Xref: utzoo news.software.b:8515 news.software.readers:129 Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!spool.mu.edu!uunet!mcsun!ukc!warwick!cudcv From: cudcv@warwick.ac.uk (Rob McMahon) Newsgroups: news.software.b,news.software.readers Subject: Re: Two queries regarding C-News (one of which also hits rn) Message-ID: <=05{_AC@warwick.ac.uk> Date: 29 Jun 91 12:56:40 GMT Article-I.D.: warwick.=05{_AC References: Sender: news@warwick.ac.uk (Network news) Organization: Computing Services, Warwick University, UK Lines: 41 Nntp-Posting-Host: shark In article francis@cis.ohio-state.edu (RD Francis) writes: >rn users have, on two or three separate occasions now, been told that all of >their newsgroups were bogus, and been unsubscribed from everything. I >suspect that this has occurred at the same time as I've been running addgroup >(and maybe delgroup). One reason I know for this is NFS. If you remove a file from the server while a client has it open, all operations on the file will fail with ESTALE. So programs that update the file in place are fine, as are programs which do rm -f active.old ln active active.old && mv active.new active the *first* time. If you repeat this, however, the file which an `rn' running on a client has open no longer exists, and it panics and thinks all the groups have been removed. `Addgroup' uses the first method, `delgroup' uses the second method, and cause this problem (well in fact it does `mv active active.old ; mv active.tmp active': wouldn't the above be better ? (no time when active doesn't exist)). `Expire' and `upact', but I think not `updatemin', also do this which can cause trouble if you leave rn running overnight. The real solution must be to change rn to notice that read operations are failing, and to close and reread the active file. Another solution would be to use something like ln active "active.keep/`date`.$$" instead, and mopup after all "reasonable" rn's should have exited (a day or two ?). Cheers, Rob -- UUCP: ...!mcsun!ukc!warwick!cudcv PHONE: +44 203 523037 JANET: cudcv@uk.ac.warwick INET: cudcv@warwick.ac.uk Rob McMahon, Computing Services, Warwick University, Coventry CV4 7AL, England