cifs: replace /proc/fs/cifs/Experimental with a module parm
This flag currently only affects whether we allow "zero-copy" writes
with signing enabled. Typically we map pages in the pagecache directly
into the write request. If signing is enabled however and the contents
of the page change after the signature is calculated but before the
write is sent then the signature will be wrong. Servers typically
respond to this by closing down the socket.
Still, this can provide a performance benefit so the "Experimental" flag
was overloaded to allow this. That's really not a good place for this
option however since it's not clear what that flag does.
Move that flag instead to a new module parameter that better describes
its purpose. That's also better since it can be set at module insertion
time by configuring modprobe.d.
Reviewed-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 17afb0f..10e4afe 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -817,7 +817,6 @@
have the uid/password or Kerberos credential
or equivalent for current user */
GLOBAL_EXTERN unsigned int oplockEnabled;
-GLOBAL_EXTERN unsigned int experimEnabled;
GLOBAL_EXTERN unsigned int lookupCacheEnabled;
GLOBAL_EXTERN unsigned int global_secflags; /* if on, session setup sent
with more secure ntlmssp2 challenge/resp */
@@ -827,6 +826,7 @@
GLOBAL_EXTERN unsigned int cifs_min_rcv; /* min size of big ntwrk buf pool */
GLOBAL_EXTERN unsigned int cifs_min_small; /* min size of small buf pool */
GLOBAL_EXTERN unsigned int cifs_max_pending; /* MAX requests at once to server*/
+GLOBAL_EXTERN bool sign_zero_copy; /* don't copy written pages with signing */
/* reconnect after this many failed echo attempts */
GLOBAL_EXTERN unsigned short echo_retries;