NFSv4: Introduce new label structure

In order to mimic the way that NFSv4 ACLs are implemented we have created a
structure to be used to pass label data up and down the call chain. This patch
adds the new structure and new members to the required NFSv4 call structures.

Signed-off-by: Matthew N. Dodd <Matthew.Dodd@sparta.com>
Signed-off-by: Miguel Rodel Felipe <Rodel_FM@dsi.a-star.edu.sg>
Signed-off-by: Phua Eu Gene <PHUA_Eu_Gene@dsi.a-star.edu.sg>
Signed-off-by: Khin Mi Mi Aung <Mi_Mi_AUNG@dsi.a-star.edu.sg>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/inode.c

@@ -257,6 +257,34 @@ nfs_init_locked(struct inode *inode, void *opaque)
 	return 0;
 }
 
+#ifdef CONFIG_NFS_V4_SECURITY_LABEL
+struct nfs4_label *nfs4_label_alloc(struct nfs_server *server, gfp_t flags)
+{
+	struct nfs4_label *label = NULL;
+	int minor_version = server->nfs_client->cl_minorversion;
+
+	if (minor_version < 2)
+		return label;
+
+	if (!(server->caps & NFS_CAP_SECURITY_LABEL))
+		return label;
+
+	label = kzalloc(sizeof(struct nfs4_label), flags);
+	if (label == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	label->label = kzalloc(NFS4_MAXLABELLEN, flags);
+	if (label->label == NULL) {
+		kfree(label);
+		return ERR_PTR(-ENOMEM);
+	}
+	label->len = NFS4_MAXLABELLEN;
+
+	return label;
+}
+EXPORT_SYMBOL_GPL(nfs4_label_alloc);
+#endif
+
 /*
  * This is our front-end to iget that looks up inodes by file handle
  * instead of inode number.

include/linux/nfs4.h

@@ -32,6 +32,15 @@ struct nfs4_acl {
 	struct nfs4_ace	aces[0];
 };
 
+#define NFS4_MAXLABELLEN	2048
+
+struct nfs4_label {
+	uint32_t	lfs;
+	uint32_t	pi;
+	u32		len;
+	char	*label;
+};
+
 typedef struct { char data[NFS4_VERIFIER_SIZE]; } nfs4_verifier;
 
 struct nfs_stateid4 {

include/linux/nfs_fs.h

@@ -496,6 +496,24 @@ extern const struct inode_operations nfs_referral_inode_operations;
 extern int nfs_mountpoint_expiry_timeout;
 extern void nfs_release_automount_timer(void);
 
+/*
+ * linux/fs/nfs/nfs4proc.c
+ */
+#ifdef CONFIG_NFS_V4_SECURITY_LABEL
+extern struct nfs4_label *nfs4_label_alloc(struct nfs_server *server, gfp_t flags);
+static inline void nfs4_label_free(struct nfs4_label *label)
+{
+	if (label) {
+		kfree(label->label);
+		kfree(label);
+	}
+	return;
+}
+#else
+static inline struct nfs4_label *nfs4_label_alloc(struct nfs_server *server, gfp_t flags) { return NULL; }
+static inline void nfs4_label_free(void *label) {}
+#endif
+
 /*
  * linux/fs/nfs/unlink.c
  */

include/linux/nfs_xdr.h

@@ -349,6 +349,7 @@ struct nfs_openargs {
 	const u32 *		open_bitmap;
 	__u32			claim;
 	enum createmode4	createmode;
+	const struct nfs4_label *label;
 };
 
 struct nfs_openres {
@@ -358,6 +359,7 @@ struct nfs_openres {
 	struct nfs4_change_info	cinfo;
 	__u32                   rflags;
 	struct nfs_fattr *      f_attr;
+	struct nfs4_label	*f_label;
 	struct nfs_seqid *	seqid;
 	const struct nfs_server *server;
 	fmode_t			delegation_type;
@@ -600,6 +602,7 @@ struct nfs_entry {
 	int			eof;
 	struct nfs_fh *		fh;
 	struct nfs_fattr *	fattr;
+	struct nfs4_label  *label;
 	unsigned char		d_type;
 	struct nfs_server *	server;
 };
@@ -632,6 +635,7 @@ struct nfs_setattrargs {
 	struct iattr *                  iap;
 	const struct nfs_server *	server; /* Needed for name mapping */
 	const u32 *			bitmask;
+	const struct nfs4_label		*label;
 };
 
 struct nfs_setaclargs {
@@ -667,6 +671,7 @@ struct nfs_getaclres {
 struct nfs_setattrres {
 	struct nfs4_sequence_res	seq_res;
 	struct nfs_fattr *              fattr;
+	struct nfs4_label		*label;
 	const struct nfs_server *	server;
 };
 
@@ -864,13 +869,15 @@ struct nfs4_create_arg {
 	const struct iattr *		attrs;
 	const struct nfs_fh *		dir_fh;
 	const u32 *			bitmask;
+	const struct nfs4_label		*label;
 };
 
 struct nfs4_create_res {
 	struct nfs4_sequence_res	seq_res;
 	const struct nfs_server *	server;
 	struct nfs_fh *			fh;
 	struct nfs_fattr *		fattr;
+	struct nfs4_label		*label;
 	struct nfs4_change_info		dir_cinfo;
 };
 
@@ -895,6 +902,7 @@ struct nfs4_getattr_res {
 	struct nfs4_sequence_res	seq_res;
 	const struct nfs_server *	server;
 	struct nfs_fattr *		fattr;
+	struct nfs4_label		*label;
 };
 
 struct nfs4_link_arg {
@@ -909,6 +917,7 @@ struct nfs4_link_res {
 	struct nfs4_sequence_res	seq_res;
 	const struct nfs_server *	server;
 	struct nfs_fattr *		fattr;
+	struct nfs4_label		*label;
 	struct nfs4_change_info		cinfo;
 	struct nfs_fattr *		dir_attr;
 };
@@ -926,6 +935,7 @@ struct nfs4_lookup_res {
 	const struct nfs_server *	server;
 	struct nfs_fattr *		fattr;
 	struct nfs_fh *			fh;
+	struct nfs4_label		*label;
 };
 
 struct nfs4_lookup_root_arg {