linux-kernel - Re: Ctrl+C doesn't interrupt process waiting for I/O

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Message-ID: <48671A12.90205@goop.org>
Date:	Sat, 28 Jun 2008 22:13:54 -0700
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Avi Kivity <avi@...ranet.com>
CC:	Török Edwin <edwintorok@...il.com>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: Ctrl+C doesn't interrupt process waiting for I/O

Avi Kivity wrote:
>>
>> Yes, it's intended behaviour.  Filesystem IO syscalls are considered 
>> "fast" and are interruptible.  Usermode code can reasonably expect 
>> that file IO will never return EINTR.
>
> That's filesystem dependent; if you mount an nfs filesystem with the 
> 'intr' mount option, it will be interruptible (which makes sense, as 
> it is impossible to guarantee the server's responsiveness).

'intr' is a pretty bad idea, and I would never recommend it ('soft' is 
better).  It's an excellent way to destroy data when a stray signal 
causes a syscall to fail with EINTR in an unexpected way (write being 
the obvious one, but link, unlink, truncate or even close can fail in 
odd ways can cause havok).

I don't know of any other filesystem with a similarly bad option.

    J
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