1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 drbd_actlog.c
4
5 This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
6
7 Copyright (C) 2003-2008, LINBIT Information Technologies GmbH.
8 Copyright (C) 2003-2008, Philipp Reisner <philipp.reisner@linbit.com>.
9 Copyright (C) 2003-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
10
11
12 */
13
14#include <linux/slab.h>
15#include <linux/crc32c.h>
16#include <linux/drbd.h>
17#include <linux/drbd_limits.h>
18#include "drbd_int.h"
19
20
21enum al_transaction_types {
22 AL_TR_UPDATE = 0,
23 AL_TR_INITIALIZED = 0xffff
24};
25/* all fields on disc in big endian */
26struct __packed al_transaction_on_disk {
27 /* don't we all like magic */
28 __be32 magic;
29
30 /* to identify the most recent transaction block
31 * in the on disk ring buffer */
32 __be32 tr_number;
33
34 /* checksum on the full 4k block, with this field set to 0. */
35 __be32 crc32c;
36
37 /* type of transaction, special transaction types like:
38 * purge-all, set-all-idle, set-all-active, ... to-be-defined
39 * see also enum al_transaction_types */
40 __be16 transaction_type;
41
42 /* we currently allow only a few thousand extents,
43 * so 16bit will be enough for the slot number. */
44
45 /* how many updates in this transaction */
46 __be16 n_updates;
47
48 /* maximum slot number, "al-extents" in drbd.conf speak.
49 * Having this in each transaction should make reconfiguration
50 * of that parameter easier. */
51 __be16 context_size;
52
53 /* slot number the context starts with */
54 __be16 context_start_slot_nr;
55
56 /* Some reserved bytes. Expected usage is a 64bit counter of
57 * sectors-written since device creation, and other data generation tag
58 * supporting usage */
59 __be32 __reserved[4];
60
61 /* --- 36 byte used --- */
62
63 /* Reserve space for up to AL_UPDATES_PER_TRANSACTION changes
64 * in one transaction, then use the remaining byte in the 4k block for
65 * context information. "Flexible" number of updates per transaction
66 * does not help, as we have to account for the case when all update
67 * slots are used anyways, so it would only complicate code without
68 * additional benefit.
69 */
70 __be16 update_slot_nr[AL_UPDATES_PER_TRANSACTION];
71
72 /* but the extent number is 32bit, which at an extent size of 4 MiB
73 * allows to cover device sizes of up to 2**54 Byte (16 PiB) */
74 __be32 update_extent_nr[AL_UPDATES_PER_TRANSACTION];
75
76 /* --- 420 bytes used (36 + 64*6) --- */
77
78 /* 4096 - 420 = 3676 = 919 * 4 */
79 __be32 context[AL_CONTEXT_PER_TRANSACTION];
80};
81
82void *drbd_md_get_buffer(struct drbd_device *device, const char *intent)
83{
84 int r;
85
86 wait_event(device->misc_wait,
87 (r = atomic_cmpxchg(&device->md_io.in_use, 0, 1)) == 0 ||
88 device->state.disk <= D_FAILED);
89
90 if (r)
91 return NULL;
92
93 device->md_io.current_use = intent;
94 device->md_io.start_jif = jiffies;
95 device->md_io.submit_jif = device->md_io.start_jif - 1;
96 return page_address(device->md_io.page);
97}
98
99void drbd_md_put_buffer(struct drbd_device *device)
100{
101 if (atomic_dec_and_test(v: &device->md_io.in_use))
102 wake_up(&device->misc_wait);
103}
104
105void wait_until_done_or_force_detached(struct drbd_device *device, struct drbd_backing_dev *bdev,
106 unsigned int *done)
107{
108 long dt;
109
110 rcu_read_lock();
111 dt = rcu_dereference(bdev->disk_conf)->disk_timeout;
112 rcu_read_unlock();
113 dt = dt * HZ / 10;
114 if (dt == 0)
115 dt = MAX_SCHEDULE_TIMEOUT;
116
117 dt = wait_event_timeout(device->misc_wait,
118 *done || test_bit(FORCE_DETACH, &device->flags), dt);
119 if (dt == 0) {
120 drbd_err(device, "meta-data IO operation timed out\n");
121 drbd_chk_io_error(device, 1, DRBD_FORCE_DETACH);
122 }
123}
124
125static int _drbd_md_sync_page_io(struct drbd_device *device,
126 struct drbd_backing_dev *bdev,
127 sector_t sector, enum req_op op)
128{
129 struct bio *bio;
130 /* we do all our meta data IO in aligned 4k blocks. */
131 const int size = 4096;
132 int err;
133 blk_opf_t op_flags = 0;
134
135 device->md_io.done = 0;
136 device->md_io.error = -ENODEV;
137
138 if ((op == REQ_OP_WRITE) && !test_bit(MD_NO_FUA, &device->flags))
139 op_flags |= REQ_FUA | REQ_PREFLUSH;
140 op_flags |= REQ_SYNC;
141
142 bio = bio_alloc_bioset(bdev: bdev->md_bdev, nr_vecs: 1, opf: op | op_flags, GFP_NOIO,
143 bs: &drbd_md_io_bio_set);
144 bio->bi_iter.bi_sector = sector;
145 err = -EIO;
146 if (bio_add_page(bio, page: device->md_io.page, len: size, off: 0) != size)
147 goto out;
148 bio->bi_private = device;
149 bio->bi_end_io = drbd_md_endio;
150
151 if (op != REQ_OP_WRITE && device->state.disk == D_DISKLESS && device->ldev == NULL)
