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1/*
2 drbd_actlog.c
3
4 This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
5
6 Copyright (C) 2003-2008, LINBIT Information Technologies GmbH.
7 Copyright (C) 2003-2008, Philipp Reisner <philipp.reisner@linbit.com>.
8 Copyright (C) 2003-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
9
10 drbd is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 2, or (at your option)
13 any later version.
14
15 drbd is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
19
20 You should have received a copy of the GNU General Public License
21 along with drbd; see the file COPYING. If not, write to
22 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
23
24 */
25
26#include <linux/slab.h>
27#include <linux/drbd.h>
28#include "drbd_int.h"
29#include "drbd_wrappers.h"
30
31/* We maintain a trivial checksum in our on disk activity log.
32 * With that we can ensure correct operation even when the storage
33 * device might do a partial (last) sector write while losing power.
34 */
35struct __packed al_transaction {
36 u32 magic;
37 u32 tr_number;
38 struct __packed {
39 u32 pos;
40 u32 extent; } updates[1 + AL_EXTENTS_PT];
41 u32 xor_sum;
42};
43
44struct update_odbm_work {
45 struct drbd_work w;
46 unsigned int enr;
47};
48
49struct update_al_work {
50 struct drbd_work w;
51 struct lc_element *al_ext;
52 struct completion event;
53 unsigned int enr;
54 /* if old_enr != LC_FREE, write corresponding bitmap sector, too */
55 unsigned int old_enr;
56};
57
58struct drbd_atodb_wait {
59 atomic_t count;
60 struct completion io_done;
61 struct drbd_conf *mdev;
62 int error;
63};
64
65
66int w_al_write_transaction(struct drbd_conf *, struct drbd_work *, int);
67
68static int _drbd_md_sync_page_io(struct drbd_conf *mdev,
69 struct drbd_backing_dev *bdev,
70 struct page *page, sector_t sector,
71 int rw, int size)
72{
73 struct bio *bio;
74 struct drbd_md_io md_io;
75 int ok;
76
77 md_io.mdev = mdev;
78 init_completion(&md_io.event);
79 md_io.error = 0;
80
81 if ((rw & WRITE) && !test_bit(MD_NO_FUA, &mdev->flags))
82 rw |= REQ_FUA | REQ_FLUSH;
83 rw |= REQ_SYNC;
84
85 bio = bio_alloc(GFP_NOIO, 1);
86 bio->bi_bdev = bdev->md_bdev;
87 bio->bi_sector = sector;
88 ok = (bio_add_page(bio, page, size, 0) == size);
89 if (!ok)
90 goto out;
91 bio->bi_private = &md_io;
92 bio->bi_end_io = drbd_md_io_complete;
93 bio->bi_rw = rw;
94
95 if (drbd_insert_fault(mdev, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD))
96 bio_endio(bio, -EIO);
97 else
98 submit_bio(rw, bio);
99 wait_for_completion(&md_io.event);
100 ok = bio_flagged(bio, BIO_UPTODATE) && md_io.error == 0;
101
102 out:
103 bio_put(bio);
104 return ok;
105}
106
107int drbd_md_sync_page_io(struct drbd_conf *mdev, struct drbd_backing_dev *bdev,
108 sector_t sector, int rw)
109{
110 int logical_block_size, mask, ok;
111 int offset = 0;
112 struct page *iop = mdev->md_io_page;
113
114 D_ASSERT(mutex_is_locked(&mdev->md_io_mutex));
115
116 BUG_ON(!bdev->md_bdev);
117
118 logical_block_size = bdev_logical_block_size(bdev->md_bdev);
119 if (logical_block_size == 0)
120 logical_block_size = MD_SECTOR_SIZE;
121
122 /* in case logical_block_size != 512 [ s390 only? ] */
123 if (logical_block_size != MD_SECTOR_SIZE) {
124 mask = (logical_block_size / MD_SECTOR_SIZE) - 1;
125 D_ASSERT(mask == 1 || mask == 3 || mask == 7);
126 D_ASSERT(logical_block_size == (mask+1) * MD_SECTOR_SIZE);
127 offset = sector & mask;
128 sector = sector & ~mask;
129 iop = mdev->md_io_tmpp;
130
131 if (rw & WRITE) {
132 /* these are GFP_KERNEL pages, pre-allocated
133 * on device initialization */
134 void *p = page_address(mdev->md_io_page);
135 void *hp = page_address(mdev->md_io_tmpp);
136
137 ok = _drbd_md_sync_page_io(mdev, bdev, iop, sector,
138 READ, logical_block_size);
139
140 if (unlikely(!ok)) {
141 dev_err(DEV, "drbd_md_sync_page_io(,%llus,"
142 "READ [logical_block_size!=512]) failed!\n",
143 (unsigned long long)sector);
144 return 0;
145 }
146
147 memcpy(hp + offset*MD_SECTOR_SIZE, p, MD_SECTOR_SIZE);
148 }
149 }
150
151 if (sector < drbd_md_first_sector(bdev) ||
152 sector > drbd_md_last_sector(bdev))
153 dev_alert(DEV, "%s [%d]:%s(,%llus,%s) out of range md access!\n",
154 current->comm, current->pid, __func__,
155 (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
156
157 ok = _drbd_md_sync_page_io(mdev, bdev, iop, sector, rw, logical_block_size);
158 if (unlikely(!ok)) {
159 dev_err(DEV, "drbd_md_sync_page_io(,%llus,%s) failed!\n",
160 (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
161 return 0;
162 }
163
164 if (logical_block_size != MD_SECTOR_SIZE && !(rw & WRITE)) {
165 void *p = page_address(mdev->md_io_page);
166 void *hp = page_address(mdev->md_io_tmpp);
167
168 memcpy(p, hp + offset*MD_SECTOR_SIZE, MD_SECTOR_SIZE);
169 }
170
171 return ok;
172}
173
174static struct lc_element *_al_get(struct drbd_conf *mdev, unsigned int enr)
175{
176 struct lc_element *al_ext;
177 struct lc_element *tmp;
178 unsigned long al_flags = 0;
179 int wake;
180
181 spin_lock_irq(&mdev->al_lock);
182 tmp = lc_find(mdev->resync, enr/AL_EXT_PER_BM_SECT);
183 if (unlikely(tmp != NULL)) {
184 struct bm_extent *bm_ext = lc_entry(tmp, struct bm_extent, lce);
185 if (test_bit(BME_NO_WRITES, &bm_ext->flags)) {
186 wake = !test_and_set_bit(BME_PRIORITY, &bm_ext->flags);
187 spin_unlock_irq(&mdev->al_lock);
188 if (wake)
189 wake_up(&mdev->al_wait);
190 return NULL;
191 }
192 }
193 al_ext = lc_get(mdev->act_log, enr);
194 al_flags = mdev->act_log->flags;
195 spin_unlock_irq(&mdev->al_lock);
196
197 /*
198 if (!al_ext) {
199 if (al_flags & LC_STARVING)
200 dev_warn(DEV, "Have to wait for LRU element (AL too small?)\n");
201 if (al_flags & LC_DIRTY)
202 dev_warn(DEV, "Ongoing AL update (AL device too slow?)\n");
203 }
204 */
205
206 return al_ext;
207}
208
209void drbd_al_begin_io(struct drbd_conf *mdev, sector_t sector)
210{
211 unsigned int enr = (sector >> (AL_EXTENT_SHIFT-9));
212 struct lc_element *al_ext;
213 struct update_al_work al_work;
214
215 D_ASSERT(atomic_read(&mdev->local_cnt) > 0);
216
217 wait_event(mdev->al_wait, (al_ext = _al_get(mdev, enr)));
218
219 if (al_ext->lc_number != enr) {
220 /* drbd_al_write_transaction(mdev,al_ext,enr);
221 * recurses into generic_make_request(), which
222 * disallows recursion, bios being serialized on the
223 * current->bio_tail list now.
224 * we have to delegate updates to the activity log
225 * to the worker thread. */
226 init_completion(&al_work.event);
227 al_work.al_ext = al_ext;
228 al_work.enr = enr;
229 al_work.old_enr = al_ext->lc_number;
230 al_work.w.cb = w_al_write_transaction;
231 drbd_queue_work_front(&mdev->data.work, &al_work.w);
232 wait_for_completion(&al_work.event);
233
234 mdev->al_writ_cnt++;
235
236 spin_lock_irq(&mdev->al_lock);
237 lc_changed(mdev->act_log, al_ext);
238 spin_unlock_irq(&mdev->al_lock);
239 wake_up(&mdev->al_wait);
240 }
241}
242
243void drbd_al_complete_io(struct drbd_conf *mdev, sector_t sector)
244{
245 unsigned int enr = (sector >> (AL_EXTENT_SHIFT-9));
246 struct lc_element *extent;
247 unsigned long flags;
248
249 spin_lock_irqsave(&mdev->al_lock, flags);
250
251 extent = lc_find(mdev->act_log, enr);
252
253 if (!extent) {
254 spin_unlock_irqrestore(&mdev->al_lock, flags);
255 dev_err(DEV, "al_complete_io() called on inactive extent %u\n", enr);
256 return;
257 }
258
259 if (lc_put(mdev->act_log, extent) == 0)
260 wake_up(&mdev->al_wait);
261
262 spin_unlock_irqrestore(&mdev->al_lock, flags);
263}
264
265#if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)
266/* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT
267 * are still coupled, or assume too much about their relation.
268 * Code below will not work if this is violated.
269 * Will be cleaned up with some followup patch.
270 */
271# error FIXME
272#endif
273
274static unsigned int al_extent_to_bm_page(unsigned int al_enr)
275{
276 return al_enr >>
277 /* bit to page */
278 ((PAGE_SHIFT + 3) -
279 /* al extent number to bit */
280 (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT));
281}
282
283static unsigned int rs_extent_to_bm_page(unsigned int rs_enr)
284{
285 return rs_enr >>
286 /* bit to page */
287 ((PAGE_SHIFT + 3) -
288 /* al extent number to bit */
289 (BM_EXT_SHIFT - BM_BLOCK_SHIFT));
290}
291
292int
293w_al_write_transaction(struct drbd_conf *mdev, struct drbd_work *w, int unused)
294{
295 struct update_al_work *aw = container_of(w, struct update_al_work, w);
296 struct lc_element *updated = aw->al_ext;
297 const unsigned int new_enr = aw->enr;
298 const unsigned int evicted = aw->old_enr;
299 struct al_transaction *buffer;
300 sector_t sector;
301 int i, n, mx;
302 unsigned int extent_nr;
303 u32 xor_sum = 0;
304
305 if (!get_ldev(mdev)) {
306 dev_err(DEV,
307 "disk is %s, cannot start al transaction (-%d +%d)\n",
308 drbd_disk_str(mdev->state.disk), evicted, new_enr);
309 complete(&((struct update_al_work *)w)->event);
310 return 1;
311 }
312 /* do we have to do a bitmap write, first?
313 * TODO reduce maximum latency:
314 * submit both bios, then wait for both,
315 * instead of doing two synchronous sector writes.
