Subject: kern/33112: VND_COMPRESS support broken: mount_ffs: /dev/vnd0a on /mnt: incorrect super block
To: None <,,>
From: None <>
List: netbsd-bugs
Date: 03/21/2006 00:25:07
>Number:         33112
>Category:       kern
>Synopsis:       VND_COMPRESS support broken: mount_ffs: /dev/vnd0a on /mnt: incorrect super block
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Mar 21 00:25:07 +0000 2006
>Originator:     Julian Bourne
>Release:        3.99.16 (2006-03-09 daily)
NetBSD 3.99.16 NetBSD 3.99.16 (GENERIC) #0: Thu Mar  9 05:38:48 UTC 2006 i386

The cloop2 compressed vnode support in vnd.c appears to have been broken by changes introduced since the beginning of the year.

In detail, the code cannot correctly read a superblock from the vnd device for a mounted filesystem which is known to be correct on a vanilla 3.0 system.

It doesn't matter if the compressed filesystem is created on 3.0 or latest.

petra# makefs -t ffs /tmp/etc.fs /etc
Calculated size of `/tmp/etc.fs': 3514368 bytes, 289 inodes
Extent size set to 8192
/tmp/etc.fs: 3.4MB (6864 sectors) block size 8192, fragment size 1024
        using 1 cylinder groups of 3.35MB, 429 blks, 320 inodes.
super-block backups (for fsck -b #) at:
Populating `/tmp/etc.fs'
Image `/tmp/etc.fs' complete
petra# vndcompress /tmp/etc.fs /tmp/etc.cl2
Using blocksize: 65536 (53 complete and 1 zero-padded blocks)
petra# vnconfig -z vnd0 /tmp/etc.cl2
petra# mount /dev/vnd0a /mnt
mount_ffs: /dev/vnd0a on /mnt: incorrect super block