On Mon, Feb 24, 2025 at 01:06:24AM +0000, Al Viro wrote: > PS: turns out that set_default_d_op() is slightly more interesting > than I expected - fuse has separate dentry_operations for its > root dentry. I don't see the point, TBH - the only difference is > that root one lacks > * ->d_delete() (never even called for root dentry; it's > only called if d_unhashed() is false) > * ->d_revalidate() (never called for root) > * ->d_automount() (not even looked at unless you have > S_AUTOMOUNT set on the inode). > What's wrong with using fuse_dentry_operations for root dentry? > Am I missing something subtle here? Miklos? Speaking of fun questions - does pidfs_dentry_operations need ->d_delete()? I mean, it's not even called for unhashed dentries and AFAICS there's no way for those to be hashed... The same goes for all filesystems created by init_pseudo(). Is there any reason to have that in pidfs_dentry_operations and ns_dentry_operations? I think nsfs is my sloppiness back then - original commit message explicitly says that neither dentries nor inodes in that thing are ever hashed, so ->d_delete() had been clearly pointless from the very beginning. Christian, pidfs looks like it just had copied that from nsfs. Is there something subtle about pidfs that makes ->d_delete() needed there?
