| /* |
| drbd_req.c |
| |
| This file is part of DRBD by Philipp Reisner and Lars Ellenberg. |
| |
| Copyright (C) 2001-2008, LINBIT Information Technologies GmbH. |
| Copyright (C) 1999-2008, Philipp Reisner <philipp.reisner@linbit.com>. |
| Copyright (C) 2002-2008, Lars Ellenberg <lars.ellenberg@linbit.com>. |
| |
| drbd is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| drbd is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with drbd; see the file COPYING. If not, write to |
| the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
| |
| */ |
| |
| #include <linux/module.h> |
| |
| #include <linux/slab.h> |
| #include <linux/drbd.h> |
| #include "drbd_int.h" |
| #include "drbd_req.h" |
| |
| |
| /* Update disk stats at start of I/O request */ |
| static void _drbd_start_io_acct(struct drbd_conf *mdev, struct drbd_request *req, struct bio *bio) |
| { |
| const int rw = bio_data_dir(bio); |
| int cpu; |
| cpu = part_stat_lock(); |
| part_round_stats(cpu, &mdev->vdisk->part0); |
| part_stat_inc(cpu, &mdev->vdisk->part0, ios[rw]); |
| part_stat_add(cpu, &mdev->vdisk->part0, sectors[rw], bio_sectors(bio)); |
| part_inc_in_flight(&mdev->vdisk->part0, rw); |
| part_stat_unlock(); |
| } |
| |
| /* Update disk stats when completing request upwards */ |
| static void _drbd_end_io_acct(struct drbd_conf *mdev, struct drbd_request *req) |
| { |
| int rw = bio_data_dir(req->master_bio); |
| unsigned long duration = jiffies - req->start_time; |
| int cpu; |
| cpu = part_stat_lock(); |
| part_stat_add(cpu, &mdev->vdisk->part0, ticks[rw], duration); |
| part_round_stats(cpu, &mdev->vdisk->part0); |
| part_dec_in_flight(&mdev->vdisk->part0, rw); |
| part_stat_unlock(); |
| } |
| |
| static void _req_is_done(struct drbd_conf *mdev, struct drbd_request *req, const int rw) |
| { |
| const unsigned long s = req->rq_state; |
| |
| /* remove it from the transfer log. |
| * well, only if it had been there in the first |
| * place... if it had not (local only or conflicting |
| * and never sent), it should still be "empty" as |
| * initialized in drbd_req_new(), so we can list_del() it |
| * here unconditionally */ |
| list_del(&req->tl_requests); |
| |
| /* if it was a write, we may have to set the corresponding |
| * bit(s) out-of-sync first. If it had a local part, we need to |
| * release the reference to the activity log. */ |
| if (rw == WRITE) { |
| /* Set out-of-sync unless both OK flags are set |
| * (local only or remote failed). |
| * Other places where we set out-of-sync: |
| * READ with local io-error */ |
| if (!(s & RQ_NET_OK) || !(s & RQ_LOCAL_OK)) |
| drbd_set_out_of_sync(mdev, req->sector, req->size); |
| |
| if ((s & RQ_NET_OK) && (s & RQ_LOCAL_OK) && (s & RQ_NET_SIS)) |
| drbd_set_in_sync(mdev, req->sector, req->size); |
| |
| /* one might be tempted to move the drbd_al_complete_io |
| * to the local io completion callback drbd_endio_pri. |
| * but, if this was a mirror write, we may only |
| * drbd_al_complete_io after this is RQ_NET_DONE, |
| * otherwise the extent could be dropped from the al |
| * before it has actually been written on the peer. |
| * if we crash before our peer knows about the request, |
| * but after the extent has been dropped from the al, |
| * we would forget to resync the corresponding extent. |
| */ |
| if (s & RQ_LOCAL_MASK) { |
| if (get_ldev_if_state(mdev, D_FAILED)) { |
| if (s & RQ_IN_ACT_LOG) |
| drbd_al_complete_io(mdev, req->sector); |
| put_ldev(mdev); |
| } else if (__ratelimit(&drbd_ratelimit_state)) { |
| dev_warn(DEV, "Should have called drbd_al_complete_io(, %llu), " |
| "but my Disk seems to have failed :(\n", |
| (unsigned long long) req->sector); |
| } |
| } |
| } |
| |
| drbd_req_free(req); |
