From: Marko Rauhamaa <marko.rauhamaa-xdZvthzU1HpWk0Htik3J/w@public.gmane.org>
To: Amir Goldstein <amir73il-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Jeff Layton <jlayton-vpEMnDpepFuMZCB2o+C8xQ@public.gmane.org>,
Al Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
linux-fsdevel
<linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Jan Kara <jack-AlSwsSmVLrQ@public.gmane.org>,
Linux NFS Mailing List
<linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.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-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> (Amir Goldstein's message of "Thu, 20 Apr 2017 16:34:55 +0300")
Amir Goldstein <amir73il-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>:
> On Thu, Apr 20, 2017 at 3:43 PM, Marko Rauhamaa
> <marko.rauhamaa-xdZvthzU1HpWk0Htik3J/w@public.gmane.org> wrote:
>> Amir Goldstein <amir73il-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>:
>>
>>> 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
WARNING: multiple messages have this Message-ID (diff)
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
next prev parent reply other threads:[~2017-04-21 13:13 UTC|newest]
Thread overview: 32+ 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
[not found] ` <8760j02mfz.fsf-q6puBR44SRrF1m+2HNTUelaTQe2KTcn/@public.gmane.org>
2017-03-23 13:47 ` Amir Goldstein
2017-03-23 13:47 ` Amir Goldstein
2017-03-23 13:47 ` Amir Goldstein
[not found] ` <CAOQ4uxja14p02jQurLTGv_fHrs+UBa5qfacrgY_-7tyv6UJqdw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-04-19 13:46 ` Marko Rauhamaa
2017-04-19 13:46 ` Marko Rauhamaa
[not found] ` <87lgqwa4tg.fsf-q6puBR44SRrF1m+2HNTUelaTQe2KTcn/@public.gmane.org>
2017-04-20 11:06 ` Amir Goldstein
2017-04-20 11:06 ` Amir Goldstein
[not found] ` <CAOQ4uxirSfVVYBexXrWccDHnE5oqxNgUh3-X5Ey1w4R=nHXDjA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-04-20 11:33 ` Amir Goldstein
2017-04-20 11:33 ` Amir Goldstein
[not found] ` <CAOQ4uxjA8Z7wnwuHFCKeKT1xz0Gh-qS40Y6cfPi3fAM0MKsRuQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-04-20 12:43 ` Marko Rauhamaa
2017-04-20 12:43 ` Marko Rauhamaa
[not found] ` <87shl38d1x.fsf-q6puBR44SRrF1m+2HNTUelaTQe2KTcn/@public.gmane.org>
2017-04-20 13:34 ` Amir Goldstein
2017-04-20 13:34 ` Amir Goldstein
[not found] ` <CAOQ4uxiJyrvEJMhM1jhiE5pCgP0iA_LL4Eo_h7UY00wkTKhbTg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-04-21 13:13 ` Marko Rauhamaa [this message]
2017-04-21 13:13 ` Marko Rauhamaa
2017-04-20 14:20 ` Jan Kara
[not found] ` <20170420142035.GE22135-4I4JzKEfoa/jFM9bn6wA6Q@public.gmane.org>
2017-04-20 15:06 ` Amir Goldstein
2017-04-20 15:06 ` Amir Goldstein
[not found] ` <CAOQ4uxgAOJjWP6PHY6WgOkNK0vmaTWnFZN+Jvea7zpjJ_VU8Bw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-04-22 7:22 ` Amir Goldstein
2017-04-22 7:22 ` Amir Goldstein
[not found] ` <CAOQ4uxgkXz+8=m2o_faAh2g2Z21KhAf67WckgPNWhktz1=DaWA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-04-24 7:40 ` Marko Rauhamaa
2017-04-24 7:40 ` Marko Rauhamaa
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