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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27 #include <linux/bitmap.h>
28 #include <linux/vmalloc.h>
29 #include <linux/string.h>
30 #include <linux/drbd.h>
31 #include <linux/slab.h>
32 #include <linux/highmem.h>
37 /* OPAQUE outside this file!
38 * interface defined in drbd_int.h
41 * function name drbd_bm_... => used elsewhere, "public".
42 * function name bm_... => internal to implementation, "private".
48 * We want to support >= peta byte of backend storage, while for now still using
49 * a granularity of one bit per 4KiB of storage.
50 * 1 << 50 bytes backend storage (1 PiB)
51 * 1 << (50 - 12) bits needed
52 * 38 --> we need u64 to index and count bits
53 * 1 << (38 - 3) bitmap bytes needed
54 * 35 --> we still need u64 to index and count bytes
55 * (that's 32 GiB of bitmap for 1 PiB storage)
56 * 1 << (35 - 2) 32bit longs needed
57 * 33 --> we'd even need u64 to index and count 32bit long words.
58 * 1 << (35 - 3) 64bit longs needed
59 * 32 --> we could get away with a 32bit unsigned int to index and count
60 * 64bit long words, but I rather stay with unsigned long for now.
61 * We probably should neither count nor point to bytes or long words
62 * directly, but either by bitnumber, or by page index and offset.
64 * 22 --> we need that much 4KiB pages of bitmap.
65 * 1 << (22 + 3) --> on a 64bit arch,
66 * we need 32 MiB to store the array of page pointers.
68 * Because I'm lazy, and because the resulting patch was too large, too ugly
69 * and still incomplete, on 32bit we still "only" support 16 TiB (minus some),
70 * (1 << 32) bits * 4k storage.
73 * bitmap storage and IO:
74 * Bitmap is stored little endian on disk, and is kept little endian in
75 * core memory. Currently we still hold the full bitmap in core as long
76 * as we are "attached" to a local disk, which at 32 GiB for 1PiB storage
79 * We plan to reduce the amount of in-core bitmap pages by paging them in
80 * and out against their on-disk location as necessary, but need to make
81 * sure we don't cause too much meta data IO, and must not deadlock in
82 * tight memory situations. This needs some more work.
87 * Access to the *bm_pages is protected by bm_lock.
88 * It is safe to read the other members within the lock.
90 * drbd_bm_set_bits is called from bio_endio callbacks,
91 * We may be called with irq already disabled,
92 * so we need spin_lock_irqsave().
93 * And we need the kmap_atomic.
96 struct page **bm_pages;
99 /* see LIMITATIONS: above */
101 unsigned long bm_set; /* nr of set bits; THINK maybe atomic_t? */
102 unsigned long bm_bits;
104 size_t bm_number_of_pages;
105 sector_t bm_dev_capacity;
106 struct mutex bm_change; /* serializes resize operations */
108 wait_queue_head_t bm_io_wait; /* used to serialize IO of single pages */
110 enum bm_flag bm_flags;
112 /* debugging aid, in case we are still racy somewhere */
114 struct task_struct *bm_task;
117 #define bm_print_lock_info(m) __bm_print_lock_info(m, __func__)
118 static void __bm_print_lock_info(struct drbd_device *device, const char *func)
120 struct drbd_bitmap *b = device->bitmap;
121 if (!__ratelimit(&drbd_ratelimit_state))
123 drbd_err(device, "FIXME %s[%d] in %s, bitmap locked for '%s' by %s[%d]\n",
124 current->comm, task_pid_nr(current),
125 func, b->bm_why ?: "?",
126 b->bm_task->comm, task_pid_nr(b->bm_task));
129 void drbd_bm_lock(struct drbd_device *device, char *why, enum bm_flag flags)
131 struct drbd_bitmap *b = device->bitmap;
135 drbd_err(device, "FIXME no bitmap in drbd_bm_lock!?\n");
139 trylock_failed = !mutex_trylock(&b->bm_change);
141 if (trylock_failed) {
142 drbd_warn(device, "%s[%d] going to '%s' but bitmap already locked for '%s' by %s[%d]\n",
143 current->comm, task_pid_nr(current),
144 why, b->bm_why ?: "?",
145 b->bm_task->comm, task_pid_nr(b->bm_task));
146 mutex_lock(&b->bm_change);
148 if (BM_LOCKED_MASK & b->bm_flags)
149 drbd_err(device, "FIXME bitmap already locked in bm_lock\n");
150 b->bm_flags |= flags & BM_LOCKED_MASK;
153 b->bm_task = current;
156 void drbd_bm_unlock(struct drbd_device *device)
158 struct drbd_bitmap *b = device->bitmap;
160 drbd_err(device, "FIXME no bitmap in drbd_bm_unlock!?\n");
164 if (!(BM_LOCKED_MASK & device->bitmap->bm_flags))
165 drbd_err(device, "FIXME bitmap not locked in bm_unlock\n");
167 b->bm_flags &= ~BM_LOCKED_MASK;
170 mutex_unlock(&b->bm_change);
173 /* we store some "meta" info about our pages in page->private */
174 /* at a granularity of 4k storage per bitmap bit:
175 * one peta byte storage: 1<<50 byte, 1<<38 * 4k storage blocks
177 * 1<<23 4k bitmap pages.
178 * Use 24 bits as page index, covers 2 peta byte storage
179 * at a granularity of 4k per bit.
180 * Used to report the failed page idx on io error from the endio handlers.
182 #define BM_PAGE_IDX_MASK ((1UL<<24)-1)
183 /* this page is currently read in, or written back */
184 #define BM_PAGE_IO_LOCK 31
185 /* if there has been an IO error for this page */
186 #define BM_PAGE_IO_ERROR 30
187 /* this is to be able to intelligently skip disk IO,
188 * set if bits have been set since last IO. */
189 #define BM_PAGE_NEED_WRITEOUT 29
190 /* to mark for lazy writeout once syncer cleared all clearable bits,
191 * we if bits have been cleared since last IO. */
192 #define BM_PAGE_LAZY_WRITEOUT 28
193 /* pages marked with this "HINT" will be considered for writeout
194 * on activity log transactions */
195 #define BM_PAGE_HINT_WRITEOUT 27
197 /* store_page_idx uses non-atomic assignment. It is only used directly after
198 * allocating the page. All other bm_set_page_* and bm_clear_page_* need to
199 * use atomic bit manipulation, as set_out_of_sync (and therefore bitmap
200 * changes) may happen from various contexts, and wait_on_bit/wake_up_bit
201 * requires it all to be atomic as well. */
202 static void bm_store_page_idx(struct page *page, unsigned long idx)
204 BUG_ON(0 != (idx & ~BM_PAGE_IDX_MASK));
205 set_page_private(page, idx);
208 static unsigned long bm_page_to_idx(struct page *page)
210 return page_private(page) & BM_PAGE_IDX_MASK;
213 /* As is very unlikely that the same page is under IO from more than one
214 * context, we can get away with a bit per page and one wait queue per bitmap.