| } |
| |
| static void queue_barrier(struct drbd_conf *mdev) |
| { |
| struct drbd_tl_epoch *b; |
| |
| /* We are within the req_lock. Once we queued the barrier for sending, |
| * we set the CREATE_BARRIER bit. It is cleared as soon as a new |
| * barrier/epoch object is added. This is the only place this bit is |
| * set. It indicates that the barrier for this epoch is already queued, |
| * and no new epoch has been created yet. */ |
| if (drbd_test_flag(mdev, CREATE_BARRIER)) |
| return; |
| |
| b = mdev->newest_tle; |
| b->w.cb = w_send_barrier; |
| /* inc_ap_pending done here, so we won't |
| * get imbalanced on connection loss. |
| * dec_ap_pending will be done in got_BarrierAck |
| * or (on connection loss) in tl_clear. */ |
| inc_ap_pending(mdev); |
| drbd_queue_work(&mdev->data.work, &b->w); |
| drbd_set_flag(mdev, CREATE_BARRIER); |
| } |
| |
| static void _about_to_complete_local_write(struct drbd_conf *mdev, |
| struct drbd_request *req) |
| { |
| const unsigned long s = req->rq_state; |
| struct drbd_request *i; |
| struct drbd_epoch_entry *e; |
| struct hlist_node *n; |
| struct hlist_head *slot; |
| |
| /* Before we can signal completion to the upper layers, |
| * we may need to close the current epoch. |
| * We can skip this, if this request has not even been sent, because we |
| * did not have a fully established connection yet/anymore, during |
| * bitmap exchange, or while we are C_AHEAD due to congestion policy. |
| */ |
| if (mdev->state.conn >= C_CONNECTED && |
| (s & RQ_NET_SENT) != 0 && |
| req->epoch == mdev->newest_tle->br_number) |
| queue_barrier(mdev); |
| |
| /* we need to do the conflict detection stuff, |
| * if we have the ee_hash (two_primaries) and |
| * this has been on the network */ |
| if ((s & RQ_NET_DONE) && mdev->ee_hash != NULL) { |
| const sector_t sector = req->sector; |
| const int size = req->size; |
| |
| /* ASSERT: |
| * there must be no conflicting requests, since |
| * they must have been failed on the spot */ |
| #define OVERLAPS overlaps(sector, size, i->sector, i->size) |
| slot = tl_hash_slot(mdev, sector); |
| hlist_for_each_entry(i, n, slot, collision) { |
| if (OVERLAPS) { |
| dev_alert(DEV, "LOGIC BUG: completed: %p %llus +%u; " |
| "other: %p %llus +%u\n", |
| req, (unsigned long long)sector, size, |
| i, (unsigned long long)i->sector, i->size); |
| } |
| } |
| |
| /* maybe "wake" those conflicting epoch entries |
| * that wait for this request to finish. |
| * |
| * currently, there can be only _one_ such ee |
| * (well, or some more, which would be pending |
| * P_DISCARD_ACK not yet sent by the asender...), |
| * since we block the receiver thread upon the |
| * first conflict detection, which will wait on |
| * misc_wait. maybe we want to assert that? |
| * |
| * anyways, if we found one, |
| * we just have to do a wake_up. */ |
| #undef OVERLAPS |
| #define OVERLAPS overlaps(sector, size, e->sector, e->size) |
| slot = ee_hash_slot(mdev, req->sector); |
| hlist_for_each_entry(e, n, slot, collision) { |
| if (OVERLAPS) { |
| wake_up(&mdev->misc_wait); |
| break; |
| } |
| } |
| } |
| #undef OVERLAPS |
| } |
| |
| void complete_master_bio(struct drbd_conf *mdev, |
| struct bio_and_error *m) |
| { |
| bio_endio(m->bio, m->error); |
| dec_ap_bio(mdev); |
| } |
| |
| /* Helper for __req_mod(). |
| * Set m->bio to the master bio, if it is fit to be completed, |
| * or leave it alone (it is initialized to NULL in __req_mod), |
| * if it has already been completed, or cannot be completed yet. |
| * If m->bio is set, the error status to be returned is placed in m->error. |
| */ |
| void _req_may_be_done(struct drbd_request *req, struct bio_and_error *m) |
| { |
