| /* |
| drbd_bitmap.c |
| |
| This file is part of DRBD by Philipp Reisner and Lars Ellenberg. |
| |
| Copyright (C) 2004-2008, LINBIT Information Technologies GmbH. |
| Copyright (C) 2004-2008, Philipp Reisner <philipp.reisner@linbit.com>. |
| Copyright (C) 2004-2008, Lars Ellenberg <lars.ellenberg@linbit.com>. |
| |
| drbd is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| drbd is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with drbd; see the file COPYING. If not, write to |
| the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/bitops.h> |
| #include <linux/vmalloc.h> |
| #include <linux/string.h> |
| #include <linux/drbd.h> |
| #include <linux/slab.h> |
| #include <asm/kmap_types.h> |
| |
| #include "drbd_int.h" |
| |
| |
| /* OPAQUE outside this file! |
| * interface defined in drbd_int.h |
| |
| * convention: |
| * function name drbd_bm_... => used elsewhere, "public". |
| * function name bm_... => internal to implementation, "private". |
| */ |
| |
| |
| /* |
| * LIMITATIONS: |
| * We want to support >= peta byte of backend storage, while for now still using |
| * a granularity of one bit per 4KiB of storage. |
| * 1 << 50 bytes backend storage (1 PiB) |
| * 1 << (50 - 12) bits needed |
| * 38 --> we need u64 to index and count bits |
| * 1 << (38 - 3) bitmap bytes needed |
| * 35 --> we still need u64 to index and count bytes |
| * (that's 32 GiB of bitmap for 1 PiB storage) |
| * 1 << (35 - 2) 32bit longs needed |
| * 33 --> we'd even need u64 to index and count 32bit long words. |
| * 1 << (35 - 3) 64bit longs needed |
| * 32 --> we could get away with a 32bit unsigned int to index and count |
| * 64bit long words, but I rather stay with unsigned long for now. |
| * We probably should neither count nor point to bytes or long words |
| * directly, but either by bitnumber, or by page index and offset. |
| * 1 << (35 - 12) |
| * 22 --> we need that much 4KiB pages of bitmap. |
| * 1 << (22 + 3) --> on a 64bit arch, |
| * we need 32 MiB to store the array of page pointers. |
| * |
| * Because I'm lazy, and because the resulting patch was too large, too ugly |
| * and still incomplete, on 32bit we still "only" support 16 TiB (minus some), |
| * (1 << 32) bits * 4k storage. |
| * |
| |
| * bitmap storage and IO: |
| * Bitmap is stored little endian on disk, and is kept little endian in |
| * core memory. Currently we still hold the full bitmap in core as long |
| * as we are "attached" to a local disk, which at 32 GiB for 1PiB storage |
| * seems excessive. |
| * |
| * We plan to reduce the amount of in-core bitmap pages by paging them in |
| * and out against their on-disk location as necessary, but need to make |
| * sure we don't cause too much meta data IO, and must not deadlock in |
| * tight memory situations. This needs some more work. |
| */ |
| |
| /* |
| * NOTE |
| * Access to the *bm_pages is protected by bm_lock. |
| * It is safe to read the other members within the lock. |
| * |
| * drbd_bm_set_bits is called from bio_endio callbacks, |
| * We may be called with irq already disabled, |
| * so we need spin_lock_irqsave(). |
| * And we need the kmap_atomic. |
| */ |
| struct drbd_bitmap { |
| struct page **bm_pages; |
| spinlock_t bm_lock; |
| |
| /* see LIMITATIONS: above */ |
| |
| unsigned long bm_set; /* nr of set bits; THINK maybe atomic_t? */ |
| unsigned long bm_bits; |
| size_t bm_words; |
| size_t bm_number_of_pages; |
| sector_t bm_dev_capacity; |
| struct mutex bm_change; /* serializes resize operations */ |
| |
| wait_queue_head_t bm_io_wait; /* used to serialize IO of single pages */ |
| |
| enum bm_flag bm_flags; |
| |
| /* debugging aid, in case we are still racy somewhere */ |
| char *bm_why; |
| struct task_struct *bm_task; |
| }; |
| |
| #define bm_print_lock_info(m) __bm_print_lock_info(m, __func__) |
| static void __bm_print_lock_info(struct drbd_device *device, const char *func) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| if (!__ratelimit(&drbd_ratelimit_state)) |
| return; |
| drbd_err(device, "FIXME %s[%d] in %s, bitmap locked for '%s' by %s[%d]\n", |
| current->comm, task_pid_nr(current), |
| func, b->bm_why ?: "?", |
| b->bm_task->comm, task_pid_nr(b->bm_task)); |
| } |
| |
| void drbd_bm_lock(struct drbd_device *device, char *why, enum bm_flag flags) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| int trylock_failed; |
| |
| if (!b) { |
| drbd_err(device, "FIXME no bitmap in drbd_bm_lock!?\n"); |
| return; |
| } |
| |
| trylock_failed = !mutex_trylock(&b->bm_change); |
| |
| if (trylock_failed) { |
| drbd_warn(device, "%s[%d] going to '%s' but bitmap already locked for '%s' by %s[%d]\n", |
| current->comm, task_pid_nr(current), |
| why, b->bm_why ?: "?", |
| b->bm_task->comm, task_pid_nr(b->bm_task)); |
| mutex_lock(&b->bm_change); |
| } |
| if (BM_LOCKED_MASK & b->bm_flags) |
| drbd_err(device, "FIXME bitmap already locked in bm_lock\n"); |
| b->bm_flags |= flags & BM_LOCKED_MASK; |
| |
| b->bm_why = why; |
| b->bm_task = current; |
| } |
| |
| void drbd_bm_unlock(struct drbd_device *device) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| if (!b) { |
| drbd_err(device, "FIXME no bitmap in drbd_bm_unlock!?\n"); |
| return; |
| } |
| |
| if (!(BM_LOCKED_MASK & device->bitmap->bm_flags)) |
| drbd_err(device, "FIXME bitmap not locked in bm_unlock\n"); |
| |
| b->bm_flags &= ~BM_LOCKED_MASK; |
| b->bm_why = NULL; |
| b->bm_task = NULL; |
| mutex_unlock(&b->bm_change); |
| } |
| |
| /* we store some "meta" info about our pages in page->private */ |
| /* at a granularity of 4k storage per bitmap bit: |
| * one peta byte storage: 1<<50 byte, 1<<38 * 4k storage blocks |
| * 1<<38 bits, |
| * 1<<23 4k bitmap pages. |
| * Use 24 bits as page index, covers 2 peta byte storage |
| * at a granularity of 4k per bit. |
| * Used to report the failed page idx on io error from the endio handlers. |
| */ |
| #define BM_PAGE_IDX_MASK ((1UL<<24)-1) |
| /* this page is currently read in, or written back */ |
| #define BM_PAGE_IO_LOCK 31 |
| /* if there has been an IO error for this page */ |
| #define BM_PAGE_IO_ERROR 30 |
| /* this is to be able to intelligently skip disk IO, |
| * set if bits have been set since last IO. */ |
| #define BM_PAGE_NEED_WRITEOUT 29 |
| /* to mark for lazy writeout once syncer cleared all clearable bits, |
| * we if bits have been cleared since last IO. */ |
| #define BM_PAGE_LAZY_WRITEOUT 28 |
