Re: tree corrupted on disk quota full

> 
> On Thu, 11 Jan 2007, Andy Whitcroft wrote:
>> The call was intended to replace a common idiom:
>>
>> if (xwrite(fd, buf, size) != size)
>> 	error
> 
> I really don't agree.
> 
> You should use "write_or_die()" for this idiom.
> 
> There really is two cases:
>  - the complex and robust one: "we will keep writing even in the presense 
>    of partial writes".
> 
>    This is "xwrite()". 
> 
>  - the simple case: "write everything", anything else is an error. This is 
>    "write_or_die()", or "write_in_full()".
> 
> And I claim, that for the "write_in_full()" case, if you EVER get anything 
> but the full length back, that's an error.
> 
> And it should be treated as such. There is NO POINT in write_in_full() 
> ever returning a partial result. It's unrecoverable by design - and if it 
> wasn't, you wouldn't use "write_in_full()" in the first place, you'd just 
> use "xwrite()".
> 
> And returning a partial result in that case is just a recipe for disaster. 
> I already pointed to one real bug due to this: write_buffer() was (and 
> currently is) simply buggy. And it's buggy EXACTLY becaue 
> "write_in_full()" was doing the wrong thing, and just made it easy to 
> write buggy code - it was no easier to use than xwrite(), and thus there 
> was no point to it. Might as well have just used xwrite() in the first 
> place.
> 
> So I repeat: either you use "xwrite()" (and handle the partial case), or 
> you use "write_in_full()" (and the partial case is an *ERROR*). There is 
> no sane middle ground in between those cases.