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1776 lines
56 KiB
1776 lines
56 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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drbd_req.c |
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This file is part of DRBD by Philipp Reisner and Lars Ellenberg. |
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Copyright (C) 2001-2008, LINBIT Information Technologies GmbH. |
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Copyright (C) 1999-2008, Philipp Reisner <[email protected]>. |
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Copyright (C) 2002-2008, Lars Ellenberg <[email protected]>. |
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*/ |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/drbd.h> |
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#include "drbd_int.h" |
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#include "drbd_req.h" |
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static bool drbd_may_do_local_read(struct drbd_device *device, sector_t sector, int size); |
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static struct drbd_request *drbd_req_new(struct drbd_device *device, struct bio *bio_src) |
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{ |
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struct drbd_request *req; |
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req = mempool_alloc(&drbd_request_mempool, GFP_NOIO); |
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if (!req) |
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return NULL; |
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memset(req, 0, sizeof(*req)); |
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drbd_req_make_private_bio(req, bio_src); |
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req->rq_state = (bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0) |
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| (bio_op(bio_src) == REQ_OP_WRITE_SAME ? RQ_WSAME : 0) |
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| (bio_op(bio_src) == REQ_OP_WRITE_ZEROES ? RQ_ZEROES : 0) |
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| (bio_op(bio_src) == REQ_OP_DISCARD ? RQ_UNMAP : 0); |
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req->device = device; |
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req->master_bio = bio_src; |
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req->epoch = 0; |
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drbd_clear_interval(&req->i); |
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req->i.sector = bio_src->bi_iter.bi_sector; |
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req->i.size = bio_src->bi_iter.bi_size; |
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req->i.local = true; |
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req->i.waiting = false; |
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INIT_LIST_HEAD(&req->tl_requests); |
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INIT_LIST_HEAD(&req->w.list); |
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INIT_LIST_HEAD(&req->req_pending_master_completion); |
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INIT_LIST_HEAD(&req->req_pending_local); |
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/* one reference to be put by __drbd_make_request */ |
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atomic_set(&req->completion_ref, 1); |
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/* one kref as long as completion_ref > 0 */ |
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kref_init(&req->kref); |
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return req; |
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} |
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static void drbd_remove_request_interval(struct rb_root *root, |
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struct drbd_request *req) |
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{ |
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struct drbd_device *device = req->device; |
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struct drbd_interval *i = &req->i; |
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drbd_remove_interval(root, i); |
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/* Wake up any processes waiting for this request to complete. */ |
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if (i->waiting) |
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wake_up(&device->misc_wait); |
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} |
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void drbd_req_destroy(struct kref *kref) |
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{ |
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struct drbd_request *req = container_of(kref, struct drbd_request, kref); |
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struct drbd_device *device = req->device; |
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const unsigned s = req->rq_state; |
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if ((req->master_bio && !(s & RQ_POSTPONED)) || |
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atomic_read(&req->completion_ref) || |
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(s & RQ_LOCAL_PENDING) || |
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((s & RQ_NET_MASK) && !(s & RQ_NET_DONE))) { |
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drbd_err(device, "drbd_req_destroy: Logic BUG rq_state = 0x%x, completion_ref = %d\n", |
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s, atomic_read(&req->completion_ref)); |
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return; |
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} |
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/* If called from mod_rq_state (expected normal case) or |
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* drbd_send_and_submit (the less likely normal path), this holds the |
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* req_lock, and req->tl_requests will typicaly be on ->transfer_log, |
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* though it may be still empty (never added to the transfer log). |
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* |
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* If called from do_retry(), we do NOT hold the req_lock, but we are |
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* still allowed to unconditionally list_del(&req->tl_requests), |
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* because it will be on a local on-stack list only. */ |
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list_del_init(&req->tl_requests); |
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/* finally remove the request from the conflict detection |
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* respective block_id verification interval tree. */ |
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if (!drbd_interval_empty(&req->i)) { |
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struct rb_root *root; |
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if (s & RQ_WRITE) |
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root = &device->write_requests; |
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else |
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root = &device->read_requests; |
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drbd_remove_request_interval(root, req); |
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} else if (s & (RQ_NET_MASK & ~RQ_NET_DONE) && req->i.size != 0) |
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drbd_err(device, "drbd_req_destroy: Logic BUG: interval empty, but: rq_state=0x%x, sect=%llu, size=%u\n", |
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s, (unsigned long long)req->i.sector, req->i.size); |
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/* if it was a write, we may have to set the corresponding |
