4 This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
6 Copyright (C) 2004-2008, LINBIT Information Technologies GmbH.
7 Copyright (C) 2004-2008, Philipp Reisner <philipp.reisner@linbit.com>.
8 Copyright (C) 2004-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
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)
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.
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.
25 #include <linux/bitops.h>
26 #include <linux/vmalloc.h>
27 #include <linux/string.h>
28 #include <linux/drbd.h>
29 #include <linux/slab.h>
30 #include <asm/kmap_types.h>
35 /* OPAQUE outside this file!
36 * interface defined in drbd_int.h
39 * function name drbd_bm_... => used elsewhere, "public".
40 * function name bm_... => internal to implementation, "private".
46 * We want to support >= peta byte of backend storage, while for now still using
47 * a granularity of one bit per 4KiB of storage.
48 * 1 << 50 bytes backend storage (1 PiB)
49 * 1 << (50 - 12) bits needed
50 * 38 --> we need u64 to index and count bits
51 * 1 << (38 - 3) bitmap bytes needed
52 * 35 --> we still need u64 to index and count bytes
53 * (that's 32 GiB of bitmap for 1 PiB storage)
54 * 1 << (35 - 2) 32bit longs needed
55 * 33 --> we'd even need u64 to index and count 32bit long words.
56 * 1 << (35 - 3) 64bit longs needed
57 * 32 --> we could get away with a 32bit unsigned int to index and count
58 * 64bit long words, but I rather stay with unsigned long for now.
59 * We probably should neither count nor point to bytes or long words
60 * directly, but either by bitnumber, or by page index and offset.
62 * 22 --> we need that much 4KiB pages of bitmap.
63 * 1 << (22 + 3) --> on a 64bit arch,
64 * we need 32 MiB to store the array of page pointers.
66 * Because I'm lazy, and because the resulting patch was too large, too ugly
67 * and still incomplete, on 32bit we still "only" support 16 TiB (minus some),
68 * (1 << 32) bits * 4k storage.
71 * bitmap storage and IO:
72 * Bitmap is stored little endian on disk, and is kept little endian in
73 * core memory. Currently we still hold the full bitmap in core as long
74 * as we are "attached" to a local disk, which at 32 GiB for 1PiB storage
77 * We plan to reduce the amount of in-core bitmap pages by paging them in
78 * and out against their on-disk location as necessary, but need to make
79 * sure we don't cause too much meta data IO, and must not deadlock in
80 * tight memory situations. This needs some more work.
85 * Access to the *bm_pages is protected by bm_lock.
86 * It is safe to read the other members within the lock.
88 * drbd_bm_set_bits is called from bio_endio callbacks,
89 * We may be called with irq already disabled,
90 * so we need spin_lock_irqsave().
91 * And we need the kmap_atomic.
94 struct page **bm_pages;
97 /* see LIMITATIONS: above */
99 unsigned long bm_set; /* nr of set bits; THINK maybe atomic_t? */
100 unsigned long bm_bits;
102 size_t bm_number_of_pages;
103 sector_t bm_dev_capacity;
104 struct mutex bm_change; /* serializes resize operations */
106 wait_queue_head_t bm_io_wait; /* used to serialize IO of single pages */
108 enum bm_flag bm_flags;
110 /* debugging aid, in case we are still racy somewhere */
112 struct task_struct *bm_task;
115 #define bm_print_lock_info(m) __bm_print_lock_info(m, __func__)
116 static void __bm_print_lock_info(struct drbd_conf *mdev, const char *func)
118 struct drbd_bitmap *b = mdev->bitmap;
119 if (!__ratelimit(&drbd_ratelimit_state))
121 dev_err(DEV, "FIXME %s in %s, bitmap locked for '%s' by %s\n",
122 current == mdev->receiver.task ? "receiver" :
123 current == mdev->asender.task ? "asender" :
124 current == mdev->worker.task ? "worker" : current->comm,
125 func, b->bm_why ?: "?",
126 b->bm_task == mdev->receiver.task ? "receiver" :
127 b->bm_task == mdev->asender.task ? "asender" :
128 b->bm_task == mdev->worker.task ? "worker" : "?");
131 void drbd_bm_lock(struct drbd_conf *mdev, char *why, enum bm_flag flags)
133 struct drbd_bitmap *b = mdev->bitmap;
137 dev_err(DEV, "FIXME no bitmap in drbd_bm_lock!?\n");
141 trylock_failed = !mutex_trylock(&b->bm_change);
143 if (trylock_failed) {
144 dev_warn(DEV, "%s going to '%s' but bitmap already locked for '%s' by %s\n",
145 current == mdev->receiver.task ? "receiver" :
146 current == mdev->asender.task ? "asender" :
147 current == mdev->worker.task ? "worker" : current->comm,
148 why, b->bm_why ?: "?",
149 b->bm_task == mdev->receiver.task ? "receiver" :
150 b->bm_task == mdev->asender.task ? "asender" :
151 b->bm_task == mdev->worker.task ? "worker" : "?");
152 mutex_lock(&b->bm_change);
154 if (BM_LOCKED_MASK & b->bm_flags)
155 dev_err(DEV, "FIXME bitmap already locked in bm_lock\n");
156 b->bm_flags |= flags & BM_LOCKED_MASK;
159 b->bm_task = current;
162 void drbd_bm_unlock(struct drbd_conf *mdev)
164 struct drbd_bitmap *b = mdev->bitmap;
166 dev_err(DEV, "FIXME no bitmap in drbd_bm_unlock!?\n");
170 if (!(BM_LOCKED_MASK & mdev->bitmap->bm_flags))
171 dev_err(DEV, "FIXME bitmap not locked in bm_unlock\n");
173 b->bm_flags &= ~BM_LOCKED_MASK;
176 mutex_unlock(&b->bm_change);
179 /* we store some "meta" info about our pages in page->private */
180 /* at a granularity of 4k storage per bitmap bit:
181 * one peta byte storage: 1<<50 byte, 1<<38 * 4k storage blocks
183 * 1<<23 4k bitmap pages.
184 * Use 24 bits as page index, covers 2 peta byte storage
185 * at a granularity of 4k per bit.
186 * Used to report the failed page idx on io error from the endio handlers.
188 #define BM_PAGE_IDX_MASK ((1UL<<24)-1)
189 /* this page is currently read in, or written back */
190 #define BM_PAGE_IO_LOCK 31
191 /* if there has been an IO error for this page */
192 #define BM_PAGE_IO_ERROR 30
193 /* this is to be able to intelligently skip disk IO,
194 * set if bits have been set since last IO. */
195 #define BM_PAGE_NEED_WRITEOUT 29
196 /* to mark for lazy writeout once syncer cleared all clearable bits,
197 * we if bits have been cleared since last IO. */
198 #define BM_PAGE_LAZY_WRITEOUT 28
200 /* store_page_idx uses non-atomic assignment. It is only used directly after
201 * allocating the page. All other bm_set_page_* and bm_clear_page_* need to
202 * use atomic bit manipulation, as set_out_of_sync (and therefore bitmap
203 * changes) may happen from various contexts, and wait_on_bit/wake_up_bit
204 * requires it all to be atomic as well. */
205 static void bm_store_page_idx(struct page *page, unsigned long idx)
207 BUG_ON(0 != (idx & ~BM_PAGE_IDX_MASK));
208 set_page_private(page, idx);
211 static unsigned long bm_page_to_idx(struct page *page)
213 return page_private(page) & BM_PAGE_IDX_MASK;
216 /* As is very unlikely that the same page is under IO from more than one
217 * context, we can get away with a bit per page and one wait queue per bitmap.