216 static void bm_page_lock_io(struct drbd_device *device, int page_nr)
218 struct drbd_bitmap *b = device->bitmap;
219 void *addr = &page_private(b->bm_pages[page_nr]);
220 wait_event(b->bm_io_wait, !test_and_set_bit(BM_PAGE_IO_LOCK, addr));
223 static void bm_page_unlock_io(struct drbd_device *device, int page_nr)
225 struct drbd_bitmap *b = device->bitmap;
226 void *addr = &page_private(b->bm_pages[page_nr]);
227 clear_bit_unlock(BM_PAGE_IO_LOCK, addr);
228 wake_up(&device->bitmap->bm_io_wait);
231 /* set _before_ submit_io, so it may be reset due to being changed
232 * while this page is in flight... will get submitted later again */
233 static void bm_set_page_unchanged(struct page *page)
236 clear_bit(BM_PAGE_NEED_WRITEOUT, &page_private(page));
237 clear_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page));
240 static void bm_set_page_need_writeout(struct page *page)
242 set_bit(BM_PAGE_NEED_WRITEOUT, &page_private(page));
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
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.
254 void drbd_bm_mark_for_writeout(struct drbd_device *device, int page_nr)
257 if (page_nr >= device->bitmap->bm_number_of_pages) {
258 drbd_warn(device, "BAD: page_nr: %u, number_of_pages: %u\n",
259 page_nr, (int)device->bitmap->bm_number_of_pages);
262 page = device->bitmap->bm_pages[page_nr];
263 set_bit(BM_PAGE_HINT_WRITEOUT, &page_private(page));
266 static int bm_test_page_unchanged(struct page *page)
268 volatile const unsigned long *addr = &page_private(page);
269 return (*addr & ((1UL<<BM_PAGE_NEED_WRITEOUT)|(1UL<<BM_PAGE_LAZY_WRITEOUT))) == 0;
272 static void bm_set_page_io_err(struct page *page)
274 set_bit(BM_PAGE_IO_ERROR, &page_private(page));
277 static void bm_clear_page_io_err(struct page *page)
279 clear_bit(BM_PAGE_IO_ERROR, &page_private(page));
282 static void bm_set_page_lazy_writeout(struct page *page)
284 set_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page));
287 static int bm_test_page_lazy_writeout(struct page *page)
289 return test_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page));
292 /* on a 32bit box, this would allow for exactly (2<<38) bits. */
293 static unsigned int bm_word_to_page_idx(struct drbd_bitmap *b, unsigned long long_nr)
295 /* page_nr = (word*sizeof(long)) >> PAGE_SHIFT; */
296 unsigned int page_nr = long_nr >> (PAGE_SHIFT - LN2_BPL + 3);
297 BUG_ON(page_nr >= b->bm_number_of_pages);
301 static unsigned int bm_bit_to_page_idx(struct drbd_bitmap *b, u64 bitnr)
303 /* page_nr = (bitnr/8) >> PAGE_SHIFT; */
304 unsigned int page_nr = bitnr >> (PAGE_SHIFT + 3);
305 BUG_ON(page_nr >= b->bm_number_of_pages);
309 static unsigned long *__bm_map_pidx(struct drbd_bitmap *b, unsigned int idx)
311 struct page *page = b->bm_pages[idx];
312 return (unsigned long *) kmap_atomic(page);
315 static unsigned long *bm_map_pidx(struct drbd_bitmap *b, unsigned int idx)
317 return __bm_map_pidx(b, idx);
320 static void __bm_unmap(unsigned long *p_addr)
322 kunmap_atomic(p_addr);
325 static void bm_unmap(unsigned long *p_addr)
327 return __bm_unmap(p_addr);
330 /* long word offset of _bitmap_ sector */
331 #define S2W(s) ((s)<<(BM_EXT_SHIFT-BM_BLOCK_SHIFT-LN2_BPL))
332 /* word offset from start of bitmap to word number _in_page_
333 * modulo longs per page
334 #define MLPP(X) ((X) % (PAGE_SIZE/sizeof(long))
335 hm, well, Philipp thinks gcc might not optimize the % into & (... - 1)
338 #define MLPP(X) ((X) & ((PAGE_SIZE/sizeof(long))-1))
340 /* Long words per page */
341 #define LWPP (PAGE_SIZE/sizeof(long))
344 * actually most functions herein should take a struct drbd_bitmap*, not a
345 * struct drbd_device*, but for the debug macros I like to have the device around
346 * to be able to report device specific.
350 static void bm_free_pages(struct page **pages, unsigned long number)
356 for (i = 0; i < number; i++) {
358 pr_alert("bm_free_pages tried to free a NULL pointer; i=%lu n=%lu\n",
362 __free_page(pages[i]);
367 static void bm_vk_free(void *ptr, int v)
376 * "have" and "want" are NUMBER OF PAGES.
378 static struct page **bm_realloc_pages(struct drbd_bitmap *b, unsigned long want)
380 struct page **old_pages = b->bm_pages;
381 struct page **new_pages, *page;
382 unsigned int i, bytes, vmalloced = 0;
383 unsigned long have = b->bm_number_of_pages;
385 BUG_ON(have == 0 && old_pages != NULL);
386 BUG_ON(have != 0 && old_pages == NULL);
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);
399 new_pages = __vmalloc(bytes,
400 GFP_NOIO | __GFP_HIGHMEM | __GFP_ZERO,
408 for (i = 0; i < have; i++)
409 new_pages[i] = old_pages[i];
410 for (; i < want; i++) {
411 page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
413 bm_free_pages(new_pages + have, i - have);
414 bm_vk_free(new_pages, vmalloced);
417 /* we want to know which page it is
418 * from the endio handlers */
419 bm_store_page_idx(page, i);
423 for (i = 0; i < want; i++)
424 new_pages[i] = old_pages[i];
425 /* NOT HERE, we are outside the spinlock!
426 bm_free_pages(old_pages + want, have - want);
431 b->bm_flags |= BM_P_VMALLOCED;
433 b->bm_flags &= ~BM_P_VMALLOCED;
439 * called on driver init only. TODO call when a device is created.
440 * allocates the drbd_bitmap, and stores it in device->bitmap.
