From: Dan Williams <dan.j.williams@intel.com>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Shiyang Ruan <ruansy.fnst@fujitsu.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-xfs <linux-xfs@vger.kernel.org>,
Linux NVDIMM <nvdimm@lists.linux.dev>,
Linux MM <linux-mm@kvack.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
david <david@fromorbit.com>,
Christoph Hellwig <hch@infradead.org>,
Jane Chu <jane.chu@oracle.com>
Subject: Re: [PATCH v9 02/10] dax: Introduce holder for dax_device
Date: Wed, 5 Jan 2022 16:12:04 -0800 [thread overview]
Message-ID: <CAPcyv4gUmpDnGkhd+WdhcJVMP07u+CT8NXRjzcOTp5KF-5Yo5g@mail.gmail.com> (raw)
In-Reply-To: <20220105235407.GN656707@magnolia>
On Wed, Jan 5, 2022 at 3:54 PM Darrick J. Wong <djwong@kernel.org> wrote:
[..]
> > Yes, I think we should just fail the holder registration and
> > DAX+reflink unless the FS being mounted on a whole device. I know Ted
> > and others had reservations about moving filesystems to be mounted on
> > dax-devices directly, but hopefully the whole-block_device requirement
> > is a workable middle ground?
>
> I think you have to be /very/ careful about that kind of statement --
>
> Take ext4 for example. It has a lot of statically allocated ondisk
> metadata. Someone could decide that it's a good idea to wire up a media
> failure notification so that we shut down the fs if (say) a giant hole
> opens up in the middle of the inode table. However, registering any
> kind of media failure handler brings along this requirement for not
> having partitions.
>
> This means that if ext4 finds a filesystem on a partition on a pmem
> device and someone else has already registered a media failure handler,
> it will have to choose between foregoing media failure notifications or
> failing the mount outright.
...good example.
> Or you could support notification call chains...
We ended up with explicit callbacks after hch balked at a notifier
call-chain, but I think we're back to that now. The partition mistake
might be unfixable, but at least bdev_dax_pgoff() is dead. Notifier
call chains have their own locking so, Ruan, this still does not need
to touch dax_read_lock().
next prev parent reply other threads:[~2022-01-06 0:12 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-26 14:34 [PATCH v9 00/10] fsdax: introduce fs query to support reflink Shiyang Ruan
2021-12-26 14:34 ` [PATCH v9 01/10] dax: Use percpu rwsem for dax_{read,write}_lock() Shiyang Ruan
2022-01-04 22:44 ` Dan Williams
2022-01-05 17:45 ` Darrick J. Wong
2022-01-06 11:06 ` Shiyang Ruan
2021-12-26 14:34 ` [PATCH v9 02/10] dax: Introduce holder for dax_device Shiyang Ruan
2022-01-05 18:12 ` Darrick J. Wong
2022-01-05 18:23 ` Dan Williams
2022-01-05 18:56 ` Darrick J. Wong
2022-01-05 19:20 ` Dan Williams
2022-01-05 22:47 ` Darrick J. Wong
2022-01-05 23:01 ` Dan Williams
2022-01-05 23:54 ` Darrick J. Wong
2022-01-06 0:12 ` Dan Williams [this message]
2022-01-20 8:46 ` Christoph Hellwig
2022-01-21 1:26 ` Shiyang Ruan
2022-01-21 2:22 ` Darrick J. Wong
2022-01-21 7:17 ` Christoph Hellwig
2022-02-15 21:51 ` Dan Williams
2021-12-26 14:34 ` [PATCH v9 03/10] mm: factor helpers for memory_failure_dev_pagemap Shiyang Ruan
2021-12-26 14:34 ` [PATCH v9 04/10] pagemap,pmem: Introduce ->memory_failure() Shiyang Ruan
2022-01-05 19:06 ` Darrick J. Wong
2021-12-26 14:34 ` [PATCH v9 05/10] fsdax: fix function description Shiyang Ruan
2022-01-05 17:50 ` Darrick J. Wong
2022-01-20 8:47 ` Christoph Hellwig
2021-12-26 14:34 ` [PATCH v9 06/10] fsdax: Introduce dax_lock_mapping_entry() Shiyang Ruan
2022-01-04 22:55 ` Dan Williams
2021-12-26 14:34 ` [PATCH v9 07/10] mm: move pgoff_address() to vma_pgoff_address() Shiyang Ruan
2022-01-20 8:47 ` Christoph Hellwig
2021-12-26 14:34 ` [PATCH v9 08/10] mm: Introduce mf_dax_kill_procs() for fsdax case Shiyang Ruan
2022-01-20 8:55 ` Christoph Hellwig
2021-12-26 14:34 ` [PATCH v9 09/10] xfs: Implement ->notify_failure() for XFS Shiyang Ruan
2022-01-05 18:53 ` Darrick J. Wong
2022-01-05 21:17 ` Dan Williams
2021-12-26 14:34 ` [PATCH v9 10/10] fsdax: set a CoW flag when associate reflink mappings Shiyang Ruan
2022-01-20 8:59 ` Christoph Hellwig
2022-01-21 2:33 ` Shiyang Ruan
2022-01-21 7:16 ` Christoph Hellwig
2022-01-21 8:34 ` Shiyang Ruan
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