| /* |
| 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" |
| |
| |
| static bool drbd_may_do_local_read(struct drbd_device *device, sector_t sector, int size); |
| |
| /* Update disk stats at start of I/O request */ |
| static void _drbd_start_io_acct(struct drbd_device *device, struct drbd_request *req) |
| { |
| struct request_queue *q = device->rq_queue; |
| |
| generic_start_io_acct(q, bio_data_dir(req->master_bio), |
| req->i.size >> 9, &device->vdisk->part0); |
| } |
| |
| /* Update disk stats when completing request upwards */ |
| static void _drbd_end_io_acct(struct drbd_device *device, struct drbd_request *req) |
| { |
| struct request_queue *q = device->rq_queue; |
| |
| generic_end_io_acct(q, bio_data_dir(req->master_bio), |
| &device->vdisk->part0, req->start_jif); |
| } |
| |
| static struct drbd_request *drbd_req_new(struct drbd_device *device, struct bio *bio_src) |
| { |
| struct drbd_request *req; |
| |
| req = mempool_alloc(&drbd_request_mempool, GFP_NOIO); |
| if (!req) |
| return NULL; |
| memset(req, 0, sizeof(*req)); |
| |
| drbd_req_make_private_bio(req, bio_src); |
| req->rq_state = (bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0) |
| | (bio_op(bio_src) == REQ_OP_WRITE_SAME ? RQ_WSAME : 0) |
| | (bio_op(bio_src) == REQ_OP_WRITE_ZEROES ? RQ_UNMAP : 0) |
| | (bio_op(bio_src) == REQ_OP_DISCARD ? RQ_UNMAP : 0); |
| req->device = device; |
| req->master_bio = bio_src; |
| req->epoch = 0; |
| |
| drbd_clear_interval(&req->i); |
| req->i.sector = bio_src->bi_iter.bi_sector; |
| req->i.size = bio_src->bi_iter.bi_size; |
| req->i.local = true; |
| req->i.waiting = false; |
| |
| INIT_LIST_HEAD(&req->tl_requests); |
| INIT_LIST_HEAD(&req->w.list); |
| INIT_LIST_HEAD(&req->req_pending_master_completion); |
| INIT_LIST_HEAD(&req->req_pending_local); |
| |
| /* one reference to be put by __drbd_make_request */ |
| atomic_set(&req->completion_ref, 1); |
| /* one kref as long as completion_ref > 0 */ |
| kref_init(&req->kref); |
| return req; |
| } |
| |
| static void drbd_remove_request_interval(struct rb_root *root, |
| struct drbd_request *req) |
| { |
| struct drbd_device *device = req->device; |
| struct drbd_interval *i = &req->i; |
| |
| drbd_remove_interval(root, i); |
| |
| /* Wake up any processes waiting for this request to complete. */ |
| if (i->waiting) |
| wake_up(&device->misc_wait); |
| } |
| |
| void drbd_req_destroy(struct kref *kref) |
| { |
| struct drbd_request *req = container_of(kref, struct drbd_request, kref); |
| struct drbd_device *device = req->device; |
| const unsigned s = req->rq_state; |
| |
| if ((req->master_bio && !(s & RQ_POSTPONED)) || |
| atomic_read(&req->completion_ref) || |
| (s & RQ_LOCAL_PENDING) || |
| ((s & RQ_NET_MASK) && !(s & RQ_NET_DONE))) { |
| drbd_err(device, "drbd_req_destroy: Logic BUG rq_state = 0x%x, completion_ref = %d\n", |
| s, atomic_read(&req->completion_ref)); |
| return; |
| } |
| |
| /* If called from mod_rq_state (expected normal case) or |
| * drbd_send_and_submit (the less likely normal path), this holds the |
| * req_lock, and req->tl_requests will typicaly be on ->transfer_log, |
| * though it may be still empty (never added to the transfer log). |
| * |
| * If called from do_retry(), we do NOT hold the req_lock, but we are |
| * still allowed to unconditionally list_del(&req->tl_requests), |
| * because it will be on a local on-stack list only. */ |
| list_del_init(&req->tl_requests); |
| |
| /* finally remove the request from the conflict detection |
| * respective block_id verification interval tree. */ |
| if (!drbd_interval_empty(&req->i)) { |
| struct rb_root *root; |
| |
| if (s & RQ_WRITE) |
| root = &device->write_requests; |
| else |
| root = &device->read_requests; |
| drbd_remove_request_interval(root, req); |
| } else if (s & (RQ_NET_MASK & ~RQ_NET_DONE) && req->i.size != 0) |
| drbd_err(device, "drbd_req_destroy: Logic BUG: interval empty, but: rq_state=0x%x, sect=%llu, size=%u\n", |
| s, (unsigned long long)req->i.sector, req->i.size); |
| |
| /* 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 (s & RQ_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 */ |
| |
| /* There is a special case: |
| * we may notice late that IO was suspended, |
| * and postpone, or schedule for retry, a write, |
| * before it even was submitted or sent. |
| * In that case we do not want to touch the bitmap at all. |
| */ |
| if ((s & (RQ_POSTPONED|RQ_LOCAL_MASK|RQ_NET_MASK)) != RQ_POSTPONED) { |
| if (!(s & RQ_NET_OK) || !(s & RQ_LOCAL_OK)) |
| drbd_set_out_of_sync(device, req->i.sector, req->i.size); |
| |
| if ((s & RQ_NET_OK) && (s & RQ_LOCAL_OK) && (s & RQ_NET_SIS)) |
| drbd_set_in_sync(device, req->i.sector, req->i.size); |
| } |
| |
| /* one might be tempted to move the drbd_al_complete_io |
| * to the local io completion callback drbd_request_endio. |
| * 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_IN_ACT_LOG) { |
| if (get_ldev_if_state(device, D_FAILED)) { |
| drbd_al_complete_io(device, &req->i); |
| put_ldev(device); |
| } else if (__ratelimit(&drbd_ratelimit_state)) { |
| drbd_warn(device, "Should have called drbd_al_complete_io(, %llu, %u), " |
| "but my Disk seems to have failed :(\n", |
| (unsigned long long) req->i.sector, req->i.size); |
| } |
| } |
| } |
| |
| mempool_free(req, &drbd_request_mempool); |
| } |
| |
| static void wake_all_senders(struct drbd_connection *connection) |
| { |
| wake_up(&connection->sender_work.q_wait); |
| } |
| |
| /* must hold resource->req_lock */ |
| void start_new_tl_epoch(struct drbd_connection *connection) |
| { |
| /* no point closing an epoch, if it is empty, anyways. */ |
| if (connection->current_tle_writes == 0) |
| return; |
| |
| connection->current_tle_writes = 0; |
| atomic_inc(&connection->current_tle_nr); |
| wake_all_senders(connection); |
| } |
| |
| void complete_master_bio(struct drbd_device *device, |
