cifs: improve checking of DFS links over STATUS_OBJECT_NAME_INVALID

Do not map STATUS_OBJECT_NAME_INVALID to -EREMOTE under non-DFS
shares, or 'nodfs' mounts or CONFIG_CIFS_DFS_UPCALL=n builds.
Otherwise, in the slow path, get a referral to figure out whether it
is an actual DFS link.

This could be simply reproduced under a non-DFS share by running the
following

  $ mount.cifs //srv/share /mnt -o ...
  $ cat /mnt/$(printf '\U110000')
  cat: '/mnt/'$'\364\220\200\200': Object is remote

Fixes: c877ce47e137 ("cifs: reduce roundtrips on create/qinfo requests")
CC: [email protected] # 6.2
Signed-off-by: Paulo Alcantara (SUSE) <[email protected]>
Reviewed-by: Ronnie Sahlberg <[email protected]>
Signed-off-by: Steve French <[email protected]>

0 files changed, 0 insertions, 0 deletions