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From: Ross Zwisler <ross.zwisler@linux.intel.com>
To: Toshi Kani <toshi.kani@hpe.com>,
	Mike Snitzer <snitzer@redhat.com>,
	dm-devel@redhat.com
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-nvdimm@lists.01.org, linux-xfs@vger.kernel.org
Subject: [PATCH v2 0/7] Fix DM DAX handling
Date: Tue, 29 May 2018 13:50:59 -0600	[thread overview]
Message-ID: <20180529195106.14268-1-ross.zwisler@linux.intel.com> (raw)

Changes from v1:
 * Reworked patches 1 and 2 so that the __bdev_dax_supported() function
   stays hidden behind the bdev_dax_supported() wrapper.  This is needed
   to prevent compilation errors in configs where CONFIG_FS_DAX isn't
   defined. (0-day)

 * Added Eric's Reviewed-by to patch 1.  I did this in spite of the
   bdev_dax_supported() changes because they were minor and I think
   Eric's review was focused on the XFS parts.

---

This series fixes a few issues that I found with DM's handling of DAX
devices.  Here are some of the issues I found:

 * We can create a dm-stripe or dm-linear device which is made up of an
   fsdax PMEM namespace and a raw PMEM namespace but which can hold a
   filesystem mounted with the -o dax mount option.  DAX operations to
   the raw PMEM namespace part lack struct page and can fail in
   interesting/unexpected ways when doing things like fork(), examining
   memory with gdb, etc.

 * We can create a dm-stripe or dm-linear device which is made up of an
   fsdax PMEM namespace and a BRD ramdisk which can hold a filesystem
   mounted with the -o dax mount option.  All I/O to this filesystem
   will fail.

 * In DM you can't transition a dm target which could possibly support
   DAX (mode DM_TYPE_DAX_BIO_BASED) to one which can't support DAX
   (mode DM_TYPE_BIO_BASED), even if you never use DAX.

The first 2 patches in this series are prep work from Darrick and Dave
which improve bdev_dax_supported().  The last 5 problems fix the above
mentioned problems in DM.  I feel that this series simplifies the
handling of DAX devices in DM, and the last 5 DM-related patches have a
net code reduction of 50 lines.

Darrick J. Wong (1):
  fs: allow per-device dax status checking for filesystems

Dave Jiang (1):
  dax: change bdev_dax_supported() to support boolean returns

Ross Zwisler (5):
  dm: fix test for DAX device support
  dm: prevent DAX mounts if not supported
  dm: remove DM_TYPE_DAX_BIO_BASED dm_queue_mode
  dm-snap: remove unnecessary direct_access() stub
  dm-error: remove unnecessary direct_access() stub

 drivers/dax/super.c           | 40 ++++++++++++++++++++--------------------
 drivers/md/dm-ioctl.c         | 16 ++++++----------
 drivers/md/dm-snap.c          |  8 --------
 drivers/md/dm-table.c         | 29 +++++++++++------------------
 drivers/md/dm-target.c        |  7 -------
 drivers/md/dm.c               |  7 ++-----
 fs/ext2/super.c               |  3 +--
 fs/ext4/super.c               |  3 +--
 fs/xfs/xfs_ioctl.c            |  3 ++-
 fs/xfs/xfs_iops.c             | 30 +++++++++++++++++++++++++-----
 fs/xfs/xfs_super.c            | 10 ++++++++--
 include/linux/dax.h           | 11 ++++++-----
 include/linux/device-mapper.h |  8 ++++++--
 13 files changed, 88 insertions(+), 87 deletions(-)

-- 
2.14.3

             reply	other threads:[~2018-05-29 19:51 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-29 19:50 Ross Zwisler [this message]
2018-05-29 19:51 ` [PATCH v2 1/7] fs: allow per-device dax status checking for filesystems Ross Zwisler
2018-05-29 19:51 ` [PATCH v2 2/7] dax: change bdev_dax_supported() to support boolean returns Ross Zwisler
2018-05-29 21:25   ` Darrick J. Wong
2018-05-29 22:01     ` Ross Zwisler
2018-05-31 19:13       ` Darrick J. Wong
2018-05-31 20:34         ` Ross Zwisler
2018-05-31 20:35         ` Dan Williams
2018-05-31 20:41         ` Ross Zwisler
2018-05-31 20:52         ` Mike Snitzer
2018-05-31 22:26           ` [dm-devel] " Darrick J. Wong
2018-06-01 20:59             ` Ross Zwisler
2018-06-01  1:26         ` Dave Chinner
2018-06-01  1:57           ` Dan Williams
2018-06-01  2:24             ` Dave Chinner
2018-06-01  4:02               ` Dan Williams
2018-06-03 22:20                 ` Dave Chinner
2018-06-04  0:25                   ` Dave Chinner
2018-06-04  1:48                     ` Dan Williams
2018-06-04 23:40                       ` Dan Williams
2018-06-05  0:33                         ` Mike Snitzer
2018-06-05  5:55                           ` Dave Chinner
2018-06-05  3:32                         ` Dan Williams
2018-05-29 19:51 ` [PATCH v2 3/7] dm: fix test for DAX device support Ross Zwisler
2018-06-01 20:19   ` Mike Snitzer
2018-06-01 20:46     ` Mike Snitzer
2018-06-01 21:11       ` Ross Zwisler
2018-06-01 21:16       ` Dan Williams
2018-05-29 19:51 ` [PATCH v2 4/7] dm: prevent DAX mounts if not supported Ross Zwisler
2018-06-01 21:55   ` Mike Snitzer
2018-06-04 23:15     ` Ross Zwisler
2018-06-20 15:17       ` Mike Snitzer
2018-06-25 19:20         ` Ross Zwisler
2018-05-29 19:51 ` [PATCH v2 5/7] dm: remove DM_TYPE_DAX_BIO_BASED dm_queue_mode Ross Zwisler
2018-06-01 22:04   ` Mike Snitzer
2018-06-04 23:24     ` Ross Zwisler
2018-06-04 23:49       ` Kani, Toshi
2018-06-05  0:46       ` Mike Snitzer
2018-06-06 17:24         ` Ross Zwisler
2018-06-06 22:29           ` Mike Snitzer
2018-05-29 19:51 ` [PATCH v2 6/7] dm-snap: remove unnecessary direct_access() stub Ross Zwisler
2018-05-29 19:51 ` [PATCH v2 7/7] dm-error: " Ross Zwisler

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