316 * For now, we must not write the transaction,
317 * if we cannot write out the bitmap of the evicted extent. */
318 if (mdev->state.conn < C_CONNECTED && evicted != LC_FREE)
319 drbd_bm_write_page(mdev, al_extent_to_bm_page(evicted));
320
321 /* The bitmap write may have failed, causing a state change. */
322 if (mdev->state.disk < D_INCONSISTENT) {
323 dev_err(DEV,
324 "disk is %s, cannot write al transaction (-%d +%d)\n",
325 drbd_disk_str(mdev->state.disk), evicted, new_enr);
326 complete(&((struct update_al_work *)w)->event);
327 put_ldev(mdev);
328 return 1;
329 }
330
331 mutex_lock(&mdev->md_io_mutex); /* protects md_io_buffer, al_tr_cycle, ... */
332 buffer = (struct al_transaction *)page_address(mdev->md_io_page);
333
334 buffer->magic = __constant_cpu_to_be32(DRBD_MAGIC);
335 buffer->tr_number = cpu_to_be32(mdev->al_tr_number);
336
337 n = lc_index_of(mdev->act_log, updated);
338
339 buffer->updates[0].pos = cpu_to_be32(n);
340 buffer->updates[0].extent = cpu_to_be32(new_enr);
341
342 xor_sum ^= new_enr;
343
344 mx = min_t(int, AL_EXTENTS_PT,
345 mdev->act_log->nr_elements - mdev->al_tr_cycle);
346 for (i = 0; i < mx; i++) {
347 unsigned idx = mdev->al_tr_cycle + i;
348 extent_nr = lc_element_by_index(mdev->act_log, idx)->lc_number;
349 buffer->updates[i+1].pos = cpu_to_be32(idx);
350 buffer->updates[i+1].extent = cpu_to_be32(extent_nr);
351 xor_sum ^= extent_nr;
352 }
353 for (; i < AL_EXTENTS_PT; i++) {
354 buffer->updates[i+1].pos = __constant_cpu_to_be32(-1);
355 buffer->updates[i+1].extent = __constant_cpu_to_be32(LC_FREE);
356 xor_sum ^= LC_FREE;
357 }
358 mdev->al_tr_cycle += AL_EXTENTS_PT;
359 if (mdev->al_tr_cycle >= mdev->act_log->nr_elements)
360 mdev->al_tr_cycle = 0;
361
362 buffer->xor_sum = cpu_to_be32(xor_sum);
363
364 sector = mdev->ldev->md.md_offset
365 + mdev->ldev->md.al_offset + mdev->al_tr_pos;
366
367 if (!drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE))
368 drbd_chk_io_error(mdev, 1, true);
369
370 if (++mdev->al_tr_pos >
371 div_ceil(mdev->act_log->nr_elements, AL_EXTENTS_PT))
372 mdev->al_tr_pos = 0;
373
374 D_ASSERT(mdev->al_tr_pos < MD_AL_MAX_SIZE);
375 mdev->al_tr_number++;
376
377 mutex_unlock(&mdev->md_io_mutex);
378
379 complete(&((struct update_al_work *)w)->event);
380 put_ldev(mdev);
381
382 return 1;
383}
384
385/**
386 * drbd_al_read_tr() - Read a single transaction from the on disk activity log
387 * @mdev: DRBD device.
388 * @bdev: Block device to read form.
389 * @b: pointer to an al_transaction.
390 * @index: On disk slot of the transaction to read.
391 *
392 * Returns -1 on IO error, 0 on checksum error and 1 upon success.
393 */
394static int drbd_al_read_tr(struct drbd_conf *mdev,
395 struct drbd_backing_dev *bdev,
396 struct al_transaction *b,
397 int index)
398{
399 sector_t sector;
400 int rv, i;
401 u32 xor_sum = 0;
402
403 sector = bdev->md.md_offset + bdev->md.al_offset + index;
404
405 /* Dont process error normally,
406 * as this is done before disk is attached! */
407 if (!drbd_md_sync_page_io(mdev, bdev, sector, READ))
408 return -1;
409
410 rv = (be32_to_cpu(b->magic) == DRBD_MAGIC);
411
412 for (i = 0; i < AL_EXTENTS_PT + 1; i++)
413 xor_sum ^= be32_to_cpu(b->updates[i].extent);
414 rv &= (xor_sum == be32_to_cpu(b->xor_sum));
415
416 return rv;
417}
418
419/**
420 * drbd_al_read_log() - Restores the activity log from its on disk representation.
421 * @mdev: DRBD device.
422 * @bdev: Block device to read form.
423 *
424 * Returns 1 on success, returns 0 when reading the log failed due to IO errors.
425 */
426int drbd_al_read_log(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
427{
428 struct al_transaction *buffer;
429 int i;
430 int rv;
431 int mx;
432 int active_extents = 0;
433 int transactions = 0;
434 int found_valid = 0;
435 int from = 0;
436 int to = 0;
437 u32 from_tnr = 0;
438 u32 to_tnr = 0;
439 u32 cnr;
440
441 mx = div_ceil(mdev->act_log->nr_elements, AL_EXTENTS_PT);
442
443 /* lock out all other meta data io for now,
444 * and make sure the page is mapped.
445 */
446 mutex_lock(&mdev->md_io_mutex);
447 buffer = page_address(mdev->md_io_page);
448
449 /* Find the valid transaction in the log */
450 for (i = 0; i <= mx; i++) {
451 rv = drbd_al_read_tr(mdev, bdev, buffer, i);
452 if (rv == 0)
453 continue;
454 if (rv == -1) {
455 mutex_unlock(&mdev->md_io_mutex);
456 return 0;
457 }
458 cnr = be32_to_cpu(buffer->tr_number);
459
460 if (++found_valid == 1) {
461 from = i;
462 to = i;
463 from_tnr = cnr;
464 to_tnr = cnr;
465 continue;
466 }
467 if ((int)cnr - (int)from_tnr < 0) {
468 D_ASSERT(from_tnr - cnr + i - from == mx+1);
469 from = i;
470 from_tnr = cnr;
471 }
472 if ((int)cnr - (int)to_tnr > 0) {
473 D_ASSERT(cnr - to_tnr == i - to);
474 to = i;
475 to_tnr = cnr;
476 }
477 }
478
479 if (!found_valid) {
480 dev_warn(DEV, "No usable activity log found.\n");
481 mutex_unlock(&mdev->md_io_mutex);
482 return 1;
483 }
484
485 /* Read the valid transactions.
486 * dev_info(DEV, "Reading from %d to %d.\n",from,to); */
487 i = from;
488 while (1) {
489 int j, pos;
490 unsigned int extent_nr;
491 unsigned int trn;
492
493 rv = drbd_al_read_tr(mdev, bdev, buffer, i);
494 ERR_IF(rv == 0) goto cancel;
495 if (rv == -1) {
496 mutex_unlock(&mdev->md_io_mutex);
497 return 0;
498 }
499
500 trn = be32_to_cpu(buffer->tr_number);
501
502 spin_lock_irq(&mdev->al_lock);
503
504 /* This loop runs backwards because in the cyclic
505 elements there might be an old version of the
506 updated element (in slot 0). So the element in slot 0
507 can overwrite old versions. */
508 for (j = AL_EXTENTS_PT; j >= 0; j--) {
509 pos = be32_to_cpu(buffer->updates[j].pos);
510 extent_nr = be32_to_cpu(buffer->updates[j].extent);
511
512 if (extent_nr == LC_FREE)
513 continue;
514
515 lc_set(mdev->act_log, extent_nr, pos);
516 active_extents++;
517 }
518 spin_unlock_irq(&mdev->al_lock);
519
520 transactions++;
521
522cancel:
523 if (i == to)
524 break;
525 i++;
526 if (i > mx)
527 i = 0;
528 }
529
530 mdev->al_tr_number = to_tnr+1;
531 mdev->al_tr_pos = to;
532 if (++mdev->al_tr_pos >
533 div_ceil(mdev->act_log->nr_elements, AL_EXTENTS_PT))
534 mdev->al_tr_pos = 0;
535
536 /* ok, we are done with it */
537 mutex_unlock(&mdev->md_io_mutex);
538
539 dev_info(DEV, "Found %d transactions (%d active extents) in activity log.\n",
540 transactions, active_extents);
541
542 return 1;
543}
544
545/**
546 * drbd_al_apply_to_bm() - Sets the bitmap to diry(1) where covered ba active AL extents
547 * @mdev: DRBD device.
548 */
549void drbd_al_apply_to_bm(struct drbd_conf *mdev)
550{
551 unsigned int enr;
552 unsigned long add = 0;
553 char ppb[10];
554 int i, tmp;
555
556 wait_event(mdev->al_wait, lc_try_lock(mdev->act_log));
557
558 for (i = 0; i < mdev->act_log->nr_elements; i++) {
559 enr = lc_element_by_index(mdev->act_log, i)->lc_number;
560 if (enr == LC_FREE)
561 continue;
562 tmp = drbd_bm_ALe_set_all(mdev, enr);
563 dynamic_dev_dbg(DEV, "AL: set %d bits in extent %u\n", tmp, enr);
564 add += tmp;
565 }
566
567 lc_unlock(mdev->act_log);
568 wake_up(&mdev->al_wait);
569
570 dev_info(DEV, "Marked additional %s as out-of-sync based on AL.\n",
571 ppsize(ppb, Bit2KB(add)));
572}
573
574static int _try_lc_del(struct drbd_conf *mdev, struct lc_element *al_ext)
575{
576 int rv;
577
578 spin_lock_irq(&mdev->al_lock);
579 rv = (al_ext->refcnt == 0);
580 if (likely(rv))
581 lc_del(mdev->act_log, al_ext);
582 spin_unlock_irq(&mdev->al_lock);
583
584 return rv;
585}
586
587/**
588 * drbd_al_shrink() - Removes all active extents form the activity log
589 * @mdev: DRBD device.
590 *
591 * Removes all active extents form the activity log, waiting until
592 * the reference count of each entry dropped to 0 first, of course.
593 *
594 * You need to lock mdev->act_log with lc_try_lock() / lc_unlock()
595 */
596void drbd_al_shrink(struct drbd_conf *mdev)
597{
598 struct lc_element *al_ext;
599 int i;
600
601 D_ASSERT(test_bit(__LC_DIRTY, &mdev->act_log->flags));
602
603 for (i = 0; i < mdev->act_log->nr_elements; i++) {
604 al_ext = lc_element_by_index(mdev->act_log, i);
605 if (al_ext->lc_number == LC_FREE)
606 continue;
607 wait_event(mdev->al_wait, _try_lc_del(mdev, al_ext));
608 }
609
610 wake_up(&mdev->al_wait);
611}
612
613static int w_update_odbm(struct drbd_conf *mdev, struct drbd_work *w, int unused)
614{
615 struct update_odbm_work *udw = container_of(w, struct update_odbm_work, w);
616
617 if (!get_ldev(mdev)) {
618 if (__ratelimit(&drbd_ratelimit_state))
619 dev_warn(DEV, "Can not update on disk bitmap, local IO disabled.\n");
620 kfree(udw);
621 return 1;
622 }
623
624 drbd_bm_write_page(mdev, rs_extent_to_bm_page(udw->enr));
625 put_ldev(mdev);
626
627 kfree(udw);
628
629 if (drbd_bm_total_weight(mdev) <= mdev->rs_failed) {
630 switch (mdev->state.conn) {
631 case C_SYNC_SOURCE: case C_SYNC_TARGET:
632 case C_PAUSED_SYNC_S: case C_PAUSED_SYNC_T:
633 drbd_resync_finished(mdev);
634 default:
635 /* nothing to do */
636 break;
637 }
638 }
639 drbd_bcast_sync_progress(mdev);
640
641 return 1;
642}
643
644
645/* ATTENTION. The AL's extents are 4MB each, while the extents in the
646 * resync LRU-cache are 16MB each.
647 * The caller of this function has to hold an get_ldev() reference.