442 int drbd_bm_init(struct drbd_device *device)
444 struct drbd_bitmap *b = device->bitmap;
446 b = kzalloc(sizeof(struct drbd_bitmap), GFP_KERNEL);
449 spin_lock_init(&b->bm_lock);
450 mutex_init(&b->bm_change);
451 init_waitqueue_head(&b->bm_io_wait);
458 sector_t drbd_bm_capacity(struct drbd_device *device)
460 if (!expect(device->bitmap))
462 return device->bitmap->bm_dev_capacity;
465 /* called on driver unload. TODO: call when a device is destroyed.
467 void drbd_bm_cleanup(struct drbd_device *device)
469 if (!expect(device->bitmap))
471 bm_free_pages(device->bitmap->bm_pages, device->bitmap->bm_number_of_pages);
472 bm_vk_free(device->bitmap->bm_pages, (BM_P_VMALLOCED & device->bitmap->bm_flags));
473 kfree(device->bitmap);
474 device->bitmap = NULL;
478 * since (b->bm_bits % BITS_PER_LONG) != 0,
479 * this masks out the remaining bits.
480 * Returns the number of bits cleared.
482 #ifndef BITS_PER_PAGE
483 #define BITS_PER_PAGE (1UL << (PAGE_SHIFT + 3))
484 #define BITS_PER_PAGE_MASK (BITS_PER_PAGE - 1)
486 # if BITS_PER_PAGE != (1UL << (PAGE_SHIFT + 3))
487 # error "ambiguous BITS_PER_PAGE"
490 #define BITS_PER_LONG_MASK (BITS_PER_LONG - 1)
491 static int bm_clear_surplus(struct drbd_bitmap *b)
494 unsigned long *p_addr, *bm;
498 /* number of bits modulo bits per page */
499 tmp = (b->bm_bits & BITS_PER_PAGE_MASK);
500 /* mask the used bits of the word containing the last bit */
501 mask = (1UL << (tmp & BITS_PER_LONG_MASK)) -1;
502 /* bitmap is always stored little endian,
503 * on disk and in core memory alike */
504 mask = cpu_to_lel(mask);
506 p_addr = bm_map_pidx(b, b->bm_number_of_pages - 1);
507 bm = p_addr + (tmp/BITS_PER_LONG);
509 /* If mask != 0, we are not exactly aligned, so bm now points
510 * to the long containing the last bit.
511 * If mask == 0, bm already points to the word immediately
512 * after the last (long word aligned) bit. */
513 cleared = hweight_long(*bm & ~mask);
518 if (BITS_PER_LONG == 32 && ((bm - p_addr) & 1) == 1) {
519 /* on a 32bit arch, we may need to zero out
520 * a padding long to align with a 64bit remote */
521 cleared += hweight_long(*bm);
528 static void bm_set_surplus(struct drbd_bitmap *b)
531 unsigned long *p_addr, *bm;
534 /* number of bits modulo bits per page */
535 tmp = (b->bm_bits & BITS_PER_PAGE_MASK);
536 /* mask the used bits of the word containing the last bit */
537 mask = (1UL << (tmp & BITS_PER_LONG_MASK)) -1;
538 /* bitmap is always stored little endian,
539 * on disk and in core memory alike */
540 mask = cpu_to_lel(mask);
542 p_addr = bm_map_pidx(b, b->bm_number_of_pages - 1);
543 bm = p_addr + (tmp/BITS_PER_LONG);
545 /* If mask != 0, we are not exactly aligned, so bm now points
546 * to the long containing the last bit.
547 * If mask == 0, bm already points to the word immediately
548 * after the last (long word aligned) bit. */
553 if (BITS_PER_LONG == 32 && ((bm - p_addr) & 1) == 1) {
554 /* on a 32bit arch, we may need to zero out
555 * a padding long to align with a 64bit remote */
561 /* you better not modify the bitmap while this is running,
562 * or its results will be stale */
563 static unsigned long bm_count_bits(struct drbd_bitmap *b)
565 unsigned long *p_addr;
566 unsigned long bits = 0;
567 unsigned long mask = (1UL << (b->bm_bits & BITS_PER_LONG_MASK)) -1;
570 /* all but last page */
571 for (idx = 0; idx < b->bm_number_of_pages - 1; idx++) {
572 p_addr = __bm_map_pidx(b, idx);
573 bits += bitmap_weight(p_addr, BITS_PER_PAGE);
577 /* last (or only) page */
578 last_word = ((b->bm_bits - 1) & BITS_PER_PAGE_MASK) >> LN2_BPL;
579 p_addr = __bm_map_pidx(b, idx);
580 bits += bitmap_weight(p_addr, last_word * BITS_PER_LONG);
581 p_addr[last_word] &= cpu_to_lel(mask);
582 bits += hweight_long(p_addr[last_word]);
583 /* 32bit arch, may have an unused padding long */
584 if (BITS_PER_LONG == 32 && (last_word & 1) == 0)
585 p_addr[last_word+1] = 0;
590 /* offset and len in long words.*/
591 static void bm_memset(struct drbd_bitmap *b, size_t offset, int c, size_t len)
593 unsigned long *p_addr, *bm;
599 if (end > b->bm_words) {
600 pr_alert("bm_memset end > bm_words\n");
604 while (offset < end) {
605 do_now = min_t(size_t, ALIGN(offset + 1, LWPP), end) - offset;
606 idx = bm_word_to_page_idx(b, offset);
607 p_addr = bm_map_pidx(b, idx);
608 bm = p_addr + MLPP(offset);
609 if (bm+do_now > p_addr + LWPP) {
610 pr_alert("BUG BUG BUG! p_addr:%p bm:%p do_now:%d\n",
611 p_addr, bm, (int)do_now);
613 memset(bm, c, do_now * sizeof(long));
615 bm_set_page_need_writeout(b->bm_pages[idx]);
620 /* For the layout, see comment above drbd_md_set_sector_offsets(). */
621 static u64 drbd_md_on_disk_bits(struct drbd_backing_dev *ldev)
624 if (ldev->md.al_offset == 8)
625 bitmap_sectors = ldev->md.md_size_sect - ldev->md.bm_offset;
627 bitmap_sectors = ldev->md.al_offset - ldev->md.bm_offset;
628 return bitmap_sectors << (9 + 3);
632 * make sure the bitmap has enough room for the attached storage,
633 * if necessary, resize.
634 * called whenever we may have changed the device size.
635 * returns -ENOMEM if we could not allocate enough memory, 0 on success.
636 * In case this is actually a resize, we copy the old bitmap into the new one.
