freebsd stable - Oct 2003 - UFS file system problem in either stable or current

There seems to be an inconsistency between release 4.9-RC and 5.1 ufs
support.  If I fsck the same ufs (type 1 of course) file system on
both releases, each claims that the other has left incorrect
summary data in the superblock.  Presumably only one can be correct.
I just don't know which to blame.

I couldn't find a FreeBSD problem report about bad summary data.
I will submit one, but since FreeBSD 4.9 is about to be released,
someone might like to check this out.

I happen to have multiple FreeBSD operating systems installed on
the same computer.  This might also be an issue if you move an
external disk between computers.  I don't know if the problem shows
up on all file systems.  It seems to happen on all the half dozen
or so of the file systems that my 4.9-RCx and 5.1 systems share.

Dan Strick
strick@covad.net

Dan Strick wrote:
> There seems to be an inconsistency between release 4.9-RC and 5.1 ufs
> support.  If I fsck the same ufs (type 1 of course) file system on
> both releases, each claims that the other has left incorrect
> summary data in the superblock.  Presumably only one can be correct.
> I just don't know which to blame.
> 
> I couldn't find a FreeBSD problem report about bad summary data.
> I will submit one, but since FreeBSD 4.9 is about to be released,
> someone might like to check this out.
> 
> I happen to have multiple FreeBSD operating systems installed on
> the same computer.  This might also be an issue if you move an
> external disk between computers.  I don't know if the problem shows
> up on all file systems.  It seems to happen on all the half dozen
> or so of the file systems that my 4.9-RCx and 5.1 systems share.
> 
There is no problem AFAIK, you just have to fsck with the matching 
executable.  A lot has changed with FreeBSD 5, spend some time with the 
-current archive and you will learn more.  I'm sure you noticed how your 
findings are consistently inconsistent.

Pete...

Wed, Oct 22, 2003 at 03:14:33, strick (Dan Strick) wrote about "UFS file
system problem in either stable or current":

DS> There seems to be an inconsistency between release 4.9-RC and 5.1 ufs
DS> support.  If I fsck the same ufs (type 1 of course) file system on
DS> both releases, each claims that the other has left incorrect
DS> summary data in the superblock.  Presumably only one can be correct.
DS> I just don't know which to blame.

Does this require explicit fsck?
I have dual-booting between 4.9-release (and all previous 4.* releases earlier)
and 5.1 (of 20030526) with shared disks and boot checking required in fstab;
sometimes one of them crash and forced checking is made; neither 4.* nor 5.1
claims superblock is bad.


-netch-

On Sun, 2 Nov 2003, Valentin Nechayev wrote:
> Wed, Oct 22, 2003 at 03:14:33, strick (Dan Strick) wrote about "UFS
file
> system problem in either stable or current":
> DS> There seems to be an inconsistency between release 4.9-RC and 5.1
ufs
> DS> support.  If I fsck the same ufs (type 1 of course) file system on
> DS> both releases, each claims that the other has left incorrect
> DS> summary data in the superblock.  Presumably only one can be correct.
> DS> I just don't know which to blame.
>
> Does this require explicit fsck?
> I have dual-booting between 4.9-release (and all previous 4.* releases
earlier)
> and 5.1 (of 20030526) with shared disks and boot checking required in
fstab;
> sometimes one of them crash and forced checking is made; neither 4.* nor
5.1
> claims superblock is bad.
You wouldn't notice after a crash.  The incompatibility turns out to be
the location and perhaps details of the "summary information" (e.g.
number
of free blocks) in the superblock.  This does not affect the integrity of
the file system.  It does affect the output of the "df" command.

The first time you run fsck on a file system after modifying it
when running the other operating system, fsck will probably find
inconsistent super block summary data.  "fsck -p" will correct it
without asking (and might not even say much about it).

I recently read something in one of the FreeBSD newsgroups that
suggests that this incompatibility between 4.x and 5.x has in some
sense been corrected in -current.  I don't know any details.

See also:
	<http://www.freebsd.org/cgi/getmsg.cgi?fetch=446102+449665+/usr/local/www/db/text/2003/freebsd-current/20031102.freebsd-current>

Dan Strick
strick@covad.net