fs/9p: Add access = client option to opt in acl evaluation.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index 38dc0e0..2f77cd3 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -193,7 +193,17 @@
 				v9ses->flags |= V9FS_ACCESS_USER;
 			else if (strcmp(s, "any") == 0)
 				v9ses->flags |= V9FS_ACCESS_ANY;
-			else {
+			else if (strcmp(s, "client") == 0) {
+#ifdef CONFIG_9P_FS_POSIX_ACL
+				v9ses->flags |= V9FS_ACCESS_CLIENT;
+#else
+				P9_DPRINTK(P9_DEBUG_ERROR,
+					"access=client option not supported\n");
+				kfree(s);
+				ret = -EINVAL;
+				goto free_and_return;
+#endif
+			} else {
 				v9ses->flags |= V9FS_ACCESS_SINGLE;
 				v9ses->uid = simple_strtoul(s, &e, 10);
 				if (*e != '\0')
@@ -278,6 +288,16 @@
 
 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
 
+	if (!v9fs_proto_dotl(v9ses) &&
+	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
+		/*
+		 * We support ACCESS_CLIENT only for dotl.
+		 * Fall back to ACCESS_USER
+		 */
+		v9ses->flags &= ~V9FS_ACCESS_MASK;
+		v9ses->flags |= V9FS_ACCESS_USER;
+	}
+	/*FIXME !! */
 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {