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From:   Michal Suchanek <msuchanek@suse.de>
To:     linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org
Cc:     Michal Suchanek <msuchanek@suse.de>,
        "Theodore Ts'o" <tytso@mit.edu>,
        Andreas Dilger <adilger.kernel@dilger.ca>,
        "Darrick J. Wong" <darrick.wong@oracle.com>,
        Ira Weiny <ira.weiny@intel.com>, Jan Kara <jack@suse.cz>,
        linux-kernel@vger.kernel.org
Subject: [PATCH 0/2] Tristate moount option comatibility fixup
Date:   Mon,  9 Nov 2020 20:10:07 +0100
Message-Id: <cover.1604948373.git.msuchanek@suse.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Hello,

after the tristate dax option change some applications fail to detect
pmem devices because the dax option no longer shows in mtab when device
is mounted with -o dax.

At first it might seem stupid to detect pmem by looking at the mount
options.

However, if the application actually wants a mount point properly
configured for dax rather than just backed by pmem I do not see any
other easy way.

Also this happens during early installtion steps when the mounted
filesystem is typically empty and you want to perform non-destructive
detection.

If there are better ways to detect dax enabled mount poins I want to
hear all about it. In the meantime we have legacy applications to
support.

It also makes sense that when you mount a device with -o dax it actually
shows dax in the mount options. Not doind so is confusing for humans as
well.

Thanks

Michal

Michal Suchanek (2):
  xfs: show the dax option in mount options.
  ext4: show the dax option in mount options

References: bsc#1178366

 fs/ext4/super.c    | 2 +-
 fs/xfs/xfs_super.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

-- 
2.26.2