autofs: remove left-over autofs4 stubs

There's no need to retain the fs/autofs4 directory for backward
compatibility.

Adding an AUTOFS4_FS fragment to the autofs Kconfig and a module alias
for autofs4 is sufficient for almost all cases. Not keeping fs/autofs4
remnants will prevent "insmod <path>/autofs4/autofs4.ko" from working
but this shouldn't be used in automation scripts rather than
modprobe(8).

There were some comments about things to look out for with the module
rename in the fs/autofs4/Kconfig that is removed by this patch, see the
commit patch if you are interested.

One potential problem with this change is that when the
fs/autofs/Kconfig fragment for AUTOFS4_FS is removed any AUTOFS4_FS
entries will be removed from the kernel config, resulting in no autofs
file system being built if there is no AUTOFS_FS entry also.

This would have also happened if the fs/autofs4 remnants had remained
and is most likely to be a problem with automated builds.

Please check your build configurations before the removal which will
occur after the next couple of kernel releases.

Acked-by: Ian Kent <raven@themaw.net>
[ With edits and commit message from Ian Kent ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/fs/autofs/Kconfig b/fs/autofs/Kconfig
index 6a2064eb3b27..55c3930a907b 100644
--- a/fs/autofs/Kconfig
+++ b/fs/autofs/Kconfig
@@ -1,3 +1,14 @@
+config AUTOFS4_FS
+	tristate "Old Kconfig name for Kernel automounter support"
+	select AUTOFS_FS
+	help
+	   This name exists for people to just automatically pick up the
+	   new name of the autofs Kconfig option. All it does is select
+	   thenew new option name.
+
+	   It will go away in a release or two as people have
+	   transitioned to just plain AUTOFS_FS.
+
 config AUTOFS_FS
 	tristate "Kernel automounter support (supports v3, v4 and v5)"
 	default n