Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 20 Sep 2022 04:30:16 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Daniil Lunev <dlunev@google.com>
Cc:     Christoph Hellwig <hch@infradead.org>,
        Sarthak Kukreti <sarthakkukreti@chromium.org>,
        Stefan Hajnoczi <stefanha@redhat.com>, dm-devel@redhat.com,
        linux-block@vger.kernel.org, linux-ext4@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        virtualization@lists.linux-foundation.org,
        Jens Axboe <axboe@kernel.dk>,
        "Michael S . Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Alasdair Kergon <agk@redhat.com>,
        Mike Snitzer <snitzer@kernel.org>,
        Theodore Ts'o <tytso@mit.edu>,
        Andreas Dilger <adilger.kernel@dilger.ca>,
        Bart Van Assche <bvanassche@google.com>,
        Evan Green <evgreen@google.com>,
        Gwendal Grignou <gwendal@google.com>
Subject: Re: [PATCH RFC 0/8] Introduce provisioning primitives for thinly
 provisioned storage
Message-ID: <YymkSDsFVVg1nbDP@infradead.org>
References: <20220915164826.1396245-1-sarthakkukreti@google.com>
 <YyQTM5PRT2o/GDwy@fedora>
 <CAG9=OMPHZqdDhX=M+ovdg5fa3x4-Q_1r5SWPa8pMTQw0mr5fPg@mail.gmail.com>
 <Yylvvm3zVgqpqDrm@infradead.org>
 <CAAKderPF5Z5QLxyEb80Y+90+eR0sfRmL-WfgXLp=eL=HxWSZ9g@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAAKderPF5Z5QLxyEb80Y+90+eR0sfRmL-WfgXLp=eL=HxWSZ9g@mail.gmail.com>
Precedence: bulk

On Tue, Sep 20, 2022 at 08:17:10PM +1000, Daniil Lunev wrote:
> to WRITE ZERO command in NVMe, but to WRITE UNAVAILABLE in

There is no such thing as WRITE UNAVAILABLE in NVMe.

> NVME 2.0 spec, and to UNMAP ANCHORED in SCSI spec.

The SCSI anchored LBA state is quite complicated, and in addition
to UNMAP you can also create it using WRITE SAME, which is at least
partially useful, as it allows for sensible initialization pattern.
For the purpose of Linux that woud be 0.

That being siad you still haven't actually explained what problem
you're even trying to solve.