xref: /openbmc/linux/drivers/block/drbd/drbd_actlog.c (revision 0d11f3cf)
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 
21 enum al_transaction_types {
22 	AL_TR_UPDATE = 0,
23 	AL_TR_INITIALIZED = 0xffff
24 };
25 /* all fields on disc in big endian */
26 struct __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 
drbd_md_get_buffer(struct drbd_device * device,const char * intent)82 void *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 
drbd_md_put_buffer(struct drbd_device * device)99 void drbd_md_put_buffer(struct drbd_device *device)
100 {
101 	if (atomic_dec_and_test(&device->md_io.in_use))
102 		wake_up(&device->misc_wait);
103 }
104 
wait_until_done_or_force_detached(struct drbd_device * device,struct drbd_backing_dev * bdev,unsigned int * done)105 void 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 
_drbd_md_sync_page_io(struct drbd_device * device,struct drbd_backing_dev * bdev,sector_t sector,enum req_op op)125 static 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->md_bdev, 1, op | op_flags, GFP_NOIO,
143 			       &drbd_md_io_bio_set);
144 	bio->bi_iter.bi_sector = sector;
145 	err = -EIO;
146 	if (bio_add_page(bio, device->md_io.page, size, 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(&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, (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, &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 
drbd_md_sync_page_io(struct drbd_device * device,struct drbd_backing_dev * bdev,sector_t sector,enum req_op op)177 int 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 
find_active_resync_extent(struct drbd_device * device,unsigned int enr)206 static struct bm_extent *find_active_resync_extent(struct drbd_device *device, unsigned int enr)
207 {
208 	struct lc_element *tmp;
209 	tmp = lc_find(device->resync, 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 
_al_get(struct drbd_device * device,unsigned int enr,bool nonblock)218 static 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(&device->al_lock);
225 	bm_ext = find_active_resync_extent(device, enr);
226 	if (bm_ext) {
227 		wake = !test_and_set_bit(BME_PRIORITY, &bm_ext->flags);
228 		spin_unlock_irq(&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(device->act_log, enr);
235 	else
236 		al_ext = lc_get(device->act_log, enr);
237 	spin_unlock_irq(&device->al_lock);
238 	return al_ext;
239 }
240 
drbd_al_begin_io_fastpath(struct drbd_device * device,struct drbd_interval * i)241 bool 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, first, true);
256 }
257 
drbd_al_begin_io_prepare(struct drbd_device * device,struct drbd_interval * i)258 bool 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 
al_extent_to_bm_page(unsigned int al_enr)289 static 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 
al_tr_number_to_on_disk_sector(struct drbd_device * device)298 static 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 
__al_write_transaction(struct drbd_device * device,struct al_transaction_on_disk * buffer)316 static 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(&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 					al_extent_to_bm_page(e->lc_number));
348 		i++;
349 	}
350 	spin_unlock_irq(&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(device->act_log, 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(0, buffer, 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, device->ldev, sector, 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 
al_write_transaction(struct drbd_device * device)402 static 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, __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 
drbd_al_begin_io_commit(struct drbd_device * device)439 void 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(&device->al_lock);
463 			/* FIXME
464 			if (err)
465 				we need an "lc_cancel" here;
466 			*/
467 			lc_committed(device->act_log);
468 			spin_unlock_irq(&device->al_lock);
469 		}
470 		lc_unlock(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  */
drbd_al_begin_io(struct drbd_device * device,struct drbd_interval * i)478 void 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 
drbd_al_begin_io_nonblock(struct drbd_device * device,struct drbd_interval * i)484 int 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(device->resync, 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, &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(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 
