_ERROR:
|
|
drbd_report_io_error(mdev, req);
|
|
__drbd_chk_io_error(mdev, DRBD_WRITE_ERROR);
|
|
mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED);
|
|
break;
|
|
|
|
case READ_COMPLETED_WITH_ERROR:
|
|
drbd_set_out_of_sync(mdev, req->i.sector, req->i.size);
|
|
drbd_report_io_error(mdev, req);
|
|
__drbd_chk_io_error(mdev, DRBD_READ_ERROR);
|
|
/* fall through. */
|
|
case READ_AHEAD_COMPLETED_WITH_ERROR:
|
|
/* it is legal to fail READA, no __drbd_chk_io_error in that case. */
|
|
mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED);
|
|
break;
|
|
|
|
case QUEUE_FOR_NET_READ:
|
|
/* READ or READA, and
|
|
* no local disk,
|
|
* or target area marked as invalid,
|
|
* or just got an io-error. */
|
|
/* from __drbd_make_request
|
|
* or from bio_endio during read io-error recovery */
|
|
|
|
/* So we can verify the handle in the answer packet.
|
|
* Corresponding drbd_remove_request_interval is in
|
|
* drbd_req_complete() */
|
|
D_ASSERT(drbd_interval_empty(&req->i));
|
|
drbd_insert_interval(&mdev->read_requests, &req->i);
|
|
|
|
set_bit(UNPLUG_REMOTE, &mdev->flags);
|
|
|
|
D_ASSERT(req->rq_state & RQ_NET_PENDING);
|
|
D_ASSERT((req->rq_state & RQ_LOCAL_MASK) == 0);
|
|
mod_rq_state(req, m, 0, RQ_NET_QUEUED);
|
|
req->w.cb = w_send_read_req;
|
|
drbd_queue_work(&mdev->tconn->sender_work, &req->w);
|
|
break;
|
|
|
|
case QUEUE_FOR_NET_WRITE:
|
|
/* assert something? */
|
|
/* from __drbd_make_request only */
|
|
|
|
/* Corresponding drbd_remove_request_interval is in
|
|
* drbd_req_complete() */
|
|
D_ASSERT(drbd_interval_empty(&req->i));
|
|
drbd_insert_interval(&mdev->write_requests, &req->i);
|
|
|
|
/* NOTE
|
|
* In case the req ended up on the transfer log before being
|
|
* queued on the worker, it could lead to this request being
|
|
* missed during cleanup after connection loss.
|
|
* So we have to do both operations here,
|
|
* within the same lock that protects the transfer log.
|
|
*
|
|
* _req_add_to_epoch(req); this has to be after the
|
|
* _maybe_start_new_epoch(req); which happened in
|
|
* __drbd_make_request, because we now may set the bit
|
|
* again ourselves to close the current epoch.
|
|
*
|
|
* Add req to the (now) current epoch (barrier). */
|
|
|
|
/* otherwise we may lose an unplug, which may cause some remote
|
|
* io-scheduler timeout to expire, increasing maximum latency,
|
|
* hurting performance. */
|
|
set_bit(UNPLUG_REMOTE, &mdev->flags);
|
|
|
|
/* queue work item to send data */
|
|
D_ASSERT(req->rq_state & RQ_NET_PENDING);
|
|
mod_rq_state(req, m, 0, RQ_NET_QUEUED|RQ_EXP_BARR_ACK);
|
|
req->w.cb = w_send_dblock;
|
|
drbd_queue_work(&mdev->tconn->sender_work, &req->w);
|
|
|
|
/* close the epoch, in case it outgrew the limit */
|
|
rcu_read_lock();
|
|
nc = rcu_dereference(mdev->tconn->net_conf);
|
|
p = nc->max_epoch_size;
|
|
rcu_read_unlock();
|
|
if (mdev->tconn->current_tle_writes >= p)
|
|
start_new_tl_epoch(mdev->tconn);
|
|
|
|
break;
|
|
|
|
case QUEUE_FOR_SEND_OOS:
|
|
mod_rq_state(req, m, 0, RQ_NET_QUEUED);
|
|
req->w.cb = w_send_out_of_sync;
|
|
drbd_queue_work(&mdev->tconn->sender_work, &req->w);
|
|
break;
|
|
|
|
case READ_RETRY_REMOTE_CANCELED:
|
|
case SEND_CANCELED:
|
|
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 */
|
|
mod_rq_state(req, m, RQ_NET_QUEUED, 0);
|
|
break;
|
|
|
|
case HANDED_OVER_TO_NETWORK:
|
|
/* assert something? */
|
|
if (bio_data_dir(req->master_bio) == WRITE &&
|
|
