#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.
+ *
- * 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...
+ * 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 pageing 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.
*/
/*
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...)
- */
+
+ /* see LIMITATIONS: above */
+
unsigned long bm_set; /* nr of set bits; THINK maybe atomic_t? */
unsigned long bm_bits;
size_t bm_words;
sector_t bm_dev_capacity;
struct mutex bm_change; /* serializes resize operations */
- atomic_t bm_async_io;
- wait_queue_head_t bm_io_wait;
+ wait_queue_head_t bm_io_wait; /* used to serialize IO of single pages */
unsigned long bm_flags;
/* definition of bits in bm_flags */
#define BM_LOCKED 0
-#define BM_MD_IO_ERROR 1
+// #define BM_MD_IO_ERROR 1 unused now.
#define BM_P_VMALLOCED 2
static int __bm_change_bits_to(struct drbd_conf *mdev, const unsigned long s,
mutex_unlock(&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)
+/* 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
+
+/* store_page_idx uses non-atomic assingment. 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));
+ page_private(page) |= idx;
+}
+
+static unsigned long bm_page_to_idx(struct page *page)
{
- struct page *page;
- unsigned long page_nr;
+ 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_conf *mdev, int page_nr)
+{
+ struct drbd_bitmap *b = mdev->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_conf *mdev, int page_nr)
+{
+ struct drbd_bitmap *b = mdev->bitmap;
+ void *addr = &page_private(b->bm_pages[page_nr]);
+ clear_bit(BM_PAGE_IO_LOCK, addr);
+ smp_mb__after_clear_bit();
+ wake_up(&mdev->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));
+}
+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; */
- page_nr = offset >> (PAGE_SHIFT - LN2_BPL + 3);
+ unsigned int page_nr = long_nr >> (PAGE_SHIFT - LN2_BPL + 3);
BUG_ON(page_nr >= b->bm_number_of_pages);
- page = b->bm_pages[page_nr];
+ 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, const enum km_type km)
+{
+ struct page *page = b->bm_pages[idx];
return (unsigned long *) kmap_atomic(page, km);
}
-static unsigned long * bm_map_paddr(struct drbd_bitmap *b, unsigned long offset)
+static unsigned long *bm_map_pidx(struct drbd_bitmap *b, unsigned int idx)
{
- return __bm_map_paddr(b, offset, KM_IRQ1);
+ return __bm_map_pidx(b, idx, KM_IRQ1);
}
static void __bm_unmap(unsigned long *p_addr, const enum km_type km)
* to be able to report device specific.
*/
+
static void bm_free_pages(struct page **pages, unsigned long number)
{
unsigned long i;
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 {
* 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)
{
- 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 mask;
unsigned long *p_addr, *bm;
+ int tmp;
+ int cleared = 0;
- p_addr = bm_map_paddr(b, w);
- bm = p_addr + MLPP(w);
- if (w < b->bm_words) {
+ /* 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;
- w++; bm++;
+ bm++;
}
- if (w < b->bm_words) {
+ 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;
}
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 mask;
unsigned long *p_addr, *bm;
-
- p_addr = bm_map_paddr(b, w);
- bm = p_addr + MLPP(w);
- if (w < b->bm_words) {
+ 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++; w++;
+ bm++;
}
- if (w < b->bm_words) {
- *bm = ~(0UL);
+ 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);
}
-static unsigned long __bm_count_bits(struct drbd_bitmap *b, const int swap_endian)
+/* 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, *bm, offset = 0;