637 * Otherwise, the bitmap is initialized to all bits set.
639 int drbd_bm_resize(struct drbd_device *device, sector_t capacity, int set_new_bits)
641 struct drbd_bitmap *b = device->bitmap;
642 unsigned long bits, words, owords, obits;
643 unsigned long want, have, onpages; /* number of pages */
644 struct page **npages, **opages = NULL;
645 int err = 0, growing;
646 int opages_vmalloced;
651 drbd_bm_lock(device, "resize", BM_LOCKED_MASK);
653 drbd_info(device, "drbd_bm_resize called with capacity == %llu\n",
654 (unsigned long long)capacity);
656 if (capacity == b->bm_dev_capacity)
659 opages_vmalloced = (BM_P_VMALLOCED & b->bm_flags);
662 spin_lock_irq(&b->bm_lock);
663 opages = b->bm_pages;
664 onpages = b->bm_number_of_pages;
665 owords = b->bm_words;
667 b->bm_number_of_pages =
671 b->bm_dev_capacity = 0;
672 spin_unlock_irq(&b->bm_lock);
673 bm_free_pages(opages, onpages);
674 bm_vk_free(opages, opages_vmalloced);
677 bits = BM_SECT_TO_BIT(ALIGN(capacity, BM_SECT_PER_BIT));
680 words = ALIGN(bits,BITS_PER_LONG) >> LN2_BPL;
681 a 32bit host could present the wrong number of words
684 words = ALIGN(bits, 64) >> LN2_BPL;
686 if (get_ldev(device)) {
687 u64 bits_on_disk = drbd_md_on_disk_bits(device->ldev);
689 if (bits > bits_on_disk) {
690 drbd_info(device, "bits = %lu\n", bits);
691 drbd_info(device, "bits_on_disk = %llu\n", bits_on_disk);
697 want = ALIGN(words*sizeof(long), PAGE_SIZE) >> PAGE_SHIFT;
698 have = b->bm_number_of_pages;
700 D_ASSERT(device, b->bm_pages != NULL);
701 npages = b->bm_pages;
703 if (drbd_insert_fault(device, DRBD_FAULT_BM_ALLOC))
706 npages = bm_realloc_pages(b, want);
714 spin_lock_irq(&b->bm_lock);
715 opages = b->bm_pages;
716 owords = b->bm_words;
719 growing = bits > obits;
720 if (opages && growing && set_new_bits)
723 b->bm_pages = npages;
724 b->bm_number_of_pages = want;
727 b->bm_dev_capacity = capacity;
731 bm_memset(b, owords, 0xff, words-owords);
732 b->bm_set += bits - obits;
734 bm_memset(b, owords, 0x00, words-owords);
739 /* implicit: (opages != NULL) && (opages != npages) */
740 bm_free_pages(opages + want, have - want);
743 (void)bm_clear_surplus(b);
745 spin_unlock_irq(&b->bm_lock);
746 if (opages != npages)
747 bm_vk_free(opages, opages_vmalloced);
749 b->bm_set = bm_count_bits(b);
750 drbd_info(device, "resync bitmap: bits=%lu words=%lu pages=%lu\n", bits, words, want);
753 drbd_bm_unlock(device);
758 * if not protected by other means, return value may be out of date when
759 * leaving this function...
760 * we still need to lock it, since it is important that this returns
761 * bm_set == 0 precisely.
763 * maybe bm_set should be atomic_t ?
765 unsigned long _drbd_bm_total_weight(struct drbd_device *device)
767 struct drbd_bitmap *b = device->bitmap;
773 if (!expect(b->bm_pages))
776 spin_lock_irqsave(&b->bm_lock, flags);
778 spin_unlock_irqrestore(&b->bm_lock, flags);
783 unsigned long drbd_bm_total_weight(struct drbd_device *device)
786 /* if I don't have a disk, I don't know about out-of-sync status */
787 if (!get_ldev_if_state(device, D_NEGOTIATING))
789 s = _drbd_bm_total_weight(device);
794 size_t drbd_bm_words(struct drbd_device *device)
796 struct drbd_bitmap *b = device->bitmap;
799 if (!expect(b->bm_pages))
805 unsigned long drbd_bm_bits(struct drbd_device *device)
807 struct drbd_bitmap *b = device->bitmap;
814 /* merge number words from buffer into the bitmap starting at offset.
815 * buffer[i] is expected to be little endian unsigned long.
816 * bitmap must be locked by drbd_bm_lock.
817 * currently only used from receive_bitmap.
819 void drbd_bm_merge_lel(struct drbd_device *device, size_t offset, size_t number,
820 unsigned long *buffer)
822 struct drbd_bitmap *b = device->bitmap;
823 unsigned long *p_addr, *bm;
824 unsigned long word, bits;
828 end = offset + number;
832 if (!expect(b->bm_pages))
836 WARN_ON(offset >= b->bm_words);
837 WARN_ON(end > b->bm_words);
839 spin_lock_irq(&b->bm_lock);
840 while (offset < end) {
841 do_now = min_t(size_t, ALIGN(offset+1, LWPP), end) - offset;
842 idx = bm_word_to_page_idx(b, offset);
843 p_addr = bm_map_pidx(b, idx);
844 bm = p_addr + MLPP(offset);
847 bits = hweight_long(*bm);
848 word = *bm | *buffer++;
850 b->bm_set += hweight_long(word) - bits;
853 bm_set_page_need_writeout(b->bm_pages[idx]);
855 /* with 32bit <-> 64bit cross-platform connect
856 * this is only correct for current usage,
857 * where we _know_ that we are 64 bit aligned,
858 * and know that this function is used in this way, too...
860 if (end == b->bm_words)
861 b->bm_set -= bm_clear_surplus(b);
862 spin_unlock_irq(&b->bm_lock);
865 /* copy number words from the bitmap starting at offset into the buffer.
866 * buffer[i] will be little endian unsigned long.
