Re: [bug report] NFS and uninterruptable wait states

[David Woodhouse <dwmw2@infradead.org>]

doug@wireboard.com said:
>  NFS does this (wait in D state) by default in order to prevent naive
> applications from getting timeout errors that they're not equipped to
> handle--the idea being that, if an NFS server goes down, programs
> using it will simply freeze and recover once it returns, rather than
> getting a timeout error and possibly becoming confused. 

Timeouts are a completely separate issue, surely? Applications ought to be 
able to deal with getting a _signal_ during a system call, whatever happens.

IMO, sleeping in state TASK_UNINTERRUPTIBLE in any situation where you can't
prove that the wakeup _will_ happen and will happen _soon_ should be
considered a bug - it's almost always just because someone hasn't bothered
to implement the cleanup code required for dealing with being interrupted.

/me tries to work out why anyone would ever want filesystem accesses to be 
uninterruptible.

--
dwmw2