+ unsigned long *p_addr;
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++);
- }
+ 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, KM_USER0);
+ for (i = 0; i < LWPP; i++)
+ bits += hweight_long(p_addr[i]);
__bm_unmap(p_addr, KM_USER0);
- offset += do_now;
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, KM_USER0);
+ 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, KM_USER0);
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;
+ unsigned int idx;
size_t do_now, end;
-#define BM_SECTORS_PER_BIT (BM_BLOCK_SIZE/512)
-
end = offset + len;
if (end > b->bm_words) {
while (offset < end) {
do_now = min_t(size_t, ALIGN(offset + 1, LWPP), end) - offset;
- p_addr = bm_map_paddr(b, 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) {
printk(KERN_ALERT "drbd: BUG BUG BUG! p_addr:%p bm:%p do_now:%d\n",
}
memset(bm, c, do_now * sizeof(long));
bm_unmap(p_addr);
+ bm_set_page_need_writeout(b->bm_pages[idx]);
offset += do_now;
}
}
int drbd_bm_resize(struct drbd_conf *mdev, sector_t capacity, int set_new_bits)
{
struct drbd_bitmap *b = mdev->bitmap;
- unsigned long bits, words, owords, obits, *p_addr, *bm;
+ unsigned long bits, words, owords, obits;
unsigned long want, have, onpages; /* number of pages */
struct page **npages, **opages = NULL;
int err = 0, growing;
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));
+ u64 bits_on_disk = ((u64)mdev->ldev->md.md_size_sect-MD_BM_OFFSET) << 12;
put_ldev(mdev);
+ if (bits > bits_on_disk) {
+ dev_info(DEV, "bits = %lu\n", bits);
+ dev_info(DEV, "bits_on_disk = %llu\n", bits_on_disk);
+ err = -ENOSPC;
+ goto out;
+ }
}
- /* one extra long to catch off by one errors */
- want = ALIGN((words+1)*sizeof(long), PAGE_SIZE) >> PAGE_SHIFT;
+ want = ALIGN(words*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))
+ if (drbd_insert_fault(mdev, DRBD_FAULT_BM_ALLOC))
npages = NULL;
else
npages = bm_realloc_pages(b, want);
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);
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);
+ dev_info(DEV, "resync bitmap: bits=%lu words=%lu pages=%lu\n", bits, words, want);
out:
drbd_bm_unlock(mdev);
struct drbd_bitmap *b = mdev->bitmap;
unsigned long *p_addr, *bm;
unsigned long word, bits;
+ unsigned int idx;
size_t end, do_now;
end = offset + number;
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);
+ 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 | lel_to_cpu(*buffer++);
+ 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,
*/
if (end == b->bm_words)
b->bm_set -= bm_clear_surplus(b);
-
spin_unlock_irq(&b->bm_lock);
}
else {
while (offset < end) {
do_now = min_t(size_t, ALIGN(offset+1, LWPP), end) - offset;
- p_addr = bm_map_paddr(b, 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++ = cpu_to_lel(*bm++);
+ *buffer++ = *bm++;
bm_unmap(p_addr);
}
}
spin_unlock_irq(&b->bm_lock);
}
+struct bm_aio_ctx {
+ struct drbd_conf *mdev;
+ atomic_t in_flight;
+ wait_queue_head_t io_wait;
+ unsigned flags;
+#define BM_AIO_COPY_PAGES 1
+ int error;
+};
+
+/* bv_page may be a copy, or may be the original */
static void bm_async_io_complete(struct bio *bio, int error)
{
- struct drbd_bitmap *b = bio->bi_private;
+ struct bm_aio_ctx *ctx = bio->bi_private;
+ struct drbd_conf *mdev = ctx->mdev;
+ struct drbd_bitmap *b = mdev->bitmap;
+ unsigned int idx = bm_page_to_idx(bio->bi_io_vec[0].bv_page);
int uptodate = bio_flagged(bio, BIO_UPTODATE);
if (!error && !uptodate)
error = -EIO;
+ if (!bm_test_page_unchanged(b->bm_pages[idx]))
+ dev_info(DEV, "bitmap page idx %u changed during IO!\n", idx);
+
if (error) {
- /* doh. what now?
