drbd: bitmap keep track of changes vs on-disk bitmap
When we set or clear bits in a bitmap page,
also set a flag in the page->private pointer.
This allows us to skip writes of unchanged pages.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index e3f0f4d..090fc2c 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -262,6 +262,33 @@
spin_unlock_irqrestore(&mdev->al_lock, flags);
}
+#if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)
+/* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT
+ * are still coupled, or assume too much about their relation.
+ * Code below will not work if this is violated.
+ * Will be cleaned up with some followup patch.
+ */
+# error FIXME
+#endif
+
+static unsigned int al_extent_to_bm_page(unsigned int al_enr)
+{
+ return al_enr >>
+ /* bit to page */
+ ((PAGE_SHIFT + 3) -
+ /* al extent number to bit */
+ (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT));
+}
+
+static unsigned int rs_extent_to_bm_page(unsigned int rs_enr)
+{
+ return rs_enr >>
+ /* bit to page */
+ ((PAGE_SHIFT + 3) -
+ /* al extent number to bit */
+ (BM_EXT_SHIFT - BM_BLOCK_SHIFT));
+}
+
int
w_al_write_transaction(struct drbd_conf *mdev, struct drbd_work *w, int unused)
{
@@ -289,7 +316,7 @@
* For now, we must not write the transaction,
* if we cannot write out the bitmap of the evicted extent. */
if (mdev->state.conn < C_CONNECTED && evicted != LC_FREE)
- drbd_bm_write_sect(mdev, evicted/AL_EXT_PER_BM_SECT);
+ drbd_bm_write_page(mdev, al_extent_to_bm_page(evicted));
/* The bitmap write may have failed, causing a state change. */
if (mdev->state.disk < D_INCONSISTENT) {
@@ -636,105 +663,6 @@
}
/**
- * drbd_al_to_on_disk_bm() - * Writes bitmap parts covered by active AL extents
- * @mdev: DRBD device.
- *
- * Called when we detach (unconfigure) local storage,
- * or when we go from R_PRIMARY to R_SECONDARY role.
- */
-void drbd_al_to_on_disk_bm(struct drbd_conf *mdev)
-{
- int i, nr_elements;
- unsigned int enr;
- struct bio **bios;
- struct drbd_atodb_wait wc;
-
- ERR_IF (!get_ldev_if_state(mdev, D_ATTACHING))
- return; /* sorry, I don't have any act_log etc... */
-
- wait_event(mdev->al_wait, lc_try_lock(mdev->act_log));
-
- nr_elements = mdev->act_log->nr_elements;
-
- /* GFP_KERNEL, we are not in anyone's write-out path */
- bios = kzalloc(sizeof(struct bio *) * nr_elements, GFP_KERNEL);
- if (!bios)
- goto submit_one_by_one;
-
- atomic_set(&wc.count, 0);
- init_completion(&wc.io_done);
- wc.mdev = mdev;
- wc.error = 0;
-
- for (i = 0; i < nr_elements; i++) {
- enr = lc_element_by_index(mdev->act_log, i)->lc_number;
- if (enr == LC_FREE)
- continue;
- /* next statement also does atomic_inc wc.count and local_cnt */
- if (atodb_prepare_unless_covered(mdev, bios,
- enr/AL_EXT_PER_BM_SECT,
- &wc))
- goto free_bios_submit_one_by_one;
- }
-
- /* unnecessary optimization? */
- lc_unlock(mdev->act_log);
- wake_up(&mdev->al_wait);
-
- /* all prepared, submit them */
- for (i = 0; i < nr_elements; i++) {
- if (bios[i] == NULL)
- break;
- if (drbd_insert_fault(mdev, DRBD_FAULT_MD_WR)) {
- bios[i]->bi_rw = WRITE;
- bio_endio(bios[i], -EIO);
- } else {
- submit_bio(WRITE, bios[i]);
- }
- }
-
- /* always (try to) flush bitmap to stable storage */
- drbd_md_flush(mdev);
-
- /* In case we did not submit a single IO do not wait for
- * them to complete. ( Because we would wait forever here. )
- *
- * In case we had IOs and they are already complete, there
- * is not point in waiting anyways.