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* bit(s) out-of-sync first. If it had a local part, we need to |
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* release the reference to the activity log. */ |
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if (s & RQ_WRITE) { |
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/* Set out-of-sync unless both OK flags are set |
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* (local only or remote failed). |
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* Other places where we set out-of-sync: |
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* READ with local io-error */ |
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/* There is a special case: |
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* we may notice late that IO was suspended, |
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* and postpone, or schedule for retry, a write, |
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* before it even was submitted or sent. |
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* In that case we do not want to touch the bitmap at all. |
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*/ |
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if ((s & (RQ_POSTPONED|RQ_LOCAL_MASK|RQ_NET_MASK)) != RQ_POSTPONED) { |
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if (!(s & RQ_NET_OK) || !(s & RQ_LOCAL_OK)) |
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drbd_set_out_of_sync(device, req->i.sector, req->i.size); |
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if ((s & RQ_NET_OK) && (s & RQ_LOCAL_OK) && (s & RQ_NET_SIS)) |
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drbd_set_in_sync(device, req->i.sector, req->i.size); |
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} |
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/* one might be tempted to move the drbd_al_complete_io |
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* to the local io completion callback drbd_request_endio. |
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* but, if this was a mirror write, we may only |
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* drbd_al_complete_io after this is RQ_NET_DONE, |
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* otherwise the extent could be dropped from the al |
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* before it has actually been written on the peer. |
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* if we crash before our peer knows about the request, |
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* but after the extent has been dropped from the al, |
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* we would forget to resync the corresponding extent. |
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*/ |
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if (s & RQ_IN_ACT_LOG) { |
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if (get_ldev_if_state(device, D_FAILED)) { |
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drbd_al_complete_io(device, &req->i); |
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put_ldev(device); |
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} else if (__ratelimit(&drbd_ratelimit_state)) { |
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drbd_warn(device, "Should have called drbd_al_complete_io(, %llu, %u), " |
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"but my Disk seems to have failed :(\n", |
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(unsigned long long) req->i.sector, req->i.size); |
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} |
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} |
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} |
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mempool_free(req, &drbd_request_mempool); |
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} |
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static void wake_all_senders(struct drbd_connection *connection) |
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{ |
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wake_up(&connection->sender_work.q_wait); |
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} |
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/* must hold resource->req_lock */ |
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void start_new_tl_epoch(struct drbd_connection *connection) |
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{ |
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/* no point closing an epoch, if it is empty, anyways. */ |
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if (connection->current_tle_writes == 0) |
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return; |
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connection->current_tle_writes = 0; |
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atomic_inc(&connection->current_tle_nr); |
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wake_all_senders(connection); |
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} |
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void complete_master_bio(struct drbd_device *device, |
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struct bio_and_error *m) |
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{ |
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m->bio->bi_status = errno_to_blk_status(m->error); |
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bio_endio(m->bio); |
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dec_ap_bio(device); |
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} |
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/* Helper for __req_mod(). |
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* Set m->bio to the master bio, if it is fit to be completed, |
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* or leave it alone (it is initialized to NULL in __req_mod), |
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* if it has already been completed, or cannot be completed yet. |
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* If m->bio is set, the error status to be returned is placed in m->error. |
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*/ |
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static |
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void drbd_req_complete(struct drbd_request *req, struct bio_and_error *m) |
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{ |
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const unsigned s = req->rq_state; |
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struct drbd_device *device = req->device; |
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int error, ok; |
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/* we must not complete the master bio, while it is |
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* still being processed by _drbd_send_zc_bio (drbd_send_dblock) |
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* not yet acknowledged by the peer |
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* not yet completed by the local io subsystem |
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* these flags may get cleared in any order by |
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* the worker, |
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* the receiver, |
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* the bio_endio completion callbacks. |
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*/ |
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if ((s & RQ_LOCAL_PENDING && !(s & RQ_LOCAL_ABORTED)) || |
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(s & RQ_NET_QUEUED) || (s & RQ_NET_PENDING) || |
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(s & RQ_COMPLETION_SUSP)) { |
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drbd_err(device, "drbd_req_complete: Logic BUG rq_state = 0x%x\n", s); |
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return; |
