XFS defragmentation issue

[John Lister]

On 11/09/2010 09:23, Dave Chinner wrote:
> On Sat, Sep 11, 2010 at 07:55:32AM +0100, John Lister wrote:
>>   Stan Hoeppner wrote on 9/10/2010 14:00
>>>> On 10/09/2010 15:41, John Lister wrote:
>>> Try unmounting and remounting the filesystem, and see if the various
>>> tools all report the same thing afterwards. This solved the exact same
>>> problem for me very recently, though I'm on kernel 2.6.34.1 and xfsprogs
>>> 2.9.8.
>> Cheers, that got rid of most of it, there is still a slight
>> discrepency  (50 extra fragments) which I can live with.
> xfs_db used buffered IO on the block device, which is not coherent
> with the filesystem. If you are using it on an active filesystem,
> then running "echo 1>  /proc/sys/vm/drop_caches" before you run
> xfs_db should make it read from disk at least once....
Ah, that makes more sense, I'll give it a go.

Thanks

John