!(req->rq_state & (RQ_EXP_RECEIVE_ACK | RQ_EXP_WRITE_ACK))) {
|
|
/* this is what is dangerous about protocol A:
|
|
* pretend it was successfully written on the peer. */
|
|
if (req->rq_state & RQ_NET_PENDING)
|
|
mod_rq_state(req, m, RQ_NET_PENDING, 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 */
|
|
}
|
|
mod_rq_state(req, m, RQ_NET_QUEUED, RQ_NET_SENT);
|
|
break;
|
|
|
|
case OOS_HANDED_TO_NETWORK:
|
|
/* Was not set PENDING, no longer QUEUED, so is now DONE
|
|
* as far as this connection is concerned. */
|
|
mod_rq_state(req, m, RQ_NET_QUEUED, RQ_NET_DONE);
|
|
break;
|
|
|
|
case CONNECTION_LOST_WHILE_PENDING:
|
|
/* transfer log cleanup after connection loss */
|
|
mod_rq_state(req, m,
|
|
RQ_NET_OK|RQ_NET_PENDING|RQ_COMPLETION_SUSP,
|
|
RQ_NET_DONE);
|
|
break;
|
|
|
|
case CONFLICT_RESOLVED:
|
|
/* for superseded 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 this request had been marked as RQ_POSTPONED before,
|
|
* it will actually not be completed, but "restarted",
|
|
* resubmitted from the retry worker context. */
|
|
D_ASSERT(req->rq_state & RQ_NET_PENDING);
|
|
D_ASSERT(req->rq_state & RQ_EXP_WRITE_ACK);
|
|
mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_DONE|RQ_NET_OK);
|
|
break;
|
|
|
|
case WRITE_ACKED_BY_PEER_AND_SIS:
|
|
req->rq_state |= RQ_NET_SIS;
|
|
case WRITE_ACKED_BY_PEER:
|
|
D_ASSERT(req->rq_state & RQ_EXP_WRITE_ACK);
|
|
/* protocol C; successfully written on peer.
|
|
* Nothing more 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. */
|
|
|
|
goto ack_common;
|
|
case RECV_ACKED_BY_PEER:
|
|
D_ASSERT(req->rq_state & RQ_EXP_RECEIVE_ACK);
|
|
/* protocol B; pretends to be successfully written on peer.
|
|
* see also notes above in HANDED_OVER_TO_NETWORK about
|
|
* protocol != C */
|
|
ack_common:
|
|
D_ASSERT(req->rq_state & RQ_NET_PENDING);
|
|
mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK);
|
|
break;
|
|
|
|
case POSTPONE_WRITE:
|
|
D_ASSERT(req->rq_state & RQ_EXP_WRITE_ACK);
|
|
/* If this node has already detected the write conflict, the
|
|
* worker will be waiting on misc_wait. Wake it up once this
|
|
* request has completed locally.
|
|
*/
|
|
D_ASSERT(req->rq_state & RQ_NET_PENDING);
|
|
req->rq_state |= RQ_POSTPONED;
|
|
if (req->i.waiting)
|
|
wake_up(&mdev->misc_wait);
|
|
/* Do not clear RQ_NET_PENDING. This request will make further
|
|
* progress via restart_conflicting_writes() or
|
|
* fail_postponed_requests(). Hopefully. */
|
|
break;
|
|
|
|
case NEG_ACKED:
|
|
mod_rq_state(req, m, RQ_NET_OK|RQ_NET_PENDING, 0);
|
|
break;
|
|
|
|
case FAIL_FROZEN_DISK_IO:
|
|
if (!(req->rq_state & RQ_LOCAL_COMPLETED))
|
|
break;
|
|
mod_rq_state(req, m, RQ_COMPLETION_SUSP, 0);
|
|
break;
|
|
|
|
case RESTART_FROZEN_DISK_IO:
|
|
if (!(req->rq_state & RQ_LOCAL_COMPLETED))
|
|
break;
|
|
|
|
mod_rq_state(req, m,
|
|
RQ_COMPLETION_SUSP|RQ_LOCAL_COMPLETED,
|
|
RQ_LOCAL_PENDING);
|
|
|
|
rv = MR_READ;
|
|
if (bio_data_dir(req->master_bio) == WRITE)
|
|
rv = MR_WRITE;
|
|
|
|
get_ldev(mdev); /* always succeeds in this call path */
|
|
req->w.cb = w_restart_disk_io;
|
|
drbd_queue_work(&mdev->tconn->sender_work, &req->w);
|
|
break;
|
|
|
|
case RESEND:
|
|
/* Simply complete (local only) READs. */
|
|
if (!(req->rq_state & RQ_WRITE) && !req->w.cb) {
|
|
mod_rq_state(req, m, RQ_COMPLETION_SUSP, 0);
|
|
break;
|
|
}
|
|
|
|
/* 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
|
|
(or the local completion?) was missing when we suspended.