648 *
649 * TODO will be obsoleted once we have a caching lru of the on disk bitmap
650 */
651static void drbd_try_clear_on_disk_bm(struct drbd_conf *mdev, sector_t sector,
652 int count, int success)
653{
654 struct lc_element *e;
655 struct update_odbm_work *udw;
656
657 unsigned int enr;
658
659 D_ASSERT(atomic_read(&mdev->local_cnt));
660
661 /* I simply assume that a sector/size pair never crosses
662 * a 16 MB extent border. (Currently this is true...) */
663 enr = BM_SECT_TO_EXT(sector);
664
665 e = lc_get(mdev->resync, enr);
666 if (e) {
667 struct bm_extent *ext = lc_entry(e, struct bm_extent, lce);
668 if (ext->lce.lc_number == enr) {
669 if (success)
670 ext->rs_left -= count;
671 else
672 ext->rs_failed += count;
673 if (ext->rs_left < ext->rs_failed) {
674 dev_err(DEV, "BAD! sector=%llus enr=%u rs_left=%d "
675 "rs_failed=%d count=%d\n",
676 (unsigned long long)sector,
677 ext->lce.lc_number, ext->rs_left,
678 ext->rs_failed, count);
679 dump_stack();
680
681 lc_put(mdev->resync, &ext->lce);
682 drbd_force_state(mdev, NS(conn, C_DISCONNECTING));
683 return;
684 }
685 } else {
686 /* Normally this element should be in the cache,
687 * since drbd_rs_begin_io() pulled it already in.
688 *
689 * But maybe an application write finished, and we set
690 * something outside the resync lru_cache in sync.
691 */
692 int rs_left = drbd_bm_e_weight(mdev, enr);
693 if (ext->flags != 0) {
694 dev_warn(DEV, "changing resync lce: %d[%u;%02lx]"
695 " -> %d[%u;00]\n",
696 ext->lce.lc_number, ext->rs_left,
697 ext->flags, enr, rs_left);
698 ext->flags = 0;
699 }
700 if (ext->rs_failed) {
701 dev_warn(DEV, "Kicking resync_lru element enr=%u "
702 "out with rs_failed=%d\n",
703 ext->lce.lc_number, ext->rs_failed);
704 }
705 ext->rs_left = rs_left;
706 ext->rs_failed = success ? 0 : count;
707 lc_changed(mdev->resync, &ext->lce);
708 }
709 lc_put(mdev->resync, &ext->lce);
710 /* no race, we are within the al_lock! */
711
712 if (ext->rs_left == ext->rs_failed) {
713 ext->rs_failed = 0;
714
715 udw = kmalloc(sizeof(*udw), GFP_ATOMIC);
716 if (udw) {
717 udw->enr = ext->lce.lc_number;
718 udw->w.cb = w_update_odbm;
719 drbd_queue_work_front(&mdev->data.work, &udw->w);
720 } else {
721 dev_warn(DEV, "Could not kmalloc an udw\n");
722 }
723 }
724 } else {
725 dev_err(DEV, "lc_get() failed! locked=%d/%d flags=%lu\n",
726 mdev->resync_locked,
727 mdev->resync->nr_elements,
728 mdev->resync->flags);
729 }
730}
731
732void drbd_advance_rs_marks(struct drbd_conf *mdev, unsigned long still_to_go)
733{
734 unsigned long now = jiffies;
735 unsigned long last = mdev->rs_mark_time[mdev->rs_last_mark];
736 int next = (mdev->rs_last_mark + 1) % DRBD_SYNC_MARKS;
737 if (time_after_eq(now, last + DRBD_SYNC_MARK_STEP)) {
738 if (mdev->rs_mark_left[mdev->rs_last_mark] != still_to_go &&
739 mdev->state.conn != C_PAUSED_SYNC_T &&
740 mdev->state.conn != C_PAUSED_SYNC_S) {
741 mdev->rs_mark_time[next] = now;
742 mdev->rs_mark_left[next] = still_to_go;
743 mdev->rs_last_mark = next;
744 }
745 }
746}
747
748/* clear the bit corresponding to the piece of storage in question:
749 * size byte of data starting from sector. Only clear a bits of the affected
750 * one ore more _aligned_ BM_BLOCK_SIZE blocks.
751 *
752 * called by worker on C_SYNC_TARGET and receiver on SyncSource.
753 *
754 */
755void __drbd_set_in_sync(struct drbd_conf *mdev, sector_t sector, int size,
756 const char *file, const unsigned int line)
757{
758 /* Is called from worker and receiver context _only_ */
759 unsigned long sbnr, ebnr, lbnr;
760 unsigned long count = 0;
761 sector_t esector, nr_sectors;
762 int wake_up = 0;
763 unsigned long flags;
764
765 if (size <= 0 || (size & 0x1ff) != 0 || size > DRBD_MAX_BIO_SIZE) {
766 dev_err(DEV, "drbd_set_in_sync: sector=%llus size=%d nonsense!\n",
767 (unsigned long long)sector, size);
768 return;
769 }
770 nr_sectors = drbd_get_capacity(mdev->this_bdev);
771 esector = sector + (size >> 9) - 1;
772
773 ERR_IF(sector >= nr_sectors) return;
774 ERR_IF(esector >= nr_sectors) esector = (nr_sectors-1);
775
776 lbnr = BM_SECT_TO_BIT(nr_sectors-1);
777
778 /* we clear it (in sync).
779 * round up start sector, round down end sector. we make sure we only
780 * clear full, aligned, BM_BLOCK_SIZE (4K) blocks */
781 if (unlikely(esector < BM_SECT_PER_BIT-1))
782 return;
783 if (unlikely(esector == (nr_sectors-1)))
784 ebnr = lbnr;
785 else
786 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
787 sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
788
789 if (sbnr > ebnr)
790 return;
791
792 /*
793 * ok, (capacity & 7) != 0 sometimes, but who cares...
794 * we count rs_{total,left} in bits, not sectors.
795 */
796 count = drbd_bm_clear_bits(mdev, sbnr, ebnr);
797 if (count && get_ldev(mdev)) {
798 drbd_advance_rs_marks(mdev, drbd_bm_total_weight(mdev));
799 spin_lock_irqsave(&mdev->al_lock, flags);
800 drbd_try_clear_on_disk_bm(mdev, sector, count, true);
801 spin_unlock_irqrestore(&mdev->al_lock, flags);
802
803 /* just wake_up unconditional now, various lc_chaged(),
804 * lc_put() in drbd_try_clear_on_disk_bm(). */
805 wake_up = 1;
806 put_ldev(mdev);
807 }
808 if (wake_up)
809 wake_up(&mdev->al_wait);
810}
811
812/*
813 * this is intended to set one request worth of data out of sync.
814 * affects at least 1 bit,
815 * and at most 1+DRBD_MAX_BIO_SIZE/BM_BLOCK_SIZE bits.
816 *
817 * called by tl_clear and drbd_send_dblock (==drbd_make_request).
818 * so this can be _any_ process.
819 */
820int __drbd_set_out_of_sync(struct drbd_conf *mdev, sector_t sector, int size,
821 const char *file, const unsigned int line)
822{
823 unsigned long sbnr, ebnr, lbnr, flags;
824 sector_t esector, nr_sectors;
825 unsigned int enr, count = 0;
826 struct lc_element *e;
827
828 if (size <= 0 || (size & 0x1ff) != 0 || size > DRBD_MAX_BIO_SIZE) {
829 dev_err(DEV, "sector: %llus, size: %d\n",
830 (unsigned long long)sector, size);
831 return 0;
832 }
833
834 if (!get_ldev(mdev))
835 return 0; /* no disk, no metadata, no bitmap to set bits in */
836
837 nr_sectors = drbd_get_capacity(mdev->this_bdev);
838 esector = sector + (size >> 9) - 1;
839
840 ERR_IF(sector >= nr_sectors)
841 goto out;
842 ERR_IF(esector >= nr_sectors)
843 esector = (nr_sectors-1);
844
845 lbnr = BM_SECT_TO_BIT(nr_sectors-1);
846
847 /* we set it out of sync,
848 * we do not need to round anything here */
849 sbnr = BM_SECT_TO_BIT(sector);
850 ebnr = BM_SECT_TO_BIT(esector);
851
852 /* ok, (capacity & 7) != 0 sometimes, but who cares...
853 * we count rs_{total,left} in bits, not sectors. */
854 spin_lock_irqsave(&mdev->al_lock, flags);
855 count = drbd_bm_set_bits(mdev, sbnr, ebnr);
856
857 enr = BM_SECT_TO_EXT(sector);
858 e = lc_find(mdev->resync, enr);
859 if (e)
860 lc_entry(e, struct bm_extent, lce)->rs_left += count;
861 spin_unlock_irqrestore(&mdev->al_lock, flags);
862
863out:
864 put_ldev(mdev);
865
866 return count;
867}
868
869static
870struct bm_extent *_bme_get(struct drbd_conf *mdev, unsigned int enr)
871{
872 struct lc_element *e;
873 struct bm_extent *bm_ext;
874 int wakeup = 0;
875 unsigned long rs_flags;
876
877 spin_lock_irq(&mdev->al_lock);
878 if (mdev->resync_locked > mdev->resync->nr_elements/2) {
879 spin_unlock_irq(&mdev->al_lock);
880 return NULL;
881 }
882 e = lc_get(mdev->resync, enr);
883 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
884 if (bm_ext) {
885 if (bm_ext->lce.lc_number != enr) {
886 bm_ext->rs_left = drbd_bm_e_weight(mdev, enr);
887 bm_ext->rs_failed = 0;
888 lc_changed(mdev->resync, &bm_ext->lce);
889 wakeup = 1;
890 }
891 if (bm_ext->lce.refcnt == 1)
892 mdev->resync_locked++;
893 set_bit(BME_NO_WRITES, &bm_ext->flags);
894 }
895 rs_flags = mdev->resync->flags;
896 spin_unlock_irq(&mdev->al_lock);
897 if (wakeup)
898 wake_up(&mdev->al_wait);
899
900 if (!bm_ext) {
901 if (rs_flags & LC_STARVING)
902 dev_warn(DEV, "Have to wait for element"
903 " (resync LRU too small?)\n");
904 BUG_ON(rs_flags & LC_DIRTY);
905 }
906
907 return bm_ext;
908}
909
910static int _is_in_al(struct drbd_conf *mdev, unsigned int enr)
911{
912 struct lc_element *al_ext;
913 int rv = 0;
914
915 spin_lock_irq(&mdev->al_lock);
916 if (unlikely(enr == mdev->act_log->new_number))
917 rv = 1;
918 else {
919 al_ext = lc_find(mdev->act_log, enr);
920 if (al_ext) {
921 if (al_ext->refcnt)
922 rv = 1;
923 }
924 }
925 spin_unlock_irq(&mdev->al_lock);
926
927 /*
928 if (unlikely(rv)) {
929 dev_info(DEV, "Delaying sync read until app's write is done\n");
930 }
931 */
932 return rv;
933}
934
935/**
936 * drbd_rs_begin_io() - Gets an extent in the resync LRU cache and sets it to BME_LOCKED
937 * @mdev: DRBD device.
938 * @sector: The sector number.
939 *
940 * This functions sleeps on al_wait. Returns 0 on success, -EINTR if interrupted.
941 */
942int drbd_rs_begin_io(struct drbd_conf *mdev, sector_t sector)
943{
944 unsigned int enr = BM_SECT_TO_EXT(sector);
945 struct bm_extent *bm_ext;
946 int i, sig;
947 int sa = 200; /* Step aside 200 times, then grab the extent and let app-IO wait.
