Date: Sun, 1 Dec 2002 07:43:12 -0500 (EST) From: "Adam Migus" <adam@migus.org> To: <current@FreeBSD.org> Subject: nullfs/unionfs Message-ID: <49407.192.168.4.1.1038746592.squirrel@mail.migus.org>
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Recently I've been doing some twisted things with nullfs/unionfs. I've managed to contain myself to using read-only nullfs, but, the whole point of the unionfs usage is to isolate changes (ie. I need read-write). Anyway I've hit a VFS bug that upon reading current@, appears as though it might be related to the bug involving vnode backed md's. I just discovered the bug and know no more about it than what has been discussed in the related post. The only thing I can add is that when it happens to me, a shutdown of the system results in a panic due to an invalid ref count on the problematic vnode. The count goes negative. When the system comes back up, an fsck shows every inode in sequence from the bad one as unreferenced. I read the man pages for nullfs/unionfs. They mentioned that the code is orphaned and buggy. So, I blamed it, and entertained the idea of claiming ownership, now, or in future. Right now I sit somewhere in the middle of the (IMHO) rather steep VFS learning curve. Therefor even if I did sit down and attempt to track it I'd likely have limited success and if I found the bug, it'd probably be nowhere near nullfs/unionfs... In summary, two things. First WRT the nullfs/unionfs. I'd like to use it as I've tried to thus far. So I have an intrinsic motivation to get it fixed. Seems as though others do as well (assuming it's the same bug). So I think I'll have a go at it, but won't promise results as I'm not a VFS guru. Second, if anyone expresses interest in ownership of the nullfs/unionfs code, I'd like to work with them. If no one does and someone wants me to, I may, but at a later date when I'm more comfortable doing so. Third, if someone else attempts to find/fix the bug, consider me an interested. -- Adam Migus (adam@migus.org) (amigus@TrustedBSD.org) TrustedBSD (http://www.trustedbsd.org) | The Power To Secure To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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