- * Therefore this if () ... */
- if (atomic_read(&wc.count))
- wait_for_completion(&wc.io_done);
-
- put_ldev(mdev);
-
- kfree(bios);
- return;
-
- free_bios_submit_one_by_one:
- /* free everything by calling the endio callback directly. */
- for (i = 0; i < nr_elements && bios[i]; i++)
- bio_endio(bios[i], 0);
-
- kfree(bios);
-
- submit_one_by_one:
- dev_warn(DEV, "Using the slow drbd_al_to_on_disk_bm()\n");
-
- for (i = 0; i < mdev->act_log->nr_elements; i++) {
- enr = lc_element_by_index(mdev->act_log, i)->lc_number;
- if (enr == LC_FREE)
- continue;
- /* Really slow: if we have al-extents 16..19 active,
- * sector 4 will be written four times! Synchronous! */
- drbd_bm_write_sect(mdev, enr/AL_EXT_PER_BM_SECT);
- }
-
- lc_unlock(mdev->act_log);
- wake_up(&mdev->al_wait);
- put_ldev(mdev);
-}
-
-/**
* drbd_al_apply_to_bm() - Sets the bitmap to diry(1) where covered ba active AL extents
* @mdev: DRBD device.
*/
@@ -813,7 +741,7 @@
return 1;
}
- drbd_bm_write_sect(mdev, udw->enr);
+ drbd_bm_write_page(mdev, rs_extent_to_bm_page(udw->enr));
put_ldev(mdev);
kfree(udw);
@@ -893,7 +821,6 @@
dev_warn(DEV, "Kicking resync_lru element enr=%u "
"out with rs_failed=%d\n",
ext->lce.lc_number, ext->rs_failed);
- set_bit(WRITE_BM_AFTER_RESYNC, &mdev->flags);
}
ext->rs_left = rs_left;
ext->rs_failed = success ? 0 : count;
@@ -912,7 +839,6 @@
drbd_queue_work_front(&mdev->data.work, &udw->w);
} else {
dev_warn(DEV, "Could not kmalloc an udw\n");
- set_bit(WRITE_BM_AFTER_RESYNC, &mdev->flags);
}
}
} else {
diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
index 8d959ed..72cd41a 100644
--- a/drivers/block/drbd/drbd_bitmap.c
+++ b/drivers/block/drbd/drbd_bitmap.c
@@ -70,8 +70,7 @@
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;
@@ -82,7 +81,7 @@
/* 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,
@@ -155,26 +154,117 @@
mutex_unlock(&b->bm_change);
}
-static unsigned int bm_bit_to_page_idx(struct drbd_bitmap *b, u64 bitnr)
+/* 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)
{
- /* 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;
+ BUG_ON(0 != (idx & ~BM_PAGE_IDX_MASK));
+ page_private(page) |= idx;
}
-/* word offset to long pointer */
-static unsigned long *__bm_map_paddr(struct drbd_bitmap *b, unsigned long offset, const enum km_type km)
+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;
+}
- return (unsigned long *) kmap_atomic(page, km);
+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)
@@ -188,11 +278,6 @@
return __bm_map_pidx(b, idx, KM_IRQ1);
}
-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);
@@ -222,6 +307,7 @@
* to be able to report device specific.
*/
+
static void bm_free_pages(struct page **pages, unsigned long number)
{
unsigned long i;
@@ -289,6 +375,9 @@
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 {
@@ -443,7 +532,7 @@
while (offset < words) {
i = do_now = min_t(size_t, words-offset, LWPP);
- p_addr = __bm_map_paddr(b, offset, KM_USER0);
+ p_addr = __bm_map_pidx(b, bm_word_to_page_idx(b, offset), KM_USER0);
bm = p_addr + MLPP(offset);
while (i--) {
bits += hweight_long(*bm++);
@@ -472,6 +561,7 @@
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)
@@ -485,7 +575,8 @@
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",
@@ -494,6 +585,7 @@
}
memset(bm, c, do_now * sizeof(long));
bm_unmap(p_addr);
+ bm_set_page_need_writeout(b->bm_pages[idx]);
offset += do_now;
}
}
@@ -604,7 +696,7 @@
bm_free_pages(opages + want, have - want);
}
- p_addr = bm_map_paddr(b, words);
+ p_addr = bm_map_pidx(b, bm_word_to_page_idx(b, words));
bm = p_addr + MLPP(words);
*bm = DRBD_MAGIC;
bm_unmap(p_addr);
@@ -616,7 +708,7 @@
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);
@@ -686,6 +778,7 @@
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;
@@ -700,7 +793,8 @@
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--) {
@@ -710,6 +804,7 @@
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,
@@ -748,7 +843,7 @@
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--)
@@ -786,9 +881,22 @@
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);
@@ -799,35 +907,79 @@
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 (drbd_insert_fault(mdev, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD)) {
@@ -841,36 +993,72 @@
/*
* 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 last_page, i, count = 0;
unsigned long now;
char ppb[10];
int err = 0;
- WARN_ON(!bm_is_locked(b));
+ /*
+ * 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));
- /* 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;
+ /* because of the "extra long to catch oob access" we allocate in
+ * drbd_bm_resize, bm_number_of_pages -1 is not necessarily the page
+ * containing the last _relevant_ bitmap word */
+ last_page = bm_word_to_page_idx(b, b->bm_words - 1);
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 <= last_page; 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();
+ }
- 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;
+ err = -EIO; /* ctx.error ? */
}
now = jiffies;
@@ -895,55 +1083,63 @@
*/
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_write_sect: Writes a 512 (MD_SECTOR_SIZE) byte piece of the bitmap
+ * drbd_bm_lazy_write_out() - Write bitmap pages 0 to @upper_idx-1, if they have changed.