948 200 times -> 20 seconds. */
949
950retry:
951 sig = wait_event_interruptible(mdev->al_wait,
952 (bm_ext = _bme_get(mdev, enr)));
953 if (sig)
954 return -EINTR;
955
956 if (test_bit(BME_LOCKED, &bm_ext->flags))
957 return 0;
958
959 for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
960 sig = wait_event_interruptible(mdev->al_wait,
961 !_is_in_al(mdev, enr * AL_EXT_PER_BM_SECT + i) ||
962 test_bit(BME_PRIORITY, &bm_ext->flags));
963
964 if (sig || (test_bit(BME_PRIORITY, &bm_ext->flags) && sa)) {
965 spin_lock_irq(&mdev->al_lock);
966 if (lc_put(mdev->resync, &bm_ext->lce) == 0) {
967 bm_ext->flags = 0; /* clears BME_NO_WRITES and eventually BME_PRIORITY */
968 mdev->resync_locked--;
969 wake_up(&mdev->al_wait);
970 }
971 spin_unlock_irq(&mdev->al_lock);
972 if (sig)
973 return -EINTR;
974 if (schedule_timeout_interruptible(HZ/10))
975 return -EINTR;
976 if (sa && --sa == 0)
977 dev_warn(DEV,"drbd_rs_begin_io() stepped aside for 20sec."
978 "Resync stalled?\n");
979 goto retry;
980 }
981 }
982 set_bit(BME_LOCKED, &bm_ext->flags);
983 return 0;
984}
985
986/**
987 * drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep
988 * @mdev: DRBD device.
989 * @sector: The sector number.
990 *
991 * Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then
992 * tries to set it to BME_LOCKED. Returns 0 upon success, and -EAGAIN
993 * if there is still application IO going on in this area.
994 */
995int drbd_try_rs_begin_io(struct drbd_conf *mdev, sector_t sector)
996{
997 unsigned int enr = BM_SECT_TO_EXT(sector);
998 const unsigned int al_enr = enr*AL_EXT_PER_BM_SECT;
999 struct lc_element *e;
1000 struct bm_extent *bm_ext;
1001 int i;
1002
1003 spin_lock_irq(&mdev->al_lock);
1004 if (mdev->resync_wenr != LC_FREE && mdev->resync_wenr != enr) {
1005 /* in case you have very heavy scattered io, it may
1006 * stall the syncer undefined if we give up the ref count
1007 * when we try again and requeue.
1008 *
1009 * if we don't give up the refcount, but the next time
1010 * we are scheduled this extent has been "synced" by new
1011 * application writes, we'd miss the lc_put on the
1012 * extent we keep the refcount on.
1013 * so we remembered which extent we had to try again, and
1014 * if the next requested one is something else, we do
1015 * the lc_put here...
1016 * we also have to wake_up
1017 */
1018 e = lc_find(mdev->resync, mdev->resync_wenr);
1019 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1020 if (bm_ext) {
1021 D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
1022 D_ASSERT(test_bit(BME_NO_WRITES, &bm_ext->flags));
1023 clear_bit(BME_NO_WRITES, &bm_ext->flags);
1024 mdev->resync_wenr = LC_FREE;
1025 if (lc_put(mdev->resync, &bm_ext->lce) == 0)
1026 mdev->resync_locked--;
1027 wake_up(&mdev->al_wait);
1028 } else {
1029 dev_alert(DEV, "LOGIC BUG\n");
1030 }
1031 }
1032 /* TRY. */
1033 e = lc_try_get(mdev->resync, enr);
1034 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1035 if (bm_ext) {
1036 if (test_bit(BME_LOCKED, &bm_ext->flags))
1037 goto proceed;
1038 if (!test_and_set_bit(BME_NO_WRITES, &bm_ext->flags)) {
1039 mdev->resync_locked++;
1040 } else {
1041 /* we did set the BME_NO_WRITES,
1042 * but then could not set BME_LOCKED,
1043 * so we tried again.
1044 * drop the extra reference. */
1045 bm_ext->lce.refcnt--;
1046 D_ASSERT(bm_ext->lce.refcnt > 0);
1047 }
1048 goto check_al;
1049 } else {
1050 /* do we rather want to try later? */
1051 if (mdev->resync_locked > mdev->resync->nr_elements-3)
1052 goto try_again;
1053 /* Do or do not. There is no try. -- Yoda */
1054 e = lc_get(mdev->resync, enr);
1055 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1056 if (!bm_ext) {
1057 const unsigned long rs_flags = mdev->resync->flags;
1058 if (rs_flags & LC_STARVING)
1059 dev_warn(DEV, "Have to wait for element"
1060 " (resync LRU too small?)\n");
1061 BUG_ON(rs_flags & LC_DIRTY);
1062 goto try_again;
1063 }
1064 if (bm_ext->lce.lc_number != enr) {
1065 bm_ext->rs_left = drbd_bm_e_weight(mdev, enr);
1066 bm_ext->rs_failed = 0;
1067 lc_changed(mdev->resync, &bm_ext->lce);
1068 wake_up(&mdev->al_wait);
1069 D_ASSERT(test_bit(BME_LOCKED, &bm_ext->flags) == 0);
1070 }
1071 set_bit(BME_NO_WRITES, &bm_ext->flags);
1072 D_ASSERT(bm_ext->lce.refcnt == 1);
1073 mdev->resync_locked++;
1074 goto check_al;
1075 }
1076check_al:
1077 for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
1078 if (unlikely(al_enr+i == mdev->act_log->new_number))
1079 goto try_again;
1080 if (lc_is_used(mdev->act_log, al_enr+i))
1081 goto try_again;
1082 }
1083 set_bit(BME_LOCKED, &bm_ext->flags);
1084proceed:
1085 mdev->resync_wenr = LC_FREE;
1086 spin_unlock_irq(&mdev->al_lock);
1087 return 0;
1088
1089try_again:
1090 if (bm_ext)
1091 mdev->resync_wenr = enr;
1092 spin_unlock_irq(&mdev->al_lock);
1093 return -EAGAIN;
1094}
1095
1096void drbd_rs_complete_io(struct drbd_conf *mdev, sector_t sector)
1097{
1098 unsigned int enr = BM_SECT_TO_EXT(sector);
1099 struct lc_element *e;
1100 struct bm_extent *bm_ext;
1101 unsigned long flags;
1102
1103 spin_lock_irqsave(&mdev->al_lock, flags);
1104 e = lc_find(mdev->resync, enr);
1105 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1106 if (!bm_ext) {
1107 spin_unlock_irqrestore(&mdev->al_lock, flags);
1108 if (__ratelimit(&drbd_ratelimit_state))
1109 dev_err(DEV, "drbd_rs_complete_io() called, but extent not found\n");
1110 return;
1111 }
1112
1113 if (bm_ext->lce.refcnt == 0) {
1114 spin_unlock_irqrestore(&mdev->al_lock, flags);
1115 dev_err(DEV, "drbd_rs_complete_io(,%llu [=%u]) called, "
1116 "but refcnt is 0!?\n",
1117 (unsigned long long)sector, enr);
1118 return;
1119 }
1120
1121 if (lc_put(mdev->resync, &bm_ext->lce) == 0) {
1122 bm_ext->flags = 0; /* clear BME_LOCKED, BME_NO_WRITES and BME_PRIORITY */
1123 mdev->resync_locked--;
1124 wake_up(&mdev->al_wait);
1125 }
1126
1127 spin_unlock_irqrestore(&mdev->al_lock, flags);
1128}
1129
1130/**
1131 * drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED)
1132 * @mdev: DRBD device.
1133 */
1134void drbd_rs_cancel_all(struct drbd_conf *mdev)
1135{
1136 spin_lock_irq(&mdev->al_lock);
1137
1138 if (get_ldev_if_state(mdev, D_FAILED)) { /* Makes sure ->resync is there. */
1139 lc_reset(mdev->resync);
1140 put_ldev(mdev);
1141 }
1142 mdev->resync_locked = 0;
1143 mdev->resync_wenr = LC_FREE;
1144 spin_unlock_irq(&mdev->al_lock);
1145 wake_up(&mdev->al_wait);
1146}
1147
1148/**
1149 * drbd_rs_del_all() - Gracefully remove all extents from the resync LRU
1150 * @mdev: DRBD device.
1151 *
1152 * Returns 0 upon success, -EAGAIN if at least one reference count was
1153 * not zero.
1154 */
1155int drbd_rs_del_all(struct drbd_conf *mdev)
1156{
1157 struct lc_element *e;
1158 struct bm_extent *bm_ext;
1159 int i;
1160
1161 spin_lock_irq(&mdev->al_lock);
1162
1163 if (get_ldev_if_state(mdev, D_FAILED)) {
1164 /* ok, ->resync is there. */
1165 for (i = 0; i < mdev->resync->nr_elements; i++) {
1166 e = lc_element_by_index(mdev->resync, i);
1167 bm_ext = lc_entry(e, struct bm_extent, lce);
1168 if (bm_ext->lce.lc_number == LC_FREE)
1169 continue;
1170 if (bm_ext->lce.lc_number == mdev->resync_wenr) {
1171 dev_info(DEV, "dropping %u in drbd_rs_del_all, apparently"
1172 " got 'synced' by application io\n",
1173 mdev->resync_wenr);
1174 D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
1175 D_ASSERT(test_bit(BME_NO_WRITES, &bm_ext->flags));
1176 clear_bit(BME_NO_WRITES, &bm_ext->flags);
1177 mdev->resync_wenr = LC_FREE;
1178 lc_put(mdev->resync, &bm_ext->lce);
1179 }
1180 if (bm_ext->lce.refcnt != 0) {
1181 dev_info(DEV, "Retrying drbd_rs_del_all() later. "
1182 "refcnt=%d\n", bm_ext->lce.refcnt);
1183 put_ldev(mdev);
1184 spin_unlock_irq(&mdev->al_lock);
1185 return -EAGAIN;
1186 }
1187 D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
1188 D_ASSERT(!test_bit(BME_NO_WRITES, &bm_ext->flags));
1189 lc_del(mdev->resync, &bm_ext->lce);
1190 }
1191 D_ASSERT(mdev->resync->used == 0);
1192 put_ldev(mdev);
1193 }
1194 spin_unlock_irq(&mdev->al_lock);
1195
1196 return 0;
1197}
1198
1199/**
1200 * drbd_rs_failed_io() - Record information on a failure to resync the specified blocks
1201 * @mdev: DRBD device.
1202 * @sector: The sector number.
1203 * @size: Size of failed IO operation, in byte.
1204 */
1205void drbd_rs_failed_io(struct drbd_conf *mdev, sector_t sector, int size)
1206{
1207 /* Is called from worker and receiver context _only_ */
1208 unsigned long sbnr, ebnr, lbnr;
1209 unsigned long count;
1210 sector_t esector, nr_sectors;
1211 int wake_up = 0;
1212
1213 if (size <= 0 || (size & 0x1ff) != 0 || size > DRBD_MAX_BIO_SIZE) {
1214 dev_err(DEV, "drbd_rs_failed_io: sector=%llus size=%d nonsense!\n",
1215 (unsigned long long)sector, size);
1216 return;
1217 }
1218 nr_sectors = drbd_get_capacity(mdev->this_bdev);
1219 esector = sector + (size >> 9) - 1;
1220
1221 ERR_IF(sector >= nr_sectors) return;
1222 ERR_IF(esector >= nr_sectors) esector = (nr_sectors-1);
1223
1224 lbnr = BM_SECT_TO_BIT(nr_sectors-1);
1225
1226 /*
1227 * round up start sector, round down end sector. we make sure we only
1228 * handle full, aligned, BM_BLOCK_SIZE (4K) blocks */
1229 if (unlikely(esector < BM_SECT_PER_BIT-1))
1230 return;
1231 if (unlikely(esector == (nr_sectors-1)))
1232 ebnr = lbnr;
1233 else
1234 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
1235 sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
1236
1237 if (sbnr > ebnr)
1238 return;
1239
1240 /*
1241 * ok, (capacity & 7) != 0 sometimes, but who cares...
1242 * we count rs_{total,left} in bits, not sectors.
