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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 9 Feb 2021 11:06:41 -0800
Message-ID: <CAHk-=wj-k86FOqAVQ4ScnBkX3YEKuMzqTEB2vixdHgovJpHc9w@mail.gmail.com>
Subject: Re: [GIT PULL] fscache: I/O API modernisation and netfs helper library
To:     David Howells <dhowells@redhat.com>
Cc:     Matthew Wilcox <willy@infradead.org>,
        Jeff Layton <jlayton@redhat.com>,
        David Wysochanski <dwysocha@redhat.com>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        Trond Myklebust <trondmy@hammerspace.com>,
        Steve French <sfrench@samba.org>,
        Dominique Martinet <asmadeus@codewreck.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        ceph-devel@vger.kernel.org, linux-afs@lists.infradead.org,
        linux-cachefs@redhat.com, CIFS <linux-cifs@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        "open list:NFS, SUNRPC, AND..." <linux-nfs@vger.kernel.org>,
        v9fs-developer@lists.sourceforge.net,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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So I'm looking at this early, because I have more time now than I will
have during the merge window, and honestly, your pull requests have
been problematic in the past.

The PG_fscache bit waiting functions are completely crazy. The comment
about "this will wake up others" is actively wrong, and the waiting
function looks insane, because you're mixing the two names for
"fscache" which makes the code look totally incomprehensible. Why
would we wait for PF_fscache, when PG_private_2 was set? Yes, I know
why, but the code looks entirely nonsensical.

So just looking at the support infrastructure changes, I get a big "Hmm".

But the thing that makes me go "No, I won't pull this", is that it has
all the same hallmark signs of trouble that I've complained about
before: I see absolutely zero sign of "this has more developers
involved".

There's not a single ack from a VM person for the VM changes. There's
no sign that this isn't yet another "David Howells went off alone and
did something that absolutely nobody else cared about".

See my problem? I need to be convinced that this makes sense outside
of your world, and it's not yet another thing that will cause problems
down the line because nobody else really ever used it or cared about
it until we hit a snag.

                  Linus