Re: cvs commit: src/sys/vfs/msdosfs msdosfs_denode.c

[Nicolas Thery <nthery@xxxxxxxxx>]

2009/2/18 Simon 'corecode' Schubert <corecode@fs.ei.tum.de>:
> Nicolas Thery wrote:
>>
>> nth         2008/06/08 00:56:06 PDT
>>
>> DragonFly src repository
>>
>>  Modified files:
>>    sys/vfs/msdosfs      msdosfs_denode.c  Log:
>>  Assert that move in directory entry hash table can't fail.
>
> I just experienced a panic with this.  How would that have been caused?

Interesting.  What error code is reported in the assertion message?

I added this assertion while debugging a msdos bug/crash reported by
somebody (maybe
you but I can't tell for sure) back in May or June.  Unfortunately I
can't find the details in my
aging memory nor in the list archives.  Shame on me for not being more
explicit in my
commit log.

Anyway, I couldn't root cause the bug but from the crash dump I
strongly suspected it was
caused by a failure to reinsert a denode in the hash table so I added
the assertion to
confirm/infirm my hypothesis.

As to what could cause such a failure I need to dive again in this
code, but it looks like the
denode is already in the hash table (though removed a few lines above)
so there might be a
race.

If you have a call stack or a dump, I'll try to give it a look this week.