Re: ext3_free_blocks

["Stephen C. Tweedie" <sct redhat com>]

Hi,

On Wed, Sep 19, 2001 at 01:30:54PM -0700, RW Hawkins wrote:
> I am getting the following error under moderate load on one of our 
> fileserver:
> 
> Sep 19 12:44:03 ara kernel: EXT3-fs warning (device sd(8,49)): 
> ext3_free_blocks: bit already cleared for block 35949297
> Sep 19 12:44:03 ara last message repeated 9 times
> 
> When this occurs NFSD goes out of control and the load pegs and the 
> machine needs a reboot. This is kernel 2.2.19, ext3-0.0.7a with quotas 
> enabled. Does anyone have an idea what is going on here?

Well, the immediate problem isn't ext3-specific --- the error message
is in ext2 too.  The filesystem is trying to delete a block which is
already free on disk.  That can happen for a huge variety of reasons:
bad memory, disk corruption, or any sort of kernel bugs including
filesystem faults, virtual memory faults or driver bugs.

The first step is always to unmount the filesystem and force a fsck on
it (fsck -f if necessary).  Beyond that, if it recurs, we have a long
and slow process to try to eliminate possible sources of the problem.

Cheers,
 Stephen