On 16/03/2015 11:52, Pawel Jakub Dawidek wrote:
On Mon, Mar 16, 2015 at 10:14:42AM +0000, Steven Hartland wrote:
On 16/03/2015 09:21, Matthew D. Fuller wrote:
On Mon, Mar 16, 2015 at 02:08:45AM +0100 I heard the voice of
Pawel Jakub Dawidek, and lo! it spake thus:
Overall the patch looks good. The main concern I have is that we do
nothing if the underlying provider returns EOPNOTSUPP on BIO_DELETE,
we will just keep sending those requests.
Well, they're all coming from the layer above us, and it'll get back
the EOPNOTSUPP's, so if it keeps sending them anyway that seems more
like its problem than ours. It seems like intercepting the response
(that would mean making our own new request, getting the response,
then making that response ourselves to the original?) wouldn't really
save much of anything, and adds a lot of extra bug-havens...
See how ZFS details with this, it adds internal state to the device
which stores and bypasses the pass down after the first EOPNOTSUPP.
This avoids the full stack round trip, which when volumes of deletes are
high could be noticeable.
By ZFS is at the top of the stack, GELI is just passing through the
requests. I agree with Matt that ZFS is the one who should handle
EOPNOTSUPP from the underlying provider, not GELI.
Ahh I see what he's saying now, thx.
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