| const unsigned long s = req->rq_state; |
| struct drbd_conf *mdev = req->mdev; |
| int rw = req->rq_state & RQ_WRITE ? WRITE : READ; |
| |
| /* we must not complete the master bio, while it is |
| * still being processed by _drbd_send_zc_bio (drbd_send_dblock) |
| * not yet acknowledged by the peer |
| * not yet completed by the local io subsystem |
| * these flags may get cleared in any order by |
| * the worker, |
| * the receiver, |
| * the bio_endio completion callbacks. |
| */ |
| if (s & RQ_NET_QUEUED) |
| return; |
| if (s & RQ_NET_PENDING) |
| return; |
| if (s & RQ_LOCAL_PENDING && !(s & RQ_LOCAL_ABORTED)) |
| return; |
| |
| if (req->master_bio) { |
| /* this is data_received (remote read) |
| * or protocol C P_WRITE_ACK |
| * or protocol B P_RECV_ACK |
| * or protocol A "handed_over_to_network" (SendAck) |
| * or canceled or failed, |
| * or killed from the transfer log due to connection loss. |
| */ |
| |
| /* |
| * figure out whether to report success or failure. |
| * |
| * report success when at least one of the operations succeeded. |
| * or, to put the other way, |
| * only report failure, when both operations failed. |
| * |
| * what to do about the failures is handled elsewhere. |
| * what we need to do here is just: complete the master_bio. |
| * |
| * local completion error, if any, has been stored as ERR_PTR |
| * in private_bio within drbd_endio_pri. |
| */ |
| int ok = (s & RQ_LOCAL_OK) || (s & RQ_NET_OK); |
| int error = PTR_ERR(req->private_bio); |
| |
| /* remove the request from the conflict detection |
| * respective block_id verification hash */ |
| if (!hlist_unhashed(&req->collision)) |
| hlist_del(&req->collision); |
| else |
| D_ASSERT((s & (RQ_NET_MASK & ~RQ_NET_DONE)) == 0); |
| |
| /* for writes we need to do some extra housekeeping */ |
| if (rw == WRITE) |
| _about_to_complete_local_write(mdev, req); |
| |
| /* Update disk stats */ |
| _drbd_end_io_acct(mdev, req); |
| |
| m->error = ok ? 0 : (error ?: -EIO); |
| m->bio = req->master_bio; |
| req->master_bio = NULL; |
| } |
| |
| if (s & RQ_LOCAL_PENDING) |
| return; |
| |
| if ((s & RQ_NET_MASK) == 0 || (s & RQ_NET_DONE)) { |
| /* this is disconnected (local only) operation, |
| * or protocol C P_WRITE_ACK, |
| * or protocol A or B P_BARRIER_ACK, |
| * or killed from the transfer log due to connection loss. */ |
| _req_is_done(mdev, req, rw); |
| } |
| /* else: network part and not DONE yet. that is |
| * protocol A or B, barrier ack still pending... */ |
| } |
| |
| static void _req_may_be_done_not_susp(struct drbd_request *req, struct bio_and_error *m) |
| { |
| struct drbd_conf *mdev = req->mdev; |
| |
| if (!is_susp(mdev->state)) |
| _req_may_be_done(req, m); |
| } |
| |
| /* |
| * checks whether there was an overlapping request |
| * or ee already registered. |
| * |
| * if so, return 1, in which case this request is completed on the spot, |
| * without ever being submitted or send. |
| * |
| * return 0 if it is ok to submit this request. |
| * |
| * NOTE: |
| * paranoia: assume something above us is broken, and issues different write |
| * requests for the same block simultaneously... |
| * |
| * To ensure these won't be reordered differently on both nodes, resulting in |
| * diverging data sets, we discard the later one(s). Not that this is supposed |
| * to happen, but this is the rationale why we also have to check for |
| * conflicting requests with local origin, and why we have to do so regardless |
| * of whether we allowed multiple primaries. |
| * |
| * BTW, in case we only have one primary, the ee_hash is empty anyways, and the |
| * second hlist_for_each_entry becomes a noop. This is even simpler than to |
