From: David Howells <dhowells@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: dhowells@redhat.com, Trond Myklebust <trondmy@hammerspace.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Steve French <sfrench@samba.org>,
Dominique Martinet <asmadeus@codewreck.org>,
v9fs-developer@lists.sourceforge.net,
CIFS <linux-cifs@vger.kernel.org>,
Trond Myklebust <trond.myklebust@hammerspace.com>,
"open list:NFS, SUNRPC, AND..." <linux-nfs@vger.kernel.org>,
linux-cachefs@redhat.com, Dave Wysochanski <dwysocha@redhat.com>,
Shyam Prasad N <nspmangalore@gmail.com>,
Jeff Layton <jlayton@redhat.com>,
Matthew Wilcox <willy@infradead.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-afs@lists.infradead.org, ceph-devel@vger.kernel.org,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 00/10] fscache: Replace and remove old I/O API
Date: Fri, 29 Oct 2021 19:51:34 +0100 [thread overview]
Message-ID: <1891411.1635533494@warthog.procyon.org.uk> (raw)
In-Reply-To: <CAHk-=wg_C6V_S+Aox5Fn7MuFe13ADiRVnh6UcvY4WX9JjXn3dg@mail.gmail.com>
Linus Torvalds <torvalds@linux-foundation.org> wrote:
> But:
>
> > However, if you would rather I just removed all of fscache and (most of[*])
> > cachefiles, that I can do.
>
> I assume and think that if you just do that part first, then the
> "convert to netfslib" of afs and ceph at that later stage will mean
> that the fallback code will never be needed?
The netfslib coversions for afs and ceph are already in your tree and I have a
patch here to do that for 9p (if you're willing to take that in the upcoming
merge window?).
The issue is cifs[*] and nfs. I could leave caching in those disabled,
pending approved patches for those filesystems. This would mean that I
wouldn't need the fallback code.
An alternative is that I could move the "fallback" code into fs/nfs/fscache.c
and fs/cifs/fscache.c if that would be easier and merge it into the functions
there. The problem will come when the cache wants to do I/O in larger units
than page size to suit its own block size[**].
David
[*] As it happens, it turns out that cifs seems to have a bug in it that
causes the entire cache for a superblock to be discarded each time that
superblock is mounted.
[**] At some point the cache *has* to start keeping track of what data it is
holding rather than relying on bmap/SEEK_DATA/SEEK_HOLE to get round the
extent-bridging problem. I'm trying to take a leaf out of the book of other
caching filesystems and use larger block sizes (e.g. 256K) to reduce the
overhead of cache metadata.
prev parent reply other threads:[~2021-10-29 18:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-29 14:08 [PATCH v4 00/10] fscache: Replace and remove old I/O API David Howells
2021-10-29 14:09 ` [PATCH v4 01/10] fscache: Generalise the ->begin_read_operation method David Howells
2021-10-29 14:09 ` [PATCH v4 02/10] fscache: Fix fscache_cookie_enabled() to handle NULL cookie David Howells
2021-10-29 14:09 ` [PATCH v4 03/10] cachefiles: Always indicate we should fill a post-EOF page with zeros David Howells
2021-10-29 14:10 ` [PATCH v4 04/10] fscache: Implement a fallback I/O interface to replace the old API David Howells
2021-10-29 14:10 ` [PATCH v4 05/10] nfs: Move to using the alternate fallback fscache I/O API David Howells
2021-10-29 14:10 ` [PATCH v4 06/10] 9p: Convert to using the netfs helper lib to do reads and caching David Howells
2021-10-29 14:10 ` [PATCH v4 07/10] cifs: Move to using the alternate fallback fscache I/O API David Howells
2021-10-29 14:11 ` [PATCH v4 08/10] fscache: Remove the old " David Howells
2021-10-29 14:11 ` [PATCH v4 09/10] fscache: Remove stats that are no longer used David Howells
2021-10-29 14:11 ` [PATCH v4 10/10] fscache: Update the documentation to reflect I/O API changes David Howells
2021-10-29 16:49 ` [PATCH v4 00/10] fscache: Replace and remove old I/O API Linus Torvalds
2021-10-29 17:55 ` David Howells
2021-10-29 18:17 ` Linus Torvalds
2021-10-29 18:51 ` David Howells [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1891411.1635533494@warthog.procyon.org.uk \
--to=dhowells@redhat.com \
--cc=anna.schumaker@netapp.com \
--cc=asmadeus@codewreck.org \
--cc=ceph-devel@vger.kernel.org \
--cc=dwysocha@redhat.com \
--cc=jlayton@redhat.com \
--cc=linux-afs@lists.infradead.org \
--cc=linux-cachefs@redhat.com \
--cc=linux-cifs@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nfs@vger.kernel.org \
--cc=nspmangalore@gmail.com \
--cc=sfrench@samba.org \
--cc=torvalds@linux-foundation.org \
--cc=trond.myklebust@hammerspace.com \
--cc=trondmy@hammerspace.com \
--cc=v9fs-developer@lists.sourceforge.net \
--cc=viro@zeniv.linux.org.uk \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.