Merge tag '4.20-rc1-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes and updates from Steve French:
 "Three small fixes (one Kerberos related, one for stable, and another
  fixes an oops in xfstest 377), two helpful debugging improvements,
  three patches for cifs directio and some minor cleanup"

* tag '4.20-rc1-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix signed/unsigned mismatch on aio_read patch
  cifs: don't dereference smb_file_target before null check
  CIFS: Add direct I/O functions to file_operations
  CIFS: Add support for direct I/O write
  CIFS: Add support for direct I/O read
  smb3: missing defines and structs for reparse point handling
  smb3: allow more detailed protocol info on open files for debugging
  smb3: on kerberos mount if server doesn't specify auth type use krb5
  smb3: add trace point for tree connection
  cifs: fix spelling mistake, EACCESS -> EACCES
  cifs: fix return value for cifs_listxattr