On Fri, Jun 13, 2025 at 10:37:58AM +1000, NeilBrown wrote: > > Some sysctl tables can provide an is_seen() function which reports if > the sysctl should be visible to the current process. This is currently > used to cause d_compare to fail for invisible sysctls. > > This technique might have worked in 2.6.26 when it was implemented, but > it cannot work now. In particular if ->d_compare always fails for a > particular name, then d_alloc_parallel() will always create a new dentry > and pass it to lookup() resulting in a new inode for every lookup. I > tested this by changing sysctl_is_seen() to always return 0. When > all sysctls were still visible and repeated lookups (ls -li) reported > different inode numbers. What do you mean, "name"?
