1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 drbd_bitmap.c
4
5 This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
6
7 Copyright (C) 2004-2008, LINBIT Information Technologies GmbH.
8 Copyright (C) 2004-2008, Philipp Reisner <philipp.reisner@linbit.com>.
9 Copyright (C) 2004-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
10
11 */
12
13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15#include <linux/bitmap.h>
16#include <linux/vmalloc.h>
17#include <linux/string.h>
18#include <linux/drbd.h>
19#include <linux/slab.h>
20#include <linux/highmem.h>
21
22#include "drbd_int.h"
23
24
25/* OPAQUE outside this file!
26 * interface defined in drbd_int.h
27
28 * convention:
29 * function name drbd_bm_... => used elsewhere, "public".
30 * function name bm_... => internal to implementation, "private".
31 */
32
33
34/*
35 * LIMITATIONS:
36 * We want to support >= peta byte of backend storage, while for now still using
37 * a granularity of one bit per 4KiB of storage.
38 * 1 << 50 bytes backend storage (1 PiB)
39 * 1 << (50 - 12) bits needed
40 * 38 --> we need u64 to index and count bits
41 * 1 << (38 - 3) bitmap bytes needed
42 * 35 --> we still need u64 to index and count bytes
43 * (that's 32 GiB of bitmap for 1 PiB storage)
44 * 1 << (35 - 2) 32bit longs needed
45 * 33 --> we'd even need u64 to index and count 32bit long words.
46 * 1 << (35 - 3) 64bit longs needed
47 * 32 --> we could get away with a 32bit unsigned int to index and count
48 * 64bit long words, but I rather stay with unsigned long for now.
49 * We probably should neither count nor point to bytes or long words
50 * directly, but either by bitnumber, or by page index and offset.
51 * 1 << (35 - 12)
52 * 22 --> we need that much 4KiB pages of bitmap.
53 * 1 << (22 + 3) --> on a 64bit arch,
54 * we need 32 MiB to store the array of page pointers.
55 *
56 * Because I'm lazy, and because the resulting patch was too large, too ugly
57 * and still incomplete, on 32bit we still "only" support 16 TiB (minus some),
58 * (1 << 32) bits * 4k storage.
59 *
60
61 * bitmap storage and IO:
62 * Bitmap is stored little endian on disk, and is kept little endian in
63 * core memory. Currently we still hold the full bitmap in core as long
64 * as we are "attached" to a local disk, which at 32 GiB for 1PiB storage
65 * seems excessive.
66 *
67 * We plan to reduce the amount of in-core bitmap pages by paging them in
68 * and out against their on-disk location as necessary, but need to make
69 * sure we don't cause too much meta data IO, and must not deadlock in
70 * tight memory situations. This needs some more work.
71 */
72
73/*
74 * NOTE
75 * Access to the *bm_pages is protected by bm_lock.
76 * It is safe to read the other members within the lock.
77 *
78 * drbd_bm_set_bits is called from bio_endio callbacks,
79 * We may be called with irq already disabled,
80 * so we need spin_lock_irqsave().
81 * And we need the kmap_atomic.
82 */
83struct drbd_bitmap {
84 struct page **bm_pages;
85 spinlock_t bm_lock;
86
87 /* exclusively to be used by __al_write_transaction(),
88 * drbd_bm_mark_for_writeout() and
89 * and drbd_bm_write_hinted() -> bm_rw() called from there.
90 */
91 unsigned int n_bitmap_hints;
92 unsigned int al_bitmap_hints[AL_UPDATES_PER_TRANSACTION];
93
94 /* see LIMITATIONS: above */
95
96 unsigned long bm_set; /* nr of set bits; THINK maybe atomic_t? */
97 unsigned long bm_bits;
98 size_t bm_words;
99 size_t bm_number_of_pages;
100 sector_t bm_dev_capacity;
101 struct mutex bm_change; /* serializes resize operations */
102
103 wait_queue_head_t bm_io_wait; /* used to serialize IO of single pages */
104
105 enum bm_flag bm_flags;
106
107 /* debugging aid, in case we are still racy somewhere */
108 char *bm_why;
109 struct task_struct *bm_task;
110};
111
112#define bm_print_lock_info(m) __bm_print_lock_info(m, __func__)
113static void __bm_print_lock_info(struct drbd_device *device, const char *func)
114{
115 struct drbd_bitmap *b = device->bitmap;
116 if (!drbd_ratelimit())
117 return;
118 drbd_err(device, "FIXME %s[%d] in %s, bitmap locked for '%s' by %s[%d]\n",
119 current->comm, task_pid_nr(current),
120 func, b->bm_why ?: "?",
121 b->bm_task->comm, task_pid_nr(b->bm_task));
122}
123
124void drbd_bm_lock(struct drbd_device *device, char *why, enum bm_flag flags)
125{
126 struct drbd_bitmap *b = device->bitmap;
127 int trylock_failed;
128
129 if (!b) {
130 drbd_err(device, "FIXME no bitmap in drbd_bm_lock!?\n");
131 return;
132 }
133
134 trylock_failed = !mutex_trylock(&b->bm_change);
135
136 if (trylock_failed) {
137 drbd_warn(device, "%s[%d] going to '%s' but bitmap already locked for '%s' by %s[%d]\n",
138 current->comm, task_pid_nr(current),
139 why, b->bm_why ?: "?",
140 b->bm_task->comm, task_pid_nr(b->bm_task));
141 mutex_lock(&b->bm_change);
142 }
143 if (BM_LOCKED_MASK & b->bm_flags)
144 drbd_err(device, "FIXME bitmap already locked in bm_lock\n");
145 b->bm_flags |= flags & BM_LOCKED_MASK;
146
147 b->bm_why = why;
148 b->bm_task = current;
149}
150
151void drbd_bm_unlock(struct drbd_device *device)
152{
153 struct drbd_bitmap *b = device->bitmap;
154 if (!b) {
155 drbd_err(device, "FIXME no bitmap in drbd_bm_unlock!?\n");
156 return;
157 }
158
159 if (!(BM_LOCKED_MASK & device->bitmap->bm_flags))
160 drbd_err(device, "FIXME bitmap not locked in bm_unlock\n");
161
162 b->bm_flags &= ~BM_LOCKED_MASK;
163 b->bm_why = NULL;
164 b->bm_task = NULL;
165 mutex_unlock(lock: &b->bm_change);
166}
167
168/* we store some "meta" info about our pages in page->private */
169/* at a granularity of 4k storage per bitmap bit:
170 * one peta byte storage: 1<<50 byte, 1<<38 * 4k storage blocks
171 * 1<<38 bits,
172 * 1<<23 4k bitmap pages.
173 * Use 24 bits as page index, covers 2 peta byte storage
174 * at a granularity of 4k per bit.
175 * Used to report the failed page idx on io error from the endio handlers.
176 */
177#define BM_PAGE_IDX_MASK ((1UL<<24)-1)
178/* this page is currently read in, or written back */
179#define BM_PAGE_IO_LOCK 31
180/* if there has been an IO error for this page */
181#define BM_PAGE_IO_ERROR 30
182/* this is to be able to intelligently skip disk IO,
183 * set if bits have been set since last IO. */
184#define BM_PAGE_NEED_WRITEOUT 29
185/* to mark for lazy writeout once syncer cleared all clearable bits,
186 * we if bits have been cleared since last IO. */
187#define BM_PAGE_LAZY_WRITEOUT 28
188/* pages marked with this "HINT" will be considered for writeout
189 * on activity log transactions */
190#define BM_PAGE_HINT_WRITEOUT 27
191
192/* store_page_idx uses non-atomic assignment. It is only used directly after
193 * allocating the page. All other bm_set_page_* and bm_clear_page_* need to
194 * use atomic bit manipulation, as set_out_of_sync (and therefore bitmap
195 * changes) may happen from various contexts, and wait_on_bit/wake_up_bit
196 * requires it all to be atomic as well. */
197static void bm_store_page_idx(struct page *page, unsigned long idx)
198{
199 BUG_ON(0 != (idx & ~BM_PAGE_IDX_MASK));
200 set_page_private(page, private: idx);
201}
202
203static unsigned long bm_page_to_idx(struct page *page)
204{
205 return page_private(page) & BM_PAGE_IDX_MASK;
206}
207
208/* As is very unlikely that the same page is under IO from more than one
209 * context, we can get away with a bit per page and one wait queue per bitmap.
