I understood that one of the benefits of deferred creation, was that a

later deletion could possibly end up with no disk i/o.  I was just

pointing out, that this is still not quite the case, since we need to

have enough data to later release the files data blocks... although I

guess a deleted files data-blocks could be allocated while only

marking their 'use' in in-memory-state (never writing it to disk).

However, this seems highly error-prone and not worth it.  As such the

above optimization can only really be done if we're deleting a file to

which there are no more open references...
On Mon, Nov 10, 2008 at 23:15, Daniel Phillips  wrote:

quoted text
> On Monday 10 November 2008 13:56, Maciej Żenczykowski wrote:

>> > two.  A file that is created and deleted before a delta transition

>> > takes place will not only never appear on disk, it will not even appear

>> > in a cached disk block.

>>

>> I'd like to point out, that if you create a file, open it, then delete

>> it, you can then still use it to store temporary data - this is indeed

>> a common use case.  However the amount of data storage may very well

>> exceed what you would be willing to store in ram, and thus you would

>> want to be able to write this data out to disk, even though the file

>> itself doesn't exist any more...  Some sort of swap-like behaviour???

>

> You mean an orphan temporary file?  I think we just need to make sure

> that works as it is supposed to.  It is reasonable for file data of

> such a file to be transferred to disk just like any other file, even

> though the file is unlinked.  We just need to be sure that it will get

> cleaned up like any other orphan.

>

> Daniel

>

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