152 /* special case, drbd_md_read() during drbd_adm_attach(): no get_ldev */
153 ;
154 else if (!get_ldev_if_state(device, D_ATTACHING)) {
155 /* Corresponding put_ldev in drbd_md_endio() */
156 drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in _drbd_md_sync_page_io()\n");
157 err = -ENODEV;
158 goto out;
159 }
160
161 bio_get(bio); /* one bio_put() is in the completion handler */
162 atomic_inc(v: &device->md_io.in_use); /* drbd_md_put_buffer() is in the completion handler */
163 device->md_io.submit_jif = jiffies;
164 if (drbd_insert_fault(device, type: (op == REQ_OP_WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD))
165 bio_io_error(bio);
166 else
167 submit_bio(bio);
168 wait_until_done_or_force_detached(device, bdev, done: &device->md_io.done);
169 if (!bio->bi_status)
170 err = device->md_io.error;
171
172 out:
173 bio_put(bio);
174 return err;
175}
176
177int drbd_md_sync_page_io(struct drbd_device *device, struct drbd_backing_dev *bdev,
178 sector_t sector, enum req_op op)
179{
180 int err;
181 D_ASSERT(device, atomic_read(&device->md_io.in_use) == 1);
182
183 BUG_ON(!bdev->md_bdev);
184
185 dynamic_drbd_dbg(device, "meta_data io: %s [%d]:%s(,%llus,%s) %pS\n",
186 current->comm, current->pid, __func__,
187 (unsigned long long)sector, (op == REQ_OP_WRITE) ? "WRITE" : "READ",
188 (void*)_RET_IP_ );
189
190 if (sector < drbd_md_first_sector(bdev) ||
191 sector + 7 > drbd_md_last_sector(bdev))
192 drbd_alert(device, "%s [%d]:%s(,%llus,%s) out of range md access!\n",
193 current->comm, current->pid, __func__,
194 (unsigned long long)sector,
195 (op == REQ_OP_WRITE) ? "WRITE" : "READ");
196
197 err = _drbd_md_sync_page_io(device, bdev, sector, op);
198 if (err) {
199 drbd_err(device, "drbd_md_sync_page_io(,%llus,%s) failed with error %d\n",
200 (unsigned long long)sector,
201 (op == REQ_OP_WRITE) ? "WRITE" : "READ", err);
202 }
203 return err;
204}
205
206static struct bm_extent *find_active_resync_extent(struct drbd_device *device, unsigned int enr)
207{
208 struct lc_element *tmp;
209 tmp = lc_find(lc: device->resync, enr: enr/AL_EXT_PER_BM_SECT);
210 if (unlikely(tmp != NULL)) {
211 struct bm_extent *bm_ext = lc_entry(tmp, struct bm_extent, lce);
212 if (test_bit(BME_NO_WRITES, &bm_ext->flags))
213 return bm_ext;
214 }
215 return NULL;
216}
217
218static struct lc_element *_al_get(struct drbd_device *device, unsigned int enr, bool nonblock)
219{
220 struct lc_element *al_ext;
221 struct bm_extent *bm_ext;
222 int wake;
223
224 spin_lock_irq(lock: &device->al_lock);
225 bm_ext = find_active_resync_extent(device, enr);
226 if (bm_ext) {
227 wake = !test_and_set_bit(BME_PRIORITY, addr: &bm_ext->flags);
228 spin_unlock_irq(lock: &device->al_lock);
229 if (wake)
230 wake_up(&device->al_wait);
231 return NULL;
232 }
233 if (nonblock)
234 al_ext = lc_try_get(lc: device->act_log, enr);
235 else
236 al_ext = lc_get(lc: device->act_log, enr);
237 spin_unlock_irq(lock: &device->al_lock);
238 return al_ext;
239}
240
241bool drbd_al_begin_io_fastpath(struct drbd_device *device, struct drbd_interval *i)
242{
243 /* for bios crossing activity log extent boundaries,
244 * we may need to activate two extents in one go */
245 unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
246 unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
247
248 D_ASSERT(device, first <= last);
249 D_ASSERT(device, atomic_read(&device->local_cnt) > 0);
250
251 /* FIXME figure out a fast path for bios crossing AL extent boundaries */
252 if (first != last)
253 return false;
254
255 return _al_get(device, enr: first, nonblock: true);
256}
257
258bool drbd_al_begin_io_prepare(struct drbd_device *device, struct drbd_interval *i)
259{
260 /* for bios crossing activity log extent boundaries,
261 * we may need to activate two extents in one go */
262 unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
263 unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
264 unsigned enr;
265 bool need_transaction = false;
266
267 D_ASSERT(device, first <= last);
268 D_ASSERT(device, atomic_read(&device->local_cnt) > 0);
269
270 for (enr = first; enr <= last; enr++) {
271 struct lc_element *al_ext;
272 wait_event(device->al_wait,
273 (al_ext = _al_get(device, enr, false)) != NULL);
274 if (al_ext->lc_number != enr)
275 need_transaction = true;
276 }
277 return need_transaction;
278}
279
280#if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)
281/* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT
282 * are still coupled, or assume too much about their relation.
283 * Code below will not work if this is violated.
284 * Will be cleaned up with some followup patch.
