linux-kernel - Re: [patch 16/52] fs: dcache RCU for multi-step operaitons

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: <1277366290.1875.891.camel@laptop>
Date:	Thu, 24 Jun 2010 09:58:10 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	npiggin@...e.de
Cc:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	John Stultz <johnstul@...ibm.com>,
	Frank Mayhar <fmayhar@...gle.com>
Subject: Re: [patch 16/52] fs: dcache RCU for multi-step operaitons

On Thu, 2010-06-24 at 13:02 +1000, npiggin@...e.de wrote:
> plain text document attachment (fs-dcache_lock-multi-step.patch)
> The remaining usages for dcache_lock is to allow atomic, multi-step read-side
> operations over the directory tree by excluding modifications to the tree.
> Also, to walk in the leaf->root direction in the tree where we don't have
> a natural d_lock ordering.
> 
> This could be accomplished by taking every d_lock, but this would mean a
> huge number of locks and actually gets very tricky.
> 
> Solve this instead by using the rename seqlock for multi-step read-side
> operations. Insert operations are not serialised. Delete operations are
> tricky when walking up the directory our parent might have been deleted
> when dropping locks so also need to check and retry for that.
> 
> XXX: hmm, we could of course just take the rename lock if there is any worry
> about livelock. Most of these are slow paths.


Ah, does this address John's issue? 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/