219 static void bm_page_lock_io(struct drbd_conf *mdev, int page_nr)
221 struct drbd_bitmap *b = mdev->bitmap;
222 void *addr = &page_private(b->bm_pages[page_nr]);
223 wait_event(b->bm_io_wait, !test_and_set_bit(BM_PAGE_IO_LOCK, addr));
226 static void bm_page_unlock_io(struct drbd_conf *mdev, int page_nr)
228 struct drbd_bitmap *b = mdev->bitmap;
229 void *addr = &page_private(b->bm_pages[page_nr]);
230 clear_bit(BM_PAGE_IO_LOCK, addr);
231 smp_mb__after_clear_bit();
232 wake_up(&mdev->bitmap->bm_io_wait);
235 /* set _before_ submit_io, so it may be reset due to being changed
236 * while this page is in flight... will get submitted later again */
237 static void bm_set_page_unchanged(struct page *page)
240 clear_bit(BM_PAGE_NEED_WRITEOUT, &page_private(page));
241 clear_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page));
244 static void bm_set_page_need_writeout(struct page *page)
246 set_bit(BM_PAGE_NEED_WRITEOUT, &page_private(page));
249 static int bm_test_page_unchanged(struct page *page)
251 volatile const unsigned long *addr = &page_private(page);
252 return (*addr & ((1UL<<BM_PAGE_NEED_WRITEOUT)|(1UL<<BM_PAGE_LAZY_WRITEOUT))) == 0;
255 static void bm_set_page_io_err(struct page *page)
257 set_bit(BM_PAGE_IO_ERROR, &page_private(page));
260 static void bm_clear_page_io_err(struct page *page)
262 clear_bit(BM_PAGE_IO_ERROR, &page_private(page));
265 static void bm_set_page_lazy_writeout(struct page *page)
267 set_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page));
270 static int bm_test_page_lazy_writeout(struct page *page)
272 return test_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page));
275 /* on a 32bit box, this would allow for exactly (2<<38) bits. */
276 static unsigned int bm_word_to_page_idx(struct drbd_bitmap *b, unsigned long long_nr)
278 /* page_nr = (word*sizeof(long)) >> PAGE_SHIFT; */
279 unsigned int page_nr = long_nr >> (PAGE_SHIFT - LN2_BPL + 3);
280 BUG_ON(page_nr >= b->bm_number_of_pages);
284 static unsigned int bm_bit_to_page_idx(struct drbd_bitmap *b, u64 bitnr)
286 /* page_nr = (bitnr/8) >> PAGE_SHIFT; */
287 unsigned int page_nr = bitnr >> (PAGE_SHIFT + 3);
288 BUG_ON(page_nr >= b->bm_number_of_pages);
292 static unsigned long *__bm_map_pidx(struct drbd_bitmap *b, unsigned int idx)
294 struct page *page = b->bm_pages[idx];
295 return (unsigned long *) kmap_atomic(page);
298 static unsigned long *bm_map_pidx(struct drbd_bitmap *b, unsigned int idx)
300 return __bm_map_pidx(b, idx);
303 static void __bm_unmap(unsigned long *p_addr)
305 kunmap_atomic(p_addr);
308 static void bm_unmap(unsigned long *p_addr)
310 return __bm_unmap(p_addr);
313 /* long word offset of _bitmap_ sector */
314 #define S2W(s) ((s)<<(BM_EXT_SHIFT-BM_BLOCK_SHIFT-LN2_BPL))
315 /* word offset from start of bitmap to word number _in_page_
316 * modulo longs per page
317 #define MLPP(X) ((X) % (PAGE_SIZE/sizeof(long))
318 hm, well, Philipp thinks gcc might not optimize the % into & (... - 1)
321 #define MLPP(X) ((X) & ((PAGE_SIZE/sizeof(long))-1))
323 /* Long words per page */
324 #define LWPP (PAGE_SIZE/sizeof(long))
327 * actually most functions herein should take a struct drbd_bitmap*, not a
328 * struct drbd_conf*, but for the debug macros I like to have the mdev around
329 * to be able to report device specific.
333 static void bm_free_pages(struct page **pages, unsigned long number)
339 for (i = 0; i < number; i++) {
341 printk(KERN_ALERT "drbd: bm_free_pages tried to free "
342 "a NULL pointer; i=%lu n=%lu\n",
346 __free_page(pages[i]);
351 static void bm_vk_free(void *ptr, int v)
360 * "have" and "want" are NUMBER OF PAGES.
362 static struct page **bm_realloc_pages(struct drbd_bitmap *b, unsigned long want)
364 struct page **old_pages = b->bm_pages;
365 struct page **new_pages, *page;
366 unsigned int i, bytes, vmalloced = 0;
367 unsigned long have = b->bm_number_of_pages;
369 BUG_ON(have == 0 && old_pages != NULL);
370 BUG_ON(have != 0 && old_pages == NULL);
375 /* Trying kmalloc first, falling back to vmalloc.
376 * GFP_NOIO, as this is called while drbd IO is "suspended",
377 * and during resize or attach on diskless Primary,
378 * we must not block on IO to ourselves.
379 * Context is receiver thread or cqueue thread/dmsetup. */
380 bytes = sizeof(struct page *)*want;
381 new_pages = kzalloc(bytes, GFP_NOIO);
383 new_pages = __vmalloc(bytes,
384 GFP_NOIO | __GFP_HIGHMEM | __GFP_ZERO,
392 for (i = 0; i < have; i++)
393 new_pages[i] = old_pages[i];
394 for (; i < want; i++) {
395 page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
397 bm_free_pages(new_pages + have, i - have);
398 bm_vk_free(new_pages, vmalloced);
401 /* we want to know which page it is
402 * from the endio handlers */
403 bm_store_page_idx(page, i);
407 for (i = 0; i < want; i++)
408 new_pages[i] = old_pages[i];
409 /* NOT HERE, we are outside the spinlock!
410 bm_free_pages(old_pages + want, have - want);
415 b->bm_flags |= BM_P_VMALLOCED;
417 b->bm_flags &= ~BM_P_VMALLOCED;
423 * called on driver init only. TODO call when a device is created.
424 * allocates the drbd_bitmap, and stores it in mdev->bitmap.
