NFS: make sure lock/nolock overriding local_lock mount option

Currently, mount option lock/nolock and local_lock option
may override NFS_MOUNT_LOCAL_FLOCK NFS_MOUNT_LOCAL_FCNTL flags
when passing in different order:

mount -o vers=3,local_lock=all,lock:
	local_lock=none

mount -o vers=3,lock,local_lock=all:
	local_lock=all

This patch will let lock/nolock override local_lock option
as nfs(5) suggested.
Signed-off-by: Chen Hanxiao <chenhx.fnst@fujitsu.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/fs_context.c

@@ -600,9 +600,11 @@ static int nfs_fs_context_parse_param(struct fs_context *fc,
 		break;
 	case Opt_lock:
 		if (result.negated) {
+			ctx->lock_status = NFS_LOCK_NOLOCK;
 			ctx->flags |= NFS_MOUNT_NONLM;
 			ctx->flags |= (NFS_MOUNT_LOCAL_FLOCK | NFS_MOUNT_LOCAL_FCNTL);
 		} else {
+			ctx->lock_status = NFS_LOCK_LOCK;
 			ctx->flags &= ~NFS_MOUNT_NONLM;
 			ctx->flags &= ~(NFS_MOUNT_LOCAL_FLOCK | NFS_MOUNT_LOCAL_FCNTL);
 		}

fs/nfs/internal.h

@@ -112,6 +112,7 @@ struct nfs_fs_context {
 	unsigned short		protofamily;
 	unsigned short		mountfamily;
 	bool			has_sec_mnt_opts;
+	int			lock_status;
 
 	struct {
 		union {
@@ -153,6 +154,12 @@ struct nfs_fs_context {
 	} clone_data;
 };
 
+enum nfs_lock_status {
+	NFS_LOCK_NOT_SET	= 0,
+	NFS_LOCK_LOCK		= 1,
+	NFS_LOCK_NOLOCK		= 2,
+};
+
 #define nfs_errorf(fc, fmt, ...) ((fc)->log.log ?		\
 	errorf(fc, fmt, ## __VA_ARGS__) :			\
 	({ dprintk(fmt "\n", ## __VA_ARGS__); }))

fs/nfs/super.c

@@ -901,6 +901,16 @@ static struct nfs_server *nfs_try_mount_request(struct fs_context *fc)
 	rpc_authflavor_t authlist[NFS_MAX_SECFLAVORS];
 	unsigned int authlist_len = ARRAY_SIZE(authlist);
 
+	/* make sure 'nolock'/'lock' override the 'local_lock' mount option */
+	if (ctx->lock_status) {
+		if (ctx->lock_status == NFS_LOCK_NOLOCK) {
+			ctx->flags |= NFS_MOUNT_NONLM;
+			ctx->flags |= (NFS_MOUNT_LOCAL_FLOCK | NFS_MOUNT_LOCAL_FCNTL);
+		} else {
+			ctx->flags &= ~NFS_MOUNT_NONLM;
+			ctx->flags &= ~(NFS_MOUNT_LOCAL_FLOCK | NFS_MOUNT_LOCAL_FCNTL);
+		}
+	}
 	status = nfs_request_mount(fc, ctx->mntfh, authlist, &authlist_len);
 	if (status)
 		return ERR_PTR(status);