| /* pages marked with this "HINT" will be considered for writeout |
| * on activity log transactions */ |
| #define BM_PAGE_HINT_WRITEOUT 27 |
| |
| /* store_page_idx uses non-atomic assignment. It is only used directly after |
| * allocating the page. All other bm_set_page_* and bm_clear_page_* need to |
| * use atomic bit manipulation, as set_out_of_sync (and therefore bitmap |
| * changes) may happen from various contexts, and wait_on_bit/wake_up_bit |
| * requires it all to be atomic as well. */ |
| static void bm_store_page_idx(struct page *page, unsigned long idx) |
| { |
| BUG_ON(0 != (idx & ~BM_PAGE_IDX_MASK)); |
| set_page_private(page, idx); |
| } |
| |
| static unsigned long bm_page_to_idx(struct page *page) |
| { |
| return page_private(page) & BM_PAGE_IDX_MASK; |
| } |
| |
| /* As is very unlikely that the same page is under IO from more than one |
| * context, we can get away with a bit per page and one wait queue per bitmap. |
| */ |
| static void bm_page_lock_io(struct drbd_device *device, int page_nr) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| void *addr = &page_private(b->bm_pages[page_nr]); |
| wait_event(b->bm_io_wait, !test_and_set_bit(BM_PAGE_IO_LOCK, addr)); |
| } |
| |
| static void bm_page_unlock_io(struct drbd_device *device, int page_nr) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| void *addr = &page_private(b->bm_pages[page_nr]); |
| clear_bit_unlock(BM_PAGE_IO_LOCK, addr); |
| wake_up(&device->bitmap->bm_io_wait); |
| } |
| |
| /* set _before_ submit_io, so it may be reset due to being changed |
| * while this page is in flight... will get submitted later again */ |
| static void bm_set_page_unchanged(struct page *page) |
| { |
| /* use cmpxchg? */ |
| clear_bit(BM_PAGE_NEED_WRITEOUT, &page_private(page)); |
| clear_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page)); |
| } |
| |
| static void bm_set_page_need_writeout(struct page *page) |
| { |
| set_bit(BM_PAGE_NEED_WRITEOUT, &page_private(page)); |
| } |
| |
| /** |
| * drbd_bm_mark_for_writeout() - mark a page with a "hint" to be considered for writeout |
| * @device: DRBD device. |
| * @page_nr: the bitmap page to mark with the "hint" flag |
| * |
| * From within an activity log transaction, we mark a few pages with these |
| * hints, then call drbd_bm_write_hinted(), which will only write out changed |
| * pages which are flagged with this mark. |
| */ |
| void drbd_bm_mark_for_writeout(struct drbd_device *device, int page_nr) |
| { |
| struct page *page; |
| if (page_nr >= device->bitmap->bm_number_of_pages) { |
| drbd_warn(device, "BAD: page_nr: %u, number_of_pages: %u\n", |
| page_nr, (int)device->bitmap->bm_number_of_pages); |
| return; |
| } |
| page = device->bitmap->bm_pages[page_nr]; |
| set_bit(BM_PAGE_HINT_WRITEOUT, &page_private(page)); |
| } |
| |
| static int bm_test_page_unchanged(struct page *page) |
| { |
| volatile const unsigned long *addr = &page_private(page); |
| return (*addr & ((1UL<<BM_PAGE_NEED_WRITEOUT)|(1UL<<BM_PAGE_LAZY_WRITEOUT))) == 0; |
| } |
| |
| static void bm_set_page_io_err(struct page *page) |
| { |
| set_bit(BM_PAGE_IO_ERROR, &page_private(page)); |
| } |
| |
| static void bm_clear_page_io_err(struct page *page) |
| { |
| clear_bit(BM_PAGE_IO_ERROR, &page_private(page)); |
| } |
| |
| static void bm_set_page_lazy_writeout(struct page *page) |
| { |
| set_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page)); |
| } |
| |
| static int bm_test_page_lazy_writeout(struct page *page) |
| { |
| return test_bit(BM_PAGE_LAZY_WRITEOUT, &page_private(page)); |
| } |
| |
| /* on a 32bit box, this would allow for exactly (2<<38) bits. */ |
| static unsigned int bm_word_to_page_idx(struct drbd_bitmap *b, unsigned long long_nr) |
| { |
| /* page_nr = (word*sizeof(long)) >> PAGE_SHIFT; */ |
| unsigned int page_nr = long_nr >> (PAGE_SHIFT - LN2_BPL + 3); |
| BUG_ON(page_nr >= b->bm_number_of_pages); |
| return page_nr; |
| } |
| |
| static unsigned int bm_bit_to_page_idx(struct drbd_bitmap *b, u64 bitnr) |
| { |
| /* page_nr = (bitnr/8) >> PAGE_SHIFT; */ |
| unsigned int page_nr = bitnr >> (PAGE_SHIFT + 3); |
| BUG_ON(page_nr >= b->bm_number_of_pages); |
| return page_nr; |
| } |
| |
| static unsigned long *__bm_map_pidx(struct drbd_bitmap *b, unsigned int idx) |
| { |
| struct page *page = b->bm_pages[idx]; |
| return (unsigned long *) kmap_atomic(page); |
| } |
| |
| static unsigned long *bm_map_pidx(struct drbd_bitmap *b, unsigned int idx) |
| { |
| return __bm_map_pidx(b, idx); |
| } |
| |
| static void __bm_unmap(unsigned long *p_addr) |
| { |
| kunmap_atomic(p_addr); |
| }; |
| |
| static void bm_unmap(unsigned long *p_addr) |
| { |
| return __bm_unmap(p_addr); |
| } |
| |
| /* long word offset of _bitmap_ sector */ |
| #define S2W(s) ((s)<<(BM_EXT_SHIFT-BM_BLOCK_SHIFT-LN2_BPL)) |
| /* word offset from start of bitmap to word number _in_page_ |
| * modulo longs per page |
| #define MLPP(X) ((X) % (PAGE_SIZE/sizeof(long)) |
| hm, well, Philipp thinks gcc might not optimize the % into & (... - 1) |
| so do it explicitly: |
| */ |
| #define MLPP(X) ((X) & ((PAGE_SIZE/sizeof(long))-1)) |
| |
| /* Long words per page */ |
| #define LWPP (PAGE_SIZE/sizeof(long)) |
| |
| /* |
| * actually most functions herein should take a struct drbd_bitmap*, not a |
| * struct drbd_device*, but for the debug macros I like to have the device around |
| * to be able to report device specific. |
| */ |
| |
| |
| static void bm_free_pages(struct page **pages, unsigned long number) |
| { |
| unsigned long i; |
| if (!pages) |
| return; |
| |
| for (i = 0; i < number; i++) { |
| if (!pages[i]) { |
| pr_alert("bm_free_pages tried to free a NULL pointer; i=%lu n=%lu\n", |
| i, number); |
| continue; |
| } |
| __free_page(pages[i]); |
| pages[i] = NULL; |
| } |
| } |
| |
| static void bm_vk_free(void *ptr, int v) |
| { |
| if (v) |
| vfree(ptr); |
| else |
| kfree(ptr); |
| } |
| |
| /* |
| * "have" and "want" are NUMBER OF PAGES. |
| */ |
| static struct page **bm_realloc_pages(struct drbd_bitmap *b, unsigned long want) |
| { |
| struct page **old_pages = b->bm_pages; |
| struct page **new_pages, *page; |
| unsigned int i, bytes, vmalloced = 0; |
| unsigned long have = b->bm_number_of_pages; |
| |
| BUG_ON(have == 0 && old_pages != NULL); |
| BUG_ON(have != 0 && old_pages == NULL); |
| |
| if (have == want) |
| return old_pages; |
| |
| /* Trying kmalloc first, falling back to vmalloc. |