868 void drbd_bm_get_lel(struct drbd_device *device, size_t offset, size_t number,
869 unsigned long *buffer)
871 struct drbd_bitmap *b = device->bitmap;
872 unsigned long *p_addr, *bm;
875 end = offset + number;
879 if (!expect(b->bm_pages))
882 spin_lock_irq(&b->bm_lock);
883 if ((offset >= b->bm_words) ||
884 (end > b->bm_words) ||
886 drbd_err(device, "offset=%lu number=%lu bm_words=%lu\n",
887 (unsigned long) offset,
888 (unsigned long) number,
889 (unsigned long) b->bm_words);
891 while (offset < end) {
892 do_now = min_t(size_t, ALIGN(offset+1, LWPP), end) - offset;
893 p_addr = bm_map_pidx(b, bm_word_to_page_idx(b, offset));
894 bm = p_addr + MLPP(offset);
901 spin_unlock_irq(&b->bm_lock);
904 /* set all bits in the bitmap */
905 void drbd_bm_set_all(struct drbd_device *device)
907 struct drbd_bitmap *b = device->bitmap;
910 if (!expect(b->bm_pages))
913 spin_lock_irq(&b->bm_lock);
914 bm_memset(b, 0, 0xff, b->bm_words);
915 (void)bm_clear_surplus(b);
916 b->bm_set = b->bm_bits;
917 spin_unlock_irq(&b->bm_lock);
920 /* clear all bits in the bitmap */
921 void drbd_bm_clear_all(struct drbd_device *device)
923 struct drbd_bitmap *b = device->bitmap;
926 if (!expect(b->bm_pages))
929 spin_lock_irq(&b->bm_lock);
930 bm_memset(b, 0, 0, b->bm_words);
932 spin_unlock_irq(&b->bm_lock);
935 static void drbd_bm_aio_ctx_destroy(struct kref *kref)
937 struct drbd_bm_aio_ctx *ctx = container_of(kref, struct drbd_bm_aio_ctx, kref);
940 spin_lock_irqsave(&ctx->device->resource->req_lock, flags);
941 list_del(&ctx->list);
942 spin_unlock_irqrestore(&ctx->device->resource->req_lock, flags);
943 put_ldev(ctx->device);
947 /* bv_page may be a copy, or may be the original */
948 static void drbd_bm_endio(struct bio *bio)
950 struct drbd_bm_aio_ctx *ctx = bio->bi_private;
951 struct drbd_device *device = ctx->device;
952 struct drbd_bitmap *b = device->bitmap;
953 unsigned int idx = bm_page_to_idx(bio->bi_io_vec[0].bv_page);
955 if ((ctx->flags & BM_AIO_COPY_PAGES) == 0 &&
956 !bm_test_page_unchanged(b->bm_pages[idx]))
957 drbd_warn(device, "bitmap page idx %u changed during IO!\n", idx);
960 /* ctx error will hold the completed-last non-zero error code,
961 * in case error codes differ. */
962 ctx->error = bio->bi_error;
963 bm_set_page_io_err(b->bm_pages[idx]);
964 /* Not identical to on disk version of it.
965 * Is BM_PAGE_IO_ERROR enough? */
966 if (__ratelimit(&drbd_ratelimit_state))
967 drbd_err(device, "IO ERROR %d on bitmap page idx %u\n",
970 bm_clear_page_io_err(b->bm_pages[idx]);
971 dynamic_drbd_dbg(device, "bitmap page idx %u completed\n", idx);
974 bm_page_unlock_io(device, idx);
976 if (ctx->flags & BM_AIO_COPY_PAGES)
977 mempool_free(bio->bi_io_vec[0].bv_page, drbd_md_io_page_pool);
981 if (atomic_dec_and_test(&ctx->in_flight)) {
983 wake_up(&device->misc_wait);
984 kref_put(&ctx->kref, &drbd_bm_aio_ctx_destroy);
988 static void bm_page_io_async(struct drbd_bm_aio_ctx *ctx, int page_nr) __must_hold(local)
990 struct bio *bio = bio_alloc_drbd(GFP_NOIO);
991 struct drbd_device *device = ctx->device;
992 struct drbd_bitmap *b = device->bitmap;
995 unsigned int rw = (ctx->flags & BM_AIO_READ) ? READ : WRITE;
997 sector_t on_disk_sector =
998 device->ldev->md.md_offset + device->ldev->md.bm_offset;
999 on_disk_sector += ((sector_t)page_nr) << (PAGE_SHIFT-9);
1001 /* this might happen with very small
1002 * flexible external meta data device,
1003 * or with PAGE_SIZE > 4k */
1004 len = min_t(unsigned int, PAGE_SIZE,
1005 (drbd_md_last_sector(device->ldev) - on_disk_sector + 1)<<9);
1007 /* serialize IO on this page */
1008 bm_page_lock_io(device, page_nr);
1009 /* before memcpy and submit,
1010 * so it can be redirtied any time */
1011 bm_set_page_unchanged(b->bm_pages[page_nr]);
1013 if (ctx->flags & BM_AIO_COPY_PAGES) {
1014 page = mempool_alloc(drbd_md_io_page_pool, __GFP_HIGHMEM|__GFP_RECLAIM);
1015 copy_highpage(page, b->bm_pages[page_nr]);
1016 bm_store_page_idx(page, page_nr);
1018 page = b->bm_pages[page_nr];
1019 bio->bi_bdev = device->ldev->md_bdev;
1020 bio->bi_iter.bi_sector = on_disk_sector;
1021 /* bio_add_page of a single page to an empty bio will always succeed,
1022 * according to api. Do we want to assert that? */
1023 bio_add_page(bio, page, len, 0);
1024 bio->bi_private = ctx;
1025 bio->bi_end_io = drbd_bm_endio;
1027 if (drbd_insert_fault(device, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD)) {
1031 submit_bio(rw, bio);
1032 /* this should not count as user activity and cause the
1033 * resync to throttle -- see drbd_rs_should_slow_down(). */
1034 atomic_add(len >> 9, &device->rs_sect_ev);
1039 * bm_rw: read/write the whole bitmap from/to its on disk location.
1041 static int bm_rw(struct drbd_device *device, const unsigned int flags, unsigned lazy_writeout_upper_idx) __must_hold(local)
1043 struct drbd_bm_aio_ctx *ctx;
1044 struct drbd_bitmap *b = device->bitmap;
1045 int num_pages, i, count = 0;
1051 * We are protected against bitmap disappearing/resizing by holding an
1052 * ldev reference (caller must have called get_ldev()).
1053 * For read/write, we are protected against changes to the bitmap by
1054 * the bitmap lock (see drbd_bitmap_io).
1055 * For lazy writeout, we don't care for ongoing changes to the bitmap,
1056 * as we submit copies of pages anyways.
