[fpc-pascal] XML files and the ext4 bug

[Michael Van Canneyt]

On Wed, 11 Mar 2009, Gustavo Enrique Jimenez wrote:

> Hi
> 
> Seems like the ext4 file system has a bug or some issue with files
> updated often :
> 
> https://bugs.edge.launchpad.net/ubuntu/+source/linux/+bug/317781
> 
> I use XML files heavily. It is great, XML units save me a lot of work
> ! My programs update de xml files quite often.
> 
> I am concerned about this particular ext4 bug. Could you say if
> freepascal's XML units are affected by this bug ? ext4 developers
> recomend this :

Well, there is no 'bug', there is a misunderstanding of how things work.
That said, XML algorithms use method 1.

You can do method 3 yourself (it's just renaming files and syncing), but 
I wouldn't recommend it as standard practice, as it uses 3 times more 
diskspace and is quite slow.

And if methods 1 & 2 are "unsafe", then I think that there is a fundamental 
bug in the filesystem (I never believed "journaling" filesystems can work
100% correctly in the first place), despite what Theodore T'so says.

The filesystem should just work. The standard application programmer should 
never have to take into account the eventualities described there.

Michael.