| * GFP_NOIO, as this is called while drbd IO is "suspended", |
| * and during resize or attach on diskless Primary, |
| * we must not block on IO to ourselves. |
| * Context is receiver thread or dmsetup. */ |
| bytes = sizeof(struct page *)*want; |
| new_pages = kzalloc(bytes, GFP_NOIO | __GFP_NOWARN); |
| if (!new_pages) { |
| new_pages = __vmalloc(bytes, |
| GFP_NOIO | __GFP_HIGHMEM | __GFP_ZERO, |
| PAGE_KERNEL); |
| if (!new_pages) |
| return NULL; |
| vmalloced = 1; |
| } |
| |
| if (want >= have) { |
| for (i = 0; i < have; i++) |
| new_pages[i] = old_pages[i]; |
| for (; i < want; i++) { |
| page = alloc_page(GFP_NOIO | __GFP_HIGHMEM); |
| if (!page) { |
| bm_free_pages(new_pages + have, i - have); |
| bm_vk_free(new_pages, vmalloced); |
| return NULL; |
| } |
| /* we want to know which page it is |
| * from the endio handlers */ |
| bm_store_page_idx(page, i); |
| new_pages[i] = page; |
| } |
| } else { |
| for (i = 0; i < want; i++) |
| new_pages[i] = old_pages[i]; |
| /* NOT HERE, we are outside the spinlock! |
| bm_free_pages(old_pages + want, have - want); |
| */ |
| } |
| |
| if (vmalloced) |
| b->bm_flags |= BM_P_VMALLOCED; |
| else |
| b->bm_flags &= ~BM_P_VMALLOCED; |
| |
| return new_pages; |
| } |
| |
| /* |
| * called on driver init only. TODO call when a device is created. |
| * allocates the drbd_bitmap, and stores it in device->bitmap. |
| */ |
| int drbd_bm_init(struct drbd_device *device) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| WARN_ON(b != NULL); |
| b = kzalloc(sizeof(struct drbd_bitmap), GFP_KERNEL); |
| if (!b) |
| return -ENOMEM; |
| spin_lock_init(&b->bm_lock); |
| mutex_init(&b->bm_change); |
| init_waitqueue_head(&b->bm_io_wait); |
| |
| device->bitmap = b; |
| |
| return 0; |
| } |
| |
| sector_t drbd_bm_capacity(struct drbd_device *device) |
| { |
| if (!expect(device->bitmap)) |
| return 0; |
| return device->bitmap->bm_dev_capacity; |
| } |
| |
| /* called on driver unload. TODO: call when a device is destroyed. |
| */ |
| void drbd_bm_cleanup(struct drbd_device *device) |
| { |
| if (!expect(device->bitmap)) |
| return; |
| bm_free_pages(device->bitmap->bm_pages, device->bitmap->bm_number_of_pages); |
| bm_vk_free(device->bitmap->bm_pages, (BM_P_VMALLOCED & device->bitmap->bm_flags)); |
| kfree(device->bitmap); |
| device->bitmap = NULL; |
| } |
| |
| /* |
| * since (b->bm_bits % BITS_PER_LONG) != 0, |
| * this masks out the remaining bits. |
| * Returns the number of bits cleared. |
| */ |
| #define BITS_PER_PAGE (1UL << (PAGE_SHIFT + 3)) |
| #define BITS_PER_PAGE_MASK (BITS_PER_PAGE - 1) |
| #define BITS_PER_LONG_MASK (BITS_PER_LONG - 1) |
| static int bm_clear_surplus(struct drbd_bitmap *b) |
| { |
| unsigned long mask; |
| unsigned long *p_addr, *bm; |
| int tmp; |
| int cleared = 0; |
| |
| /* number of bits modulo bits per page */ |
| tmp = (b->bm_bits & BITS_PER_PAGE_MASK); |
| /* mask the used bits of the word containing the last bit */ |
| mask = (1UL << (tmp & BITS_PER_LONG_MASK)) -1; |
| /* bitmap is always stored little endian, |
| * on disk and in core memory alike */ |
| mask = cpu_to_lel(mask); |
| |
| p_addr = bm_map_pidx(b, b->bm_number_of_pages - 1); |
| bm = p_addr + (tmp/BITS_PER_LONG); |
| if (mask) { |
| /* If mask != 0, we are not exactly aligned, so bm now points |
| * to the long containing the last bit. |
| * If mask == 0, bm already points to the word immediately |
| * after the last (long word aligned) bit. */ |
| cleared = hweight_long(*bm & ~mask); |
| *bm &= mask; |
| bm++; |
| } |
| |
| if (BITS_PER_LONG == 32 && ((bm - p_addr) & 1) == 1) { |
| /* on a 32bit arch, we may need to zero out |
| * a padding long to align with a 64bit remote */ |
| cleared += hweight_long(*bm); |
| *bm = 0; |
| } |
| bm_unmap(p_addr); |
| return cleared; |
| } |
| |
| static void bm_set_surplus(struct drbd_bitmap *b) |
| { |
| unsigned long mask; |
| unsigned long *p_addr, *bm; |
| int tmp; |
| |
| /* number of bits modulo bits per page */ |
| tmp = (b->bm_bits & BITS_PER_PAGE_MASK); |
| /* mask the used bits of the word containing the last bit */ |
| mask = (1UL << (tmp & BITS_PER_LONG_MASK)) -1; |
| /* bitmap is always stored little endian, |
| * on disk and in core memory alike */ |
| mask = cpu_to_lel(mask); |
| |
| p_addr = bm_map_pidx(b, b->bm_number_of_pages - 1); |
| bm = p_addr + (tmp/BITS_PER_LONG); |
| if (mask) { |
| /* If mask != 0, we are not exactly aligned, so bm now points |
| * to the long containing the last bit. |
| * If mask == 0, bm already points to the word immediately |
| * after the last (long word aligned) bit. */ |
| *bm |= ~mask; |
| bm++; |
| } |
| |
| if (BITS_PER_LONG == 32 && ((bm - p_addr) & 1) == 1) { |
| /* on a 32bit arch, we may need to zero out |
| * a padding long to align with a 64bit remote */ |
| *bm = ~0UL; |
| } |
| bm_unmap(p_addr); |
| } |
| |
| /* you better not modify the bitmap while this is running, |
| * or its results will be stale */ |
| static unsigned long bm_count_bits(struct drbd_bitmap *b) |
| { |
| unsigned long *p_addr; |
| unsigned long bits = 0; |
| unsigned long mask = (1UL << (b->bm_bits & BITS_PER_LONG_MASK)) -1; |
| int idx, i, last_word; |
| |
| /* all but last page */ |
| for (idx = 0; idx < b->bm_number_of_pages - 1; idx++) { |
| p_addr = __bm_map_pidx(b, idx); |
| for (i = 0; i < LWPP; i++) |
| bits += hweight_long(p_addr[i]); |
| __bm_unmap(p_addr); |
| cond_resched(); |
| } |
| /* last (or only) page */ |
| last_word = ((b->bm_bits - 1) & BITS_PER_PAGE_MASK) >> LN2_BPL; |
| p_addr = __bm_map_pidx(b, idx); |
| for (i = 0; i < last_word; i++) |
| bits += hweight_long(p_addr[i]); |
| p_addr[last_word] &= cpu_to_lel(mask); |
| bits += hweight_long(p_addr[last_word]); |
| /* 32bit arch, may have an unused padding long */ |
| if (BITS_PER_LONG == 32 && (last_word & 1) == 0) |
| p_addr[last_word+1] = 0; |
| __bm_unmap(p_addr); |
| return bits; |
| } |
| |
| /* offset and len in long words.*/ |
| static void bm_memset(struct drbd_bitmap *b, size_t offset, int c, size_t len) |
| { |
| unsigned long *p_addr, *bm; |
| unsigned int idx; |
| size_t do_now, end; |
| |
| end = offset + len; |
| |
| if (end > b->bm_words) { |
| pr_alert("bm_memset end > bm_words\n"); |
| return; |
| } |
| |
| while (offset < end) { |
| do_now = min_t(size_t, ALIGN(offset + 1, LWPP), end) - offset; |
| idx = bm_word_to_page_idx(b, offset); |
| p_addr = bm_map_pidx(b, idx); |
| bm = p_addr + MLPP(offset); |