- * for now, set all bits, and flag MD_IO_ERROR */
- __set_bit(BM_MD_IO_ERROR, &b->bm_flags);
+ /* ctx error will hold the completed-last non-zero error code,
+ * in case error codes differ. */
+ ctx->error = 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))
+ dev_err(DEV, "IO ERROR %d on bitmap page idx %u\n",
+ error, idx);
+ } else {
+ bm_clear_page_io_err(b->bm_pages[idx]);
+ dynamic_dev_dbg(DEV, "bitmap page idx %u completed\n", idx);
}
- if (atomic_dec_and_test(&b->bm_async_io))
- wake_up(&b->bm_io_wait);
+
+ bm_page_unlock_io(mdev, idx);
+
+ /* FIXME give back to page pool */
+ if (ctx->flags & BM_AIO_COPY_PAGES)
+ put_page(bio->bi_io_vec[0].bv_page);
bio_put(bio);
+
+ if (atomic_dec_and_test(&ctx->in_flight))
+ wake_up(&ctx->io_wait);
}
-static void bm_page_io_async(struct drbd_conf *mdev, struct drbd_bitmap *b, int page_nr, int rw) __must_hold(local)
+static void bm_page_io_async(struct bm_aio_ctx *ctx, 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);
+ struct drbd_conf *mdev = ctx->mdev;
+ struct drbd_bitmap *b = mdev->bitmap;
+ struct page *page;
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 */
+ * flexible external meta data device,
+ * or with PAGE_SIZE > 4k */
len = min_t(unsigned int, PAGE_SIZE,
(drbd_md_last_sector(mdev->ldev) - on_disk_sector + 1)<<9);
+ /* serialize IO on this page */
+ bm_page_lock_io(mdev, 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) {
+ /* FIXME alloc_page is good enough for now, but actually needs
+ * to use pre-allocated page pool */
+ void *src, *dest;
+ page = alloc_page(__GFP_HIGHMEM|__GFP_WAIT);
+ dest = kmap_atomic(page, KM_USER0);
+ src = kmap_atomic(b->bm_pages[page_nr], KM_USER1);
+ memcpy(dest, src, PAGE_SIZE);
+ kunmap_atomic(src, KM_USER1);
+ kunmap_atomic(dest, KM_USER0);
+ bm_store_page_idx(page, page_nr);
+ } else
+ page = b->bm_pages[page_nr];
+
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_add_page(bio, page, len, 0);
+ bio->bi_private = ctx;
bio->bi_end_io = bm_async_io_complete;
- if (FAULT_ACTIVE(mdev, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD)) {
+ if (drbd_insert_fault(mdev, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD)) {
bio->bi_rw |= rw;
bio_endio(bio, -EIO);
} else {
}
}
-# if defined(__LITTLE_ENDIAN)
- /* nothing to do, on disk == in memory */
-# define bm_cpu_to_lel(x) ((void)0)
-# else
-static 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)
+static int bm_rw(struct drbd_conf *mdev, int rw, unsigned lazy_writeout_upper_idx) __must_hold(local)
{
+ struct bm_aio_ctx ctx =
+ { .flags = lazy_writeout_upper_idx ? BM_AIO_COPY_PAGES : 0 };
struct drbd_bitmap *b = mdev->bitmap;
- /* sector_t sector; */
- int bm_words, num_pages, i;
+ int num_pages, i, count = 0;
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;
+ /*
+ * 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.
+ */
+ if (!ctx.flags)
+ WARN_ON(!bm_is_locked(b));
- /* on disk bitmap is little endian */
- if (rw == WRITE)
- bm_cpu_to_lel(b);
+ num_pages = b->bm_number_of_pages;
now = jiffies;
- atomic_set(&b->bm_async_io, num_pages);
- __clear_bit(BM_MD_IO_ERROR, &b->bm_flags);
+ ctx.mdev = mdev;
+ atomic_set(&ctx.in_flight, 1); /* one extra ref */
+ init_waitqueue_head(&ctx.io_wait);
+ ctx.error = 0;
/* 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);
+ for (i = 0; i < num_pages; i++) {
+ /* ignore completely unchanged pages */
+ if (lazy_writeout_upper_idx && i == lazy_writeout_upper_idx)
+ break;
+ if (rw & WRITE) {
+ if (bm_test_page_unchanged(b->bm_pages[i])) {
+ dynamic_dev_dbg(DEV, "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_dev_dbg(DEV, "skipped bm lazy write for idx %u\n", i);
+ continue;
+ }
+ }
+ atomic_inc(&ctx.in_flight);
+ bm_page_io_async(&ctx, i, rw);
+ ++count;
+ cond_resched();
+ }
- drbd_blk_run_queue(bdev_get_queue(mdev->ldev->md_bdev));
- wait_event(b->bm_io_wait, atomic_read(&b->bm_async_io) == 0);
+ atomic_dec(&ctx.in_flight); /* drop the extra ref */
+ wait_event(ctx.io_wait, atomic_read(&ctx.in_flight) == 0);
+ dev_info(DEV, "bitmap %s of %u pages took %lu jiffies\n",
+ rw == WRITE ? "WRITE" : "READ",
+ count, jiffies - now);
- if (test_bit(BM_MD_IO_ERROR, &b->bm_flags)) {
+ if (ctx.error) {
dev_alert(DEV, "we had at least one MD IO ERROR during bitmap IO\n");
- drbd_chk_io_error(mdev, 1, TRUE);
- err = -EIO;
+ drbd_chk_io_error(mdev, 1, true);
+ err = -EIO; /* ctx.error ? */
}
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);
+ b->bm_set = bm_count_bits(b);
dev_info(DEV, "recounting of set bits took additional %lu jiffies\n",
jiffies - now);
}
*/
int drbd_bm_read(struct drbd_conf *mdev) __must_hold(local)
{
- return bm_rw(mdev, READ);
+ return bm_rw(mdev, READ, 0);
}
/**
* drbd_bm_write() - Write the whole bitmap to its on disk location.