* @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.
+ * @upper_idx: 0: write all changed pages; +ve: page index to stop scanning for changed pages
*/
-int drbd_bm_write_sect(struct drbd_conf *mdev, unsigned long enr) __must_hold(local)
+int drbd_bm_write_lazy(struct drbd_conf *mdev, unsigned upper_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;
+ return bm_rw(mdev, WRITE, upper_idx);
+}
- 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);
+
+/**
+ * drbd_bm_write_page: Writes a PAGE_SIZE aligned piece of bitmap
+ * @mdev: DRBD device.
+ * @idx: bitmap page index
+ *
+ * We don't want to special case on logical_block_size of the underlaying
+ * device, so we submit PAGE_SIZE aligned pieces containing the requested enr.
+ * Note that on "most" systems, PAGE_SIZE is 4k.
+ */
+int drbd_bm_write_page(struct drbd_conf *mdev, unsigned int idx) __must_hold(local)
+{
+ struct bm_aio_ctx ctx = { .flags = BM_AIO_COPY_PAGES, };
+
+ 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
@@ -965,10 +1161,9 @@
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);
+ /* bit offset of the first bit in the page */
+ bit_offset = bm_fo & ~BPP_MASK;
+ p_addr = __bm_map_pidx(b, bm_bit_to_page_idx(b, bm_fo), km);
if (find_zero_bit)
i = generic_find_next_zero_le_bit(p_addr, PAGE_SIZE*8, bm_fo & BPP_MASK);
@@ -1048,8 +1243,9 @@
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",
@@ -1057,12 +1253,17 @@
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)
@@ -1072,8 +1273,13 @@
}
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.
@@ -1211,8 +1417,7 @@
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);
+ p_addr = bm_map_pidx(b, bm_bit_to_page_idx(b, bitnr));
i = generic_test_le_bit(bitnr & BPP_MASK, p_addr) ? 1 : 0;
bm_unmap(p_addr);
} else if (bitnr == b->bm_bits) {
@@ -1231,10 +1436,10 @@
{
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
@@ -1247,12 +1452,12 @@
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);
@@ -1300,7 +1505,7 @@
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++);
@@ -1335,7 +1540,7 @@
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);
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index f6da48b..74cc50a 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -833,7 +833,7 @@
CRASHED_PRIMARY, /* This node was a crashed primary.