285 */
286# error FIXME
287#endif
288
289static unsigned int al_extent_to_bm_page(unsigned int al_enr)
290{
291 return al_enr >>
292 /* bit to page */
293 ((PAGE_SHIFT + 3) -
294 /* al extent number to bit */
295 (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT));
296}
297
298static sector_t al_tr_number_to_on_disk_sector(struct drbd_device *device)
299{
300 const unsigned int stripes = device->ldev->md.al_stripes;
301 const unsigned int stripe_size_4kB = device->ldev->md.al_stripe_size_4k;
302
303 /* transaction number, modulo on-disk ring buffer wrap around */
304 unsigned int t = device->al_tr_number % (device->ldev->md.al_size_4k);
305
306 /* ... to aligned 4k on disk block */
307 t = ((t % stripes) * stripe_size_4kB) + t/stripes;
308
309 /* ... to 512 byte sector in activity log */
310 t *= 8;
311
312 /* ... plus offset to the on disk position */
313 return device->ldev->md.md_offset + device->ldev->md.al_offset + t;
314}
315
316static int __al_write_transaction(struct drbd_device *device, struct al_transaction_on_disk *buffer)
317{
318 struct lc_element *e;
319 sector_t sector;
320 int i, mx;
321 unsigned extent_nr;
322 unsigned crc = 0;
323 int err = 0;
324
325 memset(buffer, 0, sizeof(*buffer));
326 buffer->magic = cpu_to_be32(DRBD_AL_MAGIC);
327 buffer->tr_number = cpu_to_be32(device->al_tr_number);
328
329 i = 0;
330
331 drbd_bm_reset_al_hints(device);
332
333 /* Even though no one can start to change this list
334 * once we set the LC_LOCKED -- from drbd_al_begin_io(),
335 * lc_try_lock_for_transaction() --, someone may still
336 * be in the process of changing it. */
337 spin_lock_irq(lock: &device->al_lock);
338 list_for_each_entry(e, &device->act_log->to_be_changed, list) {
339 if (i == AL_UPDATES_PER_TRANSACTION) {
340 i++;
341 break;
342 }
343 buffer->update_slot_nr[i] = cpu_to_be16(e->lc_index);
344 buffer->update_extent_nr[i] = cpu_to_be32(e->lc_new_number);
345 if (e->lc_number != LC_FREE)
346 drbd_bm_mark_for_writeout(device,
347 page_nr: al_extent_to_bm_page(al_enr: e->lc_number));
348 i++;
349 }
350 spin_unlock_irq(lock: &device->al_lock);
351 BUG_ON(i > AL_UPDATES_PER_TRANSACTION);
352
353 buffer->n_updates = cpu_to_be16(i);
354 for ( ; i < AL_UPDATES_PER_TRANSACTION; i++) {
355 buffer->update_slot_nr[i] = cpu_to_be16(-1);
356 buffer->update_extent_nr[i] = cpu_to_be32(LC_FREE);
357 }
358
359 buffer->context_size = cpu_to_be16(device->act_log->nr_elements);
360 buffer->context_start_slot_nr = cpu_to_be16(device->al_tr_cycle);
361
362 mx = min_t(int, AL_CONTEXT_PER_TRANSACTION,
363 device->act_log->nr_elements - device->al_tr_cycle);
364 for (i = 0; i < mx; i++) {
365 unsigned idx = device->al_tr_cycle + i;
366 extent_nr = lc_element_by_index(lc: device->act_log, i: idx)->lc_number;
367 buffer->context[i] = cpu_to_be32(extent_nr);
368 }
369 for (; i < AL_CONTEXT_PER_TRANSACTION; i++)
370 buffer->context[i] = cpu_to_be32(LC_FREE);
371
372 device->al_tr_cycle += AL_CONTEXT_PER_TRANSACTION;
373 if (device->al_tr_cycle >= device->act_log->nr_elements)
374 device->al_tr_cycle = 0;
375
376 sector = al_tr_number_to_on_disk_sector(device);
377
378 crc = crc32c(crc: 0, p: buffer, len: 4096);
379 buffer->crc32c = cpu_to_be32(crc);
380
381 if (drbd_bm_write_hinted(device))
382 err = -EIO;
383 else {
384 bool write_al_updates;
385 rcu_read_lock();
386 write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
387 rcu_read_unlock();
388 if (write_al_updates) {
389 if (drbd_md_sync_page_io(device, bdev: device->ldev, sector, op: REQ_OP_WRITE)) {
390 err = -EIO;
391 drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR);
392 } else {
393 device->al_tr_number++;
394 device->al_writ_cnt++;
395 }
396 }
397 }
398
399 return err;
400}
401
402static int al_write_transaction(struct drbd_device *device)
403{
404 struct al_transaction_on_disk *buffer;
405 int err;
406
407 if (!get_ldev(device)) {
408 drbd_err(device, "disk is %s, cannot start al transaction\n",
409 drbd_disk_str(device->state.disk));
410 return -EIO;
411 }
412
413 /* The bitmap write may have failed, causing a state change. */
414 if (device->state.disk < D_INCONSISTENT) {
415 drbd_err(device,
416 "disk is %s, cannot write al transaction\n",
417 drbd_disk_str(device->state.disk));
418 put_ldev(device);
419 return -EIO;
420 }
421
422 /* protects md_io_buffer, al_tr_cycle, ... */
423 buffer = drbd_md_get_buffer(device, intent: __func__);
424 if (!buffer) {
425 drbd_err(device, "disk failed while waiting for md_io buffer\n");
426 put_ldev(device);
427 return -ENODEV;
428 }
429
430 err = __al_write_transaction(device, buffer);
431
432 drbd_md_put_buffer(device);
433 put_ldev(device);
434
435 return err;
436}
437
438
439void drbd_al_begin_io_commit(struct drbd_device *device)
440{
441 bool locked = false;
442
443 /* Serialize multiple transactions.
444 * This uses test_and_set_bit, memory barrier is implicit.
445 */
446 wait_event(device->al_wait,
447 device->act_log->pending_changes == 0 ||
448 (locked = lc_try_lock_for_transaction(device->act_log)));
449
450 if (locked) {
451 /* Double check: it may have been committed by someone else,
452 * while we have been waiting for the lock. */
453 if (device->act_log->pending_changes) {
454 bool write_al_updates;
455
456 rcu_read_lock();
457 write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
458 rcu_read_unlock();
459
460 if (write_al_updates)
461 al_write_transaction(device);
462 spin_lock_irq(lock: &device->al_lock);
463 /* FIXME
464 if (err)
465 we need an "lc_cancel" here;
466 */
467 lc_committed(lc: device->act_log);
468 spin_unlock_irq(lock: &device->al_lock);
469 }
470 lc_unlock(lc: device->act_log);
471 wake_up(&device->al_wait);
472 }
473}
474
475/*
476 * @delegate: delegate activity log I/O to the worker thread
477 */
478void drbd_al_begin_io(struct drbd_device *device, struct drbd_interval *i)
479{
480 if (drbd_al_begin_io_prepare(device, i))
481 drbd_al_begin_io_commit(device);
482}
483
484int drbd_al_begin_io_nonblock(struct drbd_device *device, struct drbd_interval *i)
485{
486 struct lru_cache *al = device->act_log;
487 /* for bios crossing activity log extent boundaries,
488 * we may need to activate two extents in one go */
489 unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
490 unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
491 unsigned nr_al_extents;
492 unsigned available_update_slots;
493 unsigned enr;
494
495 D_ASSERT(device, first <= last);
496
497 nr_al_extents = 1 + last - first; /* worst case: all touched extends are cold. */
498 available_update_slots = min(al->nr_elements - al->used,
499 al->max_pending_changes - al->pending_changes);
500
501 /* We want all necessary updates for a given request within the same transaction
502 * We could first check how many updates are *actually* needed,
503 * and use that instead of the worst-case nr_al_extents */
504 if (available_update_slots < nr_al_extents) {
505 /* Too many activity log extents are currently "hot".