* @mdev: DRBD device.
+ *
+ * Will only write pages that have changed since last IO.
*/
int drbd_bm_write(struct drbd_conf *mdev) __must_hold(local)
{
- return bm_rw(mdev, WRITE);
+ return bm_rw(mdev, WRITE, 0);
+}
+
+/**
+ * drbd_bm_lazy_write_out() - Write bitmap pages 0 to @upper_idx-1, if they have changed.
+ * @mdev: 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_conf *mdev, unsigned upper_idx) __must_hold(local)
+{
+ return bm_rw(mdev, WRITE, upper_idx);
}
+
/**
- * drbd_bm_write_sect: Writes a 512 (MD_SECTOR_SIZE) byte piece of the bitmap
+ * drbd_bm_write_page: Writes a PAGE_SIZE aligned piece of bitmap
* @mdev: DRBD device.
- * @enr: Extent number in the resync lru (happens to be sector offset)
+ * @idx: bitmap page index
*
- * 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.
+ * We don't want to special case on logical_block_size of the backend device,
+ * so we submit PAGE_SIZE aligned pieces.
+ * Note that on "most" systems, PAGE_SIZE is 4k.
+ *
+ * In case this becomes an issue on systems with larger PAGE_SIZE,
+ * we may want to change this again to write 4k aligned 4k pieces.
*/
-int drbd_bm_write_sect(struct drbd_conf *mdev, unsigned long enr) __must_hold(local)
+int drbd_bm_write_page(struct drbd_conf *mdev, unsigned int idx) __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;
+ struct bm_aio_ctx ctx = { .flags = BM_AIO_COPY_PAGES, };
- 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);
+ if (bm_test_page_unchanged(mdev->bitmap->bm_pages[idx])) {
+ dev_info(DEV, "skipped bm page write for idx %u\n", idx);
+ return 0;
}
+
+ ctx.mdev = mdev;
+ atomic_set(&ctx.in_flight, 1);
+ init_waitqueue_head(&ctx.io_wait);
+
+ bm_page_io_async(&ctx, idx, WRITE_SYNC);
+ wait_event(ctx.io_wait, atomic_read(&ctx.in_flight) == 0);
+
+ if (ctx.error)
+ drbd_chk_io_error(mdev, 1, true);
+ /* that should force detach, so the in memory bitmap will be
+ * gone in a moment as well. */
+
mdev->bm_writ_cnt++;
- mutex_unlock(&mdev->md_io_mutex);
- return err;
+ return ctx.error;
}
/* NOTE
* find_first_bit returns int, we return unsigned long.
- * should not make much difference anyways, but ...
+ * 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!
