linux-kernel - Re: [PATCH] fs: Make write(2) interruptible by a fatal signal

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Message-ID: <CAO9iq9GwoJD0AJnpS8dLXUT_KfTvaWTd4k8MUpACTR4q=zqR3g@mail.gmail.com>
Date:	Fri, 2 Dec 2011 13:58:30 +0200
From:	Janne Blomqvist <blomqvist.janne@...il.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Matthew Wilcox <matthew@....cx>,
	Wu Fengguang <fengguang.wu@...el.com>, Jan Kara <jack@...e.cz>,
	LKML <linux-kernel@...r.kernel.org>,
	"linux-fsdevel@...r.kernel.org" <linux-fsdevel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Theodore Ts'o" <tytso@....edu>
Subject: Re: [PATCH] fs: Make write(2) interruptible by a fatal signal

On Thu, Dec 1, 2011 at 18:10, Linus Torvalds
<torvalds@...ux-foundation.org> wrote:
> On Thu, Dec 1, 2011 at 6:27 AM, Matthew Wilcox <matthew@....cx> wrote:
>>
>> Another problem scenario is an NFS mounted file going away while the
>> user is writing to it.  The user should be able to kill the stuck process
>> without rebooting their machine.
>
> Well, NFS has always had the 'intr' mount option.

For some values of always; My nfs(5) manpage says:

"The intr / nointr mount option is deprecated after kernel 2.6.25.
Only SIGKILL can interrupt a pending NFS operation on these  kernels,
and
if specified, this mount option is ignored to provide backwards
compatibility with older kernels."

(Apparently this was related to the introduction of TASK_KILLABLE.)

Isn't this pretty much the same "common sense" semantics that Jan's
patch is introducing?

Wu's testing in this thread suggests that at some point this
TASK_KILLABLE for nfs writer thing was broken, or didn't work very
robustly to begin with? Anyway, awesome if it's getting fixed, not
only for NFS but for all regular files!

-- 
Janne Blomqvist
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