| struct bio_and_error *m) |
| { |
| m->bio->bi_status = errno_to_blk_status(m->error); |
| bio_endio(m->bio); |
| dec_ap_bio(device); |
| } |
| |
| |
| /* 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. |
| */ |
| static |
| void drbd_req_complete(struct drbd_request *req, struct bio_and_error *m) |
| { |
| const unsigned s = req->rq_state; |
| struct drbd_device *device = req->device; |
| int error, ok; |
| |
| /* 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_LOCAL_PENDING && !(s & RQ_LOCAL_ABORTED)) || |
| (s & RQ_NET_QUEUED) || (s & RQ_NET_PENDING) || |
| (s & RQ_COMPLETION_SUSP)) { |
| drbd_err(device, "drbd_req_complete: Logic BUG rq_state = 0x%x\n", s); |
| return; |
| } |
| |
| if (!req->master_bio) { |
| drbd_err(device, "drbd_req_complete: Logic BUG, master_bio == NULL!\n"); |
| return; |
| } |
| |
| /* |
| * 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_request_endio. |
| */ |
| ok = (s & RQ_LOCAL_OK) || (s & RQ_NET_OK); |
| error = PTR_ERR(req->private_bio); |
| |
| /* Before we can signal completion to the upper layers, |
| * we may need to close the current transfer log epoch. |
| * We are within the request lock, so we can simply compare |
| * the request epoch number with the current transfer log |
| * epoch number. If they match, increase the current_tle_nr, |
| * and reset the transfer log epoch write_cnt. |
| */ |
| if (op_is_write(bio_op(req->master_bio)) && |
| req->epoch == atomic_read(&first_peer_device(device)->connection->current_tle_nr)) |
| start_new_tl_epoch(first_peer_device(device)->connection); |
| |
| /* Update disk stats */ |
| _drbd_end_io_acct(device, req); |
| |
| /* If READ failed, |
| * have it be pushed back to the retry work queue, |
| * so it will re-enter __drbd_make_request(), |
| * and be re-assigned to a suitable local or remote path, |
| * or failed if we do not have access to good data anymore. |
| * |
| * Unless it was failed early by __drbd_make_request(), |
| * because no path was available, in which case |
| * it was not even added to the transfer_log. |
| * |
| * read-ahead may fail, and will not be retried. |
| * |
| * WRITE should have used all available paths already. |
| */ |
| if (!ok && |
| bio_op(req->master_bio) == REQ_OP_READ && |
| !(req->master_bio->bi_opf & REQ_RAHEAD) && |
| !list_empty(&req->tl_requests)) |
| req->rq_state |= RQ_POSTPONED; |
| |
| if (!(req->rq_state & RQ_POSTPONED)) { |
| m->error = ok ? 0 : (error ?: -EIO); |
| m->bio = req->master_bio; |
| req->master_bio = NULL; |
| /* We leave it in the tree, to be able to verify later |
| * write-acks in protocol != C during resync. |
| * But we mark it as "complete", so it won't be counted as |
| * conflict in a multi-primary setup. */ |
| req->i.completed = true; |
| } |
| |
| if (req->i.waiting) |
| wake_up(&device->misc_wait); |
| |
| /* Either we are about to complete to upper layers, |
| * or we will restart this request. |
| * In either case, the request object will be destroyed soon, |
| * so better remove it from all lists. */ |
| list_del_init(&req->req_pending_master_completion); |
| } |
| |
| /* still holds resource->req_lock */ |
| static void drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put) |
| { |
| struct drbd_device *device = req->device; |
| D_ASSERT(device, m || (req->rq_state & RQ_POSTPONED)); |
| |
| if (!put) |
| return; |
| |
| if (!atomic_sub_and_test(put, &req->completion_ref)) |
| return; |
| |
| drbd_req_complete(req, m); |
| |
| /* local completion may still come in later, |
| * we need to keep the req object around. */ |
| if (req->rq_state & RQ_LOCAL_ABORTED) |
| return; |
| |
| if (req->rq_state & RQ_POSTPONED) { |
| /* don't destroy the req object just yet, |
| * but queue it for retry */ |
| drbd_restart_request(req); |
| return; |
| } |
| |
| kref_put(&req->kref, drbd_req_destroy); |
| } |
| |
| static void set_if_null_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req) |
| { |
| struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; |
| if (!connection) |
| return; |
| if (connection->req_next == NULL) |
| connection->req_next = req; |
| } |
| |
| static void advance_conn_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req) |
| { |
| struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; |
| if (!connection) |
| return; |
| if (connection->req_next != req) |
| return; |
| list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) { |
| const unsigned s = req->rq_state; |
| if (s & RQ_NET_QUEUED) |
| break; |
| } |
| if (&req->tl_requests == &connection->transfer_log) |
| req = NULL; |
| connection->req_next = req; |
| } |
| |
| static void set_if_null_req_ack_pending(struct drbd_peer_device *peer_device, struct drbd_request *req) |
| { |
| struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; |
| if (!connection) |
| return; |
| if (connection->req_ack_pending == NULL) |
| connection->req_ack_pending = req; |
| } |
| |
| static void advance_conn_req_ack_pending(struct drbd_peer_device *peer_device, struct drbd_request *req) |
| { |
| struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; |
| if (!connection) |
| return; |
| if (connection->req_ack_pending != req) |
| return; |
| list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) { |
| const unsigned s = req->rq_state; |
| if ((s & RQ_NET_SENT) && (s & RQ_NET_PENDING)) |
| break; |
| } |
| if (&req->tl_requests == &connection->transfer_log) |
| req = NULL; |
| connection->req_ack_pending = req; |
| } |
| |
| static void set_if_null_req_not_net_done(struct drbd_peer_device *peer_device, struct drbd_request *req) |
| { |
| struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; |
| if (!connection) |
| return; |
| if (connection->req_not_net_done == NULL) |
| connection->req_not_net_done = req; |
| } |
| |
| static void advance_conn_req_not_net_done(struct drbd_peer_device *peer_device, struct drbd_request *req) |
