Re: stex driver panic in kernel 2.6.23

[Jens Axboe <jens.axboe@oracle.com>]

On Mon, Oct 29 2007, Ed Lin wrote:
> 
> >On Wed, Oct 24 2007, James Bottomley wrote:
> >> On Wed, 2007-10-24 at 12:17 -0700, Andrew Morton wrote:
> >> > On Wed, 24 Oct 2007 11:59:30 -0700 "Ed Lin" <ed.lin@promise.com> wrote:
> >> > 
> >> > > The shared tag issue was not fixed yet. Kernel panic
> >> > > happened while running I/O test in kernel 2.6.23
> >> > > (information attached). After applying the patch I posted
> >> > > (or the version James modified), panic disappeared.
> >> > > Switch back to standard kernel, panic again.
> >> > 
> >> > Did either of those patches get merged in 2.6.24-rc1?
> >> 
> >> No ... Jens did one instead (commit
> >> f3da54ba140c6427fa4a32913e1bf406f41b5dda), which now looks like it might
> >> not have fixed the issue.
> >
> >I think there's one more bug there, for shared maps. For the locking to
> >work, only the tag map and tag bit map may be shared (incidentally, I
> >was just explaining this to Nick yesterday, but I apparently didn't
> >review the code well enough myself). But we also share the busy list!
> >The busy_list must be queue private, or we need a block_queue_tag
> >covering lock as well.
> >
> >So we have to move the busy_list to the queue. This'll work fine, and
> >it'll actually also fix a problem with blk_queue_invalidate_tags() which
> >will invalidate tags across all shared queues. This is a bit confusing,
> >the low level driver should call it for each queue seperately since
> >otherwise you cannot kill tags on just a single queue for eg a hard
> >drive that stops responding. Since the function has no callers
> >currently, it's not an issue.
> >
> >Please test.
> >
> 
> With this patch the stex driver passed I/O test. So maybe this problem is
> fixed finally. Thanks. Please apply.

I do hope so... The patch is in Linus upstream tree now, will send a
variant for the stable series as well.

-- 
Jens Axboe