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Diffstat (limited to 'drivers/block/drbd/drbd_bitmap.c')
-rw-r--r--drivers/block/drbd/drbd_bitmap.c1697
1 files changed, 1697 insertions, 0 deletions
diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
new file mode 100644
index 0000000000..85ca000a05
--- /dev/null
+++ b/drivers/block/drbd/drbd_bitmap.c
@@ -0,0 +1,1697 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ 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>.
+
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/bitmap.h>
+#include <linux/vmalloc.h>
+#include <linux/string.h>
+#include <linux/drbd.h>
+#include <linux/slab.h>
+#include <linux/highmem.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;
+
+ /* exclusively to be used by __al_write_transaction(),
+ * drbd_bm_mark_for_writeout() and
+ * and drbd_bm_write_hinted() -> bm_rw() called from there.
+ */
+ unsigned int n_bitmap_hints;
+ unsigned int al_bitmap_hints[AL_UPDATES_PER_TRANSACTION];
+
+ /* 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 (!drbd_ratelimit())
+ 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));
+}
+
+void drbd_bm_reset_al_hints(struct drbd_device *device)
+{
+ device->bitmap->n_bitmap_hints = 0;
+}
+
+/**
+ * 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 drbd_bitmap *b = device->bitmap;
+ 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];
+ BUG_ON(b->n_bitmap_hints >= ARRAY_SIZE(b->al_bitmap_hints));
+ if (!test_and_set_bit(BM_PAGE_HINT_WRITEOUT, &page_private(page)))
+ b->al_bitmap_hints[b->n_bitmap_hints++] = page_nr;
+}
+
+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 inline void bm_vk_free(void *ptr)
+{
+ kvfree(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;
+ 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_ZERO);
+ if (!new_pages)
+ return NULL;
+ }
+
+ 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);
+ 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);
+ */
+ }
+
+ return new_pages;
+}
+
+/*
+ * 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, 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, device->bitmap))
+ return;
+ bm_free_pages(device->bitmap->bm_pages, device->bitmap->bm_number_of_pages);
+ bm_vk_free(device->bitmap->bm_pages);
+ 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.
+ */
+#ifndef BITS_PER_PAGE
+#define BITS_PER_PAGE (1UL << (PAGE_SHIFT + 3))
+#define BITS_PER_PAGE_MASK (BITS_PER_PAGE - 1)
+#else
+# if BITS_PER_PAGE != (1UL << (PAGE_SHIFT + 3))
+# error "ambiguous BITS_PER_PAGE"
+# endif
+#endif
+#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, last_word;
+
+ /* all but last page */
+ for (idx = 0; idx < b->bm_number_of_pages - 1; idx++) {
+ p_addr = __bm_map_pidx(b, idx);
+ bits += bitmap_weight(p_addr, BITS_PER_PAGE);
+ __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);
+ bits += bitmap_weight(p_addr, last_word * BITS_PER_LONG);
+ 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;
+ bool growing;
+
+ if (!expect(device, 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;
+
+ 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);
+ 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 = PFN_UP(words*sizeof(long));
+ 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);
+ 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(device, b))
+ return 0;
+ if (!expect(device, 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(device, b))
+ return 0;
+ if (!expect(device, 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(device, 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(device, b))
+ return;
+ if (!expect(device, 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(device, b))
+ return;
+ if (!expect(device, 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(device, b))
+ return;
+ if (!expect(device, 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(device, b))
+ return;
+ if (!expect(device, 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_first_page_all(bio));
+
+ 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_status) {
+ /* ctx error will hold the completed-last non-zero error code,
+ * in case error codes differ. */
+ ctx->error = blk_status_to_errno(bio->bi_status);
+ bm_set_page_io_err(b->bm_pages[idx]);
+ /* Not identical to on disk version of it.
