Re: [nfsv4] Issue 21: pnfs EOF handling

Black_David@emc.com wrote:

> The simplest fix may be to only issue CB_SIZECHANGED for an explicit
> SETATTR,
> and never for any implicit EOF change (write or commit).  A more
> comprehensive
> approach would be to add a "why" flag to CB_SIZECHANGED to distinguish
> implicit extension from explicit length set, although I can't immediately
> figure out why a pNFS client needs to see an implicit EOF change for file
> extension. 

[snip]

David, In the objects case, when the file is striped over multiple 
objects and the
client gets a read beyond its notion of the EOF it has to go read from 
storage
to determine the current file length or issue a GETATTR to the MDS.
If the file is holey and was sparsely written by another client beyond 
this client's
notion of the EOF it is possible that the client will get a short read 
from one
of the objects but there's more data in higher offsets on other objects.
In order to make this data visible the client needs to know the new EOF.

Benny

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