On Fri, Sep 08, 2017 at 12:20:28AM -0700, Christoph Hellwig wrote: > On Thu, Sep 07, 2017 at 03:08:31PM -0600, Ross Zwisler wrote: > > Before support for the per-inode DAX flag was disabled the XFS the code had > > an issue where the user couldn't reliably tell whether or not DAX was being > > used to service page faults and I/O when the DAX mount option was used. In > > this case each inode within the mounted filesystem started with S_DAX set > > due to the mount option, but it could be cleared if someone touched the > > individual inode flag. > > Looks good, but can you please add a testcase to xfstests for this? Hmm...aside from looking at tracepoints, I'm not sure how to detect whether or not S_DAX is actually being used for an inode. I don't see any other xfstests that try and look at the trace buffer, but I guess that could work. Do you know of a better way to detect this test failure/success? > Reviewed-by: Christoph Hellwig <hch@xxxxxx> Thanks for the review!