linux-fsdevel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
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 3/7] dm: fix test for DAX device support
Date: Tue, 29 May 2018 13:51:02 -0600	[thread overview]
Message-ID: <20180529195106.14268-4-ross.zwisler@linux.intel.com> (raw)
In-Reply-To: <20180529195106.14268-1-ross.zwisler@linux.intel.com>

Currently device_supports_dax() just checks to see if the QUEUE_FLAG_DAX
flag is set on the device's request queue to decide whether or not the
device supports filesystem DAX.  This is insufficient because there are
devices like PMEM namespaces in raw mode which have QUEUE_FLAG_DAX set but
which don't actually support DAX.

This means that you could create a dm-linear device, for example, where the
first part of the dm-linear device was a PMEM namespace in fsdax mode and
the second part was a PMEM namespace in raw mode.  Both DM and the
filesystem you put on that dm-linear device would think the whole device
supports DAX, which would lead to bad behavior once your raw PMEM namespace
part using DAX needed struct page for something.

Fix this by using bdev_dax_supported() like filesystems do at mount time.
This checks for raw mode and also performs other tests like checking to
make sure the dax_direct_access() path works.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Fixes: commit 545ed20e6df6 ("dm: add infrastructure for DAX support")
---
 drivers/md/dm-table.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 0589a4da12bb..5bb994b012ca 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -885,9 +885,7 @@ EXPORT_SYMBOL_GPL(dm_table_set_type);
 static int device_supports_dax(struct dm_target *ti, struct dm_dev *dev,
 			       sector_t start, sector_t len, void *data)
 {
-	struct request_queue *q = bdev_get_queue(dev->bdev);
-
-	return q && blk_queue_dax(q);
+	return bdev_dax_supported(dev->bdev, PAGE_SIZE);
 }
 
 static bool dm_table_supports_dax(struct dm_table *t)
-- 
2.14.3

  parent 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 [PATCH v2 0/7] Fix DM DAX handling Ross Zwisler
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 ` Ross Zwisler [this message]
2018-06-01 20:19   ` [PATCH v2 3/7] dm: fix test for DAX device support 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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180529195106.14268-4-ross.zwisler@linux.intel.com \
    --to=ross.zwisler@linux.intel.com \
    --cc=dm-devel@redhat.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=linux-xfs@vger.kernel.org \
    --cc=snitzer@redhat.com \
    --cc=toshi.kani@hpe.com \
    --subject='Re: [PATCH v2 3/7] dm: fix test for DAX device support' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).