diff options
Diffstat (limited to 'drivers/block/drbd/drbd_bitmap.c')
| -rw-r--r-- | drivers/block/drbd/drbd_bitmap.c | 1327 |
1 files changed, 1327 insertions, 0 deletions
diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c new file mode 100644 index 000000000000..b61057e77882 --- /dev/null +++ b/drivers/block/drbd/drbd_bitmap.c @@ -0,0 +1,1327 @@ +/* + 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. + */ + +#include <linux/bitops.h> +#include <linux/vmalloc.h> +#include <linux/string.h> +#include <linux/drbd.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". + + * Note that since find_first_bit returns int, at the current granularity of + * the bitmap (4KB per byte), this implementation "only" supports up to + * 1<<(32+12) == 16 TB... + */ + +/* + * 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; + /* WARNING unsigned long bm_*: + * 32bit number of bit offset is just enough for 512 MB bitmap. + * it will blow up if we make the bitmap bigger... + * not that it makes much sense to have a bitmap that large, + * rather change the granularity to 16k or 64k or something. + * (that implies other problems, however...) + */ + 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 semaphore bm_change; /* serializes resize operations */ + + atomic_t bm_async_io; + wait_queue_head_t bm_io_wait; + + unsigned long bm_flags; + + /* debugging aid, in case we are still racy somewhere */ + char *bm_why; + struct task_struct *bm_task; +}; + +/* definition of bits in bm_flags */ +#define BM_LOCKED 0 +#define BM_MD_IO_ERROR 1 +#define BM_P_VMALLOCED 2 + +static int bm_is_locked(struct drbd_bitmap *b) +{ + return test_bit(BM_LOCKED, &b->bm_flags); +} + +#define bm_print_lock_info(m) __bm_print_lock_info(m, __func__) +static void __bm_print_lock_info(struct drbd_conf *mdev, const char *func) +{ + struct drbd_bitmap *b = mdev->bitmap; + if (!__ratelimit(&drbd_ratelimit_state)) + return; + dev_err(DEV, "FIXME %s in %s, bitmap locked for '%s' by %s\n", + current == mdev->receiver.task ? "receiver" : + current == mdev->asender.task ? "asender" : + current == mdev->worker.task ? "worker" : current->comm, + func, b->bm_why ?: "?", + b->bm_task == mdev->receiver.task ? "receiver" : + b->bm_task == mdev->asender.task ? "asender" : + b->bm_task == mdev->worker.task ? "worker" : "?"); +} + +void drbd_bm_lock(struct drbd_conf *mdev, char *why) +{ + struct drbd_bitmap *b = mdev->bitmap; + int trylock_failed; + + if (!b) { + dev_err(DEV, "FIXME no bitmap in drbd_bm_lock!?\n"); + return; + } + + trylock_failed = down_trylock(&b->bm_change); + + if (trylock_failed) { + dev_warn(DEV, "%s going to '%s' but bitmap already locked for '%s' by %s\n", + current == mdev->receiver.task ? "receiver" : + current == mdev->asender.task ? "asender" : + current == mdev->worker.task ? "worker" : current->comm, + why, b->bm_why ?: "?", + b->bm_task == mdev->receiver.task ? "receiver" : + b->bm_task == mdev->asender.task ? "asender" : + b->bm_task == mdev->worker.task ? "worker" : "?"); + down(&b->bm_change); + } + if (__test_and_set_bit(BM_LOCKED, &b->bm_flags)) + dev_err(DEV, "FIXME bitmap already locked in bm_lock\n"); + + b->bm_why = why; + b->bm_task = current; +} + +void drbd_bm_unlock(struct drbd_conf *mdev) +{ + struct drbd_bitmap *b = mdev->bitmap; + if (!b) { + dev_err(DEV, "FIXME no bitmap in drbd_bm_unlock!?\n"); + return; + } + + if (!