210 */
211static void bm_page_lock_io(struct drbd_device *device, int page_nr)
212{
213 struct drbd_bitmap *b = device->bitmap;
214 void *addr = &page_private(b->bm_pages[page_nr]);
215 wait_event(b->bm_io_wait, !test_and_set_bit(BM_PAGE_IO_LOCK, addr));
216}
217
218static void bm_page_unlock_io(struct drbd_device *device, int page_nr)
219{
220 struct drbd_bitmap *b = device->bitmap;
221 void *addr = &page_private(b->bm_pages[page_nr]);
222 clear_bit_unlock(BM_PAGE_IO_LOCK, addr);
223 wake_up(&device->bitmap->bm_io_wait);
224}
225
226/* set _before_ submit_io, so it may be reset due to being changed
227 * while this page is in flight... will get submitted later again */
228static void bm_set_page_unchanged(struct page *page)
229{
230 /* use cmpxchg? */
231 clear_bit(BM_PAGE_NEED_WRITEOUT, addr: &page_private(page));
232 clear_bit(BM_PAGE_LAZY_WRITEOUT, addr: &page_private(page));
233}
234
235static void bm_set_page_need_writeout(struct page *page)
236{
237 set_bit(BM_PAGE_NEED_WRITEOUT, addr: &page_private(page));
238}
239
240void drbd_bm_reset_al_hints(struct drbd_device *device)
241{
242 device->bitmap->n_bitmap_hints = 0;
243}
244
245/**
246 * drbd_bm_mark_for_writeout() - mark a page with a "hint" to be considered for writeout
247 * @device: DRBD device.
248 * @page_nr: the bitmap page to mark with the "hint" flag
249 *
250 * From within an activity log transaction, we mark a few pages with these
251 * hints, then call drbd_bm_write_hinted(), which will only write out changed
252 * pages which are flagged with this mark.
253 */
254void drbd_bm_mark_for_writeout(struct drbd_device *device, int page_nr)
255{
256 struct drbd_bitmap *b = device->bitmap;
257 struct page *page;
258 if (page_nr >= device->bitmap->bm_number_of_pages) {
259 drbd_warn(device, "BAD: page_nr: %u, number_of_pages: %u\n",
260 page_nr, (int)device->bitmap->bm_number_of_pages);
261 return;
262 }
263 page = device->bitmap->bm_pages[page_nr];
264 BUG_ON(b->n_bitmap_hints >= ARRAY_SIZE(b->al_bitmap_hints));
265 if (!test_and_set_bit(BM_PAGE_HINT_WRITEOUT, addr: &page_private(page)))
266 b->al_bitmap_hints[b->n_bitmap_hints++] = page_nr;
267}
268
269static int bm_test_page_unchanged(struct page *page)
270{
271 volatile const unsigned long *addr = &page_private(page);
272 return (*addr & ((1UL<<BM_PAGE_NEED_WRITEOUT)|(1UL<<BM_PAGE_LAZY_WRITEOUT))) == 0;
273}
274
275static void bm_set_page_io_err(struct page *page)
276{
277 set_bit(BM_PAGE_IO_ERROR, addr: &page_private(page));
278}
279
280static void bm_clear_page_io_err(struct page *page)
281{
282 clear_bit(BM_PAGE_IO_ERROR, addr: &page_private(page));
283}
284
285static void bm_set_page_lazy_writeout(struct page *page)
286{
287 set_bit(BM_PAGE_LAZY_WRITEOUT, addr: &page_private(page));
288}
289
290static int bm_test_page_lazy_writeout(struct page *page)
291{
292 return test_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page));
293}
294
295/* on a 32bit box, this would allow for exactly (2<<38) bits. */
296static unsigned int bm_word_to_page_idx(struct drbd_bitmap *b, unsigned long long_nr)
297{
298 /* page_nr = (word*sizeof(long)) >> PAGE_SHIFT; */
299 unsigned int page_nr = long_nr >> (PAGE_SHIFT - LN2_BPL + 3);
300 BUG_ON(page_nr >= b->bm_number_of_pages);
301 return page_nr;
302}
303
304static unsigned int bm_bit_to_page_idx(struct drbd_bitmap *b, u64 bitnr)
305{
306 /* page_nr = (bitnr/8) >> PAGE_SHIFT; */
307 unsigned int page_nr = bitnr >> (PAGE_SHIFT + 3);
308 BUG_ON(page_nr >= b->bm_number_of_pages);
309 return page_nr;
310}
311
312static unsigned long *__bm_map_pidx(struct drbd_bitmap *b, unsigned int idx)
313{
314 struct page *page = b->bm_pages[idx];
315 return (unsigned long *) kmap_atomic(page);
316}
317
318static unsigned long *bm_map_pidx(struct drbd_bitmap *b, unsigned int idx)
319{
320 return __bm_map_pidx(b, idx);
321}
322
323static void __bm_unmap(unsigned long *p_addr)
324{
325 kunmap_atomic(p_addr);
326};
327
328static void bm_unmap(unsigned long *p_addr)
329{
330 return __bm_unmap(p_addr);
331}
332
333/* long word offset of _bitmap_ sector */
334#define S2W(s) ((s)<<(BM_EXT_SHIFT-BM_BLOCK_SHIFT-LN2_BPL))
335/* word offset from start of bitmap to word number _in_page_
336 * modulo longs per page
337#define MLPP(X) ((X) % (PAGE_SIZE/sizeof(long))
338 hm, well, Philipp thinks gcc might not optimize the % into & (... - 1)
339 so do it explicitly:
340 */
341#define MLPP(X) ((X) & ((PAGE_SIZE/sizeof(long))-1))
342
343/* Long words per page */
344#define LWPP (PAGE_SIZE/sizeof(long))
345
346/*
347 * actually most functions herein should take a struct drbd_bitmap*, not a
348 * struct drbd_device*, but for the debug macros I like to have the device around
349 * to be able to report device specific.
350 */
351
352
353static void bm_free_pages(struct page **pages, unsigned long number)
354{
355 unsigned long i;
356 if (!pages)
357 return;
358
359 for (i = 0; i < number; i++) {
360 if (!pages[i]) {
361 pr_alert("bm_free_pages tried to free a NULL pointer; i=%lu n=%lu\n",
362 i, number);
363 continue;
364 }
365 __free_page(pages[i]);
366 pages[i] = NULL;
367 }
368}
369
370static inline void bm_vk_free(void *ptr)
371{
372 kvfree(addr: ptr);
373}
374
375/*
376 * "have" and "want" are NUMBER OF PAGES.
377 */
378static struct page **bm_realloc_pages(struct drbd_bitmap *b, unsigned long want)
379{
380 struct page **old_pages = b->bm_pages;
381 struct page **new_pages, *page;
382 unsigned int i, bytes;
383 unsigned long have = b->bm_number_of_pages;
384
385 BUG_ON(have == 0 && old_pages != NULL);
386 BUG_ON(have != 0 && old_pages == NULL);
387
388 if (have == want)
389 return old_pages;
390
391 /* Trying kmalloc first, falling back to vmalloc.
392 * GFP_NOIO, as this is called while drbd IO is "suspended",
393 * and during resize or attach on diskless Primary,
394 * we must not block on IO to ourselves.
395 * Context is receiver thread or dmsetup. */
396 bytes = sizeof(struct page *)*want;
397 new_pages = kzalloc(bytes, GFP_NOIO | __GFP_NOWARN);
398 if (!new_pages) {
399 new_pages = __vmalloc(bytes, GFP_NOIO | __GFP_ZERO);
400 if (!new_pages)
401 return NULL;
402 }
403
404 if (want >= have) {
405 for (i = 0; i < have; i++)
406 new_pages[i] = old_pages[i];
407 for (; i < want; i++) {
408 page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
409 if (!page) {
410 bm_free_pages(pages: new_pages + have, number: i - have);
411 bm_vk_free(ptr: new_pages);
412 return NULL;
413 }
414 /* we want to know which page it is
415 * from the endio handlers */
416 bm_store_page_idx(page, idx: i);
417 new_pages[i] = page;
418 }
419 } else {
420 for (i = 0; i < want; i++)
421 new_pages[i] = old_pages[i];
422 /* NOT HERE, we are outside the spinlock!
423 bm_free_pages(old_pages + want, have - want);
424 */
425 }
426
427 return new_pages;
428}
429
430/*
431 * allocates the drbd_bitmap and stores it in device->bitmap.
432 */
433int drbd_bm_init(struct drbd_device *device)
434{
435 struct drbd_bitmap *b = device->bitmap;
436 WARN_ON(b != NULL);
437 b = kzalloc(sizeof(struct drbd_bitmap), GFP_KERNEL);
438 if (!b)
439 return -ENOMEM;
440 spin_lock_init(&b->bm_lock);
441 mutex_init(&b->bm_change);
442 init_waitqueue_head(&b->bm_io_wait);
443
444 device->bitmap = b;
445
446 return 0;
447}
448
449sector_t drbd_bm_capacity(struct drbd_device *device)
450{
451 if (!expect(device, device->bitmap))
452 return 0;
453 return device->bitmap->bm_dev_capacity;
454}
455
456/* called on driver unload. TODO: call when a device is destroyed.