| * grab a reference on the net_conf, and check for the two_primaries flag... |
| */ |
| static int _req_conflicts(struct drbd_request *req) |
| { |
| struct drbd_conf *mdev = req->mdev; |
| const sector_t sector = req->sector; |
| const int size = req->size; |
| struct drbd_request *i; |
| struct drbd_epoch_entry *e; |
| struct hlist_node *n; |
| struct hlist_head *slot; |
| |
| D_ASSERT(hlist_unhashed(&req->collision)); |
| |
| if (!get_net_conf(mdev)) |
| return 0; |
| |
| /* BUG_ON */ |
| ERR_IF (mdev->tl_hash_s == 0) |
| goto out_no_conflict; |
| BUG_ON(mdev->tl_hash == NULL); |
| |
| #define OVERLAPS overlaps(i->sector, i->size, sector, size) |
| slot = tl_hash_slot(mdev, sector); |
| hlist_for_each_entry(i, n, slot, collision) { |
| if (OVERLAPS) { |
| dev_alert(DEV, "%s[%u] Concurrent local write detected! " |
| "[DISCARD L] new: %llus +%u; " |
| "pending: %llus +%u\n", |
| current->comm, current->pid, |
| (unsigned long long)sector, size, |
| (unsigned long long)i->sector, i->size); |
| goto out_conflict; |
| } |
| } |
| |
| if (mdev->ee_hash_s) { |
| /* now, check for overlapping requests with remote origin */ |
| BUG_ON(mdev->ee_hash == NULL); |
| #undef OVERLAPS |
| #define OVERLAPS overlaps(e->sector, e->size, sector, size) |
| slot = ee_hash_slot(mdev, sector); |
| hlist_for_each_entry(e, n, slot, collision) { |
| if (OVERLAPS) { |
| dev_alert(DEV, "%s[%u] Concurrent remote write detected!" |
| " [DISCARD L] new: %llus +%u; " |
| "pending: %llus +%u\n", |
| current->comm, current->pid, |
| (unsigned long long)sector, size, |
| (unsigned long long)e->sector, e->size); |
| goto out_conflict; |
| } |
| } |
| } |
| #undef OVERLAPS |
| |
| out_no_conflict: |
| /* this is like it should be, and what we expected. |
| * our users do behave after all... */ |
| put_net_conf(mdev); |
| return 0; |
| |
| out_conflict: |
| put_net_conf(mdev); |
| return 1; |
| } |
| |
| /* obviously this could be coded as many single functions |
| * instead of one huge switch, |
| * or by putting the code directly in the respective locations |
| * (as it has been before). |
| * |
| * but having it this way |
| * enforces that it is all in this one place, where it is easier to audit, |
| * it makes it obvious that whatever "event" "happens" to a request should |
| * happen "atomically" within the req_lock, |
| * and it enforces that we have to think in a very structured manner |
| * about the "events" that may happen to a request during its life time ... |
| */ |
| int __req_mod(struct drbd_request *req, enum drbd_req_event what, |
| struct bio_and_error *m) |
| { |
| struct drbd_conf *mdev = req->mdev; |
| int rv = 0; |
| m->bio = NULL; |
| |
| switch (what) { |
| default: |
| dev_err(DEV, "LOGIC BUG in %s:%u\n", __FILE__ , __LINE__); |
| break; |
| |
| /* does not happen... |
| * initialization done in drbd_req_new |
| case created: |
| break; |
| */ |
| |
| case to_be_send: /* via network */ |
| /* reached via drbd_make_request_common |
| * and from w_read_retry_remote */ |
| D_ASSERT(!(req->rq_state & RQ_NET_MASK)); |
| req->rq_state |= RQ_NET_PENDING; |
| inc_ap_pending(mdev); |
| break; |
| |
| case to_be_submitted: /* locally */ |
| /* reached via drbd_make_request_common */ |
| D_ASSERT(!(req->rq_state & RQ_LOCAL_MASK)); |
| req->rq_state |= RQ_LOCAL_PENDING; |
| break; |
| |
| case completed_ok: |
| if (req->rq_state & RQ_WRITE) |
| mdev->writ_cnt += req->size>>9; |
| else |
| mdev->read_cnt += req->size>>9; |
| |
| req->rq_state |= (RQ_LOCAL_COMPLETED|RQ_LOCAL_OK); |
| req->rq_state &= ~RQ_LOCAL_PENDING; |
| |
| _req_may_be_done_not_susp(req, m); |
| break; |
| |
| case abort_disk_io: |
| req->rq_state |= RQ_LOCAL_ABORTED; |
| if (req->rq_state & RQ_WRITE) |