__test_and_clear_bit(BM_LOCKED, &mdev->bitmap->bm_flags)) + dev_err(DEV, "FIXME bitmap not locked in bm_unlock\n"); + + b->bm_why = NULL; + b->bm_task = NULL; + up(&b->bm_change); +} + +/* word offset to long pointer */ +static unsigned long *__bm_map_paddr(struct drbd_bitmap *b, unsigned long offset, const enum km_type km) +{ + struct page *page; + unsigned long page_nr; + + /* page_nr = (word*sizeof(long)) >> PAGE_SHIFT; */ + page_nr = offset >> (PAGE_SHIFT - LN2_BPL + 3); + BUG_ON(page_nr >= b->bm_number_of_pages); + page = b->bm_pages[page_nr]; + + return (unsigned long *) kmap_atomic(page, km); +} + +static unsigned long * bm_map_paddr(struct drbd_bitmap *b, unsigned long offset) +{ + return __bm_map_paddr(b, offset, KM_IRQ1); +} + +static void __bm_unmap(unsigned long *p_addr, const enum km_type km) +{ + kunmap_atomic(p_addr, km); +}; + +static void bm_unmap(unsigned long *p_addr) +{ + return __bm_unmap(p_addr, KM_IRQ1); +} + +/* 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 optimze 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_conf*, but for the debug macros I like to have the mdev 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]) { + printk(KERN_ALERT "drbd: 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_KERNEL is ok, as this is done when a lower level disk is + * "attached" to the drbd. Context is receiver thread or cqueue + * thread. As we have no disk yet, we are not in the IO path, + * not even the IO path of the peer. */ + bytes = sizeof(struct page *)*want; + new_pages = kmalloc(bytes, GFP_KERNEL); + if (!new_pages) { + new_pages = vmalloc(bytes); + if (!new_pages) + return NULL; + vmalloced = 1; + } + + memset(new_pages, 0, bytes); + if (want >= have) { + for (i = 0; i < have; i++) + new_pages[i] = old_pages[i]; + for (; i < want; i++) { + page = alloc_page(GFP_HIGHUSER); + if (!page) { + bm_free_pages(new_pages + have, i - have); + bm_vk_free(new_pages, vmalloced); + return NULL; + } + 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) + set_bit(BM_P_VMALLOCED, &b->bm_flags); + else + clear_bit(BM_P_VMALLOCED, &b->bm_flags); + + return new_pages; +} + +/* + * called on driver init only. TODO call when a device is created. + * allocates the drbd_bitmap, and stores it in mdev->bitmap. + */ +int drbd_bm_init(struct drbd_conf *mdev) +{ + struct drbd_bitmap *b = mdev->bitmap; + WARN_ON(b != NULL); + b = kzalloc(sizeof(struct drbd_bitmap), GFP_KERNEL); + if (!b) + return -ENOMEM; + spin_lock_init(&b->bm_lock); + init_MUTEX(&b->bm_change); + init_waitqueue_head(&b->bm_io_wait); + + mdev->bitmap = b; + + return 0; +} + +sector_t drbd_bm_capacity(struct drbd_conf *mdev) +{ + ERR_IF(!mdev->bitmap) return 0; + return mdev->bitmap->bm_dev_capacity; +} + +/* called on driver unload. TODO: call when a device is destroyed. + */ +void drbd_bm_cleanup(struct drbd_conf *mdev) +{ + ERR_IF (!mdev->bitmap) return; + bm_free_pages(mdev->bitmap->bm_pages, mdev->bitmap->bm_number_of_pages); + bm_vk_free(mdev->bitmap->bm_pages, test_bit(BM_P_VMALLOCED, &mdev->bitmap->bm_flags)); + kfree(mdev->bitmap); + mdev->bitmap = NULL; +} + +/* + * since (b->bm_bits % BITS_PER_LONG) != 0, + * this masks out the remaining bits. + * Returns the number of bits cleared. + */ +static int bm_clear_surplus(struct drbd_bitmap *b) +{ + const unsigned long mask = (1UL << (b->bm_bits & (BITS_PER_LONG-1))) - 1; + size_t w = b->bm_bits >> LN2_BPL; + int cleared = 0; + unsigned long *p_addr, *bm; + + p_addr = bm_map_paddr(b, w); + bm = p_addr + MLPP(w); + if (w < b->bm_words) { + cleared = hweight_long(*bm & ~mask); + *bm &= mask; + w++; bm++; + } + + if (w < b->bm_words) { + cleared += hweight_long(*bm); + *bm = 0; + } + bm_unmap(p_addr); + return cleared; +} + +static void bm_set_surplus(struct drbd_bitmap *b) +{ + const unsigned long mask = (1UL << (b->bm_bits & (BITS_PER_LONG-1))) - 1; + size_t w = b->bm_bits >> LN2_BPL; + unsigned long *p_addr, *bm; + + p_addr = bm_map_paddr(b, w); + bm = p_addr + MLPP(w); + if (w < b->bm_words) { + *bm |= ~mask; + bm++; w++; + } + + if (w < b->bm_words) { + *bm = ~(0UL); + } + bm_unmap(p_addr); +} + +static unsigned long __bm_count_bits(struct drbd_bitmap *b, const int swap_endian) +{ + unsigned long *p_addr, *bm, offset = 0; + unsigned long bits = 0; + unsigned long i, do_now; + + while (offset < b->bm_words) { + i = do_now = min_t(size_t, b->bm_words-offset, LWPP); + p_addr = __bm_map_paddr(b, offset, KM_USER0); + bm = p_addr + MLPP(offset); + while (i--) { +#ifndef __LITTLE_ENDIAN + if (swap_endian) + *bm = lel_to_cpu(*bm); +#endif + bits += hweight_long(*bm++); + } + __bm_unmap(p_addr, KM_USER0); + offset += do_now; + cond_resched(); + } + + return bits; +} + +static unsigned long bm_count_bits(struct drbd_bitmap *b) +{ + return __bm_count_bits(b, 0); +} + +static unsigned long bm_count_bits_swap_endian(struct drbd_bitmap *b) +{ + return __bm_count_bits(b, 1); +} + +/* 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; + size_t do_now, end; + +#define BM_SECTORS_PER_BIT (BM_BLOCK_SIZE/512) + + end = offset + len; + + if (end > b->bm_words) { + printk(KERN_ALERT "drbd: bm_memset end > bm_words\n"); + return; + } + + while (offset < end) { + do_now = min_t(size_t, ALIGN(offset + 1, LWPP), end) - offset; + p_addr = bm_map_paddr(b, offset); + bm = p_addr + MLPP(offset); + if (bm+do_now > p_addr + LWPP) { + printk(KERN_ALERT "drbd: BUG BUG BUG! p_addr:%p bm:%p do_now:%d\n", + p_addr, bm, (int)do_now); + break; /* breaks to after catch_oob_access_end() only! */ + } + memset(bm, c, do_now * sizeof(long)); + bm_unmap(p_addr); + offset += do_now; + } +} + +/* + * 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_conf *mdev, sector_t capacity) +{ + struct drbd_bitmap *b = mdev->bitmap; + unsigned long bits, words, owords, obits, *p_addr, *bm; + unsigned long want, have, onpages; /* number of pages */ + struct page **npages, **opages = NULL; + int err = 0, growing; + int opages_vmalloced; + + ERR_IF(!b) return -ENOMEM; + + drbd_bm_lock(mdev, "resize"); + + dev_info(DEV, "drbd_bm_resize called with capacity == %llu\n", + (unsigned long long)capacity); + + if (capacity == b->bm_dev_capacity) + goto out; + + opages_vmalloced = test_bit(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(mdev)) { + D_ASSERT((u64)bits <= (((u64)mdev->ldev->md.md_size_sect-MD_BM_OFFSET) << 12)); + put_ldev(mdev); + } + + /* one extra long to catch off by one errors */ + want = ALIGN((words+1)*sizeof(long), PAGE_SIZE) >> PAGE_SHIFT; + have = b->bm_number_of_pages; + if (want == have) { + D_ASSERT(b->bm_pages != NULL); + npages = b->bm_pages; + } else { + if (FAULT_ACTIVE(mdev, 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) + 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) { + bm_memset(b, owords, 0xff, words-owords); + b->bm_set += bits - obits; + } + + if (want < have) { + /* implicit: (opages != NULL) && (opages != npages) */ + bm_free_pages(opages + want, have - want); + } + + p_addr = bm_map_paddr(b, words); + bm = p_addr + MLPP(words); + *bm = DRBD_MAGIC; + bm_unmap(p_addr); + + (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); + dev_info(DEV, "resync bitmap: bits=%lu words=%lu\n", bits, words); + + out: + drbd_bm_unlock(mdev); + 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 ? + */ +static unsigned long _drbd_bm_total_weight(struct drbd_conf *mdev) +{ + struct drbd_bitmap *b = mdev->bitmap; + unsigned long s; + unsigned long flags; + + ERR_IF(!b) return 0; + ERR_IF(!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_conf *mdev) +{ + unsigned long s; + /* if I don't have a disk, I don't know about out-of-sync status */ + if (!get_ldev_if_state(mdev, D_NEGOTIATING)) + return 0; + s = _drbd_bm_total_weight(mdev); + put_ldev(mdev); + return s; +} + +size_t drbd_bm_words(struct drbd_conf *mdev) +{ + struct drbd_bitmap *b = mdev->bitmap; + ERR_IF(!b) return 0; + ERR_IF(!b->bm_pages) return 0; + + return b->bm_words; +} + +unsigned long drbd_bm_bits(struct drbd_conf *mdev) +{ + struct drbd_bitmap *b = mdev->bitmap; + ERR_IF(!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_conf *mdev, size_t offset, size_t number, + unsigned long *buffer) +{ + struct drbd_bitmap *b = mdev->bitmap; + unsigned long *p_addr, *bm; + unsigned long word, bits; + size_t end, do_now; + + end = offset + number; + + ERR_IF(!b) return; + ERR_IF(!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; + p_addr = bm_map_paddr(b, offset); + bm = p_addr + MLPP(offset); + offset += do_now; + while (do_now--) { + bits = hweight_long(*bm); + word = *bm | lel_to_cpu(*buffer++); + *bm++ = word; + b->bm_set += hweight_long(word) - bits; + } + bm_unmap(p_addr); + } + /* 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_conf *mdev, size_t offset, size_t number, + unsigned long *buffer) +{ + struct drbd_bitmap *b = mdev->bitmap; + unsigned long *p_addr, *bm; + size_t end, do_now; + + end = offset + number; + + ERR_IF(!b) return; + ERR_IF(!b->bm_pages) return; + + spin_lock_irq(&b->bm_lock); + if ((offset >= b->bm_words) || + (end > b->bm_words) || + (number <= 0)) + dev_err(DEV, "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_paddr(b, offset); + bm = p_addr + MLPP(offset); + offset += do_now; + while (do_now--) + *buffer++ = cpu_to_lel(*bm++); + bm_unmap(p_addr); + } + } + spin_unlock_irq(&b->bm_lock); +} + +/* set all bits in the bitmap */ +void drbd_bm_set_all(struct drbd_conf *mdev) +{ + struct drbd_bitmap *b = mdev->bitmap; + ERR_IF(!b) return; + ERR_IF(!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_conf *mdev) +{ + struct drbd_bitmap *b = mdev->bitmap; + ERR_IF(!b) return; + ERR_IF(!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 bm_async_io_complete(struct bio *bio, int error) +{ + struct drbd_bitmap *b = bio->bi_private; + int uptodate = bio_flagged(bio, BIO_UPTODATE); + + + /* strange behavior of some lower level drivers... + * fail the request by clearing the uptodate flag, + * but do not return any error?! + * do we want to WARN() on this? */ + if (!error && !uptodate) + error = -EIO; + + if (error) { + /* doh. what now? + * for now, set all bits, and flag MD_IO_ERROR */ + __set_bit(BM_MD_IO_ERROR, &b->bm_flags); + } + if (atomic_dec_and_test(&b->bm_async_io)) + wake_up(&b->bm_io_wait); + + bio_put(bio); +} + +static void bm_page_io_async(struct drbd_conf *mdev, struct drbd_bitmap *b, int page_nr, int