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} |
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if (!req->master_bio) { |
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drbd_err(device, "drbd_req_complete: Logic BUG, master_bio == NULL!\n"); |
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return; |
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} |
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/* |
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* figure out whether to report success or failure. |
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* |
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* report success when at least one of the operations succeeded. |
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* or, to put the other way, |
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* only report failure, when both operations failed. |
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* |
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* what to do about the failures is handled elsewhere. |
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* what we need to do here is just: complete the master_bio. |
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* |
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* local completion error, if any, has been stored as ERR_PTR |
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* in private_bio within drbd_request_endio. |
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*/ |
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ok = (s & RQ_LOCAL_OK) || (s & RQ_NET_OK); |
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error = PTR_ERR(req->private_bio); |
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/* Before we can signal completion to the upper layers, |
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* we may need to close the current transfer log epoch. |
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* We are within the request lock, so we can simply compare |
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* the request epoch number with the current transfer log |
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* epoch number. If they match, increase the current_tle_nr, |
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* and reset the transfer log epoch write_cnt. |
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*/ |
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if (op_is_write(bio_op(req->master_bio)) && |
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req->epoch == atomic_read(&first_peer_device(device)->connection->current_tle_nr)) |
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start_new_tl_epoch(first_peer_device(device)->connection); |
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/* Update disk stats */ |
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bio_end_io_acct(req->master_bio, req->start_jif); |
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/* If READ failed, |
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* have it be pushed back to the retry work queue, |
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* so it will re-enter __drbd_make_request(), |
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* and be re-assigned to a suitable local or remote path, |
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* or failed if we do not have access to good data anymore. |
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* |
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* Unless it was failed early by __drbd_make_request(), |
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* because no path was available, in which case |
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* it was not even added to the transfer_log. |
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* |
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* read-ahead may fail, and will not be retried. |
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* |
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* WRITE should have used all available paths already. |
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*/ |
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if (!ok && |
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bio_op(req->master_bio) == REQ_OP_READ && |
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!(req->master_bio->bi_opf & REQ_RAHEAD) && |
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!list_empty(&req->tl_requests)) |
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req->rq_state |= RQ_POSTPONED; |
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if (!(req->rq_state & RQ_POSTPONED)) { |
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m->error = ok ? 0 : (error ?: -EIO); |
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m->bio = req->master_bio; |
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req->master_bio = NULL; |
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/* We leave it in the tree, to be able to verify later |
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* write-acks in protocol != C during resync. |
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* But we mark it as "complete", so it won't be counted as |
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* conflict in a multi-primary setup. */ |
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req->i.completed = true; |
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} |
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if (req->i.waiting) |
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wake_up(&device->misc_wait); |
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/* Either we are about to complete to upper layers, |
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* or we will restart this request. |
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* In either case, the request object will be destroyed soon, |
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* so better remove it from all lists. */ |
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list_del_init(&req->req_pending_master_completion); |
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} |
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/* still holds resource->req_lock */ |
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static void drbd_req_put_completion_ref(struct drbd_request *req, struct bio_and_error *m, int put) |
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{ |
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struct drbd_device *device = req->device; |
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D_ASSERT(device, m || (req->rq_state & RQ_POSTPONED)); |
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if (!put) |
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return; |
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if (!atomic_sub_and_test(put, &req->completion_ref)) |
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return; |
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drbd_req_complete(req, m); |
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/* local completion may still come in later, |
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* we need to keep the req object around. */ |
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if (req->rq_state & RQ_LOCAL_ABORTED) |
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return; |
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if (req->rq_state & RQ_POSTPONED) { |
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/* don't destroy the req object just yet, |
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* but queue it for retry */ |
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drbd_restart_request(req); |
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return; |
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} |
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kref_put(&req->kref, drbd_req_destroy); |
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} |