457 */
458void drbd_bm_cleanup(struct drbd_device *device)
459{
460 if (!expect(device, device->bitmap))
461 return;
462 bm_free_pages(pages: device->bitmap->bm_pages, number: device->bitmap->bm_number_of_pages);
463 bm_vk_free(ptr: device->bitmap->bm_pages);
464 kfree(objp: device->bitmap);
465 device->bitmap = NULL;
466}
467
468/*
469 * since (b->bm_bits % BITS_PER_LONG) != 0,
470 * this masks out the remaining bits.
471 * Returns the number of bits cleared.
472 */
473#ifndef BITS_PER_PAGE
474#define BITS_PER_PAGE (1UL << (PAGE_SHIFT + 3))
475#define BITS_PER_PAGE_MASK (BITS_PER_PAGE - 1)
476#else
477# if BITS_PER_PAGE != (1UL << (PAGE_SHIFT + 3))
478# error "ambiguous BITS_PER_PAGE"
479# endif
480#endif
481#define BITS_PER_LONG_MASK (BITS_PER_LONG - 1)
482static int bm_clear_surplus(struct drbd_bitmap *b)
483{
484 unsigned long mask;
485 unsigned long *p_addr, *bm;
486 int tmp;
487 int cleared = 0;
488
489 /* number of bits modulo bits per page */
490 tmp = (b->bm_bits & BITS_PER_PAGE_MASK);
491 /* mask the used bits of the word containing the last bit */
492 mask = (1UL << (tmp & BITS_PER_LONG_MASK)) -1;
493 /* bitmap is always stored little endian,
494 * on disk and in core memory alike */
495 mask = cpu_to_lel(mask);
496
497 p_addr = bm_map_pidx(b, idx: b->bm_number_of_pages - 1);
498 bm = p_addr + (tmp/BITS_PER_LONG);
499 if (mask) {
500 /* If mask != 0, we are not exactly aligned, so bm now points
501 * to the long containing the last bit.
502 * If mask == 0, bm already points to the word immediately
503 * after the last (long word aligned) bit. */
504 cleared = hweight_long(w: *bm & ~mask);
505 *bm &= mask;
506 bm++;
507 }
508
509 if (BITS_PER_LONG == 32 && ((bm - p_addr) & 1) == 1) {
510 /* on a 32bit arch, we may need to zero out
511 * a padding long to align with a 64bit remote */
512 cleared += hweight_long(w: *bm);
513 *bm = 0;
514 }
515 bm_unmap(p_addr);
516 return cleared;
517}
518
519static void bm_set_surplus(struct drbd_bitmap *b)
520{
521 unsigned long mask;
522 unsigned long *p_addr, *bm;
523 int tmp;
524
525 /* number of bits modulo bits per page */
526 tmp = (b->bm_bits & BITS_PER_PAGE_MASK);
527 /* mask the used bits of the word containing the last bit */
528 mask = (1UL << (tmp & BITS_PER_LONG_MASK)) -1;
529 /* bitmap is always stored little endian,
530 * on disk and in core memory alike */
531 mask = cpu_to_lel(mask);
532
533 p_addr = bm_map_pidx(b, idx: b->bm_number_of_pages - 1);
534 bm = p_addr + (tmp/BITS_PER_LONG);
535 if (mask) {
536 /* If mask != 0, we are not exactly aligned, so bm now points
537 * to the long containing the last bit.
538 * If mask == 0, bm already points to the word immediately
539 * after the last (long word aligned) bit. */
540 *bm |= ~mask;
541 bm++;
542 }
543
544 if (BITS_PER_LONG == 32 && ((bm - p_addr) & 1) == 1) {
545 /* on a 32bit arch, we may need to zero out
546 * a padding long to align with a 64bit remote */
547 *bm = ~0UL;
548 }
549 bm_unmap(p_addr);
550}
551
552/* you better not modify the bitmap while this is running,
553 * or its results will be stale */
554static unsigned long bm_count_bits(struct drbd_bitmap *b)
555{
556 unsigned long *p_addr;
557 unsigned long bits = 0;
558 unsigned long mask = (1UL << (b->bm_bits & BITS_PER_LONG_MASK)) -1;
559 int idx, last_word;
560
561 /* all but last page */
562 for (idx = 0; idx < b->bm_number_of_pages - 1; idx++) {
563 p_addr = __bm_map_pidx(b, idx);
564 bits += bitmap_weight(src: p_addr, BITS_PER_PAGE);
565 __bm_unmap(p_addr);
566 cond_resched();
567 }
568 /* last (or only) page */
569 last_word = ((b->bm_bits - 1) & BITS_PER_PAGE_MASK) >> LN2_BPL;
570 p_addr = __bm_map_pidx(b, idx);
571 bits += bitmap_weight(src: p_addr, nbits: last_word * BITS_PER_LONG);
572 p_addr[last_word] &= cpu_to_lel(mask);
573 bits += hweight_long(w: p_addr[last_word]);
574 /* 32bit arch, may have an unused padding long */
575 if (BITS_PER_LONG == 32 && (last_word & 1) == 0)
576 p_addr[last_word+1] = 0;
577 __bm_unmap(p_addr);
578 return bits;
579}
580
581/* offset and len in long words.*/
582static void bm_memset(struct drbd_bitmap *b, size_t offset, int c, size_t len)
583{
584 unsigned long *p_addr, *bm;
585 unsigned int idx;
586 size_t do_now, end;
587
588 end = offset + len;
589
590 if (end > b->bm_words) {
591 pr_alert("bm_memset end > bm_words\n");
592 return;
593 }
594
595 while (offset < end) {
596 do_now = min_t(size_t, ALIGN(offset + 1, LWPP), end) - offset;
597 idx = bm_word_to_page_idx(b, long_nr: offset);
598 p_addr = bm_map_pidx(b, idx);
599 bm = p_addr + MLPP(offset);
600 if (bm+do_now > p_addr + LWPP) {
601 pr_alert("BUG BUG BUG! p_addr:%p bm:%p do_now:%d\n",
602 p_addr, bm, (int)do_now);
603 } else
604 memset(bm, c, do_now * sizeof(long));
605 bm_unmap(p_addr);
606 bm_set_page_need_writeout(page: b->bm_pages[idx]);
607 offset += do_now;
608 }
609}
610
611/* For the layout, see comment above drbd_md_set_sector_offsets(). */
612static u64 drbd_md_on_disk_bits(struct drbd_backing_dev *ldev)
613{
614 u64 bitmap_sectors;
615 if (ldev->md.al_offset == 8)
616 bitmap_sectors = ldev->md.md_size_sect - ldev->md.bm_offset;
617 else
618 bitmap_sectors = ldev->md.al_offset - ldev->md.bm_offset;
619 return bitmap_sectors << (9 + 3);
620}
621
622/*
623 * make sure the bitmap has enough room for the attached storage,
624 * if necessary, resize.
625 * called whenever we may have changed the device size.
626 * returns -ENOMEM if we could not allocate enough memory, 0 on success.
627 * In case this is actually a resize, we copy the old bitmap into the new one.
628 * Otherwise, the bitmap is initialized to all bits set.
629 */
630int drbd_bm_resize(struct drbd_device *device, sector_t capacity, int set_new_bits)
631{
632 struct drbd_bitmap *b = device->bitmap;
633 unsigned long bits, words, owords, obits;
634 unsigned long want, have, onpages; /* number of pages */
635 struct page **npages, **opages = NULL;
636 int err = 0;
637 bool growing;
638
639 if (!expect(device, b))
640 return -ENOMEM;
641
642 drbd_bm_lock(device, why: "resize", flags: BM_LOCKED_MASK);
643
644 drbd_info(device, "drbd_bm_resize called with capacity == %llu\n",
645 (unsigned long long)capacity);
646
647 if (capacity == b->bm_dev_capacity)
648 goto out;
649
650 if (capacity == 0) {
651 spin_lock_irq(lock: &b->bm_lock);
652 opages = b->bm_pages;
653 onpages = b->bm_number_of_pages;
654 owords = b->bm_words;
655 b->bm_pages = NULL;
656 b->bm_number_of_pages =
657 b->bm_set =
658 b->bm_bits =
659 b->bm_words =
660 b->bm_dev_capacity = 0;
661 spin_unlock_irq(lock: &b->bm_lock);
662 bm_free_pages(pages: opages, number: onpages);
663 bm_vk_free(ptr: opages);
664 goto out;
665 }
666 bits = BM_SECT_TO_BIT(ALIGN(capacity, BM_SECT_PER_BIT));
667
668 /* if we would use
669 words = ALIGN(bits,BITS_PER_LONG) >> LN2_BPL;
670 a 32bit host could present the wrong number of words
671 to a 64bit host.