rw) __must_hold(local) +{ + /* we are process context. we always get a bio */ + struct bio *bio = bio_alloc(GFP_KERNEL, 1); + unsigned int len; + sector_t on_disk_sector = + mdev->ldev->md.md_offset + mdev->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 */ + len = min_t(unsigned int, PAGE_SIZE, + (drbd_md_last_sector(mdev->ldev) - on_disk_sector + 1)<<9); + + bio->bi_bdev = mdev->ldev->md_bdev; + bio->bi_sector = on_disk_sector; + bio_add_page(bio, b->bm_pages[page_nr], len, 0); + bio->bi_private = b; + bio->bi_end_io = bm_async_io_complete; + + if (FAULT_ACTIVE(mdev, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD)) { + bio->bi_rw |= rw; + bio_endio(bio, -EIO); + } else { + submit_bio(rw, bio); + } +} + +# if defined(__LITTLE_ENDIAN) + /* nothing to do, on disk == in memory */ +# define bm_cpu_to_lel(x) ((void)0) +# else +void bm_cpu_to_lel(struct drbd_bitmap *b) +{ + /* need to cpu_to_lel all the pages ... + * this may be optimized by using + * cpu_to_lel(-1) == -1 and cpu_to_lel(0) == 0; + * the following is still not optimal, but better than nothing */ + unsigned int i; + unsigned long *p_addr, *bm; + if (b->bm_set == 0) { + /* no page at all; avoid swap if all is 0 */ + i = b->bm_number_of_pages; + } else if (b->bm_set == b->bm_bits) { + /* only the last page */ + i = b->bm_number_of_pages - 1; + } else { + /* all pages */ + i = 0; + } + for (; i < b->bm_number_of_pages; i++) { + p_addr = kmap_atomic(b->bm_pages[i], KM_USER0); + for (bm = p_addr; bm < p_addr + PAGE_SIZE/sizeof(long); bm++) + *bm = cpu_to_lel(*bm); + kunmap_atomic(p_addr, KM_USER0); + } +} +# endif +/* lel_to_cpu == cpu_to_lel */ +# define bm_lel_to_cpu(x) bm_cpu_to_lel(x) + +/* + * bm_rw: read/write the whole bitmap from/to its on disk location. + */ +static int bm_rw(struct drbd_conf *mdev, int rw) __must_hold(local) +{ + struct drbd_bitmap *b = mdev->bitmap; + /* sector_t sector; */ + int bm_words, num_pages, i; + unsigned long now; + char ppb[10]; + int err = 0; + + WARN_ON(!bm_is_locked(b)); + + /* no spinlock here, the drbd_bm_lock should be enough! */ + + bm_words = drbd_bm_words(mdev); + num_pages = (bm_words*sizeof(long) + PAGE_SIZE-1) >> PAGE_SHIFT; + + /* on disk bitmap is little endian */ + if (rw == WRITE) + bm_cpu_to_lel(b); + + now = jiffies; + atomic_set(&b->bm_async_io, num_pages); + __clear_bit(BM_MD_IO_ERROR, &b->bm_flags); + + /* let the layers below us try to merge these bios... */ + for (i = 0; i < num_pages; i++) + bm_page_io_async(mdev, b, i, rw); + + drbd_blk_run_queue(bdev_get_queue(mdev->ldev->md_bdev)); + wait_event(b->bm_io_wait, atomic_read(&b->bm_async_io) == 0); + + if (test_bit(BM_MD_IO_ERROR, &b->bm_flags)) { + dev_alert(DEV, "we had at least one MD IO ERROR during bitmap IO\n"); + drbd_chk_io_error(mdev, 1, TRUE); + err = -EIO; + } + + now = jiffies; + if (rw == WRITE) { + /* swap back endianness */ + bm_lel_to_cpu(b); + /* flush bitmap to stable storage */ + drbd_md_flush(mdev); + } else /* rw == READ */ { + /* just read, if necessary adjust endianness */ + b->bm_set = bm_count_bits_swap_endian(b); + dev_info(DEV, "recounting of set bits took additional %lu jiffies\n", + jiffies - now); + } + now = b->bm_set; + + dev_info(DEV, "%s (%lu bits) marked out-of-sync by on disk bit-map.