Possible race in the filesystem code (softupdates) ?

Martin Blapp mb at imp.ch
Sun Apr 4 13:56:49 PDT 2004


During testing I found that the following procedure is pretty dangerous
and leads sometimes to a panic():

cd /usr/ports/editors/openoffice-1.1
make patch
mv work work.old
rm -rfd work.old &
make patch &
find work.old > /dev/null 2>&1

The filesystem was mounted with softupdates.

I'm trying to reproduce it tomorrow for a useful dump. I had it happen twice but
was not able to take any notices because it happenend on a productive server.
I can exclude any hardware problems. We use current from a week ago.

Find(8) seems to trigger that bug while we are deleting this really huge
work dir with ~200000 files in it and doing a stat on it at the same

I'd call the bug pretty serious. I'll post more info after I got one
more panic.

Some other thing that scares me is that reading a filesystem with many many
little files (as the openoffice work dir) slows down all IO operations. At
BSDCon Matt Dillon talked to me about this issue and about his plan to solve it.

Matt, did you make any progress here ? It is really scaring how slow UFS is
in this area.


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