672 */
673 words = ALIGN(bits, 64) >> LN2_BPL;
674
675 if (get_ldev(device)) {
676 u64 bits_on_disk = drbd_md_on_disk_bits(ldev: device->ldev);
677 put_ldev(device);
678 if (bits > bits_on_disk) {
679 drbd_info(device, "bits = %lu\n", bits);
680 drbd_info(device, "bits_on_disk = %llu\n", bits_on_disk);
681 err = -ENOSPC;
682 goto out;
683 }
684 }
685
686 want = PFN_UP(words*sizeof(long));
687 have = b->bm_number_of_pages;
688 if (want == have) {
689 D_ASSERT(device, b->bm_pages != NULL);
690 npages = b->bm_pages;
691 } else {
692 if (drbd_insert_fault(device, type: DRBD_FAULT_BM_ALLOC))
693 npages = NULL;
694 else
695 npages = bm_realloc_pages(b, want);
696 }
697
698 if (!npages) {
699 err = -ENOMEM;
700 goto out;
701 }
702
703 spin_lock_irq(lock: &b->bm_lock);
704 opages = b->bm_pages;
705 owords = b->bm_words;
706 obits = b->bm_bits;
707
708 growing = bits > obits;
709 if (opages && growing && set_new_bits)
710 bm_set_surplus(b);
711
712 b->bm_pages = npages;
713 b->bm_number_of_pages = want;
714 b->bm_bits = bits;
715 b->bm_words = words;
716 b->bm_dev_capacity = capacity;
717
718 if (growing) {
719 if (set_new_bits) {
720 bm_memset(b, offset: owords, c: 0xff, len: words-owords);
721 b->bm_set += bits - obits;
722 } else
723 bm_memset(b, offset: owords, c: 0x00, len: words-owords);
724
725 }
726
727 if (want < have) {
728 /* implicit: (opages != NULL) && (opages != npages) */
729 bm_free_pages(pages: opages + want, number: have - want);
730 }
731
732 (void)bm_clear_surplus(b);
733
734 spin_unlock_irq(lock: &b->bm_lock);
735 if (opages != npages)
736 bm_vk_free(ptr: opages);
737 if (!growing)
738 b->bm_set = bm_count_bits(b);
739 drbd_info(device, "resync bitmap: bits=%lu words=%lu pages=%lu\n", bits, words, want);
740
741 out:
742 drbd_bm_unlock(device);
743 return err;
744}
745
746/* inherently racy:
747 * if not protected by other means, return value may be out of date when
748 * leaving this function...
749 * we still need to lock it, since it is important that this returns
750 * bm_set == 0 precisely.
751 *
752 * maybe bm_set should be atomic_t ?
753 */
754unsigned long _drbd_bm_total_weight(struct drbd_device *device)
755{
756 struct drbd_bitmap *b = device->bitmap;
757 unsigned long s;
758 unsigned long flags;
759
760 if (!expect(device, b))
761 return 0;
762 if (!expect(device, b->bm_pages))
763 return 0;
764
765 spin_lock_irqsave(&b->bm_lock, flags);
766 s = b->bm_set;
767 spin_unlock_irqrestore(lock: &b->bm_lock, flags);
768
769 return s;
770}
771
772unsigned long drbd_bm_total_weight(struct drbd_device *device)
773{
774 unsigned long s;
775 /* if I don't have a disk, I don't know about out-of-sync status */
776 if (!get_ldev_if_state(device, D_NEGOTIATING))
777 return 0;
778 s = _drbd_bm_total_weight(device);
779 put_ldev(device);
780 return s;
781}
782
783size_t drbd_bm_words(struct drbd_device *device)
784{
785 struct drbd_bitmap *b = device->bitmap;
786 if (!expect(device, b))
787 return 0;
788 if (!expect(device, b->bm_pages))
789 return 0;
790
791 return b->bm_words;
792}
793
794unsigned long drbd_bm_bits(struct drbd_device *device)
795{
796 struct drbd_bitmap *b = device->bitmap;
797 if (!expect(device, b))
798 return 0;
799
800 return b->bm_bits;
801}
802
803/* merge number words from buffer into the bitmap starting at offset.
804 * buffer[i] is expected to be little endian unsigned long.
805 * bitmap must be locked by drbd_bm_lock.
806 * currently only used from receive_bitmap.
807 */
808void drbd_bm_merge_lel(struct drbd_device *device, size_t offset, size_t number,
809 unsigned long *buffer)
810{
811 struct drbd_bitmap *b = device->bitmap;
812 unsigned long *p_addr, *bm;
813 unsigned long word, bits;
814 unsigned int idx;
815 size_t end, do_now;
816
817 end = offset + number;
818
819 if (!expect(device, b))
820 return;
821 if (!expect(device, b->bm_pages))
822 return;
823 if (number == 0)
824 return;
825 WARN_ON(offset >= b->bm_words);
826 WARN_ON(end > b->bm_words);
827
828 spin_lock_irq(lock: &b->bm_lock);
829 while (offset < end) {
830 do_now = min_t(size_t, ALIGN(offset+1, LWPP), end) - offset;
831 idx = bm_word_to_page_idx(b, long_nr: offset);
832 p_addr = bm_map_pidx(b, idx);
833 bm = p_addr + MLPP(offset);
834 offset += do_now;
835 while (do_now--) {
836 bits = hweight_long(w: *bm);
837 word = *bm | *buffer++;
838 *bm++ = word;
839 b->bm_set += hweight_long(w: word) - bits;
840 }
841 bm_unmap(p_addr);
842 bm_set_page_need_writeout(page: b->bm_pages[idx]);
843 }
844 /* with 32bit <-> 64bit cross-platform connect
845 * this is only correct for current usage,
846 * where we _know_ that we are 64 bit aligned,
847 * and know that this function is used in this way, too...
848 */
849 if (end == b->bm_words)
850 b->bm_set -= bm_clear_surplus(b);
851 spin_unlock_irq(lock: &b->bm_lock);
852}
853
854/* copy number words from the bitmap starting at offset into the buffer.
855 * buffer[i] will be little endian unsigned long.
856 */
857void drbd_bm_get_lel(struct drbd_device *device, size_t offset, size_t number,
858 unsigned long *buffer)
859{
860 struct drbd_bitmap *b = device->bitmap;
861 unsigned long *p_addr, *bm;
862 size_t end, do_now;
863
864 end = offset + number;
865
866 if (!expect(device, b))
867 return;
868 if (!expect(device, b->bm_pages))
869 return;
870
871 spin_lock_irq(lock: &b->bm_lock);
872 if ((offset >= b->bm_words) ||
873 (end > b->bm_words) ||
874 (number <= 0))
875 drbd_err(device, "offset=%lu number=%lu bm_words=%lu\n",
876 (unsigned long) offset,
877 (unsigned long) number,
878 (unsigned long) b->bm_words);
879 else {
880 while (offset < end) {
881 do_now = min_t(size_t, ALIGN(offset+1, LWPP), end) - offset;
882 p_addr = bm_map_pidx(b, idx: bm_word_to_page_idx(b, long_nr: offset));
883 bm = p_addr + MLPP(offset);
884 offset += do_now;
885 while (do_now--)
886 *buffer++ = *bm++;
887 bm_unmap(p_addr);
888 }
889 }
890 spin_unlock_irq(lock: &b->bm_lock);
891}
892
893/* set all bits in the bitmap */
894void drbd_bm_set_all(struct drbd_device *device)
895{
896 struct drbd_bitmap *b = device->bitmap;
897 if (!expect(device, b))
898 return;
899 if (!expect(device, b->bm_pages))
900 return;
901
902 spin_lock_irq(lock: &b->bm_lock);
903 bm_memset(b, offset: 0, c: 0xff, len: b->bm_words);
904 (void)bm_clear_surplus(b);
905 b->bm_set = b->bm_bits;
906 spin_unlock_irq(lock: &b->bm_lock);
907}
908
909/* clear all bits in the bitmap */
910void drbd_bm_clear_all(struct drbd_device *device)
911{
912 struct drbd_bitmap *b = device->bitmap;
913 if (!expect(device, b))
914 return;
915 if (!expect(device, b->bm_pages))
916 return;
917
918 spin_lock_irq(lock: &b->bm_lock);
919 bm_memset(b, offset: 0, c: 0, len: b->bm_words);
920 b->bm_set = 0;
921 spin_unlock_irq(lock: &b->bm_lock);
922}
923
924static void drbd_bm_aio_ctx_destroy(struct kref *kref)
925{
926 struct drbd_bm_aio_ctx *ctx = container_of(kref, struct drbd_bm_aio_ctx, kref);
927 unsigned long flags;
928
929 spin_lock_irqsave(&ctx->device->resource->req_lock, flags);
930 list_del(entry: &ctx->list);
931 spin_unlock_irqrestore(lock: &ctx->device->resource->req_lock, flags);
932 put_ldev(device: ctx->device);
933 kfree(objp: ctx);
934}
935
936/* bv_page may be a copy, or may be the original */
937static void drbd_bm_endio(struct bio *bio)
938{
939 struct drbd_bm_aio_ctx *ctx = bio->bi_private;
940 struct drbd_device *device = ctx->device;
941 struct drbd_bitmap *b = device->bitmap;
942 unsigned int idx = bm_page_to_idx(page: bio_first_page_all(bio));
943
944 if ((ctx->flags & BM_AIO_COPY_PAGES) == 0 &&
945 !bm_test_page_unchanged(page: b->bm_pages[idx]))
946 drbd_warn(device, "bitmap page idx %u changed during IO!\n", idx);
947
948 if (bio->bi_status) {
949 /* ctx error will hold the completed-last non-zero error code,
950 * in case error codes differ. */
951 ctx->error = blk_status_to_errno(status: bio->bi_status);
952 bm_set_page_io_err(page: b->bm_pages[idx]);
953 /* Not identical to on disk version of it.