506 *
507 * If we have accumulated pending changes already,
508 * we made progress.
509 *
510 * If we cannot get even a single pending change through,
511 * stop the fast path until we made some progress,
512 * or requests to "cold" extents could be starved. */
513 if (!al->pending_changes)
514 __set_bit(__LC_STARVING, &device->act_log->flags);
515 return -ENOBUFS;
516 }
517
518 /* Is resync active in this area? */
519 for (enr = first; enr <= last; enr++) {
520 struct lc_element *tmp;
521 tmp = lc_find(lc: device->resync, enr: enr/AL_EXT_PER_BM_SECT);
522 if (unlikely(tmp != NULL)) {
523 struct bm_extent *bm_ext = lc_entry(tmp, struct bm_extent, lce);
524 if (test_bit(BME_NO_WRITES, &bm_ext->flags)) {
525 if (!test_and_set_bit(BME_PRIORITY, addr: &bm_ext->flags))
526 return -EBUSY;
527 return -EWOULDBLOCK;
528 }
529 }
530 }
531
532 /* Checkout the refcounts.
533 * Given that we checked for available elements and update slots above,
534 * this has to be successful. */
535 for (enr = first; enr <= last; enr++) {
536 struct lc_element *al_ext;
537 al_ext = lc_get_cumulative(lc: device->act_log, enr);
538 if (!al_ext)
539 drbd_info(device, "LOGIC BUG for enr=%u\n", enr);
540 }
541 return 0;
542}
543
544void drbd_al_complete_io(struct drbd_device *device, struct drbd_interval *i)
545{
546 /* for bios crossing activity log extent boundaries,
547 * we may need to activate two extents in one go */
548 unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
549 unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
550 unsigned enr;
551 struct lc_element *extent;
552 unsigned long flags;
553
554 D_ASSERT(device, first <= last);
555 spin_lock_irqsave(&device->al_lock, flags);
556
557 for (enr = first; enr <= last; enr++) {
558 extent = lc_find(lc: device->act_log, enr);
559 if (!extent) {
560 drbd_err(device, "al_complete_io() called on inactive extent %u\n", enr);
561 continue;
562 }
563 lc_put(lc: device->act_log, e: extent);
564 }
565 spin_unlock_irqrestore(lock: &device->al_lock, flags);
566 wake_up(&device->al_wait);
567}
568
569static int _try_lc_del(struct drbd_device *device, struct lc_element *al_ext)
570{
571 int rv;
572
573 spin_lock_irq(lock: &device->al_lock);
574 rv = (al_ext->refcnt == 0);
575 if (likely(rv))
576 lc_del(lc: device->act_log, element: al_ext);
577 spin_unlock_irq(lock: &device->al_lock);
578
579 return rv;
580}
581
582/**
583 * drbd_al_shrink() - Removes all active extents form the activity log
584 * @device: DRBD device.
585 *
586 * Removes all active extents form the activity log, waiting until
587 * the reference count of each entry dropped to 0 first, of course.
588 *
589 * You need to lock device->act_log with lc_try_lock() / lc_unlock()
590 */
591void drbd_al_shrink(struct drbd_device *device)
592{
593 struct lc_element *al_ext;
594 int i;
595
596 D_ASSERT(device, test_bit(__LC_LOCKED, &device->act_log->flags));
597
598 for (i = 0; i < device->act_log->nr_elements; i++) {
599 al_ext = lc_element_by_index(lc: device->act_log, i);
600 if (al_ext->lc_number == LC_FREE)
601 continue;
602 wait_event(device->al_wait, _try_lc_del(device, al_ext));
603 }
604
605 wake_up(&device->al_wait);
606}
607
608int drbd_al_initialize(struct drbd_device *device, void *buffer)
609{
610 struct al_transaction_on_disk *al = buffer;
611 struct drbd_md *md = &device->ldev->md;
612 int al_size_4k = md->al_stripes * md->al_stripe_size_4k;
613 int i;
614
615 __al_write_transaction(device, buffer: al);
616 /* There may or may not have been a pending transaction. */
617 spin_lock_irq(lock: &device->al_lock);
618 lc_committed(lc: device->act_log);
619 spin_unlock_irq(lock: &device->al_lock);
620
621 /* The rest of the transactions will have an empty "updates" list, and
622 * are written out only to provide the context, and to initialize the
623 * on-disk ring buffer. */
624 for (i = 1; i < al_size_4k; i++) {
625 int err = __al_write_transaction(device, buffer: al);
626 if (err)
627 return err;
628 }
629 return 0;
630}
631
632static const char *drbd_change_sync_fname[] = {
633 [RECORD_RS_FAILED] = "drbd_rs_failed_io",
634 [SET_IN_SYNC] = "drbd_set_in_sync",
635 [SET_OUT_OF_SYNC] = "drbd_set_out_of_sync"
636};
637
638/* ATTENTION. The AL's extents are 4MB each, while the extents in the
639 * resync LRU-cache are 16MB each.
640 * The caller of this function has to hold an get_ldev() reference.
641 *
642 * Adjusts the caching members ->rs_left (success) or ->rs_failed (!success),
643 * potentially pulling in (and recounting the corresponding bits)
644 * this resync extent into the resync extent lru cache.
