Re: deadlock bugfix for UFS needs testing. patch01

[Hiten Pandya <hmp@xxxxxxxxxxxxx>]

There are a few more softdep related bugfixes, which exist in FreeBSD.  I 
have ported those and tested them in my tree, being tested.

I will release those on this list once I finalise them as working, about 
one more week of testing.  I would like those go into RELEASE if they are 
deemed to be stable.

			Hiten Pandya
			hmp@xxxxxxxxxxxxx

Matthew Dillon wrote:
>     This patch is an attempt to fix a deadlock reported by Mitja Horvat
>     while running rtorrent.  I vaguely recall seeing a similar bug report
>     last year on rtorrent.
>
>     Our best analysis of the problem seems to show a deadlock between a
>     filesystem indirect block, a filesystem data block, and a VM page.
>     This patch attempts to unwind the deadlock.
>
>     The patch is somewhat dangerous simply due to the fact that it messes
>     with filesystem internals, so I would like to make it available
>     for wider testing for people who have test boxes setup that can afford
>     to lose their lunch (aka filesystem blowups).  The patch is against HEAD.
>
> 						-Matt