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static void set_if_null_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req) |
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{ |
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struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; |
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if (!connection) |
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return; |
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if (connection->req_next == NULL) |
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connection->req_next = req; |
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} |
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static void advance_conn_req_next(struct drbd_peer_device *peer_device, struct drbd_request *req) |
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{ |
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struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; |
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if (!connection) |
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return; |
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if (connection->req_next != req) |
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return; |
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list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) { |
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const unsigned s = req->rq_state; |
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if (s & RQ_NET_QUEUED) |
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break; |
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} |
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if (&req->tl_requests == &connection->transfer_log) |
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req = NULL; |
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connection->req_next = req; |
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} |
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static void set_if_null_req_ack_pending(struct drbd_peer_device *peer_device, struct drbd_request *req) |
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{ |
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struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; |
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if (!connection) |
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return; |
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if (connection->req_ack_pending == NULL) |
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connection->req_ack_pending = req; |
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} |
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static void advance_conn_req_ack_pending(struct drbd_peer_device *peer_device, struct drbd_request *req) |
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{ |
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struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; |
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if (!connection) |
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return; |
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if (connection->req_ack_pending != req) |
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return; |
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list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) { |
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const unsigned s = req->rq_state; |
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if ((s & RQ_NET_SENT) && (s & RQ_NET_PENDING)) |
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break; |
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} |
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if (&req->tl_requests == &connection->transfer_log) |
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req = NULL; |
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connection->req_ack_pending = req; |
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} |
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static void set_if_null_req_not_net_done(struct drbd_peer_device *peer_device, struct drbd_request *req) |
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{ |
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struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; |
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if (!connection) |
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return; |
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if (connection->req_not_net_done == NULL) |
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connection->req_not_net_done = req; |
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} |
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static void advance_conn_req_not_net_done(struct drbd_peer_device *peer_device, struct drbd_request *req) |
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{ |
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struct drbd_connection *connection = peer_device ? peer_device->connection : NULL; |
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if (!connection) |
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return; |
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if (connection->req_not_net_done != req) |
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return; |
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list_for_each_entry_continue(req, &connection->transfer_log, tl_requests) { |
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const unsigned s = req->rq_state; |
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if ((s & RQ_NET_SENT) && !(s & RQ_NET_DONE)) |
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break; |
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} |
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if (&req->tl_requests == &connection->transfer_log) |
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req = NULL; |
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connection->req_not_net_done = req; |
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} |
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/* I'd like this to be the only place that manipulates |
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* req->completion_ref and req->kref. */ |
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static void mod_rq_state(struct drbd_request *req, struct bio_and_error *m, |
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int clear, int set) |
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{ |
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struct drbd_device *device = req->device; |
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struct drbd_peer_device *peer_device = first_peer_device(device); |
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unsigned s = req->rq_state; |
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int c_put = 0; |
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if (drbd_suspended(device) && !((s | clear) & RQ_COMPLETION_SUSP)) |
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set |= RQ_COMPLETION_SUSP; |
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/* apply */ |
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req->rq_state &= ~clear; |
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req->rq_state |= set; |
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|
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/* no change? */ |
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if (req->rq_state == s) |
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return; |
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|
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/* intent: get references */ |
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kref_get(&req->kref); |
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if (!(s & RQ_LOCAL_PENDING) && (set & RQ_LOCAL_PENDING)) |
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atomic_inc(&req->completion_ref); |