\n", + ppsize(ppb, now << (BM_BLOCK_SHIFT-10)), now); + + return err; +} + +/** + * drbd_bm_read() - Read the whole bitmap from its on disk location. + * @mdev: DRBD device. + */ +int drbd_bm_read(struct drbd_conf *mdev) __must_hold(local) +{ + return bm_rw(mdev, READ); +} + +/** + * drbd_bm_write() - Write the whole bitmap to its on disk location. + * @mdev: DRBD device. + */ +int drbd_bm_write(struct drbd_conf *mdev) __must_hold(local) +{ + return bm_rw(mdev, WRITE); +} + +/** + * drbd_bm_write_sect: Writes a 512 (MD_SECTOR_SIZE) byte piece of the bitmap + * @mdev: DRBD device. + * @enr: Extent number in the resync lru (happens to be sector offset) + * + * The BM_EXT_SIZE is on purpose exactly the amount of the bitmap covered + * by a single sector write. Therefore enr == sector offset from the + * start of the bitmap. + */ +int drbd_bm_write_sect(struct drbd_conf *mdev, unsigned long enr) __must_hold(local) +{ + sector_t on_disk_sector = enr + mdev->ldev->md.md_offset + + mdev->ldev->md.bm_offset; + int bm_words, num_words, offset; + int err = 0; + + mutex_lock(&mdev->md_io_mutex); + bm_words = drbd_bm_words(mdev); + offset = S2W(enr); /* word offset into bitmap */ + num_words = min(S2W(1), bm_words - offset); + if (num_words < S2W(1)) + memset(page_address(mdev->md_io_page), 0, MD_SECTOR_SIZE); + drbd_bm_get_lel(mdev, offset, num_words, + page_address(mdev->md_io_page)); + if (!drbd_md_sync_page_io(mdev, mdev->ldev, on_disk_sector, WRITE)) { + int i; + err = -EIO; + dev_err(DEV, "IO ERROR writing bitmap sector %lu " + "(meta-disk sector %llus)\n", + enr, (unsigned long long)on_disk_sector); + drbd_chk_io_error(mdev, 1, TRUE); + for (i = 0; i < AL_EXT_PER_BM_SECT; i++) + drbd_bm_ALe_set_all(mdev, enr*AL_EXT_PER_BM_SECT+i); + } + mdev->bm_writ_cnt++; + mutex_unlock(&mdev->md_io_mutex); + return err; +} + +/* NOTE + * find_first_bit returns int, we return unsigned long. + * should not make much difference anyways, but ... + * + * this returns a bit number, NOT a sector! + */ +#define BPP_MASK ((1UL << (PAGE_SHIFT+3)) - 1) +static unsigned long __bm_find_next(struct drbd_conf *mdev, unsigned long bm_fo, + const int find_zero_bit, const enum km_type km) +{ + struct drbd_bitmap *b = mdev->bitmap; + unsigned long i = -1UL; + unsigned long *p_addr; + unsigned long bit_offset; /* bit offset of the mapped page. */ + + if (bm_fo > b->bm_bits) { + dev_err(DEV, "bm_fo=%lu bm_bits=%lu\n", bm_fo, b->bm_bits); + } else { + while (bm_fo < b->bm_bits) { + unsigned long offset; + bit_offset = bm_fo & ~BPP_MASK; /* bit offset of the page */ + offset = bit_offset >> LN2_BPL; /* word offset of the page */ + p_addr = __bm_map_paddr(b, offset, km); + + if (find_zero_bit) + i = find_next_zero_bit(p_addr, PAGE_SIZE*8, bm_fo & BPP_MASK); + else + i = find_next_bit(p_addr, PAGE_SIZE*8, bm_fo & BPP_MASK); + + __bm_unmap(p_addr, km); + if (i < PAGE_SIZE*8) { + i = bit_offset + i; + if (i >= b->bm_bits) + break; + goto found; + } + bm_fo = bit_offset + PAGE_SIZE*8; + } + i = -1UL; + } + found: + return i; +} + +static unsigned long bm_find_next(struct drbd_conf *mdev, + unsigned long bm_fo, const int find_zero_bit) +{ + struct drbd_bitmap *b = mdev->bitmap; + unsigned long i = -1UL; + + ERR_IF(!b) return i; + ERR_IF(!b->bm_pages) return i; + + spin_lock_irq(&b->bm_lock); + if (bm_is_locked(b)) + bm_print_lock_info(mdev); + + i = __bm_find_next(mdev, bm_fo, find_zero_bit, KM_IRQ1); + + spin_unlock_irq(&b->bm_lock); + return i; +} + +unsigned long drbd_bm_find_next(struct drbd_conf *mdev, unsigned long bm_fo) +{ + return bm_find_next(mdev, bm_fo, 0); +} + +#if 0 +/* not yet needed