On Tue, Jun 02, 2020 at 09:58:52AM -0700, Darrick J. Wong wrote: > Hi Linus, > > After many years of LKML-wrangling about how to enable programs to query > and influence the file data access mode (DAX) when a filesystem resides > on storage devices such as persistent memory, Ira Weiny has emerged with > a proposed set of standard behaviors that has not been shot down by > anyone! We're more or less standardizing on the current XFS behavior > and adapting ext4 to do the same. Also, for those interested: The corresponding man page change mentioned in the commit has been submitted here: https://lore.kernel.org/lkml/20200505002016.1085071-1-ira.weiny@xxxxxxxxx/ Ira > > This pull request is the first of a handful that will make ext4 and XFS > present a consistent interface for user programs that care about DAX. > We add a statx attribute that programs can check to see if DAX is > enabled on a particular file. Then, we update the DAX documentation to > spell out the user-visible behaviors that filesystems will guarantee > (until the next storage industry shakeup). The on-disk inode flag has > been in XFS for a few years now. > > Note that Stephen Rothwell reported a minor merge conflict[1] between > the first cleanup patch and a different change in the block layer. The > resolution looks pretty straightforward, but let me know if you > encounter problems. > > --D > > [1] https://lore.kernel.org/linux-next/20200522145848.38cdcf54@xxxxxxxxxxxxxxxx/ > > The following changes since commit 0e698dfa282211e414076f9dc7e83c1c288314fd: > > Linux 5.7-rc4 (2020-05-03 14:56:04 -0700) > > are available in the Git repository at: > > git://git.kernel.org/pub/scm/fs/xfs/xfs-linux.git tags/vfs-5.8-merge-1 > > for you to fetch changes up to 83d9088659e8f113741bb197324bd9554d159657: > > Documentation/dax: Update Usage section (2020-05-04 08:49:39 -0700) > > ---------------------------------------------------------------- > New code for 5.8: > - Clean up io_is_direct. > - Add a new statx flag to indicate when file data access is being done > via DAX (as opposed to the page cache). > - Update the documentation for how system administrators and application > programmers can take advantage of the (still experimental DAX) feature. > > ---------------------------------------------------------------- > Ira Weiny (3): > fs: Remove unneeded IS_DAX() check in io_is_direct() > fs/stat: Define DAX statx attribute > Documentation/dax: Update Usage section > > Documentation/filesystems/dax.txt | 142 +++++++++++++++++++++++++++++++++++++- > drivers/block/loop.c | 6 +- > fs/stat.c | 3 + > include/linux/fs.h | 7 +- > include/uapi/linux/stat.h | 1 + > 5 files changed, 147 insertions(+), 12 deletions(-)
