[dm-devel] [patch] dm-mpath pg_init could race with destructor

[Mike Christie]

Lars Marowsky-Bree wrote:
> Why send a pg_init request at this point if there are no queued ios?
> This was in fact my solution, to only send a pg_init io if there are
> queued ios.
> 

Are there management situations where some admin wants to manually 
switch. If he was going to take a controller temporarily offline for 
maitnenance for example? Will multipath tools and dm-mutlipath be used 
to do this type of management, or will it be some vendor specific tool 
that sends a SG_IO directly?

It would not be possible to just have dm-multipath increment some 
refcount like pending so you cannot destroy things while a pg_init IO is 
in flight would it?