for anything. */ +unsigned long drbd_bm_find_next_zero(struct drbd_conf *mdev, unsigned long bm_fo) +{ + return bm_find_next(mdev, bm_fo, 1); +} +#endif + +/* does not spin_lock_irqsave. + * you must take drbd_bm_lock() first */ +unsigned long _drbd_bm_find_next(struct drbd_conf *mdev, unsigned long bm_fo) +{ + /* WARN_ON(!bm_is_locked(mdev)); */ + return __bm_find_next(mdev, bm_fo, 0, KM_USER1); +} + +unsigned long _drbd_bm_find_next_zero(struct drbd_conf *mdev, unsigned long bm_fo) +{ + /* WARN_ON(!bm_is_locked(mdev)); */ + return __bm_find_next(mdev, bm_fo, 1, KM_USER1); +} + +/* 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. */ +int __bm_change_bits_to(struct drbd_conf *mdev, const unsigned long s, + unsigned long e, int val, const enum km_type km) +{ + struct drbd_bitmap *b = mdev->bitmap; + unsigned long *p_addr = NULL; + unsigned long bitnr; + unsigned long last_page_nr = -1UL; + int c = 0; + + if (e >= b->bm_bits) { + dev_err(DEV, "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 long offset = bitnr>>LN2_BPL; + unsigned long page_nr = offset >> (PAGE_SHIFT - LN2_BPL + 3); + if (page_nr != last_page_nr) { + if (p_addr) + __bm_unmap(p_addr, km); + p_addr = __bm_map_paddr(b, offset, km); + last_page_nr = page_nr; + } + if (val) + c += (0 == __test_and_set_bit(bitnr & BPP_MASK, p_addr)); + else + c -= (0 != __test_and_clear_bit(bitnr & BPP_MASK, p_addr)); + } + if (p_addr) + __bm_unmap(p_addr, km); + b->bm_set += c; + return c; +} + +/* 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 */ +int bm_change_bits_to(struct drbd_conf *mdev, const unsigned long s, + const unsigned long e, int val) +{ + unsigned long flags; + struct drbd_bitmap *b = mdev->bitmap; + int c = 0; + + ERR_IF(!b) return 1; + ERR_IF(!b->bm_pages) return 0; + + spin_lock_irqsave(&b->bm_lock, flags); + if (bm_is_locked(b)) + bm_print_lock_info(mdev); + + c = __bm_change_bits_to(mdev, s, e, val, KM_IRQ1); + + spin_unlock_irqrestore(&b->bm_lock, flags); + return c; +} + +/* returns number of bits changed 0 -> 1 */ +int drbd_bm_set_bits(struct drbd_conf *mdev, const unsigned long s, const unsigned long e) +{ + return bm_change_bits_to(mdev, s, e, 1); +} + +/* returns number of bits changed 1 -> 0 */ +int drbd_bm_clear_bits(struct drbd_conf *mdev, const unsigned long s, const unsigned long e) +{ + return -bm_change_bits_to(mdev, 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; + unsigned long *paddr = kmap_atomic(b->bm_pages[page_nr], KM_USER0); + for (i = first_word; i < last_word; i++) { + bits = hweight_long(paddr[i]); + paddr[i] = ~0UL; + b->bm_set += BITS_PER_LONG - bits; + } + kunmap_atomic(paddr, KM_USER0); +} + +/* Same thing as drbd_bm_set_bits, but without taking the spin_lock_irqsave. + * 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_conf *mdev, 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. + */ + 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. */ + __bm_change_bits_to(mdev, s, e, 1, KM_USER0); + return; + } + + /* difference is large enough that we can trust sl and el */ + + /* bits filling the current long */ + if (sl) + __bm_change_bits_to(mdev, s, sl-1, 1, KM_USER0); + + 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(mdev->bitmap, page_nr, first_word, last_word); + cond_resched(); + first_word = 0; + } + + /* last page (respectively only page, for first page == last page) */ + last_word = MLPP(el >> LN2_BPL); + bm_set_full_words_within_one_page(mdev->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(mdev, el, e, 1, KM_USER0); +} + +/* 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_conf *mdev, const unsigned long bitnr) +{ + unsigned long flags; + struct drbd_bitmap *b = mdev->bitmap; + unsigned long *p_addr; + int i; + + ERR_IF(!b) return 0; + ERR_IF(!b->bm_pages) return 0; + + spin_lock_irqsave(&b->bm_lock, flags); + if (bm_is_locked(b)) + bm_print_lock_info(mdev); + if (bitnr < b->bm_bits) { + unsigned long offset = bitnr>>LN2_BPL; + p_addr = bm_map_paddr(b, offset); + i = test_bit(bitnr & BPP_MASK, p_addr) ? 1 : 0; + bm_unmap(p_addr); + } else if (bitnr == b->bm_bits) { + i = -1; + } else { /* (bitnr > b->bm_bits) */ + dev_err(DEV, "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_conf *mdev, const unsigned long s, const unsigned long e) +{ + unsigned long flags; + struct drbd_bitmap *b = mdev->bitmap; + unsigned long *p_addr = NULL, page_nr = -1; + unsigned long bitnr; + int c = 0; + size_t w; + + /* 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) */ + ERR_IF(!b) return 1; + ERR_IF(!b->bm_pages) return 1; + + spin_lock_irqsave(&b->bm_lock, flags); + if (bm_is_locked(b)) + bm_print_lock_info(mdev); + for (bitnr = s; bitnr <= e; bitnr++) { + w = bitnr >> LN2_BPL; + if (page_nr != w >> (PAGE_SHIFT - LN2_BPL + 3)) { + page_nr = w >> (PAGE_SHIFT - LN2_BPL + 3); + if (p_addr) + bm_unmap(p_addr); + p_addr = bm_map_paddr(b, w); + } + ERR_IF (bitnr >= b->bm_bits) { + dev_err(DEV, "bitnr=%lu bm_bits=%lu\n", bitnr, b->bm_bits); + } else { + c += (0 != test_bit(bitnr - (page_nr << (PAGE_SHIFT+3)), p_addr)); + } + } + 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_conf *mdev, unsigned long enr) +{ + struct drbd_bitmap *b = mdev->bitmap; + int count, s, e; + unsigned long flags; + unsigned long *p_addr, *bm; + + ERR_IF(!b) return 0; + ERR_IF(!b->bm_pages) return 0; + + spin_lock_irqsave(&b->bm_lock, flags); + if (bm_is_locked(b)) + bm_print_lock_info(mdev); + + 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_paddr(b, s); + bm = p_addr + MLPP(s); + while (n--) + count += hweight_long(*bm++); + bm_unmap(p_addr); + } else { + dev_err(DEV, "start offset (%d) too large in drbd_bm_e_weight\n", s); + } + spin_unlock_irqrestore(&b->bm_lock, flags); + return count; +} + +/* set all bits covered by the AL-extent al_enr */ +unsigned long drbd_bm_ALe_set_all(struct drbd_conf *mdev, unsigned long al_enr) +{ + struct drbd_bitmap *b = mdev->bitmap; + unsigned long *p_addr, *bm; + unsigned long weight; + int count, s, e, i, do_now; + ERR_IF(!b) return 0; + ERR_IF(!b->bm_pages) return 0; + + spin_lock_irq(&b->bm_lock); + if (bm_is_locked(b)) + bm_print_lock_info(mdev); + weight = b->bm_set; + + s = al_enr * BM_WORDS_PER_AL_EXT; + e = min_t(size_t, s + BM_WORDS_PER_AL_EXT, b->bm_words); + /* assert that s and e are on the same page */ + D_ASSERT((e-1) >> (PAGE_SHIFT - LN2_BPL + 3) + == s >> (PAGE_SHIFT - LN2_BPL + 3)); + count = 0; + if (s < b->bm_words) { + i = do_now = e-s; + p_addr = bm_map_paddr(b, s); + bm = p_addr + MLPP(s); + while (i--) { + count += hweight_long(*bm); + *bm = -1UL; + bm++; + } + bm_unmap(p_addr); + b->bm_set += do_now*BITS_PER_LONG - count; + if (e == b->bm_words) + b->bm_set -= bm_clear_surplus(b); + } else { + dev_err(DEV, "start offset (%d) too large in drbd_bm_ALe_set_all\n", s); + } + weight = b->bm_set - weight; + spin_unlock_irq(&b->bm_lock); + return weight; +} |