| { |
| struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; |
| if (!connection) |
| return; |
| if (connection->req_not_net_done != req) |
| return; |
| list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) { |
| const unsigned s = req->rq_state; |
| if ((s & RQ_NET_SENT) && !(s & RQ_NET_DONE)) |
| break; |
| } |
| if (&req->tl_requests == &connection->transfer_log) |
| req = NULL; |
| connection->req_not_net_done = req; |
| } |
| |
| /* I'd like this to be the only place that manipulates |
| * req->completion_ref and req->kref. */ |
| static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m, |
| int clear, int set) |
| { |
| struct drbd_device *device = req->device; |
| struct drbd_peer_device *peer_device = first_peer_device(device); |
| unsigned s = req->rq_state; |
| int c_put = 0; |
| |
| if (drbd_suspended(device) && !((s | clear) & RQ_COMPLETION_SUSP)) |
| set |= RQ_COMPLETION_SUSP; |
| |
| /* apply */ |
| |
| req->rq_state &= ~clear; |
| req->rq_state |= set; |
| |
| /* no change? */ |
| if (req->rq_state == s) |
| return; |
| |
| /* intent: get references */ |
| |
| kref_get(&req->kref); |
| |
| if (!(s & RQ_LOCAL_PENDING) && (set & RQ_LOCAL_PENDING)) |
| atomic_inc(&req->completion_ref); |
| |
| if (!(s & RQ_NET_PENDING) && (set & RQ_NET_PENDING)) { |
| inc_ap_pending(device); |
| atomic_inc(&req->completion_ref); |
| } |
| |
| if (!(s & RQ_NET_QUEUED) && (set & RQ_NET_QUEUED)) { |
| atomic_inc(&req->completion_ref); |
| set_if_null_req_next(peer_device, req); |
| } |
| |
| if (!(s & RQ_EXP_BARR_ACK) && (set & RQ_EXP_BARR_ACK)) |
| kref_get(&req->kref); /* wait for the DONE */ |
| |
| if (!(s & RQ_NET_SENT) && (set & RQ_NET_SENT)) { |
| /* potentially already completed in the ack_receiver thread */ |
| if (!(s & RQ_NET_DONE)) { |
| atomic_add(req->i.size >> 9, &device->ap_in_flight); |
| set_if_null_req_not_net_done(peer_device, req); |
| } |
| if (req->rq_state & RQ_NET_PENDING) |
| set_if_null_req_ack_pending(peer_device, req); |
| } |
| |
| if (!(s & RQ_COMPLETION_SUSP) && (set & RQ_COMPLETION_SUSP)) |
| atomic_inc(&req->completion_ref); |
| |
| /* progress: put references */ |
| |
| if ((s & RQ_COMPLETION_SUSP) && (clear & RQ_COMPLETION_SUSP)) |
| ++c_put; |
| |
| if (!(s & RQ_LOCAL_ABORTED) && (set & RQ_LOCAL_ABORTED)) { |
| D_ASSERT(device, req->rq_state & RQ_LOCAL_PENDING); |
| ++c_put; |
| } |
| |
| if ((s & RQ_LOCAL_PENDING) && (clear & RQ_LOCAL_PENDING)) { |
| if (req->rq_state & RQ_LOCAL_ABORTED) |
| kref_put(&req->kref, drbd_req_destroy); |
| else |
| ++c_put; |
| list_del_init(&req->req_pending_local); |
| } |
| |
| if ((s & RQ_NET_PENDING) && (clear & RQ_NET_PENDING)) { |
| dec_ap_pending(device); |
| ++c_put; |
| req->acked_jif = jiffies; |
| advance_conn_req_ack_pending(peer_device, req); |
| } |
| |
| if ((s & RQ_NET_QUEUED) && (clear & RQ_NET_QUEUED)) { |
| ++c_put; |
| advance_conn_req_next(peer_device, req); |
| } |
| |
| if (!(s & RQ_NET_DONE) && (set & RQ_NET_DONE)) { |
| if (s & RQ_NET_SENT) |
| atomic_sub(req->i.size >> 9, &device->ap_in_flight); |
| if (s & RQ_EXP_BARR_ACK) |
| kref_put(&req->kref, drbd_req_destroy); |
| req->net_done_jif = jiffies; |
| |
| /* in ahead/behind mode, or just in case, |
| * before we finally destroy this request, |
| * the caching pointers must not reference it anymore */ |
| advance_conn_req_next(peer_device, req); |
| advance_conn_req_ack_pending(peer_device, req); |
| advance_conn_req_not_net_done(peer_device, req); |
| } |
| |
| /* potentially complete and destroy */ |
| |
| /* If we made progress, retry conflicting peer requests, if any. */ |
| if (req->i.waiting) |
| wake_up(&device->misc_wait); |
| |
| drbd_req_put_completion_ref(req, m, c_put); |
| kref_put(&req->kref, drbd_req_destroy); |
| } |
| |
| static void drbd_report_io_error(struct drbd_device *device, struct drbd_request *req) |
| { |
| char b[BDEVNAME_SIZE]; |
| |
| if (!__ratelimit(&drbd_ratelimit_state)) |
| return; |
| |
| drbd_warn(device, "local %s IO error sector %llu+%u on %s\n", |
| (req->rq_state & RQ_WRITE) ? "WRITE" : "READ", |
| (unsigned long long)req->i.sector, |
| req->i.size >> 9, |
| bdevname(device->ldev->backing_bdev, b)); |
| } |
| |
| /* Helper for HANDED_OVER_TO_NETWORK. |
| * Is this a protocol A write (neither WRITE_ACK nor RECEIVE_ACK expected)? |
| * Is it also still "PENDING"? |
| * --> If so, clear PENDING and set NET_OK below. |
| * If it is a protocol A write, but not RQ_PENDING anymore, neg-ack was faster |
| * (and we must not set RQ_NET_OK) */ |
| static inline bool is_pending_write_protocol_A(struct drbd_request *req) |
| { |
| return (req->rq_state & |
| (RQ_WRITE|RQ_NET_PENDING|RQ_EXP_WRITE_ACK|RQ_EXP_RECEIVE_ACK)) |
| == (RQ_WRITE|RQ_NET_PENDING); |
| } |
| |
| /* 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_device *const device = req->device; |
| struct drbd_peer_device *const peer_device = first_peer_device(device); |
| struct drbd_connection *const connection = peer_device ? peer_device->connection : NULL; |
| struct net_conf *nc; |
| int p, rv = 0; |
| |
| if (m) |
| m->bio = NULL; |
| |
| switch (what) { |
| default: |
| drbd_err(device, "LOGIC BUG in %s:%u\n", __FILE__ , __LINE__); |
| break; |
| |
| /* does not happen... |
| * initialization done in drbd_req_new |
| case CREATED: |
| break; |
| */ |
| |
| case TO_BE_SENT: /* via network */ |
| /* reached via __drbd_make_request |
| * and from w_read_retry_remote */ |
| D_ASSERT(device, !(req->rq_state & RQ_NET_MASK)); |
| rcu_read_lock(); |
| nc = rcu_dereference(connection->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(device, !(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) |
| device->writ_cnt += req->i.size >> 9; |
| else |
| device->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(device, req); |