|
|
Throwing them out of the TL here by pretending we got a BARRIER_ACK.
|
|
During connection handshake, we ensure that the peer was not rebooted. */
|
|
if (!(req->rq_state & RQ_NET_OK)) {
|
|
/* FIXME could this possibly be a req->w.cb == w_send_out_of_sync?
|
|
* in that case we must not set RQ_NET_PENDING. */
|
|
|
|
mod_rq_state(req, m, RQ_COMPLETION_SUSP, RQ_NET_QUEUED|RQ_NET_PENDING);
|
|
if (req->w.cb) {
|
|
drbd_queue_work(&mdev->tconn->sender_work, &req->w);
|
|
rv = req->rq_state & RQ_WRITE ? MR_WRITE : MR_READ;
|
|
} /* else: FIXME can this happen? */
|
|
break;
|
|
}
|
|
/* else, fall through to BARRIER_ACKED */
|
|
|
|
case BARRIER_ACKED:
|
|
/* barrier ack for READ requests does not make sense */
|
|
if (!(req->rq_state & RQ_WRITE))
|
|
break;
|
|
|
|
if (req->rq_state & RQ_NET_PENDING) {
|
|
/* barrier came in before all requests were 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");
|
|
}
|
|
/* Allowed to complete requests, even while suspended.
|
|
* As this is called for all requests within a matching epoch,
|
|
* we need to filter, and only set RQ_NET_DONE for those that
|
|
* have actually been on the wire. */
|
|
mod_rq_state(req, m, RQ_COMPLETION_SUSP,
|
|
(req->rq_state & RQ_NET_MASK) ? RQ_NET_DONE : 0);
|
|
break;
|
|
|
|
case DATA_RECEIVED:
|
|
D_ASSERT(req->rq_state & RQ_NET_PENDING);
|
|
mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK|RQ_NET_DONE);
|
|
break;
|
|
|
|
case QUEUE_AS_DRBD_BARRIER:
|
|
start_new_tl_epoch(mdev->tconn);
|
|
mod_rq_state(req, m, 0, RQ_NET_OK|RQ_NET_DONE);
|
|
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 bool 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 true;
|
|
if (mdev->state.disk != D_INCONSISTENT)
|
|
return false;
|
|
esector = sector + (size >> 9) - 1;
|
|
nr_sectors = drbd_get_capacity(mdev->this_bdev);
|
|
D_ASSERT(sector < nr_sectors);
|
|
D_ASSERT(esector < nr_sectors);
|
|
|
|
sbnr = BM_SECT_TO_BIT(sector);
|
|
ebnr = BM_SECT_TO_BIT(esector);
|
|
|
|
return drbd_bm_count_bits(mdev, sbnr, ebnr) == 0;
|
|
}
|
|
|
|
static bool remote_due_to_read_balancing(struct drbd_conf *mdev, sector_t sector,
|
|
enum drbd_read_balancing rbm)
|
|
{
|
|
struct backing_dev_info *bdi;
|
|
int stripe_shift;
|
|
|
|
switch (rbm) {
|
|
case RB_CONGESTED_REMOTE:
|
|
bdi = &mdev->ldev->backing_bdev->bd_disk->queue->backing_dev_info;
|
|
return bdi_read_congested(bdi);
|
|
case RB_LEAST_PENDING:
|
|
return atomic_read(&mdev->local_cnt) >
|
|
atomic_read(&mdev->ap_pending_cnt) + atomic_read(&mdev->rs_pending_cnt);
|
|
case RB_32K_STRIPING: /* stripe_shift = 15 */
|
|
case RB_64K_STRIPING:
|
|
case RB_128K_STRIPING:
|
|
case RB_256K_STRIPING:
|
|
case RB_512K_STRIPING:
|
|
case RB_1M_STRIPING: /* stripe_shift = 20 */
|
|
stripe_shift = (rbm - RB_32K_STRIPING + 15);
|
|
return (sector >> (stripe_shift - 9)) & 1;
|
|
case RB_ROUND_ROBIN:
|
|
return test_and_change_bit(READ_BALANCE_RR, &mdev->flags);
|
|
case RB_PREFER_REMOTE:
|
|
return true;
|
|
case RB_PREFER_LOCAL:
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*
|
|
* Only way out: remove the conflicting intervals from the tree.