645 *
646 * Returns whether all bits have been cleared for this resync extent,
647 * precisely: (rs_left <= rs_failed)
648 *
649 * TODO will be obsoleted once we have a caching lru of the on disk bitmap
650 */
651static bool update_rs_extent(struct drbd_device *device,
652 unsigned int enr, int count,
653 enum update_sync_bits_mode mode)
654{
655 struct lc_element *e;
656
657 D_ASSERT(device, atomic_read(&device->local_cnt));
658
659 /* When setting out-of-sync bits,
660 * we don't need it cached (lc_find).
661 * But if it is present in the cache,
662 * we should update the cached bit count.
663 * Otherwise, that extent should be in the resync extent lru cache
664 * already -- or we want to pull it in if necessary -- (lc_get),
665 * then update and check rs_left and rs_failed. */
666 if (mode == SET_OUT_OF_SYNC)
667 e = lc_find(lc: device->resync, enr);
668 else
669 e = lc_get(lc: device->resync, enr);
670 if (e) {
671 struct bm_extent *ext = lc_entry(e, struct bm_extent, lce);
672 if (ext->lce.lc_number == enr) {
673 if (mode == SET_IN_SYNC)
674 ext->rs_left -= count;
675 else if (mode == SET_OUT_OF_SYNC)
676 ext->rs_left += count;
677 else
678 ext->rs_failed += count;
679 if (ext->rs_left < ext->rs_failed) {
680 drbd_warn(device, "BAD! enr=%u rs_left=%d "
681 "rs_failed=%d count=%d cstate=%s\n",
682 ext->lce.lc_number, ext->rs_left,
683 ext->rs_failed, count,
684 drbd_conn_str(device->state.conn));
685
686 /* We don't expect to be able to clear more bits
687 * than have been set when we originally counted
688 * the set bits to cache that value in ext->rs_left.
689 * Whatever the reason (disconnect during resync,
690 * delayed local completion of an application write),
691 * try to fix it up by recounting here. */
692 ext->rs_left = drbd_bm_e_weight(device, enr);
693 }
694 } else {
695 /* Normally this element should be in the cache,
696 * since drbd_rs_begin_io() pulled it already in.
697 *
698 * But maybe an application write finished, and we set
699 * something outside the resync lru_cache in sync.
700 */
701 int rs_left = drbd_bm_e_weight(device, enr);
702 if (ext->flags != 0) {
703 drbd_warn(device, "changing resync lce: %d[%u;%02lx]"
704 " -> %d[%u;00]\n",
705 ext->lce.lc_number, ext->rs_left,
706 ext->flags, enr, rs_left);
707 ext->flags = 0;
708 }
709 if (ext->rs_failed) {
710 drbd_warn(device, "Kicking resync_lru element enr=%u "
711 "out with rs_failed=%d\n",
712 ext->lce.lc_number, ext->rs_failed);
713 }
714 ext->rs_left = rs_left;
715 ext->rs_failed = (mode == RECORD_RS_FAILED) ? count : 0;
716 /* we don't keep a persistent log of the resync lru,
717 * we can commit any change right away. */
718 lc_committed(lc: device->resync);
719 }
720 if (mode != SET_OUT_OF_SYNC)
721 lc_put(lc: device->resync, e: &ext->lce);
722 /* no race, we are within the al_lock! */
723
724 if (ext->rs_left <= ext->rs_failed) {
725 ext->rs_failed = 0;
726 return true;
727 }
728 } else if (mode != SET_OUT_OF_SYNC) {
729 /* be quiet if lc_find() did not find it. */
730 drbd_err(device, "lc_get() failed! locked=%d/%d flags=%lu\n",
731 device->resync_locked,
732 device->resync->nr_elements,
733 device->resync->flags);
734 }
735 return false;
736}
737
738void drbd_advance_rs_marks(struct drbd_peer_device *peer_device, unsigned long still_to_go)
739{
740 struct drbd_device *device = peer_device->device;
741 unsigned long now = jiffies;
742 unsigned long last = device->rs_mark_time[device->rs_last_mark];
743 int next = (device->rs_last_mark + 1) % DRBD_SYNC_MARKS;
744 if (time_after_eq(now, last + DRBD_SYNC_MARK_STEP)) {
745 if (device->rs_mark_left[device->rs_last_mark] != still_to_go &&
746 device->state.conn != C_PAUSED_SYNC_T &&
747 device->state.conn != C_PAUSED_SYNC_S) {
748 device->rs_mark_time[next] = now;
749 device->rs_mark_left[next] = still_to_go;
750 device->rs_last_mark = next;
751 }
752 }
753}
754
755/* It is called lazy update, so don't do write-out too often. */
756static bool lazy_bitmap_update_due(struct drbd_device *device)
757{
758 return time_after(jiffies, device->rs_last_bcast + 2*HZ);
759}
760
761static void maybe_schedule_on_disk_bitmap_update(struct drbd_device *device, bool rs_done)
762{
763 if (rs_done) {
764 struct drbd_connection *connection = first_peer_device(device)->connection;
765 if (connection->agreed_pro_version <= 95 ||
766 is_sync_target_state(connection_state: device->state.conn))
767 set_bit(nr: RS_DONE, addr: &device->flags);
768 /* and also set RS_PROGRESS below */
769
770 /* Else: rather wait for explicit notification via receive_state,
771 * to avoid uuids-rotated-too-fast causing full resync
772 * in next handshake, in case the replication link breaks
773 * at the most unfortunate time... */
774 } else if (!lazy_bitmap_update_due(device))
775 return;
776
777 drbd_device_post_work(device, work_bit: RS_PROGRESS);
778}
779
780static int update_sync_bits(struct drbd_device *device,
781 unsigned long sbnr, unsigned long ebnr,
782 enum update_sync_bits_mode mode)
783{
784 /*
785 * We keep a count of set bits per resync-extent in the ->rs_left
786 * caching member, so we need to loop and work within the resync extent
787 * alignment. Typically this loop will execute exactly once.
