In the last couple days I've started getting hangs on xfstests generic/186 on upstream. I also notice the test completes after 10+ hours (usually it takes about 5 minutes). Sometimes this is accompanied by "nfs: RPC call returned error 12" on the client. Test description is: # Ensuring that copy on write in buffered mode works when free space # is heavily fragmented. # - Create two files # - Reflink the odd blocks of the first file into a third file. # - Reflink the even blocks of the second file into the third file. # - Try to fragment the free space by allocating a huge file and # punching out every other block. # - CoW across the halfway mark. # - Check that the files are now different where we say they're # different. so maybe it's really some xfs change, I don't know. Or maybe it's a problem with my particular test filesystem (which doesn't get recreated for each test run). The problem doesn't reproduce easily enough to bisect. I may just turn off that test for now. --b.