1059 ctx = kmalloc(sizeof(struct drbd_bm_aio_ctx), GFP_NOIO);
1063 *ctx = (struct drbd_bm_aio_ctx) {
1065 .start_jif = jiffies,
1066 .in_flight = ATOMIC_INIT(1),
1070 .kref = { ATOMIC_INIT(2) },
1073 if (!get_ldev_if_state(device, D_ATTACHING)) { /* put is in drbd_bm_aio_ctx_destroy() */
1074 drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in bm_rw()\n");
1078 /* Here D_ATTACHING is sufficient since drbd_bm_read() is called only from
1079 drbd_adm_attach(), after device->ldev was assigned. */
1081 if (0 == (ctx->flags & ~BM_AIO_READ))
1082 WARN_ON(!(BM_LOCKED_MASK & b->bm_flags));
1084 spin_lock_irq(&device->resource->req_lock);
1085 list_add_tail(&ctx->list, &device->pending_bitmap_io);
1086 spin_unlock_irq(&device->resource->req_lock);
1088 num_pages = b->bm_number_of_pages;
1092 /* let the layers below us try to merge these bios... */
1093 for (i = 0; i < num_pages; i++) {
1094 /* ignore completely unchanged pages */
1095 if (lazy_writeout_upper_idx && i == lazy_writeout_upper_idx)
1097 if (!(flags & BM_AIO_READ)) {
1098 if ((flags & BM_AIO_WRITE_HINTED) &&
1099 !test_and_clear_bit(BM_PAGE_HINT_WRITEOUT,
1100 &page_private(b->bm_pages[i])))
1103 if (!(flags & BM_AIO_WRITE_ALL_PAGES) &&
1104 bm_test_page_unchanged(b->bm_pages[i])) {
1105 dynamic_drbd_dbg(device, "skipped bm write for idx %u\n", i);
1108 /* during lazy writeout,
1109 * ignore those pages not marked for lazy writeout. */
1110 if (lazy_writeout_upper_idx &&
1111 !bm_test_page_lazy_writeout(b->bm_pages[i])) {
1112 dynamic_drbd_dbg(device, "skipped bm lazy write for idx %u\n", i);
1116 atomic_inc(&ctx->in_flight);
1117 bm_page_io_async(ctx, i);
1123 * We initialize ctx->in_flight to one to make sure drbd_bm_endio
1124 * will not set ctx->done early, and decrement / test it here. If there
1125 * are still some bios in flight, we need to wait for them here.
1126 * If all IO is done already (or nothing had been submitted), there is
1127 * no need to wait. Still, we need to put the kref associated with the
1128 * "in_flight reached zero, all done" event.
1130 if (!atomic_dec_and_test(&ctx->in_flight))
1131 wait_until_done_or_force_detached(device, device->ldev, &ctx->done);
1133 kref_put(&ctx->kref, &drbd_bm_aio_ctx_destroy);
1135 /* summary for global bitmap IO */
1137 drbd_info(device, "bitmap %s of %u pages took %lu jiffies\n",
1138 (flags & BM_AIO_READ) ? "READ" : "WRITE",
1139 count, jiffies - now);
1142 drbd_alert(device, "we had at least one MD IO ERROR during bitmap IO\n");
1143 drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR);
1144 err = -EIO; /* ctx->error ? */
1147 if (atomic_read(&ctx->in_flight))
1148 err = -EIO; /* Disk timeout/force-detach during IO... */
1151 if (flags & BM_AIO_READ) {
1152 b->bm_set = bm_count_bits(b);
1153 drbd_info(device, "recounting of set bits took additional %lu jiffies\n",
1158 if ((flags & ~BM_AIO_READ) == 0)
1159 drbd_info(device, "%s (%lu bits) marked out-of-sync by on disk bit-map.\n",
1160 ppsize(ppb, now << (BM_BLOCK_SHIFT-10)), now);
1162 kref_put(&ctx->kref, &drbd_bm_aio_ctx_destroy);
1167 * drbd_bm_read() - Read the whole bitmap from its on disk location.
1168 * @device: DRBD device.
1170 int drbd_bm_read(struct drbd_device *device) __must_hold(local)
1172 return bm_rw(device, BM_AIO_READ, 0);
1176 * drbd_bm_write() - Write the whole bitmap to its on disk location.
1177 * @device: DRBD device.
1179 * Will only write pages that have changed since last IO.
1181 int drbd_bm_write(struct drbd_device *device) __must_hold(local)
1183 return bm_rw(device, 0, 0);
1187 * drbd_bm_write_all() - Write the whole bitmap to its on disk location.
1188 * @device: DRBD device.
1190 * Will write all pages.
1192 int drbd_bm_write_all(struct drbd_device *device) __must_hold(local)
1194 return bm_rw(device, BM_AIO_WRITE_ALL_PAGES, 0);
1198 * drbd_bm_write_lazy() - Write bitmap pages 0 to @upper_idx-1, if they have changed.
1199 * @device: DRBD device.
1200 * @upper_idx: 0: write all changed pages; +ve: page index to stop scanning for changed pages
1202 int drbd_bm_write_lazy(struct drbd_device *device, unsigned upper_idx) __must_hold(local)
1204 return bm_rw(device, BM_AIO_COPY_PAGES, upper_idx);
1208 * drbd_bm_write_copy_pages() - Write the whole bitmap to its on disk location.
1209 * @device: DRBD device.
1211 * Will only write pages that have changed since last IO.
1212 * In contrast to drbd_bm_write(), this will copy the bitmap pages
1213 * to temporary writeout pages. It is intended to trigger a full write-out
1214 * while still allowing the bitmap to change, for example if a resync or online
1215 * verify is aborted due to a failed peer disk, while local IO continues, or
1216 * pending resync acks are still being processed.
1218 int drbd_bm_write_copy_pages(struct drbd_device *device) __must_hold(local)
1220 return bm_rw(device, BM_AIO_COPY_PAGES, 0);
1224 * drbd_bm_write_hinted() - Write bitmap pages with "hint" marks, if they have changed.
1225 * @device: DRBD device.
1227 int drbd_bm_write_hinted(struct drbd_device *device) __must_hold(local)
1229 return bm_rw(device, BM_AIO_WRITE_HINTED | BM_AIO_COPY_PAGES, 0);
1233 * find_first_bit returns int, we return unsigned long.
1234 * For this to work on 32bit arch with bitnumbers > (1<<32),
1235 * we'd need to return u64, and get a whole lot of other places
1236 * fixed where we still use unsigned long.
1238 * this returns a bit number, NOT a sector!
