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Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20200810164044.GA31753@lst.de> References: <20200810164044.GA31753@lst.de> <1851200.1596472222@warthog.procyon.org.uk> <447452.1596109876@warthog.procyon.org.uk> <667820.1597072619@warthog.procyon.org.uk> To: Christoph Hellwig Cc: dhowells@redhat.com, Alexander Viro , Matthew Wilcox , Jeff Layton , Dave Wysochanski , Trond Myklebust , Anna Schumaker , Steve French , Eric Van Hensbergen , linux-cachefs@redhat.com, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [GIT PULL] fscache rewrite -- please drop for now MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <1428310.1598542135.1@warthog.procyon.org.uk> Date: Thu, 27 Aug 2020 16:28:55 +0100 Message-ID: <1428311.1598542135@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org Christoph Hellwig wrote: > FYI, a giant rewrite dropping support for existing consumer is always > rather awkward. Is there any way you could pre-stage some infrastructure > changes, and then do a temporary fscache2, which could then be renamed > back to fscache once everyone switched over? That's a bit tricky. There are three points that would have to be shared: the userspace miscdev interface, the backing filesystem and the single index tree. It's probably easier to just have a go at converting 9P and cifs. Making the old and new APIs share would be a fairly hefty undertaking in its own right. David