Steve, List
A WIP patch series that starts preparing the open_shroot (now called
open_cached_dir) to be able to be used for any directory, not just root
by moving the checks for directory name ("") as well as the nohandlecache
mount option into the open_cached_dir() function.
Additionally, store, and take out a refcount, for both the dentry
for the root of the share as well as the directory we open in
open_cached_dir(). These two are the same right now but will start
to differ when we start using this for any directory, not just "".
And finally, do the final plumbing to check "is the lease still valid"
for the parent dirent when checking if we need to revalidate a dentry/inode
or not when called from (primarily) cifs_getattr().
This means that we can now safely serve attributes from out of cache
as long as :
1, we have a lease for the parent directory and a timestamp when the lease
was aquired.
2, if the timestamp for when the cifs inode was cached is more recent than
the timestamp for the lease.
I.e. we can server cached attributes back to userspace until the lease
has expired nad not need to rely on (unsafe) actimo.