1240 static unsigned long __bm_find_next(struct drbd_device *device, unsigned long bm_fo,
1241 const int find_zero_bit)
1243 struct drbd_bitmap *b = device->bitmap;
1244 unsigned long *p_addr;
1245 unsigned long bit_offset;
1249 if (bm_fo > b->bm_bits) {
1250 drbd_err(device, "bm_fo=%lu bm_bits=%lu\n", bm_fo, b->bm_bits);
1251 bm_fo = DRBD_END_OF_BITMAP;
1253 while (bm_fo < b->bm_bits) {
1254 /* bit offset of the first bit in the page */
1255 bit_offset = bm_fo & ~BITS_PER_PAGE_MASK;
1256 p_addr = __bm_map_pidx(b, bm_bit_to_page_idx(b, bm_fo));
1259 i = find_next_zero_bit_le(p_addr,
1260 PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK);
1262 i = find_next_bit_le(p_addr,
1263 PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK);
1266 if (i < PAGE_SIZE*8) {
1267 bm_fo = bit_offset + i;
1268 if (bm_fo >= b->bm_bits)
1272 bm_fo = bit_offset + PAGE_SIZE*8;
1274 bm_fo = DRBD_END_OF_BITMAP;
1280 static unsigned long bm_find_next(struct drbd_device *device,
1281 unsigned long bm_fo, const int find_zero_bit)
1283 struct drbd_bitmap *b = device->bitmap;
1284 unsigned long i = DRBD_END_OF_BITMAP;
1288 if (!expect(b->bm_pages))
1291 spin_lock_irq(&b->bm_lock);
1292 if (BM_DONT_TEST & b->bm_flags)
1293 bm_print_lock_info(device);
1295 i = __bm_find_next(device, bm_fo, find_zero_bit);
1297 spin_unlock_irq(&b->bm_lock);
1301 unsigned long drbd_bm_find_next(struct drbd_device *device, unsigned long bm_fo)
1303 return bm_find_next(device, bm_fo, 0);
1307 /* not yet needed for anything. */
1308 unsigned long drbd_bm_find_next_zero(struct drbd_device *device, unsigned long bm_fo)
1310 return bm_find_next(device, bm_fo, 1);
1314 /* does not spin_lock_irqsave.
1315 * you must take drbd_bm_lock() first */
1316 unsigned long _drbd_bm_find_next(struct drbd_device *device, unsigned long bm_fo)
1318 /* WARN_ON(!(BM_DONT_SET & device->b->bm_flags)); */
1319 return __bm_find_next(device, bm_fo, 0);
1322 unsigned long _drbd_bm_find_next_zero(struct drbd_device *device, unsigned long bm_fo)
1324 /* WARN_ON(!(BM_DONT_SET & device->b->bm_flags)); */
1325 return __bm_find_next(device, bm_fo, 1);
1328 /* returns number of bits actually changed.
1329 * for val != 0, we change 0 -> 1, return code positive
1330 * for val == 0, we change 1 -> 0, return code negative
1331 * wants bitnr, not sector.
1332 * expected to be called for only a few bits (e - s about BITS_PER_LONG).
1333 * Must hold bitmap lock already. */
1334 static int __bm_change_bits_to(struct drbd_device *device, const unsigned long s,
1335 unsigned long e, int val)
1337 struct drbd_bitmap *b = device->bitmap;
1338 unsigned long *p_addr = NULL;
1339 unsigned long bitnr;
1340 unsigned int last_page_nr = -1U;
1342 int changed_total = 0;
1344 if (e >= b->bm_bits) {
1345 drbd_err(device, "ASSERT FAILED: bit_s=%lu bit_e=%lu bm_bits=%lu\n",
1347 e = b->bm_bits ? b->bm_bits -1 : 0;
1349 for (bitnr = s; bitnr <= e; bitnr++) {
1350 unsigned int page_nr = bm_bit_to_page_idx(b, bitnr);
1351 if (page_nr != last_page_nr) {
1355 bm_set_page_lazy_writeout(b->bm_pages[last_page_nr]);
1357 bm_set_page_need_writeout(b->bm_pages[last_page_nr]);
1360 p_addr = __bm_map_pidx(b, page_nr);
1361 last_page_nr = page_nr;
1364 c += (0 == __test_and_set_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr));
1366 c -= (0 != __test_and_clear_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr));
1371 bm_set_page_lazy_writeout(b->bm_pages[last_page_nr]);
1373 bm_set_page_need_writeout(b->bm_pages[last_page_nr]);
1375 b->bm_set += changed_total;
1376 return changed_total;
1379 /* returns number of bits actually changed.
1380 * for val != 0, we change 0 -> 1, return code positive
1381 * for val == 0, we change 1 -> 0, return code negative
1382 * wants bitnr, not sector */
1383 static int bm_change_bits_to(struct drbd_device *device, const unsigned long s,
1384 const unsigned long e, int val)
1386 unsigned long flags;
1387 struct drbd_bitmap *b = device->bitmap;
1392 if (!expect(b->bm_pages))
1395 spin_lock_irqsave(&b->bm_lock, flags);
1396 if ((val ? BM_DONT_SET : BM_DONT_CLEAR) & b->bm_flags)
1397 bm_print_lock_info(device);
1399 c = __bm_change_bits_to(device, s, e, val);
1401 spin_unlock_irqrestore(&b->bm_lock, flags);
1405 /* returns number of bits changed 0 -> 1 */
1406 int drbd_bm_set_bits(struct drbd_device *device, const unsigned long s, const unsigned long e)
1408 return bm_change_bits_to(device, s, e, 1);
1411 /* returns number of bits changed 1 -> 0 */
1412 int drbd_bm_clear_bits(struct drbd_device *device, const unsigned long s, const unsigned long e)
1414 return -bm_change_bits_to(device, s, e, 0);
1417 /* sets all bits in full words,
1418 * from first_word up to, but not including, last_word */
1419 static inline void bm_set_full_words_within_one_page(struct drbd_bitmap *b,
1420 int page_nr, int first_word, int last_word)
1425 unsigned long *paddr = kmap_atomic(b->bm_pages[page_nr]);
1427 /* I think it is more cache line friendly to hweight_long then set to ~0UL,
1428 * than to first bitmap_weight() all words, then bitmap_fill() all words */
1429 for (i = first_word; i < last_word; i++) {
1430 bits = hweight_long(paddr[i]);
1432 changed += BITS_PER_LONG - bits;
1434 kunmap_atomic(paddr);
1436 /* We only need lazy writeout, the information is still in the
1437 * remote bitmap as well, and is reconstructed during the next
1438 * bitmap exchange, if lost locally due to a crash. */
1439 bm_set_page_lazy_writeout(b->bm_pages[page_nr]);
1440 b->bm_set += changed;
1444 /* Same thing as drbd_bm_set_bits,
1445 * but more efficient for a large bit range.
1446 * You must first drbd_bm_lock().
1447 * Can be called to set the whole bitmap in one go.