|
|
*/
|
|
static void complete_conflicting_writes(struct drbd_request *req)
|
|
{
|
|
DEFINE_WAIT(wait);
|
|
struct drbd_conf *mdev = req->w.mdev;
|
|
struct drbd_interval *i;
|
|
sector_t sector = req->i.sector;
|
|
int size = req->i.size;
|
|
|
|
i = drbd_find_overlap(&mdev->write_requests, sector, size);
|
|
if (!i)
|
|
return;
|
|
|
|
for (;;) {
|
|
prepare_to_wait(&mdev->misc_wait, &wait, TASK_UNINTERRUPTIBLE);
|
|
i = drbd_find_overlap(&mdev->write_requests, sector, size);
|
|
if (!i)
|
|
break;
|
|
/* Indicate to wake up device->misc_wait on progress. */
|
|
i->waiting = true;
|
|
spin_unlock_irq(&mdev->tconn->req_lock);
|
|
schedule();
|
|
spin_lock_irq(&mdev->tconn->req_lock);
|
|
}
|
|
finish_wait(&mdev->misc_wait, &wait);
|
|
}
|
|
|
|
/* called within req_lock and rcu_read_lock() */
|
|
static void maybe_pull_ahead(struct drbd_conf *mdev)
|
|
{
|
|
struct drbd_tconn *tconn = mdev->tconn;
|
|
struct net_conf *nc;
|
|
bool congested = false;
|
|
enum drbd_on_congestion on_congestion;
|
|
|
|
rcu_read_lock();
|
|
nc = rcu_dereference(tconn->net_conf);
|
|
on_congestion = nc ? nc->on_congestion : OC_BLOCK;
|
|
rcu_read_unlock();
|
|
if (on_congestion == OC_BLOCK ||
|
|
tconn->agreed_pro_version < 96)
|
|
return;
|
|
|
|
/* If I don't even have good local storage, we can not reasonably try
|
|
* to pull ahead of the peer. We also need the local reference to make
|
|
* sure mdev->act_log is there.
|
|
*/
|
|
if (!get_ldev_if_state(mdev, D_UP_TO_DATE))
|
|
return;
|
|
|
|
if (nc->cong_fill &&
|
|
atomic_read(&mdev->ap_in_flight) >= nc->cong_fill) {
|
|
dev_info(DEV, "Congestion-fill threshold reached\n");
|
|
congested = true;
|
|
}
|
|
|
|
if (mdev->act_log->used >= nc->cong_extents) {
|
|
dev_info(DEV, "Congestion-extents threshold reached\n");
|
|
congested = true;
|
|
}
|
|
|
|
if (congested) {
|
|
/* start a new epoch for non-mirrored writes */
|
|
start_new_tl_epoch(mdev->tconn);
|
|
|
|
if (on_congestion == OC_PULL_AHEAD)
|
|
_drbd_set_state(_NS(mdev, conn, C_AHEAD), 0, NULL);
|
|
else /*nc->on_congestion == OC_DISCONNECT */
|
|
_drbd_set_state(_NS(mdev, conn, C_DISCONNECTING), 0, NULL);
|
|
}
|
|
put_ldev(mdev);
|
|
}
|
|
|
|
/* If this returns false, and req->private_bio is still set,
|
|
* this should be submitted locally.
|
|
*
|
|
* If it returns false, but req->private_bio is not set,
|
|
* we do not have access to good data :(
|
|
*
|
|
* Otherwise, this destroys req->private_bio, if any,
|
|
* and returns true.
|
|
*/
|
|
static bool do_remote_read(struct drbd_request *req)
|
|
{
|
|
struct drbd_conf *mdev = req->w.mdev;
|
|
enum drbd_read_balancing rbm;
|
|
|
|
if (req->private_bio) {
|
|
if (!drbd_may_do_local_read(mdev,
|
|
req->i.sector, req->i.size)) {
|
|
bio_put(req->private_bio);
|
|
req->private_bio = NULL;
|
|
put_ldev(mdev);
|
|
}
|
|
}
|
|
|
|
if (mdev->state.pdsk != D_UP_TO_DATE)
|
|
return false;
|
|
|
|
if (req->private_bio == NULL)
|
|
return true;
|
|
|
|
/* TODO: improve read balancing decisions, take into account drbd
|
|
* protocol, pending requests etc. */
|
|
|
|
rcu_read_lock();
|
|
rbm = rcu_dereference(mdev->ldev->disk_conf)->read_balancing;
|
|
rcu_read_unlock();
|
|
|
|
if (rbm == RB_PREFER_LOCAL && req->private_bio)
|
|
return false; /* submit locally */
|
|
|
|
if (remote_due_to_read_balancing(mdev, req->i.sector, rbm)) {
|
|
if (req->private_bio) {
|
|
bio_put(req->private_bio);
|
|
req->private_bio = NULL;
|
|
put_ldev(mdev);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/* returns number of connections (== 1, for drbd 8.4)
|
|
* expected to actually write this data,
|
|
* which does NOT include those that we are L_AHEAD for. */
|
|
static int drbd_process_write_request(struct drbd_request *req)
|
|
{
|
|
struct drbd_conf *mdev = req->w.mdev;
|
|
int remote, send_oos;
|
|
|
|
remote = drbd_should_do_remote(mdev->state);
|
|
send_oos = drbd_should_send_out_of_sync(mdev->state);
|
|
|
|
/* Need to replicate writes. Unless it is an empty flush,
|
|
* which is better mapped to a DRBD P_BARRIER packet,
|
|
* also for drbd wire protocol compatibility reasons.