| if (bm+do_now > p_addr + LWPP) { |
| pr_alert("BUG BUG BUG! p_addr:%p bm:%p do_now:%d\n", |
| p_addr, bm, (int)do_now); |
| } else |
| memset(bm, c, do_now * sizeof(long)); |
| bm_unmap(p_addr); |
| bm_set_page_need_writeout(b->bm_pages[idx]); |
| offset += do_now; |
| } |
| } |
| |
| /* For the layout, see comment above drbd_md_set_sector_offsets(). */ |
| static u64 drbd_md_on_disk_bits(struct drbd_backing_dev *ldev) |
| { |
| u64 bitmap_sectors; |
| if (ldev->md.al_offset == 8) |
| bitmap_sectors = ldev->md.md_size_sect - ldev->md.bm_offset; |
| else |
| bitmap_sectors = ldev->md.al_offset - ldev->md.bm_offset; |
| return bitmap_sectors << (9 + 3); |
| } |
| |
| /* |
| * make sure the bitmap has enough room for the attached storage, |
| * if necessary, resize. |
| * called whenever we may have changed the device size. |
| * returns -ENOMEM if we could not allocate enough memory, 0 on success. |
| * In case this is actually a resize, we copy the old bitmap into the new one. |
| * Otherwise, the bitmap is initialized to all bits set. |
| */ |
| int drbd_bm_resize(struct drbd_device *device, sector_t capacity, int set_new_bits) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| unsigned long bits, words, owords, obits; |
| unsigned long want, have, onpages; /* number of pages */ |
| struct page **npages, **opages = NULL; |
| int err = 0, growing; |
| int opages_vmalloced; |
| |
| if (!expect(b)) |
| return -ENOMEM; |
| |
| drbd_bm_lock(device, "resize", BM_LOCKED_MASK); |
| |
| drbd_info(device, "drbd_bm_resize called with capacity == %llu\n", |
| (unsigned long long)capacity); |
| |
| if (capacity == b->bm_dev_capacity) |
| goto out; |
| |
| opages_vmalloced = (BM_P_VMALLOCED & b->bm_flags); |
| |
| if (capacity == 0) { |
| spin_lock_irq(&b->bm_lock); |
| opages = b->bm_pages; |
| onpages = b->bm_number_of_pages; |
| owords = b->bm_words; |
| b->bm_pages = NULL; |
| b->bm_number_of_pages = |
| b->bm_set = |
| b->bm_bits = |
| b->bm_words = |
| b->bm_dev_capacity = 0; |
| spin_unlock_irq(&b->bm_lock); |
| bm_free_pages(opages, onpages); |
| bm_vk_free(opages, opages_vmalloced); |
| goto out; |
| } |
| bits = BM_SECT_TO_BIT(ALIGN(capacity, BM_SECT_PER_BIT)); |
| |
| /* if we would use |
| words = ALIGN(bits,BITS_PER_LONG) >> LN2_BPL; |
| a 32bit host could present the wrong number of words |
| to a 64bit host. |
| */ |
| words = ALIGN(bits, 64) >> LN2_BPL; |
| |
| if (get_ldev(device)) { |
| u64 bits_on_disk = drbd_md_on_disk_bits(device->ldev); |
| put_ldev(device); |
| if (bits > bits_on_disk) { |
| drbd_info(device, "bits = %lu\n", bits); |
| drbd_info(device, "bits_on_disk = %llu\n", bits_on_disk); |
| err = -ENOSPC; |
| goto out; |
| } |
| } |
| |
| want = ALIGN(words*sizeof(long), PAGE_SIZE) >> PAGE_SHIFT; |
| have = b->bm_number_of_pages; |
| if (want == have) { |
| D_ASSERT(device, b->bm_pages != NULL); |
| npages = b->bm_pages; |
| } else { |
| if (drbd_insert_fault(device, DRBD_FAULT_BM_ALLOC)) |
| npages = NULL; |
| else |
| npages = bm_realloc_pages(b, want); |
| } |
| |
| if (!npages) { |
| err = -ENOMEM; |
| goto out; |
| } |
| |
| spin_lock_irq(&b->bm_lock); |
| opages = b->bm_pages; |
| owords = b->bm_words; |
| obits = b->bm_bits; |
| |
| growing = bits > obits; |
| if (opages && growing && set_new_bits) |
| bm_set_surplus(b); |
| |
| b->bm_pages = npages; |
| b->bm_number_of_pages = want; |
| b->bm_bits = bits; |
| b->bm_words = words; |
| b->bm_dev_capacity = capacity; |
| |
| if (growing) { |
| if (set_new_bits) { |
| bm_memset(b, owords, 0xff, words-owords); |
| b->bm_set += bits - obits; |
| } else |
| bm_memset(b, owords, 0x00, words-owords); |
| |
| } |
| |
| if (want < have) { |
| /* implicit: (opages != NULL) && (opages != npages) */ |
| bm_free_pages(opages + want, have - want); |
| } |
| |
| (void)bm_clear_surplus(b); |
| |
| spin_unlock_irq(&b->bm_lock); |
| if (opages != npages) |
| bm_vk_free(opages, opages_vmalloced); |
| if (!growing) |
| b->bm_set = bm_count_bits(b); |
| drbd_info(device, "resync bitmap: bits=%lu words=%lu pages=%lu\n", bits, words, want); |
| |
| out: |
| drbd_bm_unlock(device); |
| return err; |
| } |
| |
| /* inherently racy: |
| * if not protected by other means, return value may be out of date when |
| * leaving this function... |
| * we still need to lock it, since it is important that this returns |
| * bm_set == 0 precisely. |
| * |
| * maybe bm_set should be atomic_t ? |
| */ |
| unsigned long _drbd_bm_total_weight(struct drbd_device *device) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| unsigned long s; |
| unsigned long flags; |
| |
| if (!expect(b)) |
| return 0; |
| if (!expect(b->bm_pages)) |
| return 0; |
| |
| spin_lock_irqsave(&b->bm_lock, flags); |
| s = b->bm_set; |
| spin_unlock_irqrestore(&b->bm_lock, flags); |
| |
| return s; |
| } |
| |
| unsigned long drbd_bm_total_weight(struct drbd_device *device) |
| { |
| unsigned long s; |
| /* if I don't have a disk, I don't know about out-of-sync status */ |
| if (!get_ldev_if_state(device, D_NEGOTIATING)) |
| return 0; |
| s = _drbd_bm_total_weight(device); |
| put_ldev(device); |
| return s; |
| } |
| |
| size_t drbd_bm_words(struct drbd_device *device) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| if (!expect(b)) |
| return 0; |
| if (!expect(b->bm_pages)) |
| return 0; |
| |
| return b->bm_words; |
| } |
| |
| unsigned long drbd_bm_bits(struct drbd_device *device) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| if (!expect(b)) |
| return 0; |
| |
| return b->bm_bits; |
| } |
| |
| /* merge number words from buffer into the bitmap starting at offset. |
| * buffer[i] is expected to be little endian unsigned long. |
| * bitmap must be locked by drbd_bm_lock. |
| * currently only used from receive_bitmap. |
| */ |
| void drbd_bm_merge_lel(struct drbd_device *device, size_t offset, size_t number, |
| unsigned long *buffer) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| unsigned long *p_addr, *bm; |
| unsigned long word, bits; |
| unsigned int idx; |
| size_t end, do_now; |
| |
| end = offset + number; |
| |
| if (!expect(b)) |
| return; |
| if (!expect(b->bm_pages)) |
| return; |
| if (number == 0) |
| return; |
| WARN_ON(offset >= b->bm_words); |
| WARN_ON(end > b->bm_words); |
| |
| spin_lock_irq(&b->bm_lock); |
| while (offset < end) { |
| do_now = min_t(size_t, ALIGN(offset+1, LWPP), end) - offset; |
| idx = bm_word_to_page_idx(b, offset); |
