From: Dan Williams <dan.j.williams@intel.com>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Jan Kara <jack@suse.cz>, linux-nvdimm <linux-nvdimm@lists.01.org>,
Dave Chinner <david@fromorbit.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-xfs <linux-xfs@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v6 12/15] xfs: require mmap lock for xfs_break_layouts()
Date: Mon, 19 Mar 2018 10:57:55 -0700 [thread overview]
Message-ID: <CAPcyv4hsLSR=eG8=yLtOhrOaUjqjV5S8pwwmP3oOLrknWQS6Mg@mail.gmail.com> (raw)
In-Reply-To: <20180319173345.GF1757@magnolia>
On Mon, Mar 19, 2018 at 10:33 AM, Darrick J. Wong
<darrick.wong@oracle.com> wrote:
> On Thu, Mar 15, 2018 at 08:52:29AM -0700, Dan Williams wrote:
>> In preparation for adding coordination between truncate operations and
>> busy dax-pages, extend xfs_break_layouts() to assume it must be called
>> with the mmap lock held. This locking scheme will be required for
>> coordinating the break of 'dax layouts' (non-idle dax (ZONE_DEVICE)
>> pages mapped into the file's address space).
>
> If I'm reading this right, you've added a requirement (for xfs anyway)
> that we have to have grabbed MMAPLOCK_EXCL before calling break_layout()
> so that the layout breaking process will block until active dmas have
> finished.
>
> In 4.16 we added xfs_iolock_two_inodes_and_break_layout (in
> xfs_reflink.c) to break pnfs leases for files that are about to be
> reflinked (since pnfs and reflink aren't compatible either). I think
> that function will have to be adapted to take the appropriate mmap locks
> too -- definitely the exclusive mmap lock for the destination file
> because we anticipate punching out blocks. I'm not sure about the
> source file; I think taking the shared mmap lock is fine for that?
I don't see anything to adapt with respect to mmap locks since reflink
and dax are mutually exclusive. The new lock coordination and layout
breaking in xfs_break_dax_layouts() only applies to dax vs truncate,
so xfs_iolock_two_inodes_and_break_layout() looks ok to me as is.
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next prev parent reply other threads:[~2018-03-19 17:51 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-15 15:51 [PATCH v6 00/15] dax: fix dma vs truncate/hole-punch Dan Williams
2018-03-15 15:51 ` [PATCH v6 01/15] dax: store pfns in the radix Dan Williams
2018-03-15 15:51 ` [PATCH v6 02/15] fs, dax: prepare for dax-specific address_space_operations Dan Williams
2018-03-16 18:59 ` Christoph Hellwig
2018-03-15 15:51 ` [PATCH v6 03/15] block, dax: remove dead code in blkdev_writepages() Dan Williams
2018-03-16 18:59 ` Christoph Hellwig
2018-03-15 15:51 ` [PATCH v6 04/15] xfs, dax: introduce xfs_dax_aops Dan Williams
2018-03-16 19:00 ` Christoph Hellwig
2018-03-15 15:51 ` [PATCH v6 05/15] ext4, dax: introduce ext4_dax_aops Dan Williams
2018-03-15 15:51 ` [PATCH v6 06/15] ext2, dax: introduce ext2_dax_aops Dan Williams
2018-03-18 4:02 ` kbuild test robot
2018-03-18 4:02 ` [RFC PATCH] ext2, dax: ext2_dax_aops can be static kbuild test robot
2018-03-15 15:52 ` [PATCH v6 07/15] fs, dax: use page->mapping to warn if truncate collides with a busy page Dan Williams
2018-03-18 6:26 ` kbuild test robot
2018-03-15 15:52 ` [PATCH v6 08/15] mm, dax: enable filesystems to trigger dev_pagemap ->page_free callbacks Dan Williams
2018-03-15 15:52 ` [PATCH v6 09/15] mm, dev_pagemap: introduce CONFIG_DEV_PAGEMAP_OPS Dan Williams
2018-03-15 15:52 ` [PATCH v6 10/15] memremap: mark devm_memremap_pages() EXPORT_SYMBOL_GPL Dan Williams
2018-03-15 15:52 ` [PATCH v6 11/15] mm, fs, dax: handle layout changes to pinned dax mappings Dan Williams
2018-03-16 19:01 ` Christoph Hellwig
2018-03-17 22:14 ` kbuild test robot
2018-03-15 15:52 ` [PATCH v6 12/15] xfs: require mmap lock for xfs_break_layouts() Dan Williams
2018-03-16 19:04 ` Christoph Hellwig
2018-03-16 19:10 ` Dan Williams
2018-03-19 17:33 ` Darrick J. Wong
2018-03-19 17:57 ` Dan Williams [this message]
2018-03-19 18:19 ` Darrick J. Wong
2018-03-19 18:34 ` Dan Williams
2018-03-19 19:45 ` Christoph Hellwig
2018-03-19 20:10 ` Dan Williams
2018-03-19 21:14 ` Christoph Hellwig
2018-03-15 15:52 ` [PATCH v6 13/15] xfs: communicate lock drop events from xfs_break_layouts() Dan Williams
2018-03-16 19:08 ` Christoph Hellwig
2018-03-15 15:52 ` [PATCH v6 14/15] xfs: prepare xfs_break_layouts() for another layout type Dan Williams
2018-03-16 19:08 ` Christoph Hellwig
2018-03-19 17:45 ` Darrick J. Wong
2018-03-19 18:09 ` Dan Williams
2018-03-15 15:52 ` [PATCH v6 15/15] xfs, dax: introduce xfs_break_dax_layouts() Dan Williams
2018-03-16 19:09 ` Christoph Hellwig
2018-03-17 22:11 ` kbuild test robot
2018-03-17 23:47 ` kbuild test robot
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