Amir Goldstein <amir73il@xxxxxxxxx> wrote: > Good idea, but then the helpers to set the flag should not be internal > to cachefiles and the locking semantics should be clear. I could move them out, at least partially. They do log some information that's private to cachefiles through the tracepoint, but it's just one number and could be passed in as a parameter. I could move the tracepoint to somewhere more generic. > FYI, overlayfs already takes an "exclusive lock" on upper/work dir > among all ovl instances. > > How do you feel about hoisting ovl_inuse_* helpers to fs.h > and rename s/I_OVL_INUSE/I_EXCL_INUSE? Fine by me. Sharing a cache with or through an overlay would make for very fun coherency management. > Whether deny rmdir should have its own flag or not I don't know, > but from ovl POV I *think* it should not be a problem to deny rmdir > for the ovl upper/work dirs as long as ovl is mounted(?). What's the consequence of someone rearranging the directories directly in the contributing dirs whilst there's an overlay over them? > Another problem with generic deny of rmdir is that users getting > EBUSY have no way to figure out the reason. > At least for a specific subsystem (i.e. cachefiles) users should be able > to check if the denied dir is in the subsystem's inventory(?) I could add a tracepoint for that. It could form a set with the cachefiles tracepoints if I move those out too. David