788 */
789 unsigned long flags;
790 unsigned long count = 0;
791 unsigned int cleared = 0;
792 while (sbnr <= ebnr) {
793 /* set temporary boundary bit number to last bit number within
794 * the resync extent of the current start bit number,
795 * but cap at provided end bit number */
796 unsigned long tbnr = min(ebnr, sbnr | BM_BLOCKS_PER_BM_EXT_MASK);
797 unsigned long c;
798
799 if (mode == RECORD_RS_FAILED)
800 /* Only called from drbd_rs_failed_io(), bits
801 * supposedly still set. Recount, maybe some
802 * of the bits have been successfully cleared
803 * by application IO meanwhile.
804 */
805 c = drbd_bm_count_bits(device, s: sbnr, e: tbnr);
806 else if (mode == SET_IN_SYNC)
807 c = drbd_bm_clear_bits(device, s: sbnr, e: tbnr);
808 else /* if (mode == SET_OUT_OF_SYNC) */
809 c = drbd_bm_set_bits(device, s: sbnr, e: tbnr);
810
811 if (c) {
812 spin_lock_irqsave(&device->al_lock, flags);
813 cleared += update_rs_extent(device, BM_BIT_TO_EXT(sbnr), count: c, mode);
814 spin_unlock_irqrestore(lock: &device->al_lock, flags);
815 count += c;
816 }
817 sbnr = tbnr + 1;
818 }
819 if (count) {
820 if (mode == SET_IN_SYNC) {
821 unsigned long still_to_go = drbd_bm_total_weight(device);
822 bool rs_is_done = (still_to_go <= device->rs_failed);
823 drbd_advance_rs_marks(peer_device: first_peer_device(device), still_to_go);
824 if (cleared || rs_is_done)
825 maybe_schedule_on_disk_bitmap_update(device, rs_done: rs_is_done);
826 } else if (mode == RECORD_RS_FAILED)
827 device->rs_failed += count;
828 wake_up(&device->al_wait);
829 }
830 return count;
831}
832
833static bool plausible_request_size(int size)
834{
835 return size > 0
836 && size <= DRBD_MAX_BATCH_BIO_SIZE
837 && IS_ALIGNED(size, 512);
838}
839
840/* clear the bit corresponding to the piece of storage in question:
841 * size byte of data starting from sector. Only clear bits of the affected
842 * one or more _aligned_ BM_BLOCK_SIZE blocks.
843 *
844 * called by worker on C_SYNC_TARGET and receiver on SyncSource.
845 *
846 */
847int __drbd_change_sync(struct drbd_peer_device *peer_device, sector_t sector, int size,
848 enum update_sync_bits_mode mode)
849{
850 /* Is called from worker and receiver context _only_ */
851 struct drbd_device *device = peer_device->device;
852 unsigned long sbnr, ebnr, lbnr;
853 unsigned long count = 0;
854 sector_t esector, nr_sectors;
855
856 /* This would be an empty REQ_PREFLUSH, be silent. */
857 if ((mode == SET_OUT_OF_SYNC) && size == 0)
858 return 0;
859
860 if (!plausible_request_size(size)) {
861 drbd_err(device, "%s: sector=%llus size=%d nonsense!\n",
862 drbd_change_sync_fname[mode],
863 (unsigned long long)sector, size);
864 return 0;
865 }
866
867 if (!get_ldev(device))
868 return 0; /* no disk, no metadata, no bitmap to manipulate bits in */
869
870 nr_sectors = get_capacity(disk: device->vdisk);
871 esector = sector + (size >> 9) - 1;
872
873 if (!expect(device, sector < nr_sectors))
874 goto out;
875 if (!expect(device, esector < nr_sectors))
876 esector = nr_sectors - 1;
877
878 lbnr = BM_SECT_TO_BIT(nr_sectors-1);
879
880 if (mode == SET_IN_SYNC) {
881 /* Round up start sector, round down end sector. We make sure
882 * we only clear full, aligned, BM_BLOCK_SIZE blocks. */
883 if (unlikely(esector < BM_SECT_PER_BIT-1))
884 goto out;
885 if (unlikely(esector == (nr_sectors-1)))
886 ebnr = lbnr;
887 else
888 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
889 sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
890 } else {
891 /* We set it out of sync, or record resync failure.
892 * Should not round anything here. */
893 sbnr = BM_SECT_TO_BIT(sector);
894 ebnr = BM_SECT_TO_BIT(esector);
895 }
896
897 count = update_sync_bits(device, sbnr, ebnr, mode);
898out:
899 put_ldev(device);
900 return count;
901}
902
903static
904struct bm_extent *_bme_get(struct drbd_device *device, unsigned int enr)
905{
906 struct lc_element *e;
907 struct bm_extent *bm_ext;
908 int wakeup = 0;
909 unsigned long rs_flags;
910
911 spin_lock_irq(lock: &device->al_lock);
912 if (device->resync_locked > device->resync->nr_elements/2) {
913 spin_unlock_irq(lock: &device->al_lock);
914 return NULL;
915 }
916 e = lc_get(lc: device->resync, enr);
917 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
918 if (bm_ext) {
919 if (bm_ext->lce.lc_number != enr) {
920 bm_ext->rs_left = drbd_bm_e_weight(device, enr);
921 bm_ext->rs_failed = 0;
922 lc_committed(lc: device->resync);
923 wakeup = 1;
924 }
925 if (bm_ext->lce.refcnt == 1)
926 device->resync_locked++;
927 set_bit(BME_NO_WRITES, addr: &bm_ext->flags);
928 }
929 rs_flags = device->resync->flags;
930 spin_unlock_irq(lock: &device->al_lock);
931 if (wakeup)
932 wake_up(&device->al_wait);
933
934 if (!bm_ext) {
935 if (rs_flags & LC_STARVING)
936 drbd_warn(device, "Have to wait for element"
937 " (resync LRU too small?)\n");
938 BUG_ON(rs_flags & LC_LOCKED);
939 }
940
941 return bm_ext;
942}
943
944static int _is_in_al(struct drbd_device *device, unsigned int enr)
945{
946 int rv;
947
948 spin_lock_irq(lock: &device->al_lock);
949 rv = lc_is_used(lc: device->act_log, enr);
950 spin_unlock_irq(lock: &device->al_lock);
951
952 return rv;
953}
954
955/**
956 * drbd_rs_begin_io() - Gets an extent in the resync LRU cache and sets it to BME_LOCKED
957 * @device: DRBD device.
