Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: don't use ->bd_inode to access the block device size v3
To:     Christoph Hellwig <hch@lst.de>
Cc:     Coly Li <colyli@suse.de>, Mike Snitzer <snitzer@redhat.com>,
        Song Liu <song@kernel.org>, David Sterba <dsterba@suse.com>,
        Josef Bacik <josef@toxicpanda.com>,
        Theodore Ts'o <tytso@mit.edu>,
        OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>,
        Dave Kleikamp <shaggy@kernel.org>,
        Ryusuke Konishi <konishi.ryusuke@gmail.com>,
        Anton Altaparmakov <anton@tuxera.com>,
        Konstantin Komarov <almaz.alexandrovich@paragon-software.com>,
        Kees Cook <keescook@chromium.org>,
        Phillip Lougher <phillip@squashfs.org.uk>,
        Jan Kara <jack@suse.com>, linux-block@vger.kernel.org,
        dm-devel@redhat.com, drbd-dev@lists.linbit.com,
        linux-bcache@vger.kernel.org, linux-raid@vger.kernel.org,
        linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org,
        target-devel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org,
        jfs-discussion@lists.sourceforge.net, linux-nfs@vger.kernel.org,
        linux-nilfs@vger.kernel.org, linux-ntfs-dev@lists.sourceforge.net,
        ntfs3@lists.linux.dev, reiserfs-devel@vger.kernel.org
References: <20211018101130.1838532-1-hch@lst.de>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <4a8c3a39-9cd3-5b2f-6d0f-a16e689755e6@kernel.dk>
Date:   Mon, 18 Oct 2021 11:16:08 -0600
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.10.0
MIME-Version: 1.0
In-Reply-To: <20211018101130.1838532-1-hch@lst.de>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 10/18/21 4:11 AM, Christoph Hellwig wrote:
> Hi Jens,
> 
> various drivers currently poke directy at the block device inode, which
> is a bit of a mess.  This series cleans up the places that read the
> block device size to use the proper helpers.  I have separate patches
> for many of the other bd_inode uses, but this series is already big
> enough as-is,

This looks good to me. Followup question, as it's related - I've got a
hacky patch that caches the inode size in the bdev:

https://git.kernel.dk/cgit/linux-block/commit/?h=perf-wip&id=c754951eb7193258c35a574bd1ccccb7c4946ee4

so we don't have to dip into the inode itself for the fast path. While
it's obviously not something being proposed for inclusion right now, is
there a world in which we can make something like that work?

-- 
Jens Axboe