954 * Is BM_PAGE_IO_ERROR enough? */
955 if (drbd_ratelimit())
956 drbd_err(device, "IO ERROR %d on bitmap page idx %u\n",
957 bio->bi_status, idx);
958 } else {
959 bm_clear_page_io_err(page: b->bm_pages[idx]);
960 dynamic_drbd_dbg(device, "bitmap page idx %u completed\n", idx);
961 }
962
963 bm_page_unlock_io(device, page_nr: idx);
964
965 if (ctx->flags & BM_AIO_COPY_PAGES)
966 mempool_free(element: bio->bi_io_vec[0].bv_page, pool: &drbd_md_io_page_pool);
967
968 bio_put(bio);
969
970 if (atomic_dec_and_test(v: &ctx->in_flight)) {
971 ctx->done = 1;
972 wake_up(&device->misc_wait);
973 kref_put(kref: &ctx->kref, release: &drbd_bm_aio_ctx_destroy);
974 }
975}
976
977/* For the layout, see comment above drbd_md_set_sector_offsets(). */
978static inline sector_t drbd_md_last_bitmap_sector(struct drbd_backing_dev *bdev)
979{
980 switch (bdev->md.meta_dev_idx) {
981 case DRBD_MD_INDEX_INTERNAL:
982 case DRBD_MD_INDEX_FLEX_INT:
983 return bdev->md.md_offset + bdev->md.al_offset -1;
984 case DRBD_MD_INDEX_FLEX_EXT:
985 default:
986 return bdev->md.md_offset + bdev->md.md_size_sect -1;
987 }
988}
989
990static void bm_page_io_async(struct drbd_bm_aio_ctx *ctx, int page_nr) __must_hold(local)
991{
992 struct drbd_device *device = ctx->device;
993 enum req_op op = ctx->flags & BM_AIO_READ ? REQ_OP_READ : REQ_OP_WRITE;
994 struct drbd_bitmap *b = device->bitmap;
995 struct bio *bio;
996 struct page *page;
997 sector_t last_bm_sect;
998 sector_t first_bm_sect;
999 sector_t on_disk_sector;
1000 unsigned int len;
1001
1002 first_bm_sect = device->ldev->md.md_offset + device->ldev->md.bm_offset;
1003 on_disk_sector = first_bm_sect + (((sector_t)page_nr) << (PAGE_SHIFT-SECTOR_SHIFT));
1004
1005 /* this might happen with very small
1006 * flexible external meta data device,
1007 * or with PAGE_SIZE > 4k */
1008 last_bm_sect = drbd_md_last_bitmap_sector(bdev: device->ldev);
1009 if (first_bm_sect <= on_disk_sector && last_bm_sect >= on_disk_sector) {
1010 sector_t len_sect = last_bm_sect - on_disk_sector + 1;
1011 if (len_sect < PAGE_SIZE/SECTOR_SIZE)
1012 len = (unsigned int)len_sect*SECTOR_SIZE;
1013 else
1014 len = PAGE_SIZE;
1015 } else {
1016 if (drbd_ratelimit()) {
1017 drbd_err(device, "Invalid offset during on-disk bitmap access: "
1018 "page idx %u, sector %llu\n", page_nr, on_disk_sector);
1019 }
1020 ctx->error = -EIO;
1021 bm_set_page_io_err(page: b->bm_pages[page_nr]);
1022 if (atomic_dec_and_test(v: &ctx->in_flight)) {
1023 ctx->done = 1;
1024 wake_up(&device->misc_wait);
1025 kref_put(kref: &ctx->kref, release: &drbd_bm_aio_ctx_destroy);
1026 }
1027 return;
1028 }
1029
1030 /* serialize IO on this page */
1031 bm_page_lock_io(device, page_nr);
1032 /* before memcpy and submit,
1033 * so it can be redirtied any time */
1034 bm_set_page_unchanged(page: b->bm_pages[page_nr]);
1035
1036 if (ctx->flags & BM_AIO_COPY_PAGES) {
1037 page = mempool_alloc(&drbd_md_io_page_pool,
1038 GFP_NOIO | __GFP_HIGHMEM);
1039 copy_highpage(to: page, from: b->bm_pages[page_nr]);
1040 bm_store_page_idx(page, idx: page_nr);
1041 } else
1042 page = b->bm_pages[page_nr];
1043 bio = bio_alloc_bioset(bdev: device->ldev->md_bdev, nr_vecs: 1, opf: op, GFP_NOIO,
1044 bs: &drbd_md_io_bio_set);
1045 bio->bi_iter.bi_sector = on_disk_sector;
1046 __bio_add_page(bio, page, len, off: 0);
1047 bio->bi_private = ctx;
1048 bio->bi_end_io = drbd_bm_endio;
1049
1050 if (drbd_insert_fault(device, type: (op == REQ_OP_WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD)) {
1051 bio_io_error(bio);
1052 } else {
1053 submit_bio(bio);
1054 /* this should not count as user activity and cause the
1055 * resync to throttle -- see drbd_rs_should_slow_down(). */
1056 atomic_add(i: len >> 9, v: &device->rs_sect_ev);
1057 }
1058}
1059
1060/*
1061 * bm_rw: read/write the whole bitmap from/to its on disk location.
1062 */
1063static int bm_rw(struct drbd_device *device, const unsigned int flags, unsigned lazy_writeout_upper_idx) __must_hold(local)
1064{
1065 struct drbd_bm_aio_ctx *ctx;
1066 struct drbd_bitmap *b = device->bitmap;
1067 unsigned int num_pages, i, count = 0;
1068 unsigned long now;
1069 char ppb[10];
1070 int err = 0;
1071
1072 /*
1073 * We are protected against bitmap disappearing/resizing by holding an
1074 * ldev reference (caller must have called get_ldev()).
1075 * For read/write, we are protected against changes to the bitmap by
1076 * the bitmap lock (see drbd_bitmap_io).
1077 * For lazy writeout, we don't care for ongoing changes to the bitmap,
1078 * as we submit copies of pages anyways.
