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Re: UVM/genfs review

On Thu, Jan 15, 2009 at 07:42:07PM +0900, YAMAMOTO Takashi wrote:
> hi,
> > So this deadlock is independent of snapshots, fstrans_* etc are not
> > involved at all.
> is wapbl_begin in putpages necessary even without snapshots?

No, the only reason for this wapbl_begin is the copy-on-write for
snapshots where the block allocation has to be enclosed in wapbl_begin.

> btw, why did you exclude the pagedaemon from need_wapbl?

Because snapshots will not do copy-on-write for the pagedaemon and return
an error instead.

Still thinking that the wapbl design decision to use an exclusive lock
is wrong and a producer-consumer model would be moreappropriate...

Juergen Hannken-Illjes - - TU Braunschweig 

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