This patch removes the need for zpl_revalidate altogether.
There were 3 main reasons why we used d_revalidate:
1. periodic automounted snapshots umount deferral
2. negative dentries created before snapshot rollback
3. stale inodes referenced by dentry cache after snapshot rollback
Periodic snapshots deferral solution introduces zfs_exit_fs function,
which is called as a part of ZFS_EXIT(zfsvfs_t) macro.
Negative dentries and stale inodes are solved by flushing the dcache
for the particular dataset on zfs_resume_fs call.
This patch also removes now unused HAVE_S_D_OP configure test.
Reviewed-by: Aleksa Sarai <cyphar@cyphar.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Pavel Snajdr <snajpa@snajpa.net>
Closes#8774Closes#9549