1448 * Sets bits from s to e _inclusive_. */
1449 void _drbd_bm_set_bits(struct drbd_device *device, const unsigned long s, const unsigned long e)
1451 /* First set_bit from the first bit (s)
1452 * up to the next long boundary (sl),
1453 * then assign full words up to the last long boundary (el),
1454 * then set_bit up to and including the last bit (e).
1456 * Do not use memset, because we must account for changes,
1457 * so we need to loop over the words with hweight() anyways.
1459 struct drbd_bitmap *b = device->bitmap;
1460 unsigned long sl = ALIGN(s,BITS_PER_LONG);
1461 unsigned long el = (e+1) & ~((unsigned long)BITS_PER_LONG-1);
1468 if (e - s <= 3*BITS_PER_LONG) {
1469 /* don't bother; el and sl may even be wrong. */
1470 spin_lock_irq(&b->bm_lock);
1471 __bm_change_bits_to(device, s, e, 1);
1472 spin_unlock_irq(&b->bm_lock);
1476 /* difference is large enough that we can trust sl and el */
1478 spin_lock_irq(&b->bm_lock);
1480 /* bits filling the current long */
1482 __bm_change_bits_to(device, s, sl-1, 1);
1484 first_page = sl >> (3 + PAGE_SHIFT);
1485 last_page = el >> (3 + PAGE_SHIFT);
1487 /* MLPP: modulo longs per page */
1488 /* LWPP: long words per page */
1489 first_word = MLPP(sl >> LN2_BPL);
1492 /* first and full pages, unless first page == last page */
1493 for (page_nr = first_page; page_nr < last_page; page_nr++) {
1494 bm_set_full_words_within_one_page(device->bitmap, page_nr, first_word, last_word);
1495 spin_unlock_irq(&b->bm_lock);
1498 spin_lock_irq(&b->bm_lock);
1500 /* last page (respectively only page, for first page == last page) */
1501 last_word = MLPP(el >> LN2_BPL);
1503 /* consider bitmap->bm_bits = 32768, bitmap->bm_number_of_pages = 1. (or multiples).
1504 * ==> e = 32767, el = 32768, last_page = 2,
1505 * and now last_word = 0.
1506 * We do not want to touch last_page in this case,
1507 * as we did not allocate it, it is not present in bitmap->bm_pages.
1510 bm_set_full_words_within_one_page(device->bitmap, last_page, first_word, last_word);
1512 /* possibly trailing bits.
1513 * example: (e & 63) == 63, el will be e+1.
1514 * if that even was the very last bit,
1515 * it would trigger an assert in __bm_change_bits_to()
1518 __bm_change_bits_to(device, el, e, 1);
1519 spin_unlock_irq(&b->bm_lock);
1522 /* returns bit state
1523 * wants bitnr, NOT sector.
1524 * inherently racy... area needs to be locked by means of {al,rs}_lru
1527 * -1 ... first out of bounds access, stop testing for bits!
1529 int drbd_bm_test_bit(struct drbd_device *device, const unsigned long bitnr)
1531 unsigned long flags;
1532 struct drbd_bitmap *b = device->bitmap;
1533 unsigned long *p_addr;
1538 if (!expect(b->bm_pages))
1541 spin_lock_irqsave(&b->bm_lock, flags);
1542 if (BM_DONT_TEST & b->bm_flags)
1543 bm_print_lock_info(device);
1544 if (bitnr < b->bm_bits) {
1545 p_addr = bm_map_pidx(b, bm_bit_to_page_idx(b, bitnr));
1546 i = test_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr) ? 1 : 0;
1548 } else if (bitnr == b->bm_bits) {
1550 } else { /* (bitnr > b->bm_bits) */
1551 drbd_err(device, "bitnr=%lu > bm_bits=%lu\n", bitnr, b->bm_bits);
1555 spin_unlock_irqrestore(&b->bm_lock, flags);
1559 /* returns number of bits set in the range [s, e] */
1560 int drbd_bm_count_bits(struct drbd_device *device, const unsigned long s, const unsigned long e)
1562 unsigned long flags;
1563 struct drbd_bitmap *b = device->bitmap;
1564 unsigned long *p_addr = NULL;
1565 unsigned long bitnr;
1566 unsigned int page_nr = -1U;
1569 /* If this is called without a bitmap, that is a bug. But just to be
1570 * robust in case we screwed up elsewhere, in that case pretend there
1571 * was one dirty bit in the requested area, so we won't try to do a
1572 * local read there (no bitmap probably implies no disk) */
1575 if (!expect(b->bm_pages))
1578 spin_lock_irqsave(&b->bm_lock, flags);
1579 if (BM_DONT_TEST & b->bm_flags)
1580 bm_print_lock_info(device);
1581 for (bitnr = s; bitnr <= e; bitnr++) {
1582 unsigned int idx = bm_bit_to_page_idx(b, bitnr);
1583 if (page_nr != idx) {
1587 p_addr = bm_map_pidx(b, idx);
1589 if (expect(bitnr < b->bm_bits))
1590 c += (0 != test_bit_le(bitnr - (page_nr << (PAGE_SHIFT+3)), p_addr));
1592 drbd_err(device, "bitnr=%lu bm_bits=%lu\n", bitnr, b->bm_bits);
1596 spin_unlock_irqrestore(&b->bm_lock, flags);
1601 /* inherently racy...
1602 * return value may be already out-of-date when this function returns.
1603 * but the general usage is that this is only use during a cstate when bits are
1604 * only cleared, not set, and typically only care for the case when the return
1605 * value is zero, or we already "locked" this "bitmap extent" by other means.
1607 * enr is bm-extent number, since we chose to name one sector (512 bytes)
1608 * worth of the bitmap a "bitmap extent".
1611 * I think since we use it like a reference count, we should use the real
1612 * reference count of some bitmap extent element from some lru instead...
1615 int drbd_bm_e_weight(struct drbd_device *device, unsigned long enr)
1617 struct drbd_bitmap *b = device->bitmap;
1619 unsigned long flags;
1620 unsigned long *p_addr, *bm;
1624 if (!expect(b->bm_pages))
1627 spin_lock_irqsave(&b->bm_lock, flags);
1628 if (BM_DONT_TEST & b->bm_flags)
1629 bm_print_lock_info(device);
1632 e = min((size_t)S2W(enr+1), b->bm_words);
1634 if (s < b->bm_words) {
1636 p_addr = bm_map_pidx(b, bm_word_to_page_idx(b, s));
1637 bm = p_addr + MLPP(s);
1638 count += bitmap_weight(bm, n * BITS_PER_LONG);
1641 drbd_err(device, "start offset (%d) too large in drbd_bm_e_weight\n", s);
1643 spin_unlock_irqrestore(&b->bm_lock, flags);