diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 289f1f09481d..18c90cbb5fad 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -42,6 +42,7 @@
 #include "discard.h"
 #include "space-info.h"
 #include "zoned.h"
+#include "subpage.h"
 
 #define BTRFS_SUPER_FLAG_SUPP	(BTRFS_HEADER_FLAG_WRITTEN |\
 				 BTRFS_HEADER_FLAG_RELOC |\
@@ -992,14 +993,48 @@ static void btree_invalidatepage(struct page *page, unsigned int offset,
 static int btree_set_page_dirty(struct page *page)
 {
 #ifdef DEBUG
+	struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
+	struct btrfs_subpage *subpage;
 	struct extent_buffer *eb;
+	int cur_bit = 0;
+	u64 page_start = page_offset(page);
 
-	BUG_ON(!PagePrivate(page));
-	eb = (struct extent_buffer *)page->private;
-	BUG_ON(!eb);
-	BUG_ON(!test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
-	BUG_ON(!atomic_read(&eb->refs));
-	btrfs_assert_tree_locked(eb);
+	if (fs_info->sectorsize == PAGE_SIZE) {
+		BUG_ON(!PagePrivate(page));
+		eb = (struct extent_buffer *)page->private;
+		BUG_ON(!eb);
+		BUG_ON(!test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
+		BUG_ON(!atomic_read(&eb->refs));
+		btrfs_assert_tree_locked(eb);
+		return __set_page_dirty_nobuffers(page);
+	}
+	ASSERT(PagePrivate(page) && page->private);
+	subpage = (struct btrfs_subpage *)page->private;
+
+	ASSERT(subpage->dirty_bitmap);
+	while (cur_bit < BTRFS_SUBPAGE_BITMAP_SIZE) {
+		unsigned long flags;
+		u64 cur;
+		u16 tmp = (1 << cur_bit);
+
+		spin_lock_irqsave(&subpage->lock, flags);
+		if (!(tmp & subpage->dirty_bitmap)) {
+			spin_unlock_irqrestore(&subpage->lock, flags);
+			cur_bit++;
+			continue;
+		}
+		spin_unlock_irqrestore(&subpage->lock, flags);
+		cur = page_start + cur_bit * fs_info->sectorsize;
+
+		eb = find_extent_buffer(fs_info, cur);
+		ASSERT(eb);
+		ASSERT(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
+		ASSERT(atomic_read(&eb->refs));
+		btrfs_assert_tree_locked(eb);
+		free_extent_buffer(eb);
+
+		cur_bit += (fs_info->nodesize >> fs_info->sectorsize_bits);
+	}
 #endif
 	return __set_page_dirty_nobuffers(page);
 }