| p_addr = bm_map_pidx(b, idx); |
| bm = p_addr + MLPP(offset); |
| offset += do_now; |
| while (do_now--) { |
| bits = hweight_long(*bm); |
| word = *bm | *buffer++; |
| *bm++ = word; |
| b->bm_set += hweight_long(word) - bits; |
| } |
| bm_unmap(p_addr); |
| bm_set_page_need_writeout(b->bm_pages[idx]); |
| } |
| /* with 32bit <-> 64bit cross-platform connect |
| * this is only correct for current usage, |
| * where we _know_ that we are 64 bit aligned, |
| * and know that this function is used in this way, too... |
| */ |
| if (end == b->bm_words) |
| b->bm_set -= bm_clear_surplus(b); |
| spin_unlock_irq(&b->bm_lock); |
| } |
| |
| /* copy number words from the bitmap starting at offset into the buffer. |
| * buffer[i] will be little endian unsigned long. |
| */ |
| void drbd_bm_get_lel(struct drbd_device *device, size_t offset, size_t number, |
| unsigned long *buffer) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| unsigned long *p_addr, *bm; |
| size_t end, do_now; |
| |
| end = offset + number; |
| |
| if (!expect(b)) |
| return; |
| if (!expect(b->bm_pages)) |
| return; |
| |
| spin_lock_irq(&b->bm_lock); |
| if ((offset >= b->bm_words) || |
| (end > b->bm_words) || |
| (number <= 0)) |
| drbd_err(device, "offset=%lu number=%lu bm_words=%lu\n", |
| (unsigned long) offset, |
| (unsigned long) number, |
| (unsigned long) b->bm_words); |
| else { |
| while (offset < end) { |
| do_now = min_t(size_t, ALIGN(offset+1, LWPP), end) - offset; |
| p_addr = bm_map_pidx(b, bm_word_to_page_idx(b, offset)); |
| bm = p_addr + MLPP(offset); |
| offset += do_now; |
| while (do_now--) |
| *buffer++ = *bm++; |
| bm_unmap(p_addr); |
| } |
| } |
| spin_unlock_irq(&b->bm_lock); |
| } |
| |
| /* set all bits in the bitmap */ |
| void drbd_bm_set_all(struct drbd_device *device) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| if (!expect(b)) |
| return; |
| if (!expect(b->bm_pages)) |
| return; |
| |
| spin_lock_irq(&b->bm_lock); |
| bm_memset(b, 0, 0xff, b->bm_words); |
| (void)bm_clear_surplus(b); |
| b->bm_set = b->bm_bits; |
| spin_unlock_irq(&b->bm_lock); |
| } |
| |
| /* clear all bits in the bitmap */ |
| void drbd_bm_clear_all(struct drbd_device *device) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| if (!expect(b)) |
| return; |
| if (!expect(b->bm_pages)) |
| return; |
| |
| spin_lock_irq(&b->bm_lock); |
| bm_memset(b, 0, 0, b->bm_words); |
| b->bm_set = 0; |
| spin_unlock_irq(&b->bm_lock); |
| } |
| |
| static void drbd_bm_aio_ctx_destroy(struct kref *kref) |
| { |
| struct drbd_bm_aio_ctx *ctx = container_of(kref, struct drbd_bm_aio_ctx, kref); |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ctx->device->resource->req_lock, flags); |
| list_del(&ctx->list); |
| spin_unlock_irqrestore(&ctx->device->resource->req_lock, flags); |
| put_ldev(ctx->device); |
| kfree(ctx); |
| } |
| |
| /* bv_page may be a copy, or may be the original */ |
| static void drbd_bm_endio(struct bio *bio) |
| { |
| struct drbd_bm_aio_ctx *ctx = bio->bi_private; |
| struct drbd_device *device = ctx->device; |
| struct drbd_bitmap *b = device->bitmap; |
| unsigned int idx = bm_page_to_idx(bio->bi_io_vec[0].bv_page); |
| |
| if ((ctx->flags & BM_AIO_COPY_PAGES) == 0 && |
| !bm_test_page_unchanged(b->bm_pages[idx])) |
| drbd_warn(device, "bitmap page idx %u changed during IO!\n", idx); |
| |
| if (bio->bi_error) { |
| /* ctx error will hold the completed-last non-zero error code, |
| * in case error codes differ. */ |
| ctx->error = bio->bi_error; |
| bm_set_page_io_err(b->bm_pages[idx]); |
| /* Not identical to on disk version of it. |
| * Is BM_PAGE_IO_ERROR enough? */ |
| if (__ratelimit(&drbd_ratelimit_state)) |
| drbd_err(device, "IO ERROR %d on bitmap page idx %u\n", |
| bio->bi_error, idx); |
| } else { |
| bm_clear_page_io_err(b->bm_pages[idx]); |
| dynamic_drbd_dbg(device, "bitmap page idx %u completed\n", idx); |
| } |
| |
| bm_page_unlock_io(device, idx); |
| |
| if (ctx->flags & BM_AIO_COPY_PAGES) |
| mempool_free(bio->bi_io_vec[0].bv_page, drbd_md_io_page_pool); |
| |
| bio_put(bio); |
| |
| if (atomic_dec_and_test(&ctx->in_flight)) { |
| ctx->done = 1; |
| wake_up(&device->misc_wait); |
| kref_put(&ctx->kref, &drbd_bm_aio_ctx_destroy); |
| } |
| } |
| |
| static void bm_page_io_async(struct drbd_bm_aio_ctx *ctx, int page_nr) __must_hold(local) |
| { |
| struct bio *bio = bio_alloc_drbd(GFP_NOIO); |
| struct drbd_device *device = ctx->device; |
| struct drbd_bitmap *b = device->bitmap; |
| struct page *page; |
| unsigned int len; |
| unsigned int rw = (ctx->flags & BM_AIO_READ) ? READ : WRITE; |
| |
| sector_t on_disk_sector = |
| device->ldev->md.md_offset + device->ldev->md.bm_offset; |
| on_disk_sector += ((sector_t)page_nr) << (PAGE_SHIFT-9); |
| |
| /* this might happen with very small |
| * flexible external meta data device, |
| * or with PAGE_SIZE > 4k */ |
| len = min_t(unsigned int, PAGE_SIZE, |
| (drbd_md_last_sector(device->ldev) - on_disk_sector + 1)<<9); |
| |
| /* serialize IO on this page */ |
| bm_page_lock_io(device, page_nr); |
| /* before memcpy and submit, |
| * so it can be redirtied any time */ |
| bm_set_page_unchanged(b->bm_pages[page_nr]); |
| |
| if (ctx->flags & BM_AIO_COPY_PAGES) { |
| page = mempool_alloc(drbd_md_io_page_pool, __GFP_HIGHMEM|__GFP_WAIT); |
| copy_highpage(page, b->bm_pages[page_nr]); |
| bm_store_page_idx(page, page_nr); |
| } else |
| page = b->bm_pages[page_nr]; |
| bio->bi_bdev = device->ldev->md_bdev; |
| bio->bi_iter.bi_sector = on_disk_sector; |
| /* bio_add_page of a single page to an empty bio will always succeed, |
| * according to api. Do we want to assert that? */ |
| bio_add_page(bio, page, len, 0); |
| bio->bi_private = ctx; |
| bio->bi_end_io = drbd_bm_endio; |
| |
| if (drbd_insert_fault(device, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD)) { |
| bio->bi_rw |= rw; |
| bio_io_error(bio); |
| } else { |
| submit_bio(rw, bio); |
| /* this should not count as user activity and cause the |
| * resync to throttle -- see drbd_rs_should_slow_down(). */ |
| atomic_add(len >> 9, &device->rs_sect_ev); |
| } |
| } |
| |
| /* |
| * bm_rw: read/write the whole bitmap from/to its on disk location. |
| */ |
| static int bm_rw(struct drbd_device *device, const unsigned int flags, unsigned lazy_writeout_upper_idx) __must_hold(local) |
| { |
| struct drbd_bm_aio_ctx *ctx; |
| struct drbd_bitmap *b = device->bitmap; |
| int num_pages, i, count = 0; |
| unsigned long now; |