| __drbd_chk_io_error(device, 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(device, req->i.sector, req->i.size); |
| drbd_report_io_error(device, req); |
| __drbd_chk_io_error(device, DRBD_READ_ERROR); |
| /* fall through. */ |
| case READ_AHEAD_COMPLETED_WITH_ERROR: |
| /* it is legal to fail read-ahead, no __drbd_chk_io_error in that case. */ |
| mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED); |
| break; |
| |
| case DISCARD_COMPLETED_NOTSUPP: |
| case DISCARD_COMPLETED_WITH_ERROR: |
| /* I'd rather not detach from local disk just because it |
| * failed a REQ_DISCARD. */ |
| mod_rq_state(req, m, RQ_LOCAL_PENDING, RQ_LOCAL_COMPLETED); |
| break; |
| |
| case QUEUE_FOR_NET_READ: |
| /* READ, 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(device, drbd_interval_empty(&req->i)); |
| drbd_insert_interval(&device->read_requests, &req->i); |
| |
| set_bit(UNPLUG_REMOTE, &device->flags); |
| |
| D_ASSERT(device, req->rq_state & RQ_NET_PENDING); |
| D_ASSERT(device, (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(&connection->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(device, drbd_interval_empty(&req->i)); |
| drbd_insert_interval(&device->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, &device->flags); |
| |
| /* queue work item to send data */ |
| D_ASSERT(device, 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(&connection->sender_work, |
| &req->w); |
| |
| /* close the epoch, in case it outgrew the limit */ |
| rcu_read_lock(); |
| nc = rcu_dereference(connection->net_conf); |
| p = nc->max_epoch_size; |
| rcu_read_unlock(); |
| if (connection->current_tle_writes >= p) |
| start_new_tl_epoch(connection); |
| |
| 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(&connection->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 (is_pending_write_protocol_A(req)) |
| /* this is what is dangerous about protocol A: |
| * pretend it was successfully written on the peer. */ |
| mod_rq_state(req, m, RQ_NET_QUEUED|RQ_NET_PENDING, |
| RQ_NET_SENT|RQ_NET_OK); |
| else |
| mod_rq_state(req, m, RQ_NET_QUEUED, RQ_NET_SENT); |
| /* 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. */ |
| 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(device, req->rq_state & RQ_NET_PENDING); |
| D_ASSERT(device, 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: |
| /* Normal operation protocol C: successfully written on peer. |
| * During resync, even in protocol != C, |
| * we requested an explicit write ack anyways. |
| * Which means we cannot even assert anything here. |
| * 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(device, 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: |
| mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK); |
| break; |
| |
| case POSTPONE_WRITE: |
| D_ASSERT(device, 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(device, req->rq_state & RQ_NET_PENDING); |
| req->rq_state |= RQ_POSTPONED; |
| if (req->i.waiting) |
| wake_up(&device->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(device); /* always succeeds in this call path */ |
| req->w.cb = w_restart_disk_io; |
| drbd_queue_work(&connection->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->dw.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) { |
| /* w.cb expected to be w_send_dblock, or w_send_read_req */ |
| drbd_queue_work(&connection->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... */ |
| drbd_err(device, "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(device, 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(connection); |
| 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_device *device, sector_t sector, int size) |
| { |
| unsigned long sbnr, ebnr; |
| sector_t esector, nr_sectors; |
| |
| if (device->state.disk == D_UP_TO_DATE) |
| return true; |
| if (device->state.disk != D_INCONSISTENT) |
| return false; |
| esector = sector + (size >> 9) - 1; |
| nr_sectors = drbd_get_capacity(device->this_bdev); |
| D_ASSERT(device, sector < nr_sectors); |
| D_ASSERT(device, esector < nr_sectors); |
| |
| sbnr = BM_SECT_TO_BIT(sector); |
| ebnr = BM_SECT_TO_BIT(esector); |
| |
| return drbd_bm_count_bits(device, sbnr, ebnr) == 0; |
| } |
| |
| static bool remote_due_to_read_balancing(struct drbd_device *device, sector_t sector, |
| enum drbd_read_balancing rbm) |
| { |
| struct backing_dev_info *bdi; |
| int stripe_shift; |
| |
| switch (rbm) { |
| case RB_CONGESTED_REMOTE: |
| bdi = device->ldev->backing_bdev->bd_disk->queue->backing_dev_info; |
| return bdi_read_congested(bdi); |
| case RB_LEAST_PENDING: |
| return atomic_read(&device->local_cnt) > |
| atomic_read(&device->ap_pending_cnt) + atomic_read(&device->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, &device->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_device *device = req->device; |
| struct drbd_interval *i; |
| sector_t sector = req->i.sector; |
| int size = req->i.size; |
| |
| for (;;) { |
| drbd_for_each_overlap(i, &device->write_requests, sector, size) { |
| /* Ignore, if already completed to upper layers. */ |
| if (i->completed) |
| continue; |
| /* Handle the first found overlap. After the schedule |
| * we have to restart the tree walk. */ |
| break; |
| } |
| if (!i) /* if any */ |
| break; |
| |
| /* Indicate to wake up device->misc_wait on progress. */ |
| prepare_to_wait(&device->misc_wait, &wait, TASK_UNINTERRUPTIBLE); |
| i->waiting = true; |
| spin_unlock_irq(&device->resource->req_lock); |
| schedule(); |
| spin_lock_irq(&device->resource->req_lock); |
| } |
| finish_wait(&device->misc_wait, &wait); |
| } |
| |
| /* called within req_lock */ |
| static void maybe_pull_ahead(struct drbd_device *device) |
| { |
| struct drbd_connection *connection = first_peer_device(device)->connection; |
| struct net_conf *nc; |
| bool congested = false; |
| enum drbd_on_congestion on_congestion; |
| |
| rcu_read_lock(); |
