On Thu, Oct 01, 2015 at 02:31:21PM -0600, Ross Zwisler wrote: > On Thu, Oct 01, 2015 at 05:46:32PM +1000, Dave Chinner wrote: > > Hi folks, > > > > As discussed in the recent thread about problems with DAX locking: > > > > http://www.gossamer-threads.com/lists/linux/kernel/2264090?do=post_view_threaded > > > > I said that I'd post the patch set that fixed the problems for XFS > > as soon as I had something sane and workable. That's what this > > series is. > > > > To start with, it passes xfstests "auto" group with only the only > > failures being expected failures or failures due to unexpected > > allocation patterns or trying to use unsupported block sizes. That > > makes it better than any previous version of the XFS/DAX code. ..... > Thank you for working on this, and for documenting your thinking so clearly. To put this in perspective, "patch 0" descriptions like this is a requirement for any non-trivial XFS modification. It saves reviewers so much time and many round trips in email and IRC to understand the changes being proposed that it's a no-brainer. Lead by example, and all that... > One thing I noticed is that in my test setup XFS+DAX is now failing > generic/274: > > # diff -u tests/generic/274.out /root/xfstests/results//generic/274.out.bad > --- tests/generic/274.out 2015-08-24 11:05:41.490926305 -0600 > +++ /root/xfstests/results//generic/274.out.bad 2015-10-01 13:53:50.498354091 -0600 > @@ -2,4 +2,5 @@ > ------------------------------ > preallocation test > ------------------------------ > -done > +failed to write to test file > +(see /root/xfstests/results//generic/274.full for details) > > I've verified that the test passes 100% of the time with my baseline > (v4.3-rc3), and with the set applied but without the DAX mount option. With > the series and with DAX it fails 100% of the time. I haven't looked into the > details of the failure yet, I just wanted to let you know that it was > happening. See above - I classified this under the "failures due to unexpected allocation patterns". This is a ENOSPC test, and we've change the allocation pattern and the unwritten extent conversion algorithm and so changed the metadata allocation demand of the test. I haven't looked any further than this yet, but I suspect the issue is that the up-front unwritten extent conversion is not being allowed to dip into the reserve block pool for BMBT allocations when the extent list grows past a single block. If that's the case, then it's a couple of lines of code to conditionally at XFS_TRANS_RESERVE to the transaction handle to allow it access to the reserve pool... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
