> On Apr 7, 2021, at 8:58 PM, Olga Kornievskaia <olga.kornievskaia@xxxxxxxxx> wrote: > > Furthermore, I still really would like Bruce or Chuck to weigh in on > the use of the semaphore. The semaphore caught my eye too. The usual trick to prevent a mount from disappearing is to bump a reference count until it is safe for the mount to possibly go away. Dai, if you can make this work with just an extra reference count, I would prefer that. > We are holding onto a semaphore while doing > vfs_kern_mount(), I thought it's frowned upon to hold any locks while > doing network operations. What if vfs_kern_mount() is trying to reach > an unresponsive server, then all other unmount are blocked, right? I > still don't understand why we need a semaphore. I think a spin lock > that protects access to the list of umounts is sufficient. I probably > should be commenting on the actual patch here. -- Chuck Lever