426 int drbd_bm_init(struct drbd_conf *mdev)
428 struct drbd_bitmap *b = mdev->bitmap;
430 b = kzalloc(sizeof(struct drbd_bitmap), GFP_KERNEL);
433 spin_lock_init(&b->bm_lock);
434 mutex_init(&b->bm_change);
435 init_waitqueue_head(&b->bm_io_wait);
442 sector_t drbd_bm_capacity(struct drbd_conf *mdev)
444 ERR_IF(!mdev->bitmap) return 0;
445 return mdev->bitmap->bm_dev_capacity;
448 /* called on driver unload. TODO: call when a device is destroyed.
450 void drbd_bm_cleanup(struct drbd_conf *mdev)
452 ERR_IF (!mdev->bitmap) return;
453 bm_free_pages(mdev->bitmap->bm_pages, mdev->bitmap->bm_number_of_pages);
454 bm_vk_free(mdev->bitmap->bm_pages, (BM_P_VMALLOCED & mdev->bitmap->bm_flags));
460 * since (b->bm_bits % BITS_PER_LONG) != 0,
461 * this masks out the remaining bits.
462 * Returns the number of bits cleared.
464 #define BITS_PER_PAGE (1UL << (PAGE_SHIFT + 3))
465 #define BITS_PER_PAGE_MASK (BITS_PER_PAGE - 1)
466 #define BITS_PER_LONG_MASK (BITS_PER_LONG - 1)
467 static int bm_clear_surplus(struct drbd_bitmap *b)
470 unsigned long *p_addr, *bm;
474 /* number of bits modulo bits per page */
475 tmp = (b->bm_bits & BITS_PER_PAGE_MASK);
476 /* mask the used bits of the word containing the last bit */
477 mask = (1UL << (tmp & BITS_PER_LONG_MASK)) -1;
478 /* bitmap is always stored little endian,
479 * on disk and in core memory alike */
480 mask = cpu_to_lel(mask);
482 p_addr = bm_map_pidx(b, b->bm_number_of_pages - 1);
483 bm = p_addr + (tmp/BITS_PER_LONG);
485 /* If mask != 0, we are not exactly aligned, so bm now points
486 * to the long containing the last bit.
487 * If mask == 0, bm already points to the word immediately
488 * after the last (long word aligned) bit. */
489 cleared = hweight_long(*bm & ~mask);
494 if (BITS_PER_LONG == 32 && ((bm - p_addr) & 1) == 1) {
495 /* on a 32bit arch, we may need to zero out
496 * a padding long to align with a 64bit remote */
497 cleared += hweight_long(*bm);
504 static void bm_set_surplus(struct drbd_bitmap *b)
507 unsigned long *p_addr, *bm;
510 /* number of bits modulo bits per page */
511 tmp = (b->bm_bits & BITS_PER_PAGE_MASK);
512 /* mask the used bits of the word containing the last bit */
513 mask = (1UL << (tmp & BITS_PER_LONG_MASK)) -1;
514 /* bitmap is always stored little endian,
515 * on disk and in core memory alike */
516 mask = cpu_to_lel(mask);
518 p_addr = bm_map_pidx(b, b->bm_number_of_pages - 1);
519 bm = p_addr + (tmp/BITS_PER_LONG);
521 /* If mask != 0, we are not exactly aligned, so bm now points
522 * to the long containing the last bit.
523 * If mask == 0, bm already points to the word immediately
524 * after the last (long word aligned) bit. */
529 if (BITS_PER_LONG == 32 && ((bm - p_addr) & 1) == 1) {
530 /* on a 32bit arch, we may need to zero out
531 * a padding long to align with a 64bit remote */
537 /* you better not modify the bitmap while this is running,
538 * or its results will be stale */
539 static unsigned long bm_count_bits(struct drbd_bitmap *b)
541 unsigned long *p_addr;
542 unsigned long bits = 0;
543 unsigned long mask = (1UL << (b->bm_bits & BITS_PER_LONG_MASK)) -1;
544 int idx, i, last_word;
546 /* all but last page */
547 for (idx = 0; idx < b->bm_number_of_pages - 1; idx++) {
548 p_addr = __bm_map_pidx(b, idx);
549 for (i = 0; i < LWPP; i++)
550 bits += hweight_long(p_addr[i]);
554 /* last (or only) page */
555 last_word = ((b->bm_bits - 1) & BITS_PER_PAGE_MASK) >> LN2_BPL;
556 p_addr = __bm_map_pidx(b, idx);
557 for (i = 0; i < last_word; i++)
558 bits += hweight_long(p_addr[i]);
559 p_addr[last_word] &= cpu_to_lel(mask);
560 bits += hweight_long(p_addr[last_word]);
561 /* 32bit arch, may have an unused padding long */
562 if (BITS_PER_LONG == 32 && (last_word & 1) == 0)
563 p_addr[last_word+1] = 0;
568 /* offset and len in long words.*/
569 static void bm_memset(struct drbd_bitmap *b, size_t offset, int c, size_t len)
571 unsigned long *p_addr, *bm;
577 if (end > b->bm_words) {
578 printk(KERN_ALERT "drbd: bm_memset end > bm_words\n");
582 while (offset < end) {
583 do_now = min_t(size_t, ALIGN(offset + 1, LWPP), end) - offset;
584 idx = bm_word_to_page_idx(b, offset);
585 p_addr = bm_map_pidx(b, idx);
586 bm = p_addr + MLPP(offset);
587 if (bm+do_now > p_addr + LWPP) {
588 printk(KERN_ALERT "drbd: BUG BUG BUG! p_addr:%p bm:%p do_now:%d\n",
589 p_addr, bm, (int)do_now);
591 memset(bm, c, do_now * sizeof(long));
593 bm_set_page_need_writeout(b->bm_pages[idx]);
599 * make sure the bitmap has enough room for the attached storage,
600 * if necessary, resize.
601 * called whenever we may have changed the device size.
602 * returns -ENOMEM if we could not allocate enough memory, 0 on success.
603 * In case this is actually a resize, we copy the old bitmap into the new one.
604 * Otherwise, the bitmap is initialized to all bits set.