| nc = rcu_dereference(connection->net_conf); |
| on_congestion = nc ? nc->on_congestion : OC_BLOCK; |
| rcu_read_unlock(); |
| if (on_congestion == OC_BLOCK || |
| connection->agreed_pro_version < 96) |
| return; |
| |
| if (on_congestion == OC_PULL_AHEAD && device->state.conn == C_AHEAD) |
| return; /* nothing to do ... */ |
| |
| /* 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 device->act_log is there. |
| */ |
| if (!get_ldev_if_state(device, D_UP_TO_DATE)) |
| return; |
| |
| if (nc->cong_fill && |
| atomic_read(&device->ap_in_flight) >= nc->cong_fill) { |
| drbd_info(device, "Congestion-fill threshold reached\n"); |
| congested = true; |
| } |
| |
| if (device->act_log->used >= nc->cong_extents) { |
| drbd_info(device, "Congestion-extents threshold reached\n"); |
| congested = true; |
| } |
| |
| if (congested) { |
| /* start a new epoch for non-mirrored writes */ |
| start_new_tl_epoch(first_peer_device(device)->connection); |
| |
| if (on_congestion == OC_PULL_AHEAD) |
| _drbd_set_state(_NS(device, conn, C_AHEAD), 0, NULL); |
| else /*nc->on_congestion == OC_DISCONNECT */ |
| _drbd_set_state(_NS(device, conn, C_DISCONNECTING), 0, NULL); |
| } |
| put_ldev(device); |
| } |
| |
| /* 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_device *device = req->device; |
| enum drbd_read_balancing rbm; |
| |
| if (req->private_bio) { |
| if (!drbd_may_do_local_read(device, |
| req->i.sector, req->i.size)) { |
| bio_put(req->private_bio); |
| req->private_bio = NULL; |
| put_ldev(device); |
| } |
| } |
| |
| if (device->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(device->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(device, req->i.sector, rbm)) { |
| if (req->private_bio) { |
| bio_put(req->private_bio); |
| req->private_bio = NULL; |
| put_ldev(device); |
| } |
| return true; |
| } |
| |
| return false; |
| } |
| |
| bool drbd_should_do_remote(union drbd_dev_state s) |
| { |
| return s.pdsk == D_UP_TO_DATE || |
| (s.pdsk >= D_INCONSISTENT && |
| s.conn >= C_WF_BITMAP_T && |
| s.conn < C_AHEAD); |
| /* Before proto 96 that was >= CONNECTED instead of >= C_WF_BITMAP_T. |
| That is equivalent since before 96 IO was frozen in the C_WF_BITMAP* |
| states. */ |
| } |
| |
| static bool drbd_should_send_out_of_sync(union drbd_dev_state s) |
| { |
| return s.conn == C_AHEAD || s.conn == C_WF_BITMAP_S; |
| /* pdsk = D_INCONSISTENT as a consequence. Protocol 96 check not necessary |
| since we enter state C_AHEAD only if proto >= 96 */ |
| } |
| |
| /* 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_device *device = req->device; |
| int remote, send_oos; |
| |
| remote = drbd_should_do_remote(device->state); |
| send_oos = drbd_should_send_out_of_sync(device->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(device, req->master_bio->bi_opf & REQ_PREFLUSH); |
| if (remote) |
| _req_mod(req, QUEUE_AS_DRBD_BARRIER); |
| return remote; |
| } |
| |
| if (!remote && !send_oos) |
| return 0; |
| |
| D_ASSERT(device, !(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(device, req->i.sector, req->i.size)) |
| _req_mod(req, QUEUE_FOR_SEND_OOS); |
| |
| return remote; |
| } |
| |
| static void drbd_process_discard_req(struct drbd_request *req) |
| { |
| struct block_device *bdev = req->device->ldev->backing_bdev; |
| |
| if (blkdev_issue_zeroout(bdev, req->i.sector, req->i.size >> 9, |
| GFP_NOIO, 0)) |
| req->private_bio->bi_status = BLK_STS_IOERR; |
| bio_endio(req->private_bio); |
| } |
| |
| static void |
| drbd_submit_req_private_bio(struct drbd_request *req) |
| { |
| struct drbd_device *device = req->device; |
| struct bio *bio = req->private_bio; |
| unsigned int type; |
| |
| if (bio_op(bio) != REQ_OP_READ) |
| type = DRBD_FAULT_DT_WR; |
| else if (bio->bi_opf & REQ_RAHEAD) |
| type = DRBD_FAULT_DT_RA; |
| else |
| type = DRBD_FAULT_DT_RD; |
| |
| bio_set_dev(bio, device->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(device)) { |
| if (drbd_insert_fault(device, type)) |
| bio_io_error(bio); |
| else if (bio_op(bio) == REQ_OP_WRITE_ZEROES || |
| bio_op(bio) == REQ_OP_DISCARD) |
| drbd_process_discard_req(req); |
| else |
| generic_make_request(bio); |
| put_ldev(device); |
| } else |
| bio_io_error(bio); |
| } |
| |
| static void drbd_queue_write(struct drbd_device *device, struct drbd_request *req) |
| { |
| spin_lock_irq(&device->resource->req_lock); |
| list_add_tail(&req->tl_requests, &device->submit.writes); |
| list_add_tail(&req->req_pending_master_completion, |
| &device->pending_master_completion[1 /* WRITE */]); |
| spin_unlock_irq(&device->resource->req_lock); |
| queue_work(device->submit.wq, &device->submit.worker); |
| /* do_submit() may sleep internally on al_wait, too */ |
| wake_up(&device->al_wait); |
| } |
| |
| /* 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. |
| */ |
| static struct drbd_request * |
| drbd_request_prepare(struct drbd_device *device, struct bio *bio, unsigned long start_jif) |
| { |
| const int rw = bio_data_dir(bio); |
| struct drbd_request *req; |
| |
| /* allocate outside of all locks; */ |
| req = drbd_req_new(device, bio); |
| if (!req) { |
| dec_ap_bio(device); |
| /* only pass the error to the upper layers. |
| * if user cannot handle io errors, that's not our business. */ |
| drbd_err(device, "could not kmalloc() req\n"); |
| bio->bi_status = BLK_STS_RESOURCE; |
| bio_endio(bio); |
| return ERR_PTR(-ENOMEM); |
| } |
| req->start_jif = start_jif; |
| |
| if (!get_ldev(device)) { |
| bio_put(req->private_bio); |
| req->private_bio = NULL; |
| } |
| |
| /* Update disk stats */ |
| _drbd_start_io_acct(device, req); |
| |
| /* process discards always from our submitter thread */ |
| if (bio_op(bio) == REQ_OP_WRITE_ZEROES || |
| bio_op(bio) == REQ_OP_DISCARD) |
| goto queue_for_submitter_thread; |
| |
| if (rw == WRITE && req->private_bio && req->i.size |
