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  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]
Date:   Mon, 3 Feb 2020 18:46:41 +0100
From:   Christoph Hellwig <>
To:     Dave Chinner <>
Cc:     Christoph Hellwig <>,,, Waiman Long <>,
        Peter Zijlstra <>,
        Thomas Gleixner <>,
        Ingo Molnar <>, Will Deacon <>,
        Andrew Morton <>,,,,
Subject: Re: RFC: hold i_rwsem until aio completes

On Sat, Jan 18, 2020 at 08:28:38PM +1100, Dave Chinner wrote:
> I think it's pretty gross, actually. It  makes the same mistake made
> with locking in the old direct IO code - it encodes specific lock
> operations via flags into random locations in the DIO path. This is
> a very slippery slope, and IMO it is an layering violation to encode
> specific filesystem locking smeantics into a layer that is supposed
> to be generic and completely filesystem agnostic. i.e.  this
> mechanism breaks if a filesystem moves to a different type of lock
> (e.g. range locks), and history teaches us that we'll end up making
> a horrible, unmaintainable mess to support different locking
> mechanisms and contexts.
> I think that we should be moving to a model where the filesystem
> provides an unlock method in the iomap operations structure, and if
> the method is present in iomap_dio_complete() it gets called for the
> filesystem to unlock the inode at the appropriate point. This also
> allows the filesystem to provide a different method for read or
> write unlock, depending on what type of lock it held at submission.
> This gets rid of the need for the iomap code to know what type of
> lock the caller holds, too.

I'd rather avoid yet another method.  But I think with a little
tweaking we can move the unlock into the ->end_io method.

Powered by blists - more mailing lists