From: Takashi Iwai <tiwai@suse.de>
To: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
autofs mailing list <autofs@vger.kernel.org>,
Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] autofs - use dentry flags to block walks during expire
Date: Thu, 01 Sep 2016 11:13:46 +0200 [thread overview]
Message-ID: <s5h4m60q8xh.wl-tiwai@suse.de> (raw)
In-Reply-To: <20160901012114.6476.57874.stgit@pluto.themaw.net>
On Thu, 01 Sep 2016 03:21:14 +0200,
Ian Kent wrote:
>
> Somewhere along the way the autofs expire operation has changed to
> hold a spin lock over expired dentry selection. The autofs indirect
> mount expired dentry selection is complicated and quite lengthy so
> it isn't appropriate to hold a spin lock over the operation.
>
> Commit 47be6184 added a might_sleep() to dput() causing a BUG()
> about this usage to be issued.
>
> But the spin lock doesn't need to be held over this check, the
> autofs dentry info. flags are enough to block walks into dentrys
> during the expire.
>
> I've left the direct mount expire as it is (for now) becuase it
> is much simpler and quicker than the indirect mount expire and
> adding spin lock release and re-aquires would do nothing more
> than add overhead.
>
> Signed-off-by: Ian Kent <raven@themaw.net>
Looks working fine, so far.
Reported-and-tested-by: Takashi Iwai <tiwai@suse.de>
thanks,
Takashi
next prev parent reply other threads:[~2016-09-01 9:13 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-01 1:21 [PATCH] autofs - use dentry flags to block walks during expire Ian Kent
2016-09-01 9:13 ` Takashi Iwai [this message]
2016-09-09 1:39 ` NeilBrown
2016-09-09 3:52 ` Ian Kent
2016-09-12 1:40 Ian Kent
2016-09-12 10:06 ` Takashi Iwai
2016-09-12 21:07 ` Andrew Morton
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