From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Mason Subject: Some nilfs comments Date: Wed, 17 Dec 2008 21:52:55 -0500 Message-ID: <1229568775.27170.134.camel@think.oraclecorp.com> Reply-To: NILFS Users mailing list Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: users-bounces-JrjvKiOkagjYtjvyW6yDsg@public.gmane.org Errors-To: users-bounces-JrjvKiOkagjYtjvyW6yDsg@public.gmane.org To: users-JrjvKiOkagjYtjvyW6yDsg@public.gmane.org Hello, I've been meaning to read through nilfs for a while, and I grabbed the code today to take a look. The code is very clean and it ran well out of the box here. One problem I hit early on was that nilfs doesn't seem to zero out the block device during mkfs. So after mkfs.nilfs2, mount still found my old btrfs filesystem. It would be a good idea to zero out the first and last 1MB on the device (except for the first sector which might have the partition table). I haven't dug too deeply in yet, but if there are parts you're most interested in comments on, please let me know. It looks like nilfs_writepage ignores WB_SYNC_NONE, which is used by do_sync_mapping_range(). nilfs_page_mkwrite doesn't seem to dirty the page? block_page_mkwrite does more, including checks against i_size and others. readpages and O_DIRECT both set b_size on the map_bh to reflect the total size of the region they are trying to map. It seems like an easy optimization to map more in nilfs_get_block. Hopefully this helps, I'll try to send a few more ideas after I get to know the code better. -chris