On Sun, 2007-12-02 at 21:37 +0100, Michael Kerrisk wrote: > On Dec 2, 2007 3:32 PM, Timo Sirainen <[EMAIL PROTECTED]> wrote: > > Package: manpages-dev > > Version: 2.64-1 > > Severity: normal > > > > "O_EXCL is broken on NFS file systems" is wrong. Rather it should be "O_EXCL > > doesn't work on NFSv2 file systems". And since pretty much everyone uses at > > least NFSv3 nowadays I don't think it's worth mentioning the link() > > workaround anymore. > > Timo, > > Can you provide pointers to further information about O_EXCL working > for NFSv3 and later? I am no NFS expert.
It seems to be pretty difficult to find useful information about how different NFS clients and servers work. I started writing http://iki.fi/tss/nfs-coding-howto.html a while ago and tested several OSes' NFS clients. They all supported O_EXCL. http://nfs.sourceforge.net/ says that O_EXCL has worked in Linux since v2.6.5. NFSv3 RFC (http://www.faqs.org/rfcs/rfc1813.html) talks about EXCLUSIVE and GUARDED creation modes which both work for O_EXCL, so at least in theory all NFSv3 clients and servers should support it. Looks like Linux kernel has code that if server doesn't support either EXCLUSIVE or GUARDED it fallbacks to using unguarded create instead of giving an error. I don't know if there are any servers not supporting it though.
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