Re: NFS locking bug -- limited mtime resolution means nfs_lock() does not provide coherency guarantee

From: Andreas Dilger (adilger@turbolinux.com)
Date: Thu Sep 14 2000 - 18:10:28 EST


Ted writes:
>Trond Myklebust writes:
> Would it perhaps make sense to use one of these last 'free' fields
> as a pointer to an 'inode entension'?
> If you still want ext2fs to be able to accommodate new projects and
> ideas, then it seems that being able to extend the inode is a
> desirable feature, but perhaps this overlaps with the apparent plans
> for adding resource forks?
>
> For stuff that's not commonly used, perhaps. The problem is that you
> take a speed hit when you have to seek somewhere else to get at the
> inode extension. So for something which is going to have to be
> referenced for every stat() or getattr() operation, there are a real
> performance issues with doing something like that.

Note that there is already a patch for extended attributes for ext2.
These EAs are used for ACL support, but can be used for a variety of
other extensions to ext2. As Ted indicates, the EAs are stored in another
block, so it will reduce performance if the block is not already in
memory.

Cheers, Andreas

-- 
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert
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