|
|
* If this was a flush, just start a new epoch.
|
|
* Unless the current epoch was empty anyways, or we are not currently
|
|
* replicating, in which case there is no point. */
|
|
if (unlikely(req->i.size == 0)) {
|
|
/* The only size==0 bios we expect are empty flushes. */
|
|
D_ASSERT(req->master_bio->bi_rw & REQ_FLUSH);
|
|
if (remote)
|
|
_req_mod(req, QUEUE_AS_DRBD_BARRIER);
|
|
return remote;
|
|
}
|
|
|
|
if (!remote && !send_oos)
|
|
return 0;
|
|
|
|
D_ASSERT(!(remote && send_oos));
|
|
|
|
if (remote) {
|
|
_req_mod(req, TO_BE_SENT);
|
|
_req_mod(req, QUEUE_FOR_NET_WRITE);
|
|
} else if (drbd_set_out_of_sync(mdev, req->i.sector, req->i.size))
|
|
_req_mod(req, QUEUE_FOR_SEND_OOS);
|
|
|
|
return remote;
|
|
}
|
|
|
|
static void
|
|
drbd_submit_req_private_bio(struct drbd_request *req)
|
|
{
|
|
struct drbd_conf *mdev = req->w.mdev;
|
|
struct bio *bio = req->private_bio;
|
|
const int rw = bio_rw(bio);
|
|
|
|
bio->bi_bdev = mdev->ldev->backing_bdev;
|
|
|
|
/* State may have changed since we grabbed our reference on the
|
|
* ->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(bio, -EIO);
|
|
else
|
|
generic_make_request(bio);
|
|
put_ldev(mdev);
|
|
} else
|
|
bio_endio(bio, -EIO);
|
|
}
|
|
|
|
static void drbd_queue_write(struct drbd_conf *mdev, struct drbd_request *req)
|
|
{
|
|
spin_lock(&mdev->submit.lock);
|
|
list_add_tail(&req->tl_requests, &mdev->submit.writes);
|
|
spin_unlock(&mdev->submit.lock);
|
|
queue_work(mdev->submit.wq, &mdev->submit.worker);
|
|
}
|
|
|
|
/* returns the new drbd_request pointer, if the caller is expected to
|
|
* drbd_send_and_submit() it (to save latency), or NULL if we queued the
|
|
* request on the submitter thread.
|
|
* Returns ERR_PTR(-ENOMEM) if we cannot allocate a drbd_request.
|
|
*/
|
|
struct drbd_request *
|
|
drbd_request_prepare(struct drbd_conf *mdev, struct bio *bio, unsigned long start_time)
|
|
{
|
|
const int rw = bio_data_dir(bio);
|
|
struct drbd_request *req;
|
|
|
|
/* 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 ERR_PTR(-ENOMEM);
|
|
}
|
|
req->start_time = start_time;
|
|
|
|
if (!get_ldev(mdev)) {
|
|
bio_put(req->private_bio);
|
|
req->private_bio = NULL;
|
|
}
|
|
|
|
/* Update disk stats */
|
|
_drbd_start_io_acct(mdev, req);
|
|
|
|
if (rw == WRITE && req->private_bio && req->i.size
|
|
&& !test_bit(AL_SUSPENDED, &mdev->flags)) {
|
|
if (!drbd_al_begin_io_fastpath(mdev, &req->i)) {
|
|
drbd_queue_write(mdev, req);
|
|
return NULL;
|
|
}
|
|
req->rq_state |= RQ_IN_ACT_LOG;
|
|
}
|
|
|
|
return req;
|
|
}
|
|
|
|
static void drbd_send_and_submit(struct drbd_conf *mdev, struct drbd_request *req)
|
|
{
|
|
const int rw = bio_rw(req->master_bio);
|
|
struct bio_and_error m = { NULL, };
|
|
bool no_remote = false;
|
|
|
|
spin_lock_irq(&mdev->tconn->req_lock);
|
|
if (rw == WRITE) {
|
|
/* This may temporarily give up the req_lock,
|
|
* but will re-aquire it before it returns here.