| && !test_bit(AL_SUSPENDED, &device->flags)) { |
| if (!drbd_al_begin_io_fastpath(device, &req->i)) |
| goto queue_for_submitter_thread; |
| req->rq_state |= RQ_IN_ACT_LOG; |
| req->in_actlog_jif = jiffies; |
| } |
| return req; |
| |
| queue_for_submitter_thread: |
| atomic_inc(&device->ap_actlog_cnt); |
| drbd_queue_write(device, req); |
| return NULL; |
| } |
| |
| /* Require at least one path to current data. |
| * We don't want to allow writes on C_STANDALONE D_INCONSISTENT: |
| * We would not allow to read what was written, |
| * we would not have bumped the data generation uuids, |
| * we would cause data divergence for all the wrong reasons. |
| * |
| * If we don't see at least one D_UP_TO_DATE, we will fail this request, |
| * which either returns EIO, or, if OND_SUSPEND_IO is set, suspends IO, |
| * and queues for retry later. |
| */ |
| static bool may_do_writes(struct drbd_device *device) |
| { |
| const union drbd_dev_state s = device->state; |
| return s.disk == D_UP_TO_DATE || s.pdsk == D_UP_TO_DATE; |
| } |
| |
| struct drbd_plug_cb { |
| struct blk_plug_cb cb; |
| struct drbd_request *most_recent_req; |
| /* do we need more? */ |
| }; |
| |
| static void drbd_unplug(struct blk_plug_cb *cb, bool from_schedule) |
| { |
| struct drbd_plug_cb *plug = container_of(cb, struct drbd_plug_cb, cb); |
| struct drbd_resource *resource = plug->cb.data; |
| struct drbd_request *req = plug->most_recent_req; |
| |
| kfree(cb); |
| if (!req) |
| return; |
| |
| spin_lock_irq(&resource->req_lock); |
| /* In case the sender did not process it yet, raise the flag to |
| * have it followed with P_UNPLUG_REMOTE just after. */ |
| req->rq_state |= RQ_UNPLUG; |
| /* but also queue a generic unplug */ |
| drbd_queue_unplug(req->device); |
| kref_put(&req->kref, drbd_req_destroy); |
| spin_unlock_irq(&resource->req_lock); |
| } |
| |
| static struct drbd_plug_cb* drbd_check_plugged(struct drbd_resource *resource) |
| { |
| /* A lot of text to say |
| * return (struct drbd_plug_cb*)blk_check_plugged(); */ |
| struct drbd_plug_cb *plug; |
| struct blk_plug_cb *cb = blk_check_plugged(drbd_unplug, resource, sizeof(*plug)); |
| |
| if (cb) |
| plug = container_of(cb, struct drbd_plug_cb, cb); |
| else |
| plug = NULL; |
| return plug; |
| } |
| |
| static void drbd_update_plug(struct drbd_plug_cb *plug, struct drbd_request *req) |
| { |
| struct drbd_request *tmp = plug->most_recent_req; |
| /* Will be sent to some peer. |
| * Remember to tag it with UNPLUG_REMOTE on unplug */ |
| kref_get(&req->kref); |
| plug->most_recent_req = req; |
| if (tmp) |
| kref_put(&tmp->kref, drbd_req_destroy); |
| } |
| |
| static void drbd_send_and_submit(struct drbd_device *device, struct drbd_request *req) |
| { |
| struct drbd_resource *resource = device->resource; |
| const int rw = bio_data_dir(req->master_bio); |
| struct bio_and_error m = { NULL, }; |
| bool no_remote = false; |
| bool submit_private_bio = false; |
| |
| spin_lock_irq(&resource->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(device); |
| } |
| |
| |
| if (drbd_suspended(device)) { |
| /* push back and retry: */ |
| req->rq_state |= RQ_POSTPONED; |
| if (req->private_bio) { |
| bio_put(req->private_bio); |
| req->private_bio = NULL; |
| put_ldev(device); |
| } |
| goto out; |
| } |
| |
| /* We fail READ 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(&first_peer_device(device)->connection->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) |
| first_peer_device(device)->connection->current_tle_writes++; |
| |
| list_add_tail(&req->tl_requests, &first_peer_device(device)->connection->transfer_log); |
| } |
| |
| if (rw == WRITE) { |
| if (req->private_bio && !may_do_writes(device)) { |
| bio_put(req->private_bio); |
| req->private_bio = NULL; |
| put_ldev(device); |
| goto nodata; |
| } |
| 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 (no_remote == false) { |
| struct drbd_plug_cb *plug = drbd_check_plugged(resource); |
| if (plug) |
| drbd_update_plug(plug, req); |
| } |
| |
| /* If it took the fast path in drbd_request_prepare, add it here. |
| * The slow path has added it already. */ |
| if (list_empty(&req->req_pending_master_completion)) |
| list_add_tail(&req->req_pending_master_completion, |
| &device->pending_master_completion[rw == WRITE]); |
| if (req->private_bio) { |
| /* needs to be marked within the same spinlock */ |
| req->pre_submit_jif = jiffies; |
| list_add_tail(&req->req_pending_local, |
| &device->pending_completion[rw == WRITE]); |
| _req_mod(req, TO_BE_SUBMITTED); |
| /* but we need to give up the spinlock to submit */ |
| submit_private_bio = true; |
| } else if (no_remote) { |
| nodata: |
| if (__ratelimit(&drbd_ratelimit_state)) |
| drbd_err(device, "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: |
| drbd_req_put_completion_ref(req, &m, 1); |
| spin_unlock_irq(&resource->req_lock); |
| |
| /* Even though above is a kref_put(), this is safe. |
| * As long as we still need to submit our private bio, |
| * we hold a completion ref, and the request cannot disappear. |
| * If however this request did not even have a private bio to submit |
| * (e.g. remote read), req may already be invalid now. |
| * That's why we cannot check on req->private_bio. */ |
| if (submit_private_bio) |
| drbd_submit_req_private_bio(req); |
| if (m.bio) |
| complete_master_bio(device, &m); |
| } |
| |
| void __drbd_make_request(struct drbd_device *device, struct bio *bio, unsigned long start_jif) |
| { |
| struct drbd_request *req = drbd_request_prepare(device, bio, start_jif); |
| if (IS_ERR_OR_NULL(req)) |
| return; |
| drbd_send_and_submit(device, req); |
| } |
| |
| static void submit_fast_path(struct drbd_device *device, struct list_head *incoming) |
| { |
| struct blk_plug plug; |
| struct drbd_request *req, *tmp; |
| |
| blk_start_plug(&plug); |
| 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, &device->flags)) { |