1079 */
1080
1081 ctx = kmalloc(sizeof(struct drbd_bm_aio_ctx), GFP_NOIO);
1082 if (!ctx)
1083 return -ENOMEM;
1084
1085 *ctx = (struct drbd_bm_aio_ctx) {
1086 .device = device,
1087 .start_jif = jiffies,
1088 .in_flight = ATOMIC_INIT(1),
1089 .done = 0,
1090 .flags = flags,
1091 .error = 0,
1092 .kref = KREF_INIT(2),
1093 };
1094
1095 if (!get_ldev_if_state(device, D_ATTACHING)) { /* put is in drbd_bm_aio_ctx_destroy() */
1096 drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in bm_rw()\n");
1097 kfree(objp: ctx);
1098 return -ENODEV;
1099 }
1100 /* Here D_ATTACHING is sufficient since drbd_bm_read() is called only from
1101 drbd_adm_attach(), after device->ldev was assigned. */
1102
1103 if (0 == (ctx->flags & ~BM_AIO_READ))
1104 WARN_ON(!(BM_LOCKED_MASK & b->bm_flags));
1105
1106 spin_lock_irq(lock: &device->resource->req_lock);
1107 list_add_tail(new: &ctx->list, head: &device->pending_bitmap_io);
1108 spin_unlock_irq(lock: &device->resource->req_lock);
1109
1110 num_pages = b->bm_number_of_pages;
1111
1112 now = jiffies;
1113
1114 /* let the layers below us try to merge these bios... */
1115
1116 if (flags & BM_AIO_READ) {
1117 for (i = 0; i < num_pages; i++) {
1118 atomic_inc(v: &ctx->in_flight);
1119 bm_page_io_async(ctx, page_nr: i);
1120 ++count;
1121 cond_resched();
1122 }
1123 } else if (flags & BM_AIO_WRITE_HINTED) {
1124 /* ASSERT: BM_AIO_WRITE_ALL_PAGES is not set. */
1125 unsigned int hint;
1126 for (hint = 0; hint < b->n_bitmap_hints; hint++) {
1127 i = b->al_bitmap_hints[hint];
1128 if (i >= num_pages) /* == -1U: no hint here. */
1129 continue;
1130 /* Several AL-extents may point to the same page. */
1131 if (!test_and_clear_bit(BM_PAGE_HINT_WRITEOUT,
1132 addr: &page_private(b->bm_pages[i])))
1133 continue;
1134 /* Has it even changed? */
1135 if (bm_test_page_unchanged(page: b->bm_pages[i]))
1136 continue;
1137 atomic_inc(v: &ctx->in_flight);
1138 bm_page_io_async(ctx, page_nr: i);
1139 ++count;
1140 }
1141 } else {
1142 for (i = 0; i < num_pages; i++) {
1143 /* ignore completely unchanged pages */
1144 if (lazy_writeout_upper_idx && i == lazy_writeout_upper_idx)
1145 break;
1146 if (!(flags & BM_AIO_WRITE_ALL_PAGES) &&
1147 bm_test_page_unchanged(page: b->bm_pages[i])) {
1148 dynamic_drbd_dbg(device, "skipped bm write for idx %u\n", i);
1149 continue;
1150 }
1151 /* during lazy writeout,
1152 * ignore those pages not marked for lazy writeout. */
1153 if (lazy_writeout_upper_idx &&
1154 !bm_test_page_lazy_writeout(page: b->bm_pages[i])) {
1155 dynamic_drbd_dbg(device, "skipped bm lazy write for idx %u\n", i);
1156 continue;
1157 }
1158 atomic_inc(v: &ctx->in_flight);
1159 bm_page_io_async(ctx, page_nr: i);
1160 ++count;
1161 cond_resched();
1162 }
1163 }
1164
1165 /*
1166 * We initialize ctx->in_flight to one to make sure drbd_bm_endio
1167 * will not set ctx->done early, and decrement / test it here. If there
1168 * are still some bios in flight, we need to wait for them here.
1169 * If all IO is done already (or nothing had been submitted), there is
1170 * no need to wait. Still, we need to put the kref associated with the
1171 * "in_flight reached zero, all done" event.
1172 */
1173 if (!atomic_dec_and_test(v: &ctx->in_flight))
1174 wait_until_done_or_force_detached(device, bdev: device->ldev, done: &ctx->done);
1175 else
1176 kref_put(kref: &ctx->kref, release: &drbd_bm_aio_ctx_destroy);
1177
1178 /* summary for global bitmap IO */
1179 if (flags == 0) {
1180 unsigned int ms = jiffies_to_msecs(j: jiffies - now);
1181 if (ms > 5) {
1182 drbd_info(device, "bitmap %s of %u pages took %u ms\n",
1183 (flags & BM_AIO_READ) ? "READ" : "WRITE",
1184 count, ms);
1185 }
1186 }
1187
1188 if (ctx->error) {
1189 drbd_alert(device, "we had at least one MD IO ERROR during bitmap IO\n");
1190 drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR);
1191 err = -EIO; /* ctx->error ? */
1192 }
1193
1194 if (atomic_read(v: &ctx->in_flight))
1195 err = -EIO; /* Disk timeout/force-detach during IO... */
1196
1197 now = jiffies;
1198 if (flags & BM_AIO_READ) {
1199 b->bm_set = bm_count_bits(b);
1200 drbd_info(device, "recounting of set bits took additional %lu jiffies\n",
1201 jiffies - now);
1202 }
1203 now = b->bm_set;
1204
1205 if ((flags & ~BM_AIO_READ) == 0)
1206 drbd_info(device, "%s (%lu bits) marked out-of-sync by on disk bit-map.\n",
1207 ppsize(ppb, now << (BM_BLOCK_SHIFT-10)), now);
1208
1209 kref_put(kref: &ctx->kref, release: &drbd_bm_aio_ctx_destroy);
1210 return err;
1211}
1212
1213/*
1214 * drbd_bm_read() - Read the whole bitmap from its on disk location.
1215 * @device: DRBD device.
1216 */
1217int drbd_bm_read(struct drbd_device *device,
1218 struct drbd_peer_device *peer_device) __must_hold(local)
1219
1220{
1221 return bm_rw(device, BM_AIO_READ, lazy_writeout_upper_idx: 0);
1222}
1223
1224/*
1225 * drbd_bm_write() - Write the whole bitmap to its on disk location.
1226 * @device: DRBD device.
1227 *
1228 * Will only write pages that have changed since last IO.
1229 */
1230int drbd_bm_write(struct drbd_device *device,
1231 struct drbd_peer_device *peer_device) __must_hold(local)
1232{
1233 return bm_rw(device, flags: 0, lazy_writeout_upper_idx: 0);
1234}
1235
1236/*
1237 * drbd_bm_write_all() - Write the whole bitmap to its on disk location.
1238 * @device: DRBD device.
1239 *
1240 * Will write all pages.
1241 */
1242int drbd_bm_write_all(struct drbd_device *device,
1243 struct drbd_peer_device *peer_device) __must_hold(local)
1244{
1245 return bm_rw(device, BM_AIO_WRITE_ALL_PAGES, lazy_writeout_upper_idx: 0);
1246}
1247
1248/**
1249 * drbd_bm_write_lazy() - Write bitmap pages 0 to @upper_idx-1, if they have changed.
1250 * @device: DRBD device.
1251 * @upper_idx: 0: write all changed pages; +ve: page index to stop scanning for changed pages
1252 */
1253int drbd_bm_write_lazy(struct drbd_device *device, unsigned upper_idx) __must_hold(local)
1254{
1255 return bm_rw(device, BM_AIO_COPY_PAGES, lazy_writeout_upper_idx: upper_idx);
1256}
1257
1258/*
1259 * drbd_bm_write_copy_pages() - Write the whole bitmap to its on disk location.
1260 * @device: DRBD device.
1261 *
1262 * Will only write pages that have changed since last IO.
1263 * In contrast to drbd_bm_write(), this will copy the bitmap pages
1264 * to temporary writeout pages. It is intended to trigger a full write-out
1265 * while still allowing the bitmap to change, for example if a resync or online
1266 * verify is aborted due to a failed peer disk, while local IO continues, or
1267 * pending resync acks are still being processed.
1268 */
1269int drbd_bm_write_copy_pages(struct drbd_device *device,
1270 struct drbd_peer_device *peer_device) __must_hold(local)
1271{
1272 return bm_rw(device, BM_AIO_COPY_PAGES, lazy_writeout_upper_idx: 0);
1273}
1274
1275/*
1276 * drbd_bm_write_hinted() - Write bitmap pages with "hint" marks, if they have changed.
1277 * @device: DRBD device.
1278 */
1279int drbd_bm_write_hinted(struct drbd_device *device) __must_hold(local)
1280{
1281 return bm_rw(device, BM_AIO_WRITE_HINTED | BM_AIO_COPY_PAGES, lazy_writeout_upper_idx: 0);
1282}
1283
1284/* NOTE
1285 * find_first_bit returns int, we return unsigned long.
1286 * For this to work on 32bit arch with bitnumbers > (1<<32),
1287 * we'd need to return u64, and get a whole lot of other places
1288 * fixed where we still use unsigned long.
1289 *
1290 * this returns a bit number, NOT a sector!
