From: Dave Chinner <david@fromorbit.com>
To: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
linux-fsdevel@vger.kernel.org,
Nikola Ciprich <nikola.ciprich@linuxbox.cz>
Subject: Re: [PATCH] fs: Fix hang with BSD accounting on frozen filesystem
Date: Thu, 8 Nov 2012 16:22:56 +1100 [thread overview]
Message-ID: <20121108052256.GM6434@dastard> (raw)
In-Reply-To: <1352327499-17151-1-git-send-email-jack@suse.cz>
On Wed, Nov 07, 2012 at 11:31:39PM +0100, Jan Kara wrote:
> When BSD process accounting is enabled and logs information to a filesystem
> which gets frozen, system easily becomes unusable because each attempt to
> account process information blocks. Thus e.g. every task gets blocked in exit.
>
> It seems better to drop accounting information (which can already happen when
> filesystem is running out of space) instead of locking system up. This is
> implemented using a special flag FMODE_NO_FREEZE_WAIT in file->f_mode of a
> file to which accounting information is written.
I have no problems with making freeze waiting non-blocking, by why
invent a new flag for what is essentially an O_NONBLOCK operation?
Indeed, if someone opens a file O_NONBLOCK, shouldn't if behave
exactly the same on a frozen filesystem as this special
FMODE_NO_FREEZE_WAIT flag?
FWIW, nfsd could use this as well so that it doesn't block all the
nfsd threads trying to write to a frozen filesystem but instead
returns EJUKEBOX to the client to tell it ot wait for a while before
trying the operation again...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2012-11-08 5:23 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-07 22:31 [PATCH] fs: Fix hang with BSD accounting on frozen filesystem Jan Kara
2012-11-08 5:22 ` Dave Chinner [this message]
2012-11-08 8:09 ` Marco Stornelli
2012-11-08 10:18 ` Jan Kara
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