commit 9f4736fe7ca804aa79b5916221bb13dfc6221a0f
author Dan Williams <dan.j.williams@intel.com> Thu Jan 28 20:13:39 2016 -0800
committer Dan Williams <dan.j.williams@intel.com> Sat Jan 30 13:35:31 2016 -0800
tree 1604ce0292634817892790f0eb8cdb0e1821de1e
parent 65f87ee71852a754f7981d0653e7136039b8798a

block: revert runtime dax control of the raw block device

Dynamically enabling DAX requires that the page cache first be flushed
and invalidated.  This must occur atomically with the change of DAX mode
otherwise we confuse the fsync/msync tracking and violate data
durability guarantees.  Eliminate the possibilty of DAX-disabled to
DAX-enabled transitions for now and revisit this for the next cycle.

Cc: Jan Kara <jack@suse.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>