Merge tag 'afs-fixes-20231124' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull AFS fixes from David Howells:

 - Fix the afs_server_list struct to be cleaned up with RCU

 - Fix afs to translate a no-data result from a DNS lookup into ENOENT,
   not EDESTADDRREQ for consistency with OpenAFS

 - Fix afs to translate a negative DNS lookup result into ENOENT rather
   than EDESTADDRREQ

 - Fix file locking on R/O volumes to operate in local mode as the
   server doesn't handle exclusive locks on such files

 - Set SB_RDONLY on superblocks for RO and Backup volumes so that the
   VFS can see that they're read only

* tag 'afs-fixes-20231124' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Mark a superblock for an R/O or Backup volume as SB_RDONLY
  afs: Fix file locking on R/O volumes to operate in local mode
  afs: Return ENOENT if no cell DNS record can be found
  afs: Make error on cell lookup failure consistent with OpenAFS
  afs: Fix afs_server_list to be cleaned up with RCU