linux-kernel - Re: [GIT PULL] fscache rewrite -- please drop for now

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: <672169.1597074488@warthog.procyon.org.uk>
Date:   Mon, 10 Aug 2020 16:48:08 +0100
From:   David Howells <dhowells@...hat.com>
To:     Steve French <smfrench@...il.com>
Cc:     dhowells@...hat.com,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Matthew Wilcox <willy@...radead.org>,
        Christoph Hellwig <hch@....de>,
        Jeff Layton <jlayton@...hat.com>,
        Dave Wysochanski <dwysocha@...hat.com>,
        Trond Myklebust <trondmy@...merspace.com>,
        Anna Schumaker <anna.schumaker@...app.com>,
        Steve French <sfrench@...ba.org>,
        Eric Van Hensbergen <ericvh@...il.com>,
        linux-cachefs@...hat.com, linux-afs@...ts.infradead.org,
        linux-nfs <linux-nfs@...r.kernel.org>,
        CIFS <linux-cifs@...r.kernel.org>, ceph-devel@...r.kernel.org,
        v9fs-developer@...ts.sourceforge.net,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [GIT PULL] fscache rewrite -- please drop for now

Steve French <smfrench@...il.com> wrote:

> cifs.ko also can set rsize quite small (even 1K for example, although
> that will be more than 10x slower than the default 4MB so hopefully no
> one is crazy enough to do that).

You can set rsize < PAGE_SIZE?

> I can't imagine an SMB3 server negotiating an rsize or wsize smaller than
> 64K in today's world (and typical is 1MB to 8MB) but the user can specify a
> much smaller rsize on mount.  If 64K is an adequate minimum, we could change
> the cifs mount option parsing to require a certain minimum rsize if fscache
> is selected.

I've borrowed the 256K granule size used by various AFS implementations for
the moment.  A 512-byte xattr can thus hold a bitmap covering 1G of file
space.

David