| if (!drbd_al_begin_io_fastpath(device, &req->i)) |
| continue; |
| |
| req->rq_state |= RQ_IN_ACT_LOG; |
| req->in_actlog_jif = jiffies; |
| atomic_dec(&device->ap_actlog_cnt); |
| } |
| |
| list_del_init(&req->tl_requests); |
| drbd_send_and_submit(device, req); |
| } |
| blk_finish_plug(&plug); |
| } |
| |
| static bool prepare_al_transaction_nonblock(struct drbd_device *device, |
| struct list_head *incoming, |
| struct list_head *pending, |
| struct list_head *later) |
| { |
| struct drbd_request *req; |
| int wake = 0; |
| int err; |
| |
| spin_lock_irq(&device->al_lock); |
| while ((req = list_first_entry_or_null(incoming, struct drbd_request, tl_requests))) { |
| err = drbd_al_begin_io_nonblock(device, &req->i); |
| if (err == -ENOBUFS) |
| break; |
| if (err == -EBUSY) |
| wake = 1; |
| if (err) |
| list_move_tail(&req->tl_requests, later); |
| else |
| list_move_tail(&req->tl_requests, pending); |
| } |
| spin_unlock_irq(&device->al_lock); |
| if (wake) |
| wake_up(&device->al_wait); |
| return !list_empty(pending); |
| } |
| |
| static void send_and_submit_pending(struct drbd_device *device, struct list_head *pending) |
| { |
| struct blk_plug plug; |
| struct drbd_request *req; |
| |
| blk_start_plug(&plug); |
| while ((req = list_first_entry_or_null(pending, struct drbd_request, tl_requests))) { |
| req->rq_state |= RQ_IN_ACT_LOG; |
| req->in_actlog_jif = jiffies; |
| atomic_dec(&device->ap_actlog_cnt); |
| list_del_init(&req->tl_requests); |
| drbd_send_and_submit(device, req); |
| } |
| blk_finish_plug(&plug); |
| } |
| |
| void do_submit(struct work_struct *ws) |
| { |
| struct drbd_device *device = container_of(ws, struct drbd_device, submit.worker); |
| LIST_HEAD(incoming); /* from drbd_make_request() */ |
| LIST_HEAD(pending); /* to be submitted after next AL-transaction commit */ |
| LIST_HEAD(busy); /* blocked by resync requests */ |
| |
| /* grab new incoming requests */ |
| spin_lock_irq(&device->resource->req_lock); |
| list_splice_tail_init(&device->submit.writes, &incoming); |
| spin_unlock_irq(&device->resource->req_lock); |
| |
| for (;;) { |
| DEFINE_WAIT(wait); |
| |
| /* move used-to-be-busy back to front of incoming */ |
| list_splice_init(&busy, &incoming); |
| submit_fast_path(device, &incoming); |
| if (list_empty(&incoming)) |
| break; |
| |
| for (;;) { |
| prepare_to_wait(&device->al_wait, &wait, TASK_UNINTERRUPTIBLE); |
| |
| list_splice_init(&busy, &incoming); |
| prepare_al_transaction_nonblock(device, &incoming, &pending, &busy); |
| if (!list_empty(&pending)) |
| break; |
| |
| schedule(); |
| |
| /* If all currently "hot" activity log extents are kept busy by |
| * incoming requests, we still must not totally starve new |
| * requests to "cold" extents. |
| * Something left on &incoming means there had not been |
| * enough update slots available, and the activity log |
| * has been marked as "starving". |
| * |
| * Try again now, without looking for new requests, |
| * effectively blocking all new requests until we made |
| * at least _some_ progress with what we currently have. |
| */ |
| if (!list_empty(&incoming)) |
| continue; |
| |
| /* Nothing moved to pending, but nothing left |
| * on incoming: all moved to busy! |
| * Grab new and iterate. */ |
| spin_lock_irq(&device->resource->req_lock); |
| list_splice_tail_init(&device->submit.writes, &incoming); |
| spin_unlock_irq(&device->resource->req_lock); |
| } |
| finish_wait(&device->al_wait, &wait); |
| |
| /* If the transaction was full, before all incoming requests |
| * had been processed, skip ahead to commit, and iterate |
| * without splicing in more incoming requests from upper layers. |
| * |
| * Else, if all incoming have been processed, |
| * they have become either "pending" (to be submitted after |
| * next transaction commit) or "busy" (blocked by resync). |
| * |
| * Maybe more was queued, while we prepared the transaction? |
| * Try to stuff those into this transaction as well. |
| * Be strictly non-blocking here, |
| * we already have something to commit. |
| * |
| * Commit if we don't make any more progres. |
| */ |
| |
| while (list_empty(&incoming)) { |
| 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(&device->submit.writes)) |
| break; |
| |
| spin_lock_irq(&device->resource->req_lock); |
| list_splice_tail_init(&device->submit.writes, &more_incoming); |
| spin_unlock_irq(&device->resource->req_lock); |
| |
| if (list_empty(&more_incoming)) |
| break; |
| |
| made_progress = prepare_al_transaction_nonblock(device, &more_incoming, &more_pending, &busy); |
| |
| list_splice_tail_init(&more_pending, &pending); |
| list_splice_tail_init(&more_incoming, &incoming); |
| if (!made_progress) |
| break; |
| } |
| |
| drbd_al_begin_io_commit(device); |
| send_and_submit_pending(device, &pending); |
| } |
| } |
| |
| blk_qc_t drbd_make_request(struct request_queue *q, struct bio *bio) |
| { |
| struct drbd_device *device = (struct drbd_device *) q->queuedata; |
| unsigned long start_jif; |
| |
| blk_queue_split(q, &bio); |
| |
| start_jif = jiffies; |
| |
| /* |
| * what we "blindly" assume: |
| */ |
| D_ASSERT(device, IS_ALIGNED(bio->bi_iter.bi_size, 512)); |
| |
| inc_ap_bio(device); |
| __drbd_make_request(device, bio, start_jif); |
| return BLK_QC_T_NONE; |
| } |
| |
| static bool net_timeout_reached(struct drbd_request *net_req, |
| struct drbd_connection *connection, |
| unsigned long now, unsigned long ent, |
| unsigned int ko_count, unsigned int timeout) |
| { |
| struct drbd_device *device = net_req->device; |
| |
| if (!time_after(now, net_req->pre_send_jif + ent)) |
| return false; |
| |
| if (time_in_range(now, connection->last_reconnect_jif, connection->last_reconnect_jif + ent)) |
| return false; |
| |
| if (net_req->rq_state & RQ_NET_PENDING) { |
