Know your place [LWN.net]

Know your place

Posted Mar 18, 2009 8:55 UTC (Wed) by bojan (subscriber, #14302)
In reply to: Know your place by xoddam
Parent article: Better than POSIX?

> Appeal to authority, eh?

I don't know. I think a person that created the file system may know a thing a two about POSIX. I did actually go and check and he did appear to be right. But, that's obviously not good enough for you (or you may know of some interpretation we cannot grasp - it is possible). I'm OK with that.

> Please, bojan and tytso alike, cease and desist from saying applications are broken, when users have given a clear requirement for a new filesystem: that it not lose data as a matter of course, when the status quo would preserve it.

I have no intention of doing that (unless LWN editors throw me out). Likewise, you can say what you please.

Ted, being a pragmatic perseon, already did put workarounds in place, so users will be happy.

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Know your place

Posted Mar 30, 2009 12:37 UTC (Mon) by forthy (guest, #1525) [Link]

> I think a person that created the file system may know a thing a two about POSIX.

It's not, and I repeat in bold: NOT about POSIX. It is about reasonable behavior. Ordered data has been implemented in ReiserFS and XFS, which both had the reputation of being unstable and prone to eat files before. This is a quality of implementation issue, not a standard issue. Maybe we would need a better standard for file systems, so that quality of implementation is reasonable by default, but that's a different topic. If you insist that your way-below-average quality of implementation is "perfectly valid", you are anal-retentive.

I think Ted T'so should read the GNU Coding Standards. What is written there is mandatory for a core component of the GNU project (which the Linux kernel is, regardless if it's officially part of the GNU project). The point in question here is section 4.1:

The GNU Project regards standards published by other organizations as suggestions, not orders. We consider those standards, but we do not “obey” them. In developing a GNU program, you should implement an outside standard's specifications when that makes the GNU system better overall in an objective sense. When it doesn't, you shouldn't.

What Ted has implemented was a behavior which is standard, but makes his file system worse, because it has inconvenient side-effects on robustness in case of a crash. In shorter words: It sucks. And the GNU Coding Standards clearly say: If the standard sucks, don't follow it.