|
|
* Needs to be before the check on drbd_suspended() */
|
|
complete_conflicting_writes(req);
|
|
/* no more giving up req_lock from now on! */
|
|
|
|
/* check for congestion, and potentially stop sending
|
|
* full data updates, but start sending "dirty bits" only. */
|
|
maybe_pull_ahead(mdev);
|
|
}
|
|
|
|
|
|
if (drbd_suspended(mdev)) {
|
|
/* push back and retry: */
|
|
req->rq_state |= RQ_POSTPONED;
|
|
if (req->private_bio) {
|
|
bio_put(req->private_bio);
|
|
req->private_bio = NULL;
|
|
put_ldev(mdev);
|
|
}
|
|
goto out;
|
|
}
|
|
|
|
/* We fail READ/READA early, if we can not serve it.
|
|
* We must do this before req is registered on any lists.
|
|
* Otherwise, drbd_req_complete() will queue failed READ for retry. */
|
|
if (rw != WRITE) {
|
|
if (!do_remote_read(req) && !req->private_bio)
|
|
goto nodata;
|
|
}
|
|
|
|
/* which transfer log epoch does this belong to? */
|
|
req->epoch = atomic_read(&mdev->tconn->current_tle_nr);
|
|
|
|
/* no point in adding empty flushes to the transfer log,
|
|
* they are mapped to drbd barriers already. */
|
|
if (likely(req->i.size!=0)) {
|
|
if (rw == WRITE)
|
|
mdev->tconn->current_tle_writes++;
|
|
|
|
list_add_tail(&req->tl_requests, &mdev->tconn->transfer_log);
|
|
}
|
|
|
|
if (rw == WRITE) {
|
|
if (!drbd_process_write_request(req))
|
|
no_remote = true;
|
|
} else {
|
|
/* We either have a private_bio, or we can read from remote.
|
|
* Otherwise we had done the goto nodata above. */
|
|
if (req->private_bio == NULL) {
|
|
_req_mod(req, TO_BE_SENT);
|
|
_req_mod(req, QUEUE_FOR_NET_READ);
|
|
} else
|
|
no_remote = true;
|
|
}
|
|
|
|
if (req->private_bio) {
|
|
/* needs to be marked within the same spinlock */
|
|
_req_mod(req, TO_BE_SUBMITTED);
|
|
/* but we need to give up the spinlock to submit */
|
|
spin_unlock_irq(&mdev->tconn->req_lock);
|
|
drbd_submit_req_private_bio(req);
|
|
spin_lock_irq(&mdev->tconn->req_lock);
|
|
} else if (no_remote) {
|
|
nodata:
|
|
if (__ratelimit(&drbd_ratelimit_state))
|
|
dev_err(DEV, "IO ERROR: neither local nor remote data, sector %llu+%u\n",
|
|
(unsigned long long)req->i.sector, req->i.size >> 9);
|
|
/* A write may have been queued for send_oos, however.