| char ppb[10]; |
| int err = 0; |
| |
| /* |
| * We are protected against bitmap disappearing/resizing by holding an |
| * ldev reference (caller must have called get_ldev()). |
| * For read/write, we are protected against changes to the bitmap by |
| * the bitmap lock (see drbd_bitmap_io). |
| * For lazy writeout, we don't care for ongoing changes to the bitmap, |
| * as we submit copies of pages anyways. |
| */ |
| |
| ctx = kmalloc(sizeof(struct drbd_bm_aio_ctx), GFP_NOIO); |
| if (!ctx) |
| return -ENOMEM; |
| |
| *ctx = (struct drbd_bm_aio_ctx) { |
| .device = device, |
| .start_jif = jiffies, |
| .in_flight = ATOMIC_INIT(1), |
| .done = 0, |
| .flags = flags, |
| .error = 0, |
| .kref = { ATOMIC_INIT(2) }, |
| }; |
| |
| if (!get_ldev_if_state(device, D_ATTACHING)) { /* put is in drbd_bm_aio_ctx_destroy() */ |
| drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in bm_rw()\n"); |
| kfree(ctx); |
| return -ENODEV; |
| } |
| /* Here D_ATTACHING is sufficient since drbd_bm_read() is called only from |
| drbd_adm_attach(), after device->ldev was assigned. */ |
| |
| if (0 == (ctx->flags & ~BM_AIO_READ)) |
| WARN_ON(!(BM_LOCKED_MASK & b->bm_flags)); |
| |
| spin_lock_irq(&device->resource->req_lock); |
| list_add_tail(&ctx->list, &device->pending_bitmap_io); |
| spin_unlock_irq(&device->resource->req_lock); |
| |
| num_pages = b->bm_number_of_pages; |
| |
| now = jiffies; |
| |
| /* let the layers below us try to merge these bios... */ |
| for (i = 0; i < num_pages; i++) { |
| /* ignore completely unchanged pages */ |
| if (lazy_writeout_upper_idx && i == lazy_writeout_upper_idx) |
| break; |
| if (!(flags & BM_AIO_READ)) { |
| if ((flags & BM_AIO_WRITE_HINTED) && |
| !test_and_clear_bit(BM_PAGE_HINT_WRITEOUT, |
| &page_private(b->bm_pages[i]))) |
| continue; |
| |
| if (!(flags & BM_AIO_WRITE_ALL_PAGES) && |
| bm_test_page_unchanged(b->bm_pages[i])) { |
| dynamic_drbd_dbg(device, "skipped bm write for idx %u\n", i); |
| continue; |
| } |
| /* during lazy writeout, |
| * ignore those pages not marked for lazy writeout. */ |
| if (lazy_writeout_upper_idx && |
| !bm_test_page_lazy_writeout(b->bm_pages[i])) { |
| dynamic_drbd_dbg(device, "skipped bm lazy write for idx %u\n", i); |
| continue; |
| } |
| } |
| atomic_inc(&ctx->in_flight); |
| bm_page_io_async(ctx, i); |
| ++count; |
| cond_resched(); |
| } |
| |
| /* |
| * We initialize ctx->in_flight to one to make sure drbd_bm_endio |
| * will not set ctx->done early, and decrement / test it here. If there |
| * are still some bios in flight, we need to wait for them here. |
| * If all IO is done already (or nothing had been submitted), there is |
| * no need to wait. Still, we need to put the kref associated with the |
| * "in_flight reached zero, all done" event. |
| */ |
| if (!atomic_dec_and_test(&ctx->in_flight)) |
| wait_until_done_or_force_detached(device, device->ldev, &ctx->done); |
| else |
| kref_put(&ctx->kref, &drbd_bm_aio_ctx_destroy); |
| |
| /* summary for global bitmap IO */ |
| if (flags == 0) |
| drbd_info(device, "bitmap %s of %u pages took %lu jiffies\n", |
| (flags & BM_AIO_READ) ? "READ" : "WRITE", |
| count, jiffies - now); |
| |
| if (ctx->error) { |
| drbd_alert(device, "we had at least one MD IO ERROR during bitmap IO\n"); |
| drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR); |
| err = -EIO; /* ctx->error ? */ |
| } |
| |
| if (atomic_read(&ctx->in_flight)) |
| err = -EIO; /* Disk timeout/force-detach during IO... */ |
| |
| now = jiffies; |
| if (flags & BM_AIO_READ) { |
| b->bm_set = bm_count_bits(b); |
| drbd_info(device, "recounting of set bits took additional %lu jiffies\n", |
| jiffies - now); |
| } |
| now = b->bm_set; |
| |
| if ((flags & ~BM_AIO_READ) == 0) |
| drbd_info(device, "%s (%lu bits) marked out-of-sync by on disk bit-map.\n", |
| ppsize(ppb, now << (BM_BLOCK_SHIFT-10)), now); |
| |
| kref_put(&ctx->kref, &drbd_bm_aio_ctx_destroy); |
| return err; |
| } |
| |
| /** |
| * drbd_bm_read() - Read the whole bitmap from its on disk location. |
| * @device: DRBD device. |
| */ |
| int drbd_bm_read(struct drbd_device *device) __must_hold(local) |
| { |
| return bm_rw(device, BM_AIO_READ, 0); |
| } |
| |
| /** |
| * drbd_bm_write() - Write the whole bitmap to its on disk location. |
| * @device: DRBD device. |
| * |
| * Will only write pages that have changed since last IO. |
| */ |
| int drbd_bm_write(struct drbd_device *device) __must_hold(local) |
| { |
| return bm_rw(device, 0, 0); |
| } |
| |
| /** |
| * drbd_bm_write_all() - Write the whole bitmap to its on disk location. |
| * @device: DRBD device. |
| * |
| * Will write all pages. |
| */ |
| int drbd_bm_write_all(struct drbd_device *device) __must_hold(local) |
| { |
| return bm_rw(device, BM_AIO_WRITE_ALL_PAGES, 0); |
| } |
| |
| /** |
| * drbd_bm_write_lazy() - Write bitmap pages 0 to @upper_idx-1, if they have changed. |
| * @device: DRBD device. |
| * @upper_idx: 0: write all changed pages; +ve: page index to stop scanning for changed pages |
| */ |
| int drbd_bm_write_lazy(struct drbd_device *device, unsigned upper_idx) __must_hold(local) |
| { |
| return bm_rw(device, BM_AIO_COPY_PAGES, upper_idx); |
| } |
| |
| /** |
| * drbd_bm_write_copy_pages() - Write the whole bitmap to its on disk location. |
| * @device: DRBD device. |
| * |
| * Will only write pages that have changed since last IO. |
| * In contrast to drbd_bm_write(), this will copy the bitmap pages |
| * to temporary writeout pages. It is intended to trigger a full write-out |
| * while still allowing the bitmap to change, for example if a resync or online |
| * verify is aborted due to a failed peer disk, while local IO continues, or |
| * pending resync acks are still being processed. |
| */ |
| int drbd_bm_write_copy_pages(struct drbd_device *device) __must_hold(local) |
| { |
| return bm_rw(device, BM_AIO_COPY_PAGES, 0); |
| } |
| |
| /** |
| * drbd_bm_write_hinted() - Write bitmap pages with "hint" marks, if they have changed. |
| * @device: DRBD device. |
| */ |
| int drbd_bm_write_hinted(struct drbd_device *device) __must_hold(local) |
| { |
| return bm_rw(device, BM_AIO_WRITE_HINTED | BM_AIO_COPY_PAGES, 0); |
| } |
| |
| /* NOTE |
| * find_first_bit returns int, we return unsigned long. |
| * For this to work on 32bit arch with bitnumbers > (1<<32), |
| * we'd need to return u64, and get a whole lot of other places |
| * fixed where we still use unsigned long. |
