s3: introduce a new share config option "durable handles" defaulting to "yes"

This is in order to be able to turn durable handles off and on on a per share
basis.

Note: This is only used in combination with:

	kernel share modes = no
	kernel oplocks = no
	posix locking = no

Which means CIFS/SMB2 only access.

Signed-off-by: Stefan Metzmacher <metze@samba.org>

lib/param/param_functions.c

@@ -156,6 +156,7 @@ FN_LOCAL_CHAR(magicchar, magic_char)
 FN_LOCAL_STRING(cups_options, szCupsOptions)
 FN_LOCAL_PARM_BOOL(change_notify, bChangeNotify)
 FN_LOCAL_PARM_BOOL(kernel_change_notify, bKernelChangeNotify)
+FN_LOCAL_BOOL(durable_handles, bDurableHandles)
 
 FN_GLOBAL_BOOL(allow_insecure_widelinks, bAllowInsecureWidelinks)
 FN_GLOBAL_BOOL(allow_trusted_domains, bAllowTrustedDomains)

lib/param/param_table.c

@@ -1763,6 +1763,15 @@ static struct parm_struct parm_table[] = {
 		.special	= NULL,
 		.enum_list	= NULL
 	},
+	{
+		.label		= "durable handles",
+		.type		= P_BOOL,
+		.p_class	= P_LOCAL,
+		.offset		= LOCAL_VAR(bDurableHandles),
+		.special	= NULL,
+		.enum_list	= NULL,
+		.flags		= FLAG_ADVANCED,
+	},
 
 	{N_("Tuning Options"), P_SEP, P_SEPARATOR},
 

source3/include/proto.h

@@ -1327,6 +1327,7 @@ bool lp_afs_share(int );
 bool lp_acl_check_permissions(int );
 bool lp_acl_group_control(int );
 bool lp_acl_map_full_control(int );
+bool lp_durable_handles(int);
 int lp_create_mask(int );
 int lp_force_create_mode(int );
 int lp_security_mask(int );

source3/param/loadparm.c

@@ -282,6 +282,7 @@ static struct loadparm_service sDefault =
 #endif
 	.ismb_encrypt = SMB_SIGNING_DEFAULT,
 	.bKernelShareModes = true,
+	.bDurableHandles = true,
 	.param_opt = NULL,
 	.dummy = ""
 };