add new module parameter 'enable_oplocks'

Thus spake Jeff Layton:

"Making that a module parm would allow you to set that parameter at boot
time without needing to add special startup scripts. IMO, all of the
procfile "switches" under /proc/fs/cifs should be module parms
instead."

This patch doesn't alter the default behavior (Oplocks are enabled by
default).

To disable oplocks when loading the module, use

   modprobe cifs enable_oplocks=0

(any of '0' or 'n' or 'N' conventions can be used).

To disable oplocks at runtime using the new interface, use

   echo 0 > /sys/module/cifs/parameters/enable_oplocks

The older /proc/fs/cifs/OplockEnabled interface will be deprecated
after two releases. A subsequent patch will add an warning message
about this deprecation.

Changes since v2:
   - make enable_oplocks a 'bool'

Changes since v1:
   - eliminate the use of extra variable by renaming the old one to
     enable_oplocks and make it an 'int' type.

Reported-by: Alexander Swen <alex@swen.nu>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 95dad9d14cf1..d734dee9d495 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -964,7 +964,8 @@ GLOBAL_EXTERN unsigned int multiuser_mount; /* if enabled allows new sessions
                                 to be established on existing mount if we
                                 have the uid/password or Kerberos credential
                                 or equivalent for current user */
-GLOBAL_EXTERN unsigned int oplockEnabled;
+/* enable or disable oplocks */
+GLOBAL_EXTERN bool enable_oplocks;
 GLOBAL_EXTERN unsigned int lookupCacheEnabled;
 GLOBAL_EXTERN unsigned int global_secflags;     /* if on, session setup sent
                                 with more secure ntlmssp2 challenge/resp */