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From: Maxim Patlasov <mpatlasov@parallels.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: fuse-devel <fuse-devel@lists.sourceforge.net>,
	Anand Avati <avati@gluster.org>,
	Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/6] fuse: enable close_wait synchronous release
Date: Mon, 25 Aug 2014 19:27:31 +0400	[thread overview]
Message-ID: <53FB55E3.1050806@parallels.com> (raw)
In-Reply-To: <CAJfpegteyt_+g59skASpubFBSgs-c8XoOG-3Y+coKyr1nvyKfw@mail.gmail.com>

On 08/22/2014 06:04 PM, Miklos Szeredi wrote:
> On Thu, Aug 21, 2014 at 6:09 PM, Maxim Patlasov <MPatlasov@parallels.com> wrote:
>> The patch enables the feature by passing 'true' to fuse_file_put in
>> fuse_release_common.
>>
>> Previously, this was safe only in special cases when we sure that
>> multi-threaded userspace won't deadlock if we'll synchronously send
>> FUSE_RELEASE in the context of read-ahead or write-back callback. Now, it's
>> always safe because callbacks don't send requests to userspace anymore.
> But we do want to make this privileged, as there are unlikely but
> possible DoS scenarios with a sync release.

The latest patch of the set implements DISABLE_SYNC_RELEASE mount 
option. We can instrument fusermount to use the option by default for 
unprivileged mounts (allowing system administrator to configure it like 
"user_allow_other"). Do you have a better way to implement DoS 
protection in mind?

Thanks,
Maxim

  reply	other threads:[~2014-08-25 15:27 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-21 16:07 [PATCH 0/6] fuse: handle release synchronously (v3) Maxim Patlasov
2014-08-21 16:08 ` [PATCH 1/6] fuse: add FOPEN_SYNC_RELEASE flag to ff->open_flags Maxim Patlasov
2014-08-21 16:08 ` [PATCH 2/6] fuse: cosmetic rework of fuse_send_readpages Maxim Patlasov
2014-08-21 16:08 ` [PATCH 3/6] fuse: wait for end of IO on release Maxim Patlasov
2014-08-22 14:00   ` Miklos Szeredi
2014-08-25 15:12     ` Maxim Patlasov
2014-08-26  8:42   ` [PATCH 3/6] fuse: wait for end of IO on release (v2) Maxim Patlasov
2014-08-21 16:09 ` [PATCH 4/6] fuse: enable close_wait synchronous release Maxim Patlasov
2014-08-22 14:04   ` Miklos Szeredi
2014-08-25 15:27     ` Maxim Patlasov [this message]
2014-08-21 16:09 ` [PATCH 5/6] fuse: fix synchronous case of fuse_file_put() Maxim Patlasov
2014-08-22 14:08   ` Miklos Szeredi
2014-08-25 15:58     ` Maxim Patlasov
2014-09-11 16:14     ` Maxim Patlasov
2014-09-16  8:19       ` Miklos Szeredi
2014-09-24  7:19         ` Maxim Patlasov
2014-08-21 16:09 ` [PATCH 6/6] fuse: add mount option to disable synchronous release Maxim Patlasov
2014-08-22 14:09   ` Miklos Szeredi
2014-08-22 18:10     ` [fuse-devel] " Anand Avati

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