drbd: be less noisy with some log messages

We expect changes to a bitmap page in drbd_bm_write_page,
that's why we submit a copy page.

If a page changes during global writeout, that would be unexpected,
and reason to warn, though.

Also, often page writeout can be skipped (on activity log transactions
during normal operation, for example), no need to log that everytime.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_bitmap.c

@@ -920,8 +920,9 @@ static void bm_async_io_complete(struct bio *bio, int error)
 	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 ((ctx->flags & BM_AIO_COPY_PAGES) == 0 &&
+	    !bm_test_page_unchanged(b->bm_pages[idx]))
+		dev_warn(DEV, "bitmap page idx %u changed during IO!\n", idx);
 
 	if (error) {
 		/* ctx error will hold the completed-last non-zero error code,
@@ -1135,7 +1136,7 @@ int drbd_bm_write_page(struct drbd_conf *mdev, unsigned int idx) __must_hold(loc
 	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);
+		dynamic_dev_dbg(DEV, "skipped bm page write for idx %u\n", idx);
 		return 0;
 	}