On Wed, Jun 25, 2025 at 1:07 AM NeilBrown <neil@xxxxxxxxxx> wrote: > > This series of patches for overlayfs is primarily focussed on preparing > for some proposed changes to directory locking. In the new scheme we > wil lock individual dentries in a directory rather than the whole > directory. > > ovl currently will sometimes lock a directory on the upper filesystem > and do a few different things while holding the lock. This is > incompatible with the new scheme. > > This series narrows the region of code protected by the directory lock, > taking it multiple times when necessary. This theoretically open up the > possibilty of other changes happening on the upper filesytem between the > unlock and the lock. To some extent the patches guard against that by > checking the dentries still have the expect parent after retaking the > lock. In general, I think ovl would have trouble if upperfs were being > changed independantly, and I don't think the changes here increase the > problem in any important way. > > The first patch in this series doesn't exactly match the above, but it > does relate to directory locking and I think it is a sensible > simplificaiton. > > I have tested this with fstests, both generic and unionfs tests. I > wouldn't be surprised if I missed something though, so please review > carefully. Can you share a git branch for me to pull and test? Thanks, Amir.
