get rid of block_write_begin_newtrunc

Move the call to vmtruncate to get rid of accessive blocks to the callers
in preparation of the new truncate sequence and rename the non-truncating
version to block_write_begin.

While we're at it also remove several unused arguments to block_write_begin.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 1dd9e6a..5c694ec 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -197,11 +197,15 @@
 	if (unlikely(err))
 		return err;
 
-	*pagep = NULL;
-	err = block_write_begin(file, mapping, pos, len, flags, pagep,
-				fsdata, nilfs_get_block);
-	if (unlikely(err))
+	err = block_write_begin(mapping, pos, len, flags, pagep,
+				nilfs_get_block);
+	if (unlikely(err)) {
+		loff_t isize = mapping->host->i_size;
+		if (pos + len > isize)
+			vmtruncate(mapping->host, isize);
+
 		nilfs_transaction_abort(inode->i_sb);
+	}
 	return err;
 }