606 int drbd_bm_resize(struct drbd_conf *mdev, sector_t capacity, int set_new_bits)
608 struct drbd_bitmap *b = mdev->bitmap;
609 unsigned long bits, words, owords, obits;
610 unsigned long want, have, onpages; /* number of pages */
611 struct page **npages, **opages = NULL;
612 int err = 0, growing;
613 int opages_vmalloced;
615 ERR_IF(!b) return -ENOMEM;
617 drbd_bm_lock(mdev, "resize", BM_LOCKED_MASK);
619 dev_info(DEV, "drbd_bm_resize called with capacity == %llu\n",
620 (unsigned long long)capacity);
622 if (capacity == b->bm_dev_capacity)
625 opages_vmalloced = (BM_P_VMALLOCED & b->bm_flags);
628 spin_lock_irq(&b->bm_lock);
629 opages = b->bm_pages;
630 onpages = b->bm_number_of_pages;
631 owords = b->bm_words;
633 b->bm_number_of_pages =
637 b->bm_dev_capacity = 0;
638 spin_unlock_irq(&b->bm_lock);
639 bm_free_pages(opages, onpages);
640 bm_vk_free(opages, opages_vmalloced);
643 bits = BM_SECT_TO_BIT(ALIGN(capacity, BM_SECT_PER_BIT));
646 words = ALIGN(bits,BITS_PER_LONG) >> LN2_BPL;
647 a 32bit host could present the wrong number of words
650 words = ALIGN(bits, 64) >> LN2_BPL;
652 if (get_ldev(mdev)) {
653 u64 bits_on_disk = ((u64)mdev->ldev->md.md_size_sect-MD_BM_OFFSET) << 12;
655 if (bits > bits_on_disk) {
656 dev_info(DEV, "bits = %lu\n", bits);
657 dev_info(DEV, "bits_on_disk = %llu\n", bits_on_disk);
663 want = ALIGN(words*sizeof(long), PAGE_SIZE) >> PAGE_SHIFT;
664 have = b->bm_number_of_pages;
666 D_ASSERT(b->bm_pages != NULL);
667 npages = b->bm_pages;
669 if (drbd_insert_fault(mdev, DRBD_FAULT_BM_ALLOC))
672 npages = bm_realloc_pages(b, want);
680 spin_lock_irq(&b->bm_lock);
681 opages = b->bm_pages;
682 owords = b->bm_words;
685 growing = bits > obits;
686 if (opages && growing && set_new_bits)
689 b->bm_pages = npages;
690 b->bm_number_of_pages = want;
693 b->bm_dev_capacity = capacity;
697 bm_memset(b, owords, 0xff, words-owords);
698 b->bm_set += bits - obits;
700 bm_memset(b, owords, 0x00, words-owords);
705 /* implicit: (opages != NULL) && (opages != npages) */
706 bm_free_pages(opages + want, have - want);
709 (void)bm_clear_surplus(b);
711 spin_unlock_irq(&b->bm_lock);
712 if (opages != npages)
713 bm_vk_free(opages, opages_vmalloced);
715 b->bm_set = bm_count_bits(b);
716 dev_info(DEV, "resync bitmap: bits=%lu words=%lu pages=%lu\n", bits, words, want);
719 drbd_bm_unlock(mdev);
724 * if not protected by other means, return value may be out of date when
725 * leaving this function...
726 * we still need to lock it, since it is important that this returns
727 * bm_set == 0 precisely.
729 * maybe bm_set should be atomic_t ?
731 unsigned long _drbd_bm_total_weight(struct drbd_conf *mdev)
733 struct drbd_bitmap *b = mdev->bitmap;
738 ERR_IF(!b->bm_pages) return 0;
740 spin_lock_irqsave(&b->bm_lock, flags);
742 spin_unlock_irqrestore(&b->bm_lock, flags);
747 unsigned long drbd_bm_total_weight(struct drbd_conf *mdev)
750 /* if I don't have a disk, I don't know about out-of-sync status */
751 if (!get_ldev_if_state(mdev, D_NEGOTIATING))
753 s = _drbd_bm_total_weight(mdev);
758 size_t drbd_bm_words(struct drbd_conf *mdev)
760 struct drbd_bitmap *b = mdev->bitmap;
762 ERR_IF(!b->bm_pages) return 0;
767 unsigned long drbd_bm_bits(struct drbd_conf *mdev)
769 struct drbd_bitmap *b = mdev->bitmap;
775 /* merge number words from buffer into the bitmap starting at offset.
776 * buffer[i] is expected to be little endian unsigned long.
777 * bitmap must be locked by drbd_bm_lock.
778 * currently only used from receive_bitmap.
780 void drbd_bm_merge_lel(struct drbd_conf *mdev, size_t offset, size_t number,
781 unsigned long *buffer)
783 struct drbd_bitmap *b = mdev->bitmap;
784 unsigned long *p_addr, *bm;
785 unsigned long word, bits;
789 end = offset + number;
792 ERR_IF(!b->bm_pages) return;
795 WARN_ON(offset >= b->bm_words);
796 WARN_ON(end > b->bm_words);
798 spin_lock_irq(&b->bm_lock);
799 while (offset < end) {
800 do_now = min_t(size_t, ALIGN(offset+1, LWPP), end) - offset;
801 idx = bm_word_to_page_idx(b, offset);
802 p_addr = bm_map_pidx(b, idx);
803 bm = p_addr + MLPP(offset);
806 bits = hweight_long(*bm);
807 word = *bm | *buffer++;
809 b->bm_set += hweight_long(word) - bits;
812 bm_set_page_need_writeout(b->bm_pages[idx]);
814 /* with 32bit <-> 64bit cross-platform connect
815 * this is only correct for current usage,
816 * where we _know_ that we are 64 bit aligned,
817 * and know that this function is used in this way, too...
819 if (end == b->bm_words)
820 b->bm_set -= bm_clear_surplus(b);
821 spin_unlock_irq(&b->bm_lock);
824 /* copy number words from the bitmap starting at offset into the buffer.
825 * buffer[i] will be little endian unsigned long.
827 void drbd_bm_get_lel(struct drbd_conf *mdev, size_t offset, size_t number,
828 unsigned long *buffer)
830 struct drbd_bitmap *b = mdev->bitmap;
831 unsigned long *p_addr, *bm;
834 end = offset + number;
837 ERR_IF(!b->bm_pages) return;
839 spin_lock_irq(&b->bm_lock);
840 if ((offset >= b->bm_words) ||
841 (end > b->bm_words) ||
843 dev_err(DEV, "offset=%lu number=%lu bm_words=%lu\n",
844 (unsigned long) offset,
845 (unsigned long) number,
846 (unsigned long) b->bm_words);
848 while (offset < end) {
849 do_now = min_t(size_t, ALIGN(offset+1, LWPP), end) - offset;
850 p_addr = bm_map_pidx(b, bm_word_to_page_idx(b, offset));
851 bm = p_addr + MLPP(offset);
858 spin_unlock_irq(&b->bm_lock);
861 /* set all bits in the bitmap */
862 void drbd_bm_set_all(struct drbd_conf *mdev)
864 struct drbd_bitmap *b = mdev->bitmap;
866 ERR_IF(!b->bm_pages) return;
868 spin_lock_irq(&b->bm_lock);
869 bm_memset(b, 0, 0xff, b->bm_words);
870 (void)bm_clear_surplus(b);
871 b->bm_set = b->bm_bits;
872 spin_unlock_irq(&b->bm_lock);
875 /* clear all bits in the bitmap */
876 void drbd_bm_clear_all(struct drbd_conf *mdev)
878 struct drbd_bitmap *b = mdev->bitmap;
880 ERR_IF(!b->bm_pages) return;
882 spin_lock_irq(&b->bm_lock);
883 bm_memset(b, 0, 0, b->bm_words);
885 spin_unlock_irq(&b->bm_lock);
889 struct drbd_conf *mdev;
893 #define BM_AIO_COPY_PAGES 1
894 #define BM_WRITE_ALL_PAGES 2
899 static void bm_aio_ctx_destroy(struct kref *kref)
901 struct bm_aio_ctx *ctx = container_of(kref, struct bm_aio_ctx, kref);
907 /* bv_page may be a copy, or may be the original */
908 static void bm_async_io_complete(struct bio *bio, int error)
910 struct bm_aio_ctx *ctx = bio->bi_private;
911 struct drbd_conf *mdev = ctx->mdev;
912 struct drbd_bitmap *b = mdev->bitmap;
913 unsigned int idx = bm_page_to_idx(bio->bi_io_vec[0].bv_page);
914 int uptodate = bio_flagged(bio, BIO_UPTODATE);
917 /* strange behavior of some lower level drivers...
