Re: kern/40360: fictitious disklabels do not handle devices without an MBR

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

The following reply was made to PR kern/40360; it has been noted by GNATS.

From: Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>
To: david%l8s.co.uk@localhost
Cc: gnats-bugs%NetBSD.org@localhost, kern-bug-people%NetBSD.org@localhost, 
gnats-admin%NetBSD.org@localhost,
        netbsd-bugs%NetBSD.org@localhost, tsutsui%ceres.dti.ne.jp@localhost
Subject: Re: kern/40360: fictitious disklabels do not handle devices without
         an MBR
Date: Sun, 11 Jan 2009 08:08:40 +0900

 david%l8s.co.uk@localhost wrote:
 
 > > >Description:
 > >    When inserting a USB device that only contains a FAT filesystems,
 > >    the auto-generated disklabel incorrectly reports a 4.2BSD filesystem
 > >    at the beginning of the device.
 > 
 > The filesystem type in the disklabel is fairly irrelevant.
 > Nothing during mount looks at it - so it is really just a comment.
 > (except maybe for swap).
 
 It's okay if it's "unused" against a raw partition,
 but subr_disk_mbr.c implicitly sets 4.4BSD for partitoin 'a'
 if there is no valid disklabel.
 ---
        /*
         * Set partition 'a' to be the whole disk.
         * Cleared if we find an mbr or a netbsd label.
         */
        lp->d_partitions[0].p_size = lp->d_partitions[RAW_PART].p_size;
        lp->d_partitions[0].p_fstype = FS_BSDFFS;
 ---
 It's quite a bad assumption.
 
 ---
 Izumi Tsutsui