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/bfs/file.c b/fs/bfs/file.c
index 88b9a3f..8fc2e9c 100644
--- a/fs/bfs/file.c
+++ b/fs/bfs/file.c
@@ -168,9 +168,17 @@
 			loff_t pos, unsigned len, unsigned flags,
 			struct page **pagep, void **fsdata)
 {
-	*pagep = NULL;
-	return block_write_begin(file, mapping, pos, len, flags,
-					pagep, fsdata, bfs_get_block);
+	int ret;
+
+	ret = block_write_begin(mapping, pos, len, flags, pagep,
+				bfs_get_block);
+	if (unlikely(ret)) {
+		loff_t isize = mapping->host->i_size;
+		if (pos + len > isize)
+			vmtruncate(mapping->host, isize);
+	}
+
+	return ret;
 }
 
 static sector_t bfs_bmap(struct address_space *mapping, sector_t block)