918 * fail the request by clearing the uptodate flag,
919 * but do not return any error?!
920 * do we want to WARN() on this? */
921 if (!error && !uptodate)
924 if ((ctx->flags & BM_AIO_COPY_PAGES) == 0 &&
925 !bm_test_page_unchanged(b->bm_pages[idx]))
926 dev_warn(DEV, "bitmap page idx %u changed during IO!\n", idx);
929 /* ctx error will hold the completed-last non-zero error code,
930 * in case error codes differ. */
932 bm_set_page_io_err(b->bm_pages[idx]);
933 /* Not identical to on disk version of it.
934 * Is BM_PAGE_IO_ERROR enough? */
935 if (__ratelimit(&drbd_ratelimit_state))
936 dev_err(DEV, "IO ERROR %d on bitmap page idx %u\n",
939 bm_clear_page_io_err(b->bm_pages[idx]);
940 dynamic_dev_dbg(DEV, "bitmap page idx %u completed\n", idx);
943 bm_page_unlock_io(mdev, idx);
945 if (ctx->flags & BM_AIO_COPY_PAGES)
946 mempool_free(bio->bi_io_vec[0].bv_page, drbd_md_io_page_pool);
950 if (atomic_dec_and_test(&ctx->in_flight)) {
952 wake_up(&mdev->misc_wait);
953 kref_put(&ctx->kref, &bm_aio_ctx_destroy);
957 static void bm_page_io_async(struct bm_aio_ctx *ctx, int page_nr, int rw) __must_hold(local)
959 struct bio *bio = bio_alloc_drbd(GFP_NOIO);
960 struct drbd_conf *mdev = ctx->mdev;
961 struct drbd_bitmap *b = mdev->bitmap;
965 sector_t on_disk_sector =
966 mdev->ldev->md.md_offset + mdev->ldev->md.bm_offset;
967 on_disk_sector += ((sector_t)page_nr) << (PAGE_SHIFT-9);
969 /* this might happen with very small
970 * flexible external meta data device,
971 * or with PAGE_SIZE > 4k */
972 len = min_t(unsigned int, PAGE_SIZE,
973 (drbd_md_last_sector(mdev->ldev) - on_disk_sector + 1)<<9);
975 /* serialize IO on this page */
976 bm_page_lock_io(mdev, page_nr);
977 /* before memcpy and submit,
978 * so it can be redirtied any time */
979 bm_set_page_unchanged(b->bm_pages[page_nr]);
981 if (ctx->flags & BM_AIO_COPY_PAGES) {
983 page = mempool_alloc(drbd_md_io_page_pool, __GFP_HIGHMEM|__GFP_WAIT);
984 dest = kmap_atomic(page);
985 src = kmap_atomic(b->bm_pages[page_nr]);
986 memcpy(dest, src, PAGE_SIZE);
989 bm_store_page_idx(page, page_nr);
991 page = b->bm_pages[page_nr];
993 bio->bi_bdev = mdev->ldev->md_bdev;
994 bio->bi_sector = on_disk_sector;
995 /* bio_add_page of a single page to an empty bio will always succeed,
996 * according to api. Do we want to assert that? */
997 bio_add_page(bio, page, len, 0);
998 bio->bi_private = ctx;
999 bio->bi_end_io = bm_async_io_complete;
1001 if (drbd_insert_fault(mdev, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD)) {
1003 bio_endio(bio, -EIO);
1005 submit_bio(rw, bio);
1006 /* this should not count as user activity and cause the
1007 * resync to throttle -- see drbd_rs_should_slow_down(). */
1008 atomic_add(len >> 9, &mdev->rs_sect_ev);
1013 * bm_rw: read/write the whole bitmap from/to its on disk location.
1015 static int bm_rw(struct drbd_conf *mdev, int rw, unsigned flags, unsigned lazy_writeout_upper_idx) __must_hold(local)
1017 struct bm_aio_ctx *ctx;
1018 struct drbd_bitmap *b = mdev->bitmap;
1019 int num_pages, i, count = 0;
1025 * We are protected against bitmap disappearing/resizing by holding an
1026 * ldev reference (caller must have called get_ldev()).
1027 * For read/write, we are protected against changes to the bitmap by
1028 * the bitmap lock (see drbd_bitmap_io).
1029 * For lazy writeout, we don't care for ongoing changes to the bitmap,
1030 * as we submit copies of pages anyways.
1033 ctx = kmalloc(sizeof(struct bm_aio_ctx), GFP_NOIO);
1037 *ctx = (struct bm_aio_ctx) {
1039 .in_flight = ATOMIC_INIT(1),
1043 .kref = { ATOMIC_INIT(2) },
1046 if (!get_ldev_if_state(mdev, D_ATTACHING)) { /* put is in bm_aio_ctx_destroy() */
1047 dev_err(DEV, "ASSERT FAILED: get_ldev_if_state() == 1 in bm_rw()\n");
1053 WARN_ON(!(BM_LOCKED_MASK & b->bm_flags));
1055 num_pages = b->bm_number_of_pages;
1059 /* let the layers below us try to merge these bios... */
1060 for (i = 0; i < num_pages; i++) {
1061 /* ignore completely unchanged pages */
1062 if (lazy_writeout_upper_idx && i == lazy_writeout_upper_idx)
1065 if (!(flags & BM_WRITE_ALL_PAGES) &&
1066 bm_test_page_unchanged(b->bm_pages[i])) {
1067 dynamic_dev_dbg(DEV, "skipped bm write for idx %u\n", i);
1070 /* during lazy writeout,
1071 * ignore those pages not marked for lazy writeout. */
1072 if (lazy_writeout_upper_idx &&
1073 !bm_test_page_lazy_writeout(b->bm_pages[i])) {
1074 dynamic_dev_dbg(DEV, "skipped bm lazy write for idx %u\n", i);
1078 atomic_inc(&ctx->in_flight);
1079 bm_page_io_async(ctx, i, rw);
1085 * We initialize ctx->in_flight to one to make sure bm_async_io_complete
1086 * will not set ctx->done early, and decrement / test it here. If there
1087 * are still some bios in flight, we need to wait for them here.
1088 * If all IO is done already (or nothing had been submitted), there is
1089 * no need to wait. Still, we need to put the kref associated with the
1090 * "in_flight reached zero, all done" event.
