File system deadlock. GBDE(4) and/or MD(4) related.

Poul-Henning Kamp phk at
Thu Jul 24 13:01:12 PDT 2003

In message <20030724185922.GZ43543 at>, Pawel Jakub Dawidek writ

>+> One way or another:  It is _not_ a GBDE problem.
>Hey, Poul! I'm not trying to show that gbde(4) is a buggy software,
>I'm not trying to destroy you work, your image or FreeBSD, really.
>I believe that this isn't bug in gbde(4), my fault, sorry.

No worries, I just want to make sure that the mail archives contain
a definitive statement that this was not a GBDE problem.

>But one thing I know, is that bug is somewhere and I just want to help
>track it down.
>This information could be useful:
>When I've mounted file system on /private (not on /mnt/private) there
>is no problem anymore. So maybe deadlock is caused by some directory
>locking or something? Because if file system in mounted on /mnt/private
>deadlock is 100% reproducable.

Using vnode backed md(4) devices is sort of incestuous, and that may
be what happens here:  For certain operations it is necessary to lock
all the way to the top of the filesystem, and this may be what results
in a deadlock for you now.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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