diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 2a3624adc0cf..17c508a941eb 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1988,9 +1988,12 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 	u64 nr_delalloc;
 	u64 delalloc_end;
 
+
 	WARN_ON(!PageLocked(page));
-	if (page->index > end_index) {
-		clear_extent_dirty(tree, start, page_end, GFP_NOFS);
+	page_offset = i_size & (PAGE_CACHE_SIZE - 1);
+	if (page->index > end_index ||
+	   (page->index == end_index && !page_offset)) {
+		page->mapping->a_ops->invalidatepage(page, 0);
 		unlock_page(page);
 		return 0;
 	}
@@ -1998,13 +2001,13 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
 	if (page->index == end_index) {
 		char *userpage;
 
-		size_t offset = i_size & (PAGE_CACHE_SIZE - 1);
-
 		userpage = kmap_atomic(page, KM_USER0);
-		memset(userpage + offset, 0, PAGE_CACHE_SIZE - offset);
-		flush_dcache_page(page);
+		memset(userpage + page_offset, 0,
+		       PAGE_CACHE_SIZE - page_offset);
 		kunmap_atomic(userpage, KM_USER0);
+		flush_dcache_page(page);
 	}
+	page_offset = 0;
 
 	set_page_extent_mapped(page);
 
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index df97d470812a..d968900c6973 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -305,7 +305,6 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
 	    (inline_size & (root->sectorsize -1)) == 0 ||
 	    inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root)) {
 		u64 last_end;
-		u64 existing_delalloc = 0;
 
 		for (i = 0; i < num_pages; i++) {
 			struct page *p = pages[i];
@@ -315,13 +314,6 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
 		last_end = (u64)(pages[num_pages -1]->index) <<
 				PAGE_CACHE_SHIFT;
 		last_end += PAGE_CACHE_SIZE - 1;
-		if (start_pos < isize) {
-			u64 delalloc_start = start_pos;
-			existing_delalloc = count_range_bits(io_tree,
-					     &delalloc_start,
-					     end_of_last_block, (u64)-1,
-					     EXTENT_DELALLOC);
-		}
 		set_extent_delalloc(io_tree, start_pos, end_of_last_block,
 				 GFP_NOFS);
 		btrfs_add_ordered_inode(inode);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 08760ff9bab7..40b4a8ec17fe 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1180,19 +1180,26 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
 		goto out;
 
 	ret = -ENOMEM;
+again:
 	page = grab_cache_page(mapping, index);
 	if (!page)
 		goto out;
 	if (!PageUptodate(page)) {
 		ret = btrfs_readpage(NULL, page);
 		lock_page(page);
+		if (page->mapping != mapping) {
+			unlock_page(page);
+			page_cache_release(page);
+			goto again;
+		}
 		if (!PageUptodate(page)) {
 			ret = -EIO;
 			goto out;
 		}
 	}
-	page_start = (u64)page->index << PAGE_CACHE_SHIFT;
 
+	page_start = (u64)page->index << PAGE_CACHE_SHIFT;
+	wait_on_page_writeback(page);
 	ret = btrfs_cow_one_page(inode, page, offset);
 
 	unlock_page(page);