1092 if (!atomic_dec_and_test(&ctx->in_flight))
1093 wait_until_done_or_force_detached(mdev, mdev->ldev, &ctx->done);
1095 kref_put(&ctx->kref, &bm_aio_ctx_destroy);
1097 dev_info(DEV, "bitmap %s of %u pages took %lu jiffies\n",
1098 rw == WRITE ? "WRITE" : "READ",
1099 count, jiffies - now);
1102 dev_alert(DEV, "we had at least one MD IO ERROR during bitmap IO\n");
1103 drbd_chk_io_error(mdev, 1, DRBD_META_IO_ERROR);
1104 err = -EIO; /* ctx->error ? */
1107 if (atomic_read(&ctx->in_flight))
1108 err = -EIO; /* Disk timeout/force-detach during IO... */
1112 drbd_md_flush(mdev);
1113 } else /* rw == READ */ {
1114 b->bm_set = bm_count_bits(b);
1115 dev_info(DEV, "recounting of set bits took additional %lu jiffies\n",
1120 dev_info(DEV, "%s (%lu bits) marked out-of-sync by on disk bit-map.\n",
1121 ppsize(ppb, now << (BM_BLOCK_SHIFT-10)), now);
1123 kref_put(&ctx->kref, &bm_aio_ctx_destroy);
1128 * drbd_bm_read() - Read the whole bitmap from its on disk location.
1129 * @mdev: DRBD device.
1131 int drbd_bm_read(struct drbd_conf *mdev) __must_hold(local)
1133 return bm_rw(mdev, READ, 0, 0);
1137 * drbd_bm_write() - Write the whole bitmap to its on disk location.
1138 * @mdev: DRBD device.
1140 * Will only write pages that have changed since last IO.
1142 int drbd_bm_write(struct drbd_conf *mdev) __must_hold(local)
1144 return bm_rw(mdev, WRITE, 0, 0);
1148 * drbd_bm_write_all() - Write the whole bitmap to its on disk location.
1149 * @mdev: DRBD device.
1151 * Will write all pages.
1153 int drbd_bm_write_all(struct drbd_conf *mdev) __must_hold(local)
1155 return bm_rw(mdev, WRITE, BM_WRITE_ALL_PAGES, 0);
1159 * drbd_bm_lazy_write_out() - Write bitmap pages 0 to @upper_idx-1, if they have changed.
1160 * @mdev: DRBD device.
1161 * @upper_idx: 0: write all changed pages; +ve: page index to stop scanning for changed pages
1163 int drbd_bm_write_lazy(struct drbd_conf *mdev, unsigned upper_idx) __must_hold(local)
1165 return bm_rw(mdev, WRITE, BM_AIO_COPY_PAGES, upper_idx);
1169 * drbd_bm_write_copy_pages() - Write the whole bitmap to its on disk location.
1170 * @mdev: DRBD device.
1172 * Will only write pages that have changed since last IO.
1173 * In contrast to drbd_bm_write(), this will copy the bitmap pages
1174 * to temporary writeout pages. It is intended to trigger a full write-out
1175 * while still allowing the bitmap to change, for example if a resync or online
1176 * verify is aborted due to a failed peer disk, while local IO continues, or
1177 * pending resync acks are still being processed.
1179 int drbd_bm_write_copy_pages(struct drbd_conf *mdev) __must_hold(local)
1181 return bm_rw(mdev, WRITE, BM_AIO_COPY_PAGES, 0);
1186 * drbd_bm_write_page: Writes a PAGE_SIZE aligned piece of bitmap
1187 * @mdev: DRBD device.
1188 * @idx: bitmap page index
1190 * We don't want to special case on logical_block_size of the backend device,
1191 * so we submit PAGE_SIZE aligned pieces.
1192 * Note that on "most" systems, PAGE_SIZE is 4k.
1194 * In case this becomes an issue on systems with larger PAGE_SIZE,
1195 * we may want to change this again to write 4k aligned 4k pieces.
1197 int drbd_bm_write_page(struct drbd_conf *mdev, unsigned int idx) __must_hold(local)
1199 struct bm_aio_ctx *ctx;
1202 if (bm_test_page_unchanged(mdev->bitmap->bm_pages[idx])) {
1203 dynamic_dev_dbg(DEV, "skipped bm page write for idx %u\n", idx);
1207 ctx = kmalloc(sizeof(struct bm_aio_ctx), GFP_NOIO);
1211 *ctx = (struct bm_aio_ctx) {
1213 .in_flight = ATOMIC_INIT(1),
1215 .flags = BM_AIO_COPY_PAGES,
1217 .kref = { ATOMIC_INIT(2) },
1220 if (!get_ldev_if_state(mdev, D_ATTACHING)) { /* put is in bm_aio_ctx_destroy() */
1221 dev_err(DEV, "ASSERT FAILED: get_ldev_if_state() == 1 in drbd_bm_write_page()\n");
1226 bm_page_io_async(ctx, idx, WRITE_SYNC);
1227 wait_until_done_or_force_detached(mdev, mdev->ldev, &ctx->done);
1230 drbd_chk_io_error(mdev, 1, DRBD_META_IO_ERROR);
1231 /* that causes us to detach, so the in memory bitmap will be
1232 * gone in a moment as well. */
1234 mdev->bm_writ_cnt++;
1235 err = atomic_read(&ctx->in_flight) ? -EIO : ctx->error;
1236 kref_put(&ctx->kref, &bm_aio_ctx_destroy);
1241 * find_first_bit returns int, we return unsigned long.
1242 * For this to work on 32bit arch with bitnumbers > (1<<32),
1243 * we'd need to return u64, and get a whole lot of other places
1244 * fixed where we still use unsigned long.
1246 * this returns a bit number, NOT a sector!
1248 static unsigned long __bm_find_next(struct drbd_conf *mdev, unsigned long bm_fo,
1249 const int find_zero_bit)
1251 struct drbd_bitmap *b = mdev->bitmap;
1252 unsigned long *p_addr;
1253 unsigned long bit_offset;
1257 if (bm_fo > b->bm_bits) {
1258 dev_err(DEV, "bm_fo=%lu bm_bits=%lu\n", bm_fo, b->bm_bits);
1259 bm_fo = DRBD_END_OF_BITMAP;
1261 while (bm_fo < b->bm_bits) {
1262 /* bit offset of the first bit in the page */
1263 bit_offset = bm_fo & ~BITS_PER_PAGE_MASK;
1264 p_addr = __bm_map_pidx(b, bm_bit_to_page_idx(b, bm_fo));
1267 i = find_next_zero_bit_le(p_addr,
1268 PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK);
1270 i = find_next_bit_le(p_addr,
1271 PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK);
1274 if (i < PAGE_SIZE*8) {
1275 bm_fo = bit_offset + i;
1276 if (bm_fo >= b->bm_bits)
1280 bm_fo = bit_offset + PAGE_SIZE*8;
1282 bm_fo = DRBD_END_OF_BITMAP;
1288 static unsigned long bm_find_next(struct drbd_conf *mdev,
1289 unsigned long bm_fo, const int find_zero_bit)
1291 struct drbd_bitmap *b = mdev->bitmap;
1292 unsigned long i = DRBD_END_OF_BITMAP;
1294 ERR_IF(!b) return i;
1295 ERR_IF(!b->bm_pages) return i;
1297 spin_lock_irq(&b->bm_lock);
1298 if (BM_DONT_TEST & b->bm_flags)
1299 bm_print_lock_info(mdev);
1301 i = __bm_find_next(mdev, bm_fo, find_zero_bit);
1303 spin_unlock_irq(&b->bm_lock);
1307 unsigned long drbd_bm_find_next(struct drbd_conf *mdev, unsigned long bm_fo)
1309 return bm_find_next(mdev, bm_fo, 0);
1313 /* not yet needed for anything. */
1314 unsigned long drbd_bm_find_next_zero(struct drbd_conf *mdev, unsigned long bm_fo)
1316 return bm_find_next(mdev, bm_fo, 1);
1320 /* does not spin_lock_irqsave.
