Hi Ted, On Sat, May 01, 2021 at 03:56:23PM -0400, Theodore Ts'o wrote: > I tried running xfstests against the spf branch, and I've noticed it's > causing regression for generic/619. It's failing due to a umount > failure due to a busy mount point: > > QA output created by 619 > umount: /vdc: target is busy. > > I haven't had a chance to investigate, but I thought I should let you know. Thanks for the report. I think the issue is likely caused by commit 06adfeb8150d "mm: rcu safe vma->vm_file freeing", which will defer fput on mapped files for one rcu grace period. I expect adding synchronize_rcu to the proper place (I'm not sure exactly where though) when unmounting file systems would be a workable fix. Note though - at this point I am only submitting the anon part of the patchset for inclusion. That is, the v5.12-spf-anon branch, rather than the v5.12-spf branch which has the additional / less mature changes for file mapped vma faults. -- Michel "walken" Lespinasse