drbd_al_complete_io(struct drbd_device * device,struct drbd_interval * i)544 void 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(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(device->act_log, extent);
564 	}
565 	spin_unlock_irqrestore(&device->al_lock, flags);
566 	wake_up(&device->al_wait);
567 }
568 
_try_lc_del(struct drbd_device * device,struct lc_element * al_ext)569 static int _try_lc_del(struct drbd_device *device, struct lc_element *al_ext)
570 {
571 	int rv;
572 
573 	spin_lock_irq(&device->al_lock);
574 	rv = (al_ext->refcnt == 0);
575 	if (likely(rv))
576 		lc_del(device->act_log, al_ext);
577 	spin_unlock_irq(&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  */
drbd_al_shrink(struct drbd_device * device)591 void 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(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 
drbd_al_initialize(struct drbd_device * device,void * buffer)608 int 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, al);
616 	/* There may or may not have been a pending transaction. */
617 	spin_lock_irq(&device->al_lock);
618 	lc_committed(device->act_log);
619 	spin_unlock_irq(&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, al);
626 		if (err)
627 			return err;
628 	}
629 	return 0;
630 }
631 
632 static 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  */
update_rs_extent(struct drbd_device * device,unsigned int enr,int count,enum update_sync_bits_mode mode)651 static 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(device->resync, enr);
668 	else
669 		e = lc_get(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(device->resync);
719 		}
720 		if (mode != SET_OUT_OF_SYNC)
721 			lc_put(device->resync, &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 
drbd_advance_rs_marks(struct drbd_peer_device * peer_device,unsigned long still_to_go)738 void 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. */
lazy_bitmap_update_due(struct drbd_device * device)756 static bool lazy_bitmap_update_due(struct drbd_device *device)
757 {
758 	return time_after(jiffies, device->rs_last_bcast + 2*HZ);
759 }
760 
maybe_schedule_on_disk_bitmap_update(struct drbd_device * device,bool rs_done)761 static 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(device->state.conn))
767 			set_bit(RS_DONE, &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, RS_PROGRESS);
778 }
779 
update_sync_bits(struct drbd_device * device,unsigned long sbnr,unsigned long ebnr,enum update_sync_bits_mode mode)780 static 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, sbnr, tbnr);
806 		else if (mode == SET_IN_SYNC)
807 			c = drbd_bm_clear_bits(device, sbnr, tbnr);
808 		else /* if (mode == SET_OUT_OF_SYNC) */
809 			c = drbd_bm_set_bits(device, sbnr, tbnr);
810 
811 		if (c) {
812 			spin_lock_irqsave(&device->al_lock, flags);
813 			cleared += update_rs_extent(device, BM_BIT_TO_EXT(sbnr), c, mode);
814 			spin_unlock_irqrestore(&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(first_peer_device(device), still_to_go);
824 			if (cleared || rs_is_done)
825 				maybe_schedule_on_disk_bitmap_update(device, 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 
plausible_request_size(int size)833 static 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 a bits of the affected
842  * one ore more _aligned_ BM_BLOCK_SIZE blocks.
843  *
844  * called by worker on C_SYNC_TARGET and receiver on SyncSource.
845  *
846  */
__drbd_change_sync(struct drbd_peer_device * peer_device,sector_t sector,int size,enum update_sync_bits_mode mode)847 int __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(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);
898 out:
899 	put_ldev(device);
900 	return count;
901 }
902 
903 static
_bme_get(struct drbd_device * device,unsigned int enr)904 struct 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(&device->al_lock);
912 	if (device->resync_locked > device->resync->nr_elements/2) {
913 		spin_unlock_irq(&device->al_lock);
914 		return NULL;
915 	}
916 	e = lc_get(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(device->resync);
923 			wakeup = 1;
924 		}
925 		if (bm_ext->lce.refcnt == 1)
926 			device->resync_locked++;
927 		set_bit(BME_NO_WRITES, &bm_ext->flags);
928 	}
929 	rs_flags = device->resync->flags;
930 	spin_unlock_irq(&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 
_is_in_al(struct drbd_device * device,unsigned int enr)944 static int _is_in_al(struct drbd_device *device, unsigned int enr)
945 {
946 	int rv;
947 
948 	spin_lock_irq(&device->al_lock);
949 	rv = lc_is_used(device->act_log, enr);
950 	spin_unlock_irq(&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. Returns 0 on success, -EINTR if interrupted.