1243 */
1244 spin_lock_irq(&mdev->al_lock);
1245 count = drbd_bm_count_bits(mdev, sbnr, ebnr);
1246 if (count) {
1247 mdev->rs_failed += count;
1248
1249 if (get_ldev(mdev)) {
1250 drbd_try_clear_on_disk_bm(mdev, sector, count, false);
1251 put_ldev(mdev);
1252 }
1253
1254 /* just wake_up unconditional now, various lc_chaged(),
1255 * lc_put() in drbd_try_clear_on_disk_bm(). */
1256 wake_up = 1;
1257 }
1258 spin_unlock_irq(&mdev->al_lock);
1259 if (wake_up)
1260 wake_up(&mdev->al_wait);
1261}
1/*
2 drbd_actlog.c
3
4 This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
5
6 Copyright (C) 2003-2008, LINBIT Information Technologies GmbH.
7 Copyright (C) 2003-2008, Philipp Reisner <philipp.reisner@linbit.com>.
8 Copyright (C) 2003-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
9
10 drbd is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 2, or (at your option)
13 any later version.
14
15 drbd is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
19
20 You should have received a copy of the GNU General Public License
21 along with drbd; see the file COPYING. If not, write to
22 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
23
24 */
25
26#include <linux/slab.h>
27#include <linux/crc32c.h>
28#include <linux/drbd.h>
29#include <linux/drbd_limits.h>
30#include "drbd_int.h"
31
32
33enum al_transaction_types {
34 AL_TR_UPDATE = 0,
35 AL_TR_INITIALIZED = 0xffff
36};
37/* all fields on disc in big endian */
38struct __packed al_transaction_on_disk {
39 /* don't we all like magic */
40 __be32 magic;
41
42 /* to identify the most recent transaction block
43 * in the on disk ring buffer */
44 __be32 tr_number;
45
46 /* checksum on the full 4k block, with this field set to 0. */
47 __be32 crc32c;
48
49 /* type of transaction, special transaction types like:
50 * purge-all, set-all-idle, set-all-active, ... to-be-defined
51 * see also enum al_transaction_types */
52 __be16 transaction_type;
53
54 /* we currently allow only a few thousand extents,
55 * so 16bit will be enough for the slot number. */
56
57 /* how many updates in this transaction */
58 __be16 n_updates;
59
60 /* maximum slot number, "al-extents" in drbd.conf speak.
61 * Having this in each transaction should make reconfiguration
62 * of that parameter easier. */
63 __be16 context_size;
64
65 /* slot number the context starts with */
66 __be16 context_start_slot_nr;
67
68 /* Some reserved bytes. Expected usage is a 64bit counter of
69 * sectors-written since device creation, and other data generation tag
70 * supporting usage */
71 __be32 __reserved[4];
72
73 /* --- 36 byte used --- */
74
75 /* Reserve space for up to AL_UPDATES_PER_TRANSACTION changes
76 * in one transaction, then use the remaining byte in the 4k block for
77 * context information. "Flexible" number of updates per transaction
78 * does not help, as we have to account for the case when all update
79 * slots are used anyways, so it would only complicate code without
80 * additional benefit.
81 */
82 __be16 update_slot_nr[AL_UPDATES_PER_TRANSACTION];
83
84 /* but the extent number is 32bit, which at an extent size of 4 MiB
85 * allows to cover device sizes of up to 2**54 Byte (16 PiB) */
86 __be32 update_extent_nr[AL_UPDATES_PER_TRANSACTION];
87
88 /* --- 420 bytes used (36 + 64*6) --- */
89
90 /* 4096 - 420 = 3676 = 919 * 4 */
91 __be32 context[AL_CONTEXT_PER_TRANSACTION];
92};
93
94void *drbd_md_get_buffer(struct drbd_device *device, const char *intent)
95{
96 int r;
97
98 wait_event(device->misc_wait,
99 (r = atomic_cmpxchg(&device->md_io.in_use, 0, 1)) == 0 ||
100 device->state.disk <= D_FAILED);
101
102 if (r)
103 return NULL;
104
105 device->md_io.current_use = intent;
106 device->md_io.start_jif = jiffies;
107 device->md_io.submit_jif = device->md_io.start_jif - 1;
108 return page_address(device->md_io.page);
109}
110
111void drbd_md_put_buffer(struct drbd_device *device)
112{
113 if (atomic_dec_and_test(&device->md_io.in_use))
114 wake_up(&device->misc_wait);
115}
116
117void wait_until_done_or_force_detached(struct drbd_device *device, struct drbd_backing_dev *bdev,
118 unsigned int *done)
119{
120 long dt;
121
122 rcu_read_lock();
123 dt = rcu_dereference(bdev->disk_conf)->disk_timeout;
124 rcu_read_unlock();
125 dt = dt * HZ / 10;
126 if (dt == 0)
127 dt = MAX_SCHEDULE_TIMEOUT;
128
129 dt = wait_event_timeout(device->misc_wait,
130 *done || test_bit(FORCE_DETACH, &device->flags), dt);
131 if (dt == 0) {
132 drbd_err(device, "meta-data IO operation timed out\n");
133 drbd_chk_io_error(device, 1, DRBD_FORCE_DETACH);
134 }
135}
136
137static int _drbd_md_sync_page_io(struct drbd_device *device,
138 struct drbd_backing_dev *bdev,
139 sector_t sector, int op)
140{
141 struct bio *bio;
142 /* we do all our meta data IO in aligned 4k blocks. */
143 const int size = 4096;
144 int err, op_flags = 0;
145
146 device->md_io.done = 0;
147 device->md_io.error = -ENODEV;
148
149 if ((op == REQ_OP_WRITE) && !test_bit(MD_NO_FUA, &device->flags))
150 op_flags |= REQ_FUA | REQ_PREFLUSH;
151 op_flags |= REQ_SYNC;
152
153 bio = bio_alloc_drbd(GFP_NOIO);
154 bio_set_dev(bio, bdev->md_bdev);
155 bio->bi_iter.bi_sector = sector;
156 err = -EIO;
157 if (bio_add_page(bio, device->md_io.page, size, 0) != size)
158 goto out;
159 bio->bi_private = device;
160 bio->bi_end_io = drbd_md_endio;
161 bio_set_op_attrs(bio, op, op_flags);
162
163 if (op != REQ_OP_WRITE && device->state.disk == D_DISKLESS && device->ldev == NULL)
164 /* special case, drbd_md_read() during drbd_adm_attach(): no get_ldev */
165 ;
166 else if (!get_ldev_if_state(device, D_ATTACHING)) {
167 /* Corresponding put_ldev in drbd_md_endio() */
168 drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in _drbd_md_sync_page_io()\n");
169 err = -ENODEV;
170 goto out;
171 }
172
173 bio_get(bio); /* one bio_put() is in the completion handler */
174 atomic_inc(&device->md_io.in_use); /* drbd_md_put_buffer() is in the completion handler */
175 device->md_io.submit_jif = jiffies;
176 if (drbd_insert_fault(device, (op == REQ_OP_WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD))
177 bio_io_error(bio);
178 else
179 submit_bio(bio);
180 wait_until_done_or_force_detached(device, bdev, &device->md_io.done);
181 if (!bio->bi_status)
182 err = device->md_io.error;
183
184 out:
185 bio_put(bio);
186 return err;
187}
188
189int drbd_md_sync_page_io(struct drbd_device *device, struct drbd_backing_dev *bdev,
190 sector_t sector, int op)
191{
192 int err;
193 D_ASSERT(device, atomic_read(&device->md_io.in_use) == 1);
194
195 BUG_ON(!bdev->md_bdev);
196
197 dynamic_drbd_dbg(device, "meta_data io: %s [%d]:%s(,%llus,%s) %pS\n",
198 current->comm, current->pid, __func__,
199 (unsigned long long)sector, (op == REQ_OP_WRITE) ? "WRITE" : "READ",
200 (void*)_RET_IP_ );
201
202 if (sector < drbd_md_first_sector(bdev) ||
203 sector + 7 > drbd_md_last_sector(bdev))
204 drbd_alert(device, "%s [%d]:%s(,%llus,%s) out of range md access!\n",
205 current->comm, current->pid, __func__,
206 (unsigned long long)sector,
207 (op == REQ_OP_WRITE) ? "WRITE" : "READ");
208
209 err = _drbd_md_sync_page_io(device, bdev, sector, op);
210 if (err) {
211 drbd_err(device, "drbd_md_sync_page_io(,%llus,%s) failed with error %d\n",
212 (unsigned long long)sector,
213 (op == REQ_OP_WRITE) ? "WRITE" : "READ", err);
214 }
215 return err;
216}
217
218static struct bm_extent *find_active_resync_extent(struct drbd_device *device, unsigned int enr)
219{
220 struct lc_element *tmp;
221 tmp = lc_find(device->resync, enr/AL_EXT_PER_BM_SECT);
222 if (unlikely(tmp != NULL)) {
223 struct bm_extent *bm_ext = lc_entry(tmp, struct bm_extent, lce);
224 if (test_bit(BME_NO_WRITES, &bm_ext->flags))
225 return bm_ext;
226 }
227 return NULL;
228}
229
230static struct lc_element *_al_get(struct drbd_device *device, unsigned int enr, bool nonblock)
231{
232 struct lc_element *al_ext;
233 struct bm_extent *bm_ext;
234 int wake;
235
236 spin_lock_irq(&device->al_lock);
237 bm_ext = find_active_resync_extent(device, enr);
238 if (bm_ext) {
239 wake = !test_and_set_bit(BME_PRIORITY, &bm_ext->flags);
240 spin_unlock_irq(&device->al_lock);
241 if (wake)
242 wake_up(&device->al_wait);
243 return NULL;
244 }
245 if (nonblock)
246 al_ext = lc_try_get(device->act_log, enr);
247 else
248 al_ext = lc_get(device->act_log, enr);
249 spin_unlock_irq(&device->al_lock);
250 return al_ext;
251}
252
253bool drbd_al_begin_io_fastpath(struct drbd_device *device, struct drbd_interval *i)
254{
255 /* for bios crossing activity log extent boundaries,
256 * we may need to activate two extents in one go */
257 unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
258 unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
259
260 D_ASSERT(device, first <= last);
261 D_ASSERT(device, atomic_read(&device->local_cnt) > 0);
262
263 /* FIXME figure out a fast path for bios crossing AL extent boundaries */
264 if (first != last)
265 return false;
266
267 return _al_get(device, first, true);
268}
269
270bool drbd_al_begin_io_prepare(struct drbd_device *device, struct drbd_interval *i)
271{
272 /* for bios crossing activity log extent boundaries,
273 * we may need to activate two extents in one go */
274 unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
275 unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
276 unsigned enr;
277 bool need_transaction = false;
278
279 D_ASSERT(device, first <= last);
280 D_ASSERT(device, atomic_read(&device->local_cnt) > 0);
281
282 for (enr = first; enr <= last; enr++) {
283 struct lc_element *al_ext;
284 wait_event(device->al_wait,
285 (al_ext = _al_get(device, enr, false)) != NULL);
286 if (al_ext->lc_number != enr)
287 need_transaction = true;
288 }
289 return need_transaction;
290}
291
292#if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)
293/* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT
294 * are still coupled, or assume too much about their relation.
295 * Code below will not work if this is violated.
296 * Will be cleaned up with some followup patch.
