bug#32520: 26.1; problem with CIFS mounts

[emacs@martins.cc]

I automount windows shares under a common mountpoint, say /cifs.

When I cd to or references something like:
  /cifs/<host>/<share>/path/to/file_or_dir
the windows share is mounted on
  /cifs/<host>/<share>
and the process can get to .../path/to/file_or_dir.

When I visit one of those directories with emacs 26 (maybe
also files on that share), I get a bunch of syslog warnings
from the CIFS subsystem.

Sometimes they just say:

  [608270.512407] CIFS VFS: BAD_NETWORK_NAME: \\host\.dir-locals-2.el
  [608270.512744] CIFS VFS: cifs_mount failed w/return code = -2
  [608270.517939] CIFS VFS: BAD_NETWORK_NAME: \\host\.dir-locals.el
  [608270.518326] CIFS VFS: cifs_mount failed w/return code = -2

Other times it goes full looking for more stuff, like:

  [600979.586694] CIFS VFS: BAD_NETWORK_NAME: \\host\.dir-locals-2.el
  [600979.587097] CIFS VFS: cifs_mount failed w/return code = -2
  [600979.597115] CIFS VFS: BAD_NETWORK_NAME: \\host\.dir-locals.el
  [600979.597598] CIFS VFS: cifs_mount failed w/return code = -2
  [600979.611685] CIFS VFS: BAD_NETWORK_NAME: \\host\.svn
  [600979.612153] CIFS VFS: cifs_mount failed w/return code = -2
  [600979.638103] CIFS VFS: BAD_NETWORK_NAME: \\host\.bzr
  [600979.638532] CIFS VFS: cifs_mount failed w/return code = -2
  [600979.648746] CIFS VFS: BAD_NETWORK_NAME: \\host\.git
  [600979.649193] CIFS VFS: cifs_mount failed w/return code = -2
  [600979.664967] CIFS VFS: BAD_NETWORK_NAME: \\host\.hg
  [600979.665430] CIFS VFS: cifs_mount failed w/return code = -2
  [600979.664967] CIFS VFS: BAD_NETWORK_NAME: \\host\_MTN
  [600979.665430] CIFS VFS: cifs_mount failed w/return code = -2

I don't remember this happening for emacs 25.x.

It is clogging my syslog with bogus messages, as I do visit
lots of files and directories on remote windows share every
day.

-- Henrique

------------------------------------------------------------

In GNU Emacs 26.1 (build 1, x86_64-redhat-linux-gnu, GTK+ Version 3.22.30)
 of 2018-06-26 built on buildhw-10.phx2.fedoraproject.org
Windowing system distributor 'Fedora Project', version 11.0.11906000
System Description:	Fedora release 28 (Twenty Eight)

Configured using:
 'configure --build=x86_64-redhat-linux-gnu
 --host=x86_64-redhat-linux-gnu --program-prefix=
 --disable-dependency-tracking --prefix=/usr
 --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin
 --sysconfdir=/etc --datadir=/usr/share
 --includedir=/usr/include --libdir=/usr/lib64
 --libexecdir=/usr/libexec --localstatedir=/var
 --sharedstatedir=/var/lib --mandir=/usr/share/man
 --infodir=/usr/share/info --with-dbus --with-gif
 --with-jpeg --with-png --with-rsvg --with-tiff --with-xft
 --with-xpm --with-x-toolkit=gtk3 --with-gpm=no
 --with-xwidgets --with-modules
 build_alias=x86_64-redhat-linux-gnu
 host_alias=x86_64-redhat-linux-gnu 'CFLAGS=-DMAIL_USE_LOCKF
 -O2 -g -pipe -Wall -Werror=format-security
 -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS
 -fexceptions -fstack-protector-strong -grecord-gcc-switches
 -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64
 -mtune=generic -fasynchronous-unwind-tables
 -fstack-clash-protection -fcf-protection'
 LDFLAGS=-Wl,-z,relro
 PKG_CONFIG_PATH=:/usr/lib64/pkgconfig:/usr/share/pkgconfig'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND DBUS GSETTINGS
NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT
LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 MODULES THREADS
XWIDGETS LCMS2

Important settings:
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: @im=none
  locale-coding-system: utf-8-unix

