Re: [PATCH] NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check

On Fri, 12 Jun 2026 15:14:10 -0400, Mike Snitzer wrote:
> The header for commit e75b23f9e323 ("nfsd: check d_can_lookup in
> fh_verify of directories") details the assumption that justified
> adding the WARN_ON_ONCE to nfsd_mode_check(), that assumption is
> invalid (in the case of NFS reexport).
> 
> When NFSD exports an NFS filesystem it is very possible for
> nfsd_mode_check() to encounter a @dentry that doesn't have
> i_op->lookup (see nfs_fhget()'s NFS_ATTR_FATTR_MOUNTPOINT and
> NFS_ATTR_FATTR_V4_REFERRAL handling, and d_flags_for_inode()).
> 
> [...]

Applied to nfsd-testing, thanks!

[1/1] NFSD: remove flawed WARN_ON_ONCE from nfsd_mode_check
      commit: 4b4af25d320d077102026bf72fa2b73614f2605c

--
Chuck Lever