297 */
298# error FIXME
299#endif
300
301static unsigned int al_extent_to_bm_page(unsigned int al_enr)
302{
303 return al_enr >>
304 /* bit to page */
305 ((PAGE_SHIFT + 3) -
306 /* al extent number to bit */
307 (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT));
308}
309
310static sector_t al_tr_number_to_on_disk_sector(struct drbd_device *device)
311{
312 const unsigned int stripes = device->ldev->md.al_stripes;
313 const unsigned int stripe_size_4kB = device->ldev->md.al_stripe_size_4k;
314
315 /* transaction number, modulo on-disk ring buffer wrap around */
316 unsigned int t = device->al_tr_number % (device->ldev->md.al_size_4k);
317
318 /* ... to aligned 4k on disk block */
319 t = ((t % stripes) * stripe_size_4kB) + t/stripes;
320
321 /* ... to 512 byte sector in activity log */
322 t *= 8;
323
324 /* ... plus offset to the on disk position */
325 return device->ldev->md.md_offset + device->ldev->md.al_offset + t;
326}
327
328static int __al_write_transaction(struct drbd_device *device, struct al_transaction_on_disk *buffer)
329{
330 struct lc_element *e;
331 sector_t sector;
332 int i, mx;
333 unsigned extent_nr;
334 unsigned crc = 0;
335 int err = 0;
336
337 memset(buffer, 0, sizeof(*buffer));
338 buffer->magic = cpu_to_be32(DRBD_AL_MAGIC);
339 buffer->tr_number = cpu_to_be32(device->al_tr_number);
340
341 i = 0;
342
343 drbd_bm_reset_al_hints(device);
344
345 /* Even though no one can start to change this list
346 * once we set the LC_LOCKED -- from drbd_al_begin_io(),
347 * lc_try_lock_for_transaction() --, someone may still
348 * be in the process of changing it. */
349 spin_lock_irq(&device->al_lock);
350 list_for_each_entry(e, &device->act_log->to_be_changed, list) {
351 if (i == AL_UPDATES_PER_TRANSACTION) {
352 i++;
353 break;
354 }
355 buffer->update_slot_nr[i] = cpu_to_be16(e->lc_index);
356 buffer->update_extent_nr[i] = cpu_to_be32(e->lc_new_number);
357 if (e->lc_number != LC_FREE)
358 drbd_bm_mark_for_writeout(device,
359 al_extent_to_bm_page(e->lc_number));
360 i++;
361 }
362 spin_unlock_irq(&device->al_lock);
363 BUG_ON(i > AL_UPDATES_PER_TRANSACTION);
364
365 buffer->n_updates = cpu_to_be16(i);
366 for ( ; i < AL_UPDATES_PER_TRANSACTION; i++) {
367 buffer->update_slot_nr[i] = cpu_to_be16(-1);
368 buffer->update_extent_nr[i] = cpu_to_be32(LC_FREE);
369 }
370
371 buffer->context_size = cpu_to_be16(device->act_log->nr_elements);
372 buffer->context_start_slot_nr = cpu_to_be16(device->al_tr_cycle);
373
374 mx = min_t(int, AL_CONTEXT_PER_TRANSACTION,
375 device->act_log->nr_elements - device->al_tr_cycle);
376 for (i = 0; i < mx; i++) {
377 unsigned idx = device->al_tr_cycle + i;
378 extent_nr = lc_element_by_index(device->act_log, idx)->lc_number;
379 buffer->context[i] = cpu_to_be32(extent_nr);
380 }
381 for (; i < AL_CONTEXT_PER_TRANSACTION; i++)
382 buffer->context[i] = cpu_to_be32(LC_FREE);
383
384 device->al_tr_cycle += AL_CONTEXT_PER_TRANSACTION;
385 if (device->al_tr_cycle >= device->act_log->nr_elements)
386 device->al_tr_cycle = 0;
387
388 sector = al_tr_number_to_on_disk_sector(device);
389
390 crc = crc32c(0, buffer, 4096);
391 buffer->crc32c = cpu_to_be32(crc);
392
393 if (drbd_bm_write_hinted(device))
394 err = -EIO;
395 else {
396 bool write_al_updates;
397 rcu_read_lock();
398 write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
399 rcu_read_unlock();
400 if (write_al_updates) {
401 if (drbd_md_sync_page_io(device, device->ldev, sector, WRITE)) {
402 err = -EIO;
403 drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR);
404 } else {
405 device->al_tr_number++;
406 device->al_writ_cnt++;
407 }
408 }
409 }
410
411 return err;
412}
413
414static int al_write_transaction(struct drbd_device *device)
415{
416 struct al_transaction_on_disk *buffer;
417 int err;
418
419 if (!get_ldev(device)) {
420 drbd_err(device, "disk is %s, cannot start al transaction\n",
421 drbd_disk_str(device->state.disk));
422 return -EIO;
423 }
424
425 /* The bitmap write may have failed, causing a state change. */
426 if (device->state.disk < D_INCONSISTENT) {
427 drbd_err(device,
428 "disk is %s, cannot write al transaction\n",
429 drbd_disk_str(device->state.disk));
430 put_ldev(device);
431 return -EIO;
432 }
433
434 /* protects md_io_buffer, al_tr_cycle, ... */
435 buffer = drbd_md_get_buffer(device, __func__);
436 if (!buffer) {
437 drbd_err(device, "disk failed while waiting for md_io buffer\n");
438 put_ldev(device);
439 return -ENODEV;
440 }
441
442 err = __al_write_transaction(device, buffer);
443
444 drbd_md_put_buffer(device);
445 put_ldev(device);
446
447 return err;
448}
449
450
451void drbd_al_begin_io_commit(struct drbd_device *device)
452{
453 bool locked = false;
454
455 /* Serialize multiple transactions.
456 * This uses test_and_set_bit, memory barrier is implicit.
457 */
458 wait_event(device->al_wait,
459 device->act_log->pending_changes == 0 ||
460 (locked = lc_try_lock_for_transaction(device->act_log)));
461
462 if (locked) {
463 /* Double check: it may have been committed by someone else,
464 * while we have been waiting for the lock. */
465 if (device->act_log->pending_changes) {
466 bool write_al_updates;
467
468 rcu_read_lock();
469 write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
470 rcu_read_unlock();
471
472 if (write_al_updates)
473 al_write_transaction(device);
474 spin_lock_irq(&device->al_lock);
475 /* FIXME
476 if (err)
477 we need an "lc_cancel" here;
478 */
479 lc_committed(device->act_log);
480 spin_unlock_irq(&device->al_lock);
481 }
482 lc_unlock(device->act_log);
483 wake_up(&device->al_wait);
484 }
485}
486
487/*
488 * @delegate: delegate activity log I/O to the worker thread
489 */
490void drbd_al_begin_io(struct drbd_device *device, struct drbd_interval *i)
491{
492 if (drbd_al_begin_io_prepare(device, i))
493 drbd_al_begin_io_commit(device);
494}
495
496int drbd_al_begin_io_nonblock(struct drbd_device *device, struct drbd_interval *i)
497{
498 struct lru_cache *al = device->act_log;
499 /* for bios crossing activity log extent boundaries,
500 * we may need to activate two extents in one go */
501 unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
502 unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
503 unsigned nr_al_extents;
504 unsigned available_update_slots;
505 unsigned enr;
506
507 D_ASSERT(device, first <= last);
508
509 nr_al_extents = 1 + last - first; /* worst case: all touched extends are cold. */
510 available_update_slots = min(al->nr_elements - al->used,
511 al->max_pending_changes - al->pending_changes);
512
513 /* We want all necessary updates for a given request within the same transaction
514 * We could first check how many updates are *actually* needed,
515 * and use that instead of the worst-case nr_al_extents */
516 if (available_update_slots < nr_al_extents) {
517 /* Too many activity log extents are currently "hot".
518 *
519 * If we have accumulated pending changes already,
520 * we made progress.
521 *
522 * If we cannot get even a single pending change through,
523 * stop the fast path until we made some progress,
524 * or requests to "cold" extents could be starved. */
525 if (!al->pending_changes)
526 __set_bit(__LC_STARVING, &device->act_log->flags);
527 return -ENOBUFS;
528 }
529
530 /* Is resync active in this area? */
531 for (enr = first; enr <= last; enr++) {
532 struct lc_element *tmp;
533 tmp = lc_find(device->resync, enr/AL_EXT_PER_BM_SECT);
534 if (unlikely(tmp != NULL)) {
535 struct bm_extent *bm_ext = lc_entry(tmp, struct bm_extent, lce);
536 if (test_bit(BME_NO_WRITES, &bm_ext->flags)) {
537 if (!test_and_set_bit(BME_PRIORITY, &bm_ext->flags))
538 return -EBUSY;
539 return -EWOULDBLOCK;
540 }
541 }
542 }
543
544 /* Checkout the refcounts.
545 * Given that we checked for available elements and update slots above,
546 * this has to be successful. */
547 for (enr = first; enr <= last; enr++) {
548 struct lc_element *al_ext;
549 al_ext = lc_get_cumulative(device->act_log, enr);
550 if (!al_ext)
551 drbd_info(device, "LOGIC BUG for enr=%u\n", enr);
552 }
553 return 0;
554}
555
556void drbd_al_complete_io(struct drbd_device *device, struct drbd_interval *i)
557{
558 /* for bios crossing activity log extent boundaries,
559 * we may need to activate two extents in one go */
560 unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
561 unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
562 unsigned enr;
563 struct lc_element *extent;
564 unsigned long flags;
565
566 D_ASSERT(device, first <= last);
567 spin_lock_irqsave(&device->al_lock, flags);
568
569 for (enr = first; enr <= last; enr++) {
570 extent = lc_find(device->act_log, enr);
571 if (!extent) {
572 drbd_err(device, "al_complete_io() called on inactive extent %u\n", enr);
573 continue;
574 }
575 lc_put(device->act_log, extent);
576 }
577 spin_unlock_irqrestore(&device->al_lock, flags);
578 wake_up(&device->al_wait);
579}
580
581static int _try_lc_del(struct drbd_device *device, struct lc_element *al_ext)
582{
583 int rv;
584
585 spin_lock_irq(&device->al_lock);
586 rv = (al_ext->refcnt == 0);
587 if (likely(rv))
588 lc_del(device->act_log, al_ext);
589 spin_unlock_irq(&device->al_lock);
590
591 return rv;
592}
593
594/**
595 * drbd_al_shrink() - Removes all active extents form the activity log
596 * @device: DRBD device.
597 *
598 * Removes all active extents form the activity log, waiting until
599 * the reference count of each entry dropped to 0 first, of course.
600 *
601 * You need to lock device->act_log with lc_try_lock() / lc_unlock()
602 */
603void drbd_al_shrink(struct drbd_device *device)
604{
605 struct lc_element *al_ext;
606 int i;
607
608 D_ASSERT(device, test_bit(__LC_LOCKED, &device->act_log->flags));
609
610 for (i = 0; i < device->act_log->nr_elements; i++) {
611 al_ext = lc_element_by_index(device->act_log, i);
612 if (al_ext->lc_number == LC_FREE)
613 continue;
614 wait_event(device->al_wait, _try_lc_del(device, al_ext));
615 }
616
617 wake_up(&device->al_wait);
618}
619
620int drbd_al_initialize(struct drbd_device *device, void *buffer)
621{
622 struct al_transaction_on_disk *al = buffer;
623 struct drbd_md *md = &device->ldev->md;
624 int al_size_4k = md->al_stripes * md->al_stripe_size_4k;
625 int i;
626
627 __al_write_transaction(device, al);
628 /* There may or may not have been a pending transaction. */
629 spin_lock_irq(&device->al_lock);
630 lc_committed(device->act_log);
631 spin_unlock_irq(&device->al_lock);
632
633 /* The rest of the transactions will have an empty "updates" list, and
634 * are written out only to provide the context, and to initialize the
635 * on-disk ring buffer. */
636 for (i = 1; i < al_size_4k; i++) {
637 int err = __al_write_transaction(device, al);
638 if (err)
639 return err;
640 }
641 return 0;
642}
643
644static const char *drbd_change_sync_fname[] = {
645 [RECORD_RS_FAILED] = "drbd_rs_failed_io",
646 [SET_IN_SYNC] = "drbd_set_in_sync",
647 [SET_OUT_OF_SYNC] = "drbd_set_out_of_sync"
648};
649
650/* ATTENTION. The AL's extents are 4MB each, while the extents in the
651 * resync LRU-cache are 16MB each.