1321 * you must take drbd_bm_lock() first */
1322 unsigned long _drbd_bm_find_next(struct drbd_conf *mdev, unsigned long bm_fo)
1324 /* WARN_ON(!(BM_DONT_SET & mdev->b->bm_flags)); */
1325 return __bm_find_next(mdev, bm_fo, 0);
1328 unsigned long _drbd_bm_find_next_zero(struct drbd_conf *mdev, unsigned long bm_fo)
1330 /* WARN_ON(!(BM_DONT_SET & mdev->b->bm_flags)); */
1331 return __bm_find_next(mdev, bm_fo, 1);
1334 /* returns number of bits actually changed.
1335 * for val != 0, we change 0 -> 1, return code positive
1336 * for val == 0, we change 1 -> 0, return code negative
1337 * wants bitnr, not sector.
1338 * expected to be called for only a few bits (e - s about BITS_PER_LONG).
1339 * Must hold bitmap lock already. */
1340 static int __bm_change_bits_to(struct drbd_conf *mdev, const unsigned long s,
1341 unsigned long e, int val)
1343 struct drbd_bitmap *b = mdev->bitmap;
1344 unsigned long *p_addr = NULL;
1345 unsigned long bitnr;
1346 unsigned int last_page_nr = -1U;
1348 int changed_total = 0;
1350 if (e >= b->bm_bits) {
1351 dev_err(DEV, "ASSERT FAILED: bit_s=%lu bit_e=%lu bm_bits=%lu\n",
1353 e = b->bm_bits ? b->bm_bits -1 : 0;
1355 for (bitnr = s; bitnr <= e; bitnr++) {
1356 unsigned int page_nr = bm_bit_to_page_idx(b, bitnr);
1357 if (page_nr != last_page_nr) {
1361 bm_set_page_lazy_writeout(b->bm_pages[last_page_nr]);
1363 bm_set_page_need_writeout(b->bm_pages[last_page_nr]);
1366 p_addr = __bm_map_pidx(b, page_nr);
1367 last_page_nr = page_nr;
1370 c += (0 == __test_and_set_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr));
1372 c -= (0 != __test_and_clear_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr));
1377 bm_set_page_lazy_writeout(b->bm_pages[last_page_nr]);
1379 bm_set_page_need_writeout(b->bm_pages[last_page_nr]);
1381 b->bm_set += changed_total;
1382 return changed_total;
1385 /* returns number of bits actually changed.
1386 * for val != 0, we change 0 -> 1, return code positive
1387 * for val == 0, we change 1 -> 0, return code negative
1388 * wants bitnr, not sector */
1389 static int bm_change_bits_to(struct drbd_conf *mdev, const unsigned long s,
1390 const unsigned long e, int val)
1392 unsigned long flags;
1393 struct drbd_bitmap *b = mdev->bitmap;
1396 ERR_IF(!b) return 1;
1397 ERR_IF(!b->bm_pages) return 0;
1399 spin_lock_irqsave(&b->bm_lock, flags);
1400 if ((val ? BM_DONT_SET : BM_DONT_CLEAR) & b->bm_flags)
1401 bm_print_lock_info(mdev);
1403 c = __bm_change_bits_to(mdev, s, e, val);
1405 spin_unlock_irqrestore(&b->bm_lock, flags);
1409 /* returns number of bits changed 0 -> 1 */
1410 int drbd_bm_set_bits(struct drbd_conf *mdev, const unsigned long s, const unsigned long e)
1412 return bm_change_bits_to(mdev, s, e, 1);
1415 /* returns number of bits changed 1 -> 0 */
1416 int drbd_bm_clear_bits(struct drbd_conf *mdev, const unsigned long s, const unsigned long e)
1418 return -bm_change_bits_to(mdev, s, e, 0);
1421 /* sets all bits in full words,
1422 * from first_word up to, but not including, last_word */
1423 static inline void bm_set_full_words_within_one_page(struct drbd_bitmap *b,
1424 int page_nr, int first_word, int last_word)
1428 unsigned long *paddr = kmap_atomic(b->bm_pages[page_nr]);
1429 for (i = first_word; i < last_word; i++) {
1430 bits = hweight_long(paddr[i]);
1432 b->bm_set += BITS_PER_LONG - bits;
1434 kunmap_atomic(paddr);
1437 /* Same thing as drbd_bm_set_bits,
1438 * but more efficient for a large bit range.
1439 * You must first drbd_bm_lock().
1440 * Can be called to set the whole bitmap in one go.
1441 * Sets bits from s to e _inclusive_. */
1442 void _drbd_bm_set_bits(struct drbd_conf *mdev, const unsigned long s, const unsigned long e)
1444 /* First set_bit from the first bit (s)
1445 * up to the next long boundary (sl),
1446 * then assign full words up to the last long boundary (el),
1447 * then set_bit up to and including the last bit (e).
1449 * Do not use memset, because we must account for changes,
1450 * so we need to loop over the words with hweight() anyways.
1452 struct drbd_bitmap *b = mdev->bitmap;
1453 unsigned long sl = ALIGN(s,BITS_PER_LONG);
1454 unsigned long el = (e+1) & ~((unsigned long)BITS_PER_LONG-1);
1461 if (e - s <= 3*BITS_PER_LONG) {
1462 /* don't bother; el and sl may even be wrong. */
1463 spin_lock_irq(&b->bm_lock);
1464 __bm_change_bits_to(mdev, s, e, 1);
1465 spin_unlock_irq(&b->bm_lock);
1469 /* difference is large enough that we can trust sl and el */
1471 spin_lock_irq(&b->bm_lock);
1473 /* bits filling the current long */
1475 __bm_change_bits_to(mdev, s, sl-1, 1);
1477 first_page = sl >> (3 + PAGE_SHIFT);
1478 last_page = el >> (3 + PAGE_SHIFT);
1480 /* MLPP: modulo longs per page */
1481 /* LWPP: long words per page */
1482 first_word = MLPP(sl >> LN2_BPL);
1485 /* first and full pages, unless first page == last page */
1486 for (page_nr = first_page; page_nr < last_page; page_nr++) {
1487 bm_set_full_words_within_one_page(mdev->bitmap, page_nr, first_word, last_word);
1488 spin_unlock_irq(&b->bm_lock);
1491 spin_lock_irq(&b->bm_lock);
1493 /* last page (respectively only page, for first page == last page) */
1494 last_word = MLPP(el >> LN2_BPL);
1496 /* consider bitmap->bm_bits = 32768, bitmap->bm_number_of_pages = 1. (or multiples).
