linux-kernel - Re: [PATCH v3 63/68] nfs: Convert to new fscache volume/cookie API

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: <1958026.1639747261@warthog.procyon.org.uk>
Date:   Fri, 17 Dec 2021 13:21:01 +0000
From:   David Howells <dhowells@...hat.com>
To:     David Wysochanski <dwysocha@...hat.com>
Cc:     dhowells@...hat.com, linux-cachefs <linux-cachefs@...hat.com>,
        Trond Myklebust <trond.myklebust@...merspace.com>,
        Anna Schumaker <anna.schumaker@...app.com>,
        linux-nfs <linux-nfs@...r.kernel.org>,
        Trond Myklebust <trondmy@...merspace.com>,
        Jeff Layton <jlayton@...nel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 63/68] nfs: Convert to new fscache volume/cookie API

David Wysochanski <dwysocha@...hat.com> wrote:

> >
> >  (4) fscache_enable/disable_cookie() have been removed.
> >
> >      Call fscache_use_cookie() and fscache_unuse_cookie() when a file is
> >      opened or closed to prevent a cache file from being culled and to keep
> >      resources to hand that are needed to do I/O.
> >
> >      Unuse the cookie when a file is opened for writing.  This is gated by
> >      the NFS_INO_FSCACHE flag on the nfs_inode.
> >
> >      A better way might be to invalidate it with FSCACHE_INVAL_DIO_WRITE
> >      which will keep it unused until all open files are closed.
> >
> 
> Comment still out of date here, reference
> https://marc.info/?l=linux-nfs&m=163922984027745&w=4

Okay, how about:

 (4) fscache_enable/disable_cookie() have been removed.

     Call fscache_use_cookie() and fscache_unuse_cookie() when a file is
     opened or closed to prevent a cache file from being culled and to keep
     resources to hand that are needed to do I/O.

     If a file is opened for writing, we invalidate it with
     FSCACHE_INVAL_DIO_WRITE in lieu of doing writeback to the cache,
     thereby making it cease caching until all currently open files are
     closed.  This should give the same behaviour as the uptream code.
     Making the cache store local modifications isn't straightforward for
     NFS, so that's left for future patches.

David