| _req_may_be_done_not_susp(req, m); |
| else |
| goto goto_queue_for_net_read; |
| break; |
| |
| case write_completed_with_error: |
| req->rq_state |= RQ_LOCAL_COMPLETED; |
| req->rq_state &= ~RQ_LOCAL_PENDING; |
| |
| __drbd_chk_io_error(mdev, DRBD_WRITE_ERROR); |
| _req_may_be_done_not_susp(req, m); |
| break; |
| |
| case read_ahead_completed_with_error: |
| /* it is legal to fail READA */ |
| req->rq_state |= RQ_LOCAL_COMPLETED; |
| req->rq_state &= ~RQ_LOCAL_PENDING; |
| _req_may_be_done_not_susp(req, m); |
| break; |
| |
| case read_completed_with_error: |
| drbd_set_out_of_sync(mdev, req->sector, req->size); |
| |
| req->rq_state |= RQ_LOCAL_COMPLETED; |
| req->rq_state &= ~RQ_LOCAL_PENDING; |
| |
| if (req->rq_state & RQ_LOCAL_ABORTED) { |
| _req_may_be_done(req, m); |
| break; |
| } |
| |
| __drbd_chk_io_error(mdev, DRBD_READ_ERROR); |
| |
| goto_queue_for_net_read: |
| |
| D_ASSERT(!(req->rq_state & RQ_NET_MASK)); |
| |
| /* no point in retrying if there is no good remote data, |
| * or we have no connection. */ |
| if (mdev->state.pdsk != D_UP_TO_DATE) { |
| _req_may_be_done_not_susp(req, m); |
| break; |
| } |
| |
| /* _req_mod(req,to_be_send); oops, recursion... */ |
| req->rq_state |= RQ_NET_PENDING; |
| inc_ap_pending(mdev); |
| /* fall through: _req_mod(req,queue_for_net_read); */ |
| |
| 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_common |
| * or from bio_endio during read io-error recovery */ |
| |
| /* so we can verify the handle in the answer packet |
| * corresponding hlist_del is in _req_may_be_done() */ |
| hlist_add_head(&req->collision, ar_hash_slot(mdev, req->sector)); |
| |
| drbd_set_flag(mdev, UNPLUG_REMOTE); |
| |
| D_ASSERT(req->rq_state & RQ_NET_PENDING); |
| req->rq_state |= RQ_NET_QUEUED; |
| req->w.cb = (req->rq_state & RQ_LOCAL_MASK) |
| ? w_read_retry_remote |
| : w_send_read_req; |
| drbd_queue_work(&mdev->data.work, &req->w); |
| break; |
| |
| case queue_for_net_write: |
| /* assert something? */ |
| /* from drbd_make_request_common only */ |
| |
| hlist_add_head(&req->collision, tl_hash_slot(mdev, req->sector)); |
| /* corresponding hlist_del is in _req_may_be_done() */ |
| |
| /* 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_common, 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. */ |
| drbd_set_flag(mdev, UNPLUG_REMOTE); |
| |
| /* see drbd_make_request_common, |
| * just after it grabs the req_lock */ |
| D_ASSERT(drbd_test_flag(mdev, CREATE_BARRIER) == 0); |
| |
| req->epoch = mdev->newest_tle->br_number; |
| |
| /* increment size of current epoch */ |
| mdev->newest_tle->n_writes++; |
| |
| /* queue work item to send data */ |
| D_ASSERT(req->rq_state & RQ_NET_PENDING); |
| req->rq_state |= RQ_NET_QUEUED; |
| req->w.cb = w_send_dblock; |
| drbd_queue_work(&mdev->data.work, &req->w); |
| |
| /* close the epoch, in case it outgrew the limit */ |
| if (mdev->newest_tle->n_writes >= mdev->net_conf->max_epoch_size) |
| queue_barrier(mdev); |
| |
| break; |
| |
| case queue_for_send_oos: |
| req->rq_state |= RQ_NET_QUEUED; |
| req->w.cb = w_send_oos; |
| drbd_queue_work(&mdev->data.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 */ |
| 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->size>>9, &mdev->ap_in_flight); |
| |
| if (bio_data_dir(req->master_bio) == WRITE && |
| mdev->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; |
| _req_may_be_done_not_susp(req, m); |
| break; |
| |
| case oos_handed_to_network: |
| /* Was not set PENDING, no longer QUEUED, so is now DONE |
| * as far as this connection is concerned. */ |
| req->rq_state &= ~RQ_NET_QUEUED; |
| req->rq_state |= RQ_NET_DONE; |
| _req_may_be_done_not_susp(req, m); |
| break; |
| |