Major mode: Fundamental

Minor modes in effect:
  shell-dirtrack-mode: t
  display-time-mode: t
  erc-services-mode: t
  erc-networks-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
~/emacs/gnu/filladapt hides /usr/share/emacs/site-lisp/goodies/filladapt
~/emacs/gnu/matlab hides /usr/share/emacs/site-lisp/goodies/matlab
~/emacs/gnu/misc hides /usr/share/emacs/26.1/lisp/misc
~/emacs/gnu/mh-comp hides /usr/share/emacs/26.1/lisp/mh-e/mh-comp
~/emacs/gnu/mh-identity hides /usr/share/emacs/26.1/lisp/mh-e/mh-identity
~/emacs/gnu/mh-thread hides /usr/share/emacs/26.1/lisp/mh-e/mh-thread
/usr/share/emacs/site-lisp/gnus-bonus/spam-stat hides /usr/share/emacs/26.1/lisp/gnus/spam-stat
/usr/share/emacs/site-lisp/gnus-bonus/nnir hides /usr/share/emacs/26.1/lisp/gnus/nnir
/usr/share/emacs/site-lisp/gnus-bonus/nnnil hides /usr/share/emacs/26.1/lisp/gnus/nnnil

Features:
(shadow emacsbug rect etags xref project epa-file pcmpl-unix
conf-mode dired-aux vc-dispatcher vc-svn mhtml-mode css-mode
eww mm-url url-queue js advice cc-mode cc-fonts cc-guess
cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars
cc-defs sgml-mode flyspell cal-move cal-menu calendar
cal-loaddefs mh-alias multi-prompt crm misearch
multi-isearch mh-search dabbrev y-mh-alias sh-script smie
executable calc-misc calc-alg calc-ext calc-menu calc
calc-loaddefs calc-macs shr-color color shr svg dom
browse-url canlock man ispell mh-identity quail mh-letter
mh-comp sendmail shell pcomplete comint ring ibuf-ext
ibuffer ibuffer-loaddefs mh-funcs sort ansi-color gnus-async
gnus-bcklg gnus-kill gnus-ml disp-table nndraft nnmh
cl-extra help-mode network-stream nsm starttls gnus-agent
gnus-srvr gnus-score score-mode nnvirtual gnus-msg nntp
gnus-cache flow-fill term/xterm xterm qp mm-archive
mh-thread mail-extr mh-mime mh-gnus mh-show goto-addr
gnus-cite gnus-art mm-uu mml2015 mm-view mml-smime smime dig
gnus-sum gnus-group gnus-undo gnus-start gnus-cloud nnimap
nnmail mail-source tls gnutls utf7 netrc nnoo parse-time
gnus-spec gnus-int gnus-win gnus-range gnus nnheader mh-seq
mh-inc hl-line mh-tool-bar mh-xface mh-utils mh-folder
which-func imenu mh-scan mh-e mh-compat mh-buffers
mh-loaddefs elec-pair server time erc-services erc-networks
erc-goodies erc erc-backend erc-compat thingatpt pp md4rd
tree-mode tree-widget wid-edit s json request url url-proxy
url-privacy url-expand url-methods url-history url-cookie
url-domsuf url-util mailcap dash hierarchy subr-x map
filladapt message rmc puny dired dired-loaddefs format-spec
rfc822 mml mml-sec epa derived epg gnus-util rmail
rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse
rfc2231 rfc2047 rfc2045 mm-util ietf-drums mail-prsvr
mailabbrev mail-utils gmm-utils mailheader finder-inf
package easymenu epg-config url-handlers url-parse
auth-source cl-seq eieio eieio-core eieio-loaddefs
password-cache url-vars seq byte-opt bytecomp byte-compile
cconv preview-latex emacs-goodies-loaddefs easy-mmode
clang-format cl-macs gv xml cl-loaddefs cl-lib auto-loads
tex-site time-date mule-util tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel term/x-win x-win
term/common-win x-dnd tool-bar dnd fontset image regexp-opt
fringe tabulated-list replace newcomment text-mode
elisp-mode lisp-mode prog-mode register page menu-bar
rfn-eshadow isearch timer select scroll-bar mouse jit-lock
font-lock syntax facemenu font-core term/tty-colors frame
cl-generic cham georgian utf-8-lang misc-lang vietnamese
tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian
cyrillic chinese composite charscript charprop case-table
epa-hook jka-cmpr-hook help simple abbrev obarray minibuffer
cl-preloaded nadvice loaddefs button faces cus-face macroexp
files text-properties overlay sha1 md5 base64 format env
code-pages mule custom widget hashtable-print-readable
backquote dbusbind inotify lcms2 dynamic-setting
system-font-setting font-render-setting xwidget-internal
move-toolbar gtk x-toolkit x multi-tty make-network-process
emacs)

Memory information:
((conses 16 394990 64423)
 (symbols 48 46151 1)
 (miscs 40 855 1674)
 (strings 32 110554 9416)
 (string-bytes 1 3506280)
 (vectors 16 54656)
 (vector-slots 8 1673894 141522)
 (floats 8 451 627)
 (intervals 56 10270 2699)
 (buffers 992 70))