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Software components for data protection, secure storage and transfer

Post-events for delete and rename/ move callbacks

Also by EldoS: CallbackRegistry
A component to monitor and control Windows registry access and create virtual registry keys.
#10255
Posted: 06/01/2009 11:03:22
by Phil Nash (Standard support level)
Joined: 05/18/2009
Posts: 10

I notice your delete and rename/ move callbacks come in the pre-operation variety only (pre-delete and pre-rename).

Is there a technical reason this is so?

How can I tell if a the operation actually went ahead, or was vetoed further up the filter stack?
Without this information the events are effectively useless (except for vetoing), as there is no way to be sure if they led to any action. Just setting a timer to look at the file system later won't cut it as these operations (esp. deletes) can take a notoriously long time - and inconsistently so.

Thanks and regards,

Phil
#10262
Posted: 06/02/2009 12:31:04
by Vladimir Cherniga (EldoS Corp.)

By default notification events are called from the path when file system already has completed the request. Callback events are called from the path when file system request not yet handled by the underlying driver. This makes possible to modify requests before they will be sent further. The exception is done for Create, Read and Write callbacks. They are invoked in pre- and post- process path. But we could implement such behaviour for another callbacks in the future Callback Filter versions.
#10263
Posted: 06/03/2009 10:34:01
by Phil Nash (Standard support level)
Joined: 05/18/2009
Posts: 10

(that time I definitely subscribed for updates on this forum thread, but didn't get an email - I won't rely on that next time).

Thanks for the reply, Vladimir.

The most important thing first: Yes please - we would really like to have those post-event callbacks.

The reasoning is:

1. We need to do work both on the pre and post paths for delete and rename.
2. We cannot (currently, at least) subscribe to both callbacks and notifications for the same event.
3. As a result of (2) I have implemented my own notification system, so we only use your callbacks, which then post to a message queue for processing on another thread. Actually we need this anyway as we have a delay before processing where we coalesce continuous updates.

So the only way we can achieve what we need reliably is to have the post-process callbacks for rename and delete.

This is quite urgent for us - will it be possible to get it in the next release?

Thanks and regards,

Phil
#10264
Posted: 06/03/2009 12:28:11
by Vladimir Cherniga (EldoS Corp.)

Quote
Phil Nash wrote:
This is quite urgent for us - will it be possible to get it in the next release?


Sure, this is possible. We will add new postprocess callbacks for such requests. Preprocess callbacks remains with the same names and parameters as they are exists in the current version.

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