btrfs: make extent_clear_unlock_delalloc return void

Does not return any errors, nor anything from the callgraph.
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent_io.c

@@ -1820,7 +1820,7 @@ STATIC u64 find_lock_delalloc_range(struct inode *inode,
 	return found;
 }
 
-int extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
+void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
 				 struct page *locked_page,
 				 unsigned clear_bits,
 				 unsigned long page_ops)
@@ -1835,7 +1835,7 @@ int extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
 
 	clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
 	if (page_ops == 0)
-		return 0;
+		return;
 
 	if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
 		mapping_set_error(inode->i_mapping, -EIO);
@@ -1869,7 +1869,6 @@ int extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
 		index += ret;
 		cond_resched();
 	}
-	return 0;
 }
 
 /*

fs/btrfs/extent_io.h

@@ -340,7 +340,7 @@ int map_private_extent_buffer(struct extent_buffer *eb, unsigned long offset,
 		      unsigned long *map_len);
 int extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 end);
 int extent_range_redirty_for_io(struct inode *inode, u64 start, u64 end);
-int extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
+void extent_clear_unlock_delalloc(struct inode *inode, u64 start, u64 end,
 				 struct page *locked_page,
 				 unsigned bits_to_clear,
 				 unsigned long page_ops);