Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Christoph Hellwig <hch@lst.de>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     Justin Sanders <justin@coraid.com>,
        Josef Bacik <josef@toxicpanda.com>,
        Xianting Tian <xianting_tian@126.com>,
        linux-block@vger.kernel.org, dm-devel@redhat.com,
        Stefan Haberland <sth@linux.ibm.com>,
        Jan Hoeppner <hoeppner@linux.ibm.com>,
        linux-kernel@vger.kernel.org, nbd@other.debian.org,
        linux-nvme@lists.infradead.org, linux-s390@vger.kernel.org
Subject: fix block device size update serialization v2
Date:   Sun, 23 Aug 2020 11:10:40 +0200
Message-Id: <20200823091043.2600261-1-hch@lst.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi Jens,

this series fixes how we update i_size for the block device inodes (and
thus the block device).  Different helpers use two different locks
(bd_mutex and i_rwsem) to protect the update, and it appears device
mapper uses yet another internal lock.  A lot of the drivers do the
update handcrafted in often crufty ways.  And in addition to that mess
it turns out that the "main" lock, bd_mutex is pretty dead lock prone
vs other spots in the block layer that acquire it during revalidation
operations, as reported by Xianting.

Fix all that by adding a dedicated spinlock just for the size updates.

Changes since v1:
 - don't call __invalidate_device under the new spinlock
 - don't call into the file system code from the nvme removal code