[Tux3] Deferred Namespace Operations

Maciej Żenczykowski zenczykowski at gmail.com
Tue Nov 11 10:29:59 PST 2008

Ah, but that's precisely my point... having this data only in ram,
without the possibility to write it out to disk defeats the purpose of
using just-deleted files as disk-backed temporary storage.

On Tue, Nov 11, 2008 at 01:13, Daniel Phillips <phillips at phunq.net> wrote:
> On Monday 10 November 2008 23:50, Maciej Żenczykowski wrote:
>> 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...
> The data blocks will only be in the page cache (block cache in
> userspace) and not even be assigned physical addresses before the
> temporary file is deleted.  So they will just be removed from cache
> by the VFS.  It would be pretty useless if only empty files could hit
> this optimization.
> Regards,
> Daniel
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