| * |
| * this returns a bit number, NOT a sector! |
| */ |
| static unsigned long __bm_find_next(struct drbd_device *device, unsigned long bm_fo, |
| const int find_zero_bit) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| unsigned long *p_addr; |
| unsigned long bit_offset; |
| unsigned i; |
| |
| |
| if (bm_fo > b->bm_bits) { |
| drbd_err(device, "bm_fo=%lu bm_bits=%lu\n", bm_fo, b->bm_bits); |
| bm_fo = DRBD_END_OF_BITMAP; |
| } else { |
| while (bm_fo < b->bm_bits) { |
| /* bit offset of the first bit in the page */ |
| bit_offset = bm_fo & ~BITS_PER_PAGE_MASK; |
| p_addr = __bm_map_pidx(b, bm_bit_to_page_idx(b, bm_fo)); |
| |
| if (find_zero_bit) |
| i = find_next_zero_bit_le(p_addr, |
| PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK); |
| else |
| i = find_next_bit_le(p_addr, |
| PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK); |
| |
| __bm_unmap(p_addr); |
| if (i < PAGE_SIZE*8) { |
| bm_fo = bit_offset + i; |
| if (bm_fo >= b->bm_bits) |
| break; |
| goto found; |
| } |
| bm_fo = bit_offset + PAGE_SIZE*8; |
| } |
| bm_fo = DRBD_END_OF_BITMAP; |
| } |
| found: |
| return bm_fo; |
| } |
| |
| static unsigned long bm_find_next(struct drbd_device *device, |
| unsigned long bm_fo, const int find_zero_bit) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| unsigned long i = DRBD_END_OF_BITMAP; |
| |
| if (!expect(b)) |
| return i; |
| if (!expect(b->bm_pages)) |
| return i; |
| |
| spin_lock_irq(&b->bm_lock); |
| if (BM_DONT_TEST & b->bm_flags) |
| bm_print_lock_info(device); |
| |
| i = __bm_find_next(device, bm_fo, find_zero_bit); |
| |
| spin_unlock_irq(&b->bm_lock); |
| return i; |
| } |
| |
| unsigned long drbd_bm_find_next(struct drbd_device *device, unsigned long bm_fo) |
| { |
| return bm_find_next(device, bm_fo, 0); |
| } |
| |
| #if 0 |
| /* not yet needed for anything. */ |
| unsigned long drbd_bm_find_next_zero(struct drbd_device *device, unsigned long bm_fo) |
| { |
| return bm_find_next(device, bm_fo, 1); |
| } |
| #endif |
| |
| /* does not spin_lock_irqsave. |
| * you must take drbd_bm_lock() first */ |
| unsigned long _drbd_bm_find_next(struct drbd_device *device, unsigned long bm_fo) |
| { |
| /* WARN_ON(!(BM_DONT_SET & device->b->bm_flags)); */ |
| return __bm_find_next(device, bm_fo, 0); |
| } |
| |
| unsigned long _drbd_bm_find_next_zero(struct drbd_device *device, unsigned long bm_fo) |
| { |
| /* WARN_ON(!(BM_DONT_SET & device->b->bm_flags)); */ |
| return __bm_find_next(device, bm_fo, 1); |
| } |
| |
| /* returns number of bits actually changed. |
| * for val != 0, we change 0 -> 1, return code positive |
| * for val == 0, we change 1 -> 0, return code negative |
| * wants bitnr, not sector. |
| * expected to be called for only a few bits (e - s about BITS_PER_LONG). |
| * Must hold bitmap lock already. */ |
| static int __bm_change_bits_to(struct drbd_device *device, const unsigned long s, |
| unsigned long e, int val) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| unsigned long *p_addr = NULL; |
| unsigned long bitnr; |
| unsigned int last_page_nr = -1U; |
| int c = 0; |
| int changed_total = 0; |
| |
| if (e >= b->bm_bits) { |
| drbd_err(device, "ASSERT FAILED: bit_s=%lu bit_e=%lu bm_bits=%lu\n", |
| s, e, b->bm_bits); |
| e = b->bm_bits ? b->bm_bits -1 : 0; |
| } |
| for (bitnr = s; bitnr <= e; bitnr++) { |
| unsigned int page_nr = bm_bit_to_page_idx(b, bitnr); |
| if (page_nr != last_page_nr) { |
| if (p_addr) |
| __bm_unmap(p_addr); |
| if (c < 0) |
| bm_set_page_lazy_writeout(b->bm_pages[last_page_nr]); |
| else if (c > 0) |
| bm_set_page_need_writeout(b->bm_pages[last_page_nr]); |
| changed_total += c; |
| c = 0; |
| p_addr = __bm_map_pidx(b, page_nr); |
| last_page_nr = page_nr; |
| } |
| if (val) |
| c += (0 == __test_and_set_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr)); |
| else |
| c -= (0 != __test_and_clear_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr)); |
| } |
| if (p_addr) |
| __bm_unmap(p_addr); |
| if (c < 0) |
| bm_set_page_lazy_writeout(b->bm_pages[last_page_nr]); |
| else if (c > 0) |
| bm_set_page_need_writeout(b->bm_pages[last_page_nr]); |
| changed_total += c; |
| b->bm_set += changed_total; |
| return changed_total; |
| } |
| |
| /* returns number of bits actually changed. |
| * for val != 0, we change 0 -> 1, return code positive |
| * for val == 0, we change 1 -> 0, return code negative |
| * wants bitnr, not sector */ |
| static int bm_change_bits_to(struct drbd_device *device, const unsigned long s, |
| const unsigned long e, int val) |
| { |
| unsigned long flags; |
| struct drbd_bitmap *b = device->bitmap; |
| int c = 0; |
| |
| if (!expect(b)) |
| return 1; |
| if (!expect(b->bm_pages)) |
| return 0; |
| |
| spin_lock_irqsave(&b->bm_lock, flags); |
| if ((val ? BM_DONT_SET : BM_DONT_CLEAR) & b->bm_flags) |
| bm_print_lock_info(device); |
| |
| c = __bm_change_bits_to(device, s, e, val); |
| |
| spin_unlock_irqrestore(&b->bm_lock, flags); |
| return c; |
| } |
| |
| /* returns number of bits changed 0 -> 1 */ |
| int drbd_bm_set_bits(struct drbd_device *device, const unsigned long s, const unsigned long e) |
| { |
| return bm_change_bits_to(device, s, e, 1); |
| } |
| |
| /* returns number of bits changed 1 -> 0 */ |
| int drbd_bm_clear_bits(struct drbd_device *device, const unsigned long s, const unsigned long e) |
| { |
| return -bm_change_bits_to(device, s, e, 0); |
| } |
| |
| /* sets all bits in full words, |
| * from first_word up to, but not including, last_word */ |
| static inline void bm_set_full_words_within_one_page(struct drbd_bitmap *b, |
| int page_nr, int first_word, int last_word) |
| { |
| int i; |
| int bits; |
| int changed = 0; |
| unsigned long *paddr = kmap_atomic(b->bm_pages[page_nr]); |
| for (i = first_word; i < last_word; i++) { |
| bits = hweight_long(paddr[i]); |
| paddr[i] = ~0UL; |
| changed += BITS_PER_LONG - bits; |
| } |
| kunmap_atomic(paddr); |
| if (changed) { |
| /* We only need lazy writeout, the information is still in the |
| * remote bitmap as well, and is reconstructed during the next |
| * bitmap exchange, if lost locally due to a crash. */ |
| bm_set_page_lazy_writeout(b->bm_pages[page_nr]); |
| b->bm_set += changed; |
| } |
| } |
| |
| /* Same thing as drbd_bm_set_bits, |
| * but more efficient for a large bit range. |
| * You must first drbd_bm_lock(). |
| * Can be called to set the whole bitmap in one go. |
| * Sets bits from s to e _inclusive_. */ |
