Re: [Jfs-discussion] hung file problem

[Dave K. <sh...@au...>]

On Wed, 2005-06-29 at 15:21 -0700, Kurt Albershardt wrote:
> Red Hat 8 (kernel 2.4.20-28.8) with jfsutils 1.1.7
> Mirrored drives using 3Ware controller

I'm not sure what level of jfs is in that kernel, or whether a patch
might help.  I can look into it more tomorrow.

> Every so often I get a hung mailbox file that ends up with many
> threads stuck on it.  In this case, 178 threads -- almost all
> belonging to the mailserver but also some ls and cp threads where I
> tried to save the mailbox.  Either of the aforementioned commands will
> hang a session and even after the session has been terminated (closing
> the SSH client.)

Does dmesg give you any clue as to a possible oops in jfs code?  You get
hanging threads when something crashes while it's holding a lock on the
object.

> sync appears to work, returns a prompt afterwards.

Odd, sync often hangs in this situation.

> Is there something in the utils that might save this file? 

It may be possible with jfs_debugfs, but you'd have to be somewhat of a
jfs expert.

> Rebooting seems to be the only way to unstick, and that deletes the
> hung .mbox file.

You could edit /etc/fstab so that fsck does not run against that
partition when you reboot.  (Change the last column in the entry to
zero.)  Then mount it read-only (mount -oro) and try to copy the file.
This may still fail, but it may be worth a try.  If you recover the
file, then you can umount it and run fsck.

> --thanks

-- 
David Kleikamp
IBM Linux Technology Center