|
|
* So we can not simply free it, we must go through drbd_req_put_completion_ref() */
|
|
}
|
|
|
|
out:
|
|
if (drbd_req_put_completion_ref(req, &m, 1))
|
|
kref_put(&req->kref, drbd_req_destroy);
|
|
spin_unlock_irq(&mdev->tconn->req_lock);
|
|
|
|
if (m.bio)
|
|
complete_master_bio(mdev, &m);
|
|
}
|
|
|
|
void __drbd_make_request(struct drbd_conf *mdev, struct bio *bio, unsigned long start_time)
|
|
{
|
|
struct drbd_request *req = drbd_request_prepare(mdev, bio, start_time);
|
|
if (IS_ERR_OR_NULL(req))
|
|
return;
|
|
drbd_send_and_submit(mdev, req);
|
|
}
|
|
|
|
static void submit_fast_path(struct drbd_conf *mdev, struct list_head *incoming)
|
|
{
|
|
struct drbd_request *req, *tmp;
|
|
list_for_each_entry_safe(req, tmp, incoming, tl_requests) {
|
|
const int rw = bio_data_dir(req->master_bio);
|
|
|
|
if (rw == WRITE /* rw != WRITE should not even end up here! */
|
|
&& req->private_bio && req->i.size
|
|
&& !test_bit(AL_SUSPENDED, &mdev->flags)) {
|
|
if (!drbd_al_begin_io_fastpath(mdev, &req->i))
|
|
continue;
|
|
|
|
req->rq_state |= RQ_IN_ACT_LOG;
|
|
}
|
|
|
|
list_del_init(&req->tl_requests);
|
|
drbd_send_and_submit(mdev, req);
|
|
}
|
|
}
|
|
|
|
static bool prepare_al_transaction_nonblock(struct drbd_conf *mdev,
|
|
struct list_head *incoming,
|
|
struct list_head *pending)
|
|
{
|
|
struct drbd_request *req, *tmp;
|
|
int wake = 0;
|
|
int err;
|
|
|
|
spin_lock_irq(&mdev->al_lock);
|
|
list_for_each_entry_safe(req, tmp, incoming, tl_requests) {
|
|
err = drbd_al_begin_io_nonblock(mdev, &req->i);
|
|
if (err == -EBUSY)
|
|
wake = 1;
|
|
if (err)
|
|
continue;
|
|
req->rq_state |= RQ_IN_ACT_LOG;
|
|
list_move_tail(&req->tl_requests, pending);
|
|
}
|
|
spin_unlock_irq(&mdev->al_lock);
|
|
if (wake)
|
|
wake_up(&mdev->al_wait);
|
|
|
|
return !list_empty(pending);
|
|
}
|
|
|
|
void do_submit(struct work_struct *ws)
|
|
{
|
|
struct drbd_conf *mdev = container_of(ws, struct drbd_conf, submit.worker);
|
|
LIST_HEAD(incoming);
|
|
LIST_HEAD(pending);
|
|
struct drbd_request *req, *tmp;
|
|
|
|
for (;;) {
|
|
spin_lock(&mdev->submit.lock);
|
|
list_splice_tail_init(&mdev->submit.writes, &incoming);
|
|
spin_unlock(&mdev->submit.lock);
|
|
|
|
submit_fast_path(mdev, &incoming);
|
|
if (list_empty(&incoming))
|
|
break;
|
|
|
|
wait_event(mdev->al_wait, prepare_al_transaction_nonblock(mdev, &incoming, &pending));
|
|
/* Maybe more was queued, while we prepared the transaction?
|
|
* Try to stuff them into this transaction as well.
|
|
* Be strictly non-blocking here, no wait_event, we already
|
|
* have something to commit.
|
|
* Stop if we don't make any more progres.
|
|
*/
|
|
for (;;) {
|
|
LIST_HEAD(more_pending);
|
|
LIST_HEAD(more_incoming);
|
|
bool made_progress;
|
|
|
|
/* It is ok to look outside the lock,
|
|
* it's only an optimization anyways */
|
|
if (list_empty(&mdev->submit.writes))
|
|
break;
|
|
|
|
spin_lock(&mdev->submit.lock);
|
|
list_splice_tail_init(&mdev->submit.writes, &more_incoming);
|
|
spin_unlock(&mdev->submit.lock);
|
|
|
|
if (list_empty(&more_incoming))
|
|
break;
|
|
|
|
made_progress = prepare_al_transaction_nonblock(mdev, &more_incoming, &more_pending);
|
|
|
|
list_splice_tail_init(&more_pending, &pending);
|
|
list_splice_tail_init(&more_incoming, &incoming);
|
|
|
|
if (!made_progress)
|
|
break;
|
|
}
|
|
drbd_al_begin_io_commit(mdev, false);
|
|
|
|
list_for_each_entry_safe(req, tmp, &pending, tl_requests) {
|
|
list_del_init(&req->tl_requests);
|
|
drbd_send_and_submit(mdev, req);
|
|
}
|
|
}
|
|
}
|
|
|
|
void drbd_make_request(struct request_queue *q, struct bio *bio)
|
|
{
|
|
struct drbd_conf *mdev = (struct drbd_conf *) q->queuedata;
|
|
unsigned long start_time;
|
|
|
|
start_time = jiffies;
|
|
|
|
/*
|
|
* what we "blindly" assume:
|
|
*/
|
|
D_ASSERT(IS_ALIGNED(bio->bi_size, 512));
|
|
|
|
inc_ap_bio(mdev);
|
|
__drbd_make_request(mdev, bio, start_time);
|
|
}
|
|
|
|
/* This is called by bio_add_page().
|
|
*
|
|
* q->max_hw_sectors and other global limits are already enforced there.
|
|
*
|
|
* We need to call down to our lower level device,
|
|
* in case it has special restrictions.