*/
-#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. */
+ unsigned long bit_offset;
+ unsigned i;
+
if (bm_fo > b->bm_bits) {
dev_err(DEV, "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) {
- 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);
+ /* 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), km);
if (find_zero_bit)
- i = find_next_zero_bit(p_addr, PAGE_SIZE*8, bm_fo & BPP_MASK);
+ i = generic_find_next_zero_le_bit(p_addr,
+ PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK);
else
- i = find_next_bit(p_addr, PAGE_SIZE*8, bm_fo & BPP_MASK);
+ i = generic_find_next_le_bit(p_addr,
+ PAGE_SIZE*8, bm_fo & BITS_PER_PAGE_MASK);
__bm_unmap(p_addr, km);
if (i < PAGE_SIZE*8) {
- i = bit_offset + i;
- if (i >= b->bm_bits)
+ bm_fo = bit_offset + i;
+ if (bm_fo >= b->bm_bits)
break;
goto found;
}
bm_fo = bit_offset + PAGE_SIZE*8;
}
- i = -1UL;
+ bm_fo = DRBD_END_OF_BITMAP;
}
found:
- return i;
+ return bm_fo;
}
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;
+ unsigned long i = DRBD_END_OF_BITMAP;
ERR_IF(!b) return i;
ERR_IF(!b->bm_pages) return i;
struct drbd_bitmap *b = mdev->bitmap;
unsigned long *p_addr = NULL;
unsigned long bitnr;
- unsigned long last_page_nr = -1UL;
+ unsigned int last_page_nr = -1U;
int c = 0;
+ int changed_total = 0;
if (e >= b->bm_bits) {
dev_err(DEV, "ASSERT FAILED: bit_s=%lu bit_e=%lu bm_bits=%lu\n",
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);
+ unsigned int page_nr = bm_bit_to_page_idx(b, bitnr);
if (page_nr != last_page_nr) {
if (p_addr)
__bm_unmap(p_addr, km);
- p_addr = __bm_map_paddr(b, offset, km);
+ 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, km);
last_page_nr = page_nr;
}
if (val)
- c += (0 == __test_and_set_bit(bitnr & BPP_MASK, p_addr));
+ c += (0 == generic___test_and_set_le_bit(bitnr & BITS_PER_PAGE_MASK, p_addr));
else
- c -= (0 != __test_and_clear_bit(bitnr & BPP_MASK, p_addr));
+ c -= (0 != generic___test_and_clear_le_bit(bitnr & BITS_PER_PAGE_MASK, p_addr));
}
if (p_addr)
__bm_unmap(p_addr, km);
- b->bm_set += c;
- return c;
+ 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.
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;
+ p_addr = bm_map_pidx(b, bm_bit_to_page_idx(b, bitnr));
+ i = generic_test_le_bit(bitnr & BITS_PER_PAGE_MASK, p_addr) ? 1 : 0;
bm_unmap(p_addr);
} else if (bitnr == b->bm_bits) {
i = -1;
{
unsigned long flags;
struct drbd_bitmap *b = mdev->bitmap;
- unsigned long *p_addr = NULL, page_nr = -1;
+ unsigned long *p_addr = NULL;
unsigned long bitnr;
+ unsigned int page_nr = -1U;
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
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);
+ 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_paddr(b, w);
+ p_addr = bm_map_pidx(b, idx);
}
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));
+ c += (0 != generic_test_le_bit(bitnr - (page_nr << (PAGE_SHIFT+3)), p_addr));
}
}
if (p_addr)
count = 0;
if (s < b->bm_words) {
int n = e-s;
- p_addr = bm_map_paddr(b, 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++);
return count;
}
-/* set all bits covered by the AL-extent al_enr */
+/* Set all bits covered by the AL-extent al_enr.
+ * Returns number of bits changed. */
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;
+ unsigned long s, e;
+ int count, i, do_now;
ERR_IF(!b) return 0;
ERR_IF(!b->bm_pages) return 0;
count = 0;
if (s < b->bm_words) {
i = do_now = e-s;
- p_addr = bm_map_paddr(b, s);
+ p_addr = bm_map_pidx(b, bm_word_to_page_idx(b, s));
bm = p_addr + MLPP(s);
while (i--) {
count += hweight_long(*bm);
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);
+ dev_err(DEV, "start offset (%lu) too large in drbd_bm_ALe_set_all\n", s);
}
weight = b->bm_set - weight;
spin_unlock_irq(&b->bm_lock);
projects / karo-tx-linux.git / blobdiff