libceph, ceph: avoid memory leak when specifying same option several times

When parsing string option, in order to avoid memory leak we need to
carefully free it first in case of specifying same option several times.
Signed-off-by: NChengguang Xu <cgxu519@icloud.com>
Reviewed-by: NIlya Dryomov <idryomov@gmail.com>
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

fs/ceph/super.c

@@ -225,6 +225,7 @@ static int parse_fsopt_token(char *c, void *private)
 			return -ENOMEM;
 		break;
 	case Opt_mds_namespace:
+		kfree(fsopt->mds_namespace);
 		fsopt->mds_namespace = kstrndup(argstr[0].from,
 						argstr[0].to-argstr[0].from,
 						GFP_KERNEL);
@@ -232,6 +233,7 @@ static int parse_fsopt_token(char *c, void *private)
 			return -ENOMEM;
 		break;
 	case Opt_fscache_uniq:
+		kfree(fsopt->fscache_uniq);
 		fsopt->fscache_uniq = kstrndup(argstr[0].from,
 					       argstr[0].to-argstr[0].from,
 					       GFP_KERNEL);

net/ceph/ceph_common.c

@@ -418,6 +418,7 @@ ceph_parse_options(char *options, const char *dev_name,
 				opt->flags |= CEPH_OPT_FSID;
 			break;
 		case Opt_name:
+			kfree(opt->name);
 			opt->name = kstrndup(argstr[0].from,
 					      argstr[0].to-argstr[0].from,
 					      GFP_KERNEL);
@@ -427,6 +428,9 @@ ceph_parse_options(char *options, const char *dev_name,
 			}
 			break;
 		case Opt_secret:
+			ceph_crypto_key_destroy(opt->key);
+			kfree(opt->key);
+
 		        opt->key = kzalloc(sizeof(*opt->key), GFP_KERNEL);
 			if (!opt->key) {
 				err = -ENOMEM;
@@ -437,6 +441,9 @@ ceph_parse_options(char *options, const char *dev_name,
 				goto out;
 			break;
 		case Opt_key:
+			ceph_crypto_key_destroy(opt->key);
+			kfree(opt->key);
+
 		        opt->key = kzalloc(sizeof(*opt->key), GFP_KERNEL);
 			if (!opt->key) {
 				err = -ENOMEM;