On Fri, Aug 11, 2023 at 4:06 PM Miklos Szeredi <miklos@xxxxxxxxxx> wrote: > > On Thu, 20 Jul 2023 at 17:37, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > > > > Hi Miklos, > > > > These prep patches are needed for my start-write-safe series [1]. > > This is not urgent and the prep patches don't need to be merged > > for next cycle, but I think these are good changes regardless, > > so wanted to post them for early review - if you like them you can > > queue them for 6.6. > > > > It is quite hard to do the review of the locking reorder patch from the > > diff itself and I couldn't figure out a better way to split this change. > > I've intentionally left some otherwise useless out: goto labels to > > make the patch review a bit simper - they could be removed later. > > > > On the good side, lockdep was very tough with me and it easily detected > > bugs in the earlier versions of the patches. > > > > Going on vacation. will be back round rc6. > > > > Thanks, > > Amir. > > > > [1] https://github.com/amir73il/linux/commits/start-write-safe > > > > Amir Goldstein (2): > > ovl: reorder ovl_want_write() after ovl_inode_lock() > > This one generally looks good. The failure paths will need careful > review, because those are usually not exercised by the test suites. > > > ovl: avoid lockdep warning with open and llseek of lower file > > But I dislike this one. Seems like a bad workaround for a possibly > non-issue. I understand the desire to silence lockdep, but surely we > can do better. Well, I didn't do it to silence lockdep. I did it as a prereq for start-write-safe fsnotify hooks (see [1] above). Silencing lockdep is an added bonus that I observed along the way. v2 [2] has a less hacky, but more noisy version of this patch which minimizes the scope of ovl_want_write() to when we need it. Let me know if this is what you had in mind. After looking more closely, I found another possible deadlock with nested overlay, which I think is real and added another commit to fix it. [2] https://github.com/amir73il/linux/commits/ovl_want_write-v2 Thanks, Amir.