+ * Is BM_PAGE_IO_ERROR enough? */
+ if (drbd_ratelimit())
+ drbd_err(device, "IO ERROR %d on bitmap page idx %u\n",
+ bio->bi_status, 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);
+ }
+}
+
+/* For the layout, see comment above drbd_md_set_sector_offsets(). */
+static inline sector_t drbd_md_last_bitmap_sector(struct drbd_backing_dev *bdev)
+{
+ switch (bdev->md.meta_dev_idx) {
+ case DRBD_MD_INDEX_INTERNAL:
+ case DRBD_MD_INDEX_FLEX_INT:
+ return bdev->md.md_offset + bdev->md.al_offset -1;
+ case DRBD_MD_INDEX_FLEX_EXT:
+ default:
+ return bdev->md.md_offset + bdev->md.md_size_sect -1;
+ }
+}
+
+static void bm_page_io_async(struct drbd_bm_aio_ctx *ctx, int page_nr) __must_hold(local)
+{
+ struct drbd_device *device = ctx->device;
+ enum req_op op = ctx->flags & BM_AIO_READ ? REQ_OP_READ : REQ_OP_WRITE;
+ struct drbd_bitmap *b = device->bitmap;
+ struct bio *bio;
+ struct page *page;
+ sector_t last_bm_sect;
+ sector_t first_bm_sect;
+ sector_t on_disk_sector;
+ unsigned int len;
+
+ first_bm_sect = device->ldev->md.md_offset + device->ldev->md.bm_offset;
+ on_disk_sector = first_bm_sect + (((sector_t)page_nr) << (PAGE_SHIFT-SECTOR_SHIFT));
+
+ /* this might happen with very small
+ * flexible external meta data device,
+ * or with PAGE_SIZE > 4k */
+ last_bm_sect = drbd_md_last_bitmap_sector(device->ldev);
+ if (first_bm_sect <= on_disk_sector && last_bm_sect >= on_disk_sector) {
+ sector_t len_sect = last_bm_sect - on_disk_sector + 1;
+ if (len_sect < PAGE_SIZE/SECTOR_SIZE)
+ len = (unsigned int)len_sect*SECTOR_SIZE;
+ else
+ len = PAGE_SIZE;
+ } else {
+ if (drbd_ratelimit()) {
+ drbd_err(device, "Invalid offset during on-disk bitmap access: "
+ "page idx %u, sector %llu\n", page_nr, on_disk_sector);
+ }
+ ctx->error = -EIO;
+ bm_set_page_io_err(b->bm_pages[page_nr]);
+ 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);
+ }
+ return;
+ }
+
+ /* 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_NOIO | __GFP_HIGHMEM);
+ copy_highpage(page, b->bm_pages[page_nr]);
+ bm_store_page_idx(page, page_nr);
+ } else
+ page = b->bm_pages[page_nr];
+ bio = bio_alloc_bioset(device->ldev->md_bdev, 1, op, GFP_NOIO,
+ &drbd_md_io_bio_set);
+ bio->bi_iter.bi_sector = on_disk_sector;
+ __bio_add_page(bio, page, len, 0);
+ bio->bi_private = ctx;
+ bio->bi_end_io = drbd_bm_endio;
+
+ if (drbd_insert_fault(device, (op == REQ_OP_WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD)) {
+ bio_io_error(bio);
+ } else {
+ submit_bio(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;
+ unsigned 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 = KREF_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... */
+
+ if (flags & BM_AIO_READ) {
+ for (i = 0; i < num_pages; i++) {
+ atomic_inc(&ctx->in_flight);
+ bm_page_io_async(ctx, i);
+ ++count;
+ cond_resched();
+ }
+ } else if (flags & BM_AIO_WRITE_HINTED) {
+ /* ASSERT: BM_AIO_WRITE_ALL_PAGES is not set. */
+ unsigned int hint;
+ for (hint = 0; hint < b->n_bitmap_hints; hint++) {
+ i = b->al_bitmap_hints[hint];
+ if (i >= num_pages) /* == -1U: no hint here. */
+ continue;
+ /* Several AL-extents may point to the same page. */
+ if (!test_and_clear_bit(BM_PAGE_HINT_WRITEOUT,
+ &page_private(b->bm_pages[i])))
+ continue;
+ /* Has it even changed? */
+ if (bm_test_page_unchanged(b->bm_pages[i]))
+ continue;
+ atomic_inc(&ctx->in_flight);
+ bm_page_io_async(ctx, i);
+ ++count;
+ }
+ } else {
+ 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_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) {
+ unsigned int ms = jiffies_to_msecs(jiffies - now);
+ if (ms > 5) {
+ drbd_info(device, "bitmap %s of %u pages took %u ms\n",
+ (flags & BM_AIO_READ) ? "READ" : "WRITE",
+ count, ms);
+ }
+ }
+
+ 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,
+ struct drbd_peer_device *peer_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,
+ struct drbd_peer_device *peer_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,
+ struct drbd_peer_device *peer_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,
+ struct drbd_peer_device *peer_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(device, b))
+ return i;
+ if (!expect(device, 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(device, b))
+ return 1;
+ if (!expect(device, 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]);
+
+ /* I think it is more cache line friendly to hweight_long then set to ~0UL,
+ * than to first bitmap_weight() all words, then bitmap_fill() all words */
+ 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(device, b))
+ return 0;
+ if (!expect(device, 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(device, b))
+ return 1;
+ if (!expect(device, 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(device, 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(device, b))
+ return 0;
+ if (!expect(device, 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);
+ count += bitmap_weight(bm, n * BITS_PER_LONG);
+ 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;
+}