ocfs2: Initialize count in aio_write before generic_write_checks

generic_write_checks() expects count to be initialized to the size of
the write.  Writes to files open with O_DIRECT|O_LARGEFILE write 0 bytes
because count is uninitialized.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.de>
Signed-off-by: Joel Becker <joel.becker@oracle.com>

fs/ocfs2/file.c

@@ -1851,6 +1851,7 @@ relock:
 		if (ret)
 			goto out_dio;
 
+		count = ocount;
 		ret = generic_write_checks(file, ppos, &count,
 					   S_ISBLK(inode->i_mode));
 		if (ret)