zfs discuss - May 2008 - Using O_EXCL flag on /dev/zvol nodes

The /dev/[r]dsk nodes implement the O_EXCL flag. If a node is opened using the
O_EXCL, subsequent open(2) to that node fail. But I dont think the same is true
for /dev/zvol/[r]dsk nodes. Is that a bug (or maybe RFE) ?

Thanks
Sumit
 
 
This message posted from opensolaris.org

Sumit Gupta wrote:
> The /dev/[r]dsk nodes implement the O_EXCL flag. If a node is opened using
>  the O_EXCL, subsequent open(2) to that node fail. But I dont think the 
> same is true for /dev/zvol/[r]dsk nodes. Is that a bug (or maybe RFE) ?
Yes, that seems like a fine RFE.  Or a bug, if there''s a policy saying
that
this must work.  A quick search didn''t turn up any documentation.

I think this would be implemented in zvol_open().  (Though it''s
unfortunate
that every device must implement this on its own; it would be better if the 
infrastructure took care of it.)

--matt