host hangs, ?can only drop to ddb after accessing a file that is owned by a non ?privileged user

[Oliver Fromme]

Ahnjoan Amous wrote:
 > A week or so ago we had a power bump and since then one of our servers
 > now hangs on access to one of two files.  Just `ls -al` will cause the
 > machine to hang.  The files are excel spreadsheets owned by a normal
 > user and served out by samba.  The host does not panic when the files
 > are accessed but the only thing I can do is break in to ddb on the
 > serial console.
 > 
 > Once inside of ddb I'm able to see which of the two files was being
 > accessed by typing in "show lockedvnods" and using the inode to
 > identify the file via the find command.  I'm not able to remove the
 > files either as this causes the host to hang in the same manner.
 > 
 > I really don't know anything about ddb other than how to type in "show
 > lockedvnods" so far.  I can reproduce this behavior every time if
 > anyone would like me to trouble shoot this possible bug.  One thing to
 > note this is a 5.2.1-Release so if it is even a bug it might be fixed
 > already.
 > 
 > Most importantly does anyone have any thoughts on how I can remove
 > this file?  Its accessible by my users and even with a preemptive
 > e-mail they seem to take delight in clicking the little icon twice and
 > watching me run down the hall...

First and most importantly, I assume you have good backups.

Unmount the file system, use clri(8) to zero out the broken
inodes, then run fsck(8) to clean up, then mount the file
system and restore the lost files from your backup.

Finally, update your FreeBSD version, because 5.x is EoL
and not supported anymore.  In particular, you don't get
security fixes for it anymore.  If your users take delight
in causing harm to your server, they could certainly do
more serious things than just cause it to crash.

By the way, if clri(8) or fsck(8) hang, too, or if the
problem persists afterwards, chances are that the disk
hardware is broken and should be replaced.

Best regards
   Oliver

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