fs: remove mandatory file locking support

We added CONFIG_MANDATORY_FILE_LOCKING in 2015, and soon after turned it
off in Fedora and RHEL8. Several other distros have followed suit.

I've heard of one problem in all that time: Someone migrated from an
older distro that supported "-o mand" to one that didn't, and the host
had a fstab entry with "mand" in it which broke on reboot. They didn't
actually _use_ mandatory locking so they just removed the mount option
and moved on.

This patch rips out mandatory locking support wholesale from the kernel,
along with the Kconfig option and the Documentation file. It also
changes the mount code to ignore the "mand" mount option instead of
erroring out, and to throw a big, ugly warning.

Signed-off-by: Jeff Layton <jlayton@kernel.org>

1 files changed, 0 insertions, 10 deletions

diff --git a/fs/Kconfig b/fs/Kconfig
index a7749c126b8e..949128bf86c9 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -101,16 +101,6 @@ config FILE_LOCKING
           for filesystems like NFS and for the flock() system
           call. Disabling this option saves about 11k.
 
-config MANDATORY_FILE_LOCKING
-	bool "Enable Mandatory file locking"
-	depends on FILE_LOCKING
-	default y
-	help
-	  This option enables files appropriately marked files on appropriely
-	  mounted filesystems to support mandatory locking.
-
-	  To the best of my knowledge this is dead code that no one cares about.
-
 source "fs/crypto/Kconfig"
 
 source "fs/verity/Kconfig"