On Wed, Apr 28, 2021 at 12:14:42AM -0700, Linus Torvalds wrote: > Of course, %pD has some other limitations too. It doesn't follow > mount-points up. It's kind of intentionally a "for simple > informational uses only", but good enough in practice exactly for > things like debug printouts. Which thinking about my testing is probably the real problem. When running xfstests the it only printed "swap" as the file name, as the tests create it under the rest mount points. Which really is of not use. While printing /fstests/scratch/swap actually is useful. I suspect the s390 issue with the hardcoded "/dev/" prefix is somewhat similar.