Alex Hornung <[email protected]> writes: > On 28/03/11 16:48, Naohiro Aota wrote: >> about implementing a new unionfs: >> >>> The current unionfs is completely broken as it relies on the whiteout >>> VFS technique which is not supported by HAMMER. >> >> - Then main work would be to implement whiteout feature on HAMMER? >> - or rewrite unionfs code not to depend on whiteout technique? > > I've now changed the text on the projects page to reflect that we don't > want a new unionfs using whiteout. So the aim of this project is to > develop a unionfs from scratch avoiding techniques which require messing > with other filesystems.
I see. I'd like to know what features to be implemented on the "new unionfs". Are there any working or developing example on other BSDs or on Linux? I mean the "new unionfs" would have features like FreeBSD unionfs or Linux aufs2 [1], or much different thing? >> and also: >> >> - Are there some docs (or some source code file) to help me understand >> DragonFly VFS and HAMMER internal? >> - Are there some detailed guides about these ideas? > > About the VFS you can refer to the book "Design & Implementation of > FreeBSD". Things have changed, but it gives a good general perspective > of how things work. The namecache, most interesting part for unionfs, > has no real documentation, only inline with the code. Thanks! I'll check the book and the code. [1] http://aufs.sourceforge.net/ Regards, Naohiro
