Re: Corruption of UFS filesystems after using md(4)

On Tue, Nov 02, 2010 at 07:33:50PM +0000, Bruce Cran wrote:
> On Tuesday 02 November 2010 19:12:14 Bruce Cran wrote:
> > I've noticed in recent months that I appear to be getting silent corruption
> > of my UFS filesystems - and I think it may be linked to using md(4) or
> > creating sparse files.
> 
> I've confirmed this is a UFS bug related to sparse files: "truncate -s20G f1 
> && rm f1" is enough to trigger the error and start generating .viminfo files 
> that appear to be 20GB. When running fsck I get an "Invalid block count" error 
> if I just reboot without removing the .viminfo file; if I do remove it, I get 
> a "Partially allocated inode" error.
> 

I'm able to verify this by:

"m.sh" 49L, 1917C written
$ ./m.sh
Local config: x4
+ mdconfig -a -t swap -s 1g -u 5
+ bsdlabel -w md5 auto
+ newfs -U md5a
+ mount /dev/md5a /mnt
+ truncate -s20G /mnt/f1
+ rm /mnt/f1
+ umount /mnt
+ fsck -t ufs -y /dev/md5a
** /dev/md5a
** Last Mounted on /mnt
** Phase 1 - Check Blocks and Sizes
PARTIALLY ALLOCATED INODE I=4
UNEXPECTED SOFT UPDATE INCONSISTENCY

CLEAR? yes

** Phase 2 - Check Pathnames
** Phase 3 - Check Connectivity
** Phase 4 - Check Reference Counts
** Phase 5 - Check Cyl groups
FREE BLK COUNT(S) WRONG IN SUPERBLK
SALVAGE? yes

SUMMARY INFORMATION BAD
SALVAGE? yes

BLK(S) MISSING IN BIT MAPS
SALVAGE? yes

2 files, 2 used, 506481 free (25 frags, 63307 blocks, 0.0%
fragmentation)

***** FILE SYSTEM IS CLEAN *****

***** FILE SYSTEM WAS MODIFIED *****
+ mdconfig -d -u 5
$ 

- Peter