| 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->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 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->sector, req->size); |
| req->rq_state |= RQ_NET_DONE; |
| /* fall through */ |
| case write_acked_by_peer_and_sis: |
| case write_acked_by_peer: |
| if (what == write_acked_by_peer_and_sis) |
| req->rq_state |= RQ_NET_SIS; |
| /* 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. */ |
| |
| 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->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->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->data.work, &req->w); |
| break; |
| |
| case resend: |
| /* Simply complete (local only) READs. */ |
| if (!(req->rq_state & RQ_WRITE) && !req->w.cb) { |
| _req_may_be_done(req, m); |
| 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 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->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->out_of_sequence_requests); |
| } |
| if ((req->rq_state & RQ_NET_MASK) != 0) { |
| req->rq_state |= RQ_NET_DONE; |
| if (mdev->net_conf->wire_protocol == DRBD_PROT_A) |
| atomic_sub(req->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); |
| } |
| |
| static void maybe_pull_ahead(struct drbd_conf *mdev) |
| { |
| int congested = 0; |
| |
| /* 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. |
| * Note: caller has to make sure that net_conf is there. |
| */ |
| if (!get_ldev_if_state(mdev, D_UP_TO_DATE)) |
| return; |
| |
| if (mdev->net_conf->cong_fill && |
| atomic_read(&mdev->ap_in_flight) >= mdev->net_conf->cong_fill) { |
| dev_info(DEV, "Congestion-fill threshold reached\n"); |
| congested = 1; |
| } |
| |
| if (mdev->act_log->used >= mdev->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->net_conf->on_congestion == OC_PULL_AHEAD) |
| _drbd_set_state(_NS(mdev, conn, C_AHEAD), 0, NULL); |
| else /*mdev->net_conf->on_congestion == OC_DISCONNECT */ |
| _drbd_set_state(_NS(mdev, conn, C_DISCONNECTING), 0, NULL); |
| } |
| put_ldev(mdev); |
| } |
| |
| 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 = -EIO; |
| int ret = 0; |
| union drbd_state s; |
| |
| /* 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) { |
| /* 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 (unlikely(size == 0)) { |
| /* The only size==0 bios we expect are empty flushes. */ |
| D_ASSERT(bio->bi_rw & REQ_FLUSH); |
| remote = 0; |
| } else |
| 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. |
| * Empty flushes don't need to go into the activity log, they can only |
| * flush data for pending writes which are already in there. */ |
| if (rw == WRITE && local && size |
| && !drbd_test_flag(mdev, AL_SUSPENDED)) { |
| req->rq_state |= RQ_IN_ACT_LOG; |
| drbd_al_begin_io(mdev, sector); |
| } |
| |
| s = mdev->state; |
| remote = remote && drbd_should_do_remote(s); |
| send_oos = rw == WRITE && drbd_should_send_oos(s); |
| 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"); |
| 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->unused_spare_tle == NULL && |
| drbd_test_flag(mdev, CREATE_BARRIER)) { |
| 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->req_lock); |
| |
| if (is_susp(mdev->state)) { |
| /* If we got suspended, use the retry mechanism of |
| drbd_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->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->req_lock); |
| goto fail_free_complete; |
| } |
| } |
| |
| if (b && mdev->unused_spare_tle == NULL) { |
| mdev->unused_spare_tle = b; |
| b = NULL; |
| } |
| if (rw == WRITE && (remote || send_oos) && |
| mdev->unused_spare_tle == NULL && |
| drbd_test_flag(mdev, CREATE_BARRIER)) { |
| /* someone closed the current epoch |
