linux-kernel - Re: [RFC PATCH 0/3] 9p: Further netfslib-related changes

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: <1400271.1706538135@warthog.procyon.org.uk>
Date: Mon, 29 Jan 2024 14:22:15 +0000
From: David Howells <dhowells@...hat.com>
To: Christian Schoenebeck <linux_oss@...debyte.com>
Cc: dhowells@...hat.com, Eric Van Hensbergen <ericvh@...nel.org>,
    Dominique Martinet <asmadeus@...ewreck.org>,
    Latchesar Ionkov <lucho@...kov.net>,
    Matthew Wilcox <willy@...radead.org>,
    Jeff Layton <jlayton@...nel.org>,
    Christian Brauner <christian@...uner.io>, netfs@...ts.linux.dev,
    v9fs@...ts.linux.dev, linux-fsdevel@...r.kernel.org,
    linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 0/3] 9p: Further netfslib-related changes

Christian Schoenebeck <linux_oss@...debyte.com> wrote:

> >  (1) Enable large folio support for 9p.  This is handled entirely by
> >      netfslib and is already supported in afs.  I wonder if we should limit
> >      the maximum folio size to 1MiB to match the maximum I/O size in the 9p
> >      protocol.
> 
> The limit depends on user's 'msize' 9p client option and on the 9p transport
> implementation. The hard limit with virtio transport for instance is currently
> just 500k (patches for virtio 4MB limit fetching dust unfortunately).

Okay.  Is that 500KiB or 512Kib?

> Would you see an advantage to limit folio size? I mean p9_client_read() etc.
> are automatically limiting the read/write chunk size accordingly.

For reads not so much, but for writes it would mean that a dirty folio is
either entirely written or entirely failed.  I don't know how important this
would be for the 9p usecases.

David