Hi all, Recently we encounter an issue in ext4. The issue is that, when we do a direct IO, ext4 will acquire inode->i_mutex in generic_file_aio_write(). It declines the performance. Here is the detailed conversation. http://www.spinics.net/lists/linux-ext4/msg30058.html I know that in xfs it uses i_iolock, which is a rw_semaphore, to make parallel operations in direct IO. But I have a question. As we do some read/write operations in direct IO, it seems that there has a window to cause data inconsistency. For example, One thread does a write operation to overlay some data at a offset. Meanwhile another thread does a read operation at the same offset. We assume that write is earlier than read. Hence, we should read new data. Although it is diffculty to occur, it is possible that read is issued to the disk firstly and we read old data. I don't know whether it exists or not in xfs. Thank you. Sorry, I don't subscribe this mailing list. Please CC to me <gnehzuil.liu@xxxxxxxxx>. Thank you. Regards, Zheng _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
