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From: Marko Rauhamaa <marko.rauhamaa@f-secure.com>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Jeff Layton <jlayton@poochiereds.net>,
	Al Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Jan Kara <jack@suse.cz>,
	Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
	<linux-api@vger.kernel.org>
Subject: Re: fanotify read returns with errno == EOPENSTALE
Date: Fri, 21 Apr 2017 16:13:39 +0300	[thread overview]
Message-ID: <871ssl9a4c.fsf@drapion.f-secure.com> (raw)
In-Reply-To: <CAOQ4uxiJyrvEJMhM1jhiE5pCgP0iA_LL4Eo_h7UY00wkTKhbTg@mail.gmail.com> (Amir Goldstein's message of "Thu, 20 Apr 2017 16:34:55 +0300")

Amir Goldstein <amir73il@gmail.com>:

> On Thu, Apr 20, 2017 at 3:43 PM, Marko Rauhamaa
> <marko.rauhamaa@f-secure.com> wrote:
>> Amir Goldstein <amir73il@gmail.com>:
>>
>>> Sorry I messed up the previous patch. please try this one:
>>
>> I will try it.

Tried it. Superficially, it seems to be working, but...

>> More importantly, does EAGAIN here still guarantee EPOLLET semantics
>> of epoll(7)? IOW, if I get EAGAIN, I shouldn't have to try read(2)ing
>> the fanotify fd again before calling epoll_wait(2).
>
> Yes, if you get EAGAIN it means there are no more events in the queue,
> so shouldn't have to try read again.

I ran into a system hang with our real product that suggests there might
be a problem left. It would be explained if your patch generated an
EAGAIN while there were other events waiting in the queue.

I will have to investigate further.


Marko

-- 
+358 44 990 4795
Skype: marko.rauhamaa_f-secure

  reply	other threads:[~2017-04-21 13:13 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-22 15:31 fanotify read returns with errno == EOPENSTALE Marko Rauhamaa
2017-03-22 18:01 ` Matthew Wilcox
2017-03-22 18:20 ` Amir Goldstein
2017-03-22 19:17   ` Amir Goldstein
2017-03-22 19:31   ` Al Viro
2017-03-22 19:39     ` Amir Goldstein
2017-03-23  8:13       ` Marko Rauhamaa
2017-03-23 11:46         ` Amir Goldstein
2017-03-23 11:56           ` Jeff Layton
2017-03-23 12:43             ` Marko Rauhamaa
2017-03-23 13:47               ` Amir Goldstein
2017-04-19 13:46                 ` Marko Rauhamaa
2017-04-20 11:06                   ` Amir Goldstein
2017-04-20 11:33                     ` Amir Goldstein
2017-04-20 12:43                       ` Marko Rauhamaa
2017-04-20 13:34                         ` Amir Goldstein
2017-04-21 13:13                           ` Marko Rauhamaa [this message]
2017-04-20 14:20                       ` Jan Kara
2017-04-20 15:06                         ` Amir Goldstein
2017-04-22  7:22                           ` Amir Goldstein
2017-04-24  7:40                             ` Marko Rauhamaa

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