| * while we were grabbing the spinlock */ |
| spin_unlock_irq(&mdev->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->unused_spare_tle && |
| drbd_test_and_clear_flag(mdev, CREATE_BARRIER)) { |
| _tl_add_barrier(mdev, mdev->unused_spare_tle); |
| mdev->unused_spare_tle = NULL; |
| } else { |
| D_ASSERT(!(remote && rw == WRITE && |
| drbd_test_flag(mdev, CREATE_BARRIER))); |
| } |
| |
| /* 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_send); |
| if (local) |
| _req_mod(req, to_be_submitted); |
| |
| /* check this request on the collision detection hash tables. |
| * if we have a conflict, just complete it here. |
| * THINK do we want to check reads, too? (I don't think so...) */ |
| if (rw == WRITE && _req_conflicts(req)) |
| goto fail_conflicting; |
| |
| /* no point in adding empty flushes to the transfer log, |
| * they are mapped to drbd barriers already. */ |
| if (likely(size!=0)) |
| list_add_tail(&req->tl_requests, &mdev->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->net_conf->on_congestion != OC_BLOCK && mdev->agreed_pro_version >= 96) |
| maybe_pull_ahead(mdev); |
| |
| /* If this was a flush, queue a drbd barrier/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(bio->bi_rw & REQ_FLUSH) |
| && mdev->newest_tle->n_writes |
| && drbd_should_do_remote(mdev->state)) |
| queue_barrier(mdev); |
| |
| spin_unlock_irq(&mdev->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_conflicting: |
| /* this is a conflicting request. |
| * even though it may have been only _partially_ |
| * overlapping with one of the currently pending requests, |
| * without even submitting or sending it, we will |
| * pretend that it was successfully served right now. |
| */ |
| _drbd_end_io_acct(mdev, req); |
| spin_unlock_irq(&mdev->req_lock); |
| if (remote) |
| dec_ap_pending(mdev); |
| /* THINK: do we want to fail it (-EIO), or pretend success? |
| * this pretends success. */ |
| err = 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; |
| } |
| |
| void 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; |
| } |
| |
| start_time = jiffies; |
| |
| /* |
| * what we "blindly" assume: |
| */ |
| D_ASSERT((bio->bi_size & 0x1ff) == 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_size ? (bio->bi_sector+(bio->bi_size>>9)-1) >> HT_SHIFT : s_enr; |
| |
| if (likely(s_enr == e_enr)) { |
| do { |
| inc_ap_bio(mdev, 1); |
| } while (drbd_make_request_common(mdev, bio, start_time)); |
| return; |
| } |
| |
| /* 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); |
| } |
| } |
| |
| /* 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 ent = 0, dt = 0, et, nt; /* effective timeout = ko_count * timeout */ |
| unsigned long now; |
| |
| if (get_net_conf(mdev)) { |
| if (mdev->state.conn >= C_WF_REPORT_PARAMS) |
| ent = mdev->net_conf->timeout*HZ/10 |
| * mdev->net_conf->ko_count; |
| put_net_conf(mdev); |
| } |
| if (get_ldev(mdev)) { /* implicit state.disk >= D_INCONSISTENT */ |
| dt = mdev->ldev->dc.disk_timeout * HZ / 10; |
| put_ldev(mdev); |
| } |
| et = min_not_zero(dt, ent); |
| |
| if (!et) |
| return; /* Recurring timer stopped */ |
| |
| now = jiffies; |
| |
| spin_lock_irq(&mdev->req_lock); |
| le = &mdev->oldest_tle->requests; |
| if (list_empty(le)) { |
| spin_unlock_irq(&mdev->req_lock); |
| mod_timer(&mdev->request_timer, now + et); |
| return; |
| } |
| |
| le = le->prev; |
| req = list_entry(le, struct drbd_request, tl_requests); |
| |
| /* 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, mdev->last_reconnect_jif, mdev->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 && |
| 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(&mdev->req_lock); |
| mod_timer(&mdev->request_timer, nt); |
| } |