| void _drbd_bm_set_bits(struct drbd_device *device, const unsigned long s, const unsigned long e) |
| { |
| /* First set_bit from the first bit (s) |
| * up to the next long boundary (sl), |
| * then assign full words up to the last long boundary (el), |
| * then set_bit up to and including the last bit (e). |
| * |
| * Do not use memset, because we must account for changes, |
| * so we need to loop over the words with hweight() anyways. |
| */ |
| struct drbd_bitmap *b = device->bitmap; |
| unsigned long sl = ALIGN(s,BITS_PER_LONG); |
| unsigned long el = (e+1) & ~((unsigned long)BITS_PER_LONG-1); |
| int first_page; |
| int last_page; |
| int page_nr; |
| int first_word; |
| int last_word; |
| |
| if (e - s <= 3*BITS_PER_LONG) { |
| /* don't bother; el and sl may even be wrong. */ |
| spin_lock_irq(&b->bm_lock); |
| __bm_change_bits_to(device, s, e, 1); |
| spin_unlock_irq(&b->bm_lock); |
| return; |
| } |
| |
| /* difference is large enough that we can trust sl and el */ |
| |
| spin_lock_irq(&b->bm_lock); |
| |
| /* bits filling the current long */ |
| if (sl) |
| __bm_change_bits_to(device, s, sl-1, 1); |
| |
| first_page = sl >> (3 + PAGE_SHIFT); |
| last_page = el >> (3 + PAGE_SHIFT); |
| |
| /* MLPP: modulo longs per page */ |
| /* LWPP: long words per page */ |
| first_word = MLPP(sl >> LN2_BPL); |
| last_word = LWPP; |
| |
| /* first and full pages, unless first page == last page */ |
| for (page_nr = first_page; page_nr < last_page; page_nr++) { |
| bm_set_full_words_within_one_page(device->bitmap, page_nr, first_word, last_word); |
| spin_unlock_irq(&b->bm_lock); |
| cond_resched(); |
| first_word = 0; |
| spin_lock_irq(&b->bm_lock); |
| } |
| /* last page (respectively only page, for first page == last page) */ |
| last_word = MLPP(el >> LN2_BPL); |
| |
| /* consider bitmap->bm_bits = 32768, bitmap->bm_number_of_pages = 1. (or multiples). |
| * ==> e = 32767, el = 32768, last_page = 2, |
| * and now last_word = 0. |
| * We do not want to touch last_page in this case, |
| * as we did not allocate it, it is not present in bitmap->bm_pages. |
| */ |
| if (last_word) |
| bm_set_full_words_within_one_page(device->bitmap, last_page, first_word, last_word); |
| |
| /* possibly trailing bits. |
| * example: (e & 63) == 63, el will be e+1. |
| * if that even was the very last bit, |
| * it would trigger an assert in __bm_change_bits_to() |
| */ |
| if (el <= e) |
| __bm_change_bits_to(device, el, e, 1); |
| spin_unlock_irq(&b->bm_lock); |
| } |
| |
| /* returns bit state |
| * wants bitnr, NOT sector. |
| * inherently racy... area needs to be locked by means of {al,rs}_lru |
| * 1 ... bit set |
| * 0 ... bit not set |
| * -1 ... first out of bounds access, stop testing for bits! |
| */ |
| int drbd_bm_test_bit(struct drbd_device *device, const unsigned long bitnr) |
| { |
| unsigned long flags; |
| struct drbd_bitmap *b = device->bitmap; |
| unsigned long *p_addr; |
| int i; |
| |
| if (!expect(b)) |
| return 0; |
| if (!expect(b->bm_pages)) |
| return 0; |
| |
| spin_lock_irqsave(&b->bm_lock, flags); |
| if (BM_DONT_TEST & b->bm_flags) |
| bm_print_lock_info(device); |
| if (bitnr < b->bm_bits) { |
| p_addr = bm_map_pidx(b, bm_bit_to_page_idx(b, bitnr)); |
| i = test_bit_le(bitnr & BITS_PER_PAGE_MASK, p_addr) ? 1 : 0; |
| bm_unmap(p_addr); |
| } else if (bitnr == b->bm_bits) { |
| i = -1; |
| } else { /* (bitnr > b->bm_bits) */ |
| drbd_err(device, "bitnr=%lu > bm_bits=%lu\n", bitnr, b->bm_bits); |
| i = 0; |
| } |
| |
| spin_unlock_irqrestore(&b->bm_lock, flags); |
| return i; |
| } |
| |
| /* returns number of bits set in the range [s, e] */ |
| int drbd_bm_count_bits(struct drbd_device *device, const unsigned long s, const unsigned long e) |
| { |
| unsigned long flags; |
| struct drbd_bitmap *b = device->bitmap; |
| unsigned long *p_addr = NULL; |
| unsigned long bitnr; |
| unsigned int page_nr = -1U; |
| int c = 0; |
| |
| /* If this is called without a bitmap, that is a bug. But just to be |
| * robust in case we screwed up elsewhere, in that case pretend there |
| * was one dirty bit in the requested area, so we won't try to do a |
| * local read there (no bitmap probably implies no disk) */ |
| if (!expect(b)) |
| return 1; |
| if (!expect(b->bm_pages)) |
| return 1; |
| |
| spin_lock_irqsave(&b->bm_lock, flags); |
| if (BM_DONT_TEST & b->bm_flags) |
| bm_print_lock_info(device); |
| for (bitnr = s; bitnr <= e; bitnr++) { |
| unsigned int idx = bm_bit_to_page_idx(b, bitnr); |
| if (page_nr != idx) { |
| page_nr = idx; |
| if (p_addr) |
| bm_unmap(p_addr); |
| p_addr = bm_map_pidx(b, idx); |
| } |
| if (expect(bitnr < b->bm_bits)) |
| c += (0 != test_bit_le(bitnr - (page_nr << (PAGE_SHIFT+3)), p_addr)); |
| else |
| drbd_err(device, "bitnr=%lu bm_bits=%lu\n", bitnr, b->bm_bits); |
| } |
| if (p_addr) |
| bm_unmap(p_addr); |
| spin_unlock_irqrestore(&b->bm_lock, flags); |
| return c; |
| } |
| |
| |
| /* inherently racy... |
| * return value may be already out-of-date when this function returns. |
| * but the general usage is that this is only use during a cstate when bits are |
| * only cleared, not set, and typically only care for the case when the return |
| * value is zero, or we already "locked" this "bitmap extent" by other means. |
| * |
| * enr is bm-extent number, since we chose to name one sector (512 bytes) |
| * worth of the bitmap a "bitmap extent". |
| * |
| * TODO |
| * I think since we use it like a reference count, we should use the real |
| * reference count of some bitmap extent element from some lru instead... |
| * |
| */ |
| int drbd_bm_e_weight(struct drbd_device *device, unsigned long enr) |
| { |
| struct drbd_bitmap *b = device->bitmap; |
| int count, s, e; |
| unsigned long flags; |
| unsigned long *p_addr, *bm; |
| |
| if (!expect(b)) |
| return 0; |
| if (!expect(b->bm_pages)) |
| return 0; |
| |
| spin_lock_irqsave(&b->bm_lock, flags); |
| if (BM_DONT_TEST & b->bm_flags) |
| bm_print_lock_info(device); |
| |
| s = S2W(enr); |
| e = min((size_t)S2W(enr+1), b->bm_words); |
| count = 0; |
| if (s < b->bm_words) { |
| int n = e-s; |
| p_addr = bm_map_pidx(b, bm_word_to_page_idx(b, s)); |
| bm = p_addr + MLPP(s); |
| while (n--) |
| count += hweight_long(*bm++); |
| bm_unmap(p_addr); |
| } else { |
| drbd_err(device, "start offset (%d) too large in drbd_bm_e_weight\n", s); |
| } |
| spin_unlock_irqrestore(&b->bm_lock, flags); |
| return count; |
| } |