958 * @sector: The sector number.
959 *
960 * This functions sleeps on al_wait.
961 *
962 * Returns: %0 on success, -EINTR if interrupted.
963 */
964int drbd_rs_begin_io(struct drbd_device *device, sector_t sector)
965{
966 unsigned int enr = BM_SECT_TO_EXT(sector);
967 struct bm_extent *bm_ext;
968 int i, sig;
969 bool sa;
970
971retry:
972 sig = wait_event_interruptible(device->al_wait,
973 (bm_ext = _bme_get(device, enr)));
974 if (sig)
975 return -EINTR;
976
977 if (test_bit(BME_LOCKED, &bm_ext->flags))
978 return 0;
979
980 /* step aside only while we are above c-min-rate; unless disabled. */
981 sa = drbd_rs_c_min_rate_throttle(device);
982
983 for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
984 sig = wait_event_interruptible(device->al_wait,
985 !_is_in_al(device, enr * AL_EXT_PER_BM_SECT + i) ||
986 (sa && test_bit(BME_PRIORITY, &bm_ext->flags)));
987
988 if (sig || (sa && test_bit(BME_PRIORITY, &bm_ext->flags))) {
989 spin_lock_irq(lock: &device->al_lock);
990 if (lc_put(lc: device->resync, e: &bm_ext->lce) == 0) {
991 bm_ext->flags = 0; /* clears BME_NO_WRITES and eventually BME_PRIORITY */
992 device->resync_locked--;
993 wake_up(&device->al_wait);
994 }
995 spin_unlock_irq(lock: &device->al_lock);
996 if (sig)
997 return -EINTR;
998 if (schedule_timeout_interruptible(HZ/10))
999 return -EINTR;
1000 goto retry;
1001 }
1002 }
1003 set_bit(BME_LOCKED, addr: &bm_ext->flags);
1004 return 0;
1005}
1006
1007/**
1008 * drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep
1009 * @peer_device: DRBD device.
1010 * @sector: The sector number.
1011 *
1012 * Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then
1013 * tries to set it to BME_LOCKED.
1014 *
1015 * Returns: %0 upon success, and -EAGAIN
1016 * if there is still application IO going on in this area.
1017 */
1018int drbd_try_rs_begin_io(struct drbd_peer_device *peer_device, sector_t sector)
1019{
1020 struct drbd_device *device = peer_device->device;
1021 unsigned int enr = BM_SECT_TO_EXT(sector);
1022 const unsigned int al_enr = enr*AL_EXT_PER_BM_SECT;
1023 struct lc_element *e;
1024 struct bm_extent *bm_ext;
1025 int i;
1026 bool throttle = drbd_rs_should_slow_down(peer_device, sector, throttle_if_app_is_waiting: true);
1027
1028 /* If we need to throttle, a half-locked (only marked BME_NO_WRITES,
1029 * not yet BME_LOCKED) extent needs to be kicked out explicitly if we
1030 * need to throttle. There is at most one such half-locked extent,
1031 * which is remembered in resync_wenr. */
1032
1033 if (throttle && device->resync_wenr != enr)
1034 return -EAGAIN;
1035
1036 spin_lock_irq(lock: &device->al_lock);
1037 if (device->resync_wenr != LC_FREE && device->resync_wenr != enr) {
1038 /* in case you have very heavy scattered io, it may
1039 * stall the syncer undefined if we give up the ref count
1040 * when we try again and requeue.
1041 *
1042 * if we don't give up the refcount, but the next time
1043 * we are scheduled this extent has been "synced" by new
1044 * application writes, we'd miss the lc_put on the
1045 * extent we keep the refcount on.
1046 * so we remembered which extent we had to try again, and
1047 * if the next requested one is something else, we do
1048 * the lc_put here...
1049 * we also have to wake_up
1050 */
1051 e = lc_find(lc: device->resync, enr: device->resync_wenr);
1052 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1053 if (bm_ext) {
1054 D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1055 D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1056 clear_bit(BME_NO_WRITES, addr: &bm_ext->flags);
1057 device->resync_wenr = LC_FREE;
1058 if (lc_put(lc: device->resync, e: &bm_ext->lce) == 0) {
1059 bm_ext->flags = 0;
1060 device->resync_locked--;
1061 }
1062 wake_up(&device->al_wait);
1063 } else {
1064 drbd_alert(device, "LOGIC BUG\n");
1065 }
1066 }
1067 /* TRY. */
1068 e = lc_try_get(lc: device->resync, enr);
1069 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1070 if (bm_ext) {
1071 if (test_bit(BME_LOCKED, &bm_ext->flags))
1072 goto proceed;
1073 if (!test_and_set_bit(BME_NO_WRITES, addr: &bm_ext->flags)) {
1074 device->resync_locked++;
1075 } else {
1076 /* we did set the BME_NO_WRITES,
1077 * but then could not set BME_LOCKED,
1078 * so we tried again.
