Hi Tom, Tom Haynes pÃÅ¡e v po 03. 12. 2007 v 01:35 -0600: > Milan Jurik wrote: > > Hi Alan, > > > > Alan M Wright pÃÂà ¡e v pá 30. 11. 2007 v 18:27 -0800: > > > >> I would recommend that, at a minimum, this proposal include > >> journaling. Some form of journaling or enhanced data > >> integrity guarantee is pretty much a requirement for file > >> systems now. > >> > >> If you include journaling during the initial implementation, > >> it will almost certainly be easier (technically) and lower > >> risk than adding it later. And it avoids a potential > >> on-disk format change later, which is always a good thing. > >> > >> > > > > ext3 as successor of ext2 didn't change on-disk format a lot, it is even > > possible to force mounting of ext3 as ext2. And future fork to ext3 is > > only depending on brain&manpower :-) > > > > > >> Is the plan to support the creation of ext file systems, > >> which would require utilities to do so, or just to mount > >> and work on existing ext file systems? > >> > >> > > > > As supervisor of the master thesis I requested only filesystem driver > > and mount utility. If somebody will need mkext2fs and fsck.ext2, he > > could recompile needed GNU utilities for it probably. > > > > Best regards, > > > > Milan > > > > > > Milan, > > ext2 is a non-starter for me. It would be worse than comparing a FAT16 to > a NTFS port. At least some people use FAT16. I don't know of anyone who > used ext2. > > So -1 as the project stands right now. > > I would prefer to see a project proposal which is to do ext3 and the > creation > of ext file systems. > > It doesn't have to be the case that your student needs to do ext3 and/or > these > file utilities. They can have the intermediate goal of getting ext2 up > and running. >
If you look to history, you will see that ext3 started as ext2 by adding journal support. The same source code, which was enhanced. Yes, the source code diverged during last years, but you can still access ext3 partition with ext2 filesystem driver. > And it may easily be the case that others will step up to do the remaining > work. Or you student may work on it after he graduates. In any event, > I much more prefer a forward looking project proposal than one with > a dead end. > Actually, it is not dead end, from your point of view, it is first part. And there are still many ext2 filesystems around and not everybody depends on journalling, ext2 is still used in embedded devices. I understand you want to enhance project proposal to ext3, but in that case somebody, not Jan, should investigate: a) if ext3 is documented enough (without studying ext3 Linux source code) b) if he has free time and will volunteer as the second project leader, working on ext3 fork > I'm also interested in how we verify that the implementation is > clean-room and > not tainted with a different license. Hmm, it is okay for the utilities > to be > GNU, since they are outside of the kernel. But we really need to make sure > that the file system code is clean. > Yes, I'm aware of it. My request was to ignore Linux source code. To verify that public documentation of ext2 is enough complete, Jan implemented user space utility to access ext2 based on that info. Before this project he hadn't ext2 Linux kernel code experience. We should publish all documentation he has, to avoid license issue. What else could be requested? I think this code will be codereview heavily, so if somebody will claim his copyright on some part of code, we could solve it. > I believe that having ext3 available is an interoperability that we > want. It will > make it that much easier to have dual or triple boot systems. It will allow > different OSes to share things like home directories on a laptop. > Sharing home directories between two OSes can be dangerous, because some applications can be surprised that their configs are for other versions of them. I agree ext3 in OpenSolaris should be added, but not as part of ext2 project proposal, I explained my reasons. > Please modify the proposal to start us along the path of eventually getting > ext3 in place. > -1 for this modification request, till time a) and b) will not be solved. Best regards, Milan
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