652 * The caller of this function has to hold an get_ldev() reference.
653 *
654 * Adjusts the caching members ->rs_left (success) or ->rs_failed (!success),
655 * potentially pulling in (and recounting the corresponding bits)
656 * this resync extent into the resync extent lru cache.
657 *
658 * Returns whether all bits have been cleared for this resync extent,
659 * precisely: (rs_left <= rs_failed)
660 *
661 * TODO will be obsoleted once we have a caching lru of the on disk bitmap
662 */
663static bool update_rs_extent(struct drbd_device *device,
664 unsigned int enr, int count,
665 enum update_sync_bits_mode mode)
666{
667 struct lc_element *e;
668
669 D_ASSERT(device, atomic_read(&device->local_cnt));
670
671 /* When setting out-of-sync bits,
672 * we don't need it cached (lc_find).
673 * But if it is present in the cache,
674 * we should update the cached bit count.
675 * Otherwise, that extent should be in the resync extent lru cache
676 * already -- or we want to pull it in if necessary -- (lc_get),
677 * then update and check rs_left and rs_failed. */
678 if (mode == SET_OUT_OF_SYNC)
679 e = lc_find(device->resync, enr);
680 else
681 e = lc_get(device->resync, enr);
682 if (e) {
683 struct bm_extent *ext = lc_entry(e, struct bm_extent, lce);
684 if (ext->lce.lc_number == enr) {
685 if (mode == SET_IN_SYNC)
686 ext->rs_left -= count;
687 else if (mode == SET_OUT_OF_SYNC)
688 ext->rs_left += count;
689 else
690 ext->rs_failed += count;
691 if (ext->rs_left < ext->rs_failed) {
692 drbd_warn(device, "BAD! enr=%u rs_left=%d "
693 "rs_failed=%d count=%d cstate=%s\n",
694 ext->lce.lc_number, ext->rs_left,
695 ext->rs_failed, count,
696 drbd_conn_str(device->state.conn));
697
698 /* We don't expect to be able to clear more bits
699 * than have been set when we originally counted
700 * the set bits to cache that value in ext->rs_left.
701 * Whatever the reason (disconnect during resync,
702 * delayed local completion of an application write),
703 * try to fix it up by recounting here. */
704 ext->rs_left = drbd_bm_e_weight(device, enr);
705 }
706 } else {
707 /* Normally this element should be in the cache,
708 * since drbd_rs_begin_io() pulled it already in.
709 *
710 * But maybe an application write finished, and we set
711 * something outside the resync lru_cache in sync.
712 */
713 int rs_left = drbd_bm_e_weight(device, enr);
714 if (ext->flags != 0) {
715 drbd_warn(device, "changing resync lce: %d[%u;%02lx]"
716 " -> %d[%u;00]\n",
717 ext->lce.lc_number, ext->rs_left,
718 ext->flags, enr, rs_left);
719 ext->flags = 0;
720 }
721 if (ext->rs_failed) {
722 drbd_warn(device, "Kicking resync_lru element enr=%u "
723 "out with rs_failed=%d\n",
724 ext->lce.lc_number, ext->rs_failed);
725 }
726 ext->rs_left = rs_left;
727 ext->rs_failed = (mode == RECORD_RS_FAILED) ? count : 0;
728 /* we don't keep a persistent log of the resync lru,
729 * we can commit any change right away. */
730 lc_committed(device->resync);
731 }
732 if (mode != SET_OUT_OF_SYNC)
733 lc_put(device->resync, &ext->lce);
734 /* no race, we are within the al_lock! */
735
736 if (ext->rs_left <= ext->rs_failed) {
737 ext->rs_failed = 0;
738 return true;
739 }
740 } else if (mode != SET_OUT_OF_SYNC) {
741 /* be quiet if lc_find() did not find it. */
742 drbd_err(device, "lc_get() failed! locked=%d/%d flags=%lu\n",
743 device->resync_locked,
744 device->resync->nr_elements,
745 device->resync->flags);
746 }
747 return false;
748}
749
750void drbd_advance_rs_marks(struct drbd_device *device, unsigned long still_to_go)
751{
752 unsigned long now = jiffies;
753 unsigned long last = device->rs_mark_time[device->rs_last_mark];
754 int next = (device->rs_last_mark + 1) % DRBD_SYNC_MARKS;
755 if (time_after_eq(now, last + DRBD_SYNC_MARK_STEP)) {
756 if (device->rs_mark_left[device->rs_last_mark] != still_to_go &&
757 device->state.conn != C_PAUSED_SYNC_T &&
758 device->state.conn != C_PAUSED_SYNC_S) {
759 device->rs_mark_time[next] = now;
760 device->rs_mark_left[next] = still_to_go;
761 device->rs_last_mark = next;
762 }
763 }
764}
765
766/* It is called lazy update, so don't do write-out too often. */
767static bool lazy_bitmap_update_due(struct drbd_device *device)
768{
769 return time_after(jiffies, device->rs_last_bcast + 2*HZ);
770}
771
772static void maybe_schedule_on_disk_bitmap_update(struct drbd_device *device, bool rs_done)
773{
774 if (rs_done) {
775 struct drbd_connection *connection = first_peer_device(device)->connection;
776 if (connection->agreed_pro_version <= 95 ||
777 is_sync_target_state(device->state.conn))
778 set_bit(RS_DONE, &device->flags);
779 /* and also set RS_PROGRESS below */
780
781 /* Else: rather wait for explicit notification via receive_state,
782 * to avoid uuids-rotated-too-fast causing full resync
783 * in next handshake, in case the replication link breaks
784 * at the most unfortunate time... */
785 } else if (!lazy_bitmap_update_due(device))
786 return;
787
788 drbd_device_post_work(device, RS_PROGRESS);
789}
790
791static int update_sync_bits(struct drbd_device *device,
792 unsigned long sbnr, unsigned long ebnr,
793 enum update_sync_bits_mode mode)
794{
795 /*
796 * We keep a count of set bits per resync-extent in the ->rs_left
797 * caching member, so we need to loop and work within the resync extent
798 * alignment. Typically this loop will execute exactly once.
799 */
800 unsigned long flags;
801 unsigned long count = 0;
802 unsigned int cleared = 0;
803 while (sbnr <= ebnr) {
804 /* set temporary boundary bit number to last bit number within
805 * the resync extent of the current start bit number,
806 * but cap at provided end bit number */
807 unsigned long tbnr = min(ebnr, sbnr | BM_BLOCKS_PER_BM_EXT_MASK);
808 unsigned long c;
809
810 if (mode == RECORD_RS_FAILED)
811 /* Only called from drbd_rs_failed_io(), bits
812 * supposedly still set. Recount, maybe some
813 * of the bits have been successfully cleared
814 * by application IO meanwhile.
815 */
816 c = drbd_bm_count_bits(device, sbnr, tbnr);
817 else if (mode == SET_IN_SYNC)
818 c = drbd_bm_clear_bits(device, sbnr, tbnr);
819 else /* if (mode == SET_OUT_OF_SYNC) */
820 c = drbd_bm_set_bits(device, sbnr, tbnr);
821
822 if (c) {
823 spin_lock_irqsave(&device->al_lock, flags);
824 cleared += update_rs_extent(device, BM_BIT_TO_EXT(sbnr), c, mode);
825 spin_unlock_irqrestore(&device->al_lock, flags);
826 count += c;
827 }
828 sbnr = tbnr + 1;
829 }
830 if (count) {
831 if (mode == SET_IN_SYNC) {
832 unsigned long still_to_go = drbd_bm_total_weight(device);
833 bool rs_is_done = (still_to_go <= device->rs_failed);
834 drbd_advance_rs_marks(device, still_to_go);
835 if (cleared || rs_is_done)
836 maybe_schedule_on_disk_bitmap_update(device, rs_is_done);
837 } else if (mode == RECORD_RS_FAILED)
838 device->rs_failed += count;
839 wake_up(&device->al_wait);
840 }
841 return count;
842}
843
844static bool plausible_request_size(int size)
845{
846 return size > 0
847 && size <= DRBD_MAX_BATCH_BIO_SIZE
848 && IS_ALIGNED(size, 512);
849}
850
851/* clear the bit corresponding to the piece of storage in question:
852 * size byte of data starting from sector. Only clear a bits of the affected
853 * one ore more _aligned_ BM_BLOCK_SIZE blocks.
854 *
855 * called by worker on C_SYNC_TARGET and receiver on SyncSource.
856 *
857 */
858int __drbd_change_sync(struct drbd_device *device, sector_t sector, int size,
859 enum update_sync_bits_mode mode)
860{
861 /* Is called from worker and receiver context _only_ */
862 unsigned long sbnr, ebnr, lbnr;
863 unsigned long count = 0;
864 sector_t esector, nr_sectors;
865
866 /* This would be an empty REQ_PREFLUSH, be silent. */
867 if ((mode == SET_OUT_OF_SYNC) && size == 0)
868 return 0;
869
870 if (!plausible_request_size(size)) {
871 drbd_err(device, "%s: sector=%llus size=%d nonsense!\n",
872 drbd_change_sync_fname[mode],
873 (unsigned long long)sector, size);
874 return 0;
875 }
876
877 if (!get_ldev(device))
878 return 0; /* no disk, no metadata, no bitmap to manipulate bits in */
879
880 nr_sectors = drbd_get_capacity(device->this_bdev);
881 esector = sector + (size >> 9) - 1;
882
883 if (!expect(sector < nr_sectors))
884 goto out;
885 if (!expect(esector < nr_sectors))
886 esector = nr_sectors - 1;
887
888 lbnr = BM_SECT_TO_BIT(nr_sectors-1);
889
890 if (mode == SET_IN_SYNC) {
891 /* Round up start sector, round down end sector. We make sure
892 * we only clear full, aligned, BM_BLOCK_SIZE blocks. */
893 if (unlikely(esector < BM_SECT_PER_BIT-1))
894 goto out;
895 if (unlikely(esector == (nr_sectors-1)))
896 ebnr = lbnr;
897 else
898 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
899 sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
900 } else {
901 /* We set it out of sync, or record resync failure.
902 * Should not round anything here. */
903 sbnr = BM_SECT_TO_BIT(sector);
904 ebnr = BM_SECT_TO_BIT(esector);
905 }
906
907 count = update_sync_bits(device, sbnr, ebnr, mode);
908out:
909 put_ldev(device);
910 return count;
911}
912
913static
914struct bm_extent *_bme_get(struct drbd_device *device, unsigned int enr)
915{
916 struct lc_element *e;
917 struct bm_extent *bm_ext;
918 int wakeup = 0;
919 unsigned long rs_flags;
920
921 spin_lock_irq(&device->al_lock);
922 if (device->resync_locked > device->resync->nr_elements/2) {
923 spin_unlock_irq(&device->al_lock);
924 return NULL;
925 }
926 e = lc_get(device->resync, enr);
927 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
928 if (bm_ext) {
929 if (bm_ext->lce.lc_number != enr) {
930 bm_ext->rs_left = drbd_bm_e_weight(device, enr);
931 bm_ext->rs_failed = 0;
932 lc_committed(device->resync);
933 wakeup = 1;
934 }
935 if (bm_ext->lce.refcnt == 1)
936 device->resync_locked++;
937 set_bit(BME_NO_WRITES, &bm_ext->flags);
938 }
939 rs_flags = device->resync->flags;
940 spin_unlock_irq(&device->al_lock);
941 if (wakeup)
942 wake_up(&device->al_wait);
943
944 if (!bm_ext) {
945 if (rs_flags & LC_STARVING)
946 drbd_warn(device, "Have to wait for element"
947 " (resync LRU too small?)\n");
948 BUG_ON(rs_flags & LC_LOCKED);
949 }
950
951 return bm_ext;
952}
953
954static int _is_in_al(struct drbd_device *device, unsigned int enr)
955{
956 int rv;
957
958 spin_lock_irq(&device->al_lock);
959 rv = lc_is_used(device->act_log, enr);
960 spin_unlock_irq(&device->al_lock);
961
962 return rv;
963}
964
965/**
966 * drbd_rs_begin_io() - Gets an extent in the resync LRU cache and sets it to BME_LOCKED
967 * @device: DRBD device.
