CRED: Wrap task credential accesses in the ReiserFS filesystem

Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: reiserfs-devel@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>

fs/reiserfs/namei.c

@@ -573,7 +573,7 @@ static int new_inode_init(struct inode *inode, struct inode *dir, int mode)
 	/* the quota init calls have to know who to charge the quota to, so
 	 ** we have to set uid and gid here
 	 */
-	inode->i_uid = current->fsuid;
+	inode->i_uid = current_fsuid();
 	inode->i_mode = mode;
 	/* Make inode invalid - just in case we are going to drop it before
 	 * the initialization happens */
@@ -584,7 +584,7 @@ static int new_inode_init(struct inode *inode, struct inode *dir, int mode)
 		if (S_ISDIR(mode))
 			inode->i_mode |= S_ISGID;
 	} else {
-		inode->i_gid = current->fsgid;
+		inode->i_gid = current_fsgid();
 	}
 	DQUOT_INIT(inode);
 	return 0;