Messages in this thread | | | From | Andreas Dilger <> | Date | Mon, 3 Jun 2002 17:03:56 -0600 | Subject | Re: intent-based lookups (was Re: SMB filesystem) |
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On Jun 03, 2002 18:45 -0400, Ion Badulescu wrote: > On Sun, 2 Jun 2002 23:34:59 +0200 (CEST), Urban Widmark <urban@teststation.com> wrote: > > > Currently autofs has a problem where it won't show the mountpoints of > > non-mounted directories, but I think you would run into that problem too. > > (short version of the problem: how do you prevent 'ls -l' from mounting > > all filesystems in a directory?) > > You add the concept of a "light" lookup, and you make path_walk() call this > "light" lookup (be that a separate fs method, or a flag passed down to real > lookup()) iff the path component being looked up is the last component in > the path. A "light" lookup sets a flag in the inode signalling that the inode > is incomplete, so cached_lookup() can check this flag and call a "full" > lookup() (or perhaps a "full" revalidate()) if necessary. > > The actual details need to be thought out a bit more, this is only a general > outline. In particular, we need a bullet-proof way to determine when to > "upgrade" the inode from "light" to "full".
This may fit nicely with some work we are doing for Lustre (a scalable distributed filesystem for Linux) which needs to do "intent-based lookups". It has a similar desire to separate the lookups of the start of the path from the lookup of the last component of the path. Peter Braam (CC'd) has a patch for 2.4.18 which implements this. I pass the discussion over to him...
Cheers, Andreas -- Andreas Dilger http://www-mddsp.enel.ucalgary.ca/People/adilger/ http://sourceforge.net/projects/ext2resize/
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