1079 * drop the extra reference. */
1080 bm_ext->lce.refcnt--;
1081 D_ASSERT(device, bm_ext->lce.refcnt > 0);
1082 }
1083 goto check_al;
1084 } else {
1085 /* do we rather want to try later? */
1086 if (device->resync_locked > device->resync->nr_elements-3)
1087 goto try_again;
1088 /* Do or do not. There is no try. -- Yoda */
1089 e = lc_get(lc: device->resync, enr);
1090 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1091 if (!bm_ext) {
1092 const unsigned long rs_flags = device->resync->flags;
1093 if (rs_flags & LC_STARVING)
1094 drbd_warn(device, "Have to wait for element"
1095 " (resync LRU too small?)\n");
1096 BUG_ON(rs_flags & LC_LOCKED);
1097 goto try_again;
1098 }
1099 if (bm_ext->lce.lc_number != enr) {
1100 bm_ext->rs_left = drbd_bm_e_weight(device, enr);
1101 bm_ext->rs_failed = 0;
1102 lc_committed(lc: device->resync);
1103 wake_up(&device->al_wait);
1104 D_ASSERT(device, test_bit(BME_LOCKED, &bm_ext->flags) == 0);
1105 }
1106 set_bit(BME_NO_WRITES, addr: &bm_ext->flags);
1107 D_ASSERT(device, bm_ext->lce.refcnt == 1);
1108 device->resync_locked++;
1109 goto check_al;
1110 }
1111check_al:
1112 for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
1113 if (lc_is_used(lc: device->act_log, enr: al_enr+i))
1114 goto try_again;
1115 }
1116 set_bit(BME_LOCKED, addr: &bm_ext->flags);
1117proceed:
1118 device->resync_wenr = LC_FREE;
1119 spin_unlock_irq(lock: &device->al_lock);
1120 return 0;
1121
1122try_again:
1123 if (bm_ext) {
1124 if (throttle) {
1125 D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1126 D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1127 clear_bit(BME_NO_WRITES, addr: &bm_ext->flags);
1128 device->resync_wenr = LC_FREE;
1129 if (lc_put(lc: device->resync, e: &bm_ext->lce) == 0) {
1130 bm_ext->flags = 0;
1131 device->resync_locked--;
1132 }
1133 wake_up(&device->al_wait);
1134 } else
1135 device->resync_wenr = enr;
1136 }
1137 spin_unlock_irq(lock: &device->al_lock);
1138 return -EAGAIN;
1139}
1140
1141void drbd_rs_complete_io(struct drbd_device *device, sector_t sector)
1142{
1143 unsigned int enr = BM_SECT_TO_EXT(sector);
1144 struct lc_element *e;
1145 struct bm_extent *bm_ext;
1146 unsigned long flags;
1147
1148 spin_lock_irqsave(&device->al_lock, flags);
1149 e = lc_find(lc: device->resync, enr);
1150 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1151 if (!bm_ext) {
1152 spin_unlock_irqrestore(lock: &device->al_lock, flags);
1153 if (drbd_ratelimit())
1154 drbd_err(device, "drbd_rs_complete_io() called, but extent not found\n");
1155 return;
1156 }
1157
1158 if (bm_ext->lce.refcnt == 0) {
1159 spin_unlock_irqrestore(lock: &device->al_lock, flags);
1160 drbd_err(device, "drbd_rs_complete_io(,%llu [=%u]) called, "
1161 "but refcnt is 0!?\n",
1162 (unsigned long long)sector, enr);
1163 return;
1164 }
1165
1166 if (lc_put(lc: device->resync, e: &bm_ext->lce) == 0) {
1167 bm_ext->flags = 0; /* clear BME_LOCKED, BME_NO_WRITES and BME_PRIORITY */
1168 device->resync_locked--;
1169 wake_up(&device->al_wait);
1170 }
1171
1172 spin_unlock_irqrestore(lock: &device->al_lock, flags);
1173}
1174
1175/**
1176 * drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED)
1177 * @device: DRBD device.
1178 */
1179void drbd_rs_cancel_all(struct drbd_device *device)
1180{
1181 spin_lock_irq(lock: &device->al_lock);
1182
1183 if (get_ldev_if_state(device, D_FAILED)) { /* Makes sure ->resync is there. */
1184 lc_reset(lc: device->resync);
1185 put_ldev(device);
1186 }
1187 device->resync_locked = 0;
1188 device->resync_wenr = LC_FREE;
1189 spin_unlock_irq(lock: &device->al_lock);
1190 wake_up(&device->al_wait);
1191}
1192
1193/**
1194 * drbd_rs_del_all() - Gracefully remove all extents from the resync LRU
1195 * @device: DRBD device.
1196 *
1197 * Returns: %0 upon success, -EAGAIN if at least one reference count was
1198 * not zero.
1199 */
1200int drbd_rs_del_all(struct drbd_device *device)
1201{
1202 struct lc_element *e;
1203 struct bm_extent *bm_ext;
1204 int i;
1205
1206 spin_lock_irq(lock: &device->al_lock);
1207
1208 if (get_ldev_if_state(device, D_FAILED)) {
1209 /* ok, ->resync is there. */
1210 for (i = 0; i < device->resync->nr_elements; i++) {
1211 e = lc_element_by_index(lc: device->resync, i);
1212 bm_ext = lc_entry(e, struct bm_extent, lce);
1213 if (bm_ext->lce.lc_number == LC_FREE)
1214 continue;
1215 if (bm_ext->lce.lc_number == device->resync_wenr) {
1216 drbd_info(device, "dropping %u in drbd_rs_del_all, apparently"
1217 " got 'synced' by application io\n",
1218 device->resync_wenr);
1219 D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1220 D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1221 clear_bit(BME_NO_WRITES, addr: &bm_ext->flags);
1222 device->resync_wenr = LC_FREE;
1223 lc_put(lc: device->resync, e: &bm_ext->lce);
1224 }
1225 if (bm_ext->lce.refcnt != 0) {
1226 drbd_info(device, "Retrying drbd_rs_del_all() later. "
1227 "refcnt=%d\n", bm_ext->lce.refcnt);
1228 put_ldev(device);
1229 spin_unlock_irq(lock: &device->al_lock);
1230 return -EAGAIN;
1231 }
1232 D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1233 D_ASSERT(device, !test_bit(BME_NO_WRITES, &bm_ext->flags));
1234 lc_del(lc: device->resync, element: &bm_ext->lce);
1235 }
1236 D_ASSERT(device, device->resync->used == 0);
1237 put_ldev(device);
1238 }
1239 spin_unlock_irq(lock: &device->al_lock);
1240 wake_up(&device->al_wait);
1241
1242 return 0;
1243}
1244

source code of linux/drivers/block/drbd/drbd_actlog.c