Revert:
commit 914ee295af418e936ec20a08c1663eaabe4cd07a
Author: Xin Zhong <xin.zhong@intel.com>
Date: Thu Dec 9 09:30:14 2010 +0000
Btrfs: pwrite blocked when writing from the mmaped buffer of the same page
This problem is found in meego testing:
http://bugs.meego.com/show_bug.cgi?id=6672
A file in btrfs is mmaped and the mmaped buffer is passed to pwrite to write
of the same file. In btrfs_file_aio_write(), the pages is locked by prepare_
...