961  */
drbd_rs_begin_io(struct drbd_device * device,sector_t sector)962 int drbd_rs_begin_io(struct drbd_device *device, sector_t sector)
963 {
964 	unsigned int enr = BM_SECT_TO_EXT(sector);
965 	struct bm_extent *bm_ext;
966 	int i, sig;
967 	bool sa;
968 
969 retry:
970 	sig = wait_event_interruptible(device->al_wait,
971 			(bm_ext = _bme_get(device, enr)));
972 	if (sig)
973 		return -EINTR;
974 
975 	if (test_bit(BME_LOCKED, &bm_ext->flags))
976 		return 0;
977 
978 	/* step aside only while we are above c-min-rate; unless disabled. */
979 	sa = drbd_rs_c_min_rate_throttle(device);
980 
981 	for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
982 		sig = wait_event_interruptible(device->al_wait,
983 					       !_is_in_al(device, enr * AL_EXT_PER_BM_SECT + i) ||
984 					       (sa && test_bit(BME_PRIORITY, &bm_ext->flags)));
985 
986 		if (sig || (sa && test_bit(BME_PRIORITY, &bm_ext->flags))) {
987 			spin_lock_irq(&device->al_lock);
988 			if (lc_put(device->resync, &bm_ext->lce) == 0) {
989 				bm_ext->flags = 0; /* clears BME_NO_WRITES and eventually BME_PRIORITY */
990 				device->resync_locked--;
991 				wake_up(&device->al_wait);
992 			}
993 			spin_unlock_irq(&device->al_lock);
994 			if (sig)
995 				return -EINTR;
996 			if (schedule_timeout_interruptible(HZ/10))
997 				return -EINTR;
998 			goto retry;
999 		}
1000 	}
1001 	set_bit(BME_LOCKED, &bm_ext->flags);
1002 	return 0;
1003 }
1004 
1005 /**
1006  * drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep
1007  * @device:	DRBD device.
1008  * @sector:	The sector number.
1009  *
1010  * Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then
1011  * tries to set it to BME_LOCKED. Returns 0 upon success, and -EAGAIN
1012  * if there is still application IO going on in this area.
1013  */
drbd_try_rs_begin_io(struct drbd_peer_device * peer_device,sector_t sector)1014 int drbd_try_rs_begin_io(struct drbd_peer_device *peer_device, sector_t sector)
1015 {
1016 	struct drbd_device *device = peer_device->device;
1017 	unsigned int enr = BM_SECT_TO_EXT(sector);
1018 	const unsigned int al_enr = enr*AL_EXT_PER_BM_SECT;
1019 	struct lc_element *e;
1020 	struct bm_extent *bm_ext;
1021 	int i;
1022 	bool throttle = drbd_rs_should_slow_down(peer_device, sector, true);
1023 
1024 	/* If we need to throttle, a half-locked (only marked BME_NO_WRITES,
1025 	 * not yet BME_LOCKED) extent needs to be kicked out explicitly if we
1026 	 * need to throttle. There is at most one such half-locked extent,
1027 	 * which is remembered in resync_wenr. */
1028 
1029 	if (throttle && device->resync_wenr != enr)
1030 		return -EAGAIN;
1031 
1032 	spin_lock_irq(&device->al_lock);
1033 	if (device->resync_wenr != LC_FREE && device->resync_wenr != enr) {
1034 		/* in case you have very heavy scattered io, it may
1035 		 * stall the syncer undefined if we give up the ref count
1036 		 * when we try again and requeue.
1037 		 *
1038 		 * if we don't give up the refcount, but the next time
1039 		 * we are scheduled this extent has been "synced" by new
1040 		 * application writes, we'd miss the lc_put on the
1041 		 * extent we keep the refcount on.
1042 		 * so we remembered which extent we had to try again, and
1043 		 * if the next requested one is something else, we do
1044 		 * the lc_put here...