968 * @sector: The sector number.
969 *
970 * This functions sleeps on al_wait. Returns 0 on success, -EINTR if interrupted.
971 */
972int drbd_rs_begin_io(struct drbd_device *device, sector_t sector)
973{
974 unsigned int enr = BM_SECT_TO_EXT(sector);
975 struct bm_extent *bm_ext;
976 int i, sig;
977 bool sa;
978
979retry:
980 sig = wait_event_interruptible(device->al_wait,
981 (bm_ext = _bme_get(device, enr)));
982 if (sig)
983 return -EINTR;
984
985 if (test_bit(BME_LOCKED, &bm_ext->flags))
986 return 0;
987
988 /* step aside only while we are above c-min-rate; unless disabled. */
989 sa = drbd_rs_c_min_rate_throttle(device);
990
991 for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
992 sig = wait_event_interruptible(device->al_wait,
993 !_is_in_al(device, enr * AL_EXT_PER_BM_SECT + i) ||
994 (sa && test_bit(BME_PRIORITY, &bm_ext->flags)));
995
996 if (sig || (sa && test_bit(BME_PRIORITY, &bm_ext->flags))) {
997 spin_lock_irq(&device->al_lock);
998 if (lc_put(device->resync, &bm_ext->lce) == 0) {
999 bm_ext->flags = 0; /* clears BME_NO_WRITES and eventually BME_PRIORITY */
1000 device->resync_locked--;
1001 wake_up(&device->al_wait);
1002 }
1003 spin_unlock_irq(&device->al_lock);
1004 if (sig)
1005 return -EINTR;
1006 if (schedule_timeout_interruptible(HZ/10))
1007 return -EINTR;
1008 goto retry;
1009 }
1010 }
1011 set_bit(BME_LOCKED, &bm_ext->flags);
1012 return 0;
1013}
1014
1015/**
1016 * drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep
1017 * @device: DRBD device.
1018 * @sector: The sector number.
1019 *
1020 * Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then
1021 * tries to set it to BME_LOCKED. Returns 0 upon success, and -EAGAIN
1022 * if there is still application IO going on in this area.
1023 */
1024int drbd_try_rs_begin_io(struct drbd_device *device, sector_t sector)
1025{
1026 unsigned int enr = BM_SECT_TO_EXT(sector);
1027 const unsigned int al_enr = enr*AL_EXT_PER_BM_SECT;
1028 struct lc_element *e;
1029 struct bm_extent *bm_ext;
1030 int i;
1031 bool throttle = drbd_rs_should_slow_down(device, sector, true);
1032
1033 /* If we need to throttle, a half-locked (only marked BME_NO_WRITES,
1034 * not yet BME_LOCKED) extent needs to be kicked out explicitly if we
1035 * need to throttle. There is at most one such half-locked extent,
1036 * which is remembered in resync_wenr. */
1037
1038 if (throttle && device->resync_wenr != enr)
1039 return -EAGAIN;
1040
1041 spin_lock_irq(&device->al_lock);
1042 if (device->resync_wenr != LC_FREE && device->resync_wenr != enr) {
1043 /* in case you have very heavy scattered io, it may
1044 * stall the syncer undefined if we give up the ref count
1045 * when we try again and requeue.
1046 *
1047 * if we don't give up the refcount, but the next time
1048 * we are scheduled this extent has been "synced" by new
1049 * application writes, we'd miss the lc_put on the
1050 * extent we keep the refcount on.
1051 * so we remembered which extent we had to try again, and
1052 * if the next requested one is something else, we do
1053 * the lc_put here...
1054 * we also have to wake_up
1055 */
1056 e = lc_find(device->resync, device->resync_wenr);
1057 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1058 if (bm_ext) {
1059 D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1060 D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1061 clear_bit(BME_NO_WRITES, &bm_ext->flags);
1062 device->resync_wenr = LC_FREE;
1063 if (lc_put(device->resync, &bm_ext->lce) == 0) {
1064 bm_ext->flags = 0;
1065 device->resync_locked--;
1066 }
1067 wake_up(&device->al_wait);
1068 } else {
1069 drbd_alert(device, "LOGIC BUG\n");
1070 }
1071 }
1072 /* TRY. */
1073 e = lc_try_get(device->resync, enr);
1074 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1075 if (bm_ext) {
1076 if (test_bit(BME_LOCKED, &bm_ext->flags))
1077 goto proceed;
1078 if (!test_and_set_bit(BME_NO_WRITES, &bm_ext->flags)) {
1079 device->resync_locked++;
1080 } else {
1081 /* we did set the BME_NO_WRITES,
1082 * but then could not set BME_LOCKED,
1083 * so we tried again.
1084 * drop the extra reference. */
1085 bm_ext->lce.refcnt--;
1086 D_ASSERT(device, bm_ext->lce.refcnt > 0);
1087 }
1088 goto check_al;
1089 } else {
1090 /* do we rather want to try later? */
1091 if (device->resync_locked > device->resync->nr_elements-3)
1092 goto try_again;
1093 /* Do or do not. There is no try. -- Yoda */
1094 e = lc_get(device->resync, enr);
1095 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1096 if (!bm_ext) {
1097 const unsigned long rs_flags = device->resync->flags;
1098 if (rs_flags & LC_STARVING)
1099 drbd_warn(device, "Have to wait for element"
1100 " (resync LRU too small?)\n");
1101 BUG_ON(rs_flags & LC_LOCKED);
1102 goto try_again;
1103 }
1104 if (bm_ext->lce.lc_number != enr) {
1105 bm_ext->rs_left = drbd_bm_e_weight(device, enr);
1106 bm_ext->rs_failed = 0;
1107 lc_committed(device->resync);
1108 wake_up(&device->al_wait);
1109 D_ASSERT(device, test_bit(BME_LOCKED, &bm_ext->flags) == 0);
1110 }
1111 set_bit(BME_NO_WRITES, &bm_ext->flags);
1112 D_ASSERT(device, bm_ext->lce.refcnt == 1);
1113 device->resync_locked++;
1114 goto check_al;
1115 }
1116check_al:
1117 for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
1118 if (lc_is_used(device->act_log, al_enr+i))
1119 goto try_again;
1120 }
1121 set_bit(BME_LOCKED, &bm_ext->flags);
1122proceed:
1123 device->resync_wenr = LC_FREE;
1124 spin_unlock_irq(&device->al_lock);
1125 return 0;
1126
1127try_again:
1128 if (bm_ext) {
1129 if (throttle) {
1130 D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1131 D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1132 clear_bit(BME_NO_WRITES, &bm_ext->flags);
1133 device->resync_wenr = LC_FREE;
1134 if (lc_put(device->resync, &bm_ext->lce) == 0) {
1135 bm_ext->flags = 0;
1136 device->resync_locked--;
1137 }
1138 wake_up(&device->al_wait);
1139 } else
1140 device->resync_wenr = enr;
1141 }
1142 spin_unlock_irq(&device->al_lock);
1143 return -EAGAIN;
1144}
1145
1146void drbd_rs_complete_io(struct drbd_device *device, sector_t sector)
1147{
1148 unsigned int enr = BM_SECT_TO_EXT(sector);
1149 struct lc_element *e;
1150 struct bm_extent *bm_ext;
1151 unsigned long flags;
1152
1153 spin_lock_irqsave(&device->al_lock, flags);
1154 e = lc_find(device->resync, enr);
1155 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1156 if (!bm_ext) {
1157 spin_unlock_irqrestore(&device->al_lock, flags);
1158 if (__ratelimit(&drbd_ratelimit_state))
1159 drbd_err(device, "drbd_rs_complete_io() called, but extent not found\n");
1160 return;
1161 }
1162
1163 if (bm_ext->lce.refcnt == 0) {
1164 spin_unlock_irqrestore(&device->al_lock, flags);
1165 drbd_err(device, "drbd_rs_complete_io(,%llu [=%u]) called, "
1166 "but refcnt is 0!?\n",
1167 (unsigned long long)sector, enr);
1168 return;
1169 }
1170
1171 if (lc_put(device->resync, &bm_ext->lce) == 0) {
1172 bm_ext->flags = 0; /* clear BME_LOCKED, BME_NO_WRITES and BME_PRIORITY */
1173 device->resync_locked--;
1174 wake_up(&device->al_wait);
1175 }
1176
1177 spin_unlock_irqrestore(&device->al_lock, flags);
1178}
1179
1180/**
1181 * drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED)
1182 * @device: DRBD device.
1183 */
1184void drbd_rs_cancel_all(struct drbd_device *device)
1185{
1186 spin_lock_irq(&device->al_lock);
1187
1188 if (get_ldev_if_state(device, D_FAILED)) { /* Makes sure ->resync is there. */
1189 lc_reset(device->resync);
1190 put_ldev(device);
1191 }
1192 device->resync_locked = 0;
1193 device->resync_wenr = LC_FREE;
1194 spin_unlock_irq(&device->al_lock);
1195 wake_up(&device->al_wait);
1196}
1197
1198/**
1199 * drbd_rs_del_all() - Gracefully remove all extents from the resync LRU
1200 * @device: DRBD device.
1201 *
1202 * Returns 0 upon success, -EAGAIN if at least one reference count was
1203 * not zero.
1204 */
1205int drbd_rs_del_all(struct drbd_device *device)
1206{
1207 struct lc_element *e;
1208 struct bm_extent *bm_ext;
1209 int i;
1210
1211 spin_lock_irq(&device->al_lock);
1212
1213 if (get_ldev_if_state(device, D_FAILED)) {
1214 /* ok, ->resync is there. */
1215 for (i = 0; i < device->resync->nr_elements; i++) {
1216 e = lc_element_by_index(device->resync, i);
1217 bm_ext = lc_entry(e, struct bm_extent, lce);
1218 if (bm_ext->lce.lc_number == LC_FREE)
1219 continue;
1220 if (bm_ext->lce.lc_number == device->resync_wenr) {
1221 drbd_info(device, "dropping %u in drbd_rs_del_all, apparently"
1222 " got 'synced' by application io\n",
1223 device->resync_wenr);
1224 D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1225 D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1226 clear_bit(BME_NO_WRITES, &bm_ext->flags);
1227 device->resync_wenr = LC_FREE;
1228 lc_put(device->resync, &bm_ext->lce);
1229 }
1230 if (bm_ext->lce.refcnt != 0) {
1231 drbd_info(device, "Retrying drbd_rs_del_all() later. "
1232 "refcnt=%d\n", bm_ext->lce.refcnt);
1233 put_ldev(device);
1234 spin_unlock_irq(&device->al_lock);
1235 return -EAGAIN;
1236 }
1237 D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1238 D_ASSERT(device, !test_bit(BME_NO_WRITES, &bm_ext->flags));
1239 lc_del(device->resync, &bm_ext->lce);
1240 }
1241 D_ASSERT(device, device->resync->used == 0);
1242 put_ldev(device);
1243 }
1244 spin_unlock_irq(&device->al_lock);
1245 wake_up(&device->al_wait);
1246
1247 return 0;
1248}