CRED: Wrap task credential accesses in the HPFS 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: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c
index 29ad461..0d049b8 100644
--- a/fs/hpfs/super.c
+++ b/fs/hpfs/super.c
@@ -475,8 +475,8 @@
 
 	init_MUTEX(&sbi->hpfs_creation_de);
 
-	uid = current->uid;
-	gid = current->gid;
+	uid = current_uid();
+	gid = current_gid();
 	umask = current->fs->umask;
 	lowercase = 0;
 	conv = CONV_BINARY;