Re: [autofs] [RFC] Towards a Modern Autofs

[H. Peter Anvin]

Jim Carter wrote:
> 
>>For justification to it's worth, some institutions have file servers
>>that export hundreds or even thousands of shares over NFS.   As /net is
>>really just a kind of executable indirect map that returns multimounts
>>for each hostname used as a key,  just doing 'cd /net/hostname' may
>>potentially mount hundreds of filesystems.  This is not cool!
> 
> Definitely not cool.  But some users (yours truly among them) do "alias ls
> 'ls -F'", which requires "ls" to stat (and thus mount) every exported
> filesystem.  More uncool, and I don't see any non-disgusting way around it.
> 

No, it doesn't... this has been covered several times already.  It
requires ls to *lstat* the point; it only does a stat() if the resulting
entry is S_IFLNK.  The same is true for GUI tools.  There is a fairly
easy way to distinguish lstat() from virtually all other filesystem
calls -- it doesn't invoke follow_link.  So the answer is simply to
create an inode which is S_IFDIR but has a follow_link method.  The
follow_link method triggers a mount.  This is called a "pseudo-symlink
directory" or sometimes "ghost directory".

	-hpa

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