| drbd_warn(device, "Remote failed to finish a request within %ums > ko-count (%u) * timeout (%u * 0.1s)\n", |
| jiffies_to_msecs(now - net_req->pre_send_jif), ko_count, timeout); |
| return true; |
| } |
| |
| /* We received an ACK already (or are using protocol A), |
| * but are waiting for the epoch closing barrier ack. |
| * Check if we sent the barrier already. We should not blame the peer |
| * for being unresponsive, if we did not even ask it yet. */ |
| if (net_req->epoch == connection->send.current_epoch_nr) { |
| drbd_warn(device, |
| "We did not send a P_BARRIER for %ums > ko-count (%u) * timeout (%u * 0.1s); drbd kernel thread blocked?\n", |
| jiffies_to_msecs(now - net_req->pre_send_jif), ko_count, timeout); |
| return false; |
| } |
| |
| /* Worst case: we may have been blocked for whatever reason, then |
| * suddenly are able to send a lot of requests (and epoch separating |
| * barriers) in quick succession. |
| * The timestamp of the net_req may be much too old and not correspond |
| * to the sending time of the relevant unack'ed barrier packet, so |
| * would trigger a spurious timeout. The latest barrier packet may |
| * have a too recent timestamp to trigger the timeout, potentially miss |
| * a timeout. Right now we don't have a place to conveniently store |
| * these timestamps. |
| * But in this particular situation, the application requests are still |
| * completed to upper layers, DRBD should still "feel" responsive. |
| * No need yet to kill this connection, it may still recover. |
| * If not, eventually we will have queued enough into the network for |
| * us to block. From that point of view, the timestamp of the last sent |
| * barrier packet is relevant enough. |
| */ |
| if (time_after(now, connection->send.last_sent_barrier_jif + ent)) { |
| drbd_warn(device, "Remote failed to answer a P_BARRIER (sent at %lu jif; now=%lu jif) within %ums > ko-count (%u) * timeout (%u * 0.1s)\n", |
| connection->send.last_sent_barrier_jif, now, |
| jiffies_to_msecs(now - connection->send.last_sent_barrier_jif), ko_count, timeout); |
| return true; |
| } |
| return false; |
| } |
| |
| /* A request is considered timed out, if |
| * - we have some effective timeout from the configuration, |
| * with some 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. |
| */ |
| |
| void request_timer_fn(struct timer_list *t) |
| { |
| struct drbd_device *device = from_timer(device, t, request_timer); |
| struct drbd_connection *connection = first_peer_device(device)->connection; |
| struct drbd_request *req_read, *req_write, *req_peer; /* oldest request */ |
| struct net_conf *nc; |
| unsigned long oldest_submit_jif; |
| unsigned long ent = 0, dt = 0, et, nt; /* effective timeout = ko_count * timeout */ |
| unsigned long now; |
| unsigned int ko_count = 0, timeout = 0; |
| |
| rcu_read_lock(); |
| nc = rcu_dereference(connection->net_conf); |
| if (nc && device->state.conn >= C_WF_REPORT_PARAMS) { |
| ko_count = nc->ko_count; |
| timeout = nc->timeout; |
| } |
| |
| if (get_ldev(device)) { /* implicit state.disk >= D_INCONSISTENT */ |
| dt = rcu_dereference(device->ldev->disk_conf)->disk_timeout * HZ / 10; |
| put_ldev(device); |
| } |
| rcu_read_unlock(); |
| |
| |
| ent = timeout * HZ/10 * ko_count; |
| et = min_not_zero(dt, ent); |
| |
| if (!et) |
| return; /* Recurring timer stopped */ |
| |
| now = jiffies; |
| nt = now + et; |
| |
| spin_lock_irq(&device->resource->req_lock); |
| req_read = list_first_entry_or_null(&device->pending_completion[0], struct drbd_request, req_pending_local); |
| req_write = list_first_entry_or_null(&device->pending_completion[1], struct drbd_request, req_pending_local); |
| |
| /* maybe the oldest request waiting for the peer is in fact still |
| * blocking in tcp sendmsg. That's ok, though, that's handled via the |
| * socket send timeout, requesting a ping, and bumping ko-count in |
| * we_should_drop_the_connection(). |
| */ |
| |
| /* check the oldest request we did successfully sent, |
| * but which is still waiting for an ACK. */ |
| req_peer = connection->req_ack_pending; |
| |
| /* if we don't have such request (e.g. protocoll A) |
| * check the oldest requests which is still waiting on its epoch |
| * closing barrier ack. */ |
| if (!req_peer) |
| req_peer = connection->req_not_net_done; |
| |
| /* evaluate the oldest peer request only in one timer! */ |
| if (req_peer && req_peer->device != device) |
| req_peer = NULL; |
| |
| /* do we have something to evaluate? */ |
| if (req_peer == NULL && req_write == NULL && req_read == NULL) |
| goto out; |
| |
| oldest_submit_jif = |
| (req_write && req_read) |
| ? ( time_before(req_write->pre_submit_jif, req_read->pre_submit_jif) |
| ? req_write->pre_submit_jif : req_read->pre_submit_jif ) |
| : req_write ? req_write->pre_submit_jif |
| : req_read ? req_read->pre_submit_jif : now; |
| |
| if (ent && req_peer && net_timeout_reached(req_peer, connection, now, ent, ko_count, timeout)) |
| _conn_request_state(connection, NS(conn, C_TIMEOUT), CS_VERBOSE | CS_HARD); |
| |
| if (dt && oldest_submit_jif != now && |
| time_after(now, oldest_submit_jif + dt) && |
| !time_in_range(now, device->last_reattach_jif, device->last_reattach_jif + dt)) { |
| drbd_warn(device, "Local backing device failed to meet the disk-timeout\n"); |
| __drbd_chk_io_error(device, DRBD_FORCE_DETACH); |
| } |
| |
| /* Reschedule timer for the nearest not already expired timeout. |
| * Fallback to now + min(effective network timeout, disk timeout). */ |
| ent = (ent && req_peer && time_before(now, req_peer->pre_send_jif + ent)) |
| ? req_peer->pre_send_jif + ent : now + et; |
| dt = (dt && oldest_submit_jif != now && time_before(now, oldest_submit_jif + dt)) |
| ? oldest_submit_jif + dt : now + et; |
| nt = time_before(ent, dt) ? ent : dt; |
| out: |
| spin_unlock_irq(&device->resource->req_lock); |
| mod_timer(&device->request_timer, nt); |
| } |