1291 */
1292static unsigned long __bm_find_next(struct drbd_device *device, unsigned long bm_fo,
1293 const int find_zero_bit)
1294{
1295 struct drbd_bitmap *b = device->bitmap;
1296 unsigned long *p_addr;
1297 unsigned long bit_offset;
1298 unsigned i;
1299
1300
1301 if (bm_fo > b->bm_bits) {
1302 drbd_err(device, "bm_fo=%lu bm_bits=%lu\n", bm_fo, b->bm_bits);
1303 bm_fo = DRBD_END_OF_BITMAP;
1304 } else {
1305 while (bm_fo < b->bm_bits) {
1306 /* bit offset of the first bit in the page */
1307 bit_offset = bm_fo & ~BITS_PER_PAGE_MASK;
1308 p_addr = __bm_map_pidx(b, idx: bm_bit_to_page_idx(b, bitnr: bm_fo));
1309
1310 if (find_zero_bit)
1311 i = find_next_zero_bit_le(addr: p_addr,
1312 PAGE_SIZE*8, offset: bm_fo & BITS_PER_PAGE_MASK);
1313 else
1314 i = find_next_bit_le(addr: p_addr,
1315 PAGE_SIZE*8, offset: bm_fo & BITS_PER_PAGE_MASK);
1316
1317 __bm_unmap(p_addr);
1318 if (i < PAGE_SIZE*8) {
1319 bm_fo = bit_offset + i;
1320 if (bm_fo >= b->bm_bits)
1321 break;
1322 goto found;
1323 }
1324 bm_fo = bit_offset + PAGE_SIZE*8;
1325 }
1326 bm_fo = DRBD_END_OF_BITMAP;
1327 }
1328 found:
1329 return bm_fo;
1330}
1331
1332static unsigned long bm_find_next(struct drbd_device *device,
1333 unsigned long bm_fo, const int find_zero_bit)
1334{
1335 struct drbd_bitmap *b = device->bitmap;
1336 unsigned long i = DRBD_END_OF_BITMAP;
1337
1338 if (!expect(device, b))
1339 return i;
1340 if (!expect(device, b->bm_pages))
1341 return i;
1342
1343 spin_lock_irq(lock: &b->bm_lock);
1344 if (BM_DONT_TEST & b->bm_flags)
1345 bm_print_lock_info(device);
1346
1347 i = __bm_find_next(device, bm_fo, find_zero_bit);
1348
1349 spin_unlock_irq(lock: &b->bm_lock);
1350 return i;
1351}
1352
1353unsigned long drbd_bm_find_next(struct drbd_device *device, unsigned long bm_fo)
1354{
1355 return bm_find_next(device, bm_fo, find_zero_bit: 0);
1356}
1357
1358#if 0
1359/* not yet needed for anything. */
1360unsigned long drbd_bm_find_next_zero(struct drbd_device *device, unsigned long bm_fo)
1361{
1362 return bm_find_next(device, bm_fo, 1);
1363}
1364#endif
1365
1366/* does not spin_lock_irqsave.
1367 * you must take drbd_bm_lock() first */
1368unsigned long _drbd_bm_find_next(struct drbd_device *device, unsigned long bm_fo)
1369{
1370 /* WARN_ON(!(BM_DONT_SET & device->b->bm_flags)); */
1371 return __bm_find_next(device, bm_fo, find_zero_bit: 0);
1372}
1373
1374unsigned long _drbd_bm_find_next_zero(struct drbd_device *device, unsigned long bm_fo)
1375{
1376 /* WARN_ON(!(BM_DONT_SET & device->b->bm_flags)); */
1377 return __bm_find_next(device, bm_fo, find_zero_bit: 1);
1378}
1379
1380/* returns number of bits actually changed.
1381 * for val != 0, we change 0 -> 1, return code positive
1382 * for val == 0, we change 1 -> 0, return code negative
1383 * wants bitnr, not sector.
1384 * expected to be called for only a few bits (e - s about BITS_PER_LONG).
1385 * Must hold bitmap lock already. */
1386static int __bm_change_bits_to(struct drbd_device *device, const unsigned long s,
1387 unsigned long e, int val)
1388{
1389 struct drbd_bitmap *b = device->bitmap;
1390 unsigned long *p_addr = NULL;
1391 unsigned long bitnr;
1392 unsigned int last_page_nr = -1U;
1393 int c = 0;
1394 int changed_total = 0;
1395
1396 if (e >= b->bm_bits) {
1397 drbd_err(device, "ASSERT FAILED: bit_s=%lu bit_e=%lu bm_bits=%lu\n",
1398 s, e, b->bm_bits);
1399 e = b->bm_bits ? b->bm_bits -1 : 0;
1400 }
1401 for (bitnr = s; bitnr <= e; bitnr++) {
1402 unsigned int page_nr = bm_bit_to_page_idx(b, bitnr);
1403 if (page_nr != last_page_nr) {
1404 if (p_addr)
1405 __bm_unmap(p_addr);
1406 if (c < 0)
1407 bm_set_page_lazy_writeout(page: b->bm_pages[last_page_nr]);
1408 else if (c > 0)
1409 bm_set_page_need_writeout(page: b->bm_pages[last_page_nr]);
1410 changed_total += c;
1411 c = 0;
1412 p_addr = __bm_map_pidx(b, idx: page_nr);
1413 last_page_nr = page_nr;
1414 }
1415 if (val)
1416 c += (0 == __test_and_set_bit_le(nr: bitnr & BITS_PER_PAGE_MASK, addr: p_addr));
1417 else
1418 c -= (0 != __test_and_clear_bit_le(nr: bitnr & BITS_PER_PAGE_MASK, addr: p_addr));
1419 }
1420 if (p_addr)
1421 __bm_unmap(p_addr);
1422 if (c < 0)
1423 bm_set_page_lazy_writeout(page: b->bm_pages[last_page_nr]);
1424 else if (c > 0)
1425 bm_set_page_need_writeout(page: b->bm_pages[last_page_nr]);
1426 changed_total += c;
1427 b->bm_set += changed_total;
1428 return changed_total;
1429}
1430
1431/* returns number of bits actually changed.
1432 * for val != 0, we change 0 -> 1, return code positive
1433 * for val == 0, we change 1 -> 0, return code negative
1434 * wants bitnr, not sector */
1435static int bm_change_bits_to(struct drbd_device *device, const unsigned long s,
1436 const unsigned long e, int val)
1437{
1438 unsigned long flags;
1439 struct drbd_bitmap *b = device->bitmap;
1440 int c = 0;
1441
1442 if (!expect(device, b))
1443 return 1;
1444 if (!expect(device, b->bm_pages))
1445 return 0;
1446
1447 spin_lock_irqsave(&b->bm_lock, flags);
1448 if ((val ? BM_DONT_SET : BM_DONT_CLEAR) & b->bm_flags)
1449 bm_print_lock_info(device);
1450
1451 c = __bm_change_bits_to(device, s, e, val);
1452
1453 spin_unlock_irqrestore(lock: &b->bm_lock, flags);
1454 return c;
1455}
1456
1457/* returns number of bits changed 0 -> 1 */
1458int drbd_bm_set_bits(struct drbd_device *device, const unsigned long s, const unsigned long e)
1459{
1460 return bm_change_bits_to(device, s, e, val: 1);
1461}
1462
1463/* returns number of bits changed 1 -> 0 */
1464int drbd_bm_clear_bits(struct drbd_device *device, const unsigned long s, const unsigned long e)
1465{
1466 return -bm_change_bits_to(device, s, e, val: 0);
1467}
1468
1469/* sets all bits in full words,
1470 * from first_word up to, but not including, last_word */
1471static inline void bm_set_full_words_within_one_page(struct drbd_bitmap *b,
1472 int page_nr, int first_word, int last_word)
1473{
1474 int i;
1475 int bits;
1476 int changed = 0;
1477 unsigned long *paddr = kmap_atomic(page: b->bm_pages[page_nr]);
1478
1479 /* I think it is more cache line friendly to hweight_long then set to ~0UL,
1480 * than to first bitmap_weight() all words, then bitmap_fill() all words */
1481 for (i = first_word; i < last_word; i++) {
1482 bits = hweight_long(w: paddr[i]);
1483 paddr[i] = ~0UL;
1484 changed += BITS_PER_LONG - bits;
1485 }
1486 kunmap_atomic(paddr);
1487 if (changed) {
1488 /* We only need lazy writeout, the information is still in the
1489 * remote bitmap as well, and is reconstructed during the next
1490 * bitmap exchange, if lost locally due to a crash. */
1491 bm_set_page_lazy_writeout(page: b->bm_pages[page_nr]);
1492 b->bm_set += changed;
1493 }
1494}
1495
1496/* Same thing as drbd_bm_set_bits,
1497 * but more efficient for a large bit range.