* Gets cleared when the state.conn
* goes into C_CONNECTED state. */
- WRITE_BM_AFTER_RESYNC, /* A kmalloc() during resync failed */
+ NO_BARRIER_SUPP, /* underlying block device doesn't implement barriers */
CONSIDER_RESYNC,
MD_NO_FUA, /* Users wants us to not use FUA/FLUSH on meta data dev */
@@ -1428,7 +1428,7 @@
const unsigned long s, const unsigned long e);
extern int drbd_bm_test_bit(struct drbd_conf *mdev, unsigned long bitnr);
extern int drbd_bm_e_weight(struct drbd_conf *mdev, unsigned long enr);
-extern int drbd_bm_write_sect(struct drbd_conf *mdev, unsigned long enr) __must_hold(local);
+extern int drbd_bm_write_page(struct drbd_conf *mdev, unsigned int idx) __must_hold(local);
extern int drbd_bm_read(struct drbd_conf *mdev) __must_hold(local);
extern int drbd_bm_write(struct drbd_conf *mdev) __must_hold(local);
extern unsigned long drbd_bm_ALe_set_all(struct drbd_conf *mdev,
@@ -1446,7 +1446,7 @@
/* for receive_bitmap */
extern void drbd_bm_merge_lel(struct drbd_conf *mdev, size_t offset,
size_t number, unsigned long *buffer);
-/* for _drbd_send_bitmap and drbd_bm_write_sect */
+/* for _drbd_send_bitmap */
extern void drbd_bm_get_lel(struct drbd_conf *mdev, size_t offset,
size_t number, unsigned long *buffer);
@@ -1641,7 +1641,6 @@
#define drbd_set_out_of_sync(mdev, sector, size) \
__drbd_set_out_of_sync(mdev, sector, size, __FILE__, __LINE__)
extern void drbd_al_apply_to_bm(struct drbd_conf *mdev);
-extern void drbd_al_to_on_disk_bm(struct drbd_conf *mdev);
extern void drbd_al_shrink(struct drbd_conf *mdev);
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 67fffad..57ed718 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1289,6 +1289,26 @@
}
}
+int drbd_bitmap_io_from_worker(struct drbd_conf *mdev, int (*io_fn)(struct drbd_conf *), char *why)
+{
+ int rv;
+
+ D_ASSERT(current == mdev->worker.task);
+
+ /* open coded non-blocking drbd_suspend_io(mdev); */
+ set_bit(SUSPEND_IO, &mdev->flags);
+ if (!is_susp(mdev->state))
+ D_ASSERT(atomic_read(&mdev->ap_bio_cnt) == 0);
+
+ drbd_bm_lock(mdev, why);
+ rv = io_fn(mdev);
+ drbd_bm_unlock(mdev);
+
+ drbd_resume_io(mdev);
+
+ return rv;
+}
+
/**
* after_state_ch() - Perform after state change actions that may sleep
* @mdev: DRBD device.
@@ -1404,7 +1424,12 @@
/* D_DISKLESS Peer becomes secondary */
if (os.peer == R_PRIMARY && ns.peer == R_SECONDARY)
- drbd_al_to_on_disk_bm(mdev);
+ drbd_bitmap_io_from_worker(mdev, &drbd_bm_write, "demote diskless peer");
+ put_ldev(mdev);
+ }
+
+ if (os.role == R_PRIMARY && ns.role == R_SECONDARY && get_ldev(mdev)) {
+ drbd_bitmap_io_from_worker(mdev, &drbd_bm_write, "demote");
put_ldev(mdev);
}
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 2f07249..77dc022 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -407,10 +407,8 @@
}
}
- if ((new_role == R_SECONDARY) && get_ldev(mdev)) {
- drbd_al_to_on_disk_bm(mdev);
- put_ldev(mdev);
- }
+ /* writeout of activity log covered areas of the bitmap
+ * to stable storage done in after state change already */
if (mdev->state.conn >= C_WF_REPORT_PARAMS) {
/* if this was forced, we should consider sync */
@@ -1174,7 +1172,10 @@
if (cp_discovered) {
drbd_al_apply_to_bm(mdev);
- drbd_al_to_on_disk_bm(mdev);
+ if (drbd_bitmap_io(mdev, &drbd_bm_write, "crashed primary apply AL")) {
+ retcode = ERR_IO_MD_DISK;
+ goto force_diskless_dec;
+ }
}
if (_drbd_bm_total_weight(mdev) == drbd_bm_bits(mdev))
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 9fe3e89..d17f2ed 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -907,10 +907,8 @@
drbd_md_sync(mdev);
- if (test_and_clear_bit(WRITE_BM_AFTER_RESYNC, &mdev->flags)) {
- dev_info(DEV, "Writing the whole bitmap\n");
- drbd_queue_bitmap_io(mdev, &drbd_bm_write, NULL, "write from resync_finished");
- }
+ dev_info(DEV, "Writing changed bitmap pages\n");
+ drbd_queue_bitmap_io(mdev, &drbd_bm_write, NULL, "write from resync_finished");
if (khelper_cmd)
drbd_khelper(mdev, khelper_cmd);
@@ -1127,7 +1125,6 @@
mdev->ov_last_oos_size = size>>9;
}
drbd_set_out_of_sync(mdev, sector, size);
- set_bit(WRITE_BM_AFTER_RESYNC, &mdev->flags);
}
int w_e_end_ov_reply(struct drbd_conf *mdev, struct drbd_work *w, int cancel)