CRED: Wrap task credential accesses in the HFS 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: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: James Morris <jmorris@namei.org>

fs/hfs/inode.c

@@ -155,8 +155,8 @@ struct inode *hfs_new_inode(struct inode *dir, struct qstr *name, int mode)
 	hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);
 	inode->i_ino = HFS_SB(sb)->next_id++;
 	inode->i_mode = mode;
-	inode->i_uid = current->fsuid;
-	inode->i_gid = current->fsgid;
+	inode->i_uid = current_fsuid();
+	inode->i_gid = current_fsgid();
 	inode->i_nlink = 1;
 	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 	HFS_I(inode)->flags = 0;

fs/hfs/super.c

@@ -210,8 +210,8 @@ static int parse_options(char *options, struct hfs_sb_info *hsb)
 	int tmp, token;
 
 	/* initialize the sb with defaults */
-	hsb->s_uid = current->uid;
-	hsb->s_gid = current->gid;
+	hsb->s_uid = current_uid();
+	hsb->s_gid = current_gid();
 	hsb->s_file_umask = 0133;
 	hsb->s_dir_umask = 0022;
 	hsb->s_type = hsb->s_creator = cpu_to_be32(0x3f3f3f3f);	/* == '????' */