Re: [GIT PULL] Please pull NFS client bugfixes....

[Linus Torvalds]

On Thu, 7 Jan 2010, Linus Torvalds wrote:
> 
> However, I still suspect that the lock inversion problem can probably be 
> fixed without any of that at all. Maybe you can just break the chain 
> somewhere else. I've not actually seen the lockdep chain, so I don't know 
> the deails. Pointers?

For example, if we're talking about readdir having a lock the other way 
(NFS lock taken before the mmap_sem), it's entirely possible that there is 
nothing to "fix" but some lockdep annotation.

You cannot mmap a directory (and you can't readdir a non-directory), so if 
it's a per-inode NFS lock, then the simplest fix _might_ be to just put 
directory locks in a different lockdep class from non-directory locks. 
That might fix it.

Of course, if it's not a per-inode lock, that doesn't help.

And maybe I'm missing something entirely, and such games with lockdep 
classes are pointless, and I'm a moron. Quite possible.

		Linus
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