1498 * You must first drbd_bm_lock().
1499 * Can be called to set the whole bitmap in one go.
1500 * Sets bits from s to e _inclusive_. */
1501void _drbd_bm_set_bits(struct drbd_device *device, const unsigned long s, const unsigned long e)
1502{
1503 /* First set_bit from the first bit (s)
1504 * up to the next long boundary (sl),
1505 * then assign full words up to the last long boundary (el),
1506 * then set_bit up to and including the last bit (e).
1507 *
1508 * Do not use memset, because we must account for changes,
1509 * so we need to loop over the words with hweight() anyways.
1510 */
1511 struct drbd_bitmap *b = device->bitmap;
1512 unsigned long sl = ALIGN(s,BITS_PER_LONG);
1513 unsigned long el = (e+1) & ~((unsigned long)BITS_PER_LONG-1);
1514 int first_page;
1515 int last_page;
1516 int page_nr;
1517 int first_word;
1518 int last_word;
1519
1520 if (e - s <= 3*BITS_PER_LONG) {
1521 /* don't bother; el and sl may even be wrong. */
1522 spin_lock_irq(lock: &b->bm_lock);
1523 __bm_change_bits_to(device, s, e, val: 1);
1524 spin_unlock_irq(lock: &b->bm_lock);
1525 return;
1526 }
1527
1528 /* difference is large enough that we can trust sl and el */
1529
1530 spin_lock_irq(lock: &b->bm_lock);
1531
1532 /* bits filling the current long */
1533 if (sl)
1534 __bm_change_bits_to(device, s, e: sl-1, val: 1);
1535
1536 first_page = sl >> (3 + PAGE_SHIFT);
1537 last_page = el >> (3 + PAGE_SHIFT);
1538
1539 /* MLPP: modulo longs per page */
1540 /* LWPP: long words per page */
1541 first_word = MLPP(sl >> LN2_BPL);
1542 last_word = LWPP;
1543
1544 /* first and full pages, unless first page == last page */
1545 for (page_nr = first_page; page_nr < last_page; page_nr++) {
1546 bm_set_full_words_within_one_page(b: device->bitmap, page_nr, first_word, last_word);
1547 spin_unlock_irq(lock: &b->bm_lock);
1548 cond_resched();
1549 first_word = 0;
1550 spin_lock_irq(lock: &b->bm_lock);
1551 }
1552 /* last page (respectively only page, for first page == last page) */
1553 last_word = MLPP(el >> LN2_BPL);
1554
1555 /* consider bitmap->bm_bits = 32768, bitmap->bm_number_of_pages = 1. (or multiples).
1556 * ==> e = 32767, el = 32768, last_page = 2,
1557 * and now last_word = 0.
1558 * We do not want to touch last_page in this case,
1559 * as we did not allocate it, it is not present in bitmap->bm_pages.
1560 */
1561 if (last_word)
1562 bm_set_full_words_within_one_page(b: device->bitmap, page_nr: last_page, first_word, last_word);
1563
1564 /* possibly trailing bits.
1565 * example: (e & 63) == 63, el will be e+1.
1566 * if that even was the very last bit,
1567 * it would trigger an assert in __bm_change_bits_to()
1568 */
1569 if (el <= e)
1570 __bm_change_bits_to(device, s: el, e, val: 1);
1571 spin_unlock_irq(lock: &b->bm_lock);
1572}
1573
1574/* returns bit state
1575 * wants bitnr, NOT sector.
1576 * inherently racy... area needs to be locked by means of {al,rs}_lru
1577 * 1 ... bit set
1578 * 0 ... bit not set
1579 * -1 ... first out of bounds access, stop testing for bits!
1580 */
1581int drbd_bm_test_bit(struct drbd_device *device, const unsigned long bitnr)
1582{
1583 unsigned long flags;
1584 struct drbd_bitmap *b = device->bitmap;
1585 unsigned long *p_addr;
1586 int i;
1587
1588 if (!expect(device, b))
1589 return 0;
1590 if (!expect(device, b->bm_pages))
1591 return 0;
1592
1593 spin_lock_irqsave(&b->bm_lock, flags);
1594 if (BM_DONT_TEST & b->bm_flags)
1595 bm_print_lock_info(device);
1596 if (bitnr < b->bm_bits) {
1597 p_addr = bm_map_pidx(b, idx: bm_bit_to_page_idx(b, bitnr));
1598 i = test_bit_le(nr: bitnr & BITS_PER_PAGE_MASK, addr: p_addr) ? 1 : 0;
1599 bm_unmap(p_addr);
1600 } else if (bitnr == b->bm_bits) {
1601 i = -1;
1602 } else { /* (bitnr > b->bm_bits) */
1603 drbd_err(device, "bitnr=%lu > bm_bits=%lu\n", bitnr, b->bm_bits);
1604 i = 0;
1605 }
1606
1607 spin_unlock_irqrestore(lock: &b->bm_lock, flags);
1608 return i;
1609}
1610
1611/* returns number of bits set in the range [s, e] */
1612int drbd_bm_count_bits(struct drbd_device *device, const unsigned long s, const unsigned long e)
1613{
1614 unsigned long flags;
1615 struct drbd_bitmap *b = device->bitmap;
1616 unsigned long *p_addr = NULL;
1617 unsigned long bitnr;
1618 unsigned int page_nr = -1U;
1619 int c = 0;
1620
1621 /* If this is called without a bitmap, that is a bug. But just to be
1622 * robust in case we screwed up elsewhere, in that case pretend there
1623 * was one dirty bit in the requested area, so we won't try to do a
1624 * local read there (no bitmap probably implies no disk) */
1625 if (!expect(device, b))
1626 return 1;
1627 if (!expect(device, b->bm_pages))
1628 return 1;
1629
1630 spin_lock_irqsave(&b->bm_lock, flags);
1631 if (BM_DONT_TEST & b->bm_flags)
1632 bm_print_lock_info(device);
1633 for (bitnr = s; bitnr <= e; bitnr++) {
1634 unsigned int idx = bm_bit_to_page_idx(b, bitnr);
1635 if (page_nr != idx) {
1636 page_nr = idx;
1637 if (p_addr)
1638 bm_unmap(p_addr);
1639 p_addr = bm_map_pidx(b, idx);
1640 }
1641 if (expect(device, bitnr < b->bm_bits))
1642 c += (0 != test_bit_le(nr: bitnr - (page_nr << (PAGE_SHIFT+3)), addr: p_addr));
1643 else
1644 drbd_err(device, "bitnr=%lu bm_bits=%lu\n", bitnr, b->bm_bits);
1645 }
1646 if (p_addr)
1647 bm_unmap(p_addr);
1648 spin_unlock_irqrestore(lock: &b->bm_lock, flags);
1649 return c;
1650}
1651
1652
1653/* inherently racy...
1654 * return value may be already out-of-date when this function returns.
1655 * but the general usage is that this is only use during a cstate when bits are
1656 * only cleared, not set, and typically only care for the case when the return
1657 * value is zero, or we already "locked" this "bitmap extent" by other means.
1658 *
1659 * enr is bm-extent number, since we chose to name one sector (512 bytes)
1660 * worth of the bitmap a "bitmap extent".
1661 *
1662 * TODO
1663 * I think since we use it like a reference count, we should use the real
1664 * reference count of some bitmap extent element from some lru instead...
1665 *
1666 */
1667int drbd_bm_e_weight(struct drbd_device *device, unsigned long enr)
1668{
1669 struct drbd_bitmap *b = device->bitmap;
1670 int count, s, e;
1671 unsigned long flags;
1672 unsigned long *p_addr, *bm;
1673
1674 if (!expect(device, b))
1675 return 0;
1676 if (!expect(device, b->bm_pages))
1677 return 0;
1678
1679 spin_lock_irqsave(&b->bm_lock, flags);
1680 if (BM_DONT_TEST & b->bm_flags)
1681 bm_print_lock_info(device);
1682
1683 s = S2W(enr);
1684 e = min((size_t)S2W(enr+1), b->bm_words);
1685 count = 0;
1686 if (s < b->bm_words) {
1687 int n = e-s;
1688 p_addr = bm_map_pidx(b, idx: bm_word_to_page_idx(b, long_nr: s));
1689 bm = p_addr + MLPP(s);
1690 count += bitmap_weight(src: bm, nbits: n * BITS_PER_LONG);
1691 bm_unmap(p_addr);
1692 } else {
1693 drbd_err(device, "start offset (%d) too large in drbd_bm_e_weight\n", s);
1694 }
1695 spin_unlock_irqrestore(lock: &b->bm_lock, flags);
1696 return count;
1697}
1698

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