Messages in this thread | | | Date | Wed, 31 Dec 2003 16:48:24 -0700 | From | Andreas Dilger <> | Subject | Re: udev and devfs - The final word |
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On Dec 31, 2003 22:55 +0000, viro@parcelfarce.linux.theplanet.co.uk wrote: > h) nfsd uses device number as a substitute for export ID if said > ID is not given explicitly. That, BTW, is a big problem for crackpipe > dreams about random device numbers - export ID _must_ be stable across > reboots.
We had a problem with this and Lustre, when we NFS export it. Lustre is already a network filesystem so we don't have a device number. I had a discussion with Neil Brown about this and suggested that we allow NFS to get a _real_ stable export ID from the filesystem (e.g. superblock UUID or similar) instead of the device number hackery which only has a vague relationship to stable.
We implemented it for Lustre with a filesystem option FS_NFSEXP_FSID that tells nfsd it can export such a filesystem in the absence of FS_REQUIRES_DEV and then put our export ID into sb->s_dev (although I'd prefer something slightly cleaner than that).
Cheers, Andreas -- Andreas Dilger http://sourceforge.net/projects/ext2resize/ http://www-mddsp.enel.ucalgary.ca/People/adilger/
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