ext2fs crash in -current (r218056)

Doug Barton dougb at FreeBSD.org
Thu Feb 3 23:04:52 UTC 2011

On 02/02/2011 14:20, Jeremy Chadwick wrote:
> On Wed, Feb 02, 2011 at 05:04:03PM -0500, John Baldwin wrote:
>> On Wednesday, February 02, 2011 04:13:48 pm Doug Barton wrote:
>>> I haven't had a chance to test this patch yet, but John's did not work
>>> (sorry):
>>> http://dougbarton.us/ext2fs-crash-dump-2.jpg
>>> No actual dump this time either.
>>> I'm happy to test the patch below on Thursday if there is consensus that
>>> it will work.
>> Err, this is a different panic than what you reported earlier.  Your disk died
>> and spewed a bunch of EIO errors.  I can look at the locking assertion failure
>> tomorrow, but this is a differnt issue.  Even UFS needed a good bit of work to
>> handle disks dying gracefully.
> Are the byte offsets shown in the screenshot within the range of the
> drive's capacity?  They're around the 10.7GB mark, but I have no idea
> what size disk is being used.

It's a USB backup drive which I've partitioned into one FAT32 and one 
ext2fs. When the crash happened I was copying a 1.1G file from the FAT32 
partition to the ext2fs. The ext2fs partition is only 10 G total. df 
output shows 10399780 1k blocks. There is plenty of room on the ext2fs 
partition for the file, only about 1.5 G of that partition is currently 
in use.

> The reason I ask is that there have been reported issues in the past
> where the offsets shown are way outside of the range of the permitted
> byte offsets of the disk itself (and in some cases even showing a
> negative number; what is it with people not understanding the difference
> between signed and unsigned types?  Sigh), and I want to make sure this
> isn't one of those situations.  I also don't know if underlying
> filesystem corruption could cause the problem in question ("filesystem
> says you should write to block N, which is outside of the permitted
> range of the device").
> Specifically with regards to the I/O errors: I can assist with verifying
> the disk has a problem, but I forget if smartmontools will work under
> FreeBSD if the hard disk is attached via umass or not.

I didn't think it would, but I tested the theory just to be sure. :)

So I'm totally willing to accept the explanation that this second crash 
is a different bug. I probably will not be able to do it today, but I'm 
still willing to stress-test John's patch if there is agreement that 
it's the right way to go. Hopefully it will fare better if it's not a 
USB disk we're dealing with.




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