Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > - it would be much better if you could incrementally just improve the > existing FSCACHE so that it just _works_ all the time, and fixes the > problems in it, and a bisection works, and there is no flag-day. As I stated in the cover letters, the advent of the kiocb and tmpfile interfaces provide a way to massively simplify the way fscache and cachefiles work - and, as a result, remove over five thousand lines of code. With the changes I'm looking at making, I can get rid of the object state machine as it stands and the operation scheduling - which means all of the code in: fs/fscache/object.c fs/fscache/operation.c gets deleted along with: fs/fscache/page.c fs/cachefiles/rdwr.c when I remove the deprecated I/O code (which is what this patchset does). A large chunk of code in fs/fscache/cookie.c gets removed and replaced too Further, I've been looking at simplifying the index management with an eye to completely replacing the cache backend with something more akin to a tagged cache with fixed-size storage units. This also allows the cachefiles code to be simplified a bit too. This means bisection is of limited value and why I'm looking at a 'flag day'. There is one particular problem that *this* patchset was intended to address: I want to convert the filesystems that are going to be accessing fscache to use netfslib, but they're not all there yet so that there's one common body of code that does VM interface, cache I/O and content crypto (eg. fscrypt). Jeff and I have converted afs and ceph already and I've got a conversion for 9p in this patchset. I have a partial patch for cifs/smb and have been discussing that with Steve and Shyam. Dave Wysochanski has a set of patches for nfs, but there's pushback on it from the nfs maintainers. This particular patchset is intended to enable removal of the old I/O routines by changing nfs and cifs to use a "fallback" method to use the new kiocb-using API and thus allow me to get on with the rest of it. However, if you would rather I just removed all of fscache and (most of[*]) cachefiles, that I can do. I have the patches arrayed in a way that makes them easier to explain logically and, hopefully, easier to review. It would, however, leave any netfs that isn't converted to use netfslib unable to use caching until converted. David [*] The code that deals with the cachefilesd UAPI will be mostly unchanged.
