<br><br><div class="gmail_quote">On Mon, May 21, 2012 at 5:40 PM, Ian Latter <span dir="ltr"><<a href="mailto:ian.latter@midnightcode.org" target="_blank">ian.latter@midnightcode.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
But they include an assumption.<br>
<br>
The query is: are async writes and reads sequential? The<br>
two specific cases are;<br>
<br>
1) Are all reads that are initiated in time after a write<br>
guaranteed to occur after that write has taken affect?<br></blockquote><div><br>Yes<br> <br></div><blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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2) Are all writes that are initiated in time after a write (x)<br>
guaranteed to occur after that write (x) has taken<br>
affect?<br></blockquote><div><br>Only overlapping offsets/regions retain causal ordering of completion. It is write-behind which acknowledges writes pre-maturely and therefore the layer which must maintain the 'effects' for further reads and writes by making the dependent IOs (overlapping offset/regions) wait for previous write's actual completion.<br>
<br>Avati<br><br></div></div>