|
|
*
|
|
* We also may need to enforce configured max-bio-bvecs limits.
|
|
*
|
|
* As long as the BIO is empty we have to allow at least one bvec,
|
|
* regardless of size and offset, so no need to ask lower levels.
|
|
*/
|
|
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_size = bvm->bi_size;
|
|
int limit = DRBD_MAX_BIO_SIZE;
|
|
int backing_limit;
|
|
|
|
if (bio_size && get_ldev(mdev)) {
|
|
unsigned int max_hw_sectors = queue_max_hw_sectors(q);
|
|
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);
|
|
if ((limit >> 9) > max_hw_sectors)
|
|
limit = max_hw_sectors << 9;
|
|
}
|
|
return limit;
|
|
}
|
|
|
|
struct drbd_request *find_oldest_request(struct drbd_tconn *tconn)
|
|
{
|
|
/* Walk the transfer log,
|
|
* and find the oldest not yet completed request */
|
|
struct drbd_request *r;
|
|
list_for_each_entry(r, &tconn->transfer_log, tl_requests) {
|
|
if (atomic_read(&r->completion_ref))
|
|
return r;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
void request_timer_fn(unsigned long data)
|
|
{
|
|
struct drbd_conf *mdev = (struct drbd_conf *) data;
|
|
struct drbd_tconn *tconn = mdev->tconn;
|
|
struct drbd_request *req; /* oldest request */
|
|
struct net_conf *nc;
|
|
unsigned long ent = 0, dt = 0, et, nt; /* effective timeout = ko_count * timeout */
|
|
unsigned long now;
|
|
|
|
rcu_read_lock();
|
|
nc = rcu_dereference(tconn->net_conf);
|
|
if (nc && mdev->state.conn >= C_WF_REPORT_PARAMS)
|
|
ent = nc->timeout * HZ/10 * nc->ko_count;
|
|
|
|
if (get_ldev(mdev)) { /* implicit state.disk >= D_INCONSISTENT */
|
|
dt = rcu_dereference(mdev->ldev->disk_conf)->disk_timeout * HZ / 10;
|
|
put_ldev(mdev);
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
et = min_not_zero(dt, ent);
|
|
|
|
if (!et)
|
|
return; /* Recurring timer stopped */
|
|
|
|
now = jiffies;
|
|
|
|
spin_lock_irq(&tconn->req_lock);
|
|
req = find_oldest_request(tconn);
|
|
if (!req) {
|
|
spin_unlock_irq(&tconn->req_lock);
|
|
mod_timer(&mdev->request_timer, now + et);
|
|
return;
|
|
}
|
|
|
|
/* The request is considered timed out, if
|
|
* - we have some effective timeout from the configuration,
|
|
* with above state restrictions applied,
|
|
* - the oldest request is waiting for a response from the network
|
|
* resp. the local disk,
|
|
* - the oldest request is in fact older than the effective timeout,
|
|
* - the connection was established (resp. disk was attached)
|
|
* for longer than the timeout already.
|
|
* Note that for 32bit jiffies and very stable connections/disks,
|
|
* we may have a wrap around, which is catched by
|
|
* !time_in_range(now, last_..._jif, last_..._jif + timeout).
|
|
*
|
|
* Side effect: once per 32bit wrap-around interval, which means every
|
|
* ~198 days with 250 HZ, we have a window where the timeout would need
|
|
* to expire twice (worst case) to become effective. Good enough.
|
|
*/
|
|
if (ent && req->rq_state & RQ_NET_PENDING &&
|
|
time_after(now, req->start_time + ent) &&
|
|
!time_in_range(now, tconn->last_reconnect_jif, tconn->last_reconnect_jif + ent)) {
|
|
dev_warn(DEV, "Remote failed to finish a request within ko-count * timeout\n");
|
|
_drbd_set_state(_NS(mdev, conn, C_TIMEOUT), CS_VERBOSE | CS_HARD, NULL);
|
|
}
|
|
if (dt && req->rq_state & RQ_LOCAL_PENDING && req->w.mdev == mdev &&
|
|
time_after(now, req->start_time + dt) &&
|
|
!time_in_range(now, mdev->last_reattach_jif, mdev->last_reattach_jif + dt)) {
|
|
dev_warn(DEV, "Local backing device failed to meet the disk-timeout\n");
|
|
__drbd_chk_io_error(mdev, DRBD_FORCE_DETACH);
|
|
}
|
|
nt = (time_after(now, req->start_time + et) ? now : req->start_time) + et;
|
|
spin_unlock_irq(&tconn->req_lock);
|
|
mod_timer(&mdev->request_timer, nt);
|
|
}
|