1045 		 * we also have to wake_up
1046 		 */
1047 		e = lc_find(device->resync, device->resync_wenr);
1048 		bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1049 		if (bm_ext) {
1050 			D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1051 			D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1052 			clear_bit(BME_NO_WRITES, &bm_ext->flags);
1053 			device->resync_wenr = LC_FREE;
1054 			if (lc_put(device->resync, &bm_ext->lce) == 0) {
1055 				bm_ext->flags = 0;
1056 				device->resync_locked--;
1057 			}
1058 			wake_up(&device->al_wait);
1059 		} else {
1060 			drbd_alert(device, "LOGIC BUG\n");
1061 		}
1062 	}
1063 	/* TRY. */
1064 	e = lc_try_get(device->resync, enr);
1065 	bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1066 	if (bm_ext) {
1067 		if (test_bit(BME_LOCKED, &bm_ext->flags))
1068 			goto proceed;
1069 		if (!test_and_set_bit(BME_NO_WRITES, &bm_ext->flags)) {
1070 			device->resync_locked++;
1071 		} else {
1072 			/* we did set the BME_NO_WRITES,
1073 			 * but then could not set BME_LOCKED,
1074 			 * so we tried again.
1075 			 * drop the extra reference. */
1076 			bm_ext->lce.refcnt--;
1077 			D_ASSERT(device, bm_ext->lce.refcnt > 0);
1078 		}
1079 		goto check_al;
1080 	} else {
1081 		/* do we rather want to try later? */
1082 		if (device->resync_locked > device->resync->nr_elements-3)
1083 			goto try_again;
1084 		/* Do or do not. There is no try. -- Yoda */
1085 		e = lc_get(device->resync, enr);
1086 		bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1087 		if (!bm_ext) {
1088 			const unsigned long rs_flags = device->resync->flags;
1089 			if (rs_flags & LC_STARVING)
1090 				drbd_warn(device, "Have to wait for element"
1091 				     " (resync LRU too small?)\n");
1092 			BUG_ON(rs_flags & LC_LOCKED);
1093 			goto try_again;
1094 		}
1095 		if (bm_ext->lce.lc_number != enr) {
1096 			bm_ext->rs_left = drbd_bm_e_weight(device, enr);
1097 			bm_ext->rs_failed = 0;
1098 			lc_committed(device->resync);
1099 			wake_up(&device->al_wait);
1100 			D_ASSERT(device, test_bit(BME_LOCKED, &bm_ext->flags) == 0);
1101 		}
1102 		set_bit(BME_NO_WRITES, &bm_ext->flags);
1103 		D_ASSERT(device, bm_ext->lce.refcnt == 1);
1104 		device->resync_locked++;
1105 		goto check_al;
1106 	}
1107 check_al:
1108 	for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
1109 		if (lc_is_used(device->act_log, al_enr+i))
1110 			goto try_again;
1111 	}
1112 	set_bit(BME_LOCKED, &bm_ext->flags);
1113 proceed:
1114 	device->resync_wenr = LC_FREE;
1115 	spin_unlock_irq(&device->al_lock);
1116 	return 0;
1117 
1118 try_again:
1119 	if (bm_ext) {
1120 		if (throttle) {
1121 			D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1122 			D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1123 			clear_bit(BME_NO_WRITES, &bm_ext->flags);
1124 			device->resync_wenr = LC_FREE;
1125 			if (lc_put(device->resync, &bm_ext->lce) == 0) {
1126 				bm_ext->flags = 0;
1127 				device->resync_locked--;
1128 			}
1129 			wake_up(&device->al_wait);
1130 		} else
1131 			device->resync_wenr = enr;
1132 	}
1133 	spin_unlock_irq(&device->al_lock);
1134 	return -EAGAIN;
1135 }
1136 
drbd_rs_complete_io(struct drbd_device * device,sector_t sector)1137 void drbd_rs_complete_io(struct drbd_device *device, sector_t sector)
1138 {
1139 	unsigned int enr = BM_SECT_TO_EXT(sector);
1140 	struct lc_element *e;
1141 	struct bm_extent *bm_ext;
1142 	unsigned long flags;
1143 
1144 	spin_lock_irqsave(&device->al_lock, flags);
1145 	e = lc_find(device->resync, enr);
1146 	bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1147 	if (!bm_ext) {
1148 		spin_unlock_irqrestore(&device->al_lock, flags);
1149 		if (drbd_ratelimit())
1150 			drbd_err(device, "drbd_rs_complete_io() called, but extent not found\n");
1151 		return;
1152 	}
1153 
1154 	if (bm_ext->lce.refcnt == 0) {
1155 		spin_unlock_irqrestore(&device->al_lock, flags);
1156 		drbd_err(device, "drbd_rs_complete_io(,%llu [=%u]) called, "
1157 		    "but refcnt is 0!?\n",
1158 		    (unsigned long long)sector, enr);
1159 		return;
1160 	}
1161 
1162 	if (lc_put(device->resync, &bm_ext->lce) == 0) {
1163 		bm_ext->flags = 0; /* clear BME_LOCKED, BME_NO_WRITES and BME_PRIORITY */
1164 		device->resync_locked--;
1165 		wake_up(&device->al_wait);
1166 	}
1167 
1168 	spin_unlock_irqrestore(&device->al_lock, flags);
1169 }
1170 
1171 /**
1172  * drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED)
1173  * @device:	DRBD device.