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if (!(s & RQ_NET_PENDING) && (set & RQ_NET_PENDING)) { |
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inc_ap_pending(device); |
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atomic_inc(&req->completion_ref); |
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} |
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if (!(s & RQ_NET_QUEUED) && (set & RQ_NET_QUEUED)) { |
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atomic_inc(&req->completion_ref); |
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set_if_null_req_next(peer_device, req); |
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} |
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|
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if (!(s & RQ_EXP_BARR_ACK) && (set & RQ_EXP_BARR_ACK)) |
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kref_get(&req->kref); /* wait for the DONE */ |
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|
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if (!(s & RQ_NET_SENT) && (set & RQ_NET_SENT)) { |
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/* potentially already completed in the ack_receiver thread */ |
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if (!(s & RQ_NET_DONE)) { |
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atomic_add(req->i.size >> 9, &device->ap_in_flight); |
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set_if_null_req_not_net_done(peer_device, req); |
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} |
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if (req->rq_state & RQ_NET_PENDING) |
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set_if_null_req_ack_pending(peer_device, req); |
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} |
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|
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if (!(s & RQ_COMPLETION_SUSP) && (set & RQ_COMPLETION_SUSP)) |
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atomic_inc(&req->completion_ref); |
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|
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/* progress: put references */ |
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|
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if ((s & RQ_COMPLETION_SUSP) && (clear & RQ_COMPLETION_SUSP)) |
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++c_put; |
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|
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if (!(s & RQ_LOCAL_ABORTED) && (set & RQ_LOCAL_ABORTED)) { |
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D_ASSERT(device, req->rq_state & RQ_LOCAL_PENDING); |
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++c_put; |
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} |
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|
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if ((s & RQ_LOCAL_PENDING) && (clear & RQ_LOCAL_PENDING)) { |
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if (req->rq_state & RQ_LOCAL_ABORTED) |
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kref_put(&req->kref, drbd_req_destroy); |
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else |
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++c_put; |
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list_del_init(&req->req_pending_local); |
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} |
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|
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if ((s & RQ_NET_PENDING) && (clear & RQ_NET_PENDING)) { |
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dec_ap_pending(device); |
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++c_put; |
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req->acked_jif = jiffies; |
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advance_conn_req_ack_pending(peer_device, req); |
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} |
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|
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if ((s & RQ_NET_QUEUED) && (clear & RQ_NET_QUEUED)) { |
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++c_put; |
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advance_conn_req_next(peer_device, req); |
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} |
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|
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if (!(s & RQ_NET_DONE) && (set & RQ_NET_DONE)) { |
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if (s & RQ_NET_SENT) |
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atomic_sub(req->i.size >> 9, &device->ap_in_flight); |
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if (s & RQ_EXP_BARR_ACK) |
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kref_put(&req->kref, drbd_req_destroy); |
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req->net_done_jif = jiffies; |
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|
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/* in ahead/behind mode, or just in case, |
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* before we finally destroy this request, |
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* the caching pointers must not reference it anymore */ |
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advance_conn_req_next(peer_device, req); |
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advance_conn_req_ack_pending(peer_device, req); |
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advance_conn_req_not_net_done(peer_device, req); |
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} |
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|
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/* potentially complete and destroy */ |
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|
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/* If we made progress, retry conflicting peer requests, if any. */ |
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if (req->i.waiting) |
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wake_up(&device->misc_wait); |
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|
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drbd_req_put_completion_ref(req, m, c_put); |
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kref_put(&req->kref, drbd_req_destroy); |
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} |
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|
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static void drbd_report_io_error(struct drbd_device *device, struct drbd_request *req) |
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{ |
|
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); |
|
fallthrough; |
|
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_OP_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; |
|
} |
|
fallthrough; /* 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 = get_capacity(device->vdisk); |
|
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_or_zeroes_req(struct drbd_request *req, int flags) |
|
{ |
|
int err = drbd_issue_discard_or_zero_out(req->device, |
|
req->i.sector, req->i.size >> 9, flags); |
|
if (err) |
|
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) |
|
drbd_process_discard_or_zeroes_req(req, EE_ZEROOUT | |
|
((bio->bi_opf & REQ_NOUNMAP) ? 0 : EE_TRIM)); |
|
else if (bio_op(bio) == REQ_OP_DISCARD) |
|
drbd_process_discard_or_zeroes_req(req, EE_TRIM); |
|
else |
|
submit_bio_noacct(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); |
|
} |
|
|
|
/* Update disk stats */ |
|
req->start_jif = bio_start_io_acct(req->master_bio); |
|
|
|
if (!get_ldev(device)) { |
|
bio_put(req->private_bio); |
|
req->private_bio = NULL; |
|
} |
|
|
|
/* 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_submit_bio(struct bio *bio) |
|
{ |
|
struct drbd_device *device = bio->bi_disk->private_data; |
|
unsigned long start_jif; |
|
|
|
blk_queue_split(&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); |
|
}
|
|
|