From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: Sick VFS question Date: Tue, 25 Feb 2003 09:57:30 -0800 Sender: linux-fsdevel-owner@vger.kernel.org Message-ID: <3E5BAE8A.7030607@zytor.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: Ion Badulescu , linux-fsdevel@vger.kernel.org, ezk@cs.sunysb.edu Return-path: To: "Charles P. Wright" List-Id: linux-fsdevel.vger.kernel.org Charles P. Wright wrote: > > I don't believe this is the case. > > I think what was suggested is EXT2 dentry (or other "real" fs) points to > an autofs inode. I'm not sure if this would work or not, but I don't > think it is the same as FiST-lite. > That is, indeed, what I'm trying to accomplish. > AFAIK, In FiST-lite what happens is the upper level (wrapfs) inode has its > address space operations set to the operations of the lower level (e.g., > EXT2) inode. A quick look at the code seemed to confirm this. > > The EXT2 dentry still points to the inode of ext2, and the wrapfs dentry > still points to a wrapfs inode. The change is wrapfs inode's > i_mapping->a_ops points to the EXT2 inode's i_mapping->a_ops. This sounds like it takes a file and "maps" it on top of another file -- something that would probably make a viable implementation of cachefs if we'd ever get around to implementing that... -hpa