1174  */
drbd_rs_cancel_all(struct drbd_device * device)1175 void drbd_rs_cancel_all(struct drbd_device *device)
1176 {
1177 	spin_lock_irq(&device->al_lock);
1178 
1179 	if (get_ldev_if_state(device, D_FAILED)) { /* Makes sure ->resync is there. */
1180 		lc_reset(device->resync);
1181 		put_ldev(device);
1182 	}
1183 	device->resync_locked = 0;
1184 	device->resync_wenr = LC_FREE;
1185 	spin_unlock_irq(&device->al_lock);
1186 	wake_up(&device->al_wait);
1187 }
1188 
1189 /**
1190  * drbd_rs_del_all() - Gracefully remove all extents from the resync LRU
1191  * @device:	DRBD device.
1192  *
1193  * Returns 0 upon success, -EAGAIN if at least one reference count was
1194  * not zero.
1195  */
drbd_rs_del_all(struct drbd_device * device)1196 int drbd_rs_del_all(struct drbd_device *device)
1197 {
1198 	struct lc_element *e;
1199 	struct bm_extent *bm_ext;
1200 	int i;
1201 
1202 	spin_lock_irq(&device->al_lock);
1203 
1204 	if (get_ldev_if_state(device, D_FAILED)) {
1205 		/* ok, ->resync is there. */
1206 		for (i = 0; i < device->resync->nr_elements; i++) {
1207 			e = lc_element_by_index(device->resync, i);
1208 			bm_ext = lc_entry(e, struct bm_extent, lce);
1209 			if (bm_ext->lce.lc_number == LC_FREE)
1210 				continue;
1211 			if (bm_ext->lce.lc_number == device->resync_wenr) {
1212 				drbd_info(device, "dropping %u in drbd_rs_del_all, apparently"
1213 				     " got 'synced' by application io\n",
1214 				     device->resync_wenr);
1215 				D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1216 				D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1217 				clear_bit(BME_NO_WRITES, &bm_ext->flags);
1218 				device->resync_wenr = LC_FREE;
1219 				lc_put(device->resync, &bm_ext->lce);
1220 			}
1221 			if (bm_ext->lce.refcnt != 0) {
1222 				drbd_info(device, "Retrying drbd_rs_del_all() later. "
1223 				     "refcnt=%d\n", bm_ext->lce.refcnt);
1224 				put_ldev(device);
1225 				spin_unlock_irq(&device->al_lock);
1226 				return -EAGAIN;
1227 			}
1228 			D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1229 			D_ASSERT(device, !test_bit(BME_NO_WRITES, &bm_ext->flags));
1230 			lc_del(device->resync, &bm_ext->lce);
1231 		}
1232 		D_ASSERT(device, device->resync->used == 0);
1233 		put_ldev(device);
1234 	}
1235 	spin_unlock_irq(&device->al_lock);
1236 	wake_up(&device->al_wait);
1237 
1238 	return 0;
1239 }
1240