lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <a979a5bc-f2bc-7035-beed-6a3919471d39@virtuozzo.com>
Date:   Fri, 24 Dec 2021 15:07:38 +0300
From:   Vasily Averin <vvs@...tuozzo.com>
To:     Dominique Martinet <asmadeus@...ewreck.org>
Cc:     Eric Van Hensbergen <ericvh@...il.com>,
        Latchesar Ionkov <lucho@...kov.net>, kernel@...nvz.org,
        v9fs-developer@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
        "J. Bruce Fields" <bfields@...ldses.org>
Subject: Re: [PATCH] v9fs: handle async processing of F_SETLK with FL_SLEEP
 flag

On 24.12.2021 10:31, Dominique Martinet wrote:
> If that process is made asynchronous, we need a way to run more
> 9p-specific code in that one's lm_grant callback, so we can proceed onto
> the second step which is...
> 
>  - send the lock request to the 9p server and wait for its reply
> (note that the current code is always synchronous here: even if you
> request SETLK without the SLEEP flag you can be made to wait here.
> I have work in the closest to make some requests asynchronous, so
> locking could be made asynchronous when that lands, but my code
> introduced a race somewhere I haven't had the time to fix so this
> improvement will come later)
> 
> What would you suggest with that?

It isn't necessary to make  request asynchronous,
it's enough to avoid blocking locks.
As far as  I understand blocking does not happen for SETLK command,
so it should be enough to chenge first part and call non-blocking 
posix_file_lock() instead of blocking locks_lock_file_wait().

It would be great to make processing of 2nd part asynchronous too,
but I think it looks like over-engineering, because we even are not
100% sure that someone really uses this functionality.

Thank you,
	Vasily Averin

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