FS errors during unmount after dump'ing

Hi!

Once in a week I backup my PC using amanda (which uses dump(8)). Subsequently 
unmounting a filesystem (or during shutdown) I get errors like these:

handle_workitem_freeblocks: inode 3579904 block count 384
handle_workitem_freeblocks: inode 3579962 block count 384
/spare: unmount pending error: blocks 768 files 0
softdep_waitidle: Failed to flush worklist for 0xc5be2288
softdep_waitidle: Failed to flush worklist for 0xc5be2288
softdep_waitidle: Failed to flush worklist for 0xc5be2288
softdep_waitidle: Failed to flush worklist for 0xc5be2288
softdep_waitidle: Failed to flush worklist for 0xc5be2288
softdep_waitidle: Failed to flush worklist for 0xc5be2510
softdep_waitidle: Failed to flush worklist for 0xc5be2510
/data: unmount pending error: blocks 84 files 0

Note, I get these messages *only* after dumping filesystems!

Is there anything wrong with my filesystems?

Any clues?

Ciao,
Christian.