On Wed, Jun 28, 2023 at 11:02 AM Tejun Heo <tj@xxxxxxxxxx> wrote: > > On Wed, Jun 28, 2023 at 07:35:20PM +0200, Christian Brauner wrote: > > > To summarize my understanding of your proposal, you suggest adding new > > > kernfs_ops for the case you marked (1) and change ->release() to do > > > only (2). Please correct me if I misunderstood. Greg, Tejun, WDYT? > > > > Yes. I can't claim to know all the intricate implementation details of > > kernfs ofc but this seems sane to me. > > This is going to be massively confusing for vast majority of kernfs users. > The contract kernfs provides is that you can tell kernfs that you want out > and then you can do so synchronously in a finite amount of time (you still > have to wait for in-flight operations to finish but that's under your > control). Adding an operation which outlives that contract as something > usual to use is guaranteed to lead to obscure future crnashes. For a > temporary fix, it's fine as long as it's marked clearly but please don't > make it something seemingly widely useable. > > We have a long history of modules causing crashes because of this. The > severing semantics is not there just for fun. I'm sure there are reasons things are working as they do today. Sounds like we can't change the ->release() logic from what it is today... Then the question is how do we fix this case needing to release a resource which can be released only when there are no users of the file? My original suggestion was to add a kernfs_ops operation which would indicate there are no more users but that seems to be confusing. Are there better ways to fix this issue? Thanks, Suren. > > Thanks. > > -- > tejun
