This cherry-picks upstream ed566bf1cd
- Add a zfs_exit() call in an error path, otherwise a lock is
leaked.
- Remove the fid_gen > 1 check. That appears to be Linux-specific:
zfsctl_snapdir_fid() sets fid_gen to 0 or 1 depending on whether
the snapshot directory is mounted. On FreeBSD it fails, making
snapshot dirs inaccessible via NFS.
PR: 266236
MFC after: 3 days