1497 * ==> e = 32767, el = 32768, last_page = 2,
1498 * and now last_word = 0.
1499 * We do not want to touch last_page in this case,
1500 * as we did not allocate it, it is not present in bitmap->bm_pages.
1503 bm_set_full_words_within_one_page(mdev->bitmap, last_page, first_word, last_word);
1505 /* possibly trailing bits.
1506 * example: (e & 63) == 63, el will be e+1.
1507 * if that even was the very last bit,
1508 * it would trigger an assert in __bm_change_bits_to()
1511 __bm_change_bits_to(mdev, el, e, 1);
1512 spin_unlock_irq(&b->bm_lock);
1515 /* returns bit state
1516 * wants bitnr, NOT sector.
1517 * inherently racy... area needs to be locked by means of {al,rs}_lru
1520 * -1 ... first out of bounds access, stop testing for bits!
1522 int drbd_bm_test_bit(struct drbd_conf *mdev, const unsigned long bitnr)
1524 unsigned long flags;
1525 struct drbd_bitmap *b = mdev->bitmap;
1526 unsigned long *p_addr;
1529 ERR_IF(!b) return 0;
1530 ERR_IF(!b->bm_pages) return 0;
1532 spin_lock_irqsave(&b->bm_lock, flags);
1533 if (BM_DONT_TEST & b->bm_flags)
1534 bm_print_lock_info(mdev);
1535 if (bitnr < b->bm_bits) {
1536 p_addr = bm_map_pidx(b, bm_bit_to_page_idx(b, bitnr));
1537 i = test_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr) ? 1 : 0;
1539 } else if (bitnr == b->bm_bits) {
1541 } else { /* (bitnr > b->bm_bits) */
1542 dev_err(DEV, "bitnr=%lu > bm_bits=%lu\n", bitnr, b->bm_bits);
1546 spin_unlock_irqrestore(&b->bm_lock, flags);
1550 /* returns number of bits set in the range [s, e] */
1551 int drbd_bm_count_bits(struct drbd_conf *mdev, const unsigned long s, const unsigned long e)
1553 unsigned long flags;
1554 struct drbd_bitmap *b = mdev->bitmap;
1555 unsigned long *p_addr = NULL;
1556 unsigned long bitnr;
1557 unsigned int page_nr = -1U;
1560 /* If this is called without a bitmap, that is a bug. But just to be
1561 * robust in case we screwed up elsewhere, in that case pretend there
1562 * was one dirty bit in the requested area, so we won't try to do a
1563 * local read there (no bitmap probably implies no disk) */
1564 ERR_IF(!b) return 1;
1565 ERR_IF(!b->bm_pages) return 1;
1567 spin_lock_irqsave(&b->bm_lock, flags);
1568 if (BM_DONT_TEST & b->bm_flags)
1569 bm_print_lock_info(mdev);
1570 for (bitnr = s; bitnr <= e; bitnr++) {
1571 unsigned int idx = bm_bit_to_page_idx(b, bitnr);
1572 if (page_nr != idx) {
1576 p_addr = bm_map_pidx(b, idx);
1578 ERR_IF (bitnr >= b->bm_bits) {
1579 dev_err(DEV, "bitnr=%lu bm_bits=%lu\n", bitnr, b->bm_bits);
1581 c += (0 != test_bit_le(bitnr - (page_nr << (PAGE_SHIFT+3)), p_addr));
1586 spin_unlock_irqrestore(&b->bm_lock, flags);
1591 /* inherently racy...
1592 * return value may be already out-of-date when this function returns.
1593 * but the general usage is that this is only use during a cstate when bits are
1594 * only cleared, not set, and typically only care for the case when the return
1595 * value is zero, or we already "locked" this "bitmap extent" by other means.
1597 * enr is bm-extent number, since we chose to name one sector (512 bytes)
1598 * worth of the bitmap a "bitmap extent".
1601 * I think since we use it like a reference count, we should use the real
1602 * reference count of some bitmap extent element from some lru instead...
1605 int drbd_bm_e_weight(struct drbd_conf *mdev, unsigned long enr)
1607 struct drbd_bitmap *b = mdev->bitmap;
1609 unsigned long flags;
1610 unsigned long *p_addr, *bm;
1612 ERR_IF(!b) return 0;
1613 ERR_IF(!b->bm_pages) return 0;
1615 spin_lock_irqsave(&b->bm_lock, flags);
1616 if (BM_DONT_TEST & b->bm_flags)
1617 bm_print_lock_info(mdev);
1620 e = min((size_t)S2W(enr+1), b->bm_words);
1622 if (s < b->bm_words) {
1624 p_addr = bm_map_pidx(b, bm_word_to_page_idx(b, s));
1625 bm = p_addr + MLPP(s);
1627 count += hweight_long(*bm++);
1630 dev_err(DEV, "start offset (%d) too large in drbd_bm_e_weight\n", s);
1632 spin_unlock_irqrestore(&b->bm_lock, flags);
1636 /* Set all bits covered by the AL-extent al_enr.
1637 * Returns number of bits changed. */
1638 unsigned long drbd_bm_ALe_set_all(struct drbd_conf *mdev, unsigned long al_enr)
1640 struct drbd_bitmap *b = mdev->bitmap;
1641 unsigned long *p_addr, *bm;
1642 unsigned long weight;
1644 int count, i, do_now;
1645 ERR_IF(!b) return 0;
1646 ERR_IF(!b->bm_pages) return 0;
1648 spin_lock_irq(&b->bm_lock);
1649 if (BM_DONT_SET & b->bm_flags)
1650 bm_print_lock_info(mdev);
1653 s = al_enr * BM_WORDS_PER_AL_EXT;
1654 e = min_t(size_t, s + BM_WORDS_PER_AL_EXT, b->bm_words);
1655 /* assert that s and e are on the same page */
1656 D_ASSERT((e-1) >> (PAGE_SHIFT - LN2_BPL + 3)
1657 == s >> (PAGE_SHIFT - LN2_BPL + 3));
1659 if (s < b->bm_words) {
1661 p_addr = bm_map_pidx(b, bm_word_to_page_idx(b, s));
1662 bm = p_addr + MLPP(s);
1664 count += hweight_long(*bm);
1669 b->bm_set += do_now*BITS_PER_LONG - count;
1670 if (e == b->bm_words)
1671 b->bm_set -= bm_clear_surplus(b);
1673 dev_err(DEV, "start offset (%lu) too large in drbd_bm_ALe_set_all\n", s);
1675 weight = b->bm_set - weight;
1676 spin_unlock_irq(&b->bm_lock);